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Sample records for imaging arrays hybridized

  1. Novel fabrication technique of hybrid structure lens array for 3D images

    NASA Astrophysics Data System (ADS)

    Lee, Junsik; Kim, Junoh; Kim, Cheoljoong; Shin, Dooseub; Koo, Gyohyun; Won, Yong Hyub

    2016-03-01

    Tunable liquid lens arrays can produce three dimensional images by using electrowetting principle that alters surface tensions by applying voltage. This method has advantages of fast response time and low power consumption. However, it is challenging to fabricate a high fill factor liquid lens array and operate three dimensional images which demand high diopter. This study describes a hybrid structure lens array which has not only a liquid lens array but a solid lens array. A concave-shape lens array is unavoidable when using only the liquid lens array and some voltages are needed to make the lens flat. By placing the solid lens array on the liquid lens array, initial diopter can be positive. To fabricate the hybrid structure lens array, a conventional lithographic process in semiconductor manufacturing is needed. A negative photoresist SU-8 was used as chamber master molds. PDMS and UV adhesive replica molding are done sequentially. Two immiscible liquids, DI water and dodecane, are injected in the fabricated chamber, followed by sealing. The fabricated structure has a 20 by 20 pattern of cylindrical shaped circle array and the aperture size of each lens is 1mm. The thickness of the overall hybrid structure is about 2.8mm. Hybrid structure lens array has many advantages. Solid lens array has almost 100% fill factor and allow high efficiency. Diopter can be increased by more than 200 and negative diopter can be shifted to the positive region. This experiment showed several properties of the hybrid structure and demonstrated its superiority.

  2. Simultaneous capturing of RGB and additional band images using hybrid color filter array

    NASA Astrophysics Data System (ADS)

    Kiku, Daisuke; Monno, Yusuke; Tanaka, Masayuki; Okutomi, Masatoshi

    2014-03-01

    Extra band information in addition to the RGB, such as the near-infrared (NIR) and the ultra-violet, is valuable for many applications. In this paper, we propose a novel color filter array (CFA), which we call "hybrid CFA," and a demosaicking algorithm for the simultaneous capturing of the RGB and the additional band images. Our proposed hybrid CFA and demosaicking algorithm do not rely on any specific correlation between the RGB and the additional band. Therefore, the additional band can be arbitrarily decided by users. Experimental results demonstrate that our proposed demosaicking algorithm with the proposed hybrid CFA can provide the additional band image while keeping the RGB image almost the same quality as the image acquired by using the standard Bayer CFA.

  3. Array tomography: imaging stained arrays.

    PubMed

    Micheva, Kristina D; O'Rourke, Nancy; Busse, Brad; Smith, Stephen J

    2010-11-01

    Array tomography is a volumetric microscopy method based on physical serial sectioning. Ultrathin sections of a plastic-embedded tissue are cut using an ultramicrotome, bonded in an ordered array to a glass coverslip, stained as desired, and imaged. The resulting two-dimensional image tiles can then be reconstructed computationally into three-dimensional volume images for visualization and quantitative analysis. The minimal thickness of individual sections permits high-quality rapid staining and imaging, whereas the array format allows reliable and convenient section handling, staining, and automated imaging. Also, the physical stability of the arrays permits images to be acquired and registered from repeated cycles of staining, imaging, and stain elution, as well as from imaging using multiple modalities (e.g., fluorescence and electron microscopy). Array tomography makes it possible to visualize and quantify previously inaccessible features of tissue structure and molecular architecture. However, careful preparation of the tissue is essential for successful array tomography; these steps can be time-consuming and require some practice to perfect. In this protocol, tissue arrays are imaged using conventional wide-field fluorescence microscopy. Images can be captured manually or, with the appropriate software and hardware, the process can be automated.

  4. Monolithic and hybrid near infrared detection and imaging based on poly-Ge photodiode arrays

    NASA Astrophysics Data System (ADS)

    Masini, G.; Colace, L.; Petulla, F.; Assanto, G.; Cencelli, V.; DeNotaristefani, F.

    2005-02-01

    In recent years, several Ge-on-Si technologies for the fabrication of near infrared photodetectors on Si substrates were proposed. In particular, using a low temperature (300 °C) technique, we have demonstrated poly-Ge_on_Si detectors with high speed and good NIR responsivity. The low process temperature allows the monolithic integration of the detectors as a final step in the fabrication of Si CMOS integrated circuits. After an introduction on poly-Ge, we describe a novel integrated chip (NIRCAM-1) designed as a readout/control circuit for arrays of 64 (32) poly-Ge_on_Si photodetectors. The photodiodes, monolithically integrated (wire-bonded with a hybrid approach) on the IC, generate a photocurrent which is then ADC converted after subtraction of the dark component, thus allowing a convenient digital readout of the array. The extensive optoelectronic characterization of the IC is presented.

  5. Underwater imaging using a hybrid Kirchhoff migration: direction of arrival method and a sparse surface sensor array.

    PubMed

    Dord, Jean-Francois; Farhat, Charbel

    2010-08-01

    This paper considers the problem of imaging a complex object submerged in shallow waters using a sparse surface sensor array and a hybrid signal processing method. This method is constructed by refining the Kirchhoff migration technique to incorporate a zoning of the sensors and an analysis of multiple reflections, and combining it with the direction of arrival estimation method. Its performance is assessed and analyzed with the shape identification of a mockup submarine by numerical simulation. The obtained numerical results highlight the potential of this approach for identifying underwater intruders.

  6. Hybrid Arrays for Chemical Sensing

    NASA Astrophysics Data System (ADS)

    Kramer, Kirsten E.; Rose-Pehrsson, Susan L.; Johnson, Kevin J.; Minor, Christian P.

    In recent years, multisensory approaches to environment monitoring for chemical detection as well as other forms of situational awareness have become increasingly popular. A hybrid sensor is a multimodal system that incorporates several sensing elements and thus produces data that are multivariate in nature and may be significantly increased in complexity compared to data provided by single-sensor systems. Though a hybrid sensor is itself an array, hybrid sensors are often organized into more complex sensing systems through an assortment of network topologies. Part of the reason for the shift to hybrid sensors is due to advancements in sensor technology and computational power available for processing larger amounts of data. There is also ample evidence to support the claim that a multivariate analytical approach is generally superior to univariate measurements because it provides additional redundant and complementary information (Hall, D. L.; Linas, J., Eds., Handbook of Multisensor Data Fusion, CRC, Boca Raton, FL, 2001). However, the benefits of a multisensory approach are not automatically achieved. Interpretation of data from hybrid arrays of sensors requires the analyst to develop an application-specific methodology to optimally fuse the disparate sources of data generated by the hybrid array into useful information characterizing the sample or environment being observed. Consequently, multivariate data analysis techniques such as those employed in the field of chemometrics have become more important in analyzing sensor array data. Depending on the nature of the acquired data, a number of chemometric algorithms may prove useful in the analysis and interpretation of data from hybrid sensor arrays. It is important to note, however, that the challenges posed by the analysis of hybrid sensor array data are not unique to the field of chemical sensing. Applications in electrical and process engineering, remote sensing, medicine, and of course, artificial

  7. Fabricating a hybrid imaging device

    NASA Technical Reports Server (NTRS)

    Wadsworth, Mark (Inventor); Atlas, Gene (Inventor)

    2003-01-01

    A hybrid detector or imager includes two substrates fabricated under incompatible processes. An array of detectors, such as charged-coupled devices, are formed on the first substrate using a CCD fabrication process, such as a buried channel or peristaltic process. One or more charge-converting amplifiers are formed on a second substrate using a CMOS fabrication process. The two substrates are then bonded together to form a hybrid detector.

  8. Computational Methods for the Analysis of Array Comparative Genomic Hybridization

    PubMed Central

    Chari, Raj; Lockwood, William W.; Lam, Wan L.

    2006-01-01

    Array comparative genomic hybridization (array CGH) is a technique for assaying the copy number status of cancer genomes. The widespread use of this technology has lead to a rapid accumulation of high throughput data, which in turn has prompted the development of computational strategies for the analysis of array CGH data. Here we explain the principles behind array image processing, data visualization and genomic profile analysis, review currently available software packages, and raise considerations for future software development. PMID:17992253

  9. Imaging antenna arrays

    NASA Technical Reports Server (NTRS)

    Rutledge, D. B.; Muha, M. S.

    1982-01-01

    Many millimeter and far-infrared imaging systems are limited in sensitivity and speed because they depend on a single scanned element. Because of recent advances in planar detectors such as Schottky diodes, superconducting tunnel junctions, and microbolometers, an attractive approach to this problem is a planar antenna array with integrated detectors. A planar line antenna array and optical system for imaging has been developed. The significant advances are a 'reverse-microscope' optical configuration and a modified bow-tie antenna design. In the 'reverse-microscope' configuration, a lens is attached to the bottom of the substrate containing the antennas. Imaging is done through the substrate. This configuration eliminates the troublesome effects of substrate surface waves. The substrate lens has only a single refracting surface, making possible a virtually aplanatic system, with little spherical aberration or coma. The array is characterized by an optical transfer function that is easily measured. An array with 19 dB crosstalk levels between adjacent antennas has been tested and it was found that the array captured 50 percent of the available power. This imaging system was diffraction limited.

  10. Space and power efficient hybrid counters array

    DOEpatents

    Gara, Alan G.; Salapura, Valentina

    2010-03-30

    A hybrid counter array device for counting events. The hybrid counter array includes a first counter portion comprising N counter devices, each counter device for receiving signals representing occurrences of events from an event source and providing a first count value corresponding to a lower order bits of the hybrid counter array. The hybrid counter array includes a second counter portion comprising a memory array device having N addressable memory locations in correspondence with the N counter devices, each addressable memory location for storing a second count value representing higher order bits of the hybrid counter array. A control device monitors each of the N counter devices of the first counter portion and initiates updating a value of a corresponding second count value stored at the corresponding addressable memory location in the second counter portion. Thus, a combination of the first and second count values provide an instantaneous measure of number of events received.

  11. Space and power efficient hybrid counters array

    DOEpatents

    Gara, Alan G.; Salapura, Valentina

    2009-05-12

    A hybrid counter array device for counting events. The hybrid counter array includes a first counter portion comprising N counter devices, each counter device for receiving signals representing occurrences of events from an event source and providing a first count value corresponding to a lower order bits of the hybrid counter array. The hybrid counter array includes a second counter portion comprising a memory array device having N addressable memory locations in correspondence with the N counter devices, each addressable memory location for storing a second count value representing higher order bits of the hybrid counter array. A control device monitors each of the N counter devices of the first counter portion and initiates updating a value of a corresponding second count value stored at the corresponding addressable memory location in the second counter portion. Thus, a combination of the first and second count values provide an instantaneous measure of number of events received.

  12. Nonlinear phased array imaging

    NASA Astrophysics Data System (ADS)

    Croxford, Anthony J.; Cheng, Jingwei; Potter, Jack N.

    2016-04-01

    A technique is presented for imaging acoustic nonlinearity within a specimen using ultrasonic phased arrays. Acoustic nonlinearity is measured by evaluating the difference in energy of the transmission bandwidth within the diffuse field produced through different focusing modes. The two different modes being classical beam forming, where delays are applied to different element of a phased array to physically focus the energy at a single location (parallel firing) and focusing in post processing, whereby one element at a time is fired and a focused image produced in post processing (sequential firing). Although these two approaches are linearly equivalent the difference in physical displacement within the specimen leads to differences in nonlinear effects. These differences are localized to the areas where the amplitude is different, essentially confining the differences to the focal point. Direct measurement at the focal point are however difficult to make. In order to measure this the diffuse field is used. It is a statistical property of the diffuse field that it represents the total energy in the system. If the energy in the diffuse field for both the sequential and parallel firing case is measured then the difference between these, within the input signal bandwidth, is largely due to differences at the focal spot. This difference therefore gives a localized measurement of where energy is moving out of the transmission bandwidth due to nonlinear effects. This technique is used to image fatigue cracks and other damage types undetectable with conventional linear ultrasonic measurements.

  13. Hybrid photomultiplier tube and photodiode parallel detection array for wideband optical spectroscopy of the breast guided by magnetic resonance imaging

    NASA Astrophysics Data System (ADS)

    El-Ghussein, Fadi; Mastanduno, Michael A.; Jiang, Shudong; Pogue, Brian W.; Paulsen, Keith D.

    2014-01-01

    A new optical parallel detection system of hybrid frequency and continuous-wave domains was developed to improve the data quality and accuracy in recovery of all breast optical properties. This new system was deployed in a previously existing system for magnetic resonance imaging (MRI)-guided spectroscopy, and allows incorporation of additional near-infrared wavelengths beyond 850 nm, with interlaced channels of photomultiplier tubes (PMTs) and silicon photodiodes (PDs). The acquisition time for obtaining frequency-domain data at six wavelengths (660, 735, 785, 808, 826, and 849 nm) and continuous-wave data at three wavelengths (903, 912, and 948 nm) is 12 min. The dynamic ranges of the detected signal are 105 and 106 for PMT and PD detectors, respectively. Compared to the previous detection system, the SNR ratio of frequency-domain detection was improved by nearly 103 through the addition of an RF amplifier and the utilization of programmable gain. The current system is being utilized in a clinical trial imaging suspected breast cancer tumors as detected by contrast MRI scans.

  14. Hybrid photomultiplier tube and photodiode parallel detection array for wideband optical spectroscopy of the breast guided by magnetic resonance imaging

    PubMed Central

    Mastanduno, Michael A.; Jiang, Shudong; Pogue, Brian W.; Paulsen, Keith D.

    2013-01-01

    Abstract. A new optical parallel detection system of hybrid frequency and continuous-wave domains was developed to improve the data quality and accuracy in recovery of all breast optical properties. This new system was deployed in a previously existing system for magnetic resonance imaging (MRI)-guided spectroscopy, and allows incorporation of additional near-infrared wavelengths beyond 850 nm, with interlaced channels of photomultiplier tubes (PMTs) and silicon photodiodes (PDs). The acquisition time for obtaining frequency-domain data at six wavelengths (660, 735, 785, 808, 826, and 849 nm) and continuous-wave data at three wavelengths (903, 912, and 948 nm) is 12 min. The dynamic ranges of the detected signal are 105 and 106 for PMT and PD detectors, respectively. Compared to the previous detection system, the SNR ratio of frequency-domain detection was improved by nearly 103 through the addition of an RF amplifier and the utilization of programmable gain. The current system is being utilized in a clinical trial imaging suspected breast cancer tumors as detected by contrast MRI scans. PMID:23979460

  15. Array tomography: semiautomated image alignment.

    PubMed

    Micheva, Kristina D; O'Rourke, Nancy; Busse, Brad; Smith, Stephen J

    2010-11-01

    Array tomography is a volumetric microscopy method based on physical serial sectioning. Ultrathin sections of a plastic-embedded tissue are cut using an ultramicrotome, bonded in an ordered array to a glass coverslip, stained as desired, and imaged. The resulting two-dimensional image tiles can then be reconstructed computationally into three-dimensional volume images for visualization and quantitative analysis. The minimal thickness of individual sections permits high-quality rapid staining and imaging, whereas the array format allows reliable and convenient section handling, staining, and automated imaging. Also, the physical stability of the arrays permits images to be acquired and registered from repeated cycles of staining, imaging, and stain elution, as well as from imaging using multiple modalities (e.g., fluorescence and electron microscopy). Array tomography makes it possible to visualize and quantify previously inaccessible features of tissue structure and molecular architecture. However, careful preparation of the tissue is essential for successful array tomography; these steps can be time-consuming and require some practice to perfect. Successful array tomography requires that the captured images be properly stacked and aligned, and the software to achieve these ends is freely available. This protocol describes the construction of volumetric image stacks from images of fluorescently labeled arrays for three-dimensional image visualization, analysis, and archiving.

  16. Hybrid Imaging in Oncology.

    PubMed

    Fatima, Nosheen; Zaman, Maseeh uz; Gnanasegaran, Gopinath; Zaman, Unaiza; Shahid, Wajeeha; Zaman, Areeba; Tahseen, Rabia

    2015-01-01

    In oncology various imaging modalities play a crucial role in diagnosis, staging, restaging, treatment monitoring and follow up of various cancers. Stand-alone morphological imaging like computerized tomography (CT) and magnetic resonance imaging (MRI) provide a high magnitude of anatomical details about the tumor but are relatively dumb about tumor physiology. Stand-alone functional imaging like positron emission tomography (PET) and single photon emission tomography (SPECT) are rich in functional information but provide little insight into tumor morphology. Introduction of first hybrid modality PET/CT is the one of the most successful stories of current century which has revolutionized patient care in oncology due to its high diagnostic accuracy. Spurred on by this success, more hybrid imaging modalities like SPECT/CT and PET/MR were introduced. It is the time to explore the potential applications of the existing hybrid modalities, developing and implementing standardized imaging protocols and train users in nuclear medicine and radiology. In this review we discuss three existing hybrid modalities with emphasis on their technical aspects and clinical applications in oncology.

  17. Solid state image sensing arrays

    NASA Technical Reports Server (NTRS)

    Sadasiv, G.

    1972-01-01

    The fabrication of a photodiode transistor image sensor array in silicon, and tests on individual elements of the array are described along with design for a scanning system for an image sensor array. The spectral response of p-n junctions was used as a technique for studying the optical-absorption edge in silicon. Heterojunction structures of Sb2S3- Si were fabricated and a system for measuring C-V curves on MOS structures was built.

  18. Initial Lab and Sky Test Results for the Teledyne Imaging System’s H4RG-10 CMOS-Hybrid 4k Visible Array for Use in Ground- and Space-based Astronomical and SSA Applications

    DTIC Science & Technology

    2007-01-01

    Initial Lab and Sky Test Results for the Teledyne Imaging System’s H4RG -10 CMOS-Hybrid 4k Visible Array for Use in Ground- and Space-based...00-00-2007 to 00-00-2007 4. TITLE AND SUBTITLE Initial Lab And Sky Test Results For The Teledyne Imaging System’s H4RG -10 CMOS-Hybrid 4k Visible...relative strengths and weaknesses. 5. DESCRIPTION OF THE H4RG -10 FPA AND GROUND TEST CAMERA During the J-MAPS concept study and subsequent risk

  19. Array imaging system for lithography

    NASA Astrophysics Data System (ADS)

    Kirner, Raoul; Mueller, Kevin; Malaurie, Pauline; Vogler, Uwe; Noell, Wilfried; Scharf, Toralf; Voelkel, Reinhard

    2016-09-01

    We present an integrated array imaging system based on a stack of microlens arrays. The microlens arrays are manufactured by melting resist and reactive ion etching (RIE) technology on 8'' wafers (fused silica) and mounted by wafer-level packaging (WLP)1. The array imaging system is configured for 1X projection (magnification m = +1) of a mask pattern onto a planar wafer. The optical system is based on two symmetric telescopes, thus anti-symmetric wavefront aberrations like coma, distortion, lateral color are minimal. Spherical aberrations are reduced by using microlenses with aspherical lens profiles. In our system design approach, sub-images of individual imaging channels do not overlap to avoid interference. Image superposition is achieved by moving the array imaging system during the exposure time. A tandem Koehler integrator illumination system (MO Exposure Optics) is used for illumination. The angular spectrum of the illumination light underfills the pupils of the imaging channels to avoid crosstalk. We present and discuss results from simulation, mounting and testing of a first prototype of the investigated array imaging system for lithography.

  20. Speckle imaging from an array

    NASA Astrophysics Data System (ADS)

    Riker, Jim F.; Tyler, Glenn A.; Vaughn, Jeff L.

    2016-09-01

    In this paper, we present two analytic theories developed recently to predict the performance of an imaging system composed of a phased array illuminator and a set of receiver subapertures. The receiver need not coincide with the transmitter. The two theories have been documented separately (ref. 1, 2), and the reader can find more details there - the theories present the analytic phased array irradiance on target in the presence of piston errors, and the resulting speckle pattern-induced imaging noise. The principal results presented here are the Signal to Noise Ratios (SNR) for both the radiometric portion of the problem and the speckle imaging portion of the problem.

  1. Nonlinear Ultrasonic Phased Array Imaging

    NASA Astrophysics Data System (ADS)

    Potter, J. N.; Croxford, A. J.; Wilcox, P. D.

    2014-10-01

    This Letter reports a technique for the imaging of acoustic nonlinearity. By contrasting the energy of the diffuse field produced through the focusing of an ultrasonic array by delayed parallel element transmission with that produced by postprocessing of sequential transmission data, acoustic nonlinearity local to the focal point is measured. Spatially isolated wave distortion is inferred without requiring interrogation of the wave at the inspection point, thereby allowing nonlinear imaging through depth.

  2. Array Imaging of Noisy Materials

    NASA Astrophysics Data System (ADS)

    Wilcox, P. D.

    2011-06-01

    The ultimate limit on ultrasonic defect detectability is the coherent noise due to material backscatter. A model of such noise in ultrasonic array images is developed based on the single scattering assumption. The implications of the model are discussed and supported with some experimental examples. In the case of a copper specimen, it is shown that an improvement in signal to coherent noise ratio of over 30 dB can be obtained by optimization of imaging parameters.

  3. Nonlinear ultrasonic phased array imaging.

    PubMed

    Potter, J N; Croxford, A J; Wilcox, P D

    2014-10-03

    This Letter reports a technique for the imaging of acoustic nonlinearity. By contrasting the energy of the diffuse field produced through the focusing of an ultrasonic array by delayed parallel element transmission with that produced by postprocessing of sequential transmission data, acoustic nonlinearity local to the focal point is measured. Spatially isolated wave distortion is inferred without requiring interrogation of the wave at the inspection point, thereby allowing nonlinear imaging through depth.

  4. Gigapixel imaging with microlens arrays

    NASA Astrophysics Data System (ADS)

    Orth, Antony; Schonbrun, Ethan

    2016-03-01

    A crucial part of the drug discovery process involves imaging the response of thousands of cell cultures to candidate drugs. Quantitative parameters from these "high content screens", such as protein expression and cell morphology, are extracted from fluorescence and brightfield micrographs. Due to the sheer number of cells that need to imaged for adequate statistics, the imaging time itself is a major bottleneck. Automated microscopes image small fields-of-view (FOVs) serially, which are then stitched together to form gigapixel-scale mosaics. We have developed a microscopy architecture that reduces mechanical overhead of traditional large field-of-view by parallelizing the image capture process. Instead of a single objective lens imaging FOVs one by one, we employ a microlens array for continuous photon capture, resulting in a 3-fold throughput increase. In this contribution, we present the design and imaging results of this microscopy architecture in three different contrast modes: multichannel fluorescence, hyperspectral fluorescence and brightfield.

  5. Quantitative ultrasonic phased array imaging

    NASA Astrophysics Data System (ADS)

    Engle, Brady J.; Schmerr, Lester W., Jr.; Sedov, Alexander

    2014-02-01

    When imaging with ultrasonic phased arrays, what do we actually image? What quantitative information is contained in the image? Ad-hoc delay-and-sum methods such as the synthetic aperture focusing technique (SAFT) and the total focusing method (TFM) fail to answer these questions. We have shown that a new quantitative approach allows the formation of flaw images by explicitly inverting the Thompson-Gray measurement model. To examine the above questions, we have set up a software simulation test bed that considers a 2-D scalar scattering problem of a cylindrical inclusion with the method of separation of variables. It is shown that in SAFT types of imaging the only part of the flaw properly imaged is the front surface specular response of the flaw. Other responses (back surface reflections, creeping waves, etc.) are improperly imaged and form artifacts in the image. In the case of TFM-like imaging the quantity being properly imaged is an angular integration of the front surface reflectivity. The other, improperly imaged responses are also averaged, leading to a reduction in some of the artifacts present. Our results have strong implications for flaw sizing and flaw characterization with delay-and-sum images.

  6. Array Technology for Terahertz Imaging

    NASA Technical Reports Server (NTRS)

    Reck, Theodore; Siles, Jose; Jung, Cecile; Gill, John; Lee, Choonsup; Chattopadhyay, Goutam; Mehdi, Imran; Cooper, Ken

    2012-01-01

    Heterodyne terahertz (0.3 - 3THz) imaging systems are currently limited to single or a low number of pixels. Drastic improvements in imaging sensitivity and speed can be achieved by replacing single pixel systems with an array of detectors. This paper presents an array topology that is being developed at the Jet Propulsion Laboratory based on the micromachining of silicon. This technique fabricates the array's package and waveguide components by plasma etching of silicon, resulting in devices with precision surpassing that of current metal machining techniques. Using silicon increases the versatility of the packaging, enabling a variety of orientations of circuitry within the device which increases circuit density and design options. The design of a two-pixel transceiver utilizing a stacked architecture is presented that achieves a pixel spacing of 10mm. By only allowing coupling from the top and bottom of the package the design can readily be arrayed in two dimensions with a spacing of 10mm x 18mm.

  7. Handheld ultrasound array imaging device

    NASA Astrophysics Data System (ADS)

    Hwang, Juin-Jet; Quistgaard, Jens

    1999-06-01

    A handheld ultrasound imaging device, one that weighs less than five pounds, has been developed for diagnosing trauma in the combat battlefield as well as a variety of commercial mobile diagnostic applications. This handheld device consists of four component ASICs, each is designed using the state of the art microelectronics technologies. These ASICs are integrated with a convex array transducer to allow high quality imaging of soft tissues and blood flow in real time. The device is designed to be battery driven or ac powered with built-in image storage and cineloop playback capability. Design methodologies of a handheld device are fundamentally different to those of a cart-based system. As system architecture, signal and image processing algorithm as well as image control circuit and software in this device is deigned suitably for large-scale integration, the image performance of this device is designed to be adequate to the intent applications. To elongate the battery life, low power design rules and power management circuits are incorporated in the design of each component ASIC. The performance of the prototype device is currently being evaluated for various applications such as a primary image screening tool, fetal imaging in Obstetrics, foreign object detection and wound assessment for emergency care, etc.

  8. Imaging phased telescope array study

    NASA Technical Reports Server (NTRS)

    Harvey, James E.

    1989-01-01

    The problems encountered in obtaining a wide field-of-view with large, space-based direct imaging phased telescope arrays were considered. After defining some of the critical systems issues, previous relevant work in the literature was reviewed and summarized. An extensive list was made of potential error sources and the error sources were categorized in the form of an error budget tree including optical design errors, optical fabrication errors, assembly and alignment errors, and environmental errors. After choosing a top level image quality requirment as a goal, a preliminary tops-down error budget allocation was performed; then, based upon engineering experience, detailed analysis, or data from the literature, a bottoms-up error budget reallocation was performed in an attempt to achieve an equitable distribution of difficulty in satisfying the various allocations. This exercise provided a realistic allocation for residual off-axis optical design errors in the presence of state-of-the-art optical fabrication and alignment errors. Three different computational techniques were developed for computing the image degradation of phased telescope arrays due to aberrations of the individual telescopes. Parametric studies and sensitivity analyses were then performed for a variety of subaperture configurations and telescope design parameters in an attempt to determine how the off-axis performance of a phased telescope array varies as the telescopes are scaled up in size. The Air Force Weapons Laboratory (AFWL) multipurpose telescope testbed (MMTT) configuration was analyzed in detail with regard to image degradation due to field curvature and distortion of the individual telescopes as they are scaled up in size.

  9. Hybrid ultrasound imaging techniques (fusion imaging).

    PubMed

    Sandulescu, Daniela Larisa; Dumitrescu, Daniela; Rogoveanu, Ion; Saftoiu, Adrian

    2011-01-07

    Visualization of tumor angiogenesis can facilitate non-invasive evaluation of tumor vascular characteristics to supplement the conventional diagnostic imaging goals of depicting tumor location, size, and morphology. Hybrid imaging techniques combine anatomic [ultrasound, computed tomography (CT), and/or magnetic resonance imaging (MRI)] and molecular (single photon emission CT and positron emission tomography) imaging modalities. One example is real-time virtual sonography, which combines ultrasound (grayscale, colour Doppler, or dynamic contrast harmonic imaging) with contrast-enhanced CT/MRI. The benefits of fusion imaging include an increased diagnostic confidence, direct comparison of the lesions using different imaging modalities, more precise monitoring of interventional procedures, and reduced radiation exposure.

  10. Breadboard linear array scan imager program

    NASA Technical Reports Server (NTRS)

    1975-01-01

    The performance was evaluated of large scale integration photodiode arrays in a linear array scan imaging system breadboard for application to multispectral remote sensing of the earth's resources. Objectives, approach, implementation, and test results of the program are presented.

  11. Microfabrication of encoded microparticle array for multiplexed DNA hybridization detection.

    PubMed

    Zhi, Zheng-Liang; Morita, Yasutaka; Yamamura, Shouhei; Tamiya, Eiichi

    2005-05-21

    A strategy for the high-sensitivity, high-selectivity, and multiplexed detection of oligonucleotide hybridizations has been developed with an encoded Ni microparticle random array that was manufactured by a "top-down" approach using micromachining and microfabrication techniques.

  12. Broadband-antireflective hybrid nanopillar array for photovoltaic application

    SciTech Connect

    Watanabe, Keiji Yamamoto, Jiro; Tsuchiya, Ryuta

    2015-08-28

    Subwavelength structures such as nanopillars, nanoholes, and nanodomes have recently attracted considerable attention as antireflective structures for solar cells. Recent studies on the optical property of nanopillar array revealed that the reflection minimum is related to the diameter, the pitch, and the height of nanopillars. Here, we investigate the “hybrid” nanopillar array, which is composed of different diameters of nanopillars. Finite differential time domain simulations revealed that the photogeneration in a hybrid nanopillar array is spatially heterogeneous: carriers are generated mainly in the narrower pillars for short-wavelength incident light and in the thicker pillars for long-wavelength light, respectively. Hybrid silicon nanopillar arrays fabricated by using electron beam lithography and dry etching show excellent broadband antireflection property. Hybrid nanopillar array is thus highly promising for next-generation antireflection for photovoltaic applications.

  13. Characterization of microrod arrays by image analysis

    NASA Astrophysics Data System (ADS)

    Hillebrand, Reinald; Grimm, Silko; Giesa, Reiner; Schmidt, Hans-Werner; Mathwig, Klaus; Gösele, Ulrich; Steinhart, Martin

    2009-04-01

    The uniformity of the properties of array elements was evaluated by statistical analysis of microscopic images of array structures, assuming that the brightness of the array elements correlates quantitatively or qualitatively with a microscopically probed quantity. Derivatives and autocorrelation functions of cumulative frequency distributions of the object brightnesses were used to quantify variations in object properties throughout arrays. Thus, different specimens, the same specimen at different stages of its fabrication or use, and different imaging conditions can be compared systematically. As an example, we analyzed scanning electron micrographs of microrod arrays and calculated the percentage of broken microrods.

  14. Hybrid Enrichment Verification Array: Module Characterization Studies

    SciTech Connect

    Zalavadia, Mital A.; Smith, Leon E.; McDonald, Benjamin S.; Kulisek, Jonathan A.; Mace, Emily K.; Deshmukh, Nikhil S.

    2016-03-01

    The work presented in this report is focused on the characterization and refinement of the Hybrid Enrichment Verification Array (HEVA) approach, which combines the traditional 186-keV 235U signature with high-energy prompt gamma rays from neutron capture in the detector and surrounding collimator material, to determine the relative enrichment and 235U mass of the cylinder. The design of the HEVA modules (hardware and software) deployed in the current field trial builds on over seven years of study and evolution by PNNL, and consists of a ø3''×3'' NaI(Tl) scintillator coupled to an Osprey digital multi-channel analyzer tube base from Canberra. The core of the HEVA methodology, the high-energy prompt gamma-ray signature, serves as an indirect method for the measurement of total neutron emission from the cylinder. A method for measuring the intrinsic efficiency of this “non-traditional” neutron signature and the results from a benchmark experiment are presented. Also discussed are potential perturbing effects on the non-traditional signature, including short-lived activation of materials in the HEVA module. Modeling and empirical results are presented to demonstrate that such effects are expected to be negligible for the envisioned implementation scenario. In comparison to previous versions, the new design boosts the high-energy prompt gamma-ray signature, provides more flexible and effective collimation, and improves count-rate management via commercially available pulse-processing electronics with a special modification prompted by PNNL.

  15. Optimizing image fidelity with arrays

    NASA Astrophysics Data System (ADS)

    Corder, Stuartt Allan

    2009-11-01

    Through simulations, I have investigated the limitations imposed upon the image fidelity of interferometric observations by primary beam errors. Significant antenna surface and pointing errors lead to the greatest reduction in fidelity for most cases, but, when present, imaginary beam components dominate the degradation. Beam errors were addressed by optimizing the antenna surfaces and aligning the optics and then determining baseline based primary beams. Methods for applying these measured patterns to actual data were discussed. Pointing errors were reduced by improving the fit to the pointing model. Further reduction was achieved by integrating the use of optical pointing observations into standard radio observing. The greatest benefit was seen during daytime observations, but general reduction in pointing error was seen.The dense uv-coverage of the Combined Array for Research in Millimeter-wave Astronomy (CARMA) coupled with the techniques described above make it an ideal instrument for imaging extended regions with high fidelity. The NGC 7538 star-forming cloud contains dense peaks, many high-mass stars and associated accretion disks, and multiple outflows. I obtained CARMA images at the requisite fidelity, employing the above techniques. These mosaiced, spectral-line, and 3-mm band continuum observations provide a clearer picture of the bulk morphology of the region and the fine-scale structures within it than has hitherto been possible. For the first time in the region, infall signatures were found towards two sources, allowing comparison of the infall and outflow mass and verifying that significant accretion (>10-4M⊙ yr-1) continues well into the stage where a massive protostar has formed. One of the sources, NGC 7538IRS1, shows one of the few definitive signatures of an inverse PCygni profile towards a massive protostar. Three outflows were found centered on sources that are separated by 10,000-20,000 AU in projection. The calculated energy injection rate

  16. First-Generation Hybrid Compact Compton Imager

    SciTech Connect

    Cunningham, M; Burks, M; Chivers, D; Cork, C; Fabris, L; Gunter, D; Krings, T; Lange, D; Hull, E; Mihailescu, L; Nelson, K; Niedermayr, T; Protic, D; Valentine, J; Vetter, K; Wright, D

    2005-11-07

    At Lawrence Livermore National Laboratory, we are pursuing the development of a gamma-ray imaging system using the Compton effect. We have built our first generation hybrid Compton imaging system, and we have conducted initial calibration and image measurements using this system. In this paper, we present the details of the hybrid Compton imaging system and initial calibration and image measurements.

  17. A functional hybrid memristor crossbar-array/CMOS system for data storage and neuromorphic applications.

    PubMed

    Kim, Kuk-Hwan; Gaba, Siddharth; Wheeler, Dana; Cruz-Albrecht, Jose M; Hussain, Tahir; Srinivasa, Narayan; Lu, Wei

    2012-01-11

    Crossbar arrays based on two-terminal resistive switches have been proposed as a leading candidate for future memory and logic applications. Here we demonstrate a high-density, fully operational hybrid crossbar/CMOS system composed of a transistor- and diode-less memristor crossbar array vertically integrated on top of a CMOS chip by taking advantage of the intrinsic nonlinear characteristics of the memristor element. The hybrid crossbar/CMOS system can reliably store complex binary and multilevel 1600 pixel bitmap images using a new programming scheme.

  18. Initial Lab and Sky Test Results for the Teledyne Imaging System's H4RG-10 CMOS-Hybrid 4k Visible Array for Use in Ground- and Space-based Astronomical and SSA Applications

    NASA Astrophysics Data System (ADS)

    Dorland, B.; Hennessy, G.; Zacharias, N.; Gaume, R.; Shu, P.; Miko, L.; Rollins, C.; Waczynski, A.

    We report on the first set of laboratory and telescope tests of the Teledyne Imaging System's (TIS) H4RG-10 CMOS-Hybrid visible focal plane array (FPA). This family of detectors has been chosen as the baseline for USNO's proposed J-MAPS space astrometry mission to close a number of capability gaps. While this FPA has been designed for precision astrometry, it has potentially significant Space Situational Awareness (SSA) applications. Because of the hybrid design, which consists of separate readout and detector layers connected by Indium bump-bonds, this FPA has the readout flexibility of advanced CMOS readout integrated circuits (ROICs), including non-destructive readout, random access windowing and selective reset, and near-CCD performance in terms of fill factor, quantum efficiency, read noise and dark current. Our laboratory testing, performed at Goddard Space Flight Center's Detector Characterization Lab, includes measures of absolute spectral quantum efficiency, flat-field response uniformity, read noise, dark current as a function of operating temperature, inter-pixel crosstalk, and persistence. Sky testing, performed at Naval Observatory Flagstaff Station, consists of astrometric and photometric performance characterization. We discuss implications for the use of this detector in future ground- and space-based astrometric, astronomical and SSA applications.

  19. Arrays of probes for positional sequencing by hybridization

    DOEpatents

    Cantor, Charles R.; Prezetakiewiczr, Marek; Smith, Cassandra L.; Sano, Takeshi

    2008-01-15

    This invention is directed to methods and reagents useful for sequencing nucleic acid targets utilizing sequencing by hybridization technology comprising probes, arrays of probes and methods whereby sequence information is obtained rapidly and efficiently in discrete packages. That information can be used for the detection, identification, purification and complete or partial sequencing of a particular target nucleic acid. When coupled with a ligation step, these methods can be performed under a single set of hybridization conditions. The invention also relates to the replication of probe arrays and methods for making and replicating arrays of probes which are useful for the large scale manufacture of diagnostic aids used to screen biological samples for specific target sequences. Arrays created using PCR technology may comprise probes with 5'- and/or 3'-overhangs.

  20. Quasi-random array imaging collimator

    DOEpatents

    Fenimore, E.E.

    1980-08-20

    A hexagonally shaped quasi-random no-two-holes-touching imaging collimator. The quasi-random array imaging collimator eliminates contamination from small angle off-axis rays by using a no-two-holes-touching pattern which simultaneously provides for a self-supporting array increasing throughput by elimination of a substrate. The present invention also provides maximum throughput using hexagonally shaped holes in a hexagonal lattice pattern for diffraction limited applications. Mosaicking is also disclosed for reducing fabrication effort.

  1. Miniature hybrid optical imaging lens

    DOEpatents

    Sitter, Jr., David N.; Simpson, Marc L.

    1997-01-01

    A miniature lens system that corrects for imaging and chromatic aberrations, the lens system being fabricated from primarily commercially-available components. A first element at the input to a lens housing is an aperture stop. A second optical element is a refractive element with a diffractive element closely coupled to, or formed a part of, the rear surface of the refractive element. Spaced closely to the diffractive element is a baffle to limit the area of the image, and this is closely followed by a second refractive lens element to provide the final correction. The image, corrected for aberrations exits the last lens element to impinge upon a detector plane were is positioned any desired detector array. The diffractive element is fabricated according to an equation that includes, as variables, the design wavelength, the index of refraction and the radius from an optical axis of the lens system components.

  2. Miniature hybrid optical imaging lens

    DOEpatents

    Sitter, D.N. Jr.; Simpson, M.L.

    1997-10-21

    A miniature lens system that corrects for imaging and chromatic aberrations is disclosed, the lens system being fabricated from primarily commercially-available components. A first element at the input to a lens housing is an aperture stop. A second optical element is a refractive element with a diffractive element closely coupled to, or formed a part of, the rear surface of the refractive element. Spaced closely to the diffractive element is a baffle to limit the area of the image, and this is closely followed by a second refractive lens element to provide the final correction. The image, corrected for aberrations exits the last lens element to impinge upon a detector plane were is positioned any desired detector array. The diffractive element is fabricated according to an equation that includes, as variables, the design wavelength, the index of refraction and the radius from an optical axis of the lens system components. 2 figs.

  3. Passive cavitation imaging with ultrasound arrays.

    PubMed

    Salgaonkar, Vasant A; Datta, Saurabh; Holland, Christy K; Mast, T Douglas

    2009-12-01

    A method is presented for passive imaging of cavitational acoustic emissions using an ultrasound array, with potential application in real-time monitoring of ultrasound ablation. To create such images, microbubble emissions were passively sensed by an imaging array and dynamically focused at multiple depths. In this paper, an analytic expression for a passive image is obtained by solving the Rayleigh-Sommerfield integral, under the Fresnel approximation, and passive images were simulated. A 192-element array was used to create passive images, in real time, from 520-kHz ultrasound scattered by a 1-mm steel wire. Azimuthal positions of this target were accurately estimated from the passive images. Next, stable and inertial cavitation was passively imaged in saline solution sonicated at 520 kHz. Bubble clusters formed in the saline samples were consistently located on both passive images and B-scans. Passive images were also created using broadband emissions from bovine liver sonicated at 2.2 MHz. Agreement was found between the images and source beam shape, indicating an ability to map therapeutic ultrasound beams in situ. The relation between these broadband emissions, sonication amplitude, and exposure conditions are discussed.

  4. Staring arrays - The future lightweight imagers

    NASA Astrophysics Data System (ADS)

    Dennis, P. N. J.; Dann, R. J.

    1985-01-01

    High performance thermal imagers, such as the common modules, are now readily available. These systems generally employ a scanning mechanism to generate the two-dimensional display which makes their adaptation to cheap, lightweight, small imagers difficult. However, with the advent of two-dimensional close packed arrays of infrared detectors the development of such a system is now becoming feasible. A small imager using cadium mercury telluride detectors has been produced commercially. The system has been designed to be adaptable to use both 3-5-micrometer and 8-14-micrometer arrays, and to study various electronic correction mechanisms.

  5. Blocked impurity band hybrid infrared focal plane arrays for astronomy

    NASA Technical Reports Server (NTRS)

    Reynolds, D. B.; Seib, D. H.; Stetson, S. B.; Herter, T.; Rowlands, N.

    1989-01-01

    High-performance infrared hybrid focal plane arrays using 10- x 50-element Si:As blocked-impurity-band (BIB) detectors (cutoff wavelength = 28 microns) and matching switched MOSFET multiplexers have been developed and characterized for space astronomy. Use of impurity-band-conduction technology provides detectors which are nuclear-radiation-hard and free of the many anomalies associated with conventional silicon photoconductive detectors. Emphasis in the present work is on recent advances in detector material quality which have led to significantly improved detector and hybrid characteristics. Results demonstrating increased quantum efficiency (particularly at short-wavelength infrared), obtained by varying the BIB detector properties (infrared active layer thickness and arsenic doping profile), are summarized. Measured read noise and dark current for different temperatures are reported. The hybrid array performance achieved demonstrates that BIB detectors are well suited for use in astronomical instrumentation.

  6. Array imaging of localized objects in homogeneous and heterogeneous media

    NASA Astrophysics Data System (ADS)

    Chai, Anwei; Moscoso, Miguel; Papanicolaou, George

    2016-10-01

    We present a comprehensive study of the resolution and stability properties of sparse promoting optimization theories applied to narrow band array imaging of localized scatterers. We consider homogeneous and heterogeneous media, and multiple and single scattering situations. When the media is homogeneous with strong multiple scattering between scatterers, we give a non-iterative formulation to find the locations and reflectivities of the scatterers from a nonlinear inverse problem in two steps, using either single or multiple illuminations. We further introduce an approach that uses the top singular vectors of the response matrix as optimal illuminations, which improves the robustness of sparse promoting optimization with respect to additive noise. When multiple scattering is negligible, the optimization problem becomes linear and can be reduced to a hybrid-{{\\ell }}1 method when optimal illuminations are used. When the media is random, and the interaction with the unknown inhomogeneities can be primarily modeled by wavefront distortions, we address the statistical stability of these methods. We analyze the fluctuations of the images obtained with the hybrid-{{\\ell }}1 method, and we show that it is stable with respect to different realizations of the random medium provided the imaging array is large enough. We compare the performance of the hybrid-{{\\ell }}1 method in random media to the widely used Kirchhoff migration and the multiple signal classification methods.

  7. Optimization of ultrasonic array inspections using an efficient hybrid model and real crack shapes

    NASA Astrophysics Data System (ADS)

    Felice, Maria V.; Velichko, Alexander; Wilcox, Paul D.; Barden, Tim; Dunhill, Tony

    2015-03-01

    Models which simulate the interaction of ultrasound with cracks can be used to optimize ultrasonic array inspections, but this approach can be time-consuming. To overcome this issue an efficient hybrid model is implemented which includes a finite element method that requires only a single layer of elements around the crack shape. Scattering Matrices are used to capture the scattering behavior of the individual cracks and a discussion on the angular degrees of freedom of elastodynamic scatterers is included. Real crack shapes are obtained from X-ray Computed Tomography images of cracked parts and these shapes are inputted into the hybrid model. The effect of using real crack shapes instead of straight notch shapes is demonstrated. An array optimization methodology which incorporates the hybrid model, an approximate single-scattering relative noise model and the real crack shapes is then described.

  8. Optimization of ultrasonic array inspections using an efficient hybrid model and real crack shapes

    SciTech Connect

    Felice, Maria V.; Velichko, Alexander Wilcox, Paul D.; Barden, Tim; Dunhill, Tony

    2015-03-31

    Models which simulate the interaction of ultrasound with cracks can be used to optimize ultrasonic array inspections, but this approach can be time-consuming. To overcome this issue an efficient hybrid model is implemented which includes a finite element method that requires only a single layer of elements around the crack shape. Scattering Matrices are used to capture the scattering behavior of the individual cracks and a discussion on the angular degrees of freedom of elastodynamic scatterers is included. Real crack shapes are obtained from X-ray Computed Tomography images of cracked parts and these shapes are inputted into the hybrid model. The effect of using real crack shapes instead of straight notch shapes is demonstrated. An array optimization methodology which incorporates the hybrid model, an approximate single-scattering relative noise model and the real crack shapes is then described.

  9. Imaging Arrays With Improved Transmit Power Capability

    PubMed Central

    Zipparo, Michael J.; Bing, Kristin F.; Nightingale, Kathy R.

    2010-01-01

    Bonded multilayer ceramics and composites incorporating low-loss piezoceramics have been applied to arrays for ultrasound imaging to improve acoustic transmit power levels and to reduce internal heating. Commercially available hard PZT from multiple vendors has been characterized for microstructure, ability to be processed, and electroacoustic properties. Multilayers using the best materials demonstrate the tradeoffs compared with the softer PZT5-H typically used for imaging arrays. Three-layer PZT4 composites exhibit an effective dielectric constant that is three times that of single layer PZT5H, a 50% higher mechanical Q, a 30% lower acoustic impedance, and only a 10% lower coupling coefficient. Application of low-loss multilayers to linear phased and large curved arrays results in equivalent or better element performance. A 3-layer PZT4 composite array achieved the same transmit intensity at 40% lower transmit voltage and with a 35% lower face temperature increase than the PZT-5 control. Although B-mode images show similar quality, acoustic radiation force impulse (ARFI) images show increased displacement for a given drive voltage. An increased failure rate for the multilayers following extended operation indicates that further development of the bond process will be necessary. In conclusion, bonded multilayer ceramics and composites allow additional design freedom to optimize arrays and improve the overall performance for increased acoustic output while maintaining image quality. PMID:20875996

  10. Lensless image scanner using multilayered aperture array for noncontact imaging

    NASA Astrophysics Data System (ADS)

    Kawano, Hiroyuki

    2016-10-01

    We propose a new imaging system of a simple structure that uses a set of layered aperture arrays above a linear image sensor instead of an imaging lens. The image scanner transfers the image information by detecting the scattering rays from the object directly without any collecting power, as if it were an optical stamp. Since the aperture arrays shield the stray rays propagating obliquely, the image information can be read with high resolution even if the object floats within a few millimeters. The aperture arrays with staggered alignment in two lines widen the space with the adjacent pixel without decimating information. We manufactured a prototype model of 300-dpi resolution, whose height is as little as 5 mm. The experimental result shows that ghost images can be restricted sufficiently, and our scanner can clearly read an object within a space of <3.5 mm, meaning that it has a large depth of field of 3.5 mm.

  11. Self imaging in segmented waveguide arrays

    NASA Astrophysics Data System (ADS)

    Heinrich, Matthias; Szameit, Alexander; Dreisow, Felix; Pertsch, Thomas; Nolte, Stefan; Tünnermann, Andreas; Suran, Eric; Louradour, Frédéric; Bathélémy, Alain; Longhi, Stefano

    2009-02-01

    Self-imaging in integrated optical devices is interesting for many applications including image transmission, optical collimation and even reshaping of ultrashort laser pulses. However, in general this relies on boundary-free light propagation, since interaction with boundaries results in a considerable distortion of the self-imaging effect. This problem can be overcome in waveguide arrays by segmentation of particular lattice sites, yielding phase shifts which result in image reconstruction in one- as well as two-dimensional configurations. Here, we demonstrate the first experimental realization of this concept. For the fabrication of the segmented waveguide arrays we used the femtosecond laser direct-writing technique. The total length of the arrays is 50mm with a waveguide spacing of 16 μm and 20μm in the one- and two-dimensional case, respectively. The length of the segmented area was 2.6mm, while the segmentation period was chosen to be 16 μm. This results in a complete inversion of the global phase of the travelling field inside the array, so that the evolution dynamics are reversed and the input field is imaged onto the sample output facet. Accordingly, segmented integrated optical devices provide a new and attractive opportunity for image transmission in finite systems.

  12. Design, processing and testing of LSI arrays, hybrid microelectronics task

    NASA Technical Reports Server (NTRS)

    Himmel, R. P.; Stuhlbarg, S. M.; Ravetti, R. G.; Zulueta, P. J.; Rothrock, C. W.

    1979-01-01

    Mathematical cost models previously developed for hybrid microelectronic subsystems were refined and expanded. Rework terms related to substrate fabrication, nonrecurring developmental and manufacturing operations, and prototype production are included. Sample computer programs were written to demonstrate hybrid microelectric applications of these cost models. Computer programs were generated to calculate and analyze values for the total microelectronics costs. Large scale integrated (LST) chips utilizing tape chip carrier technology were studied. The feasibility of interconnecting arrays of LSU chips utilizing tape chip carrier and semiautomatic wire bonding technology was demonstrated.

  13. Methylation profiling using methylated DNA immunoprecipitation and tiling array hybridization.

    PubMed

    Cheung, Hoi-Hung; Lee, Tin-Lap; Rennert, Owen M; Chan, Wai-Yee

    2012-01-01

    DNA methylation is an important epigenetic modification that regulates development and plays a role in the pathophysiology of many diseases. It is dynamically changed during germline development. Methylated DNA immunoprecipitation (MeDIP) is an efficient, cost-effective method for locus-specific and genome-wide analysis. Methylated DNA fragments are enriched by a 5-methylcytidine-recognizing antibody, therefore allowing the analysis of both CpG and non-CpG methylation. The enriched DNA fragments can be amplified and hybridized to tiling arrays covering CpG islands, promoters, or the entire genome. Comparison of different methylomes permits the discovery of differentially methylated regions that might be important in disease- or tissue-specific expression. Here, we describe an established MeDIP protocol and tiling array hybridization method for profiling methylation of testicular germ cells.

  14. Coherent hybrid electromagnetic field imaging

    DOEpatents

    Cooke, Bradly J.; Guenther, David C.

    2008-08-26

    An apparatus and corresponding method for coherent hybrid electromagnetic field imaging of a target, where an energy source is used to generate a propagating electromagnetic beam, an electromagnetic beam splitting means to split the beam into two or more coherently matched beams of about equal amplitude, and where the spatial and temporal self-coherence between each two or more coherently matched beams is preserved. Two or more differential modulation means are employed to modulate each two or more coherently matched beams with a time-varying polarization, frequency, phase, and amplitude signal. An electromagnetic beam combining means is used to coherently combine said two or more coherently matched beams into a coherent electromagnetic beam. One or more electromagnetic beam controlling means are used for collimating, guiding, or focusing the coherent electromagnetic beam. One or more apertures are used for transmitting and receiving the coherent electromagnetic beam to and from the target. A receiver is used that is capable of square-law detection of the coherent electromagnetic beam. A waveform generator is used that is capable of generation and control of time-varying polarization, frequency, phase, or amplitude modulation waveforms and sequences. A means of synchronizing time varying waveform is used between the energy source and the receiver. Finally, a means of displaying the images created by the interaction of the coherent electromagnetic beam with target is employed.

  15. Biaxially stretchable supercapacitors based on the buckled hybrid fiber electrode array

    NASA Astrophysics Data System (ADS)

    Zhang, Nan; Zhou, Weiya; Zhang, Qiang; Luan, Pingshan; Cai, Le; Yang, Feng; Zhang, Xiao; Fan, Qingxia; Zhou, Wenbin; Xiao, Zhuojian; Gu, Xiaogang; Chen, Huiliang; Li, Kewei; Xiao, Shiqi; Wang, Yanchun; Liu, Huaping; Xie, Sishen

    2015-07-01

    In order to meet the growing need for smart bionic devices and epidermal electronic systems, biaxial stretchability is essential for energy storage units. Based on porous single-walled carbon nanotube/poly(3,4-ethylenedioxythiophene) (SWCNT/PEDOT) hybrid fiber, we designed and fabricated a biaxially stretchable supercapacitor, which possesses a unique configuration of the parallel buckled hybrid fiber array. Owing to the reticulate SWCNT film and the improved fabrication technique, the hybrid fiber retained its porous architecture both outwardly and inwardly, manifesting a superior capacity of 215 F g-1. H3PO4-polyvinyl alcohol gel with an optimized component ratio was introduced as both binder and stretchable electrolyte, which contributed to the regularity and stability of the buckled fiber array. The buckled structure and the quasi one-dimensional character of the fibers endow the supercapacitor with 100% stretchability along all directions. In addition, the supercapacitor exhibited good transparency, as well as excellent electrochemical properties and stability after being stretched 5000 times.In order to meet the growing need for smart bionic devices and epidermal electronic systems, biaxial stretchability is essential for energy storage units. Based on porous single-walled carbon nanotube/poly(3,4-ethylenedioxythiophene) (SWCNT/PEDOT) hybrid fiber, we designed and fabricated a biaxially stretchable supercapacitor, which possesses a unique configuration of the parallel buckled hybrid fiber array. Owing to the reticulate SWCNT film and the improved fabrication technique, the hybrid fiber retained its porous architecture both outwardly and inwardly, manifesting a superior capacity of 215 F g-1. H3PO4-polyvinyl alcohol gel with an optimized component ratio was introduced as both binder and stretchable electrolyte, which contributed to the regularity and stability of the buckled fiber array. The buckled structure and the quasi one-dimensional character of the

  16. 3D integral imaging using diffractive Fresnel lens arrays.

    PubMed

    Hain, Mathias; von Spiegel, Wolff; Schmiedchen, Marc; Tschudi, Theo; Javidi, Bahram

    2005-01-10

    We present experimental results with binary amplitude Fresnel lens arrays and binary phase Fresnel lens arrays used to implement integral imaging systems. Their optical performance is compared with high quality refractive microlens arrays and pinhole arrays in terms of image quality, color distortion and contrast. Additionally, we show the first experimental results of lens arrays with different focal lengths in integral imaging, and discuss their ability to simultaneously increase both the depth of focus and the field of view.

  17. Hybrid Pixel Detectors for gamma/X-ray imaging

    NASA Astrophysics Data System (ADS)

    Hatzistratis, D.; Theodoratos, G.; Zografos, V.; Kazas, I.; Loukas, D.; Lambropoulos, C. P.

    2015-09-01

    Hybrid pixel detectors are made by direct converting high-Z semi-insulating single crystalline material coupled to complementary-metal-oxide semiconductor (CMOS) readout electronics. They are attractive because direct conversion exterminates all the problems of spatial localization related to light diffusion, energy resolution, is far superior from the combination of scintillation crystals and photomultipliers and lithography can be used to pattern electrodes with very fine pitch. We are developing 2-D pixel CMOS ASICs, connect them to pixilated CdTe crystals with the flip chip and bump bonding method and characterize the hybrids. We have designed a series of circuits, whose latest member consists of a 50×25 pixel array with 400um pitch and an embedded controller. In every pixel a full spectroscopic channel with time tagging information has been implemented. The detectors are targeting Compton scatter imaging and they can be used for coded aperture imaging too. Hybridization using CMOS can overcome the limit put on pixel circuit complexity by the use of thin film transistors (TFT) in large flat panels. Hybrid active pixel sensors are used in dental imaging and other applications (e.g. industrial CT etc.). Thus X-ray imaging can benefit from the work done on dynamic range enhancement methods developed initially for visible and infrared CMOS pixel sensors. A 2-D CMOS ASIC with 100um pixel pitch to demonstrate the feasibility of such methods in the context of X-ray imaging has been designed.

  18. 10 and 20 micron imaging with arrays

    NASA Technical Reports Server (NTRS)

    Jones, B.; Pina, R. K.; Puetter, R. C.

    1994-01-01

    We discuss imaging with arrays in the thermal IR. Aspects of the design and performance of the 'Golden Gopher', an infrared array camera are presented. This instrument operates in a high-background environment, for ground-based astronomical imaging from 5 to 27 micrometers. It is built around a 20 x 64 element Si:As Impurity Band Conduction (IBC) device manufactured by GenCorp Aerojet Electronic Systems Division, and has a noise-equivalent flux density (NEFD) of 23.5 mJy (min(exp -1/2) (arcsec(exp -2) at lambda = 10 micrometers, delta-lambda = 1 micrometer, on the Mt. Lemmon 1.5m telescope. We present and discuss a sample of the data. In addition we discuss the design and expected performance of the 'Long Wavelength Spectrometer' which is now under construction for the Keck telescope.

  19. Imaging composite material using ultrasonic arrays

    NASA Astrophysics Data System (ADS)

    Li, Chuan; Pain, Damien; Wilcox, Paul D.; Drinkwater, Bruce W.

    2012-05-01

    This article describes an experimental procedure for improving the detectability of small defects in composite laminates based on modifications to the total focusing method (TFM) of processing ultrasonic array data to form an image. The TFM is modified to include the directional dependence of ultrasonic velocity. The maximum aperture angle is limited and a Gaussian frequency-domain filter is applied prior to processing. The parameters of maximum aperture angle, filter centre frequency and filter bandwidth are optimized.

  20. Efficient imaging techniques using an ultrasonic array

    NASA Astrophysics Data System (ADS)

    Moreau, L.; Hunter, A. J.; Drinkwater, B. W.; Wilcox, P. D.

    2010-03-01

    Over the past few years, ultrasonic phased arrays have shown good potential for non-destructive testing (NDT), thanks to high resolution imaging algorithms that allow the characterization of defects in a structure. Many algorithms are based on the full matrix capture, obtained by firing each element of an ultrasonic array independently, while collecting the data with all elements. Because of the finite sound velocity in the specimen, two consecutive firings must be separated by a minimum time interval. Therefore, more elements in the array require longer data acquisition times. Moreover, if the array has N elements, then the full matrix contains N2 temporal signals to be processed. Because of the limited calculation speed of current computers, a large matrix of data can result in rather long post-processing times. In an industrial context where real-time imaging is desirable, it is crucial to reduce acquisition and/or post-processing times. This paper investigates methods designed to reduce acquisition and post-processing times for the TFM and wavenumber algorithms. To reduce data capture and post-processing, limited transmission cycles are used. Post-processing times is also further reduced by demodulating the data to baseband, which allows reducing the sampling rate of signals. Results are presented so that a compromise can be made between acquisition time, post-processing time and image quality. Possible improvement of images quality, using the effective aperture theory, is discussed. This has been implemented for the TFM but it still has to be developed for the wavenumber algorithm.

  1. C-scan transmission ultrasound based on a hybrid microelectronic sensor array and its physical performance

    NASA Astrophysics Data System (ADS)

    Lo, Shih-Chung B.; Rich, David; Lasser, Marvin E.; Kula, John; Zhao, Hui; Lasser, Bob; Freedman, Matthew T.

    2001-05-01

    A C-scan through-transmission ultrasound system has been constructed based on a patented hybrid microelectronic array that is capable of generating ultrasound images with fluoroscopic presentation. To generate real-time images, ultrasound is introduced into the object under study with a large unfocused plane wave source. The resultant pressure wave strikes the object and is attenuated and scattered. The device detects scattered as well as attenuated ultrasound energy which allows the use of an acoustic lens to focus on detected energy from an object plane. The acoustic lens collects the transmitted energy and focuses it onto the ultrasound sensitive array. The array is made up to two components, a silicon detector/readout array and a piezoelectric material that is deposited onto the array through semiconductor processing. The array is 1 cm on a side consisting of 128x128 pixel elements with 85micrometers pixel spacing. The energy that strikes the piezoelectric material is converted to an analog voltage that is digitized and processed by low cost commercial video electronics. The images generated by the device appear with no speckle artifact with fluoroscopy-like presentation. The images show no obvious geometrical distortion. The experimental results indicated that the system has a spatial resolution of 0.32 mm. It can resolve 3mm objects with low differential contrast and an attenuation coefficient difference less than 0.07 dB/cm/MHz. Phase contrast of the objects are also clearly measurable. A presentation of a C- scan image guided breast biopsy was demonstrated. In addition, punctured needle tracks in a tumor was clearly observed. This implies the potential of observing the spiculation of masses in vivo.

  2. Infrared imaging of high density protein arrays.

    PubMed

    De Meutter, Joëlle; Vandenameele, Julie; Matagne, André; Goormaghtigh, Erik

    2017-04-10

    We propose in this paper that protein microarrays could be analysed by infrared imaging in place of enzymatic or fluorescence labelling. This label-free method reports simultaneously a large series of data on the spotted sample (protein secondary structure, phosphorylation, glycosylation, presence of impurities, etc.). In the present work, 100 μm protein spots each containing about 100 pg protein were deposited to form high density regular arrays. Using arrays of infrared detectors, high resolution images could be obtained where each pixel of the image is in fact a full infrared spectrum. With microarrays, hundreds of experimental conditions can be tested easily and quickly, with no further labelling or chemistry of any kind. We describe how the noise present in the infrared spectra can be split into image noise and detector noise. We also detail how both types of noise can be most conveniently dealt with to generate very high quality spectra of less than 100 pg protein. Finally, the results suggest that the protein secondary structure is preserved during microarray building.

  3. Indium Hybridization of Large Format TES Bolometer Arrays to Readout Multiplexers for Far-Infrared Astronomy

    NASA Technical Reports Server (NTRS)

    Miller, Timothy M.; Costen, Nick; Allen, Christine

    2007-01-01

    This conference poster reviews the Indium hybridization of the large format TES bolometer arrays. We are developing a key technology to enable the next generation of detectors. That is the Hybridization of Large Format Arrays using Indium bonded detector arrays containing 32x40 elements which conforms to the NIST multiplexer readout architecture of 1135 micron pitch. We have fabricated and hybridized mechanical models with the detector chips bonded after being fully back-etched. The mechanical support consists of 30 micron walls between elements Demonstrated electrical continuity for each element. The goal is to hybridize fully functional array of TES detectors to NIST readout.

  4. Development of a 1K x 1K GaAs QWIP Far IR Imaging Array

    NASA Technical Reports Server (NTRS)

    Jhabvala, M.; Choi, K.; Goldberg, A.; La, A.; Gunapala, S.

    2003-01-01

    In the on-going evolution of GaAs Quantum Well Infrared Photodetectors (QWIPs) we have developed a 1,024 x 1,024 (1K x1K), 8.4-9 microns infrared focal plane array (FPA). This 1 megapixel detector array is a hybrid using the Rockwell TCM 8050 silicon readout integrated circuit (ROIC) bump bonded to a GaAs QWIP array fabricated jointly by engineers at the Goddard Space Flight Center (GSFC) and the Army Research Laboratory (ARL). The finished hybrid is thinned at the Jet Propulsion Lab. Prior to this development the largest format array was a 512 x 640 FPA. We have integrated the 1K x 1K array into an imaging camera system and performed tests over the 40K-90K temperature range achieving BLIP performance at an operating temperature of 76K (f/2 camera system). The GaAs array is relatively easy to fabricate once the superlattice structure of the quantum wells has been defined and grown. The overall arrays costs are currently dominated by the costs associated with the silicon readout since the GaAs array fabrication is based on high yield, well-established GaAs processing capabilities. In this paper we will present the first results of our 1K x 1K QWIP array development including fabrication methodology, test data and our imaging results.

  5. Fast speed MWIR imager for uncooled focal plane array

    NASA Astrophysics Data System (ADS)

    Lin, Liu

    2007-12-01

    Recent advances of uncooled detector technology especially the development of uncooled micro-bolometer array hold promise for us to develop low-cost and compact MWIR earth observation imager. For comparative lower radiometric performance of uncooled focal plane array, fast speed optical system operating in large spectral bands is compatible. In addition, in order to exhibit advantages over imagers based on cooled detector technology, the optical system should be as compact as possible which means fewer elements, smaller size and light weight. In this article, a high speed optical design meeting these requirement is provided with 100mm focal length, F/1 F number,+/-2.5°field of view woking in 3-5um wave band. The fast speed MWIR imager has properties mentioned as follows: First, the optical system utilizes a hybrid system including refractive and diffractive elements. Second, the optical system realizes athermalization in simple passive way through distributing power among the refractive elements. It can work under typical temperature scope from -20°C to 60°C for typical space application. Third, Because of high speed aperture, the design makes use of aspheric surface to correct spherical aberration and spherochromatism .Finally, we use Ge and Si material. instead of expensive ZnS material.

  6. Polychromatic microarrays: simultaneous multicolor array hybridization of eight samples.

    PubMed

    Shepard, Jason R E

    2006-04-15

    High-throughput microscale platforms have transformed modern analytical investigations. Traditional microarray analyses involve a comparative approach, with two samples, a known control and an unknown sample, hybridized side-by-side and then contrasted for genetic differences. The samples are labeled with separate dyes and hybridized together, providing a differential expression pattern based on the reporter intensities. In contrast, the fiber-optic microarray platform described herein is analyzed with a microscope, thereby enabling the use of virtually any reporter, including quantum dots. The instrumentation takes advantage of the narrow emission bands characteristic of quantum dots to perform multiplexed detection of Bacillus anthracis. Advancing beyond the standard red/green microarray experiment, a panel of eight reporters were linked to eight B. anthracis samples and simultaneously analyzed in a microarray format. The ability to employ an assortment of reporters, along with the capacity to simultaneously hybridize eight samples confers an unprecedented flexibility to array-based analyses, providing a 4-fold increase in throughput over standard two-color assays.

  7. Sparsely-Bonded CMOS Hybrid Imager

    NASA Technical Reports Server (NTRS)

    Cunningham, Thomas J. (Inventor); Hancock, Bruce R. (Inventor); Sun, Chao (Inventor); Jones, Todd J. (Inventor); Dickie, Matthew R. (Inventor); Nikzad, Shouleh (Inventor); Hoenk, Michael E. (Inventor); Wrigley, Christopher J. (Inventor); Newton, Kenneth W. (Inventor); Pain, Bedabrata (Inventor)

    2015-01-01

    A method and device for imaging or detecting electromagnetic radiation is provided. A device structure includes a first chip interconnected with a second chip. The first chip includes a detector array, wherein the detector array comprises a plurality of light sensors and one or more transistors. The second chip includes a Read Out Integrated Circuit (ROIC) that reads out, via the transistors, a signal produced by the light sensors. A number of interconnects between the ROIC and the detector array can be less than one per light sensor or pixel.

  8. Polarization in a snap: imaging polarimetry with micropolarizer arrays

    NASA Astrophysics Data System (ADS)

    Vorobiev, Dmitry; Ninkov, Zoran; Gartley, Michael

    2014-05-01

    Polarization, flux, and the spectral energy distribution of light are the fundamental parameters that we measure in order to infer properties of the sources of electromagnetic radiation, such as intensity, temperature, chemical composition and physical geometry. Recently, the fabrication of microgrid polarizer arrays (MPAs) facilitated the development of a new class of division-of-focal plane polarimeters. These devices are capable of measuring the degree and angle of polarization across a scene with a single exposure. We present the design of the Rochester Institute of Technology Polarization Imaging Camera (RITPIC), a snapshot polarimeter for visible and near-infrared remote sensing applications. RITPIC is a compact, light-weight and mechanically robust imaging polarimeter that is deployable on terrestrial, naval, airborne and space-based platforms. RITPIC is developed using commercially available components and is capable of fast cadence imaging polarimetry of a wide variety of scenes. We derive the expected performance of RITPIC using the first high resolution 3D finite-difference time-domain (FDTD) models of these hybrid focal planes and simulated observations of synthetic scenes rendered with the Digital Imaging and Remote Sensing Image Generation (DIRSIG) model. Furthermore, we explore applications in remote sensing for which RITPIC, and devices like it, provide unique advantages.

  9. PHASED ARRAY FEED CALIBRATION, BEAMFORMING, AND IMAGING

    SciTech Connect

    Landon, Jonathan; Elmer, Michael; Waldron, Jacob; Jones, David; Stemmons, Alan; Jeffs, Brian D.; Warnick, Karl F.; Richard Fisher, J.; Norrod, Roger D.

    2010-03-15

    Phased array feeds (PAFs) for reflector antennas offer the potential for increased reflector field of view and faster survey speeds. To address some of the development challenges that remain for scientifically useful PAFs, including calibration and beamforming algorithms, sensitivity optimization, and demonstration of wide field of view imaging, we report experimental results from a 19 element room temperature L-band PAF mounted on the Green Bank 20 Meter Telescope. Formed beams achieved an aperture efficiency of 69% and a system noise temperature of 66 K. Radio camera images of several sky regions are presented. We investigate the noise performance and sensitivity of the system as a function of elevation angle with statistically optimal beamforming and demonstrate cancelation of radio frequency interference sources with adaptive spatial filtering.

  10. Improving the geometric fidelity of imaging systems employing sensor arrays

    NASA Technical Reports Server (NTRS)

    Jones, Kenneth L. (Inventor)

    1990-01-01

    A sensor assembly to be carried on an aircraft or spacecraft which will travel along an arbitrary flight path, for providing an image of terrain over which the craft travels, is disclosed. The assembly includes a main linear sensor array and a plurality of auxiliary sensor arrays oriented parallel to, and at respectively different distances from, the main array. By comparing the image signals produced by the main sensor array with those produced by each auxiliary array, information relating to variations in velocity of the craft carrying the assembly can be obtained. The signals from each auxiliary array will provide information relating to a respectively different frequency range.

  11. Imaging MAMA detector systems. [Multi-Anode Microchannel Array

    NASA Technical Reports Server (NTRS)

    Slater, David C.; Timothy, J. G.; Morgan, Jeffrey S.; Kasle, David B.

    1990-01-01

    Imaging multianode microchannel array (MAMA) detector systems with 1024 x 1024 pixel formats have been produced for visible and UV wavelengths; the UV types employ 'solar blind' photocathodes whose detective quantum efficiencies are significantly higher than those of currently available CCDs operating at far-UV and EUV wavelengths. Attention is presently given to the configurations and performance capabilities of state-of-the-art MAMA detectors, with a view to the development requirements of the hybrid electronic circuits needed for forthcoming spacecraft-sensor applications. Gain, dark noise, uniformity, and dynamic range performance data are presented for the curved-channel 'chevron', 'Z-plate', and helical-channel high gain microchannel plate configurations that are currently under evaluation with MAMA detector systems.

  12. Developments and Applications of High-Performance CCD and CMOS Imaging Arrays

    NASA Astrophysics Data System (ADS)

    Janesick, James; Putnam, Gloria

    2003-12-01

    For over 20 years, charge-coupled devices (CCDs) have dominated most digital imaging applications and markets. Today, complementary metal oxide semiconductor (CMOS) arrays are displacing CCDs in some applications, and this trend is expected to continue. Low cost, low power, on-chip system integration, and high-speed operation are unique features that have generated interest in CMOS arrays. This paper reviews current CCD and CMOS sensor developments and related applications. We compare fundamental performance parameters common to these technologies and describe why the CCD is considered a mature technology, whereas CMOS arrays have significant room for growth. The paper presents custom CMOS pixel designs and related fabrication processes that address performance deficiencies of the CCD in high-performance applications. We discuss areas of development for future CCD and CMOS imagers. The paper also briefly reviews hybrid imaging arrays that combine the advantages of CCD and CMOS, producing better sensors than either technology alone can provide.

  13. Hybrid-integrated prism array optoelectronic targeting system

    NASA Astrophysics Data System (ADS)

    Chang, C. C.; Chang, H. C.; Tang, L. C.; Young, W. K.; Wang, J. C.; Huang, K. L.

    2005-11-01

    This investigation proposes a cost-effective, compact, and robust optoelectronic targeting system for measuring ballistic impact velocity and the distribution of projectile motion. The major elements of this system are four photo-gates hybridized by compound one-dimensional prism array and analog/digital electronic components. The number of light sources and photodetectors used in a photo-gate was reduced to one pair of light source and photodetector. The average velocity and location of the projectile are determined according to the measured time intervals ( ˜10 -8 s) passing each pair. The system can accurately measure the velocity of a bullet as it leaves a gun barrel, as well as the velocity at specific points along the trajectory outside the firearm. Additionally, the system uses a widespread low-powered laser pointer as a light source. Compared with other optoelectronic targeting systems that use high-powered lasers, the proposed system is both economical and safe.

  14. Dark Field Imaging of Plasmonic Resonator Arrays

    NASA Astrophysics Data System (ADS)

    Aydinli, Atilla; Balci, Sinan; Karademir, Ertugrul; Kocabas, Coskun

    2012-02-01

    We present critical coupling of electromagnetic waves to plasmonic cavity arrays fabricated on Moir'e surfaces. The critical coupling condition depends on the superperiod of Moir'e surface, which also defines the coupling between the cavities. Complete transfer of the incident power can be achieved for traveling wave plasmonic resonators, which have relatively short superperiod. When the superperiod of the resonators increases, the coupled resonators become isolated standing wave resonators in which complete transfer of the incident power is not possible. Dark field plasmon microscopy imaging and polarization dependent spectroscopic reflection measurements reveal the critical coupling conditions of the cavities. We image the light scattered from SPPs in the plasmonic cavities excited by a tunable light source. Tuning the excitation wavelength, we measure the localization and dispersion of the plasmonic cavity mode. Dark field imaging has been achieved in the Kretschmann configuration using a supercontinuum white light laser equipped with an acoustooptic tunable filter. Polarization dependent spectroscopic reflection and dark field imaging measurements are correlated and found to be in agreement with FDTD simulations.

  15. CCD/CMOS hybrid FPA for low light level imaging

    NASA Astrophysics Data System (ADS)

    Liu, Xinqiao; Fowler, Boyd A.; Onishi, Steve K.; Vu, Paul; Wen, David D.; Do, Hung; Horn, Stuart

    2005-08-01

    We present a CCD / CMOS hybrid focal plane array (FPA) for low light level imaging applications. The hybrid approach combines the best of CCD imaging characteristics (e.g. high quantum efficiency, low dark current, excellent uniformity, and low pixel cross talk) with the high speed, low power and ultra-low read noise of CMOS readout technology. The FPA is comprised of two CMOS readout integrated circuits (ROIC) that are bump bonded to a CCD imaging substrate. Each ROIC is an array of Capacitive Transimpedence Amplifiers (CTIA) that connect to the CCD columns via indium bumps. The proposed column parallel readout architecture eliminates the slow speed, high noise, and high power limitations of a conventional CCD. This results in a compact, low power, ultra-sensitive solid-state FPA that can be used in low light level applications such as live-cell microscopy and security cameras at room temperature operation. The prototype FPA has a 1280×1024 format with 12-um square pixels. Measured dark current is less than 5.8 pA/cm2 at room temperature and the overall read noise is as low as 2.9e at 30 frames/sec.

  16. Reconstruction Techniques for Sparse Multistatic Linear Array Microwave Imaging

    SciTech Connect

    Sheen, David M.; Hall, Thomas E.

    2014-06-09

    Sequentially-switched linear arrays are an enabling technology for a number of near-field microwave imaging applications. Electronically sequencing along the array axis followed by mechanical scanning along an orthogonal axis allows dense sampling of a two-dimensional aperture in near real-time. In this paper, a sparse multi-static array technique will be described along with associated Fourier-Transform-based and back-projection-based image reconstruction algorithms. Simulated and measured imaging results are presented that show the effectiveness of the sparse array technique along with the merits and weaknesses of each image reconstruction approach.

  17. Hybrid Compton camera/coded aperture imaging system

    DOEpatents

    Mihailescu, Lucian [Livermore, CA; Vetter, Kai M [Alameda, CA

    2012-04-10

    A system in one embodiment includes an array of radiation detectors; and an array of imagers positioned behind the array of detectors relative to an expected trajectory of incoming radiation. A method in another embodiment includes detecting incoming radiation with an array of radiation detectors; detecting the incoming radiation with an array of imagers positioned behind the array of detectors relative to a trajectory of the incoming radiation; and performing at least one of Compton imaging using at least the imagers and coded aperture imaging using at least the imagers. A method in yet another embodiment includes detecting incoming radiation with an array of imagers positioned behind an array of detectors relative to a trajectory of the incoming radiation; and performing Compton imaging using at least the imagers.

  18. Novel Nonlinear Hybrid Filters for Image Enhancement

    NASA Astrophysics Data System (ADS)

    Peng, Shaomin

    1995-01-01

    Image noise removal and enhancement are important subjects in image processing. Nonlinear techniques for image enhancement and noise reduction challenge the linear techniques by improving image quality while removing noise. The purpose of this thesis is devoted to systematically unifying theory and techniques for mixed noise removal and image enhancement, and to developing new techniques for removing large amounts of mixed Gaussian and impulsive noise while preserving image details. In this thesis, we introduce three new hybrid filters which combine linear and nonlinear filters to produce new hybrid filters capable of removing large amounts of mixed noise. To efficiently use the ambiguous information in an image, both fuzzy set concepts and fuzzy logic operating rules are utilized in the filter design techniques. The three new filters include the single level trained fuzzy filter (SLTF), the multi-level adaptive fuzzy filter (MLAF), and the decision directed window adaptive hybrid filter (DDWAH). The SLTF filter is designed to remove large amounts of mixed noise by combining an impulse filter with a fuzzy filter. The efficiency of the SLTF filter in removing large amounts of mixed noise while preserving image edges is demonstrated. The MLAF filter is an adaptive SLTF filter which uses the local variance of image gray scales to adapt the weights used in the linear portion of the filter to local image statistics. The MLAF filter provides improved visual performance compared to the SLTF filter. The adaptive DDWAH filter uses local statistics to adapt the window size of the filter to local statistics. This approach prevents distortion of small objects in the image, and removes noise more effectively than non-adaptive filters. The experimental results clearly show the improved noise removal performance and good edge preservation properties. Theoretical analysis verifies the measured results.

  19. Imaging Prostate Cancer Microenvironment by Collagen Hybridization

    DTIC Science & Technology

    2015-10-01

    INVESTIGATOR: Dr. Michael S. Yu CONTRACTING ORGANIZATION: University of Utah Salt Lake City, UT 84112 REPORT DATE: October 2015 TYPE OF REPORT: Annual...SUBTITLE Imaging Prostate Cancer Microenvironment by Collagen Hybridization 5a. CONTRACT NUMBER 5b. GRANT NUMBER W81XWH-12-1-0555 5c. PROGRAM ELEMENT...peptide (CMP) as a collagen targeting agents that will allow imaging of invasive PCa. Since CMP binds to unstructured collagens more readily, it is

  20. A hybrid technique for medical image segmentation.

    PubMed

    Nyma, Alamgir; Kang, Myeongsu; Kwon, Yung-Keun; Kim, Cheol-Hong; Kim, Jong-Myon

    2012-01-01

    Medical image segmentation is an essential and challenging aspect in computer-aided diagnosis and also in pattern recognition research. This paper proposes a hybrid method for magnetic resonance (MR) image segmentation. We first remove impulsive noise inherent in MR images by utilizing a vector median filter. Subsequently, Otsu thresholding is used as an initial coarse segmentation method that finds the homogeneous regions of the input image. Finally, an enhanced suppressed fuzzy c-means is used to partition brain MR images into multiple segments, which employs an optimal suppression factor for the perfect clustering in the given data set. To evaluate the robustness of the proposed approach in noisy environment, we add different types of noise and different amount of noise to T1-weighted brain MR images. Experimental results show that the proposed algorithm outperforms other FCM based algorithms in terms of segmentation accuracy for both noise-free and noise-inserted MR images.

  1. Imaging Using Energy Discriminating Radiation Detector Array

    SciTech Connect

    Willson, Paul D.; Clajus, Martin; Tuemer, Tuemay O.; Visser, Gerard; Cajipe, Victoria

    2003-08-26

    Industrial X-ray radiography is often done using a broad band energy source and always a broad band energy detector. There exist several major advantages in the use of narrow band sources and or detectors, one of which is the separation of scattered radiation from primary radiation. ARDEC has developed a large detector array system in which every detector element acts like a multi-channel analyzer. A radiographic image is created from the number of photons detected in each detector element, rather than from the total energy absorbed in the elements. For high energies, 25 KeV to 4 MeV, used in radiography, energy discriminating detectors have been limited to less than 20,000 photons per second per detector element. This rate is much too slow for practical radiography. Our detector system processes over two million events per second per detector pixel, making radiographic imaging practical. This paper expounds on the advantages of the ARDEC radiographic imaging process.

  2. Design of Hybrid Nanostructural Arrays to Manipulate SERS-Active Substrates by Nanosphere Lithography.

    PubMed

    Zhao, Xiaoyu; Wen, Jiahong; Zhang, Mengning; Wang, Dunhui; Wang, Yaxin; Chen, Lei; Zhang, Yongjun; Yang, Jinghai; Du, Youwei

    2017-03-01

    An easy-handling and low-cost method is utilized to controllably fabricate nanopattern arrays as the surface-enhanced Raman scattering (SERS) active substrates with high density of SERS-active areas (hot spots). A hybrid silver array of nanocaps and nanotriangles are prepared by combining magnetron sputtering and plasma etching. By adjusting the etching time of polystyrene (PS) colloid spheres array in silver nanobowls, the morphology of the arrays can be easily manipulated to control the formation and distribution of hot spots. The experimental results show that the hybrid nanostructural arrays have large enhancement factor, which is estimated to be seven times larger than that in the array of nanocaps and three times larger than that in the array of nanorings and nanoparticles. According to the results of finite-difference time-domain simulation, the excellent SERS performance of this array is ascribed to the high density of hot spots and enhanced electromagnetic field.

  3. A 58 x 62 pixel Si:Ga array camera for 5 - 14 micron astronomical imaging

    NASA Technical Reports Server (NTRS)

    Gezari, D. Y.; Folz, W. C.; Woods, L. A.; Wooldridge, J. B.

    1989-01-01

    A new infrared array camera system has been successfully applied to high background 5 - 14 micron astronomical imaging photometry observations, using a hybrid 58 x 62 pixel Si:Ga array detector. The off-axis reflective optical design incorporating a parabolic camera mirror, circular variable filter wheel, and cold aperture stop produces diffraction-limited images with negligible spatial distortion and minimum thermal background loading. The camera electronic system architecture is divided into three subsystems: (1) high-speed analog front end, including 2-channel preamp module, array address timing generator, bias power suppies, (2) two 16 bit, 3 microsec per conversion A/D converters interfaced to an arithmetic array processor, and (3) an LSI 11/73 camera control and data analysis computer. The background-limited observational noise performance of the camera at the NASA/IRTF telescope is NEFD (1 sigma) = 0.05 Jy/pixel min exp 1/2.

  4. Optical Imaging of Water Condensation on Lubricant Impregnated Micropillar Arrays

    NASA Astrophysics Data System (ADS)

    Kajiya, Tadashi; Schellenberger, Frank; Papadopoulos, Periklis; Vollmer, Doris; Butt, Hans-Jürgen

    2015-11-01

    We explored the condensation of water drops on a lubricant-impregnated surface, i.e., a micropillar patterned surface impregnated with a ionic liquid. Growing drops were imaged in 3D using a laser scanning confocal microscope equipped with a temperature and humidity control. On a lubricant-impregnated hydrophobic micropillar array, different stages of condensation can be discriminated: - Nucleation on a lubricant surface. - Regular alignement between micropillars and formation of a three-phase contact line on a bottom of the substrate. - Deformation and bridging by coalescence, leading to a detachment of the drops from the bottom substrate to pillars'top faces. However, on a lubricant-impregnated hydrophilic micropillar array, the condensed water covers the micropillars by dewetting the lubricant. As a result, the surface loses its slippery property. Our results provide fundamental concepts how these solid/liquid hybrid surfaces can be applied for facile removal of condensed water, as well as necessity of the appropriate surface treatment. Financial support from ERC for the advanced grant 340391-SUPRO is gratefully acknowledged.

  5. 7T human spine imaging arrays with adjustable inductive decoupling.

    PubMed

    Wu, Bing; Wang, Chunsheng; Krug, Roland; Kelley, Douglas A; Xu, Duan; Pang, Yong; Banerjee, Suchandrima; Vigneron, Daniel B; Nelson, Sarah J; Majumdar, Sharmila; Zhang, Xiaoliang

    2010-02-01

    Ultrahigh-field human spine RF transceiver coil arrays face daunting technical challenges in achieving large imaging coverage with sufficient B(1) penetration and sensitivity, and in attaining robust decoupling among coil elements. In this paper, human spine coil arrays for ultrahigh field were built and studied. Transceiver arrays with loop-shaped microstrip transmission line were designed, fabricated, and tested for 7-tesla (7T) MRI. With the proposed adjustable inductive decoupling technique, the isolation between adjacent coil elements is easily addressed. Preliminary results of human spine images acquired using the transceiver arrays demonstrate the feasibility of the design for ultrahigh-field MR applications and its robust performance for parallel imaging.

  6. Digital image processing software system using an array processor

    SciTech Connect

    Sherwood, R.J.; Portnoff, M.R.; Journeay, C.H.; Twogood, R.E.

    1981-03-10

    A versatile array processor-based system for general-purpose image processing was developed. At the heart of this system is an extensive, flexible software package that incorporates the array processor for effective interactive image processing. The software system is described in detail, and its application to a diverse set of applications at LLNL is briefly discussed. 4 figures, 1 table.

  7. Si/PEDOT hybrid core/shell nanowire arrays as photoelectrodes for photoelectrochemical water-splitting

    NASA Astrophysics Data System (ADS)

    Li, Xiaojuan; Lu, Wenhui; Dong, Weiling; Chen, Qi; Wu, Dan; Zhou, Wenzheng; Chen, Liwei

    2013-05-01

    Si/poly(3,4-ethylenedioxythiophene) (PEDOT) core/shell nanowire arrays have been prepared by chemical etching of Si nanowires followed by vapor-phase polymerization of PEDOT as hybrid photoanodes for photoelectrochemical water-splitting. The PEDOT layer is employed as a multi-functional coating to prevent photocorrosion of Si nanowires, collect photogenerated holes and catalyze the water oxidation reaction. The amino silane modified Si nanowire surface improves PEDOT layer adhesion, and the resulting photoanode exhibits better photoresponse and improved stability. By tuning the length of the nanowires, we identify that the competition between the carrier recombination and catalytic water oxidation reaction is the primary factor determining the photoelectrocatalytic activity of the hybrid photoanode.Si/poly(3,4-ethylenedioxythiophene) (PEDOT) core/shell nanowire arrays have been prepared by chemical etching of Si nanowires followed by vapor-phase polymerization of PEDOT as hybrid photoanodes for photoelectrochemical water-splitting. The PEDOT layer is employed as a multi-functional coating to prevent photocorrosion of Si nanowires, collect photogenerated holes and catalyze the water oxidation reaction. The amino silane modified Si nanowire surface improves PEDOT layer adhesion, and the resulting photoanode exhibits better photoresponse and improved stability. By tuning the length of the nanowires, we identify that the competition between the carrier recombination and catalytic water oxidation reaction is the primary factor determining the photoelectrocatalytic activity of the hybrid photoanode. Electronic supplementary information (ESI) available: The schematic setup of photoelectrochemical performance tests, and the SEM images of different photoanodes before and after photoelectrochemical tests. See DOI: 10.1039/c3nr00867c

  8. Fabricating a hybrid imaging device having non-destructive sense nodes

    NASA Technical Reports Server (NTRS)

    Wadsworth, Mark (Inventor); Atlas, Gene (Inventor)

    2001-01-01

    A hybrid detector or imager includes two substrates fabricated under incompatible processes. An array of detectors, such as charged-coupled devices, are formed on the first substrate using a CCD fabrication process, such as a buried channel or peristaltic process. One or more charge-converting amplifiers are formed on a second substrate using a CMOS fabrication process. The two substrates are then bonded together to form a hybrid detector.

  9. Volumetric Real-Time Imaging Using a CMUT Ring Array

    PubMed Central

    Choe, Jung Woo; Oralkan, Ömer; Nikoozadeh, Amin; Gencel, Mustafa; Stephens, Douglas N.; O’Donnell, Matthew; Sahn, David J.; Khuri-Yakub, Butrus T.

    2012-01-01

    A ring array provides a very suitable geometry for forward-looking volumetric intracardiac and intravascular ultrasound imaging. We fabricated an annular 64-element capacitive micromachined ultrasonic transducer (CMUT) array featuring a 10-MHz operating frequency and a 1.27-mm outer radius. A custom software suite was developed to run on a PC-based imaging system for real-time imaging using this device. This paper presents simulated and experimental imaging results for the described CMUT ring array. Three different imaging methods—flash, classic phased array (CPA), and synthetic phased array (SPA)—were used in the study. For SPA imaging, two techniques to improve the image quality—Hadamard coding and aperture weighting—were also applied. The results show that SPA with Hadamard coding and aperture weighting is a good option for ring-array imaging. Compared with CPA, it achieves better image resolution and comparable signal-to-noise ratio at a much faster image acquisition rate. Using this method, a fast frame rate of up to 463 volumes per second is achievable if limited only by the ultrasound time of flight; with the described system we reconstructed three cross-sectional images in real-time at 10 frames per second, which was limited by the computation time in synthetic beamforming. PMID:22718870

  10. Synergistic image reconstruction for hybrid ultrasound and photoacoustic computed tomography

    NASA Astrophysics Data System (ADS)

    Matthews, Thomas P.; Wang, Kun; Wang, Lihong V.; Anastasio, Mark A.

    2015-03-01

    Conventional photoacoustic computed tomography (PACT) image reconstruction methods assume that the object and surrounding medium are described by a constant speed-of-sound (SOS) value. In order to accurately recover fine structures, SOS heterogeneities should be quantified and compensated for during PACT reconstruction. To address this problem, several groups have proposed hybrid systems that combine PACT with ultrasound computed tomography (USCT). In such systems, a SOS map is reconstructed first via USCT. Consequently, this SOS map is employed to inform the PACT reconstruction method. Additionally, the SOS map can provide structural information regarding tissue, which is complementary to the functional information from the PACT image. We propose a paradigm shift in the way that images are reconstructed in hybrid PACT-USCT imaging. Inspired by our observation that information about the SOS distribution is encoded in PACT measurements, we propose to jointly reconstruct the absorbed optical energy density and SOS distributions from a combined set of USCT and PACT measurements, thereby reducing the two reconstruction problems into one. This innovative approach has several advantages over conventional approaches in which PACT and USCT images are reconstructed independently: (1) Variations in the SOS will automatically be accounted for, optimizing PACT image quality; (2) The reconstructed PACT and USCT images will possess minimal systematic artifacts because errors in the imaging models will be optimally balanced during the joint reconstruction; (3) Due to the exploitation of information regarding the SOS distribution in the full-view PACT data, our approach will permit high-resolution reconstruction of the SOS distribution from sparse array data.

  11. A 5-18 micron array camera for high-background astronomical imaging

    NASA Technical Reports Server (NTRS)

    Gezari, Daniel Y.; Folz, Walter C.; Woods, Lawrence A.; Varosi, Frank

    1992-01-01

    A new infrared array camera system using a Hughes/SBRC 58 x 62 pixel hybrid Si:Ga array detector has been successfully applied to high-background 5-18-micron astronomical imaging observations. The off-axis reflective optical system minimizes thermal background loading and produces diffraction-limited images with negligible spatial distortion. The noise equivalent flux density (NEFD) of the camera at 10 microns on the 3.0-m NASA/Infrared Telescope Facility with broadband interference filters and 0.26 arcsec pixel is NEFD = 0.01 Jy/sq rt min per pixel (1sigma), and it operates at a frame rate of 30 Hz with no compromise in observational efficiency. The electronic and optical design of the camera, its photometric characteristics, examples of observational results, and techniques for successful array imaging in a high- background astronomical application are discussed.

  12. Si/PEDOT:PSS core/shell nanowire arrays for efficient hybrid solar cells.

    PubMed

    Lu, Wenhui; Wang, Chengwei; Yue, Wei; Chen, Liwei

    2011-09-01

    A solution filling and drying method has been demonstrated to fabricate Si/PEDOT:PSS core/shell nanowire arrays for hybrid solar cells. The hybrid core/shell nanowire arrays show excellent broadband anti-reflection, and resulting hybrid solar cells absorb about 88% of AM 1.5G photons in the 300-1100 nm range. The power conversion efficiency (PCE) of the hybrid solar cell reaches 6.35%, and is primarily limited by direct and indirect interfacial recombination of charge carriers.

  13. A Phased Array Coil for Human Cardiac Imaging

    PubMed Central

    Constantinides, Chris D.; Westgate, Charles R.; O'Dell, Walter G.; Zerhouni, Elias A.; McVeigh, Elliot R.

    2007-01-01

    A prototype cardiac phased array receiver coil was constructed that comprised a cylindrical array and a separate planar array. Both arrays had two coil loops with the same coil dimensions. Data acquisition with the cylindrical array placed on the human chest, and the planar array placed under the back, yielded an overall enhancement of the signal-to-noise ratio (SNR) over the entire heart by a factor of 1.1–2.85 over a commercially available flexible coil and a commercially available four-loop planar phased array coil. This improvement in SNR can be exploited in cardiac imaging to increase the spatial resolution and reduce the image acquisition time. PMID:7674903

  14. Reconstruction techniques for sparse multistatic linear array microwave imaging

    NASA Astrophysics Data System (ADS)

    Sheen, David M.; Hall, Thomas E.

    2014-06-01

    Sequentially-switched linear arrays are an enabling technology for a number of near-field microwave imaging applications. Electronically sequencing along the array axis followed by mechanical scanning along an orthogonal axis allows dense sampling of a two-dimensional aperture in near real-time. The Pacific Northwest National Laboratory (PNNL) has developed this technology for several applications including concealed weapon detection, groundpenetrating radar, and non-destructive inspection and evaluation. These techniques form three-dimensional images by scanning a diverging beam swept frequency transceiver over a two-dimensional aperture and mathematically focusing or reconstructing the data into three-dimensional images. Recently, a sparse multi-static array technology has been developed that reduces the number of antennas required to densely sample the linear array axis of the spatial aperture. This allows a significant reduction in cost and complexity of the linear-array-based imaging system. The sparse array has been specifically designed to be compatible with Fourier-Transform-based image reconstruction techniques; however, there are limitations to the use of these techniques, especially for extreme near-field operation. In the extreme near-field of the array, back-projection techniques have been developed that account for the exact location of each transmitter and receiver in the linear array and the 3-D image location. In this paper, the sparse array technique will be described along with associated Fourier-Transform-based and back-projection-based image reconstruction algorithms. Simulated imaging results are presented that show the effectiveness of the sparse array technique along with the merits and weaknesses of each image reconstruction approach.

  15. 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.

  16. Array comparative genomic hybridization analysis of olfactory neuroblastoma.

    PubMed

    Guled, Mohamed; Myllykangas, Samuel; Frierson, Henry F; Mills, Stacey E; Knuutila, Sakari; Stelow, Edward B

    2008-06-01

    Olfactory neuroblastoma is an unusual neuroectodermal malignancy, which is thought to arise at the olfactory membrane of the sinonasal tract. Due to its rarity, little is understood regarding its molecular and cytogenetic abnormalities. The aim of the current study is to identify specific DNA copy number changes in olfactory neuroblastoma. Thirteen dissected tissue samples were analyzed using array comparative genomic hybridization. Our results show that gene copy number profiles of olfactory neuroblastoma samples are complex. The most frequent changes included gains at 7q11.22-q21.11, 9p13.3, 13q, 20p/q, and Xp/q, and losses at 2q31.1, 2q33.3, 2q37.1, 6q16.3, 6q21.33, 6q22.1, 22q11.23, 22q12.1, and Xp/q. Gains were more frequent than losses, and high-stage tumors showed more alterations than low-stage olfactory neuroblastoma. Frequent changes in high-stage tumors were gains at 13q14.2-q14.3, 13q31.1, and 20q11.21-q11.23, and loss of Xp21.1 (in 66% of cases). Gains at 5q35, 13q, and 20q, and losses at 2q31.1, 2q33.3, and 6q16-q22, were present in 50% of cases. The identified regions of gene copy number change have been implicated in a variety of tumors, especially carcinomas. In addition, our results indicate that gains in 20q and 13q may be important in the progression of this cancer, and that these regions possibly harbor genes with functional relevance in olfactory neuroblastoma.

  17. Array comparative genomic hybridization in retinoma and retinoblastoma tissues.

    PubMed

    Sampieri, Katia; Amenduni, Mariangela; Papa, Filomena Tiziana; Katzaki, Eleni; Mencarelli, Maria Antonietta; Marozza, Annabella; Epistolato, Maria Carmela; Toti, Paolo; Lazzi, Stefano; Bruttini, Mirella; De Filippis, Roberta; De Francesco, Sonia; Longo, Ilaria; Meloni, Ilaria; Mari, Francesca; Acquaviva, Antonio; Hadjistilianou, Theodora; Renieri, Alessandra; Ariani, Francesca

    2009-03-01

    In retinoblastoma, two RB1 mutations are necessary for tumor development. Recurrent genomic rearrangements may represent subsequent events required for retinoblastoma progression. Array-comparative genomic hybridization was carried out in 18 eye samples, 10 from bilateral and eight from unilateral retinoblastoma patients. Two unilateral cases also showed areas of retinoma. The most frequent imbalance in retinoblastomas was 6p gain (40%), followed by gains at 1q12-q25.3, 2p24.3-p24.2, 9q22.2, and 9q33.1 and losses at 11q24.3, 13q13.2-q22.3, and 16q12.1-q21. Bilateral cases showed a lower number of imbalances than unilateral cases (P = 0.002). Unilateral cases were divided into low-level (< or = 4) and high-level (> or = 7) chromosomal instability groups. The first group presented with younger age at diagnosis (mean 511 days) compared with the second group (mean 1606 days). In one retinoma case ophthalmoscopically diagnosed as a benign lesion no rearrangements were detected, whereas the adjacent retinoblastoma displayed seven aberrations. The other retinoma case identified by retrospective histopathological examination shared three rearrangements with the adjacent retinoblastoma. Two other gene-free rearrangements were retinoma specific. One rearrangement, dup5p, was retinoblastoma specific and included the SKP2 gene. Genomic profiling indicated that the first retinoma was a pretumoral lesion, whereas the other represents a subclone of cells bearing 'benign' rearrangements overwhelmed by another subclone presenting aberrations with higher 'oncogenic' potential. In summary, the present study shows that bilateral and unilateral retinoblastoma have different chromosomal instability that correlates with the age of tumor onset in unilateral cases. This is the first report of genomic profiling in retinoma tissue, shedding light on the different nature of lesions named 'retinoma'.

  18. Phased Array Antenna Analysis Using Hybrid Finite Element Methods

    DTIC Science & Technology

    1993-06-01

    Waveguide ; (b) Geometry Model for Method of Moments ........................ 4 2. Printed Dipole Radiator: (a) Actual Geometry with Microstrip Balun and...Finite Elem ents . ............................................. 19 11. Equivalence Model for Waveguide /Cavity Problem: (a) Original Problem; (b... Waveguide Array Active Reflection Coefficient - Comparison of Results Uscig Cavity Array (CAVIARR) and General Array (PARANA) Models . 76 45. Rectangular

  19. Underwater Imaging Using a 1 × 16 CMUT Linear Array

    PubMed Central

    Zhang, Rui; Zhang, Wendong; He, Changde; Zhang, Yongmei; Song, Jinlong; Xue, Chenyang

    2016-01-01

    A 1 × 16 capacitive micro-machined ultrasonic transducer linear array was designed, fabricated, and tested for underwater imaging in the low frequency range. The linear array was fabricated using Si-SOI bonding techniques. Underwater transmission performance was tested in a water tank, and the array has a resonant frequency of 700 kHz, with pressure amplitude 182 dB (μPa·m/V) at 1 m. The −3 dB main beam width of the designed dense linear array is approximately 5 degrees. Synthetic aperture focusing technique was applied to improve the resolution of reconstructed images, with promising results. Thus, the proposed array was shown to be suitable for underwater imaging applications. PMID:26938536

  20. Photonic Doppler velocimetry lens array probe incorporating stereo imaging

    DOEpatents

    Malone, Robert M.; Kaufman, Morris I.

    2015-09-01

    A probe including a multiple lens array is disclosed to measure velocity distribution of a moving surface along many lines of sight. Laser light, directed to the moving surface is reflected back from the surface and is Doppler shifted, collected into the array, and then directed to detection equipment through optic fibers. The received light is mixed with reference laser light and using photonic Doppler velocimetry, a continuous time record of the surface movement is obtained. An array of single-mode optical fibers provides an optic signal to the multiple lens array. Numerous fibers in a fiber array project numerous rays to establish many measurement points at numerous different locations. One or more lens groups may be replaced with imaging lenses so a stereo image of the moving surface can be recorded. Imaging a portion of the surface during initial travel can determine whether the surface is breaking up.

  1. Visible light focusing flat lenses based on hybrid dielectric-metal metasurface reflector-arrays.

    PubMed

    Fan, Qingbin; Huo, Pengcheng; Wang, Daopeng; Liang, Yuzhang; Yan, Feng; Xu, Ting

    2017-03-23

    Conventional metasurface reflector-arrays based on metallic resonant nanoantenna to control the wavefront of light for focusing always suffer from strong ohmic loss at optical frequencies. Here, we overcome this challenge by constructing a non-resonant, hybrid dielectric-metal configuration consisting of TiO2 nanofins associated with an Ag reflector substrate that provides a broadband response and high polarization conversion efficiency in the visible range. A reflective flat lens based on this configuration shows an excellent focusing performance with the spot size close to the diffraction limit. Furthermore, by employing the superimposed phase distribution design to manipulate the wavefront of the reflected light, various functionalities, such as multifocal and achromatic focusing, are demonstrated for the flat lenses. Such a reflective flat lens will find various applications in visible light imaging and sensing systems.

  2. Visible light focusing flat lenses based on hybrid dielectric-metal metasurface reflector-arrays

    PubMed Central

    Fan, Qingbin; Huo, Pengcheng; Wang, Daopeng; Liang, Yuzhang; Yan, Feng; Xu, Ting

    2017-01-01

    Conventional metasurface reflector-arrays based on metallic resonant nanoantenna to control the wavefront of light for focusing always suffer from strong ohmic loss at optical frequencies. Here, we overcome this challenge by constructing a non-resonant, hybrid dielectric-metal configuration consisting of TiO2 nanofins associated with an Ag reflector substrate that provides a broadband response and high polarization conversion efficiency in the visible range. A reflective flat lens based on this configuration shows an excellent focusing performance with the spot size close to the diffraction limit. Furthermore, by employing the superimposed phase distribution design to manipulate the wavefront of the reflected light, various functionalities, such as multifocal and achromatic focusing, are demonstrated for the flat lenses. Such a reflective flat lens will find various applications in visible light imaging and sensing systems. PMID:28332611

  3. Visible light focusing flat lenses based on hybrid dielectric-metal metasurface reflector-arrays

    NASA Astrophysics Data System (ADS)

    Fan, Qingbin; Huo, Pengcheng; Wang, Daopeng; Liang, Yuzhang; Yan, Feng; Xu, Ting

    2017-03-01

    Conventional metasurface reflector-arrays based on metallic resonant nanoantenna to control the wavefront of light for focusing always suffer from strong ohmic loss at optical frequencies. Here, we overcome this challenge by constructing a non-resonant, hybrid dielectric-metal configuration consisting of TiO2 nanofins associated with an Ag reflector substrate that provides a broadband response and high polarization conversion efficiency in the visible range. A reflective flat lens based on this configuration shows an excellent focusing performance with the spot size close to the diffraction limit. Furthermore, by employing the superimposed phase distribution design to manipulate the wavefront of the reflected light, various functionalities, such as multifocal and achromatic focusing, are demonstrated for the flat lenses. Such a reflective flat lens will find various applications in visible light imaging and sensing systems.

  4. Role of Hybrid Brain Imaging in Neuropsychiatric Disorders

    PubMed Central

    Burhan, Amer M.; Marlatt, Nicole M.; Palaniyappan, Lena; Anazodo, Udunna C.; Prato, Frank S.

    2015-01-01

    This is a focused review of imaging literature to scope the utility of hybrid brain imaging in neuropsychiatric disorders. The review focuses on brain imaging modalities that utilize hybrid (fusion) techniques to characterize abnormal brain molecular signals in combination with structural and functional changes that have been observed in neuropsychiatric disorders. An overview of clinical hybrid brain imaging technologies for human use is followed by a selective review of the literature that conceptualizes the use of these technologies in understanding basic mechanisms of major neuropsychiatric disorders and their therapeutics. Neuronal network abnormalities are highlighted throughout this review to scope the utility of hybrid imaging as a potential biomarker for each disorder. PMID:26854172

  5. HOPIS: Hybrid Omnidirectional and Perspective Imaging System for Mobile Robots

    PubMed Central

    Lin, Huei-Yung.; Wang, Min-Liang.

    2014-01-01

    In this paper, we present a framework for the hybrid omnidirectional and perspective robot vision system. Based on the hybrid imaging geometry, a generalized stereo approach is developed via the construction of virtual cameras. It is then used to rectify the hybrid image pair using the perspective projection model. The proposed method not only simplifies the computation of epipolar geometry for the hybrid imaging system, but also facilitates the stereo matching between the heterogeneous image formation. Experimental results for both the synthetic data and real scene images have demonstrated the feasibility of our approach. PMID:25192317

  6. Inkjet-Printed Photodetector Arrays Based on Hybrid Perovskite CH3NH3PbI3 Microwires.

    PubMed

    Liu, Yang; Li, Fushan; Perumal Veeramalai, Chandrasekar; Chen, Wei; Guo, Tailiang; Wu, Chaoxing; Kim, Tae Whan

    2017-04-05

    Hybrid perovskite CH3NH3PbI3 has attracted extensive research interests in optoelectronic devices in recent years. Herein an inkjet printing method has been employed to deposit a perovskite CH3NH3PbI3 layer. By choosing the proper solvent and controlling the crystal growth rate, hybrid perovskite CH3NH3PbI3 nanowires, microwires, a network, and islands were synthesized by means of inkjet printing. Electrode-gap-electrode lateral-structured photodetectors were fabricated with these different crystals, of which a hybrid perovskite microwire-based photodetector would balance the uniformity and low defects to obtain a switching ratio of 16000%, responsivity of 1.2 A/W, and normalized detectivity of 2.39 × 10(12) Jones at a light power density of 0.1 mW/cm(2). Furthermore, the hybrid perovskite microwire-based photodetector arrays were fabricated and applied in an imaging sensor, from which the clear mapping of the light source signal was successfully obtained. This work paves the way for the realization of low-cost, solution-processed, and high-performance hybrid perovskite-based photodetector arrays.

  7. Vision communications based on LED array and imaging sensor

    NASA Astrophysics Data System (ADS)

    Yoo, Jong-Ho; Jung, Sung-Yoon

    2012-11-01

    In this paper, we propose a brand new communication concept, called as "vision communication" based on LED array and image sensor. This system consists of LED array as a transmitter and digital device which include image sensor such as CCD and CMOS as receiver. In order to transmit data, the proposed communication scheme simultaneously uses the digital image processing and optical wireless communication scheme. Therefore, the cognitive communication scheme is possible with the help of recognition techniques used in vision system. By increasing data rate, our scheme can use LED array consisting of several multi-spectral LEDs. Because arranged each LED can emit multi-spectral optical signal such as visible, infrared and ultraviolet light, the increase of data rate is possible similar to WDM and MIMO skills used in traditional optical and wireless communications. In addition, this multi-spectral capability also makes it possible to avoid the optical noises in communication environment. In our vision communication scheme, the data packet is composed of Sync. data and information data. Sync. data is used to detect the transmitter area and calibrate the distorted image snapshots obtained by image sensor. By making the optical rate of LED array be same with the frame rate (frames per second) of image sensor, we can decode the information data included in each image snapshot based on image processing and optical wireless communication techniques. Through experiment based on practical test bed system, we confirm the feasibility of the proposed vision communications based on LED array and image sensor.

  8. Photoacoustic imaging using acoustic reflectors to enhance planar arrays.

    PubMed

    Ellwood, Robert; Zhang, Edward; Beard, Paul; Cox, Ben

    2014-12-01

    Planar sensor arrays have advantages when used for photoacoustic imaging: they do not require the imaging target to be enclosed, and they are easier to manufacture than curved arrays. However, planar arrays have a limited view of the acoustic field due to their finite size; therefore, not all of the acoustic waves emitted from a photoacoustic source can be recorded. This loss of data results in artifacts in the reconstructed photoacoustic image. A detection array configuration which combines a planar Fabry–Pérot sensor with perpendicular acoustic reflectors is described and experimentally implemented. This retains the detection advantages of the planar sensor while increasing the effective detection aperture in order to improve the reconstructed photoacoustic image.

  9. A slot-scanned photodiode-array/CCD hybrid detector for digital mammography.

    PubMed

    Mainprize, James G; Ford, Nancy L; Yin, Shi; Tümer, Türmay; Yaffe, Martin J

    2002-02-01

    We have developed a novel direct conversion detector for use in a slot-scanning digital mammography system. The slot-scan concept allows for dose efficient scatter rejection and the ability to use small detectors to produce a large-area image. The detector is a hybrid design with a 1.0 mm thick silicon PIN photodiode array (the x-ray absorber) indium-bump bonded to a CCD readout that is operated in time-delay integration (TDI) mode. Because the charge capacity requirement for good image quality exceeds the capabilities of standard CCDs, a novel CCD was developed. This CCD consists of 24 independent sections, each acting as a miniature CCD with eight rows for TDI. The signal from each section is combined off-chip to produce a full signal image. The MTF and DQE for the device was measured at several exposures and compared to a linear systems model of signal and noise propagation. Because of the scanning nature of TDI imaging, both the MTF(f) and DQE(f) are reduced along the direction of the scanning motion. For a 26 kVp spectrum, the DQE(0) was measured to be 0.75+/-0.02 for an exposure of 1.29 x 10(-5) C/kg (50 mR).

  10. A Bio-Hybrid Tactile Sensor Incorporating Living Artificial Skin and an Impedance Sensing Array

    PubMed Central

    Cheneler, David; Buselli, Elisa; Camboni, Domenico; Anthony, Carl; Grover, Liam; Adams, Michael John; Oddo, Calogero Maria

    2014-01-01

    The development of a bio-hybrid tactile sensor array that incorporates a skin analogue comprised of alginate encapsulated fibroblasts is described. The electrical properties are modulated by mechanical stress induced during contact, and changes are detected by a ten-channel dual-electrode impedance sensing array. By continuously monitoring the impedance of the sensor array at a fixed frequency, whilst normal and tangential loads are applied to the skin surface, transient mechanotransduction has been observed. The results demonstrate the effectiveness and feasibility of the preliminary prototype bio-hybrid tactile sensor. PMID:25615726

  11. 480 x 8 hybrid HgCdTe infrared focal plane arrays

    NASA Astrophysics Data System (ADS)

    Kobayashi, Masako; Wada, Hideo; Okamura, Toshihiro; Kudo, Jun-ichi; Tanikawa, Kunihiro; Hikida, Soichiro; Miyamoto, Yoshihiro; Miyazaki, Shinji; Yoshida, Yukihiro

    2001-10-01

    This paper explains the technologies used for high-performance long linear arrays based on HgCdTe/CMOS hybrid multiplexers with bidirectional Time Delay and Integration (TDI) functions, and it describes the development of the first high-resolution Forward Looking Infrared (FLIR) system with the SXGA format. Long-wavelength Infrared (LWIR) photodiode arrays are fabricated using liquid-phase epitaxially grown HgCdTe on a CdZnTe substrate. Each photodiode array consists of 480x8-element n+/n-on-p diodes formed by B+ implantation. Each photodiode is surrounded by a crosswise drain diode to define the detection area. The diodes with a 10.3-μm cutoff wavelength had a typical zero-bias resistance of 10 MΩ and a shunt resistance of 1 GΩ. Four CMOS Read Out Integrated Circuits (ROICs) were used for bidirectional TDI and multiplex operations where each ROIC summed up and multiplexed eight signals from 120 channels. The ROIC also includes pixel deselection and gain control circuits along with the corresponding memory and writing means. The Infrared Focal Plane Arrays (IRFPAs) had a typical Noise Equivalent Temperature Difference (NETD) of 18 mK after TDI with F/1.55 optics and 10-μs integration. The FLIR system using the 480x8 IRFPA demonstrated a high spatial resolution of 1280 horizontal lines by 960 vertical lines (SXGA format) and NETD of less than 30 mK. The unique algorithm for image enhancement was successfully confirmed to be efficient.

  12. Comparison of ultrasonic array imaging algorithms for non-destructive evaluation

    NASA Astrophysics Data System (ADS)

    Zhang, J.; Drinkwater, B. W.; Wilcox, P. D.

    2013-01-01

    Ultrasonic array imaging algorithms have been widely used and developed in nondestructive evaluation in the last 10 years. In this paper, three imaging algorithms (Total Focusing Method (TFM), Phase Coherent Imaging (PCI), and Spatial Compounding Imaging (SCI)) are compared through both simulation and experimental measurements. In the simulation, array data sets were generated using a hybrid forward model containing a single defect amongst a multitude of randomly distributed point scatterers to represent backscatter from material microstructure. The Signal to Noise Ratio (SNR) of the final images and their resolution were used to indicate the quality of the different imaging algorithms. The images of different types of defect (point reflectors and planar cracks) were used to investigate the robustness of the imaging algorithms. It is shown that PCI can yield higher image resolution than the TFM, but that the images of cracks are distorted. Overall, the TFM is the most robust algorithm across a range of different types of defects. It is also shown that the detection limit of all three imaging algorithms is almost equal for weakly scattering defects.

  13. Multiple imaging with an aberration optimized hololens array

    NASA Astrophysics Data System (ADS)

    Senthil Kumar, A.; Vasu, R. M.

    1989-08-01

    The imaging performance of hololenses formed with four different geometries were studied through an analysis of their third-order aberration coefficients. It is found that the geometry proposed by Brandt (1969) gives the least residual aberration with minimum variation of this aberration with the reconstruction angle. When the ideal position of one of the construction beams is changed in order to generate a hololens array, the residual aberration is found to increase sharply, which in turn affects the image resolution among the multiplied images in the output. A hololens array was generated using Brandt's geometry with the help of a one-dimensional sinusoidal grating. The results of multiple imaging with the hololens array are presented. The image resolution is reasonably high and can be further improved by reducing the f-number of the hololenses.

  14. Multiple Imaging With An Aberration Optimized Hololens Array

    NASA Astrophysics Data System (ADS)

    Kumar, A. Senthil; Vasu, R. M.

    1989-08-01

    We study the imaging performance of hololenses formed with four different geometries through an analysis of their third-order aberration coefficients. It is found that the geometry proposed by Brandt [Appl. Opt. 8(7), 1421-1429 (1969)] gives the least residual aberration with minimum variation of this aberration with the reconstruction angle. When the ideal position of one of the construction beams is changed in order to generate a hololens array, the residual aberration is found to increase sharply, which in turn affects the image resolution among the multiplied images in the output. We have generated a hololens array using Brandt's geometry with the help of a 1-D sinusoidal grating. The results of multiple imaging with the hololens array are presented. The image resolution is reasonably high and can be further improved by reducing the f-number of the hololenses.

  15. Partial-aperture array imaging in acoustic waveguides

    NASA Astrophysics Data System (ADS)

    Tsogka, Chrysoula; Mitsoudis, Dimitrios A.; Papadimitropoulos, Symeon

    2016-12-01

    We consider the problem of imaging extended reflectors in waveguides using partial-aperture array, i.e. an array that does not span the whole depth of the waveguide. For this imaging, we employ a method that back-propagates a weighted modal projection of the usual array response matrix. The challenge in this setup is to correctly define this projection matrix in order to maintain good energy concentration properties for the imaging method, which were obtained previously by Tsogka et al (2013 SIAM J. Imaging Sci. 6 2714-39) for the full-aperture case. In this paper we propose a way of achieving this and study the properties of the resulting imaging method.

  16. Shielded microstrip array for 7T human MR imaging.

    PubMed

    Wu, Bing; Wang, Chunsheng; Kelley, Douglas A C; Xu, Duan; Vigneron, Daniel B; Nelson, Sarah J; Zhang, Xiaoliang

    2010-01-01

    The high-frequency transceiver array based on the microstrip transmission line design is a promising technique for ultrahigh field magnetic resonance imaging (MRI) signal excitation and reception. However, with the increase of radio-frequency (RF) channels, the size of the ground plane in each microstrip coil element is usually not sufficient to provide a perfect ground. Consequently, the transceiver array may suffer from cable resonance, lower Q-factors, and imaging quality degradations. In this paper, we present an approach to improving the performance of microstrip transceiver arrays by introducing RF shielding outside the microstrip array and the feeding coaxial cables. This improvement reduced interactions among cables, increased resonance stability, and Q-factors, and thus improved imaging quality. An experimental method was also introduced and utilized for quantitative measurement and evaluation of RF coil resonance stability or "cable resonance" behavior.

  17. Range-gated imaging with an indium-gallium-arsenide-based focal plane array

    NASA Astrophysics Data System (ADS)

    Brubaker, Robert M.; Ettenberg, Martin H.; O'Grady, Matthew T.; Blessinger, Michael A.; Dries, J. C.

    2004-08-01

    Range-gated imaging using indium gallium arsenide based focal plane arrays enables both depth and intensity imaging with eye-safe lasers while remaining covert to night vision goggles. We report on a focal plane array consisting of an indium gallium arsenide photodiode array hybrid-integrated with a CMOS readout circuit, resulting in an all solid state device. A 5 V supply avoids the complication of high voltage supplies and improves reliability, while also allowing the device to be small and lightweight. The spectral sensitivity of InGaAs extends from 0.9 microns to 1.7 microns, allowing the use of commercially available pulsed lasers with 1.5 micron wavelength, several millijoule pulse energies, and nanosecond scale pulse durations. SUI is developing a 320 x 256 pixel imager with the ability to conduct range gated imaging with sub-100 ns gates, while also allowing a 16 ms integration time for imaging in a staring mode. The pixels are fabricated on a 25 micron pitch for a compact device, and all pixels are gated simultaneously for "snapshot" exposure. High in-pixel gain with nearly noiseless amplification and low dark current enable high sensitivity imaging from ultra-short gates to video rate imaging.

  18. An extrinsic Si thermal-imaging array

    NASA Astrophysics Data System (ADS)

    Humphreys, R. G.; Webber, R. F.; Holeman, B. R.

    1985-07-01

    A novel coordinate addressed structure for a slow-photoconductor is described which requires only a simple contact pattern to make a large array. The principle has been applied to radiation-damaged doped p-Si, which has a spectral response matching the 3-4.2-micron atmospheric transmission band. 'Staring' thermal imagery with temperature resolution better than 0.1 K has been demonstrated with real-time uniformity correction and display. It is predicted that this level of performance could be achieved in arrays comprising about 10 to the 5th picture points.

  19. Distributed imaging using an array of compressive cameras

    NASA Astrophysics Data System (ADS)

    Ke, Jun; Shankar, Premchandra; Neifeld, Mark A.

    2009-01-01

    We describe a distributed computational imaging system that employs an array of feature specific sensors, also known as compressive imagers, to directly measure the linear projections of an object. Two different schemes for implementing these non-imaging sensors are discussed. We consider the task of object reconstruction and quantify the fidelity of reconstruction using the root mean squared error (RMSE) metric. We also study the lifetime of such a distributed sensor network. The sources of energy consumption in a distributed feature specific imaging (DFSI) system are discussed and compared with those in a distributed conventional imaging (DCI) system. A DFSI system consisting of 20 imagers collecting DCT, Hadamard, or PCA features has a lifetime of 4.8× that of the DCI system when the noise level is 20% and the reconstruction RMSE requirement is 6%. To validate the simulation results we emulate a distributed computational imaging system using an experimental setup consisting of an array of conventional cameras.

  20. Hybrid graphene-copper UWB array sensor for brain tumor detection via scattering parameters in microwave detection system

    NASA Astrophysics Data System (ADS)

    Jamlos, Mohd Aminudin; Ismail, Abdul Hafiizh; Jamlos, Mohd Faizal; Narbudowicz, Adam

    2017-01-01

    Hybrid graphene-copper ultra-wideband array sensor applied to microwave imaging technique is successfully used in detecting and visualizing tumor inside human brain. The sensor made of graphene coated film for the patch while copper for both the transmission line and parasitic element. The hybrid sensor performance is better than fully copper sensor. Hybrid sensor recorded wider bandwidth of 2.0-10.1 GHz compared with fully copper sensor operated from 2.5 to 10.1 GHz. Higher gain of 3.8-8.5 dB is presented by hybrid sensor, while fully copper sensor stated lower gain ranging from 2.6 to 6.7 dB. Both sensors recorded excellent total efficiency averaged at 97 and 94%, respectively. The sensor used for both transmits equivalent signal and receives backscattering signal from stratified human head model in detecting tumor. Difference in the data of the scattering parameters recorded from the head model with presence and absence of tumor is used as the main data to be further processed in confocal microwave imaging algorithm in generating image. MATLAB software is utilized to analyze S-parameter signals obtained from measurement. Tumor presence is indicated by lower S-parameter values compared to higher values recorded by tumor absence.

  1. Multi-Band Large Format Infrared Imaging Arrays

    NASA Technical Reports Server (NTRS)

    Bandara, Sumith V.; Gunapala, Sarath D; Liu, John K.; Hill, Cory J.; Mumolo, Jason M.; Ting, David Z.

    2005-01-01

    Large-format and multi-band focal plane arrays (FPA) based on quantum well and quantum dot infrared photodetectors have been developed for various instruments such as imaging interferometers and hyperspectral imagers. The spectral response of these detectors are tailorable within the mid- and long-wavelength infrared bands.

  2. 3D EFT imaging with planar electrode array: Numerical simulation

    NASA Astrophysics Data System (ADS)

    Tuykin, T.; Korjenevsky, A.

    2010-04-01

    Electric field tomography (EFT) is the new modality of the quasistatic electromagnetic sounding of conductive media recently investigated theoretically and realized experimentally. The demonstrated results pertain to 2D imaging with circular or linear arrays of electrodes (and the linear array provides quite poor quality of imaging). In many applications 3D imaging is essential or can increase value of the investigation significantly. In this report we present the first results of numerical simulation of the EFT imaging system with planar array of electrodes which allows 3D visualization of the subsurface conductivity distribution. The geometry of the system is similar to the geometry of our EIT breast imaging system providing 3D conductivity imaging in form of cross-sections set with different depth from the surface. The EFT principle of operation and reconstruction approach differs from the EIT system significantly. So the results of numerical simulation are important to estimate if comparable quality of imaging is possible with the new contactless method. The EFT forward problem is solved using finite difference time domain (FDTD) method for the 8×8 square electrodes array. The calculated results of measurements are used then to reconstruct conductivity distributions by the filtered backprojections along electric field lines. The reconstructed images of the simple test objects are presented.

  3. Innovative LuYAP:Ce array for PET imaging

    NASA Astrophysics Data System (ADS)

    Cinti, M. N.; Scafe, R.; Bennati, P.; Lo Meo, S.; Frantellizzi, V.; Pellegrini, R.; De Vincentis, G.; Sacco, D.; Fabbri, A.; Pani, R.

    2017-03-01

    We present an imaging characterization of a 10 × 10 LuYAP array (2 × 2 × 10 mm3 pixels) with an innovative dielectric coating insulation (0.015 mm thick), in view of its possible use in a gamma camera for imaging positron emission tomography (PET) or in similar applications, e.g. as γ -prompt detector in hadron therapy. The particular assembly of this array was realized in order to obtain a packing fraction of 98%, improving detection efficiency and light collection. For imaging purpose, the array has been coupled with a selected Hamamatsu H10966-100 Multi Anode Photomultiplier read out by a customized 64 independent channels electronics. This tube presents a superbialkali photocathode with 38% of quantum efficiency, permitting to enhance energy resolution and consequently image quality. A pixel identification of about 0.5 mm at 662 keV was obtained, highlighting the potentiality of this detector in PET applications.

  4. Guided wave phased array beamforming and imaging in composite plates.

    PubMed

    Yu, Lingyu; Tian, Zhenhua

    2016-05-01

    This paper describes phased array beamforming using guided waves in anisotropic composite plates. A generic phased array algorithm is presented, in which direction dependent guided wave parameters and the energy skew effect are considered. This beamforming at an angular direction is achieved based on the classic delay-and-sum principle by applying phase delays to signals received at array elements and adding up the delayed signals. The phase delays are determined with the goal to maximize the array output at the desired direction and minimize it otherwise. For array characterization, the beam pattern of rectangular grid arrays in composite plates is derived. In addition to the beam pattern, the beamforming factor in terms of wavenumber distribution is defined to provide intrinsic explanations for phased array beamforming. The beamforming and damage detection in a composite plate are demonstrated using rectangular grid arrays made by a non-contact scanning laser Doppler vibrometer. Detection images of the composite plate with multiple surface defects at various directions are obtained. The results show that the guided wave phased array method is a potential effective method for rapid inspection of large composite structures.

  5. Ultrasonic array imaging in nondestructive evaluation: total focusing method with using circular coherence factor

    NASA Astrophysics Data System (ADS)

    Zhang, Jie; Drinkwater, Bruce W.; Wilcox, Paul D.

    2013-01-01

    Ultrasonic array imaging algorithms have been widely used and developed in non-destructive evaluation in the last 10 years. In this paper, a widely-used imaging algorithms, Total Focusing Method (TFM), was further developed with using the phase statistical information of the scattering field from a scatterer, i.e., Circular Coherence Factor (CCF). TFM and TFM with using CCF are compared through both simulation and experimental measurements. In the simulation, array data sets were generated by using a hybrid forward model containing a single defect amongst a multitude of randomly distributed point scatterers to represent backscatter from material microstructure. The number of point scatterers per unit area and their scattering amplitude were optimized to reduce computation cost. The Signal to Noise Ratio (SNR) of the finial images and their resolution were used to indicate the quality of the different imaging algorithms. The images of different types of defect (point reflectors and planar cracks) were used to investigate the robustness of the imaging algorithms. It is shown that, with using CCF, higher image resolution can be achieved, but that the images of cracks are distorted. It is also shown that the detection limit of the imaging algorithms is almost equal for weakly scattering defects.

  6. Real-time aerial multispectral imaging solutions using dichroic filter arrays

    NASA Astrophysics Data System (ADS)

    Chandler, Eric V.; Fish, David E.

    2014-06-01

    The next generation of multispectral sensors and cameras needs to deliver significant improvements in size, weight, portability, and spectral band customization to support widespread commercial deployment for a variety of purposebuilt aerial, unmanned, and scientific applications. The benefits of multispectral imaging are well established for applications including machine vision, biomedical, authentication, and remote sensing environments - but many aerial and OEM solutions require more compact, robust, and cost-effective production cameras to realize these benefits. A novel implementation uses micropatterning of dichroic filters into Bayer and custom mosaics, enabling true real-time multispectral imaging with simultaneous multi-band image acquisition. Consistent with color camera image processing, individual spectral channels are de-mosaiced with each channel providing an image of the field of view. We demonstrate recent results of 4-9 band dichroic filter arrays in multispectral cameras using a variety of sensors including linear, area, silicon, and InGaAs. Specific implementations range from hybrid RGB + NIR sensors to custom sensors with applicationspecific VIS, NIR, and SWIR spectral bands. Benefits and tradeoffs of multispectral sensors using dichroic filter arrays are compared with alternative approaches - including their passivity, spectral range, customization options, and development path. Finally, we report on the wafer-level fabrication of dichroic filter arrays on imaging sensors for scalable production of multispectral sensors and cameras.

  7. Real-time compact multispectral imaging solutions using dichroic filter arrays

    NASA Astrophysics Data System (ADS)

    Chandler, Eric V.; Fish, David E.

    2014-03-01

    The next generation of multispectral sensors and cameras will need to deliver significant improvements in size, weight, portability, and spectral band customization to support widespread commercial deployment. The benefits of multispectral imaging are well established for applications including machine vision, biomedical, authentication, and aerial remote sensing environments - but many OEM solutions require more compact, robust, and cost-effective production cameras to realize these benefits. A novel implementation uses micro-patterning of dichroic filters into Bayer and custom mosaics, enabling true real-time multispectral imaging with simultaneous multi-band image acquisition. Consistent with color camera image processing, individual spectral channels are de-mosaiced with each channel providing an image of the field of view. We demonstrate recent results of 4-9 band dichroic filter arrays in multispectral cameras using a variety of sensors including linear, area, silicon, and InGaAs. Specific implementations range from hybrid RGB + NIR sensors to custom sensors with application-specific VIS, NIR, and SWIR spectral bands. Benefits and tradeoffs of multispectral sensors using dichroic filter arrays are compared with alternative approaches - including their passivity, spectral range, customization options, and development path. Finally, we report on the wafer-level fabrication of dichroic filter arrays on imaging sensors for scalable production of multispectral sensors and cameras.

  8. Enabling Large Focal Plane Arrays Through Mosaic Hybridization

    NASA Technical Reports Server (NTRS)

    Miller, Timothy M.; Jhabvala, Christine A.; Leong, Edward; Costen, Nicholas P.; Sharp, Elmer; Adachi, Tomoko; Benford, Dominic J.

    2012-01-01

    We have demonstrated advances in mosaic hybridization that will enable very large format far-infrared detectors. Specifically we have produced electrical detector models via mosaic hybridization yielding superconducting circuit paths by hybridizing separately fabricated sub-units onto a single detector unit. The detector model was made on a 100mm diameter wafer while four model readout quadrant chips were made from a separate 100mm wafer. The individually fabricated parts were hybridized using a flip-chip bonder to assemble the detector-readout stack. Once all of the hybridized readouts were in place, a single, large and thick silicon substrate was placed on the stack and attached with permanent epoxy to provide strength and a Coefficient of Thermal Expansion match to the silicon components underneath. Wirebond pads on the readout chips connect circuits to warm readout electronics; and were used to validate the successful superconducting electrical interconnection of the model mosaic-hybrid detector. This demonstration is directly scalable to 150 mm diameter wafers, enabling pixel areas over ten times the area currently available.

  9. Enabling Large Focal Plane Arrays Through Mosaic Hybridization

    NASA Technical Reports Server (NTRS)

    Miller, Timothy M.; Jhabvala, Christine A.; Leong, Edward; Costen, Nick P.; Sharp, Elmer; Adachi, Tomoko; Benford, Dominic J.

    2012-01-01

    We have demonstrated advances in mosaic hybridization that will enable very large format far-infrared detectors. Specifically we have produced electrical detector models via mosaic hybridization yielding superconducting circuit patbs by hybridizing separately fabricated sub-units onto a single detector unit. The detector model was made on a 100mm diameter wafer while four model readout quadrant chips were made from a separate 100mm wafer. The individually fabric.ted parts were hybridized using a Suss FCI50 flip chip bonder to assemble the detector-readout stack. Once all of the hybridized readouts were in place, a single, large and thick silicon substrate was placed on the stack and attached with permanent epoxy to provide strength and a Coefficient of Thermal Expansion match to the silicon components underneath. Wirebond pads on the readout chips connect circuits to warm readout electronics; and were used to validate the successful superconducting electrical interconnection of the model mosaic-hybrid detector. This demonstration is directly scalable to 150 mm diameter wafers, enabling pixel areas over ten times the area currently available.

  10. PIT-like effect with high directivity in hybrid plasmonic array

    NASA Astrophysics Data System (ADS)

    Ni, Yuan; Zhang, Cheng; Wang, Yong; Lu, Yonghua; Wang, Pei; Zhang, Douguo; Ming, Hai

    2016-12-01

    We demonstrate the existence of plasmon-induced transparency (PIT) like spectral response in a hybrid system of plasmonic antenna array coupled with dielectric silicon array. After tuning the period of the silicon array, different resonant wavelength with high quality factor (range from 50 to 400) can be achieved. When the subradiant resonator (dielectric array) get close to the superradiant resonator (metallic nanoantenna array), a peak of PIT comes into emerging between the two asymmetric resonant dips. Meanwhile, the far-field emission pattern of the PIT peak was also observed with a highly directivity that was neatly two times than a same period of plasmonic Au array and the backward scattering was obviously suppressed. Our works provide productive insight into the light manipulation with near-field electromagnetic coupling.

  11. Piezoelectric annular array for large depth of field photoacoustic imaging

    PubMed Central

    Passler, K.; Nuster, R.; Gratt, S.; Burgholzer, P.; Paltauf, G.

    2011-01-01

    A piezoelectric detection system consisting of an annular array is investigated for large depth of field photoacoustic imaging. In comparison to a single ring detection system, X-shaped imaging artifacts are suppressed. Sensitivity and image resolution studies are performed in simulations and in experiments and compared to a simulated spherical detector. In experiment an eight ring detection systems offers an extended depth of field over a range of 16 mm with almost constant lateral resolution. PMID:21991555

  12. Hybrid Image-Plane/Stereo Manipulation

    NASA Technical Reports Server (NTRS)

    Baumgartner, Eric; Robinson, Matthew

    2004-01-01

    Hybrid Image-Plane/Stereo (HIPS) manipulation is a method of processing image data, and of controlling a robotic manipulator arm in response to the data, that enables the manipulator arm to place an end-effector (an instrument or tool) precisely with respect to a target (see figure). Unlike other stereoscopic machine-vision-based methods of controlling robots, this method is robust in the face of calibration errors and changes in calibration during operation. In this method, a stereoscopic pair of cameras on the robot first acquires images of the manipulator at a set of predefined poses. The image data are processed to obtain image-plane coordinates of known visible features of the end-effector. Next, there is computed an initial calibration in the form of a mapping between (1) the image-plane coordinates and (2) the nominal three-dimensional coordinates of the noted end-effector features in a reference frame fixed to the main robot body at the base of the manipulator. The nominal three-dimensional coordinates are obtained by use of the nominal forward kinematics of the manipulator arm that is, calculated by use of the currently measured manipulator joint angles and previously measured lengths of manipulator arm segments under the assumption that the arm segments are rigid, that the arm lengths are constant, and that there is no backlash. It is understood from the outset that these nominal three-dimensional coordinates are likely to contain possibly significant calibration errors, but the effects of the errors are progressively reduced, as described next. As the end-effector is moved toward the target, the calibration is updated repeatedly by use of data from newly acquired images of the end-effector and of the corresponding nominal coordinates in the manipulator reference frame. By use of the updated calibration, the coordinates of the target are computed in manipulator-reference-frame coordinates and then used to the necessary manipulator joint angles to position

  13. A hybrid continuous-wave terahertz imaging system

    SciTech Connect

    Dolganova, Irina N. Zaytsev, Kirill I. Metelkina, Anna A.; Karasik, Valeriy E.; Yurchenko, Stanislav O.

    2015-11-15

    A hybrid (active-passive mode) terahertz (THz) imaging system and an algorithm for imaging synthesis are proposed to enhance the THz image quality. The concept of image contrast is used to compare active and passive THz imaging. Combining the measurement of the self-emitted radiation of the object with the back-scattered source radiation measurement, it becomes possible to use the THz image to retrieve maximum information about the object. The experimental results confirm the advantages of hybrid THz imaging systems, which can be generalized for a wide range of applications in the material sciences, chemical physics, bio-systems, etc.

  14. Coded aperture imaging with self-supporting uniformly redundant arrays

    DOEpatents

    Fenimore, Edward E.

    1983-01-01

    A self-supporting uniformly redundant array pattern for coded aperture imaging. The present invention utilizes holes which are an integer times smaller in each direction than holes in conventional URA patterns. A balance correlation function is generated where holes are represented by 1's, nonholes are represented by -1's, and supporting area is represented by 0's. The self-supporting array can be used for low energy applications where substrates would greatly reduce throughput. The balance correlation response function for the self-supporting array pattern provides an accurate representation of the source of nonfocusable radiation.

  15. A handy motion driven hybrid energy harvester: dual Halbach array based electromagnetic and triboelectric generators

    NASA Astrophysics Data System (ADS)

    Salauddin, M.; Park, J. Y.

    2016-11-01

    In this work, we have proposed and experimentally validated of hybrid electromagnetic and triboelectric energy harvester using dual Halbach magnets array excited by human handy motion. Hybrid electromagnetic (EM) and triboelectric (TE) generator that can deliver an output performance much higher than that of the individual energy-harvesting unit due to the combination operation of EM and TE mechanisms under the same mechanical movements. A Halbach array concentrates the magnetic flux lines on one side of the array while suppressing the flux lines on the other side. Dual Halbach array allows the concentrated magnetic flux lines to interact with the same coil in a way where maximum flux linkage occurs. When an external mechanical vibration is applied to the hybrid structure in the axial direction of the harvester, the suspended mass (two sided dual-Halbach-array frame) starts to oscillate within the magnetic springs and TEG part. Therefore, the TEG part, the Al film and microstructure PDMS film are collected into full contact with each other, generating triboelectric charges due to the various triboelectricities between them. A prototype of the hybrid harvester has been fabricated and tested. The EMG is capable of delivering maximum 11.5mW peak power at 32.5Ω matching load resistance and the TEG delivering 88μW peak power at 10MΩ load resistance.

  16. AFRL Nanotechnology Initiative: Hybrid Nanomaterials in Photonic Crystal Cavities for Multi-Spectral Infrared Detector Arrays

    DTIC Science & Technology

    2010-03-31

    INITIATIVE) HYBRID NANOMATERIALS IN PHOTONIC CRYSTAL CAVITIES FOR MULTI -SPECTRAL INFRARED DETECTOR ARRAYS 5b. GRANT NUMBER F A9550-06-1-0482 5c...IR) photodetector using hybrid nanornaterials in photonic crystal (PC) cavities for enhanced absorption at selected wavelengths. The simultaneous...infrared photodetection, quantum dots, photonic crystal cavities, matrix-assisted pulsed laser evaporation 16. SECURITY CLASSIFICATION OF: 17. LIMITATION OF

  17. Pyroelectric sensor arrays for detection and thermal imaging

    NASA Astrophysics Data System (ADS)

    Holden, Anthony J.

    2013-06-01

    Penetration of uncooled (room temperature operation) thermal detector arrays into high volume commercial products depends on very low cost technology linked to high volume production. A series of innovative and revolutionary developments is now allowing arrays based on bulk pyroelectric ceramic material to enter the consumer marketplace providing everything from sophisticated security and people monitoring devices to hand held thermal imagers and visual IR thermometers for preventative maintenance and building inspection. Although uncooled resistive microbolometer detector technology has captured market share in higher cost thermal imager products we describe a pyroelectric ceramic technology which does not need micro electro-mechanical systems (MEMS) technology and vacuum packaging to give good performance. This is a breakthrough for very low cost sensors and imagers. Recent developments in a variety of products based on pyroelectric ceramic arrays are described and their performance and applicability compared and contrasted with competing technologies.

  18. Pupil geometry and pupil re-imaging in telescope arrays

    NASA Technical Reports Server (NTRS)

    Traub, Wesley A.

    1990-01-01

    This paper considers the issues of lateral and longitudinal pupil geometry in ground-based telescope arrays, such as IOTA. In particular, it is considered whether or not pupil re-imaging is required before beam combination. By considering the paths of rays through the system, an expression is derived for the optical path errors in the combined wavefront as a function of array dimensions, telescope magnification factor, viewing angle, and field-of-view. By examining this expression for the two cases of pupil-plane and image-plane combination, operational limits can be found for any array. As a particular example, it is shown that for IOTA no pupil re-imaging optics will be needed.

  19. Thin polymer etalon arrays for high-resolution photoacoustic imaging

    PubMed Central

    Hou, Yang; Huang, Sheng-Wen; Ashkenazi, Shai; Witte, Russell; O’Donnell, Matthew

    2009-01-01

    Thin polymer etalons are demonstrated as high-frequency ultrasound sensors for three-dimensional (3-D) high-resolution photoacoustic imaging. The etalon, a Fabry-Perot optical resonator, consists of a thin polymer slab sandwiched between two gold layers. It is probed with a scanning continuous-wave (CW) laser for ultrasound array detection. Detection bandwidth of a 20-μm-diam array element exceeds 50 MHz, and the ultrasound sensitivity is comparable to polyvinylidene fluoride (PVDF) equivalents of similar size. In a typical photoacoustic imaging setup, a pulsed laser beam illuminates the imaging target, where optical energy is absorbed and acoustic waves are generated through the thermoelastic effect. An ultrasound detection array is formed by scanning the probing laser beam on the etalon surface in either a 1-D or a 2-D configuration, which produces 2-D or 3-D images, respectively. Axial and lateral resolutions have been demonstrated to be better than 20 μm. Detailed characterizations of the optical and acoustical properties of the etalon, as well as photoacoustic imaging results, suggest that thin polymer etalon arrays can be used as ultrasound detectors for 3-D high-resolution photoacoustic imaging applications. PMID:19123679

  20. Photoluminescence spectroscopy and lifetime measurements from self assembled semiconducting quantum dot- metal nanoparticle hybrid arrays

    NASA Astrophysics Data System (ADS)

    Haridas, M.; Basu, J. K.

    2011-03-01

    We demonstrate how the emission properties of a hybrid array consisting of semiconducting quantum dot (QD) and metal nanoparticles (NP) can be controlled by varying the density and distance between QD and NP independently. Our hybrid system consists of chemically synthesized cadmium selenide quantum dots (CdSe QDs) and polymer capped gold nanoparticles (Au NP) embedded in a block copolymer matrix having the topology of cylinders oriented perpendicular to the substrate. We have prepared hybrid arrays with two different densities of CdSe QDs (ρQD) each having same Au NP densities (ρAu) . The photoluminescence measurements (PL) from such hybrid system shows enhancement in emission with increase in ρAu , compared to the CdSe QD film and the enhancement factor is lower for hybrid films with high ρQD . The lifetime measurement shows double exponent PL decay with systematic reduction in exciton lifetime for hybrid arrays with respect to ρAu . The film with high ρQD shows larger reduction in lifetime. Similarly, the amplitudes of the two relaxations switch over with increase in ρAu . It is clear that the shorter time becomes the dominant relaxation mode with increasing ρAu . Observed phenomena have been explained in terms of exciton plasmon interaction .

  1. Imaging and data processing with the Low Frequency Space Array

    NASA Technical Reports Server (NTRS)

    Simon, R. S.; Spencer, J. H.; Dennison, B. K.; Weiler, K. W.; Johnston, K. J.; Kaiser, M. L.; Desch, M. D.; Fainberg, J.; Brown, L. W.; Stone, R. G.

    1987-01-01

    The Low Frequency Space Array (LFSA) is being designed to image the entire sky at extremely low radio frequencies with arcmin to subarcmin resolution. To accomplish this goal, data from LFSA will be continuously integrated for many months and then be used with aperture synthesis techniques to produce images. The three dimensional nature of LFSA and the effects of orbital geometry make LFSA a continuously evolving array which has an excellent synthesized point-response function. After transforming the data to produce an initial image, it is possible to remove low-level sidelobe responses remaining in the image and thereby produce a high dynamic-range image. Interference (both man-made and from solar-system objects) is a potential problem for LFSA, but appropriate data handling techniques are available which should eliminate any of its effects.

  2. Photodetector Arrays for Multicolor Visible/Infrared Imaging

    NASA Technical Reports Server (NTRS)

    Gunapala, Sarath; Bandara, Sumith; Liu, John; Ting, David

    2006-01-01

    Monolithic focal-plane arrays of photodetectors capable of imaging the same scenes simultaneously in multiple wavelength bands in the visible and infrared spectral regions have been proposed. In prior visible/infrared imaging systems, it has been standard practice to use separate optical trains to form images in visible and infrared wavelength bands on separate visibleand infrared-photodetector arrays. Because the proposal would enable the detection of images in multiple wavelength bands on the same focal plane, the proposal would make it unnecessary to use multiple optical trains. Hence, multispectral imaging systems could be made more compact and the difficulties of aligning multiple optical trains would be eliminated. Each pixel in an array according to the proposal would contain stacks of several photodetectors. The proposal is a logical extension of prior concepts of arrays of stacked photodetectors for imaging in two or three wavelength bands. For example, such an array was described in Three-Color Focal-Plane Array of Infrared QWIPs (NPO-20683), NASA Tech Briefs, Vol. 24, No. 5 (May 2000), page 26a. In one proposed design, (see figure), each pixel would be divided into four subpixels, one being dedicated to a visible- and-near-infrared (V) band, one to a combination of the V band and a verylong- wavelength infrared (VLWIR) band, one to a combination of the V band and a long-wavelength infrared (LWIR) band, and one to a combination of the V band and a medium-wavelength infrared (MWIR) band. For this purpose, each subpixel would include a GaAs-based positive/intrinsic/negative (PIN) photodiode for detection in the V band stacked with three quantum-well infrared photodetectors (QWIPs), each optimized for one of the aforementioned infrared bands. The stacks of photodetectors in all the subpixels would be identical except for the electrical connections, which would be configured to activate the various wavelengthband combinations.

  3. A Multimodality Hybrid Gamma-Optical Camera for Intraoperative Imaging

    PubMed Central

    Lees, John E.; Bugby, Sarah L.; Alqahtani, Mohammed S.; Jambi, Layal K.; Dawood, Numan S.; McKnight, William R.; Ng, Aik H.; Perkins, Alan C.

    2017-01-01

    The development of low profile gamma-ray detectors has encouraged the production of small field of view (SFOV) hand-held imaging devices for use at the patient bedside and in operating theatres. Early development of these SFOV cameras was focussed on a single modality—gamma ray imaging. Recently, a hybrid system—gamma plus optical imaging—has been developed. This combination of optical and gamma cameras enables high spatial resolution multi-modal imaging, giving a superimposed scintigraphic and optical image. Hybrid imaging offers new possibilities for assisting clinicians and surgeons in localising the site of uptake in procedures such as sentinel node detection. The hybrid camera concept can be extended to a multimodal detector design which can offer stereoscopic images, depth estimation of gamma-emitting sources, and simultaneous gamma and fluorescence imaging. Recent improvements to the hybrid camera have been used to produce dual-modality images in both laboratory simulations and in the clinic. Hybrid imaging of a patient who underwent thyroid scintigraphy is reported. In addition, we present data which shows that the hybrid camera concept can be extended to estimate the position and depth of radionuclide distribution within an object and also report the first combined gamma and Near-Infrared (NIR) fluorescence images. PMID:28282957

  4. Investigation on 2.45-THz array transmission imaging

    NASA Astrophysics Data System (ADS)

    Yao, Rui; Li, Qi; Ding, Shenghui; Wang, Qi

    2009-07-01

    THz transmission imaging is considered as a promising detection measure and imaging method with wide application prospect in security inspection and counter-terrorism. And high-speed array imaging is a very important direction. In this paper, 2.45-THz transmission imaging experiments are made by applying a 124×124 array detector. The 2.45-THz CW CO2-pumped laser is used as illumination source and its output power is about 17mW. Some undersize articles (gasket, screw and nut) are chosen as objects. THz imaging experiments are respectively demonstrated through 1-2 pieces of paper and two kinds of envelopes to show the imaging effect. The original data is acquired and some image processing methods (5-frame average, median filtering, etc) are used to improve the image effect. Finally the THz images obtained are basically clear. The experimental results show that utilizing the setup designed for 2.45-THz imaging, the images are fast generated and objects' contours are clear through paper and envelop.

  5. Conceptual design of a hybrid Ge:Ga detector array

    NASA Technical Reports Server (NTRS)

    Parry, C. M.

    1984-01-01

    For potential applications in space infrared astronomy missions such as the Space Infrared Telescope Facility and the Large Deployable Reflector, integrated arrays of long-wavelength detectors are desired. The results of a feasibility study which developed a design for applying integrated array techniques to a long-wavelength (gallium-doped germanium) material to achieve spectral coverage between 30 and 200 microns are presented. An approach which builds up a two-dimensional array by stacking linear detector modules is presented. The spectral response of the Ge:Ga detectors is extended to 200 microns by application of uniaxial stress to the stack of modules. The detectors are assembled with 1 mm spacing between the elements. Multiplexed readout of each module is accomplished with integration sampling of a metal-oxide-semiconductor (MOS) switch chip. Aspects of the overall design, including the anticipated level of particle effects on the array in the space environment, a transparent electrode design for 200 microns response, estimates of optical crosstalk, and mechanical stress design calculations are included.

  6. Indium Hybridization of Large Format TES Bolometer Arrays to Readout Multiplexers for Far-Infrared Astronomy

    NASA Technical Reports Server (NTRS)

    Miller, Timothy M.; Costen, Nick; Allen, Christine

    2007-01-01

    The advance of new detector technologies combined with enhanced fabrication methods has resulted in an increase in development of large format arrays. The next generation of scientific instruments will utilize detectors containing hundreds to thousands of elements providing a more efficient means to conduct large area sky surveys. Some notable detectors include a 32x32 x-ray microcalorimeter for Constellation-X, an infrared bolometer called SAFIRE to fly on the airborne observatory SOFIA, and the sub-millimeter bolometer SCUBA-2 to be deployed at the JCMT which will use more than 10,000 elements for two colors, each color using four 32x40 arrays. Of these detectors, SCUBA-2 is farthest along in development and uses indium hybridization to multiplexers for readout of the large number of elements, a technology that will be required to enable the next generation of large format arrays. Our current efforts in working toward large format arrays have produced GISMO, the Goddard IRAM Superconducting 2-Millimeter observer. GISMO is a far infrared instrument to be field tested later this year at the IRAM 30 meter telescope in Spain. GISMO utilizes transition edge sensor (TES) technology in an 8x16 filled array format that allows for typical fan-out wiring and wire-bonding to four 1x32 NIST multiplexers. GISMO'S electrical wiring is routed along the tops of 30 micron walls which also serve as the mechanical framework for the array. This architecture works well for the 128 element array, but is approaching the limit for routing the necessary wires along the surface while maintaining a high fill factor. Larger format arrays will benefit greatly from making electrical connections through the wafer to the backside, where they can be hybridized to a read-out substrate tailored to handling the wiring scheme. The next generation array we are developing is a 32x40 element array on a pitch of 1135 microns that conforms to the NIST multiplexer, already developed for the SCUBA-2

  7. High-frequency ultrasonic arrays for ocular imaging

    NASA Astrophysics Data System (ADS)

    Jaeger, M. D.; Kline-Schoder, R. J.; Douville, G. M.; Gagne, J. R.; Morrison, K. T.; Audette, W. E.; Kynor, D. B.

    2007-03-01

    High-resolution ultrasound imaging of the anterior portion of the eye has been shown to provide important information for sizing of intraocular lens implants, diagnosis of pathological conditions, and creation of detailed maps of corneal topography to guide refractive surgery. Current ultrasound imaging systems rely on mechanical scanning of a single acoustic element over the surface of the eye to create the three-dimensional information needed by clinicians. This mechanical scanning process is time-consuming and subject to errors caused by eye movement during the scanning period. This paper describes development of linear ultrasound imaging arrays intended to increase the speed of image acquisition and reduce problems associated with ocular motion. The arrays consist of a linear arrangement of high-frequency transducer elements designed to operate in the 50 - 75 MHz frequency range. The arrays are produced using single-crystal lithium niobate piezoelectric material, thin film electrodes, and epoxy-based acoustic layers. The array elements have been used to image steel test structures and bovine cornea.

  8. Submillimeter video imaging with a superconducting bolometer array

    NASA Astrophysics Data System (ADS)

    Becker, Daniel Thomas

    Millimeter wavelength radiation holds promise for detection of security threats at a distance, including suicide bombers and maritime threats in poor weather. The high sensitivity of superconducting Transition Edge Sensor (TES) bolometers makes them ideal for passive imaging of thermal signals at millimeter and submillimeter wavelengths. I have built a 350 GHz video-rate imaging system using an array of feedhorn-coupled TES bolometers. The system operates at standoff distances of 16 m to 28 m with a measured spatial resolution of 1.4 cm (at 17 m). It currently contains one 251-detector sub-array, and can be expanded to contain four sub-arrays for a total of 1004 detectors. The system has been used to take video images that reveal the presence of weapons concealed beneath a shirt in an indoor setting. This dissertation describes the design, implementation and characterization of this system. It presents an overview of the challenges associated with standoff passive imaging and how these problems can be overcome through the use of large-format TES bolometer arrays. I describe the design of the system and cover the results of detector and optical characterization. I explain the procedure used to generate video images using the system, and present a noise analysis of those images. This analysis indicates that the Noise Equivalent Temperature Difference (NETD) of the video images is currently limited by artifacts of the scanning process. More sophisticated image processing algorithms can eliminate these artifacts and reduce the NETD to 100 mK, which is the target value for the most demanding passive imaging scenarios. I finish with an overview of future directions for this system.

  9. Robust detection of defects in imaging arrays

    NASA Astrophysics Data System (ADS)

    Dudas, Jozsef; Jung, Cory; Chapman, Glenn H.; Koren, Zahava; Koren, Israel

    2006-01-01

    As digital imagers continue to increase in size and pixel density, the detection of faults in the field becomes critical to delivering high quality output. Traditional schemes for defect detection utilize specialized hardware at the time of manufacture and are impractical for use in the field, while previously proposed software-based approaches tend to lead to quality-degrading false positive diagnoses. This paper presents an algorithm that utilizes statistical information extracted from a sequence of normally captured images to identify the location and type of defective pixels. Building on previous research, this algorithm utilizes data local to each pixel and Bayesian statistics to more accurately infer the likelihood of each defect, which successfully improves the detection time. Several defect types are considered, including pixels with one-half of the typical sensitivity and permanently stuck pixels. Monte Carlo simulations have shown that for defect densities of up to 0.5%, 50 ordinary images are sufficient to accurately identify all faults without falsely diagnosing good pixels as faulty. Testing also indicates that the algorithm can be extended to higher resolution imagers and to those with noisy stuck pixels, with only minimal cost to performance.

  10. Code-modulated interferometric imaging system using phased arrays

    NASA Astrophysics Data System (ADS)

    Chauhan, Vikas; Greene, Kevin; Floyd, Brian

    2016-05-01

    Millimeter-wave (mm-wave) imaging provides compelling capabilities for security screening, navigation, and bio- medical applications. Traditional scanned or focal-plane mm-wave imagers are bulky and costly. In contrast, phased-array hardware developed for mass-market wireless communications and automotive radar promise to be extremely low cost. In this work, we present techniques which can allow low-cost phased-array receivers to be reconfigured or re-purposed as interferometric imagers, removing the need for custom hardware and thereby reducing cost. Since traditional phased arrays power combine incoming signals prior to digitization, orthogonal code-modulation is applied to each incoming signal using phase shifters within each front-end and two-bit codes. These code-modulated signals can then be combined and processed coherently through a shared hardware path. Once digitized, visibility functions can be recovered through squaring and code-demultiplexing operations. Pro- vided that codes are selected such that the product of two orthogonal codes is a third unique and orthogonal code, it is possible to demultiplex complex visibility functions directly. As such, the proposed system modulates incoming signals but demodulates desired correlations. In this work, we present the operation of the system, a validation of its operation using behavioral models of a traditional phased array, and a benchmarking of the code-modulated interferometer against traditional interferometer and focal-plane arrays.

  11. 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.

  12. Strain Mapping in Metals Using Ultrasonic Array Speckle Images

    NASA Astrophysics Data System (ADS)

    Bowler, A. I.; Drinkwater, B. W.; Wilcox, P. D.

    2009-03-01

    The full-field non-destructive measurement of internal displacement and strain fields is of interest in many engineering applications. This paper describes an approach to measuring internal displacements and strains in metals which uses the correlation of ultrasonic speckle images of the internal structure of the material. This has the key advantage over optical surface displacement and strain measurement techniques in that internal information can be obtained. Experiments are described which use a 1-D ultrasonic array to map 2-D displacement fields for uniform translation and uniaxial tension of a metallic bar. The full matrix of transmit-receive signals from the array was post-processed to generate speckle images using a Fourier-domain imaging algorithm. Block-search cross-correlation was used to find the displacements of small sub-images corresponding to regions within the bar. Potential applications include characterising crack networks and creep damage detection.

  13. Design, processing and testing of LSI arrays: Hybrid microelectronics task

    NASA Technical Reports Server (NTRS)

    Himmel, R. P.; Stuhlbarg, S. M.; Ravetti, R. G.; Zulueta, P. J.

    1979-01-01

    Mathematical cost factors were generated for both hybrid microcircuit and printed wiring board packaging methods. A mathematical cost model was created for analysis of microcircuit fabrication costs. The costing factors were refined and reduced to formulae for computerization. Efficient methods were investigated for low cost packaging of LSI devices as a function of density and reliability. Technical problem areas such as wafer bumping, inner/outer leading bonding, testing on tape, and tape processing, were investigated.

  14. Density-tapered spiral arrays for ultrasound 3-D imaging.

    PubMed

    Ramalli, Alessandro; Boni, Enrico; Savoia, Alessandro Stuart; Tortoli, Piero

    2015-08-01

    The current high interest in 3-D ultrasound imaging is pushing the development of 2-D probes with a challenging number of active elements. The most popular approach to limit this number is the sparse array technique, which designs the array layout by means of complex optimization algorithms. These algorithms are typically constrained by a few steering conditions, and, as such, cannot guarantee uniform side-lobe performance at all angles. The performance may be improved by the ungridded extensions of the sparse array technique, but this result is achieved at the expense of a further complication of the optimization process. In this paper, a method to design the layout of large circular arrays with a limited number of elements according to Fermat's spiral seeds and spatial density modulation is proposed and shown to be suitable for application to 3-D ultrasound imaging. This deterministic, aperiodic, and balanced positioning procedure attempts to guarantee uniform performance over a wide range of steering angles. The capabilities of the method are demonstrated by simulating and comparing the performance of spiral and dense arrays. A good trade-off for small vessel imaging is found, e.g., in the 60λ spiral array with 1.0λ elements and Blackman density tapering window. Here, the grating lobe level is -16 dB, the lateral resolution is lower than 6λ the depth of field is 120λ and, the average contrast is 10.3 dB, while the sensitivity remains in a 5 dB range for a wide selection of steering angles. The simulation results may represent a reference guide to the design of spiral sparse array probes for different application fields.

  15. Real-time detection of DNA hybridization and melting on oligonucleotide arrays by using optical wave guides.

    PubMed Central

    Stimpson, D I; Hoijer, J V; Hsieh, W T; Jou, C; Gordon, J; Theriault, T; Gamble, R; Baldeschwieler, J D

    1995-01-01

    The challenge of the Human Genome Project is to increase the rate of DNA sequence acquisition by two orders of magnitude to complete sequencing of the human genome by the year 2000. The present work describes a rapid detection method using a two-dimensional optical wave guide that allows measurement of real-time binding or melting of a light-scattering label on a DNA array. A particulate label on the target DNA acts as a light-scattering source when illuminated by the evanescent wave of the wave guide and only the label bound to the surface generates a signal. Imaging/visual examination of the scattered light permits interrogation of the entire array simultaneously. Hybridization specificity is equivalent to that obtained with a conventional system using autoradiography. Wave guide melting curves are consistent with those obtained in the liquid phase and single-base discrimination is facile. Dilution experiments showed an apparent lower limit of detection at 0.4 nM oligonucleotide. This performance is comparable to the best currently known fluorescence-based systems. In addition, wave guide detection allows manipulation of hybridization stringency during detection and thereby reduces DNA chip complexity. It is anticipated that this methodology will provide a powerful tool for diagnostic applications that require rapid cost-effective detection of variations from known sequences. Images Fig. 1 Fig. 2 Fig. 3 PMID:7603999

  16. Localization of dense intracranial electrode arrays using magnetic resonance imaging

    PubMed Central

    Doyle, Werner K.; Halgren, Eric; Carlson, Chad; Belcher, Thomas L.; Cash, Sydney S.; Devinsky, Orrin; Thesen, Thomas

    2013-01-01

    Intracranial electrode arrays are routinely used in the pre-surgical evaluation of patients with medically refractory epilepsy, and recordings from these electrodes have been increasingly employed in human cognitive neurophysiology due to their high spatial and temporal resolution. For both researchers and clinicians, it is critical to localize electrode positions relative to the subject-specific neuroanatomy. In many centers, a post-implantation MRI is utilized for electrode detection because of its higher sensitivity for surgical complications and the absence of radiation. However, magnetic susceptibility artifacts surrounding each electrode prohibit unambiguous detection of individual electrodes, especially those that are embedded within dense grid arrays. Here, we present an efficient method to accurately localize intracranial electrode arrays based on pre- and post-implantation MR images that incorporates array geometry and the individual's cortical surface. Electrodes are directly visualized relative to the underlying gyral anatomy of the reconstructed cortical surface of individual patients. Validation of this approach shows high spatial accuracy of the localized electrode positions (mean of 0.96 mm±0.81 mm for 271 electrodes across 8 patients). Minimal user input, short processing time, and utilization of radiation-free imaging are strong incentives to incorporate quantitatively accurate localization of intracranial electrode arrays with MRI for research and clinical purposes. Co-registration to a standard brain atlas further allows inter-subject comparisons and relation of intracranial EEG findings to the larger body of neuroimaging literature. PMID:22759995

  17. Nano-fabricated pixelated micropolarizer array for visible imaging polarimetry

    SciTech Connect

    Zhang, Zhigang; Cheng, Teng; Qiu, Kang; Zhang, Qingchuan E-mail: wgchu@nanoctr.cn; Wu, Xiaoping; Dong, Fengliang; Chu, Weiguo E-mail: wgchu@nanoctr.cn

    2014-10-15

    Pixelated micropolarizer array (PMA) is a novel concept for real-time visible imaging polarimetry. A 320 × 240 aluminum PMA fabricated by electron beam lithography is described in this paper. The period, duty ratio, and depth of the grating are 140 nm, 0.5, and 100 nm, respectively. The units are standard square structures and the metal nanowires of the grating are collimating and uniformly thick. The extinction ratio of 75 and the maximum polarization transmittance of 78.8% demonstrate that the PMA is suitable for polarization imaging. When the PMA is applied to real-time polarization imaging, the degree of linear polarization image and the angle of linear polarization image are calculated from a single frame image. The polarized target object is highlighted from the unpolarized background, and the surface contour of the target object can be reflected by the polarization angle.

  18. Improved Phased Array Imaging of a Model Jet

    NASA Technical Reports Server (NTRS)

    Dougherty, Robert P.; Podboy, Gary G.

    2010-01-01

    An advanced phased array system, OptiNav Array 48, and a new deconvolution algorithm, TIDY, have been used to make octave band images of supersonic and subsonic jet noise produced by the NASA Glenn Small Hot Jet Acoustic Rig (SHJAR). The results are much more detailed than previous jet noise images. Shock cell structures and the production of screech in an underexpanded supersonic jet are observed directly. Some trends are similar to observations using spherical and elliptic mirrors that partially informed the two-source model of jet noise, but the radial distribution of high frequency noise near the nozzle appears to differ from expectations of this model. The beamforming approach has been validated by agreement between the integrated image results and the conventional microphone data.

  19. Active microelectronic array system for DNA hybridization, genotyping and pharmacogenomic applications.

    PubMed

    Sosnowski, Ron; Heller, Michael J; Tu, Eugene; Forster, Anita H; Radtkey, Ray

    2002-12-01

    Microelectronic arrays have been developed for DNA hybridization analysis of point mutations, single nucleotide polymorphisms, short tandem repeats and gene expression. In addition to a variety of molecular biology and genomic research applications, such devices will also be used for infectious disease detection, genetic and cancer diagnostics, and pharmacogenomic applications. These microelectronic array devices are able to produce defined electric fields on their surfaces that allow charged molecules and other entities to be transported to or from any test site or micro-location on the planar surface of the device. These molecules and entities include DNA, RNA, proteins, enzymes, antibodies and cells. Electronic-based molecule addressing and hybridization can then be carried out, where the electric field is now used to greatly accelerate the hybridization reactions that occur on the selected test sites. When reversed, the electric field can be used to provide an additional parameter for improved hybridization. Special low-conductance buffers have been developed that provide for the rapid transport of the DNA molecules and facilitate the electronic hybridization reactions under conditions that do not support hybridization. Important to the device function is the permeation layer that overcoats the underlying microelectrodes. Generally composed of a porous hydrogel material impregnated with attachment chemistry, this permeation layer prevents the destruction of analytes at the active microelectrode surface, ameliorates the adverse effects of electrolysis products on the sensitive hybridization and affinity reactions, and serves as a support structure for attaching DNA probes and other molecules to the array. The microelectronic chip or array device is incorporated into a cartridge package (NanoChip trade mark cartridge) that provides the electronic, optical, and fluidic interfacing. A complete instrument system (NanoChip trade mark Molecular Biology Workstation

  20. Image capture array with an organic light sensor

    SciTech Connect

    Street, R. A.; Mulato, M.; Lau, R.; Ho, J.; Graham, J.; Popovic, Z.; Hor, J.

    2001-06-25

    A large-area image capture device using an organic sensor is reported. The 512{times}512 pixel array, with 100{times}100 micrometer pixel size, combines amorphous silicon matrix addressing with a continuous organic sensor. The bilayer sensor comprises a tetraphenyldiamine hole transport layer on top of a benzimidazole perylene generator layer. This combination provides high sensitivity across the visible with low dark current. We present imaging properties and in particular show that the lateral charge transport between pixels is small, and that the effective fill factor is {similar_to}90%. X-ray imaging with a phosphor converter is demonstrated. {copyright} 2001 American Institute of Physics.

  1. Model Experiments with Slot Antenna Arrays for Imaging

    NASA Technical Reports Server (NTRS)

    Johansson, J. F.; Yngvesson, K. S.; Kollberg, E. L.

    1985-01-01

    A prototype imaging system at 31 GHz was developed, which employs a two-dimensional (5x5) array of tapered slot antennas, and integrated detector or mixer elements, in the focal plane of a prime-focus paraboloid reflector, with an f/D=1. The system can be scaled to shorter millimeter waves and submillimeter waves. The array spacing corresponds to a beam spacing of approximately one Rayleigh distance and a two-point resolution experiment showed that two point-sources at the Rayleigh distance are well resolved.

  2. Detectors based on silicon photomultiplier arrays for medical imaging applications

    SciTech Connect

    Llosa, G.; Barrio, J.; Cabello, J.; Lacasta, C.; Oliver, J. F.; Stankova, V.; Solaz, C.

    2011-07-01

    Silicon photomultipliers (SiPMs) have experienced a fast development and are now employed in different research fields. The availability of 2D arrays that provide information of the interaction position in the detector has had a high interest for medical imaging. Continuous crystals combined with segmented photodetectors can provide higher efficiency than pixellated crystals and very high spatial resolution. The IRIS group at IFIC is working on the development of detector heads based on continuous crystals coupled to SiPM arrays for different applications, including a small animal PET scanner in collaboration with the Univ. of Pisa and INFN Pisa, and a Compton telescope for dose monitoring in hadron therapy. (authors)

  3. Hybrid multispectral optoacoustic and ultrasound tomography for morphological and physiological brain imaging

    NASA Astrophysics Data System (ADS)

    Olefir, Ivan; Merčep, Elena; Burton, Neal C.; Ovsepian, Saak V.; Ntziachristos, Vasilis

    2016-08-01

    Expanding usage of small animal models in biomedical research necessitates development of technologies for structural, functional, or molecular imaging that can be readily integrated in the biological laboratory. Herein, we consider dual multispectral optoacoustic (OA) and ultrasound tomography based on curved ultrasound detector arrays and describe the performance achieved for hybrid morphological and physiological brain imaging of mice in vivo. We showcase coregistered hemodynamic parameters resolved by OA tomography under baseline conditions and during alterations of blood oxygen saturation. As an internal reference, we provide imaging of abdominal organs. We illustrate the performance advantages of hybrid curved detector ultrasound and OA tomography and discuss immediate and long-term implications of our findings in the context of animal and human studies.

  4. Depth-Enhanced Integral Imaging with a Stepped Lens Array or a Composite Lens Array for Three-Dimensional Display

    NASA Astrophysics Data System (ADS)

    Choi, Heejin; Park, Jae-Hyeung; Hong, Jisoo; Lee, Byoungho

    2004-08-01

    In spite of the many advantages of integral imaging, the depth of reconstructed three-dimensional (3D) image is limited to around the only one image plane. Here, we propose a novel method for increasing the depth of a reconstructed image using a stepped lens array (SLA) or a composite lens array (CLA). We confirm our idea by fabricating SLA and CLA with two image planes each. By using a SLA or a CLA, it is possible to form the 3D image around several image planes and to increase the depth of the reconstructed 3D image.

  5. Elliptical concave microlens arrays built in the photosensitive TiO2/ormosils hybrid films

    NASA Astrophysics Data System (ADS)

    Zhang, Xuehua; Que, Wenxiu; Javed, Hafiz M. Asif; Wei, Wei

    2014-11-01

    Photosensitive TiO2/organically modified silane hybrid thin films were prepared by a low-temperature sol-gel spin-coating technique. Optical and structural properties of the hybrid films with different titanium contents were characterized by prism coupling technique, UV-visible spectroscopy, Fourier transform infrared spectroscopy, and thermal gravimetric analysis. Advantages for fabrication of elliptical concave micro-lens arrays (MLAs) based on the as-prepared hybrid films were demonstrated by combining polydimethylsiloxane soft mold with a UV-cured imprint technique. Results indicate that the as-prepared hybrid films have great applicability for the fabrication of photonic components, and the fabrication technique provides a simple and cost-effective way for the fabrication of the sol-gel elliptical concave MLAs.

  6. Streptococcus pneumoniae Supragenome Hybridization Arrays for Profiling of Genetic Content and Gene Expression.

    PubMed

    Kadam, Anagha; Janto, Benjamin; Eutsey, Rory; Earl, Joshua P; Powell, Evan; Dahlgren, Margaret E; Hu, Fen Z; Ehrlich, Garth D; Hiller, N Luisa

    2015-02-02

    There is extensive genomic diversity among Streptococcus pneumoniae isolates. Approximately half of the comprehensive set of genes in the species (the supragenome or pangenome) is present in all the isolates (core set), and the remaining is unevenly distributed among strains (distributed set). The Streptococcus pneumoniae Supragenome Hybridization (SpSGH) array provides coverage for an extensive set of genes and polymorphisms encountered within this species, capturing this genomic diversity. Further, the capture is quantitative. In this manner, the SpSGH array allows for both genomic and transcriptomic analyses of diverse S. pneumoniae isolates on a single platform. In this unit, we present the SpSGH array, and describe in detail its design and implementation for both genomic and transcriptomic analyses. The methodology can be applied to construction and modification of SpSGH array platforms, as well to other bacterial species as long as multiple whole-genome sequences are available that collectively capture the vast majority of the species supragenome.

  7. Underwater hybrid near-field acoustical holography based on the measurement of vector hydrophone array

    NASA Astrophysics Data System (ADS)

    Hu, Bo; Yang, Desen; Sun, Yu

    2010-06-01

    Hybrid near-field acoustical holography (NAH) is developed for reconstructing acoustic radiation from a cylindrical source in a complex underwater environment. In hybrid NAH, we combine statistically optimized near-field acoustical holography (SONAH) and broadband acoustical holography from intensity measurements (BAHIM) to reconstruct the underwater cylindrical source field. First, the BAHIM is utilized to regenerate as much acoustic pressures on the hologram surface as necessary, and then the acoustic pressures are taken as input to the formulation implemented numerically by SONAH. The main advantages of this technology are that the complex pressure on the hologram surface can be reconstructed without reference signal, and the measurement array can be smaller than the source, thus the practicability and efficiency of this technology are greatly enhanced. Numerical examples of a cylindrical source are demonstrated. Test results show that hybrid NAH can yield a more accurate reconstruction than conventional NAH. Then, an experiment has been carried out with a vector hydrophone array. The experimental results show the advantage of hybrid NAH in the reconstruction of an acoustic field and the feasibility of using a vector hydrophone array in an underwater NAH measurement, as well as the identification and localization of noise sources.

  8. [Regularized inhomogeneity correction method for phased array image in magnetic resonance imaging].

    PubMed

    Guo, Hongyu; Pei, Xiaomin; Luo, Weitao; Dai, Jianpin

    2011-10-01

    Phased array coils (multiple receiver coil systems) have been extensively used for acquisition of MR images owing to their ability of increasing SNR, extending field-of-view (FOV), and reducing acquisition time. But the SOS algorithm,which is main method for phased array image reconstruction,will cause inhomogeneity in reconstructed image. A regularized least square method for phased array image combination is proposed in this paper. In the method, an additional reference scan is performed in advance. By using the reference scan, coil sensitivity map can be acquired, and image reconstructed from reference scan can be used as reference data in the regulation term. Experiments showed that the image uniformity was greatly improved by this method with scanning phantom and volunteer.

  9. Automated hybridization/imaging device for fluorescent multiplex DNA sequencing

    DOEpatents

    Weiss, Robert B.; Kimball, Alvin W.; Gesteland, Raymond F.; Ferguson, F. Mark; Dunn, Diane M.; Di Sera, Leonard J.; Cherry, Joshua L.

    1995-01-01

    A method is disclosed for automated multiplex sequencing of DNA with an integrated automated imaging hybridization chamber system. This system comprises an hybridization chamber device for mounting a membrane containing size-fractionated multiplex sequencing reaction products, apparatus for fluid delivery to the chamber device, imaging apparatus for light delivery to the membrane and image recording of fluorescence emanating from the membrane while in the chamber device, and programmable controller apparatus for controlling operation of the system. The multiplex reaction products are hybridized with a probe, then an enzyme (such as alkaline phosphatase) is bound to a binding moiety on the probe, and a fluorogenic substrate (such as a benzothiazole derivative) is introduced into the chamber device by the fluid delivery apparatus. The enzyme converts the fluorogenic substrate into a fluorescent product which, when illuminated in the chamber device with a beam of light from the imaging apparatus, excites fluorescence of the fluorescent product to produce a pattern of hybridization. The pattern of hybridization is imaged by a CCD camera component of the imaging apparatus to obtain a series of digital signals. These signals are converted by the controller apparatus into a string of nucleotides corresponding to the nucleotide sequence an automated sequence reader. The method and apparatus are also applicable to other membrane-based applications such as colony and plaque hybridization and Southern, Northern, and Western blots.

  10. Automated hybridization/imaging device for fluorescent multiplex DNA sequencing

    DOEpatents

    Weiss, R.B.; Kimball, A.W.; Gesteland, R.F.; Ferguson, F.M.; Dunn, D.M.; Di Sera, L.J.; Cherry, J.L.

    1995-11-28

    A method is disclosed for automated multiplex sequencing of DNA with an integrated automated imaging hybridization chamber system. This system comprises an hybridization chamber device for mounting a membrane containing size-fractionated multiplex sequencing reaction products, apparatus for fluid delivery to the chamber device, imaging apparatus for light delivery to the membrane and image recording of fluorescence emanating from the membrane while in the chamber device, and programmable controller apparatus for controlling operation of the system. The multiplex reaction products are hybridized with a probe, the enzyme (such as alkaline phosphatase) is bound to a binding moiety on the probe, and a fluorogenic substrate (such as a benzothiazole derivative) is introduced into the chamber device by the fluid delivery apparatus. The enzyme converts the fluorogenic substrate into a fluorescent product which, when illuminated in the chamber device with a beam of light from the imaging apparatus, excites fluorescence of the fluorescent product to produce a pattern of hybridization. The pattern of hybridization is imaged by a CCD camera component of the imaging apparatus to obtain a series of digital signals. These signals are converted by the controller apparatus into a string of nucleotides corresponding to the nucleotide sequence an automated sequence reader. The method and apparatus are also applicable to other membrane-based applications such as colony and plaque hybridization and Southern, Northern, and Western blots. 9 figs.

  11. 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.

  12. Uncooled infrared focal plane array imaging in China

    NASA Astrophysics Data System (ADS)

    Lei, Shuyu

    2015-06-01

    This article reviews the development of uncooled infrared focal plane array (UIFPA) imaging in China in the past decade. Sensors based on optical or electrical read-out mechanism were developed but the latter dominates the market. In resistive bolometers, VOx and amorphous silicon are still the two major thermal-sensing materials. The specifications of the IRFPA made by different manufactures were collected and compared. Currently more than five Chinese companies and institutions design and fabricate uncooled infrared focal plane array. Some devices have sensitivity as high as 30 mK; the largest array for commercial products is 640×512 and the smallest pixel size is 17 μm. Emphasis is given on the pixel MEMS design, ROIC design, fabrication, and packaging of the IRFPA manufactured by GWIC, especially on design for high sensitivities, low noise, better uniformity and linearity, better stabilization for whole working temperature range, full-digital design, etc.

  13. Large Imaging X-ray MKID Arrays for Astrophysics

    NASA Astrophysics Data System (ADS)

    Mazin, Benjamin

    Microwave Kinetic Inductance Detectors, or MKIDs, are a relatively new type of superconducting detector with built-in frequency domain multiplexing (FDM). Like Transition Edge Sensors (TESs), MKIDs can count single X-ray photons over a wide energy range and determine their energy and arrival time. Unlike TESs, MKIDs allow very large pixel counts with a fairly simple room temperature readout. MKIDs currently are being used for submillimeter/millimeter and optical/UV astronomy. They are a mature technology, and our group has recently demonstrated very promising X-ray MKIDs. The uncertain state of future NASA X-ray missions makes fundamental detector research even more important. New detector capabilities are one of the best ways to increase mission performance without increasing cost. We propose to continue our existing ROSES-funded program to develop X-ray MKIDs with the ultimate goal of developing large, sensitive focal plane arrays for future X-ray missions. In particular, we will focus on making a hybrid array with a core of high count rate, high energy resolution single pixels, and a very large (up to 50 mm x 50 mm, megapixel or larger) extended array with a moderate 5-15 eV energy resolution R=E/FWHM(E) at 6 keV. For the single pixel core of the array we propose a new type of "calorimetric" MKID that uses the temperature rise of a membrane suspended MKID and absorber, very similar in design to the TES detectors that have achieved an energy resolution of 1.8 eV at 5.9 keV. For the outer array the ability of absorber-coupled MKIDs to trap quasiparticles in a lower gap material allows the separation of the function of photon absorption from detection, and also allows distributed "strip detector/DROID" configurations that can drastically increase the size of the arrays. MKID arrays using rectangular 2-D detectors could quickly reach megapixel pixel counts and cover 25 cm^2. The science potential of a CCD-scale array but with 10-20 times better energy resolution is

  14. Discrete scintillator coupled mercuric iodide photodetector arrays for breast imaging

    SciTech Connect

    Tornai, M.P.; Levin, C.S.; Hoffman, E.J.

    1996-12-31

    Multi-element (4x4) imaging arrays with high resolution collimators, size matched to discrete CsI(Tl) scintillator arrays and mercuric iodide photodetector arrays (HgI{sub 2} PDA) are under development as prototypes for larger 16 x 16 element arrays. The compact nature of the arrays allows detector positioning in proximity to the breast to eliminate activity not in the line-of-sight of the collimator, thus reducing image background. Short collimators, size matched to {le}1.5 x 1.5 mm{sup 2} scintillators show a factor of 2 and 3.4 improvement in spatial resolution and efficiency, respectively, compared to high resolution collimated gamma cameras for the anticipated compressed breast geometries. Monte Carlo simulations, confirmed by measurements, demonstrated that scintillator length played a greater role in efficiency and photofraction for 140 keV gammas than cross sectional area, which affects intrinsic spatial resolution. Simulations also demonstrated that an increase in the ratio of scintillator area to length corresponds to an improvement in light collection. Electronic noise was below 40 e{sup -} RMS indicating that detector resolution was not noise limited. The high quantum efficiency and spectral match of prototype unity gain HgI{sub 2} PDAs coupled to 1 x 1 x 2.5 mm{sup 3} and 2 x 2 x 4 mm{sup 3} CsI(Tl) scintillators demonstrated energy resolutions of 9.4% and 8.8% FWHM at 140 keV, respectively, without the spectral tailing observed in standard high-Z, compound semi-conductor detectors. Line spread function measurements matched the scintillator size and pitch, and small, complex phantoms were easily imaged.

  15. A Hybrid Particle Swarm with Differential Evolution Operator Approach (DEPSO) for Linear Array Synthesis

    NASA Astrophysics Data System (ADS)

    Sarkar, Soham; Das, Swagatam

    In recent years particle swarm optimization emerges as one of the most efficient global optimization tools. In this paper, a hybrid particle swarm with differential evolution operator, termed DEPSO, is applied for the synthesis of linear array geometry. Here, the minimum side lobe level and null control, both are obtained by optimizing the spacing between the array elements by this technique. Moreover, a statistical comparison is also provided to establish its performance against the results obtained by Genetic Algorithm (GA), classical Particle Swarm Optimization (PSO), Tabu Search Algorithm (TSA), Differential Evolution (DE) and Memetic Algorithm (MA).

  16. Hybrid method for identifying mass groups of primary cosmic rays in the joint operation of IACTs and wide angle Cherenkov timing arrays

    NASA Astrophysics Data System (ADS)

    Postnikov, E. B.; Grinyuk, A. A.; Kuzmichev, L. A.; Sveshnikova, L. G.

    2017-01-01

    This work is a methodical study of another option of the hybrid method originally aimed at gamma/hadron separation in the TAIGA experiment. In the present paper this technique was performed to distinguish between different mass groups of cosmic rays in the energy range 200 TeV – 500 TeV. The study was based on simulation data of TAIGA prototype and included analysis of geometrical form of images produced by different nuclei in the IACT simulation as well as shower core parameters reconstructed using timing array simulation. We show that the hybrid method can be sufficiently effective to precisely distinguish between mass groups of cosmic rays.

  17. Separation of multiple images via directional guidance using structured prism and pyramid arrays.

    PubMed

    Lee, Hyemin; Seo, Hyein; Kang, Sunghwan; Yoon, Hyunsik

    2016-09-05

    We propose a new concept of separating images through a directional guide of multi-visuals by using structured prism or pyramid arrays. By placing prism arrays onto two different image arrays, the two collective images below the facets are guided to different directions. Using optical calculations, we identify a condition for successful image separation. Transparent pyramid arrays are used to separate four images into four directions. The direction of refracted rays can be controlled by the refractive index of prisms and liquid filled into the voids. In addition, the images can be switched by stretching and releasing an elastomeric prism array.

  18. Advanced indium antimonide monolithic charge coupled infrared imaging arrays

    NASA Technical Reports Server (NTRS)

    Koch, T. L.; Merilainen, C. A.; Thom, R. D.

    1981-01-01

    The continued process development of SiO2 insulators for use in advanced InSb monolithic charge coupled infrared imaging arrays is described. Specific investigations into the use of plasma enhanced chemical vapor deposited (PECVD) SiO2 as a gate insulator for InSb charge coupled devices is discussed, as are investigations of other chemical vapor deposited SiO2 materials.

  19. Fiber Scanning Array for 3 Dimensional Topographic Imaging

    NASA Technical Reports Server (NTRS)

    Coyle, D. Barry; Rabine, David L.; Poulios, Demetrios; Blair, J. Bryan; Stysley, Paul R.; Kay, Richard; Clarke, Greg; Bufton, Jack

    2013-01-01

    We report on the design and development of a fiber optic scanning 3-D LIDAR employing a switched fiber array. This design distributes ns length laser pulses over a sample field, collects the return pulses, and assembles them into a 3-D image. This instrument is a reduced size version consisting of 35 beams, and will serve as a proof-of-principle demonstration for a planned 1000 beam instrument for Earth and planetary topographical missions.

  20. A High-Efficiency Si Nanowire Array/Perovskite Hybrid Solar Cell.

    PubMed

    Yan, Xin; Zhang, Chen; Wang, Jiamin; Zhang, Xia; Ren, Xiaomin

    2017-12-01

    A low-cost Si nanowire array/perovskite hybrid solar cell is proposed and simulated. The solar cell consists of a Si p-i-n nanowire array filled with CH3NH3PbI3, in which both the nanowires and perovskite absorb the incident light while the nanowires act as the channels for transporting photo-generated electrons and holes. The hybrid structure has a high absorption efficiency in a broad wavelength range of 300~800 nm. A large short-circuit current density of 28.8 mA/cm(2) and remarkable conversion efficiency of 13.3% are obtained at a thin absorber thickness of 1.6 μm, which are comparable to the best results of III-V nanowire solar cells.

  1. A High-Efficiency Si Nanowire Array/Perovskite Hybrid Solar Cell

    NASA Astrophysics Data System (ADS)

    Yan, Xin; Zhang, Chen; Wang, Jiamin; Zhang, Xia; Ren, Xiaomin

    2017-01-01

    A low-cost Si nanowire array/perovskite hybrid solar cell is proposed and simulated. The solar cell consists of a Si p-i-n nanowire array filled with CH3NH3PbI3, in which both the nanowires and perovskite absorb the incident light while the nanowires act as the channels for transporting photo-generated electrons and holes. The hybrid structure has a high absorption efficiency in a broad wavelength range of 300 800 nm. A large short-circuit current density of 28.8 mA/cm2 and remarkable conversion efficiency of 13.3% are obtained at a thin absorber thickness of 1.6 μm, which are comparable to the best results of III-V nanowire solar cells.

  2. Holographic arrays for multi-path imaging artifact reduction

    DOEpatents

    McMakin, Douglas L.; Sheen, David M.; Hall, Thomas E.

    2007-11-13

    A method and apparatus to remove human features utilizing at least one transmitter transmitting a signal between 200 MHz and 1 THz, the signal having at least one characteristic of elliptical polarization, and at least one receiver receiving the reflection of the signal from the transmitter. A plurality of such receivers and transmitters are arranged together in an array which is in turn mounted to a scanner, allowing the array to be passed adjacent to the surface of the item being imaged while the transmitter is transmitting electromagnetic radiation. The array is passed adjacent to the surface of the item, such as a human being, that is being imaged. The portions of the received signals wherein the polarity of the characteristic has been reversed and those portions of the received signal wherein the polarity of the characteristic has not been reversed are identified. An image of the item from those portions of the received signal wherein the polarity of the characteristic was reversed is then created.

  3. Subwavelength optical imaging with an array of silver nanorods

    NASA Astrophysics Data System (ADS)

    Rahman, Atiqur; Kosulnikov, Sergey Yu.; Hao, Yang; Parini, Clive; Belov, Pavel A.

    2011-01-01

    Tailoring the parameters of a silver nanorod array for subwavelength imaging of arbitrary coherent sources is of recent interest. We evaluated the operational bandwidth of this type of superlens, and also the impact of source-offset in order to understand the level of tolerance offered by the superlens with regard to source location. The performance of the device was analyzed numerically both through analysis of transmission and reflection coefficients and by full-wave simulation for a particular sample source arrangement. We observed that such a device exhibited better imaging performances with the sources spread wider, offering a bandwidth of around 13.5%.

  4. Characteristics of Monolithically Integrated InGaAs Active Pixel Imager Array

    NASA Technical Reports Server (NTRS)

    Kim, Q.; Cunningham, T. J.; Pain, B.; Lange, M. J.; Olsen, G. H.

    2000-01-01

    Switching and amplifying characteristics of a newly developed monolithic InGaAs Active Pixel Imager Array are presented. The sensor array is fabricated from InGaAs material epitaxially deposited on an InP substrate. It consists of an InGaAs photodiode connected to InP depletion-mode junction field effect transistors (JFETs) for low leakage, low power, and fast control of circuit signal amplifying, buffering, selection, and reset. This monolithically integrated active pixel sensor configuration eliminates the need for hybridization with silicon multiplexer. In addition, the configuration allows the sensor to be front illuminated, making it sensitive to visible as well as near infrared signal radiation. Adapting the existing 1.55 micrometer fiber optical communication technology, this integration will be an ideal system of optoelectronic integration for dual band (Visible/IR) applications near room temperature, for use in atmospheric gas sensing in space, and for target identification on earth. In this paper, two different types of small 4 x 1 test arrays will be described. The effectiveness of switching and amplifying circuits will be discussed in terms of circuit effectiveness (leakage, operating frequency, and temperature) in preparation for the second phase demonstration of integrated, two-dimensional monolithic InGaAs active pixel sensor arrays for applications in transportable shipboard surveillance, night vision, and emission spectroscopy.

  5. Hybrid cryogenic low noise amplifier for the MeetKAT array

    NASA Astrophysics Data System (ADS)

    Jiang, Frank; Claude, Stephan; Garcia, Dominic

    2014-07-01

    Hybrid microwave integrated circuit technology is used to design and develop an L-band (900-2100 MHz) ultra-low noise amplifier for the MeerKAT array. This low noise amplifier achieved 2 K noise temperature, more than 40 dB gain, S11 & S22 better than -11 & -15 dB at 15 K ambient. Linearity and gain compression is verified. The noise performance is explored as the cooling temperature changes from 15 to 85 K.

  6. Complex direct comb spectroscopy with a virtually imaged phased array.

    PubMed

    Scholten, Sarah K; Anstie, James D; Hébert, Nicolas Bourbeau; White, Richard T; Genest, Jérôme; Luiten, Andre N

    2016-03-15

    We demonstrate a simple interferometric technique to directly measure the complex optical transmittance over a large spectral range using a frequency-comb spectrometer based on a virtually imaged phased array. A Michelson interferometer encodes the phase deviations induced by a sample contained in one of its arms into an interferogram image. When combined with an additional image taken from each arm separately, along with a frequency-calibration image, this allows full reconstruction of the sample's optical transfer function. We demonstrate the technique with a vapor cell containing H13C14N, producing transmittance and phase spectra spanning 2.9 THz (∼23  nm) with ∼1 GHz resolution.

  7. Stochastic segmentation models for array-based comparative genomic hybridization data analysis.

    PubMed

    Lai, Tze Leung; Xing, Haipeng; Zhang, Nancy

    2008-04-01

    Array-based comparative genomic hybridization (array-CGH) is a high throughput, high resolution technique for studying the genetics of cancer. Analysis of array-CGH data typically involves estimation of the underlying chromosome copy numbers from the log fluorescence ratios and segmenting the chromosome into regions with the same copy number at each location. We propose for the analysis of array-CGH data, a new stochastic segmentation model and an associated estimation procedure that has attractive statistical and computational properties. An important benefit of this Bayesian segmentation model is that it yields explicit formulas for posterior means, which can be used to estimate the signal directly without performing segmentation. Other quantities relating to the posterior distribution that are useful for providing confidence assessments of any given segmentation can also be estimated by using our method. We propose an approximation method whose computation time is linear in sequence length which makes our method practically applicable to the new higher density arrays. Simulation studies and applications to real array-CGH data illustrate the advantages of the proposed approach.

  8. Contact CMOS imaging of gaseous oxygen sensor array

    PubMed Central

    Daivasagaya, Daisy S.; Yao, Lei; Yi Yung, Ka; Hajj-Hassan, Mohamad; Cheung, Maurice C.; Chodavarapu, Vamsy P.; Bright, Frank V.

    2014-01-01

    We describe a compact luminescent gaseous oxygen (O2) sensor microsystem based on the direct integration of sensor elements with a polymeric optical filter and placed on a low power complementary metal-oxide semiconductor (CMOS) imager integrated circuit (IC). The sensor operates on the measurement of excited-state emission intensity of O2-sensitive luminophore molecules tris(4,7-diphenyl-1,10-phenanthroline) ruthenium(II) ([Ru(dpp)3]2+) encapsulated within sol–gel derived xerogel thin films. The polymeric optical filter is made with polydimethylsiloxane (PDMS) that is mixed with a dye (Sudan-II). The PDMS membrane surface is molded to incorporate arrays of trapezoidal microstructures that serve to focus the optical sensor signals on to the imager pixels. The molded PDMS membrane is then attached with the PDMS color filter. The xerogel sensor arrays are contact printed on top of the PDMS trapezoidal lens-like microstructures. The CMOS imager uses a 32 × 32 (1024 elements) array of active pixel sensors and each pixel includes a high-gain phototransistor to convert the detected optical signals into electrical currents. Correlated double sampling circuit, pixel address, digital control and signal integration circuits are also implemented on-chip. The CMOS imager data is read out as a serial coded signal. The CMOS imager consumes a static power of 320 µW and an average dynamic power of 625 µW when operating at 100 Hz sampling frequency and 1.8 V DC. This CMOS sensor system provides a useful platform for the development of miniaturized optical chemical gas sensors. PMID:24493909

  9. Contact CMOS imaging of gaseous oxygen sensor array.

    PubMed

    Daivasagaya, Daisy S; Yao, Lei; Yi Yung, Ka; Hajj-Hassan, Mohamad; Cheung, Maurice C; Chodavarapu, Vamsy P; Bright, Frank V

    2011-10-01

    We describe a compact luminescent gaseous oxygen (O2) sensor microsystem based on the direct integration of sensor elements with a polymeric optical filter and placed on a low power complementary metal-oxide semiconductor (CMOS) imager integrated circuit (IC). The sensor operates on the measurement of excited-state emission intensity of O2-sensitive luminophore molecules tris(4,7-diphenyl-1,10-phenanthroline) ruthenium(II) ([Ru(dpp)3](2+)) encapsulated within sol-gel derived xerogel thin films. The polymeric optical filter is made with polydimethylsiloxane (PDMS) that is mixed with a dye (Sudan-II). The PDMS membrane surface is molded to incorporate arrays of trapezoidal microstructures that serve to focus the optical sensor signals on to the imager pixels. The molded PDMS membrane is then attached with the PDMS color filter. The xerogel sensor arrays are contact printed on top of the PDMS trapezoidal lens-like microstructures. The CMOS imager uses a 32 × 32 (1024 elements) array of active pixel sensors and each pixel includes a high-gain phototransistor to convert the detected optical signals into electrical currents. Correlated double sampling circuit, pixel address, digital control and signal integration circuits are also implemented on-chip. The CMOS imager data is read out as a serial coded signal. The CMOS imager consumes a static power of 320 µW and an average dynamic power of 625 µW when operating at 100 Hz sampling frequency and 1.8 V DC. This CMOS sensor system provides a useful platform for the development of miniaturized optical chemical gas sensors.

  10. Synthesis of porous NiO/CeO2 hybrid nanoflake arrays as a platform for electrochemical biosensing

    NASA Astrophysics Data System (ADS)

    Cui, Jiewu; Luo, Jinbao; Peng, Bangguo; Zhang, Xinyi; Zhang, Yong; Wang, Yan; Qin, Yongqiang; Zheng, Hongmei; Shu, Xia; Wu, Yucheng

    2015-12-01

    Porous NiO/CeO2 hybrid nanoflake arrays fabricated by a facile hydrothermal method were employed as substrates for electrochemical biosensors. The resulting NiO/CeO2 hybrid nanoflake arrays with a large specific surface area and good biocompatibility presented an excellent platform for electrochemical biosensing.Porous NiO/CeO2 hybrid nanoflake arrays fabricated by a facile hydrothermal method were employed as substrates for electrochemical biosensors. The resulting NiO/CeO2 hybrid nanoflake arrays with a large specific surface area and good biocompatibility presented an excellent platform for electrochemical biosensing. Electronic supplementary information (ESI) available: Optical photographs of the as-prepared samples, SEM, TEM, EDS, XRD and BET data of the samples are presented, I-t curves of glucose biosensors based on NiO and NiO/CeO2 NFAs, EIS results of different electrodes. See DOI: 10.1039/c5nr05924k

  11. Optical simulations of P3HT/Si nanowire array hybrid solar cells.

    PubMed

    Wang, Wenbo; Li, Xinhua; Wen, Long; Zhao, Yufeng; Duan, Huahua; Zhou, Bukang; Shi, Tongfei; Zeng, Xuesong; Li, Ning; Wang, Yuqi

    2014-01-01

    An optical simulation of poly(3-hexylthiophene) (P3HT)/Si nanowire array (NWA) hybrid solar cells was investigated to evaluate the optical design requirements of the system by using finite-difference time-domain (FDTD) method. Steady improvement of light absorption was obtained with increased P3HT coating shell thickness from 0 to 80 nm on Si NWA. Further increasing the thickness caused dramatic decrease of the light absorption. Combined with the analysis of ultimate photocurrents, an optimum geometric structure with a coating P3HT thickness of 80 nm was proposed. At this structure, the hybrid solar cells show the most efficient light absorption. The optimization of the geometric structure and further understanding of the optical characteristics may contribute to the development for the practical experiment of the promising hybrid solar cells.

  12. Ion cyclotron and lower hybrid arrays applicable to current drive in fusion reactors

    SciTech Connect

    Bosia, G.; Ragona, R.; Helou, W.; Goniche, M.; Hillaret, J.

    2014-02-12

    This paper presents concepts for Ion Cyclotron and Lower Hybrid Current Drive arrays applicable to fusion reactors and based on periodically loaded line power division. It is shown that, in large arrays, such as the ones proposed for fusion reactor applications, these schemes can offer, in principle, a number of practical advantages, compared with currently adopted ones, such as in-blanket operation at significantly reduced power density, lay out suitable for water cooling, single ended or balanced power feed, simple and load independent impedance matching In addition, a remote and accurate real time measurement of the complex impedance of all array elements as well as detection, location, and measurement of the complex admittance of a single arc occurring anywhere in the structure is possible.

  13. Synchronization for an array of neural networks with hybrid coupling by a novel pinning control strategy.

    PubMed

    Gong, Dawei; Lewis, Frank L; Wang, Liping; Xu, Ke

    2016-05-01

    In this paper, a novel pinning synchronization (synchronization with pinning control) scheme for an array of neural networks with hybrid coupling is investigated. The main contributions are as follows: (1) A novel pinning control strategy is proposed for the first time. Pinning control schemes are introduced as an array of column vector. The controllers are designed as simple linear systems, which are easy to be analyzed or tested. (2) Augmented Lyapunov-Krasovskii functional (LKF) is applied to introduce more relax variables, which can alleviate the requirements of the positive definiteness of the matrix. (3) Based on the appropriate LKF, by introducing some free weighting matrices, some novel synchronization criteria are derived. Furthermore, the proposed pinning control scheme described by column vector can also be expanded to almost all the other array of neural networks. Finally, numerical examples are provided to show the effectiveness of the proposed results.

  14. A hybrid displacement estimation method for ultrasonic elasticity imaging.

    PubMed

    Chen, Lujie; Housden, R; Treece, Graham; Gee, Andrew; Prager, Richard

    2010-04-01

    Axial displacement estimation is fundamental to many freehand quasistatic ultrasonic strain imaging systems. In this paper, we present a novel estimation method that combines the strengths of quality-guided tracking, multi-level correlation, and phase-zero search to achieve high levels of accuracy and robustness. The paper includes a full description of the hybrid method, in vivo examples to illustrate the method's clinical relevance, and finite element simulations to assess its accuracy. Quantitative and qualitative comparisons are made with leading single- and multi-level alternatives. In the in vivo examples, the hybrid method produces fewer obvious peak-hopping errors, and in simulation, the hybrid method is found to reduce displacement estimation errors by 5 to 50%. With typical clinical data, the hybrid method can generate more than 25 strain images per second on commercial hardware; this is comparable with the alternative approaches considered in this paper.

  15. Oligonucleotide-directed self-assembly of proteins: semisynthetic DNA--streptavidin hybrid molecules as connectors for the generation of macroscopic arrays and the construction of supramolecular bioconjugates.

    PubMed Central

    Niemeyer, C M; Sano, T; Smith, C L; Cantor, C R

    1994-01-01

    Modified biomolecules were used for the non-covalent assembly of novel bioconjugates. Hybrid molecules were synthesized from short single-stranded DNA and streptavidin by chemical methods using a heterobispecific crosslinker. The covalent attachment of an oligonucleotide moiety to streptavidin provides a specific recognition domain for a complementary nucleic acid sequence, in addition to the four native biotin-binding sites. These bispecific binding capabilities allow the hybrid molecules to serve as versatile connectors in a variety of applications. Bifunctional constructs have been prepared from two complementary hybrid molecules, each previously conjugated to biotinylated immunoglobulin G or alkaline phosphatase. The use of nucleic acid sequences as a template for the formation of an array of proteins is further demonstrated on two size scales. A macroscopic DNA array on a microtiter plate has been transformed into a comparable protein chip. A nano-scale array was made by hybridizing DNA-tagged proteins to specific positions along a RNA or DNA sequence. The generation of supramolecular bioconjugates was shown by quantitative measurements and gel-retardation assays. Images PMID:7530841

  16. Two dimensional array imaging with beam steered data.

    PubMed

    Patole, Sujeet; Torlak, Murat

    2013-12-01

    This paper discusses different approaches used for millimeter wave imaging of 2D objects. Imaging of a 2D object requires reflected wave data to be collected across two distinct dimensions. In this paper, we propose a reconstruction method that uses narrowband waveforms along with 2D beam steering. The beam is steered in azimuthal and elevation direction, which forms the two distinct dimensions required for the reconstruction. The reconstruction technique uses inverse Fourier transform along with amplitude and phase correction factors. In addition, this reconstruction technique does not require interpolation of the data in either wavenumber or spatial domain. Use of the 2D beam steering offers better performance in the presence of noise compared with the existing methods, such as switched array imaging system. Effects of radio-frequency impairments such as quantization of the phase of beam steering weights and timing jitter, which add to phase noise, are analyzed.

  17. Development of a PET/Cerenkov-light hybrid imaging system

    SciTech Connect

    Yamamoto, Seiichi Hamamura, Fuka; Kato, Katsuhiko; Ogata, Yoshimune; Watabe, Tadashi; Ikeda, Hayato; Kanai, Yasukazu; Hatazawa, Jun; Watabe, Hiroshi

    2014-09-15

    Purpose: Cerenkov-light imaging is a new molecular imaging technology that detects visible photons from high-speed electrons using a high sensitivity optical camera. However, the merit of Cerenkov-light imaging remains unclear. If a PET/Cerenkov-light hybrid imaging system were developed, the merit of Cerenkov-light imaging would be clarified by directly comparing these two imaging modalities. Methods: The authors developed and tested a PET/Cerenkov-light hybrid imaging system that consists of a dual-head PET system, a reflection mirror located above the subject, and a high sensitivity charge coupled device (CCD) camera. The authors installed these systems inside a black box for imaging the Cerenkov-light. The dual-head PET system employed a 1.2 × 1.2 × 10 mm{sup 3} GSO arranged in a 33 × 33 matrix that was optically coupled to a position sensitive photomultiplier tube to form a GSO block detector. The authors arranged two GSO block detectors 10 cm apart and positioned the subject between them. The Cerenkov-light above the subject is reflected by the mirror and changes its direction to the side of the PET system and is imaged by the high sensitivity CCD camera. Results: The dual-head PET system had a spatial resolution of ∼1.2 mm FWHM and sensitivity of ∼0.31% at the center of the FOV. The Cerenkov-light imaging system's spatial resolution was ∼275μm for a {sup 22}Na point source. Using the combined PET/Cerenkov-light hybrid imaging system, the authors successfully obtained fused images from simultaneously acquired images. The image distributions are sometimes different due to the light transmission and absorption in the body of the subject in the Cerenkov-light images. In simultaneous imaging of rat, the authors found that {sup 18}F-FDG accumulation was observed mainly in the Harderian gland on the PET image, while the distribution of Cerenkov-light was observed in the eyes. Conclusions: The authors conclude that their developed PET/Cerenkov-light hybrid

  18. Rapid and specific detection of Lassa virus by reverse transcription-PCR coupled with oligonucleotide array hybridization.

    PubMed

    Olschläger, Stephan; Günther, Stephan

    2012-07-01

    To facilitate sequence-specific detection of DNA amplified in a diagnostic reverse transcription (RT)-PCR for Lassa virus, we developed an array featuring 47 oligonucleotide probes for post-PCR hybridization of the amplicons. The array procedure may be performed with low-tech equipment and does not take longer than agarose gel detection.

  19. Microfluidic Arrayed Lab-On-A-Chip for Electrochemical Capacitive Detection of DNA Hybridization Events.

    PubMed

    Ben-Yoav, Hadar; Dykstra, Peter H; Bentley, William E; Ghodssi, Reza

    2017-01-01

    A microfluidic electrochemical lab-on-a-chip (LOC) device for DNA hybridization detection has been developed. The device comprises a 3 × 3 array of microelectrodes integrated with a dual layer microfluidic valved manipulation system that provides controlled and automated capabilities for high throughput analysis of microliter volume samples. The surface of the microelectrodes is functionalized with single-stranded DNA (ssDNA) probes which enable specific detection of complementary ssDNA targets. These targets are detected by a capacitive technique which measures dielectric variation at the microelectrode-electrolyte interface due to DNA hybridization events. A quantitative analysis of the hybridization events is carried out based on a sensing modeling that includes detailed analysis of energy storage and dissipation components. By calculating these components during hybridization events the device is able to demonstrate specific and dose response sensing characteristics. The developed microfluidic LOC for DNA hybridization detection offers a technology for real-time and label-free assessment of genetic markers outside of laboratory settings, such as at the point-of-care or in-field environmental monitoring.

  20. Nanoparticle-nanocup hybrid array structure with a tunable sensitivity for colorimetric biosensing

    NASA Astrophysics Data System (ADS)

    Seo, Sujin; Liu, Gang L.

    2016-03-01

    Colorimetric detection is cost-effective and user-friendly when used for sensing target analytes without a need of bulky and expensive equipment. The extraordinary transmission phenomena through plasmonic periodic nanocup arrays achieve colorimetric sensing by detecting color changes of transmitted light associated with the refractive index variation. The application of the nanocup arrays, however, is relatively restricted due to a limited sensitivity for monolayered target analyte detections on the surface. In order to improve the sensitivity bounded by the underlying nanostructures, hybrid nanoparticle (NP) - nanocup array substrates are developed for enhancing the sensitivity to the refractive index change. The three dimensionally assembled Au NPs in circle along the sidewall of each nanocup increases the density of hot spots by the heterogeneous plasmonic coupling between the NP and the edge of the nanocup; thus a small refractive index change at the hot spot becomes easily detected than bare nanocup arrays. In addition to the bulk refractive index sensing, an ultrasensitive spectroscopic detection of the antigen-antibody binding is achieved by this three-dimensional self-assembly of Au NPs on the Au nanocup arrays.

  1. Radiometric infrared focal plane array imaging system for thermographic applications

    NASA Technical Reports Server (NTRS)

    Esposito, B. J.; Mccafferty, N.; Brown, R.; Tower, J. R.; Kosonocky, W. F.

    1992-01-01

    This document describes research performed under the Radiometric Infrared Focal Plane Array Imaging System for Thermographic Applications contract. This research investigated the feasibility of using platinum silicide (PtSi) Schottky-barrier infrared focal plane arrays (IR FPAs) for NASA Langley's specific radiometric thermal imaging requirements. The initial goal of this design was to develop a high spatial resolution radiometer with an NETD of 1 percent of the temperature reading over the range of 0 to 250 C. The proposed camera design developed during this study and described in this report provides: (1) high spatial resolution (full-TV resolution); (2) high thermal dynamic range (0 to 250 C); (3) the ability to image rapid, large thermal transients utilizing electronic exposure control (commandable dynamic range of 2,500,000:1 with exposure control latency of 33 ms); (4) high uniformity (0.5 percent nonuniformity after correction); and (5) high thermal resolution (0.1 C at 25 C background and 0.5 C at 250 C background).

  2. Gain calibrating nonuniform image-array data using only the image data

    NASA Technical Reports Server (NTRS)

    Kuhn, J. R.; Lin, H.; Loranz, D.

    1991-01-01

    An algorithm is developed for calibrating the spatial nonuniformity of image-array (CCD-type) detectors. Like other techniques this approach uses multiple, spatially displaced images. In circumstances where high-precision flat fields are not available by other means (i.e., sky flats) this technique is advantageous as it uses the data frames for gain calibration even when the array images extended, nonuniform, sources. Numerical experiments and direct observations with intrinsically uniform and quite nonuniform detectors show that this algorithm is useful when data frames are crowded with sources - circumstance where 'median filtering' flatfielding techniques often fail. The algorithm described is robust and efficiently uses information from multiple data frames to determine pixel gain variations, using visible and IR array observations of extended sources.

  3. Optical-digital hybrid image search system in cloud environment

    NASA Astrophysics Data System (ADS)

    Ikeda, Kanami; Kodate, Kashiko; Watanabe, Eriko

    2016-09-01

    To improve the versatility and usability of optical correlators, we developed an optical-digital hybrid image search system consisting of digital servers and an optical correlator that can be used to perform image searches in the cloud environment via a web browser. This hybrid system employs a simple method to obtain correlation signals and has a distributed network design. The correlation signals are acquired by using an encoder timing signal generated by a rotating disk, and the distributed network design facilitates the replacement and combination of the digital correlation server and the optical correlator.

  4. 4K×4K format 10μm pixel pitch H4RG-10 hybrid CMOS silicon visible focal plane array for space astronomy

    NASA Astrophysics Data System (ADS)

    Bai, Yibin; Tennant, William; Anglin, Selmer; Wong, Andre; Farris, Mark; Xu, Min; Holland, Eric; Cooper, Donald; Hosack, Joseph; Ho, Kenneth; Sprafke, Thomas; Kopp, Robert; Starr, Brian; Blank, Richard; Beletic, James W.; Luppino, Gerard A.

    2012-07-01

    Teledyne’s silicon hybrid CMOS focal plane array technology has matured into a viable, high performance and high- TRL alternative to scientific CCD sensors for space-based applications in the UV-visible-NIR wavelengths. This paper presents the latest results from Teledyne’s low noise silicon hybrid CMOS visible focal place array produced in 4K×4K format with 10 μm pixel pitch. The H4RG-10 readout circuit retains all of the CMOS functionality (windowing, guide mode, reference pixels) and heritage of its highly successful predecessor (H2RG) developed for JWST, with additional features for improved performance. Combined with a silicon PIN detector layer, this technology is termed HyViSI™ (Hybrid Visible Silicon Imager). H4RG-10 HyViSI™ arrays achieve high pixel interconnectivity (<99.99%), low readout noise (<10 e- rms single CDS), low dark current (<0.5 e-/pixel/s at 193K), high quantum efficiency (<90% broadband), and large dynamic range (<13 bits). Pixel crosstalk and interpixel capacitance (IPC) have been predicted using detailed models of the hybrid structure and these predictions have been confirmed by measurements with Fe-55 Xray events and the single pixel reset technique. For a 100-micron thick detector, IPC of less than 3% and total pixel crosstalk of less than 7% have been achieved for the HyViSI™ H4RG-10. The H4RG-10 array is mounted on a lightweight silicon carbide (SiC) package and has been qualified to Technology Readiness Level 6 (TRL-6). As part of space qualification, the HyViSI™ H4RG-10 array passed radiation testing for low earth orbit (LEO) environment.

  5. Inorganic/organic hybrid solar cells: optimal carrier transport in vertically aligned silicon nanowire arrays

    NASA Astrophysics Data System (ADS)

    Sato, Keisuke; Dutta, Mrinal; Fukata, Naoki

    2014-05-01

    Inorganic/organic hybrid radial heterojunction solar cells that combine vertically-aligned n-type silicon nanowires (SiNWs) with poly(3,4-ethylenedioxythiophene):poly(styrene-sulfonate) (PEDOT:PSS) have great potential for replacing commercial Si solar cells. The chief advantage of such solar cells is that they exhibit higher absorbance for a given thickness than commercial Si solar cells, due to incident light-trapping within the NW arrays, thus enabling lower-cost solar cell production. We report herein on the effects of NW length, annealing and surface electrode on the device performance of SiNW/PEDOT:PSS hybrid radial heterojunction solar cells. The power conversion efficiency (PCE) of the obtained SiNW/PEDOT:PSS hybrid solar cells can be optimized by tuning the thickness of the surface electrode, and the etching conditions during NW formation and post-annealing. The PCE of 9.3% is obtained by forming efficient transport pathways for photogenerated charge carriers to electrodes. Our approach is a significant contribution to design of high-performance and low-cost inorganic/organic hybrid heterojunction solar cells.Inorganic/organic hybrid radial heterojunction solar cells that combine vertically-aligned n-type silicon nanowires (SiNWs) with poly(3,4-ethylenedioxythiophene):poly(styrene-sulfonate) (PEDOT:PSS) have great potential for replacing commercial Si solar cells. The chief advantage of such solar cells is that they exhibit higher absorbance for a given thickness than commercial Si solar cells, due to incident light-trapping within the NW arrays, thus enabling lower-cost solar cell production. We report herein on the effects of NW length, annealing and surface electrode on the device performance of SiNW/PEDOT:PSS hybrid radial heterojunction solar cells. The power conversion efficiency (PCE) of the obtained SiNW/PEDOT:PSS hybrid solar cells can be optimized by tuning the thickness of the surface electrode, and the etching conditions during NW formation and

  6. Damage assessment in hybrid laminates using an array of embedded fiber optic sensors

    NASA Astrophysics Data System (ADS)

    Austin, Timothy S. P.; Singh, Margaret M.; Gregson, Peter J.; Dakin, John P.; Powell, Philip M.

    1999-05-01

    Hybrid laminates typically consist of alternate layers of fiber-reinforced polymer and aluminium alloy. Developed primarily for fatigue critical aerospace applications, the hybrid laminates are orthotropic materials with lower density and higher strength compared to the aluminium alloy monolith. One of the damage mechanism of particular interest is that of fatigue crack growth, which for hybrid laminates is a relatively complex process that includes a combination of delamination and fiber bridging. To facilitate the development of a unified model for both crack and damage growth processes, a remote sensing system, reliant upon fiber optic sensor technology, has been utilized to monitor strain within the composite layer. The fiber optic system, with capacity for sub microstrain resolution, combines time domain multiplexing with line switching to monitor continuously an array of Bragg grating sensors. Herein are detailed the findings from a study performed using an array of 40 sensors distributed across a small area of a test price containing a fatigue crack initiated at a through- thickness fastener hole. Together with details of system operation, sensor measurements of the strain profiles associated with the developing delamination zone are reported.

  7. Modeling of hybridized infrared arrays for characterization of interpixel capacitive coupling

    NASA Astrophysics Data System (ADS)

    Donlon, Kevan; Ninkov, Zoran; Baum, Stefi; Cheng, Linpeng

    2017-02-01

    Interpixel capacitance (IPC) is a deterministic electronic coupling resulting in a portion of signal incident on one pixel of a hybridized detector array being measured in adjacent pixels. Data collected by light sensitive HgCdTe arrays that exhibit this coupling typically goes uncorrected or is corrected by treating the coupling as a fixed point spread function. Evidence suggests that this coupling is not uniform across signal and background levels. Subarrays of pixels using design parameters based upon HgCdTe indium hybridized arrays akin to those contained in the James Webb Space Telescope's NIRcam have been modeled from first principles using Lumerical DEVICE Software. This software simultaneously solves Poisson's equation and the drift diffusion equations yielding charge distributions and electric fields. Modeling of this sort generates the local point spread function across a range of detector parameters. This results in predictive characterization of IPC across scene and device parameters that would permit proper photometric correction and signal restoration to the data. Additionally, the ability to visualize potential distributions and couplings as generated by the models yields insight that can be used to minimize IPC coupling in the design of future detectors.

  8. Ultrafast dynamics of metal plasmons induced by 2D semiconductor excitons in hybrid nanostructure arrays

    DOE PAGES

    Boulesbaa, Abdelaziz; Babicheva, Viktoriia E.; Wang, Kai; ...

    2016-11-17

    With the advanced progress achieved in the field of nanotechnology, localized surface plasmons resonances (LSPRs) are actively considered to improve the efficiency of metal-based photocatalysis, photodetection, and photovoltaics. Here, we report on the exchange of energy and electric charges in a hybrid composed of a two-dimensional tungsten disulfide (2D-WS2) monolayer and an array of aluminum (Al) nanodisks. Femtosecond pump-probe spectroscopy results indicate that within ~830 fs after photoexcitation of the 2D-WS2 semiconductor, energy transfer from the 2D-WS2 excitons excites the plasmons of the Al array. Then, upon the radiative and/or nonradiative damping of these excited plasmons, energy and/or electron transfermore » back to the 2D-WS2 semiconductor takes place as indicated by an increase in the reflected probe at the 2D exciton transition energies at later time-delays. This simultaneous exchange of energy and charges between the metal and the 2D-WS2 semiconductor resulted in an extension of the average lifetime of the 2D-excitons from ~15 to ~58 ps in absence and presence of the Al array, respectively. Furthermore, the indirectly excited plasmons were found to live as long as the 2D-WS2 excitons exist. Furthermore, the demonstrated ability to generate exciton-plasmons coupling in a hybrid nanostructure may open new opportunities for optoelectronic applications such as plasmonic-based photodetection and photocatalysis.« less

  9. Hybrid micro-/nanogels for optical sensing and intracellular imaging

    PubMed Central

    Wu, Weitai; Zhou, Shuiqin

    2010-01-01

    Hybrid micro-/nanogels are playing an increasing important part in a diverse range of applications, due to their tunable dimensions, large surface area, stable interior network structure, and a very short response time. We review recent advances and challenges in the developments of hybrid micro-/nanogels toward applications for optical sensing of pH, temperature, glucose, ions, and other species as well as for intracellular imaging. Due to their unique advantages, hybrid micro-/nanogels as optical probes are attracting substantial interests for continuous monitoring of chemical parameters in complex samples such as blood and bioreactor fluids, in chemical research and industry, and in food quality control. In particular, their intracellular probing ability enables the monitoring of the biochemistry and biophysics of live cells over time and space, thus contributing to the explanation of intricate biological processes and the development of novel diagnoses. Unlike most other probes, hybrid micro-/nanogels could also combine other multiple functions into a single probe. The rational design of hybrid micro-/nanogels will not only improve the probing applications as desirable, but also implement their applications in new arenas. With ongoing rapid advances in bionanotechnology, the well-designed hybrid micro-/nanogel probes will be able to provide simultaneous sensing, imaging diagnosis, and therapy toward clinical applications. PMID:22110866

  10. X-ray imaging using a 320 x 240 hybrid GaAs pixel detector

    SciTech Connect

    Irsigler, R.; Andersson, J.; Alverbro, J.

    1999-06-01

    The authors present room temperature measurements on 200 {micro}m thick GaAs pixel detectors, which were hybridized to silicon readout circuits. The whole detector array contains 320 x 240 square shaped pixel with a pitch of 38 {micro}m and is based on semi-insulating liquid-encapsulated Czochralski (LEC) GaAs material. After fabricating and dicing, the detector chips were indium bump flip chip bonded to CMOS readout circuits based on charge integration and finally evaluated. This readout chip was originally designed for the readout of flip chip bonded infrared detectors, but appears to be suitable for X-ray applications as well. A bias voltage between 50 V and 100 V was sufficient to operate the detector at room temperature. The detector array did respond to x-ray radiation by an increase in current due to production of electron hole pairs by the ionization processes. Images of various objects and slit patterns were acquired by using a standard X-ray source for dental imaging. The new X-ray hybrid detector was analyzed with respect to its imaging properties. Due to the high absorption coefficient for X-rays in GaAs and the small pixel size, the sensor shows a high modulation transfer function up to the Nyquist frequency.

  11. Guided Wave Annular Array Sensor Design for Improved Tomographic Imaging

    NASA Astrophysics Data System (ADS)

    Koduru, Jaya Prakash; Rose, Joseph L.

    2009-03-01

    Guided wave tomography for structural health monitoring is fast emerging as a reliable tool for the detection and monitoring of hotspots in a structure, for any defects arising from corrosion, crack growth etc. To date guided wave tomography has been successfully tested on aircraft wings, pipes, pipe elbows, and weld joints. Structures practically deployed are subjected to harsh environments like exposure to rain, changes in temperature and humidity. A reliable tomography system should take into account these environmental factors to avoid false alarms. The lack of mode control with piezoceramic disk sensors makes it very sensitive to traces of water leading to false alarms. In this study we explore the design of annular array sensors to provide mode control for improved structural tomography, in particular, addressing the false alarm potential of water loading. Clearly defined actuation lines in the phase velocity dispersion curve space are calculated. A dominant in-plane displacement point is found to provide a solution to the water loading problem. The improvement in the tomographic images with the annular array sensors in the presence of water traces is clearly illustrated with a series of experiments. An annular array design philosophy for other problems in NDE/SHM is also discussed.

  12. Prototype AEGIS: A Pixel-Array Readout Circuit for Gamma-Ray Imaging

    PubMed Central

    Barber, H. Bradford; Augustine, F. L.; Furenlid, L.; Ingram, C. M.; Grim, G. P.

    2015-01-01

    Semiconductor detector arrays made of CdTe/CdZnTe are expected to be the main components of future high-performance, clinical nuclear medicine imaging systems. Such systems will require small pixel-pitch and much larger numbers of pixels than are available in current semiconductor-detector cameras. We describe the motivation for developing a new readout integrated circuit, AEGIS, for use in hybrid semiconductor detector arrays, that may help spur the development of future cameras. A basic design for AEGIS is presented together with results of an HSPICE™ simulation of the performance of its unit cell. AEGIS will have a shaper-amplifier unit cell and neighbor pixel readout. Other features include the use of a single input power line with other biases generated on-board, a control register that allows digital control of all thresholds and chip configurations and an output approach that is compatible with list-mode data acquisition. An 8×8 prototype version of AEGIS is currently under development; the full AEGIS will be a 64×64 array with 300 μm pitch. PMID:26345126

  13. Characteristics of Monolithically Integrated InGaAs Active Pixel Image Array

    NASA Technical Reports Server (NTRS)

    Kim, Q.; Cunningham, T. J.; Pain, B.; Lange, M. J.; Olsen, G. H.

    1999-01-01

    Switching and amplifying characteristics of a newly developed monolithic InGaAs Active Pixel Imager Array are presented. The sensor array is fabricated from InGaAs material epitaxially deposited on an InP substrate.

  14. Deep-penetration photoacoustic array imaging of calcifications

    NASA Astrophysics Data System (ADS)

    Hsiao, Tsai-Chu; Cheng, Yao-Yu; Tein, Wan-Ting; Luo, Shih-Bin; Chiou, De-Yi; Chung, Ren-Jei; Li, Meng-Lin

    2013-06-01

    Calcifications are one of the most important indicators for early breast cancer detection. We explore the feasibility of deep-penetration photoacoustic (PA) imaging of calcifications based on a medical ultrasound array imaging platform. Intralipid and chicken breast phantoms embedded with different-sized hydroxyapatite (HA) particles, which are the major components of calcifications, were imaged to verify the equipment's capability and penetration depth for the visualization of calcifications. An optimal near-infrared excitation wavelength was selected to maximize PA signals of HAs, resulting in a better HA signal-to-blood ratio. We demonstrated that PA imaging is capable of visualizing 0.5-mm HA particles at a depth of 3 cm in chicken breast phantoms. The noise-equivalent penetration depth of the system for visualizing 0.5-mm HA particles in the human breast was estimated to be about 2.9 to 3.5 cm, which is clinically relevant as calcifications are usually found at a depth of 0.6 to 3.0 cm. Moreover, the feasibility of differentiating HA from blood by the PA spectroscopic technique was presented and the mechanism of the HA signal generation was discussed. The results show that PA imaging is a promising technique for real-time visualization of breast calcifications.

  15. Breadboard linear array scan imager using LSI solid-state technology

    NASA Technical Reports Server (NTRS)

    Tracy, R. A.; Brennan, J. A.; Frankel, D. G.; Noll, R. E.

    1976-01-01

    The performance of large scale integration photodiode arrays in a linear array scan (pushbroom) breadboard was evaluated for application to multispectral remote sensing of the earth's resources. The technical approach, implementation, and test results of the program are described. Several self scanned linear array visible photodetector focal plane arrays were fabricated and evaluated in an optical bench configuration. A 1728-detector array operating in four bands (0.5 - 1.1 micrometer) was evaluated for noise, spectral response, dynamic range, crosstalk, MTF, noise equivalent irradiance, linearity, and image quality. Other results include image artifact data, temporal characteristics, radiometric accuracy, calibration experience, chip alignment, and array fabrication experience. Special studies and experimentation were included in long array fabrication and real-time image processing for low-cost ground stations, including the use of computer image processing. High quality images were produced and all objectives of the program were attained.

  16. Si/PEDOT hybrid core/shell nanowire arrays as photoelectrodes for photoelectrochemical water-splitting.

    PubMed

    Li, Xiaojuan; Lu, Wenhui; Dong, Weiling; Chen, Qi; Wu, Dan; Zhou, Wenzheng; Chen, Liwei

    2013-06-21

    Si/poly(3,4-ethylenedioxythiophene) (PEDOT) core/shell nanowire arrays have been prepared by chemical etching of Si nanowires followed by vapor-phase polymerization of PEDOT as hybrid photoanodes for photoelectrochemical water-splitting. The PEDOT layer is employed as a multi-functional coating to prevent photocorrosion of Si nanowires, collect photogenerated holes and catalyze the water oxidation reaction. The amino silane modified Si nanowire surface improves PEDOT layer adhesion, and the resulting photoanode exhibits better photoresponse and improved stability. By tuning the length of the nanowires, we identify that the competition between the carrier recombination and catalytic water oxidation reaction is the primary factor determining the photoelectrocatalytic activity of the hybrid photoanode.

  17. Phased Acoustic Array Measurements of a 5.75 Percent Hybrid Wing Body Aircraft

    NASA Technical Reports Server (NTRS)

    Burnside, Nathan J.; Horne, William C.; Elmer, Kevin R.; Cheng, Rui; Brusniak, Leon

    2016-01-01

    Detailed acoustic measurements of the noise from the leading-edge Krueger flap of a 5.75 percent Hybrid Wing Body (HWB) aircraft model were recently acquired with a traversing phased microphone array in the AEDC NFAC (Arnold Engineering Development Complex, National Full Scale Aerodynamics Complex) 40- by 80-Foot Wind Tunnel at NASA Ames Research Center. The spatial resolution of the array was sufficient to distinguish between individual support brackets over the full-scale frequency range of 100 to 2875 Hertz. For conditions representative of landing and take-off configuration, the noise from the brackets dominated other sources near the leading edge. Inclusion of flight-like brackets for select conditions highlights the importance of including the correct number of leading-edge high-lift device brackets with sufficient scale and fidelity. These measurements will support the development of new predictive models.

  18. Hyperspectral Image Recovery via Hybrid Regularization

    NASA Astrophysics Data System (ADS)

    Arablouei, Reza; de Hoog, Frank

    2016-12-01

    Natural images tend to mostly consist of smooth regions with individual pixels having highly correlated spectra. This information can be exploited to recover hyperspectral images of natural scenes from their incomplete and noisy measurements. To perform the recovery while taking full advantage of the prior knowledge, we formulate a composite cost function containing a square-error data-fitting term and two distinct regularization terms pertaining to spatial and spectral domains. The regularization for the spatial domain is the sum of total-variation of the image frames corresponding to all spectral bands. The regularization for the spectral domain is the l1-norm of the coefficient matrix obtained by applying a suitable sparsifying transform to the spectra of the pixels. We use an accelerated proximal-subgradient method to minimize the formulated cost function. We analyze the performance of the proposed algorithm and prove its convergence. Numerical simulations using real hyperspectral images exhibit that the proposed algorithm offers an excellent recovery performance with a number of measurements that is only a small fraction of the hyperspectral image data size. Simulation results also show that the proposed algorithm significantly outperforms an accelerated proximal-gradient algorithm that solves the classical basis-pursuit denoising problem to recover the hyperspectral image.

  19. Hyperspectral Image Recovery via Hybrid Regularization.

    PubMed

    Arablouei, Reza; de Hoog, Frank

    2016-09-27

    Natural images tend to mostly consist of smooth regions with individual pixels having highly correlated spectra. This information can be exploited to recover hyperspectral images of natural scenes from their incomplete and noisy measurements. To perform the recovery while taking full advantage of the prior knowledge, we formulate a composite cost function containing a square-error data-fitting term and two distinct regularization terms pertaining to spatial and spectral domains. The regularization for the spatial domain is the sum of total-variation of the image frames corresponding to all spectral bands. The regularization for the spectral domain is the ��������-norm of the coefficient matrix obtained by applying a suitable sparsifying transform to the spectra of the pixels. We use an accelerated proximal-subgradient method to minimize the formulated cost function. We analyse the performance of the proposed algorithm and prove its convergence. Numerical simulations using real hyperspectral images exhibit that the proposed algorithm offers an excellent recovery performance with a number of measurements that is only a small fraction of the hyperspectral image data size. Simulation results also show that the proposed algorithm significantly outperforms an accelerated proximal-gradient algorithm that solves the classical basis-pursuit denoising problem to recover the hyperspectral image.

  20. Inorganic/organic hybrid solar cells: optimal carrier transport in vertically aligned silicon nanowire arrays.

    PubMed

    Sato, Keisuke; Dutta, Mrinal; Fukata, Naoki

    2014-06-07

    Inorganic/organic hybrid radial heterojunction solar cells that combine vertically-aligned n-type silicon nanowires (SiNWs) with poly(3,4-ethylenedioxythiophene):poly(styrene-sulfonate) (PEDOT:PSS) have great potential for replacing commercial Si solar cells. The chief advantage of such solar cells is that they exhibit higher absorbance for a given thickness than commercial Si solar cells, due to incident light-trapping within the NW arrays, thus enabling lower-cost solar cell production. We report herein on the effects of NW length, annealing and surface electrode on the device performance of SiNW/PEDOT:PSS hybrid radial heterojunction solar cells. The power conversion efficiency (PCE) of the obtained SiNW/PEDOT:PSS hybrid solar cells can be optimized by tuning the thickness of the surface electrode, and the etching conditions during NW formation and post-annealing. The PCE of 9.3% is obtained by forming efficient transport pathways for photogenerated charge carriers to electrodes. Our approach is a significant contribution to design of high-performance and low-cost inorganic/organic hybrid heterojunction solar cells.

  1. Enhanced light absorption of silicon nanotube arrays for organic/inorganic hybrid solar cells.

    PubMed

    Jeong, Huisu; Song, Hui; Pak, Yusin; Kwon, Il Keun; Jo, Kyubong; Lee, Heon; Jung, Gun Young

    2014-06-04

    By combining nanoimprint lithography technique and a two-step lift-off process, a Si nanotube array is fabricated and applied as a light absorber for n-Si/PEDOT:PSS hybrid solar cells. The light is effectively trapped within the nanotubes and the device reveals a Jsc of 29.9 mA · cm(-2) and a power conversion efficiency of 10.03%, which is an enhancement of 13.4% compared to the cell having the best-known Si architecture of nanocones as a light absorber to date.

  2. Microphone matching for hybrid-order directional arrays in hearing aid applications

    NASA Astrophysics Data System (ADS)

    Warren, Daniel M.; Thompson, Steve C.

    2003-04-01

    The ability of a hearing aid user to distinguish a single speech source amidst general background noise (for example, dinner table or cocktail party conversation) may be improved by a directional array of microphones in the hearing instrument. The theoretical maximum directivity index (DI) of a first-order pairing of microphones is 6 dB, and a second-order array of three microphones is 9.5 dB, assuming all three microphones have identical frequency responses. The close spacing of microphone ports in a hearing aid body means that directivity degrades rapidly with differences in microphone sensitivities. A hybrid of first- and second-order arrays can mitigate this effect, although close microphone matching is still necessary for high directivity. This paper explores the effect of microphone mismatch on the directivity of such arrays, and describes practical criteria for selecting matched microphones out of production batches to maximize a speech intelligibility weighted directivity index. [Work supported by Knowles Electronics, LLC.

  3. Hybrid Extensive Air Shower Detector Array at the University of Puebla to Study Cosmic Rays

    NASA Astrophysics Data System (ADS)

    Martínez, O.; Pérez, E.; Salazar, H.; Villaseñor, L.

    We describe the design of an extensive air shower detector array built in the Campus of the University of Puebla (located at 19°N, 90°W, 800 gcm -2) to measure the energy and arrival direction of primary cosmic rays with energies around 1015 eV. The array consists of 18 liquid scintillator detectors (12 in the first stage) and 6 water Cherenkov detectors (one of 10 m 2 cross section and five smaller ones of 1.86 m 2 cross section), distributed in a square grid with a detector spacing of 20 m over an area of 4000 m 2. In this paper we discuss the calibration and stability of the array, and discuss the capability of hybrid arrays, such as this one consisting of water Cherenkov and liquid scintillator detectors, to allow a separation of the electromagnetic and muon components of extensive air showers. This separation plays an important role in the determination of the mass and identity of the primary cosmic ray. This facility is also used to train students interested in the field of cosmic rays.

  4. Using Array-Based Comparative Genomic Hybridization to Diagnose Pallister-Killian Syndrome

    PubMed Central

    Lee, Mi-Na; Lee, Jiwon; Yu, Hee Joon; Lee, Jeehun

    2017-01-01

    Pallister-Killian syndrome (PKS) is a rare multisystem disorder characterized by isochromosome 12p and tissue-limited mosaic tetrasomy 12p. In this study, we diagnosed three pediatric patients who were suspicious of having PKS using array-based comparative genomic hybridization (array CGH) and FISH analyses performed on peripheral lymphocytes. Patients 1 and 2 presented with craniofacial dysmorphic features, hypotonia, and a developmental delay. Array CGH revealed two to three copies of 12p in patient 1 and three copies in patient 2. FISH analysis showed trisomy or tetrasomy 12p. Patient 3, who had clinical features comparable to those of patients 1 and 2, was diagnosed by using FISH analysis alone. Here, we report three patients with mosaic tetrasomy 12p. There have been only reported cases diagnosed by chromosome analysis and FISH analysis on skin fibroblast or amniotic fluid. To our knowledge, patient 1 was the first case diagnosed by using array CGH performed on peripheral lymphocytes in Korea. PMID:27834069

  5. Using Array-Based Comparative Genomic Hybridization to Diagnose Pallister-Killian Syndrome.

    PubMed

    Lee, Mi Na; Lee, Jiwon; Yu, Hee Joon; Lee, Jeehun; Kim, Sun Hee

    2017-01-01

    Pallister-Killian syndrome (PKS) is a rare multisystem disorder characterized by isochromosome 12p and tissue-limited mosaic tetrasomy 12p. In this study, we diagnosed three pediatric patients who were suspicious of having PKS using array-based comparative genomic hybridization (array CGH) and FISH analyses performed on peripheral lymphocytes. Patients 1 and 2 presented with craniofacial dysmorphic features, hypotonia, and a developmental delay. Array CGH revealed two to three copies of 12p in patient 1 and three copies in patient 2. FISH analysis showed trisomy or tetrasomy 12p. Patient 3, who had clinical features comparable to those of patients 1 and 2, was diagnosed by using FISH analysis alone. Here, we report three patients with mosaic tetrasomy 12p. There have been only reported cases diagnosed by chromosome analysis and FISH analysis on skin fibroblast or amniotic fluid. To our knowledge, patient 1 was the first case diagnosed by using array CGH performed on peripheral lymphocytes in Korea.

  6. First Data with the Hybrid Array of Gamma-Ray Detectors (HAGRiD)

    NASA Astrophysics Data System (ADS)

    Smith, Karl; Burcher, S.; Carter, A. B.; Gryzwacz, R.; Jones, K. L.; Munoz, S.; Paulauskas, S. V.; Schmitt, K.; Thornsberry, C.; Chipps, K. A.; Febbraro, M.; Pain, S. D.; Baugher, T.; Cizewski, J. A.; Ratkiewicz, A.; Toomey, B.

    2016-09-01

    The structure of nuclei provides insight into astrophysical reaction rates that are difficult to measure directly. These studies are often performed with transfer reaction and beta-decay measurements. These experiments benefit from particle-gamma coincident measurements providing information beyond that of particle detection alone. The Hybrid Array of Gamma Ray Detectors (HAGRiD) of LaBr3(Ce) scintillators has been designed with this purpose in mind. The design of the array permits it to be coupled with particle detector systems, such as the Oak Ridge Rutgers University Barrel Array (ORRUBA) of silicon detectors and the Versatile Array of Neutron Detectors at Low Energy (VANDLE). It is also designed to operate with the Jet Experiments in Nuclear Structure and Astrophysics (JENSA) advanced target system. HAGRiD's design avoids compromising the charged-particle angular resolution due to compact geometries often used to increase the gamma efficiency in other systems. First experimental data with HAGRiD coupled to VANDLE as well as ORRUBA and JENSA will be presented. This work is supported in part by the U.S. Department of Energy, Office of Science Nuclear Physics and the National Science Foundation.

  7. Pixel-feature hybrid fusion for PET/CT images.

    PubMed

    Zhu, Yang-Ming; Nortmann, Charles A

    2011-02-01

    Color blending is a popular display method for functional and anatomic image fusion. The underlay image is typically displayed in grayscale, and the overlay image is displayed in pseudo colors. This pixel-level fusion provides too much information for reviewers to analyze quickly and effectively and clutters the display. To improve the fusion image reviewing speed and reduce the information clutter, a pixel-feature hybrid fusion method is proposed and tested for PET/CT images. Segments of the colormap are selectively masked to have a few discrete colors, and pixels displayed in the masked colors are made transparent. The colormap thus creates a false contouring effect on overlay images and allows the underlay to show through to give contours an anatomic context. The PET standardized uptake value (SUV) is used to control where colormap segments are masked. Examples show that SUV features can be extracted and blended with CT image instantaneously for viewing and diagnosis, and the non-feature part of the PET image is transparent. The proposed pixel-feature hybrid fusion highlights PET SUV features on CT images and reduces display clutters. It is easy to implement and can be used as complementarily to existing pixel-level fusion methods.

  8. Single electron tunneling in large scale nanojunction arrays with bisferrocene-nanoparticle hybrids

    NASA Astrophysics Data System (ADS)

    Karmakar, Shilpi; Kumar, Susmit; Marzo, Pasquale; Primiceri, Elisabetta; di Corato, Riccardo; Rinaldi, Ross; Cozzi, Pier Giorgio; Bramanti, Alessandro Paolo; Maruccio, Giuseppe

    2012-03-01

    We report on the fabrication and single electron tunneling behaviour of large scale arrays of nanogap electrodes bridged by bisferrocene-gold nanoparticle hybrids (BFc-AuNP). Coulomb staircase was observed in the low temperature current-voltage curves measured on the junctions with asymmetric tunnel barriers. On the other hand, junctions with symmetric tunneling barrier exhibited mere nonlinear current voltage characteristics without discrete staircase. The experimental results agreed well with simulations based on the orthodox theory. The junction resistance showed thermally activated conduction behaviour at higher temperature. The overall voltage and temperature dependent results show that the transport behaviour of the large arrays of single particle devices obtained by a facile optical lithography and chemical etching process corresponds with the behaviour of single particle devices fabricated by other techniques like e-beam lithography and mechanical breaking methods.We report on the fabrication and single electron tunneling behaviour of large scale arrays of nanogap electrodes bridged by bisferrocene-gold nanoparticle hybrids (BFc-AuNP). Coulomb staircase was observed in the low temperature current-voltage curves measured on the junctions with asymmetric tunnel barriers. On the other hand, junctions with symmetric tunneling barrier exhibited mere nonlinear current voltage characteristics without discrete staircase. The experimental results agreed well with simulations based on the orthodox theory. The junction resistance showed thermally activated conduction behaviour at higher temperature. The overall voltage and temperature dependent results show that the transport behaviour of the large arrays of single particle devices obtained by a facile optical lithography and chemical etching process corresponds with the behaviour of single particle devices fabricated by other techniques like e-beam lithography and mechanical breaking methods. Electronic supplementary

  9. Development of wide-band X-ray/gamma-ray imagers using reach through APD arrays

    SciTech Connect

    Nakamori, T.; Kataoka, J.; Toizumi, T.; Koizumi, M.; Tanaka, S.; Kanai, Y.; Yatsu, Y.; Kawai, N.; Ishikawa, Y.; Kawai, T.; Kawabata, N.; Matsunaga, Y.

    2009-05-25

    It is quite important to obtain wide band spectra of gamma-ray bursts (GRBs) at the same time in order to probe the emission processes or the structure of GRBs. An avalanche photo diode (APD) is a compact photon sensor with an internal gain of 100. We have developed an X-ray/gamma-ray detector using a back-illuminated reach-through APD (5x5 mm{sup 2}) optically coupled with a conventional CsI(Tl) scintillator, which covers typically from 1 keV to 1 MeV. Further, we developed a 1-dimensional array of the 8/16 APDs (net 16x20 mm{sup 2}) for the purpose of an imaging photon detector to be used in future GRB missions. Here we present the current status and performance of our hybrid detector.

  10. 1p36 deletion syndrome confirmed by fluorescence in situ hybridization and array-comparative genomic hybridization analysis

    PubMed Central

    Kang, Dong Soo; Shin, Eunsim

    2016-01-01

    Pediatric epilepsy can be caused by various conditions, including specific syndromes. 1p36 deletion syndrome is reported in 1 in 5,000–10,000 newborns, and its characteristic clinical features include developmental delay, mental retardation, hypotonia, congenital heart defects, seizure, and facial dysmorphism. However, detection of the terminal deletion in chromosome 1p by conventional G-banded karyotyping is difficult. Here we present a case of epilepsy with profound developmental delay and characteristic phenotypes. A 7-year- and 6-month-old boy experienced afebrile generalized seizure at the age of 5 years and 3 months. He had recurrent febrile seizures since 12 months of age and showed severe global developmental delay, remarkable hypotonia, short stature, and dysmorphic features such as microcephaly; small, low-set ears; dark, straight eyebrows; deep-set eyes; flat nasal bridge; midface hypoplasia; and a small, pointed chin. Previous diagnostic work-up, including conventional chromosomal analysis, revealed no definite causes. However, array-comparative genomic hybridization analysis revealed 1p36 deletion syndrome with a 9.15-Mb copy loss of the 1p36.33-1p36.22 region, and fluorescence in situ hybridization analysis (FISH) confirmed this diagnosis. This case highlights the need to consider detailed chromosomal study for patients with delayed development and epilepsy. Furthermore, 1p36 deletion syndrome should be considered for patients presenting seizure and moderate-to-severe developmental delay, particularly if the patient exhibits dysmorphic features, short stature, and hypotonia. PMID:28018437

  11. 1p36 deletion syndrome confirmed by fluorescence in situ hybridization and array-comparative genomic hybridization analysis.

    PubMed

    Kang, Dong Soo; Shin, Eunsim; Yu, Jeesuk

    2016-11-01

    Pediatric epilepsy can be caused by various conditions, including specific syndromes. 1p36 deletion syndrome is reported in 1 in 5,000-10,000 newborns, and its characteristic clinical features include developmental delay, mental retardation, hypotonia, congenital heart defects, seizure, and facial dysmorphism. However, detection of the terminal deletion in chromosome 1p by conventional G-banded karyotyping is difficult. Here we present a case of epilepsy with profound developmental delay and characteristic phenotypes. A 7-year- and 6-month-old boy experienced afebrile generalized seizure at the age of 5 years and 3 months. He had recurrent febrile seizures since 12 months of age and showed severe global developmental delay, remarkable hypotonia, short stature, and dysmorphic features such as microcephaly; small, low-set ears; dark, straight eyebrows; deep-set eyes; flat nasal bridge; midface hypoplasia; and a small, pointed chin. Previous diagnostic work-up, including conventional chromosomal analysis, revealed no definite causes. However, array-comparative genomic hybridization analysis revealed 1p36 deletion syndrome with a 9.15-Mb copy loss of the 1p36.33-1p36.22 region, and fluorescence in situ hybridization analysis (FISH) confirmed this diagnosis. This case highlights the need to consider detailed chromosomal study for patients with delayed development and epilepsy. Furthermore, 1p36 deletion syndrome should be considered for patients presenting seizure and moderate-to-severe developmental delay, particularly if the patient exhibits dysmorphic features, short stature, and hypotonia.

  12. Ultrasonic Imaging Using a Flexible Array: Improvements to the Maximum Contrast Autofocus Algorithm

    NASA Astrophysics Data System (ADS)

    Hunter, A. J.; Drinkwater, B. W.; Wilcox, P. D.

    2009-03-01

    In previous work, we have presented the maximum contrast autofocus algorithm for estimating unknown imaging parameters, e.g., for imaging through complicated surfaces using a flexible ultrasonic array. This paper details recent improvements to the algorithm. The algorithm operates by maximizing the image contrast metric with respect to the imaging parameters. For a flexible array, the relative positions of the array elements are parameterized using a cubic spline function and the spline control points are estimated by iterative maximisation of the image contrast via simulated annealing. The resultant spline gives an estimate of the array geometry and the profile of the surface that it has conformed to, allowing the generation of a well-focused image. A pre-processing step is introduced to obtain an initial estimate of the array geometry, reducing the time taken for the algorithm to convergence. Experimental results are demonstrated using a flexible array prototype.

  13. ULTRASONIC IMAGING USING A FLEXIBLE ARRAY: IMPROVEMENTS TO THE MAXIMUM CONTRAST AUTOFOCUS ALGORITHM

    SciTech Connect

    Hunter, A. J.; Drinkwater, B. W.; Wilcox, P. D.

    2009-03-03

    In previous work, we have presented the maximum contrast autofocus algorithm for estimating unknown imaging parameters, e.g., for imaging through complicated surfaces using a flexible ultrasonic array. This paper details recent improvements to the algorithm. The algorithm operates by maximizing the image contrast metric with respect to the imaging parameters. For a flexible array, the relative positions of the array elements are parameterized using a cubic spline function and the spline control points are estimated by iterative maximisation of the image contrast via simulated annealing. The resultant spline gives an estimate of the array geometry and the profile of the surface that it has conformed to, allowing the generation of a well-focused image. A pre-processing step is introduced to obtain an initial estimate of the array geometry, reducing the time taken for the algorithm to convergence. Experimental results are demonstrated using a flexible array prototype.

  14. Design and numerical evaluation of a volume coil array for parallel MR imaging at ultrahigh fields

    PubMed Central

    Pang, Yong; Wong, Ernest W.H.; Yu, Baiying

    2014-01-01

    In this work, we propose and investigate a volume coil array design method using different types of birdcage coils for MR imaging. Unlike the conventional radiofrequency (RF) coil arrays of which the array elements are surface coils, the proposed volume coil array consists of a set of independent volume coils including a conventional birdcage coil, a transverse birdcage coil, and a helix birdcage coil. The magnetic fluxes of these three birdcage coils are intrinsically cancelled, yielding a highly decoupled volume coil array. In contrast to conventional non-array type volume coils, the volume coil array would be beneficial in improving MR signal-to-noise ratio (SNR) and also gain the capability of implementing parallel imaging. The volume coil array is evaluated at the ultrahigh field of 7T using FDTD numerical simulations, and the g-factor map at different acceleration rates was also calculated to investigate its parallel imaging performance. PMID:24649435

  15. Hybrid coded aperture and Compton imaging using an active mask

    NASA Astrophysics Data System (ADS)

    Schultz, L. J.; Wallace, M. S.; Galassi, M. C.; Hoover, A. S.; Mocko, M.; Palmer, D. M.; Tornga, S. R.; Kippen, R. M.; Hynes, M. V.; Toolin, M. J.; Harris, B.; McElroy, J. E.; Wakeford, D.; Lanza, R. C.; Horn, B. K. P.; Wehe, D. K.

    2009-09-01

    The trimodal imager (TMI) images gamma-ray sources from a mobile platform using both coded aperture (CA) and Compton imaging (CI) modalities. In this paper we will discuss development and performance of image reconstruction algorithms for the TMI. In order to develop algorithms in parallel with detector hardware we are using a GEANT4 [J. Allison, K. Amako, J. Apostolakis, H. Araujo, P.A. Dubois, M. Asai, G. Barrand, R. Capra, S. Chauvie, R. Chytracek, G. Cirrone, G. Cooperman, G. Cosmo, G. Cuttone, G. Daquino, et al., IEEE Trans. Nucl. Sci. NS-53 (1) (2006) 270] based simulation package to produce realistic data sets for code development. The simulation code incorporates detailed detector modeling, contributions from natural background radiation, and validation of simulation results against measured data. Maximum likelihood algorithms for both imaging methods are discussed, as well as a hybrid imaging algorithm wherein CA and CI information is fused to generate a higher fidelity reconstruction.

  16. Development of horn antenna mixer array with internal local oscillator module for microwave imaging diagnostics.

    PubMed

    Kuwahara, D; Ito, N; Nagayama, Y; Yoshinaga, T; Yamaguchi, S; Yoshikawa, M; Kohagura, J; Sugito, S; Kogi, Y; Mase, A

    2014-11-01

    A new antenna array is proposed in order to improve the sensitivity and complexity of microwave imaging diagnostics systems such as a microwave imaging reflectometry, a microwave imaging interferometer, and an electron cyclotron emission imaging. The antenna array consists of five elements: a horn antenna, a waveguide-to-microstrip line transition, a mixer, a local oscillation (LO) module, and an intermediate frequency amplifier. By using an LO module, the LO optics can be removed, and the supplied LO power to each element can be equalized. We report details of the antenna array and characteristics of a prototype antenna array.

  17. Development of horn antenna mixer array with internal local oscillator module for microwave imaging diagnostics

    NASA Astrophysics Data System (ADS)

    Kuwahara, D.; Ito, N.; Nagayama, Y.; Yoshinaga, T.; Yamaguchi, S.; Yoshikawa, M.; Kohagura, J.; Sugito, S.; Kogi, Y.; Mase, A.

    2014-11-01

    A new antenna array is proposed in order to improve the sensitivity and complexity of microwave imaging diagnostics systems such as a microwave imaging reflectometry, a microwave imaging interferometer, and an electron cyclotron emission imaging. The antenna array consists of five elements: a horn antenna, a waveguide-to-microstrip line transition, a mixer, a local oscillation (LO) module, and an intermediate frequency amplifier. By using an LO module, the LO optics can be removed, and the supplied LO power to each element can be equalized. We report details of the antenna array and characteristics of a prototype antenna array.

  18. Multichannel Double-Row Transmission Line Array for Human MR Imaging at Ultrahigh Fields

    PubMed Central

    Yan, Xinqiang; Pedersen, Jan Ole; Wei, Long

    2017-01-01

    Objective In microstrip transmission line (MTL) transmit/receive (transceive) arrays used for ultrahigh field MRI, the array length is often constrained by the required resonant frequency, limiting the image coverage. The purpose of this study is to increase the imaging coverage and also improve its parallel imaging capability by utilizing a double-row design. Methods A 16-channel double-row MTL transceive array was designed, constructed, and tested for human head imaging at 7 T. Array elements between two rows were decoupled by using the induced current elimination or magnetic wall decoupling technique. In vivo human head images were acquired, and g-factor results were calculated to evaluate the performance of this double-row array. Results Testing results showed that all coil elements were well decoupled with a better than −18 dB transmission coefficient between any two elements. The double-row array improves the imaging quality of the lower portion of the human head, and has low g-factors even at high acceleration rates. Conclusion Compared with a regular single-row MTL array, the double-row array demonstrated a larger imaging coverage along the z-direction with improved parallel imaging capability. Significance The proposed technique is particularly suitable for the design of large-sized transceive arrays with large channel counts, which ultimately benefits the imaging performance in human MRI. PMID:25706499

  19. Development of horn antenna mixer array with internal local oscillator module for microwave imaging diagnostics

    SciTech Connect

    Kuwahara, D.; Ito, N.; Nagayama, Y.; Yoshinaga, T.; Yamaguchi, S.; Yoshikawa, M.; Kohagura, J.; Sugito, S.; Kogi, Y.; Mase, A.

    2014-11-15

    A new antenna array is proposed in order to improve the sensitivity and complexity of microwave imaging diagnostics systems such as a microwave imaging reflectometry, a microwave imaging interferometer, and an electron cyclotron emission imaging. The antenna array consists of five elements: a horn antenna, a waveguide-to-microstrip line transition, a mixer, a local oscillation (LO) module, and an intermediate frequency amplifier. By using an LO module, the LO optics can be removed, and the supplied LO power to each element can be equalized. We report details of the antenna array and characteristics of a prototype antenna array.

  20. Hybrid lidar radar receiver for underwater imaging applications

    NASA Astrophysics Data System (ADS)

    Seetamraju, Madhavi; Gurjar, Rajan; Squillante, Michael; Derderian, Jeffrey P.

    2009-05-01

    In this work, we present research performed to improve the receiver characteristics for underwater imaging applications using the hybrid lidar-radar detection technique. We report the development of the next-generation coherent heterodyne receiver using modulation of the optical receiver's amplifier gain. Significant advantages in the receiver specifications are achieved using a large-area, high gain, low-noise silicon avalanche photodiode (APD) as the photodetector cum frequency mixer-demodulator. We demonstrate that heterodyne detection by gain modulation of APD can be used to increase the signal-to-noise ratio, detection sensitivity and bandwidth for the hybrid receiver system.

  1. Marketing image categorization using hybrid human-machine combinations

    NASA Astrophysics Data System (ADS)

    Gnanasambandam, Nathan; Madhu, Himanshu

    2012-03-01

    Marketing instruments with nested, short-form, symbol loaded content need to be studied differently. Image classification in the Web2.0 world can dynamically use a configurable amount of internal and external data as well as varying levels of crowd-sourcing. Our work is one such examination of how to construct a hybrid technique involving learning and crowd-sourcing. Through a parameter called turkmix and a multitude of crowd-sourcing techniques available we show that we can control the trend of metrics such as precision and recall on the hybrid categorizer.

  2. Hyperspectral image super-resolution: a hybrid color mapping approach

    NASA Astrophysics Data System (ADS)

    Zhou, Jin; Kwan, Chiman; Budavari, Bence

    2016-07-01

    NASA has been planning a hyperspectral infrared imager mission which will provide global coverage using a hyperspectral imager with 60-m resolution. In some practical applications, such as special crop monitoring or mineral mapping, 60-m resolution may still be too coarse. There have been many pansharpening algorithms for hyperspectral images by fusing high-resolution (HR) panchromatic or multispectral images with low-resolution (LR) hyperspectral images. We propose an approach to generating HR hyperspectral images by fusing high spatial resolution color images with low spatial resolution hyperspectral images. The idea is called hybrid color mapping (HCM) and involves a mapping between a high spatial resolution color image and a low spatial resolution hyperspectral image. Several variants of the color mapping idea, including global, local, and hybrid, are proposed and investigated. It was found that the local HCM yielded the best performance. Comparison of the local HCM with >10 state-of-the-art algorithms using five performance metrics has been carried out using actual images from the air force and NASA. Although our HCM method does not require a point spread function (PSF), our results are comparable to or better than those methods that do require PSF. More importantly, our performance is better than most if not all methods that do not require PSF. After applying our HCM algorithm, not only the visual performance of the hyperspectral image has been significantly improved, but the target classification performance has also been improved. Another advantage of our technique is that it is very efficient and can be easily parallelized. Hence, our algorithm is very suitable for real-time applications.

  3. Imaging Prostate Cancer Microenvironment by collagen Hybridization

    DTIC Science & Technology

    2014-10-01

    from enlarged lymph nodes. Figure 3. Ex vivo NIRF imaging of PC-3 PIP xenograft. AI = androgen independent, AR = androgen receptor negative, PSMA ...center O.D. rim/focal ROI PC-3 rapid 0.25 ± .09 1.21 ± 0.40 PC-3 ( PSMA +) PIP rapid 0.26 ± .12 NA DU-145 slow 0.01 ± 0.01 0.06 ± 0.02 HP LNCaP

  4. Imaging Prostate Cancer Microenvironment by Collagen Hybridization

    DTIC Science & Technology

    2013-10-01

    microdialysis cassette against PBS, pH 7.5 for 1 hour. Radio TLC was used to assess radiochemical purity before and after a test-decaging. The presence of... TLC and in vivo imaging results. Radio TLC in bottom left shows multiple labeled species following photodeprotection in the presence and absence of...portion of both DTPA and DOTA-chelated radioindium complex, which is also suggested by the radio TLC data. 7    Labeling with radioiodine, however

  5. Matrix phased array (MPA) imaging technology for resistance spot welds

    SciTech Connect

    Na, Jeong K.; Gleeson, Sean T.

    2014-02-18

    A three-dimensional MPA probe has been incorporated with a high speed phased array electronic board to visualize nugget images of resistance spot welds. The primary application area of this battery operated portable MPA ultrasonic imaging system is in the automotive industry which a conventional destructive testing process is commonly adopted to check the quality of resistance spot welds in auto bodies. Considering an average of five-thousand spot welds in a medium size passenger vehicle, the amount of time and effort given to popping the welds and measuring nugget size are immeasurable in addition to the millions of dollars' worth of scrap metals recycled per plant per year. This wasteful labor intensive destructive testing process has become less reliable as auto body sheet metal has transitioned from thick and heavy mild steels to thin and light high strength steels. Consequently, the necessity of developing a non-destructive inspection methodology has become inevitable. In this paper, the fundamental aspects of the current 3-D probe design, data acquisition algorithms, and weld nugget imaging process are discussed.

  6. Matrix phased array (MPA) imaging technology for resistance spot welds

    NASA Astrophysics Data System (ADS)

    Na, Jeong K.; Gleeson, Sean T.

    2014-02-01

    A three-dimensional MPA probe has been incorporated with a high speed phased array electronic board to visualize nugget images of resistance spot welds. The primary application area of this battery operated portable MPA ultrasonic imaging system is in the automotive industry which a conventional destructive testing process is commonly adopted to check the quality of resistance spot welds in auto bodies. Considering an average of five-thousand spot welds in a medium size passenger vehicle, the amount of time and effort given to popping the welds and measuring nugget size are immeasurable in addition to the millions of dollars' worth of scrap metals recycled per plant per year. This wasteful labor intensive destructive testing process has become less reliable as auto body sheet metal has transitioned from thick and heavy mild steels to thin and light high strength steels. Consequently, the necessity of developing a non-destructive inspection methodology has become inevitable. In this paper, the fundamental aspects of the current 3-D probe design, data acquisition algorithms, and weld nugget imaging process are discussed.

  7. ISGRI: a CdTe array imager for INTEGRAL

    NASA Astrophysics Data System (ADS)

    Lebrun, Francois; Blondel, Claire; Fondeur, Irene; Goldwurm, Andrea; Laurent, Phillipe; Leray, Jean P.

    1996-10-01

    The INTEGRAL soft gamma-ray imager (ISGRI) is a large and thin CdTe array. Operating at room temperature, this gamma camera covers the lower part (below 200 keV) of the energy domain (20 keV - 10 MeV) of the imager on board the INTEGRAL Satellite (IBIS). The ASIC's front-end electronics features particularly a low noise preamplifier, allowing a threshold below 20 keV and a pulse rise-time measurement which permits a charge loss correction. The charge loss correction and its performances are presented as well as the results of various studies on CdTe thermal behavior and radiation hardness. At higher energy (above 200 keV) ISGRI will operate in conjunction with PICsIT, the IBIS CsI gamma camera. A selection among the events in coincidence performed on the basis of the Compton scattering properties reduces strongly the background. This allows an improvement of the sensitivity and permits short term imaging and spectral studies (high energy pulsars) which otherwise would not have fit within the IBIS telemetry allocation.

  8. Arrays of Nano Tunnel Junctions as Infrared Image Sensors

    NASA Technical Reports Server (NTRS)

    Son, Kyung-Ah; Moon, Jeong S.; Prokopuk, Nicholas

    2006-01-01

    Infrared image sensors based on high density rectangular planar arrays of nano tunnel junctions have been proposed. These sensors would differ fundamentally from prior infrared sensors based, variously, on bolometry or conventional semiconductor photodetection. Infrared image sensors based on conventional semiconductor photodetection must typically be cooled to cryogenic temperatures to reduce noise to acceptably low levels. Some bolometer-type infrared sensors can be operated at room temperature, but they exhibit low detectivities and long response times, which limit their utility. The proposed infrared image sensors could be operated at room temperature without incurring excessive noise, and would exhibit high detectivities and short response times. Other advantages would include low power demand, high resolution, and tailorability of spectral response. Neither bolometers nor conventional semiconductor photodetectors, the basic detector units as proposed would partly resemble rectennas. Nanometer-scale tunnel junctions would be created by crossing of nanowires with quantum-mechanical-barrier layers in the form of thin layers of electrically insulating material between them (see figure). A microscopic dipole antenna sized and shaped to respond maximally in the infrared wavelength range that one seeks to detect would be formed integrally with the nanowires at each junction. An incident signal in that wavelength range would become coupled into the antenna and, through the antenna, to the junction. At the junction, the flow of electrons between the crossing wires would be dominated by quantum-mechanical tunneling rather than thermionic emission. Relative to thermionic emission, quantum mechanical tunneling is a fast process.

  9. Application of sparse array and MIMO in near-range microwave imaging

    NASA Astrophysics Data System (ADS)

    Qi, Yaolong; Wang, Yanping; Tan, Weixian; Hong, Wen

    2011-11-01

    Near range microwave imaging systems have broad application prospects in the field of concealed weapon detection, biomedical imaging, nondestructive testing, etc. In this paper, the techniques of MIMO and sparse line array are applied to near range microwave imaging, which can greatly reduce the complexity of imaging systems. In detail, the paper establishes two-dimensional near range MIMO imaging geometry and corresponding echo model, where the imaging geometry is formed by arranging sparse antenna array in azimuth direction and transmitting broadband signals in range direction; then, by analyzing the relationship between MIMO and convolution principle, the paper develops a method of arranging sparse line array which can be equivalent to a full array; and the paper deduces the backprojection algorithm applied to near ranging MIMO imaging geometry; finally, the imaging geometry and corresponding imaging algorithm proposed in this paper are investigated and verified by means of theoretical analysis and numerical simulations.

  10. Chromatic visualization of reflectivity variance within hybridized directional OCT images

    NASA Astrophysics Data System (ADS)

    Makhijani, Vikram S.; Roorda, Austin; Bayabo, Jan Kristine; Tong, Kevin K.; Rivera-Carpio, Carlos A.; Lujan, Brandon J.

    2013-03-01

    This study presents a new method of visualizing hybridized images of retinal spectral domain optical coherence tomography (SDOCT) data comprised of varied directional reflectivity. Due to the varying reflectivity of certain retinal structures relative to angle of incident light, SDOCT images obtained with differing entry positions result in nonequivalent images of corresponding cellular and extracellular structures, especially within layers containing photoreceptor components. Harnessing this property, cross-sectional pathologic and non-pathologic macular images were obtained from multiple pupil entry positions using commercially-available OCT systems, and custom segmentation, alignment, and hybridization algorithms were developed to chromatically visualize the composite variance of reflectivity effects. In these images, strong relative reflectivity from any given direction visualizes as relative intensity of its corresponding color channel. Evident in non-pathologic images was marked enhancement of Henle's fiber layer (HFL) visualization and varying reflectivity patterns of the inner limiting membrane (ILM) and photoreceptor inner/outer segment junctions (IS/OS). Pathologic images displayed similar and additional patterns. Such visualization may allow a more intuitive understanding of structural and physiologic processes in retinal pathologies.

  11. Multiplex detection of disease marker proteins with arrayed imaging reflectometry

    NASA Astrophysics Data System (ADS)

    Yadav, Amrita; Sriram, Rashmi; Miller, Benjamin L.

    2010-02-01

    Arrayed Imaging Reflectometry, or "AIR", is a new label-free optical technique for detecting proteins. AIR relies on binding-induced changes in the response of an antireflective coating on the surface of a silicon chip. Thus far, we have demonstrated the use of AIR for the detection of pathogenic E. coli, and for multiplex detection of a broad range of proteins in human serum. Creation of the near-perfect antireflective coating on the surface of silicon requires careful control over preparation of the chip surface prior to probe molecule immobilization. We present methods for highly reproducible, solution-phase silanization and glutaraldehyde functionalization of silicon chips carrying a layer of thermal oxide. Following functionalization with antibodies and passivation of remaining reactive groups, these surfaces provide exceptional performance in the AIR assay.

  12. Tunable elastomer-based virtually imaged phased array.

    PubMed

    Metz, Philipp; Block, Hendrik; Behnke, Christopher; Krantz, Matthias; Gerken, Martina; Adam, Jost

    2013-02-11

    Virtually imaged phased arrays (VIPAs) offer a high potential for wafer-level integration and superior optical properties compared to conventional gratings. We introduce an elastomer-based tunable VIPA enabling fine tuning of the dispersion characteristics. It consists of a poly-dimethylsiloxane (PDMS) layer sandwiched between silver bottom and top coatings, which form the VIPA's high reflective and semi-transparent mirror, respectively. The latter also acts as an electrode for Joule heating, such that the optical PDMS resonator cavity tuning is carried out via a combination of thermal expansion and the thermo-optic effect. Analogous to the free spectral range (FSR), based on a VIPA specific dispersion law, we introduce a new characteristic VIPA performance measure, namely the free angular range (FAR). We report a tuning span of one FAR achieved by a 7.2K temperature increase of a 170μm PDMS VIPA. Both resonance quality and tunability are analyzed in numerical simulations and experiments.

  13. Photon-Counting Arrays for Time-Resolved Imaging

    PubMed Central

    Antolovic, I. Michel; Burri, Samuel; Hoebe, Ron A.; Maruyama, Yuki; Bruschini, Claudio; Charbon, Edoardo

    2016-01-01

    The paper presents a camera comprising 512 × 128 pixels capable of single-photon detection and gating with a maximum frame rate of 156 kfps. The photon capture is performed through a gated single-photon avalanche diode that generates a digital pulse upon photon detection and through a digital one-bit counter. Gray levels are obtained through multiple counting and accumulation, while time-resolved imaging is achieved through a 4-ns gating window controlled with subnanosecond accuracy by a field-programmable gate array. The sensor, which is equipped with microlenses to enhance its effective fill factor, was electro-optically characterized in terms of sensitivity and uniformity. Several examples of capture of fast events are shown to demonstrate the suitability of the approach. PMID:27367697

  14. Least-Squares Self-Calibration of Imaging Array Data

    NASA Technical Reports Server (NTRS)

    Arendt, R. G.; Moseley, S. H.; Fixsen, D. J.

    2004-01-01

    When arrays are used to collect multiple appropriately-dithered images of the same region of sky, the resulting data set can be calibrated using a least-squares minimization procedure that determines the optimal fit between the data and a model of that data. The model parameters include the desired sky intensities as well as instrument parameters such as pixel-to-pixel gains and offsets. The least-squares solution simultaneously provides the formal error estimates for the model parameters. With a suitable observing strategy, the need for separate calibration observations is reduced or eliminated. We show examples of this calibration technique applied to HST NICMOS observations of the Hubble Deep Fields and simulated SIRTF IRAC observations.

  15. Ultrafast dynamics of metal plasmons induced by 2D semiconductor excitons in hybrid nanostructure arrays

    SciTech Connect

    Boulesbaa, Abdelaziz; Babicheva, Viktoriia E.; Wang, Kai; Kravchenko, Ivan I.; Lin, Ming -Wei; Mahjouri-Samani, Masoud; Jacobs, Christopher B.; Puretzky, Alexander A.; Xiao, Kai; Ivanov, Ilia N.; Rouleau, Christopher M.; Geohegan, David B.

    2016-11-17

    With the advanced progress achieved in the field of nanotechnology, localized surface plasmons resonances (LSPRs) are actively considered to improve the efficiency of metal-based photocatalysis, photodetection, and photovoltaics. Here, we report on the exchange of energy and electric charges in a hybrid composed of a two-dimensional tungsten disulfide (2D-WS2) monolayer and an array of aluminum (Al) nanodisks. Femtosecond pump-probe spectroscopy results indicate that within ~830 fs after photoexcitation of the 2D-WS2 semiconductor, energy transfer from the 2D-WS2 excitons excites the plasmons of the Al array. Then, upon the radiative and/or nonradiative damping of these excited plasmons, energy and/or electron transfer back to the 2D-WS2 semiconductor takes place as indicated by an increase in the reflected probe at the 2D exciton transition energies at later time-delays. This simultaneous exchange of energy and charges between the metal and the 2D-WS2 semiconductor resulted in an extension of the average lifetime of the 2D-excitons from ~15 to ~58 ps in absence and presence of the Al array, respectively. Furthermore, the indirectly excited plasmons were found to live as long as the 2D-WS2 excitons exist. Furthermore, the demonstrated ability to generate exciton-plasmons coupling in a hybrid nanostructure may open new opportunities for optoelectronic applications such as plasmonic-based photodetection and photocatalysis.

  16. Statistical methods for detecting genomic alterations through array-based comparative genomic hybridization (CGH).

    PubMed

    Wang, Yuedong; Guo, Sun-Wei

    2004-01-01

    Array-based comparative genomic hybridization (ABCGH) is an emerging high-resolution and high-throughput molecular genetic technique that allows genome-wide screening for chromosome alterations associated with tumorigenesis. Like the cDNA microarrays, ABCGH uses two differentially labeled test and reference DNAs which are cohybridized to cloned genomic fragments immobilized on glass slides. The hybridized DNAs are then detected in two different fluorochromes, and the significant deviation from unity in the ratios of the digitized intensity values is indicative of copy-number differences between the test and reference genomes. Proper statistical analyses need to account for many sources of variation besides genuine differences between the two genomes. In particular, spatial correlations, the variable nature of the ratio variance and non-Normal distribution call for careful statistical modeling. We propose two new statistics, the standard t-statistic and its modification with variances smoothed along the genome, and two tests for each statistic, the standard t-test and a test based on the hybrid adaptive spline (HAS). Simulations indicate that the smoothed t-statistic always improves the performance over the standard t-statistic. The t-tests are more powerful in detecting isolated alterations while those based on HAS are more powerful in detecting a cluster of alterations. We apply the proposed methods to the identification of genomic alterations in endometrium in women with endometriosis.

  17. Machine learning models for lung cancer classification using array comparative genomic hybridization.

    PubMed

    Aliferis, C F; Hardin, D; Massion, P P

    2002-01-01

    Array CGH is a recently introduced technology that measures changes in the gene copy number of hundreds of genes in a single experiment. The primary goal of this study was to develop machine learning models that classify non-small Lung Cancers according to histopathology types and to compare several machine learning methods in this learning task. DNA from tumors of 37 patients (21 squamous carcinomas, and 16 adenocarcinomas) were extracted and hybridized onto a 452 BAC clone array. The following algorithms were used: KNN, Decision Tree Induction, Support Vector Machines and Feed-Forward Neural Networks. Performance was measured via leave-one-out classification accuracy. The best multi-gene model found had a leave-one-out accuracy of 89.2%. Decision Trees performed poorer than the other methods in this learning task and dataset. We conclude that gene copy numbers as measured by array CGH are, collectively, an excellent indicator of histological subtype. Several interesting research directions are discussed.

  18. Fabrication of hybrid nanostructured arrays using a PDMS/PDMS replication process.

    PubMed

    Hassanin, H; Mohammadkhani, A; Jiang, K

    2012-10-21

    In the study, a novel and low cost nanofabrication process is proposed for producing hybrid polydimethylsiloxane (PDMS) nanostructured arrays. The proposed process involves monolayer self-assembly of polystyrene (PS) spheres, PDMS nanoreplication, thin film coating, and PDMS to PDMS (PDMS/PDMS) replication. A self-assembled monolayer of PS spheres is used as the first template. Second, a PDMS template is achieved by replica moulding. Third, the PDMS template is coated with a platinum or gold layer. Finally, a PDMS nanostructured array is developed by casting PDMS slurry on top of the coated PDMS. The cured PDMS is peeled off and used as a replica surface. In this study, the influences of the coating on the PDMS topography, contact angle of the PDMS slurry and the peeling off ability are discussed in detail. From experimental evaluation, a thickness of at least 20 nm gold layer or 40 nm platinum layer on the surface of the PDMS template improves the contact angle and eases peeling off. The coated PDMS surface is successfully used as a template to achieve the replica with a uniform array via PDMS/PDMS replication process. Both the PDMS template and the replica are free of defects and also undistorted after demoulding with a highly ordered hexagonal arrangement. In addition, the geometry of the nanostructured PDMS can be controlled by changing the thickness of the deposited layer. The simplicity and the controllability of the process show great promise as a robust nanoreplication method for functional applications.

  19. Hybrid triple-level-cell/multi-level-cell NAND flash storage array with chip exchangeable method

    NASA Astrophysics Data System (ADS)

    Hachiya, Shogo; Johguchi, Koh; Miyaji, Kousuke; Takeuchi, Ken

    2014-01-01

    This paper proposes a mix-and-match design method for triple level cell (TLC)/multi level cell (MLC) NAND flash hybrid and exchangeable storage arrays. A TLC-NAND flash provides an low cost and high capacity memory solution. However the reliability and access latency of TLC NAND flash are degraded from MLC NAND flash. Additionally, the block unit write is preferable for TLC NAND flash since the write order is complicated due to narrow data margin and write disturbance. The proposed solution combines TLC and MLC NAND flash memories for a storage array. To reduce access to TLC NAND flash, the stored data is screened and only the static frozen data are stored into TLC NAND flash with a Round-Robin frozen data collection algorithm (RR-FDCA). Furthermore, the proposed chip exchanging method extends the solid-state drive (SSD) lifetime without system suspending. As a result, in spite of moderate characteristics of TLC NAND flash, the proposed storage array can achieve 29% write energy saving and 56% write performance enhancement with 17% cost reduction, compared with the conventional MLC-only SSD.

  20. Tilted microstrip phased arrays with improved electromagnetic decoupling for ultrahigh-field magnetic resonance imaging.

    PubMed

    Pang, Yong; Wu, Bing; Jiang, Xiaohua; Vigneron, Daniel B; Zhang, Xiaoliang

    2014-12-01

    One of the technical challenges in designing a dedicated transceiver radio frequency (RF) array for MR imaging in humans at ultrahigh magnetic fields is how to effectively decouple the resonant elements of the array. In this work, we propose a new approach using tilted microstrip array elements for improving the decoupling performance and potentially parallel imaging capability. To investigate and validate the proposed design technique, an 8-channel volume array with tilted straight-type microstrip elements was designed, capable for human imaging at the ultrahigh field of 7 Tesla. In this volume transceiver array, its electromagnetic decoupling behavior among resonant elements, RF field penetration to biological samples, and parallel imaging performance were studied through bench tests and in vivo MR imaging experiments. In this specific tilted element array design, decoupling among array elements changes with the tilted angle of the elements and the best decoupling can be achieved at certain tilted angle. In vivo human knee MR images were acquired using the tilted volume array at 7 Tesla for method validation. Results of this study demonstrated that the electromagnetic decoupling between array elements and the B1 field strength can be improved by using the tilted element method in microstrip RF coil array designs at the ultrahigh field of 7T.

  1. Hybrid Image Fusion for Sharpness Enhancement of Multi-Spectral Lunar Images

    NASA Astrophysics Data System (ADS)

    Awumah, Anna; Mahanti, Prasun; Robinson, Mark

    2016-10-01

    Image fusion enhances the sharpness of a multi-spectral (MS) image by incorporating spatial details from a higher-resolution panchromatic (Pan) image [1,2]. Known applications of image fusion for planetary images are rare, although image fusion is well-known for its applications to Earth-based remote sensing. In a recent work [3], six different image fusion algorithms were implemented and their performances were verified with images from the Lunar Reconnaissance Orbiter (LRO) Camera. The image fusion procedure obtained a high-resolution multi-spectral (HRMS) product from the LRO Narrow Angle Camera (used as Pan) and LRO Wide Angle Camera (used as MS) images. The results showed that the Intensity-Hue-Saturation (IHS) algorithm results in a high-spatial quality product while the Wavelet-based image fusion algorithm best preserves spectral quality among all the algorithms. In this work we show the results of a hybrid IHS-Wavelet image fusion algorithm when applied to LROC MS images. The hybrid method provides the best HRMS product - both in terms of spatial resolution and preservation of spectral details. Results from hybrid image fusion can enable new science and increase the science return from existing LROC images.[1] Pohl, Cle, and John L. Van Genderen. "Review article multisensor image fusion in remote sensing: concepts, methods and applications." International journal of remote sensing 19.5 (1998): 823-854.[2] Zhang, Yun. "Understanding image fusion." Photogramm. Eng. Remote Sens 70.6 (2004): 657-661.[3] Mahanti, Prasun et al. "Enhancement of spatial resolution of the LROC Wide Angle Camera images." Archives, XXIII ISPRS Congress Archives (2016).

  2. Compact hybrid real-time hyperspectral imaging system with high effective spatial, spectral, and temporal resolution

    NASA Astrophysics Data System (ADS)

    Roth, Filip; Abbadi, Ahmad; Herman, Ondrej; Pavelek, Martin; Prenosil, Vaclav

    2016-10-01

    Medical endoscopes for image-guided surgery commonly use standard color image sensors, discarding any more detailed spectral information. Medical spectroscopy devices with various spectral working ranges are specialized to specific medical procedures and in general are not usable for image-guided surgery due to limitations in spatial or temporal resolution. In this paper, we present an initial demonstrator of hyperspectral endoscope, composed of two image sensors with complementing parameters. Using this hybrid approach, combining sensors with different spatial and spectral resolutions and spectral ranges, we obtain improved coverage of all the respective parameters. After digitally processing and merging the video streams, while maintaining the better features of both, we obtain an imaging system providing high effective spatial, spectral, and temporal resolution. The system is based on field programmable gate arrays. It provides real-time video output (60 Hz), which is usable for navigation during image-guided surgery. The flexible system architecture allows for an easy extension of the processing algorithms and enables minimal video signal latency. Physical dimensions and portability of the system are comparable to standard off-the-shelf medical endoscope cameras. The device can output both processed video and standard visible light video signals on one or more video outputs of the system. The resulting processed video signal obtained from the combined image sensor data greatly increases the amount of useful information available to the end user.

  3. a Study Into the Effects of AN Austenitic Weld on Ultrasonic Array Imaging Performance

    NASA Astrophysics Data System (ADS)

    Hunter, A. J.; Drinkwater, B. W.; Zhang, J.; Wilcox, P. D.

    2011-06-01

    An industrial application of ultrasonic array imaging is the inspection of austenitic welds with high inhomogeneity and anisotropy. These result in attenuation and perturbation of the signals that adversely affects imaging performance. Here, the effects of perturbations introduced by an austenitic weld on array imaging performance are investigated experimentally. It is shown that three major factors contribute to the degradation of image quality: timing errors, phase errors, and multi-path propagation and scattering.

  4. Design, implementation and investigation of an image guide-based optical flip-flop array

    NASA Technical Reports Server (NTRS)

    Griffith, P. C.

    1987-01-01

    Presented is the design for an image guide-based optical flip-flop array created using a Hughes liquid crystal light valve and a flexible image guide in a feedback loop. This design is used to investigate the application of image guides as a communication mechanism in numerical optical computers. It is shown that image guides can be used successfully in this manner but mismatch match between the input and output fiber arrays is extremely limiting.

  5. Programmable hyperspectral image mapper with on-array processing

    NASA Technical Reports Server (NTRS)

    Cutts, James A. (Inventor)

    1995-01-01

    A hyperspectral imager includes a focal plane having an array of spaced image recording pixels receiving light from a scene moving relative to the focal plane in a longitudinal direction, the recording pixels being transportable at a controllable rate in the focal plane in the longitudinal direction, an electronic shutter for adjusting an exposure time of the focal plane, whereby recording pixels in an active area of the focal plane are removed therefrom and stored upon expiration of the exposure time, an electronic spectral filter for selecting a spectral band of light received by the focal plane from the scene during each exposure time and an electronic controller connected to the focal plane, to the electronic shutter and to the electronic spectral filter for controlling (1) the controllable rate at which the recording is transported in the longitudinal direction, (2) the exposure time, and (3) the spectral band so as to record a selected portion of the scene through M spectral bands with a respective exposure time t(sub q) for each respective spectral band q.

  6. Kinetics of Oligonucleotide Hybridization to DNA Probe Arrays on High-Capacity Porous Silica Substrates

    PubMed Central

    Glazer, Marc I.; Fidanza, Jacqueline A.; McGall, Glenn H.; Trulson, Mark O.; Forman, Jonathan E.; Frank, Curtis W.

    2007-01-01

    We have investigated the kinetics of DNA hybridization to oligonucleotide arrays on high-capacity porous silica films that were deposited by two techniques. Films created by spin coating pure colloidal silica suspensions onto a substrate had pores of ∼23 nm, relatively low porosity (35%), and a surface area of 17 times flat glass (for a 0.3-μm film). In the second method, latex particles were codeposited with the silica by spin coating and then pyrolyzed, which resulted in larger pores (36 nm), higher porosity (65%), and higher surface area (26 times flat glass for a 0.3-μm film). As a result of these favorable properties, the templated silica hybridized more quickly and reached a higher adsorbed target density (11 vs. 8 times flat glass at 22°C) than the pure silica. Adsorption of DNA onto the high-capacity films is controlled by traditional adsorption and desorption coefficients, as well as by morphology factors and transient binding interactions between the target and the probes. To describe these effects, we have developed a model based on the analogy to diffusion of a reactant in a porous catalyst. Adsorption values (ka, kd, and K) measured on planar arrays for the same probe/target system provide the parameters for the model and also provide an internally consistent comparison for the stability of the transient complexes. The interpretation of the model takes into account factors not previously considered for hybridization in three-dimensional films, including the potential effects of heterogeneous probe populations, partial probe/target complexes during diffusion, and non-1:1 binding structures. The transient complexes are much less stable than full duplexes (binding constants for full duplexes higher by three orders of magnitude or more), which may be a result of the unique probe density and distribution that is characteristic of the photolithographically patterned arrays. The behavior at 22°C is described well by the predictive equations for

  7. Short-Lag Spatial Coherence Imaging on Matrix Arrays, Part I: Beamforming Methods and Simulation Studies

    PubMed Central

    Hyun, Dongwoon; Trahey, Gregg E.; Jakovljevic, Marko; Dahl, Jeremy J.

    2014-01-01

    Short-lag spatial coherence (SLSC) imaging is a beamforming technique that has demonstrated improved imaging performance compared with conventional B-mode imaging in previous studies. Thus far, the use of 1-D arrays has limited coherence measurements and SLSC imaging to a single dimension. Here, the SLSC algorithm is extended for use on 2-D matrix array transducers and applied in a simulation study examining imaging performance as a function of subaperture configuration and of incoherent channel noise. SLSC images generated with a 2-D array yielded superior contrast-to-noise ratio (CNR) and texture SNR measurements over SLSC images made on a corresponding 1-D array and over B-mode imaging. SLSC images generated with square subapertures were found to be superior to SLSC images generated with subapertures of equal surface area that spanned the whole array in one dimension. Subaperture beamforming was found to have little effect on SLSC imaging performance for subapertures up to 8 × 8 elements in size on a 64 × 64 element transducer. Additionally, the use of 8 × 8, 4 × 4, and 2 × 2 element subapertures provided 8, 4, and 2 times improvement in channel SNR along with 2640-, 328-, and 25-fold reduction in computation time, respectively. These results indicate that volumetric SLSC imaging is readily applicable to existing 2-D arrays that employ subaperture beamforming. PMID:24960700

  8. Short-lag spatial coherence imaging on matrix arrays, part 1: Beamforming methods and simulation studies.

    PubMed

    Hyun, Dongwoon; Trahey, Gregg E; Jakovljevic, Marko; Dahl, Jeremy J

    2014-07-01

    Short-lag spatial coherence (SLSC) imaging is a beamforming technique that has demonstrated improved imaging performance compared with conventional B-mode imaging in previous studies. Thus far, the use of 1-D arrays has limited coherence measurements and SLSC imaging to a single dimension. Here, the SLSC algorithm is extended for use on 2-D matrix array transducers and applied in a simulation study examining imaging performance as a function of subaperture configuration and of incoherent channel noise. SLSC images generated with a 2-D array yielded superior contrast-to-noise ratio (CNR) and texture SNR measurements over SLSC images made on a corresponding 1-D array and over B-mode imaging. SLSC images generated with square subapertures were found to be superior to SLSC images generated with subapertures of equal surface area that spanned the whole array in one dimension. Subaperture beamforming was found to have little effect on SLSC imaging performance for subapertures up to 8 x 8 elements in size on a 64 × 64 element transducer. Additionally, the use of 8 x 8, 4 x 4, and 2 x 2 element subapertures provided 8, 4, and 2 times improvement in channel SNR along with 2640-, 328-, and 25-fold reduction in computation time, respectively. These results indicate that volumetric SLSC imaging is readily applicable to existing 2-D arrays that employ subaperture beamforming.

  9. Current Status of Hybrid PET/MRI in Oncologic Imaging

    PubMed Central

    Rosenkrantz, Andrew B.; Friedman, Kent; Chandarana, Hersh; Melsaether, Amy; Moy, Linda; Ding, Yu-Shin; Jhaveri, Komal; Beltran, Luis; Jain, Rajan

    2016-01-01

    OBJECTIVE This review article explores recent advancements in PET/MRI for clinical oncologic imaging. CONCLUSION Radiologists should understand the technical considerations that have made PET/MRI feasible within clinical workflows, the role of PET tracers for imaging various molecular targets in oncology, and advantages of hybrid PET/MRI compared with PET/CT. To facilitate this understanding, we discuss clinical examples (including gliomas, breast cancer, bone metastases, prostate cancer, bladder cancer, gynecologic malignancy, and lymphoma) as well as future directions, challenges, and areas for continued technical optimization for PET/MRI. PMID:26491894

  10. A study of image reconstruction algorithms for hybrid intensity interferometers

    NASA Astrophysics Data System (ADS)

    Crabtree, Peter N.; Murray-Krezan, Jeremy; Picard, Richard H.

    2011-09-01

    Phase retrieval is explored for image reconstruction using outputs from both a simulated intensity interferometer (II) and a hybrid system that combines the II outputs with partially resolved imagery from a traditional imaging telescope. Partially resolved imagery provides an additional constraint for the iterative phase retrieval process, as well as an improved starting point. The benefits of this additional a priori information are explored and include lower residual phase error for SNR values above 0.01, increased sensitivity, and improved image quality. Results are also presented for image reconstruction from II measurements alone, via current state-of-the-art phase retrieval techniques. These results are based on the standard hybrid input-output (HIO) algorithm, as well as a recent enhancement to HIO that optimizes step lengths in addition to step directions. The additional step length optimization yields a reduction in residual phase error, but only for SNR values greater than about 10. Image quality for all algorithms studied is quite good for SNR>=10, but it should be noted that the studied phase-recovery techniques yield useful information even for SNRs that are much lower.

  11. MAGPIS: A MULTI-ARRAY GALACTIC PLANE IMAGING SURVEY

    SciTech Connect

    Helfand, D J; Becker, R H; White, R L; Fallon, A; Tuttle, S

    2005-11-10

    We present the Multi-Array Galactic Plane Imaging Survey (MAGPIS), which maps portions of the first Galactic quadrant with an angular resolution, sensitivity and dynamic range that surpasses existing radio images of the Milky Way by more than an order of magnitude. The source detection threshold at 20 cm is in the range 1-2 mJy over the 85% of the survey region (5{sup o} < l < 32{sup o}, |b| < 0.8{sup o}) not covered by bright extended emission; the angular resolution is {approx} 6''. We catalog over 3000 discrete sources (diameters mostly < 30'') and present an atlas of {approx} 400 diffuse emission regions. New and archival data at 90 cm for the whole survey area are also presented. Comparison of our catalogs and images with the MSX mid-infrared data allow us to provide preliminary discrimination between thermal and non-thermal sources. We identify 49 high-probability supernova remnant candidates, increasing by a factor of seven the number of known remnants with diameters smaller than 50 in the survey region; several are pulsar wind nebula candidates and/or very small diameter remnants (D < 45''). We report the tentative identification of several hundred H II regions based on a comparison with the mid-IR data; they range in size from unresolved ultra-compact sources to large complexes of diffuse emission on scales of half a degree. In several of the latter regions, cospatial nonthermal emission illustrates the interplay between stellar death and birth. We comment briefly on plans for followup observations and our extension of the survey; when complemented by data from ongoing X-ray and mid-IR observations, we expect MAGPIS to provide an important contribution to our understanding of the birth and death of massive stars in the Milky Way.

  12. High-resolution imaging using a wideband MIMO radar system with two distributed arrays.

    PubMed

    Wang, Dang-wei; Ma, Xiao-yan; Chen, A-Lei; Su, Yi

    2010-05-01

    Imaging a fast maneuvering target has been an active research area in past decades. Usually, an array antenna with multiple elements is implemented to avoid the motion compensations involved in the inverse synthetic aperture radar (ISAR) imaging. Nevertheless, there is a price dilemma due to the high level of hardware complexity compared to complex algorithm implemented in the ISAR imaging system with only one antenna. In this paper, a wideband multiple-input multiple-output (MIMO) radar system with two distributed arrays is proposed to reduce the hardware complexity of the system. Furthermore, the system model, the equivalent array production method and the imaging procedure are presented. As compared with the classical real aperture radar (RAR) imaging system, there is a very important contribution in our method that the lower hardware complexity can be involved in the imaging system since many additive virtual array elements can be obtained. Numerical simulations are provided for testing our system and imaging method.

  13. Dual-view integral imaging 3D display by using orthogonal polarizer array and polarization switcher.

    PubMed

    Wang, Qiong-Hua; Ji, Chao-Chao; Li, Lei; Deng, Huan

    2016-01-11

    In this paper, a dual-view integral imaging three-dimensional (3D) display consisting of a display panel, two orthogonal polarizer arrays, a polarization switcher, and a micro-lens array is proposed. Two elemental image arrays for two different 3D images are presented by the display panel alternately, and the polarization switcher controls the polarization direction of the light rays synchronously. The two elemental image arrays are modulated by their corresponding and neighboring micro-lenses of the micro-lens array, and reconstruct two different 3D images in viewing zones 1 and 2, respectively. A prototype of the dual-view II 3D display is developed, and it has good performances.

  14. Hybrid CMOS SiPIN detectors as astronomical imagers

    NASA Astrophysics Data System (ADS)

    Simms, Lance Michael

    Charge Coupled Devices (CCDs) have dominated optical and x-ray astronomy since their inception in 1969. Only recently, through improvements in design and fabrication methods, have imagers that use Complimentary Metal Oxide Semiconductor (CMOS) technology gained ground on CCDs in scientific imaging. We are now in the midst of an era where astronomers might begin to design optical telescope cameras that employ CMOS imagers. The first three chapters of this dissertation are primarily composed of introductory material. In them, we discuss the potential advantages that CMOS imagers offer over CCDs in astronomical applications. We compare the two technologies in terms of the standard metrics used to evaluate and compare scientific imagers: dark current, read noise, linearity, etc. We also discuss novel features of CMOS devices and the benefits they offer to astronomy. In particular, we focus on a specific kind of hybrid CMOS sensor that uses Silicon PIN photodiodes to detect optical light in order to overcome deficiencies of commercial CMOS sensors. The remaining four chapters focus on a specific type of hybrid CMOS Silicon PIN sensor: the Teledyne Hybrid Visible Silicon PIN Imager (HyViSI). In chapters four and five, results from testing HyViSI detectors in the laboratory and at the Kitt Peak 2.1m telescope are presented. We present our laboratory measurements of the standard detector metrics for a number of HyViSI devices, ranging from 1k×1k to 4k×4k format. We also include a description of the SIDECAR readout circuit that was used to control the detectors. We then show how they performed at the telescope in terms of photometry, astrometry, variability measurement, and telescope focusing and guiding. Lastly, in the final two chapters we present results on detector artifacts such as pixel crosstalk, electronic crosstalk, and image persistence. One form of pixel crosstalk that has not been discussed elsewhere in the literature, which we refer to as Interpixel Charge

  15. Whole Genome Amplification of Labeled Viable Single Cells Suited for Array-Comparative Genomic Hybridization.

    PubMed

    Kroneis, Thomas; El-Heliebi, Amin

    2015-01-01

    Understanding details of a complex biological system makes it necessary to dismantle it down to its components. Immunostaining techniques allow identification of several distinct cell types thereby giving an inside view of intercellular heterogeneity. Often staining reveals that the most remarkable cells are the rarest. To further characterize the target cells on a molecular level, single cell techniques are necessary. Here, we describe the immunostaining, micromanipulation, and whole genome amplification of single cells for the purpose of genomic characterization. First, we exemplify the preparation of cell suspensions from cultured cells as well as the isolation of peripheral mononucleated cells from blood. The target cell population is then subjected to immunostaining. After cytocentrifugation target cells are isolated by micromanipulation and forwarded to whole genome amplification. For whole genome amplification, we use GenomePlex(®) technology allowing downstream genomic analysis such as array-comparative genomic hybridization.

  16. Customized Array Comparative Genomic Hybridization Analysis of 25 Phosphatase-encoding Genes in Colorectal Cancer Tissues

    PubMed Central

    LACZMANSKA, IZABELA; SKIBA, PAWEL; KARPINSKI, PAWEL; BEBENEK, MAREK; M. SASIADEK, MARIA

    2016-01-01

    Background/Aim: Molecular mechanisms of alterations in protein tyrosine phosphatases (PTPs) genes in cancer have been previously described and include chromosomal aberrations, gene mutations, and epigenetic silencing. However, little is known about small intragenic gains and losses that may lead to either changes in expression or enzyme activity and even loss of protein function. Materials and Methods: The aim of this study was to investigate 25 phosphatase genes using customized array comparative genomic hybridization in 16 sporadic colorectal cancer tissues. Results: The analysis revealed two unique small alterations: of 2 kb in PTPN14 intron 1 and of 1 kb in PTPRJ intron 1. We also found gains and losses of whole PTPs gene sequences covered by large chromosome aberrations. Conclusion: In our preliminary studies using high-resolution custom microarray we confirmed that PTPs are frequently subjected to whole-gene rearrangements in colorectal cancer, and we revealed that non-polymorphic intragenic changes are rare. PMID:28031238

  17. A hybrid computational model for ultrasound phased-array heating in presence of strongly scattering obstacles.

    PubMed

    Botros, Y Y; Volakis, J L; VanBaren, P; Ebbini, E S

    1997-11-01

    A computationally efficient hybrid ray-physical optics (HRPO) model is presented for the analysis and synthesis of multiple-focus ultrasound heating patterns through the human rib cage. In particular, a ray method is used to propagate the ultrasound fields from the source to the frontal plane of the rib cage. The physical-optics integration method is then employed to obtain the intensity pattern inside the rib cage. The solution of the matrix system is carried out by using the pseudo inverse technique to synthesize the desired heating pattern. The proposed technique guides the fields through the intercostal spacings between the solid ribs and, thus, minimal intensity levels are observed over the solid ribs. This simulation model allows for the design and optimization of large-aperture phased-array applicator systems for noninvasive ablative thermal surgery in the heart and liver through the rib cage.

  18. Array-Based Comparative Genomic Hybridization for the Genomewide Detection of Submicroscopic Chromosomal Abnormalities

    PubMed Central

    Vissers, Lisenka E. L. M. ; de Vries, Bert B. A. ; Osoegawa, Kazutoyo ; Janssen, Irene M. ; Feuth, Ton ; Choy, Chik On ; Straatman, Huub ; van der Vliet, Walter ; Huys, Erik H. L. P. G. ; van Rijk, Anke ; Smeets, Dominique ; van Ravenswaaij-Arts, Conny M. A. ; Knoers, Nine V. ; van der Burgt, Ineke ; de Jong, Pieter J. ; Brunner, Han G. ; van Kessel, Ad Geurts ; Schoenmakers, Eric F. P. M. ; Veltman, Joris A. 

    2003-01-01

    Microdeletions and microduplications, not visible by routine chromosome analysis, are a major cause of human malformation and mental retardation. Novel high-resolution, whole-genome technologies can improve the diagnostic detection rate of these small chromosomal abnormalities. Array-based comparative genomic hybridization allows such a high-resolution screening by hybridizing differentially labeled test and reference DNAs to arrays consisting of thousands of genomic clones. In this study, we tested the diagnostic capacity of this technology using ∼3,500 flourescent in situ hybridization–verified clones selected to cover the genome with an average of 1 clone per megabase (Mb). The sensitivity and specificity of the technology were tested in normal-versus-normal control experiments and through the screening of patients with known microdeletion syndromes. Subsequently, a series of 20 cytogenetically normal patients with mental retardation and dysmorphisms suggestive of a chromosomal abnormality were analyzed. In this series, three microdeletions and two microduplications were identified and validated. Two of these genomic changes were identified also in one of the parents, indicating that these are large-scale genomic polymorphisms. Deletions and duplications as small as 1 Mb could be reliably detected by our approach. The percentage of false-positive results was reduced to a minimum by use of a dye-swap-replicate analysis, all but eliminating the need for laborious validation experiments and facilitating implementation in a routine diagnostic setting. This high-resolution assay will facilitate the identification of novel genes involved in human mental retardation and/or malformation syndromes and will provide insight into the flexibility and plasticity of the human genome. PMID:14628292

  19. Phased Array Beamforming and Imaging in Composite Laminates Using Guided Waves

    NASA Technical Reports Server (NTRS)

    Tian, Zhenhua; Leckey, Cara A. C.; Yu, Lingyu

    2016-01-01

    This paper presents the phased array beamforming and imaging using guided waves in anisotropic composite laminates. A generic phased array beamforming formula is presented, based on the classic delay-and-sum principle. The generic formula considers direction-dependent guided wave properties induced by the anisotropic material properties of composites. Moreover, the array beamforming and imaging are performed in frequency domain where the guided wave dispersion effect has been considered. The presented phased array method is implemented with a non-contact scanning laser Doppler vibrometer (SLDV) to detect multiple defects at different locations in an anisotropic composite plate. The array is constructed of scan points in a small area rapidly scanned by the SLDV. Using the phased array method, multiple defects at different locations are successfully detected. Our study shows that the guided wave phased array method is a potential effective method for rapid inspection of large composite structures.

  20. Focal plane resolution and overlapped array time delay and integrate imaging

    NASA Astrophysics Data System (ADS)

    Grycewicz, Thomas J.; Cota, Stephen A.; Lomheim, Terrence S.; Kalman, Linda S.

    2010-06-01

    In this paper we model sub-pixel image registration for a generic earth-observing satellite system with a focal plane using two offset time delay and integrate (TDI) arrays in the focal plane to improve the achievable ground resolution over the resolution achievable with a single array. The modeling process starts with a high-resolution image as ground truth. The Parameterized Image Chain Analysis & Simulation Software (PICASSO) modeling tool is used to degrade the images to match the optical transfer function, sampling, and noise characteristics of the target system. The model outputs a pair of images with a separation close to the nominal half-pixel separation between the overlapped arrays. A registration estimation algorithm is used to measure the offset for image reconstruction. The two images are aligned and summed on a grid with twice the capture resolution. We compare the resolution in images between the inputs before overlap, the reconstructed image, and a simulation for the image which would have been captured on a focal plane with twice the resolution. We find the performance to always be better than the lower resolution baseline, and to approach the performance of the high-resolution array in the ideal case. We show that the overlapped array imager significantly outperforms both the conventional high- and low-resolution imagers in conditions with high image smear.

  1. Quantitative ultrasound images generated by a PE-CMOS sensor array: scatter modeling and image restoration

    NASA Astrophysics Data System (ADS)

    Liu, Chu-Chuan; Lo, Shih-Chung Ben; Freedman, Matthew T.; Lasser, Marvin E.; Lasser, Bob; Kula, John; Wang, Yue Joseph

    2007-03-01

    In the projection geometry, the detected ultrasound energy through a soft-tissue is mainly attributed to the attenuated primary intensity and the scatter intensity. In order to extract ultrasound image of attenuated primary beam out of the detected raw data, the scatter component must be carefully quantified for restoring the original image. In this study, we have designed a set of apparatus to modeling the ultrasound scattering in soft-tissue. The employed ultrasound imaging device was a C-Scan (projection) prototype using a 4th generation PE-CMOS sensor array (model I400, by Imperium Inc., Silver Spring, MD) as the detector. Right after the plane wave ultrasound transmitting through a soft-tissue mimicking material (Zerdine, by CIRS Inc., Norfolk, VA), a ring aperture is used to collimate the signal before reaching the acoustic lens and the PE-CMOS sensor. Three sets of collimated ring images were acquired and analyzed to obtain the scattering components as a function of the off-center distance. Several pathological specimens and breast phantoms consisting of simulated breast tissue with masses, cysts and microcalcifications were imaged by the same C-Scan imaging prototype. The restoration of these ultrasound images were performed by using a standard deconvolution computation. Our study indicated that the resultant images show shaper edges and detailed features as compared to their unprocessed counterparts.

  2. 7T transmit/receive arrays using ICE decoupling for human head MR imaging.

    PubMed

    Yan, Xinqiang; Zhang, Xiaoliang; Feng, Baotong; Ma, ChuangXin; Wei, Long; Xue, Rong

    2014-09-01

    In designing large-sized volume type phased array coils for human head imaging at ultrahigh fields, e.g., 7T, minimizing electromagnetic coupling among array elements is technically challenging. A new decoupling method based on induced current compensation or elimination (ICE) for a microstrip line planar array has recently been proposed. In this study, an eight-channel transmit/receive volume array with ICE-decoupled loop elements was built and investigated to demonstrate its feasibility and robustness for human head imaging at 7T. Isolation between adjacent loop elements was better than - 25 dB with a human head load. The worst-case of the isolation between all of the elements was about - 17.5 dB. All of the MRI experiments were performed on a 7T whole-body human MR scanner. Images of the phantom and human head were acquired and g-factor maps were measured and calculated to evaluate the performance of the coil array. Compared with the conventional capacitively decoupled array, the ICE-decoupled array demonstrated improved parallel imaging ability and had a higher SNR. The experimental results indicate that the transceiver array design with ICE decoupling technique might be a promising solution to designing high performance transmit/receive coil arrays for human head imaging at ultrahigh fields.

  3. Morphology-controlled ZnO nanowire arrays for tailored hybrid composites with high damping.

    PubMed

    Malakooti, Mohammad H; Hwang, Hyun-Sik; Sodano, Henry A

    2015-01-14

    Hybrid fiber reinforced composites using a nanoscale reinforcement of the interface have not reached their optimal performance in practical applications due to their complex design and the challenging assembly of their multiscale components. One promising approach to the fabrication of hybrid composites is the growth of zinc oxide (ZnO) nanowire arrays on the surface of carbon fibers to provide improved interfacial strength and out of plane reinforcement. However, this approach has been demonstrated mainly on fibers and thus still requires complex processing conditions. Here we demonstrate a simple approach to the fabrication of such composites through the growth of the nanowires on the fabric. The fabricated composites with nanostructured graded interphase not only exhibit remarkable damping enhancement but also stiffness improvement. It is demonstrated that these two extremely important properties of the composite can be controlled by tuning the morphology of the ZnO nanowires at the interface. Higher damping and flexural rigidity of these composites over traditional ones offer practical high-performance composites.

  4. [Attention deficit hyperactivity disorder analyzed with array comparative genome hybridization method. Case report].

    PubMed

    Duga, Balázs; Czakó, Márta; Komlósi, Katalin; Hadzsiev, Kinga; Sümegi, Katalin; Kisfali, Péter; Melegh, Márton; Melegh, Béla

    2014-10-05

    One of the most common psychiatric disorders during childhood is attention deficit hyperactivity disorder, which affects 5-6% of children worldwide. Symptoms include attention deficit, hyperactivity, forgetfulness and weak impulse control. The exact mechanism behind the development of the disease is unknown. However, current data suggest that a strong genetic background is responsible, which explains the frequent occurrence within a family. Literature data show that copy number variations are very common in patients with attention deficit hyperactivity disorder. The authors present a patient with attention deficit hyperactivity disorder who proved to have two approximately 400 kb heterozygous microduplications at 6p25.2 and 15q13.3 chromosomal regions detected by comparative genomic hybridization methods. Both duplications affect genes (6p25.2: SLC22A23; 15q13.3: CHRNA7) which may play a role in the development of attention deficit hyperactivity disorder. This case serves as an example of the wide spectrum of indication of the array comparative genome hybridization method.

  5. Conjugated polymer-silicon nanowire array hybrid Schottky diode for solar cell application.

    PubMed

    Zhang, Fute; Song, Tao; Sun, Baoquan

    2012-05-17

    The hybrid Schottky diode based on silicon nanowire arrays (SiNWs) and poly(3,4-ethylenedioxythiophene)/poly(styrenesulfonate) (PEDOT:PSS) has been fabricated for high performance solar cells. The length of SiNWs on a silicon substrate, which is prepared by metal-assisted chemical etching, can be tuned by adjusting the length of the etching time. In addition, the average distances between the adjacent silicon nanowires can be controlled by changing the immersing time in a saturated PCl(5) solution. The hybrid devices are made from the SiNWs with different wire lengths and various distances between adjacent wires by spin-casting PEDOT:PSS on the silicon substrates. It is found that the length and density play leading roles in the electric output characteristics. The device made from SiNWs with optimum morphology can achieve a power conversion efficiency of 7.3%, which is much improved in comparison with that of the planar one. The measurement of the transient photovoltage decay and the analysis of the current versus voltage curve indicate that the charge recombination process is a dominant factor on the device performance.

  6. Conjugated polymer-silicon nanowire array hybrid Schottky diode for solar cell application

    NASA Astrophysics Data System (ADS)

    Zhang, Fute; Song, Tao; Sun, Baoquan

    2012-05-01

    The hybrid Schottky diode based on silicon nanowire arrays (SiNWs) and poly(3,4-ethylenedioxythiophene)/poly(styrenesulfonate) (PEDOT:PSS) has been fabricated for high performance solar cells. The length of SiNWs on a silicon substrate, which is prepared by metal-assisted chemical etching, can be tuned by adjusting the length of the etching time. In addition, the average distances between the adjacent silicon nanowires can be controlled by changing the immersing time in a saturated PCl5 solution. The hybrid devices are made from the SiNWs with different wire lengths and various distances between adjacent wires by spin-casting PEDOT:PSS on the silicon substrates. It is found that the length and density play leading roles in the electric output characteristics. The device made from SiNWs with optimum morphology can achieve a power conversion efficiency of 7.3%, which is much improved in comparison with that of the planar one. The measurement of the transient photovoltage decay and the analysis of the current versus voltage curve indicate that the charge recombination process is a dominant factor on the device performance.

  7. Results of lower hybrid wave experiments using a dielectric loaded waveguide array antenna on TST-2

    NASA Astrophysics Data System (ADS)

    Wakatsuki, T.; Ejiri, A.; Shinya, T.; Takase, Y.; Furui, H.; Hiratsuka, J.; Imamura, K.; Inada, T.; Kakuda, H.; Kasahara, H.; Nagashima, Y.; Nakamura, K.; Nakanishi, A.; Oosako, T.; Saito, K.; Seki, T.; Shimpo, F.; Sonehara, M.; Togashi, H.; Tsuda, S.; Tsujii, N.; Yamaguchi, T.

    2014-02-01

    Lower hybrid current drive experiments were performed on the TST-2 spherical tokamak (R = 0.38 m, a = 0.25 m, Bt = 0.3 T, Ip = 0.1 MA). A waveguide array antenna consisting of four dielectric (alumina, ɛr = 10.0) loaded waveguides was used. The coupling characteristics were investigated over a wide range of input power (0.1 W - 40 kW). The reflection coefficient of this antenna increased when the input power exceeded approximately 1 kW. This result was compared with a numerical simulation based on the finite element method (FEM). The ponderomotive effect was calculated for the wave field calculated by COMSOL [1]. This calculation also showed variation of the reflection coefficient with the input power. Non-inductive plasma current start-up to 10 kA was demonstrated using 40 kW of lower hybrid wave (LHW) power. The current drive figure of merit (ηCD = IpneR/PRF) of this antenna was higher than that obtained using the combline antenna, which is designed to excite a travelling fast wave. The best current drive efficiency was obtained in the case in which the n∥ (= ck∥/ω) spectrum of the excited LHW was peaked around 9 and the toroidal field was higher than in previous experiments.

  8. Allelic genome structural variations in maize detected by array comparative genome hybridization.

    PubMed

    Beló, André; Beatty, Mary K; Hondred, David; Fengler, Kevin A; Li, Bailin; Rafalski, Antoni

    2010-01-01

    DNA polymorphisms such as insertion/deletions and duplications affecting genome segments larger than 1 kb are known as copy-number variations (CNVs) or structural variations (SVs). They have been recently studied in animals and humans by using array-comparative genome hybridization (aCGH), and have been associated with several human diseases. Their presence and phenotypic effects in plants have not been investigated on a genomic scale, although individual structural variations affecting traits have been described. We used aCGH to investigate the presence of CNVs in maize by comparing the genome of 13 maize inbred lines to B73. Analysis of hybridization signal ratios of 60,472 60-mer oligonucleotide probes between inbreds in relation to their location in the reference genome (B73) allowed us to identify clusters of probes that deviated from the ratio expected for equal copy-numbers. We found CNVs distributed along the maize genome in all chromosome arms. They occur with appreciable frequency in different germplasm subgroups, suggesting ancient origin. Validation of several CNV regions showed both insertion/deletions and copy-number differences. The nature of CNVs detected suggests CNVs might have a considerable impact on plant phenotypes, including disease response and heterosis.

  9. Hybrid PET/MR Imaging and Brain Connectivity

    PubMed Central

    Aiello, Marco; Cavaliere, Carlo; Salvatore, Marco

    2016-01-01

    In recent years, brain connectivity is gaining ever-increasing interest from the interdisciplinary research community. The study of brain connectivity is characterized by a multifaceted approach providing both structural and functional evidence of the relationship between cerebral regions at different scales. Although magnetic resonance (MR) is the most established imaging modality for investigating connectivity in vivo, the recent advent of hybrid positron emission tomography (PET)/MR scanners paved the way for more comprehensive investigation of brain organization and physiology. Due to the high sensitivity and biochemical specificity of radiotracers, combining MR with PET imaging may enrich our ability to investigate connectivity by introducing the concept of metabolic connectivity and cometomics and promoting new insights on the physiological and molecular bases underlying high-level neural organization. This review aims to describe and summarize the main methods of analysis of brain connectivity employed in MR imaging and nuclear medicine. Moreover, it will discuss practical aspects and state-of-the-art techniques for exploiting hybrid PET/MR imaging to investigate the relationship of physiological processes and brain connectivity. PMID:26973446

  10. Genome profiling of chondrosarcoma using oligonucleotide array-based comparative genomic hybridization.

    PubMed

    Hameed, Meera; Ulger, Celal; Yasar, Duygu; Limaye, Neha; Kurvathi, Rohini; Streck, Deanna; Benevenia, Joseph; Patterson, Francis; Dermody, James J; Toruner, Gokce A

    2009-07-15

    Chondrosarcomas of the bone are malignant hyaline cartilage-forming tumors with an annual incidence rate of 3.6% of all primary bone malignancies in the United States. Specimens of 25 chondrosarcomas (10 grade I, 9 grade II, 1 grade III, and 5 dedifferentiated) from 23 patients were collected from the Department of Pathology at the University Hospital at UMDNJ-New Jersey Medical School from 1996 to 2007. Array-based comparative genomic hybridization (array-CGH) studies were performed on frozen tumor specimens. Recurrent deletions observed in at least in six tumors were 5q13.2, 5q14.2 approximately q21.3, 6q12 approximately q13, 6q16 approximately q25.3, 9p24.2 approximately q12, and 9p21.3. There was a statistically significant association between high-grade tumor (grade III and dedifferentiated) and the recurrent genetic deletions at 5q14.2 approximately q21.3, 6q16 approximately q25.3, 9p24.2 approximately q12, and 9p21.3. There is consistency between increased levels of aneuploidy and the progression of chondrosarcoma from lower to higher grades.

  11. Composition of Ultra High Energy Cosmic Rays Observed by Telescope Array in Hybrid Mode

    NASA Astrophysics Data System (ADS)

    Hanlon, William; Telescope Array Collaboration

    2016-03-01

    The energy spectrum of cosmic rays exhibits several important features such as the knee (E ~10 15 . 5 eV), ankle (E ~10 18 . 7 eV), and high energy suppression (E ~10 19 . 8 eV). Cosmic ray chemical composition is the key to understanding their galactic and extragalactic sources as well as the origin of particle production and acceleration mechanisms. Energy dependent chemical composition is a fundamental input for models of cosmic ray sources and interstellar transport which may lead to competing explanations of the observed spectral features. Understanding composition will therefore allow one to distinguish between the different scenarios of cosmic ray origin, a decades old problem in astrophysics. In this talk we will describe measurements of ultra high energy cosmic ray composition performed by Telescope Array (TA) using Xmax measured in extended air showers (EAS) simultaneously observed by the TA surface array and TA fluorescence stations (called hybrid mode). Showers with primary energies above 1018 eV will be considered. We will also discuss improved methods of comparing the measured composition to EAS models.

  12. Custom Array Comparative Genomic Hybridization: the Importance of DNA Quality, an Expert Eye, and Variant Validation

    PubMed Central

    Lantieri, Francesca; Malacarne, Michela; Gimelli, Stefania; Santamaria, Giuseppe; Coviello, Domenico; Ceccherini, Isabella

    2017-01-01

    The presence of false positive and false negative results in the Array Comparative Genomic Hybridization (aCGH) design is poorly addressed in literature reports. We took advantage of a custom aCGH recently carried out to analyze its design performance, the use of several Agilent aberrations detection algorithms, and the presence of false results. Our study provides a confirmation that the high density design does not generate more noise than standard designs and, might reach a good resolution. We noticed a not negligible presence of false negative and false positive results in the imbalances call performed by the Agilent software. The Aberration Detection Method 2 (ADM-2) algorithm with a threshold of 6 performed quite well, and the array design proved to be reliable, provided that some additional filters are applied, such as considering only intervals with average absolute log2ratio above 0.3. We also propose an additional filter that takes into account the proportion of probes with log2ratio exceeding suggestive values for gain or loss. In addition, the quality of samples was confirmed to be a crucial parameter. Finally, this work raises the importance of evaluating the samples profiles by eye and the necessity of validating the imbalances detected. PMID:28287439

  13. Large 2D-arrays of size-controllable silver nanoparticles prepared by hybrid deposition

    NASA Astrophysics Data System (ADS)

    Dieu Thuy Ung, Thi; Hoa Nguyen, Thi; Liem Nguyen, Quang

    2016-09-01

    Two main results are presented in this paper. (i) Silver nanoparticles (AgNPs) with uniform size-distribution and controllability in the range of 20-50 nm were synthesized by seeding and growing at ambient conditions. The single-crystal Ag nano-seeds were created by reduction of AgNO3 in presence of citrate surfactant at 70 °C. Then, importantly, the fresh AgCl precursor was used in the presence of polyvinylpyrrolidone to adjust the reaction rate with ascorbic acid to generate Ag for growing on the surface of single-crystal Ag nano-seeds. The AgNPs size could be well-controlled by varying the amount of Ag nano-seeds while keeping the AgCl precursor concentration to be constant. (ii) The large 2D-arrays with homogeneous and dense monolayers of AgNPs were prepared on ITO substrates by hybrid method, in which the key technological point is the surface functionalization of AgNPs using mixed alkanethiols (dodecanethiol:octadecanethiol = 6:1). We have used the fabricated 2D-arrays from the 50 nm AgNPs as a surface enhanced Raman scattering substrate to take the Raman scattering spectra of rhodamine B (RhB), glucose and viral pathogen (H5N1) at very low concentrations of 10-10 M, 10-12 M and 4 ng μl-1, respectively.

  14. Fundamental limitations of reciprocal path imaging through the atmosphere with dilute subaperture arrays

    SciTech Connect

    Harvey, J.E.; Kotha, A.; Phillips, R.L.

    1994-12-31

    When synthesizing a large aperture with an array of smaller subapertures for high resolution imaging applications, it is important not only to arrange the subapertures to achieve minimal spatial frequency redundancy, but also to choose the size of the subapertures necessary to achieve the best possible image quality. Spurious or ``ghost`` images often occur even for non-redundant dilute subaperture arrays. In this paper the authors show that array configurations producing a uniform modulation transfer function will not exhibit these undesirable ghost images. A method is then presented for constructing both one-dimensional and two-dimensional configurations of dilute subaperture arrays that result in uniform spatial frequency response with arbitrarily high spatial resolution for reciprocal path imaging applications (i.e., imaging laser radar applications).

  15. Probe hybridization array typing: a binary typing method for Escherichia coli.

    PubMed

    Srinivasan, U; Zhang, L; France, A M; Ghosh, D; Shalaby, W; Xie, J; Marrs, C F; Foxman, B

    2007-01-01

    The ability to distinguish between Escherichia coli strains is critical for outbreak investigations. Binary typing, based on the presence or absence of genetic material, provides a high-throughput alternative to gel- and PCR-based typing techniques that generate complex banding patterns and lack uniform interpretation criteria. We developed, validated, and determined the discriminatory power of an E. coli binary typing method, probe hybridization array typing (PHAT). In PHAT, the absence or presence of genetic material is identified by using DNA hybridization to produce a reproducible and portable fingerprint for each genome. PHAT probes were generated from genome subtractive hybridization experiments. We PHAT typed the ECOR collection of strains from a variety of geographical locations, and 33 rectal E. coli strains selected from college-aged women with urinary tract infection. In the set of 33 human rectal strains, the discriminatory power of PHAT (98%) equaled that of multilocus sequence typing (MLST) and pulsed-field gel electrophoresis. However, for ECOR strains, which include nonhuman strains, the current set of PHAT probes was less discriminating than MLST, ribotyping, and enterobacterial repetitive intergenic consensus sequence PCR (80% versus 97, 92, and 97%, respectively). When we limited the analysis to ECOR strains of B2 and D lineage, which are associated with human infection, current PHAT probes were highly discriminatory (94%). PHAT can be applied in a high-throughput format (i.e., "library on a slide"), the discriminatory ability can be varied based on the probe set, and PHAT is readily adapted to other bacterial species with high variation in genetic content.

  16. Examining small molecule: HIV RNA interactions using arrayed imaging reflectometry

    NASA Astrophysics Data System (ADS)

    Chaimayo, Wanaruk; Miller, Benjamin L.

    2014-03-01

    Human Immunodeficiency Virus (HIV) has been the subject of intense research for more than three decades as it causes an uncurable disease: Acquired Immunodeficiency Syndrome, AIDS. In the pursuit of a medical treatment, RNAtargeted small molecules are emerging as promising targets. In order to understand the binding kinetics of small molecules and HIV RNA, association (ka) and dissociation (kd) kinetic constants must be obtained, ideally for a large number of sequences to assess selectivity. We have developed Aqueous Array Imaged Reflectometry (Aq-AIR) to address this challenge. Using a simple light interference phenomenon, Aq-AIR provides real-time high-throughput multiplex capabilities to detect binding of targets to surface-immobilized probes in a label-free microarray format. The second generation of Aq-AIR consisting of high-sensitivity CCD camera and 12-μL flow cell was fabricated. The system performance was assessed by real-time detection of MBNL1-(CUG)10 and neomycin B - HIV RNA bindings. The results establish this second-generation Aq-AIR to be able to examine small molecules binding to RNA sequences specific to HIV.

  17. 3-D Deep Penetration Photoacoustic Imaging with a 2-D CMUT Array.

    PubMed

    Ma, Te-Jen; Kothapalli, Sri Rajasekhar; Vaithilingam, Srikant; Oralkan, Omer; Kamaya, Aya; Wygant, Ira O; Zhuang, Xuefeng; Gambhir, Sanjiv S; Jeffrey, R Brooke; Khuri-Yakub, Butrus T

    2010-10-11

    In this work, we demonstrate 3-D photoacoustic imaging of optically absorbing targets embedded as deep as 5 cm inside a highly scattering background medium using a 2-D capacitive micromachined ultrasonic transducer (CMUT) array with a center frequency of 5.5 MHz. 3-D volumetric images and 2-D maximum intensity projection images are presented to show the objects imaged at different depths. Due to the close proximity of the CMUT to the integrated frontend circuits, the CMUT array imaging system has a low noise floor. This makes the CMUT a promising technology for deep tissue photoacoustic imaging.

  18. High-speed X-ray imaging pixel array detector for synchrotron bunch isolation

    PubMed Central

    Philipp, Hugh T.; Tate, Mark W.; Purohit, Prafull; Shanks, Katherine S.; Weiss, Joel T.; Gruner, Sol M.

    2016-01-01

    A wide-dynamic-range imaging X-ray detector designed for recording successive frames at rates up to 10 MHz is described. X-ray imaging with frame rates of up to 6.5 MHz have been experimentally verified. The pixel design allows for up to 8–12 frames to be stored internally at high speed before readout, which occurs at a 1 kHz frame rate. An additional mode of operation allows the integration capacitors to be re-addressed repeatedly before readout which can enhance the signal-to-noise ratio of cyclical processes. This detector, along with modern storage ring sources which provide short (10–100 ps) and intense X-ray pulses at megahertz rates, opens new avenues for the study of rapid structural changes in materials. The detector consists of hybridized modules, each of which is comprised of a 500 µm-thick silicon X-ray sensor solder bump-bonded, pixel by pixel, to an application-specific integrated circuit. The format of each module is 128 × 128 pixels with a pixel pitch of 150 µm. In the prototype detector described here, the three-side buttable modules are tiled in a 3 × 2 array with a full format of 256 × 384 pixels. The characteristics, operation, testing and application of the detector are detailed. PMID:26917125

  19. High-speed X-ray imaging pixel array detector for synchrotron bunch isolation

    DOE PAGES

    Philipp, Hugh T.; Tate, Mark W.; Purohit, Prafull; ...

    2016-01-28

    A wide-dynamic-range imaging X-ray detector designed for recording successive frames at rates up to 10 MHz is described. X-ray imaging with frame rates of up to 6.5 MHz have been experimentally verified. The pixel design allows for up to 8–12 frames to be stored internally at high speed before readout, which occurs at a 1 kHz frame rate. An additional mode of operation allows the integration capacitors to be re-addressed repeatedly before readout which can enhance the signal-to-noise ratio of cyclical processes. This detector, along with modern storage ring sources which provide short (10–100 ps) and intense X-ray pulses atmore » megahertz rates, opens new avenues for the study of rapid structural changes in materials. The detector consists of hybridized modules, each of which is comprised of a 500 µm-thick silicon X-ray sensor solder bump-bonded, pixel by pixel, to an application-specific integrated circuit. The format of each module is 128 × 128 pixels with a pixel pitch of 150 µm. In the prototype detector described here, the three-side buttable modules are tiled in a 3 × 2 array with a full format of 256 × 384 pixels. Lastly, we detail the characteristics, operation, testing and application of the detector.« less

  20. Packaging and characterization of orthogonal transfer array CCDs for the WIYN One Degree Imager

    NASA Astrophysics Data System (ADS)

    Lesser, Michael; Ouellette, David; Zareba, Grzegorz; Jacoby, George; Muller, Gary; Sawyer, David; Keyes, Joe; Bredthauer, Richard; Boggs, Kasey

    2009-02-01

    The WIYN One Degree Imager (ODI) will provide a one degree field of view for the WIYN 3.5 m telescope located on Kitt Peak near Tucson, Arizona. Its focal plane will consist of an 8x8 grid of Orthogonal Transfer Array (OTA) CCD detectors with nearly one billion pixels. The implementation of these detectors into the focal plane has required the development of several novel packaging and characterization techniques, which are the subject of this paper. We describe a new packaging/hybridization method in which the CCD die are directly bonded to aluminum nitride ceramic substrates which have indium bump on one side and brazed pins on the other. These custom packages allow good thermal conductivity, a flat imaging surface, four side buttability, and in situ testing of the devices during backside processing. We describe these carriers and the backside processing techniques used with them. We have also modified our cold probing system to screen these OTA die at wafer level to select the best candidates for backside processing. We describe these modifications and characterization results from several wafer lots.

  1. High-speed X-ray imaging pixel array detector for synchrotron bunch isolation

    SciTech Connect

    Philipp, Hugh T.; Tate, Mark W.; Purohit, Prafull; Shanks, Katherine S.; Weiss, Joel T.; Gruner, Sol M.

    2016-01-28

    A wide-dynamic-range imaging X-ray detector designed for recording successive frames at rates up to 10 MHz is described. X-ray imaging with frame rates of up to 6.5 MHz have been experimentally verified. The pixel design allows for up to 8–12 frames to be stored internally at high speed before readout, which occurs at a 1 kHz frame rate. An additional mode of operation allows the integration capacitors to be re-addressed repeatedly before readout which can enhance the signal-to-noise ratio of cyclical processes. This detector, along with modern storage ring sources which provide short (10–100 ps) and intense X-ray pulses at megahertz rates, opens new avenues for the study of rapid structural changes in materials. The detector consists of hybridized modules, each of which is comprised of a 500 µm-thick silicon X-ray sensor solder bump-bonded, pixel by pixel, to an application-specific integrated circuit. The format of each module is 128 × 128 pixels with a pixel pitch of 150 µm. In the prototype detector described here, the three-side buttable modules are tiled in a 3 × 2 array with a full format of 256 × 384 pixels. Lastly, we detail the characteristics, operation, testing and application of the detector.

  2. Ka-band Dielectric Waveguide Antenna Array for Millimeter Wave Active Imaging System

    NASA Astrophysics Data System (ADS)

    Fang, Weihai; Fei, Peng; Nian, Feng; Yang, Yujie; Feng, Keming

    2014-11-01

    Ka-band compact dielectric waveguide antenna array for active imaging system is given. Antenna array with WR28 metal waveguide direct feeding is specially designed with small size, high gain, good radiation pattern, easy realization, low insertion loss and low mutual coupling. One practical antenna array for 3-D active imaging system is shown with theoretic analysis and experimental results. The mutual coupling of transmitting and receiving units is less than -30dB, the gain from 26.5GHz to 40GHz is (12-16) dB. The results in this paper provide guidelines for the designing of millimeter wave dielectric waveguide antenna array.

  3. Ensuring quality of service for image transmission: hybrid loss protection.

    PubMed

    Grangetto, Marco; Magli, Enrico; Olmo, Gabriella

    2004-06-01

    We present hybrid loss protection as a new channel coding and packetization scheme for image transmission over nonprioritized lossy packet networks. The scheme employs an interleaver-based structure, and attempts to maximize the expected peak signal-to-noise ratio (PSNR) at the receiver given the constraint that the probability of failure, i.e., the probability that the PSNR of the decoded image is below a given threshold, is upper-bounded by a user-defined value. A new code-allocation algorithm is proposed, which employs Gilbert-Elliot modeling of the network statistics. Experimental results are provided in the case of transmission of images encoded by SPIHT and JPEG 2000 over a wireline, as well as a wireless UMTS-based Internet connection.

  4. Singulation for imaging ring arrays of capacitive micromachined ultrasonic transducers.

    PubMed

    Chang, Chienliu; Moini, Azadeh; Nikoozadeh, Amin; Sarioglu, Ali Fatih; Apte, Nikhil; Zhuang, Xuefeng; Khuri-Yakub, Butrus T

    2014-10-01

    Singulation of MEMS is a critical step in the transition from wafer-level to die-level devices. As is the case for capacitive micromachined ultrasound transducer (CMUT) ring arrays, an ideal singulation must protect the fragile membranes from the processing environment while maintaining a ring array geometry. The singulation process presented in this paper involves bonding a trench-patterned CMUT wafer onto a support wafer, deep reactive ion etching (DRIE) of the trenches, separating the CMUT wafer from the support wafer and de-tethering the CMUT device from the CMUT wafer. The CMUT arrays fabricated and singulated in this process were ring-shaped arrays, with inner and outer diameters of 5 mm and 10 mm, respectively. The fabricated CMUT ring arrays demonstrate the ability of this method to successfully and safely singulate the ring arrays and is applicable to any arbitrary 2D shaped MEMS device with uspended microstructures, taking advantage of the inherent planar attributes of DRIE.

  5. Strategies for Ultrasound Imaging Using Two-Dimensional Arrays

    NASA Astrophysics Data System (ADS)

    Velichko, A.; Wilcox, P. D.

    2010-02-01

    2D arrays are able to `view' a given defect from a range of angles leading to the possibility of obtaining richer characterization detail than possible with 1D arrays. This has clear benefits as real defects and engineering structures are three-dimensional. This paper describes different approaches to optimize 2D array design. Results are shown that illustrate the application of the proposed techniques to modeling and experimental data.

  6. Plasmon-enhanced second-harmonic generation from hybrid ZnO-covered silver-bowl array.

    PubMed

    Yang, Mingming; Shen, Shaoxin; Wang, Xiangjie; Yu, Binbin; Huang, Shengli; Xu, Die; Hu, Jiawen; Yang, Zhilin

    2016-06-02

    High-efficient, plasmon-enhanced nonlinear phenomena based on hybrid nanostructures, which combine nonlinear dielectrics with plasmonic metals, are of fundamental importance for various applications ranging from all-optical switching to imaging or bio-sensing. However, the high loss of the excitation energy in nanostructures and the poor spatial overlap between the plasmon enhancement and the bulk of nonlinear materials largely limit the operation of plasmon-enhanced nonlinear effects, resulting in low nonlinear conversion efficiency. Here, we design and fabricate a ZnO-covered, 2D silver-bowl array, which can serve as an efficient platform for plasmon-enhanced second-harmonic generation (PESHG). Validated by experiments and simulations, we demonstrate that the high spatial overlap between the near-field enhancement and the ZnO film plays the key role for this nanostructure-based PESHG process. The enhancement mainly originates from the fundamental wavelength-derived plasmon resonance, providing an enhancement factor of approximately 33 times. These results achieved pave the way for future applications, which require localized light sources at nanoscale.

  7. Plasmon-enhanced second-harmonic generation from hybrid ZnO-covered silver-bowl array

    NASA Astrophysics Data System (ADS)

    Yang, Mingming; Shen, Shaoxin; Wang, Xiangjie; Yu, Binbin; Huang, Shengli; Xu, Die; Hu, Jiawen; Yang, Zhilin

    2016-06-01

    High-efficient, plasmon-enhanced nonlinear phenomena based on hybrid nanostructures, which combine nonlinear dielectrics with plasmonic metals, are of fundamental importance for various applications ranging from all-optical switching to imaging or bio-sensing. However, the high loss of the excitation energy in nanostructures and the poor spatial overlap between the plasmon enhancement and the bulk of nonlinear materials largely limit the operation of plasmon-enhanced nonlinear effects, resulting in low nonlinear conversion efficiency. Here, we design and fabricate a ZnO-covered, 2D silver-bowl array, which can serve as an efficient platform for plasmon-enhanced second-harmonic generation (PESHG). Validated by experiments and simulations, we demonstrate that the high spatial overlap between the near-field enhancement and the ZnO film plays the key role for this nanostructure-based PESHG process. The enhancement mainly originates from the fundamental wavelength-derived plasmon resonance, providing an enhancement factor of approximately 33 times. These results achieved pave the way for future applications, which require localized light sources at nanoscale.

  8. Hybrid model prediction of guided wave array system detection sensitivity for the SHM of fatigue cracks in large structures

    NASA Astrophysics Data System (ADS)

    Fromme, P.

    2011-04-01

    Localized and distributed guided ultrasonic wave array systems allow for the efficient structural health monitoring of large structures, such as aircraft, ship hulls, or oil storage tanks. Permanently attached sensor arrays have been applied for the detection of corrosion and fatigue damage. A hybrid model has been developed for the efficient prediction of the sensitivity of guided waves array systems to detect through thickness and part-through fatigue cracks at different locations in plate structures. Using a point transmitter and receiver model for the wave propagation along the structure, the distances between sensor elements and potential defect locations are taken into account. The influence of the orientation of the crack relative to the transducer elements has been predicted from localized 3D Finite Element simulations. The directivity pattern of the scattered guided wave field has been shown to depend on the defect orientation and on the ratio of the characteristic defect size and depth to wavelength, and has been verified from experimental measurements. Good agreement was found and the localized amplitude and directivity patterns provide the basis for the quantification of the detection sensitivity for fatigue cracks. Using a hybrid model, the relative amplitudes of received pulses for different sensor array layouts can be calculated. From a comparison with the signal to noise ratio of the array system, detection capabilities can be predicted for various defect sizes and orientation. This provides a rapid tool for the development and optimization of guided wave array SHM systems.

  9. MR CAT scan: a modular approach for hybrid imaging.

    PubMed

    Hillenbrand, C; Hahn, D; Haase, A; Jakob, P M

    2000-07-01

    In this study, a modular concept for NMR hybrid imaging is presented. This concept essentially integrates different imaging modules in a sequential fashion and is therefore called CAT (combined acquisition technique). CAT is not a single specific measurement sequence, but rather a sequence design concept whereby distinct acquisition techniques with varying imaging parameters are employed in rapid succession in order to cover k-space. The power of the CAT approach is that it provides a high flexibility toward the acquisition optimization with respect to the available imaging time and the desired image quality. Important CAT sequence optimization steps include the appropriate choice of the k-space coverage ratio and the application of mixed bandwidth technology. Details of both the CAT methodology and possible CAT acquisition strategies, such as FLASH/EPI-, RARE/EPI- and FLASH/BURST-CAT are provided. Examples from imaging experiments in phantoms and healthy volunteers including mixed bandwidth acquisitions are provided to demonstrate the feasibility of the proposed CAT concept.

  10. Hybrid detection of lung nodules on CT scan images

    SciTech Connect

    Lu, Lin; Tan, Yongqiang; Schwartz, Lawrence H.; Zhao, Binsheng

    2015-09-15

    Purpose: The diversity of lung nodules poses difficulty for the current computer-aided diagnostic (CAD) schemes for lung nodule detection on computed tomography (CT) scan images, especially in large-scale CT screening studies. We proposed a novel CAD scheme based on a hybrid method to address the challenges of detection in diverse lung nodules. Methods: The hybrid method proposed in this paper integrates several existing and widely used algorithms in the field of nodule detection, including morphological operation, dot-enhancement based on Hessian matrix, fuzzy connectedness segmentation, local density maximum algorithm, geodesic distance map, and regression tree classification. All of the adopted algorithms were organized into tree structures with multi-nodes. Each node in the tree structure aimed to deal with one type of lung nodule. Results: The method has been evaluated on 294 CT scans from the Lung Image Database Consortium (LIDC) dataset. The CT scans were randomly divided into two independent subsets: a training set (196 scans) and a test set (98 scans). In total, the 294 CT scans contained 631 lung nodules, which were annotated by at least two radiologists participating in the LIDC project. The sensitivity and false positive per scan for the training set were 87% and 2.61%. The sensitivity and false positive per scan for the testing set were 85.2% and 3.13%. Conclusions: The proposed hybrid method yielded high performance on the evaluation dataset and exhibits advantages over existing CAD schemes. We believe that the present method would be useful for a wide variety of CT imaging protocols used in both routine diagnosis and screening studies.

  11. Recent developments in green light sensitive organic photodetectors for hybrid CMOS image sensor applications (Conference Presentation)

    NASA Astrophysics Data System (ADS)

    Leem, Dong-Seok; Lim, Seon-Jeong; Bulliard, Xavier; Lee, Gae Hwang; Lee, Kwang-Hee; Yun, Sungyoung; Yagi, Tadao; Satoh, Ryu-Ichi; Park, Kyung-Bae; Choi, Yeong Suk; Jin, Yong Wan; Lee, Sangyoon

    2016-09-01

    Typical CMOS colour image sensors consist of Si-based photodetectors (PDs) attached with colour filter arrays (i.e., the Bayer pattern). Recent trends on the development of high resolution image sensors, however, require downsizing the pixel dimension, which inevitably results in the loss of sensitivity due to the reduction in the photon acquisition. Very recently, hybrid stacks of organic photodetectors (OPDs) on conventional CMOS technologies have been proposed as one of the promising approaches to realise highly sensitive image sensors by doubling the light detecting area in the limited pixel size. Specifically, OPDs with orthogonal photosensitivity to green light and Si-based PDs with red and blue colour filters serve as the top and bottom photo-conversion layers, respectively. In this presentation, we will introduce the recent development of high performance green light sensitive OPDs and the demonstration of colour images from hybrid CMOS image sensors proposed. OPDs consisting of small molecule organic bulk heterto-junction structures, hole/electron buffer layers, and transparent top/bottom ITO electrodes exhibited peak external quantum efficiencies of 60-65% at 550-560 nm wavelengths and full width at half maximum of 120 nm at reverse bias of 3 V. Extremely low dark current densities in the range of 0.2-0.5 nA/cm2 at reverse bias of 3V and consequently high specific detectivities over 2×10^13 Jones were obtained from the developed OPD system. Further investigations in terms of the molecular structures of organic light absorbing materials, buffer materials, layer sequences, and even integration issues of the OPD on the CMOS will be described in detail.

  12. Experimental characterization, evaluation, and diagnosis of advanced hybrid infrared focal plane array electro-optical performance

    NASA Astrophysics Data System (ADS)

    Lomheim, Terrence S.; Schumann, Lee W.; Kohn, Stanley E.

    1998-07-01

    High performance scanning time-delay-and-integration and staring hybrid focal plane devices with very large formats, small pixel sizes, formidable frame and line rates, on-chip digital programmability, and high dynamic ranges, are being developed for a myriad of defense, civil, and commercial applications that span the spectral range from shortwave infrared (SWIR) to longwave infrared (LWIR). An essential part in the development of such new advanced hybrid infrared focal planes is empirical validation of their electro-optical (EO) performance. Many high-reliability, high-performance applications demand stringent and near flawless EO performance over a wide variety of operating conditions and environments. Verification of focal plane performance compliance over this wide range of parametric conditions requires the development and use of accurate, flexible, and statistically complete test methods and associated equipment. In this paper we review typical focal plane requirements, the ensuing measurement requirements (quantity, accuracy, repeatability, etc.), test methodologies, test equipment requirements, electronics and computer-based data acquisition requirements, statistical data analysis and display requirements, and associated issues. We also discuss special test requirements for verifying the performance of panchromatic thermal and multispectral imaging focal planes where characterization of dynamic modulation transfer function (MTF), and point-image response and optical overload is generally required. We briefly overview focal plane radiation testing. We conclude with a discussion of the technical challenges of characterizing future advanced hybrid focal plane testing where it is anticipated that analog-to- digital conversion will be included directly on focal plane devices, thus creating the scenario of 'photons-in-to-bits- out' within the focal plane itself.

  13. Hybrid UV Imager Containing Face-Up AlGaN/GaN Photodiodes

    NASA Technical Reports Server (NTRS)

    Zheng, Xinyu; Pain, Bedabrata

    2005-01-01

    A proposed hybrid ultraviolet (UV) image sensor would comprise a planar membrane array of face-up AlGaN/GaN photodiodes integrated with a complementary metal oxide/semiconductor (CMOS) readout-circuit chip. Each pixel in the hybrid image sensor would contain a UV photodiode on the AlGaN/GaN membrane, metal oxide/semiconductor field-effect transistor (MOSFET) readout circuitry on the CMOS chip underneath the photodiode, and a metal via connection between the photodiode and the readout circuitry (see figure). The proposed sensor design would offer all the advantages of comparable prior CMOS active-pixel sensors and AlGaN UV detectors while overcoming some of the limitations of prior (AlGaN/sapphire)/CMOS hybrid image sensors that have been designed and fabricated according to the methodology of flip-chip integration. AlGaN is a nearly ideal UV-detector material because its bandgap is wide and adjustable and it offers the potential to attain extremely low dark current. Integration of AlGaN with CMOS is necessary because at present there are no practical means of realizing readout circuitry in the AlGaN/GaN material system, whereas the means of realizing readout circuitry in CMOS are well established. In one variant of the flip-chip approach to integration, an AlGaN chip on a sapphire substrate is inverted (flipped) and then bump-bonded to a CMOS readout circuit chip; this variant results in poor quantum efficiency. In another variant of the flip-chip approach, an AlGaN chip on a crystalline AlN substrate would be bonded to a CMOS readout circuit chip; this variant is expected to result in narrow spectral response, which would be undesirable in many applications. Two other major disadvantages of flip-chip integration are large pixel size (a consequence of the need to devote sufficient area to each bump bond) and severe restriction on the photodetector structure. The membrane array of AlGaN/GaN photodiodes and the CMOS readout circuit for the proposed image sensor would

  14. Multi-channel microstrip transceiver arrays using harmonics for high field MR imaging in humans.

    PubMed

    Wu, Bing; Wang, Chunsheng; Lu, Jonathan; Pang, Yong; Nelson, Sarah J; Vigneron, Daniel B; Zhang, Xiaoliang

    2012-02-01

    Radio-frequency (RF) transceiver array design using primary and higher order harmonics for in vivo parallel magnetic resonance imaging imaging (MRI) and spectroscopic imaging is proposed. The improved electromagnetic decoupling performance, unique magnetic field distributions and high-frequency operation capabilities of higher-order harmonics of resonators would benefit transceiver arrays for parallel MRI, especially for ultrahigh field parallel MRI. To demonstrate this technique, microstrip transceiver arrays using first and second harmonic resonators were developed for human head parallel imaging at 7T. Phantom and human head images were acquired and evaluated using the GRAPPA reconstruction algorithm. The higher-order harmonic transceiver array design technique was also assessed numerically using FDTD simulation. Compared with regular primary-resonance transceiver designs, the proposed higher-order harmonic technique provided an improved g-factor and increased decoupling among resonant elements without using dedicated decoupling circuits, which would potentially lead to a better parallel imaging performance and ultimately faster and higher quality imaging. The proposed technique is particularly suitable for densely spaced transceiver array design where the increased mutual inductance among the elements becomes problematic. In addition, it also provides a simple approach to readily upgrade the channels of a conventional primary resonator microstrip array to a larger number for faster imaging.

  15. Implementation of total focusing method for phased array ultrasonic imaging on FPGA

    NASA Astrophysics Data System (ADS)

    Guo, JianQiang; Li, Xi; Gao, Xiaorong; Wang, Zeyong; Zhao, Quanke

    2015-02-01

    This paper describes a multi-FPGA imaging system dedicated for the real-time imaging using the Total Focusing Method (TFM) and Full Matrix Capture (FMC). The system was entirely described using Verilog HDL language and implemented on Altera Stratix IV GX FPGA development board. The whole algorithm process is to: establish a coordinate system of image and divide it into grids; calculate the complete acoustic distance of array element between transmitting array element and receiving array element, and transform it into index value; then index the sound pressure values from ROM and superimpose sound pressure values to get pixel value of one focus point; and calculate the pixel values of all focus points to get the final imaging. The imaging result shows that this algorithm has high SNR of defect imaging. And FPGA with parallel processing capability can provide high speed performance, so this system can provide the imaging interface, with complete function and good performance.

  16. Solid-state dye-sensitized solar cells based on ZnO nanoparticle and nanorod array hybrid photoanodes

    PubMed Central

    2011-01-01

    The effect of ZnO photoanode morphology on the performance of solid-state dye-sensitized solar cells (DSSCs) is reported. Four different structures of dye-loaded ZnO layers have been fabricated in conjunction with poly(3-hexylthiophene). A significant improvement in device efficiency with ZnO nanorod arrays as photoanodes has been achieved by filling the interstitial voids of the nanorod arrays with ZnO nanoparticles. The overall power conversion efficiency increases from 0.13% for a nanorod-only device to 0.34% for a device with combined nanoparticles and nanorod arrays. The higher device efficiency in solid-state DSSCs with hybrid nanorod/nanoparticle photoanodes is originated from both large surface area provided by nanoparticles for dye adsorption and efficient charge transport provided by the nanorod arrays to reduce the recombinations of photogenerated carriers. PMID:21884596

  17. Sparse Multi-Static Arrays for Near-Field Millimeter-Wave Imaging

    SciTech Connect

    Sheen, David M.

    2013-12-31

    This paper describes a novel design technique for sparse multi-static linear arrays. The methods described allow the development of densely sampled linear arrays suitable for high-resolution near-field imaging that require dramatically fewer antenna and switch elements than the previous state of the art. The techniques used are related to sparse array techniques used in radio astronomy applications, but differ significantly in design due to the transmit-receive nature of the arrays, and the application to linear arrays that achieve dense uniform sampling suitable for high-resolution near-field imaging. As many as 3 to 5 or more samples per antenna can be obtained, compared to 1 sample per antenna for the current state of the art. This could dramatically reduce cost and improve performance over current active millimeter-wave imaging systems.

  18. Designing of sparse 2D arrays for Lamb wave imaging using coarray concept

    NASA Astrophysics Data System (ADS)

    Ambroziński, Łukasz; Stepinski, Tadeusz; Uhl, Tadeusz

    2015-03-01

    2D ultrasonic arrays have considerable application potential in Lamb wave based SHM systems, since they enable equivocal damage imaging and even in some cases wave-mode selection. Recently, it has been shown that the 2D arrays can be used in SHM applications in a synthetic focusing (SF) mode, which is much more effective than the classical phase array mode commonly used in NDT. The SF mode assumes a single element excitation of subsequent transmitters and off-line processing the acquired data. In the simplest implementation of the technique, only single multiplexed input and output channels are required, which results in significant hardware simplification. Application of the SF mode for 2D arrays creates additional degrees of freedom during the design of the array topology, which complicates the array design process, however, it enables sparse array designs with performance similar to that of the fully populated dense arrays. In this paper we present the coarray concept to facilitate synthesis process of an array's aperture used in the multistatic synthetic focusing approach in Lamb waves-based imaging systems. In the coherent imaging, performed in the transmit/receive mode, the sum coarray is a morphological convolution of the transmit/receive sub-arrays. It can be calculated as the set of sums of the individual sub-arrays' elements locations. The coarray framework will be presented here using a an example of a star-shaped array. The approach will be discussed in terms of beampatterns of the resulting imaging systems. Both simulated and experimental results will be included.

  19. A Wide Dynamic Range Tapped Linear Array Image Sensor

    NASA Astrophysics Data System (ADS)

    Washkurak, William D.; Chamberlain, Savvas G.; Prince, N. Daryl

    1988-08-01

    magnitide are obtained. To achieve the short integration times necessary in acousto-optic applications. t he wide dynamic range detector has been implemented into a tapped array architecture with eight outputs and 256 photoelements. Operation of each 01)1,1)111 at 16 MHz yields detector integration times of 2 micro-seconds. Buried channel two phase CCD shift register technology is utilized to minimize image sensor noise improve video output rates and increase ease of operation.

  20. A CMOS visible silicon imager hybridized to a Rockwell 2RG multiplexer as a new detector for ground based astronomy

    NASA Astrophysics Data System (ADS)

    Dorn, Reinhold J.; Eschbaumer, Siegfried; Finger, Gert; Mehrgan, Leander; Meyer, Manfred; Stegmeier, Joerg

    2006-06-01

    For the past 25 years Charge Coupled Devices (CCDs) have been used as the preferred detector for ground based astronomy to detect visible photons. As an alternative to CCDs, silicon-based hybrid CMOS focal plane array technology is evolving rapidly. Visible hybrid detectors have a close synergy with IR detectors and are operated in a similar way. This paper presents recent test results for a Rockwell 2K x 2K silicon PIN diode array hybridized to a Hawaii-2RG multiplexer, the Hybrid Visible Silicon Imager (HyViSI). Since the capacitance of the integrating node of Si-PIN diodes is at least a factor of two smaller than the capacitance of the Hawaii-2RG IR detector pixel, lower noise was expected. However, those detectors suffer from interpixel capacitance which introduces an error to the value of the conversion factor measured with the photon transfer method. Therefore QE values have been overestimated by almost a factor of two in the past. Detailed test results on QE, noise, dark current, and other basic performance values as well as a discussion how to interpret the measured values will be presented. Two alternative methods, direct measurement of the nodal capacity and the use of Iron-55 X-rays to determine the actual nodal capacitance and hence the conversion factor will be briefly presented. PSF performance of this detector was analyzed in detail with an optical spot and single pixel reset measurement.

  1. Compensated individually addressable array technology for human breast imaging

    DOEpatents

    Lewis, D. Kent

    2003-01-01

    A method of forming broad bandwidth acoustic or microwave beams which encompass array design, array excitation, source signal preprocessing, and received signal postprocessing. This technique uses several different methods to achieve improvement over conventional array systems. These methods are: 1) individually addressable array elements; 2) digital-to-analog converters for the source signals; 3) inverse filtering from source precompensation; and 4) spectral extrapolation to expand the bandwidth of the received signals. The components of the system will be used as follows: 1) The individually addressable array allows scanning around and over an object, such as a human breast, without any moving parts. The elements of the array are broad bandwidth elements and efficient radiators, as well as detectors. 2) Digital-to-analog converters as the source signal generators allow virtually any radiated field to be created in the half-space in front of the array. 3) Preprocessing allows for corrections in the system, most notably in the response of the individual elements and in the ability to increase contrast and resolution of signal propagating through the medium under investigation. 4) Postprocessing allows the received broad bandwidth signals to be expanded in a process similar to analytic continuation. Used together, the system allows for compensation to create beams of any desired shape, control the wave fields generated to correct for medium differences, and improve contract and resolution in and through the medium.

  2. Applications of Microwave Antenna Array for Wireless Power Transmission and Radar Imaging in Complex Environment

    NASA Astrophysics Data System (ADS)

    Zhang, Ce

    The focus of my research interests lies in the application of microwave antenna array system and array signal processing techniques to problems in wireless power transmission and radar imaging. The two research areas share the same underlying mathematical principle of time reversality of electromagnetic wave propagation. Based on this principle, the array antenna system and the associated signal processing algorithm are further improved to adapt to different scenarios. In my dissertation, the rest part presents an optimal algorithm for wireless power transmission with beamforming array. The optimal weight distribution on antenna array elements is found based on time reversal eigenmode technique. Our method is adaptive to the medium of the channel and can be applied to arbitrarily positioned antenna without degradation of efficiency. This novel method is analytically studied and verified with numerical electromagnetic simulations. The second part presents a new problem called "Hard-Wall Radar Imaging" (HWRI) has been proposed when the electromagnetic waves cannot penetrate the shielding walls (such as metallic walls). The research methodology involves algorithm development combined with experimental results to gain more insights into the real microwave imaging system. First, we implemented the imaging system with the conventional time reversal DORT (Decomposition of Time-Reversal Operator) imaging algorithm and adapted it into a new signal processing technique (multiplicative array technique) to obtain the image in the proposed scenario. Second, after having identified the drawbacks of the rest imaging system, the imaging system is improved to distributed MIMO radar configuration. The new imaging algorithm is also developed based on the techniques of Direction-of-Arrival(DoA) estimation and adaptive nulling. From this algorithm, the experimental results show that the new imaging system can localize two targets correctly. To resolve the problem of spurious clutter

  3. Concepts leading to the IMAGE-100 hybrid interactive system

    NASA Technical Reports Server (NTRS)

    Mackin, T. F.; Sulester, J. M. (Principal Investigator)

    1979-01-01

    As LACIE Procedure 1 evolved from the Classification and Mensuration Subsystem smallfields procedures, it became evident that two computational systems would have merit-the LACIE/Earth Resources Interactive Processing System based on a large IBM-360 computer oriented for operational use with high computational throughput, and a smaller, highly interactive system based on a PDP 11-45 minicomputer and its display system, the IMAGE-100. The latter had advantages for certain phases; notably, interactive spectral aids could be implemented quite rapidly. This would allow testing and development of Procedure 1 before its implementation on the LACIE/Earth Resources Interactive Processing System. The resulting minicomputer system, called the Classification and Mensuration Subsystem IMAGE-100 Hybrid System, allowed Procedure-1 operations to be performed interactively, except for clustering, classification, and automatic selection of best acquisitions, which were offloaded to the LACIE/Earth Resources Interactive Processing System.

  4. Application of a target array Comparative Genomic Hybridization to prenatal diagnosis

    PubMed Central

    2010-01-01

    Background While conventional G-banded karyotyping still remains a gold standard in prenatal genetic diagnoses, the widespread adoption of array Comparative Genomic Hybridization (array CGH) technology for postnatal genetic diagnoses has led to increasing interest in the use of this same technology for prenatal diagnosis. We have investigated the value of our own designed DNA chip as a prenatal diagnostic tool for detecting submicroscopic deletions/duplications and chromosome aneuploidies. Methods We designed a target bacterial artificial chromosome (BAC)-based aCGH platform (MacArray™ M-chip), which specifically targets submicroscopic deletions/duplications for 26 known genetic syndromes of medical significance observed prenatally. To validate the DNA chip, we obtained genomic DNA from 132 reference materials generated from patients with 22 genetic diseases and 94 clinical amniocentesis samples obtained for karyotyping. Results In the 132 reference materials, all known genomic alterations were successfully identified. In the 94 clinical samples that were also subjected to conventional karyotyping, three cases of balanced chromosomal aberrations were not detected by aCGH. However, we identified eight cases of microdeletions in the Yq11.23 chromosomal region that were not found by conventional karyotyping. This region harbors the DAZ gene, and deletions may lead to non-obstructive spermatogenesis. Conclusions We have successfully designed and applied a BAC-based aCGH platform for prenatal diagnosis. This platform can be used in conjunction with conventional karyotyping and will provide rapid and accurate diagnoses for the targeted genomic regions while eliminating the need to interpret clinically-uncertain genomic regions. PMID:20576126

  5. Array-Based Genomic Comparative Hybridization Analysis of Field Strains of Mycoplasma hyopneumoniae▿ †

    PubMed Central

    Madsen, Melissa L.; Oneal, Michael J.; Gardner, Stuart W.; Strait, Erin L.; Nettleton, Dan; Thacker, Eileen L.; Minion, F. Chris

    2007-01-01

    Mycoplasma hyopneumoniae is the causative agent of porcine enzootic pneumonia and a major factor in the porcine respiratory disease complex. A clear understanding of the mechanisms of pathogenesis does not exist, although it is clear that M. hyopneumoniae adheres to porcine ciliated epithelium by action of a protein called P97. Previous studies have shown variation in the gene encoding the P97 cilium adhesin in different strains of M. hyopneumoniae, but the extent of genetic variation among field strains across the genome is not known. Since M. hyopneumoniae is a worldwide problem, it is reasonable to expect that a wide range of genetic variability may exist given all of the different breeds and housing conditions. This variation may impact the overall virulence of a single strain. Using microarray technology, this study examined the potential variation of 14 field strains compared to strain 232, on which the array was based. Genomic DNA was obtained, amplified with TempliPhi, and labeled indirectly with Alexa dyes. After genomic hybridization, the arrays were scanned and data were analyzed using a linear statistical model. The results indicated that genetic variation could be detected in all 14 field strains but across different loci, suggesting that variation occurs throughout the genome. Fifty-nine percent of the variable loci were hypothetical genes. Twenty-two percent of the lipoprotein genes showed variation in at least one field strain. A permutation test identified a location in the M. hyopneumoniae genome where there is spatial clustering of variability between the field strains and strain 232. PMID:17873054

  6. A 32-Channel Head Coil Array with Circularly Symmetric Geometry for Accelerated Human Brain Imaging

    PubMed Central

    Chu, Ying-Hua; Hsu, Yi-Cheng; Keil, Boris; Kuo, Wen-Jui; Lin, Fa-Hsuan

    2016-01-01

    The goal of this study is to optimize a 32-channel head coil array for accelerated 3T human brain proton MRI using either a Cartesian or a radial k-space trajectory. Coils had curved trapezoidal shapes and were arranged in a circular symmetry (CS) geometry. Coils were optimally overlapped to reduce mutual inductance. Low-noise pre-amplifiers were used to further decouple between coils. The SNR and noise amplification in accelerated imaging were compared to results from a head coil array with a soccer-ball (SB) geometry. The maximal SNR in the CS array was about 120% (1070 vs. 892) and 62% (303 vs. 488) of the SB array at the periphery and the center of the FOV on a transverse plane, respectively. In one-dimensional 4-fold acceleration, the CS array has higher averaged SNR than the SB array across the whole FOV. Compared to the SB array, the CS array has a smaller g-factor at head periphery in all accelerated acquisitions. Reconstructed images using a radial k-space trajectory show that the CS array has a smaller error than the SB array in 2- to 5-fold accelerations. PMID:26909652

  7. RNA Imaging with Multiplexed Error Robust Fluorescence in situ Hybridization

    PubMed Central

    Moffitt, Jeffrey R.; Zhuang, Xiaowei

    2016-01-01

    Quantitative measurements of both the copy number and spatial distribution of large fractions of the transcriptome in single-cells could revolutionize our understanding of a variety of cellular and tissue behaviors in both healthy and diseased states. Single-molecule Fluorescence In Situ Hybridization (smFISH)—an approach where individual RNAs are labeled with fluorescent probes and imaged in their native cellular and tissue context—provides both the copy number and spatial context of RNAs but has been limited in the number of RNA species that can be measured simultaneously. Here we describe Multiplexed Error Robust Fluorescence In Situ Hybridization (MERFISH), a massively parallelized form of smFISH that can image and identify hundreds to thousands of different RNA species simultaneously with high accuracy in individual cells in their native spatial context. We provide detailed protocols on all aspects of MERFISH, including probe design, data collection, and data analysis to allow interested laboratories to perform MERFISH measurements themselves. PMID:27241748

  8. MEMS switch integrated radio frequency coils and arrays for magnetic resonance imaging

    NASA Astrophysics Data System (ADS)

    Bulumulla, S. B.; Park, K. J.; Fiveland, E.; Iannotti, J.; Robb, F.

    2017-02-01

    Surface coils are widely used in magnetic resonance imaging and spectroscopy. While smaller diameter coils produce higher signal to noise ratio (SNR) closer to the coil, imaging larger fields of view or greater distance into the sample requires a larger overall size array or, in the case of a channel count limited system, larger diameter coils. In this work, we consider reconfiguring the geometry of coils and coil arrays such that the same coil or coil array may be used in multiple field of view imaging. A custom designed microelectromechanical systems switch, compatible with magnetic resonance imaging, is used to switch in/out conductive sections and components to reconfigure coils. The switch does not degrade the SNR and can be opened/closed in 10 μ s, leading to rapid reconfiguration. Results from a single coil, configurable between small/large configurations, and a two-coil phased array, configurable between spine/torso modes, are presented.

  9. First Results On The Imaging Capabilities Of A DROID Array In The UV/Visible

    SciTech Connect

    Hijmering, R. A.; Verhoeve, P.; Martin, D. D. E.; Venn, R.

    2009-12-16

    Within the SCAM project of the European Space Agency the next step in the development of a cryogenic optical photon counting imaging spectrometer would be to increase the field of view using DROIDs (Distributed Read-Out Imaging Detector). We present the results of the first system test using an array of 60 360x33.5 {mu}m{sup 2} DROIDs in a 3x20 format for optical photon detection. This is an increase in area by a factor of 5.5 compared to the successful S-Cam 3 detector. The responsivity of the DROID array tested is too low for actual use on the telescope. However the spatial resolution of {approx}35 {mu}m is just above the size of a virtual pixel and imaging capabilities of the array can be demonstrated. With increasing responsivity this will improve, yielding a DROID array which can be used as an astronomical optical photon counting imaging spectrometer.

  10. Simultaneous acquisition of spatial harmonics (SMASH): fast imaging with radiofrequency coil arrays.

    PubMed

    Sodickson, D K; Manning, W J

    1997-10-01

    SiMultaneous Acquisition of Spatial Harmonics (SMASH) is a new fast-imaging technique that increases MR image acquisition speed by an integer factor over existing fast-imaging methods, without significant sacrifices in spatial resolution or signal-to-noise ratio. Image acquisition time is reduced by exploiting spatial information inherent in the geometry of a surface coil array to substitute for some of the phase encoding usually produced by magnetic field gradients. This allows for partially parallel image acquisitions using many of the existing fast-imaging sequences. Unlike the data combination algorithms of prior proposals for parallel imaging, SMASH reconstruction involves a small set of MR signal combinations prior to Fourier transformation, which can be advantageous for artifact handling and practical implementation. A twofold savings in image acquisition time is demonstrated here using commercial phased array coils on two different MR-imaging systems. Larger time savings factors can be expected for appropriate coil designs.

  11. Array of liquid crystal polymer-based Fabry-Perot resonators for image selection by polarization

    NASA Astrophysics Data System (ADS)

    Lee, In-Ho; Yu, Eui-Sang; Kim, Se-Um; Lee, Sin-Doo

    2016-09-01

    We demonstrate an array of the Fabry-Perot (FP) resonators with a liquid crystal polymer (LCP) layer inside each resonant cavity for image selection by polarization of the incident light. In our approach, the LCP molecules in the array of the FP resonators for different images are photo-aligned in different directions. Under unpolarized light, no image is observed. For the incident light polarized parallel to the photo-alignment direction, only the image corresponding to the polarization state among the recorded images is visible due to the difference in the effective refractive index between different image regions in the array of the FP resonators. Our approach based on anisotropic FP resonators will be useful for the realization of highly efficient and low-cost anti-counterfeiting systems and security labels.

  12. Enhanced optical second harmonic generation in hybrid polymer nanoassemblies based on coupled surface plasmon resonance of a gold nanoparticle array

    NASA Astrophysics Data System (ADS)

    Ishifuji, Miki; Mitsuishi, Masaya; Miyashita, Tokuji

    2006-07-01

    Effective utilization of coupled surface plasmon resonance from gold nanoparticles was demonstrated experimentally for optoelectronic applications based on second-order nonlinear optics. Hybrid polymer nanoassemblies were constructed by manipulating gold nanoparticle arrays with nonlinear optical active polymer nanosheets to investigate the second harmonic generation. The gold nanoparticle arrays were assembled on heterodeposited polymer nanosheets. The second harmonic light intensity was enhanced by a factor of 8. The observed enhancement was attributed to coupling of surface plasmons between two adjacent gold nanoparticles, thereby enhancing the surface electromagnetic field around the nanoparticles at the fundamental light wavelength (1064nm).

  13. Monolithically integrated 20-channel optical add/drop multiplexer subsystem with hybrid-integrated 40-channel photodetector array

    NASA Astrophysics Data System (ADS)

    Schumacher, Andreas B.; Krabe, Detlef; Dieckroeger, Jens; Spott, Thorsten; Kraeker, Tobias; Martins, Evely; Zavrsnik, Miha; Schneider, Hartmut W.; Baumann, Ingo

    2003-03-01

    We built a 20 channel, 200 GHz, fully reconfigurable optical add-/drop multiplexer with integrated variable optical attenuators and power monitor diodes. A single planar lightwave circuit chip contains demultiplexer, switch array, attenuators and multiplexers. It also serves as an "optical motherboard" for a hybrid, flip-chip assembly containing four 10-channel photo detector arrays. A thermal management concept which considers both microscopic and macroscopic aspects of the device was developed. The final device exhibits an insertion loss of 9 dB from "in"- to "through"-port, a 1 dB bandwidth of >50 GHz and switch extinction ratios in excess of 40 dB.

  14. Diagnostic support for glaucoma using retinal images: a hybrid image analysis and data mining approach.

    PubMed

    Yu, Jin; Abidi, Syed Sibte Raza; Artes, Paul; McIntyre, Andy; Heywood, Malcolm

    2005-01-01

    The availability of modern imaging techniques such as Confocal Scanning Laser Tomography (CSLT) for capturing high-quality optic nerve images offer the potential for developing automatic and objective methods for diagnosing glaucoma. We present a hybrid approach that features the analysis of CSLT images using moment methods to derive abstract image defining features. The features are then used to train classifers for automatically distinguishing CSLT images of normal and glaucoma patient. As a first, in this paper, we present investigations in feature subset selction methods for reducing the relatively large input space produced by the moment methods. We use neural networks and support vector machines to determine a sub-set of moments that offer high classification accuracy. We demonstratee the efficacy of our methods to discriminate between healthy and glaucomatous optic disks based on shape information automatically derived from optic disk topography and reflectance images.

  15. Production and preliminary testing of multianalyte imaging sensor arrays

    SciTech Connect

    Richards, J.B.; Brown, S.B.; Milanovich, F.P.; Healey, B.G.; Chadha, S.; Walt, D.R.

    1994-11-01

    This report covers the production and preliminary testing of fiber optic sensors that contain a discrete array of analyte specific sensors on their distal ends. The development of the chemistries associated with this technology is covered elsewhere.

  16. Formulation Development and Evaluation of Hybrid Nanocarrier for Cancer Therapy: Taguchi Orthogonal Array Based Design

    PubMed Central

    Tekade, Rakesh K.; Chougule, Mahavir B.

    2013-01-01

    Taguchi orthogonal array design is a statistical approach that helps to overcome limitations associated with time consuming full factorial experimental design. In this study, the Taguchi orthogonal array design was applied to establish the optimum conditions for bovine serum albumin (BSA) nanocarrier (ANC) preparation. Taguchi method with L9 type of robust orthogonal array design was adopted to optimize the experimental conditions. Three key dependent factors namely, BSA concentration (% w/v), volume of BSA solution to total ethanol ratio (v : v), and concentration of diluted ethanolic aqueous solution (% v/v), were studied at three levels 3%, 4%, and 5% w/v; 1 : 0.75, 1 : 0.90, and 1 : 1.05 v/v; 40%, 70%, and 100% v/v, respectively. The ethanolic aqueous solution was used to impart less harsh condition for desolvation and attain controlled nanoparticle formation. The interaction plot studies inferred the ethanolic aqueous solution concentration to be the most influential parameter that affects the particle size of nanoformulation. This method (BSA, 4% w/v; volume of BSA solution to total ethanol ratio, 1 : 0.90 v/v; concentration of diluted ethanolic solution, 70% v/v) was able to successfully develop Gemcitabine (G) loaded modified albumin nanocarrier (M-ANC-G) of size 25.07 ± 2.81 nm (ζ = −23.03 ± 1.015 mV) as against to 78.01 ± 4.99 nm (ζ = −24.88 ± 1.37 mV) using conventional method albumin nanocarrier (C-ANC-G). Hybrid nanocarriers were generated by chitosan layering (solvent gelation technique) of respective ANC to form C-HNC-G and M-HNC-G of sizes 125.29 ± 5.62 nm (ζ = 12.01 ± 0.51 mV) and 46.28 ± 2.21 nm (ζ = 15.05 ± 0.39 mV), respectively. Zeta potential, entrapment, in vitro release, and pH-based stability studies were investigated and influence of formulation parameters are discussed. Cell-line-based cytotoxicity assay (A549 and H460 cells) and cell internalization assay (H460 cell line) were

  17. Photoconductive terahertz near-field detector with a hybrid nanoantenna array cavity

    DOE PAGES

    Mitrofanov, Oleg; Brener, Igal; Luk, Ting S.; ...

    2015-11-19

    Nanoscale structuring of optical materials leads to modification of their properties and can be used for improving efficiencies of photonic devices and for enabling new functionalities. In ultrafast optoelectronic switches for generation and detection of terahertz (THz) radiation, incorporation of nanostructures allows us to overcome inherent limitations of photoconductive materials. We propose and demonstrate a nanostructured photoconductive THz detector for sampling highly localized THz fields, down to the level of λ/150. The nanostructure that consists of an array of optical nanoantennas and a distributed Bragg reflector forms a hybrid cavity, which traps optical gate pulses within the photoconductive layer. Themore » effect of photon trapping is observed as enhanced absorption at a designed wavelength. This optically thin photoconductive THz detector allows us to detect highly confined evanescent THz fields coupled through a deeply subwavelength aperture as small as 2 μm (λ/150 at 1 THz). As a result, by monolithically integrating the THz detector with apertures ranging from 2 to 5 μm we realize higher spatial resolution and higher sensitivity in aperture-type THz near-field microscopy and THz time-domain spectroscopy.« less

  18. Array comparative genomic hybridization-based characterization of genetic alterations in pulmonary neuroendocrine tumors.

    PubMed

    Voortman, Johannes; Lee, Jih-Hsiang; Killian, Jonathan Keith; Suuriniemi, Miia; Wang, Yonghong; Lucchi, Marco; Smith, William I; Meltzer, Paul; Wang, Yisong; Giaccone, Giuseppe

    2010-07-20

    The goal of this study was to characterize and classify pulmonary neuroendocrine tumors based on array comparative genomic hybridization (aCGH). Using aCGH, we performed karyotype analysis of 33 small cell lung cancer (SCLC) tumors, 13 SCLC cell lines, 19 bronchial carcinoids, and 9 gastrointestinal carcinoids. In contrast to the relatively conserved karyotypes of carcinoid tumors, the karyotypes of SCLC tumors and cell lines were highly aberrant. High copy number (CN) gains were detected in SCLC tumors and cell lines in cytogenetic bands encoding JAK2, FGFR1, and MYC family members. In some of those samples, the CN of these genes exceeded 100, suggesting that they could represent driver alterations and potential drug targets in subgroups of SCLC patients. In SCLC tumors, as well as bronchial carcinoids and carcinoids of gastrointestinal origin, recurrent CN alterations were observed in 203 genes, including the RB1 gene and 59 microRNAs of which 51 locate in the DLK1-DIO3 domain. These findings suggest the existence of partially shared CN alterations in these tumor types. In contrast, CN alterations of the TP53 gene and the MYC family members were predominantly observed in SCLC. Furthermore, we demonstrated that the aCGH profile of SCLC cell lines highly resembles that of clinical SCLC specimens. Finally, by analyzing potential drug targets, we provide a genomics-based rationale for targeting the AKT-mTOR and apoptosis pathways in SCLC.

  19. Photoconductive terahertz near-field detector with a hybrid nanoantenna array cavity

    SciTech Connect

    Mitrofanov, Oleg; Brener, Igal; Luk, Ting S.; Reno, John L.

    2015-11-19

    Nanoscale structuring of optical materials leads to modification of their properties and can be used for improving efficiencies of photonic devices and for enabling new functionalities. In ultrafast optoelectronic switches for generation and detection of terahertz (THz) radiation, incorporation of nanostructures allows us to overcome inherent limitations of photoconductive materials. We propose and demonstrate a nanostructured photoconductive THz detector for sampling highly localized THz fields, down to the level of λ/150. The nanostructure that consists of an array of optical nanoantennas and a distributed Bragg reflector forms a hybrid cavity, which traps optical gate pulses within the photoconductive layer. The effect of photon trapping is observed as enhanced absorption at a designed wavelength. This optically thin photoconductive THz detector allows us to detect highly confined evanescent THz fields coupled through a deeply subwavelength aperture as small as 2 μm (λ/150 at 1 THz). As a result, by monolithically integrating the THz detector with apertures ranging from 2 to 5 μm we realize higher spatial resolution and higher sensitivity in aperture-type THz near-field microscopy and THz time-domain spectroscopy.

  20. Making hybrid [n]-rotaxanes as supramolecular arrays of molecular electron spin qubits

    PubMed Central

    Fernandez, Antonio; Ferrando-Soria, Jesus; Pineda, Eufemio Moreno; Tuna, Floriana; Vitorica-Yrezabal, Iñigo J.; Knappke, Christiane; Ujma, Jakub; Muryn, Christopher A.; Timco, Grigore A.; Barran, Perdita E.; Ardavan, Arzhang; Winpenny, Richard E.P.

    2016-01-01

    Quantum information processing (QIP) would require that the individual units involved—qubits—communicate to other qubits while retaining their identity. In many ways this resembles the way supramolecular chemistry brings together individual molecules into interlocked structures, where the assembly has one identity but where the individual components are still recognizable. Here a fully modular supramolecular strategy has been to link hybrid organic–inorganic [2]- and [3]-rotaxanes into still larger [4]-, [5]- and [7]-rotaxanes. The ring components are heterometallic octanuclear [Cr7NiF8(O2CtBu)16]– coordination cages and the thread components template the formation of the ring about the organic axle, and are further functionalized to act as a ligand, which leads to large supramolecular arrays of these heterometallic rings. As the rings have been proposed as qubits for QIP, the strategy provides a possible route towards scalable molecular electron spin devices for QIP. Double electron–electron resonance experiments demonstrate inter-qubit interactions suitable for mediating two-qubit quantum logic gates. PMID:26742716

  1. New Tools for Embryo Selection: Comprehensive Chromosome Screening by Array Comparative Genomic Hybridization

    PubMed Central

    Cobo, Ana Cristina; Milán, Miguel; Al-Asmar, Nasser; García-Herrero, Sandra; Mir, Pere; Simón, Carlos

    2014-01-01

    The objective of this study was to evaluate the usefulness of comprehensive chromosome screening (CCS) using array comparative genomic hybridization (aCGH). The study included 1420 CCS cycles for recurrent miscarriage (n = 203); repetitive implantation failure (n = 188); severe male factor (n = 116); previous trisomic pregnancy (n = 33); and advanced maternal age (n = 880). CCS was performed in cycles with fresh oocytes and embryos (n = 774); mixed cycles with fresh and vitrified oocytes (n = 320); mixed cycles with fresh and vitrified day-2 embryos (n = 235); and mixed cycles with fresh and vitrified day-3 embryos (n = 91). Day-3 embryo biopsy was performed and analyzed by aCGH followed by day-5 embryo transfer. Consistent implantation (range: 40.5–54.2%) and pregnancy rates per transfer (range: 46.0–62.9%) were obtained for all the indications and independently of the origin of the oocytes or embryos. However, a lower delivery rate per cycle was achieved in women aged over 40 years (18.1%) due to the higher percentage of aneuploid embryos (85.3%) and lower number of cycles with at least one euploid embryo available per transfer (40.3%). We concluded that aneuploidy is one of the major factors which affect embryo implantation. PMID:24877108

  2. Optimization of element length for imaging small volumetric reflectors with linear ultrasonic arrays

    NASA Astrophysics Data System (ADS)

    Barber, T. S.; Wilcox, P. D.; Nixon, A. D.

    2016-02-01

    A 3D ultrasonic simulation study is presented, aimed at understanding the effect of element length for imaging small volumetric flaws with linear arrays in ultrasonically noisy materials. The geometry of a linear array can be described by the width, pitch and total number of the elements along with the length perpendicular to imaging plane. This paper is concerned with the latter parameter, which tends to be ignored in array optimization studies and is often chosen arbitrarily for industrial array inspections. A 3D analytical model based on imaging a point target is described, validated and used to make calculations of relative Signal-to-Noise Ratio (SNR) as a function of element length. SNR is found to be highly sensitive to element length with a 12dB variation observed over the length range investigated. It is then demonstrated that the optimal length can be predicted directly from the Point Spread Function (PSF) of the imaging system as well as the natural focal point of the array element from 2D beam profiles perpendicular to the imaging plane. This result suggests that the optimal length for any imaging position can be predicted without the need for a full 3D model and is independent of element pitch and the number of elements. Array element design guidelines are then described with respect to wavelength and extensions of these results are discussed for application to realistically-sized defects and coarse-grained materials.

  3. Integral imaging using phase-only LCoS spatial light modulators as Fresnel lenslet arrays.

    PubMed

    Yöntem, Ali Özgür; Onural, Levent

    2011-11-01

    We present a digital integral imaging system. A Fresnel lenslet array pattern is written on a phase-only LCoS spatial light modulator device (SLM) to replace the regular analog lenslet array in a conventional integral imaging system. We theoretically analyze the capture part of the proposed system based on Fresnel wave propagation formulation. Because of pixelation and quantization of the lenslet array pattern, higher diffraction orders and multiple focal points emerge. Because of the multiple focal planes introduced by the discrete lenslets, multiple image planes are observed. The use of discrete lenslet arrays also causes some other artifacts on the recorded elemental images. The results reduce to those available in the literature when the effects introduced by the discrete nature of the lenslets are omitted. We performed simulations of the capture part. It is possible to obtain the elemental images with an acceptable visual quality. We also constructed an optical integral imaging system with both capture and display parts using the proposed discrete Fresnel lenslet array written on a SLM. Optical results when self-luminous objects, such as an LED array, are used indicate that the proposed system yields satisfactory results.

  4. A mobile ferromagnetic shape detection sensor using a Hall sensor array and magnetic imaging.

    PubMed

    Misron, Norhisam; Shin, Ng Wei; Shafie, Suhaidi; Marhaban, Mohd Hamiruce; Mailah, Nashiren Farzilah

    2011-01-01

    This paper presents a mobile Hall sensor array system for the shape detection of ferromagnetic materials that are embedded in walls or floors. The operation of the mobile Hall sensor array system is based on the principle of magnetic flux leakage to describe the shape of the ferromagnetic material. Two permanent magnets are used to generate the magnetic flux flow. The distribution of magnetic flux is perturbed as the ferromagnetic material is brought near the permanent magnets and the changes in magnetic flux distribution are detected by the 1-D array of the Hall sensor array setup. The process for magnetic imaging of the magnetic flux distribution is done by a signal processing unit before it displays the real time images using a netbook. A signal processing application software is developed for the 1-D Hall sensor array signal acquisition and processing to construct a 2-D array matrix. The processed 1-D Hall sensor array signals are later used to construct the magnetic image of ferromagnetic material based on the voltage signal and the magnetic flux distribution. The experimental results illustrate how the shape of specimens such as square, round and triangle shapes is determined through magnetic images based on the voltage signal and magnetic flux distribution of the specimen. In addition, the magnetic images of actual ferromagnetic objects are also illustrated to prove the functionality of mobile Hall sensor array system for actual shape detection. The results prove that the mobile Hall sensor array system is able to perform magnetic imaging in identifying various ferromagnetic materials.

  5. A Flexible Annular-Array Imaging Platform for Micro-Ultrasound

    PubMed Central

    Qiu, Weibao; Yu, Yanyan; Chabok, Hamid Reza; Liu, Cheng; Tsang, Fu Keung; Zhou, Qifa; Shung, K. Kirk; Zheng, Hairong; Sun, Lei

    2013-01-01

    Micro-ultrasound is an invaluable imaging tool for many clinical and preclinical applications requiring high resolution (approximately several tens of micrometers). Imaging systems for micro-ultrasound, including single-element imaging systems and linear-array imaging systems, have been developed extensively in recent years. Single-element systems are cheaper, but linear-array systems give much better image quality at a higher expense. Annular-array-based systems provide a third alternative, striking a balance between image quality and expense. This paper presents the development of a novel programmable and real-time annular-array imaging platform for micro-ultrasound. It supports multi-channel dynamic beamforming techniques for large-depth-of-field imaging. The major image processing algorithms were achieved by a novel field-programmable gate array technology for high speed and flexibility. Real-time imaging was achieved by fast processing algorithms and high-speed data transfer interface. The platform utilizes a printed circuit board scheme incorporating state-of-the-art electronics for compactness and cost effectiveness. Extensive tests including hardware, algorithms, wire phantom, and tissue mimicking phantom measurements were conducted to demonstrate good performance of the platform. The calculated contrast-to-noise ratio (CNR) of the tissue phantom measurements were higher than 1.2 in the range of 3.8 to 8.7 mm imaging depth. The platform supported more than 25 images per second for real-time image acquisition. The depth-of-field had about 2.5-fold improvement compared to single-element transducer imaging. PMID:23287923

  6. A flexible annular-array imaging platform for micro-ultrasound.

    PubMed

    Qiu, Weibao; Yu, Yanyan; Chabok, Hamid Reza; Liu, Cheng; Tsang, Fu Keung; Zhou, Qifa; Shung, K Kirk; Zheng, Hairong; Sun, Lei

    2013-01-01

    Micro-ultrasound is an invaluable imaging tool for many clinical and preclinical applications requiring high resolution (approximately several tens of micrometers). Imaging systems for micro-ultrasound, including single-element imaging systems and linear-array imaging systems, have been developed extensively in recent years. Single-element systems are cheaper, but linear-array systems give much better image quality at a higher expense. Annular-array-based systems provide a third alternative, striking a balance between image quality and expense. This paper presents the development of a novel programmable and real-time annular-array imaging platform for micro-ultrasound. It supports multi-channel dynamic beamforming techniques for large-depth-of-field imaging. The major image processing algorithms were achieved by a novel field-programmable gate array technology for high speed and flexibility. Real-time imaging was achieved by fast processing algorithms and high-speed data transfer interface. The platform utilizes a printed circuit board scheme incorporating state-of-the-art electronics for compactness and cost effectiveness. Extensive tests including hardware, algorithms, wire phantom, and tissue mimicking phantom measurements were conducted to demonstrate good performance of the platform. The calculated contrast-to-noise ratio (CNR) of the tissue phantom measurements were higher than 1.2 in the range of 3.8 to 8.7 mm imaging depth. The platform supported more than 25 images per second for real-time image acquisition. The depth-of-field had about 2.5-fold improvement compared to single-element transducer imaging.

  7. Association between chromosomal aberration of COX8C and tethered spinal cord syndrome: array-based comparative genomic hybridization analysis

    PubMed Central

    Zhao, Qiu-jiong; Bai, Shao-cong; Cheng, Cheng; Tao, Ben-zhang; Wang, Le-kai; Liang, Shuang; Yin, Ling; Hang, Xing-yi; Shang, Ai-jia

    2016-01-01

    Copy number variations have been found in patients with neural tube abnormalities. In this study, we performed genome-wide screening using high-resolution array-based comparative genomic hybridization in three children with tethered spinal cord syndrome and two healthy parents. Of eight copy number variations, four were non-polymorphic. These non-polymorphic copy number variations were associated with Angelman and Prader-Willi syndromes, and microcephaly. Gene function enrichment analysis revealed that COX8C, a gene associated with metabolic disorders of the nervous system, was located in the copy number variation region of Patient 1. Our results indicate that array-based comparative genomic hybridization can be used to diagnose tethered spinal cord syndrome. Our results may help determine the pathogenesis of tethered spinal cord syndrome and prevent occurrence of this disease. PMID:27651783

  8. Cloth-based hybridization array system for the detection of Clostridium botulinum type A, B, E, and F neurotoxin genes.

    PubMed

    Gauthier, M; Cadieux, B; Austin, J W; Blais, B W

    2005-07-01

    A simple cloth-based hybridization array system was developed for the characterization of Clostridium botulinum isolates based on the botulinum neurotoxin serotype. Bacterial isolates were subjected to a multiplex PCR incorporating digoxigenin-dUTP and primers targeting the four botulinum neurotoxin gene serotypes (A, B, E, and F) predominantly involved in human illness, followed by hybridization of the amplicons with an array of toxin gene-specific oligonucleotide probes immobilized on polyester cloth and subsequent immunoenzymatic assay of the bound digoxigenin label. This system provided sensitive and specific detection of the different botulinum neurotoxin gene markers in a variety of C. botulinum strains, exhibiting the expected patterns of reactivity with a panel of target and nontarget organisms.

  9. Design of high-T{sub c} superconducting bolometers for a far infrared imaging array

    SciTech Connect

    Verghese, S.; Richards, P.L.; Fork, D.K.; Char, K.; Geballe, T.H.

    1992-08-01

    The design of high-{Tc} superconducting bolometers for use in a far infrared imaging array from wavelengths 30--100{mu}m is discussed. Measurements of the voltage noise in thin films of YBa{sub 2}CU{sub 3}O{sub 7-{var_sigma}} on yttria-stabilized zirconia buffer layers on silicon substrates are used to make performance estimates. Useful opportunities exist for imaging and spectroscopy with bolometer arrays made on micro-machined silicon membranes. A circuit on each pixel which performs some signal integration can improve the sensitivity of large two-dimensional arrays of bolometers which use multiplexed readout amplifiers.

  10. Ultrasonic measurement models for imaging with phased arrays

    NASA Astrophysics Data System (ADS)

    Schmerr, Lester W., Jr.; Engle, Brady J.; Sedov, Alexander; Li, Xiongbing

    2014-02-01

    Ultrasonic imaging measurement models (IMMs) are developed that generate images of flaws by inversion of ultrasonic measurement models. These IMMs are generalizations of the synthetic aperture focusing technique (SAFT) and the total focusing method (TFM). A special case when the flaw is small is shown to generalize physical optics far field inverse scattering (POFFIS) images. The ultrasonic IMMs provide a rational basis for generating and understanding the ultrasonic images produced by delay-and-sum imaging methods.

  11. Mid-Range Coil Array for Magnetic Resonance Imaging of Small Animals

    SciTech Connect

    Solis, S. E.; Tomasi, D.; Rodriguez, A. O.

    2008-08-11

    The vast majority of articles on MRI RF coils over the past two decades have focused on large coils, where sample losses dominate, or on micro-coils, where sample and capacitor losses are negligible. Few have addressed the mid-range coils, seen in the majority of small-animal applications, where all the sources of loss are important, for example, mouse brain and body coils from 125 to 750 MHz. We developed a four-saddle coil array for magnetic resonance imaging of small animals. The saddle coil elements in the array were evenly distributed to cover the rat's head. The coil array was tuned to the resonant frequency of 170 MHz. Due to the close proximity of the coil elements, it was necessary to decouple the coil array using nonmagnetic trimmers and, it was operated in the transceiver mode and quadrature-driven. To test the coil array performance at high field, phantom images were acquired with our saddle coil array and standard pulse sequences on a research-dedicated 4 Tesla scanner. Ex vivo brain images of a rat were also acquired, and proved the feasibility of the scaled version of a saddle coil array and, its compatibility with standard pulse sequences when used in a high field magnetic resonance imager.

  12. The use of the multiple-gradient array for geoelectrical resistivity and induced polarization imaging

    NASA Astrophysics Data System (ADS)

    Aizebeokhai, Ahzegbobor P.; Oyeyemi, Kehinde D.

    2014-12-01

    The use of most conventional electrode configurations in electrical resistivity survey is often time consuming and labour intensive, especially when using manual data acquisition systems. Often, data acquisition teams tend to reduce data density so as to speed up field operation thereby reducing the survey cost; but this could significantly degrade the quality and resolution of the inverse models. In the present work, the potential of using the multiple-gradient array, a non-conventional electrode configuration, for practical cost effective and rapid subsurface resistivity and induced polarization mapping was evaluated. The array was used to conduct 2D resistivity and time-domain induced polarization imaging along two traverses in a study site at Ota, southwestern Nigeria. The subsurface was characterised and the main aquifer delineated using the inverse resistivity and chargeability images obtained. The performance of the multiple-gradient array was evaluated by correlating the 2D resistivity and chargeability images with those of the conventional Wenner array as well as the result of some soundings conducted along the same traverses using Schlumberger array. The multiple-gradient array has been found to have the advantage of measurement logistics and improved image resolution over the Wenner array.

  13. Noninvasive imaging using an array of electric potential sensors

    NASA Astrophysics Data System (ADS)

    Gebrial, W.; Prance, R. J.; Harland, C. J.; Clark, T. D.

    2006-06-01

    We present a design for a linear array of eight electric potential sensors arranged with 1mm spacing and configured to measure spatially varying potential at the microscopic scale. The array successfully detects a 50μm wide feature associated with one of the samples tested. In a single sensor arrangement we have demonstrated <1μm resolution, but the data acquisition times can become prohibitive. The sensors operate noninvasively by capacitively coupling to the sample. The issues associated with using an array of sensors in close proximity are addressed. Cross coupling and strategies for matching the response of the sensors are described in detail. Results are presented for a range of samples including a resistive potential divider, a ceramic microwave circuit board, and a section taken from an oil drill pipe containing a known fault. The data acquisition times are compared with those of a single sensor system, with improvements of 4.5 times in speed reported. In one case real-time simultaneous data acquisition is demonstrated using all eight sensors. Since these sensors operate via the displacement current they may also be applied to the characterization of material properties, including, for example, insulators, dielectrics, and poorly conducting composite materials. It is concluded that we see significant improvements in the data acquisition times for the linear array over a single sensor as expected and are able to overcome the difficulties associated with operating an array of sensors in close proximity.

  14. Noninvasive imaging using an array of electric potential sensors

    SciTech Connect

    Gebrial, W.; Prance, R. J.; Harland, C. J.; Clark, T. D.

    2006-06-15

    We present a design for a linear array of eight electric potential sensors arranged with 1 mm spacing and configured to measure spatially varying potential at the microscopic scale. The array successfully detects a 50 {mu}m wide feature associated with one of the samples tested. In a single sensor arrangement we have demonstrated <1 {mu}m resolution, but the data acquisition times can become prohibitive. The sensors operate noninvasively by capacitively coupling to the sample. The issues associated with using an array of sensors in close proximity are addressed. Cross coupling and strategies for matching the response of the sensors are described in detail. Results are presented for a range of samples including a resistive potential divider, a ceramic microwave circuit board, and a section taken from an oil drill pipe containing a known fault. The data acquisition times are compared with those of a single sensor system, with improvements of 4.5 times in speed reported. In one case real-time simultaneous data acquisition is demonstrated using all eight sensors. Since these sensors operate via the displacement current they may also be applied to the characterization of material properties, including, for example, insulators, dielectrics, and poorly conducting composite materials. It is concluded that we see significant improvements in the data acquisition times for the linear array over a single sensor as expected and are able to overcome the difficulties associated with operating an array of sensors in close proximity.

  15. Development of portable phased array UT system for real-time flaw imaging

    SciTech Connect

    Goto, M.

    1995-08-01

    Many functions and features of phased array UT technology must be useful for NDE in the industrial field. Some phased array UT systems have been developed for the inspection of nuclear pressure vessel and turbine components. However, phased array UT is still a special NDE technique and it has not been used widely in the past. The reasons of that are system size, cost, operator performance, equipment design and others. TOSHIBA has newly developed PC controlled portable phased array system to solve those problems. The portable phased array UT system is very compact and light but it is able to drive up to 32-channel linear array probe, to display real-time linear/sector B-scan, to display accumulated B-scan with an encoder and to display profile overlaid B-scan. The first applications were turbine component inspections for precise flaw investigation and flaw image data recording.

  16. Echo decorrelation imaging of ex vivo HIFU and bulk ultrasound ablation using image-treat arrays

    NASA Astrophysics Data System (ADS)

    Fosnight, Tyler R.; Hooi, Fong Ming; Colbert, Sadie B.; Keil, Ryan D.; Barthe, Peter G.; Mast, T. Douglas

    2017-03-01

    In this study, the ability of ultrasound echo decorrelation imaging to map and predict heat-induced cell death was tested using bulk ultrasound thermal ablation, high intensity focused ultrasound (HIFU) thermal ablation, and pulse-echo imaging of ex vivo liver tissue by a custom image-treat array. Tissue was sonicated at 5.0 MHz using either pulses of unfocused ultrasound (N=12) (7.5 s, 50.9-101.8 W/cm2 in situ spatial-peak, temporal-peak intensity) for bulk ablation or focused ultrasound (N=21) (1 s, 284-769 W/cm2 in situ spatial-peak, temporal-peak intensity and focus depth of 10 mm) for HIFU ablation. Echo decorrelation and integrated backscatter (IBS) maps were formed from radiofrequency pulse-echo images captured at 118 frames per second during 5.0 s rest periods, beginning 1.1 s after each sonication pulse. Tissue samples were frozen at -80˚C, sectioned, vitally stained, imaged, and semi-automatically segmented for receiver operating characteristic (ROC) analysis. ROC curves were constructed to assess prediction performance for echo decorrelation and IBS. Logarithmically scaled mean echo decorrelation in non-ablated and ablated tissue regions before and after electronic noise and motion correction were compared. Ablation prediction by echo decorrelation and IBS was significant for both focused and bulk ultrasound ablation. The log10-scaled mean echo decorrelation was significantly greater in regions of ablation for both HIFU and bulk ultrasound ablation. Echo decorrelation due to electronic noise and motion was significantly reduced by correction. These results suggest that ultrasound echo decorrelation imaging is a promising approach for real-time prediction of heat-induced cell death for guidance and monitoring of clinical thermal ablation, including radiofrequency ablation and HIFU.

  17. Designing of sparse 2D arrays for Lamb wave imaging using coarray concept

    SciTech Connect

    Ambroziński, Łukasz Stepinski, Tadeusz Uhl, Tadeusz

    2015-03-31

    2D ultrasonic arrays have considerable application potential in Lamb wave based SHM systems, since they enable equivocal damage imaging and even in some cases wave-mode selection. Recently, it has been shown that the 2D arrays can be used in SHM applications in a synthetic focusing (SF) mode, which is much more effective than the classical phase array mode commonly used in NDT. The SF mode assumes a single element excitation of subsequent transmitters and off-line processing the acquired data. In the simplest implementation of the technique, only single multiplexed input and output channels are required, which results in significant hardware simplification. Application of the SF mode for 2D arrays creates additional degrees of freedom during the design of the array topology, which complicates the array design process, however, it enables sparse array designs with performance similar to that of the fully populated dense arrays. In this paper we present the coarray concept to facilitate synthesis process of an array’s aperture used in the multistatic synthetic focusing approach in Lamb waves-based imaging systems. In the coherent imaging, performed in the transmit/receive mode, the sum coarray is a morphological convolution of the transmit/receive sub-arrays. It can be calculated as the set of sums of the individual sub-arrays’ elements locations. The coarray framework will be presented here using a an example of a star-shaped array. The approach will be discussed in terms of beampatterns of the resulting imaging systems. Both simulated and experimental results will be included.

  18. A comparison of imaging methods for use in an array biosensor.

    PubMed

    Golden, Joel P; Ligler, Frances S

    2002-09-01

    An array biosensor has been developed which uses an actively-cooled, charge-coupled device (CCD) imager. In an effort to save money and space, a complementary metal-oxide semiconductor (CMOS) camera and photodiode were tested as replacements for the cooled CCD imager. Different concentrations of CY5 fluorescent dye in glycerol were imaged using the three different detection systems with the same imaging optics. Signal discrimination above noise was compared for each of the three systems.

  19. A comparison of imaging methods for use in an array biosensor

    NASA Technical Reports Server (NTRS)

    Golden, Joel P.; Ligler, Frances S.

    2002-01-01

    An array biosensor has been developed which uses an actively-cooled, charge-coupled device (CCD) imager. In an effort to save money and space, a complementary metal-oxide semiconductor (CMOS) camera and photodiode were tested as replacements for the cooled CCD imager. Different concentrations of CY5 fluorescent dye in glycerol were imaged using the three different detection systems with the same imaging optics. Signal discrimination above noise was compared for each of the three systems.

  20. Highly Ordered Vertical Arrays of TiO2/ZnO Hybrid Nanowires: Synthesis and Electrochemical Characterization.

    PubMed

    Gujarati, Tanvi P; Ashish, Ajithan G; Rai, Maniratnam; Shaijumon, Manikoth M

    2015-08-01

    We report the fabrication of vertically aligned hierarchical arrays of TiO2/ZnO hybrid nanowires, consisting of ZnO nanowires grown directly from within the pores of TiO2 nanotubes, through a combination of electrochemical anodization and hydrothermal techniques. These novel nano-architectured hybrid nanowires with its unique properties show promise as high performance supercapacitor electrodes. The electrochemical behaviour of these hybrid nanowires has been studied using Cyclic voltammetry, Galvanostatic charge-discharge and Electrochemical impedance spectroscopy (EIS) measurements using 1.5 M tetraethylammoniumtetrafluoroborate in acetonitrile as the electrolyte. Excellent electrochemical performances with a maximum specific capacitance of 2.6 mF cm-2 at a current density of 10 µA cm-2, along with exceptional cyclic stability, have been obtained for TiO2/ZnO-1 h hybrid material. The obtained results demonstrate the possibility of fabricating new geometrical architectures of inorganic hybrid nanowires with well adhered interfaces for the development of hybrid energy devices.

  1. Correlation-based imaging technique using ultrasonic transmit-receive array for Non-Destructive Evaluation.

    PubMed

    Quaegebeur, Nicolas; Masson, Patrice

    2012-12-01

    This paper describes a novel array post-processing method for Non-Destructive Evaluation (NDE) using phased-array ultrasonic probes. The approach uses the capture and processing of the full matrix of all transmit-receive time-domain signals from a transducer array as in the case of the Total Focusing Method (TFM), referred as the standard of imaging algorithms. The proposed technique is based on correlation of measured signals with theoretical propagated signals computed over a given grid of points. In that case, real-time imaging can be simply implemented using discrete signal product. The advantage of the present technique is to take into account transducer directivity, dynamics and complex propagation patterns, such that the number of required array elements for a given imaging performance can be greatly reduced. Numerical and experimental application to contact inspection of isotropic structure is presented and real-time implementation issues are discussed.

  2. Delta-Doped Back-Illuminated CMOS Imaging Arrays: Progress and Prospects

    NASA Technical Reports Server (NTRS)

    Hoenk, Michael E.; Jones, Todd J.; Dickie, Matthew R.; Greer, Frank; Cunningham, Thomas J.; Blazejewski, Edward; Nikzad, Shouleh

    2009-01-01

    In this paper, we report the latest results on our development of delta-doped, thinned, back-illuminated CMOS imaging arrays. As with charge-coupled devices, thinning and back-illumination are essential to the development of high performance CMOS imaging arrays. Problems with back surface passivation have emerged as critical to the prospects for incorporating CMOS imaging arrays into high performance scientific instruments, just as they did for CCDs over twenty years ago. In the early 1990's, JPL developed delta-doped CCDs, in which low temperature molecular beam epitaxy was used to form an ideal passivation layer on the silicon back surface. Comprising only a few nanometers of highly-doped epitaxial silicon, delta-doping achieves the stability and uniformity that are essential for high performance imaging and spectroscopy. Delta-doped CCDs were shown to have high, stable, and uniform quantum efficiency across the entire spectral range from the extreme ultraviolet through the near infrared. JPL has recently bump-bonded thinned, delta-doped CMOS imaging arrays to a CMOS readout, and demonstrated imaging. Delta-doped CMOS devices exhibit the high quantum efficiency that has become the standard for scientific-grade CCDs. Together with new circuit designs for low-noise readout currently under development, delta-doping expands the potential scientific applications of CMOS imaging arrays, and brings within reach important new capabilities, such as fast, high-sensitivity imaging with parallel readout and real-time signal processing. It remains to demonstrate manufacturability of delta-doped CMOS imaging arrays. To that end, JPL has acquired a new silicon MBE and ancillary equipment for delta-doping wafers up to 200mm in diameter, and is now developing processes for high-throughput, high yield delta-doping of fully-processed wafers with CCD and CMOS imaging devices.

  3. Semantic network array processor and its applications to image understanding

    SciTech Connect

    Dixit, V.; Moldovan, D.I.

    1987-01-01

    The problems in computer vision range from edge detection and segmentation at the lowest level to the problem of cognition at the highest level. This correspondence describes the organization and operation of a semantic network array processor (SNAP) as applicable to high level computer vision problems. The architecture consists of an array of identical cells each containing a content addressable memory, microprogram control, and a communication unit. The applications discussed in this paper are the two general techniques, discrete relaxation and dynamic programming. While the discrete relaxation is discussed with reference to scene labeling and edge interpretation, the dynamic programming is tuned for stereo.

  4. An Improved Solution for Integrated Array Optics in Quasi-Optical mm and Submm Receivers: the Hybrid Antenna

    NASA Technical Reports Server (NTRS)

    Buttgenbach, Thomas H.

    1993-01-01

    The hybrid antenna discussed here is defined as a dielectric lens-antenna as a special case of an extended hemi-spherical dielectric lens that is operated in the diffraction limited regime. It is a modified version of the planar antenna on a lens scheme developed by Rutledge. The dielectric lens-antenna is fed by a planar-structure antenna, which is mounted on the flat side of the dielectric lens-antenna using it as a substrate, and the combination is termed a hybrid antenna. Beam pattern and aperture efficiency measurements were made at millimeter and submillimeter wavelengths as a function of extension of the hemi- spherical lens and different lens sizes. An optimum extension distance is found experimentally and numerically for which excellent beam patterns and simultaneously high aperture efficiencies can be achieved. At 115 GHz the aperture efficiency was measured to be (76 4 +/- 6) % for a diffraction limited beam with sidelobes below -17 dB. Results of a single hybrid antenna with an integrated Superconductor-Insulator-Superconductor (SIS) detector and a broad-band matching structure at submillimeter wavelengths are presented. The hybrid antenna is diffraction limited, space efficient in an array due to its high aperture efficiency, and is easily mass produced, thus being well suited for focal plane heterodyne receiver arrays.

  5. Carbon fiber/Co9S8 nanotube arrays hybrid structures for flexible quantum dot-sensitized solar cells.

    PubMed

    Guo, Wenxi; Chen, Chang; Ye, Meidan; Lv, Miaoqiang; Lin, Changjian

    2014-04-07

    Recently, hybrid carbon materials and inorganic nanocrystals have received an intensive amount of attention and have opened up an exciting new field in the design and fabrication of high-performance catalysts. Here we present a novel kind of hybrid counter electrode (CE) consisting of a carbon fiber (CF) and Co9S8 nanotube arrays (NTs) for fiber-shaped flexible quantum dot-sensitized solar cells (QDSSCs). The growth mechanisms of Co(CO3)0.35Cl0.20(OH)1.10 nanowire arrays (NWs) on the CFs were discussed, and the catalytic activity of the CF, Pt and Co9S8/CF hybrid structure (Co9S8@CF) were elucidated systematically as well. An absolute energy conversion efficiency of 3.79% has been demonstrated under 100 mW cm(-2) AM 1.5 illumination by using Co9S8@CF as a CE. This work not only demonstrates an innovative approach for growing cobalt sulfide NTs on flexible substrates that can be applied in flexible devices for energy harvesting and storage, but also provides a kind of hybrid structure and high-efficiency CE for QDSSCs.

  6. Detection of pathogenic E. coli O157:H7 by a hybrid microfluidic SPR and molecular imaging cytometry device.

    PubMed

    Zordan, Michael D; Grafton, Meggie M G; Acharya, Ghanashyam; Reece, Lisa M; Cooper, Christy L; Aronson, Arthur I; Park, Kinam; Leary, James F

    2009-02-01

    Current methods to screen for bacterial contamination involve using costly reagents such as antibodies or PCR reagents or time-costly growth in cultures. There is need for portable, real-time, multiplex pathogen detection technology that can predict the safety of food. Surface plasmon resonance (SPR) imaging is a sensitive, label-free method that can detect the binding of an analyte to a surface by the changes in refractive index that occur upon binding. We have designed a hybrid microfluidic biochip to perform multiplexed detection of single-celled pathogens using a combination of SPR and fluorescence imaging. The device consists of an array of gold spots, each functionalized with a capture biomolecule targeting a specific pathogen. This biosensor array is enclosed by a polydimethylsiloxane microfluidic flow chamber that delivers a magnetically concentrated sample to be tested. The sample is imaged by SPR on the bottom of the biochip and epi-fluorescence on the top. The prototype instrument was successfully able to image antibody-captured E. coli O157:H7 bacteria by SPR and fluorescence imaging. The efficiency of capture of these bacteria by the magnetic particles was determined using spectrophotometric ferric oxide absorbance measurements. The binding of the E. coli to each spot was quantified by measuring the percent of the gold spot area upon which the bacteria was bound and analyzed using NIH ImageJ software. This hybrid imaging approach of pathogenic E. coli detection coupled with an estimate of relative infectivity is shown to be a working example of a testing device for potential foodborne pathogens.

  7. Hybrid regularizers-based adaptive anisotropic diffusion for image denoising.

    PubMed

    Liu, Kui; Tan, Jieqing; Ai, Liefu

    2016-01-01

    To eliminate the staircasing effect for total variation filter and synchronously avoid the edges blurring for fourth-order PDE filter, a hybrid regularizers-based adaptive anisotropic diffusion is proposed for image denoising. In the proposed model, the [Formula: see text]-norm is considered as the fidelity term and the regularization term is composed of a total variation regularization and a fourth-order filter. The two filters can be adaptively selected according to the diffusion function. When the pixels locate at the edges, the total variation filter is selected to filter the image, which can preserve the edges. When the pixels belong to the flat regions, the fourth-order filter is adopted to smooth the image, which can eliminate the staircase artifacts. In addition, the split Bregman and relaxation approach are employed in our numerical algorithm to speed up the computation. Experimental results demonstrate that our proposed model outperforms the state-of-the-art models cited in the paper in both the qualitative and quantitative evaluations.

  8. A hybrid framework for 3D medical image segmentation.

    PubMed

    Chen, Ting; Metaxas, Dimitris

    2005-12-01

    In this paper we propose a novel hybrid 3D segmentation framework which combines Gibbs models, marching cubes and deformable models. In the framework, first we construct a new Gibbs model whose energy function is defined on a high order clique system. The new model includes both region and boundary information during segmentation. Next we improve the original marching cubes method to construct 3D meshes from Gibbs models' output. The 3D mesh serves as the initial geometry of the deformable model. Then we deform the deformable model using external image forces so that the model converges to the object surface. We run the Gibbs model and the deformable model recursively by updating the Gibbs model's parameters using the region and boundary information in the deformable model segmentation result. In our approach, the hybrid combination of region-based methods and boundary-based methods results in improved segmentations of complex structures. The benefit of the methodology is that it produces high quality segmentations of 3D structures using little prior information and minimal user intervention. The modules in this segmentation methodology are developed within the context of the Insight ToolKit (ITK). We present experimental segmentation results of brain tumors and evaluate our method by comparing experimental results with expert manual segmentations. The evaluation results show that the methodology achieves high quality segmentation results with computational efficiency. We also present segmentation results of other clinical objects to illustrate the strength of the methodology as a generic segmentation framework.

  9. Facile construction of vertically aligned EuS-ZnO hybrid core shell nanorod arrays for visible light driven photocatalytic properties

    SciTech Connect

    Ranjith, K. S.; Kumar, D. Ranjith; Kumar, R. T. Rajendra

    2015-06-24

    We demonstrated the development of coupled semiconductor in the form of hybrid heterostructures for significant advancement in catalytic functional materials. In this article, we report the preparation of vertically aligned core shell ZnO-EuS nanorod photocatalyst arrays by a simple chemical solution process followed by sulfudation process. The XRD pattern confirmed formation of the hexagonal wurtzite structure of ZnO and cubic nature of the EuS. Cross sectional FESEM images show vertical rod array structure, and the size of the nanorods ranges from 80 to 120 nm. UV-Vis DRS spectra showed that the optical absorption of ZnO was significantly enhanced to the visible region by modification with EuS surfaces. TEM study confirmed that the surface of ZnO was drastically improved by the modification with EuS nanoparticle. The catalytic activity of EuS−ZnO core shell nanorod arrays were evaluated by the photodegradation of Methylene Blue (MB) dye under visible irradiation. The results revealed that the photocatalytic activity of EuS−ZnO was much higher than that of ZnO under natural sunlight. EuS−ZnO was found to be stable and reusable without appreciable loss of catalytic activity up to four consecutive cycles.

  10. Measured responsivities of generation II and hybrid image intensifiers

    SciTech Connect

    Yates, G.J.; King, N.S.P.; Thomas, M.C.

    1995-07-01

    We have measured the absolute and coupled system responsivities of several image intensifier types at several wavelengths in the visible spectrum. Intensifiers characterized include microchannel plate (MCP) generation II proximity-focused and hybrid generation I/generation II electrostatic-focused designs. Configurations including single plate, double plate, nominal and high strip current MCPs, and standard S20 and super generation II enhanced S-20 photocathodes were evaluated. Absolute responsivity measurements were performed using NIST-traceable radiometry instrumentation. The normalized relative sensitivities and overall optical luminous gain performance provided by individual intensifiers when similarly coupled to either high resolution 10-bit RS-170 CCD or FPS cameras are presented along with their radiometric data.

  11. Application of Uncooled Monolithic Thermoelectric Linear Arrays to Imaging Radiometers

    NASA Astrophysics Data System (ADS)

    Kruse, Paul W.

    Introduction Identification of Incipient Failure of Railcar Wheels Technical Description of the Model IR 1000 Imaging Radiometer Performance of the Model IR 1000 Imaging Radiometer Initial Application Summary Imaging Radiometer for Predictive and Preventive Maintenance Description Operation Specifications Summary References INDEX CONTENTS OF VOLUMES IN THIS SERIES

  12. Superconducting Microwave Resonator Arrays for Submillimeter/Far-Infrared Imaging

    NASA Astrophysics Data System (ADS)

    Noroozian, Omid

    Superconducting microwave resonators have the potential to revolutionize submillimeter and far-infrared astronomy, and with it our understanding of the universe. The field of low-temperature detector technology has reached a point where extremely sensitive devices like transition-edge sensors are now capable of detecting radiation limited by the background noise of the universe. However, the size of these detector arrays are limited to only a few thousand pixels. This is because of the cost and complexity of fabricating large-scale arrays of these detectors that can reach up to 10 lithographic levels on chip, and the complicated SQUID-based multiplexing circuitry and wiring for readout of each detector. In order to make substantial progress, next-generation ground-based telescopes such as CCAT or future space telescopes require focal planes with large-scale detector arrays of 104--10 6 pixels. Arrays using microwave kinetic inductance detectors (MKID) are a potential solution. These arrays can be easily made with a single layer of superconducting metal film deposited on a silicon substrate and pattered using conventional optical lithography. Furthermore, MKIDs are inherently multiplexable in the frequency domain, allowing ˜ 10 3 detectors to be read out using a single coaxial transmission line and cryogenic amplifier, drastically reducing cost and complexity. An MKID uses the change in the microwave surface impedance of a superconducting thin-film microresonator to detect photons. Absorption of photons in the superconductor breaks Cooper pairs into quasiparticles, changing the complex surface impedance, which results in a perturbation of resonator frequency and quality factor. For excitation and readout, the resonator is weakly coupled to a transmission line. The complex amplitude of a microwave probe signal tuned on-resonance and transmitted on the feedline past the resonator is perturbed as photons are absorbed in the superconductor. The perturbation can be

  13. Four-channel surface coil array for sequential CW-EPR image acquisition

    NASA Astrophysics Data System (ADS)

    Enomoto, Ayano; Emoto, Miho; Fujii, Hirotada; Hirata, Hiroshi

    2013-09-01

    This article describes a four-channel surface coil array to increase the area of visualization for continuous-wave electron paramagnetic resonance (CW-EPR) imaging. A 776-MHz surface coil array was constructed with four independent surface coil resonators and three kinds of switches. Control circuits for switching the resonators were also built to sequentially perform EPR image acquisition for each resonator. The resonance frequencies of the resonators were shifted using PIN diode switches to decouple the inductively coupled coils. To investigate the area of visualization with the surface coil array, three-dimensional EPR imaging was performed using a glass cell phantom filled with a solution of nitroxyl radicals. The area of visualization obtained with the surface coil array was increased approximately 3.5-fold in comparison to that with a single surface coil resonator. Furthermore, to demonstrate the applicability of this surface coil array to animal imaging, three-dimensional EPR imaging was performed in a living mouse with an exogenously injected nitroxyl radical imaging agent.

  14. Closely-spaced double-row microstrip RF arrays for parallel MR imaging at ultrahigh fields

    PubMed Central

    Yan, Xinqiang; Xue, Rong; Zhang, Xiaoliang

    2015-01-01

    Radiofrequency (RF) coil arrays with high count of elements, e.g., closely-spaced multi-row arrays, exhibit superior parallel imaging performance in MRI. However, it is technically challenging and time-consuming to build multi-row arrays due to complex coupling issues. This paper presents a novel and simple method for closely-spaced multi-row RF array designs. Induced current elimination (ICE) decoupling method has shown the capability of reducing coupling between microstrip elements from different rows. In this study, its capability for decoupling array elements from the same row was investigated and validated by bench tests, with an isolation improvement from −8.9 dB to −20.7 dB. Based on this feature, a closely-spaced double-row microstrip array with 16 elements was built at 7T. S21 between any two elements of the 16-channel closely-spaced was better than −14 dB. In addition, its feasibility and performance was validated by MRI experiments. No significant image reconstruction- related noise amplifications were observed for parallel imaging even when reduced factor (R) achieves 4. The experimental results demonstrated that the proposed design might be a simple and efficient approach in fabricating closely-spaced multi-row RF arrays. PMID:26508810

  15. Closely-spaced double-row microstrip RF arrays for parallel MR imaging at ultrahigh fields.

    PubMed

    Yan, Xinqiang; Xue, Rong; Zhang, Xiaoliang

    2015-11-01

    Radiofrequency (RF) coil arrays with high count of elements, e.g., closely-spaced multi-row arrays, exhibit superior parallel imaging performance in MRI. However, it is technically challenging and time-consuming to build multi-row arrays due to complex coupling issues. This paper presents a novel and simple method for closely-spaced multi-row RF array designs. Induced current elimination (ICE) decoupling method has shown the capability of reducing coupling between microstrip elements from different rows. In this study, its capability for decoupling array elements from the same row was investigated and validated by bench tests, with an isolation improvement from -8.9 dB to -20.7 dB. Based on this feature, a closely-spaced double-row microstrip array with 16 elements was built at 7T. S21 between any two elements of the 16-channel closely-spaced was better than -14 dB. In addition, its feasibility and performance was validated by MRI experiments. No significant image reconstruction- related noise amplifications were observed for parallel imaging even when reduced factor (R) achieves 4. The experimental results demonstrated that the proposed design might be a simple and efficient approach in fabricating closely-spaced multi-row RF arrays.

  16. Large-Format AlGaN PIN Photodiode Arrays for UV Images

    NASA Technical Reports Server (NTRS)

    Aslam, Shahid; Franz, David

    2010-01-01

    A large-format hybridized AlGaN photodiode array with an adjustable bandwidth features stray-light control, ultralow dark-current noise to reduce cooling requirements, and much higher radiation tolerance than previous technologies. This technology reduces the size, mass, power, and cost of future ultraviolet (UV) detection instruments by using lightweight, low-voltage AlGaN detectors in a hybrid detector/multiplexer configuration. The solar-blind feature eliminates the need for additional visible light rejection and reduces the sensitivity of the system to stray light that can contaminate observations.

  17. Real-time B-scan ultrasonic imaging using a digital phased array system for NDE

    NASA Astrophysics Data System (ADS)

    Dunki-Jacobs, Robert; Thomas, Lewis

    A demonstration is presented of the ability to produce real-time images of metals on the basis of a phased-array ultrasound system. Attention is given to the critical role played by a beam-former. It is established that the present imaging system's resolution approaches the theoretical capabilities of the given aperture size and wavelength.

  18. Dual source and dual detector arrays tetrahedron beam computed tomography for image guided radiotherapy.

    PubMed

    Kim, Joshua; Lu, Weiguo; Zhang, Tiezhi

    2014-02-07

    Cone-beam computed tomography (CBCT) is an important online imaging modality for image guided radiotherapy. But suboptimal image quality and the lack of a real-time stereoscopic imaging function limit its implementation in advanced treatment techniques, such as online adaptive and 4D radiotherapy. Tetrahedron beam computed tomography (TBCT) is a novel online imaging modality designed to improve on the image quality provided by CBCT. TBCT geometry is flexible, and multiple detector and source arrays can be used for different applications. In this paper, we describe a novel dual source-dual detector TBCT system that is specially designed for LINAC radiation treatment machines. The imaging system is positioned in-line with the MV beam and is composed of two linear array x-ray sources mounted aside the electrical portal imaging device and two linear arrays of x-ray detectors mounted below the machine head. The detector and x-ray source arrays are orthogonal to each other, and each pair of source and detector arrays forms a tetrahedral volume. Four planer images can be obtained from different view angles at each gantry position at a frame rate as high as 20 frames per second. The overlapped regions provide a stereoscopic field of view of approximately 10-15 cm. With a half gantry rotation, a volumetric CT image can be reconstructed having a 45 cm field of view. Due to the scatter rejecting design of the TBCT geometry, the system can potentially produce high quality 2D and 3D images with less radiation exposure. The design of the dual source-dual detector system is described, and preliminary results of studies performed on numerical phantoms and simulated patient data are presented.

  19. Dual source and dual detector arrays tetrahedron beam computed tomography for image guided radiotherapy

    NASA Astrophysics Data System (ADS)

    Kim, Joshua; Lu, Weiguo; Zhang, Tiezhi

    2014-02-01

    Cone-beam computed tomography (CBCT) is an important online imaging modality for image guided radiotherapy. But suboptimal image quality and the lack of a real-time stereoscopic imaging function limit its implementation in advanced treatment techniques, such as online adaptive and 4D radiotherapy. Tetrahedron beam computed tomography (TBCT) is a novel online imaging modality designed to improve on the image quality provided by CBCT. TBCT geometry is flexible, and multiple detector and source arrays can be used for different applications. In this paper, we describe a novel dual source-dual detector TBCT system that is specially designed for LINAC radiation treatment machines. The imaging system is positioned in-line with the MV beam and is composed of two linear array x-ray sources mounted aside the electrical portal imaging device and two linear arrays of x-ray detectors mounted below the machine head. The detector and x-ray source arrays are orthogonal to each other, and each pair of source and detector arrays forms a tetrahedral volume. Four planer images can be obtained from different view angles at each gantry position at a frame rate as high as 20 frames per second. The overlapped regions provide a stereoscopic field of view of approximately 10-15 cm. With a half gantry rotation, a volumetric CT image can be reconstructed having a 45 cm field of view. Due to the scatter rejecting design of the TBCT geometry, the system can potentially produce high quality 2D and 3D images with less radiation exposure. The design of the dual source-dual detector system is described, and preliminary results of studies performed on numerical phantoms and simulated patient data are presented.

  20. Real-time, continuous-wave terahertz imaging using a microbolometer focal-plane array

    NASA Technical Reports Server (NTRS)

    Hu, Qing (Inventor); Min Lee, Alan W. (Inventor)

    2010-01-01

    The present invention generally provides a terahertz (THz) imaging system that includes a source for generating radiation (e.g., a quantum cascade laser) having one or more frequencies in a range of about 0.1 THz to about 10 THz, and a two-dimensional detector array comprising a plurality of radiation detecting elements that are capable of detecting radiation in that frequency range. An optical system directs radiation from the source to an object to be imaged. The detector array detects at least a portion of the radiation transmitted through the object (or reflected by the object) so as to form a THz image of that object.

  1. Characterization of copy number variation in genomic regions containing STR loci using array comparative genomic hybridization.

    PubMed

    Repnikova, Elena A; Rosenfeld, Jill A; Bailes, Andrea; Weber, Cecilia; Erdman, Linda; McKinney, Aimee; Ramsey, Sarah; Hashimoto, Sayaka; Lamb Thrush, Devon; Astbury, Caroline; Reshmi, Shalini C; Shaffer, Lisa G; Gastier-Foster, Julie M; Pyatt, Robert E

    2013-09-01

    Short tandem repeat (STR) loci are commonly used in forensic casework, familial analysis for human identification, and for monitoring hematopoietic cell engraftment after bone marrow transplant. Unexpected genetic variation leading to sequence and length differences in STR loci can complicate STR typing, and presents challenges in casework interpretation. Copy number variation (CNV) is a relatively recently identified form of genetic variation consisting of genomic regions present at variable copy numbers within an individual compared to a reference genome. Large scale population studies have demonstrated that likely all individuals carry multiple regions with CNV of 1kb in size or greater in their genome. To date, no study correlating genomic regions containing STR loci with CNV has been conducted. In this study, we analyzed results from 32,850 samples sent for clinical array comparative genomic hybridization (CGH) analysis for the presence of CNV at regions containing the 13 CODIS (Combined DNA Index System) STR, and the Amelogenin X (AMELX) and Amelogenin Y (AMELY) loci. Thirty-two individuals with CNV involving STR loci on chromosomes 2, 4, 7, 11, 12, 13, 16, and 21, and twelve with CNV involving the AMELX/AMELY loci were identified. These results were correlated with data from publicly available databases housing information on CNV identified in normal populations and additional clinical cases. These collective results demonstrate the presence of CNV in regions containing 9 of the 13 CODIS STR and AMELX/Y loci. Further characterization of STR profiles within regions of CNV, additional cataloging of these variants in multiple populations, and contributing such examples to the public domain will provide valuable information for reliable use of these loci.

  2. Array comparative genomic hybridization and cytogenetic analysis in pediatric acute leukemias.

    PubMed

    Dawson, A J; Yanofsky, R; Vallente, R; Bal, S; Schroedter, I; Liang, L; Mai, S

    2011-10-01

    Most patients with acute lymphocytic leukemia (all) are reported to have acquired chromosomal abnormalities in their leukemic bone marrow cells. Many established chromosome rearrangements have been described, and their associations with specific clinical, biologic, and prognostic features are well defined. However, approximately 30% of pediatric and 50% of adult patients with all do not have cytogenetic abnormalities of clinical significance. Despite significant improvements in outcome for pediatric all, therapy fails in approximately 25% of patients, and these failures often occur unpredictably in patients with a favorable prognosis and "good" cytogenetics at diagnosis.It is well known that karyotype analysis in hematologic malignancies, although genome-wide, is limited because of altered cell kinetics (mitotic rate), a propensity of leukemic blasts to undergo apoptosis in culture, overgrowth by normal cells, and chromosomes of poor quality in the abnormal clone. Array comparative genomic hybridization (acgh-"microarray") has a greatly increased genomic resolution over classical cytogenetics. Cytogenetic microarray, which uses genomic dna, is a powerful tool in the analysis of unbalanced chromosome rearrangements, such as copy number gains and losses, and it is the method of choice when the mitotic index is low and the quality of metaphases is suboptimal. The copy number profile obtained by microarray is often called a "molecular karyotype."In the present study, microarray was applied to 9 retrospective cases of pediatric all either with initial high-risk features or with at least 1 relapse. The conventional karyotype was compared to the "molecular karyotype" to assess abnormalities as interpreted by classical cytogenetics. Not only were previously undetected chromosome losses and gains identified by microarray, but several karyotypes interpreted by classical cytogenetics were shown to be discordant with the microarray results. The complementary use of microarray

  3. A 32-Channel Combined RF and B0 Shim Array for 3T Brain Imaging

    PubMed Central

    Stockmann, Jason P.; Witzel, Thomas; Keil, Boris; Polimeni, Jonathan R.; Mareyam, Azma; LaPierre, Cristen; Setsompop, Kawin; Wald, Lawrence L.

    2016-01-01

    Purpose We add user-controllable direct currents (DC) to the individual elements of a 32-channel radio-frequency (RF) receive array to provide B0 shimming ability while preserving the array’s reception sensitivity and parallel imaging performance. Methods Shim performance using constrained DC current (±2.5A) is simulated for brain arrays ranging from 8 to 128 elements. A 32-channel 3-tesla brain array is realized using inductive chokes to bridge the tuning capacitors on each RF loop. The RF and B0 shimming performance is assessed in bench and imaging measurements. Results The addition of DC currents to the 32-channel RF array is achieved with minimal disruption of the RF performance and/or negative side effects such as conductor heating or mechanical torques. The shimming results agree well with simulations and show performance superior to third-order spherical harmonic (SH) shimming. Imaging tests show the ability to reduce the standard frontal lobe susceptibility-induced fields and improve echo planar imaging geometric distortion. The simulation of 64- and 128-channel brain arrays suggest that even further shimming improvement is possible (equivalent to up to 6th-order SH shim coils). Conclusion Including user-controlled shim currents on the loops of a conventional highly parallel brain array coil is feasible with modest current levels and produces improved B0 shimming performance over standard second-order SH shimming. PMID:25689977

  4. Development of thin-film flat-panel arrays for diagnostic and radiotherapy imaging

    NASA Astrophysics Data System (ADS)

    Antonuk, Larry E.; Boudry, John M.; Yorkston, John; Morton, E. J.; Huang, Weidong; Street, Robert A.

    1992-06-01

    Since the design and fabrication of the first pixelated, two-dimensional, hydrogenated amorphous silicon image sensor arrays at Xerox, PARC, in 1988, a variety of milestones have been achieved including the first demonstration of high quality radiographic images of low- contrast, anatomical detail. Current array configurations and design rules offer the prospect of 100 micrometers pixel pitches over 30 by 30 cm2 areas in the next few years. Beyond this, present attempts to extend the size of the substrates to 100 cm on the diagonal by 1996 coupled with the possibility of three-dimensional thin-film electronics could eventually result in a revolution in many forms of x-ray imaging. Such arrays will present challenges in the design of the fast, analog, and digital electronic readout systems required to precisely match the characteristics of the arrays to those of the imaging needs. For such arrays, one of the most important parameters is the dynamic range. Early results are reported for the measured limits on this quantity as obtained through measurements from individual sensors and FETs as well as an improved lower limit as obtained by direct measurements of array pixels.

  5. Hybrid Imaging for Extended Depth of Field Microscopy

    NASA Astrophysics Data System (ADS)

    Zahreddine, Ramzi Nicholas

    An inverse relationship exists in optical systems between the depth of field (DOF) and the minimum resolvable feature size. This trade-off is especially detrimental in high numerical aperture microscopy systems where resolution is pushed to the diffraction limit resulting in a DOF on the order of 500 nm. Many biological structures and processes of interest span over micron scales resulting in significant blurring during imaging. This thesis explores a two-step computational imaging technique known as hybrid imaging to create extended DOF (EDF) microscopy systems with minimal sacrifice in resolution. In the first step a mask is inserted at the pupil plane of the microscope to create a focus invariant system over 10 times the traditional DOF, albeit with reduced contrast. In the second step the contrast is restored via deconvolution. Several EDF pupil masks from the literature are quantitatively compared in the context of biological microscopy. From this analysis a new mask is proposed, the incoherently partitioned pupil with binary phase modulation (IPP-BPM), that combines the most advantageous properties from the literature. Total variation regularized deconvolution models are derived for the various noise conditions and detectors commonly used in biological microscopy. State of the art algorithms for efficiently solving the deconvolution problem are analyzed for speed, accuracy, and ease of use. The IPP-BPM mask is compared with the literature and shown to have the highest signal-to-noise ratio and lowest mean square error post-processing. A prototype of the IPP-BPM mask is fabricated using a combination of 3D femtosecond glass etching and standard lithography techniques. The mask is compared against theory and demonstrated in biological imaging applications.

  6. The Non-Imaging CHErenkov (NICHE) Array: A TA/TALE extension using Cherenkov radiation to measure Cosmic Ray Composition to sub-PeV energies

    NASA Astrophysics Data System (ADS)

    Krizmanic, John; Bergman, Douglas; Tsunesada, Yoshiki; Abu-Zayyad, Tareq; Belz, John; Thomson, Gordon

    2017-01-01

    Co-sited with the Telescope Array (TA) Low Energy (TALE) extension, the Non-Imaging CHErenkov (NICHE) Array will measure the flux and nuclear composition evolution of cosmic rays (CRs) from below 1 PeV to 1 EeV in its eventual full deployment. NICHE will co-measure CR air showers with TA/TALE and will initially be deployed to observe events simultaneously with the TALE telescopes acting in imaging-Cherenkov mode, providing the first hybrid-Cherenkov (simultaneous imaging and non-imaging Cherenkov) measurements of CRs in the Knee region of the CR energy spectrum. NICHE uses easily deployable detectors to measure the amplitude and time-spread of the air-shower Cherenkov signal to achieve an event-by-event measurement of Xmax and energy, each with excellent resolution. First generation detectors are under construction and will form an initial prototype array (jNICHE) that will be deployed in early 2017 at the TA/TALE site. In this talk, the NICHE design, array performance, jNICHE development, and status will be discussed as well as NICHE's ability to measure the cosmic ray nuclear composition as a function of energy.

  7. Characteristics of stereo images from detectors in focal plane array.

    PubMed

    Son, Jung-Young; Yeom, Seokwon; Chun, Joo-Hwan; Guschin, Vladmir P; Lee, Dong-Su

    2011-07-01

    The equivalent ray geometry of two horizontally aligned detectors at the focal plane of the main antenna in a millimeter wave imaging system is analyzed to reveal the reason why the images from the detectors are fused as an image with a depth sense. Scanning the main antenna in both horizontal and vertical directions makes each detector perform as a camera, and the two detectors can work like a stereo camera in the millimeter wave range. However, the stereo camera geometry is different from that of the stereo camera used in the visual spectral range because the detectors' viewing directions are diverging to each other and they are a certain distance apart. The depth sense is mainly induced by the distance between detectors. The images obtained from the detectors in the millimeter imaging system are perceived with a good depth sense. The disparities responsible for the depth sense are identified in the images.

  8. Dual-Enzyme-Loaded Multifunctional Hybrid Nanogel System for Pathological Responsive Ultrasound Imaging and T2-Weighted Magnetic Resonance Imaging.

    PubMed

    Wang, Xia; Niu, Dechao; Li, Pei; Wu, Qing; Bo, Xiaowan; Liu, Boji; Bao, Song; Su, Teng; Xu, Huixiong; Wang, Qigang

    2015-06-23

    A dual-enzyme-loaded multifunctional hybrid nanogel probe (SPIO@GCS/acryl/biotin-CAT/SOD-gel, or SGC) has been developed for dual-modality pathological responsive ultrasound (US) imaging and enhanced T2-weighted magnetic resonance (MR) imaging. This probe is composed of functionalized superparamagnetic iron oxide particles, a dual enzyme species (catalase and superoxide dismutase), and a polysaccharide cationic polymer glycol chitosan gel. The dual-modality US/MR imaging capabilities of the hybrid nanogel for responsive US imaging and enhanced T2-weighted MR imaging have been evaluated both in vitro and in vivo. These results show that the hybrid nanogel SGC can exhibit efficient dual-enzyme biocatalysis with pathological species for responsive US imaging. SGC also demonstrates increased accumulation in acidic environments for enhanced T2-weighted MR imaging. Further research on these nanogel systems may lead to the development of more efficient US/MR contrast agents.

  9. Photoacoustic imaging of the human forearm using 40 MHz linear-array transducer

    NASA Astrophysics Data System (ADS)

    Zafar, Haroon; Breathnach, Aedán.; Subhash, Hrebesh M.; Leahy, Martin J.

    2014-02-01

    In this work photoacoustic imaging (PAI) based on multi element linear-array transducer, combined with multichannel collecting system was used for in vivo imaging of microcirculation of the human forearm. The Vevo® 2100 LAZR PAT system (VISUALSONICS) was used for imaging which simultaneously collects high-resolution ultrasound and photoacoustic signals. 3D PA and high frequency ultrasound scans, measured 30.5 mm (length) x 14.1 mm (width) x 10 mm (depth) were acquired from the area of forearm skin using 40 MHz frequency transducer at 860 nm wavelength. 3D structural and functional (microcirculation) maps of the forearm skin were obtained. The multi element linear-array transducer based PAI has been found promising in terms of resolution, imaging depth and imaging speed for in vivo microcirculation imaging within human skin.

  10. An abuttable CCD imager for visible and X-ray focal plane arrays

    NASA Technical Reports Server (NTRS)

    Burke, Barry E.; Mountain, Robert W.; Harrison, David C.; Bautz, Marshall W.; Doty, John P.

    1991-01-01

    A frame-transfer silicon charge-coupled-device (CCD) imager has been developed that can be closely abutted to other imagers on three sides of the imaging array. It is intended for use in multichip arrays. The device has 420 x 420 pixels in the imaging and frame-store regions and is constructed using a three-phase triple-polysilicon process. Particular emphasis has been placed on achieving low-noise charge detection for low-light-level imaging in the visible and maximum energy resolution for X-ray spectroscopic applications. Noise levels of 6 electrons at 1-MHz and less than 3 electrons at 100-kHz data rates have been achieved. Imagers have been fabricated on 1000-Ohm-cm material to maximize quantum efficiency and minimize split events in the soft X-ray regime.

  11. Coherent-weighted three-dimensional image reconstruction in linear-array-based photoacoustic tomography.

    PubMed

    Wang, Depeng; Wang, Yuehang; Zhou, Yang; Lovell, Jonathan F; Xia, Jun

    2016-05-01

    While the majority of photoacoustic imaging systems used custom-made transducer arrays, commercially-available linear transducer arrays hold the benefits of affordable price, handheld convenience and wide clinical recognition. They are not widely used in photoacoustic imaging primarily because of the poor elevation resolution. Here, without modifying the imaging geometry and system, we propose addressing this limitation purely through image reconstruction. Our approach is based on the integration of two advanced image reconstruction techniques: focal-line-based three-dimensional image reconstruction and coherent weighting. We first numerically validated our approach through simulation and then experimentally tested it in phantom and in vivo. Both simulation and experimental results proved that the method can significantly improve the elevation resolution (up to 4 times in our experiment) and enhance object contrast.

  12. Coherent-weighted three-dimensional image reconstruction in linear-array-based photoacoustic tomography

    PubMed Central

    Wang, Depeng; Wang, Yuehang; Zhou, Yang; Lovell, Jonathan F.; Xia, Jun

    2016-01-01

    While the majority of photoacoustic imaging systems used custom-made transducer arrays, commercially-available linear transducer arrays hold the benefits of affordable price, handheld convenience and wide clinical recognition. They are not widely used in photoacoustic imaging primarily because of the poor elevation resolution. Here, without modifying the imaging geometry and system, we propose addressing this limitation purely through image reconstruction. Our approach is based on the integration of two advanced image reconstruction techniques: focal-line-based three-dimensional image reconstruction and coherent weighting. We first numerically validated our approach through simulation and then experimentally tested it in phantom and in vivo. Both simulation and experimental results proved that the method can significantly improve the elevation resolution (up to 4 times in our experiment) and enhance object contrast. PMID:27231634

  13. 64-line-sensor array: fast imaging system for photoacoustic tomography

    NASA Astrophysics Data System (ADS)

    Gratt, Sibylle; Nuster, Robert; Wurzinger, Gerhild; Bugl, Markus; Paltauf, Guenther

    2014-03-01

    Three-dimensional photoacoustic tomography with line sensors, which integrate the pressure along their length, has shown to produce accurate images of small animals. To reduce the scanning time and to enable in vivo applications, a detection array is built consisting of 64 piezoelectric line sensors which are arranged on a semi-cylinder. When measuring line integrated pressure signals around the imaging object, the three-dimensional photoacoustic imaging problem is reduced to a set of two-dimensional reconstructions and the measurement setup requires only a single axis of rotation. The shape and size of the array were adapted to the given problem of biomedical imaging and small animal imaging in particular. The length and width of individual line elements had to be chosen in order to take advantage of the favorable line integrating properties, maintaining the requested resolution of the image. For data acquisition the signals from the 64 elements are amplified and multiplexed into a 32 channel digitizer. Single projection images are recorded with two laser pulses within 0.2 seconds, as determined by the laser pulse repetition rate of 10 Hz. Phantom experiments are used for characterization of the line-array. Compared to previous implementations with a single line sensor scanning around an object, with the developed array the data acquisition time can be reduced from about one hour to about one minute.

  14. Array rotation aperture synthesis for short-range imaging at millimeter wavelengths

    NASA Astrophysics Data System (ADS)

    Lucotte, B. M.; Grafulla-GonzáLez, B.; Harvey, A. R.

    2009-02-01

    Millimeter-wave interferometric synthetic aperture imagers are currently being developed for short-range applications such as concealed weapons detection. In contrast to the traditional snapshot imaging approach, we investigate the potential of mechanical scanning between the scene and the array in order to reduce the number of antennas and correlators. We assess the trade-off between this hardware reduction, the radiometric sensitivity and the imaging frame rate of the system. We show that rotational scanning achieves a more uniform coverage of the (u, v) plane than the more conventional linear scanning. We use a genetic algorithm to optimize two-dimensional arrays for maximum uniform (u, v) coverage after a rotational mechanical scan and demonstrates improvements in the array point spread function. Imaging performance is assessed with simulated millimeter-wave scenes. Results show an increased image quality is achieved with the optimized array compared with a conventional power law Y-shaped array. Finally we discuss the increased demands on system stability and calibration that the increased acquisition time of the proposed technique places.

  15. Damage characterization using guided-wave linear arrays and image compounding techniques.

    PubMed

    Higuti, Ricardo T; Martínez-Graullera, Oscar; Martín, Carlos J; Octavio, Alberto; Elvira, Luis; Montero de Espinosa, Francisco

    2010-09-01

    In this work, a high-resolution imaging method for the inspection of isotropic plate-like structures using linear arrays and Lamb waves is proposed. The evaluation of these components is limited by the low dynamic range resulting from main lobe and side lobe field patterns, and from the narrowband nature of the Lamb waves. Based on a full matrix array, synthetic aperture technique using all emitter-receiver combinations, different images from the same object are obtained by using different apodization coefficients, which are related to a trade-off between main lobe width and relative side lobe level. Several image compounding strategies have been tested and a new algorithm, based on apodization and polarity diversities between signals, is proposed. However, some effects, such as the dead zone close to the array and reverberations caused by interactions of the wavefront and defects, still limit the quality of the images. The use of spatial diversity, obtained by an additional array, introduces complementary information about the defects and improves the results of the proposed algorithm, producing high-resolution, high-contrast images. Experimental results are shown for a 1-mm-thick isotropic aluminum plate with artificial defects using linear arrays formed by 30 piezoelectric elements, with the low dispersion symmetric mode S0 at the frequency of 330 kHz.

  16. Multi-Band Miniaturized Patch Antennas for a Compact, Shielded Microwave Breast Imaging Array.

    PubMed

    Aguilar, Suzette M; Al-Joumayly, Mudar A; Burfeindt, Matthew J; Behdad, Nader; Hagness, Susan C

    2013-12-18

    We present a comprehensive study of a class of multi-band miniaturized patch antennas designed for use in a 3D enclosed sensor array for microwave breast imaging. Miniaturization and multi-band operation are achieved by loading the antenna with non-radiating slots at strategic locations along the patch. This results in symmetric radiation patterns and similar radiation characteristics at all frequencies of operation. Prototypes were fabricated and tested in a biocompatible immersion medium. Excellent agreement was obtained between simulations and measurements. The trade-off between miniaturization and radiation efficiency within this class of patch antennas is explored via a numerical analysis of the effects of the location and number of slots, as well as the thickness and permittivity of the dielectric substrate, on the resonant frequencies and gain. Additionally, we compare 3D quantitative microwave breast imaging performance achieved with two different enclosed arrays of slot-loaded miniaturized patch antennas. Simulated array measurements were obtained for a 3D anatomically realistic numerical breast phantom. The reconstructed breast images generated from miniaturized patch array data suggest that, for the realistic noise power levels assumed in this study, the variations in gain observed across this class of multi-band patch antennas do not significantly impact the overall image quality. We conclude that these miniaturized antennas are promising candidates as compact array elements for shielded, multi-frequency microwave breast imaging systems.

  17. Non-volatile resistive photo-switches for flexible image detector arrays

    NASA Astrophysics Data System (ADS)

    Nau, Sebastian; Wolf, Christoph; Sax, Stefan; List-Kratochvil, Emil J. W.

    2015-09-01

    The increasing quest to find lightweight, conformable or flexible image detectors for machine vision or medical imaging brings organic electronics into the spotlight for these fields of application. Here were we introduce a unique imaging device concept and its utilization in an organic, flexible detector array with simple passive matrix wiring. We present a flexible organic image detector array built up from non-volatile resistive multi-bit photo-switchable elements. This unique realization is based on an organic photodiode combined with an organic resistive memory device wired in a simple crossbar configuration. The presented concept exhibits significant advantages compared to present organic and inorganic detector array technologies, facilitating the detection and simultaneous storage of the image information in one detector pixel, yet also allowing for simple read-out of the information from a simple passive-matrix crossbar wiring. This concept is demonstrated for single photo-switchable pixels as well as for arrays with sizes up to 32 by 32 pixels (1024 bit). The presented results pave the way for a versatile flexible and easy-to-fabricate sensor array technology. In a final step, the concept was expanded to detection of x-rays.

  18. Development of local oscillator integrated antenna array for microwave imaging diagnostics

    NASA Astrophysics Data System (ADS)

    Kuwahara, D.; Ito, N.; Nagayama, Y.; Tsuchiya, H.; Yoshikawa, M.; Kohagura, J.; Yoshinaga, T.; Yamaguchi, S.; Kogi, Y.; Mase, A.; Shinohara, S.

    2015-12-01

    Microwave imaging diagnostics are powerful tools that are used to obtain details of complex structures and behaviors of such systems as magnetically confined plasmas. For example, microwave imaging reflectometry and microwave imaging interferometers are suitable for observing phenomena that are involved with electron density fluctuations; moreover, electron cyclotron emission imaging diagnostics enable us to accomplish the significant task of observing MHD instabilities in large tokamaks. However, microwave imaging systems include difficulties in terms of multi-channelization and cost. Recently, we solved these problems by developing a Horn-antenna Mixer Array (HMA), a 50 - 110 GHz 1-D heterodyne- type antenna array, which can be easily stacked as a 2-D receiving array, because it uses an end-fire element. However, the HMA still evidenced problems owing to the requirement for local oscillation (LO) optics and an expensive high-power LO source. To solve this problem, we have developed an upgraded HMA, named the Local Integrated Antenna array (LIA), in which each channel has an internal LO supply using a frequency multiplier integrated circuit. Therefore, the proposed antenna array eliminates the need for both the LO optics and the high-power LO source. This paper describes the principle of the LIA, and provides details about an 8 channel prototype LIA.

  19. A sidelobe suppressing near-field beamforming approach for ultrasound array imaging.

    PubMed

    He, Zhengyao; Zheng, Fan; Ma, Yuanliang; Kim, Hyung Ham; Zhou, Qifa; Shung, K Kirk

    2015-05-01

    A method is proposed to suppress sidelobe level for near-field beamforming in ultrasound array imaging. An optimization problem is established, and the second-order cone algorithm is used to solve the problem to obtain the weight vector based on the near-field response vector of a transducer array. The weight vector calculation results show that the proposed method can be used to suppress the sidelobe level of the near-field beam pattern of a transducer array. Ultrasound images following the application of weight vector to the array of a wire phantom are obtained by simulation with the Field II program, and the images of a wire phantom and anechoic sphere phantom are obtained experimentally with a 64-element 26 MHz linear phased array. The experimental and simulation results agree well and show that the proposed method can achieve a much lower sidelobe level than the conventional delay and sum beamforming method. The wire phantom image is demonstrated to focus much better and the contrast of the anechoic sphere phantom image improved by applying the proposed beamforming method.

  20. Two-Slotted Surface Coil Array for Magnetic Resonance Imaging at 4 Tesla

    SciTech Connect

    Solis, S. E.; Hernandez, J. A.; Rodriguez, A. O.; Tomasi, D.

    2008-08-11

    Arrays of antennas have been widely accepted for magnetic resonance imaging applications due to their high signal-to-noise ratio (SNR) over large volumes of interest. A new surface coil based on the magnetron tube and called slotted surface coil, has been recently introduced by our group. This coil design experimentally demonstrated a significant improvement over the circular-shaped coil when used in the receive-only mode. The slotted coils formed a two-sheet structure with a 90 deg. separation and each coil had 6 circular slots. Numerical simulations were performed using the finite element method for this coil design to study the behaviour of the array magnetic field. Then, we developed a two-coil array for brain magnetic resonance imaging to be operated at the resonant frequency of 170 MHz in the transceiver mode. Phantom images were acquired with our coil array and standard pulse sequences on a research-dedicated 4 Tesla scanner. Numerical simulations demonstrated that electromagnetic interaction between the coil elements is negligible, and that the magnetic field showed a good uniformity. In vitro images showed the feasibility of this coil array for standard pulses for high field magnetic resonance imaging.

  1. Multi-Band Miniaturized Patch Antennas for a Compact, Shielded Microwave Breast Imaging Array

    PubMed Central

    Aguilar, Suzette M.; Al-Joumayly, Mudar A.; Burfeindt, Matthew J.; Behdad, Nader; Hagness, Susan C.

    2014-01-01

    We present a comprehensive study of a class of multi-band miniaturized patch antennas designed for use in a 3D enclosed sensor array for microwave breast imaging. Miniaturization and multi-band operation are achieved by loading the antenna with non-radiating slots at strategic locations along the patch. This results in symmetric radiation patterns and similar radiation characteristics at all frequencies of operation. Prototypes were fabricated and tested in a biocompatible immersion medium. Excellent agreement was obtained between simulations and measurements. The trade-off between miniaturization and radiation efficiency within this class of patch antennas is explored via a numerical analysis of the effects of the location and number of slots, as well as the thickness and permittivity of the dielectric substrate, on the resonant frequencies and gain. Additionally, we compare 3D quantitative microwave breast imaging performance achieved with two different enclosed arrays of slot-loaded miniaturized patch antennas. Simulated array measurements were obtained for a 3D anatomically realistic numerical breast phantom. The reconstructed breast images generated from miniaturized patch array data suggest that, for the realistic noise power levels assumed in this study, the variations in gain observed across this class of multi-band patch antennas do not significantly impact the overall image quality. We conclude that these miniaturized antennas are promising candidates as compact array elements for shielded, multi-frequency microwave breast imaging systems. PMID:25392561

  2. Gallium arsenide quantum well-based far infrared array radiometric imager

    NASA Technical Reports Server (NTRS)

    Forrest, Kathrine A.; Jhabvala, Murzy D.

    1991-01-01

    We have built an array-based camera (FIRARI) for thermal imaging (lambda = 8 to 12 microns). FIRARI uses a square format 128 by 128 element array of aluminum gallium arsenide quantum well detectors that are indium bump bonded to a high capacity silicon multiplexer. The quantum well detectors offer good responsivity along with high response and noise uniformity, resulting in excellent thermal images without compensation for variation in pixel response. A noise equivalent temperature difference of 0.02 K at a scene temperature of 290 K was achieved with the array operating at 60 K. FIRARI demonstrated that AlGaAS quantum well detector technology can provide large format arrays with performance superior to mercury cadmium telluride at far less cost.

  3. Stacked phased array coils for increasing the signal-to-noise ratio in magnetic resonance imaging.

    PubMed

    Dandan Liang; Hon Tat Hui; Tat Soon Yeo; Bing Keong Li

    2013-02-01

    A new concept of using a stacked phased coil array to increase the signal-to-circuit noise ratio (SCNR) in magnetic resonance imaging (MRI) is introduced. Unlike conventional phased coil arrays, the proposed stacked phased coil array is constructed by stacking the coil elements closely together in the vertical direction. Through a proper combination of the coil terminal voltages, the SCNR is shown to increase with the square root of the number of coil elements. A prototype two-element array is constructed and an experimental method is designed to determine the combiner coefficients in a simulated MRI electromagnetic field environment. The experimental results show that the mutual coupling effect among the array coils can be totally removed and the combiner output voltage increases with the number of coil elements. This demonstrates the feasibility of the proposed method.

  4. Optics system design applying a micro-prism array of a single lens stereo image pair.

    PubMed

    Chen, Chien-Yue; Yang, Ting-Ting; Sun, Wen-Shing

    2008-09-29

    In this study we apply a micro-prism array technique to enable a single lens CCD to capture a stereo image for the simulation of double lens vision. A micro-prism array plate serves as the basis for design, which also improves the lightweight and portability of the overall system in addition to lowering the mass-production costs. Most important of all, this design possesses the characteristics of integration compatibility between general-purpose and video camera.

  5. Coded aperture imaging with self-supporting uniformly redundant arrays. [Patent application

    DOEpatents

    Fenimore, E.E.

    1980-09-26

    A self-supporting uniformly redundant array pattern for coded aperture imaging. The invention utilizes holes which are an integer times smaller in each direction than holes in conventional URA patterns. A balance correlation function is generated where holes are represented by 1's, nonholes are represented by -1's, and supporting area is represented by 0's. The self-supporting array can be used for low energy applications where substrates would greatly reduce throughput.

  6. Hemispheric Imaging of Galactic Neutral Hydrogen with a Phased Array Antenna System

    NASA Astrophysics Data System (ADS)

    Wijnholds, Stefan J.; De Bruyn, A. Ger; Bregman, Jaap D.; Bij De Vaate, Jan Geralt

    2004-06-01

    The thousand element array (THEA) system is a phased array system consisting of 1 m2 tiles having 64 Vivaldi elements each, arranged on a regular 8-by-8 grid, which has been developed as a demonstrator of technology and applicability for SKA. In this paper we present imaging results of Galactic neutral hydrogen with THEA. Measurements have been taken using a dense 2-by-2 array of four tiles as a four tile adder. The results are compared with results from the Leiden-Dwingeloo Survey, showing qualitative agreement, but also indicating that further studies are needed on the instrumental characteristics.

  7. Electrowetting liquid lens array on curved substrates for wide field of view image sensor

    NASA Astrophysics Data System (ADS)

    Bang, Yousung; Lee, Muyoung; Won, Yong Hyub

    2016-03-01

    In this research, electrowetting liquid lens array on curved substrates is developed for wide field of view image sensor. In the conventional image sensing system, this lens array is usually in the form of solid state. However, in this state, the lens array which is similar to insect-like compound eyes in nature has several limitations such as degradation of image quality and narrow field of view because it cannot adjust focal length of lens. For implementation of the more enhanced system, the curved array of lenses based on electrowetting effect is developed in this paper, which can adjust focal length of lens. The fabrication of curved lens array is conducted upon the several steps, including chamber fabrication, electrode & dielectric layer deposition, liquid injection, and encapsulation. As constituent materials, IZO coated convex glass, UV epoxy (NOA 68), DI water, and dodecane are used. The number of lenses on the fabricated panel is 23 by 23 and each lens has 1mm aperture with 1.6mm pitch between adjacent lenses. When the voltage is applied on the device, it is observed that each lens is changed from concave state to convex state. From the unique optical characteristics of curved array of liquid lenses such as controllable focal length and wide field of view, we can expect that it has potential applications in various fields such as medical diagnostics, surveillance systems, and light field photography.

  8. Apparatus and method for imaging metallic objects using an array of giant magnetoresistive sensors

    DOEpatents

    Chaiken, Alison

    2000-01-01

    A portable, low-power, metallic object detector and method for providing an image of a detected metallic object. In one embodiment, the present portable low-power metallic object detector an array of giant magnetoresistive (GMR) sensors. The array of GMR sensors is adapted for detecting the presence of and compiling image data of a metallic object. In the embodiment, the array of GMR sensors is arranged in a checkerboard configuration such that axes of sensitivity of alternate GMR sensors are orthogonally oriented. An electronics portion is coupled to the array of GMR sensors. The electronics portion is adapted to receive and process the image data of the metallic object compiled by the array of GMR sensors. The embodiment also includes a display unit which is coupled to the electronics portion. The display unit is adapted to display a graphical representation of the metallic object detected by the array of GMR sensors. In so doing, a graphical representation of the detected metallic object is provided.

  9. CMUT-based Volumetric Ultrasonic Imaging Array Design for Forward Looking ICE and IVUS Applications

    PubMed Central

    Zahorian, Jaime; Xu, Toby; Rashid, Muhammad W.; Satir, Sarp; Gurun, Gokce; Karaman, Mustafa; Hasler, Jennifer; Degertekin, F. Levent

    2014-01-01

    Designing a mechanically flexible catheter based volumetric ultrasonic imaging device for intravascular and intracardiac imaging is challenging due to small transducer area and limited number of cables. With a few parallel channels, synthetic phased array processing is necessary to acquire data from a large number of transducer elements. This increases the data collection time and hence reduces frame rate and causes artifacts due to tissue-transducer motion. Some of these drawbacks can be resolved by different array designs offered by CMUT-on-CMOS approach. We recently implemented a 2.1-mm diameter single chip 10 MHz dual ring CMUT-on-CMOS array for forward looking ICE with 64-transmit and 56-receive elements along with associated electronics. These volumetric arrays have the small element size required by high operating frequencies and achieve sub mm resolution, but the system would be susceptible to motion artifacts. To enable real time imaging with high SNR, we designed novel arrays consisting of multiple defocused annular rings for transmit aperture and a single ring receive array. The annular transmit rings are utilized to act as a high power element by focusing to a virtual ring shaped line behind the aperture. In this case, image reconstruction is performed by only receive beamforming, reducing total required firing steps from 896 to 14 with a trade-off in image resolution. The SNR of system is improved more than 5 dB for the same frequency and frame rate as compared to the dual ring array, which can be utilized to achieve the same resolution by increasing the operating frequency. PMID:23366605

  10. CMUT-based volumetric ultrasonic imaging array design for forward looking ICE and IVUS applications

    NASA Astrophysics Data System (ADS)

    Tekes, Coskun; Zahorian, Jaime; Xu, Toby; Rashid, Muhammad W.; Satir, Sarp; Gurun, Gokce; Karaman, Mustafa; Hasler, Jennifer; Degertekin, F. L.

    2013-03-01

    Designing a mechanically flexible catheter based volumetric ultrasonic imaging device for intravascular and intracardiac imaging is challenging due to small transducer area and limited number of cables. With a few parallel channels, synthetic phased array processing is necessary to acquire data from a large number of transducer elements. This increases the data collection time and hence reduces frame rate and causes artifacts due to tissue-transducer motion. Some of these drawbacks can be resolved by different array designs offered by CMUT-on-CMOS approach. We recently implemented a 2.1-mm diameter single chip 10 MHz dual ring CMUT-on-CMOS array for forward looking ICE with 64-transmit and 56-receive elements along with associated electronics. These volumetric arrays have the small element size required by high operating frequencies and achieve sub mm resolution, but the system would be susceptible to motion artifacts. To enable real time imaging with high SNR, we designed novel arrays consisting of multiple defocused annular rings for transmit aperture and a single ring receive array. The annular transmit rings are utilized to act as a high power element by focusing to a virtual ring shaped line behind the aperture. In this case, image reconstruction is performed by only receive beamforming, reducing total required firing steps from 896 to 14 with a trade-off in image resolution. The SNR of system is improved more than 5 dB for the same frequency and frame rate as compared to the dual ring array, which can be utilized to achieve the same resolution by increasing the operating frequency.

  11. Surface estimation methods with phased-arrays for adaptive ultrasonic imaging in complex components

    NASA Astrophysics Data System (ADS)

    Robert, S.; Calmon, P.; Calvo, M.; Le Jeune, L.; Iakovleva, E.

    2015-03-01

    Immersion ultrasonic testing of structures with complex geometries may be significantly improved by using phased-arrays and specific adaptive algorithms that allow to image flaws under a complex and unknown interface. In this context, this paper presents a comparative study of different Surface Estimation Methods (SEM) available in the CIVA software and used for adaptive imaging. These methods are based either on time-of-flight measurements or on image processing. We also introduce a generalized adaptive method where flaws may be fully imaged with half-skip modes. In this method, both the surface and the back-wall of a complex structure are estimated before imaging flaws.

  12. Design and fabrication of Fourier spectral filter array for multispectral imaging

    NASA Astrophysics Data System (ADS)

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

    2016-09-01

    Multispectral imaging has the capability to identify the state of objects based on their spectral characteristics. These are features not available with conventional color imaging based on metameric RGB (red, green and blue) colors alone. Current multispectral imaging systems use narrowband filters to capture the spectral content of a scene, which necessitates different filters to be designed and applied for each application. Previously, we demonstrated the concept of Fourier multispectral imaging using filters with sinusoidally varying transmittance [1, 2]. In this paper, we report to the design of a five channel, spatially multiplexed pixel filter array. This enables single-shot images and makes it possible to capture scenes containing moving objects.

  13. Analysis of Image Formation with Thinned Random Arrays

    DTIC Science & Technology

    1979-06-01

    FORCE OFFICE OF SCIENTIFIC RESEARCH Building 410 i Boiling Air Force Base , Washington, DC 20332 A ~VA Approved for public rolo~ae; UT G’ -7 7 . . . . 7...However, there is no general theory available for the algorithmic design of this class of arrays. Many of the designs to date have been based on trial- and...system. The system impulse function is directly related 14 to the pupil function by a Fourier trmnsformation: h(x,y) ff P(•,) 6 -i2T(xc+Y8) dadO . (3

  14. Floating volumetric image formation using a dihedral corner reflector array device.

    PubMed

    Miyazaki, Daisuke; Hirano, Noboru; Maeda, Yuki; Yamamoto, Siori; Mukai, Takaaki; Maekawa, Satoshi

    2013-01-01

    A volumetric display system using an optical imaging device consisting of numerous dihedral corner reflectors placed perpendicular to the surface of a metal plate is proposed. Image formation by the dihedral corner reflector array (DCRA) is free from distortion and focal length. In the proposed volumetric display system, a two-dimensional real image is moved by a mirror scanner to scan a three-dimensional (3D) space. Cross-sectional images of a 3D object are displayed in accordance with the position of the image plane. A volumetric image is observed as a stack of the cross-sectional images. The use of the DCRA brings compact system configuration and volumetric real image generation with very low distortion. An experimental volumetric display system including a DCRA, a galvanometer mirror, and a digital micro-mirror device was constructed to verify the proposed method. A volumetric image consisting of 1024×768×400 voxels was formed by the experimental system.

  15. Real-time system for imaging and object detection with a multistatic GPR array

    DOEpatents

    Paglieroni, David W; Beer, N Reginald; Bond, Steven W; Top, Philip L; Chambers, David H; Mast, Jeffrey E; Donetti, John G; Mason, Blake C; Jones, Steven M

    2014-10-07

    A method and system for detecting the presence of subsurface objects within a medium is provided. In some embodiments, the imaging and detection system operates in a multistatic mode to collect radar return signals generated by an array of transceiver antenna pairs that is positioned across the surface and that travels down the surface. The imaging and detection system pre-processes the return signal to suppress certain undesirable effects. The imaging and detection system then generates synthetic aperture radar images from real aperture radar images generated from the pre-processed return signal. The imaging and detection system then post-processes the synthetic aperture radar images to improve detection of subsurface objects. The imaging and detection system identifies peaks in the energy levels of the post-processed image frame, which indicates the presence of a subsurface object.

  16. Effect of roughness on imaging and characterizing rough crack-like defect using ultrasonic arrays

    NASA Astrophysics Data System (ADS)

    Zhang, J.; Drinkwater, B. W.; Wilcox, P. D.

    2012-05-01

    All naturally occurring crack-like defects in solid structures are rough to some degree, which can affect defect inspection and characterization. Based on the simulated array data for various rough cracks and the total focusing method imaging algorithm, the effect of roughness on defect imaging and characterization was discussed. The array data was simulated by using the forward model combining with scattering matrices for various rough cracks. The scattering matrix describes the scattering field of a scatterer from all possible incident and scattering directions. It is shown that roughness can be either beneficial or detrimental to the detectability of a crack-like defect, depending on the defect characteristics such as length, roughness, correlation length, orientation angle, and array inspection configuration. It is also shown that roughness can cause the underestimation of length of rough crack-like defects by using the image-based approach.

  17. Application and Design of Satellite Infrared Spectral Imaging Radiometers with Uncooled Microbolometer Array Detectors

    NASA Technical Reports Server (NTRS)

    Spinhirne, James; Lancaster, Regie; Maschhoff, Kevin; Starr, David OC (Technical Monitor)

    2001-01-01

    Uncooled infrared microbolometer array detectors have application for space borne spectral imaging radiometer of several types to lower size, power and cost and provide improved performance. Other advantages of eliminating cooling requirement are simplified systems, simplified satellite integration and improved reliability. A prototype microbolometer instrument for cloud observations was flown on the STS-85 space shuttle mission. Extensive data were acquired at_km resolution at four thermal infrared wavelength bands. From the 320x280 detector array both spectral and angular information can be used to advantage in cloud retrievals and has been demonstrated. An engineering model Compact Visible and Infrared Imaging Radiometer (COVIR) for small satellite missions has been developed. Application of advanced microbolometer array detectors for three axis stabilized GOES thermal imagers has been studied.

  18. Fluorescence microscopy imaging with a Fresnel zone plate array based optofluidic microscope

    PubMed Central

    Han, Chao; Lee, Lap Man; Yang, Changhuei

    2013-01-01

    We report the implementation of an on-chip microscope system, termed fluorescence optofluidic microscope (FOFM), which is capable of fluorescence microscopy imaging of samples in fluid media. The FOFM employs an array of Fresnel zone plates (FZP) to generate an array of focused light spots within a microfluidic channel. As a sample flows through the channel and across the array of focused light spots, the fluorescence emissions are collected by a filter-coated CMOS sensor, which serves as the channel's floor. The collected data can then be processed to render fluorescence microscopy images at a resolution determined by the focused light spot size (experimentally measured as 0.65 μm FWHM). In our experiments, our established resolution was 1.0 μm due to Nyquist criterion consideration. As a demonstration, we show that such a system can be used to image the cell nuclei stained by Acridine Orange and cytoplasm labeled by Qtracker®. PMID:21935556

  19. Transmission and reflective ultrasound images using PE-CMOS sensor array

    NASA Astrophysics Data System (ADS)

    Lo, Shih-Chung B.; Liu, Chu Chuan; Freedman, Matthew T.; Kula, John; Lasser, Bob; Lasser, Marvin E.; Wang, Yue

    2005-04-01

    The purpose of this study is to investigate the imaging capability of a CMOS (PE-CMOS) ultrasound sensing array coated with piezoelectric material. There are three main components in the laboratory setup: (1) a transducer operated at 3.5MHz-7MHz frequency generating unfocused ultrasound plane waves, (2) an acoustic compound lens that collects the energy and focuses ultrasound signals onto the detector array, and (3) a PE-CMOS ultrasound sensing array (Model I400, Imperium Inc. Silver Spring, MD) that receives the ultrasound and converts the energy to analog voltage followed by a digital conversion. The PE-CMOS array consists of 128×128 pixel elements with 85μm per pixel. The major improvement of the new ultrasound sensor array has been in its dynamic range. We found that the current PE-CMOS ultrasound sensor (Model I400) possesses a dynamic range up to 70dB. The system can generate ultrasound attenuation images of soft tissues which are similar to digital images obtained from an x-ray projection system. In the paper, we also show that the prototype system can image bone fractures using reflective geometry.

  20. Top-orthogonal-to-bottom-electrode (TOBE) CMUT arrays for 3-D ultrasound imaging.

    PubMed

    Sampaleanu, Alex; Zhang, Peiyu; Kshirsagar, Abhijeet; Moussa, Walied; Zemp, Roger J

    2014-02-01

    Two-dimensional ultrasound arrays hold great promise for 3-D imaging; however, wiring of each channel becomes impractical for large arrays or for small-footprint catheter probes for which the number of wires must be limited. Capacitive micromachined ultrasound transducers offer a promising solution for such 2-D array applications, but channel routing is still non-trivial. A top-orthogonal-to-bottom-electrode (TOBE) 2-D CMUT array architecture is presented along with row-column addressing schemes for low-channel-count 3-D ultrasound imaging. An N × N TOBE array is capable of obtaining 3-D images using only 2N channels. An interfacing scheme is presented in which transmit-receive signals are routed along rows while bias voltages are applied along columns, effectively allowing for single-element transmit/receive control. Simulations demonstrated potentially finer resolution and improved side lobe suppression over a previously published row-column-based imaging method. Laser vibrometer testing was done to measure membrane displacement in air and confirmed that single-element air-coupled actuation in transmit mode could be achieved using our proposed interfacing scheme. Acoustic testing was also performed in both transmit and receive modes to characterize the ability of the proposed interfacing scheme to achieve dominant-element transmission and reception in immersion operation. It was seen that membrane displacement in both modes was indeed largely confined to the active area.

  1. Imaging performance of the hybrid pixel detectors XPAD3-S

    NASA Astrophysics Data System (ADS)

    Brunner, F. Cassol; Clemens, J. C.; Hemmer, C.; Morel, C.

    2009-03-01

    Hybrid pixel detectors, originally developed for tracking particles in high-energy physics experiments, have recently been used in material sciences and macromolecular crystallography. Their capability to count single photons and to apply a threshold on the photon energy suggests that they could be optimal digital x-ray detectors in low energy beams such as for small animal computed tomography (CT). To investigate this issue, we have studied the imaging performance of photon counting hybrid pixel detectors based on the XPAD3-S chip. Two detectors are considered, connected either to a Si or to a CdTe sensor, the latter being of interest for its higher efficiency. Both a standard 'International Electrotechnical Commission' (IEC) mammography beam and a beam used for mouse CT results published in the literature are employed. The detector stability, linearity and noise are investigated as a function of the dose for several imaging exposures (~0.1-400 µGy). The perfect linearity of both detectors is confirmed, but an increase in internal noise for counting statistics higher than ~5000 photons has been found, corresponding to exposures above ~110 µGy and ~50 µGy for the Si and CdTe sensors, respectively. The noise power spectrum (NPS), the modulation transfer function (MTF) and the detective quantum efficiency (DQE) are then measured for two energy threshold configurations (5 keV and 18 keV) and three doses (~3, 30 and 300 µGy), in order to obtain a complete estimation of the detector performances. In general, the CdTe sensor shows a clear superiority with a maximal DQE(0) of ~1, thanks to its high efficiency (~100%). The DQE of the Si sensor is more dependent on the radiation quality, due to the energy dependence of its efficiency its maximum is ~0.4 with respect to the softer radiation. Finally, we compare the XPAD3-S DQE with published curves of other digital devices in a similar radiation condition. The XPAD3-S/CdTe detector appears to be the best with the highest

  2. Biochip functionalization using electrowetting-on-dielectric digital microfluidics for surface plasmon resonance imaging detection of DNA hybridization.

    PubMed

    Malic, Lidija; Veres, Teodor; Tabrizian, Maryam

    2009-03-15

    This work reports on a dynamically configurable micro-array surface plasmon resonance biochip platform. The platform comprises a digital electrowetting-on-dielectric (EWOD) microfluidic device tailored to surface plasmon resonance imaging (SPRi). We demonstrate its application for simultaneous immobilization of different DNA probes at the designated detection sites on-chip from sub-microL volume solutions in combination with multichannel label-free real-time detection of subsequent hybridization reactions. Successful on-chip DNA probe dilution and immobilization is also demonstrated using SPRi hybridization detection. Furthermore, active control of the immobilized probe density and orientation is achieved under an applied potential using the electric interface of the EWOD device. For low probe densities, under negative applied potential, the DNA hybridization efficiency is enhanced compared to passive probe immobilization, yielding a two-fold SPR signal increase within only 8min of hybridization. EWOD microfluidic platform coupled with SPRi promises to dramatically increase the speed of detection and quantification of biomolecular interactions while reducing reagent consumption. The proposed system would enable the development of high-throughput, rapid and ultrasensitive detection of biomolecules beyond DNA microarray applications.

  3. Development of a spherically focused phased array transducer for ultrasonic image-guided hyperthermia.

    PubMed

    Liu, Jingfei; Foiret, Josquin; Stephens, Douglas N; Le Baron, Olivier; Ferrara, Katherine W

    2016-07-21

    A 1.5 MHz prolate spheroidal therapeutic array with 128 circular elements was designed to accommodate standard imaging arrays for ultrasonic image-guided hyperthermia. The implementation of this dual-array system integrates real-time therapeutic and imaging functions with a single ultrasound system (Vantage 256, Verasonics). To facilitate applications involving small animal imaging and therapy the array was designed to have a beam depth of field smaller than 3.5 mm and to electronically steer over distances greater than 1 cm in both the axial and lateral directions. In order to achieve the required f number of 0.69, 1-3 piezocomposite modules were mated within the transducer housing. The performance of the prototype array was experimentally evaluated with excellent agreement with numerical simulation. A focal volume (2.70 mm (axial)  ×  0.65 mm (transverse)  ×  0.35 mm (transverse)) defined by the  -6 dB focal intensity was obtained to address the dimensions needed for small animal therapy. An electronic beam steering range defined by the  -3 dB focal peak intensity (17 mm (axial)  ×  14 mm (transverse)  ×  12 mm (transverse)) and  -8 dB lateral grating lobes (24 mm (axial)  ×  18 mm (transverse)  ×  16 mm (transverse)) was achieved. The combined testing of imaging and therapeutic functions confirmed well-controlled local heating generation and imaging in a tissue mimicking phantom. This dual-array implementation offers a practical means to achieve hyperthermia and ablation in small animal models and can be incorporated within protocols for ultrasound-mediated drug delivery.

  4. Development of a spherically focused phased array transducer for ultrasonic image-guided hyperthermia

    NASA Astrophysics Data System (ADS)

    Liu, Jingfei; Foiret, Josquin; Stephens, Douglas N.; Le Baron, Olivier; Ferrara, Katherine W.

    2016-07-01

    A 1.5 MHz prolate spheroidal therapeutic array with 128 circular elements was designed to accommodate standard imaging arrays for ultrasonic image-guided hyperthermia. The implementation of this dual-array system integrates real-time therapeutic and imaging functions with a single ultrasound system (Vantage 256, Verasonics). To facilitate applications involving small animal imaging and therapy the array was designed to have a beam depth of field smaller than 3.5 mm and to electronically steer over distances greater than 1 cm in both the axial and lateral directions. In order to achieve the required f number of 0.69, 1-3 piezocomposite modules were mated within the transducer housing. The performance of the prototype array was experimentally evaluated with excellent agreement with numerical simulation. A focal volume (2.70 mm (axial)  ×  0.65 mm (transverse)  ×  0.35 mm (transverse)) defined by the  -6 dB focal intensity was obtained to address the dimensions needed for small animal therapy. An electronic beam steering range defined by the  -3 dB focal peak intensity (17 mm (axial)  ×  14 mm (transverse)  ×  12 mm (transverse)) and  -8 dB lateral grating lobes (24 mm (axial)  ×  18 mm (transverse)  ×  16 mm (transverse)) was achieved. The combined testing of imaging and therapeutic functions confirmed well-controlled local heating generation and imaging in a tissue mimicking phantom. This dual-array implementation offers a practical means to achieve hyperthermia and ablation in small animal models and can be incorporated within protocols for ultrasound-mediated drug delivery.

  5. System Design and Wide-field Imaging Aspects of Synthesis Arrays with Phased Array Stations

    NASA Astrophysics Data System (ADS)

    Bregman, Jacob Dirk

    2012-12-01

    Dit proefschrift betreft het ontwerpen van synthese radiotelescopen, zoals LOFAR. Bekende ontwerpprincipes worden gecombineerd met een visie op technologische mogelijkheden die in de nabije toekomst binnen handbereik komen. De centrale vraag daarbij is hoe wetenschappelijke gebruikers met een gegeven budget een optimaal resultaat kunnen behalen. Systeemontwerp begint met een analyse van de fundamentele beperkingen van groothoek beeldvorming met apertuursynthese en van praktische beperkingen zoals verstoring door de ionosfeer. Deze analyse heeft geleid tot een aantal schaalwetten voor telescoop- en antenne-configuratie en voor de vereiste digitale processing. In een array antenne worden de signalen van een aantal antennes opgeteld tot een versterkt signaal uit een bepaalde richting. Deze array technologie geeft de mogelijkheid een gegeven aantal eenvoudige antennes optimaal te verdelen over een aantal stations. Ons onderzoek heeft laten zien dat de stations een minimum grootte nodig hebben om verstoring door de ionosfeer over het gehele beeldveld te kunnen corrigeren. Te kleine stations kunnen maar in een beperkt deel van hun grote beeldveld voldoende scherpte krijgen. Een te beperkt aantal stations leidt echter tot toename van ruis in het beeld die met extra beeldbewerking deels is te verwijderen. Een belangrijk resultaat van het werk is het ontwerp voor twee nieuwe methoden van beeldvorming waarbij de computer bewerking is teruggebracht tot een theoretisch minimum dat evenredig is met het oppervlak van het totale beeldveld gemeten in resolutie elementen. Voor een voldoend groot aantal stations is een optimale verdeling mogelijk waarmee maximale scherpte en minimale ruis is te realiseren binnen een totaal budget dat niet door de kosten van de benodigde computing faciliteiten wordt gedomineerd.

  6. Analysis of Molecular Cytogenetic Alteration in Rhabdomyosarcoma by Array Comparative Genomic Hybridization

    PubMed Central

    Liu, Chunxia; Li, Dongliang; Jiang, Jinfang; Hu, Jianming; Zhang, Wei; Chen, Yunzhao; Cui, Xiaobin; Qi, Yan; Zou, Hong; Zhang, WenJie; Li, Feng

    2014-01-01

    Rhabdomyosarcoma (RMS) is the most common pediatric soft tissue sarcoma with poor prognosis. The genetic etiology of RMS remains largely unclear underlying its development and progression. To reveal novel genes more precisely and new therapeutic targets associated with RMS, we used high-resolution array comparative genomic hybridization (aCGH) to explore tumor-associated copy number variations (CNVs) and genes in RMS. We confirmed several important genes by quantitative real-time polymerase chain reaction (QRT-PCR). We then performed bioinformatics-based functional enrichment analysis for genes located in the genomic regions with CNVs. In addition, we identified miRNAs located in the corresponding amplification and deletion regions and performed miRNA functional enrichment analysis. aCGH analyses revealed that all RMS showed specific gains and losses. The amplification regions were 12q13.12, 12q13.3, and 12q13.3–q14.1. The deletion regions were 1p21.1, 2q14.1, 5q13.2, 9p12, and 9q12. The recurrent regions with gains were 12q13.3, 12q13.3–q14.1, 12q14.1, and 17q25.1. The recurrent regions with losses were 9p12–p11.2, 10q11.21–q11.22, 14q32.33, 16p11.2, and 22q11.1. The mean mRNA level of GLI1 in RMS was 6.61-fold higher than that in controls (p = 0.0477) by QRT-PCR. Meanwhile, the mean mRNA level of GEFT in RMS samples was 3.92-fold higher than that in controls (p = 0.0354). Bioinformatic analysis showed that genes were enriched in functions such as immunoglobulin domain, induction of apoptosis, and defensin. Proto-oncogene functions were involved in alveolar RMS. miRNAs that located in the amplified regions in RMS tend to be enriched in oncogenic activity (miR-24 and miR-27a). In conclusion, this study identified a number of CNVs in RMS and functional analyses showed enrichment for genes and miRNAs located in these CNVs regions. These findings may potentially help the identification of novel biomarkers and/or drug targets implicated in diagnosis of

  7. Application of array-comparative genomic hybridization in tetralogy of Fallot

    PubMed Central

    Liu, Lin; Wang, Hong-Dan; Cui, Cun-Ying; Wu, Dong; Li, Tao; Fan, Tai-Bing; Peng, Bang-Tian; Zhang, Lian-Zhong; Wang, Cheng-Zeng

    2016-01-01

    Abstract To explore the underlying pathogenesis and provide references for genetic counseling and prenatal gene diagnosis, we analyzed the chromosome karyotypes and genome-wide copy number variations (CNVs) in 86 patients with tetralogy of Fallot (TOF) by G-banding karyotype analysis and array-comparative genomic hybridization (aCGH), respectively. And then quantitative polymerase chain reaction was used to validate these candidate CNVs. Based on their different properties, CNVs were categorized into benign CNVs, suspiciously pathogenic CNVs, and indefinite CNVs. Data analysis was based on public databases such as UCSC, DECIPHER, DGV, ISCA, and OMIM. The karyotype was normal in all the 86 patients with TOF. CNVs were detected in 11 patients by aCGH and quantitative polymerase chain reaction. Patient no. 0001, 0010, and 0029 had 2.52-Mb deletion in the chromosome 22q11.21 region; patient no. 0008 had both 595- and 428-kb duplications, respectively, in 12p12.3p12.2 and 14q23.2q23.3 regions; patient no. 0009 had 1.46-Mb duplication in the 1q21.1q21.2 region; patient no. 0016 had 513-kb duplication in the 1q42.13 region; patient no. 0024 had 292-kb duplication in the 16q11.2 region; patient no. 0026 had 270-kb duplication in the 16q24.1 region; patient no. 0028 had 222-kb deletion in the 7q31.1 region; patient no. 0033 had 1.73-Mb duplication in the 17q12 region; and patient no. 0061 had 5.79-Mb deletion in the 1p36.33p36.31 region. aCGH can accurately detect CNVs in the patients with TOF. This is conducive to genetic counseling and prenatal diagnosis for TOF and provides a new clue and theoretical basis for exploring the pathogenesis of congenital heart disease. PMID:27930557

  8. A Dual-Layer Transducer Array for 3-D Rectilinear Imaging

    PubMed Central

    Yen, Jesse T.; Seo, Chi Hyung; Awad, Samer I.; Jeong, Jong S.

    2010-01-01

    2-D arrays for 3-D rectilinear imaging require very large element counts (16,000–65,000). The difficulties in fabricating and interconnecting 2-D arrays with a large number of elements (>5,000) have limited the development of suitable transducers for 3-D rectilinear imaging. In this paper, we propose an alternative solution to this problem by using a dual-layer transducer array design. This design consists of two perpendicular 1-D arrays for clinical 3-D imaging of targets near the transducer. These targets include the breast, carotid artery, and musculoskeletal system. This transducer design reduces the fabrication complexity and the channel count making 3-D rectilinear imaging more realizable. With this design, an effective N × N 2-D array can be developed using only N transmitters and N receivers. This benefit becomes very significant when N becomes greater than 128, for example. To demonstrate feasibility, we constructed a 4 × 4 cm prototype dual-layer array. The transmit array uses diced PZT-5H elements, and the receive array is a single sheet of undiced P[VDF-TrFE] copolymer. The receive elements are defined by the copper traces on the flexible interconnect circuit. The measured −6 dB fractional bandwidth was 80% with a center frequency of 4.8 MHz. At 5 MHz, the nearest neighbor crosstalk of the PZT array and PVDF array was −30.4 ± 3.1 dB and −28.8 ± 3.7 dB respectively. This dual-layer transducer was interfaced with an Ultrasonix Sonix RP system, and a synthetic aperture 3-D data set was acquired. We then performed off-line 3-D beamforming to obtain volumes of nylon wire targets. The theoretical lateral beamwidth was 0.52 mm compared to measured beamwidths of 0.65 mm and 0.67 mm in azimuth and elevation respectively. 3-D images of an 8 mm diameter anechoic cyst phantom were also acquired. PMID:19213647

  9. Development of a C-Scan phased array ultrasonic imaging system using a 64-element 35MHz transducer

    NASA Astrophysics Data System (ADS)

    Zheng, Fan; Hu, Changhong; Zhang, Lequan; Snook, Kevin; Liang, Yu; Hackenberger, Wesley S.; Liu, Ruibin; Geng, Xuecang; Jiang, Xiaoning; Shung, K. Kirk

    2011-04-01

    Phased array imaging systems provide the features of electronic beam steering and dynamic depth focusing that cannot be obtained with conventional linear array systems. This paper presents a system design of a digital ultrasonic imaging system, which is capable of handling a 64-element 35MHz center frequency phased array transducer. The system consists of 5 parts: an analog front-end, a data digitizer, a DSP based beamformer, a computer controlled motorized linear stage, and a computer for post image processing and visualization. Using a motorized linear stage, C-scan images, parallel to the surface of scanned objects may be generated. This digital ultrasonic imaging system in combination a 35 MHz phased array appears to be a promising tool for NDT applications with high spatial resolution. It may also serve as an excellent research platform for high frequency phased array design and testing as well as ultrasonic array signal algorithm developing using system's raw RF data acquisition function.

  10. A hybrid deconvolution approach to separate static and moving single-tone acoustic sources by phased microphone array measurements

    NASA Astrophysics Data System (ADS)

    Mo, Pinxi; Jiang, Weikang

    2017-02-01

    Beamforming approaches are developed to locate and quantify either static or moving acoustic sources by phased microphone array measurements. They would meet difficulties in mapping combined sources consisting of both static and moving sources. In this work, a hybrid deconvolution approach is proposed to separate static and moving single-tone sources. The approach is derived based on the source independence assumption as in the Deconvolution Approach for the Mapping of Acoustic Sources (DAMAS). The static beamforming and the moving beamforming are integrated to construct a linear matrix equation. The source distributions for the static sources and moving sources are simultaneously obtained by solving the equation. Numerical simulations and experiments were implemented on the combined sources with one static source and one rotating source. From the results, the hybrid deconvolution approach shows its effectiveness in separating the two sources, even with large source strength differences.

  11. Array Processing for Radar Clutter Reduction and Imaging of Ice-Bed Interface

    NASA Astrophysics Data System (ADS)

    Gogineni, P.; Leuschen, C.; Li, J.; Hoch, A.; Rodriguez-Morales, F.; Ledford, J.; Jezek, K.

    2007-12-01

    A major challenge in sounding of fast-flowing glaciers in Greenland and Antarctica is surface clutter, which masks weak returns from the ice-bed interface. The surface clutter is also a major problem in sounding and imaging sub-surface interfaces on Mars and other planets. We successfully applied array-processing techniques to reduce clutter and image ice-bed interfaces of polar ice sheets. These techniques and tools have potential applications to planetary observations. We developed a radar with array-processing capability to measure thickness of fast-flowing outlet glaciers and image the ice-bed interface. The radar operates over the frequency range from 140 to 160 MHz with about an 800- Watt peak transmit power with transmit and receive antenna arrays. The radar is designed such that pulse width and duration are programmable. The transmit-antenna array is fed with a beamshaping network to obtain low sidelobes. We designed the receiver such that it can process and digitize signals for each element of an eight- channel array. We collected data over several fast-flowing glaciers using a five-element antenna array, limited by available hardpoints to mount antennas, on a Twin Otter aircraft during the 2006 field season and a four-element array on a NASA P-3 aircraft during the 2007 field season. We used both adaptive and non-adaptive signal-processing algorithms to reduce clutter. We collected data over the Jacobshavn Isbrae and other fast-flowing outlet glaciers, and successfully measured the ice thickness and imaged the ice-bed interface. In this paper, we will provide a brief description of the radar, discuss clutter-reduction algorithms, present sample results, and discuss the application of these techniques to planetary observations.

  12. Experimental characterization of the lower hybrid wave field on the first pass using a magnetic probe array

    NASA Astrophysics Data System (ADS)

    Shinya, T.; Baek, S. G.; Wallace, G. M.; Parker, R. R.; Shiraiwa, S.; Takase, Y.

    2016-10-01

    Experimental characterization of the lower hybrid (LH) wave propagation from the launcher to the core plasma is important to validate an antenna spectrum model and to identify parasitic wave-edge plasma interactions occurring in front of the launcher. On Alcator C-Mod, the wave frequency spectrum and dominant parallel wavenumber are characterized with two probe arrays installed near the edge plasma. The first one is mounted on a radially movable structure that is about 108 deg toroidally away from the launcher. A phasing scan experiment at moderate density suggests a resonance-cone propagation of the launched slow LH wave with a finite spectral width. As plasma density is raised, the measured power decreases, correlated with the observed loss of efficiency. Recently, the second probe array with an increased number of probes has been installed on a limiter that is 54 deg. toroidally away from the launcher, which is expected to be dominantly sensitive to the wave-field directly leaving the launcher. An initial measurement shows that the probe array detects a coherent wave field. A full-wave model to evaluate the wave electric-field pattern in front of the probe array is under development. If available, further experimental and modeling results will be presented. Supported by USDoE Award(s) DE-FC02-99ER54512 and Japan/U.S. Cooperation in Fusion Research and Development.

  13. Comparison of polystyrene scintillator fiber array and monolithic polystyrene for neutron imaging and radiography

    NASA Astrophysics Data System (ADS)

    Simpson, R.; Cutler, T. E.; Danly, C. R.; Espy, M. A.; Goglio, J. H.; Hunter, J. F.; Madden, A. C.; Mayo, D. R.; Merrill, F. E.; Nelson, R. O.; Swift, A. L.; Wilde, C. H.; Zocco, T. G.

    2016-11-01

    The neutron imaging diagnostic at the National Ignition Facility has been operating since 2011 generating neutron images of deuterium-tritium (DT) implosions at peak compression. The current design features a scintillating fiber array, which allows for high imaging resolution to discern small-scale structure within the implosion. In recent years, it has become clear that additional neutron imaging systems need to be constructed in order to provide 3D reconstructions of the DT source and these additional views need to be on a shorter line of sight. As a result, there has been increased effort to identify new image collection techniques that improve upon imaging resolution for these next generation neutron imaging systems, such as monolithic deuterated scintillators. This work details measurements performed at the Weapons Neutron Research Facility at Los Alamos National Laboratory that compares the radiographic abilities of the fiber scintillator with a monolithic scintillator, which may be featured in a future short line of sight neutron imaging systems.

  14. Planetary Radar Imaging with the Deep-Space Network's 34 Meter Uplink Array

    NASA Technical Reports Server (NTRS)

    Vilnrotter, V.; Tsao, P.; Lee, D.; Cornish, T.; Jao, J.; Slade, M.

    2011-01-01

    A coherent uplink array consisting of up to three 34-meter antennas of NASA's Deep Space Network has been developed for the primary purpose of increasing EIRP at the spacecraft. Greater EIRP ensures greater reach, higher uplink data rates for command and configuration control, as well as improved search and recovery capabilities during spacecraft emergencies. It has been conjectured that Doppler-delay radar imaging of lunar targets can be extended to planetary imaging, where the long baseline of the uplink array can provide greater resolution than a single antenna, as well as potentially higher EIRP. However, due to the well known R-4 loss in radar links, imaging of distant planets is a very challenging endeavor, requiring accurate phasing of the Uplink Array antennas, cryogenically cooled low-noise receiver amplifiers, and sophisticated processing of the received data to extract the weak echoes characteristic of planetary radar. This article describes experiments currently under way to image the planets Mercury and Venus, highlights improvements in equipment and techniques, and presents planetary images obtained to date with two 34 meter antennas configured as a coherently phased Uplink Array.

  15. Planetary Radar Imaging with the Deep-Space Network's 34 Meter Uplink Array

    NASA Technical Reports Server (NTRS)

    Vilnrotter, Victor; Tsao, P.; Lee, D.; Cornish, T.; Jao, J.; Slade, M.

    2011-01-01

    A coherent Uplink Array consisting of two or three 34-meter antennas of NASA's Deep Space Network has been developed for the primary purpose of increasing EIRP at the spacecraft. Greater EIRP ensures greater reach, higher uplink data rates for command and configuration control, as well as improved search and recovery capabilities during spacecraft emergencies. It has been conjectured that Doppler-delay radar imaging of lunar targets can be extended to planetary imaging, where the long baseline of the uplink array can provide greater resolution than a single antenna, as well as potentially higher EIRP. However, due to the well known R4 loss in radar links, imaging of distant planets is a very challenging endeavor, requiring accurate phasing of the Uplink Array antennas, cryogenically cooled low-noise receiver amplifiers, and sophisticated processing of the received data to extract the weak echoes characteristic of planetary radar. This article describes experiments currently under way to image the planets Mercury and Venus, highlights improvements in equipment and techniques, and presents planetary images obtained to date with two 34 meter antennas configured as a coherently phased Uplink Array.

  16. Hybrid magnetic nanostructures (MNS) for magnetic resonance imaging applications.

    PubMed

    De, Mrinmoy; Chou, Stanley S; Joshi, Hrushikesh M; Dravid, Vinayak P

    2011-11-01

    The development of MRI contrast agents has experienced its version of the gilded age over the past decade, thanks largely to the rapid advances in nanotechnology. In addition to progress in single mode contrast agents, which ushered in unprecedented R(1) or R(2) sensitivities, there has also been a boon in the development of agents covering more than one mode of detection. These include T(1)-PET, T(2)-PET T(1)-optical, T(2)-optical, T(1)-T(2) agents and many others. In this review, we describe four areas which we feel have experienced particular growth due to nanotechnology, specifically T(2) magnetic nanostructure development, T(1)/T(2)-optical dual mode agents, and most recently the T(1)-T(2) hybrid imaging systems. In each of these systems, we describe applications including in vitro, in vivo usage and assay development. In all, while the benefits and drawbacks of most MRI contrast agents depend on the application at hand, the recent development in multimodal nanohybrids may curtail the shortcomings of single mode agents in diagnostic and clinical settings by synergistically incorporating functionality. It is hoped that as nanotechnology advances over the next decade, it will produce agents with increased diagnostics and assay relevant capabilities in streamlined packages that can meaningfully improve patient care and prognostics. In this review article, we focus on T(2) materials, its surface functionalization and coupling with optical and/or T(1) agents.

  17. Clinical utility of array comparative genomic hybridization: uncovering tumor susceptibility in individuals with developmental delay.

    PubMed

    Adam, Margaret P; Justice, April N; Schelley, Susan; Kwan, Andrea; Hudgins, Louanne; Martin, Christa L

    2009-01-01

    Microarray-based comparative genomic hybridization can determine genome-wide copy number alterations at the kilobase level. We highlight the clinical utility of microarray-based comparative genomic hybridization in determining tumor susceptibility in 3 patients with dysmorphic features and developmental delay, likely decreasing both morbidity and mortality in these patients.

  18. Single photon imaging and timing array sensor apparatus and method

    DOEpatents

    Smith, R. Clayton

    2003-06-24

    An apparatus and method are disclosed for generating a three-dimension image of an object or target. The apparatus is comprised of a photon source for emitting a photon at a target. The emitted photons are received by a photon receiver for receiving the photon when reflected from the target. The photon receiver determines a reflection time of the photon and further determines an arrival position of the photon on the photon receiver. An analyzer is communicatively coupled to the photon receiver, wherein the analyzer generates a three-dimensional image of the object based upon the reflection time and the arrival position.

  19. Beamforming of Ultrasound Signals from 1-D and 2-D Arrays under Challenging Imaging Conditions

    NASA Astrophysics Data System (ADS)

    Jakovljevic, Marko

    Beamforming of ultrasound signals in the presence of clutter, or partial aperture blockage by an acoustic obstacle can lead to reduced visibility of the structures of interest and diminished diagnostic value of the resulting image. We propose new beamforming methods to recover the quality of ultrasound images under such challenging conditions. Of special interest are the signals from large apertures, which are more susceptible to partial blockage, and from commercial matrix arrays that suffer from low sensitivity due to inherent design/hardware limitations. A coherence-based beamforming method designed for suppressing the in vivo clutter, namely Short-lag Spatial Coherence (SLSC) Imaging, is first implemented on a 1-D array to enhance visualization of liver vasculature in 17 human subjects. The SLSC images show statistically significant improvements in vessel contrast and contrast-to-noise ratio over the matched B-mode images. The concept of SLSC imaging is then extended to matrix arrays, and the first in vivo demonstration of volumetric SLSC imaging on a clinical ultrasound system is presented. The effective suppression of clutter via volumetric SLSC imaging indicates it could potentially compensate for the low sensitivity associated with most commercial matrix arrays. The rest of the dissertation assesses image degradation due to elements blocked by ribs in a transthoracic scan. A method to detect the blocked elements is demonstrated using simulated, ex vivo, and in vivo data from the fully-sampled 2-D apertures. The results show that turning off the blocked elements both reduces the near-field clutter and improves visibility of anechoic/hypoechoic targets. Most importantly, the ex vivo data from large synthetic apertures indicates that the adaptive weighing of the non-blocked elements can recover the loss of focus quality due to periodic rib structure, allowing large apertures to realize their full resolution potential in transthoracic ultrasound.

  20. Experimental Demonstration of Adaptive Infrared Multispectral Imaging using Plasmonic Filter Array

    NASA Astrophysics Data System (ADS)

    Jang, Woo-Yong; Ku, Zahyun; Jeon, Jiyeon; Kim, Jun Oh; Lee, Sang Jun; Park, James; Noyola, Michael J.; Urbas, Augustine

    2016-10-01

    In our previous theoretical study, we performed target detection using a plasmonic sensor array incorporating the data-processing technique termed “algorithmic spectrometry”. We achieved the reconstruction of a target spectrum by extracting intensity at multiple wavelengths with high resolution from the image data obtained from the plasmonic array. The ultimate goal is to develop a full-scale focal plane array with a plasmonic opto-coupler in order to move towards the next generation of versatile infrared cameras. To this end, and as an intermediate step, this paper reports the experimental demonstration of adaptive multispectral imagery using fabricated plasmonic spectral filter arrays and proposed target detection scenarios. Each plasmonic filter was designed using periodic circular holes perforated through a gold layer, and an enhanced target detection strategy was proposed to refine the original spectrometry concept for spatial and spectral computation of the data measured from the plasmonic array. Both the spectrum of blackbody radiation and a metal ring object at multiple wavelengths were successfully reconstructed using the weighted superposition of plasmonic output images as specified in the proposed detection strategy. In addition, plasmonic filter arrays were theoretically tested on a target at extremely high temperature as a challenging scenario for the detection scheme.

  1. Experimental Demonstration of Adaptive Infrared Multispectral Imaging using Plasmonic Filter Array.

    PubMed

    Jang, Woo-Yong; Ku, Zahyun; Jeon, Jiyeon; Kim, Jun Oh; Lee, Sang Jun; Park, James; Noyola, Michael J; Urbas, Augustine

    2016-10-10

    In our previous theoretical study, we performed target detection using a plasmonic sensor array incorporating the data-processing technique termed "algorithmic spectrometry". We achieved the reconstruction of a target spectrum by extracting intensity at multiple wavelengths with high resolution from the image data obtained from the plasmonic array. The ultimate goal is to develop a full-scale focal plane array with a plasmonic opto-coupler in order to move towards the next generation of versatile infrared cameras. To this end, and as an intermediate step, this paper reports the experimental demonstration of adaptive multispectral imagery using fabricated plasmonic spectral filter arrays and proposed target detection scenarios. Each plasmonic filter was designed using periodic circular holes perforated through a gold layer, and an enhanced target detection strategy was proposed to refine the original spectrometry concept for spatial and spectral computation of the data measured from the plasmonic array. Both the spectrum of blackbody radiation and a metal ring object at multiple wavelengths were successfully reconstructed using the weighted superposition of plasmonic output images as specified in the proposed detection strategy. In addition, plasmonic filter arrays were theoretically tested on a target at extremely high temperature as a challenging scenario for the detection scheme.

  2. Experimental Demonstration of Adaptive Infrared Multispectral Imaging using Plasmonic Filter Array

    PubMed Central

    Jang, Woo-Yong; Ku, Zahyun; Jeon, Jiyeon; Kim, Jun Oh; Lee, Sang Jun; Park, James; Noyola, Michael J.; Urbas, Augustine

    2016-01-01

    In our previous theoretical study, we performed target detection using a plasmonic sensor array incorporating the data-processing technique termed “algorithmic spectrometry”. We achieved the reconstruction of a target spectrum by extracting intensity at multiple wavelengths with high resolution from the image data obtained from the plasmonic array. The ultimate goal is to develop a full-scale focal plane array with a plasmonic opto-coupler in order to move towards the next generation of versatile infrared cameras. To this end, and as an intermediate step, this paper reports the experimental demonstration of adaptive multispectral imagery using fabricated plasmonic spectral filter arrays and proposed target detection scenarios. Each plasmonic filter was designed using periodic circular holes perforated through a gold layer, and an enhanced target detection strategy was proposed to refine the original spectrometry concept for spatial and spectral computation of the data measured from the plasmonic array. Both the spectrum of blackbody radiation and a metal ring object at multiple wavelengths were successfully reconstructed using the weighted superposition of plasmonic output images as specified in the proposed detection strategy. In addition, plasmonic filter arrays were theoretically tested on a target at extremely high temperature as a challenging scenario for the detection scheme. PMID:27721506

  3. Design of area array CCD image acquisition and display system based on FPGA

    NASA Astrophysics Data System (ADS)

    Li, Lei; Zhang, Ning; Li, Tianting; Pan, Yue; Dai, Yuming

    2014-09-01

    With the development of science and technology, CCD(Charge-coupled Device) has been widely applied in various fields and plays an important role in the modern sensing system, therefore researching a real-time image acquisition and display plan based on CCD device has great significance. This paper introduces an image data acquisition and display system of area array CCD based on FPGA. Several key technical challenges and problems of the system have also been analyzed and followed solutions put forward .The FPGA works as the core processing unit in the system that controls the integral time sequence .The ICX285AL area array CCD image sensor produced by SONY Corporation has been used in the system. The FPGA works to complete the driver of the area array CCD, then analog front end (AFE) processes the signal of the CCD image, including amplification, filtering, noise elimination, CDS correlation double sampling, etc. AD9945 produced by ADI Corporation to convert analog signal to digital signal. Developed Camera Link high-speed data transmission circuit, and completed the PC-end software design of the image acquisition, and realized the real-time display of images. The result through practical testing indicates that the system in the image acquisition and control is stable and reliable, and the indicators meet the actual project requirements.

  4. Two-dimensional angular filter array for angular domain imaging with 3D printed angular filters

    NASA Astrophysics Data System (ADS)

    Ng, Eldon; Carson, Jeffrey J. L.

    2013-02-01

    Angular Domain Imaging (ADI) is a technique that is capable of generating two dimensional shadowgrams of attenuating targets embedded in a scattering medium. In ADI, an angular filter array (AFA) is positioned between the sample and the detector to distinguish between quasi-ballistic photons and scattered photons. An AFA is a series of micro-channels with a high aspect ratio. Previous AFAs from our group were constructed by micro-machining the micro-channels into a silicon wafer, limiting the imaging area to a one dimensional line. Two dimensional images were acquired via scanning. The objective of this work was to extend the AFA design to two dimensions to allow for two dimensional imaging with minimal scanning. The second objective of this work was to perform an initial characterization of the imaging capabilities of the 2D AFA. Our approach was to use rapid 3D prototyping techniques to generate an array of micro-channels. The imaging capabilities were then evaluated by imaging a 0.9 mm graphite rod submerged in a scattering media. Contrast was observed to improve when a second angular filter array was placed in front of the sample to mask the incoming light.

  5. Volumetric elasticity imaging with a 2-D CMUT array.

    PubMed

    Fisher, Ted G; Hall, Timothy J; Panda, Satchi; Richards, Michael S; Barbone, Paul E; Jiang, Jingfeng; Resnick, Jeff; Barnes, Steve

    2010-06-01

    This article reports the use of a two-dimensional (2-D) capacitive micro-machined ultrasound transducer (CMUT) to acquire radio-frequency (RF) echo data from relatively large volumes of a simple ultrasound phantom to compare three-dimensional (3-D) elasticity imaging methods. Typical 2-D motion tracking for elasticity image formation was compared with three different methods of 3-D motion tracking, with sum-squared difference (SSD) used as the similarity measure. Differences among the algorithms were the degree to which they tracked elevational motion: not at all (2-D search), planar search, combination of multiple planes and plane independent guided search. The cross-correlation between the predeformation and motion-compensated postdeformation RF echo fields was used to quantify motion tracking accuracy. The lesion contrast-to-noise ratio was used to quantify image quality. Tracking accuracy and strain image quality generally improved with increased tracking sophistication. When used as input for a 3-D modulus reconstruction, high quality 3-D displacement estimates yielded accurate and low noise modulus reconstruction.

  6. Volumetric Elasticity Imaging with a 2D CMUT Array

    PubMed Central

    Fisher, Ted G.; Hall, Timothy J.; Panda, Satchi; Richards, Michael S.; Barbone, Paul E.; Jiang, Jingfeng; Resnick, Jeff; Barnes, Steve

    2010-01-01

    This paper reports the use of a two-dimensional (2D) capacitive micro-machined ultrasound transducer (CMUT) to acquire radio frequency (RF) echo data from relatively large volumes of a simple ultrasound phantom to compare 3D elasticity imaging methods. Typical 2D motion tracking for elasticity image formation was compared to three different methods of 3D motion tracking, with sum-squared difference (SSD) used as the similarity measure. Differences among the algorithms were the degree to which they tracked elevational motion: not at all (2D search), planar search, combination of multiple planes, and plane independent guided search. The cross correlation between the pre-deformation and motion-compensated post-deformation RF echo fields was used to quantify motion tracking accuracy. The lesion contrast-to-noise ratio was used to quantify image quality. Tracking accuracy and strain image quality generally improved with increased tracking sophistication. When used as input for a 3D modulus reconstruction, high quality 3D displacement estimates yielded accurate and low noise modulus reconstruction. PMID:20510188

  7. An MF/HF radio array for radio and radar imaging of the ionosphere

    NASA Astrophysics Data System (ADS)

    Isham, Brett; Gustavsson, Bjorn; Belyey, Vasyl; Bullett, Terrence

    2016-07-01

    The Aguadilla Radio Array will be installed at the Interamerican University Aguadilla Campus, located in northwestern Puerto Rico. The array is intended for broad-band medium and high-frequency (MF/HF, roughly 2 to 25 MHz) radio and bistatic radar observations of the ionosphere. The main array consists of 20 antenna elements, arranged in a semi-random pattern providing a good distribution of baseline vectors, with 6-meter minimum spacing to eliminate spacial aliasing. A relocatable 6-element array is also being developed, in which each element consists of a crossed pair of active electric dipoles and all associated electronics for phase-coherent radio measurements. A primary scientific goal of the array is to create images of the region of ionospheric radio emissions stimulated by the new Arecibo Observatory high-power high-frequency radio transmitter. A second primary goal is the study of ionospheric structure and dynamics via coherent radar imaging of the ionosphere in collaboration with the University of Colorado / NOAA Versatile Interferometric Pulsed Ionospheric Radar (VIPIR), located at the USGS San Juan Observatory in Cayey, Puerto Rico. In addition to ionospheric research in collaboration with the Cayey and Arecibo Observatories, the goals of the project include the development of radio sounding, polarization, interferometry, and imaging techniques, and training of students at the university and high school levels.

  8. Simulation verification of SNR and parallel imaging improvements by ICE-decoupled loop array in MRI.

    PubMed

    Yan, Xinqiang; Cao, Zhipeng; Zhang, Xiaoliang

    2016-04-01

    Transmit/receive L/C loop arrays with the induced current elimination (ICE) or magnetic wall decoupling method has shown high signal-to-noise (SNR) and excellent parallel imaging ability for MR imaging at ultrahigh fields, e.g., 7 T. In this study, we aim to numerically analyze the performance of an eight-channel ICE-decoupled loop array at 7 T. Three dimensional (3-D) electromagnetic (EM) and radiofrequency (RF) circuit co-simulation approach was employed. The values of all capacitors were obtained by optimizing the S-parameters of all coil elements. The EM simulation accurately modeled the coil structure, the phantom and the excitation. All coil elements were well matched to 50 ohm and the isolation between any two coil elements was better -15 dB. The simulated S parameters were exactly similar with the experimental results, indicating the simulation results were reliable. Compared with the conventional capacitively decoupled array, the ICE-decoupled array had higher sensitivity at the peripheral areas of the image subjects due to the shielding effect of the decoupling loops. The increased receive sensitivity resulted in an improvement of signal intensity and SNR for the ICE-decoupled array.

  9. Arrayed liquid crystal microlens based on graphene electrode for imaging application

    NASA Astrophysics Data System (ADS)

    Hu, Wei; Chen, Cheng; Wu, Yong; Luo, Jun; Lei, Yu; Tong, Qing; Zhang, Xinyu; Xie, Changsheng

    2015-10-01

    In this paper, an arrayed liquid crystal (LC) microlens (ALCM) based on graphene electrode instead of common indium tin oxide (ITO) electrode material is designed and fabricated, and the corresponding testing results have been obtained and presented. The graphene film used as patterned electrode in the project is grown by chemical vapor deposition (CVD) over copper foils, which demonstrate the properties of low sheet resistance and high transmittance of more than 90% in current stage. The key fabrication of the arrayed LC microlens based on graphene electrode includes the graphene transfering, ultraviolet lithography, ICP etching, liquid crystalline polymer encapsulation, etc. In the test of the arrayed LC microlens, the point spread functions (PSF) of incident laser beams with different wavelengths, such as red laser of ~600nm wavelength, and green laser of ~532nm wavelength, have been obtained. In addition, the arrayed LC microlenses are also used in visible light imaging. During the imaging tests, each microlens in the arrayed LC microlens can perform imaging process, independently.

  10. Non-destructive evaluation of adhesive layer using a planar array capacitive imaging technology

    NASA Astrophysics Data System (ADS)

    Zhang, Yuyan; Zhao, Limei; Wen, Yintang; Sun, Dongtao

    2016-04-01

    The thermal protection materials for aircraft are usually assembled on the substrate surface by means of adhesion agent. It is very necessary to evaluate the interface bonding quality which has great influence on heat preservation performance. At present, there is still no relatively satisfactory and reliable method for defect detection of cohesive coating. Planar array electrical capacitance tomography (ECT) is a suitable non-invasive imaging technique when there is only limited access to the targeted object. This research aims to investigate the feasibility of using planar array electrical capacitive tomography for bondline defect detection. In this paper, a planar array ECT system is developed consist of a planar array sensor of 12 electrodes, a capacitance acquisition system and image reconstruction software. The sensor development, simulation of sensitivity map, practical application and imaging reconstruction are discussed. A series of specimens of thermal protection material with man-made defects are tested by the proposed planar array ECT system. The experimental results show that the defect in cohesive coating can be effectively detected and the minimum size can be detected is 10mm×10mm.

  11. Image reconstruction from phased-array data based on multichannel blind deconvolution.

    PubMed

    She, Huajun; Chen, Rong-Rong; Liang, Dong; Chang, Yuchou; Ying, Leslie

    2015-11-01

    In this paper we consider image reconstruction from fully sampled multichannel phased array MRI data without knowledge of the coil sensitivities. To overcome the non-uniformity of the conventional sum-of-square reconstruction, a new framework based on multichannel blind deconvolution (MBD) is developed for joint estimation of the image function and the sensitivity functions in image domain. The proposed approach addresses the non-uniqueness of the MBD problem by exploiting the smoothness of both functions in the image domain through regularization. Results using simulation, phantom and in vivo experiments demonstrate that the reconstructions by the proposed algorithm are more uniform than those by the existing methods.

  12. Millimeter-wave imaging with frequency scanning antenna and optical arrayed waveguide gratings

    NASA Astrophysics Data System (ADS)

    He, Yuntao; Yu, Guoxin; Fu, Xinyu; Jiang, Yuesong

    2012-12-01

    The principle of a novel passive millimeter-wave (MMW) imaging method using frequency scanning antenna (FSA) and arrayed waveguide grating (AWG) is analyzed theoretically. The imaging processes are divided to three stages and discussed respectively. Then the FSA with 33~ 43GHz frequency scanning range is designed carefully with a field of view of +/-25°for the MMW imaging system. An AWG of 1×24 is then simply designed with a channel spacing of 0.5GHz. The designing and simulating demonstrated the feasibility to build such an imaging system which is progressing.

  13. Hybrid lightweight X-ray optics for half arcsecond imaging

    NASA Astrophysics Data System (ADS)

    Reid, Paul

    This proposal is for the development of grazing incidence optics suitable to meet the 0.5 arcsec imaging and 2.3 square meter effective area requirements of the X-ray Surveyor mission concept, currently under study by NASA. Our approach is to combine two promising technologies, as yet individually unproven at the 0.5 arcsec level, into a hybrid mirror approach. The two technologies are thin piezoelectric film adjustable optics under development at SAO and PSU, and differential deposition under development at NASA MSFC. These technologies are complementary: adjustable optics are best suited to fixing low spatial frequency errors due to piezoelectric cell size limitations, and differential deposition is best suited for fixing mid-spatial frequency errors so as to limit the amount of material that must be deposited. Thus, the combination of the two techniques extends the bandwidth of figure errors that can be corrected beyond what it was for either individual technique. Both technologies will be applied to fabricate Wolter-I mirror segment from single thermally formed glass substrates. This work is directed at mirror segments only (not full shells), as we believe segments are the most appropriate for developing the 3 m diameter X-ray Surveyor high resolution mirror. In this program we will extend differential deposition to segment surfaces (from line profiles), investigate the most realistic error bandwidths for each technology, and determine the impacts of one technologys processing steps on the other to find if there is an optimal order to combining the technologies. In addition, we will also conduct a conical/cylindrical mirror metrology "round-robin," to cross-calibrate the different cylindrical metrology to one another as a means of minimizing systematic errors. Finally, we will examine the balancing and compensating of mirror stress due to the various thin films employed (piezoelectric layer, differential deposition, X-ray reflecting layer(s)) with an eye to

  14. Optical Image Classification Using Optical/digital Hybrid Image Processing Systems.

    NASA Astrophysics Data System (ADS)

    Li, Xiaoyang

    1990-01-01

    Offering parallel and real-time operations, optical image classification is becoming a general technique in the solution of real-life image classification problems. This thesis investigates several algorithms for optical realization. Compared to other statistical pattern recognition algorithms, the Kittler-Young transform can provide more discriminative feature spaces for image classification. We shall apply the Kittler-Young transform to image classification and implement it on optical systems. A feature selection criterion is designed for the application of the Kittler -Young transform to image classification. The realizations of the Kittler-Young transform on both a joint transform correlator and a matrix multiplier are successively conducted. Experiments of applying this technique to two-category and three-category problems are demonstrated. To combine the advantages of the statistical pattern recognition algorithms and the neural network models, processes using the two methods are studied. The Karhunen-Loeve Hopfield model is developed for image classification. This model has significant improvement in the system capacity and the capability of using image structures for more discriminative classification processes. As another such hybrid process, we propose the feature extraction perceptron. The application of feature extraction techniques to the perceptron shortens its learning time. An improved activation function of neurons (dynamic activation function), its design and updating rule for fast learning process and high space-bandwidth product image classification are also proposed. We have shortened by two-thirds the learning time on the feature extraction perceptron as compared with the original perceptron. By using this architecture, we have shown that the classification performs better than both the Kittler-Young transform and the original perceptron.

  15. Graphene-based carbon-layered electrode array technology for neural imaging and optogenetic applications.

    PubMed

    Park, Dong-Wook; Schendel, Amelia A; Mikael, Solomon; Brodnick, Sarah K; Richner, Thomas J; Ness, Jared P; Hayat, Mohammed R; Atry, Farid; Frye, Seth T; Pashaie, Ramin; Thongpang, Sanitta; Ma, Zhenqiang; Williams, Justin C

    2014-10-20

    Neural micro-electrode arrays that are transparent over a broad wavelength spectrum from ultraviolet to infrared could allow for simultaneous electrophysiology and optical imaging, as well as optogenetic modulation of the underlying brain tissue. The long-term biocompatibility and reliability of neural micro-electrodes also require their mechanical flexibility and compliance with soft tissues. Here we present a graphene-based, carbon-layered electrode array (CLEAR) device, which can be implanted on the brain surface in rodents for high-resolution neurophysiological recording. We characterize optical transparency of the device at >90% transmission over the ultraviolet to infrared spectrum and demonstrate its utility through optical interface experiments that use this broad spectrum transparency. These include optogenetic activation of focal cortical areas directly beneath electrodes, in vivo imaging of the cortical vasculature via fluorescence microscopy and 3D optical coherence tomography. This study demonstrates an array of interfacing abilities of the CLEAR device and its utility for neural applications.

  16. A Topological Array Trigger for AGIS, the Advanced Gamma ray Imaging System

    SciTech Connect

    Krennrich, F.; Anderson, J.; Byrum, K.; Dawson, J.; Drake, G.; Haberichter, W.; Kreps, A.; Smith, A.; Buckley, J.; Krawczynski, H.; Imran, A.; Schroedter, M.

    2008-12-24

    Next generation ground based {gamma}-ray observatories such as AGIS{sup 1} and CTA{sup 2} are expected to cover a 1 km{sup 2} area with 50-100 imaging atmospheric Cherenkov telescopes. The stereoscopic view ol air showers using multiple view points raises the possibility to use a topological array trigger that adds substantial flexibility, new background suppression capabilities and a reduced energy threshold. In this paper we report on the concept and technical implementation of a fast topological trigger system, that makes use of real time image processing of individual camera patterns and their combination in a stereoscopic array analysis. A prototype system is currently under construction and we discuss the design and hardware of this topological array trigger system.

  17. Preliminary work of real-time ultrasound imaging system for 2-D array transducer.

    PubMed

    Li, Xu; Yang, Jiali; Ding, Mingyue; Yuchi, Ming

    2015-01-01

    Ultrasound (US) has emerged as a non-invasive imaging modality that can provide anatomical structure information in real time. To enable the experimental analysis of new 2-D array ultrasound beamforming methods, a pre-beamformed parallel raw data acquisition system was developed for 3-D data capture of 2D array transducer. The transducer interconnection adopted the row-column addressing (RCA) scheme, where the columns and rows were active in sequential for transmit and receive events, respectively. The DAQ system captured the raw data in parallel and the digitized data were fed through the field programmable gate array (FPGA) to implement the pre-beamforming. Finally, 3-D images were reconstructed through the devised platform in real-time.

  18. Hybrid Nanotrimers for Dual T1 and T2-Weighted Magnetic Resonance Imaging

    PubMed Central

    2015-01-01

    Development of multifunctional nanoparticle-based probes for dual T1- and T2-weighted magnetic resonance imaging (MRI) could allow us to image and diagnose the tumors or other abnormalities in an exceptionally accurate and reliable manner. In this study, by fusing distinct nanocrystals via solid-state interfaces, we built hybrid heteronanostructures to combine both T1 and T2- weighted contrast agents together for MRI with high accuracy and reliability. The resultant hybrid heterotrimers showed high stability in physiological conditions and could induce both simultaneous positive and negative contrast enhancements in MR images. Small animal positron emission tomography imaging study revealed that the hybrid heterostructures displayed favorable biodistribution and were suitable for in vivo imaging. Their potential as dual contrast agents for T1 and T2-weighted MRI was further demonstrated by in vitro and in vivo imaging and relaxivity measurements. PMID:25283972

  19. Frequency-domain photoacoustic phased array probe for biomedical imaging applications.

    PubMed

    Telenkov, Sergey; Alwi, Rudolf; Mandelis, Andreas; Worthington, Arthur

    2011-12-01

    We report the development of a frequency-domain biomedical photoacoustic imaging system that utilizes a continuous-wave laser source with a custom intensity modulation pattern, ultrasonic phased array for signal detection, and processing coupled with a beam-forming algorithm for reconstruction of photoacoustic correlation images. Sensitivity to optical contrast was demonstrated using tissue-mimicking phantoms and in-vivo tissue samples.

  20. Multispectral X-Ray Imaging With A Pinhole Array And A Flat Bragg Mirror

    SciTech Connect

    Koch, J A; Barbee, Jr., T W; Izumi, N; Tommasini, R; Welser, L A; Mancini, R C; Marshall, F J

    2005-03-17

    We describe a multiple monochromatic x-ray imager designed for implosion experiments. This instrument uses an array of pinholes in front of a flat multilayered Bragg mirror to provide many individual quasi-monochromatic x-ray pinhole images spread over a wide spectral range. We discuss design constraints and optimizations, and we discuss the specific details of the instrument we have used to obtain temperature and density maps of implosion plasmas.

  1. Doped carbon nanostructure field emitter arrays for infrared imaging

    DOEpatents

    Korsah, Kofi [Knoxville, TN; Baylor, Larry R [Farragut, TN; Caughman, John B [Oak Ridge, TN; Kisner, Roger A [Knoxville, TN; Rack, Philip D [Knoxville, TN; Ivanov, Ilia N [Knoxville, TN

    2009-10-27

    An infrared imaging device and method for making infrared detector(s) having at least one anode, at least one cathode with a substrate electrically connected to a plurality of doped carbon nanostructures; and bias circuitry for applying an electric field between the anode and the cathode such that when infrared photons are adsorbed by the nanostructures the emitted field current is modulated. The detectors can be doped with cesium to lower the work function.

  2. A microfluidic-based hybrid SPR/molecular imaging biosensor for the multiplexed detection of foodborne pathogens

    NASA Astrophysics Data System (ADS)

    Zordan, Michael D.; Grafton, Meggie M. G.; Acharya, Ghanashyam; Reece, Lisa M.; Aronson, Arthur I.; Park, Kinam; Leary, James F.

    2009-02-01

    It is important to screen our food supply for pathogen contaminations. Current methods to screen for bacterial contamination involve using costly reagents such as antibodies or PCR reagents or time-costly growth in cultures. There is need for portable, real-time, multiplex pathogen detection technology that can predict the safety of food where it is produced or distributed. Surface plasmon resonance (SPR) imaging is a sensitive, label-free method that can detect the binding of an analyte to a surface due to changes in refractive index that occur upon binding. It can be used for label-free detection of the presence of potential pathogens. Simultaneous fluorescence molecular imaging on the other side of the biochip can be used to ascertain pathogen status or functional state which may affect its potential danger to humans or animals. We are designing and testing hybrid microfluidic biochips to detect multiple pathogens using a combination of SPRI and fluorescence imaging. The device consists of an array of gold spots, each functionalized with a peptide targeting a specific pathogen. This peptide biosensor array is enclosed by a PDMS microfluidic flow chamber that delivers a magnetically concentrated sample to be tested. An SPR image is taken from the bottom of the biochip. Image analysis is used to quantify the amount of pathogen (both live and dead) bound to each spot. Since PDMS is very transmissive to visible light, an epi-fluorescence image is taken from the top of the biochip. Fluorescence imaging determines the live:dead ratio of each pathogen using an inexpensive SYTO 9(R)-Propidium Iodide assay. The volume of sample that the biochip can analyze is small, so possible pathogens are pre-concentrated using immunomagnetic separation. Functionalized magnetic particles are bound to pathogens present in the sample, and a magnet is used to separate them from the bulk fluid.

  3. Hybrid prestack migration of scattered teleseismic waves and local earthquake sequences for the imaging of source fault and subducting slab

    NASA Astrophysics Data System (ADS)

    Abe, S.; Sato, H.; Kurashimo, E.; Hirata, N.; Iwasaki, T.; Kawanaka, T.

    2011-12-01

    The deep geometry of active faults and the mid-crustal detachment at the base of seismogenic layer is important for understanding active tectonic process and accessing the risk of destructive earthquakes. The detailed image of source fault and subducting slab have been delineated by the controlled-source reflection profiling with the dense array of wide-angle seismic line through the combination of telemetry and independent recording system. Over the past decade, the deployment of a dense seismic array of portable broadband seismometers with 0.5-1.0km station interval has presented a number of imaging opportunities using scattered teleseismic wave and local-earthquake sequences, and provided the complementary data for the structural interpretation of lithosphere beneath the seismogenic layer. Passive seismic imaging methods using scattered teleseismic wave and local-earthquake sequences include receiver function analysis (RFA), interferometric seismic imaging (ISI) and reverse-VSP approach (RVA). We summarized the potential applicability of these imaging methods, regarding migration artifacts due to irregular spatial sampling, prerequisite for azimuth distribution, removal of source-time function and error estimation of origin time and focal depth. Further, we discussed spatial and temporal resolution of seismic profiles obtained by these imaging methods based on the evaluation of tuning thickness and second Fresnel zone. Synthetic seismograms simulated by the elastic pseudospectral method for a simple 2.5D crustal model are given to investigate the application of RFA, ISI and RVA approach. The numerical modeling results demonstrate that migration artifacts and spurious events due to irregular passive-source geometry can be reduced by the multi-mode imaging of various forward and backward scattered phases using hybrid application of ray-theoretical RFA, ISI and RVA.

  4. Joint demosaicking and integer-ratio downsampling algorithm for color filter array image

    NASA Astrophysics Data System (ADS)

    Lee, Sangyoon; Kang, Moon Gi

    2015-03-01

    This paper presents a joint demosacking and integer-ratio downsampling algorithm for color filter array (CFA) images. Color demosaicking is a necessary part of image signal processing to obtain full color image for digital image recording system using single sensor. Also, such as mobile devices, the obtained image from sensor has to be downsampled to be display because the resolution of display is smaller than that of image. The conventional method is "Demosaicking first and downsampling later". However, this procedure requires a significant hardware resources and computational cost. In this paper, we proposed a method in which demosaicking and downsampling are working simultaneously. We analyze the Bayer CFA image in frequency domain, and then joint demosaicking and downsampling with integer-ratio scheme based on signal decomposition of luma and chrominance components. Experimental results show that the proposed method produces the high quality performance with much lower com putational cost and less hardware resources.

  5. Chemical imaging of cotton fibers using an infrared microscope and a focal-plane array detector

    Technology Transfer Automated Retrieval System (TEKTRAN)

    In this presentation, the chemical imaging of cotton fibers with an infrared microscope and a Focal-Plane Array (FPA) detector will be discussed. Infrared spectroscopy can provide us with information on the structure and quality of cotton fibers. In addition, FPA detectors allow for simultaneous spe...

  6. Clutter noise reduction for phased array imaging using frequency-spatial polarity coherence

    NASA Astrophysics Data System (ADS)

    Gongzhang, Rui; Gachagan, Anthony; Xiao, Bo

    2015-03-01

    A number of materials used in industry exhibit highly-scattering properties which can reduce the performance of conventional ultrasonic NDE approaches. Moving Bandwidth Polarity Thresholding (MBPT) is a robust frequency diversity based algorithm for scatter noise reduction in single A-scan waveforms, using sign coherence across a range of frequency bands to reduce grain noise and improve Signal to Noise Ratio. Importantly, for this approach to be extended to array applications, spatial variation of noise characteristics must also be considered. This paper presents a new spatial-frequency diversity based algorithm for array imaging, extended from MBPT. Each A-scan in the full matrix capture array dataset is partitioned into a serial of overlapped frequency bands and then undergoes polarity thresholding to generate sign-only coefficients indicating possible flaw locations within each selected band. These coefficients are synthesized to form a coefficient matrix using a delay and sum approach in each frequency band. Matrices produced across the frequency bands are then summed to generate a weighting matrix, which can be applied on any conventional image. A 5MHz linear array has been used to acquire data from both austenitic steel and high nickel alloy (HNA) samples to validate the proposed algorithm. Background noise is significantly suppressed for both samples after applying this approach. Importantly, three side drilled holes and the back wall of the HNA sample are clearly enhanced in the processed image, with a mean 133% Contrast to Noise Ratio improvement when compared to a conventional TFM image.

  7. Efficient Data Capture and Post-Processing for Real-Time Imaging Using AN Ultrasonic Array

    NASA Astrophysics Data System (ADS)

    Moreau, L.; Hunter, A. J.; Drinkwater, B. W.; Wilcox, P. D.

    2010-02-01

    Over the past few years, ultrasonic phased arrays have shown good potential for nondestructive testing (NDT), thanks to high resolution imaging algorithms. Many algorithms are based on the full matrix capture, obtained by firing each element of an ultrasonic array independently, and collecting the data with all elements. Because of the finite sound velocity in the specimen, two consecutive firings must be separated by a minimum time interval. Therefore, more array elements require longer data acquisition times. Moreover, if the array has N elements, then the full matrix contains N2 temporal signals to be processed. Because of the limited calculation speed of current computers, a large matrix of data can result in long post-processing times. In an industrial context where real-time imaging is desirable, it is crucial to reduce acquisition and/or post-processing times. This paper investigates methods designed to reduce acquisition and post-processing times for the total focusing method and wavenumber imaging algorithms. Limited transmission cycles are used to reduce data capture and post-processing. Post-processing times are further reduced by demodulating the data to temporal baseband frequencies. Results are presented so that a compromise can be made between acquisition time, post-processing time and image quality.

  8. Airborne Linear Array Image Geometric Rectification Method Based on Unequal Segmentation

    NASA Astrophysics Data System (ADS)

    Li, J. M.; Li, C. R.; Zhou, M.; Hu, J.; Yang, C. M.

    2016-06-01

    As the linear array sensor such as multispectral and hyperspectral sensor has great potential in disaster monitoring and geological survey, the quality of the image geometric rectification should be guaranteed. Different from the geometric rectification of airborne planar array images or multi linear array images, exterior orientation elements need to be determined for each scan line of single linear array images. Internal distortion persists after applying GPS/IMU data directly to geometrical rectification. Straight lines may be curving and jagged. Straight line feature -based geometrical rectification algorithm was applied to solve this problem, whereby the exterior orientation elements were fitted by piecewise polynomial and evaluated with the straight line feature as constraint. However, atmospheric turbulence during the flight is unstable, equal piecewise can hardly provide good fitting, resulting in limited precision improvement of geometric rectification or, in a worse case, the iteration cannot converge. To solve this problem, drawing on dynamic programming ideas, unequal segmentation of line feature-based geometric rectification method is developed. The angle elements fitting error is minimized to determine the optimum boundary. Then the exterior orientation elements of each segment are fitted and evaluated with the straight line feature as constraint. The result indicates that the algorithm is effective in improving the precision of geometric rectification.

  9. Design of high-T[sub c] superconducting bolometers for a far infrared imaging array

    SciTech Connect

    Verghese, S.; Richards, P.L. ); Fork, D.K. ); Char, K. ); Geballe, T.H. . Dept. of Applied Physics)

    1992-08-01

    The design of high-[Tc] superconducting bolometers for use in a far infrared imaging array from wavelengths 30--100[mu]m is discussed. Measurements of the voltage noise in thin films of YBa[sub 2]CU[sub 3]O[sub 7-[var sigma

  10. Mercuric iodide room-temperature array detectors for gamma-ray imaging

    SciTech Connect

    Patt, B.

    1994-11-15

    Significant progress has been made recently in the development of mercuric iodide detector arrays for gamma-ray imaging, making real the possibility of constructing high-performance small, light-weight, portable gamma-ray imaging systems. New techniques have been applied in detector fabrication and then low noise electronics which have produced pixel arrays with high-energy resolution, high spatial resolution, high gamma stopping efficiency. Measurements of the energy resolution capability have been made on a 19-element protypical array. Pixel energy resolutions of 2.98% fwhm and 3.88% fwhm were obtained at 59 keV (241-Am) and 140-keV (99m-Tc), respectively. The pixel spectra for a 14-element section of the data is shown together with the composition of the overlapped individual pixel spectra. These techniques are now being applied to fabricate much larger arrays with thousands of pixels. Extension of these principles to imaging scenarios involving gamma-ray energies up to several hundred keV is also possible. This would enable imaging of the 208 keV and 375-414 keV 239-Pu and 240-Pu structures, as well as the 186 keV line of 235-U.

  11. Linear array implementation of the EM algorithm for PET image reconstruction

    SciTech Connect

    Rajan, K.; Patnaik, L.M.; Ramakrishna, J.

    1995-08-01

    The PET image reconstruction based on the EM algorithm has several attractive advantages over the conventional convolution back projection algorithms. However, the PET image reconstruction based on the EM algorithm is computationally burdensome for today`s single processor systems. In addition, a large memory is required for the storage of the image, projection data, and the probability matrix. Since the computations are easily divided into tasks executable in parallel, multiprocessor configurations are the ideal choice for fast execution of the EM algorithms. In tis study, the authors attempt to overcome these two problems by parallelizing the EM algorithm on a multiprocessor systems. The parallel EM algorithm on a linear array topology using the commercially available fast floating point digital signal processor (DSP) chips as the processing elements (PE`s) has been implemented. The performance of the EM algorithm on a 386/387 machine, IBM 6000 RISC workstation, and on the linear array system is discussed and compared. The results show that the computational speed performance of a linear array using 8 DSP chips as PE`s executing the EM image reconstruction algorithm is about 15.5 times better than that of the IBM 6000 RISC workstation. The novelty of the scheme is its simplicity. The linear array topology is expandable with a larger number of PE`s. The architecture is not dependant on the DSP chip chosen, and the substitution of the latest DSP chip is straightforward and could yield better speed performance.

  12. Computer simulation of the effects of a distributed array antenna on synthetic aperture radar images

    NASA Technical Reports Server (NTRS)

    Estes, J. M.

    1985-01-01

    The ARL:UT orbital SAR simulation has been upgraded to use three-dimensional antenna gain patterns. This report describes the modifications and presents quantitative image analyses of a simulation using antenna patterns generated from the modeling of a distributed array antenna.

  13. Demonstration of nanoimprinted hyperlens array for high-throughput sub-diffraction imaging

    PubMed Central

    Byun, Minsueop; Lee, Dasol; Kim, Minkyung; Kim, Yangdoo; Kim, Kwan; Ok, Jong G.; Rho, Junsuk; Lee, Heon

    2017-01-01

    Overcoming the resolution limit of conventional optics is regarded as the most important issue in optical imaging science and technology. Although hyperlenses, super-resolution imaging devices based on highly anisotropic dispersion relations that allow the access of high-wavevector components, have recently achieved far-field sub-diffraction imaging in real-time, the previously demonstrated devices have suffered from the extreme difficulties of both the fabrication process and the non-artificial objects placement. This results in restrictions on the practical applications of the hyperlens devices. While implementing large-scale hyperlens arrays in conventional microscopy is desirable to solve such issues, it has not been feasible to fabricate such large-scale hyperlens array with the previously used nanofabrication methods. Here, we suggest a scalable and reliable fabrication process of a large-scale hyperlens device based on direct pattern transfer techniques. We fabricate a 5 cm × 5 cm size hyperlenses array and experimentally demonstrate that it can resolve sub-diffraction features down to 160 nm under 410 nm wavelength visible light. The array-based hyperlens device will provide a simple solution for much more practical far-field and real-time super-resolution imaging which can be widely used in optics, biology, medical science, nanotechnology and other closely related interdisciplinary fields. PMID:28393906

  14. Male with mosaicism for supernumerary ring X chromosome: analysis of phenotype and characterization of genotype using array comparative genome hybridization.

    PubMed

    Baker, Peter R; Tsai, Anne Chun-Hui; Springer, Michelle; Swisshelm, Karen; March, Jennifer; Brown, Kathleen; Bellus, Gary

    2010-09-01

    Supernumerary, derivative, and ring X chromosomes are relatively common in Turner syndrome females but have been reported rarely in males. To date, less than 10 cases have been published, of which only 2 have been partially characterized in defining the breakpoints and genetic content of the derivative X chromosome. We describe a male with mosaicism for a supernumerary X chromosome (46,XY/47,XY, r(X)) who has multiple congenital anomalies, including features of craniofrontonasal dysplasia (Mendelian Inheritance in Man 304110) and the presence of ectopic female reproductive organs. Using comparative genomic hybridization array mapping, we determined that the derivative X is composed of a 24-Mb fragment that contains the regions Xp11.3 through Xq13.1 and lacks the XIST gene. This is the first report to describe a detailed molecular characterization of a ring X chromosome in a male by comparative genomic hybridization array analysis. We compare the clinical and molecular findings in this patient to other 46,XY, r(X) patients reported in the literature and discuss the potential role of disomy for known genes contained on the ring X chromosome.

  15. Effects of chromosomal variations on pharmacokinetic activity of zolpidem in healthy volunteers: an array-based comparative genomic hybridization study.

    PubMed

    Moon, Ho-Jin; Choi, Jin Soo; Park, E-Jin; Kang, Chin-Yang; Jeon, Yang-Whan; Lee, Kweon-Haeng; Rha, Hyoung Kyun; Han, Sang-Ick

    2007-05-18

    Zolpidem has been known as a very safe and effective hypnotic drug used to treat a variety of patients with insomnia. Even though the same dose of the medicine is administered to each patient, the blood level of zolpidem and the time required to obtain peak concentration are not consistent among different people. We evaluated the relationship between the peak concentrations of zolpidem and chromosomal imbalances using a high-resolution genome-wide array-based comparative genomic hybridization (CGH) in 16 healthy volunteers in order to detect the genetic factors underlying the variations. The present study showed that chromosomal losses were detected in the 4q35.2, 9p13.1 and 9p12 regions, and those gains were indicated in the 2p14, 11q13.4 and 15q11.2 regions. The abnormal regions were confirmed by fluorescence in situ hybridization (FISH) and real-time PCR. It is suggested that array-CGH analysis may be used as a measure for pharmacogenomic applications in the patients with insomnia and for further exploration of candidate genomic regions implicated in sleep disturbances.

  16. Wideband 2-D Array Design Optimization With Fabrication Constraints for 3-D US Imaging.

    PubMed

    Roux, Emmanuel; Ramalli, Alessandro; Liebgott, Herve; Cachard, Christian; Robini, Marc C; Tortoli, Piero

    2017-01-01

    Ultrasound (US) 2-D arrays are of increasing interest due to their electronic steering capability to investigate 3-D regions without requiring any probe movement. These arrays are typically populated by thousands of elements that, ideally, should be individually driven by the companion scanner. Since this is not convenient, the so-called microbeamforming methods, yielding a prebeamforming stage performed in the probe handle by suitable custom integrated circuits, have so far been implemented in a few commercial high-end scanners. A possible approach to implement relatively cheap and efficient 3-D US imaging systems is using 2-D sparse arrays in which a limited number of elements can be coupled to an equal number of independent transmit/receive channels. In order to obtain US beams with adequate characteristics all over the investigated volume, the layout of such arrays must be carefully designed. This paper provides guidelines to design, by using simulated annealing optimization, 2-D sparse arrays capable of fitting specific applications or fabrication/implementation constraints. In particular, an original energy function based on multidepth 3-D analysis of the beam pattern is also exploited. A tutorial example is given, addressed to find the N e elements that should be activated in a 2-D fully populated array to yield efficient acoustic radiating performance over the entire volume. The proposed method is applied to a 32 ×32 array centered at 3 MHz to select the 128, 192, and 256 elements that provide the best acoustic performance. It is shown that the 256-element optimized array yields sidelobe levels even lower (by 5.7 dB) than that of the reference 716-element circular and (by 10.3 dB) than that of the reference 1024-element array.

  17. Platinum nanoparticles-single-walled carbon nanotubes hybrid based chemiresistive sensor array for myoglobin detection

    NASA Astrophysics Data System (ADS)

    Sharma, Vikash; Puri, Nitin K.; Mulchandani, Ashok; Rajesh

    2016-03-01

    We examined the potential of platinum nanoparticles (PtNP) modified single-walled carbon nanotube (SWNT) hybrid chemiresistive sensor for detection of antigen myoglobin (Mb) in phosphate buffer saline. Protein antibody, Ab-Mb, was covalently immobilized through site specific binding on PtNP attached over SWNT. A concentration-dependent change in the source-drain current of the hybrid device was observed in the range of 0.1-1000 ng ml-1. The hybrid device response fitted well with the Hill-Langmuir equation with a maximum response of 111.14% and low dissociation constant value (K d = 19.98 ng ml-1), indicating high protein antigen binding affinity at hybrid nanostructure.

  18. Method for producing a hybridization of detector array and integrated circuit for readout

    NASA Technical Reports Server (NTRS)

    Fossum, Eric R. (Inventor); Grunthaner, Frank J. (Inventor)

    1993-01-01

    A process is explained for fabricating a detector array in a layer of semiconductor material on one substrate and an integrated readout circuit in a layer of semiconductor material on a separate substrate in order to select semiconductor material for optimum performance of each structure, such as GaAs for the detector array and Si for the integrated readout circuit. The detector array layer is lifted off its substrate, laminated on the metallized surface on the integrated surface, etched with reticulating channels to the surface of the integrated circuit, and provided with interconnections between the detector array pixels and the integrated readout circuit through the channels. The adhesive material for the lamination is selected to be chemically stable to provide electrical and thermal insulation and to provide stress release between the two structures fabricated in semiconductor materials that may have different coefficients of thermal expansion.

  19. Determination of the Pressure Equivalent Noise Signal of Vector Sensors in a Hybrid Array

    DTIC Science & Technology

    2012-12-01

    Electromagnetic Interference HDPE High Density Polyethylene LOFAR Low Frequency Analysis and Recording MRA Maximum Response Axis NPS Naval... amplitude and phase of the array channels relative to the central microphone and then implemented the beamformer in the frequency domain. Under anechoic...rigid clamps to the stand helps to damp out high frequency vibration induced noise signals. The relatively large aspect presented by the array in

  20. Engineered magnetic hybrid nanoparticles with enhanced relaxivity for tumor imaging.

    PubMed

    Aryal, Santosh; Key, Jaehong; Stigliano, Cinzia; Ananta, Jeyarama S; Zhong, Meng; Decuzzi, Paolo

    2013-10-01

    Clinically used contrast agents for magnetic resonance imaging (MRI) suffer by the lack of specificity; short circulation time; and insufficient relaxivity. Here, a one-step combinatorial approach is described for the synthesis of magnetic lipid-polymer (hybrid) nanoparticles (MHNPs) encapsulating 5 nm ultra-small super-paramagnetic iron oxide particles (USPIOs) and decorated with Gd(3+) ions. The MHNPs comprise a hydrophobic poly(lactic acid-co-glycolic acid) (PLGA) core, containing up to ~5% USPIOs (w/w), stabilized by lipid and polyethylene glycol (PEG). Gd(3+) ions are directly chelated to the external lipid monolayer. Three different nanoparticle configurations are presented including Gd(3+) chelates only (Gd-MHNPs); USPIOs only (Fe-MHNPs); and the combination thereof (MHNPs). All three MHNPs exhibit a hydrodynamic diameter of about 150 nm. The Gd-MHNPs present a longitudinal relaxivity (r1 = 12.95 ± 0.53 (mM s)(-1)) about four times larger than conventional Gd-based contrast agents (r1 = 3.4 (mM s)(-1)); MHNPs have a transversal relaxivity of r2 = 164.07 ± 7.0 (mM s)(-1), which is three to four times larger than most conventional systems (r2 ~ 50 (mM s)(-1)). In melanoma bearing mice, elemental analysis for Gd shows about 3% of the injected MHNPs accumulating in the tumor and 2% still circulating in the blood, at 24 h post-injection. In a clinical 3T MRI scanner, MHNPs provide significant contrast confirming the observed tumor deposition. This approach can also accommodate the co-loading of hydrophobic therapeutic compounds in the MHNP core, paving the way for theranostic systems.

  1. Hybrid anisotropic nanostructures for dual-modal cancer imaging and image-guided chemo-thermo therapies.

    PubMed

    Zhang, Ruiping; Cheng, Kai; Antaris, Alexander L; Ma, Xiaowei; Yang, Min; Ramakrishnan, Sindhuja; Liu, Guifeng; Lu, Alex; Dai, Hongjie; Tian, Mei; Cheng, Zhen

    2016-10-01

    The multimodality theranostic system, which can integrate two or more different therapeutic modalities and multimodal imaging agents into a nanoentity, shows great promising prospects for the cancer treatment. Herein, we developed an efficient and novel strategy to synthesize hybrid anisotropic nanoparticles (HANs) with intrinsic multimodal theranostic capability [chemotherapy, photothermal therapy, magnetic resonance imaging (MRI), and photoacoustic imaging (PAI)]. For the first time, under the guidance of MRI and PAI, the chemotherapy and thermotherapy induced by administration of multifunctional hybrid nanoprobes were applied simultaneously to the treatment of colon cancer-bearing mice in vivo.

  2. Investigation of multichannel phased array performance for fetal MR imaging on 1.5T clinical MR system.

    PubMed

    Li, Ye; Pang, Yong; Vigneron, Daniel; Glenn, Orit; Xu, Duan; Zhang, Xiaoliang

    2011-01-01

    Fetal MRI on 1.5T clinical scanner has been increasingly becoming a powerful imaging tool for studying fetal brain abnormalities in vivo. Due to limited availability of dedicated fetal phased arrays, commercial torso or cardiac phased arrays are routinely used for fetal scans, which are unable to provide optimized SNR and parallel imaging performance with a small number coil elements, and insufficient coverage and filling factor. This poses a demand for the investigation and development of dedicated and efficient radiofrequency (RF) hardware to improve fetal imaging. In this work, an investigational approach to simulate the performance of multichannel flexible phased arrays is proposed to find a better solution to fetal MR imaging. A 32 channel fetal array is presented to increase coil sensitivity, coverage and parallel imaging performance. The electromagnetic field distribution of each element of the fetal array is numerically simulated by using finite-difference time-domain (FDTD) method. The array performance, including B(1) coverage, parallel reconstructed images and artifact power, is then theoretically calculated and compared with the torso array. Study results show that the proposed array is capable of increasing B(1) field strength as well as sensitivity homogeneity in the entire area of uterus. This would ensure high quality imaging regardless of the location of the fetus in the uterus. In addition, the paralleling imaging performance of the proposed fetal array is validated by using artifact power comparison with torso array. These results demonstrate the feasibility of the 32 channel flexible array for fetal MR imaging at 1.5T.

  3. Application of linear array imaging techniques to the real-time inspection of airframe structures and substructures

    NASA Technical Reports Server (NTRS)

    Miller, James G.

    1995-01-01

    Development and application of linear array imaging technologies to address specific aging-aircraft inspection issues is described. Real-time video-taped images were obtained from an unmodified commercial linear-array medical scanner of specimens constructed to simulate typical types of flaws encountered in the inspection of aircraft structures. Results suggest that information regarding the characteristics, location, and interface properties of specific types of flaws in materials and structures may be obtained from the images acquired with a linear array. Furthermore, linear array imaging may offer the advantage of being able to compare 'good' regions with 'flawed' regions simultaneously, and in real time. Real-time imaging permits the inspector to obtain image information from various views and provides the opportunity for observing the effects of introducing specific interventions. Observation of an image in real-time can offer the operator the ability to 'interact' with the inspection process, thus providing new capabilities, and perhaps, new approaches to nondestructive inspections.

  4. Metal-organic framework derived hybrid Co3O4-carbon porous nanowire arrays as reversible oxygen evolution electrodes.

    PubMed

    Ma, Tian Yi; Dai, Sheng; Jaroniec, Mietek; Qiao, Shi Zhang

    2014-10-01

    Hybrid porous nanowire arrays composed of strongly interacting Co3O4 and carbon were prepared by a facile carbonization of the metal-organic framework grown on Cu foil. The resulting material, possessing a high surface area of 251 m(2) g(-1) and a large carbon content of 52.1 wt %, can be directly used as the working electrode for oxygen evolution reaction without employing extra substrates or binders. This novel oxygen evolution electrode can smoothly operate in alkaline solutions (e.g., 0.1 and 1.0 M KOH), affording a low onset potential of 1.47 V (vs reversible hydrogen electrode) and a stable current density of 10.0 mA cm(-2) at 1.52 V in 0.1 M KOH solution for at least 30 h, associated with a high Faradaic efficiency of 99.3%. The achieved ultrahigh oxygen evolution activity and strong durability, with superior performance in comparison to the state-of-the-art noble-metal/transition-metal and nonmetal catalysts, originate from the unique nanowire array electrode configuration and in situ carbon incorporation, which lead to the large active surface area, enhanced mass/charge transport capability, easy release of oxygen gas bubbles, and strong structural stability. Furthermore, the hybrid Co3O4-carbon porous nanowire arrays can also efficiently catalyze oxygen reduction reaction, featuring a desirable four-electron pathway for reversible oxygen evolution and reduction, which is potentially useful for rechargeable metal-air batteries, regenerative fuel cells, and other important clean energy devices.

  5. Efficient array beam forming by spatial filtering for ultrasound B-mode imaging

    PubMed Central

    Kim, Kang-Sik; Liu, Jie; Insana, Michael F.

    2009-01-01

    This paper proposes an efficient array beam-forming method using spatial matched filtering (SMF) for ultrasonic imaging. In the proposed method, ultrasonic waves are transmitted from an array subaperture with fixed transmit focus as in conventional array imaging. At receive, radio frequency echo signals from each receive channel are passed through a spatial matched filter that is constructed based on the system transmit-receive spatial impulse response. The filtered echo signals are then summed without time delays. The filter concentrates and spatially registers the echo energy from each element so that the pulse-echo impulse response of the summed output is focused with acceptably low side lobes. Analytical beam pattern analysis and simulation results using a linear array show that this spatial filtering method can improve lateral resolution and contrast-to-noise ratio as compared with conventional dynamic receive focusing (DRF) methods. Experimental results with a linear array are consistent but point out the need to address additional practical issues. Spatial filtering is equivalent to synthetic aperture methods that dynamically focus on both transmit and receive throughout the field of view. In one common example of phase aberrations, the SMF method was degraded to a degree comparable to conventional DRF methods. PMID:16938973

  6. Hybrid Li-air battery cathodes with sparse carbon nanotube arrays directly grown on carbon fiber papers

    SciTech Connect

    Li, YF; Huang, ZP; Huang, K; Carnahan, D; Xing, YC

    2013-11-01

    Sparsely populated, vertically aligned nitrogen doped carbon nanotube arrays (CNTAs) with dislocated-graphene stacking were grown directly on carbon fiber papers and investigated as hierarchical air cathodes in hybrid Li-air batteries with aqueous catholytes. The CNTAs were made with electrodeposited Ni nanocatalysts, followed by plasma-enhanced chemical vapor deposition. The thus obtained CNTAs can reach a population number density as low as similar to 10(7) per cm(2) on the carbon fibers, achieving an extremely high porosity of over 99% for the active layer in the cathode. The sparse CNTAs not only provide effective pathways for the reacting species, but also show a significantly high catalytic activity, which is found to be comparable to that of a supported Pt electrocatalyst. The high activity of the CNTAs is attributed to the rich graphene edges exposed on the CNT surface and nitrogen doping. Hybrid Li-air batteries with such cathodes have shown a consistent discharging capacity of 710 mA h g(-1) and a specific energy of 2057 W h kg(-1) at 0.5 mA cm(-2). Stable charge-discharge cycling at 0.5 mA cm(-2) showed an average potential difference of 1.35 V, indicative of a relatively small overpotential and high round trip efficiency (71%). Furthermore, the hybrid Li-air battery based on the hierarchical cathode can reach a power density as high as 10.4 mW cm(-2).

  7. 1024 pixels single photon imaging array for 3D ranging

    NASA Astrophysics Data System (ADS)

    Bellisai, S.; Guerrieri, F.; Tisa, S.; Zappa, F.; Tosi, A.; Giudice, A.

    2011-01-01

    Three dimensions (3D) acquisition systems are driving applications in many research field. Nowadays 3D acquiring systems are used in a lot of applications, such as cinema industry or in automotive (for active security systems). Depending on the application, systems present different features, for example color sensitivity, bi-dimensional image resolution, distance measurement accuracy and acquisition frame rate. The system we developed acquires 3D movie using indirect Time of Flight (iTOF), starting from phase delay measurement of a sinusoidally modulated light. The system acquires live movie with a frame rate up to 50frame/s in a range distance between 10 cm up to 7.5 m.

  8. Hexabundles: imaging fiber arrays for low-light astronomical applications.

    PubMed

    Bland-Hawthorn, Joss; Bryant, Julia; Robertson, Gordon; Gillingham, Peter; O'Byrne, John; Cecil, Gerald; Haynes, Roger; Croom, Scott; Ellis, Simon; Maack, Martin; Skovgaard, Peter; Noordegraaf, Danny

    2011-01-31

    We demonstrate a novel imaging fiber bundle ("hexabundle") that is suitable for low-light applications in astronomy. The most successful survey instruments at optical-infrared wavelengths use hundreds to thousands of multimode fibers fed to one or more spectrographs. Since most celestial sources are spatially extended on the celestial sphere, a hexabundle provides spectroscopic information at many distinct locations across the source. We discuss two varieties of hexabundles: (i) lightly fused, closely packed, circular cores; (ii) heavily fused non-circular cores with higher fill fractions. In both cases, we find the important result that the cladding can be reduced to ~2 μm over the short fuse length, well below the conventional ~10λ thickness employed more generally, with a consequent gain in fill factor. Over the coming decade, it is to be expected that fiber-based instruments will be upgraded with hexabundles in order to increase the spatial multiplex capability by two or more orders of magnitude.

  9. Characterization of Genomic Alterations in Radiation-Associated Breast Cancer among Childhood Cancer Survivors, Using Comparative Genomic Hybridization (CGH) Arrays

    PubMed Central

    Yang, Xiaohong R.; Killian, J. Keith; Hammond, Sue; Burke, Laura S.; Bennett, Hunter; Wang, Yonghong; Davis, Sean R.; Strong, Louise C.; Neglia, Joseph; Stovall, Marilyn; Weathers, Rita E.; Robison, Leslie L.; Bhatia, Smita; Mabuchi, Kiyohiko; Inskip, Peter D.; Meltzer, Paul

    2015-01-01

    Ionizing radiation is an established risk factor for breast cancer. Epidemiologic studies of radiation-exposed cohorts have been primarily descriptive; molecular events responsible for the development of radiation-associated breast cancer have not been elucidated. In this study, we used array comparative genomic hybridization (array-CGH) to characterize genome-wide copy number changes in breast tumors collected in the Childhood Cancer Survivor Study (CCSS). Array-CGH data were obtained from 32 cases who developed a second primary breast cancer following chest irradiation at early ages for the treatment of their first cancers, mostly Hodgkin lymphoma. The majority of these cases developed breast cancer before age 45 (91%, n = 29), had invasive ductal tumors (81%, n = 26), estrogen receptor (ER)-positive staining (68%, n = 19 out of 28), and high proliferation as indicated by high Ki-67 staining (77%, n = 17 out of 22). Genomic regions with low-copy number gains and losses and high-level amplifications were similar to what has been reported in sporadic breast tumors, however, the frequency of amplifications of the 17q12 region containing human epidermal growth factor receptor 2 (HER2) was much higher among CCSS cases (38%, n = 12). Our findings suggest that second primary breast cancers in CCSS were enriched for an “amplifier” genomic subgroup with highly proliferative breast tumors. Future investigation in a larger irradiated cohort will be needed to confirm our findings. PMID:25764003

  10. Identification of DNA copy-number aberrations by array-comparative genomic hybridization in patients with schizophrenia.

    PubMed

    Moon, Ho Jin; Yim, Sung-Vin; Lee, Woon Kyu; Jeon, Yang-Whan; Kim, Young Hoon; Ko, Young Jin; Lee, Kwang-Soo; Lee, Kweon-Haeng; Han, Sang-Ick; Rha, Hyoung Kyun

    2006-06-02

    Chromosomal abnormalities are implicated as important markers for the pathogenesis in patients with schizophrenia. In this study, with using bacterial artificial chromosome (BAC) array-based comparative genomic hybridization (CGH), we analyzed DNA copy-number changes among 30 patients with schizophrenia. The most frequent changes were partial gain of Xq23 (52%) and loss of 3q13.12 (32%). Other frequent gains were found in: 1p, 6q, 10p, 11p, 11q, 14p, and 15q regions, and frequent losses were found in: 2p, 9q, 10q, 14q, 20q, and 22q regions. The set of abnormal regions was confirmed by real-time PCR (9q12, 9q34.2, 11p15.4, 14q32.33, 15q15.1, 22q11.21, and Xq23). All real-time PCR results were consistent with the array-CGH results. Therefore, it is suggested that array-CGH and real-time PCR analysis could be used as powerful tools in screening for schizophrenia-related genes. Our results might be useful for further exploration of candidate genomic regions in the pathogenesis of schizophrenia.

  11. A customized high-resolution array-comparative genomic hybridization to explore copy number variations in Parkinson's disease.

    PubMed

    La Cognata, Valentina; Morello, Giovanna; Gentile, Giulia; D'Agata, Velia; Criscuolo, Chiara; Cavalcanti, Francesca; Cavallaro, Sebastiano

    2016-10-01

    Parkinson's disease (PD), the second most common progressive neurodegenerative disorder, was long believed to be a non-genetic sporadic syndrome. Today, only a small percentage of PD cases with genetic inheritance patterns are known, often complicated by reduced penetrance and variable expressivity. The few well-characterized Mendelian genes, together with a number of risk factors, contribute to the major sporadic forms of the disease, thus delineating an intricate genetic profile at the basis of this debilitating and incurable condition. Along with single nucleotide changes, gene-dosage abnormalities and copy number variations (CNVs) have emerged as significant disease-causing mutations in PD. However, due to their size variability and to the quantitative nature of the assay, CNV genotyping is particularly challenging. For this reason, innovative high-throughput platforms and bioinformatics algorithms are increasingly replacing classical CNV detection methods. Here, we report the design strategy, development, validation and implementation of NeuroArray, a customized exon-centric high-resolution array-based comparative genomic hybridization (aCGH) tailored to detect single/multi-exon deletions and duplications in a large panel of PD-related genes. This targeted design allows for a focused evaluation of structural imbalances in clinically relevant PD genes, combining exon-level resolution with genome-wide coverage. The NeuroArray platform may offer new insights in elucidating inherited potential or de novo structural alterations in PD patients and investigating new candidate genes.

  12. Characterization of NIR InGaAs imager arrays for the JDEM SNAPmission concept

    SciTech Connect

    Seshadri, S.; Cole, M.D.; Hancock, B.; Ringold, P.; Wrigley, C.; Bonati, M.; Brown, M.G.; Schubnell, M.; Rahmer, G.; Guzman, D.; Figer,D.; Tarle, G.; Smith, R.M.; Bebek, C.

    2006-05-23

    We present the results of a study of the performance of InGaAs detectors conducted for the SuperNova Acceleration Probe (SNAP) dark energy mission concept. Low temperature data from a nominal 1.7um cut-off wavelength 1kx1k InGaAs photodiode array, hybridized to a Rockwell H1RG multiplexer suggest that InGaAs detector performance is comparable to those of existing 1.7um cut-off HgCdTe arrays. Advances in 1.7um HgCdTe dark current and noise initiated by the SNAP detector research and development program makes it the baseline detector technology for SNAP. However, the results presented herein suggest that existing InGaAs technology is a suitable alternative for other future astronomy applications.

  13. Optimization of acoustic emitted field of transducer array for ultrasound imaging.

    PubMed

    He, Zhengyao

    2014-01-01

    A method is proposed to calculate the weight vector of a transducer array for ultrasound imaging to obtain a low-sidelobe transmitting beam pattern based on the near-field response vector. An optimization problem is established, and the second-order cone (SOC) algorithm is used to solve the problem to obtain the weight vector. The optimized acoustic emitted field of the transducer array is then calculated using the Field II program by applying the obtained weight vector to the array. The simulation results with a 64-element 26 MHz linear phased array show that the proposed method can be used to control the sidelobe of the near-field transmitting beam pattern of the transducer array and achieve a low-sidelobe level. The near-field sound pressure distribution of the transducer array using the proposed method focuses much better than that using the standard delay and sum (DAS) beamforming method. The sound energy is more concentrated using the proposed method.

  14. Active millimeter-wave video rate imaging with a staring 120-element microbolometer array

    NASA Astrophysics Data System (ADS)

    Luukanen, Arttu; Miller, Aaron J.; Grossman, Erich N.

    2004-08-01

    Passive indoors imaging of weapons concealed under clothing poses a formidable challenge for millimeter-wave imagers due to the sub-picowatt signal levels present in the scene. Moreover, video-rate imaging requires a large number of pixels, which leads to a very complex and expensive front end for the imager. To meet the concealed weapons detection challenge, our approach uses a low cost pulsed-noise source as an illuminator and an array of room-temperature antenna-coupled microbolometers as the detectors. The reflected millimeter-wave power is detected by the bolometers, gated, integrated and amplified by audio-frequency amplifiers, and after digitization, displayed in real time on a PC display. We present recently acquired videos obtained with the 120-element array, and comprehensively describe the performance characteristics of the array in terms of sensitivity, optical efficiency, uniformity and spatial resolution. Our results show that active imaging with antenna-coupled microbolometers can yield imagery comparable to that obtained with systems using MMIC amplifiers but with a cost per pixel that is orders of magnitude lower.

  15. Implementation of a direct-imaging and FX correlator for the BEST-2 array

    NASA Astrophysics Data System (ADS)

    Foster, G.; Hickish, J.; Magro, A.; Price, D.; Zarb Adami, K.

    2014-04-01

    A new digital backend has been developed for the Basic Element for SKA Training II (BEST-2) array at Radiotelescopi di Medicina, INAF-IRA, Italy, which allows concurrent operation of an FX correlator, and a direct-imaging correlator and beamformer. This backend serves as a platform for testing some of the spatial Fourier transform concepts which have been proposed for use in computing correlations on regularly gridded arrays. While spatial Fourier transform-based beamformers have been implemented previously, this is, to our knowledge, the first time a direct-imaging correlator has been deployed on a radio astronomy array. Concurrent observations with the FX and direct-imaging correlator allow for direct comparison between the two architectures. Additionally, we show the potential of the direct-imaging correlator for time-domain astronomy, by passing a subset of beams though a pulsar and transient detection pipeline. These results provide a timely verification for spatial Fourier transform-based instruments that are currently in commissioning. These instruments aim to detect highly redshifted hydrogen from the epoch of reionization and/or to perform wide-field surveys for time-domain studies of the radio sky. We experimentally show the direct-imaging correlator architecture to be a viable solution for correlation and beamforming.

  16. Two-dimensional imaging via a narrowband MIMO radar system with two perpendicular linear arrays.

    PubMed

    Wang, Dang-wei; Ma, Xiao-yan; Su, Yi

    2010-05-01

    This paper presents a system model and method for the 2-D imaging application via a narrowband multiple-input multiple-output (MIMO) radar system with two perpendicular linear arrays. Furthermore, the imaging formulation for our method is developed through a Fourier integral processing, and the parameters of antenna array including the cross-range resolution, required size, and sampling interval are also examined. Different from the spatial sequential procedure sampling the scattered echoes during multiple snapshot illuminations in inverse synthetic aperture radar (ISAR) imaging, the proposed method utilizes a spatial parallel procedure to sample the scattered echoes during a single snapshot illumination. Consequently, the complex motion compensation in ISAR imaging can be avoided. Moreover, in our array configuration, multiple narrowband spectrum-shared waveforms coded with orthogonal polyphase sequences are employed. The mainlobes of the compressed echoes from the different filter band could be located in the same range bin, and thus, the range alignment in classical ISAR imaging is not necessary. Numerical simulations based on synthetic data are provided for testing our proposed method.

  17. Nonlinear ultrasonic phased array imaging of closed cracks using global preheating and local cooling

    NASA Astrophysics Data System (ADS)

    Ohara, Yoshikazu; Takahashi, Koji; Ino, Yoshihiro; Yamanaka, Kazushi

    2015-10-01

    Closed cracks are the main cause of underestimation in ultrasonic inspection, because the ultrasound transmits through the crack. Specifically, the measurement of closed-crack depth in coarse-grained materials, which are highly attenuative due to linear scatterings at the grains, is the most difficult issue. To solve this problem, we have developed a temporary crack opening method, global preheating and local cooling (GPLC), using tensile thermal stress, and a high-selectivity imaging method, load difference phased array (LDPA), based on the subtraction of phased array images between different stresses. To demonstrate our developed method, we formed a closed fatigue crack in coarse-grained stainless steel (SUS316L) specimen. As a result of applying it to the specimen, the high-selectivity imaging performance was successfully demonstrated. This will be useful in improving the measurement accuracy of closed-crack depths in coarse-grained material.

  18. Thermal imaging of plasma with a phased array antenna in QUEST

    SciTech Connect

    Mishra, Kishore Nagata, K.; Akimoto, R.; Banerjee, S.; Idei, H.; Zushi, H.; Hanada, K.; Hasegawa, M.; Nakamura, K.; Fujisawa, A.; Nagashima, Y.; Onchi, T.; Kuzmin, A.; Yamamoto, M. K.

    2014-11-15

    A thermal imaging system to measure plasma Electron Bernstein Emission (EBE) emanating from the mode conversion region in overdense plasma is discussed. Unlike conventional ECE/EBE imaging, this diagnostics does not employ any active mechanical scanning mirrors or focusing optics to scan for the emission cones in plasma. Instead, a standard 3 × 3 waveguide array antenna is used as a passive receiver to collect emission from plasma and imaging reconstruction is done by accurate measurements of phase and intensity of these signals by heterodyne detection technique. A broadband noise source simulating the EBE, is installed near the expected mode conversion region and its position is successfully reconstructed using phase array technique which is done in post processing.

  19. Optimal reconfiguration maneuvers for spacecraft imaging arrays in multi-body regimes

    NASA Astrophysics Data System (ADS)

    Millard, Lindsay D.; Howell, Kathleen C.

    2008-12-01

    Upcoming National Aeronautics and Space Administration (NASA) mission concepts include satellite arrays to facilitate imaging and identification of distant planets. These mission scenarios are diverse, including designs such as the terrestrial planet finder-occulter (TPF-O), where a monolithic telescope is aided by a single occulter spacecraft, and the micro-arcsecond X-ray imaging mission (MAXIM), where as many as 16 spacecraft move together to form a space interferometer. Each design, however, requires precise reconfiguration and star tracking in potentially complex dynamic regimes. This paper explores control methods for satellite imaging array reconfiguration in multi-body systems. Specifically, optimal nonlinear control and geometric control methods are derived and compared to the more traditional linear quadratic regulators, as well as input state feedback linearization. These control strategies are implemented and evaluated for the TPF-O mission concept.

  20. Sensitivity- and effort-gain analysis: multilead ECG electrode array selection for activation time imaging.

    PubMed

    Hintermüller, Christoph; Seger, Michael; Pfeifer, Bernhard; Fischer, Gerald; Modre, Robert; Tilg, Bernhard

    2006-10-01

    Methods for noninvasive imaging of electric function of the heart might become clinical standard procedure the next years. Thus, the overall procedure has to meet clinical requirements as an easy and fast application. In this paper, we propose a new electrode array which improves the resolution of methods for activation time imaging considering clinical constraints such as easy to apply and compatibility with routine leads. For identifying the body-surface regions where the body surface potential (BSP) is most sensitive to changes in transmembrane potential (TMP), a virtual array method was used to compute local linear dependency (LLD) maps. The virtual array method computes a measure for the LLD in every point on the body surface. The most suitable number and position of the electrodes within the sensitive body surface regions was selected by constructing effort gain (EG) plots. Such a plot depicts the relative attainable rank of the leadfield matrix in relation to the increase in number of electrodes required to build the electrode array. The attainable rank itself was computed by a detector criterion. Such a criterion estimates the maximum number of source space eigenvectors not covered by noise when being mapped to the electrode space by the leadfield matrix and recorded by a detector. From the sensitivity maps, we found that the BSP is most sensitive to changes in TMP on the upper left frontal and dorsal body surface. These sensitive regions are covered best by an electrode array consisting of two L-shaped parts of approximately 30 cm x 30 cm and approximately 20 cm x 20 cm. The EG analysis revealed that the array meeting clinical requirements best and improving the resolution of activation time imaging consists of 125 electrodes with a regular horizontal and vertical spacing of 2-3 cm.

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