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Sample records for imaging arrays hybridized

  1. Hybrid monopole/loop coil array for human head MR imaging at 7T

    PubMed Central

    Yan, Xinqiang; Wei, Long; Xue, Rong; Zhang, Xiaoliang

    2015-01-01

    The monopole coil and loop coil have orthogonal radiofrequency (RF) fields and thus are intrinsically decoupled electromagnetically if they are laid out appropriately. In this study, we proposed a hybrid monopole/loop technique which could combine the advantages of both loop arrays and monopole arrays. To investigate this technique, a hybrid RF coil array containing 4 monopole channels and 4 loop channels was developed for human head MR imaging at 7T. In vivo MR imaging and g-factor results using monopole-only channels, loop-only channels and all channels of the hybrid array were acquired and evaluated. Compared with the monopole-only and loop-only channels, the proposed hybrid array has higher SNR and better parallel imaging performance. Sufficient electromagnetic decoupling and diverse RF magnetic field (B1) distributions of monopole channels and loop channels may contribute to this performance improvement. From experimental results, the hybrid monopole/loop array has low g-factor and excellent SNR at both periphery and center of the brain, which is valuable for human head imaging at ultrahigh fields. PMID:26120252

  2. High-resolution seismic array imaging based on an SEM-FK hybrid method

    NASA Astrophysics Data System (ADS)

    Tong, Ping; Chen, Chin-wu; Komatitsch, Dimitri; Basini, Piero; Liu, Qinya

    2014-04-01

    We demonstrate the feasibility of high-resolution seismic array imaging based on teleseismic recordings using full numerical wave simulations. We develop a hybrid method that interfaces a frequency-wavenumber (FK) calculation, which provides analytical solutions to 1-D layered background models with a spectral-element (SEM) numerical solver to calculate synthetic responses of local media to plane-wave incidence.This hybrid method accurately deals with local heterogeneities and discontinuity undulations, and represents an efficient tool for the forward modelling of teleseismic coda (including converted and scattered) waves. We benchmark the accuracy of the SEM-FK hybrid method against FK solutions for 1-D media. We then compute sensitivity kernels for teleseismic coda waves by interacting the forward teleseismic waves with an adjoint wavefield, produced by injecting coda waves as adjoint sources, based on adjoint techniques. These sensitivity kernels provide the basis for mapping variations in subsurface discontinuities, density and velocity structures through non-linear conjugate-gradient methods. We illustrate various synthetic imaging experiments, including discontinuity characterization, volumetric structural inversion for the crust or subduction zones. These tests show that using pre-conditioners based upon the scaled product of sensitivity kernels for different phases, combining finite-frequency traveltime and waveform inversion, and/or adopting hierarchical inversions from long- to short-period waveforms could reduce the non-linearity of the seismic inverse problem and speed up its convergence. The encouraging results of these synthetic examples suggest that inversion of teleseismic coda phases based on the SEM-FK hybrid method and adjoint techniques is a promising tool for structural imaging beneath dense seismic arrays.

  3. A 3-D spectral-element and frequency-wave number hybrid method for high-resolution seismic array imaging

    NASA Astrophysics Data System (ADS)

    Tong, Ping; Komatitsch, Dimitri; Tseng, Tai-Lin; Hung, Shu-Huei; Chen, Chin-Wu; Basini, Piero; Liu, Qinya

    2014-10-01

    We present a three-dimensional (3-D) hybrid method that interfaces the spectral-element method (SEM) with the frequency-wave number (FK) technique to model the propagation of teleseismic plane waves beneath seismic arrays. The accuracy of the resulting 3-D SEM-FK hybrid method is benchmarked against semianalytical FK solutions for 1-D models. The accuracy of 2.5-D modeling based on 2-D SEM-FK hybrid method is also investigated through comparisons to this 3-D hybrid method. Synthetic examples for structural models of the Alaska subduction zone and the central Tibet crust show that this method is capable of accurately capturing interactions between incident plane waves and local heterogeneities. This hybrid method presents an essential tool for the receiver function and scattering imaging community to verify and further improve their techniques. These numerical examples also show the promising future of the 3-D SEM-FK hybrid method in high-resolution regional seismic imaging based on waveform inversions of converted/scattered waves recorded by seismic array.

  4. Investigation of hybrid pixel detector arrays by synchrotron-radiation imaging

    NASA Astrophysics Data System (ADS)

    Helfen, L.; Myagotin, A.; Pernot, P.; DiMichiel, M.; Mikulík, P.; Berthold, A.; Baumbach, T.

    2006-07-01

    Synchrotron-radiation imaging was applied to the non-destructive testing of detector devices during their development cycle. Transmission imaging known as computed laminography was used to examine the microstructure of the interconnections in order to investigate the perfection of technological steps necessary for hybrid detector production. A characterisation of the solder bump microstructure can reveal production flaws such as missing or misaligned bumps, voids in bumps or bridges and thus give valuable information about the bonding process.

  5. 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. PMID:21041399

  6. 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. PMID:20707441

  7. Case for a field-programmable gate array multicore hybrid machine for an image-processing application

    NASA Astrophysics Data System (ADS)

    Rakvic, Ryan N.; Ives, Robert W.; Lira, Javier; Molina, Carlos

    2011-01-01

    General purpose computer designers have recently begun adding cores to their processors in order to increase performance. For example, Intel has adopted a homogeneous quad-core processor as a base for general purpose computing. PlayStation3 (PS3) game consoles contain a multicore heterogeneous processor known as the Cell, which is designed to perform complex image processing algorithms at a high level. Can modern image-processing algorithms utilize these additional cores? On the other hand, modern advancements in configurable hardware, most notably field-programmable gate arrays (FPGAs) have created an interesting question for general purpose computer designers. Is there a reason to combine FPGAs with multicore processors to create an FPGA multicore hybrid general purpose computer? Iris matching, a repeatedly executed portion of a modern iris-recognition algorithm, is parallelized on an Intel-based homogeneous multicore Xeon system, a heterogeneous multicore Cell system, and an FPGA multicore hybrid system. Surprisingly, the cheaper PS3 slightly outperforms the Intel-based multicore on a core-for-core basis. However, both multicore systems are beaten by the FPGA multicore hybrid system by >50%.

  8. 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

  9. Short wavelength infrared hybrid focal plane arrays

    NASA Technical Reports Server (NTRS)

    Vural, K.; Blackwell, J. D.; Marin, E. C.; Edwall, D. D.; Rode, J. P.

    1983-01-01

    The employment of area focal plane arrays (FPA) has made it possible to obtain second generation infrared imaging systems with high resolution and sensitivity. The Short Wavelength Infrared (SWIR) region (1-2.5 microns) is of importance for imaging objects at high temperature and under conditions of reflected sunlight. The present investigation is concerned with electrooptical characterization results for 32 x 32 SWIR detector arrays and FPAs which are suitable for use in a prototype imaging spectrometer. The employed detector material is Hg(1-x)Cd(x)Te grown by liquid phase epitaxy on a CdTe transparent substrate. Attention is given to details of processing, the design of the detector array, the multiplexer, the fabrication of the hybrid FPA, and aspects of performance.

  10. Real-time detection of DNA hybridization on microarray using a CCD-based imaging system equipped with a rotated microlens array disk.

    PubMed

    Mogi, Takeyuki; Hatakeyama, Keiichi; Taguchi, Tomoyuki; Wake, Hitoshi; Tanaami, Takeo; Hosokawa, Masahito; Tanaka, Tsuyoshi; Matsunaga, Tadashi

    2011-01-15

    This work describes a novel charge-coupled device (CCD)-based imaging system (MB Biochip Reader™) for real-time detection of DNA hybridization to DNA microarrays. The MB Biochip Reader™ consisted of a laser light source (532 nm), a microlens array for generation of a multi-beam laser, and a CCD for 2-D signal imaging. The MB Biochip Reader™ with a rotated microlens array, allowed large-field imaging (6.2 mm × 7.6 mm with 6.45 μm resolution) with fast time-resolution at 0.2 s without speckle noise. Furthermore, real-time detection of DNA hybridization, which is sufficient to obtain accurate data from tens of thousands of array element per field, was successfully performed without the need for laser scanning. The performance of the MB Biochip Reader™ for DNA microarray imaging was similar to the commercially available photomultiplier tube (PMT)-based microarray scanner, ScanArray Lite. The system potentially could be applied toward real-time analysis in many other fluorescent techniques in addition to real-time DNA microarray analysis. PMID:20951567

  11. 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

  12. 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.

  13. 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.

  14. 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.

  15. Short Wavelength Infrared Hybrid Focal Plane Arrays

    NASA Astrophysics Data System (ADS)

    Vural, K.; Blackwell, J. D...; Marin, E. C.; Edwall, D. D...; Rode, J. P.

    1983-11-01

    Short wavelength (λc = 2.5 μm) 32 x 32 HgCdTe focal plane arrays have been fabricated for use in an Airborne Imaging Spectrometer (AIS) developed by the Jet Propulsion Labora-tory for NASA. An Imaging Spectrometer provides simultaneous imaging of several spectral bands for applications in the sensing and monitoring of earth resources. The detector material is HgCdTe grown on CdTe substrates using liquid phase epitaxy. Planar processing is used to make photovoltaic detectors on 68 um centers. The detector array is mated to a silicon charge coupled device multiplexer to make hybrid focal plane arrays. Results show high performance detectors with a mean RoA = 9.6 x 107 Ω --cm2 and IleakAge (-100 mV) = 0.037 pA at 120K and near zero background. The yield and uniformity are high. The ratio of the standard deviation of the dc responsivity to the mean is 3% for 98.5% of the pixels. The D1.0 = 1.3 x 1012 cm - âœ"fiz/W at a background of 1013 ph/cm2-s and 120K which is close to the background limited (BLIP) D* of 1.9 x 1012 cm- âœ"Hz/W.

  16. Performance measurements of hybrid PIN diode arrays

    SciTech Connect

    Shapiro, S.L. ); Arens, J.F.; Jernigan, J.G. . Space Sciences Lab.); Kramer, G. ); Collins, T.; Worley, S. ); Wilburn, C.D. ); Skubic, P. )

    1990-10-01

    We report the successful development of hybrid PIN diode arrays and a series of room-temperature measurements in a high-energy pion beam at FNAL. A PMOS VLSI 256 {times} 256 readout array having 30 {mu}m square pixels was indium-bump bonded to a mating PIN diode detector array. Preliminary measurements on the resulting hybrid show excellent signal-to-noise at room temperature. 3 refs., 5 figs.

  17. Hybrid image processing

    NASA Technical Reports Server (NTRS)

    Juday, Richard D.

    1990-01-01

    Partly-digital, partly-optical 'hybrid' image processing attempts to use the properties of each domain to synergistic advantage: while Fourier optics furnishes speed, digital processing allows the use of much greater algorithmic complexity. The video-rate image-coordinate transformation used is a critical technology for real-time hybrid image-pattern recognition. Attention is given to the separation of pose variables, image registration, and both single- and multiple-frame registration.

  18. Hybrid Infrared Imager

    NASA Technical Reports Server (NTRS)

    Bailey, Gary C.

    1989-01-01

    Experimental device has low noise and high uniformity. Infrared imaging device combines array of InSb photodetectors with array of silicon field-effect-transistor switches. InSb chip forms roof over Si chip, each InSb detector cell engaging indium bump on corresponding Si switch cell below it. FET switches in 128-by-128 array turn on in sequence, read out charges on 128-by-128 array of photodetectors and multiplex them in serial output that represents pattern of light on array of photodetectors. Useful in sensitive infrared cameras for astronomy, medicine, inspection, and military surveillance. Reads out image data at rates up to 10 MHz and expands to 256-by-256 array.

  19. 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.

  20. 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

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

    PubMed

    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. PMID:23979460

  2. 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. PMID:21041400

  3. Hybrid Beamforming and Steering With Reconfigurable Arrays

    PubMed Central

    Hooi, Fong Ming; Thomenius, Kai E.; Fisher, Rayette; Carson, Paul L.

    2010-01-01

    Reconfigurable arrays offer an advantage over traditional ultrasound arrays because of their flexibility in channel selection. To improve ultrasound beamforming and coverage through beam steering, we propose a hybrid beamforming technique to elongate the depth of focus of transmit beams and a method of element selection that improves steering capabilities that take advantage of array reconfigurability using annular rings. A local minimization technique to optimize the hybrid aperture is discussed in this paper. The chosen hybrid apertures covering four focal zones result in improved range in depth of focus when compared with pure spherical beams via point spread functions (PSF) and lesion signal-tonoise ratio (LSNR) calculations. Improvements were statistically significant at focal depth extremes. Our method of beam steering utilizing a quantized phase delay selection to minimize delay errors indicated better performance by removing an artifact present with traditional ringed element selection. PMID:20529707

  4. 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. PMID:26320423

  5. 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.

  6. Performance measurements of hybrid PIN diode arrays

    SciTech Connect

    Jernigan, J.G.; Arens, J.F. . Space Sciences Lab.); Kramer, G. ); Collins, T.; Herring, J. ); Shapiro, S.L. ); Wilburn, C.D. )

    1990-05-01

    We report on the successful effort to develop hybrid PIN diode arrays and to demonstrate their potential as components of vertex detectors. Hybrid pixel arrays have been fabricated by the Hughes Aircraft Co. by bump bonding readout chips developed by Hughes to an array of PIN diodes manufactured by Micron Semiconductor Inc. These hybrid pixel arrays were constructed in two configurations. One array format having 10 {times} 64 pixels, each 120 {mu}m square, and the other format having 256 {times} 256 pixels, each 30 {mu}m square. In both cases, the thickness of the PIN diode layer is 300 {mu}m. Measurements of detector performance show that excellent position resolution can be achieved by interpolation. By determining the centroid of the charge cloud which spreads charge into a number of neighboring pixels, a spatial resolution of a few microns has been attained. The noise has been measured to be about 300 electrons (rms) at room temperature, as expected from KTC and dark current considerations, yielding a signal-to-noise ratio of about 100 for minimum ionizing particles. 4 refs., 13 figs.

  7. Global trends in hybrid imaging.

    PubMed

    Hricak, Hedvig; Choi, Byung Ihn; Scott, Andrew M; Sugimura, Kazuro; Muellner, Ada; von Schulthess, Gustav K; Reiser, Maximilian F; Graham, Michael M; Dunnick, N Reed; Larson, Steven M

    2010-11-01

    At the 2009 Scientific Assembly and Annual Meeting of the Radiological Society of North America, a special session was devoted to global trends in hybrid imaging. This article expands on the key points of the session, focusing primarily on positron emission tomography/computed tomography. Global trends in hybrid imaging equipment acquisition, usage, and image interpretation practices are reviewed, and emerging requirements for training and clinical privileging are discussed. Also considered are the current benefits of hybrid imaging for patient care and workflow and the potential of hybrid imaging for advancing drug development and personalized medicine. PMID:20829539

  8. Hybrid optoacoustic tomography and pulse-echo ultrasonography using concave arrays.

    PubMed

    Merčep, Elena; Jeng, Gency; Morscher, Stefan; Li, Pai-Chi; Razansky, Daniel

    2015-09-01

    Implementation of hybrid imaging using optoacoustic tomography (OAT) and ultrasound (US) brings together the important advantages and complementary features of both methods. However, the fundamentally different physical contrast mechanisms of the two modalities may impose significant difficulties in the optimal tomographic data acquisition and image formation strategies. We investigate the applicability of the commonly applied imaging geometries for acquisition and reconstruction of hybrid optoacoustic tomography and pulse-echo ultrasound (OPUS) images. Optimization of the ultrasound image formation strategy using concave array geometry was implemented using a synthetic aperture method combined with spatial compounding. Experimental validation was performed using a custom-made multiplexer unit executing switching between the two modalities employing the same transducer array. A variety of array probes with different angular coverages were subsequently tested, including arrays for clinical hand-held imaging as well as stationary arrays for tomographic small animal imaging. The results demonstrate that acquisition of OAT data by mere addition of an illumination source to the common US linear array geometry may result in significant limited-view artifacts and overall loss of image quality. On the other hand, unsatisfactory US image quality is achieved with tomographic arrays solely optimized for OAT image acquisition without considering the optimal transmit-receive beamforming parameters. Optimal selection of the array pitch size, tomographic coverage and spatial compounding parameters has achieved here an accurate hybrid imaging performance, which was experimentally showcased in tissuemimicking phantoms, post-mortem mice, and hand-held imaging of a healthy volunteer. The efficient combination of the two modalities in a single imaging device reveals the true power of functional and molecular imaging capacities of OAT in addition to the morphological and functional

  9. High-resolution seismic array imaging using teleseismic scattered waves

    NASA Astrophysics Data System (ADS)

    Tong, P.; Liu, Q.; Chen, C.; Basini, P.; Komatitsch, D.

    2013-12-01

    The advent of dense seismic networks, new modeling and imaging techniques, and increased HPC capacity makes it feasible to resolve subsurface interfaces and structural anomalies beneath seismic arrays at unprecedented details based on teleseismic scattered records. To accurately and efficiently simulate the full propagation of teleseismic waves beneath receiver arrays at the frequencies relevant to scattering imaging, we develop a hybrid method that interfaces a frequency-wavenumber (FK) calculation, which provides semi-analytical solutions to one-dimensional layered background models, with a 2D/3D spectral-element (SEM) numerical solver to calculate synthetic responses of local media to plane-wave incidence. This hybrid method accurately deals with local heterogeneities and discontinuity undulations, and represents an efficient tool for the forward modelling of teleseismic coda (including converted and scattered) waves. Meanwhile, adjoint tomography is a powerful tool for high-resolution imaging in heterogeneous media, which can resolve large velocity contrasts through the use of 2D/3D initial models and full numerical simulations for forward wavefields and sensitivity kernels. In the framework of adjont tomography and hybrid method, we compute sensitivity kernels for teleseismic coda waves, which provide the basis for mapping variations in subsurface discontinuities, density and velocity structures through nonlinear conjugate-gradient methods. Various 2D synthetic imaging examples show that inversion of teleseismic coda phases based on the 2D SEM-FK hybrid method and adjoint techniques is a promising tool for structural imaging beneath dense seismic arrays. 3D synthetic experiments will be performed to test the feasibility of seismic array imaging using adjoint method and 3D SEM-FK hybrid method. We will also apply this hybrid imaging techniques to realistic seismic data, such as the recorded SsPmP phases in central Tibet, to explore high-resolution subsurface

  10. 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.

  11. Array technology for terahertz imaging

    NASA Astrophysics Data System (ADS)

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

    2012-06-01

    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.

  12. 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.

  13. 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.

  14. Hybrid fusion and demosaicing algorithm with near-infrared image

    NASA Astrophysics Data System (ADS)

    Luo, X. Y.; Zhang, J.; Dai, Q. H.

    2014-05-01

    In this paper, we propose a unified framework for color filter array (CFA) interpolation and visible/NIR image combination. The proposed method aims to reconstruct a high quality image from raw CFA data and the corresponding NIR image, similar to a multi-spectral fusion of color and NIR images. Based on NIR image, we impose a sparse constraint of gradient difference to modify the traditional color interpolation. The experiments indicate the effectiveness of our hybrid scheme to acquire joint color and NIR information in real-time, and show that this hybrid process can generate a better color image when compared with treating interpolation and fusion separately.

  15. 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.

  16. 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.

  17. Direct fluorescence analysis of genetic polymorphisms by hybridization with oligonucleotide arrays on glass supports.

    PubMed Central

    Guo, Z; Guilfoyle, R A; Thiel, A J; Wang, R; Smith, L M

    1994-01-01

    A simple and rapid method for the analysis of genetic polymorphisms has been developed using allele-specific oligonucleotide arrays bound to glass supports. Allele-specific oligonucleotides are covalently immobilized on glass slides in arrays of 3 mm spots. Genomic DNA is amplified by PCR using one fluorescently tagged primer oligonucleotide and one biotinylated primer oligonucleotide. The two complementary DNA strands are separated, the fluorescently tagged strand is hybridized to the support-bound oligonucleotide array, and the hybridization pattern is detected by fluorescence scanning. Multiple polymorphisms present in the PCR product may be detected in parallel. The effect of spacer length, surface density and hybridization conditions were evaluated, as was the relative efficacy of hybridization with single or double-stranded PCR products. The utility of the method was demonstrated in the parallel analysis of 5 point mutations from exon 4 of the human tyrosinase gene. Images PMID:7816638

  18. Current-mode CMOS hybrid image sensor

    NASA Astrophysics Data System (ADS)

    Benyhesan, Mohammad Kassim

    Digital imaging is growing rapidly making Complimentary Metal-Oxide-Semi conductor (CMOS) image sensor-based cameras indispensable in many modern life devices like cell phones, surveillance devices, personal computers, and tablets. For various purposes wireless portable image systems are widely deployed in many indoor and outdoor places such as hospitals, urban areas, streets, highways, forests, mountains, and towers. However, the increased demand on high-resolution image sensors and improved processing features is expected to increase the power consumption of the CMOS sensor-based camera systems. Increased power consumption translates into a reduced battery life-time. The increased power consumption might not be a problem if there is access to a nearby charging station. On the other hand, the problem arises if the image sensor is located in widely spread areas, unfavorable to human intervention, and difficult to reach. Given the limitation of energy sources available for wireless CMOS image sensor, an energy harvesting technique presents a viable solution to extend the sensor life-time. Energy can be harvested from the sun light or the artificial light surrounding the sensor itself. In this thesis, we propose a current-mode CMOS hybrid image sensor capable of energy harvesting and image capture. The proposed sensor is based on a hybrid pixel that can be programmed to perform the task of an image sensor and the task of a solar cell to harvest energy. The basic idea is to design a pixel that can be configured to exploit its internal photodiode to perform two functions: image sensing and energy harvesting. As a proof of concept a 40 x 40 array of hybrid pixels has been designed and fabricated in a standard 0.5 microm CMOS process. Measurement results show that up to 39 microW of power can be harvested from the array under 130 Klux condition with an energy efficiency of 220 nJ /pixel /frame. The proposed image sensor is a current-mode image sensor which has several

  19. a 40 GHZ Planar Array Antenna Using Hybrid Coupling

    NASA Astrophysics Data System (ADS)

    van der Wilt, F. P.; Strijbos, J. H. M.

    A new linearly polarized microstrip patch array is presented. The array is fed by using a combination of aperture coupling from a slotted waveguide and coplanar feeding using series-fed patch arrays. Advantages of this so-called hybrid coupling are easy control of the illumination of the array and a low feed loss, since the number of microstrip lines is kept to the minimum. In the paper we discuss how to design a Hybrid Coupled Planar Array (HCPA) antenna by using CAD modeling. Furthermore, we discuss several more features of the antenna type, such as its reasonable bandwidth, low cross-polarization and constructional simplicity. A 40 GHz 120-element HCPA antenna with a broadside beam has been built and tested. Experimental results for this array are presented.

  20. Utility of array comparative genomic hybridization in cytogenetic analysis.

    PubMed

    Singh, Rashmi R; Cheung, K-John J; Horsman, Douglas E

    2011-01-01

    Conventional comparative genomic hybridization (CGH), high-resolution oligonucleotide, and BAC array CGH have modernized the field of cytogenetics to enable access to unbalanced genomic aberrations such as whole or partial chromosomal gains and losses. The basic principle of array CGH involves hybridizing differentially labeled proband/test (e.g., tumor) and normal reference DNA on an array of oligonucleotide or BAC clones instead of normal metaphases as in conventional CGH. The sub-megabase resolution tiling BAC arrays are extremely useful for the analysis of acquired aberrations in cancer genomes. Array CGH can be extremely useful to identify the chromosomal makeup of marker and ring chromosomes, to define/delineate the precise location/bands involved in structural aberrations and the accurate localization of translocation breakpoints in both simple and complex karyotypes either alone or in combination with standard karyotype analysis. PMID:21431645

  1. 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.

  2. Hybridization process for back-illuminated silicon Geiger-mode avalanche photodiode arrays

    NASA Astrophysics Data System (ADS)

    Schuette, Daniel R.; Westhoff, Richard C.; Loomis, Andrew H.; Young, Douglas J.; Ciampi, Joseph S.; Aull, Brian F.; Reich, Robert K.

    2010-04-01

    We present a unique hybridization process that permits high-performance back-illuminated silicon Geiger-mode avalanche photodiodes (GM-APDs) to be bonded to custom CMOS readout integrated circuits (ROICs) - a hybridization approach that enables independent optimization of the GM-APD arrays and the ROICs. The process includes oxide bonding of silicon GM-APD arrays to a transparent support substrate followed by indium bump bonding of this layer to a signal-processing ROIC. This hybrid detector approach can be used to fabricate imagers with high-fill-factor pixels and enhanced quantum efficiency in the near infrared as well as large-pixel-count, small-pixel-pitch arrays with pixel-level signal processing. In addition, the oxide bonding is compatible with high-temperature processing steps that can be used to lower dark current and improve optical response in the ultraviolet.

  3. Coulomb blockage of hybridization in two-dimensional DNA arrays

    NASA Astrophysics Data System (ADS)

    Vainrub, Arnold; Pettitt, B. Montgomery

    2002-10-01

    Experiments on DNA microarrays have revealed substantial differences in hybridization thermodynamics between DNA free in solution and surface tethered DNA. Here we develop a mean field model of the Coulomb effects in two-dimensional DNA arrays to understand the binding isotherms and thermal denaturation of the double helix. We find that the electrostatic repulsion of the assayed nucleic acid from the array of DNA probes dominates the binding thermodynamics, and thus causes the Coulomb blockage of the hybridization. The results explain, observed in DNA microarrays, the dramatic decrease of the hybridization efficiency and the thermal denaturation curve broadening as the probe surface density grows. We demonstrate application of the theory for evaluation and optimization of the sensitivity, specificity, and the dynamic range of DNA array devices.

  4. 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.

  5. 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.

  6. Microelectrode arrays fabricated using a novel hybrid microfabrication method.

    PubMed

    Merlo, Mark W; Snyder, Russell L; Middlebrooks, John C; Bachman, Mark

    2012-02-01

    We present novel hybrid microfabrication methods for microelectrode arrays that combine microwire assembly, microelectromechanical systems (MEMS) manufacturing techniques and precision tool-based micromachining. This combination enables hybrid microfabrication to produce complex geometries and structures, increase material selection, and improve integration. A 32-channel shank microelectrode array was fabricated to highlight the hybrid microfabrication techniques. The electrode shank was 130 μm at its narrowest, had a 127 μm thickness and had iridium oxide electrode sites that were 25 μm in diameter with 150 μm spacing. Techniques used to fabricate this electrode include microassembly of insulated gold wires into a micromold, micromolding the microelectrode shank, post molding machining, sacrificial release of the microelectrode and electrodeposition of iridium oxide onto the microelectrode sites. Electrode site position accuracy was shown to have a standard deviation of less than 4 μm. Acute in vivo recordings with the 32-channel shank microelectrode array demonstrated comparable performance to that obtained with commercial microelectrode arrays. This new approach to microelectrode array fabrication will enable new microelectrodes, such as multi-sided arrays, drug eluding electrodes and biodegradable shanks. PMID:21979567

  7. Microelectrode arrays fabricated using a novel hybrid microfabrication method

    PubMed Central

    Merlo, Mark W.; Snyder, Russell L.; Middlebrooks, John C.; Bachman, Mark

    2011-01-01

    We present novel hybrid microfabrication methods for microelectrode arrays that combine microwire assembly, microelectromechanical systems (MEMS) manufacturing techniques and precision tool-based micromachining. This combination enables hybrid microfabrication to produce complex geometries and structures, increase material selection, and improve integration. A 32-channel shank microelectrode array was fabricated to highlight the hybrid microfabrication techniques. The electrode shank was 130 μm at its narrowest, had a 127 μm thickness and had iridium oxide electrode sites that were 25 μm in diameter with 150 μm spacing. Techniques used to fabricate this electrode include microassembly of insulated gold wires into a micromold, micromolding the microelectrode shank, post molding machining, sacrificial release of the microelectrode and electrodeposition of iridium oxide onto the microelectrode sites. Electrode site position accuracy was shown to have a standard deviation of less than 4 μm. Acute in vivo recordings with the 32-channel shank microelectrode array demonstrated comparable performance to that obtained with commercial microelectrode arrays . This new approach to microelectrode array fabrication will enable new microelectrodes, such as multi-sided arrays, drug eluding electrodes and biodegradable shanks. PMID:21979567

  8. Tomographical imaging using uniformly redundant arrays

    NASA Technical Reports Server (NTRS)

    Cannon, T. M.; Fenimore, E. E.

    1979-01-01

    An investigation is conducted of the behavior of two types of uniformly redundant array (URA) when used for close-up imaging. One URA pattern is a quadratic residue array whose characteristics for imaging planar sources have been simulated by Fenimore and Cannon (1978), while the second is based on m sequences that have been simulated by Gunson and Polychronopulos (1976) and by MacWilliams and Sloan (1976). Close-up imaging is necessary in order to obtain depth information for tomographical purposes. The properties of the two URA patterns are compared with a random array of equal open area. The goal considered in the investigation is to determine if a URA pattern exists which has the desirable defocus properties of the random array while maintaining artifact-free image properties for in-focus objects.

  9. 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.

  10. Astronomical imaging with InSb arrays

    NASA Astrophysics Data System (ADS)

    Pipher, Judith L.

    Ten years ago, Forrest presented the first astronomical images with a Santa Barbara Research Center (SBRC) 32 x 32 InSb array camera at the first NASA-Ames Infrared Detector Technology Work-shop. Soon after, SBRC began development of 58 x 62 InSb arrays, both for ground-based astronomy and for the Space Infrared Telescope Facility (SIRTF). By the time of the 1987 Hilo workshop 'Ground-based Astronomical Observations with Infrared Array Dectectors' astronomical results from cameras based on SBRC 32 x 32 and 58 x 62 InSb arrays, a CE linear InSb array, and a French 32 x 32 InSb charge injection device (CID) array were presented. And at the Tucson 1990 meeting 'Astrophysics with Infrared Arrays', it was clear that this new technology was no longer the province of 'IR pundits', but provided a tool for all astronomers. At this meeting, the first astronomical observations with SBRC's new, gateless passivation 256 x 256 InSb arrays will be presented: they perform spectacularly] In this review, I can only broadly brush on the interesting science completed with InSb array cameras. Because of the broad wavelength coverage (1-5.5 micrometer) of InSb, and the extremely high performance levels throughout the band, InSb cameras are used not only in the near IR, but also from 3-5.5 micrometer, where unique science is achieved. For example, the point-like central engines of active galactic nuclei (AGN) are delineated at L' and M', and Bra and 3.29 micrometer dust emission images of galactic and extragalactic objects yield excitation conditions. Examples of imaging spectroscopy, high spatial resolution imaging, as well as deep, broad-band imaging with InSb cameras at this meeting illustrate the power of InSb array cameras.

  11. 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.

  12. 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.

  13. Silicon PIN diode array hybrids for charged particle detection

    SciTech Connect

    Shapiro, S.L.; Dunwoodie, W.M.; Arens, J.F.; Jernigan, J.G.; Gaalema, S.

    1988-09-01

    We report on the design of silicon PIN diode array hybrids for use as charged particle detectors. A brief summary of the need for vertex detectors is presented. Circuitry, block diagrams and device specifications are included. 8 refs., 7 figs., 1 tab.

  14. 256 x 256 hybrid HgCdTe infrared focal plane arrays

    NASA Astrophysics Data System (ADS)

    Bailey, Robert B.; Kozlowski, Lester J.; Chen, Jenkon; Bui, Duc Q.; Vural, Kadri

    1991-05-01

    Hybrid HgCdTe 256 x 256 focal plane arrays have been developed to meet the sensitivity, resolution, and field-of-view requirements of high-performance medium-wavelength infrared (MWIR) imaging systems. The detector arrays for these hybrids are fabricated on substrates that reduce or eliminate the thermal expansion mismatch to the silicon readout circuit. The readouts are foundry-processed CMOS switched-FET circuits that have charge capacities greater than 107 electrons and a single video output capable of 10-MHz data rates. The high quantum efficiency, tunable absorption wavelength, and broad operating temperature range of these large HgCdTe staring focal plane arrays give them significant advantages over competing sensors. The mature Producible Alternative to CdTe for Epitaxy-1 (PACE-1) technology, using sapphire detector substrates, has demonstrated 256 x 256 MWIR arrays with mean laboratory noise equivalent temperature difference (NETO) of 9 mK for a 4.9-micron cutoff wavelength, 40-micron pixel size, and 80-K operating temperature. RMS detector response nonuniformities are less than 4 percent, and pixel yields are greater than 99 percent. The newly developed PACE-3 process uses silicon for the detector substrate to eliminate completely the thermal mismatch with the silicon readout circuit. It has the potential for similar performance in even larger array sizes. A 640 x 480 hybrid array is under development.

  15. Hybrid image segmentation using watersheds

    NASA Astrophysics Data System (ADS)

    Haris, Kostas; Efstratiadis, Serafim N.; Maglaveras, Nicos; Pappas, Costas

    1996-02-01

    A hybrid image segmentation algorithm is proposed which combines edge- and region-based techniques through the morphological algorithm of watersheds. The algorithm consists of the following steps: (1) edge-preserving statistical noise reduction, (2) gradient approximation, (3) detection of watersheds on gradient magnitude image, and (4) hierarchical region merging (HRM) in order to get semantically meaningful segmentations. The HRM process uses the region adjacency graph (RAG) representation of the image regions. At each step, the most similar pair of regions is determined (minimum cost RAG edge), the regions are merged and the RAG is updated. Traditionally, the above is implemented by storing all the RAG edges in a priority queue (heap). We propose a significantly faster algorithm which maintains an additional graph, the most similar neighbor graph, through which the priority queue size and processing time are drastically reduced. The final segmentation is an image partition which, through the RAG, provides information that can be used by knowledge-based high level processes, i.e. recognition. In addition, this region based representation provides one-pixel wide, closed, and accurately localized contours/surfaces. Due to the small number of free parameters, the algorithm can be quite effectively used in interactive image processing. Experimental results obtained with 2D MR images are presented.

  16. 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.

  17. 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.

  18. 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.

  19. Passive cavitation imaging with ultrasound arrays

    PubMed Central

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

    2009-01-01

    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. PMID:20000921

  20. 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.

  1. 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

  2. Far-infrared imaging antenna arrays

    NASA Technical Reports Server (NTRS)

    Neikirk, D. P.; Rutledge, D. B.; Muha, M. S.; Park, H.; Yu, C.-X.

    1982-01-01

    A far-infrared monolithic imaging antenna array with diffraction-limited resolution has been demonstrated. The optical system is similar to an oil-immersion microscope, except that the position of the object and the image are interchanged. The array is a series of evaporated silver bow-tie antennas of 75 nm thick, spaced at 310 microns, on a fused-quartz substrate; the bow angle of 60 deg gives an impedance of 150 ohm to match to bismuth microbolometers. The measured responsivity of the array elements is 1-2 V/W at the relatively low bias of 1 mA. Previous measurements have shown that the bolometers are 1/f noise limited up to 100 kHz and that they have a frequency response of 5 MHz. The antenna array should be adequate for far-infrared plasma interferometer measurements.

  3. Complementary lattice arrays for coded aperture imaging

    NASA Astrophysics Data System (ADS)

    Ding, Jie; Noshad, Mohammad; Tarokh, Vahid

    2016-05-01

    In this work, we consider complementary lattice arrays in order to enable a broader range of designs for coded aperture imaging systems. We provide a general framework and methods that generate richer and more flexible designs than existing ones. Besides this, we review and interpret the state-of-the-art uniformly redundant arrays (URA) designs, broaden the related concepts, and further propose some new design methods.

  4. Image Enhancement with Polymer Grid Triode Arrays

    NASA Astrophysics Data System (ADS)

    Heeger, Alan J.; Heeger, David J.; Langan, John; Yang, Yang

    1995-12-01

    An array of polymer grid triodes connected by a common grid functions as a "plastic retina," providing local contrast gain control for image enhancement. This simple device, made from layers of conducting polymers, functions as an active resistive network that performs center-surround filtering. The polymer grid triode array with common grid is a continuous analog of the discrete approach of Mead, with a variety of fabrication advantages and significant savings in area within the unit cell of each pixel.

  5. Synthesized Bistatic Echo Imaging Using Phased Arrays

    NASA Astrophysics Data System (ADS)

    Soumekh, Mehrdad

    1990-01-01

    An object illuminated by a source produces a scattered signal; this signal depends upon both the source and the physical properties of the object. The problem of deducing coordinates, shape and/or certain physical properties of the object from the measurements of the returned signal is an inverse problem called echo imaging. The problem of echo imaging arises in medical imaging, remote sensing (radar; sonar; geophysical exploration), and non-destructive testing. In this paper, we address the problem of imaging an object form its returned signals using a phased array. Our approach is to exploit the array's various radiation patterns and the recordable portion of the returned signal's spectrum to generate the data base for this echo imaging system. Rapid steering of a phased array's radiation patterns can be achieved electronically. These steered waves can be utilized to synthesize waves with varying angles of propagation. In this case, the recorded returned signal for each direction of propagation can be viewed as data obtained by a bistatic array configuration. We first formulate the imaging problem for a plane wave source in a bistatic configuration. We utilize the two-way propagation time and amplitude of the returned signal to relate the object's properties, reflectivity function and coordinates, to the measured data (system modeling). This relationship is the basis for deducing the object's reflectivity function from the recorded data (inverse problem). We then extend these results for an arbitrary radiation pattern and synthesized radiation patterns generated by an array capable of beam steering in cross-range. We show that the recorded returned signals can be related to the spatial frequency contents of the reflectivity function. We also show that these array processing principles can be utilized to formulate a system model and inversion for synthetic aperture radar (SAR) imaging that incorporates wavefront curvature.

  6. 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.

  7. Plane wave imaging using phased array

    NASA Astrophysics Data System (ADS)

    Volker, Arno

    2014-02-01

    Phased arrays are often used for rapid inspections. Phased arrays can be used to synthesize different wave fronts. For imaging, focused wave fronts are frequently used. In order to build an image, the phased array has to be fired multiple times at the same location. Alternatively, different data acquisition configurations can be designed in combination with an imaging algorithm. The objective of this paper is to use the minimal amount of data required to construct an image. If a plane wave is synthesized, the region of interest is illuminated completely. For plane wave synthesis, all elements in the phase array are fired. This ensures a good signal to noise ratio. Imaging can be performed efficiently with a mapping algorithm in the wavenumber domain. The algorithm involves only two Fourier transforms and can therefore be extremely fast. The obtained resolution is comparable to conventional imaging algorithms. This work investigates the potential and limitations of this mapping algorithm on simulated data. With this approach, frame rates of more than 1 kHz can be achieved.

  8. Dual Frequency Coil Array for MR Imaging

    NASA Astrophysics Data System (ADS)

    Amador-Baheza, R.; Sacristan-Rock, E.; Rodríguez, A. O.

    2002-08-01

    An array coil to perform in vivo Magnetic Resonance Imaging and Spectroscopy was developed to study the intestinal wall. It consisted of two surface rectangular-shaped coils mounted on cylindrical structure forming an orthogonal assembly. Since this design is intended to generate images and spectra, each element was tuned to a different resonant frequency: a) imaging: 200 MHz (1H) and b) spectroscopy: 81 MHz (31P). However, at this stage of the research, imaging experiments were only conducted on a Bruker 4.7 Tesla animal system. High-resolution images were obtained from a saline filled phantom and from the intestinal wall of a fully anaesthetised rabbit. The dual frequency coil array can be used to study the pathophysiology of intestinal ischemia.

  9. A Prototype Imager for the CHARA Array

    NASA Astrophysics Data System (ADS)

    Turner, Nils Henning

    1998-11-01

    Traditional methods of data collection in active fringe tracking Michelson stellar interferometers involve logging and analyzing the signals within the fringe tracking system for the scientific information about the object being observed. While these methods are robust and have produced excellent scientific results, they become more problematic as next-generation Michelson stellar interferometers are built with more telescopes and the aim of performing routine imaging. The Center for High Angular Resolution Astronomy (CHARA) Array is one such next-generation instrument presently under construction on Mount Wilson, north of Los Angeles, California. The CHARA Array will feature a separation of the tasks of active fringe tracking and imaging, thereby increasing the bandwidth, sensitivity, and data acquisition rate. Presented is a prototype version of an imager for the CHARA Array. The prototype imager employs single-mode fiber optic strands to convey the light from simulated telescopes to a smaller, non-redundant, remapped pupil plane, which in turn feeds a low resolution prism spectrograph. The spectrograph features two cylindrical optical elements whose net effect is to focus the light to a smaller plate scale in the spectral dimension than in the orthogonal spatial dimension. The actual Array imager will build on lessons learned from the prototype and will include capability for five telescopes, further degrees of freedom in adjustment, a computer interface, and automatic intensity calibration.

  10. 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

  11. Spin scan tomographic array-based imager.

    PubMed

    Hovland, Harald

    2014-12-29

    This work presents a novel imaging device based on tomographic reconstruction. Similar in certain aspects to the earlier presented tomographic scanning (TOSCA) principle, it provides several important enhancements. The device described generates a stream of one-dimensional projections from a linear array of thin stripe detectors onto which the (circular) image of the scene is rotated. A two-dimensional image is then reproduced from the one-dimensional signals using tomographic processing techniques. A demonstrator is presented. Various aspects of the design and construction are discussed, and resulting images and movies are presented. PMID:25607168

  12. 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.

  13. Hybrid Array of Gamma Ray Detectors (HAGRiD)

    NASA Astrophysics Data System (ADS)

    Smith, Karl; Grzywacz, R.; Jones, K. L.; Munoz, S.; Baugher, T.; Cizewski, J. A.; Ratkiewicz, A.; Pain, S. D.

    2015-10-01

    Transfer reactions and beta-decay studies are powerful tools to study nuclear structure and to provide insight into astrophysically important reactions that may be difficult to measure directly. Both types of studies are enhanced immensely by measuring a particle-gamma coincidence. For transfer reactions, gamma-ray measurements improve the resolution, aid in channel selection and lifetime measurements. To achieve these coincidences the Hybrid Array of Gamma Ray Detectors (HAGRiD) is being designed and constructed. This array would be coupled with the Oak Ridge Rutgers Barrel Array (ORRUBA) of silicon detectors, the Versatile Array of Neutron Detectors at Low Energy (VANDLE) and beta detection scintillators. Detector systems providing a particle-gamma coincidence have previously compromised the charged-particle angular resolution due to compact geometries used to increase the gamma efficiency. HAGRiD will be coupled with ORRUBA such that resolution is not sacrificed, requiring the new array to provide improved resolution and efficiency over NaI and increased portability and flexibility over germanium detectors; therefore, we have chosen to use LaBr3(Ce) crystals. We demonstrate the advantages of a coupled detector system and discuss the current status of the project.

  14. Image Rotation Correction With CORDIC Array Processor

    NASA Astrophysics Data System (ADS)

    Shyu, Keh-Hwa; Jeng, Bor-Shenn; Jou, I.-Chang; Ting, Pei-Yih

    1988-10-01

    In the document analysis system or the understanding system[1,2], the rotation of the document's image will cause optical character recognition error. Then the document must be scanned and recognized again. This phenomenon will degrade the performance of the automatic document input system. In this paper, we propose a method to estimate the unexpected rotational angle of the image. And we suggest using the pipelined CORDIC array processor architecture to rotate the image back quickly. Thus the performance of the automatic document input system will increase.

  15. Image enhancement with polymer grid triode arrays

    SciTech Connect

    Heeger, A.J.; Heeger, D.J.; Langan, J.

    1995-12-08

    An array of polymer grid triodes connected by a common grid functions as a {open_quotes}plastic retina,{close_quotes} providing local contrast gain control for image enhancement. This simple device, made from layers of conducting polymers, functions as an active resistive network that performs center-surround filtering. The polymer grid triode array with common grid is a continuous analog of the discrete approach of Mead, with a variety of fabrication advantages and significant savings in area within the unit cell of each pixel. 6 refs., 4 figs.

  16. Extended arrays for nonlinear susceptibility magnitude imaging.

    PubMed

    Ficko, Bradley W; Giacometti, Paolo; Diamond, Solomon G

    2015-10-01

    This study implements nonlinear susceptibility magnitude imaging (SMI) with multifrequency intermodulation and phase encoding. An imaging grid was constructed of cylindrical wells of 3.5-mm diameter and 4.2-mm height on a hexagonal two-dimensional 61-voxel pattern with 5-mm spacing. Patterns of sample wells were filled with 40-μl volumes of Fe3O4 starch-coated magnetic nanoparticles (mNPs) with a hydrodynamic diameter of 100 nm and a concentration of 25 mg/ml. The imaging hardware was configured with three excitation coils and three detection coils in anticipation that a larger imaging system will have arrays of excitation and detection coils. Hexagonal and bar patterns of mNP were successfully imaged (R2>0.9) at several orientations. This SMI demonstration extends our prior work to feature a larger coil array, enlarged field-of-view, effective phase encoding scheme, reduced mNP sample size, and more complex imaging patterns to test the feasibility of extending the method beyond the pilot scale. The results presented in this study show that nonlinear SMI holds promise for further development into a practical imaging system for medical applications. PMID:26124044

  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. The SORDS trimodal imager detector arrays

    NASA Astrophysics Data System (ADS)

    Wakeford, Daniel; Andrews, H. R.; Clifford, E. T. H.; Li, Liqian; Bray, Nick; Locklin, Darren; Hynes, Michael V.; Toolin, Maurice; Harris, Bernard; McElroy, John; Wallace, Mark; Lanza, Richard

    2009-05-01

    The Raytheon Trimodal Imager (TMI) uses coded aperture and Compton imaging technologies as well as the nonimaging shadow technology to locate an SNM or radiological threat in the presence of background. The heart of the TMI is two arrays of NaI crystals. The front array serves as both a coded aperture and the first scatterer for Compton imaging. It is made of 35 5x5x2" crystals with specially designed low profile PMTs. The back array is made of 30 2.5x3x24" position-sensitive crystals which are read out at both ends. These crystals are specially treated to provide the required position resolution at the best possible energy resolution. Both arrays of detectors are supported by aluminum superstructures. These have been efficiently designed to allow a wide field of view and to provide adequate support to the crystals to permit use of the TMI as a vehicle-mounted, field-deployable system. Each PMT has a locally mounted high-voltage supply that is remotely controlled. Each detector is connected to a dedicated FPGA which performs automated gain alignment and energy calibration, event timing and diagnostic health checking. Data are streamed, eventby- event, from each of the 65 detector FPGAs to one master FPGA. The master FPGA acts both as a synchronization clock, and as an event sorting unit. Event sorting involves stamping events as singles or as coincidences, based on the approximately instantaneous detector hit pattern. Coincidence determination by the master FPGA provides a pre-sorting for the events that will ultimately be used in the Compton imaging and coded aperture imaging algorithms. All data acquisition electronics have been custom designed for the TMI.

  19. The hybrid energy spectrum of Telescope Array's Middle Drum Detector and surface array

    NASA Astrophysics Data System (ADS)

    Abbasi, R. U.; Abe, M.; Abu-Zayyad, T.; Allen, M. G.; Anderson, R.; Azuma, R.; Barcikowski, E.; Belz, J. W.; Bergman, D. R.; Blake, S. A.; Cady, R.; Chae, M. J.; Cheon, B. G.; Chiba, J.; Chikawa, M.; Cho, W. R.; Fujii, T.; Fukushima, M.; Goto, T.; Hanlon, W.; Hayashi, Y.; Hayashida, N.; Hibino, K.; Honda, K.; Ikeda, D.; Inoue, N.; Ishii, T.; Ishimori, R.; Ito, H.; Ivanov, D.; Jui, C. C. H.; Kadota, K.; Kakimoto, F.; Kalashev, O.; Kasahara, K.; Kawai, H.; Kawakami, S.; Kawana, S.; Kawata, K.; Kido, E.; Kim, H. B.; Kim, J. H.; Kim, J. H.; Kitamura, S.; Kitamura, Y.; Kuzmin, V.; Kwon, Y. J.; Lan, J.; Lim, S. I.; Lundquist, J. P.; Machida, K.; Martens, K.; Matsuda, T.; Matsuyama, T.; Matthews, J. N.; Minamino, M.; Mukai, K.; Myers, I.; Nagasawa, K.; Nagataki, S.; Nakamura, T.; Nonaka, T.; Nozato, A.; Ogio, S.; Ogura, J.; Ohnishi, M.; Ohoka, H.; Oki, K.; Okuda, T.; Ono, M.; Oshima, A.; Ozawa, S.; Park, I. H.; Pshirkov, M. S.; Rodriguez, D. C.; Rubtsov, G.; Ryu, D.; Sagawa, H.; Sakurai, N.; Sampson, A. L.; Scott, L. M.; Shah, P. D.; Shibata, F.; Shibata, T.; Shimodaira, H.; Shin, B. K.; Shin, H. S.; Smith, J. D.; Sokolsky, P.; Springer, R. W.; Stokes, B. T.; Stratton, S. R.; Stroman, T. A.; Suzawa, T.; Takamura, M.; Takeda, M.; Takeishi, R.; Taketa, A.; Takita, M.; Tameda, Y.; Tanaka, H.; Tanaka, K.; Tanaka, M.; Thomas, S. B.; Thomson, G. B.; Tinyakov, P.; Tkachev, I.; Tokuno, H.; Tomida, T.; Troitsky, S.; Tsunesada, Y.; Tsutsumi, K.; Uchihori, Y.; Udo, S.; Urban, F.; Vasiloff, G.; Wong, T.; Yamane, R.; Yamaoka, H.; Yamazaki, K.; Yang, J.; Yashiro, K.; Yoneda, Y.; Yoshida, S.; Yoshii, H.; Zollinger, R.; Zundel, Z.

    2015-08-01

    The Telescope Array experiment studies ultra high energy cosmic rays using a hybrid detector. Fluorescence telescopes measure the longitudinal development of the extensive air shower generated when a primary cosmic ray particle interacts with the atmosphere. Meanwhile, scintillator detectors measure the lateral distribution of secondary shower particles that hit the ground. The Middle Drum (MD) fluorescence telescope station consists of 14 telescopes from the High Resolution Fly's Eye (HiRes) experiment, providing a direct link back to the HiRes measurements. Using the scintillator detector data in conjunction with the telescope data improves the geometrical reconstruction of the showers significantly, and hence, provides a more accurate reconstruction of the energy of the primary particle. The Middle Drum hybrid spectrum is presented and compared to that measured by the Middle Drum station in monocular mode. Further, the hybrid data establishes a link between the Middle Drum data and the surface array. A comparison between the Middle Drum hybrid energy spectrum and scintillator Surface Detector (SD) spectrum is also shown.

  20. Simultaneous multispectral imaging using lenslet arrays

    NASA Astrophysics Data System (ADS)

    Hinnrichs, Michele; Jensen, James

    2013-03-01

    There is a need for small compact multispectral and hyperspectral imaging systems that simultaneously images in many spectral bands across the infrared spectral region from short to long-wave infrared. This is a challenge for conventional optics and usually requires large, costly and complex optical systems. However, with the advances in materials and photolithographic technology, Micro-Optical-Electrical-Machine-Systems (MOEMS) can meet these goals. In this paper Pacific Advanced Technology and ECBC will present the work that we are doing under a SBIR contract to the US Army using a MOEMS based diffractive optical lenslet array to perform simultaneous multispectral and hyperspectral imaging with relatively high spatial resolution. Under this program we will develop a proof of concept system that demonstrates how a diffractive optical (DO) lenslet array can image 1024 x 1024 pixels in 16 colors every frame of the camera. Each color image has a spatial resolution of 256 x 256 pixels with an IFOV of 1.7 mrads and FOV of 25 degrees. The purpose of this work is to simultaneously image multiple colors each frame and reduce the temporal changes between colors that are apparent in sequential multispectral imaging. Translating the lenslet array will collect hyperspectral image data cubes as will be explained later in this paper. Because the optics is integrated with the detector the entire multispectral/hyperspectral system can be contained in a miniature package. The spectral images are collected simultaneously allowing high resolution spectral-spatial-temporal information each frame of the camera. Thus enabling the implementation of spectral-temporal-spatial algorithms in real-time with high sensitivity for the detection of weak signals in a high background clutter environment with low sensitivity to camera motion. Using MOEMS actuation the DO lenslet array is translated along the optical axis to complete the full hyperspectral data cube in just a few frames of the

  1. 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.

  2. 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.

  3. Development of segmented semiconductor arrays for quantum imaging

    NASA Astrophysics Data System (ADS)

    Mikulec, B.; Medipix2 Collaboration

    2003-09-01

    The field of pixel detectors has grown strongly in recent years through progress in CMOS technology, which permits many hundreds of transistors to be implemented in an area of 50-200 μm 2. Pulse processing electronics with noise of the order of 100 e - RMS permits to distinguish photons of a few kilo-electron-Volts from background noise. Techniques are under development, which should allow single chip systems (area ˜1 cm 2) to be extended to larger areas. This paper gives an introduction into the concept of quantum imaging using direct conversion in segmented semiconductor arrays. An overview of projects from this domain using strip, pad and in particular hybrid pixel detectors will be presented. One of these projects, the Medipix project, is described in more detail. The effect of different correction methods like threshold adjustment and flat field correction is illustrated and new measurement results and images are presented.

  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. Smart pixel imaging with computational-imaging arrays

    NASA Astrophysics Data System (ADS)

    Fernandez-Cull, Christy; Tyrrell, Brian M.; D'Onofrio, Richard; Bolstad, Andrew; Lin, Joseph; Little, Jeffrey W.; Blackwell, Megan; Renzi, Matthew; Kelly, Mike

    2014-07-01

    Smart pixel imaging with computational-imaging arrays (SPICA) transfers image plane coding typically realized in the optical architecture to the digital domain of the focal plane array, thereby minimizing signal-to-noise losses associated with static filters or apertures and inherent diffraction concerns. MIT Lincoln Laboratory has been developing digitalpixel focal plane array (DFPA) devices for many years. In this work, we leverage legacy designs modified with new features to realize a computational imaging array (CIA) with advanced pixel-processing capabilities. We briefly review the use of DFPAs for on-chip background removal and image plane filtering. We focus on two digital readout integrated circuits (DROICS) as CIAs for two-dimensional (2D) transient target tracking and three-dimensional (3D) transient target estimation using per-pixel coded-apertures or flutter shutters. This paper describes two DROICs - a SWIR pixelprocessing imager (SWIR-PPI) and a Visible CIA (VISCIA). SWIR-PPI is a DROIC with a 1 kHz global frame rate with a maximum per-pixel shuttering rate of 100 MHz, such that each pixel can be modulated by a time-varying, pseudorandom, and duo-binary signal (+1,-1,0). Combining per-pixel time-domain coding and processing enables 3D (x,y,t) target estimation with limited loss of spatial resolution. We evaluate structured and pseudo-random encoding strategies and employ linear inversion and non-linear inversion using total-variation minimization to estimate a 3D data cube from a single 2D temporally-encoded measurement. The VISCIA DROIC, while low-resolution, has a 6 kHz global frame rate and simultaneously encodes eight periodic or aperiodic transient target signatures at a maximum rate of 50 MHz using eight 8-bit counters. By transferring pixel-based image plane coding to the DROIC and utilizing sophisticated processing, our CIAs enable on-chip temporal super-resolution.

  6. 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.

  7. 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.

  8. Tomographic image reconstruction using systolic array algorithms

    SciTech Connect

    Azevedo, S.G.; DeGroot, A.J.; Schneberk, D.J.; Brase, J.M.; Martz, H.E.; Jain, A.K.; Current, K.W.; Hurst, P.J.

    1988-12-22

    Image reconstruction for Computed Tomography (CT) is a time consuming operation on current uniprocessor computers and even on array processors. This is particularly true for three-dimensional data sets or for limited-data reconstructions requiring iterative procedures. In these cases, the projection operation (Radon transform) and its inverse (filtered back-projection) are major computational tasks that are performed many times. Multiprocessor computers, especially in systolic array configurations, can provide dramatic improvements in reconstruction times at reasonable costs. An in-house systolic processor, called SPRINT, has been programmed to demonstrate these improved speeds while achieving near 100% efficiency of all processor elements. We report on these results in this paper. In addition, two proposed hardware implementations of a new architecture are shown to have even greater speedup possibilities. One, using standard DSP chips, has been simulated to give a factor of three improvement over SPRINT, while the other, using custom VLSI that is now in the early stages of design, could potentially perform 512/sup 2/ reconstructions at video rates (100 times further speedup). These processors are also interconnected in a systolic array configuration. Experimental and projected results, with future plans, are also reported in this paper. 11 refs., 5 figs., 1 tab.

  9. 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.

  10. Mutation Screening and Array Comparative Genomic Hybridization Using a 180K Oligonucleotide Array in VACTERL Association

    PubMed Central

    Winberg, Johanna; Gustavsson, Peter; Papadogiannakis, Nikos; Sahlin, Ellika; Bradley, Frideborg; Nordenskjöld, Edvard; Svensson, Pär-Johan; Annerén, Göran; Iwarsson, Erik; Nordgren, Ann; Nordenskjöld, Agneta

    2014-01-01

    In order to identify genetic causes of VACTERL association (V vertebral defects, A anorectal malformations, C cardiac defects, T tracheoesofageal fistula, E esophageal atresia, R renal anomalies, L limb deformities), we have collected DNA samples from 20 patients diagnosed with VACTERL or with a VACTERL-like phenotype as well as samples from 19 aborted fetal cases with VACTERL. To investigate the importance of gene dose alterations in the genetic etiology of VACTERL association we have performed a systematic analysis of this cohort using a 180K array comparative genomic hybridization (array-CGH) platform. In addition, to further clarify the significance of PCSK5, HOXD13 and CHD7 genes in the VACTERL phenotype, mutation screening has been performed. We identified pathogenic gene dose imbalances in two fetal cases; a hemizygous deletion of the FANCB gene and a (9;18)(p24;q12) unbalanced translocation. In addition, one pathogenic mutation in CHD7 was detected, while no apparent disease-causing mutations were found in HOXD13 or PCSK5. Our study shows that although large gene dose alterations do not seem to be a common cause in VACTERL association, array-CGH is still important in clinical diagnostics to identify disease cause in individual cases. PMID:24416387

  11. Hybrid SPECT/CT imaging in neurology.

    PubMed

    Ciarmiello, Andrea; Giovannini, Elisabetta; Meniconi, Martina; Cuccurullo, Vincenzo; Gaeta, Maria Chiara

    2014-01-01

    In recent years, the SPECT/CT hybrid modality has led to a rapid development of imaging techniques in nuclear medicine, opening new perspectives for imaging staff and patients as well. However, while, the clinical role of positron emission tomography-computed tomography (PET-CT) is well consolidated, the diffusion and the consequent value of single-photon emission tomography-computed tomography (SPECT-CT) has yet to be weighed, Hence, there is a need for a careful analysis, comparing the "potential" benefits of the hybrid modality with the "established" ones of the standalone machine. The aim of this article is to analyze the impact of this hybrid tool on the diagnosis of diseases of the central nervous system, comparing strengths and weaknesses of both modalities through the use of SWOT analysis. PMID:25143053

  12. Hybrid Compton camera/coded aperture imaging system

    DOEpatents

    Mihailescu, Lucian; Vetter, Kai M.

    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.

  13. 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.

  14. Operation and test of hybridized silicon p-i-n arrays using open-source array control hardware and software

    NASA Astrophysics Data System (ADS)

    Moore, Andrew C.; Ninkov, Zoran; Burley, Gregory S.; Forrest, William J.; McMurtry, Craig W.; Avery, Lars E.

    2003-05-01

    A system for controlling and testing high-resolution non-destructive astronomical imagers was constructed using open-source components, both hardware and software. The open-source electronics design, originated by Carnegie Observatories (OCIW) for CCD cameras, was modified, assembled, and augmented with new circuitry which facilitates monitoring of voltages and currents. The electronics was run from Python user interface software based on a design from the University of Rochester. This new software utilized the Numarray and pyFITS modules developed at the Space Telescope Science Institute (STScI). Interfacing to the "dv" FITS image analysis package from the NASA IRTF was also implemented. Python (the STScI language of choice) was used as the primary language for systems integration, scripts for data acquisition, and scripts for data analysis. The DSP clocking software was a mixture of C and Motorola 56303 assembly. An interrupt-driven kernel-mode PCI device driver for Red Hat Linux was written in C, and used the PC processor and memory for image processing and acquisition. Two 1Κ × 1Κ Raytheon SB226-based hybridized silicon p-i-n arrays were operated and tested with the new system at temperatures as low as 10K. Signal path gain, node capacitance, well depth, dark current, and MTF measurements were made and are presented here.

  15. 802GHz integrated horn antennas imaging array

    NASA Astrophysics Data System (ADS)

    Ali-Ahmad, Walid Y.; Rebeiz, Gabriel M.; Dave, Hemant; Chin, Gordon

    1991-05-01

    Pattern measurements at 802GHz of a single element in 256-element integrated horn imaging array are presented. The integrated-horn antenna consists of a dipole-antenna suspended on a 1-micron dielectric membrane inside a pyramidal cavity etched in silicon. The theoretical far-field patterns, calculated using reciprocity and Floquet-modes representation of the free-space field, agree well with the measured far-field patterns at 802GHz. The associated directivity for a 1.40 lambda horn aperture, calculated from the measured E and H-plane patterns is 12.3dB + or - 0.2dB. This work demonstrates that high-efficiency integrated-horn antennas are easily scalable to terahertz frequencies and could be used for radio-astronomical and plasma-diagnostic applications.

  16. Development of a gallium-doped germanium far-infrared photoconductor direct hybrid two-dimensional array.

    PubMed

    Fujiwara, Mikio; Hirao, Takanori; Kawada, Mitsunobu; Shibai, Hiroshi; Matsuura, Shuji; Kaneda, Hidehiro; Patrashin, Mikhail; Nakagawa, Takao

    2003-04-20

    To our knowledge, we are the first to successfully report a direct hybrid two-dimensional (2D) detector array in the far-infrared region. Gallium-doped germanium (Ge:Ga) has been used extensively to produce sensitive far-infrared detectors with a cutoff wavelength of approximately equal to 110 microm (2.7 THz). It is widely used in the fields of astronomy and molecular and solid spectroscopy. However, Ge:Ga photoconductors must be cooled below 4.2 K to reduce thermal noise, and this operating condition makes it difficult to develop a large format array because of the need for a warm amplifier. Development of Ge:Ga photoconductor arrays to take 2D terahertz images is now an important target in such research fields as space astronomy. We present the design of a 20 x 3 Ge:Ga far-infrared photoconductor array directly hybridized to a Si p-type metal-oxide-semiconductor readout integrated circuit using indium-bump technology. The main obstacles in creating this 2D array were (1) fabricating a monolithic Ge:Ga 2D array with a longitudinal configuration, (2) developing a cryogenic capacitive transimpedance amplifer, and (3) developing a technology for connecting the detector to the electronics. With this technology, a prototype Ge:Ga photoconductor with a direct hybrid structure has shown a responsivity as high as 14.6 A/W and a minimum detectable power of 5.6 x 10(-17) W for an integration time of 0.14 s when it was cooled to 2.1 K. Its noise is limited by the readout circuit with 20 microV/Hz(1/2) at 1 Hz. Vibration and cooling tests demonstrated that this direct hybrid structure is strong enough for spaceborne instruments. This detector array will be installed on the Japanese infrared satellite ASTRO-F. PMID:12716158

  17. Realization of hybrid compressive imaging strategies.

    PubMed

    Li, Yun; Sankaranarayanan, Aswin C; Xu, Lina; Baraniuk, Richard; Kelly, Kevin F

    2014-08-01

    The tendency of natural scenes to cluster around low frequencies is not only useful in image compression, it also can prove advantageous in novel infrared and hyperspectral image acquisition. In this paper, we exploit this signal model with two approaches to enhance the quality of compressive imaging as implemented in a single-pixel compressive camera and compare these results against purely random acquisition. We combine projection patterns that can efficiently extract the model-based information with subsequent random projections to form the hybrid pattern sets. With the first approach, we generate low-frequency patterns via a direct transform. As an alternative, we also used principal component analysis of an image library to identify the low-frequency components. We present the first (to the best of our knowledge) experimental validation of this hybrid signal model on real data. For both methods, we acquire comparable quality of reconstructions while acquiring only half the number of measurements needed by traditional random sequences. The optimal combination of hybrid patterns and the effects of noise on image reconstruction are also discussed. PMID:25121526

  18. 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.

  19. 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.

  20. DEPMOS arrays for x-ray imaging

    NASA Astrophysics Data System (ADS)

    Lutz, Gerhard; Richter, Rainer H.; Strueder, Lothar

    2000-07-01

    For future x-ray satellite missions and other applications we propose a novel sensor which is based on the `DEPleted Field Effect Transistor (DEPFET)'. MOS-type DEPFETs (DEPMOS) are employed in prototype designs of pixel detectors ready for production. The device operated on a fully depleted silicon wafer allows an internal charge amplification directly above the position where the signal conversion takes place. A very low gate capacitance of the DEPMOS transistor leads to low noise amplification. In contrast to CCDs neither transfer loss nor `out of time events' can occur in a DEPFET-array. Fast imaging and low power consumption can be achieved by a row by row selection mode. The signal charge stored in a potential minimum below the transistor channel can be read out non destructively and repeatedly. By shifting the charge between two neighboring DEPMOS amplifiers the repeated signal readout leads to significant noise reduction. Concept, design and device simulations are presented and consequences of the expected properties for applications in x-ray imaging are discussed.

  1. Image analysis in comparative genomic hybridization

    SciTech Connect

    Lundsteen, C.; Maahr, J.; Christensen, B.

    1995-01-01

    Comparative genomic hybridization (CGH) is a new technique by which genomic imbalances can be detected by combining in situ suppression hybridization of whole genomic DNA and image analysis. We have developed software for rapid, quantitative CGH image analysis by a modification and extension of the standard software used for routine karyotyping of G-banded metaphase spreads in the Magiscan chromosome analysis system. The DAPI-counterstained metaphase spread is karyotyped interactively. Corrections for image shifts between the DAPI, FITC, and TRITC images are done manually by moving the three images relative to each other. The fluorescence background is subtracted. A mean filter is applied to smooth the FITC and TRITC images before the fluorescence ratio between the individual FITC and TRITC-stained chromosomes is computed pixel by pixel inside the area of the chromosomes determined by the DAPI boundaries. Fluorescence intensity ratio profiles are generated, and peaks and valleys indicating possible gains and losses of test DNA are marked if they exceed ratios below 0.75 and above 1.25. By combining the analysis of several metaphase spreads, consistent findings of gains and losses in all or almost all spreads indicate chromosomal imbalance. Chromosomal imbalances are detected either by visual inspection of fluorescence ratio (FR) profiles or by a statistical approach that compares FR measurements of the individual case with measurements of normal chromosomes. The complete analysis of one metaphase can be carried out in approximately 10 minutes. 8 refs., 7 figs., 1 tab.

  2. 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.

  3. Advances in passive imaging elements with micromirror array

    NASA Astrophysics Data System (ADS)

    Maekawa, Satoshi; Nitta, Kouichi; Matoba, Osamu

    2008-02-01

    We have proposed a new passive imaging optics which consists of a grid array of micro roof mirrors working as dihedral corner reflectors. Although this element forms mirror-like images at opposite side of objects, the images are real. Because the imaging principle of the proposed element is based on accumulation of rays, the design of each light path makes many kinds of devices possible. So, we propose two variations of such a device. One device consists of an array of micro retroreflectors and a half mirror, and it can also form real mirror-like images. The advantage of this device is wide range of view, because the displacement of each retororeflector is not limited on a plane unlike the roof mirror grid array. The other consists of an array of long dihedral corner reflectors. Although this structure has been already known as a roof mirror array, it can be used for imaging. This device forms two heterogeneous images. One is real at the same side of an object, and the other is virtual at the opposite side. This is a conjugate imaging optics of a slit mirror array whose mirror surface is perpendicular to the device surface. The advantage of a roor mirror array is that the real image has horizontal parallax and can be seen in air naturally.

  4. In-situ synthesis of photocatalytic CuAl2O4-Cu hybrid nanorod arrays.

    PubMed

    Ding, Dawei; Long, Mingce; Cai, Weimin; Wu, Yahui; Wu, Deyong; Chen, Chao

    2009-06-28

    Copper aluminate-copper hybrid nanorod arrays possessing superior visible-light driven photocatalytic properties were synthesized inside porous anodic aluminum oxide (AAO) under mild electrochemical conditions. PMID:19521617

  5. Array Comparative Genomic Hybridizations: Assessing the ability to recapture evolutionary relationships using an in silico approach

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Comparative Genomic Hybridization (CGH) with DNA microarrays has many biological applications including surveys of copy number changes in tumorigenesis, species detection and identification, and functional genomics studies among related organisms. Array CGH has also been used to infer phylogenetic r...

  6. Addressable nanowell arrays formed using reversibly sealable hybrid elastomer-metal stencils.

    PubMed

    Pla-Roca, Mateu; Leulmi, Rym Feriel; Djambazian, Haig; Sundararajan, Saravanan; Juncker, David

    2010-05-01

    There are two major array formats used in life science research and biomedical analysis. The first is the microwell plate format with millimeter-sized wells each with microliter capacity addressed individually and repeatedly during experiments. The second is the microarray format with micrometer-sized spots that are patterned initially but not addressable individually thereafter. Here, we present an addressable nanoliter-well plate with micrometer sized wells that combines the advantages of the two array formats. The nanowells are formed by reversibly sealing a steel stencil featuring an array of micrometer-scale openings to an optically transparent substrate. The nanowells have a capacity of approximately 1 nL, are approximately 140 microm in diameter, and are arrayed at a density of 1600 wells cm(-2). A soft polymer is patterned photolithographically around each opening so as to form a microgasket for pressure sensitive, liquid tight, and reversible sealing to any type of smooth substrate, either hydrophilic or hydrophobic. The rigidity of the steel prevents the distortion that occurs in soft, all-polymeric stencils and permits accurate registration across the entire array, which in turn allows for repeated, individual addressing of wells using an inkjet spotter. The stencils are used to pattern cells, make protein microarrays, and create nanowells on surfaces to study reverse transfection by first spotting plasmids encoding fluorescent proteins into the wells, seeding cells, and monitoring the transfection of the cells in real time using time-lapse imaging. The hybrid elastomer-metal stencils (HEMSs) are versatile and useful for multiplexed analysis of drugs, biomolecules, and cells with microarray density. PMID:20377190

  7. 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.

  8. Imaging antenna array at 119 microns. [for plasma diagnostics

    NASA Technical Reports Server (NTRS)

    Neikirk, N. P.; Tong, P. P.; Putledge, D. B.; Park, H.; Young, P. E.

    1982-01-01

    A focal-plane imaging antenna array has been demonstrated at 119 microns. The array is a line of evaporated silver bow-tie antennas with bismuth microbolometer detectors on a silicon substrate. Radiation is coupled into the array by a lens placed on the back of the substrate. The bolometers are thermally isolated from the silicon substrate with a half-micron layer of polyimide. The array performance is demonstrated by coherent imaging of a series of holes at half the diffraction-limited cut-off frequency.

  9. 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.

  10. Hybrid imaging is the future of molecular imaging

    PubMed Central

    Hicks, RJ; Lau, EWF; Binns, DS

    2007-01-01

    Correlative imaging has long been used in clinical practice and particularly for the interpretation of nuclear medicine studies wherein detailed anatomical information is often lacking. Previously, side-by-side comparison or software co-registration techniques were applied but suffered from technical limitations related to the differing geometries of the imaging equipment, differences in the positioning of patients and displacement of mobile structures between studies. The development of the first hybrid PET and CT device struck a chord with the medical imaging community that is still ringing loudly throughout the world. So successful has been the concept of PET-CT that none of the major medical imaging manufacturers now offers stand-alone PET scanners. Following close behind this success, SPECT-CT devices have recently been adopted by the nuclear medicine community, already compelled by the benefits of hybrid imaging through their experience with PET-CT. Recent reports of adaptation of PET detectors to operate within the strong magnetic field of MRI scanners have generated further enthusiasm. Prototype PET-MRI devices are now in development. The complementary anatomical, functional and molecular information provided by these techniques can now be presented in an intuitive and aesthetically-pleasing format. This has made end-users more comfortable with the results of functional imaging techniques than when the same information is presented independently. Despite the primacy of anatomical imaging for locoregional disease definition, the molecular characterisation available from PET and SPECT offers unique complementary information for cancer evaluation. A new era of cancer imaging, when hybrid imaging will be the primary diagnostic tool, is approaching. PMID:21614291

  11. Cd1-xZnxTe detector imaging array

    NASA Astrophysics Data System (ADS)

    Butler, Jack F.; Friesenhahn, Stan J.; Lingren, Clinton L.; Apotovsky, Boris A.; Doty, F. P.; Ashburn, William L.; Dillon, William P.

    1993-09-01

    A prototype portable gamma ray camera using 32 X 32 channels was developed. An experimental 3 X 3 sub-array of 5 mm X 5 mm CZT detectors was fabricated for use in system checkout and to investigate the applicability of CZT imaging arrays to nuclear medical imaging. Experiments were carried out to make a direct comparison of the imaging capabilities of the CZT sub-array with a state-of-the-art Anger camera. In a linespread study using a Tc-99m source embedded in a tissue equivalent absorber, contrasts of 9.5 for the CZT array and 3.4 for the Anger camera were observed. In a dynamic imaging experiment, the CZT imager appeared to have comparable resolution to and be somewhat more regular than the Anger camera.

  12. Role of Hybrid Brain Imaging in Neuropsychiatric Disorders.

    PubMed

    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

  13. HOPIS: hybrid omnidirectional and perspective imaging system for mobile robots.

    PubMed

    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

  14. 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

  15. 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

  16. 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

  17. Volumetric imaging with an amplitude-steered array.

    PubMed

    Frazier, Catherine H; Hughes, W Jack; O'Brien, William D

    2002-12-01

    Volumetric acoustic imaging is desirable for the visualization of underwater objects and structures; however, the implementation of a volumetric imaging system is difficult due to the high channel count of a fully populated two-dimensional array. Recently, a linear amplitude-steered array with a reduced electronics requirement was presented, which is capable of collecting a two-dimensional set of data with a single transmit pulse. In this study, we demonstrate the use of the linear amplitude-steered array and associated image formation algorithms for collecting and displaying volumetric data; that is, proof of principle of the amplitude-steering concept and the associated image formation algorithms is demonstrated. Range and vertical position are obtained by taking advantage of the frequency separation of a vertical linear amplitude-steered array. The third dimension of data is obtained by rotating the array such that the mainlobe is mechanically steered in azimuth. Data are collected in a water tank at the Pennsylvania State University Applied Research Laboratory for two targets: a ladder and three pipes. These data are the first experimental data collected with an amplitude-steered array for the purposes of imaging. The array is 10 cm in diameter and is operated in the frequency range of 80 to 304 kHz. Although the array is small for high-resolution imaging at these frequencies, the rungs of the ladder are recognizable in the images. The three pipes are difficult to discern in two of the projection images; however, the pipes separated in range are clear in the image showing vertical position versus range. The imaging concept is demonstrated on measured data, and the simulations agree well with the experimental results. PMID:12508995

  18. Volumetric imaging with an amplitude-steered array

    NASA Astrophysics Data System (ADS)

    Frazier, Catherine H.; Hughes, W. Jack; O'Brien, William D.

    2002-12-01

    Volumetric acoustic imaging is desirable for the visualization of underwater objects and structures; however, the implementation of a volumetric imaging system is difficult due to the high channel count of a fully populated two-dimensional array. Recently, a linear amplitude-steered array with a reduced electronics requirement was presented, which is capable of collecting a two-dimensional set of data with a single transmit pulse. In this study, we demonstrate the use of the linear amplitude-steered array and associated image formation algorithms for collecting and displaying volumetric data; that is, proof of principle of the amplitude-steering concept and the associated image formation algorithms is demonstrated. Range and vertical position are obtained by taking advantage of the frequency separation of a vertical linear amplitude-steered array. The third dimension of data is obtained by rotating the array such that the mainlobe is mechanically steered in azimuth. Data are collected in a water tank at the Pennsylvania State University Applied Research Laboratory for two targets: a ladder and three pipes. These data are the first experimental data collected with an amplitude-steered array for the purposes of imaging. The array is 10 cm in diameter and is operated in the frequency range of 80 to 304 kHz. Although the array is small for high-resolution imaging at these frequencies, the rungs of the ladder are recognizable in the images. The three pipes are difficult to discern in two of the projection images; however, the pipes separated in range are clear in the image showing vertical position versus range. The imaging concept is demonstrated on measured data, and the simulations agree well with the experimental results.

  19. 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). PMID:11865992

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

    PubMed

    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

  2. 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

  3. Hybrid image processing; Proceedings of the Meeting, Orlando, FL, Apr. 1, 2, 1986

    SciTech Connect

    Casasent, D.P.; Tescher, A.

    1986-01-01

    The conference presents papers on optical pattern recognition; optical image processing, artificial intelligence, and synthetic discrimination functions; digital image processing; and hybrid image processing. Attention is given to multiple optical filter design simulation results, acoustooptic image correlators, texture classification using the Hough transform, iteratively designed optical correlation filters for distortion invariant recognition, and an instrument-induced spatial crosstalk deconvolution algorithm. Papers are also presented on infrared power spectral density diurnal variations and clutter rejection scaling laws for focal plane arrays, the use of complementary analog and digital processing in the removal of local background in low contrast images, and the construction of low noise correlation filters.

  4. 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.

  5. A hybrid method for image interpolation

    NASA Astrophysics Data System (ADS)

    Qi, Chun; Huang, Hua; Wang, Wen-Bing; Zhang, Jing; Di, Shuangliang

    2003-09-01

    A hybrid method for image interpolation is proposed. The method consists of three different approaches: Circular arc or B-spline interpolation, linear interpolatino and human visual sensitivity based on interpolation. The image can be divided into three regions: linear smooth region, sharp edge region and human visual insensitive region. The method uses local variance and mean value to find different regions adaptively. The linear interpolation is used for linear smooth region. The human visual sensitivity based interpolation is used for human visual insensitive region and the circular arc or B-spline interpolation is used for sharp edge region. Experiments show that proposed method produces results that are more visually realistic than standard function-fitting methods.

  6. Image-like illumination with LED arrays: design.

    PubMed

    Moreno, Ivan

    2012-03-01

    An array of spatially distributed light-emitting diodes (LEDs) can produce an illumination pattern that approaches an image by individually modulating each LED. In this letter, I analyze the first-order design of such systems in order to achieve the best match between the illumination distribution and a desired image. In particular, simple formulas are given for the optimal number of LEDs, working distance, array size, and LED beam pattern. The analysis developed here may be applied to the design of LED systems such as architecture lighting, energy-efficient lighting, backlight local dimming for displays, and structured illumination microscopy with micro-LED arrays. PMID:22378411

  7. Transceiver array development for submillimeter-wave imaging radars

    NASA Astrophysics Data System (ADS)

    Cooper, Ken B.; Reck, Theodore A.; Jung-Kubiak, Cecile; Lee, Choonsup; Siles, Jose V.; Lin, Robert H.; Peralta, Alejandro; Decrossas, Emmanuel; Schlecht, Erich T.; Chattopadhyay, Goutam; Mehdi, Imran

    2013-05-01

    The Jet Propulsion Laboratory (JPL) is developing compact transceiver arrays housing discrete GaAs Schottky diodes with integrated waveguides in order to increase the frame rate and lower the cost of active submillimeter-wave imaging radar systems. As part of this effort, high performance diode frequency multiplier and mixer devices optimized for a 30 GHz bandwidth centered near 340 GHz have been fabricated using JPL's MoMeD process. A two-element array unit cell was designed using a layered architecture with three-dimensional waveguide routing for maximum scalability to multiple array elements. Prototype two-element arrays have been built using both conventionally machined metal blocks as well as gold-plated micromachined silicon substrates. Preliminary performance characterization has been accomplished in terms of transmit power, and conversion loss, and promising 3D radar images of concealed weapons have been acquired using the array.

  8. A doublet microlens array for imaging micron-sized objects

    PubMed Central

    Tripathi, A; Chronis, N

    2011-01-01

    We present a high-numerical aperture, doublet microlens array for imaging micron-sized objects. The proposed doublet architecture consists of glass microspheres trapped on a predefined array of silicon microholes and covered with a thin polymer layer. A standard silicon microfabrication process and a novel fluidic assembly technique were combined to obtain an array of 56 μm diameter microlenses with a numerical aperture of ~0.5. Using such an array, we demonstrated brightfield and fluorescent image formation of objects directly on a CCD sensor without the use of intermediate lenses. The proposed technology is a significant advancement toward the unmet need of inexpensive, miniaturized optical modules which can be further integrated with lab-on-chip microfluidic devices and photonic chips for a variety of high-end imaging/detection applications. PMID:22003271

  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. 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.

  11. Phased array antenna analysis using hybrid finite element methods

    NASA Astrophysics Data System (ADS)

    McGrath, Daniel T.

    1993-06-01

    This research in computational electromagnetics developed a new method for predicting the near-field mutual coupling effects in phased array antennas, using the finite element method (FEM) in combination with integral equations. Accurate feed modeling is accomplished by enforcing continuity between the FEM solution and an arbitrary number of wave guide models across a ground plane aperture. A periodic integral equation is imposed above the antenna's physical structure in order to enforce the radiation condition and to confine the analysis to an array unit cell. The electric field is expanded in terms of vector finite elements, and Galerkin's method is used to write the problem as a matrix equation. A general-purpose computer code was developed and validated by comparing its results to published data for several array types. Its versatility was demonstrated with predictions of the scanning properties of arrays of printed dipoles and printed flared notches.

  12. Flexible transceiver array for ultrahigh field human MR imaging.

    PubMed

    Wu, Bing; Zhang, Xiaoliang; Wang, Chunsheng; Li, Ye; Pang, Yong; Lu, Jonathan; Xu, Duan; Majumdar, Sharmila; Nelson, Sarah J; Vigneron, Daniel B

    2012-10-01

    A flexible transceiver array, capable of multiple-purpose imaging applications in vivo at ultrahigh magnetic fields was designed, implemented and tested on a 7 T MR scanner. By alternately placing coil elements with primary and secondary harmonics, improved decoupling among coil elements was accomplished without requiring decoupling circuitry between resonant elements, which is commonly required in high-frequency transceiver arrays to achieve sufficient element-isolation during radiofrequency excitation. This flexible array design is capable of maintaining the required decoupling among resonant elements in different array size and geometry and is scalable in coil size and number of resonant elements (i.e., number of channels), yielding improved filling factors for various body parts with different geometry and size. To investigate design feasibility, flexibility, and array performance, a multichannel, 16-element transceiver array was designed and constructed, and in vivo images of the human head, knee, and hand were acquired using a whole-body 7 T MR system. Seven Tesla parallel imaging with generalized autocalibrating partially parallel acquisitions (GRAPPA) performed using this flexible transceiver array was also presented. PMID:22246803

  13. 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. PMID:26907891

  14. 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.

  15. 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.

  16. 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

  17. 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.

  18. A hybrid continuous-wave terahertz imaging system.

    PubMed

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

    2015-11-01

    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. PMID:26628141

  19. A hybrid continuous-wave terahertz imaging system

    NASA Astrophysics Data System (ADS)

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

    2015-11-01

    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.

  20. Application of Array-Based Comparative Genomic Hybridization to Pediatric Neurologic Diseases

    PubMed Central

    Byeon, Jung Hye; Shin, Eunsim; Kim, Gun-Ha; Lee, Kyungok; Hong, Young Sook; Lee, Joo Won

    2014-01-01

    Purpose Array comparative genomic hybridization (array-CGH) is a technique used to analyze quantitative increase or decrease of chromosomes by competitive DNA hybridization of patients and controls. This study aimed to evaluate the benefits and yield of array-CGH in comparison with conventional karyotyping in pediatric neurology patients. Materials and Methods We included 87 patients from the pediatric neurology clinic with at least one of the following features: developmental delay, mental retardation, dysmorphic face, or epilepsy. DNA extracted from patients and controls was hybridized on the Roche NimbleGen 135K oligonucleotide array and compared with G-band karyotyping. The results were analyzed with findings reported in recent publications and internet databases. Results Chromosome imbalances, including 9 cases detected also by G-band karyotyping, were found in 28 patients (32.2%), and at least 19 of them seemed to be causally related to the abnormal phenotypes. Regarding each clinical symptom, 26.2% of 42 developmental delay patients, 44.4% of 18 mental retardation patients, 42.9% of 28 dysmorphic face patients, and 34.6% of 26 epilepsy patients showed abnormal array results. Conclusion Although there were relatively small number of tests in patients with pediatric neurologic disease, this study demonstrated that array-CGH is a very useful tool for clinical diagnosis of unknown genome abnormalities performed in pediatric neurology clinics. PMID:24339284

  1. 3D electrical tomographic imaging using vertical arrays of electrodes

    NASA Astrophysics Data System (ADS)

    Murphy, S. C.; Stanley, S. J.; Rhodes, D.; York, T. A.

    2006-11-01

    Linear arrays of electrodes in conjunction with electrical impedance tomography have been used to spatially interrogate industrial processes that have only limited access for sensor placement. This paper explores the compromises that are to be expected when using a small number of vertically positioned linear arrays to facilitate 3D imaging using electrical tomography. A configuration with three arrays is found to give reasonable results when compared with a 'conventional' arrangement of circumferential electrodes. A single array yields highly localized sensitivity that struggles to image the whole space. Strategies have been tested on a small-scale version of a sludge settling application that is of relevance to the industrial sponsor. A new electrode excitation strategy, referred to here as 'planar cross drive', is found to give superior results to an extended version of the adjacent electrodes technique due to the improved uniformity of the sensitivity across the domain. Recommendations are suggested for parameters to inform the scale-up to industrial vessels.

  2. Removing image artefacts in wire array metamaterials.

    PubMed

    Habib, Md Samiul; Tuniz, Alessandro; Kaltenecker, Korbinian J; Chateiller, Quentin; Perrin, Isadora; Atakaramians, Shaghik; Fleming, Simon C; Argyros, Alexander; Kuhlmey, Boris T

    2016-08-01

    Hyperlenses and hyperbolic media endoscopes can overcome the diffraction limit by supporting propagating high spatial frequency extraordinary waves. While hyperlenses can resolve subwavelength details far below the diffraction limit, images obtained from them are not perfect: resonant high spatial frequency slab modes as well as diffracting ordinary waves cause image distortion and artefacts. In order to use hyperlenses as broad-band subwavelength imaging devices, it is thus necessary to avoid or correct such unwanted artefacts. Here we introduce three methods, namely convolution, field averaging, and power averaging, to remove imaging artefacts over wide frequency bands, and numerically demonstrate their effectiveness based on simulations of a wire medium endoscope. We also define a projection in spatial Fourier space to effectively filter out all ordinary waves, leading to considerable reduction in image distortion. These methods are outlined and demonstrated for simple and complex apertures. PMID:27505766

  3. Plastic retina: image enhancement using polymer grid triode arrays

    NASA Astrophysics Data System (ADS)

    Heeger, Alan J.; Heeger, David J.; Langan, John D.; Yang, Yang

    1996-02-01

    An array of polymer grid triodes (PGTs) connected through a common grid functions as a 'plastic retina' which provides local contrast gain control for image enhancement. This device, made from layers of conducting polymers, functions as an active resistive network that performs center-surround filtering. The PGT array with common grid is a continuous analog of the discrete approach of Mead, with a variety of fabrication advantages and with a significant saving of 'real estate' within the unit cell of each pixel.

  4. 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.

  5. 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.

  6. Astronomical imaging with infrared array detectors.

    PubMed

    Gatley, I; Depoy, D L; Fowler, A M

    1988-12-01

    History shows that progress in astronomy often stems directly from technological innovation and that each portion of the electromagnetic spectrum offers unique insights into the nature of the universe. Most recently, the widespread availability of infrared-sensitive two-dimensional array detectors has led to dramatic improvements in the capabilities of conventional ground-based observatories. The impact of this new technology on our understanding of a wide variety of phenomena is illustrated here by infrared pictures of star-forming regions, of nebulae produced by the late stages of stellar evolution, of the nucleus of our own galaxy(the Milky Way), and of activity in other galaxies. PMID:17817072

  7. Surface plasmon enhanced quantum transport in a hybrid metal nanoparticle array

    NASA Astrophysics Data System (ADS)

    Sun, Lin; Nan, Yali; Xu, Shang; Zhang, Sishi; Han, Min

    2014-07-01

    Hybrid Pd-Ag nanoparticle arrays composed of randomly distributed Pd nanoparticles in dense packing and a small number of dispersed Ag nanoparticles were fabricated with controlled coverage. Photo-enhanced conductance was observed in the nanoparticle arrays. Largest enhancement, which can be higher than 20 folds, was obtained with 450 nm light illumination. This wavelength was found to correlate with the surface plasmon resonance of the Ag nanoparticles. Electron transport measurements showed there were significant Coulomb blockade in the nanoparticle arrays and the blockade could be overcome with the surface plasmon enhanced local field of Ag nanoparticles induced by light illumination.

  8. 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

  9. 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.

  10. Focusing surface wave imaging with flexible 2D array

    NASA Astrophysics Data System (ADS)

    Zhou, Shiyuan; Fu, Junqiang; Li, Zhe; Xu, Chunguang; Xiao, Dingguo; Wang, Shaohan

    2016-04-01

    Curved surface is widely exist in key parts of energy and power equipment, such as, turbine blade cylinder block and so on. Cycling loading and harsh working condition of enable fatigue cracks appear on the surface. The crack should be found in time to avoid catastrophic damage to the equipment. A flexible 2D array transducer was developed. 2D Phased Array focusing method (2DPA), Mode-Spatial Double Phased focusing method (MSDPF) and the imaging method using the flexible 2D array probe are studied. Experiments using these focusing and imaging method are carried out. Surface crack image is obtained with both 2DPA and MSDPF focusing method. It have been proved that MSDPF can be more adaptable for curved surface and more calculate efficient than 2DPA.

  11. 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

  12. Arrayed imaging reflectometry for inexpensive and label-free protein arrays

    NASA Astrophysics Data System (ADS)

    Striemer, Christopher C.; Mace, Charles R.; Carter, Jared A.; Mehta, Sourabh D.; Miller, Benjamin L.

    2009-02-01

    Highly sensitive optical techniques, capable of detecting very small quantities of specific proteins in a label-free format, offer great promise for pathogen detection because they avoid the complexity, expense, and process time associated with the use of secondary reporter elements. Arrayed Imaging Reflectometry (AIR) is one of the simplest label-free methodologies, combining laser reflectance imaging of a thermally oxidized silicon chip with standard microarray printing technology to create a platform with the potential to identify and quantify 100's of target proteins in a matter of minutes. This technique exploits a reflectance zero condition that is formed when s-polarized light strikes the surface of a silicon wafer with a single-layer oxide coating. In the vicinity of this deep reflectance minimum, picometer-scale variations in film thickness (surface relief) can be imaged directly in a reflected laser signal imaged with a CCD camera. By directly arraying probe molecules onto this substrate, minute changes in the optical thickness of each spot, corresponding to binding of the target of interest, can be measured. Array size is limited only by the resolution of the imaging system and the array printer, enabling complex protein signatures, indicative of specific pathogens or disease states to be measured in a biosample. The cost-effectiveness of a low-complexity substrate and reader, combined with the short assay times associated with label-free detection make AIR a promising new technology for pathogen and toxic exposure assessment.

  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. Ultraviolet photodetectors and imaging arrays based on III-V nitride heterostructures

    NASA Astrophysics Data System (ADS)

    Brown, Jeffrey David

    2000-10-01

    The III-V nitride class of compound semiconductors has received much attention in the last decade. These materials have a wide, direct bandgap, making them a prime candidate for optoelectronic devices in the blue, green, and ultraviolet spectral regions. These materials exhibit impressive optical, electrical, and thermal properties, even though there are fundamental materials issues that are thus far unresolved. This work explores the application of III-V nitride semiconductors to optical detectors in the ultraviolet region of the electromagnetic spectrum. Metalorganic vapor phase epitaxy was used to synthesize thin film p-i-n photodiode structures on double side polished sapphire substrates; these films were characterized for optical, electrical and structural properties. The grown structures were designed to respond to a predetermined region of the UV spectrum when illuminated from the substrate side. These structures were fabricated into devices using generally accepted techniques for dry etching and p and n-contact metallizations. Test devices were characterized using tools developed by the author. These devices demonstrated as high as 80% quantum efficiency and extremely low dark currents; resulting in spectral detectivities as large as 6 * 1013 cmHz1/2W-1. Devices were designed and demonstrated for a series of detection regions ranging from 365 nm to 250 nm. Photolithography masks were designed to allow the fabrication of photodiode arrays that would hybridize to commercially available CMOS based readout integrated circuits (ROICs), used routinely for infrared photodiode imaging. Photodiode arrays were fabricated and indium bumps were deposited onto the diode contacts and the ROICs to provide electrical connection. The hybrid detector arrays were placed in leadless chip carriers, wirebonded, and connected to commercially available drive and readout circuitry. Images of UV scenes were focused onto the arrays using fused quartz lenses. These images and movies

  15. Graphene/carbon nanotube hybrid-based transparent 2D optical array.

    PubMed

    Kim, Un Jeong; Lee, Il Ha; Bae, Jung Jun; Lee, Sangjin; Han, Gang Hee; Chae, Seung Jin; Güneş, Fethullah; Choi, Jun Hee; Baik, Chan Wook; Kim, Sun Il; Kim, Jong Min; Lee, Young Hee

    2011-09-01

    Graphene/carbon nanotube (CNT) hybrid structures are fabricated for use as optical arrays. Vertically aligned CNTs are directly synthesized on a graphene/quartz substrate using plasma-enhanced chemical vapor deposition (PECVD). Graphene preserves the transparency and resistance during CNT growth. Highly aligned single-walled CNTs show a better performance for the diffraction intensity. PMID:21769950

  16. Modulation transfer function measurement technique for image sensor arrays

    NASA Astrophysics Data System (ADS)

    Jin, Hui; Jiang, Huilin; Zhang, XiaoHui

    2010-08-01

    A new technique is demonstrated for measurement of modulation transfer function (MTF) on image sensor arrays. Fourier analysis of a low frequency bar target pattern is used to extract MTF at odd harmonics of a target pattern frequency up to and beyond Nyquist. The technique is particularly useful for linear image arrays (either conventional linescan or time-delay- integration devices) where conventional slanted-edge technique is not always applicable. The technique is well suited to simple implementation and can provide live presentation of the MTF curve, which helps to ensure optimal alignment conditions are achieved. Detailed analysis of the technique and demonstration of experimental results are presented.

  17. Nonuniformity effects in a hybrid platinum silicide imaging device

    NASA Astrophysics Data System (ADS)

    Dereniak, Eustace L.; Perry, David L.

    1992-05-01

    The objective of this project was twofold. The first objective was to characterize the Hughes Aircraft Company CRC-365 platinum silicide imaging device in a starting infrared sensor system. The CRC-365 is a hybrid 256 x 256 IR focal plane array that operates in the 3-5 micrometer thermal infrared band. A complete sensor and computer interface were built for these tests, using, plans provided by the Rome Laboratory at Hanscom AFB. Testing of the device revealed largely satisfactory performance, with notable exception in the areas of temporal response, temporal noise, and electrical crosstalk. The second objective of this research was to advance the understanding of how detector nonuniformity effects reduce the performance of sensors of this type. Notable accomplishments in this area included a complete linear analysis of corrected thermal imaging in platinum silicide sensors, a nonlinear analysis of the CRC-365's expected performance, analysis of its actual performance when operated with nonuniformity correction, and the development of a new figure of merit. It was demonstrated that the CRC-365 is capable of maintaining background-noise-limited performance over at least a 40 K target temperature range, when operated with two-point nonuniformity correction.

  18. Progress report on the use of hybrid silicon pin diode arrays in high energy physics

    SciTech Connect

    Shapiro, S.L. ); Jernigan, J.G.; Arens, J.F. . Space Sciences Lab.)

    1990-05-01

    We report on the successful effort to develop hybrid PIN diode arrays and to demonstrate their potential as components of vertex detectors. Hybrid pixel arrays have been fabricated by the Hughes Aircraft Co. by bump-bonding readout chips developed by Hughes to an array of PIN diodes manufactured by Micron Semiconductor Inc. These hybrid pixel arrays were constructed in two configurations. One array format has 10 {times} 64 pixels, each 120 {mu}m square; and the other format has 256 {times} 156 pixels, each 30 {mu}m square. In both cases, the thickness of the PIN diode layer is 300 {mu}m. Measurements of detector performance show that excellent position resolution can be achieved by interpolation. By determining the centroid of the charge cloud which spreads charge into a number of neighboring pixels, a spatial resolution of a few microns has been attained. The noise has been measured to be about 300 electrons (rms) at room temperature, as expected from KTC and dark current considerations, yielding a signal-to-noise ratio of about 100 for minimum ionizing particles. 4 refs., 17 figs.

  19. 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.

  20. Hybrid PET/MR imaging: physics and technical considerations.

    PubMed

    Shah, Shetal N; Huang, Steve S

    2015-08-01

    In just over a decade, hybrid imaging with FDG PET/CT has become a standard bearer in the management of cancer patients. An exquisitely sensitive whole-body imaging modality, it combines the ability to detect subtle biologic changes with FDG PET and the anatomic information offered by CT scans. With advances in MR technology and advent of novel targeted PET radiotracers, hybrid PET/MRI is an evolutionary technique that is poised to revolutionize hybrid imaging. It offers unparalleled spatial resolution and functional multi-parametric data combined with biologic information in the non-invasive detection and characterization of diseases, without the deleterious effects of ionizing radiation. This article reviews the basic principles of FDG PET and MR imaging, discusses the salient technical developments of hybrid PET/MR systems, and provides an introduction to FDG PET/MR image acquisition. PMID:25985965

  1. 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.

  2. Interlaced linear array sampling technique for electromagnetic wave imaging

    SciTech Connect

    Sheen, David M; McMakin, Douglas L

    2009-06-16

    An arrangement of receivers and transmitters used in wideband holographic imaging using a reduced number of physical antenna elements compared to established techniques and systems. At least one of the receivers is configured to receive the reflected signal from three or more of transmitters, and at least one transmitter is configured to transmit a signal to an object, the reflection of which will be received by at least three receivers. The improved arrays are easily incorporated into existing microwave and millimeter wave holographic imaging equipment utilizing the existing mechanical features of this equipment, as well as the existing wideband holographic imaging algorithms and electronics for constructing images.

  3. Fourier Spectral Filter Array for Optimal Multispectral Imaging.

    PubMed

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

    2016-04-01

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

  4. Photoacoustic Imaging of Animals with an Annular Transducer Array

    NASA Astrophysics Data System (ADS)

    Yang, Di-Wu; Zhou, Zhi-Bin; Zeng, Lv-Ming; Zhou, Xin; Chen, Xing-Hui

    2014-07-01

    A photoacoustic system with an annular transducer array is presented for rapid, high-resolution photoacoustic tomography of animals. An eight-channel data acquisition system is applied to capture the photoacoustic signals by using multiplexing and the total time of data acquisition and transferring is within 3 s. A limited-view filtered back projection algorithm is used to reconstruct the photoacoustic images. Experiments are performed on a mouse head and a rabbit head and clear photoacoustic images are obtained. The experimental results demonstrate that this imaging system holds the potential for imaging the human brain.

  5. Development of Hybrid Sensor Arrays for Sensor Arrays for Simultaneous Measurement of Pressure and Shear Stress Distribution

    NASA Technical Reports Server (NTRS)

    2000-01-01

    This document reports on the progress in developing hybrid sensors for the simultaneous measurement of pressure and shear stress. The key feature for the success of the proposed hybrid sensor array is the ability to deposit Cu-Ni alloy with proper composition (55 - 45) on a silicon wafer to form a strain gage. This alloy strain gage replaces the normally used Si strain gages in MEMS, which are highly nonlinear and temperature dependent. The copper nickel, with proper composition (55 - 45), was successfully deposited on a silicon wafer with a few trials during this period of the project. Pictures of the Cu-Ni alloy strain gage and the x-ray spectra indicating the composition are shown. The planned tests are also reviewed.

  6. 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. PMID:26285181

  7. A hybrid pyramid multiprocessor system for image processing. Volumes I and II

    SciTech Connect

    Chen, Inching.

    1989-01-01

    Various multiprocessor architectures have been considered by many researchers to handle the high computational requirements of image processing and analysis application. However, many of these architectures are efficient only for a small class of image processing algorithms. In this research, a multiprocessor system has been proposed, designed and constructed taking into consideration various input-output and other characteristics of image processing applications. It is a hybrid pyramid with five 68020-68881 based processor nodes in the top two layers and sixteen DSP56001 based processor nodes in the third layer. The DSP (RISC) processor nodes at the bottom level are optimized for low-level image processing operations and the CISC (68020) processor nodes handle high-level tasks more efficiently. Experiments using the algorithms that have operations on neighborhoods of different sizes have shown consistent improvement in performance if the FIFO cache is enabled. Larger neighborhoods result in greater saving in time. Preliminary test indicate that the top five processor nodes can execute five times as fast as a single node for many image processing tasks. Finally, the versatile image I/O with the MMU has created a simpler programming environment, while facilitating various I/O structures. The OSU pyramid is a general-purpose image processing system, utilizing pyramidal architecture of hybrid processors, with additional hardware to retain the advantageous features of array processors, as well as to overcome some of the inherent deficiencies of pipeline processors and cellular arrays.

  8. 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.

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

    NASA Astrophysics Data System (ADS)

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

    2008-04-01

    In our effort to develop large format kilo-pixel arrays of transition edge sensors, we are working toward demonstrating electrical connectivity of a hybridized 32×40 element detector to a NIST multiplexer. The geometry of large-scale arrays that attempt to maintain a high filling factor does not allow for typical fan-out wiring, thus the detector array is hybridized directly to the readout multiplexer. The two parts are bonded together with 10 micron tall indium bumps, which complete the electrical path and also provide mechanical strength. The indium hybridization was developed and performed at the Goddard Space Flight Center and has been shown to withstand tensile loading up to 0.26 gram-force per indium bump. A cavity is deep etched behind each pixel prior to bonding, leaving only 30 micron support walls, which maintains a high filling fraction. Electrical continuity has been shown through the indium path in room temperature measurements. We report on the fabrication process used to hybridize the parts and the subsequent electrical performance.

  10. Array-based comparative genomic hybridization (array CGH) for rapid prenatal diagnosis of cytogenetic abnormalities

    Technology Transfer Automated Retrieval System (TEKTRAN)

    We have shown in a prospective validation study that an array CGH test was highly accurate for rapid detection of chromosomal aneuploidies and deletions or duplications on fetal DNA samples in a clinical prenatal diagnostic setting. Here we present our updated "post-validation phase" experience with...

  11. Vitis Phylogenomics: Hybridization Intensities from a SNP Array Outperform Genotype Calls

    PubMed Central

    Miller, Allison J.; Matasci, Naim; Schwaninger, Heidi; Aradhya, Mallikarjuna K.; Prins, Bernard; Zhong, Gan-Yuan; Simon, Charles; Buckler, Edward S.; Myles, Sean

    2013-01-01

    Understanding relationships among species is a fundamental goal of evolutionary biology. Single nucleotide polymorphisms (SNPs) identified through next generation sequencing and related technologies enable phylogeny reconstruction by providing unprecedented numbers of characters for analysis. One approach to SNP-based phylogeny reconstruction is to identify SNPs in a subset of individuals, and then to compile SNPs on an array that can be used to genotype additional samples at hundreds or thousands of sites simultaneously. Although powerful and efficient, this method is subject to ascertainment bias because applying variation discovered in a representative subset to a larger sample favors identification of SNPs with high minor allele frequencies and introduces bias against rare alleles. Here, we demonstrate that the use of hybridization intensity data, rather than genotype calls, reduces the effects of ascertainment bias. Whereas traditional SNP calls assess known variants based on diversity housed in the discovery panel, hybridization intensity data survey variation in the broader sample pool, regardless of whether those variants are present in the initial SNP discovery process. We apply SNP genotype and hybridization intensity data derived from the Vitis9kSNP array developed for grape to show the effects of ascertainment bias and to reconstruct evolutionary relationships among Vitis species. We demonstrate that phylogenies constructed using hybridization intensities suffer less from the distorting effects of ascertainment bias, and are thus more accurate than phylogenies based on genotype calls. Moreover, we reconstruct the phylogeny of the genus Vitis using hybridization data, show that North American subgenus Vitis species are monophyletic, and resolve several previously poorly known relationships among North American species. This study builds on earlier work that applied the Vitis9kSNP array to evolutionary questions within Vitis vinifera and has general

  12. 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.

  13. 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.

  14. High-speed imaging by use of a photoswitch array

    NASA Astrophysics Data System (ADS)

    Chen, Anshi; Zu, Jing

    1996-09-01

    A new technique for recording the shadow image of a moving projectile is presented. The technique is both simple to understand as well as efficient in image recording and processing. The key to the method is the way in which the photoswitch array produces two analog output corresponding to the positions of the upper edge and the lower edge of the projectile. The two outputs are converted into a digital data stream and acquired by a computer. A simple computation is applied to reconstruct the image. Analytical results for system transfer function and time response is evaluated and verified experimentally.

  15. 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.

  16. 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.

  17. Photon-counting detector arrays based on microchannel array plates. [for image enhancement

    NASA Technical Reports Server (NTRS)

    Timothy, J. G.

    1975-01-01

    The recent development of the channel electron multiplier (CEM) and its miniaturization into the microchannel array plate (MCP) offers the possibility of fully combining the advantages of the photographic and photoelectric detection systems. The MCP has an image-intensifying capability and the potential of being developed to yield signal outputs superior to those of conventional photomultipliers. In particular, the MCP has a photon-counting capability with a negligible dark-count rate. Furthermore, the MCP can operate stably and efficiently at extreme-ultraviolet and soft X-ray wavelengths in a windowless configuration or can be integrated with a photo-cathode in a sealed tube for use at ultraviolet and visible wavelengths. The operation of one- and two-dimensional photon-counting detector arrays based on the MCP at extreme-ultraviolet wavelengths is described, and the design of sealed arrays for use at ultraviolet and visible wavelengths is briefly discussed.

  18. Fully integrated hybrid silicon free-space beam steering source with 32-channel phased array

    NASA Astrophysics Data System (ADS)

    Hulme, J. C.; Doylend, J. K.; Heck, M. J. R.; Peters, J. D.; Davenport, M. L.; Bovington, J. T.; Coldren, L. A.; Bowers, J. E.

    2014-03-01

    Free-space beam steering using optical phased arrays is a promising method for implementing free-space communication links and Light Detection and Ranging (LIDAR) without the sensitivity to inertial forces and long latencies which characterize moving parts. Implementing this approach on a silicon-based photonic integrated circuit adds the additional advantage of working with highly developed CMOS processing techniques. In this work we discuss our progress in the development of a fully integrated 32 channel PIC with a widely tunable diode laser, a waveguide phased array, an array of fast phase modulators, an array of hybrid III-V/silicon amplifiers, surface gratings, and a graded index lens (GRIN) feeding an array of photodiodes for feedback control. The PIC has been designed to provide beam steering across a 15°x5° field of view with 0.6°x0.6° beam width and background peaks suppressed 15 dB relative to the main lobe within the field of view for arbitrarily chosen beam directions. Fabrication follows the hybrid silicon process developed at UCSB with modifications to incorporate silicon diodes and a GRIN lens.

  19. 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.

  20. NeuroSeek dual-color image processing infrared focal plane array

    NASA Astrophysics Data System (ADS)

    McCarley, Paul L.; Massie, Mark A.; Baxter, Christopher R.; Huynh, Buu L.

    1998-09-01

    Several technologies have been developed in recent years to advance the state of the art of IR sensor systems including dual color affordable focal planes, on-focal plane array biologically inspired image and signal processing techniques and spectral sensing techniques. Pacific Advanced Technology (PAT) and the Air Force Research Lab Munitions Directorate have developed a system which incorporates the best of these capabilities into a single device. The 'NeuroSeek' device integrates these technologies into an IR focal plane array (FPA) which combines multicolor Midwave IR/Longwave IR radiometric response with on-focal plane 'smart' neuromorphic analog image processing. The readout and processing integrated circuit very large scale integration chip which was developed under this effort will be hybridized to a dual color detector array to produce the NeuroSeek FPA, which will have the capability to fuse multiple pixel-based sensor inputs directly on the focal plane. Great advantages are afforded by application of massively parallel processing algorithms to image data in the analog domain; the high speed and low power consumption of this device mimic operations performed in the human retina.

  1. 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).

  2. High-frequency ultrasound annular-array imaging. Part I: array design and fabrication.

    PubMed

    Snook, Kevin A; Hu, Chang-Hong; Shrout, Thomas R; Shung, K Kirk

    2006-02-01

    This is Part I of a series of two papers describing the development of a digital high-frequency, annular-array, ultrasonic imaging system. In this paper, the design and fabrication of a high-frequency annular array as well as its performance will be reported. A six-element, 50 MHz array, which incorporated an acoustic lens to provide an initial focal point, was designed and fabricated. A submicron size grain lead titanate piezoelectric ceramic was used to both reduce lateral coupling and keep the electrical impedance matched close to the 50 ohm receive electronics. The array elements were isolated using laser micromachining to fully separate the annuli, and electrical interconnection was achieved by directly soldering thin wires to the elements. The resulting array attained an average impulse response that exhibited a 43 MHz center frequency, 30% relative bandwidth, and an average insertion loss of 31 dB at 45 MHz. Maximum next-element crosstalk was -27 dB in water. PMID:16529104

  3. High-resolution seismic array imaging based on numerical seismic wave simulations

    NASA Astrophysics Data System (ADS)

    Liu, Q.; Tong, P.; Chen, C.

    2012-12-01

    Adjoint tomography, i.e., seismic tomography based on full numerical simulations and adjoint methods, is a powerful tool for high-resolution imaging in heterogeneous media. It resolves large velocity contrasts through the use of 3D initial models and exploits more quantitative information from observed seismograms. However, for regions with limited local seismicity, seismic imaging relies more on teleseismic records. In particular coda and converted waves of main teleseismic arrivals used in scattering imaging are vital in resolving subsurface interfaces and velocity anomalies beneath seismic arrays. It remains numerically challenging to accurately and efficiently simulate the full propagation of seismic waves at the frequencies relevant to scattering imaging. In this work, to simulate the propagation of teleseismic planes waves into localized heterogeneous structures, we apply a hybrid method that interacts a spectral-element solver within the domain with a semi-analytical solution for 1D background medium at the absorbing boundaries. This technique will be implemented in both SPECFEM2D and SPECFEM3D packages and make it possible to invert both regional and teleseismic recordings in the framework of adjoint tomography. Synthetic tests will be performed to show the feasibility of high-resolution seismic array imaging of coda and converted waves based on adjoint techniques.

  4. 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.

  5. Measurement of the proton-air cross section with Telescope Array's Middle Drum detector and surface array in hybrid mode

    NASA Astrophysics Data System (ADS)

    Abbasi, R. U.; Abe, M.; Abu-Zayyad, T.; Allen, M.; Azuma, R.; Barcikowski, E.; Belz, J. W.; Bergman, D. R.; Blake, S. A.; Cady, R.; Chae, M. J.; Cheon, B. G.; Chiba, J.; Chikawa, M.; Cho, W. R.; Fujii, T.; Fukushima, M.; Goto, T.; Hanlon, W.; Hayashi, Y.; Hayashida, N.; Hibino, K.; Honda, K.; Ikeda, D.; Inoue, N.; Ishii, T.; Ishimori, R.; Ito, H.; Ivanov, D.; Jui, C. C. H.; Kadota, K.; Kakimoto, F.; Kalashev, O.; Kasahara, K.; Kawai, H.; Kawakami, S.; Kawana, S.; Kawata, K.; Kido, E.; Kim, H. B.; Kim, J. H.; Kim, J. H.; Kitamura, S.; Kitamura, Y.; Kuzmin, V.; Kwon, Y. J.; Lan, J.; Lim, S. I.; Lundquist, J. P.; Machida, K.; Martens, K.; Matsuda, T.; Matsuyama, T.; Matthews, J. N.; Minamino, M.; Mukai, Y.; Myers, I.; Nagasawa, K.; Nagataki, S.; Nakamura, T.; Nonaka, T.; Nozato, A.; Ogio, S.; Ogura, J.; Ohnishi, M.; Ohoka, H.; Oki, K.; Okuda, T.; Ono, M.; Oshima, A.; Ozawa, S.; Park, I. H.; Pshirkov, M. S.; Rodriguez, D. C.; Rubtsov, G.; Ryu, D.; Sagawa, H.; Sakurai, N.; Scott, L. M.; Shah, P. D.; Shibata, F.; Shibata, T.; Shimodaira, H.; Shin, B. K.; Shin, H. S.; Smith, J. D.; Sokolsky, P.; Springer, R. W.; Stokes, B. T.; Stratton, S. R.; Stroman, T. A.; Suzawa, T.; Takamura, M.; Takeda, M.; Takeishi, R.; Taketa, A.; Takita, M.; Tameda, Y.; Tanaka, H.; Tanaka, K.; Tanaka, M.; Thomas, S. B.; Thomson, G. B.; Tinyakov, P.; Tkachev, I.; Tokuno, H.; Tomida, T.; Troitsky, S.; Tsunesada, Y.; Tsutsumi, K.; Uchihori, Y.; Udo, S.; Urban, F.; Vasiloff, G.; Wong, T.; Yamane, R.; Yamaoka, H.; Yamazaki, K.; Yang, J.; Yashiro, K.; Yoneda, Y.; Yoshida, S.; Yoshii, H.; Zollinger, R.; Zundel, Z.; Telescope Array Collaboration

    2015-08-01

    In this work we are reporting on the measurement of the proton-air inelastic cross section σp-air inel using the Telescope Array detector. Based on the measurement of the σp-air inel, the proton-proton cross section σp -p value is also determined at √{s }=9 5-8+5 TeV . Detecting cosmic ray events at ultrahigh energies with the Telescope Array enables us to study this fundamental parameter that we are otherwise unable to access with particle accelerators. The data used in this report are the hybrid events observed by the Middle Drum fluorescence detector together with the surface array detector collected over five years. The value of the σp-air inel is found to be equal to 567.0 ±70.5 [Stat]-25+29[Sys] mb . The total proton-proton cross section is subsequently inferred from Glauber formalism and the Block, Halzen and Stanev QCD inspired fit and is found to be equal to 17 0-44+48[Stat]-17+19[Sys] mb .

  6. 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

  7. 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.

  8. Two-dimensional pixel array image sensor for protein crystallography

    SciTech Connect

    Beuville, E.; Beche, J.-F.; Cork, C.

    1996-07-01

    A 2D pixel array image sensor module has been designed for time resolved Protein Crystallography. This smart pixels detector significantly enhances time resolved Laue Protein crystallography by two to three orders of magnitude compared to existing sensors like films or phosphor screens coupled to CCDs. The resolution in time and dynamic range of this type of detector will allow one to study the evolution of structural changes that occur within the protein as a function of time. This detector will also considerably accelerate data collection in static Laue or monochromatic crystallography and make better use of the intense beam delivered by synchrotron light sources. The event driven pixel array detectors, based on the column Architecture, can provide multiparameter information (energy discrimination, time), with sparse and frameless readout without significant dead time. The prototype module consists of a 16x16 pixel diode array bump-bonded to the integrated circuit. The detection area is 150x150 square microns.

  9. Multianode microchannel array detectors for Space Shuttle imaging applications

    NASA Technical Reports Server (NTRS)

    Timothy, J. G.; Bybee, R. L.

    1981-01-01

    The Multi-Anode Microchannel Arrays (MAMAs) are a family of photoelectric, photoncounting array detectors that have been developed and qualified specifically for use in space. MAMA detectors with formats as large as 256 x 1024 pixels are now in use or under construction for a variety of imaging and tracking applications. These photo-emissive detectors can be operated in a windowless configuration at extreme ultraviolet and soft X-ray wavelengths or in a sealed configuration at ultraviolet and visible wavelengths. The construction and modes-of-operation of the MAMA detectors are briefly described and the scientific objectives of a number of sounding rocket and Space Shuttle instruments utilizing these detectors are outlined. Performance characteristics of the MAMA detectors that are of fundamental importance for operation in the Space Shuttle environment are described and compared with those of the photo-conductive array detectors such as the CCDs and CIDs.

  10. Nineteen-Channel Receive Array and Four-Channel Transmit Array Coil for Cervical Spinal Cord Imaging at 7T

    PubMed Central

    Zhao, Wei; Cohen-Adad, Julien; Polimeni, Jonathan R.; Keil, Boris; Guerin, Bastien; Setsompop, Kawin; Serano, Peter; Mareyam, Azma; Hoecht, Philipp; Wald, Lawrence L.

    2016-01-01

    Purpose To design and validate a radiofrequency (RF) array coil for cervical spinal cord imaging at 7T. Methods A 19-channel receive array with a four-channel transmit array was developed on a close-fitting coil former at 7T. Transmit efficiency and specific absorption rate were evaluated in a B1+ mapping study and an electromagnetic model. Receive signal-to-noise ratio (SNR) and noise amplification for parallel imaging were evaluated and compared with a commercial 3T 19-channel head–neck array and a 7T four-channel spine array. The performance of the array was qualitatively demonstrated in human volunteers using high-resolution imaging (down to 300 μm in-plane). Results The transmit and receive arrays showed good bench performance. The SNR was approximately 4.2-fold higher in the 7T receive array at the location of the cord with respect to the 3T coil. The g-factor results showed an additional acceleration was possible with the 7T array. In vivo imaging was feasible and showed high SNR and tissue contrast. Conclusion The highly parallel transmit and receive arrays were demonstrated to be fit for spinal cord imaging at 7T. The high sensitivity of the receive coil combined with ultra-high field will likely improve investigations of microstructure and tissue segmentation in the healthy and pathological spinal cord. PMID:23963998

  11. Application of Array Comparative Genomic Hybridization in Newborns with Multiple Congenital Anomalies.

    PubMed

    Szczałuba, Krzysztof; Nowakowska, Beata; Sobecka, Katarzyna; Smyk, Marta; Castaneda, Jennifer; Klapecki, Jakub; Kutkowska-Kaźmierczak, Anna; Śmigiel, Robert; Bocian, Ewa; Radkowski, Marek; Demkow, Urszula

    2016-01-01

    Major congenital anomalies are detectable in 2-3 % of the newborn population. Some of their genetic causes are attributable to copy number variations identified by array comparative genomic hybridization (aCGH). The value of aCGH screening as a first-tier test in children with multiple congenital anomalies has been studied and consensus adopted. However, array resolution has not been agreed upon, specifically in the newborn or infant population. Moreover, most array studies have been focused on mixed populations of intellectual disability/developmental delay with or without multiple congenital anomalies, making it difficult to assess the value of microarrays in newborns. The aim of the study was to determine the optimal quality and clinical sensitivity of high-resolution array comparative genomic hybridization in neonates with multiple congenital anomalies. We investigated a group of 54 newborns with multiple congenital anomalies defined as two or more birth defects from more than one organ system. Cytogenetic studies were performed using OGT CytoSure 8 × 60 K microarray. We found ten rearrangements in ten newborns. Of these, one recurrent syndromic microduplication was observed, whereas all other changes were unique. Six rearrangements were definitely pathogenic, including one submicroscopic and five that could be seen on routine karyotype analysis. Four other copy number variants were likely pathogenic. The candidate genes that may explain the phenotype were discussed. In conclusion, high-resolution array comparative hybridization can be applied successfully in newborns with multiple congenital anomalies as the method detects a significant number of pathogenic changes, resulting in early diagnoses. We hypothesize that small changes previously considered benign or even inherited rearrangements should be classified as potentially pathogenic at least until a subsequent clinical assessment would exclude a developmental delay or dysmorphism. PMID:26987320

  12. VERITAS: the Very Energetic Radiation Imaging Telescope Array System

    NASA Astrophysics Data System (ADS)

    Weekes, T. C.; Badran, H.; Biller, S. D.; Bond, I.; Bradbury, S.; Buckley, J.; Carter-Lewis, D.; Catanese, M.; Criswell, S.; Cui, W.; Dowkontt, P.; Duke, C.; Fegan, D. J.; Finley, J.; Fortson, L.; Gaidos, J.; Gillanders, G. H.; Grindlay, J.; Hall, T. A.; Harris, K.; Hillas, A. M.; Kaaret, P.; Kertzman, M.; Kieda, D.; Krennrich, F.; Lang, M. J.; LeBohec, S.; Lessard, R.; Lloyd-Evans, J.; Knapp, J.; McKernan, B.; McEnery, J.; Moriarty, P.; Muller, D.; Ogden, P.; Ong, R.; Petry, D.; Quinn, J.; Reay, N. W.; Reynolds, P. T.; Rose, J.; Salamon, M.; Sembroski, G.; Sidwell, R.; Slane, P.; Stanton, N.; Swordy, S. P.; Vassiliev, V. V.; Wakely, S. P.

    2002-05-01

    The Very Energetic Radiation Imaging Telescope Array System (VERITAS) represents an important step forward in the study of extreme astrophysical processes in the universe. It combines the power of the atmospheric Cherenkov imaging technique using a large optical reflector with the power of stereoscopic observatories using arrays of separated telescopes looking at the same shower. The seven identical telescopes in VERITAS, each of aperture 10 m, will be deployed in a filled hexagonal pattern of side 80 m; each telescope will have a camera consisting of 499 pixels with a field of view of 3.5°. VERITAS will substantially increase the catalog of very high energy ( E>100 GeV) γ-ray sources and greatly improve measurements of established sources.

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

    PubMed

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

    2016-09-01

    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. PMID:27607698

  14. 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

  15. 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.

  16. 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.

  17. Fabrication of large-area arrays of hybrid nanostructures on polymer-derived chemically patterned surfaces

    NASA Astrophysics Data System (ADS)

    Liu, Xiaoying; Nepal, Dhriti; Biswas, Sushmita; Park, Kyoungweon; Vaia, Richard; Nealey, Paul; Air Force Research Laboratories Collaboration; University of Chicago Team

    2014-03-01

    The precise placement and assembly of nanoparticles (NPs) into large-area nanostructure arrays will allow for the design and implementation of advanced nanoscale devices for applications in fields such as quantum computing, optical sensing, superlenses, photocatalysis, photovoltaics, and non-linear optics. Our work is focused on using chemically nanopatterned surfaces to fabricate arrays of hybrid nanostructures with each component of the building block at well-defined positions. The precise chemical contrast patterns with densities and resolution of features created using standard tools of lithography, polymer self-assembly, and surface functionalization allow for control of position and interparticle spacing through selective surface-particle and particle-particle interactions. We have demonstrated the assembly of NPs, including metallic NPs and semiconductor quantum dots, into arrays of hybrid structures with various geometries, such as monomers, dimers, quatrefoils, stripes, and chains. We have developed protocols to fabricate NP arrays over a variety of substrates, which allows for the design and characterization of optical and electronic nanostructures and devices to meet the requirements of various technological applications.

  18. 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. PMID:26922719

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

    NASA Astrophysics Data System (ADS)

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

    2014-02-01

    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.

  20. 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.

  1. Hexagonal uniformly redundant arrays for coded-aperture imaging

    NASA Technical Reports Server (NTRS)

    Finger, M. H.; Prince, T. A.

    1985-01-01

    Uniformly redundant arrays are used in coded-aperture imaging, a technique for forming images without mirrors or lenses. The URAs constructed on hexagonal lattices, are outlined. Details are presented for the construction of a special class of URAs, the skew-Hadamard URAs, which have the following properties: (1) nearly half open and half closed (2) antisymmetric upon rotation by 180 deg except for the central cell and its repetitions. Some of the skew-Hadamard URAs constructed on a hexagonal lattice have additional symmetries. These special URAs that have a hexagonal unit pattern, and are antisymmetric upon rotation by 60 deg, called hexagonal uniformly redundant arrays (HURAs). The HURAs are particularly suited to gamma-ray imaging in high background situations. In a high background situation the best sensitivity is obtained with a half open and half closed mask. The hexagonal symmetry of an HURA is more appropriate for a round position-sensitive detector or a closed-packed array of detectors than a rectangular symmetry.

  2. 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.

  3. Development of a Magnetic Nanoparticle Susceptibility Magnitude Imaging Array

    PubMed Central

    Ficko, Bradley W.; Nadar, Priyanka M.; Hoopes, P. Jack; Diamond, Solomon G.

    2014-01-01

    There are several emerging diagnostic and therapeutic applications of magnetic nanoparticles (mNPs) in medicine. This study examines the potential for developing an mNP imager that meets these emerging clinical needs with a low cost imaging solution that uses arrays of digitally controlled drive coils in a multiple-frequency, continuous-wave operating mode and compensated fluxgate magnetometers. The design approach is described and a mathematical model is developed to support measurement and imaging. A prototype is used to demonstrate active compensation of up to 185 times the primary applied magnetic field, depth sensitivity up to 2.5 cm (p < 0.01), and linearity over 5 dilutions (R2 > 0.98, p <0.001). System frequency responses show distinguishable readouts for iron oxide mNPs with single magnetic domain core diameters of 10 nm and 40 nm, and multi-domain mNPs with a hydrodynamic diameter of 100 nm. Tomographic images show a contrast-to-noise ratio of 23 for 0.5 ml of 12.5 mg Fe/ml mNPs at 1 cm depth. A demonstration involving the injection of mNPs into pork sausage shows the potential for use in biological systems. These results indicate that the proposed mNP imaging approach can potentially be extended to a larger array system with higher-resolution. PMID:24504184

  4. Development of a magnetic nanoparticle susceptibility magnitude imaging array.

    PubMed

    Ficko, Bradley W; Nadar, Priyanka M; Hoopes, P Jack; Diamond, Solomon G

    2014-02-21

    There are several emerging diagnostic and therapeutic applications of magnetic nanoparticles (mNPs) in medicine. This study examines the potential for developing an mNP imager that meets these emerging clinical needs with a low cost imaging solution that uses arrays of digitally controlled drive coils in a multiple-frequency, continuous-wave operating mode and compensated fluxgate magnetometers. The design approach is described and a mathematical model is developed to support measurement and imaging. A prototype is used to demonstrate active compensation of up to 185 times the primary applied magnetic field, depth sensitivity up to 2.5 cm (p < 0.01), and linearity over five dilutions (R(2) > 0.98, p < 0.001). System frequency responses show distinguishable readouts for iron oxide mNPs with single magnetic domain core diameters of 10 and 40 nm, and multi-domain mNPs with a hydrodynamic diameter of 100 nm. Tomographic images show a contrast-to-noise ratio of 23 for 0.5 ml of 12.5 mg Fe ml(-1) mNPs at 1 cm depth. A demonstration involving the injection of mNPs into pork sausage shows the potential for use in biological systems. These results indicate that the proposed mNP imaging approach can potentially be extended to a larger array system with higher-resolution. PMID:24504184

  5. Development of a magnetic nanoparticle susceptibility magnitude imaging array

    NASA Astrophysics Data System (ADS)

    Ficko, Bradley W.; Nadar, Priyanka M.; Hoopes, P. Jack; Diamond, Solomon G.

    2014-02-01

    There are several emerging diagnostic and therapeutic applications of magnetic nanoparticles (mNPs) in medicine. This study examines the potential for developing an mNP imager that meets these emerging clinical needs with a low cost imaging solution that uses arrays of digitally controlled drive coils in a multiple-frequency, continuous-wave operating mode and compensated fluxgate magnetometers. The design approach is described and a mathematical model is developed to support measurement and imaging. A prototype is used to demonstrate active compensation of up to 185 times the primary applied magnetic field, depth sensitivity up to 2.5 cm (p < 0.01), and linearity over five dilutions (R2 > 0.98, p < 0.001). System frequency responses show distinguishable readouts for iron oxide mNPs with single magnetic domain core diameters of 10 and 40 nm, and multi-domain mNPs with a hydrodynamic diameter of 100 nm. Tomographic images show a contrast-to-noise ratio of 23 for 0.5 ml of 12.5 mg Fe ml-1 mNPs at 1 cm depth. A demonstration involving the injection of mNPs into pork sausage shows the potential for use in biological systems. These results indicate that the proposed mNP imaging approach can potentially be extended to a larger array system with higher-resolution.

  6. Imaging Ferromagnetic Tracers with a Magnetoresistive Sensors Array

    NASA Astrophysics Data System (ADS)

    Leyva, Juan A.; Carneiro, Antonio A. O.; Murta, Luís O.; Baffa, O.

    2006-09-01

    The aim of this work was to study the feasibility to obtain images from a distribution of ferromagnetic tracers using a magnetoresistive multichannel sensor array (MRA). A magnetic imaging system formed by a linear array composed of 12 magnetoresistive sensors (Honeywell HMC 1001) was constructed covering a scanning area of (16×18) cm2. The signal was pre-processed for off-set correction and interpolation to generate a matrix of (256×256). The point spread function of the MRA was evaluated and the sensors were spaced accordingly. The magnetic images were generated by mapping the response of the MRA at short distances from the presence of a magnetite powder dispersed in planar phantoms with different shapes. The phantoms were magnetized by a pulse field of approximately 80 mT produced by a Helmholtz coil. Using the Wiener filtering, the magnetic source images were obtained. We conclude that this biomagnetic method can be successfully used to generate planar functional images of the gastrointestinal tract using magnetic markers in the near field.

  7. 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

  8. Advanced numerical modeling and hybridization techniques for third-generation infrared detector pixel arrays

    NASA Astrophysics Data System (ADS)

    Schuster, Jonathan

    to their final hybridization onto expensive silicon read-out integrated circuit (ROIC) chips. The approach is to temporarily hybridize each candidate HgCdTe detector array to a standard reusable ROIC for complete screen testing. We tested the technique by temporarily hybridizing LPE grown HgCdTe test chips to fan-out boards and characterizing their performance.

  9. Control of satellite imaging arrays in multi-body regimes

    NASA Astrophysics Data System (ADS)

    Millard, Lindsay Demoore

    In the current study, control strategies are investigated for spacecraft imaging formations in multi-body regimes. The specific focus of the analysis is spacecraft motion as modeled in the circular restricted three-body problem, where two large gravitational bodies affect the motion of spacecraft in their vicinity. Five equilibrium points, or libration points, exist as solutions to the differential equations of motion in the circular restricted three-body problem. A specific periodic solution to these equations is an orbit in the vicinity of a libration point, i.e., a halo orbit. Halo orbits are ideal locations for spacecraft imaging arrays as they remain at a nearly fixed distance from the larger, or primary, bodies in the system. For example, if the Sun and Earth are considered the primary bodies, a spacecraft array can be placed near a libration point on the far side of the Earth, protected from the harsh radiation of the Sun at all times. A model of image reconstruction is developed for two common satellite imaging platform designs: an interferometric sparse aperture array and an occulter-telescope formation. The resolution of an image produced by an array is largely determined by the corresponding coverage of the (u, v) plane. The (u, v) plane is not a physical plane, but rather a relationship between frequencies and amplitudes in the Fourier expansion of the electromagnetic signal from the object of interest. Coverage of the (u, v) plane is derived based on several characteristics of the spacecraft configuration and the motion in physical space. Therefore, to determine formation motion history that may be advantageous to imaging, a mathematical model relating spacecraft motion in physical space to coverage of the (u, v) plane, and thus image reconstruction, is necessary. From these models, two control algorithms are developed that increase the resolution of the images produced by the formation while exploiting multi-body dynamics to reduce satellite fuel

  10. Evaluation of the Teledyne SIDECAR ASIC at cryogenic temperature using a visible hybrid H2RG focal plane array in 32 channel readout mode

    NASA Astrophysics Data System (ADS)

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

    2008-07-01

    Teledyne Imaging Sensors (TIS) has developed a new CMOS device known as the SIDECAR application-specific integrated circuit (ASIC). This single chip provides all the functionality of FPA drive electronics to operate visible and infrared imaging detectors with a fully digital interface. At the last SPIE conference we presented test and performance results of a Teledyne 2K×2K silicon PIN diode array hybridized to a Hawaii-2RG multiplexer, the Hybrid Visible Silicon Imager (HyViSI). This detector was read out with the ESO standard IR detector controller IRACE, which delivers detector limited performance. We have now tested the H2RG HyViSI detector with the new TIS SIDECAR ASIC in 32 channel readout mode at cryogenic temperatures. The SIDECAR has been evaluated down to 105 Kelvin operating temperature and performance results have been compared to those obtained with external electronics. We find that the SIDECAR ASIC provides performance equal to optimized external electronics.

  11. 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.

  12. 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

  13. Fabrication and characterization of a hybrid SOI 1×4 silicon-slot optical modulator array incorporating EO polymers for optical phased-array antenna applications

    NASA Astrophysics Data System (ADS)

    Kim, Richard S.; Szep, Attila; Usechak, Nicholas G.; Chen, Antao; Sun, Haishan; Shi, Shouyuan; Abeysinghe, Don; You, Young-Hwan; Dalton, Larry R.

    2012-03-01

    Optical phased arrays are promising candidates for both RF signal processing and optical beam forming and steering. These platforms not only enable accurate electrically controlled beam steering at high frequencies but also have the potential to significantly improve the performance of future free-space optical communications systems. In this work we exploit recent advancements in both nano-scale hybrid silicon-slot waveguides and electro-optic (EO) polymers to demonstrate an integrated optical phased-array antenna. Specifically, we create a hybrid integrated "photonic circuit" that connects an array of optical phase modulators, fed by a common optical signal and a 1x4 splitter, to a compact optical waveguide diffraction array for optical beam steering applications. The fundamental characteristics of the resulting integrated optical beam former, including the optical insertion loss, driving voltage, and phase control from the waveguide aperture are summarized in this letter.

  14. A 94 GHz imaging array using slot line radiators

    NASA Astrophysics Data System (ADS)

    Korzeniowski, T. L.

    1985-09-01

    A planar endfire slotted-line antenna structure was investigated. It was found that the H-plane beamwidths are basically dependent upon the substrate properties, whereas the E-plane beamwidths are more strongly a function of the slot's shape and size. It is shown that these antennas produce symmetrical E and H-plane beamwidths while following Zucker's standard traveling-wave antenna beamwidth curves over some range of antenna normalized length. An empircally derived design formula for effective substrate thickness is shown to predict this range for linearly tapered slotted-line antennas. The experimental imaging properties of these arrays are presented and imaging theory is discussed. It is shown that a minimum spacing of elements is necessary for exact reconstruction for a sampled image in a diffraction limited system. Because these LTSA elements employ the traveling-wave mechanism of radiation, they can be spaced two times closer than a conical feed horn of comparable beamwidth.

  15. Stochastic Resonance Magnetic Force Microscopy imaging of Josephson Arrays

    NASA Astrophysics Data System (ADS)

    Naibert, Tyler; Polshyn, Hryhoriy; Wolin, Brian; Durkin, Malcolm; Garrido Menacho, Rita; Mondragon Shem, Ian; Chua, Victor; Hughes, Taylor; Mason, Nadya; Budakian, Raffi

    Vortex interactions are key to explaining the behavior of many two dimensional superconducting systems. We report on the development of a technique to locally probe vortex interactions in a 2D array of Josephson junctions. Scanning a magnetic tip attached to an ultra-soft cantilever over the array produces changes in the frequency of the cantilever along certain lines, forming geometric patterns in the scans. Different tip-surface separations and external magnetic fields produce a number of different patterns. These patterns correspond to tip locations in which two configurations of vortices in the lattice have degenerate energies. By imaging the locations of these degeneracies, information on the local vortex interactions may be obtained.

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

    PubMed

    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

    2015-08-01

    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. PMID:26136109

  17. Characterization of orthogonal transfer array CCDs for the WIYN one degree imager

    NASA Astrophysics Data System (ADS)

    Lesser, Michael; Ouellette, David; Boroson, Todd; Harbeck, Daniel; Martin, Pierre; Jacoby, George; Cavin, John; Sawyer, David; Boggs, Kasey; Bredthauer, Richard

    2012-03-01

    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 consists of an 8x8 grid of Orthogonal Transfer Array (OTA) CCD detectors. These detectors are the STA2200 OTA CCDs designed and fabricated by Semiconductor Technology Associates, Inc. and backside processed at the University of Arizona Imaging Technology Laboratory. Several lot runs of the STA2200 detectors have been fabricated. We have backside processed devices from these different lots and provide detector performance characterization, including noise, CTE, cosmetics, quantum efficiency, and some orthogonal transfer characteristics. We discuss the performance differences for the devices with different silicon thickness and resistivity. A fully buttable custom detector package has been developed for this project which allows hybridization of the silicon detectors directly onto an aluminum nitride substrate with an embedded pin grid array. This package is mounted on a silicon-aluminum alloy which provides a flat imaging surface of less than 20 microns peakvalley at the -100 C operating temperature. Characterization of the package performance, including low temperature profilometry, is described in this paper.

  18. Hybrid segmentation framework for 3D medical image analysis

    NASA Astrophysics Data System (ADS)

    Chen, Ting; Metaxas, Dimitri N.

    2003-05-01

    Medical image segmentation is the process that defines the region of interest in the image volume. Classical segmentation methods such as region-based methods and boundary-based methods cannot make full use of the information provided by the image. In this paper we proposed a general hybrid framework for 3D medical image segmentation purposes. In our approach we combine the Gibbs Prior model, and the deformable model. First, Gibbs Prior models are applied onto each slice in a 3D medical image volume and the segmentation results are combined to a 3D binary masks of the object. Then we create a deformable mesh based on this 3D binary mask. The deformable model will be lead to the edge features in the volume with the help of image derived external forces. The deformable model segmentation result can be used to update the parameters for Gibbs Prior models. These methods will then work recursively to reach a global segmentation solution. The hybrid segmentation framework has been applied to images with the objective of lung, heart, colon, jaw, tumor, and brain. The experimental data includes MRI (T1, T2, PD), CT, X-ray, Ultra-Sound images. High quality results are achieved with relatively efficient time cost. We also did validation work using expert manual segmentation as the ground truth. The result shows that the hybrid segmentation may have further clinical use.

  19. Construction of a radiation hybrid panel and the first yellowtail (Seriola quinqueradiata) radiation hybrid map using a nanofluidic dynamic array

    PubMed Central

    2014-01-01

    Background Yellowtail (Seriola quinqueradiata) are an economically important species in Japan. However, there are currently no methods for captive breeding and early rearing for yellowtail. Thus, the commercial cultivation of this species is reliant upon the capture of wild immature fish. Given this, there is a need to develop captive breeding techniques to reduce pressure on wild stocks and facilitate the sustainable development of yellowtail aquaculture. We constructed a whole genome radiation hybrid (RH) panel for yellowtail gene mapping and developed a framework physical map using a nanofluidic dynamic array to use SNPs (single nucleotide polymorphisms) in ESTs (expressed sequence tags) for the DNA-assisted breeding of yellowtail. Results Clonal RH cell lines were obtained after ionizing radiation; specifically, 78, 64, 129, 55, 42, and 53 clones were isolated after treatment with 3,000, 4,000, 5,000, 6,000, 8,000, or 10,000 rads, respectively. A total of 421 hybrid cell lines were obtained by fusion with mouse B78 cells. Ninety-four microsatellite markers used in the genetic linkage map were genotyped using the 421 hybrid cell lines. Based upon marker retention and genome coverage, we selected 93 hybrid cell lines to form an RH panel. Importantly, we performed the first genotyping of yellowtail markers in an RH panel using a nanofluidic dynamic array (Fluidigm, CA, USA). Then, 580 markers containing ESTs and SNPs were mapped in the first yellowtail RH map. Conclusions We successfully developed a yellowtail RH panel to facilitate the localization of markers. Using this, a framework RH map was constructed with 580 markers. This high-density physical map will serve as a useful tool for the identification of genes related to important breeding traits using genetic structural information, such as conserved synteny. Moreover, in a comparison of 30 sequences in the RH group 1 (SQ1), yellowtail appeared to be evolutionarily closer to medaka and the green

  20. Micropolarizer arrays in the MWIR for snapshot polarimetric imaging

    NASA Astrophysics Data System (ADS)

    Kemme, S. A.; Cruz-Cabrera, A. A.; Nandy, R.; Boye, R. R.; Wendt, J. R.; Carter, T. R.; Samora, S.

    2007-04-01

    We report on the design, fabrication, and simulation of a four-state pixelated subwavelength optical device that enables mid-wave infrared (MWIR) or long-wave infrared (LWIR) snapshot polarimetric imaging. The polarization information can help to classify imaged materials and identify objects of interest for remote sensing and military applications. The fabricated pixelated polarizers have measured extinction ratios larger than 100:1 for pixel sizes greater than 9 microns by 9 microns, with transmitted signals greater than 50%. That exceeds, by 7 times, previously reported device extinction ratios for 15 micron by 15 micron pixels. Traditionally, sequential polarimetric imaging sensors produce scenes with polarization information through a series of assembled images. Snapshot polarimetric imaging collects the spatial distribution of all four Stokes' parameters simultaneously. In this way any noise due to scene movement from one frame to the next is eliminated. In this paper, we will quantify near-field and diffractive effects of the finite pixel apertures upon detection. We have designed and built an experimental setup that models a pixel within a focal plane array (FPA) to measure crosstalk from adjacent gold wiregrid micropolarizers. This configuration simulates a snapshot polarization imaging device where the two substrates are stacked; micropolarizer array substrate on top of an FPA. Modeling and measured data indicate crosstalk between the adjacent pixels up to a few microns behind the polarizer plane. Crosstalk between adjacent pixels increases uncertainty in the measured polarization states in a scene of interest. Measured and simulated data confirm that the extinction ratio of a micropolarizer pixel in a super-cell will be reduced by 17% when moving the FPA from 0.5 microns to 1.0 microns away from the polarizer. These changes in extinction ratio are significant since typical glue separation is on the order of 10 microns.

  1. CdZnTe arrays for nuclear medicine imaging

    SciTech Connect

    Barber, H.B.

    1996-12-31

    In nuclear medicine, a gamma-ray-emitting radiotracer is injected into the body, and the resulting biodistribution is imaged using a gamma camera. Current gamma cameras use a design developed by Anger. An Anger camera makes use of a slab of scintillation detector that is viewed by an array of photomultiplier tubes and uses an analog position estimation technique to determine the position of the gamma ray`s interaction. The image-forming optics is usually a multi-bore collimator made of lead. Such cameras are characterized by poor, system spatial resolution ({approximately}1 cm) due to poor detector resolution ({approximately}0.4 cm) and poor collimator performance. Arrays of semiconductor detectors are an attractive alternative to scintillators for use in gamma cameras. Semiconductor detectors have excellent energy resolution. High spatial resolution is also possible because large semiconductor detector arrays with small pixel sizes can be produced using photolithography techniques. A new crystal growth technique (high-pressure vertical Bridgman) allows production of detector grade CdTe and CdZnTe in multikilogram ingots. Although the cost of CdZnTe detectors has come down substantially in the last few years, in part because of economies of scale, costs are still more than an order of magnitude higher than those required for a commercial camera ($20--$50/gram). High detector costs are perhaps the major stumbling block to developing a semiconductor gamma camera. The photolithography techniques required to make large CdZnTe arrays have already been demonstrated. This paper discusses the recent developments made in CdZnTe detectors.

  2. Floating three-dimensional image display using micro-mirror array imaging element

    NASA Astrophysics Data System (ADS)

    Miyazaki, Daisueke; Maeda, Yuki; Maekawa, Satoshi

    2015-05-01

    Autostereoscopic three-dimensional display technologies using novel optical imaging systems based on retro-reflection with mirror arrays, a dihedral corner reflector array (DCRA) and a roof mirror array (RMA) are described. The proposed methods can generate a low-distortion aerial 3-D image with high numerical aperture on the basis of retro-reflection imaging. As the examples of 3-D displays based on retro-reflective imaging, a multi-view stereoscopic display using a DCRA and a volumetric display using a RMA were described. The multi-view stereoscopic display can achieve not only aerial image formation of display images but also that of the pupils of projectors around viewing position using a DCRA. This feature is effective in keeping consistency between accommodation and convergence cues for stereoscopic display. The volumetric display using a RMA can generate a 3-D image with natural depth information by light points are arranged in a 3-D volume using relatively simple optical configuration. This method can provide natural perception of depth and accessibility to an image. Experimental demonstrations of the generation of floating autostereoscopic images are presented to verify the validity of our proposed methods.

  3. Passive THz Imaging with Superconducting NbN microbolometer Arrays

    NASA Astrophysics Data System (ADS)

    Helistö, Panu

    2007-03-01

    Passive THz imaging applications indoors require temperature difference resolution well below 1 K and integration times down to 0.1 ms. Recently we have shown that such resolution, approaching the photon noise limit, can be achieved using an antenna-coupled superconducting microwire bolometer with about 10 K transition temperature. The bolometer signal is read out with a low-noise room-temperature amplifier, thus eliminating the need for SQUID amplifiers. The readout method utilizes electro-thermal feedback at the I-V curve minimum of a voltage-biased bolometer. At this working point, the very high power gain of the bolometer makes noise matching of the readout to the detector straightforward. The readout amplifier can be used with transition bolometers and calorimeters operating even at mK temperatures. We are presently developing a video-rate THz imager for concealed weapon detection, utilizing conical scanning and a 128-pixel NbN bolometer array, cooled down to 4 K with a pulse-tube cryocooler. We will characterize the bolometer arrays and the readout electrically and compare the results with the theory. We will also present the design of the system and results of preliminary imaging experiments. The work is done in collaboration between VTT, Millilab and NIST.

  4. 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).

  5. 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

  6. 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.

  7. 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.

  8. Imaging Radio Photospheres with the Jansky Very Large Array

    NASA Astrophysics Data System (ADS)

    Matthews, L. D.; Reid, M. J.; Menten, K. M.

    2015-08-01

    Using the Jansky Very Large Array (JVLA), we have imaged the radio photosphere of the long-period variable star W Hya at 45 GHz (˜ 7 mm) with a resolution of ˜ 40 mas. Our data reveal a non-spherical photospheric shape, consistent with earlier measurements. We also find evidence for an elongation along PA ≍ -5°, the orientation of which is consistent with the previously measured projected magnetic field direction and an extension in the 18 μm dust emission, both at larger scales.

  9. Techniques for radar imaging using a wideband adaptive array

    NASA Astrophysics Data System (ADS)

    Curry, Mark Andrew

    A microwave imaging approach is simulated and validated experimentally that uses a small, wideband adaptive array. The experimental 12-element linear array and microwave receiver uses stepped frequency CW signals from 2--3 GHz and receives backscattered energy from short range objects in a +/-90° field of view. Discone antenna elements are used due to their wide temporal bandwidth, isotropic azimuth beam pattern and fixed phase center. It is also shown that these antennas have very low mutual coupling, which significantly reduces the calibration requirements. The MUSIC spectrum is used as a calibration tool. Spatial resampling is used to correct the dispersion effects, which if not compensated causes severe reduction in detection and resolution for medium and large off-axis angles. Fourier processing provides range resolution and the minimum variance spectral estimate is employed to resolve constant range targets for improved angular resolution. Spatial smoothing techniques are used to generate signal plus interference covariance matrices at each range bin. Clutter affects the angular resolution of the array due to the increase in rank of the signal plus clutter covariance matrix, whereas at the same time the rank of this matrix is reduced for closely spaced scatterers due to signal coherence. A method is proposed to enhance angular resolution in the presence of clutter by an approximate signal subspace projection (ASSP) that maps the received signal space to a lower effective rank approximation. This projection operator has a scalar control parameter that is a function of the signal and clutter amplitude estimates. These operations are accomplished without using eigendecomposition. The low sidelobe levels allow the imaging of the integrated backscattering from the absorber cones in the chamber. This creates a fairly large clutter signature for testing ASSP. We can easily resolve 2 dihedrals placed at about 70% of a beamwidth apart, with a signal to clutter ratio

  10. Embryo selection in IVF: is polar body array comparative genomic hybridization accurate enough?

    PubMed

    Scriven, Paul N; Ogilvie, Caroline Mackie; Khalaf, Yacoub

    2012-04-01

    The emergence of the array comparative genomic hybridization technique (aCGH) is considered an advance in preimplantation genetic testing. Analysis of the recently published pilot study using polar body aCGH indicates that the test accuracy compares favourably with the fluorescence in situ hybridization technique although a substantial number of euploid zygotes are still likely to be excluded incorrectly. A sound argument against selection in principle has recently been published, based on accumulating evidence that potentially all embryos can now be cryopreserved and transferred in subsequent frozen replacement cycles without impairing pregnancy rates. We suggest that vitrification and serial transfer without testing are likely to give patients the best chance for a successful pregnancy, and avoid the use of an expensive technology. PMID:22328558

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

    PubMed

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

    2012-04-01

    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. PMID:22370878

  12. Development of single-cell array for large-scale DNA fluorescence in situ hybridization

    PubMed Central

    Liu, Yingru; Kirkland, Brett; Shirley, James; Wang, Zhibin; Zhang, Peipei; Stembridge, Jacquelyn; Wong, Wilson; Takebayashi, Shin-ichiro; Gilbert, David M.; Lenhert, Steven

    2013-01-01

    DNA fluorescence in situ hybridization (FISH) is a powerful cytogenetic assay, but conventional sample-preparation methods for FISH do not support large-scale high-throughput data acquisition and analysis, which are potentially useful for several biomedical applications. To address this limitation, we have developed a novel FISH sample-preparation method based on generating a centimetre-sized cell array, in which all cells are precisely positioned and separated from their neighbours. This method is simple and easy and capable of patterning nonadherent human cells. We have successfully performed DNA FISH on the single-cell arrays, which facilitate analysis of FISH results with the FISH-FINDER computer program. PMID:23370691

  13. 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.

  14. Scattering and radiation analysis of three-dimensional cavity arrays via a hybrid finite element method

    NASA Technical Reports Server (NTRS)

    Jin, Jian-Ming; Volakis, John L.

    1992-01-01

    A hybrid numerical technique is presented for a characterization of the scattering and radiation properties of three-dimensional cavity arrays recessed in a ground plane. The technique combines the finite element and boundary integral methods and invokes Floquet's representation to formulate a system of equations for the fields at the apertures and those inside the cavities. The system is solved via the conjugate gradient method in conjunction with the Fast Fourier Transform (FFT) thus achieving an O(N) storage requirement. By virtue of the finite element method, the proposed technique is applicable to periodic arrays comprised of cavities having arbitrary shape and filled with inhomogeneous dielectrics. Several numerical results are presented, along with new measured data, which demonstrate the validity, efficiency, and capability of the technique.

  15. Hybrid simulations of Z-Pinches in support of wire array implosion experiments at NTF.

    SciTech Connect

    Sotnikov, Vladimir Isaakovich; Oliver, Bryan Velten; Ivanov, Vladimir V.; LePell, Paul David; Fedin, Dmitry; Kantsyrev, Victor Leonidovich; Coverdale, Christine Anne; Travnicek, P.; Deeney, Christopher; Hellinger, P.; Jones, B.; Leboeuf, J. N.; Cowan, Thomas E.; Safronova, Alla S.

    2005-07-01

    Three-dimensional hybrid simulation of a plasma current-carrying column reveal two different regimes of sausage and kink instability development. In the first regime, with small Hall parameter, development of instabilities leads to the appearance of large-scale axial perturbations and eventually to bending of the plasma column. In the second regime, with a four-times-larger Hall parameter, small-scale perturbations dominate and no bending of the plasma column is observed. Simulation results are compared with laser probing experimental data obtained during wire array implosions on the Zebra pulse power generator at the Nevada Terawatt Facility.

  16. 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

  17. Hybrid photoacoustic and optical imaging of pigments in vegetative tissues.

    PubMed

    Tserevelakis, George J; Tsagkaraki, Margarita; Zacharakis, Giannis

    2016-09-01

    Pigments in vegetative tissues have been a subject of intense research during the previous decades, since they play an active role in several molecular mechanisms regarding plants' physiology and function. Towards this direction, the imaging modality that has been extensively employed and represents the state of the art for mapping pigments' distribution is confocal microscopy. Despite the advantage of a high spatial resolution however, confocal microscopy provides a rather limited imaging depth and requires necessarily strong fluorescence properties from the specimen under observation. To overcome such limitations, we propose a hybrid, photoacoustic and optical imaging methodology for the delineation of various vegetative pigments, such as chlorophylls, anthocyanins and betalains in different plant species. The superior sensitivity and the high contrast complementarity of the hybrid technique, render it a powerful alternative to the conventional fluorescence imaging modalities, significantly expanding the current state of the art. PMID:27019381

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

    PubMed Central

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

    2015-01-01

    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 as applied to other bacterial species as long as multiple whole genome sequences are available that collectively capture the vast majority of the species supragenome. PMID:25641101

  19. 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

  20. Volume coil based on hybridized resonators for magnetic resonance imaging

    NASA Astrophysics Data System (ADS)

    Jouvaud, C.; Abdeddaim, R.; Larrat, B.; de Rosny, J.

    2016-01-01

    We present an electromagnetic device based on hybridization of four half-wavelength dipoles which increases the uniformity and the strength of the radio-frequency (RF) field of a Magnetic Resonant Imaging (MRI) apparatus. Numerical results show that this Hybridized Coil (HC) excited with a classical loop coil takes advantage of the magnetic hybrid modes. The distribution of the RF magnetic field is experimentally confirmed on a 7-T MRI with a gelatin phantom. Finally, the HC is validated in vivo by imaging the head of an anesthetized rat. We measure an overall increase of the signal to noise ratio with up to 2.4 fold increase in regions of interest far from the active loop coil.

  1. 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.

  2. Array imaging of austenitic welds by measuring weld material map

    NASA Astrophysics Data System (ADS)

    Fan, Z.; Lowe, M.

    2014-02-01

    It is difficult to inspect for defects in austenitic welds ultrasonically due to complicated material properties inside the weld. Weld microstructures typically lead to weld stiffnesses that are both anisotropic and inhomogeneous, so that ultrasonic waves tend to deviate and scatter. A weld performance map is commonly used to describe how the material properties vary throughout the weld, and this idea has been applied to wave propagation models. In this work, we developed a non-destructive method to measure this map using ultrasonic arrays. A material model (previously published by others) with a small number of parameters has been applied to describe the weld performance map. It uses the information of the welding procedure and rules for crystalline growth to predict the orientations, therefore it has a good physical foundation. An inverse model has then been developed to measure the weld performance map based on the matching of predictions by the ray tracing method to selected experimental array measurements. The process is validated by both finite element models and experiments. The results have been applied to correct array images to compensate for deviations of the ultrasonic rays.

  3. High-frequency ultrasound annular array imaging. Part II: digital beamformer design and imaging.

    PubMed

    Hu, Chang-Hong; Snook, Kevin A; Cao, Pei-Jie; Shung, K Kirk

    2006-02-01

    This is the second part of a two-paper series reporting a recent effort in the development of a high-frequency annular array ultrasound imaging system. In this paper an imaging system composed of a six-element, 43 MHz annular array transducer, a six-channel analog front-end, a field programmable gate array (FPGA)-based beamformer, and a digital signal processor (DSP) microprocessor-based scan converter will be described. A computer is used as the interface for image display. The beamformer that applies delays to the echoes for each channel is implemented with the strategy of combining the coarse and fine delays. The coarse delays that are integer multiples of the clock periods are achieved by using a first-in-first-out (FIFO) structure, and the fine delays are obtained with a fractional delay (FD) filter. Using this principle, dynamic receiving focusing is achieved. The image from a wire phantom obtained with the imaging system was compared to that from a prototype ultrasonic backscatter microscope with a 45 MHz single-element transducer. The improved lateral resolution and depth of field from the wire phantom image were observed. Images from an excised rabbit eye sample also were obtained, and fine anatomical structures were discerned. PMID:16529105

  4. Construction and hyperspectral imaging of quantum dot lysate arrays.

    PubMed

    Rosenblatt, Kevin P; Huebschman, Michael L; Garner, Harold R

    2012-01-01

    The emerging field of proteomic molecular profiling will be driven by new technologies that can measure dozens to hundreds of proteins from a small sample input from a patient's biopsy. Lysate arrays, or reverse-phase protein microarrays, provide a platform for complex mixtures of proteins extracted from cells and tissues to be directly immobilized onto a solid support (such as a biochip with protein binding capacity) in diminutive volumes (picoliter-to-nanoliter). The proteins are spotted using precision robotics and then quantitatively assayed using primary antibodies; important posttranslational modifications, such as phosphorylations that are important for protein activation, may also be assayed to provide an estimate of the regulation of cellular signaling. Until recently, chromogenic signals and fluorescence (using organic fluorophores) detection were two strategies relied upon for signal detection. Emerging regents such as quantum dots (Qdot® nanocrystals; QD) are now employed for improved performance. QD embody a more versatile detection system because the robust signals may be time averaged and the narrow spectral emissions enable many protein targets to be quantified within the same lysate spot. Previously, we found that commercially available pegylated, streptavidin-conjugated QD were effective detection agents, with low-background affinities to spurious components within heterogeneous protein mixtures. Hyperspectral imaging allows the simultaneous detection of the different colored QD reagents within a single lysate spot. Here, we described the construction and imaging of QD lysate arrays. This technology is an emerging, enabling tool within the exciting, clinically oriented field of clinical tissue proteomics. PMID:22081354

  5. 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.

  6. Hybridization modeling of oligonucleotide SNP arrays for accurate DNA copy number estimation

    PubMed Central

    Wan, Lin; Sun, Kelian; Ding, Qi; Cui, Yuehua; Li, Ming; Wen, Yalu; Elston, Robert C.; Qian, Minping; Fu, Wenjiang J

    2009-01-01

    Affymetrix SNP arrays have been widely used for single-nucleotide polymorphism (SNP) genotype calling and DNA copy number variation inference. Although numerous methods have achieved high accuracy in these fields, most studies have paid little attention to the modeling of hybridization of probes to off-target allele sequences, which can affect the accuracy greatly. In this study, we address this issue and demonstrate that hybridization with mismatch nucleotides (HWMMN) occurs in all SNP probe-sets and has a critical effect on the estimation of allelic concentrations (ACs). We study sequence binding through binding free energy and then binding affinity, and develop a probe intensity composite representation (PICR) model. The PICR model allows the estimation of ACs at a given SNP through statistical regression. Furthermore, we demonstrate with cell-line data of known true copy numbers that the PICR model can achieve reasonable accuracy in copy number estimation at a single SNP locus, by using the ratio of the estimated AC of each sample to that of the reference sample, and can reveal subtle genotype structure of SNPs at abnormal loci. We also demonstrate with HapMap data that the PICR model yields accurate SNP genotype calls consistently across samples, laboratories and even across array platforms. PMID:19586935

  7. Unexploded ordnance detection using imaging giant magnetoresistive (GMR) sensor arrays

    SciTech Connect

    Chaiken, A., LLNL

    1997-05-06

    False positive detections account for a great part of the expense associated with unexploded ordnance (UXO) remediation. Presently fielded systems like pulsed electromagnetic induction systems and cesium-vapor magnetometers are able to distinguish between UXO and other metallic ground clutter only with difficulty. The discovery of giant magnetoresistance (GMR) has led to the development of a new generation of integrated-circuit magnetic sensors that are far more sensitive than previously available room-temperature-operation electronic devices. The small size of GMR sensors makes possible the construction of array detectors that can be used to image the flux emanating from a ferrous object or from a non-ferrous object with eddy currents imposed by an external coil. The purpose of a GMR-based imaging detector would be to allow the operator to easily distinguish between UXO and benign objects (like shrapnel or spent bullets) that litter formerly used defense sites (FUDS). In order to demonstrate the potential of a GMR-based imaging technology, a crude magnetic imaging system has been constructed using commercially available sensors. The ability to roughly determine the outline and disposition of magnetic objects has been demonstrated. Improvements to the system which are necessary to make it into a high-performance UXO detector are outlined.

  8. 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.

  9. An Effective and Fast Hybrid Framework for Color Image Retrieval

    NASA Astrophysics Data System (ADS)

    Walia, Ekta; Vesal, Sulaiman; Pal, Aman

    2014-11-01

    This paper presents a novel, fast and effective hybrid framework for color image retrieval through combination of all the low level features, which gives higher retrieval accuracy than other such systems. The color moment (CMs), angular radial transform descriptor and edge histogram descriptor (EHD) features are exploited to capture color, shape and texture information respectively. A multistage framework is designed to imitate human perception so that in the first stage, images are retrieved based on their CMs and then the shape and texture descriptors are utilized to identify the closest matches in the second stage. The scheme employs division of images into non-overlapping regions for effective computation of CMs and EHD features. To demonstrate the efficacy of this framework, experiments are conducted on Wang's, VisTex and OT-Scene databases. Inspite of its multistage design, the system is observed to be faster than other hybrid approaches.

  10. An LED-array-based range imaging system used for enhancing three-dimensional imaging

    NASA Astrophysics Data System (ADS)

    Wang, Huanqin; Xu, Jun; He, Deyong; Zhao, Tianpeng; Wang, Anting; Ming, Hai; Kong, Deyi

    2010-11-01

    An LED-array-based range imaging system is proposed for three-dimensional (3-D) shape measurement. The range image is obtained by time-division electronic scanning of the LED Time-of-Flight (TOF) range finders in array, and no complex mechanical scanning is needed. By combining with a low cost CCD/CMOS sensor for capturing the twodimensional (2-D) image, the proposed range imaging system can be used to accomplish a high quality 3-D imaging. A sophisticated co-lens optical path is designed to assure the natural registration between the range image and 2-D image. Experimental tests for evaluation of the imaging system performance are described. It was found that the 3-D images can be acquired at a rate of 10 frames per second with a depth resolution better than 5mm in the range of 50 - 1000mm, which is sufficient for many practical applications, including the obstacle detection in robotics, machine automation, 3-D vision, virtual reality games and 3-D video.

  11. 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.

  12. Multimodal Iron Oxide Nanoparticles for Hybrid Biomedical Imaging

    PubMed Central

    Heidt, Timo; Nahrendorf, Matthias

    2012-01-01

    Iron oxide core nanoparticles are attractive imaging agents because their material properties allow the tuning of pharmacokinetics as well as attachment of multiple moieties to their surface. In addition to affinity ligands, these include fluorochromes and radioisotopes for detection with optical and nuclear imaging. As the iron oxide core can be detected by MRI, options for combining imaging modalities are manifold. Already, preclinical imaging strategies combine non-invasive imaging with higher resolution techniques such as intravital microscopy to gain unprecedented insight into steady state biology and disease. Going forward, hybrid iron oxide nanoparticles will likely help to merge modalities, creating a synergy that enables imaging in basic research and, potentially, also in the clinic. PMID:23065771

  13. 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

  14. Detection limit of intragenic deletions with targeted array comparative genomic hybridization

    PubMed Central

    2013-01-01

    Background Pathogenic mutations range from single nucleotide changes to deletions or duplications that encompass a single exon to several genes. The use of gene-centric high-density array comparative genomic hybridization (aCGH) has revolutionized the detection of intragenic copy number variations. We implemented an exon-centric design of high-resolution aCGH to detect single- and multi-exon deletions and duplications in a large set of genes using the OGT 60 K and 180 K arrays. Here we describe the molecular characterization and breakpoint mapping of deletions at the smaller end of the detectable range in several genes using aCGH. Results The method initially implemented to detect single to multiple exon deletions, was able to detect deletions much smaller than anticipated. The selected deletions we describe vary in size, ranging from over 2 kb to as small as 12 base pairs. The smallest of these deletions are only detectable after careful manual review during data analysis. Suspected deletions smaller than the detection size for which the method was optimized, were rigorously followed up and confirmed with PCR-based investigations to uncover the true detection size limit of intragenic deletions with this technology. False-positive deletion calls often demonstrated single nucleotide changes or an insertion causing lower hybridization of probes demonstrating the sensitivity of aCGH. Conclusions With optimizing aCGH design and careful review process, aCGH can uncover intragenic deletions as small as dozen bases. These data provide insight that will help optimize probe coverage in array design and illustrate the true assay sensitivity. Mapping of the breakpoints confirms smaller deletions and contributes to the understanding of the mechanism behind these events. Our knowledge of the mutation spectra of several genes can be expected to change as previously unrecognized intragenic deletions are uncovered. PMID:24304607

  15. A hybrid features based image matching algorithm

    NASA Astrophysics Data System (ADS)

    Tu, Zhenbiao; Lin, Tao; Sun, Xiao; Dou, Hao; Ming, Delie

    2015-12-01

    In this paper, we present a novel image matching method to find the correspondences between two sets of image interest points. The proposed method is based on a revised third-order tensor graph matching method, and introduces an energy function that takes four kinds of energy term into account. The third-order tensor method can hardly deal with the situation that the number of interest points is huge. To deal with this problem, we use a potential matching set and a vote mechanism to decompose the matching task into several sub-tasks. Moreover, the third-order tensor method sometimes could only find a local optimum solution. Thus we use a cluster method to divide the feature points into some groups and only sample feature triangles between different groups, which could make the algorithm to find the global optimum solution much easier. Experiments on different image databases could prove that our new method would obtain correct matching results with relatively high efficiency.

  16. 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. PMID:22868401

  17. Digital pixel CMOS focal plane array with on-chip multiply accumulate units for low-latency image processing

    NASA Astrophysics Data System (ADS)

    Little, Jeffrey W.; Tyrrell, Brian M.; D'Onofrio, Richard; Berger, Paul J.; Fernandez-Cull, Christy

    2014-06-01

    A digital pixel CMOS focal plane array has been developed to enable low latency implementations of image processing systems such as centroid trackers, Shack-Hartman wavefront sensors, and Fitts correlation trackers through the use of in-pixel digital signal processing (DSP) and generic parallel pipelined multiply accumulate (MAC) units. Light intensity digitization occurs at the pixel level, enabling in-pixel DSP and noiseless data transfer from the pixel array to the peripheral processing units. The pipelined processing of row and column image data prior to off chip readout reduces the required output bandwidth of the image sensor, thus reducing the latency of computations necessary to implement various image processing systems. Data volume reductions of over 80% lead to sub 10μs latency for completing various tracking and sensor algorithms. This paper details the architecture of the pixel-processing imager (PPI) and presents some initial results from a prototype device fabricated in a standard 65nm CMOS process hybridized to a commercial off-the-shelf short-wave infrared (SWIR) detector array.

  18. 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. PMID:25430218

  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. Fluorescent In Situ Hybridization in Suspension by Imaging Flow Cytometry.

    PubMed

    Maguire, Orla; Wallace, Paul K; Minderman, Hans

    2016-01-01

    The emergence of imaging flow cytometry (IFC) has brought novel applications exploiting its advantages over conventional flow cytometry and microscopy. One of the new applications is fluorescence in situ hybridization in suspension (FISH-IS). Conventional FISH is a slide-based approach in which the spotlike imagery resulting from hybridization with fluorescently tagged probes is evaluated by fluorescence microscopy. The FISH-IS approach evaluated by IFC enables the evaluation of tens to hundreds of thousands of cells in suspension and the analysis can be automated and standardized diminishing operator bias from the analysis. The high cell number throughput of FISH-IS improves the detection of rare events compared to conventional FISH. The applicability of FISH-IS is currently limited to detection of abnormal quantitative differences of hybridization targets such as occur in numerical chromosome abnormalities, deletions and amplifications.Here, we describe a protocol for FISH-IS using chromosome enumeration probes as an example. PMID:27460240

  1. 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.

  2. 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.

  3. 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.

  4. Imaging protoplanetary disks with a square kilometer array

    NASA Astrophysics Data System (ADS)

    Wilner, D. J.

    2004-12-01

    The recent detections of extrasolar giant planets has revealed a surprising diversity of planetary system architectures, with many very unlike our Solar System. Understanding the origin of this diversity requires multi-wavelength studies of the structure and evolution of the protoplanetary disks that surround young stars. Radio astronomy and the square kilometer array (SKA) will play a unique role in these studies by imaging thermal dust emission in a representative sample of protoplanetary disks at unprecedented sub-AU scales in the innermost regions, including the "habitable zone" that lies within a few AU of the central stars. Radio observations will probe the evolution of dust grains up to centimeter-sized "pebbles", the critical first step in assembling giant planet cores and terrestrial planets, through the wavelength dependence of dust emissivity, which provides a diagnostic of particle size. High resolution images of dust emission will show directly mass concentrations and features in disk surface density related to planet building, in particular the radial gaps opened by tidal interactions between planets and disks, and spiral waves driven by embedded protoplanets. Moreover, because orbital timescales are short in the inner disk, synoptic studies over months and years will show proper motions and allow for the tracking of secular changes in disk structure. SKA imaging of protoplanetary disks will reach into the realm of rocky planets for the first time, and they will help clarify the effects of the formation of giant planets on their terrestrial counterparts.

  5. Assessment of scanning model observers with hybrid SPECT images

    NASA Astrophysics Data System (ADS)

    Gifford, H. C.; Pretorius, P. H.; King, M. A.

    2008-03-01

    The purpose of this work was to test procedures for applying scanning model observers in order to predict human-observer lesion-detection performance with hybrid images. Hybrid images consist of clinical backgrounds with simulated abnormalities. The basis for this investigation was detection and localization of solitary pulmonary nodules (SPN) in SPECT lung images, and our overall goal has been to determine the extent to which detection of SPN could be improved by proper modeling of the acquisition physics during the iterative reconstruction process. Towards this end, we conducted human-observer localization ROC (LROC) studies to optimize the number of iterations and the postfiltering of four rescaled block-iterative (RBI) reconstruction strategies with various combinations of attenuation correction (AC), scatter correction (SC), and system-resolution correction (RC). This observer data was then used to evaluate a scanning channelized nonprewhitening model observer. A standard "background-known-exactly" (BKE) task formulation overstated the prior knowledge and training that human observers had about the hybrid images. Results from a quasi-BKE task that preserved some degree of structural noise in the detection task demonstrated better agreement with the humans.

  6. Combatting infrared focal plane array nonuniformity noise in imaging polarimeters

    NASA Astrophysics Data System (ADS)

    Ratliff, Bradley M.; Kumar, Rakesh; Black, Wiley; Boger, James K.; Tyo, J. Scott

    2005-08-01

    One of the most significant challenges in performing infrared (IR) polarimetery is the focal plane array (FPA) nonuniformity (NU) noise that is inherent in virtually all IR photodetector technologies that operate in the midwave IR (MWIR) or long-wave IR (LWIR). NU noise results from pixel-to-pixel variations in the repsonsivity of the photodetectors. This problem is especially severy in the microengineered IR FPA materials like HgCdTe and InSb, as well as in uncooled IR microbolometer sensors. Such problems are largely absent from Si based visible spectrum FPAs. The pixel response is usually a variable nonlinear response function, and even when the response is linearized over some range of temperatures, the gain and offset of the resulting response is usually highly variable. NU noise is normally corrected by applying a linear calibration to the data, but the resulting imagery still retains residual nonuniformity due to the nonlinearity of the photodetector responses. This residual nonuniformity is particularly troublesome for polarimeters because of the addition and subtraction operations that must be performed on the images in order to construct the Stokes parameters or other polarization products. In this paper we explore the impact of NU noise on full stokes and linear-polarization-only IR polarimeters. We compare the performance of division of time, division of amplitude, and division of array polarimeters in the presence of both NU and temporal noise, and assess the ability of calibration-based NU correction schemes to clean up the data.

  7. Time-Domain Fluorescence Lifetime Imaging Techniques Suitable for Solid-State Imaging Sensor Arrays

    PubMed Central

    Li, David Day-Uei; Ameer-Beg, Simon; Arlt, Jochen; Tyndall, David; Walker, Richard; Matthews, Daniel R.; Visitkul, Viput; Richardson, Justin; Henderson, Robert K.

    2012-01-01

    We have successfully demonstrated video-rate CMOS single-photon avalanche diode (SPAD)-based cameras for fluorescence lifetime imaging microscopy (FLIM) by applying innovative FLIM algorithms. We also review and compare several time-domain techniques and solid-state FLIM systems, and adapt the proposed algorithms for massive CMOS SPAD-based arrays and hardware implementations. The theoretical error equations are derived and their performances are demonstrated on the data obtained from 0.13 μm CMOS SPAD arrays and the multiple-decay data obtained from scanning PMT systems. In vivo two photon fluorescence lifetime imaging data of FITC-albumin labeled vasculature of a P22 rat carcinosarcoma (BD9 rat window chamber) are used to test how different algorithms perform on bi-decay data. The proposed techniques are capable of producing lifetime images with enough contrast. PMID:22778606

  8. 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.

  9. Photon-Counting Arrays for Time-Resolved Imaging.

    PubMed

    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

  10. 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

  11. 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.

  12. Ideal and non-ideal MHD regimes of wire array implosion obtained in 3D hybrid simulations and observed during experiments at NTF.

    SciTech Connect

    Sotnikov, Vladimir Isaakovich; Fiala, V.; Oliver, Bryan Velten; Ivanov, Vladimir V.; LePell, Paul David; Fedin, Dmitry; Mehlhorn, Thomas Alan; Kantsyrev, Victor Leonidovich; Coverdale, Christine Anne; Travnicek, P.; Hellinger, P.; Deeney, Christopher; Jones, Brent Manley; Safronova, Alla S.; Leboeuf, J. N.; Cowan, Thomas E.

    2004-11-01

    Recent 3D hybrid simulation of a plasma current-carrying column revealed two regimes of sausage and kink instability development. In the first regime, with small Hall parameter, development of instabilities leads to appearance of large-scale axial perturbations and eventually to the bending of the plasma column. In the second regime, with five times larger Hall parameter, small-scale perturbations dominated and no bending of the plasma column was observed. Simulation results are compared to recent experimental data, including laser probing, x-ray spectroscopy and time-gated x-ray imaging during wire array implosions at NTF.

  13. 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

  14. Hybrid regularization image restoration algorithm based on total variation

    NASA Astrophysics Data System (ADS)

    Zhang, Hongmin; Wang, Yan

    2013-09-01

    To reduce the noise amplification and ripple phenomenon in the restoration result by using the traditional Richardson-Lucy deconvolution method, a novel hybrid regularization image restoration algorithm based on total variation is proposed in this paper. The key ides is that the hybrid regularization terms are employed according to the characteristics of different regions in the image itself. At the same time, the threshold between the different regularization terms is selected according to the golden section point which takes into account the human eye's visual feeling. Experimental results show that the restoration results of the proposed method are better than that of the total variation Richardson-Lucy algorithm both in PSNR and MSE, and it has the better visual effect simultaneously.

  15. Tilted Microstrip Phased Arrays With Improved Electromagnetic Decoupling for Ultrahigh-Field Magnetic Resonance Imaging

    PubMed Central

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

    2014-01-01

    Abstract 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. PMID:25526481

  16. STEM image simulation with hybrid CPU/GPU programming.

    PubMed

    Yao, Y; Ge, B H; Shen, X; Wang, Y G; Yu, R C

    2016-07-01

    STEM image simulation is achieved via hybrid CPU/GPU programming under parallel algorithm architecture to speed up calculation on a personal computer (PC). To utilize the calculation power of a PC fully, the simulation is performed using the GPU core and multi-CPU cores at the same time to significantly improve efficiency. GaSb and an artificial GaSb/InAs interface with atom diffusion have been used to verify the computation. PMID:27093687

  17. Semiconductor arrays with multiplexer readout for gamma-ray imaging: results for a 48 × 48 Ge array

    NASA Astrophysics Data System (ADS)

    Barber, H. B.; Augustine, F. L.; Barrett, H. H.; Dereniak, E. L.; Matherson, K. L.; Meyers, T. J.; Perry, D. L.; Venzon, J. E.; Woolfenden, J. M.; Young, E. T.

    1994-12-01

    We are developing a new kind of gamma-ray imaging device that has sub-millimeter spatial resolution and excellent energy resolution. The device is composed of a slab of semiconductor detector partitioned into an array of detector cells by photolithography and connected to a monolithic circuit chip called a multiplexer (MUX) for readout. Our application is for an ultra-high-resolution SPECT system for functional brain imaging using an injected radiotracer. We report here on results obtained with a Hughes 48 × 48 Ge PIN-photodiode array with MUX readout, originally developed as an infrared focal-plane-array imaging sensor. The device functions as an array of individual gamma-ray detectors with minimal interpixel crosstalk. Linearity of energy response is excellent up to at least 140 keV. The array exhibits excellent energy resolution, ˜ 2 keV at ≤ 140 keV or 1.5% FWHM at 140 keV. The energy resolution is dominated by MUX readout noise and so should improve with MUX optimization for gamma-ray detection. The spatial resolution of the 48 × 48 Ge array is essentially the same as the pixel spacing, 125 μm. The quantum efficiency is limited by the thin Ge detector (0.25 mm), but this approach is readily applicable to thicker Ge detectors and room-temperature semiconductor detectors such as CdTe, HgI 2 and CdZnTe.

  18. Dual-mode photosensitive arrays based on the integration of liquid crystal microlenses and CMOS sensors for obtaining the intensity images and wavefronts of objects.

    PubMed

    Tong, Qing; Lei, Yu; Xin, Zhaowei; Zhang, Xinyu; Sang, Hongshi; Xie, Changsheng

    2016-02-01

    In this paper, we present a kind of dual-mode photosensitive arrays (DMPAs) constructed by hybrid integration a liquid crystal microlens array (LCMLA) driven electrically and a CMOS sensor array, which can be used to measure both the conventional intensity images and corresponding wavefronts of objects. We utilize liquid crystal materials to shape the microlens array with the electrically tunable focal length. Through switching the voltage signal on and off, the wavefronts and the intensity images can be acquired through the DMPAs, sequentially. We use white light to obtain the object's wavefronts for avoiding losing important wavefront information. We separate the white light wavefronts with a large number of spectral components and then experimentally compare them with single spectral wavefronts of typical red, green and blue lasers, respectively. Then we mix the red, green and blue wavefronts to a composite wavefront containing more optical information of the object. PMID:26906768

  19. 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

  20. Global synchronization in arrays of coupled Lurie systems with both time-delay and hybrid coupling

    NASA Astrophysics Data System (ADS)

    Li, Tao; Song, Aiguo; Fei, Shumin; Wang, Ting

    2011-01-01

    In this paper, we propose and study an array of coupled delayed Lurie systems with hybrid coupling, which is composed of constant coupling, state delay coupling, and distributed delay coupling. Together with Lyapunov-Krasovskii functional method and Kronecker product properties, two novel synchronization criteria are presented within linear matrix inequalities based on generalized convex combination, in which these conditions are heavily dependent on the upper and lower bounds of state delay and distributed one. Through adjusting inner coupling matrix parameters in the derived results, we can realize the designing and applications of the addressed systems by referring to Matlab LMI Toolbox. The efficiency and applicability of the proposed criteria can be demonstrated by three numerical examples with simulations.

  1. Hybrid sample-inverted reflow and soft-lithography technique for fabrication of conicoid microlens arrays.

    PubMed

    He, Miao; Yuan, Xiaocong; Bu, Jing; Cheong, Wai Chye

    2005-07-01

    We report a cost-effective fabrication method, with a combination of the sample-inverted reflow technique and the soft-lithography replication method, to fabricate conicoid refractive microlens arrays (MLAs), including hyperboloid, paraboloid, and ellipsoid MLAs in inorganic-organic hybrid SiO2-ZrO2 solgel material. The fabrication procedures involve two basic steps. First, a master of the conicoid MLA was made in photoresist by the sample-inverted reflow technique. Second, we built a negative mold of the master by casting polydimethylsiloxane (PDMS) onto a silicone elastomer against the master, and then the profile was imprinted onto the solgel glass. As a result, the fabricated solgel MLAs have been obtained with excellent smooth profiles, having negligible discrepancies from the profiles of ideal conicoid MLAs. PMID:16004061

  2. Hybrid sample-inverted reflow and soft-lithography technique for fabrication of conicoid microlens arrays

    NASA Astrophysics Data System (ADS)

    He, Miao; Yuan, Xiaocong; Bu, Jing; Chye Cheong, Wai

    2005-07-01

    We report a cost-effective fabrication method, with a combination of the sample-inverted reflow technique and the soft-lithography replication method, to fabricate conicoid refractive microlens arrays (MLAs), including hyperboloid, paraboloid, and ellipsoid MLAs in inorganic-organic hybrid SiO2-ZrO2 solgel material. The fabrication procedures involve two basic steps. First, a master of the conicoid MLA was made in photoresist by the sample-inverted reflow technique. Second, we built a negative mold of the master by casting polydimethylsiloxane (PDMS) onto a silicone elastomer against the master, and then the profile was imprinted onto the solgel glass. As a result, the fabricated solgel MLAs have been obtained with excellent smooth profiles, having negligible discrepancies from the profiles of ideal conicoid MLAs.

  3. A Hybrid Computational Model for Ultrasound Phased-Array Heating in Presence of Strongly Scattering Obstacles

    PubMed Central

    Botros, Youssry Y.; VanBaren, Philip; Ebbini, Emad S.

    2010-01-01

    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. PMID:9353983

  4. Imaging collective magnonic modes in 2D arrays of magnetic nanoelements.

    PubMed

    Kruglyak, V V; Keatley, P S; Neudert, A; Hicken, R J; Childress, J R; Katine, J A

    2010-01-15

    We have used time resolved scanning Kerr microscopy to image collective spin wave modes within a 2D array of magnetic nanoelements. Long wavelength spin waves are confined within the array as if it was a continuous element of the same size but with effective material properties determined by the structure of the array and its constituent nanoelements. The array is an example of a magnonic metamaterial, the demonstration of which provides new opportunities within the emerging field of magnonics. PMID:20366622

  5. Imaging Collective Magnonic Modes in 2D Arrays of Magnetic Nanoelements

    NASA Astrophysics Data System (ADS)

    Kruglyak, V. V.; Keatley, P. S.; Neudert, A.; Hicken, R. J.; Childress, J. R.; Katine, J. A.

    2010-01-01

    We have used time resolved scanning Kerr microscopy to image collective spin wave modes within a 2D array of magnetic nanoelements. Long wavelength spin waves are confined within the array as if it was a continuous element of the same size but with effective material properties determined by the structure of the array and its constituent nanoelements. The array is an example of a magnonic metamaterial, the demonstration of which provides new opportunities within the emerging field of magnonics.

  6. 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.

  7. 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.

  8. The effective image denoising method for MEMS based IR image arrays

    NASA Astrophysics Data System (ADS)

    Dong, Liquan; Liu, Xiaohua; Zhao, Yuejin; Liu, Ming; Hui, Mei; Zhou, Xiaoxiao

    2008-12-01

    MEMS have become viable systems to utilize for uncooled infrared imaging in recent years. They offer advantages due to their simplicity, low cost and scalability to high-resolution FPAs without prohibitive increase in cost. An uncooled thermal detector array with low NETD is designed and fabricated using MEMS bimaterial microcantilever structures that bend in response to thermal change. The IR images of objects obtained by these FPAs are readout by an optical method. For the IR images, processed by a sparse representation-based image denoising and inpainting algorithm, which generalizing the K-Means clustering process, for adapting dictionaries in order to achieve sparse signal representations. The processed image quality is improved obviously. Great compute and analysis have been realized by using the discussed algorithm to the simulated data and in applications on real data. The experimental results demonstrate, better RMSE and highest Peak Signal-to-Noise Ratio (PSNR) compared with traditional methods can be obtained. At last we discuss the factors that determine the ultimate performance of the FPA. And we indicated that one of the unique advantages of the present approach is the scalability to larger imaging arrays.

  9. 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

  10. A Simplified Sum-Frequency Vibrational Imaging Setup Used for Imaging Lipid Bilayer Arrays

    PubMed Central

    Smith, Kathryn A.; Conboy, John C.

    2012-01-01

    Given the complexity of cell membranes, there is a need for an analytical technique which can explore the physical properties of lipid membranes in a high-throughput and noninvasive manner. A simplified sum-frequency vibrational imaging (SFVI) setup has been developed and characterized using asymmetrically prepared 1,2-distearoyl-sn-glycero-3-phosphocholine (DSPC):1,2-distearoyl(d70)-sn-glycero-3-phosphocholine (DSPC-d70) lipid bilayer arrays. Exploiting the vibrational selectivity and inherent symmetry constraints of sum-frequency generation, SFVI was successfully used to probe the transition temperature of a patterned DSPC:DSPC-d70 lipid bilayer array. SFVI was also used to study the phase behavior in a multi-component micropatterned lipid bilayer array (MLBA) prepared using three different binary lipid mixtures (1,2-dioleoyl-sn-glycero-3-phosphocholine (DOPC):DSPC, DOPC:1,2-dipalmitoyl-sn-glycero-3-phosphocholine (DPPC) and 1,2-dimyristoyl-sn-glycero-3-phosphocholine (DMPC:DSPC). This paper demonstrates that a simplified SFVI setup provides the necessary chemical imaging capabilities with the spatial resolution, sensitivity and field of view required for exploring lipid membrane properties in a high-throughput array based assay. PMID:22947074

  11. A simplified sum-frequency vibrational imaging setup used for imaging lipid bilayer arrays.

    PubMed

    Smith, Kathryn A; Conboy, John C

    2012-10-01

    Given the complexity of cell membranes, there is a need for an analytical technique which can explore the physical properties of lipid membranes in a high-throughput and noninvasive manner. A simplified sum-frequency vibrational imaging (SFVI) setup has been developed and characterized using asymmetrically prepared 1,2-distearoyl-sn-glycero-3-phosphocholine (DSPC):1,2-distearoyl(d70)-sn-glycero-3-phosphocholine (DSPC-d(70)) lipid bilayer arrays. Exploiting the vibrational selectivity and inherent symmetry constraints of sum-frequency generation, SFVI was successfully used to probe the transition temperature of a patterned DSPC:DSPC-d(70) lipid bilayer array. SFVI was also used to study the phase behavior in a multicomponent micropatterned lipid bilayer array (MLBA) prepared using three different binary lipid mixtures (1,2-dioleoyl-sn-glycero-3-phosphocholine (DOPC):DSPC, DOPC:1,2-dipalmitoyl-sn-glycero-3-phosphocholine (DPPC), and 1,2-dimyristoyl-sn-glycero-3-phosphocholine (DMPC:DSPC). This paper demonstrates that a simplified SFVI setup provides the necessary chemical imaging capabilities with the spatial resolution, sensitivity, and field of view required for exploring lipid membrane properties in a high-throughput array based assay. PMID:22947074

  12. Ultrasonic phased array inspection imaging technology for NDT of offshore platform structures

    NASA Astrophysics Data System (ADS)

    Shan, Baohua; Wang, Hua; Liang, Yongning; Duan, Zhongdong; Ou, Jinping

    2008-03-01

    In order to improve inspection result repetition and flaw ration veracity of manual ultrasonic inspection of offshore platform structure, an ultrasonic phased array inspection imaging technology for NDT of offshore platform structures is proposed in this paper. Aimed at the practical requirement of tubular joint welds inspection of offshore platform structures, the ultrasonic phased array inspection imaging system for offshore platform structures is developed, which is composed of computer, ultrasonic circuit system, scanning device, phased array transducer and inspection imaging software system. The experiment of Y shape tubular joint model of 60 degree is performed with the ultrasonic phased array inspection imaging system for offshore platform structures, the flaws characteristic could be exactly estimated and the flaws size could be measured through ultrasonic phased array inspection imaging software system for offshore platform structures. Experiment results show that the ultrasonic phased array inspection imaging technology for offshore platform structures is feasible, the ultrasonic phased array inspection imaging system could detect flaws in tubular joint model, the whole development trend of flaws is factually imaging by the ultrasonic phased array inspection technology of offshore platform structures.

  13. 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

  14. 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.

  15. 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.

  16. Hybrid tandem solar cell enhanced by a metallic hole-array as the intermediate electrode.

    PubMed

    Zhang, Xuanru; Huang, Qiuping; Hu, Jigang; Knize, Randy J; Lu, Yalin

    2014-10-20

    A metallic hole-array structure was inserted into a tandem solar cell structure as an intermediate electrode, which allows a further fabrication of a novel and efficient hybrid organic-inorganic tandem solar cell. The inserted hole-array layer reflects the higher-energy photons back to the top cell, and transmits lower-energy photons to the bottom cell via the extraordinary optical transmission (EOT) effect. In this case light absorption in both top and bottom subcells can be simultaneously enhanced via both structural and material optimizations. Importantly, this new design could remove the constraints of requiring lattice-matching and current-matching between the used two cascaded subcells in a conventional tandem cell structure, and therefore, the tunnel junction could be no longer required. As an example, a novel PCBM/CIGS tandem cell was designed and investigated. A systematic modeling study was made on the structural parameter tuning, with the period ranging from a few hundreds nanometers to over one micrometer. Surface plasmon polaritons, magnetic plasmon polaritons, localized surface plasmons, and optical waveguide modes were found to participate in the EOT and the light absorption enhancement. Impressively, more than 40% integrated power enhancement can be achieved in a variable structural parameter range. PMID:25607297

  17. 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.

  18. 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.

  19. Effect analysis and design on array geometry for coincidence imaging radar based on effective rank theory

    NASA Astrophysics Data System (ADS)

    Zha, Guofeng; Wang, Hongqiang; Yang, Zhaocheng; Cheng, Yongqiang; Qin, Yuliang

    2016-03-01

    As a complementary imaging technology, coincidence imaging radar (CIR) achieves super-resolution in real aperture staring radar imagery via employing the temporal-spatial independent array detecting (TSIAD) signals. The characters of TSIAD signals are impacted by the array geometry and the imaging performance are influenced by the relative imaging position with respect to antennas array. In this paper, the effect of array geometry on CIR system is investigated in detail based on the judgment criteria of the effective rank theory. In course of analyzing of these influences, useful system design guidance about the array geometry is remarked for the CIR system. With the design guidance, the target images are reconstructed based on the Tikhonov regularization algorithm. Simulation results are presented to validate the whole analysis and the efficiency of the design guidance.

  20. 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. PMID:20051345

  1. 2D aperture synthesis for Lamb wave imaging using co-arrays

    NASA Astrophysics Data System (ADS)

    Ambrozinski, Lukasz; Stepinski, Tadeusz; Uhl, Tadeusz

    2014-03-01

    2D ultrasonic arrays in Lamb wave based SHM systems can operate in the phased array (PA) or synthetic focusing (SF) mode. In the real-time PA approach, multiple electronically delayed signals excite transmitting elements to form the desired wave-front, whereas receiving elements are used to sense scattered waves. Due to that, the PA mode requires multi channeled hardware and multiple excitations at numerous azimuths to scan the inspected region of interest. To the contrary, the SF mode, assumes a single element excitation of subsequent transmitters and off-line processing of the acquired data. In the simplest implementation of the SF technique, a single multiplexed input and output channels are required, which results in significant hardware simplification. Performance of a 2D imaging array depends on many parameters, such as, its topology, number of its transducers and their spacing in terms of wavelength as well as the type of weighting function (apodization). Moreover, it is possible to use sparse arrays, which means that not all array elements are used for transmitting and/ or receiving. In this paper the co-array concept is applied to facilitate the 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 co-array is a morphological convolution of the transmit/receive sub-arrays. It can be calculated as the set of sums of the individual elements' locations in the sub-arrays used for imaging. The coarray framework will be presented here using two different array topologies, aID uniform linear array and a cross-shaped array that will result in a square coarray. The approach will be discussed in terms of array patterns and beam patterns of the resulting imaging systems. Both, theoretical and experimental results will be given.

  2. Hybrid µCT-FMT imaging and image analysis

    PubMed Central

    Zafarnia, Sara; Babler, Anne; Jahnen-Dechent, Willi; Lammers, Twan; Lederle, Wiltrud; Kiessling, Fabian

    2015-01-01

    Fluorescence-mediated tomography (FMT) enables longitudinal and quantitative determination of the fluorescence distribution in vivo and can be used to assess the biodistribution of novel probes and to assess disease progression using established molecular probes or reporter genes. The combination with an anatomical modality, e.g., micro computed tomography (µCT), is beneficial for image analysis and for fluorescence reconstruction. We describe a protocol for multimodal µCT-FMT imaging including the image processing steps necessary to extract quantitative measurements. After preparing the mice and performing the imaging, the multimodal data sets are registered. Subsequently, an improved fluorescence reconstruction is performed, which takes into account the shape of the mouse. For quantitative analysis, organ segmentations are generated based on the anatomical data using our interactive segmentation tool. Finally, the biodistribution curves are generated using a batch-processing feature. We show the applicability of the method by assessing the biodistribution of a well-known probe that binds to bones and joints. PMID:26066033

  3. Hybrid PET/MR Imaging and Brain Connectivity.

    PubMed

    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

  4. 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

  5. Phased array beamforming and imaging in composite laminates using guided waves

    NASA Astrophysics Data System (ADS)

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

    2016-04-01

    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 simulated 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 simulated 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.

  6. 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.

  7. 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.

  8. Isolation of disseminated neuroblastoma cells from bone marrow aspirates for pretreatment risk assessment by array comparative genomic hybridization.

    PubMed

    Vandewoestyne, Mado; Kumps, Candy; Swerts, Katrien; Menten, Björn; Lammens, Tim; Philippé, Jan; De Preter, Katleen; Laureys, Geneviève; Van Roy, Nadine; Speleman, Frank; Deforce, Dieter

    2012-03-01

    In neuroblastoma, tumor biopsies are used for prognostic evaluation and risk assessment by molecular genetic analyses such as fluorescence in situ hybridization (FISH) and array comparative genomic hybridization (array CGH). Analysis of primary tumors by array CGH can be hampered by the lack of sufficient tumor cells due to small biopsy size or availability of invaded bone marrow only. Given the importance of accurate assessment of genetic alterations in the diagnostic work-up of patients with neuroblastoma, we evaluated the possibility to analyze bone marrow metastases in patients with disseminated disease. Disseminated neuroblastoma cells were isolated from bone marrow aspirates by using either laser capture microdissection (LCM) or magnetic activated cell sorting (MACS). The array CGH profiles of these isolated metastases were compared to array CGH profiles and/or FISH data of the corresponding primary tumor. Here, we show that the major recurrent DNA copy number alterations detected in primary neuroblastoma tumors (i.e., 1p, 3p and 11q deletion, 17q gain and MYCN amplification) can be detected, with high sensitivity and specificity, in the disseminated neuroblastoma cells isolated from the bone marrow aspirates, using an array platform with high coverage for these regions. Moreover, we demonstrate that for archived material, for example, for retrospective studies, LCM is the method of choice, while for fresh bone marrow aspirates, acquired at the time of diagnosis, MACS is superior. PMID:21484798

  9. 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.

  10. 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

    2016-06-01

    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. PMID:27145724

  11. 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.

  12. Hybrid Imaging for Patient-Specific Dosimetry in Radionuclide Therapy.

    PubMed

    Ljungberg, Michael; Gleisner, Katarina Sjögreen

    2015-01-01

    Radionuclide therapy aims to treat malignant diseases by systemic administration of radiopharmaceuticals, often using carrier molecules such as peptides and antibodies. The radionuclides used emit electrons or alpha particles as a consequence of radioactive decay, thus leading to local energy deposition. Administration to individual patients can be tailored with regards to the risk of toxicity in normal organs by using absorbed dose planning. The scintillation camera, employed in planar imaging or single-photon emission computed tomography (SPECT), generates images of the spatially and temporally varying activity distribution. Recent commercially available combined SPECT and computed tomography (CT) systems have dramatically increased the possibility of performing accurate dose planning by using the CT information in several steps of the dose-planning calculation chain. This paper discusses the dosimetry chain used for individual absorbed-dose planning and highlights the areas where hybrid imaging makes significant contributions. PMID:26854156

  13. Hybrid Imaging for Patient-Specific Dosimetry in Radionuclide Therapy

    PubMed Central

    Ljungberg, Michael; Sjögreen Gleisner, Katarina

    2015-01-01

    Radionuclide therapy aims to treat malignant diseases by systemic administration of radiopharmaceuticals, often using carrier molecules such as peptides and antibodies. The radionuclides used emit electrons or alpha particles as a consequence of radioactive decay, thus leading to local energy deposition. Administration to individual patients can be tailored with regards to the risk of toxicity in normal organs by using absorbed dose planning. The scintillation camera, employed in planar imaging or single-photon emission computed tomography (SPECT), generates images of the spatially and temporally varying activity distribution. Recent commercially available combined SPECT and computed tomography (CT) systems have dramatically increased the possibility of performing accurate dose planning by using the CT information in several steps of the dose-planning calculation chain. This paper discusses the dosimetry chain used for individual absorbed-dose planning and highlights the areas where hybrid imaging makes significant contributions. PMID:26854156

  14. Hybrid backside illuminated CMOS image sensors possessing low crosstalk

    NASA Astrophysics Data System (ADS)

    Ramachandra Rao, Padmakumar; De Munck, Koen; Minoglou, Kyriaki; De Vos, Joeri; Sabuncuoglu, Deniz; De Moor, Piet

    2011-11-01

    Backside illuminated (BSI) hybrid CMOS image sensors possessing excellent spectral response (> 80% between 400nm-800nm) have been previously reported by us. Particularly challenging with BSI imagers is to combine such sensitivity, with low electrical inter-pixel crosstalk (or charge-dispersion). Employing thick bulk silicon (in BSI) to maximize red response results in large crosstalk especially for blue light. In the second generation of these imagers, we undertook the exercise of solving the crosstalk problem by a two-pronged approach: a) an optimized epitaxial substrate that was engineered to maximize the internal electric field b) high aspect ratio trenches (30 μm deep) with carefully tailored sidewall passivation. The results show that the proposed optimizations are effective in curtailing crosstalk without having a major impact on other sensor parameters.

  15. Computation of optimized arrays for 3-D electrical imaging surveys

    NASA Astrophysics Data System (ADS)

    Loke, M. H.; Wilkinson, P. B.; Uhlemann, S. S.; Chambers, J. E.; Oxby, L. S.

    2014-12-01

    3-D electrical resistivity surveys and inversion models are required to accurately resolve structures in areas with very complex geology where 2-D models might suffer from artefacts. Many 3-D surveys use a grid where the number of electrodes along one direction (x) is much greater than in the perpendicular direction (y). Frequently, due to limitations in the number of independent electrodes in the multi-electrode system, the surveys use a roll-along system with a small number of parallel survey lines aligned along the x-direction. The `Compare R' array optimization method previously used for 2-D surveys is adapted for such 3-D surveys. Offset versions of the inline arrays used in 2-D surveys are included in the number of possible arrays (the comprehensive data set) to improve the sensitivity to structures in between the lines. The array geometric factor and its relative error are used to filter out potentially unstable arrays in the construction of the comprehensive data set. Comparisons of the conventional (consisting of dipole-dipole and Wenner-Schlumberger arrays) and optimized arrays are made using a synthetic model and experimental measurements in a tank. The tests show that structures located between the lines are better resolved with the optimized arrays. The optimized arrays also have significantly better depth resolution compared to the conventional arrays.

  16. 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

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

    PubMed

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

    2016-03-01

    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

  18. 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.

  19. 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.

  20. 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).

  1. Imaging Performance of the Si/Ge Hybrid Compton Imager

    SciTech Connect

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

    2005-11-10

    The point spread function (PSF) of a fully-instrumented silicon/germanium Compton telescope has been measured as a function of energy and angle. Overall, the resolution ranged from 3{sup o} to 4{sup o} FWHM over most of the energy range and field of view. The various contributions to the resolution have been quantified. These contributions include the energy uncertainty and position uncertainty of the detector; source energy; Doppler broadening; and the 1/r broadening characteristic of Compton back-projection. Furthermore, a distortion of the PSF is observed for sources imaged off-axis from the detector. These contributions are discussed and compared to theory and simulations.

  2. 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.

  3. High-resolution array imaging using teleseismic converted waves based on adjoint methods

    NASA Astrophysics Data System (ADS)

    Liu, Q.; Chen, C.

    2011-12-01

    Seismic coda waves and converted phases have been used extensively to image detailed subsurface structures underneath seismic arrays, based on methods such as receiver functions, Kirchhoff migration and generalized Radon transform (GRT). Utilizing the same coda and converted waves, we propose to image both discontinuity interfaces and 3D velocity anomalies by combining full numerical simulations of wave propagation with adjoint methods recently adopted in global and regional tomography inversions. The `sensitivities' of these coda/converted waves to density, P and S velocities are calculated based on the interaction of the forward wave field that produces the main P phase, and the adjoint wave field generated by injecting the coda/converted phases at array stations as virtual sources, similar to the computation of isochrons in previous techniques. The density kernels generally highlight discontinuity interfaces and sharp velocity contrasts, while P and S velocity kernels provide hints to the update of volumetric velocity structures. The application of numerical solvers also allows the incorporation of 3D regional tomography models as background velocity models, providing better focusing of velocity anomalies. We show the feasibility of this technique on a synthetic case built based on the imaging geometry for Slave craton in the northwestern Canadian Shield by the POLARIS broadband seismic network. The main challenge of this technique lies in reproducing the forward wave field generated by tele-seismic sources in a limited simulation domain encompassing only local heterogeneous structures underneath array receivers. For simple homogeneous and layer-over-half-space background models, this can be solved by setting the incoming plane waves as initial conditions based on analytical formulae. For more sophisticated background models, a hybrid spectral-element solver is implemented by defining a fictitious boundary encompassing all local heterogeneities within the

  4. Ultra-low dark current InGaAs technology for focal plane arrays for low-light level visible-shortwave infrared imaging

    NASA Astrophysics Data System (ADS)

    Onat, Bora M.; Huang, Wei; Masaun, Navneet; Lange, Michael; Ettenberg, Martin H.; Dries, Christopher

    2007-04-01

    Under the DARPA Photon Counting Arrays (PCAR) program we have investigated technologies to reduce the overall noise level in InGaAs based imagers for identifying a man at 100m under low-light level imaging conditions. We report the results of our experiments comprising of 15 InGaAs wafers that were utilized to investigate lowering dark current in photodiode arrays. As a result of these experiments, we have achieved an ultra low dark current of 2nA/cm2 through technological advances in InGaAs detector design, epitaxial growth, and processing at a temperature of +12.3 degrees C. The InGaAs photodiode array was hybridized to a low noise readout integrated circuit, also developed under this program. The focal plane array (FPA) achieves very high sensitivity in the shortwave infrared bands in addition to the visible response added via substrate removal process post hybridization. Based on our current room-temperature stabilized SWIR camera platform, these imagers enable a full day-night imaging capability and are responsive to currently fielded covert laser designators, illuminators, and rangefinders. In addition, improved haze penetration in the SWIR compared to the visible provides enhanced clarity in the imagery of a scene. In this paper we show the results of our dark current studies as well as FPA characterization of the camera built under this program.

  5. 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.

  6. Silicon PIN diode hybrid arrays for charged particle detection: Building blocks for vertex detectors at the SSC

    SciTech Connect

    Kramer, G.; Gaalema, S.; Shapiro, S.L.; Dunwoodie, W.M.; Arens, J.F.; Jernigan, J.G.

    1989-05-01

    Two-dimensional arrays of solid state detectors have long been used in visible and infrared systems. Hybrid arrays with separately optimized detector and readout substrates have been extensively developed for infrared sensors. The characteristics and use of these infrared readout chips with silicon PIN diode arrays produced by MICRON SEMICONDUCTOR for detecting high-energy particles are reported. Some of these arrays have been produced in formats as large as 512 /times/ 512 pixels; others have been radiation hardened to total dose levels beyond 1 Mrad. Data generation rates of 380 megasamples/second have been achieved. Analog and digital signal transmission and processing techniques have also been developed to accept and reduce these high data rates. 9 refs., 15 figs., 2 tabs.

  7. Experimental verification of SNR and parallel imaging improvements using composite arrays.

    PubMed

    Maunder, Adam; Fallone, B Gino; Daneshmand, Mojgan; De Zanche, Nicola

    2015-02-01

    Composite MRI arrays consist of triplets where two orthogonal upright loops are placed over the same imaging area as a standard surface coil. The optimal height of the upright coils is approximately half the width for the 7 cm coils used in this work. Resistive and magnetic coupling is shown to be negligible within each coil triplet. Experimental evaluation of imaging performance was carried out on a Philips 3 T Achieva scanner using an eight-coil composite array consisting of three surface coils and five upright loops, as well as an array of eight surface coils for comparison. The composite array offers lower overall coupling than the traditional array. The sensitivities of upright coils are complementary to those of the surface coils and therefore provide SNR gains in regions where surface coil sensitivity is low, and additional spatial information for improved parallel imaging performance. Near the surface of the phantom the eight-channel surface coil array provides higher overall SNR than the composite array, but this advantage disappears beyond a depth of approximately one coil diameter, where it is typically more challenging to improve SNR. Furthermore, parallel imaging performance is better with the composite array compared with the surface coil array, especially at high accelerations and in locations deep in the phantom. Composite arrays offer an attractive means of improving imaging performance and channel density without reducing the size, and therefore the loading regime, of surface coil elements. Additional advantages of composite arrays include minimal SNR loss using root-sum-of-squares combination compared with optimal, and the ability to switch from high to low channel density by merely selecting only the surface elements, unlike surface coil arrays, which require additional hardware. PMID:25388793

  8. BI-ground microstrip array coil vs. conventional microstrip array coil for mouse imaging at 7 tesla

    NASA Astrophysics Data System (ADS)

    Hernández, Ricardo; Terrones, M. A. López; Jakob, P. M.

    2012-10-01

    At high field strengths, the need for more efficient high frequency coils has grown. Since the radiation losses and the interaction between coil and sample increase proportionally to field strength, the quality factor (Q) and the sensitivity of the coil decrease as consequence of these negative effects. Since Zhang et al proposed in 2001 a new surface coil based on the microstrip transmission line for high frequency, different Tx-Rx phased arrays based on this concept have been already introduced in animal and whole body systems at high field strengths, each of them with different modifications in order to get better field homogeneity, SNR or isolation between coil elements in the array. All these arrays for animals systems have been built for rat imaging. One of these modifications is called BI-Ground Microstrip Array Coil (BIGMAC). The implementation of a smaller two-channel BIGMAC design for mouse imaging is studied and its performance compared to a two-channel conventional Microstrip array at 7 Tesla, the higher isolation by using BIGMAC elements in comparison with conventional Microstrip elements is shown in this work.

  9. Progress in the development of large-area modular 64 x 64 CdZnTe imaging arrays for nuclear medicine

    SciTech Connect

    Matherson, K.J.; Barber, H.B.; Barrett, H.H.; Eskin, J.D.; Dereniak, E.L.; Marks, D.G.; Woolfenden, J.M.; Young, E.T.; Augustine, F.L.

    1998-06-01

    Previous efforts by this group have demonstrated the potential of hybrid semiconductor detector arrays for use in gamma-ray imaging applications. In this paper, the author describes progress in the development of a prototype imaging system consisting of a 64 x 64-pixel CdZnTe detector array mated to a multiplexer readout circuit that was custom designed for their nuclear medicine application. The detector array consists of a 0.15 cm thick slab of CdZnTe which has a 64 x 64 array of 380 {micro}m square pixel electrodes on one side produced by photolithography; the other side has a continuous electrode biased at {minus}150 V. Electrical connections between the detector electrodes and corresponding multiplexer bump pads are made with indium bump bonds. Although the CdZnTe detector arrays characterized in this paper are room-temperature devices, a slight amount of cooling is necessary to reduce thermally generated dark current in the detectors. Initial tests show that this prototype imager functions well with more than 90% of its pixels operating. The device is an excellent imager; phantom images have a spatial resolution of 1.5 mm, limited by the collimator bore.

  10. 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

  11. Comparative cytogenetic characterization of primary canine melanocytic lesions using array CGH and fluorescence in situ hybridization.

    PubMed

    Poorman, Kelsey; Borst, Luke; Moroff, Scott; Roy, Siddharth; Labelle, Philippe; Motsinger-Reif, Alison; Breen, Matthew

    2015-06-01

    Melanocytic lesions originating from the oral mucosa or cutaneous epithelium are common in the general dog population, with up to 100,000 diagnoses each year in the USA. Oral melanoma is the most frequent canine neoplasm of the oral cavity, exhibiting a highly aggressive course. Cutaneous melanocytomas occur frequently, but rarely develop into a malignant form. Despite the differential prognosis, it has been assumed that subtypes of melanocytic lesions represent the same disease. To address the relative paucity of information about their genomic status, molecular cytogenetic analysis was performed on the three recognized subtypes of canine melanocytic lesions. Using array comparative genomic hybridization (aCGH) analysis, highly aberrant distinct copy number status across the tumor genome for both of the malignant melanoma subtypes was revealed. The most frequent aberrations included gain of dog chromosome (CFA) 13 and 17 and loss of CFA 22. Melanocytomas possessed fewer genome wide aberrations, yet showed a recurrent gain of CFA 20q15.3-17. A distinctive copy number profile, evident only in oral melanomas, displayed a sigmoidal pattern of copy number loss followed immediately by a gain, around CFA 30q14. Moreover, when assessed by fluorescence in situ hybridization (FISH), copy number aberrations of targeted genes, such as gain of c-MYC (80 % of cases) and loss of CDKN2A (68 % of cases), were observed. This study suggests that in concordance with what is known for human melanomas, canine melanomas of the oral mucosa and cutaneous epithelium are discrete and initiated by different molecular pathways. PMID:25511566

  12. Array Comparative Genomic Hybridization (aCGH) Analysis in Patients with Anophthalmia, Microphthalmia and Coloboma

    PubMed Central

    Raca, Gordana; Jackson, Craig A.; Kucinskas, Laimutis; Warman, Berta; Shieh, Joseph T. C.; Schneider, Adele; Bardakjian, Tanya M.; Schimmenti, Lisa A.

    2014-01-01

    Purpose The goal of our study was to determine whether genomic copy number abnormalities (deletions and duplications) affecting genes involved in eye development contribute to the etiology of anophthalmia, microphthalmia and coloboma. Methods The affected individuals were tested for deletions and duplications in genomic DNA using 2 million probe (HD2) comparative genomic hybridization arrays (aCGH) from Roche-NimbleGen. Results Array analysis of 32 patients detected one case with a deletion encompassing the Renal-coloboma syndrome associated gene PAX2. Non-polymorphic copy number changes were also observed at several candidate chromosomal regions, including 6p12.3, 8q23.1q23.2, 13q31.3, 15q11.2q13.1, 16p13.13 and 20q13.13. Conclusions This study identified the first patient with the typical phenotype of the Renal-coloboma syndrome caused by a submicroscopic deletion of the coding region of the PAX2 gene. The finding suggests that PAX2 deletion testing should be performed in addition to gene sequencing as a part of molecular evaluation for the Renal-coloboma syndrome. aCGH testing of 32 affected individual showed that genomic deletions and duplications are not a common cause of non-syndromic anophthalmia, microphthalmia and/or coloboma, but undoubtedly contribute to the etiology of these eye anomalies. aCGH testing therefore represents an important and valuable addition to candidate gene sequencing in research and diagnostics of ocular birth defects. PMID:21285886

  13. A Gold Sensors Array for Imaging The Real Tissue Phantom in Electrical Impedance Tomography

    NASA Astrophysics Data System (ADS)

    Kanti Bera, Tushar; Nagaraju, J.

    2015-02-01

    Surface electrodes in Electrical Impedance Tomography (EIT) phantoms usually reduce the SNR of the boundary potential data due to their design and development errors. A novel gold sensors array with high geometric precision is developed for EIT phantoms to improve the resistivity image quality. Gold thin films are deposited on a flexible FR4 sheet using electro-deposition process to make a sixteen electrode array with electrodes of identical geometry. A real tissue gold electrode phantom is developed with chicken tissue paste and the fat cylinders as the inhomogeneity. Boundary data are collected using a USB based high speed data acquisition system in a LabVIEW platform for different inhomogeneity positions. Resistivity images are reconstructed using EIDORS and compared with identical stainless steel electrode systems. Image contrast parameters are calculated from the resistivity matrix and the reconstructed images are evaluated for both the phantoms. Image contrast and image resolution of resistivity images are improved with gold electrode array.

  14. 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.

  15. An optimized hybrid encode based compression algorithm for hyperspectral image

    NASA Astrophysics Data System (ADS)

    Wang, Cheng; Miao, Zhuang; Feng, Weiyi; He, Weiji; Chen, Qian; Gu, Guohua

    2013-12-01

    Compression is a kernel procedure in hyperspectral image processing due to its massive data which will bring great difficulty in date storage and transmission. In this paper, a novel hyperspectral compression algorithm based on hybrid encoding which combines with the methods of the band optimized grouping and the wavelet transform is proposed. Given the characteristic of correlation coefficients between adjacent spectral bands, an optimized band grouping and reference frame selection method is first utilized to group bands adaptively. Then according to the band number of each group, the redundancy in the spatial and spectral domain is removed through the spatial domain entropy coding and the minimum residual based linear prediction method. Thus, embedded code streams are obtained by encoding the residual images using the improved embedded zerotree wavelet based SPIHT encode method. In the experments, hyperspectral images collected by the Airborne Visible/ Infrared Imaging Spectrometer (AVIRIS) were used to validate the performance of the proposed algorithm. The results show that the proposed approach achieves a good performance in reconstructed image quality and computation complexity.The average peak signal to noise ratio (PSNR) is increased by 0.21~0.81dB compared with other off-the-shelf algorithms under the same compression ratio.

  16. 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.

  17. 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.

  18. 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.

  19. Imaging slow earthquakes in Cascadia using seismic arrays

    NASA Astrophysics Data System (ADS)

    Ghosh, Abhijit

    Slow earthquakes have been observed in major plate boundaries worldwide, and accommodate a significant part of the plate motion through slow slip in the transition zone of the faults. They occur down-dip of the locked zone, where large damaging fast earthquakes nucleate. The physical processes that control slow quakes, however, remain enigmatic. To understand slow earthquakes, I study non-volcanic tremor, a form of seismic radiation associated with slow quakes. It is challenging to detect and locate tremor due to its lack of clear impulsive arrivals. I develop a new beam-backprojection technique to image slow earthquakes in high resolution by detecting and precisely locating tremor using small aperture seismic arrays. This technique can detect more duration of tremor, gives high resolution in tremor locations compared to a conventional envelope cross-correlation method, and also resolve tremor depth. I apply this technique in Cascadia, and show that the majority of tremor is occurring near the plate interface suggesting that they are possibly a result of shear slip on the subduction fault. Transition zone producing tremor appears to be fairly heterogeneous. Three patches down-dip of the transition zone produce majority of the tremor during small to moderate-sized tremor episodes. The patches repeat 10--15 times in 15 months. On the other hand, several up-dip patches are responsible for most of the tremor activity during large slow quakes. Moreover, I find that tremor behavior changes dramatically over different time scales. Over the time scale of several minutes, tremor propagates rapidly sub-parallel to the slip direction of the subduction zone at a velocity of ˜100 km/hr. This quasi-continuous streaking of tremor produces slip-parallel tremor bands over the time scale of several hours. Tremor bands migrate along-strike resulting in the slow rupture propagation at an average velocity of ˜8 km/day. Along-strike slow rupture propagation velocity during a large

  20. 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

  1. 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.

  2. 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.

  3. 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

  4. 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.

  5. Hybrid-modality high-resolution imaging: for diagnostic biomedical imaging and sensing for disease diagnosis

    NASA Astrophysics Data System (ADS)

    Murukeshan, Vadakke M.; Hoong Ta, Lim

    2014-11-01

    Medical diagnostics in the recent past has seen the challenging trend to come up with dual and multi-modality imaging for implementing better diagnostic procedures. The changes in tissues in the early disease stages are often subtle and can occur beneath the tissue surface. In most of these cases, conventional types of medical imaging using optics may not be able to detect these changes easily due to its penetration depth of the orders of 1 mm. Each imaging modality has its own advantages and limitations, and the use of a single modality is not suitable for every diagnostic applications. Therefore the need for multi or hybrid-modality imaging arises. Combining more than one imaging modalities overcomes the limitation of individual imaging method and integrates the respective advantages into a single setting. In this context, this paper will be focusing on the research and development of two multi-modality imaging platforms. The first platform combines ultrasound and photoacoustic imaging for diagnostic applications in the eye. The second platform consists of optical hyperspectral and photoacoustic imaging for diagnostic applications in the colon. Photoacoustic imaging is used as one of the modalities in both platforms as it can offer deeper penetration depth compared to optical imaging. The optical engineering and research challenges in developing the dual/multi-modality platforms will be discussed, followed by initial results validating the proposed scheme. The proposed schemes offer high spatial and spectral resolution imaging and sensing, and is expected to offer potential biomedical imaging solutions in the near future.

  6. Homozygous losses detected by array comparative genomic hybridization in multiplex urothelial carcinomas of the bladder.

    PubMed

    Beothe, Tamas; Zubakov, Dmitry; Kovacs, Gyula

    2015-09-01

    Urothelial carcinomas (UCs) may present at first as a solitary or multifocal neoplasm. We applied high resolution array comparative genomic hybridization to 24 solitary and 32 multiplex UCs and used the hidden Markov model algorithm to identify the copy number changes at the probe level. Copy number losses and homozygous deletions at the chromosome 9p region affecting the CDKN2A and MTAP genes were the most frequent alterations in both groups of tumors. We have delineated two new tumor suppressor gene regions at chromosome 9p that harbor the PTPRD and BNC2 genes. Copy number losses at chromosomal regions 2q, 8p, and 18p occurred preferentially in solitary UCs, whereas multiplex UCs displayed loss of large chromosomal regions at 9q, 10q, 11q, 18q, and 21q. Homozygous deletions harboring loci of cell adhesion genes such as claudins, desmocollins, and desmogleins were seen exclusively in multiplex UCs. Amplifications occurred only in invasive G3 UCs irrespective of staging. Our study suggests that solitary and multiplex UCs may have divergent genetic pathways. The biallelic inactivation of cellular adhesion genes by homozygous deletions in multiplex UCs may explain the frequent intravesical spreading of tumor cells. . PMID:26235493

  7. Making hybrid [n]-rotaxanes as supramolecular arrays of molecular electron spin qubits

    NASA Astrophysics Data System (ADS)

    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.

  8. Genomic copy number alterations in 33 malignant peritoneal mesothelioma analyzed by comparative genomic hybridization array.

    PubMed

    Chirac, Pierre; Maillet, Denis; Leprêtre, Frédéric; Isaac, Sylvie; Glehen, Olivier; Figeac, Martin; Villeneuve, Laurent; Péron, Julien; Gibson, Fernando; Galateau-Sallé, Françoise; Gilly, François-Noël; Brevet, Marie

    2016-09-01

    Malignant peritoneal mesotheliomas (MPM) are rare, accounting for approximately 8% of cases of mesothelioma in France. We performed comparative genomic hybridization (CGH) on frozen MPM samples using the Agilent Human Genome CGH 180 K array. Samples were taken from a total of 33 French patients, comprising 20 men and 13 women with a mean (range) age of 58.4 (17-76) years. Asbestos exposure was reported in 8 patients (24.2%). Median (range) overall survival (OS) was 39 (0-119) months. CGH analysis demonstrated the presence of chromosomal instability in patients with MPM, with a genomic pattern that was similar to that described for pleural mesothelioma, including the loss of chromosomal regions 3p21, 9p21, and 22q12. In addition, novel genomic copy number alterations were identified, including the 15q26.2 region and the 8p11.22 region. Median OS was associated with a low peritoneal cancer index (P=.011), epithelioid subtype (P=.038), and a low number of genomic aberrations (P=.015), all of which constitute good prognostic factors for MPM. Our results provide new insights into the genetic and genomic background of MPM. Although pleural and peritoneal mesotheliomas have different risk factors, different therapeutics, and different prognosis; these data provide support to combine pleural and peritoneal mesothelioma in same clinical assays. PMID:27184482

  9. SiGe Integrated Circuit/SQUID Hybrid Cryogenic Multiplexer for Superconducting Bolometer Array

    NASA Astrophysics Data System (ADS)

    Prêle, D.; Voisin, F.; Oger, R.; Chapron, C.; Bréelle, E.; Piat, M.

    2009-12-01

    The development of large superconducting bolometer (Transition Edge Sensor: TES) arrays requires ultra low noise amplification and multiplexing electronics. The use of a first transducer stage such as a SQUID (Superconducting QUantum Interference Device) allows ultimate performance in terms of noise. However, the linearization of the SQUID characteristic requires low noise amplification. Furthermore, to realize a time domain multiplexer with SQUIDs, switched biasing is also needed. We have designed an Integrated Circuit (IC) in standard BiCMOS SiGe technology for the readout and the control of a SQUID multiplexer. It includes a low noise amplifier with multiplexed inputs, switched current sources for SQUIDs, and digital circuit for the addressing with only one room temperature clock signal. We have successfully tested this integrated circuit down to 2 K. To validate the operation of a SQUID multiplexer controlled by this SiGe cryogenic IC, we have developed a 2×2 SQUID hybrid demonstrator. It consists of four commercial SQUIDs connected to a SiGe IC.

  10. Making hybrid [n]-rotaxanes as supramolecular arrays of molecular electron spin qubits.

    PubMed

    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(O2C(t)Bu)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

  11. 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

  12. 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.

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

    DOE PAGESBeta

    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. 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

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

    PubMed

    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

  15. 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

  16. Multi-Channel Microstrip Transceiver Arrays Using Harmonics for High Field MR Imaging in Humans

    PubMed Central

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

    2012-01-01

    RF transceiver array design using primary and higher order harmonics for in-vivo parallel MR imaging 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. PMID:21878410

  17. 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.

  18. Classification of tea category using a portable electronic nose based on an odor imaging sensor array.

    PubMed

    Chen, Quansheng; Liu, Aiping; Zhao, Jiewen; Ouyang, Qin

    2013-10-01

    A developed portable electronic nose (E-nose) based on an odor imaging sensor array was successfully used for classification of three different fermentation degrees of tea (i.e., green tea, black tea, and Oolong tea). The odor imaging sensor array was fabricated by printing nine dyes, including porphyrin and metalloporphyrins, on the hydrophobic porous membrane. A color change profile for each sample was obtained by differentiating the image of sensor array before and after exposure to tea's volatile organic compounds (VOCs). Multivariate analysis was used for the classification of tea categories, and linear discriminant analysis (LDA) achieved 100% classification rate by leave-one-out cross-validation (LOOCV). This study demonstrates that the E-nose based on odor imaging sensor array has a high potential in the classification of tea category according to different fermentation degrees. PMID:23810847

  19. 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.

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

    NASA Astrophysics Data System (ADS)

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

    2009-12-01

    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 60 360×33.5 μm2 DROIDs in a 3×20 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 ˜35 μm 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.

  1. Realization of integral 3-dimensional image using fabricated tunable liquid lens array

    NASA Astrophysics Data System (ADS)

    Lee, Muyoung; Kim, Junoh; Kim, Cheol Joong; Lee, Jin Su; Won, Yong Hyub

    2015-03-01

    Electrowetting has been widely studied for various optical applications such as optical switch, sensor, prism, and display. In this study, vari-focal liquid lens array is developed using electrowetting principle to construct integral 3-dimensional imaging. The electrowetting principle that changes the surface tension by applying voltage has several advantages to realize active optical device such as fast response time, low electrical consumption, and no mechanical moving parts. Two immiscible liquids that are water and oil are used for forming lens. By applying a voltage to the water, the focal length of the lens could be tuned as changing contact angle of water. The fabricated electrowetting vari-focal liquid lens array has 1mm diameter spherical lens shape that has 1.6mm distance between each lens. The number of lenses on the panel is 23x23 and the focal length of the lens array is simultaneously tuned from -125 to 110 diopters depending on the applied voltage. The fabricated lens array is implemented to integral 3-dimensional imaging. A 3D object is reconstructed by fabricated liquid lens array with 23x23 elemental images that are generated by 3D max tools. When liquid lens array is tuned as convex state. From vari-focal liquid lens array implemented integral imaging system, we expect that depth enhanced integral imaging can be realized in the near future.

  2. High frame rate photoacoustic imaging using multiple wave-length LED array light source

    NASA Astrophysics Data System (ADS)

    Agano, Toshitaka; Sato, Naoto; Nakatsuka, Hitoshi; Kitagawa, Kazuo; Hanaoka, Takamitsu; Morisono, Koji; Shigeta, Yusuke; Tanaka, Chizuyo

    2016-03-01

    We have successfully imaged photoacoustic differences of light absorbance between two images acquired by different wave-length LED array light source. Compared to photoacoustic imaging system using conventional solid-state laser light source, LED light source can be driven at higher frequency pulses, so we were able to get the subtraction image at higher frame rate that calculated from two images which were captured at each wave-length LED light pulse timing. We developed LED array light source which is composed to have two different wave-length chips, so each wave-length light pulse can be controlled and emitted freely. Thus LED array light source can be composed as multiple selectable wavelength more than two, and a various combination of subtraction image may become available at high frame rate.

  3. 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. PMID:26369158

  4. A hybrid strategy for correcting geometric distortion in echo-planar images.

    PubMed

    Gelman, Neil; Silavi, Ally; Anazodo, Udunna

    2014-06-01

    A hybrid strategy for geometric distortion correction of echo-planar images is demonstrated. This procedure utilizes standard field mapping for signal displacement correction and the so-called reverse gradient acquisition for signal intensity correction. (The term reverse gradient refers to an acquisition of two sets of echo-planar images with phase encoding gradients of opposite polarity.) The hybrid strategy is applied to human brain echo-planar images acquired with and without diffusion-weighting. A comparison of the hybrid distortion corrected images to those corrected with standard field mapping only demonstrates much better performance of the hybrid method. A variant of the hybrid method is also demonstrated which requires the acquisition of only one pair of opposite polarity images within a set of images. PMID:24650682

  5. Dual array 3D electron cyclotron emission imaging at ASDEX Upgrade

    SciTech Connect

    Classen, I. G. J. Bogomolov, A. V.; Domier, C. W.; Luhmann, N. C.; Suttrop, W.; Boom, J. E.; Tobias, B. J.; Donné, A. J. H.

    2014-11-15

    In a major upgrade, the (2D) electron cyclotron emission imaging diagnostic (ECEI) at ASDEX Upgrade has been equipped with a second detector array, observing a different toroidal position in the plasma, to enable quasi-3D measurements of the electron temperature. The new system will measure a total of 288 channels, in two 2D arrays, toroidally separated by 40 cm. The two detector arrays observe the plasma through the same vacuum window, both under a slight toroidal angle. The majority of the field lines are observed by both arrays simultaneously, thereby enabling a direct measurement of the 3D properties of plasma instabilities like edge localized mode filaments.

  6. Wearable Ultrasound Array for Point-of-Care Imaging and Patient Monitoring.

    PubMed

    Mierzwa, Andrzej P; Huang, Sean P; Nguyen, Kristen T; Culjat, Martin O; Singh, Rahul S

    2016-01-01

    A versatile, flexible piezoceramic array has been developed for a variety of ultrasound applications. The transducer can be configured as a linear or curvilinear transducer array, or mounted directly onto the body as a patch or wearable device. Results using a prototype 16-element array demonstrated equivalence to commercial linear array probes in accuracy of vessel diameter measurements in vascular phantoms. The ability to view needle insertion for peripherally inserted central catheter (PICC) procedures was also demonstrated. Opportunities for wearable ultrasound devices include point-of-care imaging, combat casualty care, ultrasound therapy, patient monitoring, and personal health. PMID:27046585

  7. Dual array 3D electron cyclotron emission imaging at ASDEX Upgrade.

    PubMed

    Classen, I G J; Domier, C W; Luhmann, N C; Bogomolov, A V; Suttrop, W; Boom, J E; Tobias, B J; Donné, A J H

    2014-11-01

    In a major upgrade, the (2D) electron cyclotron emission imaging diagnostic (ECEI) at ASDEX Upgrade has been equipped with a second detector array, observing a different toroidal position in the plasma, to enable quasi-3D measurements of the electron temperature. The new system will measure a total of 288 channels, in two 2D arrays, toroidally separated by 40 cm. The two detector arrays observe the plasma through the same vacuum window, both under a slight toroidal angle. The majority of the field lines are observed by both arrays simultaneously, thereby enabling a direct measurement of the 3D properties of plasma instabilities like edge localized mode filaments. PMID:25430246

  8. Fast photo-acoustic imaging based on multi-element linear transducer array

    NASA Astrophysics Data System (ADS)

    Yin, Bangzheng; Xing, Da; Yang, Diwu; Tan, Yi; Chen, Qun

    2005-04-01

    Photoacoustic imaging combines the contrast advantage of pure optical imaging and the resolution advantage of pure ultrasonic imaging. It has become a popular research subject at present. A fast photoacoustic imaging system based on multi-element linear transducer array and phase-controlled focus method was developed and tested on phantoms and tissues. A Q switched Nd:YAG laser operating at 532nm was used in our experiment as thermal source. The multi-element linear transducer array consists of 320 elements. By phase-controlled focus method, 64 signals, one of which gathered by 11-group element, make up of an image. Experiment results can map the distribution of the optical absorption correctly. The same transducer array also can operate as a conventional phase array and produced ultrasound imaging. Compared to other existing technology and algorithm, the PA imaging based on transducer array was characterize by speediness and convenience. It can provide a new approach for tissue functional imaging in vivo, and may have potentials in developing into an appliance for clinic diagnosis.

  9. 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

    2014-04-01

    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. PMID:24562374

  10. 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.

  11. An improved solution for integrated array optics in quasi-optical mm and submm receivers: The hybrid antenna

    SciTech Connect

    Buettgenback, T.H. . Div. of Physics)

    1993-10-01

    The hybrid antenna discussed here is defined as a dielectric lens-antenna as a special case of an extended hemispherical 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 hemispherical 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 [+-] 6)% for a diffraction limited beam with sidelobes below [minus]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.

  12. 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.

  13. A Mobile Ferromagnetic Shape Detection Sensor Using a Hall Sensor Array and Magnetic Imaging

    PubMed Central

    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. PMID:22346653

  14. Array Comparative Genomic Hybridization in Ulcerative Colitis Neoplasia: Single Non-Dysplastic Biopsies Distinguish Progressors from Non-Progressors

    PubMed Central

    Bronner, Mary P.; Skacel, Marek; Crispin, David A.; Hoff, Peter D.; Emond, Mary J.; Lai, Lisa A.; Tubbs, Raymond R.; Rabinovitch, Peter S.; Brentnall, Teresa A.

    2010-01-01

    Approximately 10% of ulcerative colitis patients develop colorectal neoplasia. At present, identification of this subset is markedly limited and necessitates lifelong colonoscopic surveillance for the entire ulcerative colitis population. Better risk markers are needed to focus surveillance onto the patients most likely to benefit. Using array-based comparative genomic hybridization, we analyzed single, non-dysplastic biopsies from three patient groups: ulcerative colitis progressors (n=9) with cancer or high-grade dysplasia at a mean distance of 18 cm from the analyzed site; ulcerative colitis nonprogressors (n=8) without dysplasia during long-term surveillance; and non-ulcerative colitis normal controls (n=2). Genomic DNA from fresh colonic epithelium purified from stroma was hybridized to 287 (low-density) and 4,342 (higher-density) feature bacterial artificial chromosome arrays. Sample-to-reference fluorescence ratios were calculated for individual chromosomal targets and globally across the genome. The low-density arrays yielded pronounced genomic gains and losses in 3 of 9 (33%) ulcerative colitis progressors but in none of the 10 control patients. Identical DNA samples analyzed on the higher density arrays, using a combination of global and individual high variance assessments, distinguished all 9 progressors from all 10 controls. These data confirm that genomic alterations in ulcerative colitis progressors are widespread, even involving single non-dysplastic biopsies far distant from neoplasia. They therefore show promise toward eliminating full colonoscopic surveillance with extensive biopsy sampling in the majority of ulcerative colitis patients. PMID:20802465

  15. Fast and enhanced broadband photoresponse of a ZnO nanowire array/reduced graphene oxide film hybrid photodetector from the visible to the near-infrared range.

    PubMed

    Liu, Hao; Sun, Qi; Xing, Jie; Zheng, Zhiyuan; Zhang, Zhili; Lü, Zhiqing; Zhao, Kun

    2015-04-01

    In the present work, a ZnO nanowire array/reduced graphene oxide film hybrid nanostructure was realized, and the photovoltaic responses from the visible to the near-infrared range were investigated. Compared with the pure ZnO nanowire array and rGO thin film, the hybrid composite exhibited a fast and greatly enhanced broadband photovoltaic response that resulted from the formation of interfacial Schottky junctions between ZnO and rGO. PMID:25768384

  16. 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.

  17. 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.

  18. Identification of Genomic Alterations in Pancreatic Cancer Using Array-Based Comparative Genomic Hybridization

    PubMed Central

    Liang, Jian-Wei; Shi, Zhi-Zhou; Shen, Tian-Yun; Che, Xu; Wang, Zheng; Shi, Su-Sheng; Xu, Xin; Cai, Yan; Zhao, Ping; Wang, Cheng-Feng; Zhou, Zhi-Xiang; Wang, Ming-Rong

    2014-01-01

    Background Genomic aberration is a common feature of human cancers and also is one of the basic mechanisms that lead to overexpression of oncogenes and underexpression of tumor suppressor genes. Our study aims to identify frequent genomic changes in pancreatic cancer. Materials and Methods We used array comparative genomic hybridization (array CGH) to identify recurrent genomic alterations and validated the protein expression of selected genes by immunohistochemistry. Results Sixteen gains and thirty-two losses occurred in more than 30% and 60% of the tumors, respectively. High-level amplifications at 7q21.3–q22.1 and 19q13.2 and homozygous deletions at 1p33–p32.3, 1p22.1, 1q22, 3q27.2, 6p22.3, 6p21.31, 12q13.2, 17p13.2, 17q21.31 and 22q13.1 were identified. Especially, amplification of AKT2 was detected in two carcinomas and homozygous deletion of CDKN2C in other two cases. In 15 independent validation samples, we found that AKT2 (19q13.2) and MCM7 (7q22.1) were amplified in 6 and 9 cases, and CAMTA2 (17p13.2) and PFN1 (17p13.2) were homozygously deleted in 3 and 1 cases. AKT2 and MCM7 were overexpressed, and CAMTA2 and PFN1 were underexpressed in pancreatic cancer tissues than in morphologically normal operative margin tissues. Both GISTIC and Genomic Workbench software identified 22q13.1 containing APOBEC3A and APOBEC3B as the only homozygous deletion region. And the expression levels of APOBEC3A and APOBEC3B were significantly lower in tumor tissues than in morphologically normal operative margin tissues. Further validation showed that overexpression of PSCA was significantly associated with lymph node metastasis, and overexpression of HMGA2 was significantly associated with invasive depth of pancreatic cancer. Conclusion These recurrent genomic changes may be useful for revealing the mechanism of pancreatic carcinogenesis and providing candidate biomarkers. PMID:25502777

  19. 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.

  20. A Novel ASI Array for Redline Auroral Imaging across Northern Canada

    NASA Astrophysics Data System (ADS)

    Unick, C.; Donovan, E.; Spanswick, E.; Jackel, B. J.; Groves, P.; McGuffin, N.; Chaddock, D.; James, S.; Lambrinoudis, C.

    2014-12-01

    The redline aurora is a tracer of magnetospheric structure and dynamics. From drifting polar cap patches to bursty bulk flows (BBFs) in the mid-tail, the redline aurora provides key information about system-level dynamics and coupling between plasma regimes. In this paper we present a new all-sky imager (ASI) array that measures the 6300Å emission line from neutral Oxygen in the aurora. The array coverage extends from south of Gillam, Manitoba, to north of Resolute Bay, Nunavut, and to the west of Fort Smith, NWT, and the array is synchronized at 3 second cadence in the same manner that the THEMIS ASI array is. The camera has superior resolution and noise performance compared to previous generations of auroral cameras. The imager employs only one filter and thus monitors one auroral line throughout the array simultaneously and continuously (at high cadence). The new design has better immunity to internal scatter and produces images of faint aurora when the moon is in the field of view, which corrects another deficiency of some currently deployed auroral imager systems. We present the new instrument design, test data from the commissioning phase of the array deployment, and thoughts on the scientific potential of the array.

  1. Mid-Range Coil Array for Magnetic Resonance Imaging of Small Animals

    NASA Astrophysics Data System (ADS)

    Solis, S. E.; Tomasi, D.; Rodríguez, A. O.

    2008-08-01

    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.

  2. 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.

  3. 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.

  4. Reconstruction of quasimonochromatic images for multispectral x-ray imaging with a pinhole array and a flat Bragg mirror

    SciTech Connect

    Izumi, N.; Barbee, T. W.; Koch, J. A.; Mancini, R. C.; Welser, L. A.

    2006-08-15

    We have developed a software package for reconstruction of quasimonochromatic images from a multiple monochromatic x-ray imager for inertial confinement fusion implosions. The instrument consists of a pinhole array, a multilayer Bragg mirror, and an image detector. The pinhole array projects hundreds of images onto the detector after reflection off the multilayer Bragg mirror, which introduces spectral dispersion along the reflection axis. The quasimonochromatic images of line emissions and continuum emissions can be used for measurement of temperature and density maps of implosion plasmas. In this article, we describe a computer-aided processing technique for systematic reconstruction of quasimonochromatic images from raw data. This technique provides flexible spectral bandwidth selection and allows systematic subtraction of continuum emission from line emission images.

  5. A decoupled coil detector array for fast image acquisition in magnetic resonance imaging.

    PubMed

    Kwiat, D; Einav, S; Navon, G

    1991-01-01

    A method for magnetic resonance imaging (MRI) is investigated here, whereby an object is put under a homogeneous magnetic field, and the image is obtained by applying inverse source procedures to the data collected in an array of coil detectors surrounding the object. The induced current in each coil due to the precession of the magnetic dipole in each voxel depends on the characteristics of both the magnetic dipole frequency and strength, together with its distance from the coil, the coil direction in space, and the electrical properties of the coils. By calculating the induced current signals over an array of coil detectors, a relationship is established between the set of signals and the structure of the body under investigation. The linear relation can then be represented in matrix notation, and inversion of this matrix will produce an image of the body. Important problems which must be considered in the proposed method are signal-to-noise ratio (SNR) and coupling between adjacent coils. Solutions to these problems will provide a new method for obtaining an instantaneous image by NMR, with no need for gradient switching for encoding. A general algorithm for decoupling of the coils is presented and fast sampling of the signal, instead of filtering, is used in order to reduce both noise and numerical roundoff errors at the same time. Sensitivity considerations are made with respect to the number of coils that is required and its connection with coil radius and SNR. A computer simulation demonstrates the feasibility of this new modality. Based on the solutions presented here for the problems involved in the use of a large number of coils for a simultaneous recording of the signal, an improved method of multicoil recording is suggested, whereby it is combined with the conventional zeugmatographic method with read and phase gradients, to result in a novel method of magnetic resonance imaging. In the combined method, there are no phase-encoding gradients. Only a

  6. 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.

  7. High-resolution vascular tissue characterization in mice using 55 MHz ultrasound hybrid imaging

    PubMed Central

    Mahmoud, Ahmed M.; Sandoval, Cesar; Teng, Bunyen; Schnermann, Jurgen B.; Martin, Karen H.; Mustafa, S. Jamal; Mukdadi, Osama M.

    2012-01-01

    Ultrasound and Duplex ultrasonography in particular are routinely used to diagnose cardiovascular disease (CVD), which is the leading cause of morbidity and mortality worldwide. However, these techniques may not be able to characterize vascular tissue compositional changes due to CVD. This work describes an ultrasound-based hybrid imaging technique that can be used for vascular tissue characterization and the diagnosis of atherosclerosis. Ultrasound radiofrequency (RF) data were acquired and processed in time, frequency, and wavelet domains to extract six parameters including time integrated backscatter (TIB), time variance (Tvar), time entropy (TE), frequency integrated backscatter (FIB), wavelet root mean square value (Wrms), and wavelet integrated backscatter (WIB). Each parameter was used to reconstruct an image co-registered to morphological B-scan. The combined set of hybrid images were used to characterize vascular tissue in vitro and in vivo using three mouse models including control (C57BL/6), and atherosclerotic apolipoprotein E-knockout (APOE-KO) and APOE/A1 adenosine receptor double knockout (DKO) mice. The technique was tested using high-frequency ultrasound including single-element (center frequency = 55 MHz) and commercial array (center frequency = 40 MHz) systems providing superior spatial resolutions of 24 μm and 40 μm, respectively. Atherosclerotic vascular lesions in the APOE-KO mouse exhibited the highest values (contrast) of −10.11 ± 1.92 dB, −12.13 ± 2.13 dB, −7.54 ± 1.45 dB, −5.10 ± 1.06 dB, −5.25 ± 0.94 dB, and −10.23 ± 2.12 dB in TIB, Tvar, TE, FIB, Wrms, WIB hybrid images (n = 10, p < 0.05), respectively. Control segments of normal vascular tissue showed the lowest values of −20.20 ± 2.71 dB, −22.54 ± 4.54 dB, −14.94 ± 2.05 dB, −9.64 ± 1.34 dB, −10.20 ± 1.27 dB, and −19.36 ± 3.24 dB in same hybrid images (n = 6, p < 0.05). Results from both histology and optical images showed good agreement with

  8. 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. PMID:27047730

  9. Three-dimensional near-field MIMO array imaging using range migration techniques.

    PubMed

    Zhuge, Xiaodong; Yarovoy, Alexander G

    2012-06-01

    This paper presents a 3-D near-field imaging algorithm that is formulated for 2-D wideband multiple-input-multiple-output (MIMO) imaging array topology. The proposed MIMO range migration technique performs the image reconstruction procedure in the frequency-wavenumber domain. The algorithm is able to completely compensate the curvature of the wavefront in the near-field through a specifically defined interpolation process and provides extremely high computational efficiency by the application of the fast Fourier transform. The implementation aspects of the algorithm and the sampling criteria of a MIMO aperture are discussed. The image reconstruction performance and computational efficiency of the algorithm are demonstrated both with numerical simulations and measurements using 2-D MIMO arrays. Real-time 3-D near-field imaging can be achieved with a real-aperture array by applying the proposed MIMO range migration techniques. PMID:22345541

  10. System design of submillimeter-wave imaging array SISCAM

    NASA Astrophysics Data System (ADS)

    Matsuo, H.; Hibi, Y.; Nagata, H.; Nakahashi, M.; Murakoshi, Y.; Arai, H.; Ariyoshi, S.; Otani, C.; Ikeda, H.; Fujiwara, M.

    2008-07-01

    Developments on large format array of superconducting tunnel junction detectors are discussed and recent activities in readout electronics developments and focal plane optics designs are presented. We have been working on submillimeter-wave SIS photon detectors at 650 GHz using niobium tunnel junctions, which have high sensitivity, large dynamic range and fast response. Here we discuss on an implementation plan of large format array with cryogenic readout electronics and compact focal plane optics design. GaAs-JFETs operate at less than 1 K with low noise, low power dissipation and fast response. We have demonstrated operation of cryogenic integrating amplifiers and digital electronics for SIS photon detectors with multiplexed readout. Combined with compact focal plane optics, we now have a conceptual design of large format array of SIS photon detectors in submillimeter-wave. Further development to realize higher sensitivity superconducting tunnel junction detectors with extremely low leakage current are foreseen.

  11. Silicon Geiger-mode avalanche photodiode arrays for photon-starved imaging

    NASA Astrophysics Data System (ADS)

    Aull, Brian F.

    2015-05-01

    Geiger-mode avalanche photodiodes (GMAPDs) are capable of detecting single photons. They can be operated to directly trigger all-digital circuits, so that detection events are digitally counted or time stamped in each pixel. An imager based on an array of GMAPDs therefore has zero readout noise, enabling quantum-limited sensitivity for photon-starved imaging applications. In this review, we discuss devices developed for 3D imaging, wavefront sensing, and passive imaging.

  12. 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.

  13. Three-dimensional scene reconstruction by using lenslet array model in computational integral imaging

    NASA Astrophysics Data System (ADS)

    Huang, YuSheng; Xia, Jun; Yin, HanChun

    2009-11-01

    Integral imaging is a promising technique for both 3-D scene capturing and reconstruction. Recently, computational simulation has been used to generate the free view of reconstructed scenes without optical devices, which can easily overcome image quality degradation due to the physical limitations of optical devices. In the reconstruction process of integral imaging, current researches focus on the pinhole array model which regards lenslet array as pinhole array for simplicity. But in fact, the optical characteristics of the lenslet such as the focal length, the aperture size of the lenslet, and so on, have significant impact on the reconstructed 3-D scene. In this paper, we proposed a lenslet array model in computational integral imaging. The elemental images were picked up by using a well developed computer graphics programming library OpenGL. And then 3-D scene was reconstructed by an ideal diffraction-limited integral imaging model which taken into account of the effect of the focal length and the aperture size. We presented some simulations and evaluated the image quality by the peak-to-peak signal-to-noise ratio (PSNR). Experimental results show that the proposed lenslet array model increase the depth of field.

  14. 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.

  15. 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.

  16. Genomic Characterization of Prenatally Detected Chromosomal Structural Abnormalities Using Oligonucleotide Array Comparative Genomic Hybridization

    PubMed Central

    Li, Peining; Pomianowski, Pawel; DiMaio, Miriam S.; Florio, Joanne R.; Rossi, Michael R.; Xiang, Bixia; Xu, Fang; Yang, Hui; Geng, Qian; Xie, Jiansheng; Mahoney, Maurice J.

    2013-01-01

    Detection of chromosomal structural abnormalities using conventional cytogenetic methods poses a challenge for prenatal genetic counseling due to unpredictable clinical outcomes and risk of recurrence. Of the 1,726 prenatal cases in a 3-year period, we performed oligonucleotide array comparative genomic hybridization (aCGH) analysis on 11 cases detected with various structural chromosomal abnormalities. In nine cases, genomic aberrations and gene contents involving a 3p distal deletion, a marker chromosome from chromosome 4, a derivative chromosome 5 from a 5p/7q translocation, a de novo distal 6q deletion, a recombinant chromosome 8 comprised of an 8p duplication and an 8q deletion, an extra derivative chromosome 9 from an 8p/9q translocation, mosaicism for chromosome 12q with added material of initially unknown origin, an unbalanced 13q/15q rearrangement, and a distal 18q duplication and deletion were delineated. An absence of pathogenic copy number changes was noted in one case with a de novo 11q/14q translocation and in another with a familial insertion of 21q into a 19q. Genomic characterization of the structural abnormalities aided in the prediction of clinical outcomes. These results demonstrated the value of aCGH analysis in prenatal cases with subtle or complex chromosomal rearrangements. Furthermore, a retrospective analysis of clinical indications of our prenatal cases showed that approximately 20% of them had abnormal ultrasound findings and should be considered as high risk pregnancies for a combined chromosome and aCGH analysis. PMID:21671377

  17. Evaluation of a hemi-spherical wideband antenna array for breast cancer imaging

    NASA Astrophysics Data System (ADS)

    Klemm, M.; Craddock, I. J.; Preece, A.; Leendertz, J.; Benjamin, R.

    2008-12-01

    Using similar techniques to ground penetrating radars, microwave detection of breast tumors is a potential nonionizing and noninvasive alternative to traditional body-imaging techniques. In order to develop an imaging system, the team at Bristol have been working on a number of antenna array prototypes, based around a stacked-patch element, starting with simple pairs of elements and progressing to fully populated planar arrays. As the system commences human subject trials, a curved breast phantom has been developed along with an approximately hemi-spherical conformal array. This contribution will present details of the conformal array design and initial results from this unique experimental imaging system as applied to an anatomically shaped breast phantom.

  18. 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.

  19. Gold hybrid nanoparticles for targeted phototherapy and cancer imaging

    NASA Astrophysics Data System (ADS)

    Kirui, Dickson K.; Rey, Diego A.; Batt, Carl A.

    2010-03-01

    Gold and iron oxide hybrid nanoparticles (HNPs) synthesized by the thermal decomposition technique are bio-functionalized with a single chain antibody, scFv, that binds to the A33 antigen present on colorectal cancer cells. The HNP-scFv conjugates are stable in aqueous solution with a magnetization value of 44 emu g - 1 and exhibit strong optical absorbance at 800 nm. Here we test this material in targeting, imaging and selective thermal killing of colorectal cancer cells. Cellular uptake studies showed that A33-expressing cells take up the A33scFv-conjugated HNPs at a rate five times higher than cells that do not express the A33 antigen. Laser irradiation studies showed that approximately 53% of the A33-expressing cells exposed to targeted HNPs are killed after a six-minute laser treatment at 5.1 W cm - 2 using a 808 nm continuous wave laser diode while < 5% of A33-nonexpressing cells are killed. At a higher intensity, 31.5 W cm - 2, the thermal destruction increases to 99 and 40% for A33-expressing cells and A33 nonexpressing cells, respectively, after 6 min exposure. Flow cytometric analyses of the laser-irradiated A33 antigen-expressing cells show apoptosis-related cell death to be the primary mode of cell death at 5.1 W cm - 2, with increasing necrosis-related cell death at higher laser power. These results suggest that this new class of bio-conjugated hybrid nanoparticles can potentially serve as an effective antigen-targeted photothermal therapeutic agent for cancer treatment as well as a probe for magnetic resonance-based imaging.

  20. On-Demand Formation of Supported Lipid Membrane Arrays by Trehalose-Assisted Vesicle Delivery for SPR Imaging.

    PubMed

    Hinman, Samuel S; Ruiz, Charles J; Drakakaki, Georgia; Wilkop, Thomas E; Cheng, Quan

    2015-08-12

    The fabrication of large-scale, solid-supported lipid bilayer (SLB) arrays has traditionally been an arduous and complex task, primarily due to the need to maintain SLBs within an aqueous environment. In this work, we demonstrate the use of trehalose vitrified phospholipid vesicles that facilitate on-demand generation of microarrays, allowing each element a unique composition, for the label-free and high-throughput analysis of biomolecular interactions by SPR imaging (SPRi). Small, unilamellar vesicles (SUVs) are suspended in trehalose, deposited in a spatially defined manner, with the trehalose vitrifying on either hydrophilic or hydrophobic SPR substrates. SLBs are subsequently spontaneously formed on-demand simply by in situ hydration of the array in the SPR instrument flow cell. The resulting SLBs exhibit high lateral mobility, characteristic of fluidic cellular lipid membranes, and preserve the biological function of embedded cell membrane receptors, as indicated by SPR affinity measurements. Independent fluorescence and SPR imaging studies show that the individual SLBs stay localized at the area of deposition, without any encapsulating matrix, confining coral, or boundaries. The introduced methodology allows individually addressable SLB arrays to be analyzed with excellent label-free sensitivity in a real-time, high-throughput manner. Various protein-ganglioside interactions have been selected as a model system to illustrate discrimination of strong and weak binding responses in SPRi sensorgrams. This methodology has been applied toward generating hybrid bilayer membranes on hydrophobic SPR substrates, demonstrating its versatility toward a range of surfaces and membrane geometries. The stability of the fabricated arrays, over medium to long storage periods, was evaluated and found to be good. The highly efficient and easily scalable nature of the method has the potential to be applied to a variety of label-free sensing platforms requiring lipid membranes for

  1. 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.

  2. 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

  3. 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

  4. Top-Level System Designs for Hybrid Low-Field MRI-CT with Potential of Pulmonary Imaging

    NASA Astrophysics Data System (ADS)

    Yelleswarapu, Venkata R.; Liu, Fenglin; Cong, Wenxiang; Wang, Ge

    2014-11-01

    We previously discussed "omni-tomography", but intrinsic conflicts between the magnetic fields of the MRI and the X-ray tube within the CT are inherent. We propose that by using low-field MRI with a negligible fringe field at the site of the CT source, it is possible to create a CT-MRI system with minimal interference. Low field MRI is particularly useful for lung imaging, where hyperpolarized gas can enhance the signal. Three major designs were considered and simulated, with modifications in coil design and axis allowing for further variation. The first uses Halbach arrays to minimize magnetic fields outside, the second uses solenoids pairs with active shielding, and the third uses a rotating compact MRI-CT. Each system is low field, which may allow the implementation of a standard rotating CT. Both structural and functional information can be acquired simultaneously for a true hybrid image with matching temporal and spatial image acquisition.

  5. Study of Ultra-High Energy Cosmic Ray composition using Telescope Array's Middle Drum detector and surface array in hybrid mode

    NASA Astrophysics Data System (ADS)

    Abbasi, R. U.; Abe, M.; Abu-Zayyad, T.; Allen, M.; Anderson, R.; Azuma, R.; Barcikowski, E.; Belz, J. W.; Bergman, D. R.; Blake, S. A.; Cady, R.; Chae, M. J.; Cheon, B. G.; Chiba, J.; Chikawa, M.; Cho, W. R.; Fujii, T.; Fukushima, M.; Goto, T.; Hanlon, W.; Hayashi, Y.; Hayashida, N.; Hibino, K.; Honda, K.; Ikeda, D.; Inoue, N.; Ishii, T.; Ishimori, R.; Ito, H.; Ivanov, D.; Jui, C. C. H.; Kadota, K.; Kakimoto, F.; Kalashev, O.; Kasahara, K.; Kawai, H.; Kawakami, S.; Kawana, S.; Kawata, K.; Kido, E.; Kim, H. B.; Kim, J. H.; Kim, J. H.; Kitamura, S.; Kitamura, Y.; Kuzmin, V.; Kwon, Y. J.; Lan, J.; Lim, S. I.; Lundquist, J. P.; Machida, K.; Martens, K.; Matsuda, T.; Matsuyama, T.; Matthews, J. N.; Minamino, M.; Mukai, Y.; Myers, I.; Nagasawa, K.; Nagataki, S.; Nakamura, T.; Nonaka, T.; Nozato, A.; Ogio, S.; Ogura, J.; Ohnishi, M.; Ohoka, H.; Oki, K.; Okuda, T.; Ono, M.; Oshima, A.; Ozawa, S.; Park, I. H.; Pshirkov, M. S.; Rodriguez, D. C.; Rubtsov, G.; Ryu, D.; Sagawa, H.; Sakurai, N.; Sampson, A. L.; Scott, L. M.; Shah, P. D.; Shibata, F.; Shibata, T.; Shimodaira, H.; Shin, B. K.; Shin, H. S.; Smith, J. D.; Sokolsky, P.; Springer, R. W.; Stokes, B. T.; Stratton, S. R.; Stroman, T.; Suzawa, T.; Takamura, M.; Takeda, M.; Takeishi, R.; Taketa, A.; Takita, M.; Tameda, Y.; Tanaka, H.; Tanaka, K.; Tanaka, M.; Thomas, S. B.; Thomson, G. B.; Tinyakov, P.; Tkachev, I.; Tokuno, H.; Tomida, T.; Troitsky, S.; Tsunesada, Y.; Tsutsumi, K.; Uchihori, Y.; Udo, S.; Urban, F.; Vasiloff, G.; Wong, T.; Yamane, R.; Yamaoka, H.; Yamazaki, K.; Yang, J.; Yashiro, K.; Yoneda, Y.; Yoshida, S.; Yoshii, H.; Zollinger, R.; Zundel, Z.

    2015-04-01

    Previous measurements of the composition of Ultra-High Energy Cosmic Rays (UHECRs) made by the High Resolution Fly's Eye (HiRes) and Pierre Auger Observatory (PAO) are seemingly contradictory, but utilize different detection methods, as HiRes was a stereo detector and PAO is a hybrid detector. The five year Telescope Array (TA) Middle Drum hybrid composition measurement is similar in some, but not all, respects in methodology to PAO, and good agreement is evident between data and a light, largely protonic, composition when comparing the measurements to predictions obtained with the QGSJetII-03 and QGSJet-01c models. These models are also in agreement with previous HiRes stereo measurements, confirming the equivalence of the stereo and hybrid methods. The data is incompatible with a pure iron composition, for all models examined, over the available range of energies. The elongation rate and mean values of Xmax are in good agreement with Pierre Auger Observatory data. This analysis is presented using two methods: data cuts using simple geometrical variables and a new pattern recognition technique.

  6. Automatic identification of ROI in figure images toward improving hybrid (text and image) biomedical document retrieval

    NASA Astrophysics Data System (ADS)

    You, Daekeun; Antani, Sameer; Demner-Fushman, Dina; Rahman, Md Mahmudur; Govindaraju, Venu; Thoma, George R.

    2011-01-01

    Biomedical images are often referenced for clinical decision support (CDS), educational purposes, and research. They appear in specialized databases or in biomedical publications and are not meaningfully retrievable using primarily textbased retrieval systems. The task of automatically finding the images in an article that are most useful for the purpose of determining relevance to a clinical situation is quite challenging. An approach is to automatically annotate images extracted from scientific publications with respect to their usefulness for CDS. As an important step toward achieving the goal, we proposed figure image analysis for localizing pointers (arrows, symbols) to extract regions of interest (ROI) that can then be used to obtain meaningful local image content. Content-based image retrieval (CBIR) techniques can then associate local image ROIs with identified biomedical concepts in figure captions for improved hybrid (text and image) retrieval of biomedical articles. In this work we present methods that make robust our previous Markov random field (MRF)-based approach for pointer recognition and ROI extraction. These include use of Active Shape Models (ASM) to overcome problems in recognizing distorted pointer shapes and a region segmentation method for ROI extraction. We measure the performance of our methods on two criteria: (i) effectiveness in recognizing pointers in images, and (ii) improved document retrieval through use of extracted ROIs. Evaluation on three test sets shows 87% accuracy in the first criterion. Further, the quality of document retrieval using local visual features and text is shown to be better than using visual features alone.

  7. Antenna coupled Kinetic Inductance arrays for space and ground based imaging arrays

    NASA Astrophysics Data System (ADS)

    Yates, S. J. C.; Baselmans, J. J. A.; Baryshev, A. M.; Neto, A.; Gerini, G.; Barends, R.; Lankwarden, Y. J. Y.

    2009-12-01

    Very large arrays of Microwave Kinetic Inductance Detectors (MKIDs) have the potential to revolutionize ground and space based astronomy. They can offer in excess of 10000 pixels with large dynamic range and very high sensitivity in combination with very efficient frequency division multiplexing at GHz frequencies. In this paper we present the development for a ~100 pixel MKID demonstration array based upon an single pixel consisting of an integrated MKID-antenna detector, with the antenna placed in the second focus of an elliptical Si lens. The design presented can be scaled to any frequency between 80 GHz and >5 THz because there is no need for superconducting structures that become lossy at frequencies above the gap frequency of the materials used. We present measurements of the optical coupling efficiency, sensitivity and discuss array development. We have obtained a dark sensitivity of 7×10-19W/Hz1/2 using 100 nm thick A1 devices and an optical coupling efficiency of 35% referring to the power of a single polarization optical signal in front of the Si lens of the detector.

  8. 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.

  9. A dual mode imaging array for damage detection in grout structures

    NASA Astrophysics Data System (ADS)

    Tian, Zhenhua; Yu, Lingyu; EL-Batanouny, Mohamed; Ziehl, Paul; Zhao, Liuxian

    2013-04-01

    Due to the heterogeneous nature of the cement-based materials, the ultrasonic waves in concrete exhibit highly scattering and attenuation, leading to the difficulty of concrete damaged detection. This paper presents a dual mode ultrasonic array imaging methodology that can map damage using Rayleigh surface waves and permanently installed piezoelectric sensors. The dual mode sensing integrates passive acoustic emission and active ultrasonic wave inspection. When a crack is developing, acoustic emission (AE) occurs and the disturbance can propagate outwards along the structure surface. A novel AE source imaging algorithm has been developed to detect and locate the AE source. Once the AE source is located, the sensor array switches to its active mode. For active sensing, one sensor in the array is used to generate Rayleigh wave for interrogation, while all the others are used as the wave receivers. All the sensory data are processed by the active ultrasonic array imaging algorithm. The proof-of-concept testing was performed on a grout specimen with representative dimensions. The passive array imaging algorithm was able to locate the AE source simulated by pencil lead break while active sensing imaging was able to detect the damage simulated by a hole. The duel mode imaging method is promising and economically beneficial for solving a key source localization problem in damage detection on large concrete structures.

  10. Waveguide piezoelectric micromachined ultrasonic transducer array for short-range pulse-echo imaging

    NASA Astrophysics Data System (ADS)

    Lu, Y.; Tang, H.; Wang, Q.; Fung, S.; Tsai, J. M.; Daneman, M.; Boser, B. E.; Horsley, D. A.

    2015-05-01

    This paper presents an 8 × 24 element, 100 μm-pitch, 20 MHz ultrasound imager based on a piezoelectric micromachined ultrasonic transducer (PMUT) array having integrated acoustic waveguides. The 70 μm diameter, 220 μm long waveguides function both to direct acoustic waves and to confine acoustic energy, and also to provide mechanical protection for the PMUT array used for surface-imaging applications such as an ultrasonic fingerprint sensor. The imager consists of a PMUT array bonded with a CMOS ASIC using wafer-level conductive eutectic bonding. This construction allows each PMUT in the array to have a dedicated front-end receive amplifier, which together with on-chip analog multiplexing enables individual pixel read-out with high signal-to-noise ratio through minimized parasitic capacitance between the PMUT and the front-end amplifier. Finite element method simulations demonstrate that the waveguides preserve the pressure amplitude of acoustic pulses over distances of 600 μm. Moreover, the waveguide design demonstrated here enables pixel-by-pixel readout of the ultrasound image due to improved directivity of the PMUT by directing acoustic waves and creating a pressure field with greater spatial uniformity at the end of the waveguide. Pulse-echo imaging experiments conducted using a one-dimensional steel grating demonstrate the array's ability to form a two-dimensional image of a target.

  11. 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.

  12. 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.

  13. Real-time photoacoustic imaging based on multielement linear transducer array

    NASA Astrophysics Data System (ADS)

    Yin, Bangzheng; Xing, Da; Wang, Yi; Zeng, Yaguang; Tan, Yi

    2005-01-01

    A real-time photoacoustic (PA) imaging system based on multi-element linear transducer array was developed and test on phantoms. A Q switched Nd:YAG laser operating at 532 nm and 20Hz repeat rate was used in our experiment as thermal source. The multi-element linear transducer array consists of 320 elements. By phase-controlled method, 64 signals, one of which gathered by 11-group element, make up of an image. It was acquired in only about 3 seconds. Phantom experiment results can map the distribution of the optical absorption correctly. Compared to other existing technology and algorithm, the PA imaging based on transducer array was characterize by speediness and convenience. It can provide a new approach for tissue functional imaging in vivo, and may have potentials in developing into an appliance for clinic diagnosis.

  14. Dispersion-based imaging for structural health monitoring using sparse and compact arrays

    NASA Astrophysics Data System (ADS)

    Quaegebeur, N.; Masson, P.; Langlois-Demers, D.; Micheau, P.

    2011-02-01

    In this paper, a technique called 'excitelet' is presented for the imaging of damage in structures using the correlation of the signals measured at elements of piezoceramic arrays with dispersed versions of the excitation signal. This approach is presented as an extension of classical imaging techniques and takes advantage of the chirplet-based matching pursuit algorithm. The applicability for sparse and compact arrays is investigated experimentally on an aluminum plate and comparison with the existing embedded ultrasonic structural radar (EUSR) algorithm is performed for A0 and S0 modes for three frequency ranges of interest. Significant improvement of imaging quality is demonstrated with respect to imaging techniques using time-of-flight (ToF) and group velocity considerations for both sparse and compact piezoceramic array arrangements.

  15. Comparison Between Eight- and Sixteen-Channel TEM Transceive Arrays for Body Imaging at 7 Tesla

    PubMed Central

    Snyder, CJ; DelaBarre, L; Moeller, S; Tian, J; Akgun, C; Van De Moortele, P-F; Bolan, PJ; Ugurbil, K; Vaughan, JT; Metzger, GJ

    2011-01-01

    Eight- and sixteen-channel transceive stripline/TEM body arrays were compared at 7 tesla (297 MHz) both in simulation and experimentally. Despite previous demonstrations of similar arrays for use in body applications, a quantitative comparison of the two configurations has not been undertaken to date. Results were obtained on a male pelvis for assessing transmit, SNR and parallel imaging performance and to evaluate local power deposition versus transmit B1 (B1+). All measurements and simulations were conducted after performing local B1+ phase shimming in the region of the prostate. Despite the additional challenges of decoupling immediately adjacent coils, the sixteen-channel array demonstrated improved or nearly equivalent performance to the eight-channel array based on the evaluation criteria. Experimentally, transmit performance and SNR were 22% higher for the sixteen-channel array while significantly increased reduction factors were achievable in the left-right direction for parallel imaging. Finite-difference time-domain simulations demonstrated similar results with respect to transmit and parallel imaging performance, however a higher transmit efficiency advantage of 33% was predicted. Simulations at both 3T and 7T verified the expected parallel imaging improvements with increasing field strength and showed that, for a specific B1+ shimming strategy employed, the sixteen-channel array exhibited lower local and global SAR for a given B1+. PMID:22102483

  16. Bistatic receiver model for airborne lidar returns incident on an imaging array from underwater objects.

    PubMed

    Cadalli, Nail; Munson, David C; Singer, Andrew C

    2002-06-20

    We develop a bistatic model for airborne lidar returns collected by an imaging array from underwater objects, incorporating additional returns from the surrounding water medium and ocean bottom. Our results provide a generalization of the monostatic model by Walker and McLean. In the bistatic scheme the transmitter and receiver are spatially separated or are not coaligned. This generality is necessary for a precise description of an imaging array such as a CCD, which may be viewed as a collection of receiver elements, with each transmitter-element pair forming a bistatic configuration. More generally, the receiver may consist of photomultiplier tubes, photodiodes, or any of a variety of optical receivers, and the imaging array can range in size from a CCD array to a multiple-platform airborne lidar system involving multiple aircraft. The majority of this research is devoted to a derivation of the bistatic lidar equations, which account for multiple scattering and absorption in the water column. We then describe the application of these equations to the modeling and simulation of an imaging array. We show an example of a simulated lidar return and compare it with a real ocean lidar return, obtained by a CCD array. PMID:12078691

  17. 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

  18. An innovative detector concept for hybrid 4D-PET/MRI imaging

    NASA Astrophysics Data System (ADS)

    Cerello, P.; Pennazio, F.; Bisogni, M. G.; Marino, N.; Marzocca, C.; Peroni, C.; Wheadon, R.; Del Guerra, A.

    2013-02-01

    The importance of a high-quality hybrid imaging, providing morphological and functional information with only one acquisition session, is widely acknowledged by the scientific community. The historical limitations to the quality of PET images are related to the unsatisfactory measurement of the depth of interaction (DOI) in the crystals and of the time of flight (TOF), that cause a parallax error and an unfavorable signal to background condition in the image reconstruction process, respectively. The 4DMPET project is developing a high performance PET block-detector featuring 4D image reconstruction capabilities. The detector module is based on a fast scintillating continuous crystal coupled on both sides to arrays of Silicon PhotoMultipliers (SiPM). The SiPMs collect the scintillation light and provide the trigger signal, the time and the energy released in the crystal at the pixel level. The photon depth of interaction (DOI) is reconstructed by measuring the cluster size asymmetry on the two faces of the crystal, thus obtaining a comparable spatial resolution in the three coordinates and removing the parallax error. The event position along the line of response can be measured with high precision by means of TOF techniques. We discuss the module design concept and the results of the detailed Monte Carlo detector simulation, which inspire the architectural solutions selected for the layout and the front-end The expected resolution for 3D spatial coordinates of the interaction point in the crystal (1 mm) and the TOF (about 110 ps) would provide a substantial improvement of the image quality. 4DMPET aims at building a prototype block detector demonstrating that the proposed layout meets the expected performance and is suitable for designing a detector focused on a specific application.

  19. Computed tomography imaging spectrometer by using a novel hybrid diffractive-refractive element

    NASA Astrophysics Data System (ADS)

    Fan, Dongdong; Wu, Minxian; He, Qingsheng; Yong, Tao; Wei, Haoyun

    2001-09-01

    The multi-spectal or hyper-spectral imager provides three dimensional description for spatial and spectral intensity distribution of objective scenes and it can be a powerful tool for remote sensing in much application. There are several approaches to collection three dimensional data cube of image, and most of them require a scanning mechanism. Therefore those methods are difficult to record both spectral and spatial information of a dynamic scene such as a missile in flight, changing rapidly red tide, and so forth. Computed Tomography Imaging Spectrometer (CTIS) is a new branch application of computed tomography technology. The CTISs with different type configuration have been reported by a few of author. Two main types of CTISs are proposed. One is to use the two dimension gratings like Dammann gratings, the two 1-D gratings placed in orthogonal way, or three 1-D gratings separated by 60 degree. Due to its temporally and spatially non-scanning technique, this type is capable of capturing the flash events and can be used for instantaneous spectral imaging. The main problem of these CTISs is that the diffractive efficiencies are not only depended on the various wavelength but also on the different diffractive orders. That will effect the reconstruction algorithm and its results. These problems lead to reduce the signal to noise and dynamic range of spectral imaging system. The other is to take the approaches such as rotational spectro-tomography, or grating combined with a rotational direct-view prism. The advantages of these approaches are a)high throughput and b)easy to obtain more uniform data of different projection, but its disadvantage is obvious that the moving parts must be adopted. In our work, a principle and configuration of CTIS is indicated, and especially, a novel hybrid diffractive-refractive element is proposed, which is a combination of an array of optical prisms and one dimension holographic gratings. It can provide the uniformity of performance

  20. Clinical Utility of Array Comparative Genomic Hybridization for Detection of Chromosomal Abnormalities in Pediatric Acute Lymphoblastic Leukemia

    PubMed Central

    Rabin, Karen R.; Man, Tsz-Kwong; Yu, Alexander; Folsom, Matthew R.; Zhao, Yi-Jue; Rao, Pulivarthi H.; Plon, Sharon E.; Naeem, Rizwan C.

    2014-01-01

    Background Accurate detection of recurrent chromosomal abnormalities is critical to assign patients to risk-based therapeutic regimens for pediatric acute lymphoblastic leukemia (ALL). Procedure We investigated the utility of array comparative genomic hybridization (aCGH) for detection of chromosomal abnormalities compared to standard clinical evaluation with karyotype and fluorescent in-situ hybridization (FISH). Fifty pediatric ALL diagnostic bone marrows were analyzed by bacterial artificial chromosome (BAC) array, and findings compared to standard clinical evaluation. Results Sensitivity of aCGH was 79% to detect karyotypic findings other than balanced translocations, which cannot be detected by aCGH because they involve no copy number change. aCGH also missed abnormalities occurring in subclones constituting less than 25% of cells. aCGH detected 44 additional abnormalities undetected or misidentified by karyotype, 21 subsequently validated by FISH, including abnormalities in 4 of 10 cases with uninformative cytogenetics. aCGH detected concurrent terminal deletions of both 9p and 20q in three cases, in two of which the 20q deletion was undetected by karyotype. A narrow region of loss at 7p21 was detected in two cases. Conclusions An array with increased BAC density over regions important in ALL, combined with PCR for fusion products of balanced translocations, could minimize labor- and time-intensive cytogenetic assays and provide key prognostic information in the approximately 35% of cases with uninformative cytogenetics. PMID:18253961

  1. Geometric Correction of Airborne Linear Array Image Based on Bias Matrix

    NASA Astrophysics Data System (ADS)

    Wang, M.; Hu, J.; Zhou, M.; Li, J. M.; Zhang, Z.

    2013-05-01

    As the linear array sensor has great potential in disaster monitoring, geological survey, the quality of the image geometric correction should be guaranteed. The primary focus of this paper is to present a new method correcting airbone linear image based on the bias matrix,which is bulit by describing and analysing the errors of airbone linear image included the misalignment. The bias matrix was considered as additional observations to the traditional geometric correction model in our method. And by using control points which have both image coordinate and object coordinate, the solving equation from geometric correction model can be established and the bias matrix can be calculated by adjustment strategy. To avoid the singularity problem in the calculating process, this paper uses quaternion to describe the image's attitude and rotation instead of traditional calculating method which is structured by the Euler angle. Finally, geometric correction of airborne linear array image with high accuracy based on bias matrix can be achieved.

  2. 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. PMID:27231634

  3. 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

  4. 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.

  5. 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

  6. 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.

  7. 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.

  8. 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. PMID:25392561

  9. 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. PMID:25994706

  10. 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.

  11. MTF measurements with high-resolution a-Si:H imaging arrays

    NASA Astrophysics Data System (ADS)

    Yorkston, John; Antonuk, Larry E.; Seraji, N.; Huang, Weidong; Siewerdsen, Jeffrey H.; El-Mohri, Youcef

    1995-05-01

    Recent advances in a-Si:H fabrication technology have opened the way for the application of flat panel imaging arrays in a number of areas in medical imaging. Their large area (up to approximately 26 X 26 cm), thin profile (< 1 mm) and real time readout capability make them strong candidates for the replacement of more traditional x-ray imaging technologies such as film and image intensifier systems. As a first step towards a device suitable for clinical use we have created a 24.4 X 19.4 cm array with 127 micrometers pitch pixels. This device serves as a testbed for investigating the effects of design changes on array imaging performance. This paper reports on initial measurements of the spatial resolution of this device used in conjunction with an overlaying Lanex Regular screen and 90 kVp x rays. The measured pre-sampled modulation transfer function (p.s. MTF) is found to fall below the predicted value by up to approximately 8%. At least part of this reduction seems to be due to scattering of light photons between the array and the surface of the phosphor screen contacting the array.

  12. 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.

  13. Near-field imaging and spectroscopy of hybridized plasmons (Presentation Recording)

    NASA Astrophysics Data System (ADS)

    Aeschlimann, Martin

    2015-09-01

    Understanding light-matter interactions such as the dynamic response of a metal to incident light is essential for advancing fundamental research and technological applications e.g. designing plasmonic devices such as nanoantenna directional emitters. The near-field response is determined on a length scale that is intrinsically smaller than the optical diffraction limit and so we use electrons to image the near-field distribution. We combine photoemission electron microscopy (PEEM) with a variable wavelength laser light source, an optical parametric oscillator (OPO), to perform near-field imaging and spectroscopy of whispering gallery resonator (WGR)1 arrays. These ultrahigh spatially and spectrally resolved measurements show characteristic spectral peaks and near-field mode distributions due to the excitation of different plasmon resonances. Controlling the interference between dipole and quadrupole modes allows us to direct the emission from the nanoantenna. Additionally we perform femtosecond 2-dimensional coherence spectroscopy2 on a microcavity system containing two well separated WGR nanoantennas. Hybridization of a propagating surface plasmon polariton and the localized surface plasmon in a cavity enables energy transfer between the two coupled nanoantennas. [1] E. J. R. Vessseur, F. J. García de Abajo and A. Polman Nano Letters 9 3147 (2009) [2] M. Aeschlimann et al, Science 333, 1723 (2011)

  14. MR imaging with remote reception using a coil array

    NASA Astrophysics Data System (ADS)

    Vazquez, F.; Marrufo, O.; Martin, R.; Rodriguez, A. O.

    2012-10-01

    A strategy for imaging a large field-of-view has recently been proposed applying remote detection with a waveguide and single loop coils. RF coils produce a traveling-wave propagating through the bore of the magnet, which is large enough so the cutoff frequency is below the Larmor frequency. This assumption also considers that a human subject inside the magnet bore. We applied the travelling-wave concept to generate images of a human leg at 3 Tesla. Two circular-shaped coils were used as the reception device and a whole-body coil was used for transmission. Images showed a good signal-to-noise ratio along the entire leg. This experimental results contradict the assumption that a whole-body 7T/65cm imager or higher was necessary to generate images with this approach.

  15. High-resolution CCD imagers using area-array CCD's for sensing spectral components of an optical line image

    NASA Technical Reports Server (NTRS)

    Elabd, Hammam (Inventor); Kosonocky, Walter F. (Inventor)

    1987-01-01

    CCD imagers with a novel replicated-line-imager architecture are abutted to form an extended line sensor. The sensor is preceded by optics having a slit aperture and having an optical beam splitter or astigmatic lens for projecting multiple line images through an optical color-discriminating stripe filter to the CCD imagers. A very high resolution camera suitable for use in a satellite, for example, is thus provided. The replicated-line architecture of the imager comprises an area-array CCD, successive rows of which are illuminated by replications of the same line segment, as transmitted by respective color filter stripes. The charge packets formed by accumulation of photoresponsive charge in the area-array CCD are read out row by row. Each successive row of charge packets is then converted from parallel to serial format in a CCD line register and its amplitude sensed to generate a line of output signal.

  16. Scalable nanopillar arrays with layer-by-layer patterned overt and covert images.

    PubMed

    Lee, Kyoung G; Choi, Bong Gill; Kim, Byeong Il; Shyu, Terry; Oh, Myung Seok; Im, Sung Gap; Chang, Sung-Jin; Lee, Tae Jae; Kotov, Nicholas A; Lee, Seok Jae

    2014-09-17

    Transferring flexible and scalable nano-pillar arrays on a variety of unconventional substrates, including fabric, paper, and metals, is achieved by a single-step replication process using UV-curable polymers. Local alteration of the contact angle on the nanopillar arrays by LBL films creates selectively hidden images. They can be revealed by the breath and used as an innovative anti-counterfeit technology. PMID:25100005

  17. 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.

  18. Analysis of the depth of field in hexagonal array integral imaging systems based on modulation transfer function and Strehl ratio.

    PubMed

    Karimzadeh, Ayatollah

    2016-04-10

    Integral imaging is a technique for displaying three-dimensional images using microlens arrays. In this paper, a method for calculating root mean squared wavefront error and modulation transfer function (MTF) of a defocused integral imaging capture system with hexagonal aperture microlens arrays is introduced. Also, maximum allowable depth of field with Century MTF analyzing and Strehl criterion are obtained. PMID:27139873

  19. 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.

  20. Optical image classification using optical/digital hybrid image-processing systems

    SciTech Connect

    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. The author applies 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, he proposes the feature extraction perceptron. The application of feature extraction techniques to the perceptron shortens its learning time.

  1. A Medium-Format, Mixed-Mode Pixel Array Detector for Kilohertz X-ray Imaging

    NASA Astrophysics Data System (ADS)

    Tate, M. W.; Chamberlain, D.; Green, K. S.; Philipp, H. T.; Purohit, P.; Strohman, C.; Gruner, S. M.

    2013-03-01

    An x-ray pixel array detector (PAD) capable of framing up to 1 kHz is described. This hybrid detector is constructed from a 3-side buttable, 128×128 pixel module based upon the mixed-mode pixel array detector (MMPAD) chip developed jointly by Cornell and Area Detector Systems Corporation (Poway, CA). The chip uses a charge integrating front end for a high instantaneous count rate yet with single photon sensitivity. In-pixel circuitry utilizing a digital overflow counter extends the per frame dynamic range to >4×107 x-rays/pixel. Results are shown from a base configuration of a 2×3 module array (256×384 pixels).

  2. Carbon-coated silicon nanotube arrays on carbon cloth as a hybrid anode for lithium-ion batteries

    NASA Astrophysics Data System (ADS)

    Wang, Wei; Gu, Lin; Qian, Haolei; Zhao, Ming; Ding, Xi; Peng, Xinsheng; Sha, Jian; Wang, Yewu

    2016-03-01

    Silicon hollow nanostructure has been considered as one of the most promising material for commercial application in lithium-ion batteries due to its significant improvement of cycling stability. The fabricated hybrid structures, carbon-coated silicon nanotube arrays on carbon cloth substrate, with a high surface area and short electron collection pathway have been directly used as anode electrodes without any additional binder. The electrodes exhibit high capacity, excellent rate capability and good cycling stability. The discharge capacity of the hybrid electrode (the deposition time of silicon shell: 5 min) keeps stable, and after 100 cycles, the discharge capacities still remain 3654 mAh g-1 at the rate of 0.5 C.

  3. FeOOH/Co/FeOOH Hybrid Nanotube Arrays as High-Performance Electrocatalysts for the Oxygen Evolution Reaction.

    PubMed

    Feng, Jin-Xian; Xu, Han; Dong, Yu-Tao; Ye, Sheng-Hua; Tong, Ye-Xiang; Li, Gao-Ren

    2016-03-01

    Herein, we developed FeOOH/Co/FeOOH hybrid nanotube arrays (HNTAs) supported on Ni foams for oxygen evolution reaction (OER). The inner Co metal cores serve as highly conductive layers to provide reliable electronic transmission, and can overcome the poor electrical conductivity of FeOOH efficiently. DFT calculations demonstrate the strong electronic interactions between Co and FeOOH in the FeOOH/Co/FeOOH HNTAs, and the hybrid structure can lower the energy barriers of intermediates and thus promote the catalytic reactions. The FeOOH/Co/FeOOH HNTAs exhibit high electrocatalytic performance for OER, such as low onset potential, small Tafel slope, and excellent long-term durability, and they are promising electrocatalysts for OER in alkaline solution. PMID:26879125

  4. A High-Frequency High Frame Rate Duplex Ultrasound Linear Array Imaging System for Small Animal Imaging

    PubMed Central

    Zhang, Lequan; Xu, Xiaochen; Hu, Changhong; Sun, Lei; Yen, Jesse T.; Cannata, Jonathan M.; Shung, K. Kirk

    2010-01-01

    High-frequency (HF) ultrasound imaging has been shown to be useful for non-invasively imaging anatomical structures of the eye and small animals in biological and pharmaceutical research, achieving superior spatial resolution. Cardiovascular research utilizing mice requires not only real-time B-scan imaging, but also ultrasound Doppler to evaluate both anatomy and blood flow of the mouse heart. This paper reports the development of a high frequency ultrasound duplex imaging system capable of both B-mode imaging and Doppler flow measurements, using a 64-element linear array. The system included a HF pulsed-wave Doppler module, a 32-channel HF B-mode imaging module, a PC with a 200 MS/s 14-bit A/D card, and real-time LabView software. A 50dB signal-to-noise ratio (SNR) and a depth of penetration of larger than 12 mm were achieved using a 35 MHz linear array with 50 μm pitch. The two-way beam widths were determined to be 165 μm to 260 μm and the clutter energy to total energy ratio (CTR) were 9.1 dB to 12 dB, when the array was electronically focused at different focal points at depths from 4.8 mm to 9.6 mm. The system is capable of acquiring real-time B-mode images at a rate greater than 400 frames per second (fps) for a 4.8 × 13 mm field of view, using a 30 MHz 64-element linear array with 100 μm pitch. Sample in vivo cardiac high frame rate images and duplex images of mouse hearts are shown to assess its current imaging capability and performance for small animals. PMID:20639149

  5. 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

  6. 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.

  7. 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.

  8. 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

  9. A hybrid finite element method for scattering and radiation by microstrip patch antennas and arrays residing in a cavity

    NASA Astrophysics Data System (ADS)

    Jin, Jian-Ming; Volakis, John L.

    1991-11-01

    A hybrid numerical technique is presented for a characterization of the scattering and radiation properties of microstrip patch antennas and arrays residing in a cavity recessed in a ground plane. The technique combines the finite-element and boundary integral methods to formulate a system for the solution of the fields at the aperture and those inside the cavity via the biconjugate gradient method in conjunction with the fast Fourier transform (FFT). By virtue of the finite-element method, the proposed technique is applicable to patch antennas and arrays residing on or embedded in a layered dielectric substrate and is also capable of treating various feed configurations and impedance loads. Several numerical results are presented, demonstrating the validity, efficiency, and capability of the technique.

  10. Improved 2-D resistivity imaging of features in covered karst terrain with arrays of implanted electrodes

    NASA Astrophysics Data System (ADS)

    Kiflu, H. G.; Kruse, S. E.; Harro, D.; Loke, M. H.; Wilkinson, P. B.

    2013-12-01

    28-electrode arrays with electrodes 2-5 meters apart, and the deep arrays buried at 4-8 meters depth. Ground penetrating radar surveys, SPT borings and coring data provide selected 'ground truthing'. The case studies show that inclusion of the deep electrode array permits karst features such as undulations at the top of limestone and raveling zones within surficial sediments to be imaged. These features are not accessible from surface arrays with equivalent surface footprints. The method also has better resolution at depth at the ends of the lines, where surface arrays are typically plotted with a trapezoidal truncation due to poor resolution at the lower corners of the profile.

  11. Energy spectrum of ultra-high energy cosmic rays observed with the Telescope Array using a hybrid technique

    NASA Astrophysics Data System (ADS)

    Abu-Zayyad, T.; Aida, R.; Allen, M.; Anderson, R.; Azuma, R.; Barcikowski, E.; Belz, J. W.; Bergman, D. R.; Blake, S. A.; Cady, R.; Cheon, B. G.; Chiba, J.; Chikawa, M.; Cho, E. J.; Cho, W. R.; Fujii, H.; Fujii, T.; Fukuda, T.; Fukushima, M.; Hanlon, W.; Hayashi, K.; Hayashi, Y.; Hayashida, N.; Hibino, K.; Hiyama, K.; Honda, K.; Iguchi, T.; Ikeda, D.; Ikuta, K.; Inoue, N.; Ishii, T.; Ishimori, R.; Ito, H.; Ivanov, D.; Iwamoto, S.; Jui, C. C. H.; Kadota, K.; Kakimoto, F.; Kalashev, O.; Kanbe, T.; Kasahara, K.; Kawai, H.; Kawakami, S.; Kawana, S.; Kido, E.; Kim, H. B.; Kim, H. K.; Kim, J. H.; Kim, J. H.; Kitamoto, K.; Kitamura, S.; Kitamura, Y.; Kobayashi, K.; Kobayashi, Y.; Kondo, Y.; Kuramoto, K.; Kuzmin, V.; Kwon, Y. J.; Lan, J.; Lim, S. I.; Lundquist, J. P.; Machida, S.; Martens, K.; Matsuda, T.; Matsuura, T.; Matsuyama, T.; Matthews, J. N.; Minamino, M.; Miyata, K.; Murano, Y.; Myers, I.; Nagasawa, K.; Nagataki, S.; Nakamura, T.; Nam, S. W.; Nonaka, T.; Ogio, S.; Ohnishi, M.; Ohoka, H.; Oki, K.; Oku, D.; Okuda, T.; Ono, M.; Oshima, A.; Ozawa, S.; Park, I. H.; Pshirkov, M. S.; Rodriguez, D. C.; Roh, S. Y.; Rubtsov, G.; Ryu, D.; Sagawa, H.; Sakurai, N.; Sampson, A. L.; Scott, L. M.; Shah, P. D.; Shibata, F.; Shibata, T.; Shimodaira, H.; Shin, B. K.; Shin, J. I.; Shirahama, T.; Smith, J. D.; Sokolsky, P.; Springer, R. W.; Stokes, B. T.; Stratton, S. R.; Stroman, T.; Suzuki, S.; Takahashi, Y.; Takeda, M.; Taketa, A.; Takita, M.; Tameda, Y.; Tanaka, H.; Tanaka, K.; Tanaka, M.; Thomas, S. B.; Thomson, G. B.; Tinyakov, P.; Tkachev, I.; Tokuno, H.; Tomida, T.; Troitsky, S.; Tsunesada, Y.; Tsutsumi, K.; Tsuyuguchi, Y.; Uchihori, Y.; Udo, S.; Ukai, H.; Urban, F.; Vasiloff, G.; Wada, Y.; Wong, T.; Yamakawa, Y.; Yamane, R.; Yamaoka, H.; Yamazaki, K.; Yang, J.; Yoneda, Y.; Yoshida, S.; Yoshii, H.; Zhou, X.; Zollinger, R.; Zundel, Z.

    2015-02-01

    We measure the spectrum of cosmic rays with energies greater than 1018.2 eV with the fluorescence detectors (FDs) and the surface detectors (SDs) of the Telescope Array Experiment using the data taken in our first 2.3-year observation from May 27, 2008 to September 7, 2010. A hybrid air shower reconstruction technique is employed to improve accuracies in determination of arrival directions and primary energies of cosmic rays using both FD and SD data. The energy spectrum presented here is in agreement with our previously published spectra and the HiRes results.

  12. Direct photofabrication of focal-length-controlled microlens array using photoinduced migration mechanisms of photosensitive sol-gel hybrid materials

    NASA Astrophysics Data System (ADS)

    Kang, Dong Jun; Jeong, Jong-Pil; Bae, Byeong-Soo

    2006-09-01

    Photosensitive sol-gel hybrid (SGH) materials exhibited the peculiar photoinduced migration behavior of unreacted molecules from unexposed areas to exposed areas by selective UV exposure. Using the photoinduced migration mechanism of the photosensitive SGH materials, the microlens array (MLA) with a smooth surface was directly photofabricated, and the focal length was controlled by changing the photoinduced migration parameters. The higher photoactive monomer content and the thicker film creating a higher curvature produced a smaller focal length of the MLA. Thus, a simple fabrication and easy control of the focal length can be applicable to a fabrication of an efficient MLA.

  13. 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

  14. A photoacoustic imager with light illumination through an infrared-transparent silicon CMUT array.

    PubMed

    Chen, Jingkuang; Wang, Mengli; Cheng, Jui-Ching; Wang, Yu-Hsin; Li, Pai-Chi; Cheng, Xiaoyang

    2012-04-01

    A novel hardware design and preliminary experimental results for photoacoustic imaging are reported in this paper. This imaging system makes use of an infrared-transparent capacitive micromachined ultrasonic transducer (CMUT) chip for ultrasound reception and illuminates the image target through the CMUT array. The cascaded arrangement between the light source and transducer array allows for a more compact imager head and results in more uniform illumination. Taking advantage of the low optical absorption coefficient of silicon in the near infrared spectrum as well as the broad acoustic bandwidth that CMUTs provide, an infrared-transparent CMUT array has been developed for ultrasound reception. The center frequency of the polysilicon-membrane CMUT devices used in this photoacoustic system is 3.5 MHz, with a fractional bandwidth of 118% in reception mode. The silicon substrate of the CMUT array has been thinned to 100 μm and an antireflection dielectric layer is coated on the back side to improve the infrared-transmission rate. Initial results show that the transmission rate of a 1.06-μm Nd:Yag laser through this CMUT chip is 12%. This transmission rate can be improved if the thickness of silicon substrate and the thin-film dielectrics in the CMUT structure are properly tailored. Imaging of a metal wire phantom using this cascaded photoacoustic imager is demonstrated. PMID:22547287

  15. An integral imaging method for depth extraction with lens array in an optical tweezer system

    NASA Astrophysics Data System (ADS)

    Wang, Shulu; Liu, Wei-Wei; Wang, Anting; Li, Yinmei; Ming, Hai

    2014-10-01

    In this paper, a new integral imaging method is proposed for depth extraction in an optical tweezer system. A mutual coherence algorithm of stereo matching are theoretically analyzed and demonstrated feasible by virtual simulation. In our design, optical tweezer technique is combined with integral imaging in a single microscopy system by inserting a lens array into the optical train. On one hand, the optical tweezer subsystem is built based on the modulated light field from a solid laser, and the strong focused beam forms a light trap to capture tiny specimens. On the other hand, through parameters optimization, the microscopic integral imaging subsystem is composed of a microscope objective, a lens array (150x150 array with 0.192mm unit size and 9mm focal length) and a single lens reflex (SLR). Pre-magnified by the microscope objective, the specimens formed multiple images through the lens array. A single photograph of a series of multiple sub-images has recorded perspective views of the specimens. The differences between adjacent sub-images have been analyzed for depth extraction with the mutual coherence algorithm. The experimental results show that the axial resolution can reach to 1μm -1 and lateral resolution can reach to 2 μm -1.

  16. Real-time system for imaging and object detection with a multistatic GPR array

    SciTech Connect

    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.

  17. 3D imaging LADAR with linear array devices: laser, detector and ROIC

    NASA Astrophysics Data System (ADS)

    Kameyama, Shumpei; Imaki, Masaharu; Tamagawa, Yasuhisa; Akino, Yosuke; Hirai, Akihito; Ishimura, Eitaro; Hirano, Yoshihito

    2009-07-01

    This paper introduces the recent development of 3D imaging LADAR (LAser Detection And Ranging) in Mitsubishi Electric Corporation. The system consists of in-house-made key devices which are linear array: the laser, the detector and the ROIC (Read-Out Integrated Circuit). The laser transmitter is the high power and compact planar waveguide array laser at the wavelength of 1.5 micron. The detector array consists of the low excess noise Avalanche Photo Diode (APD) using the InAlAs multiplication layer. The analog ROIC array, which is fabricated in the SiGe- BiCMOS process, includes the Trans-Impedance Amplifiers (TIA), the peak intensity detectors, the Time-Of-Flight (TOF) detectors, and the multiplexers for read-out. This device has the feature in its detection ability for the small signal by optimizing the peak intensity detection circuit. By combining these devices with the one dimensional fast scanner, the real-time 3D range image can be obtained. After the explanations about the key devices, some 3D imaging results are demonstrated using the single element key devices. The imaging using the developed array devices is planned in the near future.

  18. Prenatal diagnosis of chromosomal abnormalities using array-based comparative genomic hybridization

    Technology Transfer Automated Retrieval System (TEKTRAN)

    This study was designed to evaluate the feasibility of using a targeted array-CGH strategy for prenatal diagnosis of genomic imbalances in a clinical setting of current pregnancies. Women undergoing prenatal diagnosis were counseled and offered array-CGH (BCM V4.0) in addition to routine chromosome ...

  19. 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.

  20. 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. PMID:27353347

  1. A hybrid antenna array design for 3-d direction of arrival estimation.

    PubMed

    Saqib, Najam-Us; Khan, Imdad

    2015-01-01

    A 3-D beam scanning antenna array design is proposed that gives a whole 3-D spherical coverage and also suitable for various radar and body-worn devices in the Body Area Networks applications. The Array Factor (AF) of the proposed antenna is derived and its various parameters like directivity, Half Power Beam Width (HPBW) and Side Lobe Level (SLL) are calculated by varying the size of the proposed antenna array. Simulations were carried out in MATLAB 2012b. The radiators are considered isotropic and hence mutual coupling effects are ignored. The proposed array shows a considerable improvement against the existing cylindrical and coaxial cylindrical arrays in terms of 3-D scanning, size, directivity, HPBW and SLL. PMID:25790103

  2. A novel imaging technique for structural health monitoring using sparse and compact arrays

    NASA Astrophysics Data System (ADS)

    Masson, Patrice; Quaegebeur, Nicolas; Demers, Dominique L.

    2011-04-01

    In the present paper, a technique called Excitelet is presented for the imaging of damages in thin-walled structures using the correlation of the measured signals with dispersed versions of the excitation signal. Piezoceramic (PZT) actuators are used to generate burst Lamb waves which interact with defects in metallic structures and the measurement is taken using sparse and compact array configurations of PZT sensors. The sparse sensing configuration consists of individual circular PZT elements distributed over the plate while the compact array configuration consists of a linear arrangement of sensors micro-machined on a single piece of bulk PZT wafer. This approach is presented as an extension of the classical imaging techniques and takes advantage of the chirplet-based matching pursuit algorithm. The approach is investigated experimentally on a 1.54 mm thick aluminum plate and comparison with existing Embedded Ultrasonic Structural Radar (EUSR) algorithm is performed for A0 and S0 modes for two frequency ranges of interest (centered at 150 kHz and 550 kHz). Damages are simulated using stacked magnets at different locations on the plate. Significant improvement of imaging quality is demonstrated with respect to existing imaging techniques based on group velocity and Time-of-Flight (ToF), for both sparse and compact PZT array configurations. Multimodal imaging strategies are presented to improve the imaging results. Moreover, it is shown that the proposed imaging technique provide accurate results in the case of dispersive propagation, while existing imaging techniques are no longer applicable.

  3. Colloidal quantum dot Vis-SWIR imaging: demonstration of a focal plane array and camera prototype (Presentation Recording)

    NASA Astrophysics Data System (ADS)

    Klem, Ethan J. D.; Gregory, Christopher W.; Temple, Dorota S.; Lewis, Jay S.

    2015-08-01

    RTI has developed a photodiode technology based on solution-processed PbS colloidal quantum dots (CQD). These devices are capable of providing low-cost, high performance detection across the Vis-SWIR spectral range. At the core of this technology is a heterojunction diode structure fabricated using techniques well suited to wafer-scale fabrication, such as spin coating and thermal evaporation. This enables RTI's CQD diodes to be processed at room temperature directly on top of read-out integrated circuits (ROIC), without the need for the hybridization step required by traditional SWIR detectors. Additionally, the CQD diodes can be fabricated on ROICs designed for other detector material systems, effectively allowing rapid prototype demonstrations of CQD focal plane arrays at low cost and on a wide range of pixel pitches and array sizes. We will show the results of fabricating CQD arrays directly on top of commercially available ROICs. Specifically, the ROICs are a 640 x 512 pixel format with 15 µm pitch, originally developed for InGaAs detectors. We will show that minor modifications to the surface of these ROICs make them suitable for use with our CQD detectors. Once completed, these FPAs are then assembled into a demonstration camera and their imaging performance is evaluated. In addition, we will discuss recent advances in device architecture and processing resulting in devices with room temperature dark currents of 2-5 nA/cm^2 and sensitivity from 350 nm to 1.7 μm. This combination of high performance, dramatic cost reduction, and multi-band sensitivity is ideally suited to expand the use of SWIR imaging in current applications, as well as to address applications which require a multispectral sensitivity not met by existing technologies.

  4. 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. PMID:21851844

  5. Hybrid Magnetic Nanostructures (MNS) for Magnetic Resonance Imaging Applications

    PubMed Central

    De, Mrinmoy; Chou, Stanley S.; Joshi, Hrushikesh M.

    2011-01-01

    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 R1 or R2 sensitivities, there has also been a boon in the development of agents covering more than one mode of detection. These include T1-PET, T2-PET T1-optical, T2-optical, T1–T2 agents and many others. In this review, we describe four areas which we feel have experienced particular growth due to nanotechnology, specifically T2 magnetic nanostructure development, T1/T2-optical dual mode agents, and most recently the T1–T2 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 T2 materials, its surface functionalization and coupling with optical and/or T1 agents. PMID:21851844

  6. Extraordinary transmission-based super-resolved axial imaging using subwavelength metallic nanoaperture arrays

    NASA Astrophysics Data System (ADS)

    Lee, Wonju; Oh, Youngjin; Choi, Jong-ryul; Kim, Kyujung; Kim, Donghyun

    2015-03-01

    A super-resolved axial imaging technique was investigated based on extraordinary transmission (EOT) of light using metallic gradient nanoaperture arrays. Light through subwavelength nanoapertures at thick metal film can be transmitted and amplified by several orders of magnitude due to plasmonic coupling. Here, the feasibility of EOT-based axial imaging with super resolution is explored. Since light penetration of EOT is much deeper than that of evanescent waves, the axial range to obtain the distance information of fluorescence signals can be extended by EOT. The axial distribution of ganglioside in mouse macrophage cells was measured with sub-diffraction-limited resolution after reconstruction using differential fluorescence excitation on gradient aperture arrays.

  7. 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

  8. 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.

  9. 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.

  10. 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.

  11. Prototype high detective quantum efficiency imaging panel based on a fiber-optic scintillation glass array (FOSGA) for megavoltage imaging

    NASA Astrophysics Data System (ADS)

    Samant, Sanjiv; Baciak, Jim; Gopal, Arun

    2011-09-01

    Megavoltage imaging has applications in nondestructive imaging for homeland security, radiotherapy, and industrial manufacturing. Current commercial systems are limited by low image quality as measured by detective quantum efficiency (DQE). These systems yield measured DQE=0.01-0.02, limiting efficacy for detection based on automated signal processing. Past efforts to improve DQE have included novel scintillators and manufacturing of large crystal structures. An alternative novel design for a 2D x-ray imager, based on a modification of existing amorphous silicon (a:Si) or flat-panel imagers, is presented. The panel utilizes a fiber-optic scintillation glass array (FOSGA) consisting of scintillation fibers bundled within a pixilated thick sintered tungsten housing. The tungsten housing is constructed using a lithographic manufacturing technique for high fabrication accuracy. The Tb-doped fibers emit light in the 555-565nm range (matched to the sensitive region of current a:Si photodiodes), with a decay time of 2ms (100-to-40%). Monte Carlo simulations, linear cascaded systems analyses, and film studies have been carried out to validate and optimize image quality for radiation beams in the 1-6MV range. An 8cmx8cm prototype array was fabricated using Tb-doped fibers (9mm length, 0.9mm diameter) loaded into a tungsten matrix (1.1mm pixel pitch, 0.1mm septa), yielding measured DQE=0.05 (vs theoretical DQE=0.07) for 6MV imaging , an order of magnitude improvement in image quality over current commercial imagers. Design parameters of a large field-of-view FOSGA imager for cargo container security imaging are presented: 5cm thick FOSGA array, 0.4-1mm pixel pitch, 50-70% fill factor, DQE>0.2 for 1-6MV range.

  12. 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.

  13. 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.

  14. 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.

  15. Towards a cellular multi-parameter analysis platform: fluorescence in situ hybridization (FISH) on microhole-array chips.

    PubMed

    Kurz, Christian M; Moosdijk, Stefan V D; Thielecke, Hagen; Velten, Thomas

    2011-01-01

    Highly-sensitive analysis systems based on cellular multi-parameter are needed in the diagnostics. Therefore we improved our previously developed chip platform for another additional analysis method, the fluorescence in situ hybridization. Fluorescence in situ hybridization (FISH) is a technique used in the diagnostics to determine the localization and the presence or absence of specific DNA sequence. To improve this labor- and cost-intensive method, we reduced the assay consumption by a factor of 5 compared to the standard protocol. Microhole chips were used for making the cells well addressable. The chips were fabricated by semiconductor technology on the basis of a Silicon wafer with a thin deposited silicon nitride layer (Si(3)N(4)). Human retina pigment epithelia (ARPE-19) cells were arrayed on 5-μm holes of a 35 × 35 microhole-array by a gently negative differential pressure of around 5 mbar. After 3 hours of incubation the cells were attached to the chip and the FISH protocol was applied to the positioned cells. A LabView software was developed to simplify the analysis. The software automatically counts the number of dots (positive labeled chromosome regions) as well as the distance between adjacent dots. Our developed platform reduces the assay consumption and the labor time. Furthermore, during the 3 hours of incubation non-invasive or minimal-invasive methods like Raman- and impedance-spectroscopy can be applied. PMID:22256298

  16. 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.

  17. 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.

  18. Photoacoustic imaging for deep targets in the breast using a multichannel 2D array transducer

    NASA Astrophysics Data System (ADS)

    Xie, Zhixing; Wang, Xueding; Morris, Richard F.; Padilla, Frederic R.; Lecarpentier, Gerald L.; Carson, Paul L.

    2011-03-01

    A photoacoustic (PA) imaging system was developed to achieve high sensitivity for the detection and characterization of vascular anomalies in the breast in the mammographic geometry. Signal detection from deep in the breast was achieved by a broadband 2D PVDF planar array that has a round shape with one side trimmed straight to improve fit near the chest wall. This array has 572 active elements and a -6dB bandwidth of 0.6-1.7 MHz. The low frequency enhances imaging depth and increases the size of vascular collections displayed without edge enhancement. The PA signals from all the elements go through low noise preamplifiers in the probe that are very close to the array elements for optimized noise control. Driven by 20 independent on-probe signal processing channels, imaging with both high sensitivity and good speed was achieved. To evaluate the imaging depth and the spatial resolution of this system,2.38mm I.D. artificial vessels embedded deeply in ex vivo breasts harvested from fresh cadavers and a 3mm I.D. tube in breast mimicking phantoms made of pork loin and fat tissues were imaged. Using near-infrared laser light with incident energy density within the ANSI safety limit, imaging depths of up to 49 mm in human breasts and 52 mm in phantoms were achieved. With a high power tunable laser working on multiple wavelengths, this system might contribute to 3D noninvasive imaging of morphological and physiological tissue features throughout the breast.

  19. Imaging through a convex interface with unknown position and shape using an ultrasonic linear array

    NASA Astrophysics Data System (ADS)

    Matuda, Marcelo Y.; Buiochi, Flávio; Adamowski, Julio C.

    2012-05-01

    This paper presents a technique for improving the internal imaging of a solid object immersed in water using an ultrasonic array. This technique consists in determining the position and shape of a convex object surface using a combination of synthetic transmit aperture (STA) and sign coherence factor (SCF) methods. The SCF attenuates the grating lobe noise. The technique is applied to a cylindrical aluminium object with internal holes simulating defects. The first step is the acquisition of a sequence of STA images with SCF, using a distinct group of adjacent array elements for each image. In the second step, a circle is fitted to the positions of the peak values in each image. Finally, using the Fermat's principle and this circle as the interface between the water and the metallic object, the propagation delays from the array elements to the image grid points may be calculated and used in another STA image. In this final image, the small holes in the cylindrical object can clearly be identified. The effects of the SCF for a large diameter circular reflector are simulated and compared with experimental data.

  20. 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

  1. 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.

  2. 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.

  3. 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.

  4. Multi-Echo Segmented k-space Imaging: An Optimized Hybrid Sequence for Ultrafast Cardiac Imaging

    PubMed Central

    Reeder, Scott B.; Atalar, Ergin; Faranesh, Anthony Z.; McVeigh, Elliot R.

    2007-01-01

    Cardiac magnetic resonance imaging requires high temporal resolution to resolve motion and contrast uptake with low total scan times to avoid breathing artifacts. While spoiled gradient echo (SPGR) imaging is robust and reproducible, it is relatively inefficient and requires long breath-holds to acquire high time resolution movies of the heart. Echo planar imaging (EPI) is highly efficient with excellent signal-to-noise ratio (SNR) behavior; however, it is particularly difficult to use in the heart because of its sensitivity to chemical shift, susceptibility, and motion. EPI may also require reference scans, which are used to measure hardware delays and phase offsets that cause ghosting artifacts; these reference scans are more difficult and less reliable in the heart. Consequently, a hybrid EPI/SPGR sequence is proposed for application to rapid cardiac imaging. A detailed optimization of SNR and echo train length for multi-echo sequences is presented. It is shown that significant reductions in total scan time are possible while maintaining good image quality. This will allow complete motion sampling of the entire heart in one to three breath-holds, necessary for MR cardiac dobutamine stress testing. Improved speed performance also permits sampling of three to six slices every heartbeat for bolus injection perfusion studies. PMID:10080287

  5. 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.

  6. 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. PMID:26119418

  7. 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.

  8. Fast, Deep-Record-Length, Fiber-Coupled Photodiode Imaging Array for Plasma Diagnostics

    NASA Astrophysics Data System (ADS)

    Brockington, Samuel; Case, Andrew; Witherspoon, F. Douglas

    2014-10-01

    HyperV Technologies has been developing an imaging diagnostic comprised of an array of fast, low-cost, long-record-length, fiber-optically-coupled photodiode channels to investigate plasma dynamics and other fast, bright events. By coupling an imaging fiber bundle to a bank of amplified photodiode channels, imagers and streak imagers of 100 to 1000 pixels can be constructed. By interfacing analog photodiode systems directly to commercial analog-to-digital converters and modern memory chips, a prototype 100 pixel array with an extremely deep record length (128 k points at 20 Msamples/s) and 10 bit pixel resolution has already been achieved. HyperV now seeks to extend these techniques to construct a prototype 1000 Pixel framing camera with up to 100 Msamples/sec rate and 10 to 12 bit depth. Preliminary experimental results as well as Phase 2 plans will be discussed. Work supported by USDOE Phase 2 SBIR Grant DE-SC0009492.

  9. 128x96 pixel field emitter-array image sensor with HARP target

    NASA Astrophysics Data System (ADS)

    Yamagishi, Toshio; Nanba, Masakazu; Osada, Katsunori; Takiguchi, Yoshiro; Okazaki, Saburo; Egami, Norifumi; Tanioka, Kenkichi; Tanaka, Mitsuru; Itoh, Shigeo

    2002-04-01

    In pursuit of developing a next-generation pick-up device having high definition and ultrahigh sensitivity features, research continues on a new type of image sensor that combines a HARP target and a field emitter array. A new field emitter array on a small-sized substrate is designed and a unique packaging technique is proposed. The prototype device is sealed in a vacuum package with a thickness of only about 10 mm and has 128 horizontal and 96 vertical pixels. Experimental results show that images could be successfully reproduced for the first time ever in a device of this type. Highly sensitive characteristics and propr resolution were also obtained with the device. The prototype image sensor can operate stably for more than 250 hours, demonstrating its feasibility and potential as a next- generation image pickup device.

  10. 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.

  11. 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.

  12. 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.

  13. A liquid crystal microlens array with aluminum and graphene electrodes for plenoptic imaging

    NASA Astrophysics Data System (ADS)

    Lei, Yu; Tong, Qing; Luo, Jun; Zhang, Xinyu; Sang, Hongshi; Xie, Changsheng

    2015-12-01

    Currently, several semiconducting oxide materials such as typical indium tin oxide are widely used as the transparent conducting electrodes (TCEs) in liquid crystal microlens arrays. In this paper, we fabricate a liquid crystal microlens array using graphene rather than semiconducting oxides as the TCE. Common optical experiments are carried out to acquire the focusing features of the graphene-based liquid crystal microlens array (GLCMLA) driven electrically. The acquired optical fields show that the GLCMLA can converge incident collimating lights efficiently. The relationship between the focal length and the applied voltage signal is presented. Then the GLCMLA is deployed in a plenoptic camera prototype and the raw images are acquired so as to verify their imaging capability. Our experiments demonstrate that graphene has already presented a broad application prospect in the area of adaptive optics.

  14. Efficiency improvement and image quality of organic light-emitting display by attaching cylindrical microlens arrays.

    PubMed

    Lee, Jiun-Haw; Ho, Yu-Hsuan; Chen, Kuan-Yu; Lin, Hoang-Yan; Fang, Jheng-Hao; Hsu, Sheng-Chih; Lin, Jia-Rong; Wei, Mao-Kuo

    2008-12-22

    In this paper, cylindrical microlens arrays with two different alignments were proposed to be applied in a commercial mobile phone having an organic light-emitting diode (OLED) panel. It was found that the parallel-aligned cylindrical array had better performance than the vertical-aligned one for the OLED panel. The parallel-aligned cylindrical microlens array can increase the luminous current efficiency at surface normal and the luminous power efficiency of the OLED panel by 45% and 38%, respectively. Besides, it can also make the spectrum of the OLED panel more insensitive to the viewing angle. Though it can slightly blur the image on the OLED panel, the universal image quality index can be maintained at a level of 0.8630. PMID:19104547

  15. 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. PMID:26405923

  16. Partially coherent analysis of imaging and interferometric phased arrays: noise, correlations, and fluctuations.

    PubMed

    Withington, Stafford; Saklatvala, George; Hobson, Michael P

    2006-06-01

    Phased arrays are of considerable importance for far-infrared, submillimeter-wave, and microwave astronomy; they are also being developed for areas as diverse as optical switching, radar, and radio communications. We present a discretized, modal theory of imaging and interferometric phased arrays. It is shown that the average powers, field correlations, power fluctuations, and correlations between power fluctuations at the output ports of an imaging, or interferometric, phased array can be determined for a source in any state of spatial coherence and polarization, once the synthesized beam patterns are known. It is not necessary to know anything about the internal construction of the beam-forming networks; indeed, the beam patterns can be taken from experimental data. The synthesized beams can be nonorthogonal and even linearly dependent. Our theory leads to many conceptual insights and opens the way to a range of new design and simulation techniques. PMID:16715152

  17. 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.

  18. 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. PMID:25216300

  19. 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.

  20. SNR-optimality of sum-of-squares reconstruction for phased-array magnetic resonance imaging.

    PubMed

    Larsson, Erik G; Erdogmus, Deniz; Yan, Rui; Principe, Jose C; Fitzsimmons, Jeffrey R

    2003-07-01

    We consider the commonly used "Sum-of-Squares" (SoS) reconstruction method for phased-array magnetic resonance imaging with unknown coil sensitivities. We show that the signal-to-noise ratio (SNR) in the image produced by SoS is asymptotically (as the input SNR--> infinity ) equal to that of maximum-ratio combining, which is the best unbiased reconstruction method when the coil sensitivities are known. Finally, we discuss the implications of this result. PMID:12852915