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Sample records for multiphoton spectral imaging

  1. Quantitative multiphoton spectral imaging and its use for measuring resonance energy transfer.

    PubMed

    Thaler, Christopher; Koushik, Srinagesh V; Blank, Paul S; Vogel, Steven S

    2005-10-01

    Protein labeling with green fluorescent protein derivatives has become an invaluable tool in cell biology. Protein quantification, however, is difficult when cells express constructs with overlapping fluorescent emissions. Under these conditions, signal separation using emission filters is inherently inefficient. Spectral imaging solves this problem by recording emission spectra directly. Unfortunately, linear unmixing, the algorithm used for quantifying individual fluorophores from emission spectra, fails when resonance energy transfer (RET) is present. We therefore sought to develop an unmixing algorithm that incorporates RET. An equation for spectral emission incorporating RET was derived and an assay based on this formalism, spectral RET (sRET), was developed. Standards with defined RET efficiencies and with known Cerulean/Venus ratios were constructed and used to test sRET. We demonstrate that sRET analysis is a comprehensive, photon-efficient method for imaging RET efficiencies and accurately determines donor and acceptor concentrations in living cells. PMID:16040744

  2. Quantitative multiphoton imaging

    NASA Astrophysics Data System (ADS)

    König, Karsten; Weinigel, Martin; Breunig, Hans Georg; Uchugonova, Aisada

    2014-02-01

    Certified clinical multiphoton tomographs for label-free multidimensional high-resolution in vivo imaging have been introduced to the market several years ago. Novel tomographs include a flexible 360° scan head attached to a mechanooptical arm for autofluorescence and SHG imaging as well as a CARS module. Non-fluorescent lipids and water, mitochondrial fluorescent NAD(P)H, fluorescent elastin, keratin, and melanin as well as SHG-active collagen can be imaged in vivo with submicron resolution in human skin. Sensitive and rapid detectors allow single photon counting and the construction of 3D maps where the number of detected photons per voxel is depicted. Intratissue concentration profiles from endogenous as well exogenous substances can be generated when the number of detected photons can be correlated with the number of molecules with respect to binding and scattering behavior. Furthermore, the skin ageing index SAAID based on the ratio elastin/collagen as well as the epidermis depth based on the onset of SHG generation can be determined.

  3. Spectral-resolved multifocal multiphoton microscopy with multianode photomultiplier tubes

    PubMed Central

    Cha, Jae Won; Tzeranis, Dimitrios; Subramanian, Jaichandar; Yannas, Ioannis V.; Nedivi, Elly; So, Peter T. C.

    2014-01-01

    Multiphoton excitation fluorescence microscopy is the preferred method for in vivo deep tissue imaging. Many biological applications demand both high imaging speed and the ability to resolve multiple fluorophores. One of the successful methods to improve imaging speed in a highly turbid specimen is multifocal multiphoton microscopy (MMM) based on use of multi-anode photomultiplier tubes (MAPMT). This approach improves imaging speed by using multiple foci for parallelized excitation without sacrificing signal to noise ratio (SNR) due to the scattering of emission photons. In this work, we demonstrate that the MAPMT based MMM can be extended with spectral resolved imaging capability. Instead of generating multiple excitation foci in a 2D grid pattern, a linear array of foci is generated. This leaves one axis of the 2D MAPMT available for spectral dispersion and detection. The spectral-resolved MMM can detect several emission signals simultaneously with high imaging speed optimized for high-throughput, high-contents applications. The new procedure is illustrated using imaging data from the kidney, peripheral nerve regeneration and dendritic morphological data from the brain. PMID:25321515

  4. Quantification of cellular autofluorescence of human skin using multiphoton tomography and fluorescence lifetime imaging in two spectral detection channels

    PubMed Central

    Patalay, Rakesh; Talbot, Clifford; Alexandrov, Yuriy; Munro, Ian; Neil, Mark A. A.; König, Karsten; French, Paul M. W.; Chu, Anthony; Stamp, Gordon W.; Dunsby, Chris

    2011-01-01

    We explore the diagnostic potential of imaging endogenous fluorophores using two photon microscopy and fluorescence lifetime imaging (FLIM) in human skin with two spectral detection channels. Freshly excised benign dysplastic nevi (DN) and malignant nodular Basal Cell Carcinomas (nBCCs) were excited at 760 nm. The resulting fluorescence signal was binned manually on a cell by cell basis. This improved the reliability of fitting using a double exponential decay model and allowed the fluorescence signatures from different cell populations within the tissue to be identified and studied. We also performed a direct comparison between different diagnostic groups. A statistically significant difference between the median mean fluorescence lifetime of 2.79 ns versus 2.52 ns (blue channel, 300-500 nm) and 2.08 ns versus 1.33 ns (green channel, 500-640 nm) was found between nBCCs and DN respectively, using the Mann-Whitney U test (p < 0.01). Further differences in the distribution of fluorescence lifetime parameters and inter-patient variability are also discussed. PMID:22162820

  5. Multiphoton imaging with a nanosecond supercontinuum source

    NASA Astrophysics Data System (ADS)

    Lefort, Claire; O'Connor, Rodney P.; Blanquet, Véronique; Baraige, Fabienne; Tombelaine, Vincent; Lévêque, Philippe; Couderc, Vincent; Leproux, Philippe

    2016-03-01

    Multiphoton microscopy is a well-established technique for biological imaging of several kinds of targets. It is classically based on multiphoton processes allowing two means of contrast simultaneously: two-photon fluorescence (TPF) and second harmonic generation (SHG). Today, the quasi exclusive laser technology used in that aim is femtosecond titanium sapphire (Ti: Sa) laser. We experimentally demonstrate that a nanosecond supercontinuum laser source (STM-250-VIS-IR-custom, Leukos, France; 1 ns, 600-2400 nm, 250 kHz, 1 W) allows to obtain the same kind of image quality in the case of both TPF and SHG, since it is properly filtered. The first set of images concerns the muscle of a mouse. It highlights the simultaneous detection of TPF and SHG. TPF is obtained thanks to the labelling of alpha-actinin with Alexa Fluor® 546 by immunochemistry. SHG is created from the non-centrosymmetric organization of myosin. As expected, discs of actin and myosin are superimposed alternatively. The resulting images are compared with those obtained from a standard femtosecond Ti: Sa source. The physical parameters of the supercontinuum are discussed. Finally, all the interest of using an ultra-broadband source is presented with images obtained in vivo on the brain of a mouse where tumor cells labeled with eGFP are grafted. Texas Red® conjugating Dextran is injected into the blood vessels network. Thus, two fluorophores having absorption wavelengths separated by 80 nm are imaged simultaneously with a single laser source.

  6. Multiphoton microscopy as a diagnostic imaging modality for lung cancer

    NASA Astrophysics Data System (ADS)

    Pavlova, Ina; Hume, Kelly R.; Yazinski, Stephanie A.; Peters, Rachel M.; Weiss, Robert S.; Webb, Watt W.

    2010-02-01

    Lung cancer is the leading killer among all cancers for both men and women in the US, and is associated with one of the lowest 5-year survival rates. Current diagnostic techniques, such as histopathological assessment of tissue obtained by computed tomography guided biopsies, have limited accuracy, especially for small lesions. Early diagnosis of lung cancer can be improved by introducing a real-time, optical guidance method based on the in vivo application of multiphoton microscopy (MPM). In particular, we hypothesize that MPM imaging of living lung tissue based on twophoton excited intrinsic fluorescence and second harmonic generation can provide sufficient morphologic and spectroscopic information to distinguish between normal and diseased lung tissue. Here, we used an experimental approach based on MPM with multichannel fluorescence detection for initial discovery that MPM spectral imaging could differentiate between normal and neoplastic lung in ex vivo samples from a murine model of lung cancer. Current results indicate that MPM imaging can directly distinguish normal and neoplastic lung tissues based on their distinct morphologies and fluorescence emission properties in non-processed lung tissue. Moreover, we found initial indication that MPM imaging differentiates between normal alveolar tissue, inflammatory foci, and lung neoplasms. Our long-term goal is to apply results from ex vivo lung specimens to aid in the development of multiphoton endoscopy for in vivo imaging of lung abnormalities in various animal models, and ultimately for the diagnosis of human lung cancer.

  7. Controllable infrared continuum source for multiphoton imaging

    NASA Astrophysics Data System (ADS)

    de Mauro, C.; Alfieri, D.; Arrigoni, M.; Armstrong, D.; Pavone, F. S.

    2010-02-01

    We report on multiphoton imaging of biological samples performed with continuum infrared source generated in photonic crystal fibers (PCFs). We studied the spectra generated in PCFs with dispersion profiles designed to maximize the power density in the 700-1000 nm region, where the two-photon absorption cross sections of the most common dyes lie. Pumping in normal dispersion region, with <140 femtosecond pulses delivered by a tunable Ti:Sa laser (Chameleon Ultra II by Coherent Inc.), results in a limitation of nonlinear broadening up to a mean power density above 2 mW/nm. Axial and lateral resolution obtained with a scanning multiphoton system has been measureed to be near the theoretical limit. The possibility of simultaneous two-photon excitation of different dyes in the same sample and high image resolution are demonstrated at tens of microns in depth. Signal-to-noise ratio and general performances are found to be comparable with those of a single wavelength system, used for comparison.

  8. Multiphoton imaging with high peak power VECSELs

    NASA Astrophysics Data System (ADS)

    Mirkhanov, Shamil; Quarterman, Adrian H.; Swift, Samuel; Praveen, Bavishna B.; Smyth, Conor J. C.; Wilcox, Keith G.

    2016-03-01

    Multiphoton imaging (MMPI) has become one of thee key non-invasive light microscopy techniques. This technique allows deep tissue imaging with high resolution and less photo-damage than conventional confocal microscopy. MPI is type of laser-scanning microscopy that employs localized nonlinear excitation, so that fluorescence is excited only with is scanned focal volume. For many years, Ti: sapphire femtosecond lasers have been the leading light sources for MPI applications. However, recent developments in laser sources and new types of fluorophores indicate that longer wavelength excitation could be a good alternative for these applications. Mode-locked VECSEELs have the potential to be low cost, compact light sources for MPI systems, with the additional advantage of broad wavelength coverage through use of different semiconductor material systems. Here, we use a femtosecond fibber laser to investigate the effect average power and repetition rate has on MPI image quality, to allow us to optimize our mode-locked VVECSELs for MPI.

  9. Cell-based and in vivo spectral analysis of fluorescent proteins for multiphoton microscopy

    NASA Astrophysics Data System (ADS)

    Salomonnson, Emma; Mihalko, Laura Anne; Verkhusha, Vladislav V.; Luker, Kathryn E.; Luker, Gary D.

    2012-09-01

    Multiphoton microscopy of cells and subcellular structures labeled with fluorescent proteins is the state-of-the-art technology for longitudinal imaging studies in tissues and living animals. Successful analysis of separate cell populations or signaling events by intravital microscopy requires optimal pairing of multiphoton excitation wavelengths with spectrally distinct fluorescent proteins. While prior studies have analyzed two photon absorption properties of isolated fluorescent proteins, there is limited information about two photon excitation and fluorescence emission profiles of fluorescent proteins expressed in living cells and intact tissues. Multiphoton microscopy was used to analyze fluorescence outputs of multiple blue, green, and red fluorescent proteins in cultured cells and orthotopic tumor xenografts of human breast cancer cells. It is shown that commonly used orange and red fluorescent proteins are excited efficiently by 750 to 760 nm laser light in living cells, enabling dual color imaging studies with blue or cyan proteins without changing excitation wavelength. It is also shown that small incremental changes in excitation wavelength significantly affect emission intensities from fluorescent proteins, which can be used to optimize multi-color imaging using a single laser wavelength. These data will direct optimal selection of fluorescent proteins for multispectral two photon microscopy.

  10. Spectral behavior of second harmonic signals from organic and non-organic materials in multiphoton microscopy

    PubMed Central

    Ehmke, Tobias; Knebl, Andreas; Reiss, Stephan; Fischinger, Isaak R.; Seiler, Theo G.; Stachs, Oliver; Heisterkamp, Alexander

    2015-01-01

    Multimodal nonlinear microscopy allows imaging of highly ordered biological tissue due to spectral separation of nonlinear signals. This requires certain knowledge about the spectral distribution of the different nonlinear signals. In contrast to several publications we demonstrate a factor of 122 relating the full width at half maximum of a gaussian laser pulse spectrum to the corresponding second harmonic pulse spectrum in the spatial domain by using a simple theoretical model. Experiments on monopotassium phosphate crystals (KDP-crystals) and on porcine corneal tissue support our theoretical predictions. Furthermore, no differences in spectral width were found for epi- and trans-detection of the second harmonic signal. Overall, these results may help to build an optimized multiphoton setup for spectral separation of nonlinear signals. PMID:26339527

  11. Multiphoton imaging of biological samples during freezing and heating

    NASA Astrophysics Data System (ADS)

    Breunig, H. G.; Uchugonova, A.; König, K.

    2014-02-01

    We applied multiphoton microscopic imaging to observe freezing and heating effects in plant- and animal cell samples. The experimental setups consisted of a multiphoton imaging system and a heating and cooling stage which allows for precise temperature control from liquid nitrogen temperature (-196°C 77 K) up to +600°C (873 K) with heating/freezing rates between 0.01 K/min and 150 K/min. Two multiphoton imaging systems were used: a system based on a modified optical microscope and a flexible mobile system. To illustrate the imaging capabilities, plant leafs as well as animal cells were microscopically imaged in vivo during freezing based on autofluorescence lifetime and intensity of intrinsic molecules. The measurements illustrate the usefulness of multiphoton imaging to investigate freezing effects on animal and plant cells.

  12. Optical clearing and multiphoton imaging of paraffin-embedded specimens

    NASA Astrophysics Data System (ADS)

    Wilson, Jesse W.; Degan, Simone; Fischer, Martin C.; Warren, Warren S.

    2013-02-01

    New labeling, imaging, or analysis tools could provide new retrospective insights when applied to archived, paraffin-embedded samples. Deep-tissue multiphoton microscopy of paraffin-embedded specimens is achieved using optical clearing with mineral oil. We tested a variety of murine tissue specimens including skin, lung, spleen, kidney, and heart, acquiring multiphoton autofluorescence and second-harmonic generation, and pump-probe images This technique introduces the capability for non-destructive 3-dimensional microscopic imaging of existing archived pathology specimens, enabling retrospective studies.

  13. Coherence-Gated Sensorless Adaptive Optics Multiphoton Retinal Imaging

    PubMed Central

    Cua, Michelle; Wahl, Daniel J.; Zhao, Yuan; Lee, Sujin; Bonora, Stefano; Zawadzki, Robert J.; Jian, Yifan; Sarunic, Marinko V.

    2016-01-01

    Multiphoton microscopy enables imaging deep into scattering tissues. The efficient generation of non-linear optical effects is related to both the pulse duration (typically on the order of femtoseconds) and the size of the focused spot. Aberrations introduced by refractive index inhomogeneity in the sample distort the wavefront and enlarge the focal spot, which reduces the multiphoton signal. Traditional approaches to adaptive optics wavefront correction are not effective in thick or multi-layered scattering media. In this report, we present sensorless adaptive optics (SAO) using low-coherence interferometric detection of the excitation light for depth-resolved aberration correction of two-photon excited fluorescence (TPEF) in biological tissue. We demonstrate coherence-gated SAO TPEF using a transmissive multi-actuator adaptive lens for in vivo imaging in a mouse retina. This configuration has significant potential for reducing the laser power required for adaptive optics multiphoton imaging, and for facilitating integration with existing systems. PMID:27599635

  14. Coherence-Gated Sensorless Adaptive Optics Multiphoton Retinal Imaging.

    PubMed

    Cua, Michelle; Wahl, Daniel J; Zhao, Yuan; Lee, Sujin; Bonora, Stefano; Zawadzki, Robert J; Jian, Yifan; Sarunic, Marinko V

    2016-01-01

    Multiphoton microscopy enables imaging deep into scattering tissues. The efficient generation of non-linear optical effects is related to both the pulse duration (typically on the order of femtoseconds) and the size of the focused spot. Aberrations introduced by refractive index inhomogeneity in the sample distort the wavefront and enlarge the focal spot, which reduces the multiphoton signal. Traditional approaches to adaptive optics wavefront correction are not effective in thick or multi-layered scattering media. In this report, we present sensorless adaptive optics (SAO) using low-coherence interferometric detection of the excitation light for depth-resolved aberration correction of two-photon excited fluorescence (TPEF) in biological tissue. We demonstrate coherence-gated SAO TPEF using a transmissive multi-actuator adaptive lens for in vivo imaging in a mouse retina. This configuration has significant potential for reducing the laser power required for adaptive optics multiphoton imaging, and for facilitating integration with existing systems. PMID:27599635

  15. Nonlinear optical imaging characteristics of colonic adenocarcinoma using multiphoton microscopy

    NASA Astrophysics Data System (ADS)

    Liu, Nenrong; Chen, Rong; Li, Hongsheng; Chen, Jianxin

    2012-12-01

    Multiphoton microscopy (MPM), a noninvasive optical method with high resolution and high sensitivity, can obtain detailed microstructures of biotissues at submolecular level. In this study, MPM is used to image microstructure varieties of human colonic mucosa and submucosa with adenocarcinoma. Some parameters, such as gland configuration, SHG/TPEF intensity ratio, and collagen orientation and so on, should serve the indicators of early colorectal cancer. The exploratory results show that it's potential for the development of multiphoton mini-endoscopy in real-time early diagnosis of colorectal cancer.

  16. Photonic near-field imaging in multiphoton photoemission electron microscopy

    NASA Astrophysics Data System (ADS)

    Fitzgerald, J. P. S.; Word, R. C.; Saliba, S. D.; Könenkamp, R.

    2013-05-01

    We report the observation of optical near fields in a photonic waveguide of conductive indium tin oxide (ITO) using multiphoton photoemission electron microscopy (PEEM). Nonlinear two-photon photoelectron emission is enhanced at field maxima created by interference between incident 410-nm and coherently excited guided photonic waves, providing strong phase contrast. Guided modes are observed under both transverse magnetic field (TM) and transverse electric field (TE) polarized illuminations and are consistent with classical electromagnetic theory. Implications on the role of multiphoton PEEM in optical near-field imaging are discussed.

  17. Multiphoton Imaging of Ultrasound Bioeffects in the Murine Brain

    NASA Astrophysics Data System (ADS)

    Raymond, Scott; Skoch, Jesse; Bacskai, Brian; Hynynen, Kullervo

    2006-05-01

    The purpose of this study was to demonstrate the feasibility of multiphoton imaging in the murine brain during exposure to ultrasound. Our experimental setup coupled ultrasound through the ventral surface of the mouse while allowing imaging through a cranial window from the dorsal surface. Field attenuation was estimated by scanning the field after insertion of a freshly sacrificed mouse; beam profile and peak position were preserved, suggesting adequate targeting for imaging experiments. C57 mice were imaged with a Biorad multiphoton microscope while being exposed to ultrasound (f = 1.029 MHz, peak pressure ˜ 200 kPa, average power ˜ 0.18 W) with IV injection of Optison. We observed strong vasoconstriction coincident with US and Optison, as well as permeabilization of the blood-brain barrier.

  18. Moxifloxacin: Clinically compatible contrast agent for multiphoton imaging

    PubMed Central

    Wang, Taejun; Jang, Won Hyuk; Lee, Seunghun; Yoon, Calvin J.; Lee, Jun Ho; Kim, Bumju; Hwang, Sekyu; Hong, Chun-Pyo; Yoon, Yeoreum; Lee, Gilgu; Le, Viet-Hoan; Bok, Seoyeon; Ahn, G-One; Lee, Jaewook; Gho, Yong Song; Chung, Euiheon; Kim, Sungjee; Jang, Myoung Ho; Myung, Seung-Jae; Kim, Myoung Joon; So, Peter T. C.; Kim, Ki Hean

    2016-01-01

    Multiphoton microscopy (MPM) is a nonlinear fluorescence microscopic technique widely used for cellular imaging of thick tissues and live animals in biological studies. However, MPM application to human tissues is limited by weak endogenous fluorescence in tissue and cytotoxicity of exogenous probes. Herein, we describe the applications of moxifloxacin, an FDA-approved antibiotic, as a cell-labeling agent for MPM. Moxifloxacin has bright intrinsic multiphoton fluorescence, good tissue penetration and high intracellular concentration. MPM with moxifloxacin was demonstrated in various cell lines, and animal tissues of cornea, skin, small intestine and bladder. Clinical application is promising since imaging based on moxifloxacin labeling could be 10 times faster than imaging based on endogenous fluorescence. PMID:27283889

  19. Moxifloxacin: Clinically compatible contrast agent for multiphoton imaging.

    PubMed

    Wang, Taejun; Jang, Won Hyuk; Lee, Seunghun; Yoon, Calvin J; Lee, Jun Ho; Kim, Bumju; Hwang, Sekyu; Hong, Chun-Pyo; Yoon, Yeoreum; Lee, Gilgu; Le, Viet-Hoan; Bok, Seoyeon; Ahn, G-One; Lee, Jaewook; Gho, Yong Song; Chung, Euiheon; Kim, Sungjee; Jang, Myoung Ho; Myung, Seung-Jae; Kim, Myoung Joon; So, Peter T C; Kim, Ki Hean

    2016-01-01

    Multiphoton microscopy (MPM) is a nonlinear fluorescence microscopic technique widely used for cellular imaging of thick tissues and live animals in biological studies. However, MPM application to human tissues is limited by weak endogenous fluorescence in tissue and cytotoxicity of exogenous probes. Herein, we describe the applications of moxifloxacin, an FDA-approved antibiotic, as a cell-labeling agent for MPM. Moxifloxacin has bright intrinsic multiphoton fluorescence, good tissue penetration and high intracellular concentration. MPM with moxifloxacin was demonstrated in various cell lines, and animal tissues of cornea, skin, small intestine and bladder. Clinical application is promising since imaging based on moxifloxacin labeling could be 10 times faster than imaging based on endogenous fluorescence. PMID:27283889

  20. Moxifloxacin: Clinically compatible contrast agent for multiphoton imaging

    NASA Astrophysics Data System (ADS)

    Wang, Taejun; Jang, Won Hyuk; Lee, Seunghun; Yoon, Calvin J.; Lee, Jun Ho; Kim, Bumju; Hwang, Sekyu; Hong, Chun-Pyo; Yoon, Yeoreum; Lee, Gilgu; Le, Viet-Hoan; Bok, Seoyeon; Ahn, G.-One; Lee, Jaewook; Gho, Yong Song; Chung, Euiheon; Kim, Sungjee; Jang, Myoung Ho; Myung, Seung-Jae; Kim, Myoung Joon; So, Peter T. C.; Kim, Ki Hean

    2016-06-01

    Multiphoton microscopy (MPM) is a nonlinear fluorescence microscopic technique widely used for cellular imaging of thick tissues and live animals in biological studies. However, MPM application to human tissues is limited by weak endogenous fluorescence in tissue and cytotoxicity of exogenous probes. Herein, we describe the applications of moxifloxacin, an FDA-approved antibiotic, as a cell-labeling agent for MPM. Moxifloxacin has bright intrinsic multiphoton fluorescence, good tissue penetration and high intracellular concentration. MPM with moxifloxacin was demonstrated in various cell lines, and animal tissues of cornea, skin, small intestine and bladder. Clinical application is promising since imaging based on moxifloxacin labeling could be 10 times faster than imaging based on endogenous fluorescence.

  1. In vivo multiphoton tomography and fluorescence lifetime imaging of human brain tumor tissue.

    PubMed

    Kantelhardt, Sven R; Kalasauskas, Darius; König, Karsten; Kim, Ella; Weinigel, Martin; Uchugonova, Aisada; Giese, Alf

    2016-05-01

    High resolution multiphoton tomography and fluorescence lifetime imaging differentiates glioma from adjacent brain in native tissue samples ex vivo. Presently, multiphoton tomography is applied in clinical dermatology and experimentally. We here present the first application of multiphoton and fluorescence lifetime imaging for in vivo imaging on humans during a neurosurgical procedure. We used a MPTflex™ Multiphoton Laser Tomograph (JenLab, Germany). We examined cultured glioma cells in an orthotopic mouse tumor model and native human tissue samples. Finally the multiphoton tomograph was applied to provide optical biopsies during resection of a clinical case of glioblastoma. All tissues imaged by multiphoton tomography were sampled and processed for conventional histopathology. The multiphoton tomograph allowed fluorescence intensity- and fluorescence lifetime imaging with submicron spatial resolution and 200 picosecond temporal resolution. Morphological fluorescence intensity imaging and fluorescence lifetime imaging of tumor-bearing mouse brains and native human tissue samples clearly differentiated tumor and adjacent brain tissue. Intraoperative imaging was found to be technically feasible. Intraoperative image quality was comparable to ex vivo examinations. To our knowledge we here present the first intraoperative application of high resolution multiphoton tomography and fluorescence lifetime imaging of human brain tumors in situ. It allowed in vivo identification and determination of cell density of tumor tissue on a cellular and subcellular level within seconds. The technology shows the potential of rapid intraoperative identification of native glioma tissue without need for tissue processing or staining. PMID:26830089

  2. Multiphoton imaging: a view to understanding sulfur mustard lesions

    NASA Astrophysics Data System (ADS)

    Werrlein, Robert J. S.; Madren-Whalley, Janna S.

    2003-07-01

    It is well known that topical exposure to sulfur mustard (SM) produces persistent, incapacitating blisters of the skin. However, the primary lesions effecting epidermal-dermal separation and disabling of mechanisms for cutaneous repair remain uncertain. Immunofluorescent staining plus multiphoton imaging of human epidermal tissues and keratinocytes exposed to SM (400 μM x 5 min)have revealed that SM disrupts adhesion-complex molecules which are also disrupted by epidermolysis bullosa-type blistering diseases of the skin. Images of keratin-14 showed early, progressive, postexposure collapse of the K5/K14 cytoskeleton that resulted in ventral displacement of the nuclei beneath its collapsing filaments. This effectively corrupted the dynamic filament assemblies that link basal-cell nuclei to the extracellular matrix via α6β4-integrin and laminin-5. At 1 h postexposure, there was disruption in the surface organization of α6β4 integrins, associated displacement of laminin-5 anchoring sites and a concomitant loss of functional asymmetry. Accordingly, our multiphoton images are providing compelling evidence that SM induces prevesicating lesions that disrupt the receptor-ligand organization and cytoskeletal systems required for maintaining dermal-epidermal attachment, signal transduction, and polarized mobility.

  3. Molecule-specific darkfield and multiphoton imaging using gold nanocages

    NASA Astrophysics Data System (ADS)

    Powless, Amy J.; Jenkins, Samir V.; McKay, Mary Lee; Chen, Jingyi; Muldoon, Timothy J.

    2015-03-01

    Due to their robust optical properties, biological inertness, and readily adjustable surface chemistry, gold nanostructures have been demonstrated as contrast agents in a variety of biomedical imaging applications. One application is dynamic imaging of live cells using bioconjugated gold nanoparticles to monitor molecule trafficking mechanisms within cells; for instance, the regulatory pathway of epidermal growth factor receptor (EGFR) undergoing endocytosis. In this paper, we have demonstrated a method to track endocytosis of EGFR in MDA-MB-468 breast adenocarcinoma cells using bioconjugated gold nanocages (AuNCs) and multiphoton microscopy. Dynamic imaging was performed using a time series capture of 4 images every minute for one hour. Specific binding and internalization of the bioconjugated AuNCs was observed while the two control groups showed non-specific binding at fewer surface sites, leading to fewer bound AuNCs and no internalization.

  4. Multibeam multifocal multiphoton photon counting imaging in scattering media

    NASA Astrophysics Data System (ADS)

    Hoover, Erich E.

    Multiphoton microscopy is an invaluable technique for the neurological community, allowing for deep explorations within highly scattering tissues such as the brain. However, prior to this research multiphoton microscopy was limited in its ability to rapidly construct volumetric images deep within scattering specimens. This work establishes a technique that permits such exploration through the application of multiple beams separated in both space and time, where signal photons corresponding to those beams are demultiplexed through the use of a field programmable gate array. With this system a number of improvements are provided to research in scattering media, including the coveted ability to perform photon-counting imaging with multiple beams. The ability to perform these measurements with multiple beams permits unique quantitative measurements of fluorophores within living specimens, allowing new research into dynamic three-dimensional behavior occurring within the brain. Additionally, the ability to perform multimodal measurements without filtering allows for unique avenues of research where the harmonic generation is indistinguishable from the two-photon excited fluorescence. These improvements provide neuroscience researchers with a large assortment of technological tools that will permit them to perform numerous novel experiments within the brain and other highly-scattering specimens, which should one day lead to significant advances in our understanding of complex neuronal activity.

  5. Live-Animal Imaging of Renal Function by Multiphoton Microscopy

    PubMed Central

    Dunn, Kenneth W.; Sutton, Timothy A.; Sandoval, Ruben M.

    2015-01-01

    Intravital microscopy, microscopy of living animals, is a powerful research technique that combines the resolution and sensitivity found in microscopic studies of cultured cells with the relevance and systemic influences of cells in the context of the intact animal. The power of intravital microscopy has recently been extended with the development of multiphoton fluorescence microscopy systems capable of collecting optical sections from deep within the kidney at subcellular resolution, supporting high-resolution characterizations of the structure and function of glomeruli, tubules, and vasculature in the living kidney. Fluorescent probes are administered to an anesthetized, surgically prepared animal, followed by image acquisition for up to 3 hr. Images are transferred via a high-speed network to specialized computer systems for digital image analysis. This general approach can be used with different combinations of fluorescent probes to evaluate processes such as glomerular permeability, proximal tubule endocytosis, microvascular flow, vascular permeability, mitochondrial function, and cellular apoptosis/necrosis. PMID:23042524

  6. Achieving molecular selectivity in imaging using multiphoton Raman spectroscopy techniques

    SciTech Connect

    Holtom, Gary R. ); Thrall, Brian D. ); Chin, Beek Yoke ); Wiley, H Steven ); Colson, Steven D. )

    2000-12-01

    In the case of most imaging methods, contrast is generated either by physical properties of the sample (Differential Image Contrast, Phase Contrast), or by fluorescent labels that are localized to a particular protein or organelle. Standard Raman and infrared methods for obtaining images are based upon the intrinsic vibrational properties of molecules, and thus obviate the need for attached flurophores. Unfortunately, they have significant limitations for live-cell imaging. However, an active Raman method, called Coherent Anti-Stokes Raman Scattering (CARS), is well suited for microscopy, and provides a new means for imaging specific molecules. Vibrational imaging techniques, such as CARS, avoid problems associated with photobleaching and photo-induced toxicity often associated with the use of fluorescent labels with live cells. Because the laser configuration needed to implement CARS technology is similar to that used in other multiphoton microscopy methods, such as two -photon fluorescence and harmonic generation, it is possible to combine imaging modalities, thus generating simultaneous CARS and fluorescence images. A particularly powerful aspect of CARS microscopy is its ability to selectively image deuterated compounds, thus allowing the visualization of molecules, such as lipids, that are chemically indistinguishable from the native species.

  7. Direct trabecular meshwork imaging in porcine eyes through multiphoton gonioscopy

    NASA Astrophysics Data System (ADS)

    Masihzadeh, Omid; Ammar, David A.; Kahook, Malik Y.; Gibson, Emily A.; Lei, Tim C.

    2013-03-01

    The development of technologies to characterize the ocular aqueous outflow system (AOS) is important for the understanding of the pathophysiology of glaucoma. Multiphoton microscopy (MPM) offers the advantage of high-resolution, label-free imaging with intrinsic image contrast because the emitted signals result from the specific biomolecular content of the tissue. Previous attempts to use MPM to image the murine irido-corneal region directly through the sclera have suffered from degradation in image resolution due to scattering of the focused laser light. As a result, transscleral MPM has limited ability to observe fine structures in the AOS. In this work, the porcine irido-corneal angle was successfully imaged through the transparent cornea using a gonioscopic lens to circumvent the highly scattering scleral tissue. The resulting high-resolution images allowed the detailed structures in the trabecular meshwork (TM) to be observed. Multimodal imaging by two-photon autofluorescence and second harmonic generation allowed visualization of different features in the TM without labels and without disruption of the TM or surrounding tissues. MPM gonioscopy is a promising noninvasive imaging tool for high-resolution studies of the AOS, and research continues to explore the potential for future clinical applications in humans.

  8. Multiphoton gonioscopy to image the trabecular meshwork of porcine eyes

    NASA Astrophysics Data System (ADS)

    Masihzadeh, Omid; Ammar, David A.; Kahook, Malik Y.; Gibson, Emily A.; Lei, Tim C.

    2013-03-01

    The aqueous outflow system (AOS), including the trabecular meshwork (TM), the collector channels (CC) and the Schlemm's canal (SC), regulates intraocular pressure (IOP) through the drainage of the aqueous humor (AH). Abnormal IOP elevation leads to increased pressure stress to retinal ganglion cells, resulting in cell loss that can ultimately lead to complete loss of eyesight. Therefore, development of imaging tools to detect abnormal structural and functional changes of the AOS is important in early diagnosis and prevention of glaucoma. Multiphoton microscopy (MPM), including twophoton autofluorescence (TPAF) and second harmonic generation (SHG), is a label-free microscopic technique that allows molecular specific imaging of biological tissues like the TM. Since the TM and other AOS structures are located behind the highly scattering scleral tissue, transscleral imaging of the TM does not provide enough optical resolution. In this work, a gonioscopic lens is used to allow direct optical access of the TM through the cornea for MPM imaging. Compared to transscleral imaging, the acquired MPM images show improved resolution as individual collagen fiber bundles of the TM can be observed. MPM gonioscopy may have the potential to be developed as a future clinical imaging tool for glaucoma diagnostics.

  9. High-Resolution Multiphoton Imaging of Tumors In Vivo

    PubMed Central

    Wyckoff, Jeffrey; Gligorijevic, Bojana; Entenberg, David; Segall, Jeffrey; Condeelis, John

    2014-01-01

    Analysis of the individual steps in metastasis is crucial if insights at the molecular level are to be linked to the cell biology of cancer. A technical hurdle to achieving the analysis of the individual steps of metastasis is the fact that, at the gross level, tumors are heterogeneous in both animal models and patients. Human primary tumors show extensive variation in all properties ranging from growth and morphology of the tumor through tumor-cell density in the blood and formation and growth of metastases. Methods capable of the direct visualization and analysis of tumor-cell behavior at single-cell resolution in vivo have become crucial in advancing the understanding of mechanisms of metastasis, the definition of microenvironment, and the markers related to both. This article discusses the use of high-resolution multiphoton imaging of tumors (specifically breast tumors in mice) in vivo. PMID:21969629

  10. Superresolved multiphoton microscopy with spatial frequency-modulated imaging.

    PubMed

    Field, Jeffrey J; Wernsing, Keith A; Domingue, Scott R; Allende Motz, Alyssa M; DeLuca, Keith F; Levi, Dean H; DeLuca, Jennifer G; Young, Michael D; Squier, Jeff A; Bartels, Randy A

    2016-06-14

    Superresolved far-field microscopy has emerged as a powerful tool for investigating the structure of objects with resolution well below the diffraction limit of light. Nearly all superresolution imaging techniques reported to date rely on real energy states of fluorescent molecules to circumvent the diffraction limit, preventing superresolved imaging with contrast mechanisms that occur via virtual energy states, including harmonic generation (HG). We report a superresolution technique based on spatial frequency-modulated imaging (SPIFI) that permits superresolved nonlinear microscopy with any contrast mechanism and with single-pixel detection. We show multimodal superresolved images with two-photon excited fluorescence (TPEF) and second-harmonic generation (SHG) from biological and inorganic media. Multiphoton SPIFI (MP-SPIFI) provides spatial resolution up to 2η below the diffraction limit, where η is the highest power of the nonlinear intensity response. MP-SPIFI can be used to provide enhanced resolution in optically thin media and may provide a solution for superresolved imaging deep in scattering media. PMID:27231219

  11. Multiphoton and photothermal imaging of molecular events in cancer

    NASA Astrophysics Data System (ADS)

    Skala, Melissa

    2010-10-01

    Optical techniques are attractive for monitoring disease processes in living tissues because they are relatively cheap, non-invasive and provide a wealth of functional information. Multiphoton microscopy (MPM) and Optical Coherence Tomography (OCT) are two types of three-dimensional optical imaging modalities that have demonstrated great utility in pre-clinical models of disease. These techniques are particularly useful for identifying metabolic and molecular biomarkers in cancer. These biomarkers can be used to identify the mechanisms of tumor growth, and to predict the response of a particular tumor to treatment. Specifically, MPM of the co-enzymes NADH and FAD was used to quantify metabolic changes associated with developing cancers in vivo. This imaging technique exploits intrinsic sources of tissue contrast and thus does not require contrast agents. Ongoing work combines this metabolic imaging technique with vascular imaging to provide a comprehensive picture of oxygen supply and demand with tumor therapy. Molecular signaling represents a third critical component in tumor physiology. To this end we have recently developed photothermal OCT, which combines coherent detection with laser-heated gold nanoparticles to achieve high-resolution molecular contrast at deeper depths than MPM. This multi-functional imaging platform will provide unprecedented insight into oxygen supply and demand, and molecular signaling in response to tumor growth and targeted cancer therapies in pre-clinical models.

  12. Water-Soluble Quantum Dots for Multiphoton Fluorescence Imaging in Vivo

    NASA Astrophysics Data System (ADS)

    Larson, Daniel R.; Zipfel, Warren R.; Williams, Rebecca M.; Clark, Stephen W.; Bruchez, Marcel P.; Wise, Frank W.; Webb, Watt W.

    2003-05-01

    The use of semiconductor nanocrystals (quantum dots) as fluorescent labels for multiphoton microscopy enables multicolor imaging in demanding biological environments such as living tissue. We characterized water-soluble cadmium selenide-zinc sulfide quantum dots for multiphoton imaging in live animals. These fluorescent probes have two-photon action cross sections as high as 47,000 Goeppert-Mayer units, by far the largest of any label used in multiphoton microscopy. We visualized quantum dots dynamically through the skin of living mice, in capillaries hundreds of micrometers deep. We found no evidence of blinking (fluorescence intermittency) in solution on nanosecond to millisecond time scales.

  13. Water-soluble quantum dots for multiphoton fluorescence imaging in vivo.

    PubMed

    Larson, Daniel R; Zipfel, Warren R; Williams, Rebecca M; Clark, Stephen W; Bruchez, Marcel P; Wise, Frank W; Webb, Watt W

    2003-05-30

    The use of semiconductor nanocrystals (quantum dots) as fluorescent labels for multiphoton microscopy enables multicolor imaging in demanding biological environments such as living tissue. We characterized water-soluble cadmium selenide-zinc sulfide quantum dots for multiphoton imaging in live animals. These fluorescent probes have two-photon action cross sections as high as 47,000 Goeppert-Mayer units, by far the largest of any label used in multiphoton microscopy. We visualized quantum dots dynamically through the skin of living mice, in capillaries hundreds of micrometers deep. We found no evidence of blinking (fluorescence intermittency) in solution on nanosecond to millisecond time scales. PMID:12775841

  14. Multiphoton imaging with a novel compact diode-pumped Ti:sapphire oscillator.

    PubMed

    König, Karsten; Andersen, Peter; Le, Tuan; Breunig, Hans Georg

    2015-12-01

    Multiphoton laser scanning microscopy commonly relies on bulky and expensive femtosecond lasers. We integrated a novel minimal-footprint Ti:sapphire oscillator, pumped by a frequency-doubled distributed Bragg reflector tapered diode laser, into a clinical multiphoton tomograph and evaluated its imaging capability using different biological samples, i.e. cell monolayers, corneal tissue, and human skin. With the novel laser, the realization of very compact Ti:sapphire-based systems for high-quality multiphoton imaging at a significantly size and weight compared to current systems will become possible. PMID:26534831

  15. 2D simultaneous spatial and temporal focusing multiphoton microscopy for fast volume imaging with improved sectioning ability

    NASA Astrophysics Data System (ADS)

    Song, Qiyuan; Isobe, Keisuke; Hirosawa, Kenichi; Midorikawa, Katsumi; Kannari, Fumihiko

    2015-03-01

    Simultaneous spatial and temporal focusing (SSTF) multiphoton microscopy offers us widefield imaging with sectioning ability. As extending the idea to 2D SSTF, people can utilize a 2D spectral disperser. In this study, we use a 2D spectral disperser via a virtually-imaged phased-array (VIPA) and a diffraction grating to fulfill the back aperture of objective lens with a spectrum matrix. This offers us an axial resolution enhanced by a factor of ~1.7 compared with conventional SSTF microscopy. Furthermore, the small free spectral range (FSR) of VIPA will reduce the temporal self-imaging effect around out-of-focus region and thus will reduce the out-of-focus multiphoton excited fluorescence (MPEF) signal of 2D SSTF microscopy. We experimentally show that inside a sample with dense MPEF, the contrast of the sectioning image is increased in our 2D SSTF microscope compared with SSTF microscope. In our microscope, we use a 1 kHz chirped amplification laser, a piezo stage and a sCMOS camera integrated with 2D SSTF to realize high speed volume imaging at a speed of 50 volumes per second as well as improved sectioning ability. Volume imaging of Brownian motions of fluorescent beads as small as 1μm has been demonstrated. Not only the lateral motion but also the axial motion could be traced.

  16. Multi Spectral Imaging System

    NASA Technical Reports Server (NTRS)

    Spiering, Bruce A. (Inventor)

    1999-01-01

    An optical imaging system provides automatic co-registration of a plurality of multi spectral images of an object which are generated by a plurality of video cameras or other optical detectors. The imaging system includes a modular assembly of beam splitters, lens tubes, camera lenses and wavelength selective filters which facilitate easy reconfiguration and adjustment of the system for various applications. A primary lens assembly generates a real image of an object to be imaged on a reticle which is positioned at a fixed length from a beam splitter assembly. The beam splitter assembly separates a collimated image beam received from the reticle into multiple image beams, each of which is projected onto a corresponding one of a plurality of video cameras. The lens tubes which connect the beam splitter assembly to the cameras are adjustable in length to provide automatic co-registration of the images generated by each camera.

  17. Multipurpose spectral imager.

    PubMed

    Sigernes, F; Lorentzen, D A; Heia, K; Svenøe, T

    2000-06-20

    A small spectral imaging system is presented that images static or moving objects simultaneously as a function of wavelength. The main physical principle is outlined and demonstrated. The instrument is capable of resolving both spectral and spatial information from targets throughout the entire visible region. The spectral domain has a bandpass of 12 A. One can achieve the spatial domain by rotating the system's front mirror with a high-resolution stepper motor. The spatial resolution range from millimeters to several meters depends mainly on the front optics used and whether the target is fixed (static) or movable relative to the instrument. Different applications and examples are explored, including outdoor landscapes, industrial fish-related targets, and ground-level objects observed in the more traditional way from an airborne carrier (remote sensing). Through the examples, we found that the instrument correctly classifies whether a shrimp is peeled and whether it can disclose the spectral and spatial microcharacteristics of targets such as a fish nematode (parasite). In the macroregime, we were able to distinguish a marine vessel from the surrounding sea and sky. A study of the directional spectral albedo from clouds, mountains, snow cover, and vegetation has also been included. With the airborne experiment, the imager successfully classified snow cover, leads, and new and rafted ice, as seen from 10.000 ft (3.048 m). PMID:18345245

  18. Multiphoton imaging the disruptive nature of sulfur mustard lesions

    NASA Astrophysics Data System (ADS)

    Werrlein, Robert J.; Braue, Catherine R.; Dillman, James F.

    2005-03-01

    Sulfur mustard [bis-2-chloroethyl sulfide] is a vesicating agent first used as a weapon of war in WWI. It causes debilitating blisters at the epidermal-dermal junction and involves molecules that are also disrupted by junctional epidermolysis bullosa (JEB) and other blistering skin diseases. Despite its recurring use in global conflicts, there is still no completely effective treatment. We have shown by imaging human keratinocytes in cell culture and in intact epidermal tissues that the basal cells of skin contain well-organized molecules (keratins K5/K14, α6β4 integrin, laminin 5 and α3β1 integrin) that are early targets of sulfur mustard. Disruption and collapse of these molecules is coincident with nuclear displacement, loss of functional asymmetry, and loss of polarized mobility. The progression of this pathology precedes basal cell detachment by 8-24 h, a time equivalent to the "clinical latent phase" that defines the extant period between agent exposure and vesication. Our images indicate that disruption of adhesion-complex molecules also impairs cytoskeletal proteins and the integration of structures required for signal transduction and tissue repair. We have recently developed an optical system to test this hypothesis, i.e., to determine whether and how the early disruption of target molecules alters signal transduction. This environmentally controlled on-line system provides a nexus for real-time correlation of imaged lesions with DNA microarray analysis, and for using multiphoton microscopy to facilitate development of more effective treatment strategies.

  19. Invited Review Article: Imaging techniques for harmonic and multiphoton absorption fluorescence microscopy

    PubMed Central

    Carriles, Ramón; Schafer, Dawn N.; Sheetz, Kraig E.; Field, Jeffrey J.; Cisek, Richard; Barzda, Virginijus; Sylvester, Anne W.; Squier, Jeffrey A.

    2009-01-01

    We review the current state of multiphoton microscopy. In particular, the requirements and limitations associated with high-speed multiphoton imaging are considered. A description of the different scanning technologies such as line scan, multifoci approaches, multidepth microscopy, and novel detection techniques is given. The main nonlinear optical contrast mechanisms employed in microscopy are reviewed, namely, multiphoton excitation fluorescence, second harmonic generation, and third harmonic generation. Techniques for optimizing these nonlinear mechanisms through a careful measurement of the spatial and temporal characteristics of the focal volume are discussed, and a brief summary of photobleaching effects is provided. Finally, we consider three new applications of multiphoton microscopy: nonlinear imaging in microfluidics as applied to chemical analysis and the use of two-photon absorption and self-phase modulation as contrast mechanisms applied to imaging problems in the medical sciences. PMID:19725639

  20. Optimal spectral filtering in soliton self-frequency shift for deep-tissue multiphoton microscopy

    NASA Astrophysics Data System (ADS)

    Wang, Ke; Qiu, Ping

    2015-05-01

    Tunable optical solitons generated by soliton self-frequency shift (SSFS) have become valuable tools for multiphoton microscopy (MPM). Recent progress in MPM using 1700 nm excitation enabled visualizing subcortical structures in mouse brain in vivo for the first time. Such an excitation source can be readily obtained by SSFS in a large effective-mode-area photonic crystal rod with a 1550-nm fiber femtosecond laser. A longpass filter was typically used to isolate the soliton from the residual in order to avoid excessive energy deposit on the sample, which ultimately leads to optical damage. However, since the soliton was not cleanly separated from the residual, the criterion for choosing the optimal filtering wavelength is lacking. Here, we propose maximizing the ratio between the multiphoton signal and the n'th power of the excitation pulse energy as a criterion for optimal spectral filtering in SSFS when the soliton shows dramatic overlapping with the residual. This optimization is based on the most efficient signal generation and entirely depends on physical quantities that can be easily measured experimentally. Its application to MPM may reduce tissue damage, while maintaining high signal levels for efficient deep penetration.

  1. Optimal spectral filtering in soliton self-frequency shift for deep-tissue multiphoton microscopy.

    PubMed

    Wang, Ke; Qiu, Ping

    2015-05-01

    Tunable optical solitons generated by soliton self-frequency shift (SSFS) have become valuable tools for multiphoton microscopy (MPM). Recent progress in MPM using 1700 nm excitation enabled visualizing subcortical structures in mouse brain in vivo for the first time. Such an excitation source can be readily obtained by SSFS in a large effective-mode-area photonic crystal rod with a 1550-nm fiber femtosecond laser. A longpass filter was typically used to isolate the soliton from the residual in order to avoid excessive energy deposit on the sample, which ultimately leads to optical damage. However, since the soliton was not cleanly separated from the residual, the criterion for choosing the optimal filtering wavelength is lacking. Here, we propose maximizing the ratio between the multiphoton signal and the n'th power of the excitation pulse energy as a criterion for optimal spectral filtering in SSFS when the soliton shows dramatic overlapping with the residual. This optimization is based on the most efficient signal generation and entirely depends on physical quantities that can be easily measured experimentally. Its application to MPM may reduce tissue damage, while maintaining high signal levels for efficient deep penetration. PMID:25950644

  2. Spectral imaging microscopy web sites and data.

    PubMed

    McNamara, George; Gupta, Amit; Reynaert, James; Coates, Thomas D; Boswell, Carl

    2006-08-01

    The Internet is enabling greater access to spectral imaging publications, spectral graphs, and data than that was available a generation ago. The spectral imaging systems discussed in this issue of Cytometry work because reagent and hardware spectra are reproducible, reusable, and provide input to spectral unmixing and spectral components recognition algorithms. These spectra need to be readily available in order to determine what to purchase, how to use it, and what the output means. We refer to several commercially sponsored and academic spectral web sites and discuss our spectral graphing and data sites. Sites include fluorescent dye graph servers from Invitrogen/Molecular Probes, BD Biosciences, Zeiss/Bio-Rad Cell Sciences, and filter set servers from Chroma Technology and Omega Optical. Several of these sites include data download capabilities. Recently, two microscope manufacturers have published on their web sites transmission curves for select objective lenses-crucial data for anyone doing multiphoton excitation microscopy. Notable among the academic sites, PhotoChemCAD 2.0 has over 200 dyes and a downloadable database/graphing program, and the USC-A Chemistry UV-vis Database displays absorption spectra of many dyes and indicators used in clinical histology and pathology. Our Fluorescent Spectra graphing/calculator site presents dyes, filters, and illumination data from many of these and additional sources. PubSpectra is our free download site which uses Microsoft Excel files as standardized human/machine readable format with over 2,000 biomedical spectra. The principle that data is not subject to copyright provides a framework in which all scientific data should be made freely accessible. PMID:16969821

  3. Multiphoton spectral analysis of benzo[a]pyrene uptake and metabolism in a rat liver cell line

    SciTech Connect

    Barhoumi, Rola; Mouneimne, Youssef; Ramos, Ernesto; Morisseau, Christophe; Hammock, Bruce D.; Safe, Stephen; Parrish, Alan R.; Burghardt, Robert C.

    2011-05-15

    Dynamic analysis of the uptake and metabolism of polycyclic aromatic hydrocarbons (PAHs) and their metabolites within live cells in real time has the potential to provide novel insights into genotoxic and non-genotoxic mechanisms of cellular injury caused by PAHs. The present work, combining the use of metabolite spectra generated from metabolite standards using multiphoton spectral analysis and an 'advanced unmixing process', identifies and quantifies the uptake, partitioning, and metabolite formation of one of the most important PAHs (benzo[a]pyrene, BaP) in viable cultured rat liver cells over a period of 24 h. The application of the advanced unmixing process resulted in the simultaneous identification of 8 metabolites in live cells at any single time. The accuracy of this unmixing process was verified using specific microsomal epoxide hydrolase inhibitors, glucuronidation and sulfation inhibitors as well as several mixtures of metabolite standards. Our findings prove that the two-photon microscopy imaging surpasses the conventional fluorescence imaging techniques and the unmixing process is a mathematical technique that seems applicable to the analysis of BaP metabolites in living cells especially for analysis of changes of the ultimate carcinogen benzo[a]pyrene-r-7,t-8-dihydrodiol-t-9,10-epoxide. Therefore, the combination of the two-photon acquisition with the unmixing process should provide important insights into the cellular and molecular mechanisms by which BaP and other PAHs alter cellular homeostasis.

  4. Two-photon imaging of intact living plants during freezing with a flexible multiphoton tomograph

    NASA Astrophysics Data System (ADS)

    Breunig, H. G.; König, K.

    2015-02-01

    We describe the combination of a flexible multiphoton tomograph (MPTflex) with a heating and cooling stage. The stage allows temperature control in the range of (-196 °C) (77 K) to +600 °C (873 K) with selectable heating/freezing rates between 0.01 K min-1 and 150 K min-1. To illustrate the imaging capabilities of the combined system, fluorescence intensity and lifetime of intrinsic molecules from a plant leaf were imaged with submicron resolution during freezing in vivo without detaching the leaf from the plant. An increase of fluorescence intensity and decay times with decreasing temperature was observed. The measurements illustrate the usefulness of multiphoton imaging as a non-invasive online tool to investigate temperature-induced effects. The flexible multiphoton tomograph with its adjustable mechano-optical arm and scan head allows imaging at otherwise hardly accessible sample regions.

  5. Real-time optical diagnosis of gastric cancer with serosal invasion using multiphoton imaging

    PubMed Central

    Yan, Jun; Zheng, Yu; Zheng, Xiaoling; Liu, Zhangyuanzhu; Liu, Wenju; Chen, Dexin; Dong, Xiaoyu; Li, Kai; Liu, Xiumin; Chen, Gang; Lu, Jianping; Chen, Jianxin; Zhuo, Shuangmu; Li, Guoxin

    2016-01-01

    A real-time optical biopsy, which could determine tissue histopathology, would be of extraordinary benefit to staging laparoscopy for gastric cancer with serosal invasion (T4) that requires downstage treatment. We investigated the feasibility of using multiphoton imaging to perform a real-time optical diagnosis of gastric cancer with or without serosal invasion. First, a pilot study was performed to establish the optical diagnostic features of gastric cancer with or without serosal invasion using multiphoton imaging compared with hematoxylin-eosin staining and Masson’s trichrome staining. Second, a blinded study was performed to compare the diagnostic sensitivity, specificity, and accuracy of multiphoton imaging and endoscopic ultrasonography (EUS) for T4 gastric cancer. In the pilot study, multiphoton imaging revealed collagen loss and degradation and cellular and nuclear pleomorphism in gastric cancer with serosal invasion. The collagen content in gastric cancer with or without serosal invasion was 0.36 ± 0.18 and 0.79 ± 0.16 (p < 0.001), respectively. In the blinded study, the sensitivity, specificity, and accuracy of EUS and multiphoton imaging for T4 gastric cancer were 70% and 90% (p = 0.029), 66.67% and 96.67% (p = 0.003), and 68.33% and 93.33% (p = 0.001), respectively. It is feasible to use multiphoton imaging to make a real-time optical diagnosis of gastric cancer with or without serosal invasion. PMID:27499365

  6. Label-free multiphoton imaging and photoablation of preinvasive cancer cells

    NASA Astrophysics Data System (ADS)

    Zhuo, Shuangmu; Chen, Jianxin; Wu, Guizhu; Zhu, Xiaoqin; Jiang, Xingshan; Xie, Shusen

    2012-01-01

    Detection and treatment of early lesions in epithelial tissue offer several possibilities for curing cancer, but it is challenging. Here, we present an optical technique, the combination of multiphoton imaging and absorption, to label-freely detect and ablate preinvasive cancer cells in epithelial tissue. We find that multiphoton imaging can label-freely visualize the principal features of nuclear atypia associated with epithelial precancerous lesions, and the spatial localization of multiphoton absorption can perform targeted ablation of preinvasive cancer cells with micrometer-sized volume precision. These results indicate that this optical technique has the capability to label-freely visualize and remove preinvasive cancer cells in epithelial tissue. This study highlights the potential of this technique as a "seek-and-treat" tool for early lesions in epithelial tissue.

  7. Multifocal multiphoton excitation and time correlated single photon counting detection for 3-D fluorescence lifetime imaging.

    PubMed

    Kumar, S; Dunsby, C; De Beule, P A A; Owen, D M; Anand, U; Lanigan, P M P; Benninger, R K P; Davis, D M; Neil, M A A; Anand, P; Benham, C; Naylor, A; French, P M W

    2007-10-01

    We report a multifocal multiphoton time-correlated single photon counting (TCSPC) fluorescence lifetime imaging (FLIM) microscope system that uses a 16 channel multi-anode PMT detector. Multiphoton excitation minimizes out-of-focus photobleaching, multifocal excitation reduces non-linear in-plane photobleaching effects and TCSPC electronics provide photon-efficient detection of the fluorescence decay profile. TCSPC detection is less prone to bleaching- and movement-induced artefacts compared to wide-field time-gated or frequency-domain FLIM. This microscope is therefore capable of acquiring 3-D FLIM images at significantly increased speeds compared to single beam multiphoton microscopy and we demonstrate this with live cells expressing a GFP tagged protein. We also apply this system to time-lapse FLIM of NAD(P)H autofluorescence in single live cells and report measurements on the change in the fluorescence decay profile following the application of a known metabolic inhibitor. PMID:19550524

  8. Imaging the bone marrow stem cells morphogenesis in PGA scaffold by multiphoton autofluorescence and second harmonic (SHG) imaging

    NASA Astrophysics Data System (ADS)

    Lee, Hsuan-Shu; Teng, Shu-Wen; Chen, Hsiao-Ching; Lo, Wen; Sun, Yen; Lin, Tze-Yu; Chiou, Ling-Ling; Jiang, Ching-Chuan; Dong, Chen-Yuan

    2006-02-01

    The ability to image tissue engineering products without damaging histological procedures is important for the understanding of the dynamics of tissue reorganization and formation. In this work, we test the ability of multiphoton autofluorescence and second harmonic generation microscopy to image engineered tissues following chrondrogenic induction. The system we used is human bone marrow stem cells seeded in the scaffold polyglycolic acid (PGA). Our results show that autofluorescence can be used to image cells while second harmonic generation signal can be used to visualize the synthesis of extracellular matrix. This approach demonstrates the ability of multiphoton imaging in the study of tissue engineering products.

  9. Biosensing and -imaging with enantiomeric luminescent conjugated polythiophenes using multiphoton excitation

    NASA Astrophysics Data System (ADS)

    Lindgren, Mikael; Stabo-Eeg, Frantz; Schnell, Edrun A.; Nilsson, K. Peter R.; Hammarstrom, Per; Inganaes, Olle

    2005-08-01

    We report on the initial time-resolved luminescense and nonlinear absorption properties of two polythiophenes 3-substituted with chiral charged amino acid-derivatized substituents, POWT and POMT. The photo-physical characterization yielded quantum efficiency typically in the range 0.01 - 0.1, however, with two-photon absorption cross-section better than or similar to a typical two-photon reference chromophore, such as fluorescein. They were tested as conformational sensitive optical probes for the recording of pH-induced conformational changes of synthetic peptides, proteins and samples of protein amyloid fibrils characteristic of amyloid related diseases. Particularly, the POMT polyelectrolyte with the L-enantiomeric side chains is shown to favor this induction of well defined structure as judged by the circular dichroic signal as well as a stronger enhancement of luminescense for the L-form over the D-form complex. Furthermore, time-resolved fluorescense and two-photon induced fluorescence both also showed a difference in the complexation with the D and L form. This shows that the multi-photon excitation path can be an efficient means for chiral recognition of biomolecular complexes. It is demonstrated how the conjugated polyelectrolyte L-POMT can be used to spectrally image the formation of amyloid fibrils of insulin using both one- and two-photon absorption based fluorescence imaging.

  10. Clinical combination of multiphoton tomography and high frequency ultrasound imaging for evaluation of skin diseases

    NASA Astrophysics Data System (ADS)

    König, K.; Speicher, M.; Koehler, M. J.; Scharenberg, R.; Elsner, P.; Kaatz, M.

    2010-02-01

    For the first time, high frequency ultrasound imaging, multiphoton tomography, and dermoscopy were combined in a clinical study. Different dermatoses such as benign and malign skin cancers, connective tissue diseases, inflammatory skin diseases and autoimmune bullous skin diseases have been investigated with (i) state-of-the-art and highly sophisticated ultrasound systems for dermatology, (ii) the femtosecond-laser multiphoton tomograph DermaInspectTM and (iii) dermoscopes. Dermoscopy provides two-dimensional color imaging of the skin surface with a magnification up to 70x. Ultrasound images are generated from reflections of the emitted ultrasound signal, based on inhomogeneities of the tissue. These echoes are converted to electrical signals. Depending on the ultrasound frequency the penetration depth varies from about 1 mm to 16 mm in dermatological application. The 100-MHz-ultrasound system provided an axial resolution down to 16 μm and a lateral resolution down to 32 μm. In contrast to the wide-field ultrasound images, multiphoton tomography provided horizontal optical sections of 0.36×0.36 mm2 down to 200 μm tissue depth with submicron resolution. The autofluorescence of mitochondrial coenzymes, melanin, and elastin as well as the secondharmonic- generation signal of the collagen network were imaged. The combination of ultrasound and multiphoton tomography provides a novel opportunity for diagnostics of skin disorders.

  11. Differentiation of normal and cancerous lung tissues by multiphoton imaging

    NASA Astrophysics Data System (ADS)

    Wang, Chun-Chin; Li, Feng-Chieh; Wu, Ruei-Jr; Hovhannisyan, Vladimir A.; Lin, Wei-Chou; Lin, Sung-Jan; So, Peter T. C.; Dong, Chen-Yuan

    2010-02-01

    In this work, we utilized multiphoton microscopy for the label-free diagnosis of non-cancerous, lung adenocarcinoma (LAC), and lung squamous cell carcinoma (SCC) tissues from human. Our results show that the combination of second harmonic generation (SHG) and multiphoton excited autofluorescence (MAF) signals may be used to acquire morphological and quantitative information in discriminating cancerous from non-cancerous lung tissues. Specifically, non-cancerous lung tissues are largely fibrotic in structure while cancerous specimens are composed primarily of tumor masses. Quantitative ratiometric analysis using MAF to SHG index (MAFSI or SAAID) shows that the average MAFSI for noncancerous and LAC lung tissue pairs are 0.55 +/-0.23 and 0.87+/-0.15 respectively. In comparison, the MAFSIs for the noncancerous and SCC tissue pairs are 0.50+/-0.12 and 0.72+/-0.13 respectively. Intrinsic fluorescence ratio (FAD/NADH) of SCC and non-cancerous tissues are 0.40+/-0.05 and 0.53+/-0.05 respectively, the redox ratio of SCC diminishes significantly, indicating that increased cellular metabolic activity. Our study shows that nonlinear optical microscopy can assist in differentiating and diagnosing pulmonary cancer from non-cancerous tissues. With additional development, multiphoton microscopy may be used for the clinical diagnosis of lung cancers.

  12. Stepwise multi-photon activation fluorescence reveals a new method of melanoma imaging for dermatologists

    NASA Astrophysics Data System (ADS)

    Lai, Zhenhua; Lian, Christine; Ma, Jie; Yu, Jingyi; Gu, Zetong; Rajadhyaksha, Milind; DiMarzio, Charles A.

    2014-02-01

    Previous research has shown that the stepwise multi-photon activated fluorescence (SMPAF) of melanin, activated by a continuous-wave (CW) mode near infrared (NIR) laser, is a low cost and reliable method of detecting melanin. SMPAF images of melanin in a mouse hair and a formalin fixed mouse melanoma were compared with conventional multiphoton fluorescence microscopy (MPFM) images and confocal reflectance microscopy (CRM) images, all of which were acquired at an excitation wavelength of 920 nm, to further prove the effectiveness of SMPAF in detecting melanin. SMPAF images add specificity for melanin detection to MPFM images and CRM images. Melanin SMPAF can be a promising technology to enable melanoma imaging for dermatologists.

  13. Clinical multiphoton FLIM tomography

    NASA Astrophysics Data System (ADS)

    König, Karsten

    2012-03-01

    This paper gives an overview on current clinical high resolution multiphoton fluorescence lifetime imaging in volunteers and patients. Fluorescence lifetime imaging (FLIM) in Life Sciences was introduced in Jena/Germany in 1988/89 based on a ZEISS confocal picosecond dye laser scanning microscope equipped with a single photon counting unit. The porphyrin distribution in living cells and living tumor-bearing mice was studied with high spatial, temporal, and spectral resolution. Ten years later, time-gated cameras were employed to detect dental caries in volunteers based on one-photon excitation of autofluorescent bacteria with long fluorescence lifetimes. Nowadays, one-photon FLIM based on picosecond VIS laser diodes are used to study ocular diseases in humans. Already one decade ago, first clinical twophoton FLIM images in humans were taken with the certified clinical multiphoton femtosecond laser tomograph DermaInspectTM. Multiphoton tomographs with FLIM modules are now operating in hospitals at Brisbane, Tokyo, Berlin, Paris, London, Modena and other European cities. Multiple FLIM detectors allow spectral FLIM with a temporal resolution down to 20 ps (MCP) / 250 ps (PMT) and a spectral resolution of 10 nm. Major FLIM applications include the detection of intradermal sunscreen and tattoo nanoparticles, the detection of different melanin types, the early diagnosis of dermatitis and malignant melanoma, as well as the measurement of therapeutic effects in pateints suffering from dermatitis. So far, more than 1,000 patients and volunteers have been investigated with the clinical multiphoton FLIM tomographs DermaInspectTM and MPTflexTM.

  14. A high speed multifocal multiphoton fluorescence lifetime imaging microscope for live-cell FRET imaging

    PubMed Central

    Poland, Simon P.; Krstajić, Nikola; Monypenny, James; Coelho, Simao; Tyndall, David; Walker, Richard J.; Devauges, Viviane; Richardson, Justin; Dutton, Neale; Barber, Paul; Li, David Day-Uei; Suhling, Klaus; Ng, Tony; Henderson, Robert K.; Ameer-Beg, Simon M.

    2015-01-01

    We demonstrate diffraction limited multiphoton imaging in a massively parallel, fully addressable time-resolved multi-beam multiphoton microscope capable of producing fluorescence lifetime images with sub-50ps temporal resolution. This imaging platform offers a significant improvement in acquisition speed over single-beam laser scanning FLIM by a factor of 64 without compromising in either the temporal or spatial resolutions of the system. We demonstrate FLIM acquisition at 500 ms with live cells expressing green fluorescent protein. The applicability of the technique to imaging protein-protein interactions in live cells is exemplified by observation of time-dependent FRET between the epidermal growth factor receptor (EGFR) and the adapter protein Grb2 following stimulation with the receptor ligand. Furthermore, ligand-dependent association of HER2-HER3 receptor tyrosine kinases was observed on a similar timescale and involved the internalisation and accumulation or receptor heterodimers within endosomes. These data demonstrate the broad applicability of this novel FLIM technique to the spatio-temporal dynamics of protein-protein interaction. PMID:25780724

  15. Label-free imaging and quantitative chemical analysis of Alzheimer's disease brain samples with multimodal multiphoton nonlinear optical microspectroscopy

    NASA Astrophysics Data System (ADS)

    Lee, Jang Hyuk; Kim, Dae Hwan; Song, Woo Keun; Oh, Myoung-Kyu; Ko, Do-Kyeong

    2015-05-01

    We developed multimodal multiphoton microspectroscopy using a small-diameter probe with gradient-index lenses and applied it to unstained Alzheimer's disease (AD) brain samples. Our system maintained the image quality and spatial resolution of images obtained using an objective lens of similar numerical aperture. Multicolor images of AD brain samples were obtained simultaneously by integrating two-photon excited fluorescence and second-harmonic generation on a coherent anti-Stokes Raman scattering (CARS) microendoscope platform. Measurements of two hippocampal regions, the cornus ammonis-1 and dentate gyrus, revealed more lipids, amyloid fibers, and collagen in the AD samples than in the normal samples. Normal and AD brains were clearly distinguished by a large spectral difference and quantitative analysis of the CH mode using CARS microendoscope spectroscopy. We expect this system to be an important diagnosis tool in AD research.

  16. Nanoparticle-assisted-multiphoton microscopy for in vivo brain imaging of mice

    NASA Astrophysics Data System (ADS)

    Qian, Jun

    2015-03-01

    Neuro/brain study has attracted much attention during past few years, and many optical methods have been utilized in order to obtain accurate and complete neural information inside the brain. Relying on simultaneous absorption of two or more near-infrared photons by a fluorophore, multiphoton microscopy can achieve deep tissue penetration and efficient light detection noninvasively, which makes it very suitable for thick-tissue and in vivo bioimaging. Nanoparticles possess many unique optical and chemical properties, such as anti-photobleaching, large multiphoton absorption cross-section, and high stability in biological environment, which facilitates their applications in long-term multiphoton microscopy as contrast agents. In this paper, we will introduce several typical nanoparticles (e.g. organic dye doped polymer nanoparticles and gold nanorods) with high multiphoton fluorescence efficiency. We further applied them in two- and three-photon in vivo functional brain imaging of mice, such as brain-microglia imaging, 3D architecture reconstruction of brain blood vessel, and blood velocity measurement.

  17. Enabling Multiphoton and Second Harmonic Generation Imaging in Paraffin-Embedded and Histologically Stained Sections

    PubMed Central

    Monaghan, Michael G.; Kroll, Sebastian; Brucker, Sara Y.

    2016-01-01

    Nonlinear microscopy, namely multiphoton imaging and second harmonic generation (SHG), is an established noninvasive technique useful for the imaging of extracellular matrix (ECM). Typically, measurements are performed in vivo on freshly excised tissues or biopsies. In this article, we describe the effect of rehydrating paraffin-embedded sections on multiphoton and SHG emission signals and the acquisition of nonlinear images from hematoxylin and eosin (H&E)-stained sections before and after a destaining protocol. Our results reveal that bringing tissue sections to a physiological state yields a significant improvement in nonlinear signals, particularly in SHG. Additionally, the destaining of sections previously processed with H&E staining significantly improves their SHG emission signals during imaging, thereby allowing sufficient analysis of collagen in these sections. These results are important for researchers and pathologists to obtain additional information from paraffin-embedded tissues and archived samples to perform retrospective analysis of the ECM or gain additional information from rare samples. PMID:27018844

  18. Multiphoton imaging of upconverting lanthanide nanoparticles in three dimensional models of cancer

    NASA Astrophysics Data System (ADS)

    Gainer, Christian F.; Romanowski, Marek

    2013-02-01

    While upconverting lanthanide nanoparticles have numerous advantages over other exogenous contrast agents used in scanned multiphoton imaging, their long luminescence lifetimes cause images collected with non-descanned detection to be greatly blurred. We demonstrate herein the use of Richardson-Lucy deconvolution to deblur luminescence images obtained via multiphoton scanning microscopy. Images were taken of three dimensional models of colon and ovarian cancer following incubation with NaYF4:Yb,Er nanoparticles functionalized with an antibody for EGFR and folic acid respectively. Following deconvolution, images had a lateral resolution on par with the optimal performance of the imaging system used, ~1.2 μm, and an axial resolution of ~5 μm. Due to the relatively high multiphoton excitation efficiency of these nanoparticles, it is possible to follow binding of individual particles in tissue. In addition, their extreme photostability allows for prolonged imaging without significant loss in luminescence signal. With these advantageous properties in mind, we also discuss the potential application of upconverting lanthanide nanoparticles for tracking of specific, cancer relevant receptors in tissue.

  19. Multiphoton Imaging of Upconverting Lanthanide Nanoparticles in Three Dimensional Models of Cancer

    PubMed Central

    Gainer, Christian F.; Romanowski, Marek

    2013-01-01

    While upconverting lanthanide nanoparticles have numerous advantages over other exogenous contrast agents used in scanned multiphoton imaging, their long luminescence lifetimes cause images collected with non-descanned detection to be greatly blurred. We demonstrate herein the use of Richardson-Lucy deconvolution to deblur luminescence images obtained via multiphoton scanning microscopy. Images were taken of three dimensional models of colon and ovarian cancer following incubation with NaYF4:Yb,Er nanoparticles functionalized with an antibody for EGFR and folic acid respectively. Following deconvolution, images had a lateral resolution on par with the optimal performance of the imaging system used, ~1.2 μm, and an axial resolution of ~5 μm. Due to the relatively high multiphoton excitation efficiency of these nanoparticles, it is possible to follow binding of individual particles in tissue. In addition, their extreme photostability allows for prolonged imaging without significant loss in luminescence signal. With these advantageous properties in mind, we also discuss the potential application of upconverting lanthanide nanoparticles for tracking of specific, cancer relevant receptors in tissue. PMID:24353385

  20. High-Resolution Mosaic Imaging with Multifocal, Multiphoton Photon-Counting Microscopy

    SciTech Connect

    Chandler, E.; Hoover, E.; Field, J.; Sheetz, K.; Amir, W.; Carriles, R.; Ding, S. Y.; Squier, J.

    2009-04-10

    High-resolution mosaic imaging is performed for the first time to our knowledge with a multifocal, multiphoton, photon-counting imaging system. We present a novel design consisting of a home-built femtosecond Yb-doped KGdWO{sub 4} laser with an optical multiplexer, which is coupled with a commercial Olympus IX-71 microscope frame. Photon counting is performed using single-element detectors and an inexpensive electronic demultiplexer and counters.

  1. ENVIRONMENTAL APPLICATIONS OF SPECTRAL IMAGING

    EPA Science Inventory

    The utility of remote sensing using spectral imaging is just being realized through the investigation to a wide variety of environmental issues. Improved spectral and spatial resolution is very important to the detection of effects once regarded as unobservable. A current researc...

  2. In vivo stepwise multi-photon activation fluorescence imaging of melanin in human skin

    NASA Astrophysics Data System (ADS)

    Lai, Zhenhua; Gu, Zetong; Abbas, Saleh; Lowe, Jared; Sierra, Heidy; Rajadhyaksha, Milind; DiMarzio, Charles

    2014-03-01

    The stepwise multi-photon activated fluorescence (SMPAF) of melanin is a low cost and reliable method of detecting melanin because the activation and excitation can be a continuous-wave (CW) mode near infrared (NIR) laser. Our previous work has demonstrated the melanin SMPAF images in sepia melanin, mouse hair, and mouse skin. In this study, we show the feasibility of using SMPAF to detect melanin in vivo. in vivo melanin SMPAF images of normal skin and benign nevus are demonstrated. SMPAF images add specificity for melanin detection than MPFM images and CRM images. Melanin SMPAF is a promising technology to enable early detection of melanoma for dermatologists.

  3. Spectral imaging using forward-viewing spectrally encoded endoscopy

    PubMed Central

    Zeidan, Adel; Yelin, Dvir

    2016-01-01

    Spectrally encoded endoscopy (SEE) enables miniature, small-diameter endoscopic probes for minimally invasive imaging; however, using the broadband spectrum to encode space makes color and spectral imaging nontrivial and challenging. By careful registration and analysis of image data acquired by a prototype of a forward-viewing dual channel spectrally encoded rigid probe, we demonstrate spectral and color imaging within a narrow cylindrical lumen. Spectral imaging of calibration cylindrical test targets and an ex-vivo blood vessel demonstrates high-resolution spatial-spectral imaging with short (10 μs/line) exposure times. PMID:26977348

  4. Spectral imaging using forward-viewing spectrally encoded endoscopy.

    PubMed

    Zeidan, Adel; Yelin, Dvir

    2016-02-01

    Spectrally encoded endoscopy (SEE) enables miniature, small-diameter endoscopic probes for minimally invasive imaging; however, using the broadband spectrum to encode space makes color and spectral imaging nontrivial and challenging. By careful registration and analysis of image data acquired by a prototype of a forward-viewing dual channel spectrally encoded rigid probe, we demonstrate spectral and color imaging within a narrow cylindrical lumen. Spectral imaging of calibration cylindrical test targets and an ex-vivo blood vessel demonstrates high-resolution spatial-spectral imaging with short (10 μs/line) exposure times. PMID:26977348

  5. Rayleigh imaging in spectral mammography

    NASA Astrophysics Data System (ADS)

    Berggren, Karl; Danielsson, Mats; Fredenberg, Erik

    2016-03-01

    Spectral imaging is the acquisition of multiple images of an object at different energy spectra. In mammography, dual-energy imaging (spectral imaging with two energy levels) has been investigated for several applications, in particular material decomposition, which allows for quantitative analysis of breast composition and quantitative contrast-enhanced imaging. Material decomposition with dual-energy imaging is based on the assumption that there are two dominant photon interaction effects that determine linear attenuation: the photoelectric effect and Compton scattering. This assumption limits the number of basis materials, i.e. the number of materials that are possible to differentiate between, to two. However, Rayleigh scattering may account for more than 10% of the linear attenuation in the mammography energy range. In this work, we show that a modified version of a scanning multi-slit spectral photon-counting mammography system is able to acquire three images at different spectra and can be used for triple-energy imaging. We further show that triple-energy imaging in combination with the efficient scatter rejection of the system enables measurement of Rayleigh scattering, which adds an additional energy dependency to the linear attenuation and enables material decomposition with three basis materials. Three available basis materials have the potential to improve virtually all applications of spectral imaging.

  6. Using multiphoton fluorescence lifetime imaging to characterize liver damage and fluorescein disposition in liver in vivo

    NASA Astrophysics Data System (ADS)

    Thorling, Camilla A.; Studier, Hauke; Crawford, Darrell; Roberts, Michael S.

    2016-03-01

    Liver disease is the fifth most common cause of death and unlike many other major causes of mortality, liver disease rates are increasing rather than decreasing. There is no ideal measurement of liver disease and although biopsies are the gold standard, this only allows for a spot examination and cannot follow dynamic processes of the liver. Intravital imaging has the potential to extract detailed information over a larger sampling area continuously. The aim of this project was to investigate whether multiphoton and fluorescence lifetime imaging microscopy could detect early liver damage and to assess whether it could detect changes in metabolism of fluorescein in normal and diseased livers. Four experimental groups were used in this study: 1) control; 2) ischemia reperfusion injury; 3) steatosis and 4) steatosis with ischemia reperfusion injury. Results showed that multiphoton microscopy could visualize morphological changes such as decreased fluorescence of endogenous fluorophores and the presence of lipid droplets, characteristic of steatosis. Fluorescence lifetime imaging microscopy showed increase in NADPH in steatosis with and without ischemia reperfusion injury and could detect changes in metabolism of fluorescein to fluorescein monoglurcuronide, which was impaired in steatosis with ischemia reperfusion injury. These results concluded that the combination of multiphoton microscopy and fluorescence lifetime imaging is a promising method of assessing early stage liver damage and that it can be used to study changes in drug metabolism in the liver as an indication of liver disease and has the potential to replace the traditional static liver biopsy currently used.

  7. In vitro imaging of embryonic stem cells using multiphoton luminescence of gold nanoparticles

    PubMed Central

    Nagesha, D; Laevsky, GS; Lampton, P; Banyal, R; Warner, C; DiMarzio, C; Sridhar, S

    2007-01-01

    Recent advances in nonlinear optical techniques and materials such as quantum wells, nanowires and noble-metal nanoparticles have led to advances in cellular imaging wherein various nanoparticles have been shown to improve both in vitro and in vivo visualization. In this paper, we demonstrate in vitro imaging using multi-photon photoluminescence of gold nanoparticles from two different cell types – Dictyostelium discoideum and mouse embryonic stem cells. By observing nanoparticles we show that embryonic stem cells maintained their ability to proliferate for several passages while grown in the presence of gold nanoparticles. The advantages of multi-photon luminescence using gold nanoparticles have important implications for use in stem cell proliferation experiments and in vitro experiments to monitor differentiation. PMID:18203448

  8. In vivo imaging of unstained tissues using long gradient index lens multiphoton endoscopic systems.

    PubMed

    Huland, David M; Brown, Christopher M; Howard, Scott S; Ouzounov, Dimitre G; Pavlova, Ina; Wang, Ke; Rivera, David R; Webb, Watt W; Xu, Chris

    2012-05-01

    We characterize long (up to 285 mm) gradient index (GRIN) lens endoscope systems for multiphoton imaging. We fabricate a portable, rigid endoscope system suitable for imaging unstained tissues, potentially deep within the body, using a GRIN lens system of 1 mm diameter and 8 cm length. The portable device is capable of imaging a ~200 µm diameter field of view at 4 frames/s. The lateral and axial resolution in water is 0.85 µm and 7.4 µm respectively. In vivo images of unstained tissues in live, anesthetized rats using the portable device are presented. These results show great promise for GRIN endoscopy to be used clinically. PMID:22567597

  9. SPECTRAL IMAGING TECHNIQUES FOR GRAIN

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Three spectral imaging techniques were employed for the purpose of assessing the quality of cereal grains. Each of these techniques provided unique, yet complementary, information. Nuclear magnetic resonance (NMR), also called magnetic resonance imaging (MRI), was used to detect mobile components ...

  10. Compact fixed wavelength femtosecond oscillators for multi-photon imaging

    NASA Astrophysics Data System (ADS)

    Hakulinen, T.; Klein, J.; Zadoyan, R.; Baldacchini, T.; Franke, T.

    2015-03-01

    In recent years two-photon microscopy with fixed-wavelength has raised increasing interest in life-sciences: Two-photon (2P) absorption spectra of common dyes are broader than single-photon ones. Therefore, excitation of several dyes simultaneously with a single IR laser wavelength is feasible and could be seen as an advantage in 2P microscopy. We used pulsed fixed-wavelength infrared lasers with center wavelength at 1040 nm, for two-photon microscopy in a variety of biologically relevant samples, among these a mouse brain sample, a mouse artery (within the animal, acute preparation), and a preparation of mouse bladder. The 1040 nm laser proved to be efficient not only in exciting fluorescence from yellow fluorescent protein (YFP) and red fluorescent dyes, but also for second harmonic generation (SHG) signals from muscle tissue and collagen. With this work we demonstrate that economical, small-footprint fixedwavelength lasers can present an interesting alternative to tunable lasers that are commonly used in multiphoton microscopy.

  11. Multiphoton fluorescence imaging of NADH to quantify metabolic changes in epileptic tissue in vitro

    NASA Astrophysics Data System (ADS)

    Chia, Thomas H.; Zinter, Joseph; Spencer, Dennis D.; Williamson, Anne; Levene, Michael J.

    2007-02-01

    A powerful advantage of multiphoton microscopy is its ability to image endogenous fluorophores such as the ubiquitous coenzyme NADH in discrete cellular populations. NADH is integral in both oxidative and non-oxidative cellular metabolism. NADH loses fluorescence upon oxidation to NAD +; thus changes in NADH fluorescence can be used to monitor metabolism. Recent studies have suggested that hypo metabolic astrocytes play an important role in cases of temporal lobe epilepsy (TLE). Current theories suggest this may be due to defective and/or a reduced number of mitochondria or dysfunction of the neuronal-astrocytic metabolic coupling. Measuring NADH fluorescence changes following chemical stimulation enables the quantification of the cellular distribution of metabolic anomalies in epileptic brain tissue compared to healthy tissue. We present what we believe to be the first multiphoton microscopy images of NADH from the human brain. We also present images of NADH fluorescence from the hippocampus of the kainate-treated rat TLE model. In some experiments, human and rat astrocytes were selectively labeled with the fluorescent dye sulforhodamine 101 (SR101). Our results demonstrate that multiphoton microscopy is a powerful tool for assaying the metabolic pathologies associated with temporal lobe epilepsy in humans and in rodent models.

  12. Onboard spectral imager data processor

    NASA Astrophysics Data System (ADS)

    Otten, Leonard J.; Meigs, Andrew D.; Franklin, Abraham J.; Sears, Robert D.; Robison, Mark W.; Rafert, J. Bruce; Fronterhouse, Donald C.; Grotbeck, Ronald L.

    1999-10-01

    Previous papers have described the concept behind the MightySat II.1 program, the satellite's Fourier Transform imaging spectrometer's optical design, the design for the spectral imaging payload, and its initial qualification testing. This paper discusses the on board data processing designed to reduce the amount of downloaded data by an order of magnitude and provide a demonstration of a smart spaceborne spectral imaging sensor. Two custom components, a spectral imager interface 6U VME card that moves data at over 30 MByte/sec, and four TI C-40 processors mounted to a second 6U VME and daughter card, are used to adapt the sensor to the spacecraft and provide the necessary high speed processing. A system architecture that offers both on board real time image processing and high-speed post data collection analysis of the spectral data has been developed. In addition to the on board processing of the raw data into a usable spectral data volume, one feature extraction technique has been incorporated. This algorithm operates on the basic interferometric data. The algorithm is integrated within the data compression process to search for uploadable feature descriptions.

  13. In vivo multiphoton imaging of collagen remodeling after microablative fractional rejuvenation

    NASA Astrophysics Data System (ADS)

    Cicchi, Riccardo; Kapsokalyvas, Dimitrios; Troiano, Michela; Campolmi, Piero; Morini, Cristiano; Cosci, Alessandro; Massi, Daniela; Lotti, Torello; Pavone, Francesco S.

    2011-03-01

    The potential of multiphoton microscopy in providing in-vivo early diagnosis of skin lesions has already been demonstrated, while its capability in therapy follow-up has not been deeply explored so far. Two-photon excited fluorescence and second-harmonic generation microscopy were used in combination to follow-up collagen remodeling after laser micro-ablative rejuvenation. Treated regions of volunteers were imaged with multiphoton microscopy before and after treatment, and we found a strong age-dependence of the treatment effectiveness. In particular, the photorejuvenating effect was negligible in young subjects (< 30 years), whereas a significant production of new collagen was observed in aged subjects (> 70 years). Quantification of the amount of newly produced collagen and its organization were performed by means of visual examination of two-photon images. The obtained results demonstrate the performance of laser fractional micro-ablative rejuvenation without the need of an invasive biopsy as well as the wide applicability range of applications for multiphoton microscopy in clinical dermatology.

  14. Eliminating the scattering ambiguity in multifocal, multimodal multiphoton imaging systems

    PubMed Central

    Hoover, Erich E.; Field, Jeffrey J.; Winters, David G.; Young, Michael D.; Chandler, Eric V.; Speirs, John C.; Kim, Susy M.; Ding, Shi-you; Bartels, Randy A.; Wang, Jing W.; Squier, Jeff A.

    2013-01-01

    Four images of Drosophila Melanogaster antennal lobe structure labeled with red fluorescent protein. The images are separated axially by 7 μm in depth, and were all acquired simultaneously from a single-element detector. PMID:22461190

  15. Snapshot colored compressive spectral imager.

    PubMed

    Correa, Claudia V; Arguello, Henry; Arce, Gonzalo R

    2015-10-01

    Traditional spectral imaging approaches require sensing all the voxels of a scene. Colored mosaic FPA detector-based architectures can acquire sets of the scene's spectral components, but the number of spectral planes depends directly on the number of available filters used on the FPA, which leads to reduced spatiospectral resolutions. Instead of sensing all the voxels of the scene, compressive spectral imaging (CSI) captures coded and dispersed projections of the spatiospectral source. This approach mitigates the resolution issues by exploiting optical phenomena in lenses and other elements, which, in turn, compromise the portability of the devices. This paper presents a compact snapshot colored compressive spectral imager (SCCSI) that exploits the benefits of the colored mosaic FPA detectors and the compression capabilities of CSI sensing techniques. The proposed optical architecture has no moving parts and can capture the spatiospectral information of a scene in a single snapshot by using a dispersive element and a color-patterned detector. The optical and the mathematical models of SCCSI are presented along with a testbed implementation of the system. Simulations and real experiments show the accuracy of SCCSI and compare the reconstructions with those of similar CSI optical architectures, such as the CASSI and SSCSI systems, resulting in improvements of up to 6 dB and 1 dB of PSNR, respectively. PMID:26479928

  16. Imaging NO elimination in the infrared multiphoton dissociation of nitroalkanes and alkyl nitrites

    NASA Astrophysics Data System (ADS)

    Fernando, Ravin; Ariyasingha, Nuwandi M.; Suits, Arthur G.

    2016-02-01

    We present a DC slice imaging study of the decomposition of C2, C3 and C4 nitroalkanes and alkyl nitrites, focusing on the NO elimination channel, possibly a minor pathway. Infrared multiphoton dissociation (IRMPD) is used to induce dissociation on the ground electronic state under collisionless conditions. The channels that produced NO as a product were studied and compared among the target molecules to gain a better understanding of the isomerization of the nitroalkanes prior to dissociation. Trends in the total translational energy and NO rotational temperatures obtained from the images are discussed.

  17. Fast volumetric imaging with patterned illumination via digital micro-mirror device-based temporal focusing multiphoton microscopy

    PubMed Central

    Chang, Chia-Yuan; Hu, Yvonne Yuling; Lin, Chun-Yu; Lin, Cheng-Han; Chang, Hsin-Yu; Tsai, Sheng-Feng; Lin, Tzu-Wei; Chen, Shean-Jen

    2016-01-01

    Temporal focusing multiphoton microscopy (TFMPM) has the advantage of area excitation in an axial confinement of only a few microns; hence, it can offer fast three-dimensional (3D) multiphoton imaging. Herein, fast volumetric imaging via a developed digital micromirror device (DMD)-based TFMPM has been realized through the synchronization of an electron multiplying charge-coupled device (EMCCD) with a dynamic piezoelectric stage for axial scanning. The volumetric imaging rate can achieve 30 volumes per second according to the EMCCD frame rate of more than 400 frames per second, which allows for the 3D Brownian motion of one-micron fluorescent beads to be spatially observed. Furthermore, it is demonstrated that the dynamic HiLo structural multiphoton microscope can reject background noise by way of the fast volumetric imaging with high-speed DMD patterned illumination. PMID:27231617

  18. Fast volumetric imaging with patterned illumination via digital micro-mirror device-based temporal focusing multiphoton microscopy.

    PubMed

    Chang, Chia-Yuan; Hu, Yvonne Yuling; Lin, Chun-Yu; Lin, Cheng-Han; Chang, Hsin-Yu; Tsai, Sheng-Feng; Lin, Tzu-Wei; Chen, Shean-Jen

    2016-05-01

    Temporal focusing multiphoton microscopy (TFMPM) has the advantage of area excitation in an axial confinement of only a few microns; hence, it can offer fast three-dimensional (3D) multiphoton imaging. Herein, fast volumetric imaging via a developed digital micromirror device (DMD)-based TFMPM has been realized through the synchronization of an electron multiplying charge-coupled device (EMCCD) with a dynamic piezoelectric stage for axial scanning. The volumetric imaging rate can achieve 30 volumes per second according to the EMCCD frame rate of more than 400 frames per second, which allows for the 3D Brownian motion of one-micron fluorescent beads to be spatially observed. Furthermore, it is demonstrated that the dynamic HiLo structural multiphoton microscope can reject background noise by way of the fast volumetric imaging with high-speed DMD patterned illumination. PMID:27231617

  19. Optimizing ultrafast illumination for multiphoton-excited fluorescence imaging.

    PubMed

    Stoltzfus, Caleb R; Rebane, Aleksander

    2016-05-01

    We study the optimal conditions for high throughput two-photon excited fluorescence (2PEF) and three-photon excited fluorescence (3PEF) imaging using femtosecond lasers. We derive relations that allow maximization of the rate of imaging depending on the average power, pulse repetition rate, and noise characteristics of the laser, as well as on the size and structure of the sample. We perform our analysis using ~100 MHz, ~1 MHz and 1 kHz pulse rates and using both a tightly-focused illumination beam with diffraction-limited image resolution, as well loosely focused illumination with a relatively low image resolution, where the latter utilizes separate illumination and fluorescence detection beam paths. Our theoretical estimates agree with the experiments, which makes our approach especially useful for optimizing high throughput imaging of large samples with a field-of-view up to 10x10 cm(2). PMID:27231620

  20. Optimizing ultrafast illumination for multiphoton-excited fluorescence imaging

    PubMed Central

    Stoltzfus, Caleb R.; Rebane, Aleksander

    2016-01-01

    We study the optimal conditions for high throughput two-photon excited fluorescence (2PEF) and three-photon excited fluorescence (3PEF) imaging using femtosecond lasers. We derive relations that allow maximization of the rate of imaging depending on the average power, pulse repetition rate, and noise characteristics of the laser, as well as on the size and structure of the sample. We perform our analysis using ~100 MHz, ~1 MHz and 1 kHz pulse rates and using both a tightly-focused illumination beam with diffraction-limited image resolution, as well loosely focused illumination with a relatively low image resolution, where the latter utilizes separate illumination and fluorescence detection beam paths. Our theoretical estimates agree with the experiments, which makes our approach especially useful for optimizing high throughput imaging of large samples with a field-of-view up to 10x10 cm2. PMID:27231620

  1. Multiphoton imaging of excised normal skin and keloid scar: preliminary investigations

    NASA Astrophysics Data System (ADS)

    Brewer, Michael B.; Yeh, Alvin T.; Torkian, Behrooz; Sun, Chung-Ho; Tromberg, Bruce J.; Wong, Brian J.

    2004-07-01

    Wound healing is a physiologic process that acts to repair disruptions in the continuity of tissue caused by injury or surgical incision. Keloids and hypertrophic scars are forms of aberrant wound healing, which are characterized by the overproduction of collagen, resulting in an excessive amount of scar tissue. Keloid tumors, by definition, grow outside the boundary of the original tissue damage. Multiphoton microscopy (MPM) is an imaging technique which allows imaging of living specimens, without the use of fixation or stains. Images of collagen fibers are produced by the second harmonic signal intensity generated by endogenous fluorescence through excitation by infrared laser light. A postauricular keloid tumor was excised from a patient. The tissue was dissected, and a portion was imaged using MPM. Normal skin tissue was isolated from a patient undergoing a facelift. A portion of this tissue was also dissected and imaged using MPM. MPM images were taken using a 63X water immersion objective lens on a two-photon microscope and a titanium-sapphire laser. Images were taken beginning at the surface of the tissue and moving in at intervals of 200 nm to a final depth of 30 μm. The two-photon images were used to reconstruct three-dimensional representations of the collagen matrix within the tissues, which are readily contrasted. Density of the collagen within each tissue was also ascertained using depth dependant decay of the image intensity. Multiphoton imaging was successfully used to image the collagen matrix of normal skin and a keloid scar, demonstrating differences in their microstructures.

  2. Quantitative characterization of articular cartilage using Mueller matrix imaging and multiphoton microscopy

    NASA Astrophysics Data System (ADS)

    Ellingsen, Pa˚L. Gunnar; Lilledahl, Magnus Borstad; Aas, Lars Martin Sandvik; Davies, Catharina De Lange; Kildemo, Morten

    2011-11-01

    The collagen meshwork in articular cartilage of chicken knee is characterized using Mueller matrix imaging and multiphoton microscopy. Direction and degree of dispersion of the collagen fibers in the superficial layer are found using a Fourier transform image-analysis technique of the second-harmonic generated image. Mueller matrix images are used to acquire structural data from the intermediate layer of articular cartilage where the collagen fibers are too small to be resolved by optical microscopy, providing a powerful multimodal measurement technique. Furthermore, we show that Mueller matrix imaging provides more information about the tissue compared to standard polarization microscopy. The combination of these techniques can find use in improved diagnosis of diseases in articular cartilage, improved histopathology, and additional information for accurate biomechanical modeling of cartilage.

  3. THREE-DIMENSIONAL RANDOM ACCESS MULTIPHOTON MICROSCOPY FOR FAST FUNCTIONAL IMAGING OF NEURONAL ACTIVITY

    PubMed Central

    Reddy, Gaddum Duemani; Kelleher, Keith; Fink, Rudy; Saggau, Peter

    2009-01-01

    The dynamic ability of neuronal dendrites to shape and integrate synaptic responses is the hallmark of information processing in the brain. Effectively studying this phenomenon requires concurrent measurements at multiple sites on live neurons. Significant progress has been made by optical imaging systems which combine confocal and multiphoton microscopy with inertia-free laser scanning. However, all systems developed to date restrict fast imaging to two dimensions. This severely limits the extent to which neurons can be studied, since they represent complex three-dimensional (3D) structures. Here we present a novel imaging system that utilizes a unique arrangement of acousto-optic deflectors to steer a focused ultra-fast laser beam to arbitrary locations in 3D space without moving the objective lens. As we demonstrate, this highly versatile random-access multiphoton microscope supports functional imaging of complex 3D cellular structures such as neuronal dendrites or neural populations at acquisition rates on the order of tens of kilohertz. PMID:18432198

  4. Characterization of multiphoton photoacoustic spectroscopy for subsurface brain tissue diagnosis and imaging

    NASA Astrophysics Data System (ADS)

    Dahal, Sudhir; Cullum, Brian M.

    2016-04-01

    The development and demonstration of a multiphoton photoacoustic imaging technique capable of providing high spatial resolution chemical images of subsurface tissue components as deep as 1.4 cm below the tissue surface is described. By combining multiphoton excitation in the diagnostic window (650 to 1100 nm), with ultrasonic detection of nonradiative relaxation events, it is possible to rapidly reconstruct three-dimensional, chemical specific, images of samples underneath overlying structures as well as chemical species of the same material. Demonstration of this technique for subsurface tissue differentiation is shown, with the ability to distinguish between grade III astrocytoma tissue and adjacent healthy tissue in blind studies. By employing photoacoustic signal detection, the high nonradiative relaxation rates of most biological tissue components (>90%) and the minimal signal attenuation of the resulting ultrasound compensate for excitation efficiency losses associated with two-photon absorption. Furthermore, the two-photon absorption process results in a highly localized excitation volume (ca., 60 μm). Characterization of the probing depth, spatial resolution, and ability to image through overlying structures is also demonstrated in this paper using tissue phantoms with well-characterized optical scattering properties, mimicking those of tissues.

  5. Long-term marker-free multiphoton imaging, targeted transfection, optical cleaning of stem cell clusters, and optical transport of microRNA with extreme ultrashort laser pulses

    NASA Astrophysics Data System (ADS)

    Uchugonova, Aisada; Földes-Papp, Zeno; Kostner, Gerhard M.; König, Karsten

    2010-02-01

    The novel utrashort femtosecond laser scanning microscope FemtOgene (JenLab GmbH, Germany) with 12 femtoseconds at the focal plane have been employed in marker-free imaging and optical manipulation of stem cells as well as for the non-contact introduction of microRNA in cancer cells. Human adult pancreatic stem cells, salivary gland stem cells, and human dental pulp stem cells have been investigated by femtosecond laser multiphoton microscopy. Autofluorescence based on NAD(P)H and flavoproteins and second harmonic generation due to collagen have been imaged with submicron spatial resolution, 270 ps temporal resolution, and 10 nm spectral resolution. Major emission peaks at 460 nm and 530 nm with typical mean fluorescence lifetimes of 1.8 ns and 2.0 ns, respectively, were measured in a variety of stem cells using spectral imaging and time-correlated single photon counting. During differentiation, the ratios of bound to free NAD(P)H and NAD(P)H/flavoproteins changed. In addition, the biosynthesis of lipids and collagen was detected over a long period of time of up to 5 weeks. Nanoprocessing was performed with 12 femtosecond laser pulses and low picojoule pulse energies to realize targeted transfection and optical cleaning of human adult stem cell populations. Multiphoton sub-20fs microscopes may become novel non-invasive tools for marker-free optical stem cell characterization, for on-line monitoring of differentiation within a three-dimensional microenvironment, and for optical manipulation.

  6. Multiphoton imaging approaches for studying striatal dendritic excitability.

    PubMed

    Plotkin, Joshua L; Surmeier, D James

    2014-01-01

    As the main input nucleus to the basal ganglia, the striatum is responsible for receiving and integrating highly convergent afferents to ultimately guide action selection and movement initiation. Although the majority of this synaptic integration occurs in the dendrites of striatal projection neurons (SPNs), their thin diameter makes them inaccessible with traditional recording electrodes. Recent advances in optical imaging technologies have allowed us and others to start lifting the veil on the mechanisms governing synaptic integration in the striatum by enabling direct dendritic measurements and manipulations. Here we describe how our lab has approached combining 2-photon imaging and photolysis with electrophysiological recordings to study dendritic excitability and synaptic integration in the striatum. PMID:25023308

  7. Chronic imaging of amyloid plaques in the live mouse brain using multiphoton microscopy

    NASA Astrophysics Data System (ADS)

    Bacskai, Brian J.; Kajdasz, Stephen T.; Christie, R. H.; Zipfel, Warren R.; Williams, Rebecca M.; Kasischke, Karl A.; Webb, Watt W.; Hyman, B. T.

    2001-04-01

    Transgenic mice expressing the human Amyloid Precursor Protein (APP) develop amyloid plaques as they age. These plaques resemble those found in the human disease. Multiphoton laser scanning microscopy combined with a novel surgical approach was used to measure amyloid plaque dynamics chronically in the cortex of living transgenic mice. Thioflavine S (thioS) was used as a fluorescent marker of amyloid deposits. Multiphoton excitation allowed visualization of amyloid plaques up to 200 micrometers deep into the brain. The surgical site could be imaged repeatedly without overt damage to the tissue, and individual plaques within this volume could be reliably identified over periods of several days to several months. On average, plaque sizes remained constant over time, supporting a model of rapid deposition, followed by relative stability. Alternative reporters for in vivo histology include thiazine red, and FITC-labeled amyloid-(Beta) peptide. We also present examples of multi-color imaging using Hoechst dyes and FITC-labeled tomato lectin. These approaches allow us to observe cell nuclei or microglia simultaneously with amyloid-(Beta) deposits in vivo. Chronic imaging of a variety of reporters in these transgenic mice should provide insight into the dynamics of amyloid-(Beta) activity in the brain.

  8. Setup and use of a two-laser multiphoton microscope for multichannel intravital fluorescence imaging

    PubMed Central

    Entenberg, David; Wyckoff, Jeffrey; Gligorijevic, Bojana; Roussos, Evanthia T; Verkhusha, Vladislav V; Pollard, Jeffrey W; Condeelis, John

    2014-01-01

    Characterizing biological mechanisms dependent upon the interaction of many cell types in vivo requires both multiphoton microscope systems capable of expanding the number and types of fluorophores that can be imaged simultaneously while removing the wavelength and tunability restrictions of existing systems, and enhanced software for extracting critical cellular parameters from voluminous 4D data sets. We present a procedure for constructing a two-laser multiphoton microscope that extends the wavelength range of excitation light, expands the number of simultaneously usable fluorophores and markedly increases signal to noise via ‘over-clocking’ of detection. We also utilize a custom-written software plug-in that simplifies the quantitative tracking and analysis of 4D intravital image data. We begin by describing the optics, hardware, electronics and software required, and finally the use of the plug-in for analysis. We demonstrate the use of the setup and plug-in by presenting data collected via intravital imaging of a mouse model of breast cancer. The procedure may be completed in ~24 h. PMID:21959234

  9. Imaging sulfur mustard lesions in human epidermal tissues and keratinocytes by confocal and multiphoton microscopy

    NASA Astrophysics Data System (ADS)

    Werrlein, Robert; Madren-Whalley, Janna S.

    2002-06-01

    Topical exposure to sulfur mustard (HD), a known theat agent, produces persistent and debilitating cutaneous blisters. The blisters occur at the dermal-epidermal junction following a dose-dependent latent period of 8-24 h, however, the primary lesions causing vesication remain uncertain. Immunofluorescent images reveal that a 5-min exposure to 400 (mu) M HD disrupts molecules that are also disrupted by epidermolysis bullosa-type blistering diseases of the skin. Using keratinocyte cultures and fluorochomes conjugated to two different keratin-14 (K14) antibodies (clones CKB1 and LL002), results have shown a statistically significant (p<0.1) 1-h decrease of 29.2% in expression of the CKB1 epitope, a nearly complete loss of CKB1 expression within 2 h, and progressive cytoskeletal (K14) collapse without loss in expression of the LL002 epitope. With human epidermal tissues, multi-photon images of (alpha) 6 integrin and laminin 5 showed disruptive changes in the cell-surface organization and integrity of these adhesion molecules. At 1 H postexposure, analyses showed a statistically significant (p<0.1) decrease of 27.3% in (alpha) 6 integrin emissions, and a 32% decrease in laminin 5 volume. Multi-photon imaging indicates that molecules essential for epidermal-dermal attachment are early targets in the alkylating events leading to HD-induced vesication.

  10. In vivo imaging of spinal cord in contusion injury model mice by multi-photon microscopy

    NASA Astrophysics Data System (ADS)

    Oshima, Y.; Horiuchi, H.; Ogata, T.; Hikita, A.; Miura, H.; Imamura, T.

    2014-03-01

    Fluorescent imaging technique is a promising method and has been developed for in vivo applications in cellular biology. In particular, nonlinear optical imaging technique, multi-photon microscopy has make it possible to analyze deep portion of tissues in living animals such as axons of spinal code. Traumatic spinal cord injuries (SCIs) are usually caused by contusion damages. Therefore, observation of spinal cord tissue after the contusion injury is necessary for understanding cellular dynamics in response to traumatic SCI and development of the treatment for traumatic SCI. Our goal is elucidation of mechanism for degeneration of axons after contusion injuries by establishing SCI model and chronic observation of injured axons in the living animals. Firstly we generated and observed acute SCI model by contusion injury. By using a multi-photon microscope, axons in dorsal cord were visualized approximately 140 micron in depth from the surface. Immediately after injury, minimal morphological change of spinal cord was observed. At 3 days after injury, spinal cord was swelling and the axons seem to be fragmented. At 7 days after injury, increased degradation of axons could be observed, although the image was blurred due to accumulation of the connective tissue. In the present study, we successfully observed axon degeneration after the contusion SCI in a living animal in vivo. Our final goal is to understand molecular mechanisms and cellular dynamics in response to traumatic SCIs in acute and chronic stage.

  11. Real-time histological imaging of kidneys stained with food dyes using multiphoton microscopy.

    PubMed

    Nagao, Yasuaki; Kimura, Kazushi; Wang, Shujie; Fujiwara, Takeshi; Mizoguchi, Akira

    2015-10-01

    We have developed a real-time imaging technique for diagnosis of kidney diseases which is composed of two steps, staining renal cells safely with food dyes and optical sectioning of living renal tissue to obtain histological images by multiphoton microscopy (MPM). Here, we demonstrated that the MPM imaging with food dyes, including erythrosine and indigo carmine, could be used as fluorescent agents to visualize renal functions and structures such as glomerular bloodstreams, glomerular filtration, and morphology of glomeruli and renal tubules. We also showed that the kidneys of IgA nephropathy model-mice stained with the food dyes presented histopathological characteristics different from those observed in normal kidneys. The use of the food dyes enhances the quality of tissue images obtained by MPM and offers the potential to contribute to a clinical real-time diagnosis of kidney diseases. PMID:26260138

  12. 5-HT spatial distribution imaging with multiphoton excitation of 5-HT correlative visible fluorescence in live cells

    NASA Astrophysics Data System (ADS)

    Zhang, Zhihong; Zeng, Shaoqun; Liu, Yafeng; Zhou, Wei; Chen, Tongsheng; Luo, Qingming

    2002-04-01

    The autofluorescence of 5-Hydroxytryptamine (5-HT) loaded rat mucosal mast cells (RBL-2H3 cells) is imaged with multiphoton excitation laser scanning microscope (MPELSM). 5-HT correlative visible fluorescence (Fco-vis) excited with 740-nm multiphoton excitation is observed in live cells for the first time, and the generating mechanism of 5-HT Fco-vis is studied. The spatial distribution of 5-HT in live cells is imaged at high spatial resolution in our experiment, which provides a new way to study the correlation between 5-HT spatial distribution and content, and the cellular functional state in live tissue or cells.

  13. Time-resolved multiphoton imaging of basal cell carcinoma

    NASA Astrophysics Data System (ADS)

    Cicchi, R.; Sestini, S.; De Giorgi, V.; Stambouli, D.; Carli, P.; Massi, D.; Pavone, F. S.

    2007-02-01

    We investigated human cutaneous basal cell carcinoma ex-vivo samples by combined time resolved two photon intrinsic fluorescence and second harmonic generation microscopy. Morphological and spectroscopic differences were found between malignant skin and corresponding healthy skin tissues. In comparison with normal healthy skin, cancer tissue showed a different morphology and a mean fluorescence lifetime distribution slightly shifted towards higher values. Topical application of delta-aminolevulinic acid to the lesion four hours before excision resulted in an enhancement of the fluorescence signal arising from malignant tissue, due to the accumulation of protoporphyrines inside tumor cells. Contrast enhancement was prevalent at tumor borders by both two photon fluorescence microscopy and fluorescence lifetime imaging. Fluorescence-based images showed a good correlation with conventional histopathological analysis, thereby supporting the diagnostic accuracy of this novel method. Combined morphological and lifetime analysis in the study of ex-vivo skin samples discriminated benign from malignant tissues, thus offering a reliable, non-invasive tool for the in-vivo analysis of inflammatory and neoplastic skin lesions.

  14. Multi-photon imaging of amine-functionalized silica nanoparticles

    NASA Astrophysics Data System (ADS)

    Natalio, Filipe; Kashyap, Anubha; Lorenz, Steffen; Kerschbaumer, Hannes; Dietzsch, Michael; Tahir, Muhammad Nawaz; Duschner, Heinz; Strand, Susanne; Strand, Dennis; Tremel, Wolfgang

    2012-07-01

    A convenient and simple strategy for preparing water soluble, photoluminescent functionalized silica nanoparticles (M-dots) in the absence of fluorophores or metal doping is demonstrated. These M-dots can be used for bioimaging using one and two-photon microscopy. Because of their high photostability, low toxicity and high biocompatibility compared with Lumidot™ CdSe/ZnS quantum dots, functionalized silica particles are superior alternatives for current bioimaging platforms. Moreover, the presence of a free amine group at the surface of the M-dots allows biomolecule conjugation (e.g. with antibodies, proteins) in a single step for converting these photoluminescent SiO2 nanoparticles into multifunctional efficient vehicles for theragnostics.A convenient and simple strategy for preparing water soluble, photoluminescent functionalized silica nanoparticles (M-dots) in the absence of fluorophores or metal doping is demonstrated. These M-dots can be used for bioimaging using one and two-photon microscopy. Because of their high photostability, low toxicity and high biocompatibility compared with Lumidot™ CdSe/ZnS quantum dots, functionalized silica particles are superior alternatives for current bioimaging platforms. Moreover, the presence of a free amine group at the surface of the M-dots allows biomolecule conjugation (e.g. with antibodies, proteins) in a single step for converting these photoluminescent SiO2 nanoparticles into multifunctional efficient vehicles for theragnostics. Electronic supplementary information (ESI) available: TEM images of unfunctionalized, XRD, UV-Vis spectra, XPS spectra and gallery of two-photon images. See DOI: 10.1039/c2nr30660c

  15. Deep-tissue multiphoton fluorescence lifetime microscopy for intravital imaging of protein-protein interactions

    NASA Astrophysics Data System (ADS)

    Fruhwirth, G. O.; Matthews, D. R.; Brock, A.; Keppler, M.; Vojnovic, B.; Ng, T.; Ameer-Beg, S.

    2009-02-01

    Fluorescent lifetime imaging microscopy (FLIM) has proven to be a valuable tool in beating the Rayleigh criterion for light microscopy by measuring Förster resonance energy transfer (FRET) between two fluorophores. Applying multiphoton FLIM, we previously showed in a human breast cancer cell line that recycling of a membrane receptorgreen fluorescent protein fusion is enhanced concomitantly with the formation of a receptor:protein kinase C α complex in the endosomal compartment. We have extended this established technique to probe direct protein-protein interactions also in vivo. Therefore, we used various expressible fluorescent tags fused to membrane receptor molecules in order to generate stable two-colour breast carcinoma cell lines via controlled retroviral infection. We used these cell lines for establishing a xenograft tumour model in immune-compromised Nude mice. Using this animal model in conjunction with scanning Ti:Sapphire laser-based two-photon excitation, we established deep-tissue multiphoton FLIM in vivo. For the first time, this novel technique enables us to directly assess donor fluorescence lifetime changes in vivo and we show the application of this method for intravital imaging of direct protein-protein interactions.

  16. Multiphoton microscopic imaging of fibrotic focus in invasive ductal carcinoma of the breast

    NASA Astrophysics Data System (ADS)

    Chen, Sijia; Nie, Yuting; Lian, Yuane; Wu, Yan; Fu, Fangmeng; Wang, Chuan; Zhuo, Shuangmu; Chen, Jianxin

    2014-11-01

    During the proliferation of breast cancer, the desmoplastic can evoke a fibrosis response by invading healthy tissue. Fibrotic focus (FF) in invasive ductal carcinoma (IDC) of the breast had been reported to be associated with significantly poorer survival rate than IDC without FF. As an important prognosis indicator, it's difficult to obtain the exact fibrotic information from traditional detection method such as mammography. Multiphoton imaging based on two-photon excited fluorescence (TPEF) and second-harmonic generation (SHG) has been recently employed for microscopic examination of unstained tissue. In this study, multiphoton microscopy (MPM) was used to image the fibrotic focus in invasive ductal carcinoma tissue. The morphology and distribution of collagen in fibrotic focus can be demonstrated by the SHG signal. Variation of collagen between IDC with and without FF will be examined and further characterized, which may be greatly related to the metastasis of breast cancer. Our result suggested that the MPM can be efficient in identifying and locating the fibrotic focus in IDC. Combining with the pathology analysis and other detecting methods, MPM owns potential in becoming an advanced histological tool for detecting the fibrotic focus in IDC and collecting prognosis information, which may guide the subsequent surgery option and therapy procedure for patients.

  17. Hybrid multiphoton volumetric functional imaging of large-scale bioengineered neuronal networks

    NASA Astrophysics Data System (ADS)

    Dana, Hod; Marom, Anat; Paluch, Shir; Dvorkin, Roman; Brosh, Inbar; Shoham, Shy

    2014-06-01

    Planar neural networks and interfaces serve as versatile in vitro models of central nervous system physiology, but adaptations of related methods to three dimensions (3D) have met with limited success. Here, we demonstrate for the first time volumetric functional imaging in a bioengineered neural tissue growing in a transparent hydrogel with cortical cellular and synaptic densities, by introducing complementary new developments in nonlinear microscopy and neural tissue engineering. Our system uses a novel hybrid multiphoton microscope design combining a 3D scanning-line temporal-focusing subsystem and a conventional laser-scanning multiphoton microscope to provide functional and structural volumetric imaging capabilities: dense microscopic 3D sampling at tens of volumes per second of structures with mm-scale dimensions containing a network of over 1,000 developing cells with complex spontaneous activity patterns. These developments open new opportunities for large-scale neuronal interfacing and for applications of 3D engineered networks ranging from basic neuroscience to the screening of neuroactive substances.

  18. Role of multiphoton bunching in high-order ghost imaging with thermal light sources

    SciTech Connect

    Liu Qian; Chen Xihao; Luo Kaihong; Wu Lingan; Wu Wei

    2009-05-15

    The intrinsic higher-order correlation of intensities which gives a measure of 'pure' correlations among photons (corresponding to multiphoton bunching) is investigated with regard to ghost imaging with thermal light. The synchronous detection of the same light field by all reference detectors, which is a necessary condition for achieving an Nth-order ghost image based on N-photon bunching, is discussed. Furthermore, it is found that the enhanced high visibility of Nth-order ghost imaging is a consequence of the contribution of N-photon bunching, which is not a small value but is equal to the sum of all contributions from (N-1)-photon bunching. These results differ from those obtained by certain other groups.

  19. MEMS-based multiphoton endomicroscope for repetitive imaging of mouse colon

    PubMed Central

    Duan, Xiyu; Li, Haijun; Qiu, Zhen; Joshi, Bishnu P.; Pant, Asha; Smith, Arlene; Kurabayashi, Katsuo; Oldham, Kenn R.; Wang, Thomas D.

    2015-01-01

    We demonstrate a handheld multiphoton endomicroscope with 3.4 mm distal diameter that can repetitively image mouse colon in vivo. A 2D resonant MEMS mirror was developed to perform beam scanning in a Lissajous pattern. The instrument has an effective numerical aperture of 0.63, lateral and axial resolution of 2.03 and 9.02 μm, respectively, working distance of 60 μm, and image field-of-view of 300 × 300 μm2. Hoechst was injected intravenously in mice to stain cell nuclei. We were able to collect histology-like images in vivo at 5 frames/sec, and distinguish between normal and pre-malignant colonic epithelium. PMID:26309768

  20. Label-free in vivo imaging of Drosophila melanogaster by multiphoton microscopy

    NASA Astrophysics Data System (ADS)

    Lin, Chiao-Ying; Hovhannisyan, Vladimir; Wu, June-Tai; Lin, Sung-Jan; Lin, Chii-Wann; Chen, Jyh-Horng; Dong, Chen-Yuan

    2008-02-01

    The fruit fly Drosophila melanogaster is one of the most valuable organisms in genetic and developmental biology studies. Drosophila is a small organism with a short life cycle, and is inexpensive and easy to maintain. The entire genome of Drosophila has recently been sequenced (cite the reference). These advantages make fruit fly an attractive model organism for biomedical researches. Unlike humans, Drosophila can be subjected to genetic manipulation with relative ease. Originally, Drosophila was mostly used in classical genetics studies. In the model era of molecular biology, the fruit fly has become a model organ for developmental biology researches. In the past, numerous molecularly modified mutants with well defined genetic defects affecting different aspects of the developmental processes have been identified and studied. However, traditionally, the developmental defects of the mutant flies are mostly examined in isolated fixed tissues which preclude the observation of the dynamic interaction of the different cell types and the extracellular matrix. Therefore, the ability to image different organelles of the fruit fly without extrinsic labeling is invaluable for Drosophila biology. In this work, we successfully acquire in vivo images of both developing muscles and axons of motor neurons in the three larval stages by using the minimially invasive imaging modality of multiphoton (SHG) microscopy. We found that while SHG imaging is useful in revealing the muscular architecture of the developing larva, it is the autofluorescence signal that allows label-free imaging of various organelles to be achieved. Our results demonstrate that multiphoton imaging is a powerful technique for investigation the development of Drosophila.

  1. Spectral imaging of the retina

    PubMed Central

    Mordant, D J; Al-Abboud, I; Muyo, G; Gorman, A; Sallam, A; Ritchie, P; Harvey, A R; McNaught, A I

    2011-01-01

    Introduction The work described here involved the use of a modified fundus camera to obtain sequential hyperspectral images of the retina in 14 normal volunteers and in 1 illustrative patient with a retinal vascular occlusion. Methods The paper describes analysis techniques, which allow oximetry within retinal vessels; these results are presented as retinal oximetry maps. Results Using spectral images, with wavelengths between 556 and 650 nm, the mean oxygen saturation (OS) value in temporal retinal arterioles in normal volunteers was 104.3 (±16.7), and in normal temporal retinal venules was 34.8 (±17.8). These values are comparable to those quoted in the literature, although, the venular saturations are slightly lower than those values found by other authors; explanations are offered for these differences. Discussion The described imaging and analysis techniques produce a clinically useful map of retinal oximetric values. The results from normal volunteers and from one illustrative patient are presented. Further developments, including the recent development of a ‘snapshot' spectral camera, promises enhanced non-invasive retinal vessel oximetry mapping. PMID:21390065

  2. Spectral clustering for TRUS images

    PubMed Central

    Mohamed, Samar S; Salama, Magdy MA

    2007-01-01

    Background Identifying the location and the volume of the prostate is important for ultrasound-guided prostate brachytherapy. Prostate volume is also important for prostate cancer diagnosis. Manual outlining of the prostate border is able to determine the prostate volume accurately, however, it is time consuming and tedious. Therefore, a number of investigations have been devoted to designing algorithms that are suitable for segmenting the prostate boundary in ultrasound images. The most popular method is the deformable model (snakes), a method that involves designing an energy function and then optimizing this function. The snakes algorithm usually requires either an initial contour or some points on the prostate boundary to be estimated close enough to the original boundary which is considered a drawback to this powerful method. Methods The proposed spectral clustering segmentation algorithm is built on a totally different foundation that doesn't involve any function design or optimization. It also doesn't need any contour or any points on the boundary to be estimated. The proposed algorithm depends mainly on graph theory techniques. Results Spectral clustering is used in this paper for both prostate gland segmentation from the background and internal gland segmentation. The obtained segmented images were compared to the expert radiologist segmented images. The proposed algorithm obtained excellent gland segmentation results with 93% average overlap areas. It is also able to internally segment the gland where the segmentation showed consistency with the cancerous regions identified by the expert radiologist. Conclusion The proposed spectral clustering segmentation algorithm obtained fast excellent estimates that can give rough prostate volume and location as well as internal gland segmentation without any user interaction. PMID:17359549

  3. Heuristically optimal path scanning for high-speed multiphoton circuit imaging.

    PubMed

    Sadovsky, Alexander J; Kruskal, Peter B; Kimmel, Joseph M; Ostmeyer, Jared; Neubauer, Florian B; MacLean, Jason N

    2011-09-01

    Population dynamics of patterned neuronal firing are fundamental to information processing in the brain. Multiphoton microscopy in combination with calcium indicator dyes allows circuit dynamics to be imaged with single-neuron resolution. However, the temporal resolution of fluorescent measures is constrained by the imaging frequency imposed by standard raster scanning techniques. As a result, traditional raster scans limit the ability to detect the relative timing of action potentials in the imaged neuronal population. To maximize the speed of fluorescence measures from large populations of neurons using a standard multiphoton laser scanning microscope (MPLSM) setup, we have developed heuristically optimal path scanning (HOPS). HOPS optimizes the laser travel path length, and thus the temporal resolution of neuronal fluorescent measures, using standard galvanometer scan mirrors. Minimizing the scan path alone is insufficient for prolonged high-speed imaging of neuronal populations. Path stability and the signal-to-noise ratio become increasingly important factors as scan rates increase. HOPS addresses this by characterizing the scan mirror galvanometers to achieve prolonged path stability. In addition, the neuronal dwell time is optimized to sharpen the detection of action potentials while maximizing scan rate. The combination of shortest path calculation and minimization of mirror positioning time allows us to optically monitor a population of neurons in a field of view at high rates with single-spike resolution, ∼ 125 Hz for 50 neurons and ∼ 8.5 Hz for 1,000 neurons. Our approach introduces an accessible method for rapid imaging of large neuronal populations using traditional MPLSMs, facilitating new insights into neuronal circuit dynamics. PMID:21715667

  4. In vivo multiphoton imaging of human skin: assessment of topical corticosteroid-induced epidermis atrophy and depigmentation

    NASA Astrophysics Data System (ADS)

    Ait El Madani, Hassan; Tancrède-Bohin, Emmanuelle; Bensussan, Armand; Colonna, Anne; Dupuy, Alain; Bagot, Martine; Pena, Ana-Maria

    2012-02-01

    Multiphoton microscopy has emerged in the past decade as a promising tool for noninvasive skin imaging. Our aim was to evaluate the potential of multiphoton microscopy to detect topical corticosteroids side effects within the epidermis and to provide new insights into their dynamics. Healthy volunteers were topically treated with clobetasol propionate on a small region of their forearms under overnight occlusion for three weeks. The treated region of each patient was investigated at D0, D7, D15, D22 (end of the treatment), and D60. Our study shows that multiphoton microscopy allows for the detection of corticoid-induced epidermis modifications: thinning of stratum corneum compactum and epidermis, decrease of keratinocytes size, and changes in their morphology from D7 to D22. We also show that multiphoton microscopy enables in vivo three-dimensional (3-D) quantitative assessment of melanin content. We observe that melanin density decreases during treatment and almost completely disappears at D22. Moreover, these alterations are reversible as they are no longer present at D60. Our study demonstrates that multiphoton microscopy is a convenient and powerful tool for noninvasive 3-D dynamical studies of skin integrity and pigmentation.

  5. From morphology to biochemical state - intravital multiphoton fluorescence lifetime imaging of inflamed human skin.

    PubMed

    Huck, Volker; Gorzelanny, Christian; Thomas, Kai; Getova, Valentina; Niemeyer, Verena; Zens, Katharina; Unnerstall, Tim R; Feger, Julia S; Fallah, Mohammad A; Metze, Dieter; Ständer, Sonja; Luger, Thomas A; Koenig, Karsten; Mess, Christian; Schneider, Stefan W

    2016-01-01

    The application of multiphoton microscopy in the field of biomedical research and advanced diagnostics promises unique insights into the pathophysiology of inflammatory skin diseases. In the present study, we combined multiphoton-based intravital tomography (MPT) and fluorescence lifetime imaging (MPT-FLIM) within the scope of a clinical trial of atopic dermatitis with the aim of providing personalised data on the aetiopathology of inflammation in a non-invasive manner at patients' bedsides. These 'optical biopsies' generated via MPT were morphologically analysed and aligned with classical skin histology. Because of its subcellular resolution, MPT provided evidence of a redistribution of mitochondria in keratinocytes, indicating an altered cellular metabolism. Two independent morphometric algorithms reliably showed an even distribution in healthy skin and a perinuclear accumulation in inflamed skin. Moreover, using MPT-FLIM, detection of the onset and progression of inflammatory processes could be achieved. In conclusion, the change in the distribution of mitochondria upon inflammation and the verification of an altered cellular metabolism facilitate a better understanding of inflammatory skin diseases and may permit early diagnosis and therapy. PMID:27004454

  6. Imaging normal and cancerous human gastric muscular layer in transverse and longitudinal sections by multiphoton microscopy.

    PubMed

    Zhou, Yi; Kang, Deyong; Yang, Zhenrong; Li, Lianhuang; Zhuo, Shuangmu; Zhu, Xiaoqin; Zhou, Yongjian; Chen, Jianxin

    2016-07-01

    Multiphoton microscopy (MPM) based on two-photon excited fluorescence (TPEF) and second harmonic generation (SHG) has been widely used for imaging microstructure of biological tissues. In this article, we used MPM to investigate the microstructure changes of normal and cancerous human gastric muscular layer in transverse and longitudinal sections. The results displayed different patterns of microstructure changes of smooth muscular tissue, cell morphology and interstitial fibers in transverse and longitudinal sections, being similar to standard histopathological images but without the need for tissue processing. Our study demonstrated that MPM can bring more detailed complementary information on tissue architecture through observing transverse and longitudinal sections of tissues, which are the important pathological information when the pathologists diagnose the gastrointestinal lesions. These observations indicate that MPM could be an important potential tool to provide real-time pathological diagnosis for gastric cancer in the future. SCANNING 38:357-364, 2016. © 2015 Wiley Periodicals, Inc. PMID:26435529

  7. Automatic centerline extraction of irregular tubular structures using probability volumes from multiphoton imaging.

    PubMed

    Santamaría-Pang, A; Colbert, C M; Saggau, P; Kakadiaris, I A

    2007-01-01

    In this paper, we present a general framework for extracting 3D centerlines from volumetric datasets. Unlike the majority of previous approaches, we do not require a prior segmentation of the volume nor we do assume any particular tubular shape. Centerline extraction is performed using a morphology-guided level set model. Our approach consists of: i) learning the structural patterns of a tubular-like object, and ii) estimating the centerline of a tubular object as the path with minimal cost with respect to outward flux in gray level images. Such shortest path is found by solving the Eikonal equation. We compare the performance of our method with existing approaches in synthetic, CT, and multiphoton 3D images, obtaining substantial improvements, especially in the case of irregular tubular objects. PMID:18044604

  8. Imaging photoelectron circular dichroism of chiral molecules by femtosecond multiphoton coincidence detection

    SciTech Connect

    Lehmann, C. Stefan; Ram, N. Bhargava; Janssen, Maurice H. M.; Powis, Ivan

    2013-12-21

    Here, we provide a detailed account of novel experiments employing electron-ion coincidence imaging to discriminate chiral molecules. The full three-dimensional angular scattering distribution of electrons is measured after photoexcitation with either left or right circular polarized light. The experiment is performed using a simplified photoelectron-photoion coincidence imaging setup employing only a single particle imaging detector. Results are reported applying this technique to enantiomers of the chiral molecule camphor after three-photon ionization by circularly polarized femtosecond laser pulses at 400 nm and 380 nm. The electron-ion coincidence imaging provides the photoelectron spectrum of mass-selected ions that are observed in the time-of-flight mass spectra. The coincident photoelectron spectra of the parent camphor ion and the various fragment ions are the same, so it can be concluded that fragmentation of camphor happens after ionization. We discuss the forward-backward asymmetry in the photoelectron angular distribution which is expressed in Legendre polynomials with moments up to order six. Furthermore, we present a method, similar to one-photon electron circular dichroism, to quantify the strength of the chiral electron asymmetry in a single parameter. The circular dichroism in the photoelectron angular distribution of camphor is measured to be 8% at 400 nm. The electron circular dichroism using femtosecond multiphoton excitation is of opposite sign and about 60% larger than the electron dichroism observed before in near-threshold one-photon ionization with synchrotron excitation. We interpret our multiphoton ionization as being resonant at the two-photon level with the 3s and 3p Rydberg states of camphor. Theoretical calculations are presented that model the photoelectron angular distribution from a prealigned camphor molecule using density functional theory and continuum multiple scattering X alpha photoelectron scattering calculations

  9. Imaging photoelectron circular dichroism of chiral molecules by femtosecond multiphoton coincidence detection

    NASA Astrophysics Data System (ADS)

    Lehmann, C. Stefan; Ram, N. Bhargava; Powis, Ivan; Janssen, Maurice H. M.

    2013-12-01

    Here, we provide a detailed account of novel experiments employing electron-ion coincidence imaging to discriminate chiral molecules. The full three-dimensional angular scattering distribution of electrons is measured after photoexcitation with either left or right circular polarized light. The experiment is performed using a simplified photoelectron-photoion coincidence imaging setup employing only a single particle imaging detector. Results are reported applying this technique to enantiomers of the chiral molecule camphor after three-photon ionization by circularly polarized femtosecond laser pulses at 400 nm and 380 nm. The electron-ion coincidence imaging provides the photoelectron spectrum of mass-selected ions that are observed in the time-of-flight mass spectra. The coincident photoelectron spectra of the parent camphor ion and the various fragment ions are the same, so it can be concluded that fragmentation of camphor happens after ionization. We discuss the forward-backward asymmetry in the photoelectron angular distribution which is expressed in Legendre polynomials with moments up to order six. Furthermore, we present a method, similar to one-photon electron circular dichroism, to quantify the strength of the chiral electron asymmetry in a single parameter. The circular dichroism in the photoelectron angular distribution of camphor is measured to be 8% at 400 nm. The electron circular dichroism using femtosecond multiphoton excitation is of opposite sign and about 60% larger than the electron dichroism observed before in near-threshold one-photon ionization with synchrotron excitation. We interpret our multiphoton ionization as being resonant at the two-photon level with the 3s and 3p Rydberg states of camphor. Theoretical calculations are presented that model the photoelectron angular distribution from a prealigned camphor molecule using density functional theory and continuum multiple scattering X alpha photoelectron scattering calculations

  10. Spectral image reconstruction through the PCA transform

    NASA Astrophysics Data System (ADS)

    Ma, Long; Qiu, Xuewei; Cong, Yangming

    2015-12-01

    Digital color image reproduction based on spectral information has become a field of much interest and practical importance in recent years. The representation of color in digital form with multi-band images is not very accurate, hence the use of spectral image is justified. Reconstructing high-dimensional spectral reflectance images from relatively low-dimensional camera signals is generally an ill-posed problem. The aim of this study is to use the Principal component analysis (PCA) transform in spectral reflectance images reconstruction. The performance is evaluated by the mean, median and standard deviation of color difference values. The values of mean, median and standard deviation of root mean square (GFC) errors between the reconstructed and the actual spectral image were also calculated. Simulation experiments conducted on a six-channel camera system and on spectral test images show the performance of the suggested method.

  11. New developments in multimodal clinical multiphoton tomography

    NASA Astrophysics Data System (ADS)

    König, Karsten

    2011-03-01

    80 years ago, the PhD student Maria Goeppert predicted in her thesis in Goettingen, Germany, two-photon effects. It took 30 years to prove her theory, and another three decades to realize the first two-photon microscope. With the beginning of this millennium, first clinical multiphoton tomographs started operation in research institutions, hospitals, and in the cosmetic industry. The multiphoton tomograph MPTflexTM with its miniaturized flexible scan head became the Prism-Award 2010 winner in the category Life Sciences. Multiphoton tomographs with its superior submicron spatial resolution can be upgraded to 5D imaging tools by adding spectral time-correlated single photon counting units. Furthermore, multimodal hybrid tomographs provide chemical fingerprinting and fast wide-field imaging. The world's first clinical CARS studies have been performed with a hybrid multimodal multiphoton tomograph in spring 2010. In particular, nonfluorescent lipids and water as well as mitochondrial fluorescent NAD(P)H, fluorescent elastin, keratin, and melanin as well as SHG-active collagen have been imaged in patients with dermatological disorders. Further multimodal approaches include the combination of multiphoton tomographs with low-resolution imaging tools such as ultrasound, optoacoustic, OCT, and dermoscopy systems. Multiphoton tomographs are currently employed in Australia, Japan, the US, and in several European countries for early diagnosis of skin cancer (malignant melanoma), optimization of treatment strategies (wound healing, dermatitis), and cosmetic research including long-term biosafety tests of ZnO sunscreen nanoparticles and the measurement of the stimulated biosynthesis of collagen by anti-ageing products.

  12. Staring 2-D hadamard transform spectral imager

    DOEpatents

    Gentry, Stephen M.; Wehlburg, Christine M.; Wehlburg, Joseph C.; Smith, Mark W.; Smith, Jody L.

    2006-02-07

    A staring imaging system inputs a 2D spatial image containing multi-frequency spectral information. This image is encoded in one dimension of the image with a cyclic Hadamarid S-matrix. The resulting image is detecting with a spatial 2D detector; and a computer applies a Hadamard transform to recover the encoded image.

  13. The first decade of using multiphoton microscopy for high-power kidney imaging

    PubMed Central

    Burford, James L.; Hackl, Matthias J.

    2012-01-01

    In this review, we highlight the major scientific breakthroughs in kidney research achieved using multiphoton microscopy (MPM) and summarize the milestones in the technological development of kidney MPM during the past 10 years. Since more and more renal laboratories invest in MPM worldwide, we discuss future directions and provide practical, useful tips and examples for the application of this still-emerging optical sectioning technology. Advantages of using MPM in various kidney preparations that range from freshly dissected individual glomeruli or the whole kidney in vitro to MPM of the intact mouse and rat kidney in vivo are reviewed. Potential combinations of MPM with micromanipulation techniques including microperfusion and micropuncture are also included. However, we emphasize the most advanced and complex, quantitative in vivo imaging applications as the ultimate use of MPM since the true mandate of this technology is to look inside intact organs in live animals and humans. PMID:22031850

  14. Marginal characteristics of skin scarred dermis quantitatively extracted from multiphoton microscopic imaging

    NASA Astrophysics Data System (ADS)

    Zhu, Xiaoqin; Zhuo, Shuangmu; Zheng, Liqin; Jiang, Xingshan; Chen, Jianxin; Lin, Bifang

    2010-11-01

    Multiphoton microscopy based on two-photon excited fluorescence (TPEF) and second harmonic generation (SHG) was applied to examine the marginal regions at dermis of normal, atrophic and keloid scars. High-contrast, high-resolution image showed an obvious boundary at scar margin and different morphological patterns of collagen or elastin on the two sides. Since the degree of the morphological alteration between the two sides of boundary at scar margin was varied among different types of scars, alteration degree of SHG-to-TPEF index was defined as a quantitative indicator for discrimination. It will help to determine the most appropriate clinical treatment strategy for different types of scars and potentially monitor therapy in vivo.

  15. Label-free multi-photon imaging of dysplasia in Barrett’s esophagus

    PubMed Central

    Mehravar, Soroush; Banerjee, Bhaskar; Chatrath, Hemant; Amirsolaimani, Babak; Patel, Krunal; Patel, Charmi; Norwood, Robert A; Peyghambarian, Nasser; Kieu, Khanh

    2015-01-01

    Barrett’s esophagus (BE) is a metaplastic disorder where dysplastic and early cancerous changes are invisible to the naked eye and where the practice of blind biopsy is hampered by large sampling errors. Multi-photon microscopy (MPM) has emerged as an alternative solution for fast and label-free diagnostic capability for identifying the histological features with sub-micron accuracy. We developed a compact, inexpensive MPM system by using a handheld mode-locked fiber laser operating at 1560nm to study mucosal biopsies of BE. The combination of back-scattered THG, back-reflected forward THG and SHG signals generate images of cell nuclei and collagen, leading to label-free diagnosis in Barrett’s. PMID:26819824

  16. A database for spectral image quality

    NASA Astrophysics Data System (ADS)

    Le Moan, Steven; George, Sony; Pedersen, Marius; Blahová, Jana; Hardeberg, Jon Yngve

    2015-01-01

    We introduce a new image database dedicated to multi-/hyperspectral image quality assessment. A total of nine scenes representing pseudo-at surfaces of different materials (textile, wood, skin. . . ) were captured by means of a 160 band hyperspectral system with a spectral range between 410 and 1000nm. Five spectral distortions were designed, applied to the spectral images and subsequently compared in a psychometric experiment, in order to provide a basis for applications such as the evaluation of spectral image difference measures. The database can be downloaded freely from http://www.colourlab.no/cid.

  17. Simultaneous multiple-excitation multiphoton microscopy yields increased imaging sensitivity and specificity

    PubMed Central

    2011-01-01

    Background Multiphoton microscopy (MPM) offers many advantages over conventional wide-field and confocal laser scanning microscopy (CLSM) for imaging biological samples such as 3D resolution of excitation, reduced phototoxicity, and deeper tissue imaging. However, adapting MPM for critical multi-color measurements presents a challenge because of the largely overlapping two-photon absorption (TPA) peaks of common biological fluorophores. Currently, most multi-color MPM relies on the absorbance at one intermediate wavelength of multiple dyes, which introduces problems such as decreased and unequal excitation efficiency across the set of dyes. Results Here we describe an MPM system incorporating two, independently controlled sources of two-photon excitation whose wavelengths are adjusted to maximally excite one dye while minimally exciting the other. We report increased signal-to-noise ratios and decreased false positive emission bleed-through using this novel multiple-excitation MPM (ME-MPM) compared to conventional single-excitation MPM (SE-MPM) in a variety of multi-color imaging applications. Conclusions Similar to the tremendous gain in popularity of CLSM after the introduction of multi-color imaging, we anticipate that the ME-MPM system will further increase the popularity of MPM. In addition, ME-MPM provides an excellent tool to more rapidly design and optimize pairs of fluorescence probes for multi-color two-photon imaging, such as CFP/YFP or GFP/DsRed for CLSM. PMID:21366923

  18. Multiphoton microscopy based cryo-imaging of inflated frozen human lung sections at -60°C in healthy and COPD lungs

    NASA Astrophysics Data System (ADS)

    Abraham, Thomas; Kayra, Damian; Zhang, Angela; Suzuki, Masaru; McDonough, John; Elliott, W. M.; Cooper, Joel D.; Hogg, James C.

    2013-02-01

    Lung is a complex gas exchanger with interfacial area (where the gas exchange takes place) is about the size of a tennis court. Respiratory function is linked to the biomechanical stability of the gas exchange or alveolar regions which directly depends on the spatial distributions of the extracellular matrix fibers such fibrillar collagens and elastin fibers. It is very important to visualize and quantify these fibers at their native and inflated conditions to have correct morphometric information on differences between control and diseased states. This can be only achieved in the ex vivo states by imaging directly frozen lung specimens inflated to total lung capacity. Multiphoton microscopy, which uses ultra-short infrared laser pulses as the excitation source, produces multiphoton excitation fluorescence (MPEF) signals from endogenously fluorescent proteins (e.g. elastin) and induces specific second harmonic generation (SHG) signals from non-centrosymmetric proteins such as fibrillar collagens in fresh human lung tissues [J. Struct. Biol. (2010)171,189-196]. Here we report for the first time 3D image data obtained directly from thick frozen inflated lung specimens (~0.7- 1.0 millimeter thick) visualized at -60°C without prior fixation or staining in healthy and diseased states. Lung specimens donated for transplantation and released for research when no appropriate recipient was identified served as controls, and diseased lung specimens donated for research by patients receiving lung transplantation for very severe COPD (n=4) were prepared as previously described [N. Engl. J. Med. (2011) 201, 1567]. Lung slices evenly spaced between apex and base were examined using multiphoton microscopy while maintained at -60°C using a temperature controlled cold stage with a temperature resolution of 0.1°C. Infrared femto-second laser pulses tuned to 880nm, dry microscopic objectives, and non-de-scanned detectors/spectrophotometer located in the reflection geometry were

  19. Multiphoton microscopy as a diagnostic imaging modality for pancreatic neoplasms without hematoxylin and eosin stains

    NASA Astrophysics Data System (ADS)

    Chen, Youting; Chen, Jing; Chen, Hong; Hong, Zhipeng; Zhu, Xiaoqin; Zhuo, Shuangmu; Chen, Yanling; Chen, Jianxin

    2014-09-01

    Hematoxylin and eosin (H&E) staining of tissue samples is the standard approach in histopathology for imaging and diagnosing cancer. Recent reports have shown that multiphoton microscopy (MPM) provides better sample interface with single-cell resolution, which enhances traditional H&E staining and offers a powerful diagnostic tool with potential applications in oncology. The purpose of this study was to further expand the versatility of MPM by establishing the optical parameters required for imaging unstained histological sections of pancreatic neoplasms, thereby providing an efficient and environmentally sustainable alternative to H&E staining while improving the accuracy of pancreatic cancer diagnoses. We found that the high-resolution MPM images clearly distinguish between the structure of normal pancreatic tissues compared with pancreatic neoplasms in unstained histological sections, and discernable differences in tissue architecture and cell morphology between normal versus tumorigenic cells led to enhanced optical diagnosis of cancerous tissue. Moreover, quantitative assessment of the cytomorphological features visualized from MPM images showed significant differences in the nuclear-cytoplasmic ratios of pancreatic neoplasms compared with normal pancreas, as well as further distinguished pancreatic malignant tumors from benign tumors. These results indicate that the MPM could potentially serve as an optical tool for the diagnosis of pancreatic neoplasms in unstained histological sections.

  20. Multiphoton microscopy as a diagnostic imaging modality for pancreatic neoplasms without hematoxylin and eosin stains.

    PubMed

    Chen, Youting; Chen, Jing; Chen, Hong; Hong, Zhipeng; Zhu, Xiaoqin; Zhuo, Shuangmu; Chen, Yanling; Chen, Jianxin

    2014-09-01

    Hematoxylin and eosin (H&E) staining of tissue samples is the standard approach in histopathology for imaging and diagnosing cancer. Recent reports have shown that multiphoton microscopy (MPM) provides better sample interface with single-cell resolution, which enhances traditional H&E staining and offers a powerful diagnostic tool with potential applications in oncology. The purpose of this study was to further expand the versatility of MPM by establishing the optical parameters required for imaging unstained histological sections of pancreatic neoplasms, thereby providing an efficient and environmentally sustainable alternative to H&E staining while improving the accuracy of pancreatic cancer diagnoses. We found that the high-resolution MPM images clearly distinguish between the structure of normal pancreatic tissues compared with pancreatic neoplasms in unstained histological sections, and discernable differences in tissue architecture and cell morphology between normal versus tumorigenic cells led to enhanced optical diagnosis of cancerous tissue. Moreover, quantitative assessment of the cytomorphological features visualized from MPM images showed significant differences in the nuclear–cytoplasmic ratios of pancreatic neoplasms compared with normal pancreas, as well as further distinguished pancreatic malignant tumors from benign tumors. These results indicate that the MPM could potentially serve as an optical tool for the diagnosis of pancreatic neoplasms in unstained histological sections. PMID:25216027

  1. Application of multiphoton steady state and lifetime imaging to mapping of tumor vascular architecture in vivo

    NASA Astrophysics Data System (ADS)

    Ameer-Beg, Simon; Barber, Paul R.; Hodgkiss, R. J.; Locke, R. J.; Newman, Robert G.; Tozer, Gillian M.; Vojnovic, Borivoj; Wilson, J.

    2002-06-01

    Recent interest in vascular targeting and anti-angiogenic drug treatments for cancer has stimulated fundamental research regarding the modes of action of these drugs as well as studies of the development and re-modeling of the vascular network following treatment. Multiphoton fluorescence microscopy is employed for in vivo mapping of three-dimensional blood vessel distribution in tumors grown in rodent dorsal skin-flap window chamber preparations. Accurate visualization of the vasculature in three-dimensions allows us to perform dynamic experiments in thick biological specimens in vivo. Examples of in vivo imaging of tumor vasculature are given and compared to normal tissue vasculature. The dynamic responses of blood vessels to treatment with the vascular targeting drug combretastatin A4-P are presented and discussed. The implementation of time-domain imaging by reversed stop-start time-correlated single photon counting (RSS-TCSPC) is discussed as a method for feature extraction in the presence of exogenous and endogenous fluorophores. In particular, the segmentation of the vascular network is demonstrated. Additional contrast, indicative of probe environmental factors, may also be realized. We present examples of in vivo lifetime imaging as a method to elucidate the physiological processes of the tumor microenvironment.

  2. Signal enhancement in multiphoton imaging by the use of coated glass substrates

    PubMed Central

    Lee, Sheng-Lin; Guo, Han-Wen; Chen, Yang-Fan; Dong, Chen-Yuan

    2015-01-01

    In nonlinear optical imaging of biological specimens, more than half of the generated luminescence signal is lost, when signal collection is performed in the epi-illuminated geometry. In this study, we enhanced the collected luminescence signal by the use of alternating multiply-coated layers of tantalum pentoxide (Ta2O5) and silicon dioxide (SiO2) on standard microscope cover glasses that has high transmission in the near-infrared wavelength region and high reflection of the visible, luminescence signal. Our coating is biocompatible, allows visual examination of the specimens and optimize collection of the luminescence signal. We demonstrated this approach on a number of specimens including sulforhodamine solution, fluorescence microspheres, and labeled 3T3 cells. In all cases, the use of coated cover glass enhanced signal, optimally by a factor of about 2. Image analysis of labeled 3T3 cells also shows signal enhancement did not contribute to additional photobleaching. Our results show that properly designed coated cover glass can enhance detected signal in multiphoton microscopy and result in improved image quality. PMID:26417521

  3. Signal enhancement in multiphoton imaging by the use of coated glass substrates.

    PubMed

    Lee, Sheng-Lin; Guo, Han-Wen; Chen, Yang-Fan; Dong, Chen-Yuan

    2015-09-01

    In nonlinear optical imaging of biological specimens, more than half of the generated luminescence signal is lost, when signal collection is performed in the epi-illuminated geometry. In this study, we enhanced the collected luminescence signal by the use of alternating multiply-coated layers of tantalum pentoxide (Ta2O5) and silicon dioxide (SiO2) on standard microscope cover glasses that has high transmission in the near-infrared wavelength region and high reflection of the visible, luminescence signal. Our coating is biocompatible, allows visual examination of the specimens and optimize collection of the luminescence signal. We demonstrated this approach on a number of specimens including sulforhodamine solution, fluorescence microspheres, and labeled 3T3 cells. In all cases, the use of coated cover glass enhanced signal, optimally by a factor of about 2. Image analysis of labeled 3T3 cells also shows signal enhancement did not contribute to additional photobleaching. Our results show that properly designed coated cover glass can enhance detected signal in multiphoton microscopy and result in improved image quality. PMID:26417521

  4. Use of multiphoton tomography and fluorescence lifetime imaging to investigate skin pigmentation in vivo

    NASA Astrophysics Data System (ADS)

    Dancik, Yuri; Favre, Amandine; Loy, Chong Jin; Zvyagin, Andrei V.; Roberts, Michael S.

    2013-02-01

    There is a growing body of literature showing the usefulness of multiphoton tomography (MPT) and fluorescence lifetime imaging for in situ characterization of skin constituents and the ensuing development of noninvasive diagnostic tools against skin diseases. Melanin and pigmentation-associated skin cancers constitute some of the major applications. We show that MPT and fluorescence lifetime imaging can be used to measure changes in cutaneous melanin concentration and that these can be related to the visible skin color. Melanin in the skin of African, Indian, Caucasian, and Asian volunteers is detected on the basis of its emission wavelength and fluorescence lifetimes in solution and in a melanocyte-keratinocyte cell culture. Fluorescence intensity is used to characterize the melanin content and distribution as a function of skin type and depth into the skin (stratum granulosum and stratum basale). The measured fluorescence intensities in given skin types agree with melanin amounts reported by others using biopsies. Our results suggest that spatial distribution of melanin in skin can be studied using MPT and fluorescence lifetime imaging, but further studies are needed to ascertain that the method can resolve melanin amount in smaller depth intervals.

  5. Combined multiphoton imaging and automated functional enucleation of porcine oocytes using femtosecond laser pulses

    NASA Astrophysics Data System (ADS)

    Kuetemeyer, Kai; Lucas-Hahn, Andrea; Petersen, Bjoern; Lemme, Erika; Hassel, Petra; Niemann, Heiner; Heisterkamp, Alexander

    2010-07-01

    Since the birth of ``Dolly'' as the first mammal cloned from a differentiated cell, somatic cell cloning has been successful in several mammalian species, albeit at low success rates. The highly invasive mechanical enucleation step of a cloning protocol requires sophisticated, expensive equipment and considerable micromanipulation skill. We present a novel noninvasive method for combined oocyte imaging and automated functional enucleation using femtosecond (fs) laser pulses. After three-dimensional imaging of Hoechst-labeled porcine oocytes by multiphoton microscopy, our self-developed software automatically identified the metaphase plate. Subsequent irradiation of the metaphase chromosomes with the very same laser at higher pulse energies in the low-density-plasma regime was used for metaphase plate ablation (functional enucleation). We show that fs laser-based functional enucleation of porcine oocytes completely inhibited the parthenogenetic development without affecting the oocyte morphology. In contrast, nonirradiated oocytes were able to develop parthenogenetically to the blastocyst stage without significant differences to controls. Our results indicate that fs laser systems have great potential for oocyte imaging and functional enucleation and may improve the efficiency of somatic cell cloning.

  6. Multiphoton Microscopy Applied for Real-Time Intravital Imaging of Bacterial Infections In Vivo

    PubMed Central

    Choong, Ferdinand X.; Sandoval, Ruben M.; Molitoris, Bruce A.; Richter-Dahlfors, Agneta

    2014-01-01

    To understand the underlying mechanisms of bacterial infections, researchers have for long addressed the molecular interactions occurring when the bacterium interacts with host target cells. In these studies, primarily based on in vitro systems, molecular details have been revealed along with increased knowledge regarding the general infection process. With the recent advancements in in vivo imaging techniques, we are now in a position to bridge a transition from classical minimalistic in vitro approaches to allow infections to be studied in its native complexity—the live organ. Techniques such as multiphoton microscopy (MPM) allow cellular-level visualization of the dynamic infection process in real time within the living host. Studies in which all interplaying factors, such as the influences of the immune, lymphatic, and vascular systems can be accounted for, are likely to provide new insights to our current understanding of the infection process. MPM imaging becomes extra powerful when combined with advanced surgical procedure, allowing studies of the illusive early hours of infection. In this chapter, our intention is to provide a general view on how to design and carry out intravital imaging of a bacterial infection. While exemplifying this using a spatiotemporally well-controlled uropathogenic Escherichia coli (UPEC) infection in rat kidneys, we hope to provide the reader with general considerations that can be adapted to other bacterial infections in organs other than the kidney. PMID:22341218

  7. Video-rate resonant scanning multiphoton microscopy: An emerging technique for intravital imaging of the tumor microenvironment.

    PubMed

    Kirkpatrick, Nathaniel D; Chung, Euiheon; Cook, Daniel C; Han, Xiaoxing; Gruionu, Gabriel; Liao, Shan; Munn, Lance L; Padera, Timothy P; Fukumura, Dai; Jain, Rakesh K

    2012-01-01

    The abnormal tumor microenvironment fuels tumor progression, metastasis, immune suppression, and treatment resistance. Over last several decades, developments in and applications of intravital microscopy have provided unprecedented insights into the dynamics of the tumor microenvironment. In particular, intravital multiphoton microscopy has revealed the abnormal structure and function of tumor-associated blood and lymphatic vessels, the role of aberrant tumor matrix in drug delivery, invasion and metastasis of tumor cells, the dynamics of immune cell trafficking to and within tumors, and gene expression in tumors. However, traditional multiphoton microscopy suffers from inherently slow imaging rates-only a few frames per second, thus unable to capture more rapid events such as blood flow, lymphatic flow, and cell movement within vessels. Here, we report the development and implementation of a video-rate multiphoton microscope (VR-MPLSM) based on resonant galvanometer mirror scanning that is capable of recording at 30 frames per second and acquiring intravital multispectral images. We show that the design of the system can be readily implemented and is adaptable to various experimental models. As examples, we demonstrate the utility of the system to directly measure flow within tumors, capture metastatic cancer cells moving within the brain vasculature and cells in lymphatic vessels, and image acute responses to changes in a vascular network. VR-MPLSM thus has the potential to further advance intravital imaging and provide new insight into the biology of the tumor microenvironment. PMID:24353926

  8. Design of a portable wide field of view GPU-accelerated multiphoton imaging system for real-time imaging of breast surgical specimens

    NASA Astrophysics Data System (ADS)

    Giacomelli, Michael G.; Yoshitake, Tadayuki; Husvogt, Lennart; Cahill, Lucas; Ahsen, Osman; Vardeh, Hilde; Sheykin, Yury; Faulkner-Jones, Beverly E.; Hornegger, Joachim; Brooker, Jeff; Cable, Alex; Connolly, James L.; Fujimoto, James G.

    2016-03-01

    We present a portable multiphoton system designed for evaluating centimeter-scale surgical margins on surgical breast specimens in a clinical setting. The system is designed to produce large field of view images at a high frame rate, while using GPU processing to render low latency, video-rate virtual H&E images for real-time assessment. The imaging system and virtual H&E rendering algorithm are demonstrated by imaging unfixed human breast tissue in a clinical setting.

  9. Imaging the morphological change of tissue structure during the early phase of esophageal tumor progression using multiphoton microscopy

    NASA Astrophysics Data System (ADS)

    Xu, Jian; Kang, Deyong; Xu, Meifang; Zhu, Xiaoqin; Zhuo, Shuangmu; Chen, Jianxin

    2012-12-01

    Esophageal cancer is a common malignancy with a very poor prognosis. Successful strategies for primary prevention and early detection are critically needed to control this disease. Multiphoton microscopy (MPM) is becoming a novel optical tool of choice for imaging tissue architecture and cellular morphology by two-photon excited fluorescence. In this study, we used MPM to image microstructure of human normal esophagus, carcinoma in situ (CIS), and early invasive carcinoma in order to establish the morphological features to differentiate these tissues. The diagnostic features such as the appearance of cancerous cells, the significant loss of stroma, the absence of the basement membrane were extracted to distinguish between normal and cancerous esophagus tissue. These results correlated well with the paired histological findings. With the advancement of clinically miniaturized MPM and the multi-photon probe, combining MPM with standard endoscopy will therefore allow us to make a real-time in vivo diagnosis of early esophageal cancer at the cellular level.

  10. Optimal spectral windows for microwave diversity imaging

    NASA Technical Reports Server (NTRS)

    Farhat, Nabil H.; Bai, Baocheng

    1991-01-01

    Tomographic microwave diversity imaging is analyzed using linear system theory concepts, and optimal spectral windows for data acquisition are obtained either by considering window position in the spectral domain or by using simulated annealing to find an optimal phase weighting of the object frequency response samples collected over the specified spectral window. This study provides a means of microwave image formation that is applicable under general assumptions. Results of numerical simulations and representative images reconstructed from realistic experimental microwave scattering data are given, demonstrating that the proposed approach is superior to previous image reconstruction methods.

  11. Spectral image compression for data communications

    NASA Astrophysics Data System (ADS)

    Hauta-Kasari, Markku; Lehtonen, Juha; Parkkinen, Jussi P. S.; Jaeaeskelaeinen, Timo

    2000-12-01

    We report a technique for spectral image compression to be used in the field of data communications. The spectral domain of the images is represented by a low-dimensional component image set, which is used to obtain an efficient compression of the high-dimensional spectral data. The component images are compressed using a similar technique as the JPEG- and MPEG-type compressions use to subsample the chrominance channels. The spectral compression is based on Principal Component Analysis (PCA) combined with color image transmission coding technique of 'chromatic channel subsampling' of the component images. The component images are subsampled using 4:2:2, 4:2:0, and 4:1:1-based compressions. In addition, we extended the test for larger block sizes and larger number of component images than in the original JPEG- and MPEG-standards. Totally 50 natural spectral images were used as test material in our experiments. Several error measures of the compression are reported. The same compressions are done using Independent Component Analysis and the results are compared with PCA. These methods give a good compression ratio while keeping visual quality of color still good. Quantitative comparisons between the original and reconstructed spectral images are presented.

  12. Multiphoton microscopy for imaging infectious keratitis: demonstration of the pattern of microbial spread in an experimental model

    NASA Astrophysics Data System (ADS)

    Sun, Yen; Lo, Wen; Wu, Ruei-Jhih; Lin, Sung-Jan; Lin, Wei-Chou; Jee, Shiou-Hwa; Tan, Hsin-Yuan; Dong, Chen-Yuan

    2006-02-01

    The purpose of this study is to assess the application of multiphoton fluorescence and second harmonic generation (SHG) microscopy for imaging and monitoring the disease progress of infectious keratitis in an experimental model, and to investigate the possible correlation of tissue architecture with spreading patterns of pathogens in an experimental model. Porcine eyes are to be obtained from slaughter house and processed and placed in organ culture system. Fungal infections by common pathogens of infectious keratitis are to be induced in porcine cornea buttons. Multiphoton fluorescence and SHG microscopy will be used for imaging and for monitoring the progression and extension of tissue destruction and possibly the pattern of pathogen spreading. We found that SHG imaging is useful in identifying alterations to collagen architecture while autofluorescence microscopy can be used to visualize the fungi and cells within the stroma. In summary, multiphoton fluorescence and second harmonic generation microscopy can non-invasively demonstrate and monitor tissue destruction associated with infectious keratitis. The pattern of pathogen spreading and its correlation with the tissue architecture can also be shown, which can be useful for future studies of the tissue-microbial interactions for infectious keratitis.

  13. Investigation of signal-to-noise ratio in frequency-domain multiphoton fluorescence lifetime imaging microscopy.

    PubMed

    Zhang, Yide; Khan, Aamir A; Vigil, Genevieve D; Howard, Scott S

    2016-07-01

    Multiphoton microscopy (MPM) combined with fluorescence lifetime imaging microscopy (FLIM) has enabled three-dimensional quantitative molecular microscopy in vivo. The signal-to-noise ratio (SNR), and thus the imaging rate of MPM-FLIM, which is fundamentally limited by the shot noise and fluorescence saturation, has not been quantitatively studied yet. In this paper, we investigate the SNR performance of the frequency-domain (FD) MPM-FLIM with two figures of merit: the photon economy in the limit of shot noise, and the normalized SNR in the limit of saturation. The theoretical results and Monte Carlo simulations find that two-photon FD-FLIM requires 50% fewer photons to achieve the same SNR as conventional one-photon FLIM. We also analytically show that the MPM-FD-FLIM can exploit the DC and higher harmonic components generated by nonlinear optical mixing of the excitation light to improve SNR, reducing the required number of photons by an additional 50%. Finally, the effect of fluorophore saturation on the experimental SNR performance is discussed. PMID:27409702

  14. Structural and functional imaging of engineered tissue development using an integrated OCT and multiphoton microscope

    NASA Astrophysics Data System (ADS)

    Fahrner, Lester J., IV; Tan, Wei; Vinegoni, Claudio; Eurell, Thomas E.; Boppart, Stephen A.

    2004-07-01

    Recent advances in the field of tissue engineering have led to the development of complex three-dimensional tissue constructs. It has become clear, however, that the traditional tools used for studying standard cell cultures are not always adequate for diagnostically studying thick, highly-scattering cultured tissues. Furthermore, many techniques used for studying three-dimensional constructs are invasive or require exogenous fluorophores, which damage the tissue and prevent time-course studies of tissue development. An integrated optical coherence tomography (OCT) and multi-photon microscope (MPM) has been constructed for visualizing 3-D engineered tissues. OCT was used for imaging structure and cell organization, while MPM was used for assessing functional properties of cells. We demonstrate technical developments involved in the construction of this instrument and its use in the non-destructive investigation of cell movement and tissue organization in engineered tissues. Cells labeled with GFP and exogenous fluorescent probes have also been imaged with OCT and confocal microscopy. Studies indicate that an integrated microscope has the potential to be an enabling diagnostic tool for future studies in the growth and organization of engineering tissues and in cell-cell and cell-matrix interactions.

  15. Imaging Mitochondrial Organization in Living Primate Oocytes and Embryos using Multiphoton Microscopy

    NASA Astrophysics Data System (ADS)

    Squirrell, J. M.; Schramm, R. D.; Paprocki, A. M.; Wokosin, D. L.; Bavister, B. D.

    2003-06-01

    We employed multiphoton laser scanning microscopy (MPLSM) to image changes in mitochondrial distribution in living rhesus monkey embryos. This method of imaging does not impair development; thus, the same specimen can be visualized multiple times at various developmental stages. Not only does this increase the amount of information that can be gathered on a single specimen but it permits the correlation of early events with subsequent development in the same specimen. Here we demonstrate the utility of MPLSM for determining changes in mitochondrial organization at various developmental stages and show that rhesus zygotes possess a distinct accumulation of mitochondria between the pronuclei prior to syngamy. We present evidence that suggests that this pronuclear accumulation may be positively correlated with development to the blastocyst stage—in the same embryo—thereby illustrating how MPLSM can be used to correlate cellular dynamics of primate oocytes and early embryos with their developmental potential. Understanding the relationship between mitochondrial distribution and the subsequent development of mammalian embryos, particularly primates, will increase our ability to improve embryo culture technologies, including those used for human assisted reproduction.

  16. Spectral modulation interferometry for quantitative phase imaging

    PubMed Central

    Shang, Ruibo; Chen, Shichao; Li, Chengshuai; Zhu, Yizheng

    2015-01-01

    We propose a spectral-domain interferometric technique, termed spectral modulation interferometry (SMI), and present its application to high-sensitivity, high-speed, and speckle-free quantitative phase imaging. In SMI, one-dimensional complex field of an object is interferometrically modulated onto a broadband spectrum. Full-field phase and intensity images are obtained by scanning along the orthogonal direction. SMI integrates the high sensitivity of spectral-domain interferometry with the high speed of spectral modulation to quantify fast phase dynamics, and its dispersive and confocal nature eliminates laser speckles. The principle and implementation of SMI are discussed. Its performance is evaluated using static and dynamic objects. PMID:25780737

  17. Corneal imaging and refractive index measurement using a combined multiphoton microscopy and optical coherence tomography system

    NASA Astrophysics Data System (ADS)

    Lai, Tom; Chong, Shau Poh; Zhou, Yifeng; Moloney, Gregory; Tang, Shuo

    2013-02-01

    Refractive index (RI) is the optical property of a medium that describes its ability to bend incident light. The corneal refractive index is an especially important measurement in corneal and intraocular refractive surgery where its precise estimation is necessary to obtain accurate surgical outcomes. In this study, we calculated the corneal RI using a combined multiphoton microscopy (MPM) and optical coherence tomography (OCT) system. MPM excites and detects nonlinear signals including two photon excitation fluorescence (TPEF) and second harmonic generation (SHG). TPEF signals are observed from NADH in the cytoplasm, allowing MPM to image the cellular structures in the corneal epithelium and endothelium. SHG signals are observed from collagen, an abundant connective tissue found in the stroma. Optical coherence tomography (OCT) produces cross-sectional, structural images based on the interference fringes created by the reflected light from the sample and reference arms. Our system uses a single sub-10 fs Ti: sapphire laser source which is good for both MPM excitation and OCT resolution. The MPM and OCT images are coregistered when they are taken successively because their axial resolutions are similar and the system shares the laser source and the scanning unit. We can calculate the RI by measuring the optical thickness and the optical path length of the cornea from the MPM and OCT images respectively. We have imaged and calculated the RI of murine and piscine corneas. We were able to see the epithelial, stromal, and endothelial layers and compare their relative thicknesses and the organization of the stromal collagen lamellae. Our results showed that our system can provide both functional and structural information about the cornea and measure the RI of multi-layered tissues.

  18. Nonlinear spectral imaging of biological tissues

    NASA Astrophysics Data System (ADS)

    Palero, J. A.

    2007-07-01

    The work presented in this thesis demonstrates live high resolution 3D imaging of tissue in its native state and environment. The nonlinear interaction between focussed femtosecond light pulses and the biological tissue results in the emission of natural autofluorescence and second-harmonic signal. Because biological intrinsic emission is generally very weak and extends from the ultraviolet to the visible spectral range, a broad-spectral range and high sensitivity 3D spectral imaging system is developed. Imaging the spectral characteristics of the biological intrinsic emission reveals the structure and biochemistry of the cells and extra-cellular components. By using different methods in visualizing the spectral images, discrimination between different tissue structures is achieved without the use of any stain or fluorescent label. For instance, RGB real color spectral images of the intrinsic emission of mouse skin tissues show blue cells, green hair follicles, and purple collagen fibers. The color signature of each tissue component is directly related to its characteristic emission spectrum. The results of this study show that skin tissue nonlinear intrinsic emission is mainly due to the autofluorescence of reduced nicotinamide adenine dinucleotide (phosphate), flavins, keratin, melanin, phospholipids, elastin and collagen and nonlinear Raman scattering and second-harmonic generation in Type I collagen. In vivo time-lapse spectral imaging is implemented to study metabolic changes in epidermal cells in tissues. Optical scattering in tissues, a key factor in determining the maximum achievable imaging depth, is also investigated in this work.

  19. Advanced multiphoton methods for in vitro and in vivo functional imaging of mouse retinal neurons (Conference Presentation)

    NASA Astrophysics Data System (ADS)

    Cohen, Noam; Schejter, Adi; Farah, Nairouz; Shoham, Shy

    2016-03-01

    Studying the responses of retinal ganglion cell (RGC) populations has major significance in vision research. Multiphoton imaging of optogenetic probes has recently become the leading approach for visualizing neural populations and has specific advantages for imaging retinal activity during visual stimulation, because it leads to reduced direct photoreceptor excitation. However, multiphoton retinal activity imaging is not straightforward: point-by-point scanning leads to repeated neural excitation while optical access through the rodent eye in vivo has proven highly challenging. Here, we present two enabling optical designs for multiphoton imaging of responses to visual stimuli in mouse retinas expressing calcium indicators. First, we present an imaging solution based on Scanning Line Temporal Focusing (SLITE) for rapidly imaging neuronal activity in vitro. In this design, we scan a temporally focused line rather than a point, increasing the scan speed and reducing the impact of repeated excitation, while maintaining high optical sectioning. Second, we present the first in vivo demonstration of two-photon imaging of RGC activity in the mouse retina. To obtain these cellular resolution recordings we integrated an illumination path into a correction-free imaging system designed using an optical model of the mouse eye. This system can image at multiple depths using an electronically tunable lens integrated into its optical path. The new optical designs presented here overcome a number of outstanding obstacles, allowing the study of rapid calcium- and potentially even voltage-indicator signals both in vitro and in vivo, thereby bringing us a step closer toward distributed monitoring of action potentials.

  20. Spectral OCT techniques in eye imaging

    NASA Astrophysics Data System (ADS)

    Kowalczyk, Andrzej; Wojtkowski, Maciej

    2002-02-01

    This contribution presents examples of images of eye in vitro obtained by spectral optical tomography (OCT). Particular interest was focused on obtaining clear images of the corneo-scleral angle and images of fundus which are both essential for diagnosing and planning of a treatment of glaucoma.

  1. Multiphoton imaging to identify grana, stroma thylakoid, and starch inside an intact leaf

    PubMed Central

    2014-01-01

    Background Grana and starch are major functional structures for photosynthesis and energy storage of plant, respectively. Both exhibit highly ordered molecular structures and appear as micrometer-sized granules inside chloroplasts. In order to distinguish grana and starch, we used multiphoton microscopy, with simultaneous acquisition of two-photon fluorescence (2PF) and second harmonic generation (SHG) signals. SHG is sensitive to crystallized structures while 2PF selectively reveals the distribution of chlorophyll. Result Three distinct microstructures with different contrasts were observed, i.e. “SHG dominates”, “2PF dominates”, and “SHG collocated with 2PF”. It is known that starch and grana both emit SHG due to their highly crystallized structures, and no autofluorescence is emitted from starch, so the “SHG dominates” contrast should correspond to starch. The contrast of “SHG collocated with 2PF” is assigned to be grana, which exhibit crystallized structure with autofluorescent chlorophyll. The “2PF dominates” contrast should correspond to stroma thylakoid, which is a non-packed membrane structure with chrolophyll. The contrast assignment is further supported by fluorescence lifetime measurement. Conclusion We have demonstrated a straightforward and noninvasive method to identify the distribution of grana and starch within an intact leaf. By merging the 2PF and SHG images, grana, starch and stroma thylakoid can be visually distinguished. This approach can be extended to the observation of 3D grana distribution and their dynamics in living plants. PMID:24969621

  2. Controlled Au-Polymer Nanostructures for Multiphoton Imaging, Prodrug Delivery, and Chemo-Photothermal Therapy Platforms.

    PubMed

    Huang, Chih-Chia; Liu, Tzu-Ming

    2015-11-18

    We have successfully introduced a proton-induced controlled reaction of HAuCl4 and poly(styrene-alt-maleic acid) (PSMA) sodium salt to prepare triangular and multicore Au@polymer nanoparticles (NPs). The interparticle interactions in the core gave rise to an absorption band at the near-infrared wavelength. The near-infrared optical properties of the resulting Au-polymer nanostructures are highly stable in a physiological environment, which offered strong photo-to-thermal conversion by a moderate continuous-wave 808 nm laser and exhibited multiphoton fluorescence for imaging using a 1230 nm light excitation (femtosecond laser). Exposure of the carboxylate groups at the polymer shell made the surface structure of the Au multicore @polymer NPs directly conjugate Pt(II)-/Pt(IV)-based drugs, which possessed the elimination of the immediate toxicity over the short time and resulted in an anticancer effect after 3 days. A synergistic effect of the chemo-photothermal therapy showed a moderate hyperthermia assistance (<1 W/cm(2)) and better anticancer performance over time compared with the individual treatments. We demonstrated that such PSMA-based methodology not only enables a broad range of chemical material synthesis in the kinetic control to form Au nano-octahedrons and nanotriangles using Br(-)/I(-) ions additives but also could be extended to form Au/Fe3O4@polymer nanocomposites via proton-assisted PSMA self-assembly. PMID:26501876

  3. Multi-spectral compressive snapshot imaging using RGB image sensors.

    PubMed

    Rueda, Hoover; Lau, Daniel; Arce, Gonzalo R

    2015-05-01

    Compressive sensing is a powerful sensing and reconstruction framework for recovering high dimensional signals with only a handful of observations and for spectral imaging, compressive sensing offers a novel method of multispectral imaging. Specifically, the coded aperture snapshot spectral imager (CASSI) system has been demonstrated to produce multi-spectral data cubes color images from a single snapshot taken by a monochrome image sensor. In this paper, we expand the theoretical framework of CASSI to include the spectral sensitivity of the image sensor pixels to account for color and then investigate the impact on image quality using either a traditional color image sensor that spatially multiplexes red, green, and blue light filters or a novel Foveon image sensor which stacks red, green, and blue pixels on top of one another. PMID:25969307

  4. Novel techniques with multiphoton microscopy: Deep-brain imaging with microprisms, neurometabolism of epilepsy, and counterfeit paper money detection

    NASA Astrophysics Data System (ADS)

    Chia, Thomas H.

    Multiphoton microscopy is a laser-scanning fluorescence imaging method with extraordinary potential. We describe three innovative multiphoton microscopy techniques across various disciplines. Traditional in vivo fluorescence microscopy of the mammalian brain has a limited penetration depth (<400 microm). We present a method of imaging 1 mm deep into mouse neocortex by using a glass microprism to relay the excitation and emission light. This technique enables simultaneous imaging of multiple cortical layers, including layer V, at an angle typical of slice preparations. At high-magnification imaging using an objective with 1-mm of coverglass correction, resolution was sufficient to resolve dendritic spines on layer V GFP neurons. Functional imaging of blood flow at various neocortical depths is also presented, allowing for quantification of red blood cell flux and velocity. Multiphoton fluorescence lifetime imaging (FLIM) of NADH reveals information on neurometabolism. NADH, an intrinsic fluorescent molecule and ubiquitous metabolic coenzyme, has a lifetime dependent on enzymatic binding. A novel NADH FLIM algorithm is presented that produces images showing spatially distinct NADH fluorescence lifetimes in mammalian brain slices. This program provides advantages over traditional FLIM processing of multi-component lifetime data. We applied this technique to a GFP-GFAP pilocarpine mouse model of temporal lobe epilepsy. Results indicated significant changes in the neurometabolism of astrocytes and neuropil in the cell and dendritic layers of the hippocampus when compared to control tissue. Data obtained with NADH FLIM were subsequently interpreted based on the abnormal activity reported in epileptic tissue. Genuine U.S. Federal Reserve Notes have a consistent, two-component intrinsic fluorescence lifetime. This allows for detection of counterfeit paper money because of its significant differences in fluorescence lifetime when compared to genuine paper money. We used

  5. Determining the Spectral Content of MOSES Images

    NASA Astrophysics Data System (ADS)

    Parker, Jacob; Kankelborg, Charles

    2016-05-01

    The MOSES (Multi-Order Solar EUV Spectrograph) sounding rocket was launched February 8th, 2006. The MOSES concave grating forms solar images in multiple spectral orders, in an effort to measure line profiles from a single exposure over a wide field of view. We present a preliminary identification of spectral content in MOSES images. The cross correlation of subtracted images provide evidence of spectral content besides the normal 304 Anstrom He II line. We place confidence on the peaks in correlation by cross correlating random data that is statistically representative of MOSES data. These significant peaks indicate a contribution to intensity from several coronal lines. These lines are individually weak, but if not taken into account, they would significantly increase the residuals when inverting MOSES images to obtain spectra.

  6. Multiphoton adaptation of a commercial low-cost confocal microscope for live tissue imaging

    NASA Astrophysics Data System (ADS)

    Mancuso, James J.; Larson, Adam M.; Wensel, Theodore G.; Saggau, Peter

    2009-05-01

    The Nikon C1 confocal laser scanning microscope is a relatively inexpensive and user-friendly instrument. We describe a straightforward method to convert the C1 for multiphoton microscopy utilizing direct coupling of a femtosecond near-infrared laser into the scan head and fiber optic transmission of emission light to the three-channel detector box. Our adapted system can be rapidly switched between confocal and multiphoton mode, requires no modification to the original system, and uses only a few custom-made parts. The entire system, including scan mirrors and detector box, remain under the control of the user-friendly Nikon EZ-C1 software without modification.

  7. Spectrally resolved multidepth fluorescence imaging

    PubMed Central

    Luo, Yuan; Zervantonakis, Ioannis K.; Oh, Se Baek; Kamm, Roger D.; Barbastathis, George

    2011-01-01

    We present a multicolor fluorescence imaging modality to visualize in real-time tissue structures emitting multispectral fluorescent light from different focal depths. Each designated spectrum of fluorescent emission from a specific depth within a volumetric tissue is probed by a depth-spectrum selective holographic grating. The grating for each fluorescent color are multiplexed within a volume hologram, which enables simultaneously obtaining multicolored fluorescent information at different depths within a biological tissue sample. We demonstrate the imaging modality's ability to obtain laser-induced multicolored fluorescence images of a biological sample from different depths without scanning. We also experimentally demonstrate that the imaging modality can be simultaneously operated at both fluorescent and bright field modes to provide complementary information of volumetric tissue structures at different depths in real-time. PMID:21950929

  8. Spectrally resolved multidepth fluorescence imaging

    NASA Astrophysics Data System (ADS)

    Luo, Yuan; Zervantonakis, Ioannis K.; Oh, Se Baek; Kamm, Roger D.; Barbastathis, George

    2011-09-01

    We present a multicolor fluorescence imaging modality to visualize in real-time tissue structures emitting multispectral fluorescent light from different focal depths. Each designated spectrum of fluorescent emission from a specific depth within a volumetric tissue is probed by a depth-spectrum selective holographic grating. The grating for each fluorescent color are multiplexed within a volume hologram, which enables simultaneously obtaining multicolored fluorescent information at different depths within a biological tissue sample. We demonstrate the imaging modality's ability to obtain laser-induced multicolored fluorescence images of a biological sample from different depths without scanning. We also experimentally demonstrate that the imaging modality can be simultaneously operated at both fluorescent and bright field modes to provide complementary information of volumetric tissue structures at different depths in real-time.

  9. Label free multiphoton imaging of human pulmonary tissues through two-meter-long microstructured fiber and multicore image-guide

    NASA Astrophysics Data System (ADS)

    Ducourthial, G.; Lefort, C.; Peyrot, D. A.; Mansuryan, T.; Kruglik, S. G.; Vever-Bizet, C.; Thiberville, L.; Lacombe, F.; Bourg-Heckly, Geneviève; Louradour, Frédéric

    2013-03-01

    This work deals with label free multiphoton imaging of the human lung tissue extra-cellular matrix (ECM) through optical fibers. Two devices were developed, the first one using distal scanning associated to a double clad large mode area (LMA) air-silica microstructured fiber, the second one using proximal scanning of a miniature multicore image guide (30000 cores inside a 0.8 mm diameter). In both cases, the main issue has been efficient linear and nonlinear distortion pre-compensation of excitation pulses. By inserting before the delivery fiber a compact (10 cm × 10 cm footprint) grisms-based stretcher (a grating in close contact with a prism) made of readily available commercial components, we achieved as short as 35-femtosecond-duration pulses that were temporally compressed at the direct exit of a 2-meter-long fiber. Interestingly, this femtosecond pulse fiber delivery device is also wavelength tunable over more than 100 nm inside the Ti: Sapphire emission band. With the help of distal scan system, those unique features allowed us to record elastin (through two-photon fluorescence) and collagen (through second harmonic generation) fibered network images. These images were obtained ex-vivo with only 15 mW @ 80 MHz of IR radiation delivered to the alveoli or bronchus tissues. 3D imaging with 400-μm-penetration depth inside the tissue was possible working with a 2-meter-long LMA fiber. With the help of proximal scanning, the miniature image guide allowed us to perform endoscopic real time microimaging of the ECM ex vivo.

  10. Information-efficient spectral imaging sensor

    DOEpatents

    Sweatt, William C.; Gentry, Stephen M.; Boye, Clinton A.; Grotbeck, Carter L.; Stallard, Brian R.; Descour, Michael R.

    2003-01-01

    A programmable optical filter for use in multispectral and hyperspectral imaging. The filter splits the light collected by an optical telescope into two channels for each of the pixels in a row in a scanned image, one channel to handle the positive elements of a spectral basis filter and one for the negative elements of the spectral basis filter. Each channel for each pixel disperses its light into n spectral bins, with the light in each bin being attenuated in accordance with the value of the associated positive or negative element of the spectral basis vector. The spectral basis vector is constructed so that its positive elements emphasize the presence of a target and its negative elements emphasize the presence of the constituents of the background of the imaged scene. The attenuated light in the channels is re-imaged onto separate detectors for each pixel and then the signals from the detectors are combined to give an indication of the presence or not of the target in each pixel of the scanned scene. This system provides for a very efficient optical determination of the presence of the target, as opposed to the very data intensive data manipulations that are required in conventional hyperspectral imaging systems.

  11. Multi Spectral Fluorescence Imager (MSFI)

    NASA Technical Reports Server (NTRS)

    Caron, Allison

    2016-01-01

    Genetic transformation with in vivo reporter genes for fluorescent proteins can be performed on a variety of organisms to address fundamental biological questions. Model organisms that may utilize an ISS imager include unicellular organisms (Saccharomyces cerevisiae), plants (Arabidopsis thaliana), and invertebrates (Caenorhabditis elegans). The multispectral fluorescence imager (MSFI) will have the capability to accommodate 10 cm x 10 cm Petri plates, various sized multi-well culture plates, and other custom culture containers. Features will include programmable temperature and light cycles, ethylene scrubbing (less than 25 ppb), CO2 control (between 400 ppm and ISS-ambient levels in units of 100 ppm) and sufficient airflow to prevent condensation that would interfere with imaging.

  12. Multiphoton tomography of intratissue tattoo nanoparticles

    NASA Astrophysics Data System (ADS)

    König, Karsten

    2012-02-01

    Most of today's intratissue tattoo pigments are unknown nanoparticles. So far, there was no real control of their use due to the absence of regulations. Some of the tattoo pigments contain carcinogenic amines e.g. azo pigment Red 22. Nowadays, the European Union starts to control the administration of tattoo pigments. There is an interest to obtain information on the intratissue distribution, their interaction with living cells and the extracellular matrix, and the mechanisms behind laser tattoo removal. Multiphoton tomographs are novel biosafety and imaging tools that can provide such information non-invasively and without further labeling. When using the spectral FLIM module, spatially-resolved emission spectra, excitation spectra, and fluorescence lifetimes can pr provided. Multiphoton tomographs are used by all major cosmetic comapanies to test the biosafety of sunscreen nanoparticles.

  13. 3D-spectral domain computational imaging

    NASA Astrophysics Data System (ADS)

    Anderson, Trevor; Segref, Armin; Frisken, Grant; Ferra, Herman; Lorenser, Dirk; Frisken, Steven

    2016-03-01

    We present a proof-of-concept experiment utilizing a novel "snap-shot" spectral domain OCT technique that captures a phase coherent volume in a single frame. The sample is illuminated with a collimated beam of 75 μm diameter and the back-reflected light is analyzed by a 2-D matrix of spectral interferograms. A key challenge that is addressed is simultaneously maintaining lateral and spectral phase coherence over the imaged volume in the presence of sample motion. Digital focusing is demonstrated for 5.0 μm lateral resolution over an 800 μm axial range.

  14. MULTIPHOTON PROCESSES

    SciTech Connect

    2002-07-05

    The Gordon Research Conference (GRC) on MULTIPHOTON PROCESSES was held at Tilton School, Tilton, NH. Emphasis was placed on current unpublished research and discussion of the future target areas in this field.

  15. Label-free imaging of goblet cells as a marker for differentiating colonic polyps by multiphoton microscopy Label-free imaging of goblet cells

    NASA Astrophysics Data System (ADS)

    Zhuo, S. M.; Wu, G. Z.; Chen, J. X.; Zhu, X. Q.; Xie, S. S.

    2012-06-01

    Discrimination of adenomas from hyperplastic polyps can reduce the risk of unnecessary complications and healthcare cost. However, it is challenging during colonoscopy screening, and histological analysis remains the ``gold standard'' for the final diagnosis. Here, we describe a label-free imaging method, multiphoton microscopy (MPM), to the discrimination between adenomas and hyperplastic polyps. We find that multiphoton imaging provides cellular and subcellular details to the identification of adenomas from hyperplastic polyps. In particular, there is significant difference in the population density of goblet cells among normal colon, hyperplastic polyp, and adenoma, providing substantial potential to become a quantitative intrinsic marker for in vivo clinical diagnosis of early colonic lesions. To our knowledge, this is the first demonstration of the potential of MPM for differentiation of colonic polyps.

  16. Calibration and characterization of spectral imaging systems

    NASA Astrophysics Data System (ADS)

    Polder, Gerrit; van der Heijden, Gerie W.

    2001-09-01

    Spectral image sensors provide images with a large umber of contiguous spectral channels per pixel. This paper describes the calibration of spectrograph based spectral imaging systems. The relation between pixel position and measured wavelength was determined using three different wavelength calibration sources. Results indicate that for spectral calibration a source with very small peaks,such as a HgAr source, is preferred to arrow band filters. A second order polynomial model gives a better fit than a linear model for the pixel to wavelength mapping. The signal to noise ratio (SNR)is determined per wavelength. In the blue part of the spectrum,the SNR was lower than in the green and red part.This is due to a decreased quantum efficiency of the CCD,a smaller transmission coefficient of the spectrograph,as well as poor performance of the illuminant. Increasing the amount of blue light,using additional Fluorescent tube with special coating increased the SNR considerably. Furthermore, the spatial and spectral resolution of the system are determined.These can be used to choose appropriate binning factors to decrease the image size without losing information.

  17. Dynamical Spectral Unmixing of Multitemporal Hyperspectral Images

    NASA Astrophysics Data System (ADS)

    Henrot, Simon; Chanussot, Jocelyn; Jutten, Christian

    2016-07-01

    In this paper, we consider the problem of unmixing a time series of hyperspectral images. We propose a dynamical model based on linear mixing processes at each time instant. The spectral signatures and fractional abundances of the pure materials in the scene are seen as latent variables, and assumed to follow a general dynamical structure. Based on a simplified version of this model, we derive an efficient spectral unmixing algorithm to estimate the latent variables by performing alternating minimizations. The performance of the proposed approach is demonstrated on synthetic and real multitemporal hyperspectral images.

  18. Remote Sensing of Landscapes with Spectral Images

    NASA Astrophysics Data System (ADS)

    Adams, John B.; Gillespie, Alan R.

    2006-05-01

    Remote Sensing of Landscapes with Spectral Images describes how to process and interpret spectral images using physical models to bridge the gap between the engineering and theoretical sides of remote-sensing and the world that we encounter when we venture outdoors. The emphasis is on the practical use of images rather than on theory and mathematical derivations. Examples are drawn from a variety of landscapes and interpretations are tested against the reality seen on the ground. The reader is led through analysis of real images (using figures and explanations); the examples are chosen to illustrate important aspects of the analytic framework. This textbook will form a valuable reference for graduate students and professionals in a variety of disciplines including ecology, forestry, geology, geography, urban planning, archeology and civil engineering. It is supplemented by a web-site hosting digital color versions of figures in the book as well as ancillary images (www.cambridge.org/9780521662214). Presents a coherent view of practical remote sensing, leading from imaging and field work to the generation of useful thematic maps Explains how to apply physical models to help interpret spectral images Supplemented by a website hosting digital colour versions of figures in the book, as well as additional colour figures

  19. Label-free multi-photon imaging using a compact femtosecond fiber laser mode-locked by carbon nanotube saturable absorber

    PubMed Central

    Kieu, K.; Mehravar, S.; Gowda, R.; Norwood, R. A.; Peyghambarian, N.

    2013-01-01

    We demonstrate label-free multi-photon imaging of biological samples using a compact Er3+-doped femtosecond fiber laser mode-locked by a single-walled carbon nanotube (CNT). These compact and low cost lasers have been developed by various groups but they have not been exploited for multiphoton microscopy. Here, it is shown that various multiphoton imaging modalities (e.g. second harmonic generation (SHG), third harmonic generation (THG), two-photon excitation fluorescence (TPEF), and three-photon excitation fluorescence (3PEF)) can be effectively performed on various biological samples using a compact handheld CNT mode-locked femtosecond fiber laser operating in the telecommunication window near 1560nm. We also show for the first time that chlorophyll fluorescence in plant leaves and diatoms can be observed using 1560nm laser excitation via three-photon absorption. PMID:24156074

  20. Miniaturized spectral imager for Aalto-1 nanosatellite

    NASA Astrophysics Data System (ADS)

    Mannila, Rami; Näsilä, Antti; Praks, Jaan; Saari, Heikki; Antila, Jarkko

    2011-11-01

    The Aalto-1 is a 3U-cubesat project coordinated by Aalto University. The satellite, Aalto-1, will be mainly built by students as project assignments and thesis works. VTT Technical Research Centre of Finland will develop the main Earth observation payload, a miniaturized spectral imager, for the satellite. It is a novel highly miniaturized tunable filter type spectral imager. Mass of the spectral imager will be less than 400 grams, and dimensions will be approximately 80 mm x 80 mm x 45 mm. The spectral imager is based on a tunable Fabry-Pérot interferometer (FPI) accompanied by an RGB CMOS image sensor. The FPI consists of two highly reflective surfaces separated by a tunable air gap and it is based either on a microelectromechanical (MEMS) or piezo-actuated structure. The MEMS FPI is a monolithic device, i.e. it is made entirely on one substrate in a batch process, without assembling separate pieces together. The gap is adjusted by moving the upper mirror with electrostatic force. Benefits of the MEMS FPI are low mass and small size. However, large aperture (2-10 mm) MEMS FPIs are currently under development, thus it is not yet known if their performance is adequate. The piezo-actuated FPI uses three piezo-actuators and is controlled in a closed capacitive feedback loop. The drawback of the piezo-actuated FPI is its higher mass. However, it has a large aperture which enables a shorter exposure times. Selection of the FPI type will be done after thorough evaluation. Depending on the selected FPI type, the spectral resolution of the imager will be 5 - 10 nm at full width at half maximum and it will operate in the visible and/or near infrared range.

  1. Multi-spectral imaging of oxygen saturation

    NASA Astrophysics Data System (ADS)

    Savelieva, Tatiana A.; Stratonnikov, Aleksander A.; Loschenov, Victor B.

    2008-06-01

    The system of multi-spectral imaging of oxygen saturation is an instrument that can record both spectral and spatial information about a sample. In this project, the spectral imaging technique is used for monitoring of oxygen saturation of hemoglobin in human tissues. This system can be used for monitoring spatial distribution of oxygen saturation in photodynamic therapy, surgery or sports medicine. Diffuse reflectance spectroscopy in the visible range is an effective and extensively used technique for the non-invasive study and characterization of various biological tissues. In this article, a short review of modeling techniques being currently in use for diffuse reflection from semi-infinite turbid media is presented. A simple and practical model for use with a real-time imaging system is proposed. This model is based on linear approximation of the dependence of the diffuse reflectance coefficient on relation between absorbance and reduced scattering coefficient. This dependence was obtained with the Monte Carlo simulation of photon propagation in turbid media. Spectra of the oxygenated and deoxygenated forms of hemoglobin differ mostly in the red area (520 - 600 nm) and have several characteristic points there. Thus four band-pass filters were used for multi-spectral imaging. After having measured the reflectance, the data obtained are used for fitting the concentration of oxygenated and free hemoglobin, and hemoglobin oxygen saturation.

  2. Multi-photon Intracellular Sodium Imaging Combined with UV-mediated Focal Uncaging of Glutamate in CA1 Pyramidal Neurons

    PubMed Central

    Rose, Christine R.

    2014-01-01

    Multi-photon fluorescence microscopy has enabled the analysis of morphological and physiological parameters of brain cells in the intact tissue with high spatial and temporal resolution. Combined with electrophysiology, it is widely used to study activity-related calcium signals in small subcellular compartments such as dendrites and dendritic spines. In addition to calcium transients, synaptic activity also induces postsynaptic sodium signals, the properties of which are only marginally understood. Here, we describe a method for combined whole-cell patch-clamp and multi-photon sodium imaging in cellular micro domains of central neurons. Furthermore, we introduce a modified procedure for ultra-violet (UV)-light-induced uncaging of glutamate, which allows reliable and focal activation of glutamate receptors in the tissue. To this end, whole-cell recordings were performed on Cornu Ammonis subdivision 1 (CA1) pyramidal neurons in acute tissue slices of the mouse hippocampus. Neurons were filled with the sodium-sensitive fluorescent dye SBFI through the patch-pipette, and multi-photon excitation of SBFI enabled the visualization of dendrites and adjacent spines. To establish UV-induced focal uncaging, several parameters including light intensity, volume affected by the UV uncaging beam, positioning of the beam as well as concentration of the caged compound were tested and optimized. Our results show that local perfusion with caged glutamate (MNI-Glutamate) and its focal UV-uncaging result in inward currents and sodium transients in dendrites and spines. Time course and amplitude of both inward currents and sodium signals correlate with the duration of the uncaging pulse. Furthermore, our results show that intracellular sodium signals are blocked in the presence of blockers for ionotropic glutamate receptors, demonstrating that they are mediated by sodium influx though this pathway. In summary, our method provides a reliable tool for the investigation of intracellular

  3. Integrated spectrometer design with application to multiphoton microscopy.

    PubMed

    Chandler, Eric V; Durfee, Charles G; Squier, Jeffrey A

    2011-01-01

    We present a prism-based spectrometer integrated into a multifocal, multiphoton microscope. The multifocal configuration facilitates interrogation of samples under different excitation conditions. Notably, the image plane of the microscope and the image plane of the spectrometer are coincident eliminating the need for an intermediate image plane containing an entrance slit. An EM-CCD detector provides sufficient gain for spectral interrogation of single-emitters. We employ this spectrometer to observe spectral shifts in the two-photon excitation fluorescence emission of single CdSe nanodots as a function of excitation polarization. PMID:21263548

  4. High-fidelity spatially resolved multiphoton counting for quantum imaging applications.

    PubMed

    Chrapkiewicz, Radosław; Wasilewski, Wojciech; Banaszek, Konrad

    2014-09-01

    We present a method for spatially resolved multiphoton counting based on an intensified camera with the retrieval of multimode photon statistics fully accounting for nonlinearities in the detection process. The scheme relies on one-time quantum tomographic calibration of the detector. Faithful, high-fidelity reconstruction of single- and two-mode statistics of multiphoton states is demonstrated for coherent states and their statistical mixtures. The results consistently exhibit classical values of the Mandel parameter and the noise reduction factor in contrast to raw statistics of camera photo-events. Detector operation is reliable for illumination levels up to the average of one detected photon per an event area-substantially higher than in previous approaches to characterize quantum statistical properties of light with spatial resolution. PMID:25166081

  5. Spectral image fusion using band reduction and contourlets

    NASA Astrophysics Data System (ADS)

    Choi, Yoonsuk; Sharifahmadian, Ershad; Latifi, Shahram

    2014-06-01

    Spectral images have relatively low spatial resolution, compared to high-resolution single band panchromatic (PAN) images. Therefore, fusing a spectral image with a PAN image has been widely studied to produce a high-resolution spectral image. However, raw spectral images are too large to process and contain redundant information that is not utilized in the fusion process. In this study, we propose a novel fusion method that employs a spectral band reduction and contourlets. The band reduction begins with the best two band combination, and this two-band combination is subsequently augmented to three, four, and more until the desired number of bands is selected. The adopted band selection algorithm using the endmember extraction concept employs a sequential forward search strategy. Next, the image fusion is performed with two different spectral images based on the frequency components that are newly obtained by contourlet transform (CT). One spectral image that is used as a dataset is multispectral (MS) image and the other is hyperspectral (HS) image. Each original spectral image is pre-processed by spectrally integrating over the entire spectral range to obtain a PAN source image that is used in the fusion process. This way, we can eliminate the step of image co-registration since the obtained PAN image is already perfectly aligned to the spectral image. Next, we fuse the band-reduced spectral images with the PAN images using contourlet-based fusion framework. The resultant fusion image provides enhanced spatial resolution while preserving the spectral information. In order to analyze the band reduction performance, the original spectral images are fused with the same PAN images to serve as a reference image, which is then compared to the band-reduced spectral image fusion results using six different quality metrics.

  6. Pulse front adaptive optics in multiphoton microscopy

    NASA Astrophysics Data System (ADS)

    Sun, B.; Salter, P. S.; Booth, M. J.

    2016-03-01

    The accurate focusing of ultrashort laser pulses is extremely important in multiphoton microscopy. Using adaptive optics to manipulate the incident ultrafast beam in either the spectral or spatial domain can introduce significant benefits when imaging. Here we introduce pulse front adaptive optics: manipulating an ultrashort pulse in both the spatial and temporal domains. A deformable mirror and a spatial light modulator are operated in concert to modify contours of constant intensity in space and time within an ultrashort pulse. Through adaptive control of the pulse front, we demonstrate an enhancement in the measured fluorescence from a two photon microscope.

  7. From morphology to biochemical state – intravital multiphoton fluorescence lifetime imaging of inflamed human skin

    PubMed Central

    Huck, Volker; Gorzelanny, Christian; Thomas, Kai; Getova, Valentina; Niemeyer, Verena; Zens, Katharina; Unnerstall, Tim R.; Feger, Julia S.; Fallah, Mohammad A.; Metze, Dieter; Ständer, Sonja; Luger, Thomas A.; Koenig, Karsten; Mess, Christian; Schneider, Stefan W.

    2016-01-01

    The application of multiphoton microscopy in the field of biomedical research and advanced diagnostics promises unique insights into the pathophysiology of inflammatory skin diseases. In the present study, we combined multiphoton-based intravital tomography (MPT) and fluorescence lifetime imaging (MPT-FLIM) within the scope of a clinical trial of atopic dermatitis with the aim of providing personalised data on the aetiopathology of inflammation in a non-invasive manner at patients’ bedsides. These ‘optical biopsies’ generated via MPT were morphologically analysed and aligned with classical skin histology. Because of its subcellular resolution, MPT provided evidence of a redistribution of mitochondria in keratinocytes, indicating an altered cellular metabolism. Two independent morphometric algorithms reliably showed an even distribution in healthy skin and a perinuclear accumulation in inflamed skin. Moreover, using MPT-FLIM, detection of the onset and progression of inflammatory processes could be achieved. In conclusion, the change in the distribution of mitochondria upon inflammation and the verification of an altered cellular metabolism facilitate a better understanding of inflammatory skin diseases and may permit early diagnosis and therapy. PMID:27004454

  8. From morphology to biochemical state – intravital multiphoton fluorescence lifetime imaging of inflamed human skin

    NASA Astrophysics Data System (ADS)

    Huck, Volker; Gorzelanny, Christian; Thomas, Kai; Getova, Valentina; Niemeyer, Verena; Zens, Katharina; Unnerstall, Tim R.; Feger, Julia S.; Fallah, Mohammad A.; Metze, Dieter; Ständer, Sonja; Luger, Thomas A.; Koenig, Karsten; Mess, Christian; Schneider, Stefan W.

    2016-03-01

    The application of multiphoton microscopy in the field of biomedical research and advanced diagnostics promises unique insights into the pathophysiology of inflammatory skin diseases. In the present study, we combined multiphoton-based intravital tomography (MPT) and fluorescence lifetime imaging (MPT-FLIM) within the scope of a clinical trial of atopic dermatitis with the aim of providing personalised data on the aetiopathology of inflammation in a non-invasive manner at patients’ bedsides. These ‘optical biopsies’ generated via MPT were morphologically analysed and aligned with classical skin histology. Because of its subcellular resolution, MPT provided evidence of a redistribution of mitochondria in keratinocytes, indicating an altered cellular metabolism. Two independent morphometric algorithms reliably showed an even distribution in healthy skin and a perinuclear accumulation in inflamed skin. Moreover, using MPT-FLIM, detection of the onset and progression of inflammatory processes could be achieved. In conclusion, the change in the distribution of mitochondria upon inflammation and the verification of an altered cellular metabolism facilitate a better understanding of inflammatory skin diseases and may permit early diagnosis and therapy.

  9. Multiphoton microscopic imaging of histological sections without hematoxylin and eosin staining differentiates carcinoma in situ lesion from normal oesophagus

    NASA Astrophysics Data System (ADS)

    Chen, Jianxin; Xu, Jian; Kang, Deyong; Xu, Meifang; Zhuo, Shuangmu; Zhu, Xiaoqin; Jiang, Xingshan

    2013-10-01

    Multiphoton microscopy (MPM) has become a powerful, important tool for tissues imaging at the molecular level. In this paper, this technique was extended to histological investigations, differentiating carcinoma in situ (CIS) lesion from normal oesophagus by imaging histological sections without hematoxylin and eosin (H&E) staining. The results show that the histology procedures of dehydration, paraffin embedding, and de-paraffinizing highlighted two photon excited fluorescence of cytoplasm and nucleolus of epithelial cell and collagen in stroma. MPM has the ability to identify the characteristics of CIS lesion including changes of squamous cells and full epithelium, identification of basement membrane, especially prominent nucleolus. The studies described here show that MPM has the potential for future retrospective studies of tumor staging by employing on histological section specimens without H&E staining.

  10. CALIBRATION AND VALIDATION OF CONFOCAL SPECTRAL IMAGING SYSTEMS

    EPA Science Inventory

    Confocal spectral imaging (CSI) microscope systems now on the market can perform spectral characterization of biological specimens containing fluorescent proteins, labels or dyes. Some CSI have been found to present inconsistent spectral characterizations within a particular syst...

  11. WAVELENGTH AND ALIGNMENT TESTS FOR CONFOCAL SPECTRAL IMAGING SYSTEMS

    EPA Science Inventory

    Confocal spectral imaging (CSI) microscope systems now on the market delineate multiple fluorescent proteins, labels, or dyes within biological specimens by performing spectral characterizations. However, we find that some CSI present inconsistent spectral profiles of reference s...

  12. The spectral imaging facility: Setup characterization

    SciTech Connect

    De Angelis, Simone De Sanctis, Maria Cristina; Manzari, Paola Olga; Ammannito, Eleonora; Di Iorio, Tatiana; Liberati, Fabrizio; Tarchi, Fabio; Dami, Michele; Olivieri, Monica; Pompei, Carlo; Mugnuolo, Raffaele

    2015-09-15

    The SPectral IMager (SPIM) facility is a laboratory visible infrared spectrometer developed to support space borne observations of rocky bodies of the solar system. Currently, this laboratory setup is used to support the DAWN mission, which is in its journey towards the asteroid 1-Ceres, and to support the 2018 Exo-Mars mission in the spectral investigation of the Martian subsurface. The main part of this setup is an imaging spectrometer that is a spare of the DAWN visible infrared spectrometer. The spectrometer has been assembled and calibrated at Selex ES and then installed in the facility developed at the INAF-IAPS laboratory in Rome. The goal of SPIM is to collect data to build spectral libraries for the interpretation of the space borne and in situ hyperspectral measurements of planetary materials. Given its very high spatial resolution combined with the imaging capability, this instrument can also help in the detailed study of minerals and rocks. In this paper, the instrument setup is first described, and then a series of test measurements, aimed to the characterization of the main subsystems, are reported. In particular, laboratory tests have been performed concerning (i) the radiation sources, (ii) the reference targets, and (iii) linearity of detector response; the instrumental imaging artifacts have also been investigated.

  13. The spectral imaging facility: Setup characterization.

    PubMed

    De Angelis, Simone; Ammannito, Eleonora; Di Iorio, Tatiana; De Sanctis, Maria Cristina; Manzari, Paola Olga; Liberati, Fabrizio; Tarchi, Fabio; Dami, Michele; Olivieri, Monica; Pompei, Carlo; Mugnuolo, Raffaele

    2015-09-01

    The SPectral IMager (SPIM) facility is a laboratory visible infrared spectrometer developed to support space borne observations of rocky bodies of the solar system. Currently, this laboratory setup is used to support the DAWN mission, which is in its journey towards the asteroid 1-Ceres, and to support the 2018 Exo-Mars mission in the spectral investigation of the Martian subsurface. The main part of this setup is an imaging spectrometer that is a spare of the DAWN visible infrared spectrometer. The spectrometer has been assembled and calibrated at Selex ES and then installed in the facility developed at the INAF-IAPS laboratory in Rome. The goal of SPIM is to collect data to build spectral libraries for the interpretation of the space borne and in situ hyperspectral measurements of planetary materials. Given its very high spatial resolution combined with the imaging capability, this instrument can also help in the detailed study of minerals and rocks. In this paper, the instrument setup is first described, and then a series of test measurements, aimed to the characterization of the main subsystems, are reported. In particular, laboratory tests have been performed concerning (i) the radiation sources, (ii) the reference targets, and (iii) linearity of detector response; the instrumental imaging artifacts have also been investigated. PMID:26429423

  14. The spectral imaging facility: Setup characterization

    NASA Astrophysics Data System (ADS)

    De Angelis, Simone; Ammannito, Eleonora; Di Iorio, Tatiana; De Sanctis, Maria Cristina; Manzari, Paola Olga; Liberati, Fabrizio; Tarchi, Fabio; Dami, Michele; Olivieri, Monica; Pompei, Carlo; Mugnuolo, Raffaele

    2015-09-01

    The SPectral IMager (SPIM) facility is a laboratory visible infrared spectrometer developed to support space borne observations of rocky bodies of the solar system. Currently, this laboratory setup is used to support the DAWN mission, which is in its journey towards the asteroid 1-Ceres, and to support the 2018 Exo-Mars mission in the spectral investigation of the Martian subsurface. The main part of this setup is an imaging spectrometer that is a spare of the DAWN visible infrared spectrometer. The spectrometer has been assembled and calibrated at Selex ES and then installed in the facility developed at the INAF-IAPS laboratory in Rome. The goal of SPIM is to collect data to build spectral libraries for the interpretation of the space borne and in situ hyperspectral measurements of planetary materials. Given its very high spatial resolution combined with the imaging capability, this instrument can also help in the detailed study of minerals and rocks. In this paper, the instrument setup is first described, and then a series of test measurements, aimed to the characterization of the main subsystems, are reported. In particular, laboratory tests have been performed concerning (i) the radiation sources, (ii) the reference targets, and (iii) linearity of detector response; the instrumental imaging artifacts have also been investigated.

  15. Automated eXpert Spectral Image Analysis

    Energy Science and Technology Software Center (ESTSC)

    2003-11-25

    AXSIA performs automated factor analysis of hyperspectral images. In such images, a complete spectrum is collected an each point in a 1-, 2- or 3- dimensional spatial array. One of the remaining obstacles to adopting these techniques for routine use is the difficulty of reducing the vast quantities of raw spectral data to meaningful information. Multivariate factor analysis techniques have proven effective for extracting the essential information from high dimensional data sets into a limtedmore » number of factors that describe the spectral characteristics and spatial distributions of the pure components comprising the sample. AXSIA provides tools to estimate different types of factor models including Singular Value Decomposition (SVD), Principal Component Analysis (PCA), PCA with factor rotation, and Alternating Least Squares-based Multivariate Curve Resolution (MCR-ALS). As part of the analysis process, AXSIA can automatically estimate the number of pure components that comprise the data and can scale the data to account for Poisson noise. The data analysis methods are fundamentally based on eigenanalysis of the data crossproduct matrix coupled with orthogonal eigenvector rotation and constrained alternating least squares refinement. A novel method for automatically determining the number of significant components, which is based on the eigenvalues of the crossproduct matrix, has also been devised and implemented. The data can be compressed spectrally via PCA and spatially through wavelet transforms, and algorithms have been developed that perform factor analysis in the transform domain while retaining full spatial and spectral resolution in the final result. These latter innovations enable the analysis of larger-than core-memory spectrum-images. AXSIA was designed to perform automated chemical phase analysis of spectrum-images acquired by a variety of chemical imaging techniques. Successful applications include Energy Dispersive X-ray Spectroscopy, X

  16. Multicolor multiphoton microscopy based on a nanosecond supercontinuum laser source.

    PubMed

    Lefort, Claire; O'Connor, Rodney P; Blanquet, Véronique; Magnol, Laetitia; Kano, Hideaki; Tombelaine, Vincent; Lévêque, Philippe; Couderc, Vincent; Leproux, Philippe

    2016-07-01

    Multicolor multiphoton microscopy is experimentally demonstrated for the first time on a spectral bandwidth of excitation of 300 nm (full width half maximum) thanks to the implementation a nanosecond supercontinuum (SC) source compact and simple with a low repetition rate. The interest of such a wide spectral bandwidth, never demonstrated until now, is highlighted in vivo: images of glioma tumor cells stably expressing eGFP grafted on the brain of a mouse and its blood vessels network labelled with Texas Red(®) are obtained. These two fluorophores have a spectral bandwidth covering the whole 300 nm available. In parallel, a similar image quality is obtained on a sample of mouse muscle in vitro when excited with this nanosecond SC source or with a classical high rate, femtosecond and quasi monochromatic laser. This opens the way for (i) a simple and very complete biological characterization never performed to date with multiphoton processes, (ii) multiple means of contrast in nonlinear imaging allowed by the use of numerous fluorophores and (iii) other multiphoton processes like three-photon ones. PMID:26872004

  17. Detection of latent fingerprints by ultraviolet spectral imaging

    NASA Astrophysics Data System (ADS)

    Huang, Wei; Xu, Xiaojing; Wang, Guiqiang

    2013-12-01

    Spectral imaging technology research is becoming more popular in the field of forensic science. Ultraviolet spectral imaging technology is an especial part of the full spectrum of imaging technology. This paper finished the experiment contents of the ultraviolet spectrum imaging method and image acquisition system based on ultraviolet spectral imaging technology. Ultraviolet spectral imaging experiments explores a wide variety of ultraviolet reflectance spectra of the object material curve and its ultraviolet spectrum of imaging modalities, can not only gives a reference for choosing ultraviolet wavelength to show the object surface potential traces of substances, but also gives important data for the ultraviolet spectrum of imaging technology development.

  18. [Microscopic infrared spectral imaging of oily core].

    PubMed

    Huang, Qiao-Song; Yu, Zhao-Xian; Li, Jing; Chen, Chen

    2009-02-01

    In the present paper, the authors examined some oily core by microscopic infrared spectral imaging methods. Those methods can be classified in three modes, referred to as "transmission mode", "reflection mode" and "attenuated total reflection (ATR) mode". The observed oily core samples belong to siltstone. The samples were made of quartz (-20%), feldspar(-50%) and other rock (igneous rock 25%, metamorphic rocks 1%, sedimentary rock 4%); a little recrystallized calcite (-1%) was in the pore, and the argillaceous matter was distributed along the edge of a pore. The experimental work has been accomplished using SHIMADZU Model IRPrestige-21 Fourier transform infrared spectrophotometer plus AIM8800 infrared microscope. For IRPrestige-21, the spectral range is 7 800-350 cm(-1) spectral resolution is 1 cm(-1), and AIM8800 microscope with motorized stages has a resolution of 1 micrometer. The experiment was preformed at room temperature. In "transmission mode" infrared spectral imaging method, the spectral range was limited in wavenumbers greater than 2 000 cm(-1) because the base glass piece has strong light absorption. In contrast with "transmission mode", in "attenuated total reflection (ATR) mode", the depth of penetration into sample is very small (1-2 micrometer), then the absorbance value has nothing to do with base glass piece light absorption. In microscopic infrared transmission spectra, the experimental result shows that there are some strong absorption peaks at 2 866, 2 928, 3 618 and 2 515 cm(-1) respectively. The former two peaks correspond to methyl(methylene) symmetrical and unsymmetrical stretch vibration mode, respectively. The latter two peaks correspond to hydroxyl-stretch vibration mode and S-H, P-H chemical bond stretch vibration mode, respectively. In microscopic longwave infrared ATR spectra, there are other stronger absorption peaks at 1 400, 1 038 and 783 cm(i1)respectively, corresponding to methyl(methylene) widing vibration mode and optical mode

  19. Characterizing collagen-based materials modified by glycation: a multiphoton optical image guided spectroscopy method

    NASA Astrophysics Data System (ADS)

    Hwang, Yu-Jer; Granelli, Joseph; Flores, Christina; Lyubovitsky, Julia

    2011-02-01

    In spite of the adverse ageing effects of glycation in vivo, in vitro this process is widely employed to increase stiffness and strength of tissues' and artificial scaffolds'. In-situ optical characterization methods that report on the structures within these materials could clarify the effects of glycation. We employed one-photon fluorescence and multiphoton microscopy method that combined two-photon fluorescence and second harmonic generation signals to characterize collagen hydrogels modified with glyceraldehyde, ribose and glucose. We observed an increase in the in situ fluorescence as well as structural alterations within the materials during the course of glycation.

  20. Combined multiphoton imaging-pixel analysis for semiquantitation of skin penetration of gold nanoparticles.

    PubMed

    Labouta, Hagar I; Kraus, Tobias; El-Khordagui, Labiba K; Schneider, Marc

    2011-07-15

    Interaction of nanoparticles with the skin barrier is a recent area of research that draws a lot of attention from the researchers. However, monitoring nanoparticles in or through the skin is mainly based on qualitative microscopical techniques. Yet, a quantitative approach is required for a better basic understanding. In response, a combined "multiphoton-pixel analysis" method was developed in this study for semiquantitation of gold nanoparticles penetration into different skin layers. The developed approach provides a useful tool for future studies focusing on skin penetration of nanoparticles for the aim of health risk assessment or for the design of topical and transdermal drug delivery systems. PMID:21515347

  1. Multiphoton imaging to distinguish grana and starch inside an intact leaf

    NASA Astrophysics Data System (ADS)

    Chen, Mei-Yu; Zhuo, Guan-Yu; Chen, Po-Fu; Wu, Pei-Chun; Liu, Tzu-Ming; Chu, Shi-Wei

    2013-02-01

    We have demonstrated a straightforward and noninvasive method to identify the distribution of grana and starch within an intact leaf. Grana and starch are the major functional structures for photosynthesis and energy storage of plant, respectively. Both exhibit highly ordered molecular structures and appear as micrometer-sized granules inside chloroplasts. In order to distinguish grana and starch, we used multiphoton microscopy, with simultaneous acquisition of two photon fluorescence (2PF) and second harmonic generation (SHG) signals. Consequently, SHG is found on both grana and starch while 2PF from chlorophyll indicates the identity of grana.

  2. Clinical multiphoton and CARS microscopy

    NASA Astrophysics Data System (ADS)

    Breunig, H. G.; Weinigel, M.; Darvin, M. E.; Lademann, J.; König, K.

    2012-03-01

    We report on clinical CARS imaging of human skin in vivo with the certified hybrid multiphoton tomograph CARSDermaInspect. The CARS-DermaInspect provides simultaneous imaging of non-fluorescent intradermal lipid and water as well as imaging of two-photon excited fluorescence from intrinsic molecules. Two different excitation schemes for CARS imaging have been realized: In the first setup, a combination of fs oscillator and optical parametric oscillator provided fs-CARS pump and Stokes pulses, respectively. In the second setup a fs oscillator was combined with a photonic crystal fiber which provided a broadband spectrum. A spectral range out of the broadband-spectrum was selected and used for CARS excitation in combination with the residual fs-oscillator output. In both setups, in addition to CARS, single-beam excitation was used for imaging of two-photon excited fluorescence and second harmonic generation signals. Both CARS-excitation systems were successfully used for imaging of lipids inside the skin in vivo.

  3. The design of double electrostatic-lens optics for resonance enhanced multiphoton ionization and photoelectron imaging experiments

    SciTech Connect

    Qu, Zehua; Li, Chunsheng; Qin, Zhengbo E-mail: xfzheng@mail.ahnu.edu.cn; Zheng, Xianfeng E-mail: xfzheng@mail.ahnu.edu.cn; Yao, Guanxin; Zhang, Xianyi; Cui, Zhifeng

    2015-06-15

    Compared to single ion/electron-optics for velocity-map imaging, a double-focusing lens assembly designed not only allows for mapping velocity imaging of photoelectrons but also allows for investigating the vibrational structure of the intermediate states of neutral species in resonance enhanced multiphoton ionization (REMPI) spectra. In this presentation, in order to record REMPI and photoelectron spectra separately, we have constructed a compact photoelectron velocity-map imaging (VMI) apparatus combined with an opposite linear Wiley-Mclaren time-of-flight mass spectrometer (TOFMS). A mass resolution (m/Δm) of ∼1300 for TOFMS and electron energy resolution (ΔE/E) of 2.4% for VMI have been achieved upon three-photon ionization of Xe atom at 258.00 nm laser wavelength. As a benchmark, in combination of one-color (1 + 1) REMPI and photoelectron imaging of benzene via 6{sup 1} and 6{sup 1}1{sup 1} vibronic levels in the S{sub 1} state, the vibrational structures of the cation and photoelectron angular anisotropy are unraveled. In addition, two-color (1 + 1′) REMPI and photoelectron imaging of aniline was used to complete the accurate measurement of ionization potential (62 271 ± 3 cm{sup −1}). The results suggest that the apparatus is a powerful tool for studying photoionization dynamics in the photoelectron imaging using vibrational-state selected excitation to the intermediate states of neutrals based on REMPI technique.

  4. The design of double electrostatic-lens optics for resonance enhanced multiphoton ionization and photoelectron imaging experiments

    NASA Astrophysics Data System (ADS)

    Qu, Zehua; Li, Chunsheng; Qin, Zhengbo; Zheng, Xianfeng; Yao, Guanxin; Zhang, Xianyi; Cui, Zhifeng

    2015-06-01

    Compared to single ion/electron-optics for velocity-map imaging, a double-focusing lens assembly designed not only allows for mapping velocity imaging of photoelectrons but also allows for investigating the vibrational structure of the intermediate states of neutral species in resonance enhanced multiphoton ionization (REMPI) spectra. In this presentation, in order to record REMPI and photoelectron spectra separately, we have constructed a compact photoelectron velocity-map imaging (VMI) apparatus combined with an opposite linear Wiley-Mclaren time-of-flight mass spectrometer (TOFMS). A mass resolution (m/Δm) of ˜1300 for TOFMS and electron energy resolution (ΔE/E) of 2.4% for VMI have been achieved upon three-photon ionization of Xe atom at 258.00 nm laser wavelength. As a benchmark, in combination of one-color (1 + 1) REMPI and photoelectron imaging of benzene via 61 and 6111 vibronic levels in the S1 state, the vibrational structures of the cation and photoelectron angular anisotropy are unraveled. In addition, two-color (1 + 1') REMPI and photoelectron imaging of aniline was used to complete the accurate measurement of ionization potential (62 271 ± 3 cm-1). The results suggest that the apparatus is a powerful tool for studying photoionization dynamics in the photoelectron imaging using vibrational-state selected excitation to the intermediate states of neutrals based on REMPI technique.

  5. The design of double electrostatic-lens optics for resonance enhanced multiphoton ionization and photoelectron imaging experiments.

    PubMed

    Qu, Zehua; Li, Chunsheng; Qin, Zhengbo; Zheng, Xianfeng; Yao, Guanxin; Zhang, Xianyi; Cui, Zhifeng

    2015-06-01

    Compared to single ion/electron-optics for velocity-map imaging, a double-focusing lens assembly designed not only allows for mapping velocity imaging of photoelectrons but also allows for investigating the vibrational structure of the intermediate states of neutral species in resonance enhanced multiphoton ionization (REMPI) spectra. In this presentation, in order to record REMPI and photoelectron spectra separately, we have constructed a compact photoelectron velocity-map imaging (VMI) apparatus combined with an opposite linear Wiley-Mclaren time-of-flight mass spectrometer (TOFMS). A mass resolution (m/Δm) of ∼1300 for TOFMS and electron energy resolution (ΔE/E) of 2.4% for VMI have been achieved upon three-photon ionization of Xe atom at 258.00 nm laser wavelength. As a benchmark, in combination of one-color (1 + 1) REMPI and photoelectron imaging of benzene via 6(1) and 6(1)1(1) vibronic levels in the S1 state, the vibrational structures of the cation and photoelectron angular anisotropy are unraveled. In addition, two-color (1 + 1') REMPI and photoelectron imaging of aniline was used to complete the accurate measurement of ionization potential (62,271 ± 3 cm(-1)). The results suggest that the apparatus is a powerful tool for studying photoionization dynamics in the photoelectron imaging using vibrational-state selected excitation to the intermediate states of neutrals based on REMPI technique. PMID:26133827

  6. In vivo, label-free, three-dimensional quantitative imaging of liver surface using multi-photon microscopy

    SciTech Connect

    Zhuo, Shuangmu E-mail: hanry-yu@nuhs.edu.sg; Yan, Jie; Kang, Yuzhan; Peng, Qiwen; and others

    2014-07-14

    Various structural features on the liver surface reflect functional changes in the liver. The visualization of these surface features with molecular specificity is of particular relevance to understanding the physiology and diseases of the liver. Using multi-photon microscopy (MPM), we have developed a label-free, three-dimensional quantitative and sensitive method to visualize various structural features of liver surface in living rat. MPM could quantitatively image the microstructural features of liver surface with respect to the sinuosity of collagen fiber, the elastic fiber structure, the ratio between elastin and collagen, collagen content, and the metabolic state of the hepatocytes that are correlative with the pathophysiologically induced changes in the regions of interest. This study highlights the potential of this technique as a useful tool for pathophysiological studies and possible diagnosis of the liver diseases with further development.

  7. In vivo, label-free, three-dimensional quantitative imaging of liver surface using multi-photon microscopy

    NASA Astrophysics Data System (ADS)

    Zhuo, Shuangmu; Yan, Jie; Kang, Yuzhan; Xu, Shuoyu; Peng, Qiwen; So, Peter T. C.; Yu, Hanry

    2014-07-01

    Various structural features on the liver surface reflect functional changes in the liver. The visualization of these surface features with molecular specificity is of particular relevance to understanding the physiology and diseases of the liver. Using multi-photon microscopy (MPM), we have developed a label-free, three-dimensional quantitative and sensitive method to visualize various structural features of liver surface in living rat. MPM could quantitatively image the microstructural features of liver surface with respect to the sinuosity of collagen fiber, the elastic fiber structure, the ratio between elastin and collagen, collagen content, and the metabolic state of the hepatocytes that are correlative with the pathophysiologically induced changes in the regions of interest. This study highlights the potential of this technique as a useful tool for pathophysiological studies and possible diagnosis of the liver diseases with further development.

  8. Distinguishing human normal or cancerous esophagus tissue ex vivo using multiphoton microscopy

    NASA Astrophysics Data System (ADS)

    Liu, N. R.; Chen, G. N.; Wu, S. S.; Chen, R.

    2014-02-01

    Application of multiphoton microscopy (MPM) to clinical cancer research has greatly developed over the last few years. In this paper, we mainly focus on two-photon excitation fluorescence (TPEF) and second harmonic generation (SHG) for investigating esophageal cancer. We chiefly discuss the SHG/TPEF image and spectral characteristics of normal and cancerous esophagus submucosa with the combined multi-channel imaging mode and Lambda mode of a multiphoton microscope (LSM 510 META). Great differences can be detected, such as collagen content and morphology, glandular-shaped cancer cells, TPEF/SHG intensity ratio, and so on, which demonstrate that the multiphoton imaging technique has the potential ability for minimally-invasive early cancer diagnosis.

  9. Ultrafast Imaging using Spectral Resonance Modulation

    NASA Astrophysics Data System (ADS)

    Huang, Eric; Ma, Qian; Liu, Zhaowei

    2016-04-01

    CCD cameras are ubiquitous in research labs, industry, and hospitals for a huge variety of applications, but there are many dynamic processes in nature that unfold too quickly to be captured. Although tradeoffs can be made between exposure time, sensitivity, and area of interest, ultimately the speed limit of a CCD camera is constrained by the electronic readout rate of the sensors. One potential way to improve the imaging speed is with compressive sensing (CS), a technique that allows for a reduction in the number of measurements needed to record an image. However, most CS imaging methods require spatial light modulators (SLMs), which are subject to mechanical speed limitations. Here, we demonstrate an etalon array based SLM without any moving elements that is unconstrained by either mechanical or electronic speed limitations. This novel spectral resonance modulator (SRM) shows great potential in an ultrafast compressive single pixel camera.

  10. Ultrafast Imaging using Spectral Resonance Modulation.

    PubMed

    Huang, Eric; Ma, Qian; Liu, Zhaowei

    2016-01-01

    CCD cameras are ubiquitous in research labs, industry, and hospitals for a huge variety of applications, but there are many dynamic processes in nature that unfold too quickly to be captured. Although tradeoffs can be made between exposure time, sensitivity, and area of interest, ultimately the speed limit of a CCD camera is constrained by the electronic readout rate of the sensors. One potential way to improve the imaging speed is with compressive sensing (CS), a technique that allows for a reduction in the number of measurements needed to record an image. However, most CS imaging methods require spatial light modulators (SLMs), which are subject to mechanical speed limitations. Here, we demonstrate an etalon array based SLM without any moving elements that is unconstrained by either mechanical or electronic speed limitations. This novel spectral resonance modulator (SRM) shows great potential in an ultrafast compressive single pixel camera. PMID:27122101

  11. Ultrafast Imaging using Spectral Resonance Modulation

    PubMed Central

    Huang, Eric; Ma, Qian; Liu, Zhaowei

    2016-01-01

    CCD cameras are ubiquitous in research labs, industry, and hospitals for a huge variety of applications, but there are many dynamic processes in nature that unfold too quickly to be captured. Although tradeoffs can be made between exposure time, sensitivity, and area of interest, ultimately the speed limit of a CCD camera is constrained by the electronic readout rate of the sensors. One potential way to improve the imaging speed is with compressive sensing (CS), a technique that allows for a reduction in the number of measurements needed to record an image. However, most CS imaging methods require spatial light modulators (SLMs), which are subject to mechanical speed limitations. Here, we demonstrate an etalon array based SLM without any moving elements that is unconstrained by either mechanical or electronic speed limitations. This novel spectral resonance modulator (SRM) shows great potential in an ultrafast compressive single pixel camera. PMID:27122101

  12. Measurement dimensions compressed spectral imaging with a single point detector

    NASA Astrophysics Data System (ADS)

    Liu, Xue-Feng; Yu, Wen-Kai; Yao, Xu-Ri; Dai, Bin; Li, Long-Zhen; Wang, Chao; Zhai, Guang-Jie

    2016-04-01

    An experimental demonstration of spectral imaging with measurement dimensions compressed has been performed. With the method of dual compressed sensing (CS) we derive, the spectral image of a colored object can be obtained with only a single point detector, and sub-sampling is achieved in both spatial and spectral domains. The performances of dual CS spectral imaging are analyzed, including the effects of dual modulation numbers and measurement noise on the imaging quality. Our scheme provides a stable, high-flux measurement approach of spectral imaging.

  13. Influence of Vacuum Cooling on Escherichia coli O157:H7 Infiltration in Fresh Leafy Greens via a Multiphoton-Imaging Approach

    PubMed Central

    Vonasek, Erica

    2015-01-01

    Microbial pathogen infiltration in fresh leafy greens is a significant food safety risk factor. In various postharvest operations, vacuum cooling is a critical process for maintaining the quality of fresh produce. The overall goal of this study was to evaluate the risk of vacuum cooling-induced infiltration of Escherichia coli O157:H7 into lettuce using multiphoton microscopy. Multiphoton imaging was chosen as the method to locate E. coli O157:H7 within an intact lettuce leaf due to its high spatial resolution, low background fluorescence, and near-infrared (NIR) excitation source compared to those of conventional confocal microscopy. The variables vacuum cooling, surface moisture, and leaf side were evaluated in a three-way factorial study with E. coli O157:H7 on lettuce. A total of 188 image stacks were collected. The images were analyzed for E. coli O157:H7 association with stomata and E. coli O157:H7 infiltration. The quantitative imaging data were statistically analyzed using analysis of variance (ANOVA). The results indicate that the low-moisture condition led to an increased risk of microbial association with stomata (P < 0.05). Additionally, the interaction between vacuum cooling levels and moisture levels led to an increased risk of infiltration (P < 0.05). This study also demonstrates the potential of multiphoton imaging for improving sensitivity and resolution of imaging-based measurements of microbial interactions with intact leaf structures, including infiltration. PMID:26475109

  14. In-vivo imaging of psoriatic lesions with polarization multispectral dermoscopy and multiphoton microscopy

    PubMed Central

    Kapsokalyvas, Dimitrios; Cicchi, Riccardo; Bruscino, Nicola; Alfieri, Domenico; Prignano, Francesca; Massi, Daniela; Lotti, Torello; Pavone, Francesco S.

    2014-01-01

    Psoriasis is a skin autoimmune disease characterized by hyperkeratosis, hyperproliferation of the epidermis and dilatation of dermal papillary blood vessels. Healthy skin (5 volunteers) and psoriatic lesions (3 patients) were visualized in vivo, with high contrast and resolution, with a Polarization Multispectral Dermoscope and a Multiphoton Microscope. Psoriatic features were identified and quantified. The effective diameter of the superficial blood vessels was measured at 35.2 ± 7.2 μm and the elongated dermal papillae had an effective diameter of 64.2 ± 22.6 μm. The methodologies developed could be employed for quantitative diagnostic purposes and furthermore serve as a monitoring method of the effect of personalized treatments. PMID:25071974

  15. Chiral asymmetry in the multiphoton ionization of methyloxirane using femtosecond electron-ion coincidence imaging.

    PubMed

    Rafiee Fanood, Mohammad M; Powis, Ivan; Janssen, Maurice H M

    2014-12-11

    Multiphoton photoelectron circular dichroism (MP-PECD) has been observed as an asymmetry in the angular distribution of photoelectrons emitted in the ionization of pure enantiomers of the small chiral molecule methyloxirane using a femtosecond laser operated at 420 nm. Energetically, this requires the uptake of four photons. By switching the laser between left- and right-circular polarization, and observing the differences in the full three-dimensional electron momentum distribution recorded in an electron-ion coincidence technique, the chiral (odd) terms in the angular distribution expression can be isolated. Electron events can additionally be filtered by coincident ion mass, providing mass-tagged electron distributions and quantitative measures of the MP-PECD asymmetry that help characterize the different ionization channels. For the production of ground state parent cation, the magnitude of the mean chiral asymmetry is measured to be 4.7%, with a peak magnitude exceeding 10% PMID:25402546

  16. In-vivo imaging of psoriatic lesions with polarization multispectral dermoscopy and multiphoton microscopy.

    PubMed

    Kapsokalyvas, Dimitrios; Cicchi, Riccardo; Bruscino, Nicola; Alfieri, Domenico; Prignano, Francesca; Massi, Daniela; Lotti, Torello; Pavone, Francesco S

    2014-07-01

    Psoriasis is a skin autoimmune disease characterized by hyperkeratosis, hyperproliferation of the epidermis and dilatation of dermal papillary blood vessels. Healthy skin (5 volunteers) and psoriatic lesions (3 patients) were visualized in vivo, with high contrast and resolution, with a Polarization Multispectral Dermoscope and a Multiphoton Microscope. Psoriatic features were identified and quantified. The effective diameter of the superficial blood vessels was measured at 35.2 ± 7.2 μm and the elongated dermal papillae had an effective diameter of 64.2 ± 22.6 μm. The methodologies developed could be employed for quantitative diagnostic purposes and furthermore serve as a monitoring method of the effect of personalized treatments. PMID:25071974

  17. Multiphoton time-domain fluorescence lifetime imaging microscopy: practical application to protein–protein interactions using global analysis

    PubMed Central

    Barber, P.R.; Ameer-Beg, S.M.; Gilbey, J.; Carlin, L.M.; Keppler, M.; Ng, T.C.; Vojnovic, B.

    2008-01-01

    Förster resonance energy transfer (FRET) detected via fluorescence lifetime imaging microscopy (FLIM) and global analysis provide a way in which protein–protein interactions may be spatially localized and quantified within biological cells. The FRET efficiency and proportion of interacting molecules have been determined using bi-exponential fitting to time-domain FLIM data from a multiphoton time-correlated single-photon counting microscope system. The analysis has been made more robust to noise and significantly faster using global fitting, allowing higher spatial resolutions and/or lower acquisition times. Data have been simulated, as well as acquired from cell experiments, and the accuracy of a modified Levenberg–Marquardt fitting technique has been explored. Multi-image global analysis has been used to follow the epidermal growth factor-induced activation of Cdc42 in a short-image-interval time-lapse FLIM/FRET experiment. Our implementation offers practical analysis and time-resolved-image manipulation, which have been targeted towards providing fast execution, robustness to low photon counts, quantitative results and amenability to automation and batch processing.

  18. HYMOSS signal processing for pushbroom spectral imaging

    NASA Technical Reports Server (NTRS)

    Ludwig, David E.

    1991-01-01

    The objective of the Pushbroom Spectral Imaging Program was to develop on-focal plane electronics which compensate for detector array non-uniformities. The approach taken was to implement a simple two point calibration algorithm on focal plane which allows for offset and linear gain correction. The key on focal plane features which made this technique feasible was the use of a high quality transimpedance amplifier (TIA) and an analog-to-digital converter for each detector channel. Gain compensation is accomplished by varying the feedback capacitance of the integrate and dump TIA. Offset correction is performed by storing offsets in a special on focal plane offset register and digitally subtracting the offsets from the readout data during the multiplexing operation. A custom integrated circuit was designed, fabricated, and tested on this program which proved that nonuniformity compensated, analog-to-digital converting circuits may be used to read out infrared detectors. Irvine Sensors Corporation (ISC) successfully demonstrated the following innovative on-focal-plane functions that allow for correction of detector non-uniformities. Most of the circuit functions demonstrated on this program are finding their way onto future IC's because of their impact on reduced downstream processing, increased focal plane performance, simplified focal plane control, reduced number of dewar connections, as well as the noise immunity of a digital interface dewar. The potential commercial applications for this integrated circuit are primarily in imaging systems. These imaging systems may be used for: security monitoring systems, manufacturing process monitoring, robotics, and for spectral imaging when used in analytical instrumentation.

  19. HYMOSS signal processing for pushbroom spectral imaging

    NASA Astrophysics Data System (ADS)

    Ludwig, David E.

    1991-06-01

    The objective of the Pushbroom Spectral Imaging Program was to develop on-focal plane electronics which compensate for detector array non-uniformities. The approach taken was to implement a simple two point calibration algorithm on focal plane which allows for offset and linear gain correction. The key on focal plane features which made this technique feasible was the use of a high quality transimpedance amplifier (TIA) and an analog-to-digital converter for each detector channel. Gain compensation is accomplished by varying the feedback capacitance of the integrate and dump TIA. Offset correction is performed by storing offsets in a special on focal plane offset register and digitally subtracting the offsets from the readout data during the multiplexing operation. A custom integrated circuit was designed, fabricated, and tested on this program which proved that nonuniformity compensated, analog-to-digital converting circuits may be used to read out infrared detectors. Irvine Sensors Corporation (ISC) successfully demonstrated the following innovative on-focal-plane functions that allow for correction of detector non-uniformities. Most of the circuit functions demonstrated on this program are finding their way onto future IC's because of their impact on reduced downstream processing, increased focal plane performance, simplified focal plane control, reduced number of dewar connections, as well as the noise immunity of a digital interface dewar. The potential commercial applications for this integrated circuit are primarily in imaging systems. These imaging systems may be used for: security monitoring systems, manufacturing process monitoring, robotics, and for spectral imaging when used in analytical instrumentation.

  20. Multiphoton microspectroscopy of biological specimens

    NASA Astrophysics Data System (ADS)

    Lin, Bai-Ling; Kao, Fu-Jen; Cheng, Ping C.; Sun, Chi-Kuang; Chen, RangWu; Wang, YiMin; Chen, JianCheng; Wang, Yung-Shun; Liu, Tzu-Ming; Huang, Mao-Kuo

    2000-07-01

    The non-linear nature of multi-photon fluorescence excitation restricts the fluorescing volume to the vicinity of the focal point. As a result, the technology has the capacity for micro- spectroscopy of biological specimen at high spatial resolution. Chloroplasts in mesophyll protoplast of Arabidopsis thaliana and maize stem sections were used to demonstrate the feasibility of multi-photon fluorescence micro-spectroscopy at subcellular compartments. Time-lapse spectral recording provides a means for studying the response of cell organelles to high intensity illumination.

  1. Multiphoton microscopy in neuroscience

    NASA Astrophysics Data System (ADS)

    Denk, Winfried

    2002-06-01

    The study of the nervous system requires to an exceptional extent observation of and experimentation on intact tissue. There, in particular, high-resolution optical microscopy benefits from the inherent advantages of multi-photon fluorescence excitation. Several cases will be presented from a number of different tissues and organisms, where multi-photon excited laser scanning fluorescence microscopy has been an essential experimental tool. Those examples include the discovery of biochemical coincidence detection in synaptic spines and the clarification of the underlying mechanism; the observation of sensory evoked dendritic signaling in intact animals and the observation of light induced calcium signals in the intact retina. Recently a fiber coupled two-photon microscopy has been developed that allows the imaging in moving animal.

  2. Assessment of liver steatosis and fibrosis in rats using integrated coherent anti-Stokes Raman scattering and multiphoton imaging technique

    NASA Astrophysics Data System (ADS)

    Lin, Jian; Lu, Fake; Zheng, Wei; Xu, Shuoyu; Tai, Dean; Yu, Hanry; Huang, Zhiwei

    2011-11-01

    We report the implementation of a unique integrated coherent anti-Stokes Raman scattering (CARS), second-harmonic generation (SHG), and two-photon excitation fluorescence (TPEF) microscopy imaging technique developed for label-free monitoring of the progression of liver steatosis and fibrosis generated in a bile duct ligation (BDL) rat model. Among the 21 adult rats used in this study, 18 rats were performed with BDL surgery and sacrificed each week from weeks 1 to 6 (n = 3 per week), respectively; whereas 3 rats as control were sacrificed at week 0. Colocalized imaging of the aggregated hepatic fats, collagen fibrils, and hepatocyte morphologies in liver tissue is realized by using the integrated CARS, SHG, and TPEF technique. The results show that there are significant accumulations of hepatic lipid droplets and collagen fibrils associated with severe hepatocyte necrosis in BDL rat liver as compared to a normal liver tissue. The volume of normal hepatocytes keeps decreasing and the fiber collagen content in BDL rat liver follows a growing trend until week 6; whereas the hepatic fat content reaches a maximum in week 4 and then appears to stop growing in week 6, indicating that liver steatosis and fibrosis induced in a BDL rat liver model may develop at different rates. This work demonstrates that the integrated CARS and multiphoton microscopy imaging technique has the potential to provide an effective means for early diagnosis and detection of liver steatosis and fibrosis without labeling.

  3. Detection limits with spectral differential imaging data

    NASA Astrophysics Data System (ADS)

    Rameau, J.; Chauvin, G.; Lagrange, A.-M.; Maire, A.-L.; Boccaletti, A.; Bonnefoy, M.

    2015-09-01

    Context. Direct imaging of exoplanets is polluted by speckle noise that severely limits the achievable contrast. Angular and spectral differential imaging have been proposed to make use of the temporal and chromatic properties of the speckles. Both modes, associated with extreme adaptive-optics and coronagraphy, are at the core of the new generation of planet imagers SPHERE and GPI. Aims: We aim to illustrate and characterize the impact of the SDI and SDI+ADI (ASDI) data reduction on the detection of giant planets. We also propose an unbiased method to derive the detection limits from SDI/ASDI data. Methods: Observations of AB Dor B and β Pictoris made with VLT/NaCo were used to simulate and quantify the effects of SDI and ASDI. The novel method is compared to the traditional injection of artificial point sources. Results: The SDI reduction process creates a typical radial positive-negative pattern of any point-source. Its characteristics and its self-subtraction depend on the separation, but also on the spectral properties of the object. This work demonstrates that the self-subtraction cannot be reduced to a simple geometric effect. As a consequence, the detection performances of SDI observations cannot be expressed as a contrast in magnitude with the central star without the knowledge of the spectral properties of detectable companions. In addition, the residual noise cannot be converted into contrast and physical characteristics (mass, temperature) by standard calibration of flux losses. The proposed method takes the SDI bias into account to derive detection limits without the cost of massively injecting artificial sources into the data. Finally, the sensitivity of ASDI observations can be measured only with a control parameter on the algorithms that controls the minimum rotation that is necessary to build the reference image. Based on observations collected at the European Organization for Astronomical Research in the Southern Hemisphere, Chile, ESO : 60.A

  4. Multiphoton microscopy, fluorescence lifetime imaging and optical spectroscopy for the diagnosis of neoplasia

    NASA Astrophysics Data System (ADS)

    Skala, Melissa Caroline

    2007-12-01

    Cancer morbidity and mortality is greatly reduced when the disease is diagnosed and treated early in its development. Tissue biopsies are the gold standard for cancer diagnosis, and an accurate diagnosis requires a biopsy from the malignant portion of an organ. Light, guided through a fiber optic probe, could be used to inspect regions of interest and provide real-time feedback to determine the optimal tissue site for biopsy. This approach could increase the diagnostic accuracy of current biopsy procedures. The studies in this thesis have characterized changes in tissue optical signals with carcinogenesis, increasing our understanding of the sensitivity of optical techniques for cancer detection. All in vivo studies were conducted on the dimethylbenz[alpha]anthracene treated hamster cheek pouch model of epithelial carcinogenesis. Multiphoton microscopy studies in the near infrared wavelength region quantified changes in tissue morphology and fluorescence with carcinogenesis in vivo. Statistically significant morphological changes with precancer included increased epithelial thickness, loss of stratification in the epithelium, and increased nuclear diameter. Fluorescence changes included a statistically significant decrease in the epithelial fluorescence intensity per voxel at 780 nm excitation, a decrease in the fluorescence lifetime of protein-bound nicotinamide adenine dinucleotide (NADH, an electron donor in oxidative phosphorylation), and an increase in the fluorescence lifetime of protein-bound flavin adenine dinucleotide (FAD, an electron acceptor in oxidative phosphorylation) with precancer. The redox ratio (fluorescence intensity of FAD/NADH, a measure of the cellular oxidation-reduction state) did not significantly change with precancer. Cell culture experiments (MCF10A cells) indicated that the decrease in protein-bound NADH with precancer could be due to increased levels of glycolysis. Point measurements of diffuse reflectance and fluorescence spectra in

  5. Quantifying local heterogeneity of in vivo transport dynamics using stochastic scanning multiphoton multifocal microscopy and segmented spatiotemporal image correlation spectroscopy

    NASA Astrophysics Data System (ADS)

    Kim, Hee Y.; Jureller, Justin E.; Kuznetsov, Andrey; Philipson, Louis H.; Scherer, Norbert F.

    2008-02-01

    Elucidating the mechanisms of insulin granule trafficking in pancreatic β-cells is a critical step in understanding Type II Diabetes and abnormal insulin secretion. In this paper, rapid-sampling stochastic scanning multiphoton multifocal microscopy (SS-MMM) was developed to capture fast insulin granule dynamics in vivo. Stochastic scanning of (a diffractive optic generated) 10×10 hexagonal array of foci with a galvanometer yields a uniformly sampled image with fewer spatio-temporal artifacts than obtained by conventional or multibeam raster scanning. In addition, segmented spatio-temporal image correlation spectroscopy (Segmented STICS) was developed to extract dynamics of insulin granules from the image sequences. Measurements we conducted on MIN6 cells, which exhibit an order of magnitude lower granule number density, allow comparison of particle tracking with Segmented-STICS. Segmentation of the images into 8×8 pixel segments (similar to a size of one granule) allows some amount of spatial averaging, which can reduce the computation time required to calculate the correlation function, yet retains information about the local spatial heterogeneity of transport. This allows the correlation analysis to quantify the dynamics within each of the segments producing a "map" of the localized properties of the cell. The results obtained from Segmented STICS are compared with dynamics determined from particle tracking analysis of the same images. The resulting range of diffusion coefficients of insulin granules are comparable to previously published values indicating that SS-MMM and segmented- STICS will be useful to address the imaging challenges presented by β-cells, particularly the extremely large number density of granules.

  6. Spectral imaging of neurosurgical target tissues through operation microscope

    NASA Astrophysics Data System (ADS)

    Antikainen, Jukka; von Und Zu Fraunberg, Mikael; Orava, Joni; Jaaskelainen, Juha E.; Hauta-Kasari, Markku

    2011-11-01

    It has been noticed that spectral information can be used for analyzing and separating different biological tissues. However, most of the studies for spectral image acquisitions are mainly done in vitro. Usually the main restrictions for in vivo measurements are the size or the weight of the spectral camera. If the camera weights too much, the surgery microscope cannot be stabilized. If the size of the camera is too big, it will disturb the surgeon or even risk the safety of the patient. The main goal of this study was to develop an independent spectral imaging device which can be used for collecting spectral information from the neurosurgeries without any previously described restrictions. Size of the imaging system is small enough not to disturb the surgeon during the surgery. The developed spectral imaging system is used for collecting a spectral database which can be used for the future imaging systems.

  7. Intravital multiphoton imaging of the selective uptake of water-dispersible quantum dots into sinusoidal liver cells.

    PubMed

    Liang, Xiaowen; Grice, Jeffrey E; Zhu, Yian; Liu, David; Sanchez, Washington Y; Li, Zhen; Crawford, Darrell H G; Le Couteur, David G; Cogger, Victoria C; Liu, Xin; Xu, Zhi Ping; Roberts, Michael S

    2015-04-01

    Although many studies reporting the organ-level biodistribution of nanoparticles (NPs) in animals, very few have addressed the fate of NPs in organs at the cellular level. The liver appears to be the main organ for accumulation of NPs after intravenous injection. In this study, for the first time, the in vivo spatiotemporal disposition of recently developed mercaptosuccinic acid (MSA)-capped cadmium telluride/cadmium sulfide (CdTe/CdS) quantum dots (QDs) is explored in rat liver using multiphoton microscopy (MPM) coupled with fluorescence lifetime imaging (FLIM), with subcellular resolution (∼1 μm). With high fluorescence efficiency and largely improved stability in the biological environment, these QDs show a distinct distribution pattern in the liver compared to organic dyes, rhodamine 123 and fluorescein. After intravenous injection, fluorescent molecules are taken up by hepatocytes and excreted into the bile, while negatively charged QDs are retained in the sinusoids and selectively taken up by sinusoidal cells (Kupffer cells and liver sinusoidal endothelial cells), but not by hepatocytes within 3 h. The results could help design NPs targeting the specific types of liver cells and choose the fluorescent markers for appropriate cellular imaging. PMID:25504510

  8. Examination of diagnostic features in multiphoton microscopy and optical coherence tomography images of ovarian tumorigenesis in a mouse model

    NASA Astrophysics Data System (ADS)

    Watson, Jennifer M.

    Ovarian cancer is a deadly disease owing to the non-specific symptoms and suspected rapid progression, leading to frequent late stage detection and poor prognosis. Medical imaging methods such as CT, MRI and ultrasound as well as serum testing for cancer markers have had extremely poor performance for early disease detection. Due to the poor performance of available screening methods, and the impracticality and ineffectiveness of taking tissue biopsies from the ovary, women at high risk for developing ovarian cancer are often advised to undergo prophylactic salpingo-oophorectomy. This surgery results in many side effects and is most often unnecessary since only a fraction of high risk women go on to develop ovarian cancer. Better understanding of the early development of ovarian cancer and characterization of morphological changes associated with early disease could lead to the development of an effective screening test for women at high risk. Optical imaging methods including optical coherence tomography (OCT) and multiphoton microscopy (MPM) are excellent tools for studying disease progression owing to the high resolution and depth sectioning capabilities. Further, these techniques are excellent for optical biopsy because they can image in situ non-destructively. In the studies described in this dissertation OCT and MPM are used to identify cellular and tissue morphological changes associated with early tumor development in a mouse model of ovarian cancer. This work is organized into three specific aims. The first aim is to use the images from the MPM phenomenon of second harmonic generation to quantitatively examine the morphological differences in collagen structure in normal mouse ovarian tissue and mouse ovarian tumors. The second aim is to examine the differences in endogenous two-photon excited fluorescence in normal mouse ovarian tissue and mouse ovarian tumors. The third and final aim is to identify changes in ovarian microstructure resulting from early

  9. Advances in multiphoton microscopy technology

    PubMed Central

    Hoover, Erich E.; Squier, Jeff A.

    2013-01-01

    Multiphoton microscopy has enabled unprecedented dynamic exploration in living organisms. A significant challenge in biological research is the dynamic imaging of features deep within living organisms, which permits the real-time analysis of cellular structure and function. To make progress in our understanding of biological machinery, optical microscopes must be capable of rapid, targeted access deep within samples at high resolution. In this Review, we discuss the basic architecture of a multiphoton microscope capable of such analysis and summarize the state-of-the-art technologies for the quantitative imaging of biological phenomena. PMID:24307915

  10. Spectral Camera based on Ghost Imaging via Sparsity Constraints

    PubMed Central

    Liu, Zhentao; Tan, Shiyu; Wu, Jianrong; Li, Enrong; Shen, Xia; Han, Shensheng

    2016-01-01

    The image information acquisition ability of a conventional camera is usually much lower than the Shannon Limit since it does not make use of the correlation between pixels of image data. Applying a random phase modulator to code the spectral images and combining with compressive sensing (CS) theory, a spectral camera based on true thermal light ghost imaging via sparsity constraints (GISC spectral camera) is proposed and demonstrated experimentally. GISC spectral camera can acquire the information at a rate significantly below the Nyquist rate, and the resolution of the cells in the three-dimensional (3D) spectral images data-cube can be achieved with a two-dimensional (2D) detector in a single exposure. For the first time, GISC spectral camera opens the way of approaching the Shannon Limit determined by Information Theory in optical imaging instruments. PMID:27180619

  11. Spectral Camera based on Ghost Imaging via Sparsity Constraints

    NASA Astrophysics Data System (ADS)

    Liu, Zhentao; Tan, Shiyu; Wu, Jianrong; Li, Enrong; Shen, Xia; Han, Shensheng

    2016-05-01

    The image information acquisition ability of a conventional camera is usually much lower than the Shannon Limit since it does not make use of the correlation between pixels of image data. Applying a random phase modulator to code the spectral images and combining with compressive sensing (CS) theory, a spectral camera based on true thermal light ghost imaging via sparsity constraints (GISC spectral camera) is proposed and demonstrated experimentally. GISC spectral camera can acquire the information at a rate significantly below the Nyquist rate, and the resolution of the cells in the three-dimensional (3D) spectral images data-cube can be achieved with a two-dimensional (2D) detector in a single exposure. For the first time, GISC spectral camera opens the way of approaching the Shannon Limit determined by Information Theory in optical imaging instruments.

  12. Spectral Camera based on Ghost Imaging via Sparsity Constraints.

    PubMed

    Liu, Zhentao; Tan, Shiyu; Wu, Jianrong; Li, Enrong; Shen, Xia; Han, Shensheng

    2016-01-01

    The image information acquisition ability of a conventional camera is usually much lower than the Shannon Limit since it does not make use of the correlation between pixels of image data. Applying a random phase modulator to code the spectral images and combining with compressive sensing (CS) theory, a spectral camera based on true thermal light ghost imaging via sparsity constraints (GISC spectral camera) is proposed and demonstrated experimentally. GISC spectral camera can acquire the information at a rate significantly below the Nyquist rate, and the resolution of the cells in the three-dimensional (3D) spectral images data-cube can be achieved with a two-dimensional (2D) detector in a single exposure. For the first time, GISC spectral camera opens the way of approaching the Shannon Limit determined by Information Theory in optical imaging instruments. PMID:27180619

  13. Mosaic-Detector-Based Fluorescence Spectral Imager

    NASA Technical Reports Server (NTRS)

    Son, Kyung-Ah; Moon, Jeong

    2007-01-01

    A battery-powered, pen-sized, portable instrument for measuring molecular fluorescence spectra of chemical and biological samples in the field has been proposed. Molecular fluorescence spectroscopy is among the techniques used most frequently in laboratories to analyze compositions of chemical and biological samples. Heretofore, it has been possible to measure fluorescence spectra of molecular species at relative concentrations as low as parts per billion (ppb), with a few nm spectral resolution. The proposed instrument would include a planar array (mosaic) of detectors, onto which a fluorescence spectrum would be spatially mapped. Unlike in the larger laboratory-type molecular fluorescence spectrometers, mapping of wavelengths to spatial positions would be accomplished without use of relatively bulky optical parts. The proposed instrument is expected to be sensitive enough to enable measurement of spectra of chemical species at relative concentrations <1 ppb, with spectral resolution that could be tailored by design to be comparable to a laboratory molecular fluorescence spectrometer. The proposed instrument (see figure) would include a button-cell battery and a laser diode, which would generate the monochromatic ultraviolet light needed to excite fluorescence in a sample. The sample would be held in a cell bounded by far-ultraviolet-transparent quartz or optical glass. The detector array would be, more specifically, a complementary metal oxide/ semiconductor or charge-coupled- device imaging photodetector array, the photodetectors of which would be tailored to respond to light in the wavelength range of the fluorescence spectrum to be measured. The light-input face of the photodetector array would be covered with a matching checkerboard array of multilayer thin film interference filters, such that each pixel in the array would be sensitive only to light in a spectral band narrow enough so as not to overlap significantly with the band of an adjacent pixel. The

  14. Detection of latent fingerprints by near-infrared spectral imaging

    NASA Astrophysics Data System (ADS)

    Huang, Wei; Dai, Yong

    2014-05-01

    Spectral imaging technology research is becoming more extensive in the field of examination of material evidence. Near-Infrared spectral imaging technology is an important part of the full spectrum of imaging technology. This paper finished the experiment contents of the Near-Infrared spectrum imaging method and image acquisition system Near-Infrared spectral imaging technology. The experiment of Near-Infrared spectral imaging method obtains the image set of the Near-Infrared spectrum, and formats a pseudo-color images to show the potential traces successfully by processing the set of spectral images; Near-Infrared spectral imaging technology explores the technology method of obtaining the image set of Near-Infrared spectrometer and image acquisition system, and extensive access to the Near-Infrared spectrum information of latent blood, stamp and smear fingerprints on common objects, and study the characteristics of the Near-Infrared spectrum. Near-Infrared spectroscopic imaging experiments explores a wide variety of Near-Infrared reflectance spectra of the object material curve and its Near-Infrared spectrum of imaging modalities, can not only gives a reference for choosing Near-Infrared wavelength to show the object surface potential traces of substances, but also gives important data for the Near-Infrared spectrum of imaging technology development.

  15. Piecewise spectrally band-pass for compressive coded aperture spectral imaging

    NASA Astrophysics Data System (ADS)

    Qian, Lu-Lu; Lü, Qun-Bo; Huang, Min; Xiang, Li-Bin

    2015-08-01

    Coded aperture snapshot spectral imaging (CASSI) has been discussed in recent years. It has the remarkable advantages of high optical throughput, snapshot imaging, etc. The entire spatial-spectral data-cube can be reconstructed with just a single two-dimensional (2D) compressive sensing measurement. On the other hand, for less spectrally sparse scenes, the insufficiency of sparse sampling and aliasing in spatial-spectral images reduce the accuracy of reconstructed three-dimensional (3D) spectral cube. To solve this problem, this paper extends the improved CASSI. A band-pass filter array is mounted on the coded mask, and then the first image plane is divided into some continuous spectral sub-band areas. The entire 3D spectral cube could be captured by the relative movement between the object and the instrument. The principle analysis and imaging simulation are presented. Compared with peak signal-to-noise ratio (PSNR) and the information entropy of the reconstructed images at different numbers of spectral sub-band areas, the reconstructed 3D spectral cube reveals an observable improvement in the reconstruction fidelity, with an increase in the number of the sub-bands and a simultaneous decrease in the number of spectral channels of each sub-band. Project supported by the National Natural Science Foundation for Distinguished Young Scholars of China (Grant No. 61225024) and the National High Technology Research and Development Program of China (Grant No. 2011AA7012022).

  16. Multiphoton cryo microscope with sample temperature control

    NASA Astrophysics Data System (ADS)

    Breunig, H. G.; Uchugonova, A.; König, K.

    2013-02-01

    We present a multiphoton microscope system which combines the advantages of multiphoton imaging with precise control of the sample temperature. The microscope provides online insight in temperature-induced changes and effects in plant tissue and animal cells with subcellular resolution during cooling and thawing processes. Image contrast is based on multiphoton fluorescence intensity or fluorescence lifetime in the range from liquid nitrogen temperature up to +600°C. In addition, micro spectra from the imaged regions can be recorded. We present measurement results from plant leaf samples as well as Chinese hamster ovary cells.

  17. A new method using multiphoton imaging and morphometric analysis for differentiating chromophobe renal cell carcinoma and oncocytoma kidney tumors

    NASA Astrophysics Data System (ADS)

    Wu, Binlin; Mukherjee, Sushmita; Jain, Manu

    2016-03-01

    Distinguishing chromophobe renal cell carcinoma (chRCC) from oncocytoma on hematoxylin and eosin images may be difficult and require time-consuming ancillary procedures. Multiphoton microscopy (MPM), an optical imaging modality, was used to rapidly generate sub-cellular histological resolution images from formalin-fixed unstained tissue sections from chRCC and oncocytoma.Tissues were excited using 780nm wavelength and emission signals (including second harmonic generation and autofluorescence) were collected in different channels between 390 nm and 650 nm. Granular structure in the cell cytoplasm was observed in both chRCC and oncocytoma. Quantitative morphometric analysis was conducted to distinguish chRCC and oncocytoma. To perform the analysis, cytoplasm and granules in tumor cells were segmented from the images. Their area and fluorescence intensity were found in different channels. Multiple features were measured to quantify the morphological and fluorescence properties. Linear support vector machine (SVM) was used for classification. Re-substitution validation, cross validation and receiver operating characteristic (ROC) curve were implemented to evaluate the efficacy of the SVM classifier. A wrapper feature algorithm was used to select the optimal features which provided the best predictive performance in separating the two tissue types (classes). Statistical measures such as sensitivity, specificity, accuracy and area under curve (AUC) of ROC were calculated to evaluate the efficacy of the classification. Over 80% accuracy was achieved as the predictive performance. This method, if validated on a larger and more diverse sample set, may serve as an automated rapid diagnostic tool to differentiate between chRCC and oncocytoma. An advantage of such automated methods are that they are free from investigator bias and variability.

  18. High spectral resolution image of Barnacle Bill

    NASA Technical Reports Server (NTRS)

    1997-01-01

    The rover Sojourner's first target for measurement by the Alpha-Proton-Xray Spectrometer (APXS) was the rock named Barnacle Bill, located close to the ramp down which the rover made its egress from the lander. The full spectral capability of the Imager for Mars Pathfinder (IMP), consisting of 13 wavelength filters, was used to characterize the rock's surface. The measured area is relatively dark, and is shown in blue. Nearby on the rock surface, soil material is trapped in pits (shown in red).

    Mars Pathfinder is the second in NASA's Discovery program of low-cost spacecraft with highly focused science goals. The Jet Propulsion Laboratory, Pasadena, CA, developed and manages the Mars Pathfinder mission for NASA's Office of Space Science, Washington, D.C. The Imager for Mars Pathfinder (IMP) was developed by the University of Arizona Lunar and Planetary Laboratory under contract to JPL. Peter Smith is the Principal Investigator. JPL is an operating division of the California Institute of Technology (Caltech).

  19. Non-rigid registration of multiphoton microscopy images using B-splines

    NASA Astrophysics Data System (ADS)

    Lorenz, Kevin S.; Salama, Paul; Dunn, Kenneth W.; Delp, Edward J.

    2011-03-01

    Optical microscopy poses many challenges for digital image analysis. One particular challenge includes correction of image artifacts due to respiratory motion from specimens imaged in vivo. We describe a non-rigid registration method using B-splines to correct these motion artifacts. Current attempts at non-rigid medical image registration have typically involved only a single pair of images. Extending these techniques to an entire series of images, possibly comprising hundreds of images, is presented in this paper. Our method involves creating a uniform grid of control points across each image in a stack. Each control point is manipulated by optimizing a cost function consisting of two parts: a term to determine image similarity, and a term to evaluate deformation grid smoothness. This process is repeated for all images in the stack. Analysis is evaluated using block motion estimation and other visualization techniques.

  20. Spectral edge: gradient-preserving spectral mapping for image fusion.

    PubMed

    Connah, David; Drew, Mark S; Finlayson, Graham D

    2015-12-01

    This paper describes a novel approach to image fusion for color display. Our goal is to generate an output image whose gradient matches that of the input as closely as possible. We achieve this using a constrained contrast mapping paradigm in the gradient domain, where the structure tensor of a high-dimensional gradient representation is mapped exactly to that of a low-dimensional gradient field which is then reintegrated to form an output. Constraints on output colors are provided by an initial RGB rendering. Initially, we motivate our solution with a simple "ansatz" (educated guess) for projecting higher-D contrast onto color gradients, which we expand to a more rigorous theorem to incorporate color constraints. The solution to these constrained optimizations is closed-form, allowing for simple and hence fast and efficient algorithms. The approach can map any N-D image data to any M-D output and can be used in a variety of applications using the same basic algorithm. In this paper, we focus on the problem of mapping N-D inputs to 3D color outputs. We present results in five applications: hyperspectral remote sensing, fusion of color and near-infrared or clear-filter images, multilighting imaging, dark flash, and color visualization of magnetic resonance imaging diffusion-tensor imaging. PMID:26831392

  1. High spectral resolution airborne short wave infrared hyperspectral imager

    NASA Astrophysics Data System (ADS)

    Wei, Liqing; Yuan, Liyin; Wang, Yueming; Zhuang, Xiaoqiong

    2016-05-01

    Short Wave InfraRed(SWIR) spectral imager is good at detecting difference between materials and penetrating fog and mist. High spectral resolution SWIR hyperspectral imager plays a key role in developing earth observing technology. Hyperspectral data cube can help band selections that is very important for multispectral imager design. Up to now, the spectral resolution of many SWIR hyperspectral imagers is about 10nm. A high sensitivity airborne SWIR hyperspectral imager with narrower spectral band will be presented. The system consists of TMA telescope, slit, spectrometer with planar blazed grating and high sensitivity MCT FPA. The spectral sampling interval is about 3nm. The IFOV is 0.5mrad. To eliminate the influence of the thermal background, a cold shield is designed in the dewar. The pixel number of spatial dimension is 640. Performance measurement in laboratory and image analysis for flight test will also be presented.

  2. Spatio-spectral image analysis using classical and neural algorithms

    SciTech Connect

    Roberts, S.; Gisler, G.R.; Theiler, J.

    1996-12-31

    Remote imaging at high spatial resolution has a number of environmental, industrial, and military applications. Analysis of high-resolution multi-spectral images usually involves either spectral analysis of single pixels in a multi- or hyper-spectral image or spatial analysis of multi-pixels in a panchromatic or monochromatic image. Although insufficient for some pattern recognition applications individually, the combination of spatial and spectral analytical techniques may allow the identification of more complex signatures that might not otherwise be manifested in the individual spatial or spectral domains. We report on some preliminary investigation of unsupervised classification methodologies (using both ``classical`` and ``neural`` algorithms) to identify potentially revealing features in these images. We apply dimension-reduction preprocessing to the images, duster, and compare the clusterings obtained by different algorithms. Our classification results are analyzed both visually and with a suite of objective, quantitative measures.

  3. Compressive spectral integral imaging using a microlens array

    NASA Astrophysics Data System (ADS)

    Feng, Weiyi; Rueda, Hoover; Fu, Chen; Qian, Chen; Arce, Gonzalo R.

    2016-05-01

    In this paper, a compressive spectral integral imaging system using a microlens array (MLA) is proposed. This system can sense the 4D spectro-volumetric information into a compressive 2D measurement image on the detector plane. In the reconstruction process, the 3D spatial information at different depths and the spectral responses of each spatial volume pixel can be obtained simultaneously. In the simulation, sensing of the 3D objects is carried out by optically recording elemental images (EIs) using a scanned pinhole camera. With the elemental images, a spectral data cube with different perspectives and depth information can be reconstructed using the TwIST algorithm in the multi-shot compressive spectral imaging framework. Then, the 3D spatial images with one dimensional spectral information at arbitrary depths are computed using the computational integral imaging method by inversely mapping the elemental images according to geometrical optics. The simulation results verify the feasibility of the proposed system. The 3D volume images and the spectral information of the volume pixels can be successfully reconstructed at the location of the 3D objects. The proposed system can capture both 3D volumetric images and spectral information in a video rate, which is valuable in biomedical imaging and chemical analysis.

  4. Hyperspectral retinal imaging with a spectrally tunable light source

    NASA Astrophysics Data System (ADS)

    Francis, Robert P.; Zuzak, Karel J.; Ufret-Vincenty, Rafael

    2011-03-01

    Hyperspectral retinal imaging can measure oxygenation and identify areas of ischemia in human patients, but the devices used by current researchers are inflexible in spatial and spectral resolution. We have developed a flexible research prototype consisting of a DLP®-based spectrally tunable light source coupled to a fundus camera to quickly explore the effects of spatial resolution, spectral resolution, and spectral range on hyperspectral imaging of the retina. The goal of this prototype is to (1) identify spectral and spatial regions of interest for early diagnosis of diseases such as glaucoma, age-related macular degeneration (AMD), and diabetic retinopathy (DR); and (2) define required specifications for commercial products. In this paper, we describe the challenges and advantages of using a spectrally tunable light source for hyperspectral retinal imaging, present clinical results of initial imaging sessions, and describe how this research can be leveraged into specifying a commercial product.

  5. A New Multichannel Spectral Imaging Laser Scanning Confocal Microscope

    PubMed Central

    Zhang, Yunhai; Hu, Bian; Dai, Yakang; Yang, Haomin; Huang, Wei; Xue, Xiaojun; Li, Fazhi; Zhang, Xin; Jiang, Chenyu; Gao, Fei; Chang, Jian

    2013-01-01

    We have developed a new multichannel spectral imaging laser scanning confocal microscope for effective detection of multiple fluorescent labeling in the research of biological tissues. In this paper, the design and key technologies of the system are introduced. Representative results on confocal imaging, 3-dimensional sectioning imaging, and spectral imaging are demonstrated. The results indicated that the system is applicable to multiple fluorescent labeling in biological experiments. PMID:23585775

  6. Spectral imaging of breast fibroadenoma using second-harmonic generation

    NASA Astrophysics Data System (ADS)

    Zheng, Liqin; Wang, Yuhua

    2014-09-01

    Fibroadenoma (FA), typically composed of stroma and epithelial cells, is a very common benign breast disease. Women with FA are associated with an increased risk of future breast cancer. The objective of this study was to demonstrate the potential of multiphoton laser scanning microscopy (MPLSM) for characterizing the morphology of collagen in the human breast fibroadenomas. In the study, high-contrast SHG images of human normal breast tissues and fibroadenoma tissues were obtained for comparison. The morphology of collagen was different between normal breast tissue and fibroadenoma. This study shows that MPLSM has the ability to distinguish fibroadenoma tissues from the normal breast tissues based on the noninvasive SHG imaging. With the advent of the clinical portability of miniature MPLSM, we believe that the technique has great potential to be used in vivo studies and for monitoring the treatment responses of fibroadenomas in clinical.

  7. Passive Microwave Spectral Imaging of Amospheric Structure

    NASA Technical Reports Server (NTRS)

    Staelin, David H.; Rosenkranz, Philip W.

    1998-01-01

    The primary objective of this research was to improve the scientific foundation necessary to full realization of the meteorological potential of the NOAA Advanced Microwave Sounding Unit (AMSU) recently first launched on the NOAA-15 satellite in May, 1998. These advances were made in four main areas: (1) improvements, based on aircraft observations, in the atmospheric transmittance expressions used for interpreting AMSU and similar data; (2) development of neural network retrieval methods for cloud top altitude estimates of approximately 1-km accuracy under cirrus shields--the altitude is that of the larger ice particles aloft, which is related to precipitation rate; (3) analysis of early AMSU flight data with respect to its precipitation sensitivity and fine-scale thermal structure; and (4) improvements to the 54-GHz and 118-GHz MTS aircraft imaging spectrometer now operating on the NASA ER-2 aircraft. More specifically, the oxygen transmittance expressions near 118 GHz were in better agreement with aircraft data when the temperature dependence exponent of the 118.75-GHz linewidth was increased from the MPM92 value (Liebe et al., 1992) of 0.8 to 0.97+/-0.03. In contrast, the observations 52.5-55.8 GHz were consistent with the MPM92 model. Neural networks trained on comparisons of 118-GHz spectral data and coincident stereoscopic video images of convective cells observed from 20-km altitude yielded agreement in their peak altitudes within as little as 1.36 km rms, much of which is stereoscopic error. Imagery using these methods produced useful characterizations for Cyclone Oliver in 1993 and other storms (Schwartz et al., 1996; Spina et al., 1998). Similar neural network techniques yielded simulated rms errors in relative humidity retrievals of 6-14 percent over ocean and 6-15 percent over land at pressure levels from 1013 to 131 mbar (Cabrera-Mercader and Staelin, 1995).

  8. Spectral Imaging of Galaxy Clusters with Planck

    NASA Astrophysics Data System (ADS)

    Bourdin, H.; Mazzotta, P.; Rasia, E.

    2015-12-01

    The Sunyaev-Zeldovich (SZ) effect is a promising tool for detecting the presence of hot gas out to the galaxy cluster peripheries. We developed a spectral imaging algorithm dedicated to the SZ observations of nearby galaxy clusters with Planck, with the aim of revealing gas density anisotropies related to the filamentary accretion of materials, or pressure discontinuities induced by the propagation of shock fronts. To optimize an unavoidable trade-off between angular resolution and precision of the SZ flux measurements, the algorithm performs a multi-scale analysis of the SZ maps as well as of other extended components, such as the cosmic microwave background (CMB) anisotropies and the Galactic thermal dust. The demixing of the SZ signal is tackled through kernel-weighted likelihood maximizations. The CMB anisotropies are further analyzed through a wavelet analysis, while the Galactic foregrounds and SZ maps are analyzed via a curvelet analysis that best preserves their anisotropic details. The algorithm performance has been tested against mock observations of galaxy clusters obtained by simulating the Planck High Frequency Instrument and by pointing at a few characteristic positions in the sky. These tests suggest that Planck should easily allow us to detect filaments in the cluster peripheries and detect large-scale shocks in colliding galaxy clusters that feature favorable geometry.

  9. In vivo Delivery of Fluoresceinated Dextrans to the Murine Growth Plate: Imaging of Three Vascular Routes by Multiphoton Microscopy

    PubMed Central

    Farnum, Cornelia; Lenox, Michelle; Zipfel, Warren; Horton, William; Williams, Rebecca

    2008-01-01

    Bone elongation by endochondral ossification occurs through the differentiation cascade of chondrocytes of cartilaginous growth plates. Molecules from the systemic vasculature reach the growth plate from three different directions: epiphyseal, metaphyseal, and via a ring vessel and plexus associated with the perichondrium. This study is an analysis of the real-time dynamics of entrance of fluoresceinated tracers of different molecular weights into the growth plate from the systemic vasculature, and tests the hypothesis that molecular weight is a key variable in the determination of both the directionality and the extent of tracer movement into the growth plate. Multiphoton microscopy was used for direct in vivo imaging of the murine proximal tibial growth plate in anesthetized 4-5-week-old transgenic mice with green fluorescent protein linked to the collagen II promoter. Mice were given an intracardiac injection of either fluorescein (332.3 Da), or fluoresceinated dextrans of 3, 10, 40, 70 kDa, singly or sequentially. For each tracer, directionality and rate of arrival, together with extent of movement within the growth plate, were imaged in real time. For small molecules (up to 10 kDa) vascular access from all three directions was observed and entrance was equally permissive from the metaphyseal and the epiphyseal sides. Within our detection limit (a few per cent of vascular concentration) 40 kDa and larger dextrans did not enter. These results have implications both for understanding systemic and paracrine regulation of growth plate chondrocytic differentiation, as well as variables associated with effective drug delivery to growth plate chondrocytes. PMID:16342207

  10. Results of ACTIM: an EDA study on spectral laser imaging

    NASA Astrophysics Data System (ADS)

    Hamoir, Dominique; Hespel, Laurent; Déliot, Philippe; Boucher, Yannick; Steinvall, Ove; Ahlberg, Jörgen; Larsson, Hakan; Letalick, Dietmar; Lutzmann, Peter; Repasi, Endre; Ritt, Gunnar

    2011-11-01

    The European Defence Agency (EDA) launched the Active Imaging (ACTIM) study to investigate the potential of active imaging, especially that of spectral laser imaging. The work included a literature survey, the identification of promising military applications, system analyses, a roadmap and recommendations. Passive multi- and hyper-spectral imaging allows discriminating between materials. But the measured radiance in the sensor is difficult to relate to spectral reflectance due to the dependence on e.g. solar angle, clouds, shadows... In turn, active spectral imaging offers a complete control of the illumination, thus eliminating these effects. In addition it allows observing details at long ranges, seeing through degraded atmospheric conditions, penetrating obscurants (foliage, camouflage...) or retrieving polarization information. When 3D, it is suited to producing numerical terrain models and to performing geometry-based identification. Hence fusing the knowledge of ladar and passive spectral imaging will result in new capabilities. We have identified three main application areas for active imaging, and for spectral active imaging in particular: (1) long range observation for identification, (2) mid-range mapping for reconnaissance, (3) shorter range perception for threat detection. We present the system analyses that have been performed for confirming the interests, limitations and requirements of spectral active imaging in these three prioritized applications.

  11. Evaluating collagen morphology and pathological lipid deposition using multiphoton image statistics

    NASA Astrophysics Data System (ADS)

    Mostaço-Guidolin, Leila B.; Ko, Alex C.-T.; Wang, Fei; Tian, Hong; Hewko, Mark; Shiomi, Masashi; Major, Arkady; Sowa, Michael G.

    2014-02-01

    In this study we present a novel image analysis methodology to quantify and to classify morphological details in tissue collagen fibril organization and lipid deposition. Co-localized collagen (second harmonic, SHG) and lipid (coherent Raman, CARS) images of atherosclerotic artery walls were acquired by a supercontinuum-powered multi-modal nonlinear microscope. Textural features based on the first-order statistics (FOS) and gray level co-occurrence matrix (GLCM) parameters were extracted from the SHG and CARS images. Multi-group classifications based on support vector machine of SHG and CARS images were subsequently performed to investigate the potential of texture analysis in providing quantitative descriptors of structural and compositional changes during disease progression. Using a rabbit model, different collagen remodeling and lipid accumulation patterns in disease tissues can be successfully tracked using these image statistics, thus providing a robust foundation for classification. When the variation of the CARS image features were tracked against the age of the rabbit, it was noticed that older animals (advanced plaques) present a more complex necrotic core containing high-lipid extracellular structures with various shapes and distribution. With combined FOS and GLCM texture statistics, we achieved reliable classification of SHG and CARS images acquired from atherosclerotic arteries with >90% accuracy, sensitivity and specificity. The proposed image analysis methodology can also be applied in a wide range of applications to evaluate conditions involving collagen re-modeling and prominent lipid accumulation.

  12. Spectrally resolved fluorescence lifetime imaging to investigate cell metabolism in malignant and nonmalignant oral mucosa cells

    NASA Astrophysics Data System (ADS)

    Rück, Angelika; Hauser, Carmen; Mosch, Simone; Kalinina, Sviatlana

    2014-09-01

    Fluorescence-guided diagnosis of tumor tissue is in many cases insufficient, because false positive results interfere with the outcome. Improvement through observation of cell metabolism might offer the solution, but needs a detailed understanding of the origin of autofluorescence. With respect to this, spectrally resolved multiphoton fluorescence lifetime imaging was investigated to analyze cell metabolism in metabolic phenotypes of malignant and nonmalignant oral mucosa cells. The time-resolved fluorescence characteristics of NADH were measured in cells of different origins. The fluorescence lifetime of bound and free NADH was calculated from biexponential fitting of the fluorescence intensity decay within different spectral regions. The mean lifetime was increased from nonmalignant oral mucosa cells to different squamous carcinoma cells, where the most aggressive cells showed the longest lifetime. In correlation with reports in the literature, the total amount of NADH seemed to be less for the carcinoma cells and the ratio of free/bound NADH was decreased from nonmalignant to squamous carcinoma cells. Moreover for squamous carcinoma cells a high concentration of bound NADH was found in cytoplasmic organelles (mainly mitochondria). This all together indicates that oxidative phosphorylation and a high redox potential play an important role in the energy metabolism of these cells.

  13. ACTIM: an EDA initiated study on spectral active imaging

    NASA Astrophysics Data System (ADS)

    Steinvall, O.; Renhorn, I.; Ahlberg, J.; Larsson, H.; Letalick, D.; Repasi, E.; Lutzmann, P.; Anstett, G.; Hamoir, D.; Hespel, L.; Boucher, Y.

    2010-10-01

    This paper will describe ongoing work from an EDA initiated study on Active Imaging with emphasis of using multi or broadband spectral lasers and receivers. Present laser based imaging and mapping systems are mostly based on a fixed frequency lasers. On the other hand great progress has recently occurred in passive multi- and hyperspectral imaging with applications ranging from environmental monitoring and geology to mapping, military surveillance, and reconnaissance. Data bases on spectral signatures allow the possibility to discriminate between different materials in the scene. Present multi- and hyperspectral sensors mainly operate in the visible and short wavelength region (0.4-2.5 μm) and rely on the solar radiation giving shortcoming due to shadows, clouds, illumination angles and lack of night operation. Active spectral imaging however will largely overcome these difficulties by a complete control of the illumination. Active illumination enables spectral night and low-light operation beside a robust way of obtaining polarization and high resolution 2D/3D information. Recent development of broadband lasers and advanced imaging 3D focal plane arrays has led to new opportunities for advanced spectral and polarization imaging with high range resolution. Fusing the knowledge of ladar and passive spectral imaging will result in new capabilities in the field of EO-sensing to be shown in the study. We will present an overview of technology, systems and applications for active spectral imaging and propose future activities in connection with some prioritized applications.

  14. Spectral homogenization techniques for the hyperspectral image projector

    NASA Astrophysics Data System (ADS)

    Hillberry, Logan E.; Rice, Joseph P.

    2015-05-01

    In an effort to improve technology for performance testing and calibration of multispectral and hyperspectral imagers, the National Institute of Standards and Technology (NIST) has been developing a Hyperspectral Image Projector (HIP) capable of projecting dynamic scenes than include distinct, programmable spectra in each of its 1024x768 spatial pixels. The HIP is comprised of a spectral engine, which is a light source capable generating the spectra in the scene, coupled to a spatial engine, capable of projecting the spectra into the correct locations of the scene. In the prototype HIP, the light exiting the Visible-Near-Infrared (VNIR) / Short-Wavelength Infrared (SWIR) spectral engine is spectrally dispersed and needs to be spectrally homogenized before it enters the spatial engine. In this paper we describe the results from a study of several different techniques for performing this spectral homogenization. These techniques include an integrating sphere, a liquid light guide, a randomized fiber bundle, and an engineered diffuser, in various combinations. The spectral uniformity of projected HIP scenes is measured and analyzed using the spectral angle mapper (SAM) algorithm over the VNIR spectral range. The SAM provides a way to analyze the spectral uniformity independently from the radiometric uniformity. The goal of the homogenizer is a spectrally uniform and bright projected image. An integrating sphere provides the most spectrally uniform image, but at a great loss of light compared with the other methods. The randomized fiber bundle generally outperforms the liquid light guide in both spectral homogenization and brightness. Using an engineered diffuser with the randomized fiber bundle increases the spectral uniformity by a factor of five, with a decrease in brightness by a factor of five, compared with the randomized fiber bundle alone. The combination of an engineered diffuser with a randomized fiber bundle provides comparable spectral uniformity to the

  15. SAR image change detection using watershed and spectral clustering

    NASA Astrophysics Data System (ADS)

    Niu, Ruican; Jiao, L. C.; Wang, Guiting; Feng, Jie

    2011-12-01

    A new method of change detection in SAR images based on spectral clustering is presented in this paper. Spectral clustering is employed to extract change information from a pair images acquired on the same geographical area at different time. Watershed transform is applied to initially segment the big image into non-overlapped local regions, leading to reduce the complexity. Experiments results and system analysis confirm the effectiveness of the proposed algorithm.

  16. Hyperspectral image classification by a variable interval spectral average and spectral curve matching combined algorithm

    NASA Astrophysics Data System (ADS)

    Senthil Kumar, A.; Keerthi, V.; Manjunath, A. S.; Werff, Harald van der; Meer, Freek van der

    2010-08-01

    Classification of hyperspectral images has been receiving considerable attention with many new applications reported from commercial and military sectors. Hyperspectral images are composed of a large number of spectral channels, and have the potential to deliver a great deal of information about a remotely sensed scene. However, in addition to high dimensionality, hyperspectral image classification is compounded with a coarse ground pixel size of the sensor for want of adequate sensor signal to noise ratio within a fine spectral passband. This makes multiple ground features jointly occupying a single pixel. Spectral mixture analysis typically begins with pixel classification with spectral matching techniques, followed by the use of spectral unmixing algorithms for estimating endmembers abundance values in the pixel. The spectral matching techniques are analogous to supervised pattern recognition approaches, and try to estimate some similarity between spectral signatures of the pixel and reference target. In this paper, we propose a spectral matching approach by combining two schemes—variable interval spectral average (VISA) method and spectral curve matching (SCM) method. The VISA method helps to detect transient spectral features at different scales of spectral windows, while the SCM method finds a match between these features of the pixel and one of library spectra by least square fitting. Here we also compare the performance of the combined algorithm with other spectral matching techniques using a simulated and the AVIRIS hyperspectral data sets. Our results indicate that the proposed combination technique exhibits a stronger performance over the other methods in the classification of both the pure and mixed class pixels simultaneously.

  17. Adaptive spectral imager for space-based sensing

    NASA Astrophysics Data System (ADS)

    Vujkovic-Cvijin, Pajo; Goldstein, Neil; Fox, Marsha J.; Higbee, Shawn D.; Becker, Latika S.; Ooi, Teng K.

    2006-05-01

    Optical sensors aboard space vehicles designated to perform seeker functions need to generate multispectral images in the mid-wave infrared (MWIR) and long-wave infrared (LWIR) spectral regions in order to investigate and classify man-made space objects, and to distinguish them relative to the interfering scene clutter. The spectral imager part of the sensor collects spectral signatures of the observed objects in order to extract information on surface emissivity and target temperature, both important parameters for object-discrimination algorithms. The Adaptive Spectral Imager described in this paper fulfills two functions simultaneously: one output produces instantaneous two-dimensional polychromatic imagery for object acquisition and tracking, while the other output produces multispectral images for object discrimination and classification. The spectral and temporal resolution of the data produced by the spectral imager are adjustable in real time, making it possible to achieve optimum tradeoff between different sensing functions to match dynamic monitoring requirements during a mission. The system has high optical collection efficiency, with output data rates limited only by the readout speed of the detector array. The instrument has no macro-scale moving parts, and can be built in a robust, small-volume and lightweight package, suitable for integration with space vehicles. The technology is also applicable to multispectral imaging applications in diverse areas such as surveillance, agriculture, process control, and biomedical imaging, and can be adapted for use in any spectral domain from the ultraviolet (UV) to the LWIR region.

  18. Spectral ladar: towards active 3D multispectral imaging

    NASA Astrophysics Data System (ADS)

    Powers, Michael A.; Davis, Christopher C.

    2010-04-01

    In this paper we present our Spectral LADAR concept, an augmented implementation of traditional LADAR. This sensor uses a polychromatic source to obtain range-resolved 3D spectral images which are used to identify objects based on combined spatial and spectral features, resolving positions in three dimensions and up to hundreds of meters in distance. We report on a proof-of-concept Spectral LADAR demonstrator that generates spectral point clouds from static scenes. The demonstrator transmits nanosecond supercontinuum pulses generated in a photonic crystal fiber. Currently we use a rapidly tuned receiver with a high-speed InGaAs APD for 25 spectral bands with the future expectation of implementing a linear APD array spectrograph. Each spectral band is independently range resolved with multiple return pulse recognition. This is a critical feature, enabling simultaneous spectral and spatial unmixing of partially obscured objects when not achievable using image fusion of monochromatic LADAR and passive spectral imagers. This enables higher identification confidence in highly cluttered environments such as forested or urban areas (e.g. vehicles behind camouflage or foliage). These environments present challenges for situational awareness and robotic perception which can benefit from the unique attributes of Spectral LADAR. Results from this demonstrator unit are presented for scenes typical of military operations and characterize the operation of the device. The results are discussed here in the context of autonomous vehicle navigation and target recognition.

  19. Semiconductor Laser Multi-Spectral Sensing and Imaging

    PubMed Central

    Le, Han Q.; Wang, Yang

    2010-01-01

    Multi-spectral laser imaging is a technique that can offer a combination of the laser capability of accurate spectral sensing with the desirable features of passive multispectral imaging. The technique can be used for detection, discrimination, and identification of objects by their spectral signature. This article describes and reviews the development and evaluation of semiconductor multi-spectral laser imaging systems. Although the method is certainly not specific to any laser technology, the use of semiconductor lasers is significant with respect to practicality and affordability. More relevantly, semiconductor lasers have their own characteristics; they offer excellent wavelength diversity but usually with modest power. Thus, system design and engineering issues are analyzed for approaches and trade-offs that can make the best use of semiconductor laser capabilities in multispectral imaging. A few systems were developed and the technique was tested and evaluated on a variety of natural and man-made objects. It was shown capable of high spectral resolution imaging which, unlike non-imaging point sensing, allows detecting and discriminating objects of interest even without a priori spectroscopic knowledge of the targets. Examples include material and chemical discrimination. It was also shown capable of dealing with the complexity of interpreting diffuse scattered spectral images and produced results that could otherwise be ambiguous with conventional imaging. Examples with glucose and spectral imaging of drug pills were discussed. Lastly, the technique was shown with conventional laser spectroscopy such as wavelength modulation spectroscopy to image a gas (CO). These results suggest the versatility and power of multi-spectral laser imaging, which can be practical with the use of semiconductor lasers. PMID:22315555

  20. Real-time histology in liver disease using multiphoton microscopy with fluorescence lifetime imaging

    PubMed Central

    Wang, Haolu; Liang, Xiaowen; Mohammed, Yousuf H.; Thomas, James A.; Bridle, Kim R.; Thorling, Camilla A.; Grice, Jeffrey E.; Xu, Zhi Ping; Liu, Xin; Crawford, Darrell H. G.; Roberts, Michael S.

    2015-01-01

    Conventional histology with light microscopy is essential in the diagnosis of most liver diseases. Recently, a concept of real-time histology with optical biopsy has been advocated. In this study, live mice livers (normal, with fibrosis, steatosis, hepatocellular carcinoma and ischemia-reperfusion injury) were imaged by MPM-FLIM for stain-free real-time histology. The acquired MPM-FLIM images were compared with conventional histological images. MPM-FLIM imaged subsurface cellular and subcellular histopathological hallmarks of live liver in mice models at high resolution. Additional information such as distribution of stellate cell associated autofluorescence and fluorescence lifetime changes was also gathered by MPM-FLIM simultaneously, which cannot be obtained from conventional histology. MPM-FLIM could simultaneously image and quantify the cellular morphology and microenvironment of live livers without conventional biopsy or fluorescent dyes. We anticipate that in the near future MPM-FLIM will be evaluated from bench to bedside, leading to real-time histology and dynamic monitoring of human liver diseases. PMID:25798303

  1. Multiplexed Spectral Imaging of 120 Different Fluorescent Labels

    PubMed Central

    Valm, Alex M.; Oldenbourg, Rudolf; Borisy, Gary G.

    2016-01-01

    The number of fluorescent labels that can unambiguously be distinguished in a single image when acquired through band pass filters is severely limited by the spectral overlap of available fluorophores. The recent development of spectral microscopy and the application of linear unmixing algorithms to spectrally recorded image data have allowed simultaneous imaging of fluorophores with highly overlapping spectra. However, the number of distinguishable fluorophores is still limited by the unavoidable decrease in signal to noise ratio when fluorescence signals are fractionated over multiple wavelength bins. Here we present a spectral image analysis algorithm to greatly expand the number of distinguishable objects labeled with binary combinations of fluorophores. Our algorithm utilizes a priori knowledge about labeled specimens and imposes a binary label constraint on the unmixing solution. We have applied our labeling and analysis strategy to identify microbes labeled by fluorescence in situ hybridization and here demonstrate the ability to distinguish 120 differently labeled microbes in a single image. PMID:27391327

  2. [Research on Spectral Polarization Imaging System Based on Static Modulation].

    PubMed

    Zhao, Hai-bo; Li, Huan; Lin, Xu-ling; Wang, Zheng

    2015-04-01

    The main disadvantages of traditional spectral polarization imaging system are: complex structure, with moving parts, low throughput. A novel method of spectral polarization imaging system is discussed, which is based on static polarization intensity modulation combined with Savart polariscope interference imaging. The imaging system can obtain real-time information of spectral and four Stokes polarization messages. Compared with the conventional methods, the advantages of the imaging system are compactness, low mass and no moving parts, no electrical control, no slit and big throughput. The system structure and the basic theory are introduced. The experimental system is established in the laboratory. The experimental system consists of reimaging optics, polarization intensity module, interference imaging module, and CCD data collecting and processing module. The spectral range is visible and near-infrared (480-950 nm). The white board and the plane toy are imaged by using the experimental system. The ability of obtaining spectral polarization imaging information is verified. The calibration system of static polarization modulation is set up. The statistical error of polarization degree detection is less than 5%. The validity and feasibility of the basic principle is proved by the experimental result. The spectral polarization data captured by the system can be applied to object identification, object classification and remote sensing detection. PMID:26197616

  3. USE OF MULTIPHOTON LASER SCANNING MICROSCOPY TO IMAGE BENZO[A]PYRENE AND METABOLITES IN FISH EGGS

    EPA Science Inventory

    Multiphoton laser scanning microscopy (MPLSM) is a promising tool to study the tissue distribution of environmental chemical contaminants during fish early life stages. One such chemical for which this is possible is benzo[a]pyrene (BaP), a polycyclic aromatic hydrocarbon that a...

  4. USE OF MULTIPHOTON LASER SCANNING MICROSCOPY TO IMAGE BENZO[A]PYRENE AND METABOLITES IN FISH EARLY LIFE STAGES

    EPA Science Inventory

    Multiphoton laser scanning micrsocopy holds promise as a tool to study the tissue distribution of environmental chemical contaminants during fish early life stage development. One such chemical for which this is possible is benzo[a]pyrene (BaP), a polyaromatic hydrocarbon that a...

  5. Infrared adaptive spectral imagers for direct detection of spectral signatures and hyperspectral imagery

    NASA Astrophysics Data System (ADS)

    Goldstein, Neil; Fox, Marsha; Adler-Golden, Steven; Gregor, Brian

    2013-03-01

    Field test results are presented for a prototype long-wave adaptive imager that provides both hyperspectral imagery and contrast imagery based on the direct application of hyperspectral detection algorithms in hardware. Programmable spatial light modulators are used to provide both spectral and spatial resolution using a single element detector. Programmable spectral and spatial detection filters can be used to superimpose any possible analog spectral detection filter on the image. In this work, we demonstrate three modes of operation, including hyperspectral imagery, and one and two-dimensional imagery using a generalized matched filter for detection of a specific target gas within the scene.

  6. An integrated coherent anti-Stokes Raman scattering and multiphoton imaging technique for liver disease diagnosis

    NASA Astrophysics Data System (ADS)

    Lin, Jian; Lu, Fake; Zheng, Wei; Yu, Hanry; Sheppard, Colin; Huang, Zhiwei

    2012-03-01

    Liver steatosis and fibrosis are two prevalence liver diseases and may eventually develop into hepatocellular carcinoma (HCC) Due to their prevalence and severity, much work has been done to develop efficient diagnostic methods and therapies. Nonlinear optical microscopy has high sensitivity and chemical specificity for major biochemical compounds, making it a powerful tool for tissue imaging without staining. In this study, three nonlinear microscopy imaging modalities are applied to the study of liver diseases in a bile duct ligation rat modal. CARS shows the distributions of fats or lipids quantitatively across the tissue; SHG visualizes the collagens; and TPEF reveals the morphology of hepatic cells. The results clearly show the development of liver steatosis and fibrosis with time, and the hepatic fat and collagen fibrils are quantified. This study demonstrates the ability of multimodal nonlinear optical microscopy for liver disease diagnosis, and may provide new insights into the understanding of the mechanisms of steatosis/fibrosis transformations at the cellular and molecular levels.

  7. Multiphoton fluorescence lifetime imaging of metabolic status in mesenchymal stem cell during adipogenic differentiation

    NASA Astrophysics Data System (ADS)

    Meleshina, A. V.; Dudenkova, V. V.; Shirmanova, M. V.; Bystrova, A. S.; Zagaynova, E. V.

    2016-03-01

    Non-invasive imaging of cell metabolism is a valuable approach to assess the efficacy of stem cell therapy and understand the tissue development. In this study we analyzed metabolic trajectory of the mesenchymal stem cells (MCSs) during differentiation into adipocytes by measuring fluorescence lifetimes of free and bound forms of the reduced nicotinamide adenine dinucleotide (NAD(P)H) and flavine adenine dinucleotide (FAD). Undifferentiated MSCs and MSCs on the 5, 12, 19, 26 days of differentiation were imaged on a Zeiss 710 microscope with fluorescence lifetime imaging (FLIM) system B&H (Germany). Fluorescence of NAD(P)H and FAD was excited at 750 nm and 900 nm, respectively, by a femtosecond Ti:sapphire laser and detected in a range 455-500 nm and 500-550 nm, correspondingly. We observed the changes in the NAD(P)H and FAD fluorescence lifetimes and their relative contributions in the differentiated adipocytes compare to undifferentiated MSCs. Increase of fluorescence lifetimes of the free and bound forms of NAD(P)H and the contribution of protein-bound NAD(P)H was registered, that can be associated with a metabolic switch from glycolysis to oxidative phosphorylation and/or synthesis of lipids in adipogenically differentiated MSCs. We also found that the contribution of protein-bound FAD decreased during differentiation. After carrying out appropriate biochemical measurements, the observed changes in cellular metabolism can potentially serve to monitor stem cell differentiation by FLIM.

  8. Photodissociation dynamics of nitromethane and methyl nitrite by infrared multiphoton dissociation imaging with quasiclassical trajectory calculations: Signatures of the roaming pathway

    NASA Astrophysics Data System (ADS)

    Dey, Arghya; Fernando, Ravin; Abeysekera, Chamara; Homayoon, Zahra; Bowman, Joel M.; Suits, Arthur G.

    2014-02-01

    We combine the techniques of infrared multiphoton dissociation (IRMPD) with state selective ion imaging to probe roaming dynamics in the unimolecular dissociation of nitromethane and methyl nitrite. Recent theoretical calculations suggest a "roaming-mediated isomerization" pathway of nitromethane to methyl nitrite prior to decomposition. State-resolved imaging of the NO product coupled with infrared multiphoton dissociation was carried out to examine this unimolecular decomposition near threshold. The IRMPD images for the NO product from nitromethane are consistent with the earlier IRMPD studies that first suggested the importance of an isomerization pathway. A significant Λ-doublet propensity is seen in nitromethane IRMPD but not methyl nitrite. The experimental observations are augmented by quasiclassical trajectory calculations for nitromethane and methyl nitrite near threshold for each dissociation pathway. The observation of distinct methoxy vibrational excitation for trajectories from nitromethane and methyl nitrite dissociation at the same total energy show that the nitromethane dissociation bears a nonstatistical signature of the roaming isomerization pathway, and this is possibly responsible for the nitromethane Λ-doublet propensity as well.

  9. Colored coded-apertures for spectral image unmixing

    NASA Astrophysics Data System (ADS)

    Vargas, Hector M.; Arguello Fuentes, Henry

    2015-10-01

    Hyperspectral remote sensing technology provides detailed spectral information from every pixel in an image. Due to the low spatial resolution of hyperspectral image sensors, and the presence of multiple materials in a scene, each pixel can contain more than one spectral signature. Therefore, endmember extraction is used to determine the pure spectral signature of the mixed materials and its corresponding abundance map in a remotely sensed hyperspectral scene. Advanced endmember extraction algorithms have been proposed to solve this linear problem called spectral unmixing. However, such techniques require the acquisition of the complete hyperspectral data cube to perform the unmixing procedure. Researchers show that using colored coded-apertures improve the quality of reconstruction in compressive spectral imaging (CSI) systems under compressive sensing theory (CS). This work aims at developing a compressive supervised spectral unmixing scheme to estimate the endmembers and the abundance map from compressive measurements. The compressive measurements are acquired by using colored coded-apertures in a compressive spectral imaging system. Then a numerical procedure estimates the sparse vector representation in a 3D dictionary by solving a constrained sparse optimization problem. The 3D dictionary is formed by a 2-D wavelet basis and a known endmembers spectral library, where the Wavelet basis is used to exploit the spatial information. The colored coded-apertures are designed such that the sensing matrix satisfies the restricted isometry property with high probability. Simulations show that the proposed scheme attains comparable results to the full data cube unmixing technique, but using fewer measurements.

  10. Spectral reflectance and digital image relations among five aquatic weeds

    Technology Transfer Automated Retrieval System (TEKTRAN)

    This study reports on the use of an artificial quartz halogen lighting source to facilitate the acquisition of spectral light reflectance measurements and digital imaging of invasive aquatic weeds. Spectral leaf or leaf/stem reflectance measurements were made on five aquatic weeds: Eurasian watermil...

  11. New spectral imaging techniques for blood oximetry in the retina

    NASA Astrophysics Data System (ADS)

    Alabboud, Ied; Muyo, Gonzalo; Gorman, Alistair; Mordant, David; McNaught, Andrew; Petres, Clement; Petillot, Yvan R.; Harvey, Andrew R.

    2007-07-01

    Hyperspectral imaging of the retina presents a unique opportunity for direct and quantitative mapping of retinal biochemistry - particularly of the vasculature where blood oximetry is enabled by the strong variation of absorption spectra with oxygenation. This is particularly pertinent both to research and to clinical investigation and diagnosis of retinal diseases such as diabetes, glaucoma and age-related macular degeneration. The optimal exploitation of hyperspectral imaging however, presents a set of challenging problems, including; the poorly characterised and controlled optical environment of structures within the retina to be imaged; the erratic motion of the eye ball; and the compounding effects of the optical sensitivity of the retina and the low numerical aperture of the eye. We have developed two spectral imaging techniques to address these issues. We describe first a system in which a liquid crystal tuneable filter is integrated into the illumination system of a conventional fundus camera to enable time-sequential, random access recording of narrow-band spectral images. Image processing techniques are described to eradicate the artefacts that may be introduced by time-sequential imaging. In addition we describe a unique snapshot spectral imaging technique dubbed IRIS that employs polarising interferometry and Wollaston prism beam splitters to simultaneously replicate and spectrally filter images of the retina into multiple spectral bands onto a single detector array. Results of early clinical trials acquired with these two techniques together with a physical model which enables oximetry map are reported.

  12. Retinex Preprocessing for Improved Multi-Spectral Image Classification

    NASA Technical Reports Server (NTRS)

    Thompson, B.; Rahman, Z.; Park, S.

    2000-01-01

    The goal of multi-image classification is to identify and label "similar regions" within a scene. The ability to correctly classify a remotely sensed multi-image of a scene is affected by the ability of the classification process to adequately compensate for the effects of atmospheric variations and sensor anomalies. Better classification may be obtained if the multi-image is preprocessed before classification, so as to reduce the adverse effects of image formation. In this paper, we discuss the overall impact on multi-spectral image classification when the retinex image enhancement algorithm is used to preprocess multi-spectral images. The retinex is a multi-purpose image enhancement algorithm that performs dynamic range compression, reduces the dependence on lighting conditions, and generally enhances apparent spatial resolution. The retinex has been successfully applied to the enhancement of many different types of grayscale and color images. We show in this paper that retinex preprocessing improves the spatial structure of multi-spectral images and thus provides better within-class variations than would otherwise be obtained without the preprocessing. For a series of multi-spectral images obtained with diffuse and direct lighting, we show that without retinex preprocessing the class spectral signatures vary substantially with the lighting conditions. Whereas multi-dimensional clustering without preprocessing produced one-class homogeneous regions, the classification on the preprocessed images produced multi-class non-homogeneous regions. This lack of homogeneity is explained by the interaction between different agronomic treatments applied to the regions: the preprocessed images are closer to ground truth. The principle advantage that the retinex offers is that for different lighting conditions classifications derived from the retinex preprocessed images look remarkably "similar", and thus more consistent, whereas classifications derived from the original

  13. Stochastic scanning multiphoton multifocal microscopy.

    PubMed

    Jureller, Justin E; Kim, Hee Y; Scherer, Norbert F

    2006-04-17

    Multiparticle tracking with scanning confocal and multiphoton fluorescence imaging is increasingly important for elucidating biological function, as in the transport of intracellular cargo-carrying vesicles. We demonstrate a simple rapid-sampling stochastic scanning multifocal multiphoton microscopy (SS-MMM) fluorescence imaging technique that enables multiparticle tracking without specialized hardware at rates 1,000 times greater than conventional single point raster scanning. Stochastic scanning of a diffractive optic generated 10x10 hexagonal array of foci with a white noise driven galvanometer yields a scan pattern that is random yet space-filling. SS-MMM creates a more uniformly sampled image with fewer spatio-temporal artifacts than obtained by conventional or multibeam raster scanning. SS-MMM is verified by simulation and experimentally demonstrated by tracking microsphere diffusion in solution. PMID:19516485

  14. High-resolution multi-photon imaging of morphological structures of caenorhabditis elegans

    PubMed Central

    Bixel, M. Gabriele; Fretham, Stephanie J.B.; Aschner, Michael

    2015-01-01

    In this protocol, we combine two-photon excitation fluorescence to visualize in caenorhabditis elegans (C. elegans) dopaminergic (DAergic) neurons and their processes with non-linear optical measurements to reconstruct the three-dimensional architecture of the pharyngeal region and the muscular system of the anterior and mid-body region. Femto second laser pulses excite second-harmonic generation (SHG) and third harmonic generation (THG) signals, which show detailed structural information regarding the organization of myofibrils that are arranged around the central pharynx region. The combination of two-photon excitation with SHG and THG imaging is a very powerful tool to study cell morphology, the microarchitecture and tissue arrangement in C. elegans. PMID:26309451

  15. Instrumentation considerations in spectral imaging for tissue demarcation: comparing three methods of spectral resolution

    NASA Astrophysics Data System (ADS)

    Gebhart, Steven C.; Stokes, David L.; Vo-Dinh, Tuan; Mahadevan-Jansen, Anita

    2005-03-01

    Multiple methodologies exist to implement spectral imaging for tissue demarcation and disease diagnosis. In this paper, benchtop acousto-optic tunable filter (AOTF), liquid-crystal tunable filter (LCTF) and Fourier interferometric spectral imaging systems were quantitatively compared in terms of imaging speed of soft tissue autofluorescence. Optical throughput, image signal-to-noise ratio (SNR), and collagen autofluorescence imaging in chicken breast were assessed. Within this comparison, the Fourier system possessed the largest optical throughput (~50%) relative to the tunable-filter imaging systems; however, its throughput advantage failed to correlate to improved image SNR over the LCTF system. Further, while the autofluorescence imaging capability of the Fourier system exceeded that of the LCTF system for comparable total image integration times, the LCTF is capable of producing equivalent autofluorescence SNR with superior SNR when interrogations at only a few wavelengths are required and the random access filter tuning of the LCTF can be exploited. Therefore, the simple, rugged design and random-access filter-tuning capability of LCTF-based spectral imaging makes it best-suited for clinical development of soft tissue autofluorescence imaging.

  16. Integrated filter and detector array for spectral imaging

    NASA Technical Reports Server (NTRS)

    Labaw, Clayton C. (Inventor)

    1992-01-01

    A spectral imaging system having an integrated filter and photodetector array is disclosed. The filter has narrow transmission bands which vary in frequency along the photodetector array. The frequency variation of the transmission bands is matched to, and aligned with, the frequency variation of a received spectral image. The filter is deposited directly on the photodetector array by a low temperature deposition process. By depositing the filter directly on the photodetector array, permanent alignment is achieved for all temperatures, spectral crosstalk is substantially eliminated, and a high signal to noise ratio is achieved.

  17. Learning Hierarchical Spectral-Spatial Features for Hyperspectral Image Classification.

    PubMed

    Zhou, Yicong; Wei, Yantao

    2016-07-01

    This paper proposes a spectral-spatial feature learning (SSFL) method to obtain robust features of hyperspectral images (HSIs). It combines the spectral feature learning and spatial feature learning in a hierarchical fashion. Stacking a set of SSFL units, a deep hierarchical model called the spectral-spatial networks (SSN) is further proposed for HSI classification. SSN can exploit both discriminative spectral and spatial information simultaneously. Specifically, SSN learns useful high-level features by alternating between spectral and spatial feature learning operations. Then, kernel-based extreme learning machine (KELM), a shallow neural network, is embedded in SSN to classify image pixels. Extensive experiments are performed on two benchmark HSI datasets to verify the effectiveness of SSN. Compared with state-of-the-art methods, SSN with a deep hierarchical architecture obtains higher classification accuracy in terms of the overall accuracy, average accuracy, and kappa ( κ ) coefficient of agreement, especially when the number of the training samples is small. PMID:26241988

  18. A series of flexible design adaptations to the Nikon E-C1 and E-C2 confocal microscope systems for UV, multiphoton and FLIM imaging.

    PubMed

    Botchway, Stanley W; Scherer, Kathrin M; Hook, Steve; Stubbs, Christopher D; Weston, Eleanor; Bisby, Roger H; Parker, Anthony W

    2015-04-01

    Multiphoton microscopy is widely employed in the life sciences using extrinsic fluorescence of low- and high-molecular weight labels with excitation and emission spectra in the visible and near infrared regions. For imaging of intrinsic and extrinsic fluorophores with excitation spectra in the ultraviolet region, multiphoton excitation with one- or two-colour lasers avoids the need for ultraviolet-transmitting excitation optics and has advantages in terms of optical penetration in the sample and reduced phototoxicity. Excitation and detection of ultraviolet emission around 300 nm and below in a typical inverted confocal microscope is more difficult and requires the use of expensive quartz optics including the objective. In this technical note we describe the adaptation of a commercial confocal microscope (Nikon, Japan E-C1 or E-C2) for versatile use with Ti-sapphire and OPO laser sources and the addition of a second detection channel that enables detection of ultraviolet fluorescence and increases detection sensitivity in a typical fluorescence lifetime imaging microscopy experiment. Results from some experiments with this setup illustrate the resulting capabilities. PMID:25664385

  19. Microscopic spectral imaging using mid-infrared semiconductor lasers

    NASA Astrophysics Data System (ADS)

    Guo, Bujin-.; Wang, Yi; Peng, Chuan; Luo, Guipeng; Le, Han Q.

    2003-07-01

    Infrared micro-spectroscopy is a useful tool for basic research and biomedical applications. Conventional microspectroscopic imaging apparatuses use thermal sources for sample illumination, which have low brightness, low optical spectral intensity, and high noise. This work evaluates the system engineering advantages of using mid-infrared semiconductor lasers that offer orders-of magnitude higher brightness, spectral intensity, and lower noise. A laser-based microscopic spectral imaging system with focal plane array detectors demonstrated a high signal-to-noise ratio (>20 dB) at video frame rate for a large illuminated area. Microscopic spectral imaging with fixed-wavelength and tunable lasers of 4.6, 6, and 9.3-μm wavelength was applied to a number of representative samples that consist of biological tissues (plant and animal) and solid material (a stack of laminated polymers). Transmission spectral images with ~30-dB dynamic range were obtained with clear evidence of spectral features for different samples. The potential of more advanced systems with a wide coverage of spectral bands is discussed.

  20. Elucidation of the mechanisms of optical clearing in collagen tissue with multiphoton imaging

    NASA Astrophysics Data System (ADS)

    Hovhannisyan, Vladimir; Hu, Po-Sheng; Chen, Shean-Jen; Kim, Chang-Seok; Dong, Chen-Yuan

    2013-04-01

    Optical clearing (OC) is a promising method to overcome limitations in biomedical depth-resolved optical studies. Mechanisms of OC in purified bovine Achilles tendon, chicken skin, and chicken tendon were studied using time-lapsed, three-dimensional second harmonic generation (SHG) and two-photon fluorescence microscopic imaging. Quantified nonlinear optical measurements allowed temporal separation of two processes in collagen OC with glycerol. The first one is a fast process of tissue dehydration accompanied with collagen shrinkage and the second relatively slow process is glycerol penetration into the interfibrillar space of collagen alongside with CF swelling. The use of 50% glycerol induced less-expressed OC via partial substitution of water molecules with glycerol molecules. We also found that phosphate-buffered saline- and glycerol-treatments were reversible, and fiber morphology and SHG signal intensity were recovered after the removal of immersion agents. It was shown that tissue OC was a dynamic process and elucidation of its physical mechanisms may help choose optimal diagnostic, treatment, and modification regimes for collagen-based as well as other types of biomaterials.

  1. Dynamic multiphoton imaging of reversible and irreversible thermal changes in collagen tissues

    NASA Astrophysics Data System (ADS)

    Hovhannisyan, Vladimir A.; Su, Ping-Jung; Dong, Chen-Yuan

    2011-07-01

    Collagen is the major component of skin, tendon, cartilage, cornea, and, as a main structural protein it is the key determinant of thermo-mechanical properties of collagen-rich tissues in mammals. Thermal damage of chicken dermis and tendon, bovine leg tendon, and other collagen contained tissues were investigated with the use of second harmonic generation (SHG) and two-photon excited auto-fluorescence microscopy and spectroscopy. Samples were heating in a temperature-controlled water bath in the temperature range 18-90° C. SHG time-lapse imaging and analysis of intensity decay showed that the collagen thermal destruction depended on both temperature and heating time, and can be modeled by the Arrhenius equation. Temporal decay of SHG signal from the chicken dermis was single exponential during isothermal treatment at temperatures above 60º C that allowed to determine activation energy and frequency factor of skin collagen denaturation. Furthermore, two-exponential decay and partially reversible change in SHG intensity were registered during the tendon thermal treatment. A simple laser system and procedure is proposed for a real-time monitoring of collagen fiber thermal modification within a microscopic volume of 1 nl.

  2. Elucidation of the mechanisms of optical clearing in collagen tissue with multiphoton imaging.

    PubMed

    Hovhannisyan, Vladimir; Hu, Po-Sheng; Chen, Shean-Jen; Kim, Chang-Seok; Dong, Chen-Yuan

    2013-04-01

    Optical clearing (OC) is a promising method to overcome limitations in biomedical depth-resolved optical studies. Mechanisms of OC in purified bovine Achilles tendon, chicken skin, and chicken tendon were studied using time-lapsed, three-dimensional second harmonic generation (SHG) and two-photon fluorescence microscopic imaging. Quantified nonlinear optical measurements allowed temporal separation of two processes in collagen OC with glycerol. The first one is a fast process of tissue dehydration accompanied with collagen shrinkage and the second relatively slow process is glycerol penetration into the interfibrillar space of collagen alongside with CF swelling. The use of 50% glycerol induced less-expressed OC via partial substitution of water molecules with glycerol molecules. We also found that phosphate-buffered saline- and glycerol-treatments were reversible, and fiber morphology and SHG signal intensity were recovered after the removal of immersion agents. It was shown that tissue OC was a dynamic process and elucidation of its physical mechanisms may help choose optimal diagnostic, treatment, and modification regimes for collagen-based as well as other types of biomaterials. PMID:23552636

  3. Hyperspectral stimulated Raman scattering and multiphoton imaging for digital pathology of colonic disease

    NASA Astrophysics Data System (ADS)

    Wang, Zi; Zheng, Wei; Lin, Jian; Huang, Zhiwei

    2016-03-01

    Histopathology examinations of H&E stained biopsied tissues is the golden standard for colonic diseases (e.g., polyps, adenoma, and adenocarcinoma) diagnosis. However, staining effect of sample and doctor's expertise degree may greatly influence the diagnosis results. The information provided by the H&E stained sample is also limited to the morphological and PH information and no quantative information is available. In this paper, we report the development of a unique multimodal nonlinear optical microscopy (i.e., hyperspectral stimulated Raman scattering (hsSRS), second-harmonic generation (SHG), third-harmonic generation (THG), two-photon excitation fluorescence (TPEF)) platform for the diagnosis and characterization of colonic diseases. HsSRS in both fingerprint (800-1800 cm-1) and high-wavenumber (2800-3600 cm-1) regions allows us to discriminate different constituents with tiny difference in the Raman spectra. The increase of proteins and reduction of lipids could be observed with the progress of colonic cancer. SHG shows the distribution of collagen, which is found to aggregate for adenocarcinoma. TPEF provides the cell morphological and can reflect the damage inside glands caused by the diseases. THG shows the increase of optical heterogeneity related to cancer process. This work shows that the integrated hsSRS and TPEF/SHG/THG imaging technique can be an effective method for digital pathology of colonic diseases at the molecular and sub-cellular levels.

  4. Spectral image reconstruction by a tunable LED illumination

    NASA Astrophysics Data System (ADS)

    Lin, Meng-Chieh; Tsai, Chen-Wei; Tien, Chung-Hao

    2013-09-01

    Spectral reflectance estimation of an object via low-dimensional snapshot requires both image acquisition and a post numerical estimation analysis. In this study, we set up a system incorporating a homemade cluster of LEDs with spectral modulation for scene illumination, and a multi-channel CCD to acquire multichannel images by means of fully digital process. Principal component analysis (PCA) and pseudo inverse transformation were used to reconstruct the spectral reflectance in a constrained training set, such as Munsell and Macbeth Color Checker. The average reflectance spectral RMS error from 34 patches of a standard color checker were 0.234. The purpose is to investigate the use of system in conjunction with the imaging analysis for industry or medical inspection in a fast and acceptable accuracy, where the approach was preliminary validated.

  5. Methods for spectral image analysis by exploiting spatial simplicity

    DOEpatents

    Keenan, Michael R.

    2010-05-25

    Several full-spectrum imaging techniques have been introduced in recent years that promise to provide rapid and comprehensive chemical characterization of complex samples. One of the remaining obstacles to adopting these techniques for routine use is the difficulty of reducing the vast quantities of raw spectral data to meaningful chemical information. Multivariate factor analysis techniques, such as Principal Component Analysis and Alternating Least Squares-based Multivariate Curve Resolution, have proven effective for extracting the essential chemical information from high dimensional spectral image data sets into a limited number of components that describe the spectral characteristics and spatial distributions of the chemical species comprising the sample. There are many cases, however, in which those constraints are not effective and where alternative approaches may provide new analytical insights. For many cases of practical importance, imaged samples are "simple" in the sense that they consist of relatively discrete chemical phases. That is, at any given location, only one or a few of the chemical species comprising the entire sample have non-zero concentrations. The methods of spectral image analysis of the present invention exploit this simplicity in the spatial domain to make the resulting factor models more realistic. Therefore, more physically accurate and interpretable spectral and abundance components can be extracted from spectral images that have spatially simple structure.

  6. Methods for spectral image analysis by exploiting spatial simplicity

    DOEpatents

    Keenan, Michael R.

    2010-11-23

    Several full-spectrum imaging techniques have been introduced in recent years that promise to provide rapid and comprehensive chemical characterization of complex samples. One of the remaining obstacles to adopting these techniques for routine use is the difficulty of reducing the vast quantities of raw spectral data to meaningful chemical information. Multivariate factor analysis techniques, such as Principal Component Analysis and Alternating Least Squares-based Multivariate Curve Resolution, have proven effective for extracting the essential chemical information from high dimensional spectral image data sets into a limited number of components that describe the spectral characteristics and spatial distributions of the chemical species comprising the sample. There are many cases, however, in which those constraints are not effective and where alternative approaches may provide new analytical insights. For many cases of practical importance, imaged samples are "simple" in the sense that they consist of relatively discrete chemical phases. That is, at any given location, only one or a few of the chemical species comprising the entire sample have non-zero concentrations. The methods of spectral image analysis of the present invention exploit this simplicity in the spatial domain to make the resulting factor models more realistic. Therefore, more physically accurate and interpretable spectral and abundance components can be extracted from spectral images that have spatially simple structure.

  7. Spectral characteristics of two-photon autofluorescence and second harmonic generation from human skin in vivo

    NASA Astrophysics Data System (ADS)

    Breunig, Hans G.; König, Karsten

    2011-03-01

    We performed multiphoton imaging of human skin and recorded in combination the complete spectral content of the signals in vivo. The spectra represent the integration of multiphoton signals over the investigated regions of the epidermis and dermis. They are used to study depth-resolved in vivo emission characteristics of main endogenous skin fluorophores like keratin, NAD(P)H, collagen and elastin. The identification of the specific fluorophores is supported by analysis of additional in vivo fluorescence lifetime imaging. Furthermore, as a potential application of spectrally selective imaging the possibility to investigate the penetration of nanoparticles from sunscreen lotion into skin in vivo is discussed.

  8. Multiphoton microscopy of atheroslcerotic plaques

    NASA Astrophysics Data System (ADS)

    Lilledahl, Magnus B.; de Lange Davies, Catharina; Haugen, Olav A.; Svaasand, Lars O.

    2007-02-01

    Multiphoton microscopy is a techniques that fascilitates three dimensional imaging of intact, unstained tissue. Especially connective tissue has a relatively strong nonlinear optical response and can easily be imaged. Atherosclerosis is a disease where lipids accumulate in the vessel wall and there is a thickening of the intima by growth of a cap of connective tissue. The mechanical strength of this fibrous cap is of clinically importance. If the cap ruptures a thrombosis forms which can block a coronary vessel and therby causing myocardial infarction. Multiphoton microscopy can be used to image the fibrous cap and thereby determine the thickness of the cap and the structure of the connective fibres. This could possibly be developed into a diagnostic and clincal tool to monitor the vulnerability of a plaque and also to better understand the development of a plaque and effects of treatment. We have collected multiphoton microscopy images from atherosclerotic plaque in human aorta, both two photon excited fluorescens and second harmonic generated signal. The feasability of using this technique to determine the state of the plaque is explored.

  9. Advances in Spectral-Spatial Classification of Hyperspectral Images

    NASA Technical Reports Server (NTRS)

    Fauvel, Mathieu; Tarabalka, Yuliya; Benediktsson, Jon Atli; Chanussot, Jocelyn; Tilton, James C.

    2012-01-01

    Recent advances in spectral-spatial classification of hyperspectral images are presented in this paper. Several techniques are investigated for combining both spatial and spectral information. Spatial information is extracted at the object (set of pixels) level rather than at the conventional pixel level. Mathematical morphology is first used to derive the morphological profile of the image, which includes characteristics about the size, orientation and contrast of the spatial structures present in the image. Then the morphological neighborhood is defined and used to derive additional features for classification. Classification is performed with support vector machines using the available spectral information and the extracted spatial information. Spatial post-processing is next investigated to build more homogeneous and spatially consistent thematic maps. To that end, three presegmentation techniques are applied to define regions that are used to regularize the preliminary pixel-wise thematic map. Finally, a multiple classifier system is defined to produce relevant markers that are exploited to segment the hyperspectral image with the minimum spanning forest algorithm. Experimental results conducted on three real hyperspectral images with different spatial and spectral resolutions and corresponding to various contexts are presented. They highlight the importance of spectral-spatial strategies for the accurate classification of hyperspectral images and validate the proposed methods.

  10. Hyperspectral image-based methods for spectral diversity

    NASA Astrophysics Data System (ADS)

    Sotomayor, Alejandro; Medina, Ollantay; Chinea, J. D.; Manian, Vidya

    2015-05-01

    Hyperspectral images are an important tool to assess ecosystem biodiversity. To obtain more precise analysis of biodiversity indicators that agree with indicators obtained using field data, analysis of spectral diversity calculated from images have to be validated with field based diversity estimates. The plant species richness is one of the most important indicators of biodiversity. This indicator can be measured in hyperspectral images considering the Spectral Variation Hypothesis (SVH) which states that the spectral heterogeneity is related to spatial heterogeneity and thus to species richness. The goal of this research is to capture spectral heterogeneity from hyperspectral images for a terrestrial neo tropical forest site using Vector Quantization (VQ) method and then use the result for prediction of plant species richness. The results are compared with that of Hierarchical Agglomerative Clustering (HAC). The validation of the process index is done calculating the Pearson correlation coefficient between the Shannon entropy from actual field data and the Shannon entropy computed in the images. One of the advantages of developing more accurate analysis tools would be the extension of the analysis to larger zones. Multispectral image with a lower spatial resolution has been evaluated as a prospective tool for spectral diversity.

  11. Hyperspectral image segmentation using spatial-spectral graphs

    NASA Astrophysics Data System (ADS)

    Gillis, David B.; Bowles, Jeffrey H.

    2012-06-01

    Spectral graph theory has proven to be a useful tool in the analysis of high-dimensional data sets. Recall that, mathematically, a graph is a collection of objects (nodes) and connections between them (edges); a weighted graph additionally assigns numerical values (weights) to the edges. Graphs are represented by their adjacency whose elements are the weights between the nodes. Spectral graph theory uses the eigendecomposition of the adjacency matrix (or, more generally, the Laplacian of the graph) to derive information about the underlying graph. In this paper, we develop a spectral method based on the 'normalized cuts' algorithm to segment hyperspectral image data (HSI). In particular, we model an image as a weighted graph whose nodes are the image pixels, and edges defined as connecting spatial neighbors; the edge weights are given by a weighted combination of the spatial and spectral distances between nodes. We then use the Laplacian of the graph to recursively segment the image. The advantages of our approach are that, first, the graph structure naturally incorporates both the spatial and spectral information present in HSI; also, by using only spatial neighbors, the adjacency matrix is highly sparse; as a result, it is possible to apply our technique to much larger images than previous techniques. In the paper, we present the details of our algorithm, and include experimental results from a variety of hyperspectral images.

  12. A spatial-temporal-spectral blending model using satellite images

    NASA Astrophysics Data System (ADS)

    Zhang, L.; Fu, D.; Sun, X.; Chen, H.; She, X.

    2016-04-01

    Due to the budget and technical limitations, remote sensing sensor designs trade spatial resolution, swath width and spectral resolution. Consequently, no sensor can provide high spatial resolution, high temporal resolution and high spectral resolution simultaneously. However, the ability of Earth observation at fine resolution is urgently needed for global change science. One possible solution is to “blend” the reflectance from a variety of satellite data sources, including those providing high spatial resolution and less frequent coverage (e.g., Landsat Thematic Mapper, TM), daily global data (e.g., Moderate Resolution Imaging Spectroradiometer, MODIS), and high spectral resolution and infrequent revisit cycle (e.g., Hyperion). However, the previous algorithms for blending multi-source remotely sensed data have some shortcomings, especially with regard to hyperspectral information. This study has developed a SPAtial-Temporal-Spectral blending model (SPATS) that can simulate surface reflectance with high spatial-temporal-spectral resolution. SPATS is based on an existing spatial-temporal image blending model and a spatial-spectral image blending model. The performance of SPATS was tested with both simulated and observed satellite data, using Landsat TM, Hyperion and MODIS data, as well as heterogeneous landscapes as examples. The results show that the high spatial-temporal-spectral resolution reflectance data can be applied to investigations of global landscapes that are changing at different temporal scales.

  13. Extraction of topographic and spectral albedo information from multispectral images.

    USGS Publications Warehouse

    Eliason, P.T.; Soderblom, L.A.; Chavez, P.A., Jr.

    1981-01-01

    A technique has been developed to separate and extract spectral-reflectivity variations and topographic informaiton from multispectral images. The process is a completely closed system employing only the image data and can be applied to any digital multispectral data set. -from Authors

  14. Multi-spectral confocal microendoscope for in-vivo imaging

    NASA Astrophysics Data System (ADS)

    Rouse, Andrew Robert

    The concept of in-vivo multi-spectral confocal microscopy is introduced. A slit-scanning multi-spectral confocal microendoscope (MCME) was built to demonstrate the technique. The MCME employs a flexible fiber-optic catheter coupled to a custom built slit-scan confocal microscope fitted with a custom built imaging spectrometer. The catheter consists of a fiber-optic imaging bundle linked to a miniature objective and focus assembly. The design and performance of the miniature objective and focus assembly are discussed. The 3mm diameter catheter may be used on its own or routed though the instrument channel of a commercial endoscope. The confocal nature of the system provides optical sectioning with 3mum lateral resolution and 30mum axial resolution. The prism based multi-spectral detection assembly is typically configured to collect 30 spectral samples over the visible chromatic range. The spectral sampling rate varies from 4nm/pixel at 490nm to 8nm/pixel at 660nm and the minimum resolvable wavelength difference varies from 7nm to 18nm over the same spectral range. Each of these characteristics are primarily dictated by the dispersive power of the prism. The MCME is designed to examine cellular structures during optical biopsy and to exploit the diagnostic information contained within the spectral domain. The primary applications for the system include diagnosis of disease in the gastro-intestinal tract and female reproductive system. Recent data from the grayscale imaging mode are presented. Preliminary multi-spectral results from phantoms, cell cultures, and excised human tissue are presented to demonstrate the potential of in-vivo multi-spectral imaging.

  15. Multiphoton processes: conference proceedings

    SciTech Connect

    Lambropoulos, P.; Smith, S.J.

    1984-01-01

    The chapters of this volume represent the invited papers delivered at the conference. They are arranged according to thermatic proximity beginning with atoms and continuing with molecules and surfaces. Section headings include multiphoton processes in atoms, field fluctuations and collisions in multiphoton process, and multiphoton processes in molecules and surfaces. Abstracts of individual items from the conference were prepared separately for the data base. (GHT)

  16. Coded aperture design in mismatched compressive spectral imaging.

    PubMed

    Galvis, Laura; Arguello, Henry; Arce, Gonzalo R

    2015-11-20

    Compressive spectral imaging (CSI) senses a scene by using two-dimensional coded projections such that the number of measurements is far less than that used in spectral scanning-type instruments. An architecture that efficiently implements CSI is the coded aperture snapshot spectral imager (CASSI). A physical limitation of the CASSI is the system resolution, which is determined by the lowest resolution element used in the detector and the coded aperture. Although the final resolution of the system is usually given by the detector, in the CASSI, for instance, the use of a low resolution coded aperture implemented using a digital micromirror device (DMD), which induces the grouping of pixels in superpixels in the detector, is decisive to the final resolution. The mismatch occurs by the differences in the pitch size of the DMD mirrors and focal plane array (FPA) pixels. A traditional solution to this mismatch consists of grouping several pixels in square features, which subutilizes the DMD and the detector resolution and, therefore, reduces the spatial and spectral resolution of the reconstructed spectral images. This paper presents a model for CASSI which admits the mismatch and permits exploiting the maximum resolution of the coding element and the FPA sensor. A super-resolution algorithm and a synthetic coded aperture are developed in order to solve the mismatch. The mathematical models are verified using a real implementation of CASSI. The results of the experiments show a significant gain in spatial and spectral imaging quality over the traditional grouping pixel technique. PMID:26836551

  17. Colorimetric-spectral clustering: a tool for multispectral image compression

    NASA Astrophysics Data System (ADS)

    Ciprian, R.; Carbucicchio, M.

    2011-11-01

    In this work a new compression method for multispectral images has been proposed: the 'colorimetric-spectral clustering'. The basic idea arises from the well-known cluster analysis, a multivariate analysis which finds the natural links between objects grouping them into clusters. In the colorimetric-spectral clustering compression method, the objects are the spectral reflectance factors of the multispectral images that are grouped into clusters on the basis of their colour difference. In particular two spectra can belong to the same cluster only if their colour difference is lower than a threshold fixed before starting the compression procedure. The performance of the colorimetric-spectral clustering has been compared to the k-means cluster analysis, in which the Euclidean distance between spectra is considered, to the principal component analysis and to the LabPQR method. The colorimetric-spectral clustering is able to preserve both the spectral and the colorimetric information of a multispectral image, allowing this information to be reproduced for all pixels of the image.

  18. Multi-spectral imaging with mid-infrared semiconductor lasers

    NASA Astrophysics Data System (ADS)

    Wang, Yi; Wang, Yang; Le, Han Q.

    2006-01-01

    Multi-spectral laser imaging can be a useful technology for target discrimination, classification, and identification based on object spectral signatures. The mid-IR region (~3-14 μm) is particularly rich of molecular spectroscopic fingerprints, but the technology has been under utilized. Compact, potentially inexpensive semiconductor lasers may allow more cost-effective applications. This paper describes a development of semiconductor-laser-based multi-spectral imaging for both near-IR and mid-IR, and demonstrates the potential of this technology. The near-IR study employed 7 wavelengths from 0.635-1.55 μm, and used for system engineering evaluation as well as for studying the fundamental aspects of multi-spectral laser imaging. These include issues of wavelength-dependence scattering as a function of incident and receiving angle and the polarization effects. Stokes vector imaging and degree-of-linear-polarization were shown to reveal significant information to characterize the targets. The mid-IR study employed 4 wavelengths from 3.3-9.6 μm, and was applied to diverse targets that consist of natural and man-made materials and household objects. It was shown capable to resolve and distinguish small spectral differences among various targets, thanks to the laser radiometric and spectral accuracy. Colorless objects in the visible were shown with "colorful" signatures in the mid-IR. An essential feature of the study is an advanced system architecture that employs wavelength-division-multiplexed laser beams for high spectral fidelity and resolution. In addition, unlike conventional one-transmitter and one receiver design, the system is based on a scalable CDMA network concept with multiple transmitters and receivers to allow efficient information acquisition. The results suggest that multi-spectral laser imaging in general can be a unique and powerful technology for wide ranging applications.

  19. Tri-modal microscopy with multiphoton and optical coherence microscopy/tomography for multi-scale and multi-contrast imaging

    PubMed Central

    Chong, Shau Poh; Lai, Tom; Zhou, Yifeng; Tang, Shuo

    2013-01-01

    Multi-scale multimodal microscopy is a very useful technique by providing multiple imaging contrasts with adjustable field of views and spatial resolutions. Here, we present a tri-modal microscope combining multiphoton microscopy (MPM), optical coherence microscopy (OCM) and optical coherence tomography (OCT) for subsurface visualization of biological tissues. The advantages of the tri-modal system are demonstrated on various biological samples. It enables the visualization of multiple intrinsic contrasts including scattering, two-photon excitation fluorescence (TPEF), and second harmonic generation (SHG). It also enables a rapid scanning over a large tissue area and a high resolution zoom-in for cellular-level structures on regions of interest. The tri-modal microscope can be important for label-free imaging to obtain a sufficient set of parameters for reliable sample analysis. PMID:24049679

  20. Compressive spectral imaging systems based on linear detector

    NASA Astrophysics Data System (ADS)

    Liu, Yanli; Zhong, Xiaoming; Zhao, Haibo; Li, Huan

    2015-08-01

    The spectrometers capture large amount of raw and 3-dimensional (3D) spatial-spectral scene information with 2- dimensional (2D) focal plane arrays(FPA). In many applications, including imaging system and video cameras, the Nyquist rate is so high that too many samples result, making compression a precondition to storage or transmission. Compressive sensing theory employs non-adaptive linear projections that preserve the structure of the signal, the signal is then reconstructed from these projections using an optimization process. This article overview the fundamental spectral imagers based on compressive sensing, the coded aperture snapshot spectral imagers (CASSI) and high-resolution imagers via moving random exposure. Besides that, the article propose a new method to implement spectral imagers with linear detector imager systems based on spectrum compressed. The article describes the system introduction and code process, and it illustrates results with real data and imagery. Simulations are shown to illustrate the performance improvement attained by the new model and complexity of the imaging system greatly reduced by using linear detector.

  1. Hyperspectral image classifier based on beach spectral feature

    NASA Astrophysics Data System (ADS)

    Liang, Zhang; Lianru, Gao; Bing, Zhang

    2014-03-01

    The seashore, especially coral bank, is sensitive to human activities and environmental changes. A multispectral image, with coarse spectral resolution, is inadaptable for identify subtle spectral distinctions between various beaches. To the contrary, hyperspectral image with narrow and consecutive channels increases our capability to retrieve minor spectral features which is suit for identification and classification of surface materials on the shore. Herein, this paper used airborne hyperspectral data, in addition to ground spectral data to study the beaches in Qingdao. The image data first went through image pretreatment to deal with the disturbance of noise, radiation inconsistence and distortion. In succession, the reflection spectrum, the derivative spectrum and the spectral absorption features of the beach surface were inspected in search of diagnostic features. Hence, spectra indices specific for the unique environment of seashore were developed. According to expert decisions based on image spectrums, the beaches are ultimately classified into sand beach, rock beach, vegetation beach, mud beach, bare land and water. In situ surveying reflection spectrum from GER1500 field spectrometer validated the classification production. In conclusion, the classification approach under expert decision based on feature spectrum is proved to be feasible for beaches.

  2. Spatially resolved spectral-imaging device

    DOEpatents

    Bloom, Joshua Simon; Tyson, John Anthony

    2016-02-09

    A spatially resolved spectral device comprising a dispersive array to receive an incident light comprising a principal ray. The dispersive array comprising a plurality of dichroic layers, each of the plurality of dichroic layers disposed in a path of a direction of the principal ray. Each of the plurality of dichroic layers configured to at least one of reflect or transmit a different wavelength range of the incident light. The device further comprising a detection array operatively coupled with the dispersive array. The detection array comprising a photosensitive component including a plurality of detection pixels, each of the plurality of detection pixels having a light-receiving surface disposed parallel to the direction of the principal ray to detect a respective one of the different wavelength ranges of incident light reflected from a corresponding one of the plurality of dichroic layers.

  3. Multiphoton microscopy in defining liver function

    NASA Astrophysics Data System (ADS)

    Thorling, Camilla A.; Crawford, Darrell; Burczynski, Frank J.; Liu, Xin; Liau, Ian; Roberts, Michael S.

    2014-09-01

    Multiphoton microscopy is the preferred method when in vivo deep-tissue imaging is required. This review presents the application of multiphoton microscopy in defining liver function. In particular, multiphoton microscopy is useful in imaging intracellular events, such as mitochondrial depolarization and cellular metabolism in terms of NAD(P)H changes with fluorescence lifetime imaging microscopy. The morphology of hepatocytes can be visualized without exogenously administered fluorescent dyes by utilizing their autofluorescence and second harmonic generation signal of collagen, which is useful in diagnosing liver disease. More specific imaging, such as studying drug transport in normal and diseased livers are achievable, but require exogenously administered fluorescent dyes. If these techniques can be translated into clinical use to assess liver function, it would greatly improve early diagnosis of organ viability, fibrosis, and cancer.

  4. Time-resolved spectral imaging: better photon economy, higher accuracy

    NASA Astrophysics Data System (ADS)

    Fereidouni, Farzad; Reitsma, Keimpe; Blab, Gerhard A.; Gerritsen, Hans C.

    2015-03-01

    Lifetime and spectral imaging are complementary techniques that offer a non-invasive solution for monitoring metabolic processes, identifying biochemical compounds, and characterizing their interactions in biological tissues, among other tasks. Newly developed instruments that perform time-resolved spectral imaging can provide even more information and reach higher sensitivity than either modality alone. Here we report a multispectral lifetime imaging system based on a field-programmable gate array (FPGA), capable of operating at high photon count rates (12 MHz) per spectral detection channel, and with time resolution of 200 ps. We performed error analyses to investigate the effect of gate width and spectral-channel width on the accuracy of estimated lifetimes and spectral widths. Temporal and spectral phasors were used for analysis of recorded data, and we demonstrated blind un-mixing of the fluorescent components using information from both modalities. Fractional intensities, spectra, and decay curves of components were extracted without need for prior information. We further tested this approach with fluorescently doubly-labeled DNA, and demonstrated its suitability for accurately estimating FRET efficiency in the presence of either non-interacting or interacting donor molecules.

  5. Spectral characterization of storage phosphor imaging plates

    SciTech Connect

    Deresch, A.; Jechow, M.; Gollwitzer, C.

    2014-02-18

    This work presents attenuation and sensitivity measurements of radiographic imaging plates (IPs) with quasimonoenergetic X-rays in the 8–60 kiloelectronvolt range. The measurements are used to validate theoretical predictions. A short overview of the theoretical model is given. The model can be used to describe the sensitivity of different detector types to a wide range of X-ray energies.

  6. Imaging crystal/spectral line search

    SciTech Connect

    Koch, J.A.

    1998-02-16

    The following table is a compilation of chance coincidences between x- ray line wavelengths and crystal planes which will reflect those wavelengths near normal incidence. The motivation is to explore the possibilities for expanding the range of choices for near normal incidence x-ray crystal imaging.

  7. Multi-spectral image dissector camera system

    NASA Technical Reports Server (NTRS)

    1972-01-01

    The image dissector sensor for the Earth Resources Program is evaluated using contrast and reflectance data. The ground resolution obtainable for low contrast at the targeted signal to noise ratio of 1.8 was defined. It is concluded that the system is capable of achieving the detection of small, low contrast ground targets from satellites.

  8. Multiple-image encryption using spectral cropping and spatial multiplexing

    NASA Astrophysics Data System (ADS)

    Deng, Pingke; Diao, Ming; Shan, Mingguang; Zhong, Zhi; Zhang, Yabin

    2016-01-01

    A multiple-image encryption scheme is proposed using spectral cropping and space multiplexing based on discrete multiple-parameter fractional Fourier transform (DMPFRFT). Spectrum of each original image is firstly cropped by a low-pass filter, and the image is then recovered with the same size of the filter. The recovered images are spatially shifted and multiplexed into a complex signal with the same size of original image. The complex signal is multiplied by a pixel scrambling operation and random phase mask, and then encrypted into one image by DMPFRFT. The multiplexing images can be retrieved with correct keys, and the original images can be then obtained by enlarging the demultiplexing images. Numerical simulations have been done to demonstrate the validity and the security of the proposed method.

  9. Water Body Extraction from Multi Spectral Image by Spectral Pattern Analysis

    NASA Astrophysics Data System (ADS)

    Nguyen, D. D.

    2012-07-01

    Water is one of the vital components of the Earth environment which needs to be frequently monitored. Satellite multispectral remote sensing image has been used over decades for water body extraction. Methodology of water body extraction can be summarized to three groups: feature extraction, supervised and unsupervised classification and data fusion. These methods, however, are of pure mathematical and statistical approach and little of them explore essential characteristics of multispectral image which is based on ground object radiance absorption behaviour in each sensing spectral bands. The spectral absorption characteristics of water body in visible and infrared bands differ very much from the other ground objects. They depend only on the used spectral bands and can be considered as invariant and sensor independent. In this paper the author proposed an application of spectral pattern analysis for water body extraction using spectral bands green, red, near infrared NIR and short wave infrared SWIR. The proposed algorithm has been used for water body extraction by Spot 5 and Landsat 5 TM images. Ground truth validation was carried out in Hanoi City. The advantage of this algorithm does not base on water body extraction only but it allows to asses also water quality. Different level of turbidity and organic matter contents could be classified by using additional index.

  10. Face Recognition with Multi-Resolution Spectral Feature Images

    PubMed Central

    Sun, Zhan-Li; Lam, Kin-Man; Dong, Zhao-Yang; Wang, Han; Gao, Qing-Wei; Zheng, Chun-Hou

    2013-01-01

    The one-sample-per-person problem has become an active research topic for face recognition in recent years because of its challenges and significance for real-world applications. However, achieving relatively higher recognition accuracy is still a difficult problem due to, usually, too few training samples being available and variations of illumination and expression. To alleviate the negative effects caused by these unfavorable factors, in this paper we propose a more accurate spectral feature image-based 2DLDA (two-dimensional linear discriminant analysis) ensemble algorithm for face recognition, with one sample image per person. In our algorithm, multi-resolution spectral feature images are constructed to represent the face images; this can greatly enlarge the training set. The proposed method is inspired by our finding that, among these spectral feature images, features extracted from some orientations and scales using 2DLDA are not sensitive to variations of illumination and expression. In order to maintain the positive characteristics of these filters and to make correct category assignments, the strategy of classifier committee learning (CCL) is designed to combine the results obtained from different spectral feature images. Using the above strategies, the negative effects caused by those unfavorable factors can be alleviated efficiently in face recognition. Experimental results on the standard databases demonstrate the feasibility and efficiency of the proposed method. PMID:23418451

  11. Test and analysis of spectral response for UV image intensifier

    NASA Astrophysics Data System (ADS)

    Qian, Yunsheng; Liu, Jian; Feng, Cheng; Lv, Yang; Zhang, Yijun

    2015-10-01

    The UV image intensifier is one kind of electric vacuum imaging device based on principle of photoelectronic imaging. To achieve solar-blind detection, its spectral response characteristic is extremely desirable. A broad spectrum response measurement system is developed. This instrument uses EQ-99 laser-driven light source to get broad spectrum in the range of 200 nm to 1700 nm. A special preamplifier as well as a test software is work out. The spectral response of the image intensifier can be tested in the range of 200~1700 nm. Using this spectrum response measuring instrument, the UV image intensifiers are tested. The spectral response at the spectral range of 200 nm to 600 nm are obtained. Because of the quantum efficiency of Te-Cs photocathode used in image intens ifier above 280nm wavelength still exists, especially at 280 nm to 320nm.Therefore, high-performance UV filters is required for solar blind UV detection. Based on two sets of UV filters, the influence of solar radiation on solar blind detection is calculated and analyzed.

  12. Image completion by diffusion maps and spectral relaxation.

    PubMed

    Gepshtein, Shai; Keller, Yosi

    2013-08-01

    We present a framework for image inpainting that utilizes the diffusion framework approach to spectral dimensionality reduction. We show that on formulating the inpainting problem in the embedding domain, the domain to be inpainted is smoother in general, particularly for the textured images. Thus, the textured images can be inpainted through simple exemplar-based and variational methods. We discuss the properties of the induced smoothness and relate it to the underlying assumptions used in contemporary inpainting schemes. As the diffusion embedding is nonlinear and noninvertible, we propose a novel computational approach to approximate the inverse mapping from the inpainted embedding space to the image domain. We formulate the mapping as a discrete optimization problem, solved through spectral relaxation. The effectiveness of the presented method is exemplified by inpainting real images, where it is shown to compare favorably with contemporary state-of-the-art schemes. PMID:23322762

  13. Spectral imaging detects breast cancer in fresh unstained specimens

    NASA Astrophysics Data System (ADS)

    Chung, Alice; Gaon, Mark; Jeong, Jihoon; Karlan, Scott; Lindsley, Erik; Wachsmann-Hogiu, Sebastian; Xiong, Yizhi; Zhao, Tong; Farkas, Daniel L.

    2006-02-01

    Spectral imaging has recently been introduced in the biomedical field as a noninvasive, quantitative means of studying biological tissues. Many of its potential applications have been demonstrated (in vitro and, to a lesser degree, in vivo) with the use of stains or dyes. Successful translation to the clinical environment has been largely lagging, due to safety considerations and regulatory limitations preventing use of contrast agents in humans. We report experiments showing the feasibility of high-resolution spectral imaging of breast cancer without the use of contrast agents, thus completing the continuum of translational research, to in vivo imaging that will be directly applicable in the clinical environment. Our initial work focused on image acquisition using Fourier transform microinterferometry and subsequent segmentation of both stained and unstained breast cancer slides-derived image sets. We then applied our techniques to imaging fresh unstained ex vivo specimens of rat breast cancer and sentinel lymph nodes. We also investigated multiple methods of classification to optimize our image analyses, and preliminary results for the best algorithm tested yielded an overall sensitivity of 96%, and a specificity of 92% for cancer detection. Using spectral imaging and classification techniques, we were able to demonstrate that reliable detection of breast cancer in fixed and fresh unstained specimens of breast tissue is possible.

  14. Spectral imaging of mouse calvaria undergoing craniosynstosis

    NASA Astrophysics Data System (ADS)

    Crane, Nicole J.; Wang, Wei; Ignelzi, Michael A., Jr.; Morris, Michael D.

    2003-07-01

    Craniosynostosis, the premature fusion of the skull bones at the sutures, is the second most common human birth defect that affects the face and skull. The top most flat bones that comprise the skull, or calvaria, are most often affected. We previously showed that treatment of mouse calvaria with FGF2-soaked beads leads to craniosynostosis. In this study we treated mouse calvaria with FGF2-soaked beads and then used Raman imaging to demonstrate the spatial distribution of apatitic mineral and matrix in the sutures. There was no difference between FGF2 treated and control calvaria in the type of mineral produced (a lightly carbonated apatite), however we did observe increased mineral deposition in FGF2 treated calvaria. Raman imaging has great promise to detect the earliest mineral and matrix changes that occur in craniosynostosis.

  15. Spectral Imaging for Intracranial Stents and Stent Lumen

    PubMed Central

    Chen, David Yen-Ting; Chen, Chi-Jen; Hsu, Hui-Ling

    2016-01-01

    Introduction Application of computed tomography for monitoring intracranial stents is limited because of stent-related artifacts. Our purpose was to evaluate the effect of gemstone spectral imaging on the intracranial stent and stent lumen. Materials and Methods In vitro, we scanned Enterprise stent phantom and a stent–cheese complex using the gemstone spectral imaging protocol. Follow-up gemstone spectral images of 15 consecutive patients with placement of Enterprise from January 2013 to September 2014 were also retrospectively reviewed. We used 70-keV, 140-keV, iodine (water), iodine (calcium), and iodine (hydroxyapatite) images to evaluate their effect on the intracranial stent and stent lumen. Two regions of interest were individually placed in stent lumen and adjacent brain tissue. Contrast-to-noise ratio was measured to determine image quality. The maximal diameter of stent markers was also measured to evaluate stent-related artifact. Two radiologists independently graded the visibility of the lumen at the maker location by using a 4-point scale. The mean of grading score, contrast/noise ratio and maximal diameter of stent markers were compared among all modes. All results were analyzed by SPSS version 20. Results In vitro, iodine (water) images decreased metallic artifact of stent makers to the greatest degree. The most areas of cheese were observed on iodine (water) images. In vivo, iodine (water) images had the smallest average diameter of stent markers (0.33 ± 0.17mm; P < .05) and showed the highest mean grading score (2.94 ± 0.94; P < .05) and contrast/noise ratio of in-stent lumen (160.03 ±37.79; P < .05) among all the modes. Conclusion Iodine (water) images can help reduce stent-related artifacts of Enterprise and enhance contrast of in-stent lumen. Spectral imaging may be considered a noninvasive modality for following-up patients with in-stent stenosis. PMID:26731534

  16. Spectral mixture analysis of multispectral thermal infrared images

    NASA Technical Reports Server (NTRS)

    Gillespie, Alan R.

    1992-01-01

    Remote spectral measurements of light reflected or emitted from terrestrial scenes is commonly integrated over areas sufficiently large that the surface comprises more than one component. Techniques have been developed to analyze multispectral or imaging spectrometer data in terms of a wide range of mixtures of a limited number of components. Spectral mixture analysis has been used primarily for visible and near-infrared images, but it may also be applied to thermal infrared data. Two approaches are reviewed: binary mixing and a more general treatment for isothermal mixtures of a greater number of components.

  17. Spectral imaging in preclinical research and clinical pathology.

    PubMed

    Levenson, Richard; Beechem, Joseph; McNamara, George

    2012-01-01

    Spectral imaging methods are attracting increased interest from researchers and practitioners in basic science, pre-clinical and clinical arenas. A combination of better labeling reagents and better optics creates opportunities to detect and measure multiple parameters at the molecular and cellular level. These tools can provide valuable insights into the basic mechanisms of life, and yield diagnostic and prognostic information for clinical applications. There are many multispectral technologies available, each with its own advantages and limitations. This chapter will present an overview of the rationale for spectral imaging, and discuss the hardware, software and sample labeling strategies that can optimize its usefulness in clinical settings. PMID:22475632

  18. Spectral imaging in preclinical research and clinical pathology.

    PubMed

    Levenson, Richard; Beechem, Joseph; McNamara, George

    2013-01-01

    Spectral imaging methods are attracting increased interest from researchers and practitioners in basic science, preclinical and clinical arenas. A combination of better labeling reagents and better optics creates opportunities to detect and measure multiple parameters at the molecular and cellular level. These tools can provide valuable insights into the basic mechanisms of life, and yield diagnostic and prognostic information for clinical applications. There are many multispectral technologies available, each with its own advantages and limitations. This chapter will present an overview of the rationale for spectral imaging, and discuss the hardware, software and sample labeling strategies that can optimize its usefulness in clinical settings. PMID:23542931

  19. Hyper-spectral imaging using an optical fiber transition element

    NASA Astrophysics Data System (ADS)

    Bush, Brett C.; Otten, Leonard J., III; Schmoll, Juergen

    2007-09-01

    The Bi-static Optical Imaging Sensor (BOIS) is a 2-D imaging sensor that operates in the short-wave infra-red (SWIR) spectral regime over wavelengths from approximately 1.0 to 2.4 microns. The conceptual design of the sensor is based on integral field spectroscopy techniques. The BOIS sensor utilizes a fiber transition element consisting of multiple optical fibers to map the 2-D spatial input scene into a 1-D linear array for injection into a hyper-spectral imaging (HSI) sensor. The HSI spectrometer acquires fast time resolution snapshots (60 Hz) of the entire input target scene in numerous narrowband spectral channels covering the SWIR spectral band. The BOIS sensor is developed to spatially observe the fast time-evolving radiative signature of targets over a variety of spectral bands, thus simultaneously characterizing the overall scene in four dimensions: 2 spatial, wavelength, and time. We describe the successful design, operation, and testing of a laboratory prototype version of the BOIS sensor as well as further development of a field version of the sensor. The goal of the laboratory prototype BOIS sensor was to validate the proof-of-concept ability in the 4-D measurement concept of this unique design. We demonstrate the 2-D spatial remapping of the input scene (using SWIR laser and blackbody cavity sources) in multiple spectral channels from the spatial versus spectral pixel output of the HSI snapshot. We also describe algorithms developed in the data processing to retrieve temperatures of the observation scene from the hyper-spectral measurements.

  20. Some simple mechanisms of multiphoton excitation in many - level systems

    NASA Astrophysics Data System (ADS)

    Donley, E. A.; Marquardt, R.; Quack, M.; Stohner, J.; Thanopulos, I.; Wallenborn, E.-U.

    Results are reported on coherent monochromatic multiphoton excitation in many-level systems, which are representative for some of the basic mechanisms for atomic and molecular multiphoton processes. Numerical solutions are discussed that use the Floquet and quasiresonant approximations in the framework of the URIMIR program package. The excitation schemes include direct three-photon excitation, two-photon excitation with diagonal coupling, Göppert-Mayer-type two-photon processes, multiphoton excitation with off-resonant intermediates, and practically irreversible coherent excitation into dense spectral structures. Several interesting phenomena are observed, such as nonlinear line shifts and broadenings of multiphoton resonances of relevance for multiphoton spectroscopy and almost constant intermediate population inversions, potentially useful for laser design. The accurate numerical results are compared with approximate solutions from perturbation theory, and with simple analytical solutions from Rabi-type formulae.

  1. Surface science capabilities from IMP spectral imaging

    NASA Technical Reports Server (NTRS)

    Singer, Robert B.

    1994-01-01

    The Imager for Mars Pathfinder (IMP) had a single 12-position filter wheel for one of its two 'eyes'. Originally eight, and then nine, of these filters were optimized for surface science, and three narrow-band filters for atmospheric science. Because of some design revisions we will now have filter wheels on both sides. The wheels for right and left eyes are identical, 12 filter positions each, and rigidly linked to the same rotation shaft. There are now 13 surface filters, in addition to 5 for atmospheric observations. Details of all the filter positions are tabulated and approximate gaussian bandpasses for the 13 surface filters are shown.

  2. Specialized Color Targets for Spectral Reflectance Reconstruction of Magnified Images

    NASA Astrophysics Data System (ADS)

    Kruschwitz, Jennifer D. T.

    Digital images are used almost exclusively instead of film to capture visual information across many scientific fields. The colorimetric color representation within these digital images can be relayed from the digital counts produced by the camera with the use of a known color target. In image capture of magnified images, there is currently no reliable color target that can be used at multiple magnifications and give the user a solid understanding of the color ground truth within those images. The first part of this dissertation included the design, fabrication, and testing of a color target produced with optical interference coated microlenses for use in an off-axis illumination, compound microscope. An ideal target was designed to increase the color gamut for colorimetric imaging and provide the necessary "Block Dye" spectral reflectance profiles across the visible spectrum to reduce the number of color patches necessary for multiple filter imaging systems that rely on statistical models for spectral reflectance reconstruction. There are other scientific disciplines that can benefit from a specialized color target to determine the color ground truth in their magnified images and perform spectral estimation. Not every discipline has the luxury of having a multi-filter imaging system. The second part of this dissertation developed two unique ways of using an interference coated color mirror target: one that relies on multiple light-source angles, and one that leverages a dynamic color change with time. The source multi-angle technique would be used for the microelectronic discipline where the reconstructed spectral reflectance would be used to determine a dielectric film thickness on a silicon substrate, and the time varying technique would be used for a biomedical example to determine the thickness of human tear film.

  3. Molecular application of spectral photoacoustic imaging in pancreatic cancer pathology

    NASA Astrophysics Data System (ADS)

    Lakshman, Minalini; Hupple, Clinton; Lohse, Ines; Hedley, David; Needles, Andrew; Theodoropoulos, Catherine

    2012-12-01

    Spectral imaging is an advanced photo-acoustic (PA) mode that can discern optical absorption of contrast agent(s) in the tissue micro-environment. This advancement is made possible by precise control of optical wavelength using a tunable pulsed laser, ranging from 680-970 nm. Differential optical absorption of blood oxygenation states makes spectral imaging of hemoglobin ideal to investigate remodeling of the tumor microenvironment- a molecular change that renders resistance to standard cancer treatment. Approach: Photo-acoustic imaging was performed on the Vevo® LAZR system (VisualSonics) at 5-20 Hz. Deep abdominal imaging was accomplished with a LZ250D probe at a center frequency of 21MHz and an axial resolution of 75 μm. The tumor model was generated in an immune compromised mouse by surgical implantation of primary patient derived tumors, in the pancreas. Results: Spectral imaging for oxygen saturation at 750 nm and 850 nm characterized this tumor with a poorly oxygenated core surrounded by a well oxygenated periphery. Multispectral imaging identified a sub region in the core with a four-fold signal exclusively at 750 and 800 nm. A co-registered 2D image of this region was shown to be echogenic and calcification was suspected. Perfusion imaging with contrast enhanced ultrasound using microbubbles (Vevo MicroMarker® contrast agents, VisualSonics) identified functional vessels towards this sub region. Histology confirmed calcification and vascularization in the tumor core. Taken together, non-invasive characterization of the tumor microenvironment using photo-acoustics rendered spectral imaging a sensitive tool to monitor molecular changes representative of progression of pancreatic cancer that kills within 6 months of diagnosis.

  4. Spectral Imaging from Uavs Under Varying Illumination Conditions

    NASA Astrophysics Data System (ADS)

    Hakala, T.; Honkavaara, E.; Saari, H.; Mäkynen, J.; Kaivosoja, J.; Pesonen, L.; Pölönen, I.

    2013-08-01

    Rapidly developing unmanned aerial vehicles (UAV) have provided the remote sensing community with a new rapidly deployable tool for small area monitoring. The progress of small payload UAVs has introduced greater demand for light weight aerial payloads. For applications requiring aerial images, a simple consumer camera provides acceptable data. For applications requiring more detailed spectral information about the surface, a new Fabry-Perot interferometer based spectral imaging technology has been developed. This new technology produces tens of successive images of the scene at different wavelength bands in very short time. These images can be assembled in spectral data cubes with stereoscopic overlaps. On field the weather conditions vary and the UAV operator often has to decide between flight in sub optimal conditions and no flight. Our objective was to investigate methods for quantitative radiometric processing of images taken under varying illumination conditions, thus expanding the range of weather conditions during which successful imaging flights can be made. A new method that is based on insitu measurement of irradiance either in UAV platform or in ground was developed. We tested the methods in a precision agriculture application using realistic data collected in difficult illumination conditions. Internal homogeneity of the original image data (average coefficient of variation in overlapping images) was 0.14-0.18. In the corrected data, the homogeneity was 0.10-0.12 with a correction based on broadband irradiance measured in UAV, 0.07-0.09 with a correction based on spectral irradiance measurement on ground, and 0.05-0.08 with a radiometric block adjustment based on image data. Our results were very promising, indicating that quantitative UAV based remote sensing could be operational in diverse conditions, which is prerequisite for many environmental remote sensing applications.

  5. Fourier Spectral Filter Array for Optimal Multispectral Imaging.

    PubMed

    Jia, Jie; Barnard, Kenneth J; Hirakawa, Keigo

    2016-04-01

    Limitations to existing multispectral imaging modalities include speed, cost, range, spatial resolution, and application-specific system designs that lack versatility of the hyperspectral imaging modalities. In this paper, we propose a novel general-purpose single-shot passive multispectral imaging modality. Central to this design is a new type of spectral filter array (SFA) based not on the notion of spatially multiplexing narrowband filters, but instead aimed at enabling single-shot Fourier transform spectroscopy. We refer to this new SFA pattern as Fourier SFA, and we prove that this design solves the problem of optimally sampling the hyperspectral image data. PMID:26849867

  6. Infrared hollow optical fiber probes for reflectance spectral imaging.

    PubMed

    Huang, Chenhui; Kino, Saiko; Katagiri, Takashi; Matsuura, Yuji

    2015-05-10

    Systems for infrared reflectance imaging are built with an FT-IR spectrometer, hollow optical fibers, and a high-speed infrared camera. To obtain reflectance images of biological samples, an optical fiber probe equipped with a light source at the distal end and a hybrid fiber probe composed of fibers for beam radiation and ones for image detection have been developed. By using these systems, reflectance spectral images of lipid painted on biomedical hard tissue, which provides reflectance of around 4%, are successfully acquired. PMID:25967522

  7. Comparison of in vivo and ex vivo laser scanning microscopy and multiphoton tomography application for human and porcine skin imaging

    SciTech Connect

    Darvin, M E; Richter, H; Zhu, Y J; Meinke, M C; Knorr, F; Lademann, J; Gonchukov, S A; Koenig, K

    2014-07-31

    Two state-of-the-art microscopic optical methods, namely, confocal laser scanning microscopy in the fluorescence and reflectance regimes and multiphoton tomography in the autofluorescence and second harmonic generation regimes, are compared for porcine skin ex vivo and healthy human skin in vivo. All skin layers such as stratum corneum (SC), stratum spinosum (SS), stratum basale (SB), papillary dermis (PD) and reticular dermis (RD) as well as transition zones between these skin layers are measured noninvasively at a high resolution, using the above mentioned microscopic methods. In the case of confocal laser scanning microscopy (CLSM), measurements in the fluorescence regime were performed by using a fluorescent dye whose topical application on the surface is well suited for the investigation of superficial SC and characterisation of the skin barrier function. For investigations of deeply located skin layers, such as SS, SB and PD, the fluorescent dye must be injected into the skin, which markedly limits fluorescence measurements using CLSM. In the case of reflection CLSM measurements, the obtained results can be compared to the results of multiphoton tomography (MPT) for all skin layers excluding RD. CLSM cannot distinguish between dermal collagen and elastin measuring their superposition in the RD. By using MPT, it is possible to analyse the collagen and elastin structures separately, which is important for the investigation of anti-aging processes. The resolution of MPT is superior to CLSM. The advantages and limitations of both methods are discussed and the differences and similarities between human and porcine skin are highlighted. (laser biophotonics)

  8. Comparison of in vivo and ex vivo laser scanning microscopy and multiphoton tomography application for human and porcine skin imaging

    NASA Astrophysics Data System (ADS)

    Darvin, M. E.; Richter, H.; Zhu, Y. J.; Meinke, M. C.; Knorr, F.; Gonchukov, S. A.; Koenig, K.; Lademann, J.

    2014-07-01

    Two state-of-the-art microscopic optical methods, namely, confocal laser scanning microscopy in the fluorescence and reflectance regimes and multiphoton tomography in the autofluorescence and second harmonic generation regimes, are compared for porcine skin ex vivo and healthy human skin in vivo. All skin layers such as stratum corneum (SC), stratum spinosum (SS), stratum basale (SB), papillary dermis (PD) and reticular dermis (RD) as well as transition zones between these skin layers are measured noninvasively at a high resolution, using the above mentioned microscopic methods. In the case of confocal laser scanning microscopy (CLSM), measurements in the fluorescence regime were performed by using a fluorescent dye whose topical application on the surface is well suited for the investigation of superficial SC and characterisation of the skin barrier function. For investigations of deeply located skin layers, such as SS, SB and PD, the fluorescent dye must be injected into the skin, which markedly limits fluorescence measurements using CLSM. In the case of reflection CLSM measurements, the obtained results can be compared to the results of multiphoton tomography (MPT) for all skin layers excluding RD. CLSM cannot distinguish between dermal collagen and elastin measuring their superposition in the RD. By using MPT, it is possible to analyse the collagen and elastin structures separately, which is important for the investigation of anti-aging processes. The resolution of MPT is superior to CLSM. The advantages and limitations of both methods are discussed and the differences and similarities between human and porcine skin are highlighted.

  9. Spectral image analysis of mutual illumination between florescent objects.

    PubMed

    Tominaga, Shoji; Kato, Keiji; Hirai, Keita; Horiuchi, Takahiko

    2016-08-01

    This paper proposes a method for modeling and component estimation of the spectral images of the mutual illumination phenomenon between two fluorescent objects. First, we briefly describe the bispectral characteristics of a single fluorescent object, which are summarized as a Donaldson matrix. We suppose that two fluorescent objects with different bispectral characteristics are located close together under a uniform illumination. Second, we model the mutual illumination between two objects. It is shown that the spectral composition of the mutual illumination is summarized with four components: (1) diffuse reflection, (2) diffuse-diffuse interreflection, (3) fluorescent self-luminescence, and (4) interreflection by mutual fluorescent illumination. Third, we develop algorithms for estimating the spectral image components from the observed images influenced by the mutual illumination. When the exact Donaldson matrices caused by the mutual illumination influence are unknown, we have to solve a non-linear estimation problem to estimate both the spectral functions and the location weights. An iterative algorithm is then proposed to solve the problem based on the alternate estimation of the spectral functions and the location weights. In our experiments, the feasibility of the proposed method is shown in three cases: the known Donaldson matrices, weak interreflection, and strong interreflection. PMID:27505645

  10. Spatial and spectral performance of a chromotomosynthetic hyperspectral imaging system.

    PubMed

    Bostick, Randall L; Perram, Glen P

    2012-03-01

    The spatial and spectral resolutions achievable by a prototype rotating prism chromotomosynthetic imaging (CTI) system operating in the visible spectrum are described. The instrument creates hyperspectral imagery by collecting a set of 2D images with each spectrally projected at a different rotation angle of the prism. Mathematical reconstruction techniques that have been well tested in the field of medical physics are used to reconstruct the data to produce the 3D hyperspectral image. The instrument operates with a 100 mm focusing lens in the spectral range of 400-900 nm with a field of view of 71.6 mrad and angular resolution of 0.8-1.6 μrad. The spectral resolution is 0.6 nm at the shortest wavelengths, degrading to over 10 nm at the longest wavelengths. Measurements using a point-like target show that performance is limited by chromatic aberration. The system model is slightly inaccurate due to poor estimation of detector spatial resolution, this is corrected based on results improving model performance. As with traditional dispersion technology, calibration of the transformed wavelength axis is required, though with this technology calibration improves both spectral and spatial resolution. While this prototype does not operate at high speeds, components exist which will allow for CTI systems to generate hyperspectral video imagery at rates greater than 100 Hz. PMID:22462909

  11. Spatial and spectral performance of a chromotomosynthetic hyperspectral imaging system

    NASA Astrophysics Data System (ADS)

    Bostick, Randall L.; Perram, Glen P.

    2012-03-01

    The spatial and spectral resolutions achievable by a prototype rotating prism chromotomosynthetic imaging (CTI) system operating in the visible spectrum are described. The instrument creates hyperspectral imagery by collecting a set of 2D images with each spectrally projected at a different rotation angle of the prism. Mathematical reconstruction techniques that have been well tested in the field of medical physics are used to reconstruct the data to produce the 3D hyperspectral image. The instrument operates with a 100 mm focusing lens in the spectral range of 400-900 nm with a field of view of 71.6 mrad and angular resolution of 0.8-1.6 μrad. The spectral resolution is 0.6 nm at the shortest wavelengths, degrading to over 10 nm at the longest wavelengths. Measurements using a point-like target show that performance is limited by chromatic aberration. The system model is slightly inaccurate due to poor estimation of detector spatial resolution, this is corrected based on results improving model performance. As with traditional dispersion technology, calibration of the transformed wavelength axis is required, though with this technology calibration improves both spectral and spatial resolution. While this prototype does not operate at high speeds, components exist which will allow for CTI systems to generate hyperspectral video imagery at rates greater than 100 Hz.

  12. Spatial, Temporal and Spectral Satellite Image Fusion via Sparse Representation

    NASA Astrophysics Data System (ADS)

    Song, Huihui

    Remote sensing provides good measurements for monitoring and further analyzing the climate change, dynamics of ecosystem, and human activities in global or regional scales. Over the past two decades, the number of launched satellite sensors has been increasing with the development of aerospace technologies and the growing requirements on remote sensing data in a vast amount of application fields. However, a key technological challenge confronting these sensors is that they tradeoff between spatial resolution and other properties, including temporal resolution, spectral resolution, swath width, etc., due to the limitations of hardware technology and budget constraints. To increase the spatial resolution of data with other good properties, one possible cost-effective solution is to explore data integration methods that can fuse multi-resolution data from multiple sensors, thereby enhancing the application capabilities of available remote sensing data. In this thesis, we propose to fuse the spatial resolution with temporal resolution and spectral resolution, respectively, based on sparse representation theory. Taking the study case of Landsat ETM+ (with spatial resolution of 30m and temporal resolution of 16 days) and MODIS (with spatial resolution of 250m ~ 1km and daily temporal resolution) reflectance, we propose two spatial-temporal fusion methods to combine the fine spatial information of Landsat image and the daily temporal resolution of MODIS image. Motivated by that the images from these two sensors are comparable on corresponding bands, we propose to link their spatial information on available Landsat- MODIS image pair (captured on prior date) and then predict the Landsat image from the MODIS counterpart on prediction date. To well-learn the spatial details from the prior images, we use a redundant dictionary to extract the basic representation atoms for both Landsat and MODIS images based on sparse representation. Under the scenario of two prior Landsat

  13. Information-Efficient Spectral Imaging Sensor With Tdi

    DOEpatents

    Rienstra, Jeffrey L.; Gentry, Stephen M.; Sweatt, William C.

    2004-01-13

    A programmable optical filter for use in multispectral and hyperspectral imaging employing variable gain time delay and integrate arrays. A telescope focuses an image of a scene onto at least one TDI array that is covered by a multispectral filter that passes separate bandwidths of light onto the rows in the TDI array. The variable gain feature of the TDI array allows individual rows of pixels to be attenuated individually. The attenuations are functions of the magnitudes of the positive and negative components of a spectral basis vector. The spectral basis vector is constructed so that its positive elements emphasize the presence of a target and its negative elements emphasize the presence of the constituents of the background of the imaged scene. This system provides for a very efficient determination of the presence of the target, as opposed to the very data intensive data manipulations that are required in conventional hyperspectral imaging systems.

  14. Content-based hyperspectral image retrieval using spectral unmixing

    NASA Astrophysics Data System (ADS)

    Plaza, Antonio J.

    2011-11-01

    The purpose of content-based image retrieval (CBIR) is to retrieve, from real data stored in a database, information that is relevant to a query. A major challenge for the development of efficient CBIR systems in the context of hyperspectral remote sensing applications is how to deal with the extremely large volumes of data produced by current Earth-observing (EO) imaging spectrometers. The data resulting from EO campaigns often comprises many Gigabytes per flight. When multiple instruments or timelines are combined, this leads to the collection of massive amounts of data coming from heterogeneous sources, and these data sets need to be effectively stored, managed, shared and retrieved. Furthermore, the growth in size and number of hyperspectral data archives demands more sophisticated search capabilities to allow users to locate and reuse data acquired in the past. In this paper we develop a new strategy to effectively retrieve hyperspectral image data sets using spectral unmixing concepts. Spectral unmixing is a very important task for hyperspectral data exploitation since the spectral signatures collected in natural environments are invariably a mixture of the pure signatures of the various materials found within the spatial extent of the ground instantaneous field view of the imaging instrument. In this work, we use the information provided by spectral unmixing (i.e. the spectral endmembers and their corresponding abundances in the scene) as effective meta-data to develop a new CBIR system that can assist users in the task of efficiently searching hyperspectral image instances in large data repositories. The proposed approach is validated using a collection of 154 hyperspectral data sets (comprising seven full flightlines) gathered by NASA using the Airborne Visible Infra-Red Imaging Spectrometer (AVIRIS) over the World Trade Center (WTC) area in New York City during the last two weeks of September, 2001, only a few days after the terrorist attacks that

  15. Thermal infrared spectral imager for airborne science applications

    NASA Astrophysics Data System (ADS)

    Johnson, William R.; Hook, Simon J.; Mouroulis, Pantazis; Wilson, Daniel W.; Gunapala, Sarath D.; Hill, Cory J.; Mumolo, Jason M.; Realmuto, Vincent; Eng, Bjorn T.

    2009-05-01

    An airborne thermal hyperspectral imager is underdevelopment which utilizes the compact Dyson optical configuration and quantum well infrared photo detector (QWIP) focal plane array. The Dyson configuration uses a single monolithic prism-like grating design which allows for a high throughput instrument (F/1.6) with minimal ghosting, stray-light and large swath width. The configuration has the potential to be the optimal imaging spectroscopy solution unmanned aerial vehicles (UAV) due to its small form factor and relatively low power requirements. The planned instrument specifications are discussed as well as design trade-offs. Calibration testing results (noise equivalent temperature difference, spectral linearity and spectral bandwidth) and laboratory emissivity plots from samples are shown using an operational testbed unit which has similar specifications as the final airborne system. Field testing of the testbed unit was performed to acquire plots of emissivity for various known standard minerals (quartz). A comparison is made using data from the ASTER spectral library.

  16. Advances in Hyperspectral and Multispectral Image Fusion and Spectral Unmixing

    NASA Astrophysics Data System (ADS)

    Lanaras, C.; Baltsavias, E.; Schindler, K.

    2015-08-01

    In this work, we jointly process high spectral and high geometric resolution images and exploit their synergies to (a) generate a fused image of high spectral and geometric resolution; and (b) improve (linear) spectral unmixing of hyperspectral endmembers at subpixel level w.r.t. the pixel size of the hyperspectral image. We assume that the two images are radiometrically corrected and geometrically co-registered. The scientific contributions of this work are (a) a simultaneous approach to image fusion and hyperspectral unmixing, (b) enforcing several physically plausible constraints during unmixing that are all well-known, but typically not used in combination, and (c) the use of efficient, state-of-the-art mathematical optimization tools to implement the processing. The results of our joint fusion and unmixing has the potential to enable more accurate and detailed semantic interpretation of objects and their properties in hyperspectral and multispectral images, with applications in environmental mapping, monitoring and change detection. In our experiments, the proposed method always improves the fusion compared to competing methods, reducing RMSE between 4% and 53%.

  17. Hyperspectral imaging of bruises in the SWIR spectral region

    NASA Astrophysics Data System (ADS)

    Randeberg, Lise L.; Hernandez-Palacios, Julio

    2012-02-01

    Optical diagnostics of bruised skin might provide important information for characterization and age determination of such injuries. Hyperspectral imaging is one of the optical techniques that have been employed for bruise characterization. This technique combines high spatial and spectral resolution and makes it possible to study both chromophore signatures and -distributions in an injury. Imaging and spectroscopy in the visible spectral range have resulted in increased knowledge about skin bruises. So far the SWIR region has not been explored for this application. The main objective of the current study was to characterize bruises in the SWIR wavelength range. Hyperspectral images in the SWIR (950-2500nm ) and VNIR (400-850nm) spectral range were collected from 3 adult volunteers with bruises of known age. Data were collected over a period of 8 days. The data were analyzed using spectroscopic techniques and statistical image analysis. Preliminary results from the pilot study indicate that SWIR hyperspectral imaging might be an important supplement to imaging in the visible part of the spectrum. The technique emphasizes local edema and gives a possibility to visualize features that cannot easily be seen in the visible part of the spectrum.

  18. Retinal oxygen saturation evaluation by multi-spectral fundus imaging

    NASA Astrophysics Data System (ADS)

    Khoobehi, Bahram; Ning, Jinfeng; Puissegur, Elise; Bordeaux, Kimberly; Balasubramanian, Madhusudhanan; Beach, James

    2007-03-01

    Purpose: To develop a multi-spectral method to measure oxygen saturation of the retina in the human eye. Methods: Five Cynomolgus monkeys with normal eyes were anesthetized with intramuscular ketamine/xylazine and intravenous pentobarbital. Multi-spectral fundus imaging was performed in five monkeys with a commercial fundus camera equipped with a liquid crystal tuned filter in the illumination light path and a 16-bit digital camera. Recording parameters were controlled with software written specifically for the application. Seven images at successively longer oxygen-sensing wavelengths were recorded within 4 seconds. Individual images for each wavelength were captured in less than 100 msec of flash illumination. Slightly misaligned images of separate wavelengths due to slight eye motion were registered and corrected by translational and rotational image registration prior to analysis. Numerical values of relative oxygen saturation of retinal arteries and veins and the underlying tissue in between the artery/vein pairs were evaluated by an algorithm previously described, but which is now corrected for blood volume from averaged pixels (n > 1000). Color saturation maps were constructed by applying the algorithm at each image pixel using a Matlab script. Results: Both the numerical values of relative oxygen saturation and the saturation maps correspond to the physiological condition, that is, in a normal retina, the artery is more saturated than the tissue and the tissue is more saturated than the vein. With the multi-spectral fundus camera and proper registration of the multi-wavelength images, we were able to determine oxygen saturation in the primate retinal structures on a tolerable time scale which is applicable to human subjects. Conclusions: Seven wavelength multi-spectral imagery can be used to measure oxygen saturation in retinal artery, vein, and tissue (microcirculation). This technique is safe and can be used to monitor oxygen uptake in humans. This work

  19. Mesospheric nightglow spectral survey taken by the ISO spectral spatial imager on ATLAS 1

    NASA Technical Reports Server (NTRS)

    Owens, J. K.; Torr, D. G.; Torr, M. R.; Chang, T.; Fennelly, J. A.; Richards, P. G.; Morgan, M. F.; Baldridge, T. W.; Fellows, C. W.; Dougani, H.

    1993-01-01

    This paper reports the first comprehensive spectral survey of the mesospheric airglow between 260 and 832 nm taken by the Imaging Spectrometric Observatory on the ATLAS 1 mission. We select data taken in the spectral window between 275 and 300 nm to determine the variation with altitude of the Herzberg I bands originating from the vibrational levels v-prime = 3 to 8. These data provide the first spatially resolved spectral measurements of the system. The data are used to demonstrate that to within an uncertainty of +/- 10 percent, the vibrational distribution remains invariant with altitude. The deficit reported previously for the v-prime = 5 level is not observed although there is a suggestion of depletion in v-prime = 6. The data could be used to place tight constraints on the vibrational dependence of quenching rate coefficients, and on the abundance of atomic oxygen.

  20. Mesospheric nightglow spectral survey taken by the ISO spectral spatial imager on Atlas 1

    NASA Technical Reports Server (NTRS)

    Owens, J. K.; Torr, D. G.; Torr, M. R.; Chang, T.; Fennelly, J. A.; Richards, P. G.; Morgan, M. F.; Baldridge, T. W.; Dougani, H.; Swift, W.

    1993-01-01

    This paper reports the first comprehensive spectral survey of the mesospheric airglow between 260 and 832 nm taken by the Imaging Spectrometric Observatory (ISO) on the ATLAS I mission. We select data taken in the spectral window between 275 and 300 nm to determine the variation with altitude of the Herzberg I bands originating from the vibrational levels v' = 3 to 8. These data provide the first spatially resolved spectral measurements of the system. The data are used to demonstrate that to within an uncertainty of + 10%, the vibrational distribution remains invariant with altitude. The deficit reported previously for the v' = 5 level is not observed although there is a suggestion of depletion in v' = 6. The data could be used to place tight constraints on the vibrational dependence of quenching rate coefficients, and on the abundance of atomic oxygen.

  1. Experimental application of ultrafast imaging to spectral tissue characterization.

    PubMed

    Garcia-Duitama, Julian; Chayer, Boris; Han, Aiguo; Garcia, Damien; Oelze, Michael L; Cloutier, Guy

    2015-09-01

    Ultrasound ultrafast imaging (UI) allows acquisition of thousands of frames per second with a sustained image quality at any depth in the field of view. Therefore, it would be ideally suited to obtain good statistical sampling of fast-moving tissues using spectral-based techniques to derive the backscatter coefficient (BSC) and associated quantitative parameters. In UI, an image is formed by insonifying the medium with plane waves steered at different angles, beamforming them and compounding the resulting radiofrequency images. We aimed at validating, experimentally, the effect of these beamforming protocols on the BSC, under both isotropic and anisotropic conditions. Using UI techniques with a linear array transducer (5-14 MHz), we estimated the BSCs of tissue-mimicking phantoms and flowing porcine blood at depths up to 35 mm with a frame rate reaching 514 Hz. UI-based data were compared with those obtained using single-element transducers and conventional focusing imaging. Results revealed that UI compounded images can produce valid estimates of BSCs and effective scatterer size (errors less than 2.2 ± 0.8 and 0.26 ± 0.2 dB for blood and phantom experiments, respectively). This work also describes the use of pre-compounded UI images (i.e., steered images) to assess the angular dependency of circulating red blood cells. We have concluded that UI data sets can be used for BSC spectral tissue analysis and anisotropy characterization. PMID:26119459

  2. Rapid microscopy measurement of very large spectral images.

    PubMed

    Lindner, Moshe; Shotan, Zav; Garini, Yuval

    2016-05-01

    The spectral content of a sample provides important information that cannot be detected by the human eye or by using an ordinary RGB camera. The spectrum is typically a fingerprint of the chemical compound, its environmental conditions, phase and geometry. Thus measuring the spectrum at each point of a sample is important for a large range of applications from art preservation through forensics to pathological analysis of a tissue section. To date, however, there is no system that can measure the spectral image of a large sample in a reasonable time. Here we present a novel method for scanning very large spectral images of microscopy samples even if they cannot be viewed in a single field of view of the camera. The system is based on capturing information while the sample is being scanned continuously 'on the fly'. Spectral separation implements Fourier spectroscopy by using an interferometer mounted along the optical axis. High spectral resolution of ~5 nm at 500 nm could be achieved with a diffraction-limited spatial resolution. The acquisition time is fairly high and takes 6-8 minutes for a sample size of 10mm x 10mm measured under a bright-field microscope using a 20X magnification. PMID:27137565

  3. A pragmatic guide to multiphoton microscope design

    PubMed Central

    Young, Michael D.; Field, Jeffrey J.; Sheetz, Kraig E.; Bartels, Randy A.; Squier, Jeff

    2016-01-01

    Multiphoton microscopy has emerged as a ubiquitous tool for studying microscopic structure and function across a broad range of disciplines. As such, the intent of this paper is to present a comprehensive resource for the construction and performance evaluation of a multiphoton microscope that will be understandable to the broad range of scientific fields that presently exploit, or wish to begin exploiting, this powerful technology. With this in mind, we have developed a guide to aid in the design of a multiphoton microscope. We discuss source selection, optical management of dispersion, image-relay systems with scan optics, objective-lens selection, single-element light-collection theory, photon-counting detection, image rendering, and finally, an illustrated guide for building an example microscope. PMID:27182429

  4. Spectral imaging and biomedicine: new devices, new approaches

    SciTech Connect

    Levenson, Richard M.; Cronin, P. J.; Harvey, N. R.

    2002-01-01

    The advent of molecular medicine and new demands on pathologists to deliver prognostic and therapy-shaping analyses has created a need for enhanced imaging tools. Spectral imaging coupled wilh microscopy is a relatively novel and largely unexplored technology that holds out promise of satisfying, at least in part, such a need. New optical methods for spectral discrimination are being combined with powerful software approaches, often originally developed in diffbrent fields, to explore and exploit a wealth of informaticm beyond the capabilities of conventional color-based imaging approaches. Some of the new devices and software tools are described and illustrated here. While the results are indeed promising, it must be stressed that this field is in its infancy, and the optimal uses of this technology in the clinical arena still await definition.

  5. Quality assessment for spectral domain optical coherence tomography (OCT) images

    NASA Astrophysics Data System (ADS)

    Liu, Shuang; Paranjape, Amit S.; Elmaanaoui, Badr; Dewelle, Jordan; Rylander, H. Grady, III; Markey, Mia K.; Milner, Thomas E.

    2009-02-01

    Retinal nerve fiber layer (RNFL) thickness, a measure of glaucoma progression, can be measured in images acquired by spectral domain optical coherence tomography (OCT). The accuracy of RNFL thickness estimation, however, is affected by the quality of the OCT images. In this paper, a new parameter, signal deviation (SD), which is based on the standard deviation of the intensities in OCT images, is introduced for objective assessment of OCT image quality. Two other objective assessment parameters, signal to noise ratio (SNR) and signal strength (SS), are also calculated for each OCT image. The results of the objective assessment are compared with subjective assessment. In the subjective assessment, one OCT expert graded the image quality according to a three-level scale (good, fair, and poor). The OCT B-scan images of the retina from six subjects are evaluated by both objective and subjective assessment. From the comparison, we demonstrate that the objective assessment successfully differentiates between the acceptable quality images (good and fair images) and poor quality OCT images as graded by OCT experts. We evaluate the performance of the objective assessment under different quality assessment parameters and demonstrate that SD is the best at distinguishing between fair and good quality images. The accuracy of RNFL thickness estimation is improved significantly after poor quality OCT images are rejected by automated objective assessment using the SD, SNR, and SS.

  6. Testing of infrared image enhancing algorithm in different spectral bands

    NASA Astrophysics Data System (ADS)

    Dulski, R.; Sosnowski, T.; Kastek, M.; Trzaskawka, P.

    2012-06-01

    The paper presents results of testing the infrared image quality enhancing algorithm based on histogram processing. Testing were performed on real images registered in NIR, MWIR, and LWIR spectral bands. Infrared images are a very specific type of information. The perception and interpretation of such image depends not only on radiative properties of observed objects and surrounding scenery. Probably still most important are skills and experience of an observer itself. In practice, the optimal settings of the camera as well as automatic temperature range or contrast control do not guarantee the displayed images are optimal from observer's point of view. The solution to this are algorithms of image quality enhancing based on digital image processing methods. Such algorithms can be implemented inside the camera or applied later, after image registration. They must improve the visibility of low-contrast objects. They should also provide effective dynamic contrast control not only across entire image but also selectively to specific areas in order to maintain optimal visualization of observed scenery. In the paper one histogram equalization algorithm was tested. Adaptive nature of the algorithm should assure significant improvement of the image quality and the same effectiveness of object detection. Another requirement and difficulty is that it should also be effective for any given thermal image and it should not cause a visible image degradation in unpredictable situations. The application of tested algorithm is a promising alternative to a very effective but complex algorithms due to its low complexity and real time operation.

  7. Spectral analysis of mammographic images using a multitaper method

    SciTech Connect

    Wu Gang; Mainprize, James G.; Yaffe, Martin J.

    2012-02-15

    Purpose: Power spectral analysis in radiographic images is conventionally performed using a windowed overlapping averaging periodogram. This study describes an alternative approach using a multitaper technique and compares its performance with that of the standard method. This tool will be valuable in power spectrum estimation of images, whose content deviates significantly from uniform white noise. The performance of the multitaper approach will be evaluated in terms of spectral stability, variance reduction, bias, and frequency precision. The ultimate goal is the development of a useful tool for image quality assurance. Methods: A multitaper approach uses successive data windows of increasing order. This mitigates spectral leakage allowing one to calculate a reduced-variance power spectrum. The multitaper approach will be compared with the conventional power spectrum method in several typical situations, including the noise power spectra (NPS) measurements of simulated projection images of a uniform phantom, NPS measurement of real detector images of a uniform phantom for two clinical digital mammography systems, and the estimation of the anatomic noise in mammographic images (simulated images and clinical mammograms). Results: Examination of spectrum variance versus frequency resolution and bias indicates that the multitaper approach is superior to the conventional single taper methods in the prevention of spectrum leakage and variance reduction. More than four times finer frequency precision can be achieved with equivalent or less variance and bias. Conclusions: Without any shortening of the image data length, the bias is smaller and the frequency resolution is higher with the multitaper method, and the need to compromise in the choice of regions of interest size to balance between the reduction of variance and the loss of frequency resolution is largely eliminated.

  8. Online Unmixing of Multitemporal Hyperspectral Images Accounting for Spectral Variability

    NASA Astrophysics Data System (ADS)

    Thouvenin, Pierre-Antoine; Dobigeon, Nicolas; Tourneret, Jean-Yves

    2016-09-01

    Hyperspectral unmixing is aimed at identifying the reference spectral signatures composing an hyperspectral image and their relative abundance fractions in each pixel. In practice, the identified signatures may vary spectrally from an image to another due to varying acquisition conditions, thus inducing possibly significant estimation errors. Against this background, hyperspectral unmixing of several images acquired over the same area is of considerable interest. Indeed, such an analysis enables the endmembers of the scene to be tracked and the corresponding endmember variability to be characterized. Sequential endmember estimation from a set of hyperspectral images is expected to provide improved performance when compared to methods analyzing the images independently. However, the significant size of hyperspectral data precludes the use of batch procedures to jointly estimate the mixture parameters of a sequence of hyperspectral images. Provided that each elementary component is present in at least one image of the sequence, we propose to perform an online hyperspectral unmixing accounting for temporal endmember variability. The online hyperspectral unmixing is formulated as a two-stage stochastic program, which can be solved using a stochastic approximation. The performance of the proposed method is evaluated on synthetic and real data. A comparison with independent unmixing algorithms finally illustrates the interest of the proposed strategy.

  9. Online Unmixing of Multitemporal Hyperspectral Images Accounting for Spectral Variability.

    PubMed

    Thouvenin, Pierre-Antoine; Dobigeon, Nicolas; Tourneret, Jean-Yves

    2016-09-01

    Hyperspectral unmixing is aimed at identifying the reference spectral signatures composing a hyperspectral image and their relative abundance fractions in each pixel. In practice, the identified signatures may vary spectrally from an image to another due to varying acquisition conditions, thus inducing possibly significant estimation errors. Against this background, the hyperspectral unmixing of several images acquired over the same area is of considerable interest. Indeed, such an analysis enables the endmembers of the scene to be tracked and the corresponding endmember variability to be characterized. Sequential endmember estimation from a set of hyperspectral images is expected to provide improved performance when compared with methods analyzing the images independently. However, the significant size of the hyperspectral data precludes the use of batch procedures to jointly estimate the mixture parameters of a sequence of hyperspectral images. Provided that each elementary component is present in at least one image of the sequence, we propose to perform an online hyperspectral unmixing accounting for temporal endmember variability. The online hyperspectral unmixing is formulated as a two-stage stochastic program, which can be solved using a stochastic approximation. The performance of the proposed method is evaluated on synthetic and real data. Finally, a comparison with independent unmixing algorithms illustrates the interest of the proposed strategy. PMID:27305679

  10. Tunable acousto-optic spectral imager for atmospheric composition measurements in the visible spectral domain.

    PubMed

    Dekemper, Emmanuel; Loodts, Nicolas; Van Opstal, Bert; Maes, Jeroen; Vanhellemont, Filip; Mateshvili, Nina; Franssens, Ghislain; Pieroux, Didier; Bingen, Christine; Robert, Charles; De Vos, Lieve; Aballea, Ludovic; Fussen, Didier

    2012-09-01

    We describe a new spectral imaging instrument using a TeO(2) acousto-optical tunable filter (AOTF) operating in the visible domain (450-900 nm). It allows for fast (~1 second), monochromatic (FWHM ranges from 0.6 nm at 450 nm to 3.5 nm at 800 nm) picture acquisition with good spatial resolution. This instrument was designed as a breadboard of the visible channel of a new satellite-borne atmospheric limb spectral imager, named the Atmospheric Limb Tracker for the Investigation of the Upcoming Stratosphere (ALTIUS), that is currently being developed. We tested its remote sensing capabilities by observing the dense, turbulent plume exhausted by a waste incinerator stack at two wavelengths sensitive to NO(2). An average value of 6.0±0.4×10(17) molecules cm(-2) has been obtained for the NO(2) slant column density within the plume, close to the stack outlet. Although this result was obtained with a rather low accuracy, it demonstrates the potential of spectral imaging by using AOTFs in remote sensing. PMID:22945175

  11. Interpretation of AIS Images of Cuprite, Nevada Using Constraints of Spectral Mixtures

    NASA Technical Reports Server (NTRS)

    Smith, M. O.; Adams, J. B.

    1985-01-01

    A technique is outlined that tests the hypothesis Airborne Imaging Spectrometer (AIS) image spectra are produced by mixtures of surface materials. This technique allows separation of AIS images into concentration images of spectral endmembers (e.g., surface materials causing spectral variation). Using a spectral reference library it was possible to uniquely identify these spectral endmembers with respect to the reference library and to calibrate the AIS images.

  12. ISIS; An Information-efficient Spectral Imaging System

    SciTech Connect

    Boye, C.A.; Descour, M.R.; Gentry, S.M.; Grotbeck, C.L.; Stallard, B.R.; Sweatt, W.C.

    1998-07-19

    A specialized hyperspectral imager has been developed that preprocesses the spectra from an image before the light reaches the detectors. This "optical computer" does not allow the flexibility of digital post-processing. However, the processing is done in real time and the system can examine = 2 x 10{sup 6} scene pixels/sec. Therefore, outdoors it could search for pollutants, vegetation types, minerals, or man-made objects. On a high- speed production line it could identify defects in sheet products like plastic wrap or film, or on painted or plastic parts. ISIS is a line scan imager. A spectrally dispersed slit image is projected on a Spatial Light Modulator. The SLM is programmed to take the inner product of the spectral intensity vector and a spectral basis vector. The SLM directs the positive and negative parts of the inner product to different linear detector arrays so the signal difference equals the inner product. We envision a system with one telescope and =4 SLMS.

  13. Reflectance and Fluorescence Spectral Recovery via Actively Lit RGB Images.

    PubMed

    Fu, Ying; Lam, Antony; Sato, Imari; Okabe, Takahiro; Sato, Yoichi

    2016-07-01

    In recent years, fluorescence analysis of scenes has received attention in computer vision. Fluorescence can provide additional information about scenes, and has been used in applications such as camera spectral sensitivity estimation, 3D reconstruction, and color relighting. In particular, hyperspectral images of reflective-fluorescent scenes provide a rich amount of data. However, due to the complex nature of fluorescence, hyperspectral imaging methods rely on specialized equipment such as hyperspectral cameras and specialized illuminants. In this paper, we propose a more practical approach to hyperspectral imaging of reflective-fluorescent scenes using only a conventional RGB camera and varied colored illuminants. The key idea of our approach is to exploit a unique property of fluorescence: the chromaticity of fluorescent emissions are invariant under different illuminants. This allows us to robustly estimate spectral reflectance and fluorescent emission chromaticity. We then show that given the spectral reflectance and fluorescent chromaticity, the fluorescence absorption and emission spectra can also be estimated. We demonstrate in results that all scene spectra can be accurately estimated from RGB images. Finally, we show that our method can be used to accurately relight scenes under novel lighting. PMID:27295456

  14. Quantitative study on appearance of microvessels in spectral endoscopic imaging

    NASA Astrophysics Data System (ADS)

    Yamaguchi, Hiroshi; Saito, Takaaki; Shiraishi, Yasushi; Arai, Fumihito; Morimoto, Yoshinori; Yuasa, Atsuko

    2015-03-01

    Increase in abnormal microvessels in the superficial mucosa is often relevant to diagnostic findings of neoplasia in digestive endoscopy; hence, observation of superficial vasculature is crucial for cancer diagnosis. To enhance the appearance of such vessels, several spectral endoscopic imaging techniques have been developed, such as narrow-band imaging and blue laser imaging. Both techniques exploit narrow-band blue light for the enhancement. The emergence of such spectral imaging techniques has increased the importance of understanding the relation of the light wavelength to the appearance of superficial vasculature, and thus a new method is desired for quantitative analysis of vessel visibility in relation to the actual structure in the tissue. Here, we developed microvessel-simulating phantoms that allowed quantitative evaluation of the appearance of 15-μm-thick vessels. We investigated the relation between the vascular contrast and light wavelength by the phantom measurements and also verified it in experiments with swine, where the endoscopically observed vascular contrast was investigated together with its real vascular depth and diameter obtained by microscopic observation of fluorescence-labeled vessels. Our study indicates that changing the spectral property even in the wavelength range of blue light may allow selective enhancement of the vascular depth for clinical use.

  15. Study on monolithically integration miniaturized spectral imager by Fabry-Perot with Bragg stack

    NASA Astrophysics Data System (ADS)

    Liu, Shuyang; Zhou, Tao; Jia, Xiaodong; Cui, Hushan; Huang, Chengjun

    2016-01-01

    To break the limitation of the traditional spectral analysis system in low speed, high cost and huge size, this paper presents a CMOS-based monolithically miniaturized spectral system whose core component is the spectral imager. The idea of the spectral imager is to fabricate a spectral filter on top of the traditional CMOS imager. This paper designed a FP thin film filter consisted of Bragg stack as a mirror while both the material and the process is compatible with the CMOS imager fabrication. By the simulation, the filter is able to achieve a 2nm spectral resolution, which is a proof for the feasibility of the miniaturized spectral analysis system.

  16. Images and Spectral Performance of WFC3 Interference Filters

    NASA Technical Reports Server (NTRS)

    Quijada, Manuel A.; Boucarut, R.; Telfer, R.; Baggett, S.; Quijano, J. Kim; Allen, George; Arsenovic, Peter

    2006-01-01

    The Wide Field Camera 3 (WFC3) is a panchromatic imager that will be deployed in the Hubble Space Telescope (HST). The mission of the WFC3 is to enhance HST1s imaging capability in the ultraviolet, visible and near-infrared spectral regions. Together with a wavelength coverage spanning 2000A to 1.7 micron, the WFC3 high sensitivity, high spatial resolution, and large field-of-view provide the astronomer with an unprecedented set of tools for exploring all types of exciting astrophysical terrain and for addressing many key questions in astronomy today. The filter compliment, which includes broad, medium, and narrow band filters, naturally reflects the diversity of astronomical programs to be targeted with WFC3. The WFC3 holds 61 UVIS filters elements, 14 IR filters, and 3 dispersive elements. During ground testing, the majority of the UVIS filters were found to exhibit excellent performance consistent with or exceeding expectations; however, a subset of filters showed considerable ghost images; some with relative intensity as high as 10-15%. Replacement filters with band-defining coatings that substantially reduce these ghost images were designed and procured. A state-of-the-art characterization setup was developed to measured the intensity of ghost images, focal shift, wedge direction , transmitted uniformity and surface feature of filters that could effect uniform flat field images. We will report on this new filter characterization methods, as well as the spectral performance measurements of the in-band transmittance and blocking.

  17. LED-based endoscopic light source for spectral imaging

    NASA Astrophysics Data System (ADS)

    Browning, Craig M.; Mayes, Samuel; Favreau, Peter; Rich, Thomas C.; Leavesley, Silas J.

    2016-03-01

    Colorectal cancer is the United States 3rd leading cancer in death rates.1 The current screening for colorectal cancer is an endoscopic procedure using white light endoscopy (WLE). There are multiple new methods testing to replace WLE, for example narrow band imaging and autofluorescence imaging.2 However, these methods do not meet the need for a higher specificity or sensitivity. The goal for this project is to modify the presently used endoscope light source to house 16 narrow wavelength LEDs for spectral imaging in real time while increasing sensitivity and specificity. The process to do such was to take an Olympus CLK-4 light source, replace the light and electronics with 16 LEDs and new circuitry. This allows control of the power and intensity of the LEDs. This required a larger enclosure to house a bracket system for the solid light guide (lightpipe), three new circuit boards, a power source and National Instruments hardware/software for computer control. The results were a successfully designed retrofit with all the new features. The LED testing resulted in the ability to control each wavelength's intensity. The measured intensity over the voltage range will provide the information needed to couple the camera for imaging. Overall the project was successful; the modifications to the light source added the controllable LEDs. This brings the research one step closer to the main goal of spectral imaging for early detection of colorectal cancer. Future goals will be to connect the camera and test the imaging process.

  18. Spectrally resolved fluorescence imaging of human colonic adenomas.

    PubMed

    Chwirot, B W; Kowalska, M; Sypniewska, N; Michniewicz, Z; Gradziel, M

    1999-06-01

    Native fluorescence (autofluorescence) of human tissues can be a valuable source of diagnostic information for detecting premalignant and malignant lesions in the human body. Digital imaging of autofluorescence may be useful for localization of such lesions during endoscopic examinations. Tissue fluorescence of 31 adenomatous polyps obtained from 16 patients has been excited in vitro using the 325 nm line of a He-Cd laser. Digital images of the autofluorescence are recorded in six spectral bands. This study provides new data about the spatial distributions of autofluorescence intensities emitted in different spectral bands by colonic adenomatous lesions and normal colonic mucosa. Areas characterized by autofluorescence intensity lower than in normal mucosa are found for a majority of the polyps under study. The observed patterns of spatial distribution differ for the different spectral bands and for different polypoid lesions. No inverse correlation is found between the emission intensity and the thickness of colonic mucosa. The results indicate the spectral bands most useful for diagnostic applications and demonstrate the complexity of the optical processes involved in shaping both the spectra and intensities of the autofluorescence. PMID:10515079

  19. Widefield multiphoton excited fluorescence microscopy for animal study in vivo

    NASA Astrophysics Data System (ADS)

    Cheng, L.-C.; Chang, C.-Y.; Lin, C.-H.; Su, Y.-D.; Huang, T.-Y.; Chen, S.-J.

    2010-08-01

    Unlike conventional multiphoton excited microscopy according to pixel-by-pixel point scanning, a widefield multiphoton excited microscopy based on spatiotemporal focusing has been developed to construct three-dimensional (3D) multiphoton fluorescence images only with the need of an axial scanning. By implementing a 4.0 W 10 kHz femtosecond laser amplifier with an instant strong peak power and a fast TE-cooled EMCCD camera with an ultra-sensitive fluorescence detection, the multiphoton excited fluorescence images with the excitation area over 100 μm x 100 μm can be achieved at a frame rate up to 80 Hz. A mechanical shutter is utilized to control the exposure time of 1 ms, i.e. average ten laser pulses reach the fluorescent specimen, and hence an uniform enough multiphoton excited fluorescence image can be attained with less photobleaching. The Brownian motion of microbeads and 3D neuron cells of a rat cerebellum have been observed with a lateral spatial resolution of 0.24 μm and an axial resolution of 2.5 μm. Therefore, the developed widefield multiphoton microscopy can provide fast and high-resolution multiphoton excited fluorescence images for animal study in vivo.

  20. Caries imaging by teeth (auto)luminescence spectral analysis

    NASA Astrophysics Data System (ADS)

    Jonusauskas, Gediminas; Abraham, Emmanuel; Oberle, Jean; Rulliere, Claude; Peli, Jean-Francoic; Dorignac, Georges

    2003-10-01

    We propose a new technique for caries imaging by the spectral analysis of teeth luminescence excited by the near UV light. This diagnostic/control method can be applied for the all optically accessible teeth surfaces. The photo-physical studies suggest that hydroxylapatite luminescence, excited in the near UV, comes from de-excitation of crystalline structure defects in interaction with charge donating/accepting en ironment.

  1. High Speed 2D Hadamard Transform Spectral Imager

    SciTech Connect

    WEHLBURG, JOSEPH C.; WEHLBURG, CHRISTINE M.; SMITH, JODY L.; SPAHN, OLGA B.; SMITH, MARK W.; BONEY, CRAIG M.

    2003-02-01

    Hadamard Transform Spectrometer (HTS) approaches share the multiplexing advantages found in Fourier transform spectrometers. Interest in Hadamard systems has been limited due to data storage/computational limitations and the inability to perform accurate high order masking in a reasonable amount of time. Advances in digital micro-mirror array (DMA) technology have opened the door to implementing an HTS for a variety of applications including fluorescent microscope imaging and Raman imaging. A Hadamard transform spectral imager (HTSI) for remote sensing offers a variety of unique capabilities in one package such as variable spectral and temporal resolution, no moving parts (other than the micro-mirrors) and vibration tolerance. Two approaches to for 2D HTS systems have been investigated in this LDRD. The first approach involves dispersing the incident light, encoding the dispersed light then recombining the light. This method is referred to as spectral encoding. The other method encodes the incident light then disperses the encoded light. The second technique is called spatial encoding. After creating optical designs for both methods the spatial encoding method was selected as the method that would be implemented because the optical design was less costly to implement.

  2. Design and fabrication of sinusoidal spectral filters for multispectral imaging

    NASA Astrophysics Data System (ADS)

    Ni, Chuan; Jia, Jie; Hirakawa, Keigo; Sarangan, Andrew

    2015-08-01

    Multispectral imaging beyond the three RGB colors still remains a challenge, especially in portable inexpensive systems. In this paper, we describe the design and fabrication of broadband multichroic filters that have a sinusoidal transmission spectra to utilize a novel methodology based on the Fourier spectral reconstruction in the frequency domain. Since the spectral filters are posed as an optimal sampling of hyperspectral images, they also allow for the reconstruction of the full spectrum from subsequent demosaicking algorithms. Unlike conventional Color Filter Arrays (CFA) which utilizes absorption dyes embedded in a polymeric material, the sinusoidal multichroic filters require an all-dielectric interference filter design. However, the goal of most dielectric filter designs is to achieve sharp transitions with high-contrast. A smoothly varying sinusoidal transition is more difficult with conventional approaches. However, this can be achieved by trading off the contrast. Following the principles of a simple Fabry-Perot cavity, we have designed and built interference filters from 0.5 sinusoidal periods to 3 sinusoidal periods from 450nm to 900nm spectral range. Also, in order to maintain a uniform period across the entire spectrum, the material must have a very low dispersion. In this design, we have used ZnS as the cavity material. The six filters have been used in a multispectral imaging test bed.

  3. Solar abundances with the SPICE spectral imager on Solar Orbiter

    NASA Astrophysics Data System (ADS)

    Giunta, Alessandra; Haberreiter, Margit; Peter, Hardi; Vial, Jean-Claude; Harrison, Richard; Parenti, Susanna; Innes, Davina; Schmutz, Werner; Buchlin, Eric; Chamberlin, Phillip; Thompson, William; Bocchialini, Karine; Gabriel, Alan; Morris, Nigel; Caldwell, Martin; Auchere, Frederic; Curdt, Werner; Teriaca, Luca; Hassler, Donald M.; DeForest, Craig; Hansteen, Viggo; Carlsson, Mats; Philippon, Anne; Janvier, Miho; Wimmer-Schweingruber, Robert; Griffin, Douglas; Baudin, Frederic; Davila, Joseph; Fludra, Andrzej; Waltham, Nick; Eccleston, Paul; Gottwald, Alexander; Klein, Roman; Hanley, John; Walls, Buddy; Howe, Chris; Schuehle, Udo; Gyo, Manfred; Pfiffner, Dany

    2016-07-01

    Elemental composition of the solar atmosphere and in particular abundance bias of low and high First Ionization Potential (FIP) elements are a key tracer of the source regions of the solar wind. These abundances and their spatio-temporal variations, as well as the other plasma parameters , will be derived by the SPICE (Spectral Imaging of the Coronal Environment) EUV spectral imager on the upcoming Solar Orbiter mission. SPICE is designed to provide spectroheliograms (spectral images) using a core set of emission lines arising from ions of both low-FIP and high-FIP elements. These lines are formed over a wide range of temperatures, enabling the analysis of the different layers of the solar atmosphere. SPICE will use these spectroheliograms to produce dynamic composition maps of the solar atmosphere to be compared to in-situ measurements of the solar wind composition of the same elements (i.e. O, Ne, Mg, Fe). This will provide a tool to study the connectivity between the spacecraft (the Heliosphere) and the Sun. We will discuss the SPICE capabilities for such composition measurements.

  4. Single-shot ultrafast tomographic imaging by spectral multiplexing

    NASA Astrophysics Data System (ADS)

    Matlis, N. H.; Axley, A.; Leemans, W. P.

    2012-10-01

    Computed tomography has profoundly impacted science, medicine and technology by using projection measurements scanned over multiple angles to permit cross-sectional imaging of an object. The application of computed tomography to moving or dynamically varying objects, however, has been limited by the temporal resolution of the technique, which is set by the time required to complete the scan. For objects that vary on ultrafast timescales, traditional scanning methods are not an option. Here we present a non-scanning method capable of resolving structure on femtosecond timescales by using spectral multiplexing of a single laser beam to perform tomographic imaging over a continuous range of angles simultaneously. We use this technique to demonstrate the first single-shot ultrafast computed tomography reconstructions and obtain previously inaccessible structure and position information for laser-induced plasma filaments. This development enables real-time tomographic imaging for ultrafast science, and offers a potential solution to the challenging problem of imaging through scattering surfaces.

  5. Light source design for spectral tuning in biomedical imaging.

    PubMed

    Basu, Chandrajit; Schlangen, Sebastian; Meinhardt-Wollweber, Merve; Roth, Bernhard

    2015-10-01

    We propose an architecture with a remote phosphor-based modular and compact light-emitting diode (LED) light source in a noncontact dermoscope prototype for skin cancer screening. The spectrum and color temperature of the output light can easily and significantly be changed depending on spectral absorption characteristics of the tissues being imaged. The new system has several advantages compared to state-of-the-art phosphor converted ultrabright white LEDs, used in a wide range of medical imaging devices, which have a fixed spectrum and color temperature at a given operating point. In particular, the system can more easily be adapted to the requirements originating from different tissues in the human body, which have wavelength-dependent absorption and reflectivity. This leads to improved contrast for different kinds of imaged tissue components. The concept of such a lighting architecture can be vastly utilized in many other medical imaging devices including endoscopic systems. PMID:26839911

  6. In vivo multiphoton tomography of inflammatory tissue and melanoma

    NASA Astrophysics Data System (ADS)

    Riemann, Iris; Dimitrow, Enrico; Kaatz, Martin; Fluhr, Joachim; Elsner, Peter; Kobow, Jens; Konig, Karsten

    2005-04-01

    Multiphoton optical tomography provides the capability of non-invasive optical sectioning of skin with high spatial and intracellular resolution as well as high NIR (near infrared) light penetration into pigmented skin areas. The imaging system DermaInspect based on femtosecond laser pulses was used to perform multiphoton optical tomography in clinical studies. Patients with abnormal pigmented tissues were imaged in vivo. After the multiphoton imaging procedure, biopsies were taken, imaged again and further processed with standard histological methods. We report on preliminary results. The visualization of pigmented cell clusters based on non-linear luminescence using the novel multiphoton device was possible. These clusters could be clearly distinguished from non-pigmented cells. Cancerous tissues showed significant differences in the cell structure of the epidermal layers. The system DermaInspect might become a high resolution diagnostic tool for melanoma diagnostics.

  7. Biomass estimator for NIR image with a few additional spectral band images taken from light UAS

    NASA Astrophysics Data System (ADS)

    Pölönen, Ilkka; Salo, Heikki; Saari, Heikki; Kaivosoja, Jere; Pesonen, Liisa; Honkavaara, Eija

    2012-05-01

    A novel way to produce biomass estimation will offer possibilities for precision farming. Fertilizer prediction maps can be made based on accurate biomass estimation generated by a novel biomass estimator. By using this knowledge, a variable rate amount of fertilizers can be applied during the growing season. The innovation consists of light UAS, a high spatial resolution camera, and VTT's novel spectral camera. A few properly selected spectral wavelengths with NIR images and point clouds extracted by automatic image matching have been used in the estimation. The spectral wavelengths were chosen from green, red, and NIR channels.

  8. Differential Multiphoton Laser Scanning Microscopy

    PubMed Central

    Field, Jeffrey J.; Sheetz, Kraig E.; Chandler, Eric V.; Hoover, Erich E.; Young, Michael D.; Ding, Shi-you; Sylvester, Anne W.; Kleinfeld, David; Squier, Jeff A.

    2016-01-01

    Multifocal multiphoton microscopy (MMM) in the biological and medical sciences has become an important tool for obtaining high resolution images at video rates. While current implementations of MMM achieve very high frame rates, they are limited in their applicability to essentially those biological samples that exhibit little or no scattering. In this paper, we report on a method for MMM in which imaging detection is not necessary (single element point detection is implemented), and is therefore fully compatible for use in imaging through scattering media. Further, we demonstrate that this method leads to a new type of MMM wherein it is possible to simultaneously obtain multiple images and view differences in excitation parameters in a single shot. PMID:27390511

  9. Evaluation of the oxidative stress of psoriatic fibroblasts based on spectral two-photon fluorescence lifetime imaging

    NASA Astrophysics Data System (ADS)

    Kapsokalyvas, Dimitrios; Barygina, Victoria; Cicchi, Riccardo; Fiorillo, Claudia; Pavone, Francesco S.

    2013-02-01

    Psoriasis is an autoimmune disease of the skin characterized by hyperkeratosis, hyperproliferation of the epidermis, inflammatory cell accumulation and increased dilatation of dermal papillary blood vessels. Metabolic activity is increased in the epidermis and the dermis. Oxidative stress is high mainly due to reactive oxygen species (ROS) originating from the skin environment and cellular metabolism. We employed a custom multiphoton microscope coupled with a FLIM setup to image primary culture fibroblast cells from perilesional and lesional psoriatic skin in-vitro. Twophoton excited fluorescence images revealed the morphological differences between healthy and psoriatic fibroblasts. Based on the spectral analysis of the NADH and FAD components the oxidative stress was assessed and found to be higher in psoriatic cells. Furthermore the fluorescence lifetime properties were investigated with a TCSPC FLIM module. Mean fluorescence lifetime was found to be longer in psoriatic lesional cells. Analysis of the fast (τ1) and slow (τ2) decay lifetimes revealed a decrease of the ratio of the contribution of the fast (α1) parameter to the contribution of the slow (α2) parameter. The fluorescence in the examined part of the spectrum is attributed mainly to NADH. The decrease of the ratio (α1)/ (α2) is believed to correlate strongly with the anti-oxidant properties of NADH which can lead to the variation of its population in high ROS environment. This methodology could serve as an index of the oxidative status in cells and furthermore could be used to probe the oxidative stress of tissues in-vivo.

  10. Interactive transmission of spectrally wavelet-transformed hyperspectral images

    NASA Astrophysics Data System (ADS)

    Monteagudo-Pereira, José Lino; Bartrina-Rapesta, Joan; Aulí-Llinàs, Francesc; Serra-Sagristà, Joan; Zabala, Alaitz; Pons, Xavier

    2008-08-01

    The size of images used in remote sensing scenarios has constantly increased in the last years. Remote sensing images are not only stored, but also processed and transmitted, raising the need for more resources and bandwidth. On another side, hyperspectral remote sensing images have a large number of components with a significant inter-component redundancy, which is usually taken into account by many image coding systems to improve the coding performance. The main approaches used to decorrelate the spectral dimension are the Karhunen Loeve-Transform and the Discrete Wavelet Transform (DWT). This paper is focused on DWT decorrelators because they have a lower computational complexity, and because they provide interesting features such as component and resolution scalability and progressive transmission. Influence of the spectral transform is investigated, considering the DWT kernel applied and the number of decomposition levels. In addition, a JPIP compliant application, CADI, is introduced. It may be useful to test new protocols, techniques, or coding systems, without requiring significant changes on the application. CADI can be run in most computer platforms and devices thanks to the use of JAVA and the configuration of a light-version, suitable for devices with constrained resources.

  11. Localization of methane distributions by spectrally tuned infrared imaging

    NASA Astrophysics Data System (ADS)

    Gross, Werner; Hierl, Thomas; Scheuerpflug, H.; Schirl, U.; Schreer, Oliver; Schulz, Max J.

    1999-01-01

    We present a novel method, the Gas Imaging (GIm) method, developed for the localization of gas distributions in the atmosphere. The method is suitable for the detection of a gases which exhibit at least one absorption line in the IR spectral range. In this paper the GIm method is demonstrated for methane released into the atmosphere from leaks along natural gas pipelines. Methane distributions in the atmosphere around the leaky pipeline are detected and visualized by spectrally tuned IR imaging. In contrast to conventional techniques which utilize laser radiation sources or scanning, we irradiate the overall region under investigation by 1 kW halogen lamps. The scene background is subtracted by a real-time computer evaluation of the image. The methane gas emitted from the leak creates a flickering cloud in the image which is easily recognized. Methane concentrations as low as 0.03 percent by volume are visible. The method was successfully tested under realistic conditions on a buried pipeline by a natural gas provider.

  12. Thermal Infrared Spectral Imager for Airborne Science Applications

    NASA Technical Reports Server (NTRS)

    Johnson, William R.; Hook, Simon J.; Mouroulis, Pantazis; Wilson, Daniel W.; Gunapala, Sarath D.; Hill, Cory J.; Mumolo, Jason M.; Eng, Bjorn T.

    2009-01-01

    An airborne thermal hyperspectral imager is under development which utilizes the compact Dyson optical configuration and quantum well infrared photo detector (QWIP) focal plane array. The Dyson configuration uses a single monolithic prism-like grating design which allows for a high throughput instrument (F/1.6) with minimal ghosting, stray-light and large swath width. The configuration has the potential to be the optimal imaging spectroscopy solution for lighter-than-air (LTA) vehicles and unmanned aerial vehicles (UAV) due to its small form factor and relatively low power requirements. The planned instrument specifications are discussed as well as design trade-offs. Calibration testing results (noise equivalent temperature difference, spectral linearity and spectral bandwidth) and laboratory emissivity plots from samples are shown using an operational testbed unit which has similar specifications as the final airborne system. Field testing of the testbed unit was performed to acquire plots of apparent emissivity for various known standard minerals (such as quartz). A comparison is made using data from the ASTER spectral library.

  13. Multiphoton microscopy and microspectroscopy for diagnostics of inflammatory and neoplastic lung

    NASA Astrophysics Data System (ADS)

    Pavlova, Ina; Hume, Kelly R.; Yazinski, Stephanie A.; Flanders, James; Southard, Teresa L.; Weiss, Robert S.; Webb, Watt W.

    2012-03-01

    Limitations of current medical procedures for detecting early lung cancers inspire the need for new diagnostic imaging modalities for the direct microscopic visualization of lung nodules. Multiphoton microscopy (MPM) provides for subcellular resolution imaging of intrinsic fluorescence from unprocessed tissue with minimal optical attenuation and photodamage. We demonstrate that MPM detects morphological and spectral features of lung tissue and differentiates between normal, inflammatory and neoplastic lung. Ex vivo MPM imaging of intrinsic two-photon excited fluorescence was performed on mouse and canine neoplastic, inflammatory and tumor-free lung sites. Results showed that MPM detected microanatomical differences between tumor-free and neoplastic lung tissue similar to standard histopathology but without the need for tissue processing. Furthermore, inflammatory sites displayed a distinct red-shifted fluorescence compared to neoplasms in both mouse and canine lung, and adenocarcinomas displayed a less pronounced fluorescence emission in the 500 to 550 nm region compared to adenomas in mouse models of lung cancer. These spectral distinctions were also confirmed by two-photon excited fluorescence microspectroscopy. We demonstrate the feasibility of applying MPM imaging of intrinsic fluorescence for the differentiation of lung neoplasms, inflammatory and tumor-free lung, which motivates the application of multiphoton endoscopy for the in situ imaging of lung nodules.

  14. Clinical multiphoton endoscopy with FLIM capability

    NASA Astrophysics Data System (ADS)

    Weinigel, Martin; Breunig, Hans Georg; Fischer, Peter; Kellner-Höfer, Marcel; Bückle, Rainer; König, Karsten

    2013-02-01

    Multiphoton endoscopy can be applied for intra-corporeal imaging as well as to examine otherwise hard-to-access tissue areas like chronic wounds. Using high-NA (NA = 0.8) gradient-index (GRIN) lens-based endoscopes with a diameter of 1.4 mm and effective lengths of 7 mm and 20 mm, respectively, two-photon excitation of endogenous fluorophores and second-harmonic generation (SHG) is used for multimodal in vivo imaging of human skin. A further imaging modality is fluorescence lifetime imaging (FLIM) which allows functional imaging to investigate the healing mechanism of chronic wounds and the corresponding cell metabolism. We performed first in vivo measurements using FLIM endoscopy with the medically-certified multiphoton tomograph MPTflex® in combination with a computer-controlled motorized scan head and a GRIN-lens endoscope.

  15. An Integrated Imaging Detector of Polarization and Spectral Content

    NASA Technical Reports Server (NTRS)

    Rust, D. M.; Thompson, K. E.

    1993-01-01

    A new type of image detector has been designed to simultaneously analyze the polarization of light at all picture elements in a scene. The Integrated Dual Imaging Detector (IDID) consists of a polarizing beamsplitter bonded to a charge-coupled device (CCD), with signal-analysis circuitry and analog-to-digital converters, all integrated on a silicon chip. It should be capable of 1:10(exp 4) polarization discrimination. The IDID should simplify the design and operation of imaging polarimeters and spectroscopic imagers used, for example, in atmospheric and solar research. Innovations in the IDID include (1) two interleaved 512 x 1024-pixel imaging arrays (one for each polarization plane); (2) large dynamic range (well depth of 10(exp 6) electrons per pixel); (3) simultaneous readout of both images at 10 million pixels per second each; (4) on-chip analog signal processing to produce polarization maps in real time; (5) on-chip 10-bit A/D conversion. When used with a lithium-niobate Fabry-Perot etalon or other color filter that can encode spectral information as polarization, the IDID can collect and analyze simultaneous images at two wavelengths. Precise photometric analysis of molecular or atomic concentrations in the atmosphere is one suggested application. When used in a solar telescope, the IDID will charge the polarization, which can then be converted to maps of the vector magnetic fields on the solar surface.

  16. Computed tomography based spectral imaging for fluorescence microscopy

    NASA Astrophysics Data System (ADS)

    Ford, Bridget Kathleen

    Multispectral imaging has been used for decades in remote sensing to enhance the classification, discrimination and characterization of materials. Only recently has this same technology been similarly applied to fixed biological samples in cytogenetics, pathology and medicine. A further extension to in vivo studies is often limited by the low levels of associated fluorescence as well as the increased temporal resolution required to analyze physiological changes. In addition, the cellular response to a specific agonist is often heterogeneous across the cellular field requiring a combination of sufficient spatial and temporal resolutions. A computed tomography imaging spectrometer (CTIS) has been developed which overcomes these limitations by simultaneously collecting extended range spectral information (470--740 nm, 5 nm sampling) across a 2-D field of view (200 mum x 200 mum, 0.96 mum sampling). The CTIS uses a computer generated hologram to produce a 5 x 5 array of images with differing amounts and directions of dispersion. This set of images allows the 3-D signal (x, y, lambda) from a fluorescent sample to be mapped onto a 2-D detector array. In this way, the full spectral and spatial information is acquired for a 2-D cellular field during a single integration time (presently 2 sec for biological specimens). The CTIS's design, calibration, and underlying theory are described in detail. In addition, the capability of the CTIS to simultaneously collect the fluorescence emission of multiple fluorophores across a 2-D cellular field is demonstrated. Specifically, the combined spectral variations of seminapthorhodafluor-I and enhanced green fluorescent protein were followed in rat insulinoma cells in order to extend the linear range of intracellular pH detection.

  17. Detection and mapping of trace explosives on surfaces under ambient conditions using multiphoton electron extraction spectroscopy (MEES).

    PubMed

    Tang, Shisong; Vinerot, Nataly; Fisher, Danny; Bulatov, Valery; Yavetz-Chen, Yehuda; Schechter, Israel

    2016-08-01

    Multiphoton electron extraction spectroscopy (MEES) is an analytical method in which UV laser pulses are utilized for extracting electrons from solid surfaces in multiphoton processes under ambient conditions. Counting the emitted electrons as a function of laser wavelength results in detailed spectral features, which can be used for material identification. The method has been applied to detection of trace explosives on a variety of surfaces. Detection was possible on dusty swabs spiked with explosives and also in the standard dry-transfer contamination procedure. Plastic explosives could also be detected. The analytical limits of detection (LODs) are in the sub pmole range, which indicates that MEES is one of the most sensitive detection methods for solid surface under ambient conditions. Scanning the surface with the laser allows for its imaging, such that explosives (as well as other materials) can be located. The imaging mode is also useful in forensic applications, such as detection of explosives in human fingerprints. PMID:27216679

  18. Modeling and image reconstruction in spectrally resolved bioluminescence tomography

    NASA Astrophysics Data System (ADS)

    Dehghani, Hamid; Pogue, Brian W.; Davis, Scott C.; Patterson, Michael S.

    2007-02-01

    Recent interest in modeling and reconstruction algorithms for Bioluminescence Tomography (BLT) has increased and led to the general consensus that non-spectrally resolved intensity-based BLT results in a non-unique problem. However, the light emitted from, for example firefly Luciferase, is widely distributed over the band of wavelengths from 500 nm to 650 nm and above, with the dominant fraction emitted from tissue being above 550 nm. This paper demonstrates the development of an algorithm used for multi-wavelength 3D spectrally resolved BLT image reconstruction in a mouse model. It is shown that using a single view data, bioluminescence sources of up to 15 mm deep can be successfully recovered given correct information about the underlying tissue absorption and scatter.

  19. Measuring Agarwood Formation Ratio Quantitatively by Fluorescence Spectral Imaging Technique.

    PubMed

    Huang, Botao; Nguyen, Duykien; Liu, Tianyi; Jiang, Kaibin; Tan, Jinfen; Liu, Chunxin; Zhao, Jing; Huang, Shaowei

    2015-01-01

    Agarwood is a kind of important and precious traditional Chinese medicine. With the decreasing of natural agarwood, artificial cultivation has become more and more important in recent years. Quantifying the formation of agarwood is an essential work which could provide information for guiding cultivation and controlling quality. But people only can judge the amount of agarwood qualitatively by experience before. Fluorescence multispectral imaging method is presented to measure the agarwood quantitatively in this paper. A spectral cube from 450 nm to 800 nm was captured under the 365 nm excitation sources. The nonagarwood, agarwood, and rotten wood in the same sample were distinguished based on analyzing the spectral cube. Then the area ratio of agarwood to the whole sample was worked out, which is the quantitative information of agarwood area percentage. To our knowledge, this is the first time that the formation of agarwood was quantified accurately and nondestructively. PMID:26089935

  20. Hindlimb heating increases vascular access of large molecules to murine tibial growth plates measured by in vivo multiphoton imaging

    PubMed Central

    Efaw, Morgan L.; Williams, Rebecca M.

    2013-01-01

    Advances in understanding the molecular regulation of longitudinal growth have led to development of novel drug therapies for growth plate disorders. Despite progress, a major unmet challenge is delivering therapeutic agents to avascular-cartilage plates. Dense extracellular matrix and lack of penetrating blood vessels create a semipermeable “barrier,” which hinders molecular transport at the vascular-cartilage interface. To overcome this obstacle, we used a hindlimb heating model to manipulate bone circulation in 5-wk-old female mice (n = 22). Temperatures represented a physiological range of normal human knee joints. We used in vivo multiphoton microscopy to quantify temperature-enhanced delivery of large molecules into tibial growth plates. We tested the hypothesis that increasing hindlimb temperature from 22°C to 34°C increases vascular access of large systemic molecules, modeled using 10, 40, and 70 kDa dextrans that approximate sizes of physiological regulators. Vascular access was quantified by vessel diameter, velocity, and dextran leakage from subperichondrial plexus vessels and accumulation in growth plate cartilage. Growth plate entry of 10 kDa dextrans increased >150% at 34°C. Entry of 40 and 70 kDa dextrans increased <50%, suggesting a size-dependent temperature enhancement. Total dextran levels in the plexus increased at 34°C, but relative leakage out of vessels was not temperature dependent. Blood velocity and vessel diameter increased 118% and 31%, respectively, at 34°C. These results demonstrate that heat enhances vascular carrying capacity and bioavailability of large molecules around growth plates, suggesting that temperature could be a noninvasive strategy for modulating delivery of therapeutics to impaired growth plates of children. PMID:24371019

  1. Gastric Cancer Staging with Dual Energy Spectral CT Imaging

    PubMed Central

    Pan, Zilai; Pang, Lifang; Ding, Bei; Yan, Chao; Zhang, Huan; Du, Lianjun; Wang, Baisong; Song, Qi; Chen, Kemin; Yan, Fuhua

    2013-01-01

    Purpose To evaluate the clinical utility of dual energy spectral CT (DEsCT) in staging and characterizing gastric cancers. Materials and Methods 96 patients suspected of gastric cancers underwent dual-phasic scans (arterial phase (AP) and portal venous phase (PP)) with DEsCT mode. Three types of images were reconstructed for analysis: conventional polychromatic images, material-decomposition images, and monochromatic image sets with photon energies from 40 to 140 keV. The polychromatic and monochromatic images were compared in TNM staging. The iodine concentrations in the lesions and lymph nodes were measured on the iodine-based material-decomposition images. These values were further normalized against that in aorta and the normalized iodine concentration (nIC) values were statistically compared. Results were correlated with pathological findings. Results The overall accuracies for T, N and M staging were (81.2%, 80.0%, and 98.9%) and (73.9%, 75.0%, and 98.9%) determined with the monochromatic images and the conventional kVp images, respectively. The improvement of the accuracy in N-staging using the keV images was statistically significant (p<0.05). The nIC values between the differentiated and undifferentiated carcinoma and between metastatic and non-metastatic lymph nodes were significantly different both in AP (p = 0.02, respectively) and PP (p = 0.01, respectively). Among metastatic lymph nodes, nIC of the signet-ring cell carcinoma were significantly different from the adenocarcinoma (p = 0.02) and mucinous adenocarcinoma (p = 0.01) in PP. Conclusion The monochromatic images obtained with DEsCT may be used to improve the N-staging accuracy. Quantitative iodine concentration measurements may be helpful for differentiating between differentiated and undifferentiated gastric carcinoma, and between metastatic and non-metastatic lymph nodes. PMID:23424614

  2. In vivo simultaneous multispectral fluorescence imaging with spectral multiplexed volume holographic imaging system

    NASA Astrophysics Data System (ADS)

    Lv, Yanlu; Zhang, Jiulou; Zhang, Dong; Cai, Wenjuan; Chen, Nanguang; Luo, Jianwen

    2016-06-01

    A simultaneous multispectral fluorescence imaging system incorporating multiplexed volume holographic grating (VHG) is developed to acquire multispectral images of an object in one shot. With the multiplexed VHG, the imaging system can provide the distribution and spectral characteristics of multiple fluorophores in the scene. The implementation and performance of the simultaneous multispectral imaging system are presented. Further, the system's capability in simultaneously obtaining multispectral fluorescence measurements is demonstrated with in vivo experiments on a mouse. The demonstrated imaging system has the potential to obtain multispectral images fluorescence simultaneously.

  3. Multiphoton-Excited Serotonin Photochemistry

    PubMed Central

    Gostkowski, Michael L.; Allen, Richard; Plenert, Matthew L.; Okerberg, Eric; Gordon, Mary Jane; Shear, Jason B.

    2004-01-01

    We report photochemical and photophysical studies of a multiphoton-excited reaction of serotonin that previously has been shown to generate a photoproduct capable of emitting broadly in the visible spectral region. The current studies demonstrate that absorption of near-infrared light by an intermediate state prepared via three-photon absorption enhances the photoproduct formation yield, with the largest action cross sections (∼10−19 cm2) observed at the short-wavelength limit of the titanium:sapphire excitation source. The intermediate state is shown to persist for at least tens of nanoseconds and likely to be different from a previously reported oxygen-sensitive intermediate. In addition, the two-photon fluorescence action spectrum for the fluorescent photoproduct was determined and found to have a maximum at ∼780 nm (3.2 eV). A general mechanism for this photochemical process is proposed. PMID:15111435

  4. Dual-order snapshot spectral imaging of plasmonic nanoparticles

    NASA Astrophysics Data System (ADS)

    Nusz, Gregory J.; Marinakos, Stella M.; Rangarajan, Srinath; Chilkoti, Ashutosh

    2011-07-01

    The development of truly scalable, multiplexed optical microarrays requires a detection platform capable of simultaneous detection of multiple signals in real-time. We present a technique we term dual-order snapshot spectroscopic imaging (DOSSI) and demonstrate that it can be effectively used to collect spectrally resolved images of a full field of view of sparsely located spots in real time. Resonant peaks of plasmonic gold nanoparticles were tracked as a function of their surrounding refractive index. Measurement uncertainty analysis indicated that the spectral resolution of DOSSI in the described configuration is approximately 0.95nm. Further, real-time measurements by DOSSI allowed discrimination between optically identical nanoparticles that were functionalized with two homologous small molecule ligands that bound to the same protein, albeit with different affinity, based purely on their different molecular interaction kinetics---a feat not possible with slower raster-type hyperspectral imaging systems, or other dark-field optical detection systems that solely rely on end point measurements. Kinetic measurements of plasmon bands by DOSSI can be performed with a relatively simple optical system, thereby opening up the possibility of developing low-cost detectors for arrayed plasmonic diagnostics.

  5. Block-based reconstructions for compressive spectral imaging

    NASA Astrophysics Data System (ADS)

    Correa, Claudia V.; Arguello, Henry; Arce, Gonzalo R.

    2013-05-01

    Coded Aperture Snapshot Spectral Imaging system (CASSI) captures spectral information of a scene using a reduced amount of focal plane array (FPA) projections. These projections are highly structured and localized such that each measurement contains information of a small portion of the data cube. Compressed sensing reconstruction algorithms are then used to recover the underlying 3-dimensional (3D) scene. The computational burden to recover a hyperspectral scene in CASSI is overwhelming for some applications such that reconstructions can take hours in desktop architectures. This paper presents a new method to reconstruct a hyperspectral signal from its compressive measurements using several overlapped block reconstructions. This approach exploits the structure of the CASSI sensing matrix to separately reconstruct overlapped regions of the 3D scene. The resultant reconstructions are then assembled to obtain the full recovered data cube. Typically, block-processing causes undesired artifacts in the recovered signal. Vertical and horizontal overlaps between adjacent blocks are then used to avoid these artifacts and increase the quality of reconstructed images. The reconstruction time and the quality of the reconstructed images are calculated as a function of the block-size and the amount of overlapped regions. Simulations show that the quality of the reconstructions is increased up to 6 dB and the reconstruction time is reduced up to 4 times when using block-based reconstruction instead of full data cube recovery at once. The proposed method is suitable for multi-processor architectures in which each core recovers one block at a time.

  6. Dual Order Snapshot Spectral Imaging of Plasmonic Nanoparticles

    PubMed Central

    Nusz, Gregory J.; Marinakos, Stella M.; Rangarajan, Srinath; Chilkoti, Ashutosh

    2013-01-01

    The development of truly scalable, multiplexed optical microarrays requires a detection platform capable of simultaneous detection of multiple independent signals in real-time. We present a technique we term dual order snapshot spectroscopic imaging (DOSSI) and demonstrate that it can be effectively used to collect spectrally-resolved images of a full field of view of sparsely located spots in real-time. Resonant peaks of plasmonic gold nanoparticles were tracked as a function of their surrounding refractive index. Measurement uncertainty analysis indicated that the spectral resolution of DOSSI in the described configuration is approximately 0.95 nm. Further, real-time measurements by DOSSI allowed discrimination between optically identical nanoparticles that were functionalized with two homologous small molecule ligands that bound to the same protein, albeit with different affinity, based purely on their different molecular interaction kinetics– a feat not possible with slower raster-type hyperspectral imaging systems, or other darkfield optical detection systems that solely rely on end-point measurements. Kinetic measurements of plasmon bands by DOSSI can be performed with a relatively simple optical system, thereby opening up the possibility of developing low-cost detectors for arrayed plasmonic diagnostics. PMID:21772408

  7. CHOROIDAL IMAGING USING SPECTRAL-DOMAIN OPTICAL COHERENCE TOMOGRAPHY

    PubMed Central

    Regatieri, Caio V.; Branchini, Lauren; Fujimoto, James G.; Duker, Jay S.

    2012-01-01

    Background A structurally and functionally normal choroidal vasculature is essential for retinal function. Therefore, a precise clinical understanding of choroidal morphology should be important for understanding many retinal and choroidal diseases. Methods PUBMED (http://www.ncbi.nlm.nih.gov/sites/entrez?db=pubmed) was used for most of the literature search for this article. The criterion for inclusion of an article in the references for this review was that it included materials about both the clinical and the basic properties of choroidal imaging using spectral-domain optical coherence tomography. Results Recent reports show successful examination and accurate measurement of choroidal thickness in normal and pathologic states using spectral-domain optical coherence tomography systems. This review focuses on the principles of the new technology that make choroidal imaging using optical coherence tomography possible and on the changes that subsequently have been documented to occur in the choroid in various diseases. Additionally, it outlines future directions in choroidal imaging. Conclusion Optical coherence tomography is now proven to be an effective noninvasive tool to evaluate the choroid and to detect choroidal changes in pathologic states. Additionally, choroidal evaluation using optical coherence tomography can be used as a parameter for diagnosis and follow-up. PMID:22487582

  8. Ultrahigh speed spectral/Fourier domain ophthalmic OCT imaging

    NASA Astrophysics Data System (ADS)

    Potsaid, Benjamin; Gorczynska, Iwona; Srinivasan, Vivek J.; Chen, Yueli; Liu, Jonathan; Jiang, James; Cable, Alex; Duker, Jay S.; Fujimoto, James G.

    2009-02-01

    Ultrahigh speed spectral / Fourier domain optical coherence tomography (OCT) imaging using a CMOS line scan camera with acquisition rates of 70,000 - 312,500 axial scans per second is investigated. Several design configurations are presented to illustrate trade-offs between acquisition speed, sensitivity, resolution and sensitivity roll-off performance. We demonstrate: extended imaging range and improved sensitivity roll-off at 70,000 axial scans per second , high speed and ultrahigh resolution imaging at 106,382 axial scans per second, and ultrahigh speed imaging at 250,000-312,500 axial scans per second. Each configuration is characterized through optical testing and the trade-offs demonstrated with in vivo imaging of the fovea and optic disk in the human retina. OCT fundus images constructed from 3D-OCT data acquired at 250,000 axial scans per second have no noticeable discontinuity of retinal features and show that there are minimal motion artifacts. The fine structures of the lamina cribrosa can be seen. Long cross sectional scans are acquired at 70,000 axial scans per second for imaging large areas of the retina, including the fovea and optic disk. Rapid repeated imaging of a small volume (4D-OCT) enables time resolved visualization of the capillary network surrounding the INL and may show individual red blood cells. The results of this study suggest that high speed CMOS cameras can achieve a significant improvement in performance for ophthalmic imaging. This promises to have a powerful impact in clinical applications by improving early diagnosis, reproducibility of measurements and enabling more sensitive assessment of disease progression or response to therapy.

  9. Spectral imaging characterization of MOEM tunable Fabry-Perot filter

    NASA Astrophysics Data System (ADS)

    Gupta, Neelam

    2012-03-01

    A miniature MOEM tunable Fabry-Perot (FP) filter development program to fabricate filters operating over spectral regions from the visible to the longwave infrared has recently succeeded in fabricating filters operating over visible/near infrared wavelength region from 400 to 800 nm. The main objective of this program is to design miniature hyperspectral imagers by placing such a miniature tunable FP filter in front of a commercial focal plane array with a suitable optical train. This novel MOEM filter design is based on using two semitransparent 30-nm thick silver-film mirrors-one fixed and one moving with application of an electrostatic force. The silver films were grown on low-cost thin commercial quartz wafers with low total thickness variation. The moving mirror is held in place by three leaf spring arm structures which were fabricated by wet etching of the quartz substrate. The size of the MOEM device is 18×24 mm2. The tunable FP filter has a 6-mm optical aperture. The fixed part has three electrodes to apply voltages and the moving mirror is used as a ground electrode. Au bumps were deposited in both parts in order to control the initial air gap distance and an Au-Au bonding was used to bond the two parts together. The electrostatic actuation changes the spacing between the two mirrors which changes the transmitted wavelength. The spectral imaging performance of MOEM filter was characterized using a tunable source and a CCD camera with suitable optics. This paper describes the MOEM filter, its characteristics and present spectral imaging characterization experiment and results.

  10. In vivo non-invasive multiphoton tomography of human skin

    NASA Astrophysics Data System (ADS)

    König, Karsten; Riemann, Iris; Ehlers, Alexander; Le Harzic, Ronan

    2005-10-01

    High resolution non-invasive 3D imaging devices are required to detect pathogenic microorganisms such as Anthrax spores, bacteria, viruses, fungi and chemical agents entering biological tissues such as the epidermis. Due to the low light penetration depth and the biodamage potential, ultraviolet light sources can not be employed to realize intratissue imaging of bio- and chemohazards. We report on the novel near infrared laser technology multiphoton tomography and the high resolution 4D imaging tool DermaInspect for non-invasive detection of intratissue agents and their influence on cellular metabolism based on multiphoton autofluorescence imaging (MAI) and second harmonic generation (SHG). Femtosecond laser pulses in the spectral range of 750 nm to 850 nm have been used to image in vivo human skin with subcellular spatial and picosecond temporal resolution. The non-linear induced autofluorescence of both, skin tissues and microorganisms, originates mainly from naturally endogenous fluorophores/protein structures like NAD(P)H, flavins, keratin, collagen, elastin, porphyrins and melanin. Bacteria emit in the blue/green spectral range due to NAD(P)H and flavoproteins and, in certain cases, in the red spectral range due to the biosynthesis of Zn-porphyrins, coproporphyrin and protoporphyrin. Collagen and exogenous non-centrosymmetric molecules can be detected by SHG signals. The system DermaInspect consists of a wavelength-tunable compact 80/90 MHz Ti:sapphire laser, a scan module with galvo scan mirrors, piezo-driven objective, fast photon detector and time-resolved single photon counting unit. It can be used to perform optical sectioning and 3D autofluorescence lifetime imaging (τ-mapping) with 1 μm spatial resolution and 270 ps temporal resolution. The parameter fluorescence lifetime depends on the type of fluorophore and its microenvironment and can be used to distinguish bio- and chemohazards from cellular background and to gain information for pathogen

  11. Multiphoton Microscopy for Visualizing Lipids in Tissue.

    PubMed

    Lee, Martin; Serrels, Alan

    2016-01-01

    Visualizing the appearance of fat droplets and adipocytes in tissue can be realized using a label-free imaging method known as coherent anti-Stokes Raman spectroscopy (CARS). CARS is a nonlinear optical technique that allows label-free imaging of a material with contrast based on the same vibrational signatures of molecules found in Raman spectroscopy. CARS can be combined with other single and multiphoton imaging modes such as second harmonic generation and two-photon fluorescence to image a broad variety of biological structures.Here we describe the construction of a multiphoton microscope that will enable the study of both fluorescently labeled and unlabeled tissue. This has been used to monitor the contribution of Wt1 expressing cells towards the visceral fat depots during gestation. PMID:27417963

  12. Spectral-overlap approach to multiframe superresolution image reconstruction.

    PubMed

    Cohen, Edward; Picard, Richard H; Crabtree, Peter N

    2016-05-20

    Various techniques and algorithms have been developed to improve the resolution of sensor-aliased imagery captured with multiple subpixel-displaced frames on an undersampled pixelated image plane. These dealiasing algorithms are typically known as multiframe superresolution (SR), or geometric SR to emphasize the role of the focal-plane array. Multiple low-resolution (LR) aliased frames of the same scene are captured and allocated to a common high-resolution (HR) reconstruction grid, leading to the possibility of an alias-free reconstruction, as long as the HR sampling rate is above the Nyquist rate. Allocating LR-frame irradiances to HR frames requires the use of appropriate weights. Here we present a novel approach in the spectral domain to calculating exactly weights based on spatial overlap areas, which we call the spectral-overlap (SO) method. We emphasize that the SO method is not a spectral approach but rather an approach to calculating spatial weights that uses spectral decompositions to exploit the array properties of the HR and LR pixels. The method is capable of dealing with arbitrary aliasing factors and interframe motions consisting of in-plane translations and rotations. We calculate example reconstructed HR images (the inverse problem) from synthetic aliased images for integer and for fractional aliasing factors. We show the utility of the SO-generated overlap-area weights in both noniterative and iterative reconstructions with known or unknown aliasing factor. We show how the overlap weights can be used to generate the Green's function (pixel response function) for noniterative dealiasing. In addition, we show how the overlap-area weights can be used to generate synthetic aliased images (the forward problem). We compare the SO approach to the spatial-domain geometric approach of O'Rourke and find virtually identical high accuracy but with significant enhancements in speed for SO. We also compare the SO weights to interpolated weights and find that

  13. A GIHS-based spectral preservation fusion method for remote sensing images using edge restored spectral modulation

    NASA Astrophysics Data System (ADS)

    Zhou, Xiran; Liu, Jun; Liu, Shuguang; Cao, Lei; Zhou, Qiming; Huang, Huawen

    2014-02-01

    High spatial resolution and spectral fidelity are basic standards for evaluating an image fusion algorithm. Numerous fusion methods for remote sensing images have been developed. Some of these methods are based on the intensity-hue-saturation (IHS) transform and the generalized IHS (GIHS), which may cause serious spectral distortion. Spectral distortion in the GIHS is proven to result from changes in saturation during fusion. Therefore, reducing such changes can achieve high spectral fidelity. A GIHS-based spectral preservation fusion method that can theoretically reduce spectral distortion is proposed in this study. The proposed algorithm consists of two steps. The first step is spectral modulation (SM), which uses the Gaussian function to extract spatial details and conduct SM of multispectral (MS) images. This method yields a desirable visual effect without requiring histogram matching between the panchromatic image and the intensity of the MS image. The second step uses the Gaussian convolution function to restore lost edge details during SM. The proposed method is proven effective and shown to provide better results compared with other GIHS-based methods.

  14. Spatial super-resolution in code aperture spectral imaging

    NASA Astrophysics Data System (ADS)

    Arguello, Henry; Rueda, Hoover F.; Arce, Gonzalo R.

    2012-06-01

    The Code Aperture Snapshot Spectral Imaging system (CASSI) senses the spectral information of a scene using the underlying concepts of compressive sensing (CS). The random projections in CASSI are localized such that each measurement contains spectral information only from a small spatial region of the data cube. The goal of this paper is to translate high-resolution hyperspectral scenes into compressed signals measured by a low-resolution detector. Spatial super-resolution is attained as an inverse problem from a set of low-resolution coded measurements. The proposed system not only offers significant savings in size, weight and power, but also in cost as low resolution detectors can be used. The proposed system can be efficiently exploited in the IR region where the cost of detectors increases rapidly with resolution. The simulations of the proposed system show an improvement of up to 4 dB in PSNR. Results also show that the PSNR of the reconstructed data cubes approach the PSNR of the reconstructed data cubes attained with high-resolution detectors, at the cost of using additional measurements.

  15. Spectral-Spatial Classification of Hyperspectral Images Using Hierarchical Optimization

    NASA Technical Reports Server (NTRS)

    Tarabalka, Yuliya; Tilton, James C.

    2011-01-01

    A new spectral-spatial method for hyperspectral data classification is proposed. For a given hyperspectral image, probabilistic pixelwise classification is first applied. Then, hierarchical step-wise optimization algorithm is performed, by iteratively merging neighboring regions with the smallest Dissimilarity Criterion (DC) and recomputing class labels for new regions. The DC is computed by comparing region mean vectors, class labels and a number of pixels in the two regions under consideration. The algorithm is converged when all the pixels get involved in the region merging procedure. Experimental results are presented on two remote sensing hyperspectral images acquired by the AVIRIS and ROSIS sensors. The proposed approach improves classification accuracies and provides maps with more homogeneous regions, when compared to previously proposed classification techniques.

  16. Imaging of blood cells based on snapshot Hyper-Spectral Imaging systems

    NASA Astrophysics Data System (ADS)

    Robison, Christopher J.; Kolanko, Christopher; Bourlai, Thirimachos; Dawson, Jeremy M.

    2015-05-01

    Snapshot Hyper-Spectral imaging systems are capable of capturing several spectral bands simultaneously, offering coregistered images of a target. With appropriate optics, these systems are potentially able to image blood cells in vivo as they flow through a vessel, eliminating the need for a blood draw and sample staining. Our group has evaluated the capability of a commercial Snapshot Hyper-Spectral imaging system, the Arrow system from Rebellion Photonics, in differentiating between white and red blood cells on unstained blood smear slides. We evaluated the imaging capabilities of this hyperspectral camera; attached to a microscope at varying objective powers and illumination intensity. Hyperspectral data consisting of 25, 443x313 hyperspectral bands with ~3nm spacing were captured over the range of 419 to 494nm. Open-source hyper-spectral data cube analysis tools, used primarily in Geographic Information Systems (GIS) applications, indicate that white blood cells features are most prominent in the 428-442nm band for blood samples viewed under 20x and 50x magnification over a varying range of illumination intensities. These images could potentially be used in subsequent automated white blood cell segmentation and counting algorithms for performing in vivo white blood cell counting.

  17. Spectral photoplethysmographic imaging sensor fusion for enhanced heart rate detection

    NASA Astrophysics Data System (ADS)

    Amelard, Robert; Clausi, David A.; Wong, Alexander

    2016-03-01

    Continuous heart rate monitoring can provide important context for quantitative clinical assessment in scenarios such as long-term health monitoring and disability prevention. Photoplethysmographic imaging (PPGI) systems are particularly useful for such monitoring scenarios as contact-based devices pose problems related to comfort and mobility. Each pixel can be regarded as a virtual PPG sensor, thus enabling simultaneous measurements of multiple skin sites. Existing PPGI systems analyze temporal PPGI sensor uctuations related to hemodynamic pulsations across a region of interest to extract the blood pulse signal. However, due to spatially varying optical properties of the skin, the blood pulse signal may not be consistent across all PPGI sensors, leading to inaccurate heart rate monitoring. To increase the hemodynamic signal-to-noise ratio (SNR), we propose a novel spectral PPGI sensor fusion method for enhanced estimation of the true blood pulse signal. Motivated by the observation that PPGI sensors with high hemodynamic SNR exhibit a spectral energy peak at the heart rate frequency, an entropy-based fusion model was formulated to combine PPGI sensors based on the sensors' spectral energy distribution. The optical PPGI device comprised a near infrared (NIR) sensitive camera and an 850 nm LED. Spatially uniform irradiance was achieved by placing optical elements along the LED beam, providing consistent illumination across the skin area. Dual-mode temporally coded illumination was used to negate the temporal effect of ambient illumination. Experimental results show that the spectrally weighted PPGI method can accurately and consistently extract heart rate information where traditional region-based averaging fails.

  18. Feasibility study of a novel miniaturized spectral imaging system architecture in UAV surveillance

    NASA Astrophysics Data System (ADS)

    Liu, Shuyang; Zhou, Tao; Jia, Xiaodong; Cui, Hushan; Huang, Chengjun

    2016-01-01

    The spectral imaging technology is able to analysis the spectral and spatial geometric character of the target at the same time. To break through the limitation brought by the size, weight and cost of the traditional spectral imaging instrument, a miniaturized novel spectral imaging based on CMOS processing has been introduced in the market. This technology has enabled the possibility of applying spectral imaging in the UAV platform. In this paper, the relevant technology and the related possible applications have been presented to implement a quick, flexible and more detailed remote sensing system.

  19. Imaging spectral electrical properties of variably saturated porous media

    NASA Astrophysics Data System (ADS)

    Kelter, Matthias; Huisman, Johann A.; Kemna, Andreas; Zimmermann, Egon; Vereecken, Harry

    2013-04-01

    The spatial distribution of unsaturated hydraulic conductivity in the subsurface is of importance for hydrological modeling. Conventional methods to determine unsaturated hydraulic properties in the field are invasive and typically have a poor spatial resolution. In order to overcome these drawbacks, geophysical methods have received much attention in the last decades. Recent results of electrical impedance spectroscopy (EIS) on a range of saturated and unsaturated porous media revealed promising relationships between spectral electrical and hydraulic properties. Therefore, spectral electrical impedance tomography (EIT) is a promising method to image hydraulic properties in the subsurface. While this approach is emerging for aquifer characterization, unsaturated hydraulic properties have not yet been determined by EIT. In order to do so, a laboratory setup has been developed to perform controlled infiltration, drainage and stationary flow experiments on soil columns. A lysimeter with a height of 50 cm and a diameter of 22 cm is equipped with 40 electrodes and 4 tensiometers. An irrigation device at the top controlled by a peristaltic pump is used for a constant and homogeneous infiltration. Outflow is controlled by a suction plate at the bottom where an adjustable vacuum of up to 500 hPa can be applied. In a first measurement series, spectral EIT measurements were performed on a homogeneous sand column during stepwise drainage of the saturated porous medium using predefined pressure at the bottom. First results show that with decreasing water content the low frequency phase shift of complex electrical conductivity increases. This is consistent with previously reported EIS results. Calibrated relationships between electrical and hydraulic properties were used to convert the resulting electrical into hydraulic conductivity images.

  20. Double-arm three-dimensional ion imaging apparatus for the study of ion pair channels in resonance enhanced multiphoton ionization

    NASA Astrophysics Data System (ADS)

    Poretskiy, M. S.; Chichinin, A. I.; Maul, C.; Gericke, K.-H.

    2016-02-01

    We present a novel experimental configuration for the full quantitative characterization of the multichannel resonance enhanced multiphoton ionization (REMPI) of small molecules in cases when the ion-pair dissociation channel is important. For this purpose, a double-arm time-of-flight mass spectrometer with three-dimensional (3D) ion imaging detectors at both arms is constructed. The REMPI of HCl molecules is used to examine the constructed setup. The apparatus allows us to perform simultaneous measurements of the 3D velocity vector distributions of positive (H+, HCl+, and Cl+) and negative (Cl-) photoions. The characterization consists of the determination of "two-photon absorption cross sections" for the process HCl(X)+2hν → HCl∗, one-photon absorption cross sections for subsequent processes HCl∗ + hν → HCl∗∗, and the probability of the subsequent non-adiabatic transition HCl∗∗ → HCl(B) → H+ + Cl-, which leads to ionic pairs. All these data should be obtained from the analysis of the dependencies of the number of ions on the laser energy. The full characterization of the laser beam and the knowledge of the ion detection probability are necessary parts of the analysis. Detailed knowledge of losses of produced ions in the mass spectrometer before detection requires understanding and characterization of such processes like electron emission from metallic grids under ion bombardment or charge transfer between positive ions and the metal surface of the grids, like Cl+ + (grid) → Cl-. These important phenomena from surface science are rarely discussed in the imaging literature, and here, we try to compensate for this shortcoming.

  1. Double-arm three-dimensional ion imaging apparatus for the study of ion pair channels in resonance enhanced multiphoton ionization.

    PubMed

    Poretskiy, M S; Chichinin, A I; Maul, C; Gericke, K-H

    2016-02-01

    We present a novel experimental configuration for the full quantitative characterization of the multichannel resonance enhanced multiphoton ionization (REMPI) of small molecules in cases when the ion-pair dissociation channel is important. For this purpose, a double-arm time-of-flight mass spectrometer with three-dimensional (3D) ion imaging detectors at both arms is constructed. The REMPI of HCl molecules is used to examine the constructed setup. The apparatus allows us to perform simultaneous measurements of the 3D velocity vector distributions of positive (H(+), HCl(+), and Cl(+)) and negative (Cl(-)) photoions. The characterization consists of the determination of "two-photon absorption cross sections" for the process HCl(X)+2hν → HCl*, one-photon absorption cross sections for subsequent processes HCl* + hν → HCl*, and the probability of the subsequent non-adiabatic transition HCl* → HCl(B) → H(+) + Cl(-), which leads to ionic pairs. All these data should be obtained from the analysis of the dependencies of the number of ions on the laser energy. The full characterization of the laser beam and the knowledge of the ion detection probability are necessary parts of the analysis. Detailed knowledge of losses of produced ions in the mass spectrometer before detection requires understanding and characterization of such processes like electron emission from metallic grids under ion bombardment or charge transfer between positive ions and the metal surface of the grids, like Cl(+) + (grid) → Cl(-). These important phenomena from surface science are rarely discussed in the imaging literature, and here, we try to compensate for this shortcoming. PMID:26931834

  2. Multi-photon excited luminescence of magnetic FePt core-shell nanoparticles

    PubMed Central

    Seemann, K.M.; Kuhn, B.

    2014-01-01

    We present magnetic FePt nanoparticles with a hydrophilic, inert, and biocompatible silico-tungsten oxide shell. The particles can be functionalized, optically detected, and optically manipulated. To show the functionalization the fluorescent dye NOPS was bound to the FePt core-shell nanoparticles with propyl-triethoxy-silane linkers and fluorescence of the labeled particles were observed in ethanol (EtOH). In aqueous dispersion the NOPS fluorescence is quenched making them invisible using 1-photon excitation. However, we observe bright luminescence of labeled and even unlabeled magnetic core-shell nanoparticles with multi-photon excitation. Luminescence can be detected in the near ultraviolet and the full visible spectral range by near infrared multi-photon excitation. For optical manipulation, we were able to drag clusters of particles, and maybe also single particles, by a focused laser beam that acts as optical tweezers by inducing an electric dipole in the insulated metal nanoparticles. In a first application, we show that the luminescence of the core-shell nanoparticles is bright enough for in vivo multi-photon imaging in the mouse neocortex down to cortical layer 5. PMID:25071977

  3. Improving Image Quality of Bronchial Arteries with Virtual Monochromatic Spectral CT Images

    PubMed Central

    Ma, Guangming; He, Taiping; Yu, Yong; Duan, Haifeng; Yang, Chuangbo

    2016-01-01

    Objective To evaluate the clinical value of using monochromatic images in spectral CT pulmonary angiography to improve image quality of bronchial arteries. Methods We retrospectively analyzed the chest CT images of 38 patients who underwent contrast-enhanced spectral CT. These images included a set of 140kVp polychromatic images and the default 70keV monochromatic images. Using the standard Gemstone Spectral Imaging (GSI) viewer on an advanced workstation (AW4.6,GE Healthcare), an optimal energy level (in keV) for obtaining the best contrast-to-noise ratio (CNR) for the artery could be automatically obtained. The signal-to-noise ratio (SNR), CNR and objective image quality score (1–5) for these 3 image sets (140kVp, 70keV and optimal energy level) were obtained and, statistically compared. The image quality score consistency between the two observers was also evaluated using Kappa test. Results The optimal energy levels for obtaining the best CNR were 62.58±2.74keV.SNR and CNR from the 140kVp polychromatic, 70keV and optimal keV monochromatic images were (16.44±5.85, 13.24±5.52), (20.79±7.45, 16.69±6.27) and (24.9±9.91, 20.53±8.46), respectively. The corresponding subjective image quality scores were 1.97±0.82, 3.24±0.75, and 4.47±0.60. SNR, CNR and subjective scores had significant difference among groups (all p<0.001). The optimal keV monochromatic images were superior to the 70keV monochromatic and 140kVp polychromatic images, and there was high agreement between the two observers on image quality score (kappa>0.80). Conclusions Virtual monochromatic images at approximately 63keV in dual-energy spectral CT pulmonary angiography yielded the best CNR and highest diagnostic confidence for imaging bronchial arteries. PMID:26967737

  4. Color camera computed tomography imaging spectrometer for improved spatial-spectral image accuracy

    NASA Technical Reports Server (NTRS)

    Wilson, Daniel W. (Inventor); Bearman, Gregory H. (Inventor); Johnson, William R. (Inventor)

    2011-01-01

    Computed tomography imaging spectrometers ("CTIS"s) having color focal plane array detectors are provided. The color FPA detector may comprise a digital color camera including a digital image sensor, such as a Foveon X3.RTM. digital image sensor or a Bayer color filter mosaic. In another embodiment, the CTIS includes a pattern imposed either directly on the object scene being imaged or at the field stop aperture. The use of a color FPA detector and the pattern improves the accuracy of the captured spatial and spectral information.

  5. Imaging spectral signature satellite instrument for the real-time identification of ground scenes with a dedicated spectral signature

    NASA Astrophysics Data System (ADS)

    Kantojärvi, Uula; Saari, Heikki; Viherkanto, Kai; Herrala, Esko; Harnisch, Bernd

    2007-05-01

    With hyperspectral pushbroom imaging spectrometers on Earth observation satellites it is possible to detect and identify dedicated ground pixels by their spectral signature. Conventional time consuming on-ground processing performs this selection by processing the measured hyperspectral data cube of the image. The Imaging Spectral Signature Instrument (ISSI) concept combines an optical on-board processing of the hyperspectral data cube with a thresholding algorithm, to identify pixels with a pre-defined and programmable spectral signature, such as water, forest and minerals, in the ground swath. The Imaging Spectral Signature Instrument consists of an imaging telescope, which images an object line on the entrance slit of a first imaging spectrometer, which disperses each pixel of the object line into its spectral content and images the hyperspectral image on the spatial light modulator. This spatial light modulator will be programmed with a spatial transmission or reflection behavior, which is constant along the spatial pixels and along the spectral pixels identical to a filter vector that corresponds to the spectral signature of the searched specific feature. A second inverted spectrometer reimages the by the first spectrometer dispersed and by the spatial light modulator transmitted or reflected flux into a line of pixels. In case the spectral content of the ground scene is identical to the searched signature, the flux traversing or reflecting the spatial light modulator will be maximum. The related pixel can be identified in the final image as a high signal by a threshold discriminator. A component test setup consists of an imaging lens, two Imspector™ spectrographs, a spatial light modulator, which is a programmable transmissible liquid crystal display and a CCD sensor as a detector. A mathematical model was developed for the instrument and its performance was evaluated in order to compare different concept variations. All components were measured and

  6. Miniature Compressive Ultra-spectral Imaging System Utilizing a Single Liquid Crystal Phase Retarder.

    PubMed

    August, Isaac; Oiknine, Yaniv; AbuLeil, Marwan; Abdulhalim, Ibrahim; Stern, Adrian

    2016-01-01

    Spectroscopic imaging has been proved to be an effective tool for many applications in a variety of fields, such as biology, medicine, agriculture, remote sensing and industrial process inspection. However, due to the demand for high spectral and spatial resolution it became extremely challenging to design and implement such systems in a miniaturized and cost effective manner. Using a Compressive Sensing (CS) setup based on a single variable Liquid Crystal (LC) retarder and a sensor array, we present an innovative Miniature Ultra-Spectral Imaging (MUSI) system. The LC retarder acts as a compact wide band spectral modulator. Within the framework of CS, a sequence of spectrally modulated images is used to recover ultra-spectral image cubes. Using the presented compressive MUSI system, we demonstrate the reconstruction of gigapixel spatio-spectral image cubes from spectral scanning shots numbering an order of magnitude less than would be required using conventional systems. PMID:27004447

  7. Experimental demonstration of an adaptive architecture for direct spectral imaging classification.

    PubMed

    Dunlop-Gray, Matthew; Poon, Phillip K; Golish, Dathon; Vera, Esteban; Gehm, Michael E

    2016-08-01

    Spectral imaging is a powerful tool for providing in situ material classification across a spatial scene. Typically, spectral imaging analyses are interested in classification, though often the classification is performed only after reconstruction of the spectral datacube. We present a computational spectral imaging system, the Adaptive Feature-Specific Spectral Imaging Classifier (AFSSI-C), which yields direct classification across the spatial scene without reconstruction of the source datacube. With a dual disperser architecture and a programmable spatial light modulator, the AFSSI-C measures specific projections of the spectral datacube which are generated by an adaptive Bayesian classification and feature design framework. We experimentally demonstrate multiple order-of-magnitude improvement of classification accuracy in low signal-to-noise (SNR) environments when compared to legacy spectral imaging systems. PMID:27505794

  8. Miniature Compressive Ultra-spectral Imaging System Utilizing a Single Liquid Crystal Phase Retarder

    NASA Astrophysics Data System (ADS)

    August, Isaac; Oiknine, Yaniv; Abuleil, Marwan; Abdulhalim, Ibrahim; Stern, Adrian

    2016-03-01

    Spectroscopic imaging has been proved to be an effective tool for many applications in a variety of fields, such as biology, medicine, agriculture, remote sensing and industrial process inspection. However, due to the demand for high spectral and spatial resolution it became extremely challenging to design and implement such systems in a miniaturized and cost effective manner. Using a Compressive Sensing (CS) setup based on a single variable Liquid Crystal (LC) retarder and a sensor array, we present an innovative Miniature Ultra-Spectral Imaging (MUSI) system. The LC retarder acts as a compact wide band spectral modulator. Within the framework of CS, a sequence of spectrally modulated images is used to recover ultra-spectral image cubes. Using the presented compressive MUSI system, we demonstrate the reconstruction of gigapixel spatio-spectral image cubes from spectral scanning shots numbering an order of magnitude less than would be required using conventional systems.

  9. Miniature Compressive Ultra-spectral Imaging System Utilizing a Single Liquid Crystal Phase Retarder

    PubMed Central

    August, Isaac; Oiknine, Yaniv; AbuLeil, Marwan; Abdulhalim, Ibrahim; Stern, Adrian

    2016-01-01

    Spectroscopic imaging has been proved to be an effective tool for many applications in a variety of fields, such as biology, medicine, agriculture, remote sensing and industrial process inspection. However, due to the demand for high spectral and spatial resolution it became extremely challenging to design and implement such systems in a miniaturized and cost effective manner. Using a Compressive Sensing (CS) setup based on a single variable Liquid Crystal (LC) retarder and a sensor array, we present an innovative Miniature Ultra-Spectral Imaging (MUSI) system. The LC retarder acts as a compact wide band spectral modulator. Within the framework of CS, a sequence of spectrally modulated images is used to recover ultra-spectral image cubes. Using the presented compressive MUSI system, we demonstrate the reconstruction of gigapixel spatio-spectral image cubes from spectral scanning shots numbering an order of magnitude less than would be required using conventional systems. PMID:27004447

  10. Comparison of spectral CT imaging methods based a photon-counting detector: Experimental study

    NASA Astrophysics Data System (ADS)

    Lee, Youngjin; Lee, Seungwan; Kim, Hee-Joung

    2016-04-01

    Photon-counting detectors allow spectral computed tomography (CT) imaging using energy-resolved information from a polychromatic X-ray spectrum. The spectral CT images based on the photon-counting detectors are dependent on the energy ranges defined by energy bins for image acquisition. In this study, K-edge and energy weighting imaging methods were experimentally implemented by using a spectral CT system with a cadmium zinc telluride (CZT)-based photon-counting detector. The spectral CT images were obtained by various energy bins and compared in terms of CNR improvement for investigating the effect of energy bins and the efficiency of the spectral CT imaging methods. The results showed that the spectral CT image quality was improved by using the particular energy bins, which were optimized for each spectral CT imaging method and target material. The CNR improvement was different for the spectral CT imaging methods and target materials. It can be concluded that an appropriate selection of imaging method for each target material and the optimization of energy bin can maximize the quality of spectral CT images.

  11. Spectral imager based on Fabry-Perot interferometer for Aalto-1 nanosatellite

    NASA Astrophysics Data System (ADS)

    Mannila, Rami; Näsilä, Antti; Viherkanto, Kai; Holmlund, Christer; Näkki, Ismo; Saari, Heikki

    2013-09-01

    The Aalto-1 is a 3U-cubesat project coordinated by Aalto University. The satellite, Aalto-1, will be mainly built by students as project assignments and thesis works. The Aalto-1 is planned to launch on 2014. VTT Technical Research Centre of Finland is developing the main Earth observation payload, a miniaturized spectral imager unit, for the satellite. The spectral imager unit contains a spectral imager, a visible RGB-camera and control electronics of the cameras. Detailed design of the spectral imager unit has been completed and assembly of the spectral imager unit will be done in the autumn 2013. The spectral imager is based on a tunable Fabry-Perot interferometer (FPI) accompanied by an RGB CMOS image sensor. The FPI consists of two highly reflective surfaces separated by a tunable air gap and it is based on a piezo-actuated structure. The piezo-actuated FPI uses three piezo-actuators and is controlled in a closed capacitive feedback loop. The spectral resolution of the imager will be 8-15 nm at full width at half maximum and it will operate in the wavelength range 500-900 nm. Imaging resolution of the spectral imager is 1024x1024 pixels and the focal length of the optics is 32 mm and F-number is 3.4. Mass of the spectral imager unit is approximately 600 grams, and dimensions are 97 mm x 97 mm x 48 mm.

  12. An excitation wavelength-scanning spectral imaging system for preclinical imaging

    NASA Astrophysics Data System (ADS)

    Leavesley, Silas; Jiang, Yanan; Patsekin, Valery; Rajwa, Bartek; Robinson, J. Paul

    2008-02-01

    Small-animal fluorescence imaging is a rapidly growing field, driven by applications in cancer detection and pharmaceutical therapies. However, the practical use of this imaging technology is limited by image-quality issues related to autofluorescence background from animal tissues, as well as attenuation of the fluorescence signal due to scatter and absorption. To combat these problems, spectral imaging and analysis techniques are being employed to separate the fluorescence signal from background autofluorescence. To date, these technologies have focused on detecting the fluorescence emission spectrum at a fixed excitation wavelength. We present an alternative to this technique, an imaging spectrometer that detects the fluorescence excitation spectrum at a fixed emission wavelength. The advantages of this approach include increased available information for discrimination of fluorescent dyes, decreased optical radiation dose to the animal, and ability to scan a continuous wavelength range instead of discrete wavelength sampling. This excitation-scanning imager utilizes an acousto-optic tunable filter (AOTF), with supporting optics, to scan the excitation spectrum. Advanced image acquisition and analysis software has also been developed for classification and unmixing of the spectral image sets. Filtering has been implemented in a single-pass configuration with a bandwidth (full width at half maximum) of 16nm at 550nm central diffracted wavelength. We have characterized AOTF filtering over a wide range of incident light angles, much wider than has been previously reported in the literature, and we show how changes in incident light angle can be used to attenuate AOTF side lobes and alter bandwidth. A new parameter, in-band to out-of-band ratio, was defined to assess the quality of the filtered excitation light. Additional parameters were measured to allow objective characterization of the AOTF and the imager as a whole. This is necessary for comparing the

  13. Spectral imaging to visualize higher-order genomic organization.

    PubMed

    Sawyer, Iain A; Shevtsov, Sergei P; Dundr, Miroslav

    2016-05-01

    A concern in the field of genomics is the proper interpretation of large, high-throughput sequencing datasets. The use of DNA FISH followed by high-content microscopy is a valuable tool for validation and contextualization of frequently occurring gene pairing events at the single-cell level identified by deep sequencing. However, these techniques possess certain limitations. Firstly, they do not permit the study of colocalization of many gene loci simultaneously. Secondly, the direct assessment of the relative position of many clustered gene loci within their respective chromosome territories is impossible. Thus, methods are required to advance the study of higher-order nuclear and cellular organization. Here, we describe a multiplexed DNA FISH technique combined with indirect immunofluorescence to study the relative position of 6 distinct genomic or cellular structures. This can be achieved in a single hybridization step using spectral imaging during image acquisition and linear unmixing. Here, we detail the use of this method to quantify gene pairing between highly expressed spliceosomal genes and compare these data to randomly positioned in silico simulated gene clusters. This is a potentially universally applicable approach for the validation of 3C-based technologies, deep imaging of spatial organization within the nucleus and global cellular organization. PMID:27167405

  14. Spectrally Resolved Magnetic Resonance Imaging of the XenonBiosensor

    SciTech Connect

    Hilty, Christian; Lowery, Thomas; Wemmer, David; Pines, Alexander

    2005-07-15

    Due to its ability to non-invasively record images, as well as elucidate molecular structure, nuclear magnetic resonance is the method of choice for applications as widespread as chemical analysis and medical diagnostics. Its detection threshold is, however, limited by the small polarization of nuclear spins in even the highest available magnetic fields. This limitation can, under certain circumstances, be alleviated by using hyper-polarized substances. Xenon biosensors make use of the sensitivity gain of hyperpolarized xenon to provide magnetic resonance detection capability for a specific low-concentration target. They consist of a cryptophane cage, which binds one xenon atom, and which has been connected via a linker to a targeting moiety such as a ligand or antibody. Recent work has shown the possibility of using the xenon biosensor to detect small amounts of a substance in a heterogeneous environment by NMR. Here, we demonstrate that magnetic resonance (MR) provides the capability to obtain spectrally and spatially resolved images of the distribution of immobilized biosensor, opening the possibility for using the xenon biosensor for targeted imaging.

  15. Exploiting spectral content for image segmentation in GPR data

    NASA Astrophysics Data System (ADS)

    Wang, Patrick K.; Morton, Kenneth D., Jr.; Collins, Leslie M.; Torrione, Peter A.

    2011-06-01

    Ground-penetrating radar (GPR) sensors provide an effective means for detecting changes in the sub-surface electrical properties of soils, such as changes indicative of landmines or other buried threats. However, most GPR-based pre-screening algorithms only localize target responses along the surface of the earth, and do not provide information regarding an object's position in depth. As a result, feature extraction algorithms are forced to process data from entire cubes of data around pre-screener alarms, which can reduce feature fidelity and hamper performance. In this work, spectral analysis is investigated as a method for locating subsurface anomalies in GPR data. In particular, a 2-D spatial/frequency decomposition is applied to pre-screener flagged GPR B-scans. Analysis of these spatial/frequency regions suggests that aspects (e.g. moments, maxima, mode) of the frequency distribution of GPR energy can be indicative of the presence of target responses. After translating a GPR image to a function of the spatial/frequency distributions at each pixel, several image segmentation approaches can be applied to perform segmentation in this new transformed feature space. To illustrate the efficacy of the approach, a performance comparison between feature processing with and without the image segmentation algorithm is provided.

  16. Hyper-spectral imaging of aircraft exhaust plumes

    NASA Astrophysics Data System (ADS)

    Bowen, Spencer; Bradley, Kenneth; Gross, Kevin; Perram, Glen; Marciniak, Michael

    2008-10-01

    An imaging Fourier-transform spectrometer has been used to determine low spatial resolution temperature and chemical species concentration distributions of aircraft jet engine exhaust plumes. An overview of the imaging Fourier transform spectrometer and the methodology of the project is presented. Results to date are shared and future work is discussed. Exhaust plume data from a Turbine Technologies, LTD, SR-30 turbojet engine at three engine settings was collected using a Telops Field-portable Imaging Radiometric Spectrometer Technology Mid-Wave Extended (FIRST-MWE). Although the plume exhibited high temporal frequency fluctuations, temporal averaging of hyper-spectral data-cubes produced steady-state distributions, which, when co-added and Fourier transformed, produced workable spectra. These spectra were then reduced using a simplified gaseous effluent model to fit forward-modeled spectra obtained from the Line-By-Line Radiative Transfer Model (LBLRTM) and the high-resolution transmission (HITRAN) molecular absorption database to determine approximate temperature and concentration distributions. It is theorized that further development of the physical model will produce better agreement between measured and modeled data.

  17. The Spectral and Photometric Imaging Receiver for Herschel

    NASA Astrophysics Data System (ADS)

    Lu, Nanyao Y.; Schulz, B.; Shupe, D.; Xu, C. K.; Schwartz, A.; Zhang, L.; ICC, SPIRE

    2010-01-01

    The Spectral and Photometric Imaging REceiver (SPIRE) is one of the three instruments on board the European Space Agency's Herschel Space Observatory launched on May 14, 2009. SPIRE features an imaging photometer with passbands centered at 250, 350 and 500 microns, and an imaging Fourier transform spectrometer covering the wavelength range between 194 and 672 microns. In view of its latest performance verification results, we describe the updated SPIRE instrumental capabilities, and its scientific potential. The instrument was developed by a consortium of European and American scientists, led by P.I. Prof. M. Griffin of Cardiff University (UK). The US is playing a crucial role in SPIRE, by providing its bolometer arrays (developed by Dr. J. Bock at JPL), participating in SPIRE's ground and in-flight commissioning and calibration, and in the development of the Herschel Common Science System (HCSS) data reduction software. Support for both Key and Open Time Programs of US astronomers is provided by the NASA Herschel Science Center (NHSC) at the Infrared Processing and Analysis Center (IPAC).

  18. Integrated coherent Raman scattering and multiphoton microscopy for label-free imaging of the dentin in the tooth

    NASA Astrophysics Data System (ADS)

    Wang, Zi; Zheng, Wei; Lin, Jian; Hsu, Chin-Ying; Huang, Zhiwei

    2014-02-01

    We report the implementation of a unique multimodal nonlinear optical microscopy (i.e., coherent anti-Stokes Raman scattering (CARS), second harmonic generation (SHG), third harmonic generation (THG) and two photon excitation fluorescence (TPEF)) platform for label-free imaging of dentin. A picosecond tunable laser together with an OPO is used as the excitation source for simultaneously multimodal imaging. CARS shows similar information as TPEF in dentin, but it has a higher sectioning performance than TPEF and thus it is a good alternative for TPEF. Microtubule structure is revealed nearby dentin enamel junction (DEJ) from the multimodal images. This work demonstrates that combining different nonlinear optical imaging modalities can provide new insights into the understanding of morphological structures and biochemical/biomolecular distributions of the dentine without the need of labeling.

  19. Terahertz detectors for long wavelength multi-spectral imaging.

    SciTech Connect

    Lyo, Sungkwun Kenneth; Wanke, Michael Clement; Reno, John Louis; Shaner, Eric Arthur; Grine, Albert D.

    2007-10-01

    The purpose of this work was to develop a wavelength tunable detector for Terahertz spectroscopy and imaging. Our approach was to utilize plasmons in the channel of a specially designed field-effect transistor called the grating-gate detector. Grating-gate detectors exhibit narrow-linewidth, broad spectral tunability through application of a gate bias, and no angular dependence in their photoresponse. As such, if suitable sensitivity can be attained, they are viable candidates for Terahertz multi-spectral focal plane arrays. When this work began, grating-gate gate detectors, while having many promising characteristics, had a noise-equivalent power (NEP) of only 10{sup -5} W/{radical}Hz. Over the duration of this project, we have obtained a true NEP of 10{sup -8} W/{radical}Hz and a scaled NEP of 10{sup -9}W/{radical}Hz. The ultimate goal for these detectors is to reach a NEP in the 10{sup -9{yields}-10}W/{radical}Hz range; we have not yet seen a roadblock to continued improvement.

  20. Spectral localization by imaging using multielement receiver coils.

    PubMed

    An, Li; Warach, Steven; Shen, Jun

    2011-07-01

    A new spectral localization technique for in vivo magnetic resonance spectroscopy is introduced. Structural information extracted from anatomical imaging is used for defining compartments which provide the basis for spectral localization. The inherent spatial heterogeneity of multiple receiver coil elements is used along with optional phase encoding to resolve signals from different compartments. This technique allows a few compartmental spectra to be reconstructed from multichannel data acquired with no or very few phase encoding steps, resulting in short scan time and high efficiency. Alternatively, this technique also allows a significant number of compartmental spectra to be reconstructed if sufficient phase encoding steps are used. A procedure is developed to semiautomatically generate a significant number of compartments of comparable sizes, which allows one to obtain spectra from small regions of interest with curvilinear shapes. This may be useful for obtaining spectra from relatively small stroke lesions or tumors. Phantom experiments and in vivo magnetic resonance spectroscopy of stroke patients have been performed to demonstrate this technique. PMID:21287595

  1. Video-rate resonant scanning multiphoton microscopy

    PubMed Central

    Kirkpatrick, Nathaniel D.; Chung, Euiheon; Cook, Daniel C.; Han, Xiaoxing; Gruionu, Gabriel; Liao, Shan; Munn, Lance L.; Padera, Timothy P.; Fukumura, Dai; Jain, Rakesh K.

    2013-01-01

    The abnormal tumor microenvironment fuels tumor progression, metastasis, immune suppression, and treatment resistance. Over last several decades, developments in and applications of intravital microscopy have provided unprecedented insights into the dynamics of the tumor microenvironment. In particular, intravital multiphoton microscopy has revealed the abnormal structure and function of tumor-associated blood and lymphatic vessels, the role of aberrant tumor matrix in drug delivery, invasion and metastasis of tumor cells, the dynamics of immune cell trafficking to and within tumors, and gene expression in tumors. However, traditional multiphoton microscopy suffers from inherently slow imaging rates—only a few frames per second, thus unable to capture more rapid events such as blood flow, lymphatic flow, and cell movement within vessels. Here, we report the development and implementation of a video-rate multiphoton microscope (VR-MPLSM) based on resonant galvanometer mirror scanning that is capable of recording at 30 frames per second and acquiring intravital multispectral images. We show that the design of the system can be readily implemented and is adaptable to various experimental models. As examples, we demonstrate the utility of the system to directly measure flow within tumors, capture metastatic cancer cells moving within the brain vasculature and cells in lymphatic vessels, and image acute responses to changes in a vascular network. VR-MPLSM thus has the potential to further advance intravital imaging and provide new insight into the biology of the tumor microenvironment. PMID:24353926

  2. Unsupervised learning of cone spectral classes from natural images.

    PubMed

    Benson, Noah C; Manning, Jeremy R; Brainard, David H

    2014-06-01

    The first step in the evolution of primate trichromatic color vision was the expression of a third cone class not present in ancestral mammals. This observation motivates a fundamental question about the evolution of any sensory system: how is it possible to detect and exploit the presence of a novel sensory class? We explore this question in the context of primate color vision. We present an unsupervised learning algorithm capable of both detecting the number of spectral cone classes in a retinal mosaic and learning the class of each cone using the inter-cone correlations obtained in response to natural image input. The algorithm's ability to classify cones is in broad agreement with experimental evidence about functional color vision for a wide range of mosaic parameters, including those characterizing dichromacy, typical trichromacy, anomalous trichromacy, and possible tetrachromacy. PMID:24967877

  3. Martian spectral units derived from ISM imaging spectrometer data

    NASA Technical Reports Server (NTRS)

    Murchie, S.; Mustard, J.; Saylor, R.

    1993-01-01

    Based on results of the Viking mission, the soil layer of Mars has been thought to be fairly homogeneous and to consist of a mixture of as few as two components, a 'dark gray' basaltic material and a 'bright red' altered material. However, near-infrared reflectance spectra measured recently both telescopically and from spacecraft indicate compositional heterogeneity beyond what can be explained by just two components. In particular, data from the ISM imaging spectrometer, which observed much of the equatorial region at a spatial resolution of approximately 22 km, indicate spatial differences in the presence and abundance of Fe-containing phases, hydroxylated silicates, and H2O. The ISM data was used to define, characterize, and map soil 'units' based on their spectral properties. The spatial distribution of these 'units' were compared to morphologic, visible color, and thermal inertia features recognized in Viking data.

  4. Spectrally balanced detection for optical frequency domain imaging.

    PubMed

    Chen, Yueli; de Bruin, Daniel M; Kerbage, Charles; de Boer, Johannes F

    2007-12-10

    In optical frequency domain imaging (OFDI) or swept-source optical coherence tomography, balanced detection is required to suppress relative intensity noise (RIN). A regular implementation of balanced detection by combining reference and sample arm signal in a 50/50 coupler and detecting the differential output with a balanced receiver is however, not perfect. Since the splitting ratio of the 50/50 coupler is wavelength dependent, RIN is not optimally canceled at the edges of the wavelength sweep. The splitting ratio has a nearly linear shift of 0.4% per nanometer. This brings as much as +/-12% deviation at the margins of wavelength-swept range centered at 1060nm. We demonstrate a RIN suppression of 33dB by spectrally corrected balanced detection, 11dB more that regular balanced detection. PMID:19550929

  5. Method for detection and imaging over a broad spectral range

    DOEpatents

    Yefremenko, Volodymyr; Gordiyenko, Eduard; Pishko, legal representative, Olga; Novosad, Valentyn; Pishko, deceased; Vitalii

    2007-09-25

    A method of controlling the coordinate sensitivity in a superconducting microbolometer employs localized light, heating or magnetic field effects to form normal or mixed state regions on a superconducting film and to control the spatial location. Electron beam lithography and wet chemical etching were applied as pattern transfer processes in epitaxial Y--Ba--Cu--O films. Two different sensor designs were tested: (i) a 3 millimeter long and 40 micrometer wide stripe and (ii) a 1.25 millimeters long, and 50 micron wide meandering-like structure. Scanning the laser beam along the stripe leads to physical displacement of the sensitive area, and, therefore, may be used as a basis for imaging over a broad spectral range. Forming the superconducting film as a meandering structure provides the equivalent of a two-dimensional detector array. Advantages of this approach are simplicity of detector fabrication, and simplicity of the read-out process requiring only two electrical terminals.

  6. Unsupervised Learning of Cone Spectral Classes from Natural Images

    PubMed Central

    Benson, Noah C.; Manning, Jeremy R.; Brainard, David H.

    2014-01-01

    The first step in the evolution of primate trichromatic color vision was the expression of a third cone class not present in ancestral mammals. This observation motivates a fundamental question about the evolution of any sensory system: how is it possible to detect and exploit the presence of a novel sensory class? We explore this question in the context of primate color vision. We present an unsupervised learning algorithm capable of both detecting the number of spectral cone classes in a retinal mosaic and learning the class of each cone using the inter-cone correlations obtained in response to natural image input. The algorithm's ability to classify cones is in broad agreement with experimental evidence about functional color vision for a wide range of mosaic parameters, including those characterizing dichromacy, typical trichromacy, anomalous trichromacy, and possible tetrachromacy. PMID:24967877

  7. Research on method of geometry and spectral calibration of pushbroom dispersive hyperspectral imager

    NASA Astrophysics Data System (ADS)

    He, Zhiping; Shu, Rong; Wang, Jianyu

    2012-11-01

    Development and application of airborne and aerospace hyperspectral imager press for high precision geometry and spectral calibration of pixels of image cube. The research of geometry and spectral calibration of pushbroom hyperspectral imager, its target is giving the coordinate of angle field of view and center wavelength of each detect unit in focal plane detector of hyperspectral imager, and achieves the high precision, full field of view, full channel geometry and spectral calibration. It is importance for imaging quantitative and deep application of hyperspectal imager. The paper takes the geometry and spectral calibration of pushbroom dispersive hyperspectral imager as case study, and research on the constitution and analysis of imaging mathematical model. Aimed especially at grating-dispersive hyperspectral imaging, the specialty of the imaging mode and dispersive method has been concretely analyzed. Based on the analysis, the theory and feasible method of geometry and spectral calibration of dispersive hyperspectral imager is set up. The key technique has been solved is As follows: 1). the imaging mathematical model and feasible method of geometry and spectral calibration for full pixels of image cube has been set up, the feasibility of the calibration method has been analyzed. 2). the engineering model and method of the geometry and spectral calibration of pushbroom dispersive hyperspectral imager has been set up and the calibration equipment has been constructed, and the calibration precision has been analyzed.

  8. First Radio Burst Imaging Observation From Mingantu Ultrawide Spectral Radioheliograph

    NASA Astrophysics Data System (ADS)

    Yan, Yihua; Chen, Linjie; Yu, Sijie; CSRH Team

    2015-08-01

    Radio imaging spectroscopy over wide range wavelength in dm/cm-bands will open new windows on solar flares and coronal mass ejections by tracing the radio emissions from accelerated electrons. The Chinese Spectral Radioheliograph (CSRH) with two arrays in 400MHz-2GHz /2-15GHz ranges with 64/532 frequency channels have been established in Mingantu Observing Station, Inner Mongolia of China, since 2013 and is in test observations now. CSRH is renamed as MUSER (Mingantu Ultrawide SpEctral Radioheliograph) after it's accomplishment We will introduce the progress and current status of CSRH. Some preliminary results of CSRH will be presented.On 11 Nov2014, the first burst event was registered by MUSER-I array at 400MHz-2GHz waveband. According to SGD event list there was a C-class flare peaked at 04:49UT in the disk center and the radio bursts around 04:22-04:24UT was attributed to this flare. However, MUSER-I image observation of the burst indicates that the radio burst peaked around 04:22UT was due to the eruption at the east limb of the Sun and connected to a CME appeared in that direction about 1 hour later. This demonstrate the importance of the spectroscopy observation of the solar radio burst.Acknowledgement: The CSRH team includes Wei Wang, Zhijun Chen, Fei Liu, Lihong Geng and Jian Zhang and CSRH project is supported by National Major Scientific Equipment R&D Project ZDYZ2009-3. The research was also supported by NSFC grants (11433006, 11221063), MOST grant (MOST2011CB811401), CAS Pilot-B Project (XDB09000000) and Marie Curie PIRSES- GA-295272-RADIOSUN.

  9. Interferometric and nonlinear-optical spectral-imaging techniques for outer space and live cells

    NASA Astrophysics Data System (ADS)

    Itoh, Kazuyoshi

    2015-12-01

    Multidimensional signals such as the spectral images allow us to have deeper insights into the natures of objects. In this paper the spectral imaging techniques that are based on optical interferometry and nonlinear optics are presented. The interferometric imaging technique is based on the unified theory of Van Cittert-Zernike and Wiener-Khintchine theorems and allows us to retrieve a spectral image of an object in the far zone from the 3D spatial coherence function. The retrieval principle is explained using a very simple object. The promising applications to space interferometers for astronomy that are currently in progress will also be briefly touched on. An interesting extension of interferometric spectral imaging is a 3D and spectral imaging technique that records 4D information of objects where the 3D and spectral information is retrieved from the cross-spectral density function of optical field. The 3D imaging is realized via the numerical inverse propagation of the cross-spectral density. A few techniques suggested recently are introduced. The nonlinear optical technique that utilizes stimulated Raman scattering (SRS) for spectral imaging of biomedical targets is presented lastly. The strong signals of SRS permit us to get vibrational information of molecules in the live cell or tissue in real time. The vibrational information of unstained or unlabeled molecules is crucial especially for medical applications. The 3D information due to the optical nonlinearity is also the attractive feature of SRS spectral microscopy.

  10. Development of a real-time flexible multiphoton microendoscope for label-free imaging in a live animal

    NASA Astrophysics Data System (ADS)

    Ducourthial, Guillaume; Leclerc, Pierre; Mansuryan, Tigran; Fabert, Marc; Brevier, Julien; Habert, Rémi; Braud, Flavie; Batrin, Renaud; Vever-Bizet, Christine; Bourg-Heckly, Geneviève; Thiberville, Luc; Druilhe, Anne; Kudlinski, Alexandre; Louradour, Frédéric

    2015-12-01

    We present a two-photon microendoscope capable of in vivo label-free deep-tissue high-resolution fast imaging through a very long optical fiber. First, an advanced light-pulse spectro-temporal shaping device optimally precompensates for linear and nonlinear distortions occurring during propagation within the endoscopic fiber. This enables the delivery of sub-40-fs duration infrared excitation pulses at the output of 5 meters of fiber. Second, the endoscopic fiber is a custom-made double-clad polarization-maintaining photonic crystal fiber specifically designed to optimize the imaging resolution and the intrinsic luminescence backward collection. Third, a miniaturized fiber-scanner of 2.2 mm outer diameter allows simultaneous second harmonic generation (SHG) and two-photon excited autofluorescence (TPEF) imaging at 8 frames per second. This microendoscope’s transverse and axial resolutions amount respectively to 0.8 μm and 12 μm, with a field-of-view as large as 450 μm. This microendoscope’s unprecedented capabilities are validated during label-free imaging, ex vivo on various fixed human tissue samples, and in vivo on an anesthetized mouse kidney demonstrating an imaging penetration depth greater than 300 μm below the surface of the organ. The results reported in this manuscript confirm that nonlinear microendoscopy can become a valuable clinical tool for real-time in situ assessment of pathological states.

  11. Development of a real-time flexible multiphoton microendoscope for label-free imaging in a live animal

    PubMed Central

    Ducourthial, Guillaume; Leclerc, Pierre; Mansuryan, Tigran; Fabert, Marc; Brevier, Julien; Habert, Rémi; Braud, Flavie; Batrin, Renaud; Vever-Bizet, Christine; Bourg-Heckly, Geneviève; Thiberville, Luc; Druilhe, Anne; Kudlinski, Alexandre; Louradour, Frédéric

    2015-01-01

    We present a two-photon microendoscope capable of in vivo label-free deep-tissue high-resolution fast imaging through a very long optical fiber. First, an advanced light-pulse spectro-temporal shaping device optimally precompensates for linear and nonlinear distortions occurring during propagation within the endoscopic fiber. This enables the delivery of sub-40-fs duration infrared excitation pulses at the output of 5 meters of fiber. Second, the endoscopic fiber is a custom-made double-clad polarization-maintaining photonic crystal fiber specifically designed to optimize the imaging resolution and the intrinsic luminescence backward collection. Third, a miniaturized fiber-scanner of 2.2 mm outer diameter allows simultaneous second harmonic generation (SHG) and two-photon excited autofluorescence (TPEF) imaging at 8 frames per second. This microendoscope’s transverse and axial resolutions amount respectively to 0.8 μm and 12 μm, with a field-of-view as large as 450 μm. This microendoscope’s unprecedented capabilities are validated during label-free imaging, ex vivo on various fixed human tissue samples, and in vivo on an anesthetized mouse kidney demonstrating an imaging penetration depth greater than 300 μm below the surface of the organ. The results reported in this manuscript confirm that nonlinear microendoscopy can become a valuable clinical tool for real-time in situ assessment of pathological states. PMID:26673905

  12. Research on spatial coding compressive spectral imaging and its applicability for rural survey

    NASA Astrophysics Data System (ADS)

    Chen, Yuheng; Ji, Yiqun; Zhou, Jiankang; Chen, Xinhua; Shen, Weimin

    Compressive spectral imaging combines traditional spectral imaging method with new concept of compressive sensing thus has the advantages such as reducing acquisition data amount, realizing snapshot imaging for large field of view and increasing image signal-to-noise and its preliminary application effectiveness has been explored by early usage on the occasions such as high-speed imaging and fluorescent imaging. In this paper, the application potentiality for spatial coding compressive spectral imaging technique on rural survey is revealed. The physical model for spatial coding compressive spectral imaging is built on which its data flow procession is analyzed and its data reconstruction issue is concluded. The existing sparse reconstruction methods are reviewed thus specific module based on the two-step iterative shrinkage/thresholding algorithm is built so as to execute the imaging data reconstruction. The simulating imaging experiment based on AVIRIS visible band data of a specific selected rural scene is carried out. The spatial identification and spectral featuring extraction capacity for different ground species are evaluated by visual judgment of both single band image and spectral curve. The data fidelity evaluation parameters (RMSE and PSNR) are put forward so as to verify the data fidelity maintaining ability of this compressive imaging method quantitatively. The application potentiality of spatial coding compressive spectral imaging on rural survey, crop monitoring, vegetation inspection and further agricultural development demand is verified in this paper.

  13. First multiphoton tomography of brain in man

    NASA Astrophysics Data System (ADS)

    König, Karsten; Kantelhardt, Sven R.; Kalasauskas, Darius; Kim, Ella; Giese, Alf

    2016-03-01

    We report on the first two-photon in vivo brain tissue imaging study in man. High resolution in vivo histology by multiphoton tomography (MPT) including two-photon FLIM was performed in the operation theatre during neurosurgery to evaluate the feasibility to detect label-free tumor borders with subcellular resolution. This feasibility study demonstrates, that MPT has the potential to identify tumor borders on a cellular level in nearly real-time.

  14. Retinal Imaging of Infants on Spectral Domain Optical Coherence Tomography

    PubMed Central

    Vinekar, Anand; Mangalesh, Shwetha; Jayadev, Chaitra; Maldonado, Ramiro S.; Bauer, Noel; Toth, Cynthia A.

    2015-01-01

    Spectral domain coherence tomography (SD OCT) has become an important tool in the management of pediatric retinal diseases. It is a noncontact imaging device that provides detailed assessment of the microanatomy and pathology of the infant retina with a short acquisition time allowing office examination without the requirement of anesthesia. Our understanding of the development and maturation of the infant fovea has been enhanced by SD OCT allowing an in vivo assessment that correlates with histopathology. This has helped us understand the critical correlation of foveal development with visual potential in the first year of life and beyond. In this review, we summarize the recent literature on the clinical applications of SD OCT in studying the pathoanatomy of the infant macula, its ability to detect subclinical features, and its correlation with disease and vision. Retinopathy of prematurity and macular edema have been discussed in detail. The review also summarizes the current status of SD OCT in other infant retinal conditions, imaging the optic nerve, the choroid, and the retinal nerve fibre in infants and children, and suggests future areas of research. PMID:26221606

  15. Augmenting Forest Stand Parameters using Landsat TM Spectral Images

    NASA Astrophysics Data System (ADS)

    Reuveni, Y.; Dahan, E.; Anker, Y.; Sprintsin, M.

    2015-12-01

    Forest stand parameters, such as diameter at breast height (DBH), tree height (H), or volume per hectare (V), are imperative for forest resources assessment. Traditional inventory of forest stand parameters, usually based on fieldwork, is often difficult, time-consuming, and expensive, to conduct in large areas. Therefore, estimating forest stand parameters in large areas using traditional inventory approach augmented by satellites data has a significant implication for sustainable forest management and natural resources efficiency. However, obtaining suitable satellite image data for such purpose is a challenging task mainly because of insignificant knowledge between the forest stand parameters and satellite spectral response relationships. Here, we present the use of Landsat Thematic Mapper (TM) spectral responses data for augmenting forest stand parameter obtained from fieldwork at the Lahav Forest, in the Israeli Northern Negev. A new algorithm was developed in order to use all eight TM band when calculating the linear combination which correlates the most to each one of the forest stand parameters. Each linear combination is obtained first for local area inside the entire studied grid and is then fitted using a simple linear polynomial curve to the known forest stand parameter. Once the relationship between the two is characterized by a linear polynomial equation, the TM linear combination local area data is translated to the same equivalent area of the chosen forest stand parameter. At last, we interpolate the entire TM grid using a higher order polynomial fit applied to all the augmented local area combined together to attain full coverage of the desired forest stand parameter.

  16. Temporal and spectral imaging with micro-CT

    SciTech Connect

    Johnston, Samuel M.; Johnson, G. Allan; Badea, Cristian T.

    2012-08-15

    can be used to segment regions containing iodinated blood and compute measures of cardiac function. Conclusions: We believe this combined spectral and temporal imaging technique will be useful for future studies of cardiopulmonary disease in small animals.

  17. [Comparison among remotely sensed image fusion methods based on spectral response function].

    PubMed

    Dou, Wen; Sun, Hong-quan; Chen, Yun-hao

    2011-03-01

    Remotely sensed image fusion is a critical issue, and many methods have been developed to inject features from a high spatial resolution panchromatic sensor into low spatial resolution multi-spectral images, trying to preserve spectral signatures while improving spatial resolution of multi-spectral images. However, no explicit physical information of the detection system has been taken into account in usual methods, which might lead to undesirable effects such as severe spectral distortion. Benefiting from the proper decomposition of the image fusion problem by a concise image fusion mathematical model, the present paper focuses on comparing reasonable modulation coefficient of spatial details based on analysis of the spectral response function (SRF). According to the classification of former methods, three modulation coefficients based on SRF of sensors were concluded, which lead to three image fusion methods incorporating spatial detail retrieved by Gaussian high-pass filter. All these methods were validated on Ikonos data compared to GS and HPM method. PMID:21595232

  18. Spectral imaging as a potential tool for optical sentinel lymph node biopsies

    NASA Astrophysics Data System (ADS)

    O'Sullivan, Jack D.; Hoy, Paul R.; Rutt, Harvey N.

    2011-07-01

    Sentinel Lymph Node Biopsy (SLNB) is an increasingly standard procedure to help oncologists accurately stage cancers. It is performed as an alternative to full axillary lymph node dissection in breast cancer patients, reducing the risk of longterm health problems associated with lymph node removal. Intraoperative analysis is currently performed using touchprint cytology, which can introduce significant delay into the procedure. Spectral imaging is forming a multi-plane image where reflected intensities from a number of spectral bands are recorded at each pixel in the spatial plane. We investigate the possibility of using spectral imaging to assess sentinel lymph nodes of breast cancer patients with a view to eventually developing an optical technique that could significantly reduce the time required to perform this procedure. We investigate previously reported spectra of normal and metastatic tissue in the visible and near infrared region, using them as the basis of dummy spectral images. We analyse these images using the spectral angle map (SAM), a tool routinely used in other fields where spectral imaging is prevalent. We simulate random noise in these images in order to determine whether the SAM can discriminate between normal and metastatic pixels as the quality of the images deteriorates. We show that even in cases where noise levels are up to 20% of the maximum signal, the spectral angle map can distinguish healthy pixels from metastatic. We believe that this makes spectral imaging a good candidate for further study in the development of an optical SLNB.

  19. Multichannel tunable imager architecture for hyperspectral imaging in relevant spectral domains.

    PubMed

    Goenka, Chhavi; Semeter, Joshua; Noto, John; Baumgardner, Jeffrey; Riccobono, Juanita; Migliozzi, Mike; Dahlgren, Hanna; Marshall, Robert; Kapali, Sudha; Hirsch, Michael; Hampton, Donald; Akbari, Hassanali

    2016-04-20

    In this paper, we present a technique for dimensionality reduction in hyperspectral imaging during the data collection process. A four-channel hyperspectral imager using liquid crystal Fabry-Perot etalons has been built and used to verify this method for four applications: auroral imaging, plant study, landscape classification, and anomaly detection. This imager is capable of making measurements simultaneously in four wavelength ranges while being tunable within those ranges, and thus can be used to measure narrow contiguous bands in four spectral domains. In this paper, we describe the design, concept of operation, and deployment of this instrument. The results from preliminary testing of this instrument are discussed and are promising and demonstrate this instrument as a good candidate for hyperspectral imaging. PMID:27140081

  20. Optimization of a coded aperture coherent scatter spectral imaging system for medical imaging

    NASA Astrophysics Data System (ADS)

    Greenberg, Joel A.; Lakshmanan, Manu N.; Brady, David J.; Kapadia, Anuj J.

    2015-03-01

    Coherent scatter X-ray imaging is a technique that provides spatially-resolved information about the molecular structure of the material under investigation, yielding material-specific contrast that can aid medical diagnosis and inform treatment. In this study, we demonstrate a coherent-scatter imaging approach based on the use of coded apertures (known as coded aperture coherent scatter spectral imaging1, 2) that enables fast, dose-efficient, high-resolution scatter imaging of biologically-relevant materials. Specifically, we discuss how to optimize a coded aperture coherent scatter imaging system for a particular set of objects and materials, describe and characterize our experimental system, and use the system to demonstrate automated material detection in biological tissue.

  1. Fast Multispectral Imaging by Spatial Pixel-Binning and Spectral Unmixing.

    PubMed

    Pan, Zhi-Wei; Shen, Hui-Liang; Li, Chunguang; Chen, Shu-Jie; Xin, John H

    2016-08-01

    Multispectral imaging system is of wide application in relevant fields for its capability in acquiring spectral information of scenes. Its limitation is that, due to the large number of spectral channels, the imaging process can be quite time-consuming when capturing high-resolution (HR) multispectral images. To resolve this limitation, this paper proposes a fast multispectral imaging framework based on the image sensor pixel-binning and spectral unmixing techniques. The framework comprises a fast imaging stage and a computational reconstruction stage. In the imaging stage, only a few spectral images are acquired in HR, while most spectral images are acquired in low resolution (LR). The LR images are captured by applying pixel binning on the image sensor, such that the exposure time can be greatly reduced. In the reconstruction stage, an optimal number of basis spectra are computed and the signal-dependent noise statistics are estimated. Then the unknown HR images are efficiently reconstructed by solving a closed-form cost function that models the spatial and spectral degradations. The effectiveness of the proposed framework is evaluated using real-scene multispectral images. Experimental results validate that, in general, the method outperforms the state of the arts in terms of reconstruction accuracy, with additional 20× or more improvement in computational efficiency. PMID:27295668

  2. The Spectral Image Processing System (SIPS) - Interactive visualization and analysis of imaging spectrometer data

    NASA Technical Reports Server (NTRS)

    Kruse, F. A.; Lefkoff, A. B.; Boardman, J. W.; Heidebrecht, K. B.; Shapiro, A. T.; Barloon, P. J.; Goetz, A. F. H.

    1993-01-01

    The Center for the Study of Earth from Space (CSES) at the University of Colorado, Boulder, has developed a prototype interactive software system called the Spectral Image Processing System (SIPS) using IDL (the Interactive Data Language) on UNIX-based workstations. SIPS is designed to take advantage of the combination of high spectral resolution and spatial data presentation unique to imaging spectrometers. It streamlines analysis of these data by allowing scientists to rapidly interact with entire datasets. SIPS provides visualization tools for rapid exploratory analysis and numerical tools for quantitative modeling. The user interface is X-Windows-based, user friendly, and provides 'point and click' operation. SIPS is being used for multidisciplinary research concentrating on use of physically based analysis methods to enhance scientific results from imaging spectrometer data. The objective of this continuing effort is to develop operational techniques for quantitative analysis of imaging spectrometer data and to make them available to the scientific community prior to the launch of imaging spectrometer satellite systems such as the Earth Observing System (EOS) High Resolution Imaging Spectrometer (HIRIS).

  3. In vivo multiphoton tomography of skin cancer

    NASA Astrophysics Data System (ADS)

    König, Karsten; Riemann, Iris; Ehlers, Alexander; Buckle, Rainer; Dimitrow, Enrico; Kaatz, Martin; Fluhr, Joachim; Elsner, Peter

    2006-02-01

    The multiphoton tomograph DermaInspect was used to perform first clinical studies on the early non-invasive detection of skin cancer based on non-invasive optical sectioning of skin by two-photon autofluorescence and second harmonic generation. In particular, deep-tissue pigmented lesions -nevi- have been imaged with intracellular resolution using near infrared (NIR) femtosecond laser radiation. So far, more than 250 patients have been investigated. Cancerous tissues showed significant morphological differences compared to normal skin layers. In the case of malignant melanoma, the occurrence of luminescent melanocytes has been detected. Multiphoton tomography will become a novel non-invasive method to obtain high-resolution 3D optical biopsies for early cancer detection, treatment control, and in situ drug screening.

  4. Multi-photon Imaging of Tumor Cell Invasion in an Orthotopic Mouse Model of Oral Squamous Cell Carcinoma

    PubMed Central

    Gatesman Ammer, Amanda; Hayes, Karen E.; Martin, Karen H.; Zhang, Lingqing; Spirou, George A.; Weed, Scott A.

    2011-01-01

    Loco-regional invasion of head and neck cancer is linked to metastatic risk and presents a difficult challenge in designing and implementing patient management strategies. Orthotopic mouse models of oral cancer have been developed to facilitate the study of factors that impact invasion and serve as model system for evaluating anti-tumor therapeutics. In these systems, visualization of disseminated tumor cells within oral cavity tissues has typically been conducted by either conventional histology or with in vivo bioluminescent methods. A primary drawback of these techniques is the inherent inability to accurately visualize and quantify early tumor cell invasion arising from the primary site in three dimensions. Here we describe a protocol that combines an established model for squamous cell carcinoma of the tongue (SCOT) with two-photon imaging to allow multi-vectorial visualization of lingual tumor spread. The OSC-19 head and neck tumor cell line was stably engineered to express the F-actin binding peptide LifeAct fused to the mCherry fluorescent protein (LifeAct-mCherry). Fox1nu/nu mice injected with these cells reliably form tumors that allow the tongue to be visualized by ex-vivo application of two-photon microscopy. This technique allows for the orthotopic visualization of the tumor mass and locally invading cells in excised tongues without disruption of the regional tumor microenvironment. In addition, this system allows for the quantification of tumor cell invasion by calculating distances that invaded cells move from the primary tumor site. Overall this procedure provides an enhanced model system for analyzing factors that contribute to SCOT invasion and therapeutic treatments tailored to prevent local invasion and distant metastatic spread. This method also has the potential to be ultimately combined with other imaging modalities in an in vivo setting. PMID:21808230

  5. Research on the principle and experimentation of optical compressive spectral imaging

    NASA Astrophysics Data System (ADS)

    Chen, Yuheng; Chen, Xinhua; Zhou, Jiankang; Ji, Yiqun; Shen, Weimin

    2013-12-01

    The optical compressive spectral imaging method is a novel spectral imaging technique that draws in the inspiration of compressed sensing, which takes on the advantages such as reducing acquisition data amount, realizing snapshot imaging, increasing signal to noise ratio and so on. Considering the influence of the sampling quality on the ultimate imaging quality, researchers match the sampling interval with the modulation interval in former reported imaging system, while the depressed sampling rate leads to the loss on the original spectral resolution. To overcome that technical defect, the demand for the matching between the sampling interval and the modulation interval is disposed of and the spectral channel number of the designed experimental device increases more than threefold comparing to that of the previous method. Imaging experiment is carried out by use of the experiment installation and the spectral data cube of the shooting target is reconstructed with the acquired compressed image by use of the two-step iterative shrinkage/thresholding algorithms. The experimental result indicates that the spectral channel number increases effectively and the reconstructed data stays high-fidelity. The images and spectral curves are able to accurately reflect the spatial and spectral character of the target.

  6. Feature Transformation Detection Method with Best Spectral Band Selection Process for Hyper-spectral Imaging

    NASA Astrophysics Data System (ADS)

    Chen, Hai-Wen; McGurr, Mike; Brickhouse, Mark

    2015-11-01

    We present a newly developed feature transformation (FT) detection method for hyper-spectral imagery (HSI) sensors. In essence, the FT method, by transforming the original features (spectral bands) to a different feature domain, may considerably increase the statistical separation between the target and background probability density functions, and thus may significantly improve the target detection and identification performance, as evidenced by the test results in this paper. We show that by differentiating the original spectral, one can completely separate targets from the background using a single spectral band, leading to perfect detection results. In addition, we have proposed an automated best spectral band selection process with a double-threshold scheme that can rank the available spectral bands from the best to the worst for target detection. Finally, we have also proposed an automated cross-spectrum fusion process to further improve the detection performance in lower spectral range (<1000 nm) by selecting the best spectral band pair with multivariate analysis. Promising detection performance has been achieved using a small background material signature library for concept-proving, and has then been further evaluated and verified using a real background HSI scene collected by a HYDICE sensor.

  7. Forensic inspection of document using visible and near-infrared spectral imaging

    NASA Astrophysics Data System (ADS)

    Huang, Wei; Wang, Guiqiang; Xu, Xiaojing; Yu, Tao; Yang, Zhicheng

    2010-11-01

    In this study, the potential of visible and near-infrared spectral imaging as a technique of document inspection was examined. Doubtful documents are often found in economic cases, distinguished between original and added strokes and detected blurry characters are very useful for judgment. Burned, covered and rinsed documents in which the characters can't be identified with naked eyes were experimentally studied with a visible spectral imaging technique. Meanwhile, the same color inks were detected by both visible and near-infrared imaging spectrometers. Classification of spectral images was carried out in specialist spectral imaging software packager Misystem provided by Institute of Forensic Science. The technique significantly improved the detection of many documents, especially those that might be considered of poor quality or borderline characters. The visible spectral imaging was successful in detecting the burnt Chinese characters produced using pencils. It was possible to form spectral images showing the strokes even covered by Chinese ink by means of imaging at characteristic frequencies. As inks have very different spectral from the clothes, contribution and contrast of the rinsed lines and illegible seal words on clothes were clearly enhanced. By examining the spectral images from the inks, it was possible to determine whether the same color inks were written by the different pens. The results also show that the near-infrared spectrometer is better than visible one in distinguishing the same inks. In blind testing, spectral imaging was shown to achieve an average 85.1% chance of success. The results reveal the wide applications of spectral imaging in document evidence analysis. The potential of this technique in forensic science will be more apparent along with the further and deeper studies.

  8. Clenbuterol Assay by Spectral Imaging Surface Plasmon Resonance Biosensor System.

    PubMed

    Wu, Yichuan; Yao, Manwen; Fang, Xiangyi; Yang, Yucong; Cheng, Xiaoli

    2015-11-01

    To prevent illegal use of clenbuterol and for quality control in the food industry, more efficient and reliable methods for clenbuterol detection are needed. In this study, clenbuterol was detected using a spectral imaging surface plasmon resonance sensor system via two inhibition methods: (1) the target site compensation method, in which anti-clenbuterol antibody was immobilized on the sensor chip as a bioprobe and (2) the solution competition method in which a clenbuterol-BSA conjugate was immobilized on the sensor chip as the bioprobe. The detectable clenbuterol concentration ranged between 6.25 and 100 μg/mL for both methods. The clenbuterol limit of detection for the target site compensation method and solution competition method are estimated to be 6.7 and 4.5 μg/mL, respectively. The proposed methods were successfully applied to the detection of clenbuterol molecules and were found to have high specificity and high-throughput and were label free and operationally convenient. PMID:26319570

  9. Spectrally Selective Photocapacitance Modulation in Plasmonic Nanochannels for Infrared Imaging.

    PubMed

    Ho, Ya-Lun; Huang, Li-Chung; Delaunay, Jean-Jacques

    2016-05-11

    The optical response of subwavelength plasmonic structures can be used to monitor minute changes in their physical, chemical, and biological environments with high performance for sensing. The optical response in the far field is governed by the near-field properties of plasmon resonances. Sharp, tunable resonances can be obtained by controlling the shape of the structure and by using resonant cavities. However, microintegration of plasmonic structures on chips is difficult because of the readout in the far field. As such, structures that form an electrical microcircuit and directly monitor the near-field variation would be more desirable. Here, we report on an electronically readable photocapacitor based on a plasmonic nanochannel structure with high spectral resolution and a large modulation capability. The structure consists of metallic U-cavities and semiconductor channels, which are used to focus and confine light at the semiconductor-metal interfaces. At these interfaces, light is efficiently converted into photocarriers that change the electrical impedance of the structure. The capacitance modulation of the structure in response to light produces a light-to-dark contrast ratio larger than 10(3). A reflectance spectrum with a bandwidth of 16 nm and a 6% modulation depth is detected using a reactance variation of 3 kΩ with the same bandwidth. This photocapacitor design offers a practical means of monitoring changes induced by the near field and thus could be deployed in pixel arrays of image sensors for miniaturized spectroscopic applications. PMID:27120263

  10. Modeling spectrally varying resolution in broadband imaging systems

    NASA Astrophysics Data System (ADS)

    Cota, Stephen A.; Schnee, Scott L.; Loverro, Adam L.

    2015-09-01

    The remote sensing system engineering process often makes use of modeling and simulation tools to flow down specifications to subsystems and components, and/or to predict performance given a particular set of defined capabilities. A persistent question in the development and use of such tools is that of appropriate level of fidelity. In this paper we look at one problem area encountered in the simulation of panchromatic and other broadband imaging systems, that of accounting for spectrally varying resolution over the band. An established method for treating this variation is that of the polychromatic optical transfer function (OTF), but this technique imposes a measure of complexity on the simulation tool software architecture, as well as on users who must subsequently interact with it. We present a methodology for assessing the required level of fidelity for this problem and show that under some conditions it appears possible to forgo the polychromatic OTF formalism, or else to treat it with less than full rigor, with minimal loss in accuracy.

  11. Spectral analysis for evaluation of myocardial tracers for medical imaging

    SciTech Connect

    Huesman, Ronald H.; Reutter, Bryan W.; Marshall, Robert C.

    2000-10-11

    Kinetic analysis of dynamic tracer data is performed with the goal of evaluating myocardial radiotracers for cardiac nuclear medicine imaging. Data from experiments utilizing the isolated rabbit heart model are acquired by sampling the venous blood after introduction of a tracer of interest and a reference tracer. We have taken the approach that the kinetics are properly characterized by an impulse response function which describes the difference between the reference molecule (which does not leave the vasculature) and the molecule of interest which is transported across the capillary boundary and is made available to the cell. Using this formalism we can model the appearance of the tracer of interest in the venous output of the heart as a convolution of the appearance of the reference tracer with the impulse response. In this work we parameterize the impulse response function as the sum of a large number of exponential functions whose predetermined decay constants form a spectrum, and each is required only to have a nonnegative coefficient. This approach, called spectral analysis, has the advantage that it allows conventional compartmental analysis without prior knowledge of the number of compartments which the physiology may require or which the data will support.

  12. Wide-Field Imaging Interferometry Spatial-Spectral Image Synthesis Algorithms

    NASA Technical Reports Server (NTRS)

    Lyon, Richard G.; Leisawitz, David T.; Rinehart, Stephen A.; Memarsadeghi, Nargess; Sinukoff, Evan J.

    2012-01-01

    Developed is an algorithmic approach for wide field of view interferometric spatial-spectral image synthesis. The data collected from the interferometer consists of a set of double-Fourier image data cubes, one cube per baseline. These cubes are each three-dimensional consisting of arrays of two-dimensional detector counts versus delay line position. For each baseline a moving delay line allows collection of a large set of interferograms over the 2D wide field detector grid; one sampled interferogram per detector pixel per baseline. This aggregate set of interferograms, is algorithmically processed to construct a single spatial-spectral cube with angular resolution approaching the ratio of the wavelength to longest baseline. The wide field imaging is accomplished by insuring that the range of motion of the delay line encompasses the zero optical path difference fringe for each detector pixel in the desired field-of-view. Each baseline cube is incoherent relative to all other baseline cubes and thus has only phase information relative to itself. This lost phase information is recovered by having point, or otherwise known, sources within the field-of-view. The reference source phase is known and utilized as a constraint to recover the coherent phase relation between the baseline cubes and is key to the image synthesis. Described will be the mathematical formalism, with phase referencing and results will be shown using data collected from NASA/GSFC Wide-Field Imaging Interferometry Testbed (WIIT).

  13. Quantitative method to assess caries via fluorescence imaging from the perspective of autofluorescence spectral analysis

    NASA Astrophysics Data System (ADS)

    Chen, Q. G.; Zhu, H. H.; Xu, Y.; Lin, B.; Chen, H.

    2015-08-01

    A quantitative method to discriminate caries lesions for a fluorescence imaging system is proposed in this paper. The autofluorescence spectral investigation of 39 teeth samples classified by the International Caries Detection and Assessment System levels was performed at 405 nm excitation. The major differences in the different caries lesions focused on the relative spectral intensity range of 565-750 nm. The spectral parameter, defined as the ratio of wavebands at 565-750 nm to the whole spectral range, was calculated. The image component ratio R/(G + B) of color components was statistically computed by considering the spectral parameters (e.g. autofluorescence, optical filter, and spectral sensitivity) in our fluorescence color imaging system. Results showed that the spectral parameter and image component ratio presented a linear relation. Therefore, the image component ratio was graded as <0.66, 0.66-1.06, 1.06-1.62, and >1.62 to quantitatively classify sound, early decay, established decay, and severe decay tissues, respectively. Finally, the fluorescence images of caries were experimentally obtained, and the corresponding image component ratio distribution was compared with the classification result. A method to determine the numerical grades of caries using a fluorescence imaging system was proposed. This method can be applied to similar imaging systems.

  14. Short-wave infrared (SWIR) spectral imager based on Fabry-Perot interferometer for remote sensing

    NASA Astrophysics Data System (ADS)

    Mannila, Rami; Holmlund, Christer; Ojanen, Harri J.; Näsilä, Antti; Saari, Heikki

    2014-10-01

    VTT Technical Research Centre of Finland has developed a spectral imager for short-wave infrared (SWIR) wavelength range. The spectral imager is based on a tunable Fabry-Perot interferometer (FPI) accompanied by a commercial InGaAs Camera. The FPI consists of two dielectric coated mirrors separated by a tunable air gap. Tuning of the air gap tunes also transmitted wavelength and therefore FPI acts as a tunable band bass filter. The FPI is piezo-actuated and it uses three piezo-actuators in a closed capacitive feedback loop for air gap tuning. The FPI has multiple order transmission bands, which limit free spectral range. Therefore spectral imager contains two FPI in a stack, to make possible to cover spectral range of 1000 - 1700 nm. However, in the first tests imager was used with one FPI and spectral range was limited to 1100-1600 nm. The spectral resolution of the imager is approximately 15 nm (FWHM). Field of view (FOV) across the flight direction is 30 deg. Imaging resolution of the spectral imager is 256 x 320 pixels. The focal length of the optics is 12 mm and F-number is 3.2. This imager was tested in summer 2014 in an unmanned aerial vehicle (UAV) and therefore a size and a mass of the imager were critical. Total mass of the imager is approximately 1200 grams. In test campaign the spectral imager will be used for forest and agricultural imaging. In future, because results of the UAV test flights are promising, this technology can be applied to satellite applications also.

  15. [The hyperspectral camera side-scan geometric imaging in any direction considering the spectral mixing].

    PubMed

    Wang, Shu-Min; Zhang, Ai-Wu; Hu, Shao-Xing; Sun, Wei-Dong

    2014-07-01

    In order to correct the image distortion in the hyperspectral camera side-scan geometric Imaging, the image pixel geo-referenced algorithm was deduced in detail in the present paper, which is suitable to the linear push-broom camera side-scan imaging on the ground in any direction. It takes the orientation of objects in the navigation coordinates system into account. Combined with the ground sampling distance of geo-referenced image and the area of push broom imaging, the general process of geo-referenced image divided into grids is also presented. The new image rows and columns will be got through the geo-referenced image area dividing the ground sampling distance. Considering the error produced by round rule in the pixel grids generated progress, and the spectral mixing problem caused by traditional direct spectral sampling method in the process of image correction, the improved spectral sampling method based on the weighted fusion method was proposed. It takes the area proportion of adjacent pixels in the new generated pixel as coefficient and then the coefficients are normalized to avoid the spectral overflow. So the new generated pixel is combined with the geo-referenced adjacent pixels spectral. Finally the amounts of push-broom imaging experiments were taken on the ground, and the distortion images were corrected according to the algorithm proposed above. The results show that the linear image distortion correction algorithm is valid and robust. At the same time, multiple samples were selected in the corrected images to verify the spectral data. The results indicate that the improved spectral sampling method is better than the direct spectral sampling algorithm. It provides reference for the application of similar productions on the ground. PMID:25269321

  16. Spectral images browsing using principal component analysis and set partitioning in hierarchical tree

    NASA Astrophysics Data System (ADS)

    Ma, Long; Zhao, Deping

    2011-12-01

    Spectral imaging technology have been used mostly in remote sensing, but have recently been extended to new area requiring high fidelity color reproductions like telemedicine, e-commerce, etc. These spectral imaging systems are important because they offer improved color reproduction quality not only for a standard observer under a particular illuminantion, but for any other individual exhibiting normal color vision capability under another illuminantion. A possibility for browsing of the archives is needed. In this paper, the authors present a new spectral image browsing architecture. The architecture for browsing is expressed as follow: (1) The spectral domain of the spectral image is reduced with the PCA transform. As a result of the PCA transform the eigenvectors and the eigenimages are obtained. (2) We quantize the eigenimages with the original bit depth of spectral image (e.g. if spectral image is originally 8bit, then quantize eigenimage to 8bit), and use 32bit floating numbers for the eigenvectors. (3) The first eigenimage is lossless compressed by JPEG-LS, the other eigenimages were lossy compressed by wavelet based SPIHT algorithm. For experimental evalution, the following measures were used. We used PSNR as the measurement for spectral accuracy. And for the evaluation of color reproducibility, ΔE was used.here standard D65 was used as a light source. To test the proposed method, we used FOREST and CORAL spectral image databases contrain 12 and 10 spectral images, respectively. The images were acquired in the range of 403-696nm. The size of the images were 128*128, the number of bands was 40 and the resolution was 8 bits per sample. Our experiments show the proposed compression method is suitable for browsing, i.e., for visual purpose.

  17. High-resolution multimodal clinical multiphoton tomography of skin

    NASA Astrophysics Data System (ADS)

    König, Karsten

    2011-03-01

    This review focuses on multimodal multiphoton tomography based on near infrared femtosecond lasers. Clinical multiphoton tomographs for 3D high-resolution in vivo imaging have been placed into the market several years ago. The second generation of this Prism-Award winning High-Tech skin imaging tool (MPTflex) was introduced in 2010. The same year, the world's first clinical CARS studies have been performed with a hybrid multimodal multiphoton tomograph. In particular, non-fluorescent lipids and water as well as mitochondrial fluorescent NAD(P)H, fluorescent elastin, keratin, and melanin as well as SHG-active collagen has been imaged with submicron resolution in patients suffering from psoriasis. Further multimodal approaches include the combination of multiphoton tomographs with low-resolution wide-field systems such as ultrasound, optoacoustical, OCT, and dermoscopy systems. Multiphoton tomographs are currently employed in Australia, Japan, the US, and in several European countries for early diagnosis of skin cancer, optimization of treatment strategies, and cosmetic research including long-term testing of sunscreen nanoparticles as well as anti-aging products.

  18. Multi-photon excitation microscopy

    PubMed Central

    Diaspro, Alberto; Bianchini, Paolo; Vicidomini, Giuseppe; Faretta, Mario; Ramoino, Paola; Usai, Cesare

    2006-01-01

    Multi-photon excitation (MPE) microscopy plays a growing role among microscopical techniques utilized for studying biological matter. In conjunction with confocal microscopy it can be considered the imaging workhorse of life science laboratories. Its roots can be found in a fundamental work written by Maria Goeppert Mayer more than 70 years ago. Nowadays, 2PE and MPE microscopes are expected to increase their impact in areas such biotechnology, neurobiology, embryology, tissue engineering, materials science where imaging can be coupled to the possibility of using the microscopes in an active way, too. As well, 2PE implementations in noninvasive optical bioscopy or laser-based treatments point out to the relevance in clinical applications. Here we report about some basic aspects related to the phenomenon, implications in three-dimensional imaging microscopy, practical aspects related to design and realization of MPE microscopes, and we only give a list of potential applications and variations on the theme in order to offer a starting point for advancing new applications and developments. PMID:16756664

  19. Multi-photon excitation microscopy.

    PubMed

    Diaspro, Alberto; Bianchini, Paolo; Vicidomini, Giuseppe; Faretta, Mario; Ramoino, Paola; Usai, Cesare

    2006-01-01

    Multi-photon excitation (MPE) microscopy plays a growing role among microscopical techniques utilized for studying biological matter. In conjunction with confocal microscopy it can be considered the imaging workhorse of life science laboratories. Its roots can be found in a fundamental work written by Maria Goeppert Mayer more than 70 years ago. Nowadays, 2PE and MPE microscopes are expected to increase their impact in areas such biotechnology, neurobiology, embryology, tissue engineering, materials science where imaging can be coupled to the possibility of using the microscopes in an active way, too. As well, 2PE implementations in noninvasive optical bioscopy or laser-based treatments point out to the relevance in clinical applications. Here we report about some basic aspects related to the phenomenon, implications in three-dimensional imaging microscopy, practical aspects related to design and realization of MPE microscopes, and we only give a list of potential applications and variations on the theme in order to offer a starting point for advancing new applications and developments. PMID:16756664

  20. Analysis of the metabolic deterioration of ex vivo skin from ischemic necrosis through the imaging of intracellular NAD(P)H by multiphoton tomography and fluorescence lifetime imaging microscopy

    NASA Astrophysics Data System (ADS)

    Sanchez, Washington Y.; Prow, Tarl W.; Sanchez, Washington H.; Grice, Jeffrey E.; Roberts, Michael S.

    2010-07-01

    Ex vivo human skin has been used extensively for cosmeceutical and drug delivery studies, transplantable skin allografts, or skin flaps. However, it has a half-life of a few days due to ischemic necrosis. Traditional methods of assessing viability can be time-consuming and provide limited metabolic information. Using multiphoton tomography and fluorescence lifetime imaging (MPT-FLIM) we assess ischemic necrosis of ex vivo skin by NAD(P)H autofluorescence intensity and fluorescence lifetime. Ex vivo skin is stored in the presence and absence of nutrient media (Dulbecco Modified Eagle Medium) at -20, 4, and 37 °C and room temperature over a 7-day time course to establish different rates of metabolic deterioration. At higher temperatures we observe a decrease in NAD(P)H autofluorescence, higher image noise, and a significant increase in the average fluorescence lifetime (τm) from ~1000 to 2000 ps. Additionally, significant distortions in NAD(P)H fluorescence lifetime histograms correspond to the reduction in autofluorescence. Skin kept at 4 °C, with or without media, showed the least change. Our findings suggest that MPT-FLIM enables useful noninvasive optical biopsies to monitor the metabolic state and deterioration of human skin for research and clinical purposes.

  1. Optical design and system calibration for three-band spectral imaging system with interchangeable filters

    Technology Transfer Automated Retrieval System (TEKTRAN)

    The design and calibration of a three-band image acquisition system was reported. The prototype system developed in this research was a three-band spectral imaging system that acquired two visible (510 and 568 nm) images and a near-infrared (NIR) (800 nm) image simultaneously. The system was proto...

  2. Spectral imaging method for material classification and inspection of printed circuit boards

    NASA Astrophysics Data System (ADS)

    Ibrahim, Abdelhameed; Tominaga, Shoji; Horiuchi, Takahiko

    2010-05-01

    We propose a spectral imaging method for material classification and inspection of raw printed circuit boards (PCBs). The method is composed of two steps (1) estimation the PCB surface-spectral reflectances and (2) unsupervised classification of the reflectance data to make the inspection of PCB easy and efficient. First, we develop a spectral imaging system that captures high dynamic range images of a raw PCB with spatially and spectrally high resolutions in the region of visible wavelength. The surface-spectral reflectance is then estimated at every pixel point from multiple spectral images, based on the reflection characteristics of different materials. Second, the surface-spectral reflectance data are classified into several groups, according to the number of PCB materials. We develop an unsupervised classification algorithm incorporating both spectral information and spatial information, based on the Nyström approximation of the normalized cut method. The initial seeds for the Nyström procedure are effectively chosen using a guidance module based on the K-means algorithm. Low-dimensional spectral features are efficiently extracted from the original high-dimensional spectral reflectance data. The feasibility of the proposed method is examined in experiments using real PCBs in detail.

  3. The characteristic analysis of spectral image for cabbage leaves damaged by diamondback moth pests

    NASA Astrophysics Data System (ADS)

    Lin, Li-bo; Li, Hong-ning; Cao, Peng-fei; Qin, Feng; Yang, Shu-ming; Feng, Jie

    2015-02-01

    Cabbage growth and health diagnosis are important parts for cabbage fine planting, spectral imaging technology with the advantages of obtaining spectrum and space information of the target at the same time, which has become a research hotspot at home and abroad. The experiment measures the reflection spectrum at different stages using liquid crystal tunable filter (LCTF) and monochromatic CMOS camera composed of spectral imaging system for cabbage leaves damaged by diamondback moth pests, and analyzes its feature bands and the change of spectral parameters. The study shows that the feature bands of cabbage leaves damaged by diamondback moth pests have a tendency to blue light direction, the red edge towards blue shift, and red valley raising in spectral characteristic parameters, which have a good indication in diagnosing the extent of cabbage damaged by pests. Therefore, it has a unique advantage of monitoring the cabbage leaves damaged by diamondback moth pests by combinating feature bands and spectral characteristic parameters in spectral imaging technology.

  4. Laser-induced fluorescence imaging of subsurface tissue structures with a volume holographic spatial-spectral imaging system.

    PubMed

    Luo, Yuan; Gelsinger-Austin, Paul J; Watson, Jonathan M; Barbastathis, George; Barton, Jennifer K; Kostuk, Raymond K

    2008-09-15

    A three-dimensional imaging system incorporating multiplexed holographic gratings to visualize fluorescence tissue structures is presented. Holographic gratings formed in volume recording materials such as a phenanthrenquinone poly(methyl methacrylate) photopolymer have narrowband angular and spectral transmittance filtering properties that enable obtaining spatial-spectral information within an object. We demonstrate this imaging system's ability to obtain multiple depth-resolved fluorescence images simultaneously. PMID:18794943

  5. Design of multi-spectral images real-time segmentation system

    NASA Astrophysics Data System (ADS)

    Zhai, Bo; Qu, Youshan; Han, Yameng; Zhou, Jiang

    2015-02-01

    In order to realize the real-time segmentation processing of multi spectral images in practice, a real-time multi-spectral images segmentation system composed of four TMS320C6455 DSPs, two Virtex-4 - V4 XC4VLX80 - FPGAs and one Virtex-2 Pro - V2 Pro20 - FPGA is designed. Through the optimization of the cooperation processing of the multi DSP and multi FPGA, the parallel multitask processing ability of the DSPs and the effective interface coordination ability of the FPGAs in the built system are used fully. In order to display the processing ability, the segmentation test experiments of 10 spectra visible images, with 1024×1024, segmented by the Multi-scale Image Segmentation Method, was done in the built multi spectral images segment system. The experiment results prove that the multi DSP and multi FPGA multi spectral images processing system designed in this paper satisfies the real-time processing requirement in engineering practice.

  6. Fibre-coupled multiphoton microscope with adaptive motion compensation

    PubMed Central

    Sherlock, Ben; Warren, Sean; Stone, James; Neil, Mark; Paterson, Carl; Knight, Jonathan; French, Paul; Dunsby, Chris

    2015-01-01

    To address the challenge of sample motion during in vivo imaging, we present a fibre-coupled multiphoton microscope with active axial motion compensation. The position of the sample surface is measured using optical coherence tomography and fed back to a piezo actuator that adjusts the axial location of the objective to compensate for sample motion. We characterise the system’s performance and demonstrate that it can compensate for axial sample velocities up to 700 µm/s. Finally we illustrate the impact of motion compensation when imaging multiphoton excited autofluorescence in ex vivo mouse skin. PMID:26137387

  7. Multiphoton harvesting metal-organic frameworks

    NASA Astrophysics Data System (ADS)

    Quah, Hong Sheng; Chen, Weiqiang; Schreyer, Martin K.; Yang, Hui; Wong, Ming Wah; Ji, Wei; Vittal, Jagadese J.

    2015-08-01

    Multiphoton upconversion is a process where two or more photons are absorbed simultaneously to excite an electron to an excited state and, subsequently, the relaxation of electron gives rise to the emission of a photon with frequency greater than those of the absorbed photons. Materials possessing such property attracted attention due to applications in biological imaging, photodynamic therapy, three-dimensional optical data storage, frequency-upconverted lasing and optical power limiting. Here we report four-photon upconversion in metal-organic frameworks containing the ligand, trans, trans-9,10-bis(4-pyridylethenyl)anthracene. The ligand has a symmetrical acceptor-π-donor-π-acceptor structure and a singlet biradical electronic ground state, which boosted its multiphoton absorption cross-sections. We demonstrate that the upconversion efficiency can be enhanced by Förster resonance energy transfer within host-guest metal-organic frameworks consisting of encapsulated high quantum yielding guest molecules. Using these strategies, metal-organic framework materials, which can exhibit frequency-upconverted photoluminescence excited by simultaneous multiphoton absorption, can be rationally designed and synthesized.

  8. Multiphoton harvesting metal–organic frameworks

    PubMed Central

    Quah, Hong Sheng; Chen, Weiqiang; Schreyer, Martin K.; Yang, Hui; Wong, Ming Wah; Ji, Wei; Vittal, Jagadese J.

    2015-01-01

    Multiphoton upconversion is a process where two or more photons are absorbed simultaneously to excite an electron to an excited state and, subsequently, the relaxation of electron gives rise to the emission of a photon with frequency greater than those of the absorbed photons. Materials possessing such property attracted attention due to applications in biological imaging, photodynamic therapy, three-dimensional optical data storage, frequency-upconverted lasing and optical power limiting. Here we report four-photon upconversion in metal–organic frameworks containing the ligand, trans, trans-9,10-bis(4-pyridylethenyl)anthracene. The ligand has a symmetrical acceptor–π–donor–π–acceptor structure and a singlet biradical electronic ground state, which boosted its multiphoton absorption cross-sections. We demonstrate that the upconversion efficiency can be enhanced by Förster resonance energy transfer within host–guest metal–organic frameworks consisting of encapsulated high quantum yielding guest molecules. Using these strategies, metal–organic framework materials, which can exhibit frequency-upconverted photoluminescence excited by simultaneous multiphoton absorption, can be rationally designed and synthesized. PMID:26245741

  9. Seeing Beyond Sight: The Adaptive, Feature-Specific, Spectral Imaging Classifier

    NASA Astrophysics Data System (ADS)

    Dunlop-Gray, Matthew John

    Spectral imaging, a combination of spectroscopy and imaging, is a powerful tool for providing in situ material classification across a spatial scene. Typically spectral imaging analyses are interested in classification, though conventionally the classification is performed only after reconstruction of the spectral datacube, which can have upwards of 109 signal elements. In this dissertation, I present a computational spectral imaging system, the Adaptive Feature-Specific Spectral Imaging Classifier (AFSSI-C), which yields direct classification across the spatial scene without reconstruction of the source datacube. With a dual disperser architecture and a programmable spatial light modulator which induces spectral filtering, the AFSSI-C measures specific projections of the spectral datacube which in turn feed an adaptive Bayesian classification and feature design framework. I present my work related to the design, construction, and testing of this instrument, which ultimately demonstrated significantly improved classification accuracy compared to legacy spectral imaging systems by first showing agreement with simulation, and then comparing to expected performance of traditional systems. As a result of its open aperture and adaptive filters, the AFSSI-C achieves 250x better accuracy than pushbroom, whiskbroom, and tunable filter systems for a four-class problem at 0 dB TSNR (task signal-to-noise ratio)---a point where measurement noise is equal to the minimum separation between the library spectra. The AFSSI-C also achieves 100x better accuracy than random projections at 0 dB TSNR.

  10. Development and characterization of non-resonant multiphoton photoacoustic spectroscopy (NMPPAS) for brain tumor margining

    NASA Astrophysics Data System (ADS)

    Dahal, Sudhir

    ) and healthy tissue with over 99% accuracy. NMPPAS spectral features showed evident differences between tumor and healthy tissues, and ratiometric analysis ensured that only a few wavelengths could be used for excitation instead of using numerous wavelength excitations to create spectra. This process would significantly reduce the analysis time while maintaining the same degree of accuracy. Tissue phantoms were fabricated in order to characterize the properties of NMPPAS. Scattering particles were doped into the phantoms to simulate their light scattering properties to real tissues. This allowed for better control over shape, size, reproducibility and doping in the sample while maintaining the light-tissue interaction properties of real tissue. To make NMPPAS viable for clinical applications, the technique was characterized to determine the spatial (lateral and longitudinal) resolution, depth of penetration and its ability to image in three-dimension through layers of tissue. Both resolutions were determined to be near-cellular level resolution (50-70 microm), obtained initially with the aid of the technique of multiphoton fluorescence, and later verified using NMPPAS imaging. Additionally, the maximum depth of penetration and detection was determined to be about 1.4cm, making the technique extremely suitable to margin tumors from underlying tissues in the brain. The capability of NMPPAS to detect and image layers that lie beneath other structures and blood vessels was also investigated. Three-dimensional images were obtained for the first time using NMPPAS. The images were obtained from different depths and structures were imaged through other layers of existing structures in the sample. This verified that NMPPAS was capable of detecting and imaging structures that lie embedded within the tissues. NMPPAS images of embedded structures were also obtained with the presence of hemoglobin, which is potentially the largest source of background in blood-perfused tissues

  11. Spatial versus spectral compression ratio in compressive sensing of hyperspectral imaging

    NASA Astrophysics Data System (ADS)

    August, Yitzhak; Vachman, Chaim; Stern, Adrian

    2013-05-01

    Compressive hyperspectral imaging is based on the fact that hyperspectral data is highly redundant. However, there is no symmetry between the compressibility of the spatial and spectral domains, and that should be taken into account for optimal compressive hyperspectral imaging system design. Here we present a study of the influence of the ratio between the compression in the spatial and spectral domains on the performance of a 3D separable compressive hyperspectral imaging method we recently developed.

  12. Nonlinear dual-spectral image fusion for improving cone-beam-CT-based breast cancer diagnosis

    NASA Astrophysics Data System (ADS)

    Chen, Zikuan; Ning, Ruola; Conover, David; Willison, Kathleen

    2006-03-01

    Cone-beam breast computed tomography (CB Breast CT) can easily detect micro-calcifications and distinguish fat and glandular tissues from normal breast tissue. However, it may be a challenging task for CB Breast CT to distinguish benign from malignant tumors because of the subtle difference in x-ray attenuation. Due to the use of polyenergetic x-ray source, the x-ray and tissue interaction exhibits energy-dependent attenuation behavior, a phenomenon that, to date, has not been used for breast tissue characterization. We will exploit this spectral nature by equipping our CB Breast CT with dual-spectral imaging. The dual-spectral cone-beam scanning produces two spectral image datasets, from which we propose a nonlinear dual-spectral image fusion scheme to combine them into a single dataset, thereby incorporating the spectral information. In implementation, we will perform dual-spectral image fusion through a bi-variable polynomial that can be established by applying dual-spectral imaging to a reference material (with eight different thicknesses). From the fused dataset, we can reconstruct a volume, called a reference-equivalent volume or a fusion volume. By selecting the benign tissue as a reference material, we obtain a benign-equivalent volume. Likewise, we obtain a malignant-equivalent volume as well. In the pursuit of the discrimination of benign versus malignant tissues in a breast image, we perform intra-image as well as inter-image processing. The intra-image processing is an intensity transformation imposed only to a tomographic breast image itself, while the inter-image processing is exerted on two tomographic images extracted from two volumes. The nonlinear fusion scheme possesses these properties: 1) no noise magnification; 2) no feature dimensionality problem, and 3) drastic enhancement among specific features offered by nonlinear mapping. Its disadvantage lies in the possible misinterpretation resulting from nonlinear mapping.

  13. Compact static imaging spectrometer combining spectral zooming capability with a birefringent interferometer.

    PubMed

    Li, Jie; Zhu, Jingping; Qi, Chun; Zheng, Chuanlin; Gao, Bo; Zhang, Yunyao; Hou, Xun

    2013-04-22

    A compact static birefringent imaging spectrometer (BIS) with spectral zooming capability is presented. It based on two identical Wollaston prisms and has no slit. The most significant advantage of the BIS is that we can conveniently select spectral resolution to adapt to different application requirements and greatly reduce the size of the spectral image data for capturing, saving, transferring, and processing. Also, we show this configuration blend the advantage of a grating spectrometer and a Michelson interferometer: extremely compact, robust, wide free spectral range and very high throughput. PMID:23609723

  14. Modified tandem gratings anastigmatic imaging spectrometer with oblique incidence for spectral broadband

    NASA Astrophysics Data System (ADS)

    Cui, Chengguang; Wang, Shurong; Huang, Yu; Xue, Qingsheng; Li, Bo; Yu, Lei

    2015-09-01

    A modified spectrometer with tandem gratings that exhibits high spectral resolution and imaging quality for solar observation, monitoring, and understanding of coastal ocean processes is presented in this study. Spectral broadband anastigmatic imaging condition, spectral resolution, and initial optical structure are obtained based on geometric aberration theory. Compared with conventional tandem gratings spectrometers, this modified design permits flexibility in selecting gratings. A detailed discussion of the optical design and optical performance of an ultraviolet spectrometer with tandem gratings is also included to explain the advantage of oblique incidence for spectral broadband.

  15. Multimodal optoacoustic and multiphoton fluorescence microscopy

    NASA Astrophysics Data System (ADS)

    Sela, Gali; Razansky, Daniel; Shoham, Shy

    2013-03-01

    Multiphoton microscopy is a powerful imaging modality that enables structural and functional imaging with cellular and sub-cellular resolution, deep within biological tissues. Yet, its main contrast mechanism relies on extrinsically administered fluorescent indicators. Here we developed a system for simultaneous multimodal optoacoustic and multiphoton fluorescence 3D imaging, which attains both absorption and fluorescence-based contrast by integrating an ultrasonic transducer into a two-photon laser scanning microscope. The system is readily shown to enable acquisition of multimodal microscopic images of fluorescently labeled targets and cell cultures as well as intrinsic absorption-based images of pigmented biological tissue. During initial experiments, it was further observed that that detected optoacoustically-induced response contains low frequency signal variations, presumably due to cavitation-mediated signal generation by the high repetition rate (80MHz) near IR femtosecond laser. The multimodal system may provide complementary structural and functional information to the fluorescently labeled tissue, by superimposing optoacoustic images of intrinsic tissue chromophores, such as melanin deposits, pigmentation, and hemoglobin or other extrinsic particle or dye-based markers highly absorptive in the NIR spectrum.

  16. Dual-mode spectral imaging system employing a focus variable lens

    NASA Astrophysics Data System (ADS)

    Förster, Erik; Stürmer, Moritz; Wallrabe, Ulrike; Korvink, Jan; Bohnert, Patrick; Brunner, Robert

    2016-04-01

    This paper presents a dual-mode spectral imaging system, which allows switching between pure lateral imaging and the spectrally resolved recording of spatial information. The optical system was equipped with tunable functionalities in order to achieve high flexibility, cover a wide range of object distances, and address extended field angles. A fluidic membrane lens was used for the variable focus, and the recording of the laterally extended scene was made possible by successively adjusting the different tilting angles to the different object positions. The capability and performance of the spectral imaging system were assessed using various test scenes, with different aimed field positions and changing object distances.

  17. Initial clinical testing of a multi-spectral imaging system built on a smartphone platform

    NASA Astrophysics Data System (ADS)

    Mink, Jonah W.; Wexler, Shraga; Bolton, Frank J.; Hummel, Charles; Kahn, Bruce S.; Levitz, David

    2016-03-01

    Multi-spectral imaging systems are often expensive and bulky. An innovative multi-spectral imaging system was fitted onto a mobile colposcope, an imaging system built around a smartphone in order to image the uterine cervix from outside the body. The multi-spectral mobile colposcope (MSMC) acquires images at different wavelengths. This paper presents the clinical testing of MSMC imaging (technical validation of the MSMC system is described elsewhere 1 ). Patients who were referred to colposcopy following abnormal screening test (Pap or HPV DNA test) according to the standard of care were enrolled. Multi-spectral image sets of the cervix were acquired, consisting of images from the various wavelengths. Image acquisition took 1-2 sec. Areas suspected for dysplasia under white light imaging were biopsied, according to the standard of care. Biopsied sites were recorded on a clockface map of the cervix. Following the procedure, MSMC data was processed from the sites of biopsied sites. To date, the initial histopathological results are still outstanding. Qualitatively, structures in the cervical images were sharper at lower wavelengths than higher wavelengths. Patients tolerated imaging well. The result suggests MSMC holds promise for cervical imaging.

  18. Multi-spectral mid-infrared laser stand-off imaging

    NASA Astrophysics Data System (ADS)

    Wang, Yi; Wang, Yang; Le, Han Q.

    2005-08-01

    A multi-spectral mid-IR laser imaging study including system engineering, experiments, and image processing and analysis is described. A 4-λ scalable system was built with semiconductor lasers, covering from 3.3-9.6 μm. The X-Y scanning system was capable of 2-dimensional (2D) multi-spectral imaging at a stand-off distance from 13-40 m. The system was applied to diverse targets that consist of man-made and natural materials and objects, and shown capable to resolve and distinguish small spectral differences among the various targets. Colorless objects in the visible were shown with "colorful" signatures in the mid-IR. Image processing algorithm based on spectral contrast was shown most effective to exploit the laser sensitivity and accuracy, as opposed to algorithms that operate mainly on the image spatial intensity. The results also showed the complexity of laser imaging phenomenology, involving both spectroscopic and geometrical scattering effects. A demonstration of 3D multi-spectral imaging was also given. The system design is suitable for compact packages with semiconductor lasers, and the results suggest that laser-based multi-spectral imaging can be a unique and powerful technology for target discrimination.

  19. New confocal microscopy hyperspectral imager for NIR-emitting bioprobes: high spectral resolution for a wide spectral range (Conference Presentation)

    NASA Astrophysics Data System (ADS)

    Marcet, Stéphane; Benayas, Antonio; Quintanilla, Marta; Mangiarini, Francesca; Verhaegen, Marc; Vetrone, Fiorenzo; Blais-Ouellette, Sébastien

    2016-03-01

    Functional nanoscale materials are being extensively investigated for applications in biology and medicine and are ready to make significant contributions in the realization of exciting advancements in diverse areas of diagnostics and therapeutics. Aiming for more accurate, efficient, non-invasive and fast diagnostic tools, the use of near-infrared (NIR) light in the range of the 1st and 2nd biological window (NIR-I: 0.70-0.95 µm; NIR-II: 1.00-1.35 µm) provides deeper penetration depth into biological tissue, better image contrast, reduced phototoxicity and photobleaching. Consequently, NIR-based bioimaging became a quickly emerging field and manifold new NIR-emitting bioprobes have been reported. Since commercially available microscopes are not optimized for this kind of NPs, a new microscopy hyperspectral confocal imager has been developed to cover a broad spectral range (400 to 1700 nm) with high spectral resolution. The smallest spectral variation can be easily monitored thanks to the high spectral resolution (as low as 0.2 nm). This is possible thanks to a combination of an EMCCD and an InGaAs camera with a high resolution spectrometer. An extended number of NPs can be excited with a Ti:Sapphire laser, which provides tunable illumination within 690-1040 nm. Cells and tissues can be mapped in less than 100 ms, allowing in-vivo imaging. As a proof of concept, here we present the preliminary results of the spatial distribution of the fluorescence signal intensity from lanthanide doped nanoparticles incorporated into a system of biological interest. The temperature sub-mm gradient - analyzing the spectral features so gathered through an all-optical route is also thoroughly discussed.

  20. Tomographic Spectral Imaging with Multivariate Statistical Analysis: Comprehensive 3D Microanalysis.

    PubMed

    Kotula, Paul G; Keenan, Michael R; Michael, Joseph R

    2006-02-01

    A comprehensive three-dimensional (3D) microanalysis procedure using a combined scanning electron microscope (SEM)/focused ion beam (FIB) system equipped with an energy-dispersive X-ray spectrometer (EDS) has been developed. The FIB system was used first to prepare a site-specific region for X-ray microanalysis followed by the acquisition of an electron-beam generated X-ray spectral image. A small section of material was then removed by the FIB, followed by the acquisition of another X-ray spectral image. This serial sectioning procedure was repeated 10-12 times to sample a volume of material. The series of two-spatial-dimension spectral images were then concatenated into a single data set consisting of a series of volume elements or voxels each with an entire X-ray spectrum. This four-dimensional (three real space and one spectral dimension) spectral image was then comprehensively analyzed with Sandia's automated X-ray spectral image analysis software. This technique was applied to a simple Cu-Ag eutectic and a more complicated localized corrosion study where the powerful site-specific comprehensive analysis capability of tomographic spectral imaging (TSI) combined with multivariate statistical analysis is demonstrated. PMID:17481340

  1. Validation of spectral sky radiance derived from all-sky camera images - a case study

    NASA Astrophysics Data System (ADS)

    Tohsing, K.; Schrempf, M.; Riechelmann, S.; Seckmeyer, G.

    2014-07-01

    Spectral sky radiance (380-760 nm) is derived from measurements with a hemispherical sky imager (HSI) system. The HSI consists of a commercial compact CCD (charge coupled device) camera equipped with a fish-eye lens and provides hemispherical sky images in three reference bands such as red, green and blue. To obtain the spectral sky radiance from these images, non-linear regression functions for various sky conditions have been derived. The camera-based spectral sky radiance was validated using spectral sky radiance measured with a CCD spectroradiometer. The spectral sky radiance for complete distribution over the hemisphere between both instruments deviates by less than 20% at 500 nm for all sky conditions and for zenith angles less than 80°. The reconstructed spectra of the wavelengths 380-760 nm between both instruments at various directions deviate by less than 20% for all sky conditions.

  2. Validation of spectral sky radiance derived from all-sky camera images - a case study

    NASA Astrophysics Data System (ADS)

    Tohsing, K.; Schrempf, M.; Riechelmann, S.; Seckmeyer, G.

    2014-01-01

    Spectral sky radiance (380-760 nm) is derived from measurements with a Hemispherical Sky Imager (HSI) system. The HSI consists of a commercial compact CCD (charge coupled device) camera equipped with a fish-eye lens and provides hemispherical sky images in three reference bands such as red, green and blue. To obtain the spectral sky radiance from these images non-linear regression functions for various sky conditions have been derived. The camera-based spectral sky radiance was validated by spectral sky radiance measured with a CCD spectroradiometer. The spectral sky radiance for complete distribution over the hemisphere between both instruments deviates by less than 20% at 500 nm for all sky conditions and for zenith angles less than 80°. The reconstructed spectra of the wavelength 380 nm to 760 nm between both instruments at various directions deviate by less then 20% for all sky conditions.

  3. Picosecond spectral coherent anti-Stokes Raman scattering imaging with principal component analysis of meibomian glands

    NASA Astrophysics Data System (ADS)

    Lin, Chia-Yu; Suhalim, Jeffrey L.; Nien, Chyong Ly; Miljković, Miloš D.; Diem, Max; Jester, James V.; Potma, Eric. O.

    2011-02-01

    The lipid distribution in the mouse meibomian gland was examined with picosecond spectral anti-Stokes Raman scattering (CARS) imaging. Spectral CARS data sets were generated by imaging specific localized regions of the gland within tissue sections at consecutive Raman shifts in the CH2 stretching vibrational range. Spectral differences between the location specific CARS spectra obtained in the lipid-rich regions of the acinus and the central duct were observed, which were confirmed with a Raman microspectroscopic analysis, and attributed to meibum lipid modifications within the gland. A principal component analysis of the spectral data set reveals changes in the CARS spectrum when transitioning from the acini to the central duct. These results demonstrate the utility of picosecond spectral CARS imaging combined with multivariate analysis for assessing differences in the distribution and composition of lipids in tissues.

  4. Calculation of multiphoton ionization processes

    NASA Technical Reports Server (NTRS)

    Chang, T. N.; Poe, R. T.

    1976-01-01

    We propose an accurate and efficient procedure in the calculation of multiphoton ionization processes. In addition to the calculational advantage, this procedure also enables us to study the relative contributions of the resonant and nonresonant intermediate states.

  5. Multiphoton ionization of Uracil

    NASA Astrophysics Data System (ADS)

    Prieto, Eladio; Martinez, Denhi; Guerrero, Alfonso; Alvarez, Ignacio; Cisneros, Carmen

    2016-05-01

    Multiphoton ionization and dissociation of Uracil using a Reflectron time of flight spectrometer was performed along with radiation from the second harmonic of a Nd:YAG laser. Uracil is one of the four nitrogen bases that belong to RNA. The last years special interest has been concentrated on the study of the effects under UV radiation in nucleic acids1 and also in the role that this molecule could have played in the origin and development of life on our planet.2 The MPI mass spectra show that the presence and intensity of the resulting ions strongly depend on the density power. The identification of the ions in the mass spectra is presented. The results are compared with those obtained in other laboratories under different experimental conditions and some of them show partial agreement.3 The present work was supported by CONACYT-Mexico Grant 165410 and DGAPA UNAM Grant IN101215 and IN102613.

  6. Spectral angle mapper (SAM) based citrus greening disease detection using airborne hyperspectral imaging

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Over the past two decades, hyperspectral (HS) imaging has provided remarkable performance in ground object classification and disease identification, due to its high spectral resolution. In this paper, a novel method named “extended spectral angle mapping (ESAM)” is proposed to detect citrus greenin...

  7. Three-dimensional visualization of objects in scattering medium using integral imaging and spectral analysis

    NASA Astrophysics Data System (ADS)

    Lee, Yeonkyung; Yoo, Hoon

    2016-02-01

    This paper presents a three-dimensional visualization method of 3D objects in a scattering medium. The proposed method employs integral imaging and spectral analysis to improve the visual quality of 3D images. The images observed from 3D objects in the scattering medium such as turbid water suffer from image degradation due to scattering. The main reason is that the observed image signal is very weak compared with the scattering signal. Common image enhancement techniques including histogram equalization and contrast enhancement works improperly to overcome the problem. Thus, integral imaging that enables to integrate the weak signals from multiple images was discussed to improve image quality. In this paper, we apply spectral analysis to an integral imaging system such as the computational integral imaging reconstruction. Also, we introduce a signal model with a visibility parameter to analyze the scattering signal. The proposed method based on spectral analysis efficiently estimates the original signal and it is applied to elemental images. The visibility-enhanced elemental images are then used to reconstruct 3D images using a computational integral imaging reconstruction algorithm. To evaluate the proposed method, we perform the optical experiments for 3D objects in turbid water. The experimental results indicate that the proposed method outperforms the existing methods.

  8. Comparison of the Spectral Properties of Pansharpened Images Generated from AVNIR-2 and Prism Onboard Alos

    NASA Astrophysics Data System (ADS)

    Matsuoka, M.

    2012-07-01

    A considerable number of methods for pansharpening remote-sensing images have been developed to generate higher spatial resolution multispectral images by the fusion of lower resolution multispectral images and higher resolution panchromatic images. Because pansharpening alters the spectral properties of multispectral images, method selection is one of the key factors influencing the accuracy of subsequent analyses such as land-cover classification or change detection. In this study, seven pixel-based pansharpening methods (additive wavelet intensity, additive wavelet principal component, generalized Laplacian pyramid with spectral distortion minimization, generalized intensity-hue-saturation (GIHS) transform, GIHS adaptive, Gram-Schmidt spectral sharpening, and block-based synthetic variable ratio) were compared using AVNIR-2 and PRISM onboard ALOS from the viewpoint of the preservation of spectral properties of AVNIR-2. A visual comparison was made between pansharpened images generated from spatially degraded AVNIR-2 and original images over urban, agricultural, and forest areas. The similarity of the images was evaluated in terms of the image contrast, the color distinction, and the brightness of the ground objects. In the quantitative assessment, three kinds of statistical indices, correlation coefficient, ERGAS, and Q index, were calculated by band and land-cover type. These scores were relatively superior in bands 2 and 3 compared with the other two bands, especially over urban and agricultural areas. Band 4 showed a strong dependency on the land-cover type. This was attributable to the differences in the observing spectral wavelengths of the sensors and local scene variances.

  9. Intelligent spectral signature bio-imaging in vivo for surgical applications

    NASA Astrophysics Data System (ADS)

    Jeong, Jihoon; Frykman, Philip K.; Gaon, Mark; Chung, Alice P.; Lindsley, Erik H.; Hwang, Jae Y.; Farkas, Daniel L.

    2007-02-01

    Multi-spectral imaging provides digital images of a scene or object at a large, usually sequential number of wavelengths, generating precise optical spectra at every pixel. We use the term "spectral signature" for a quantitative plot of optical property variations as a function of wavelengths. We present here intelligent spectral signature bio-imaging methods we developed, including automatic signature selection based on machine learning algorithms and database search-based automatic color allocations, and selected visualization schemes matching these approaches. Using this intelligent spectral signature bio-imaging method, we could discriminate normal and aganglionic colon tissue of the Hirschsprung's disease mouse model with over 95% sensitivity and specificity in various similarity measure methods and various anatomic organs such as parathyroid gland, thyroid gland and pre-tracheal fat in dissected neck of the rat in vivo.

  10. RELIABILITY OF CONFOCAL MICROSCOPY SPECTRAL IMAGING SYSTEMS: USE OF MULTISPECTRAL BEADS

    EPA Science Inventory

    Background: There is a need for a standardized, impartial calibration, and validation protocol on confocal spectral imaging (CSI) microscope systems. To achieve this goal, it is necessary to have testing tools to provide a reproducible way to evaluate instrument performance. ...

  11. Multifocal multiphoton microscopy with adaptive optical correction

    NASA Astrophysics Data System (ADS)

    Coelho, Simao; Poland, Simon; Krstajic, Nikola; Li, David; Monypenny, James; Walker, Richard; Tyndall, David; Ng, Tony; Henderson, Robert; Ameer-Beg, Simon

    2013-02-01

    Fluorescence lifetime imaging microscopy (FLIM) is a well established approach for measuring dynamic signalling events inside living cells, including detection of protein-protein interactions. The improvement in optical penetration of infrared light compared with linear excitation due to Rayleigh scattering and low absorption have provided imaging depths of up to 1mm in brain tissue but significant image degradation occurs as samples distort (aberrate) the infrared excitation beam. Multiphoton time-correlated single photon counting (TCSPC) FLIM is a method for obtaining functional, high resolution images of biological structures. In order to achieve good statistical accuracy TCSPC typically requires long acquisition times. We report the development of a multifocal multiphoton microscope (MMM), titled MegaFLI. Beam parallelization performed via a 3D Gerchberg-Saxton (GS) algorithm using a Spatial Light Modulator (SLM), increases TCSPC count rate proportional to the number of beamlets produced. A weighted 3D GS algorithm is employed to improve homogeneity. An added benefit is the implementation of flexible and adaptive optical correction. Adaptive optics performed by means of Zernike polynomials are used to correct for system induced aberrations. Here we present results with significant improvement in throughput obtained using a novel complementary metal-oxide-semiconductor (CMOS) 1024 pixel single-photon avalanche diode (SPAD) array, opening the way to truly high-throughput FLIM.

  12. Detection of blood oxygen level by noninvasive passive spectral imaging of skin

    NASA Astrophysics Data System (ADS)

    Gupta, Neelam; Ramella-Roman, Jessica C.

    2008-02-01

    A compact optical hyperspectral imager that can detect both spectral and polarization signatures was used for passive noninvasive imaging of human skin. This vibration-insensitive imager uses an acousto-optic tunable filter (AOTF) as a spectral selection element and an electronically tunable liquid crystal variable retarder (LCVR) as a polarization device. Such an imager is ideally suited to provide both agile spectral and polarization signatures and can be readily used for real time in vivo medical imaging applications. Operation of this imager and image acquisition is fully computer controlled. This imager covers visible to near-infrared (VNIR) region from 400 to 800 nm with a 10 nm spectral resolution at 600 nm and uses a TeO II AOTF with a 15×15 mm2 linear aperture and a 4.2° angular aperture. At each wavelength 640×480 images with two orthogonal polarization are captured and a total of 41 spectral images are collected to form an image cube. A commercial Si CCD camera was used along with off-the-shelf lenses, mirrors and irises. We carried out experiments with a human subject and controlled the blood perfusion in the individual arm and finger by using a pressure cuff and a rubber band, respectively. Images were captured by illuminating the subject with a white light lamp source and imaging it from a distance. When the hyperspectral image analysis was performed we could observe the effects of skin deoxygenation. In this paper we will described our instrument, the experimental setup, the images obtained and the analysis results.

  13. Optical imaging of hemoglobin oxygen saturation using a small number of spectral images for endoscopic application.

    PubMed

    Saito, Takaaki; Yamaguchi, Hiroshi

    2015-12-01

    Tissue hypoxia is associated with tumor and inflammatory diseases, and detection of hypoxia is potentially useful for their detailed diagnosis. An endoscope system that can optically observe hemoglobin oxygen saturation (StO2) would enable minimally invasive, real-time detection of lesion hypoxia in vivo. Currently, point measurement of tissue StO2 via endoscopy is possible using the commercial fiber-optic oximeter T-Stat, which is based on visible light spectroscopy at many wavelengths. For clinical use, however, imaging of StO2 is desirable to assess the distribution of tissue oxygenation around a lesion. Here, we describe our StO2 imaging technique based on a small number of wavelength ranges in the visible range. By assuming a homogeneous tissue, we demonstrated that tissue StO2 can be obtained independently from the scattering property and blood concentration of tissue using four spectral bands. We developed a prototype endoscope system and used it to observe tissue-simulating phantoms. The StO2 (%) values obtained using our technique agreed with those from the T-Stat within 10%. We also showed that tissue StO2 can be derived using three spectral band if the scattering property is fixed at preliminarily measured values. PMID:26720878

  14. Optical imaging of hemoglobin oxygen saturation using a small number of spectral images for endoscopic application

    NASA Astrophysics Data System (ADS)

    Saito, Takaaki; Yamaguchi, Hiroshi

    2015-12-01

    Tissue hypoxia is associated with tumor and inflammatory diseases, and detection of hypoxia is potentially useful for their detailed diagnosis. An endoscope system that can optically observe hemoglobin oxygen saturation (StO2) would enable minimally invasive, real-time detection of lesion hypoxia in vivo. Currently, point measurement of tissue StO2 via endoscopy is possible using the commercial fiber-optic oximeter T-Stat, which is based on visible light spectroscopy at many wavelengths. For clinical use, however, imaging of StO2 is desirable to assess the distribution of tissue oxygenation around a lesion. Here, we describe our StO2 imaging technique based on a small number of wavelength ranges in the visible range. By assuming a homogeneous tissue, we demonstrated that tissue StO2 can be obtained independently from the scattering property and blood concentration of tissue using four spectral bands. We developed a prototype endoscope system and used it to observe tissue-simulating phantoms. The StO2 (%) values obtained using our technique agreed with those from the T-Stat within 10%. We also showed that tissue StO2 can be derived using three spectral band if the scattering property is fixed at preliminarily measured values.

  15. Comparison of Spectral and Image Morphological Analysis for Egg Early Hatching Property Detection Based on Hyperspectral Imaging

    PubMed Central

    Zhang, Wei; Pan, Leiqing; Tu, Kang; Zhang, Qiang; Liu, Ming

    2014-01-01

    The use of non-destructive methods to detect egg hatching properties could increase efficiency in commercial hatcheries by saving space, reducing costs, and ensuring hatching quality. For this purpose, a hyperspectral imaging system was built to detect embryo development and vitality using spectral and morphological information of hatching eggs. A total of 150 green shell eggs were used, and hyperspectral images were collected for every egg on day 0, 1, 2, 3 and 4 of incubation. After imaging, two analysis methods were developed to extract egg hatching characteristic. Firstly, hyperspectral images of samples were evaluated using Principal Component Analysis (PCA) and only one optimal band with 822 nm was selected for extracting spectral characteristics of hatching egg. Secondly, an image segmentation algorithm was applied to isolate the image morphologic characteristics of hatching egg. To investigate the applicability of spectral and image morphological analysis for detecting egg early hatching properties, Learning Vector Quantization neural network (LVQNN) was employed. The experimental results demonstrated that model using image morphological characteristics could achieve better accuracy and generalization than using spectral characteristic parameters, and the discrimination accuracy for eggs with embryo development were 97% at day 3, 100% at day 4. In addition, the recognition results for eggs with weak embryo development reached 81% at day 3, and 92% at day 4. This study suggested that image morphological analysis was a novel application of hyperspectral imaging technology to detect egg early hatching properties. PMID:24551130

  16. Implementation of a multi-spectral color imaging device without color filter array

    NASA Astrophysics Data System (ADS)

    Langfelder, G.; Longoni, A. F.; Zaraga, F.

    2011-01-01

    In this work the use of the Transverse Field Detector (TFD) as a device for multispectral image acquisition is proposed. The TFD is a color imaging pixel capable of color reconstruction without color filters. Its basic working principle is based on the generation of a suitable electric field configuration inside a Silicon depleted region by means of biasing voltages applied to surface contacts. With respect to previously proposed methods for performing multispectral capture, the TFD has a unique characteristic of electrically tunable spectral responses. This feature allows capturing an image with different sets of spectral responses (RGB, R'G'B', and so on) simply by tuning the device biasing voltages in multiple captures. In this way no hardware complexity (no external filter wheels or varying sources) is added with respect to a colorimetric device. The estimation of the spectral reflectance of the area imaged by a TFD pixel is based in this work on a linear combination of six eigenfunctions. It is shown that a spectral reconstruction can be obtained either (1) using two subsequent image captures that generate six TFD spectral responses or (2) using a new asymmetric biasing scheme, which allows the implementation of five spectral responses for each TFD pixel site in a single configuration, definitely allowing one-shot multispectral imaging.

  17. On combining spectral and spatial information of hyperspectral image for camouflaged target detecting

    NASA Astrophysics Data System (ADS)

    Hua, Wenshen; Liu, Xun; Yang, Jia

    2013-12-01

    Detecting enemy's targets and being undetectable play increasingly important roles in modern warfare. Hyperspectral images can provide large spectral range and high spectral resolution, which are invaluable in discriminating between camouflaged targets and backgrounds. As supervised classification requires prior knowledge which cannot be acquired easily, unsupervised classification usually is adopted to process hyperspectral images to detect camouflaged target. But one of its drawbacks—low detecting accuracy confines its application for camouflaged target detecting. Most research on the processing of hyperspectral image tends to focus exclusively on spectral domain and ignores spatial domain. However current hyperspectral image provides high spatial resolution which contains useful information for camouflaged target detecting. A new method combining spectral and spatial information is proposed to increase the detecting accuracy using unsupervised classification. The method has two steps. In the first step, a traditional unsupervised classifier (i.e. K-MEANS, ISODATA) is adopted to classify the hyperspectral image to acquire basic classifications or clusters. During the second step, a 3×3 model and spectral angle mapping are utilized to test the spatial character of the hyperspectral image. The spatial character is defined as spatial homogeneity and calculated by spectral angle mapping. Theory analysis and experiment shows the method is reasonable and efficient. Camouflaged targets are extracted from the background and different camouflaged targets are also recognized. And the proposed algorithm outperforms K-MEANS in terms of detecting accuracy, robustness and edge's distinction. This paper demonstrates the new method is meaningful to camouflaged targets detecting.

  18. Comparison of objective lenses for multiphoton microscopy in turbid samples.

    PubMed

    Singh, Avtar; McMullen, Jesse D; Doris, Eli A; Zipfel, Warren R

    2015-08-01

    Optimization of illumination and detection optics is pivotal for multiphoton imaging in highly scattering tissue and the objective lens is the central component in both of these pathways. To better understand how basic lens parameters (NA, magnification, field number) affect fluorescence collection and image quality, a two-detector setup was used with a specialized sample cell to separate measurement of total excitation from epifluorescence collection. Our data corroborate earlier findings that low-mag lenses can be superior at collecting scattered photons, and we compare a set of commonly used multiphoton objective lenses in terms of their ability to collect scattered fluorescence, providing guidance for the design of multiphoton imaging systems. For example, our measurements of epi-fluorescence beam divergence in the presence of scattering reveal minimal beam broadening, indicating that often-advocated over-sized collection optics are not as advantageous as previously thought. These experiments also provide a framework for choosing objective lenses for multiphoton imaging by relating the results of our measurements to various design parameters of the objectives lenses used. PMID:26309771

  19. Subsurface imaging using the spectral polarization difference technique and NIR illumination

    SciTech Connect

    Alfano, R R; Demos, S G; Radousky, H B

    1999-01-26

    A subsurface imaging system is utilized to test the ability of the spectral polarization difference imaging technique for deep subsurface imaging in tissues. The illumination of the system is derived from compact class III lasers in the red and NIR spectral region and, alternatively, from a white light source and selection of the appropriate illumination wavelength using band-pass optical filters. The experimental results demonstrate detection and imaging of a high-scattering object located up to 1.5 cm underneath the surface of a host chicken tissue.

  20. Analysis of computed tomographic imaging spectrometers. I. Spatial and spectral resolution.

    PubMed

    Hagen, Nathan; Dereniak, Eustace L

    2008-10-01

    Computed tomographic imaging spectrometers measure the spectrally resolved image of an object scene in an entirely different manner from traditional whisk-broom or push-broom systems, and thus their noise behavior and data artifacts are unfamiliar. We review computed tomographic imaging spectrometry (CTIS) measurement systems and analyze their performance, with the aim of providing a vocabulary for discussing resolution in CTIS instruments, by illustrating the artifacts present in their reconstructed data and contributing a rule-of-thumb measure of their spectral resolution. We also show how the data reconstruction speed can be improved, at no cost in reconstruction quality, by ignoring redundant projections within the measured raw images. PMID:18830288

  1. Spectral feature variations in x-ray diffraction imaging systems

    NASA Astrophysics Data System (ADS)

    Wolter, Scott D.; Greenberg, Joel A.

    2016-05-01

    Materials with different atomic or molecular structures give rise to unique scatter spectra when measured by X-ray diffraction. The details of these spectra, though, can vary based on both intrinsic (e.g., degree of crystallinity or doping) and extrinsic (e.g., pressure or temperature) conditions. While this sensitivity is useful for detailed characterizations of the material properties, these dependences make it difficult to perform more general classification tasks, such as explosives threat detection in aviation security. A number of challenges, therefore, currently exist for reliable substance detection including the similarity in spectral features among some categories of materials combined with spectral feature variations from materials processing and environmental factors. These factors complicate the creation of a material dictionary and the implementation of conventional classification and detection algorithms. Herein, we report on two prominent factors that lead to variations in spectral features: crystalline texture and temperature variations. Spectral feature comparisons between materials categories will be described for solid metallic sheet, aqueous liquids, polymer sheet, and metallic, organic, and inorganic powder specimens. While liquids are largely immune to texture effects, they are susceptible to temperature changes that can modify their density or produce phase changes. We will describe in situ temperature-dependent measurement of aqueous-based commercial goods in the temperature range of -20°C to 35°C.

  2. Low cost laser system generating 26-fs pulse duration, 30-kW peak power, and tunability from 800 to 1200 nm for multiphoton microscopy

    NASA Astrophysics Data System (ADS)

    Resan, Bojan; Brunner, Felix; Rohrbacher, Andreas; Ammann, Hubert; Weingarten, Kurt J.

    2012-03-01

    We demonstrate a novel low-cost, low-noise, tunable, high-peak-power, ultrafast laser system based on a SESAMmodelocked, solid-state Yb tungstate laser plus spectral broadening via a microstructured fiber followed by pulse compression. The spectral selection, tuning, and pulse compression are performed with a simple prism compressor. The spectral broadening and fiber parameters are chosen to insure low-noise and short pulse operation of the tunable output. The long-term stable output pulses are tunable from 800 to 1200 nm, with a peak power up to 30 kW and pulse duration down to 26 fs. We demonstrate the generation of an output beam with 30 fs pulsewidth and multiple colors in infrared. In particular, we compressed selected spectral slices centered at 960 and 1100 nm suitable for imaging with green fluorescent protein and red dyes. Such a multicolor, 30 fs laser is ideally suited for simultaneous multispectral multiphoton imaging. This system is attractive for variety of applications including multiphoton (TPE, SHG, THG, CARS) and multimodal microscopy, nanosurgery, and optical coherence tomography (OCT). Such system is simpler, lower-cost, and much easier to use (fully turn-key) compared to a currently available solutions for near-infrared ultrashort pulses, typically a Ti:sapphire laser-pumped OPO.

  3. Model-based restoration of underwater spectral images captured with narrowband filters.

    PubMed

    Guo, Yilu; Song, Hong; Liu, Hongbo; Wei, He; Yang, Ping; Zhan, Shuyue; Wang, Hangzhou; Huang, Hui; Liao, Ningfang; Mu, Quanquan; Leng, Jianxing; Yang, Wenjing

    2016-06-13

    Underwater spectral imaging is a promising method for mapping, classification and health monitoring of coral reefs and seafloor inhabitants. However, the spectrum of light is distorted during the underwater imaging process due to wavelength-dependent attenuation by the water. This paper presents a model-based method that accurately restores brightness of underwater spectral images captured with narrowband filters. A model is built for narrowband underwater spectral imaging. The model structure is derived from physical principles, representing the absorption, scattering and refraction by water and the optical properties of narrowband filters, lenses and image sensors. The model coefficients are calibrated based on spectral images captured underwater and in air. With the imaging model available, energy loss due to water attenuation is restored for images captured at different underwater distances. An experimental setup is built and experiments are carried out to verify the proposed method. Underwater images captured within an underwater distance of 260 cm are restored and compared with those in air. Results show that the relative restoration error is 3.58% on average for the test images, thus proving the accuracy of the proposed method. PMID:27410329

  4. Stimulated Raman hyperspectral imaging based on spectral filtering of broadband fiber laser pulses.

    PubMed

    Ozeki, Yasuyuki; Umemura, Wataru; Sumimura, Kazuhiko; Nishizawa, Norihiko; Fukui, Kiichi; Itoh, Kazuyoshi

    2012-02-01

    We demonstrate a technique of hyperspectral imaging in stimulated Raman scattering (SRS) microscopy using a tunable optical filter, whose transmission wavelength can be varied quickly by a galvanometer mirror. Experimentally, broadband Yb fiber laser pulses are synchronized with picosecond Ti:sapphire pulses, and then spectrally filtered out by the filter. After amplification by fiber amplifiers, we obtain narrowband pulses with a spectral width of <3.3 cm(-1) and a wavelength tunability of >225 cm(-1). By using these pulses, we accomplish SRS imaging of polymer beads with spectral information. PMID:22297376

  5. Spectral compression algorithms for the analysis of very large multivariate images

    DOEpatents

    Keenan, Michael R.

    2007-10-16

    A method for spectrally compressing data sets enables the efficient analysis of very large multivariate images. The spectral compression algorithm uses a factored representation of the data that can be obtained from Principal Components Analysis or other factorization technique. Furthermore, a block algorithm can be used for performing common operations more efficiently. An image analysis can be performed on the factored representation of the data, using only the most significant factors. The spectral compression algorithm can be combined with a spatial compression algorithm to provide further computational efficiencies.

  6. High-sensitive and broad-dynamic-range quantitative phase imaging with spectral domain phase microscopy.

    PubMed

    Yan, Yangzhi; Ding, Zhihua; Shen, Yi; Chen, Zhiyan; Zhao, Chen; Ni, Yang

    2013-11-01

    Spectral domain phase microscopy for high-sensitive and broad-dynamic-range quantitative phase imaging is presented. The phase retrieval is realized in the depth domain to maintain a high sensitivity, while the phase information obtained in the spectral domain is exploited to extend the dynamic range of optical path difference. Sensitivity advantage of phase retrieved in the depth domain over that in the spectral domain is thoroughly investigated. The performance of the proposed depth domain phase based approach is illustrated by phase imaging of a resolution target and an onion skin. PMID:24216799

  7. Visible spectral imager for occultation and nightglow (VISION) for the PICASSO Mission

    NASA Astrophysics Data System (ADS)

    Saari, Heikki; Näsilä, Antti; Holmlund, Christer; Mannila, Rami; Näkki, Ismo; Ojanen, Harri J.; Fussen, Didier; Pieroux, Didier; Demoulin, Philippe; Dekemper, Emmanuel; Vanhellemont, Filip

    2015-10-01

    PICASSO - A PICo-satellite for Atmospheric and Space Science Observations is an ESA project led by the Belgian Institute for Space Aeronomy, in collaboration with VTT, Clyde Space Ltd. (UK), and the Centre Spatial de Liège (BE). VTT Technical Research Centre of Finland Ltd. will deliver the Visible Spectral Imager for Occultation and Nightglow (VISION) for the PICASSO mission. The VISION targets primarily the observation of the Earth's atmospheric limb during orbital Sun occultation. By assessing the radiation absorption in the Chappuis band for different tangent altitudes, the vertical profile of the ozone is retrieved. A secondary objective is to measure the deformation of the solar disk so that stratospheric and mesospheric temperature profiles are retrieved by inversion of the refractive raytracing problem. Finally, occasional full spectral observations of polar auroras are also foreseen. The VISION design realized with commercial of the shelf (CoTS) parts is described. The VISION instrument is small, lightweight (~500 g), Piezo-actuated Fabry-Perot Interferometer (PFPI) tunable spectral imager operating in the visible and near-infrared (430 - 800 nm). The spectral resolution over the whole wavelength range will be better than 10 nm @ FWHM. VISION has is 2.5° x 2.5° total field of view and it delivers maximum 2048 x 2048 pixel spectral images. The sun image size is around 0.5° i.e. ~500 pixels. To enable fast spectral data image acquisition VISION can be operated with programmable image sizes. VTT has previously developed PFPI tunable filter based AaSI Spectral Imager for the Aalto-1 Finnish CubeSat. In VISION the requirements of the spectral resolution and stability are tighter than in AaSI. Therefore the optimization of the of the PFPI gap control loop for the operating temperature range and vacuum conditions has to be improved. VISION optical, mechanical and electrical design is described.

  8. IR spectral imaging for histopathological characterization of xenografted human colon carcinomas.

    PubMed

    Wolthuis, Rolf; Travo, Adrian; Nicolet, Céline; Neuville, Agnès; Gaub, Marie-Pierre; Guenot, Dominique; Ly, Elodie; Manfait, Michel; Jeannesson, Pierre; Piot, Olivier

    2008-11-15

    This study aims to develop IR imaging of tumor tissues for generating an automated IR-based histology. Formalin-fixed paraffin-embedded xenografts of human colon carcinomas were analyzed. Chemometric and statistical multivariate treatments of spectral data permitted to probe the intrinsic chemical composition of tissues, directly from paraffinized sections without previous dewaxing. Reconstructed color-coded spectral images revealed a marked tumor heterogeneity. We identified three spectral clusters associated to tumoral tissues, whereas HE staining revealed only a single structure. Nine other clusters were assigned to either necrotic or host tissues. This spectral histology proved to be consistent over multiple passages of the same xenografted tumor confirming that intratumoral heterogeneity was maintained over time. In addition, developing an innovative image analysis, based on the quantification of neighboring pixels, permitted the identification of two main sequences of spectral clusters related to the tissue spatial organization. Molecular attribution of the spectral differences between the tumor clusters revealed differences of transcriptional activity within these tumor tissue subtypes. In conclusion, IR spectral imaging proves to be highly effective both for reproducible tissue subtype recognition and for tumor heterogeneity characterization. This may represent an attractive tool for routine high throughput diagnostic challenges, independent from visual morphology. PMID:18847281

  9. Real-time detection of natural objects using AM-coded spectral matching imager

    NASA Astrophysics Data System (ADS)

    Kimachi, Akira

    2004-12-01

    This paper describes application of the amplitude-modulation (AM)-coded spectral matching imager (SMI) to real-time detection of natural objects such as human beings, animals, vegetables, or geological objects or phenomena, which are much more liable to change with time than artificial products while often exhibiting characteristic spectral functions associated with some specific activity states. The AM-SMI produces correlation between spectral functions of the object and a reference at each pixel of the correlation image sensor (CIS) in every frame, based on orthogonal amplitude modulation (AM) of each spectral channel and simultaneous demodulation of all channels on the CIS. This principle makes the SMI suitable to monitoring dynamic behavior of natural objects in real-time by looking at a particular spectral reflectance or transmittance function. A twelve-channel multispectral light source was developed with improved spatial uniformity of spectral irradiance compared to a previous one. Experimental results of spectral matching imaging of human skin and vegetable leaves are demonstrated, as well as a preliminary feasibility test of imaging a reflective object using a test color chart.

  10. Real-time detection of natural objects using AM-coded spectral matching imager

    NASA Astrophysics Data System (ADS)

    Kimachi, Akira

    2005-01-01

    This paper describes application of the amplitude-modulation (AM)-coded spectral matching imager (SMI) to real-time detection of natural objects such as human beings, animals, vegetables, or geological objects or phenomena, which are much more liable to change with time than artificial products while often exhibiting characteristic spectral functions associated with some specific activity states. The AM-SMI produces correlation between spectral functions of the object and a reference at each pixel of the correlation image sensor (CIS) in every frame, based on orthogonal amplitude modulation (AM) of each spectral channel and simultaneous demodulation of all channels on the CIS. This principle makes the SMI suitable to monitoring dynamic behavior of natural objects in real-time by looking at a particular spectral reflectance or transmittance function. A twelve-channel multispectral light source was developed with improved spatial uniformity of spectral irradiance compared to a previous one. Experimental results of spectral matching imaging of human skin and vegetable leaves are demonstrated, as well as a preliminary feasibility test of imaging a reflective object using a test color chart.

  11. In-vivo full depth of eye imaging spectral domain optical coherence tomography

    NASA Astrophysics Data System (ADS)

    Dai, Cuixia; Zhou, Chuanqing; Jiao, Shuliang; Xi, Peng; Ren, Qiushi

    2011-09-01

    It is necessary to apply the spectral-domain optical coherence tomography (SD-OCT) to image the whole eye segment for practically iatrical application, but the imaging depth of SD-OCT is limited by the spectral resolution of the spectrometer. By now, no result about this research has been reported. In our study, a new dual channel dual focus OCT system is adopted to image the whole eye segment. The cornea and the crystalline lens are simultaneously imaged by using full range complex spectral-domain OCT in one channel, the retina is detected by the other. The new system was successfully tested in imaging of the volunteer' eye in vivo. The preliminary results presented in this paper demonstrated the feasibility of this approach.

  12. Multiphoton microscopy of cleared mouse organs

    NASA Astrophysics Data System (ADS)

    Parra, Sonia G.; Chia, Thomas H.; Zinter, Joseph P.; Levene, Michael J.

    2010-05-01

    Typical imaging depths with multiphoton microscopy (MPM) are limited to less than 300 μm in many tissues due to light scattering. Optical clearing significantly reduces light scattering by replacing water in the organ tissue with a fluid having a similar index of refraction to that of proteins. We demonstrate MPM of intact, fixed, cleared mouse organs with penetration depths and fields of view in excess of 2 mm. MPM enables the creation of large 3-D data sets with flexibility in pixel format and ready access to intrinsic fluorescence and second-harmonic generation. We present high-resolution images and 3-D image stacks of the brain, small intestine, large intestine, kidney, lung, and testicle with image sizes as large as 4096×4096 pixels.

  13. Point spread function engineering with multiphoton SPIFI

    NASA Astrophysics Data System (ADS)

    Wernsing, Keith A.; Field, Jeffrey J.; Domingue, Scott R.; Allende-Motz, Alyssa M.; DeLuca, Keith F.; Levi, Dean H.; DeLuca, Jennifer G.; Young, Michael D.; Squier, Jeff A.; Bartels, Randy A.

    2016-03-01

    MultiPhoton SPatIal Frequency modulated Imaging (MP-SPIFI) has recently demonstrated the ability to simultaneously obtain super-resolved images in both coherent and incoherent scattering processes -- namely, second harmonic generation and two-photon fluorescence, respectively.1 In our previous analysis, we considered image formation produced by the zero and first diffracted orders from the SPIFI modulator. However, the modulator is a binary amplitude mask, and therefore produces multiple diffracted orders. In this work, we extend our analysis to image formation in the presence of higher diffracted orders. We find that tuning the mask duty cycle offers a measure of control over the shape of super-resolved point spread functions in an MP-SPIFI microscope.

  14. Use of Sonicated Albumin (Infoson) to Enhance Arterial Spectral and Color Doppler Imaging

    SciTech Connect

    Abildgaard, Andreas; Egge, Tor S.; Klow, Nils-Einar; Jakobsen, Jarl A.

    1996-04-15

    Purpose: To examine the effect of an ultrasound contrast medium (UCM), Infoson, on Doppler examination of stenotic arteries. Methods: Stenoses were created in the common carotid artery of six piglets, and examined with spectral Doppler and color Doppler imaging during UCM infusion in the left ventricle. Results: UCM caused a mean increase in recorded maximal systolic and end-diastolic velocities of 5% and 6%, respectively, whil