Intraoperative Imaging Guidance for Sentinel Node Biopsy in Melanoma Using a Mobile Gamma Camera

DOE Office of Scientific and Technical Information (OSTI.GOV)

Dengel, Lynn T; Judy, Patricia G; Petroni, Gina R

2011-04-01

The objective is to evaluate the sensitivity and clinical utility of intraoperative mobile gamma camera (MGC) imaging in sentinel lymph node biopsy (SLNB) in melanoma. The false-negative rate for SLNB for melanoma is approximately 17%, for which failure to identify the sentinel lymph node (SLN) is a major cause. Intraoperative imaging may aid in detection of SLN near the primary site, in ambiguous locations, and after excision of each SLN. The present pilot study reports outcomes with a prototype MGC designed for rapid intraoperative image acquisition. We hypothesized that intraoperative use of the MGC would be feasible and that sensitivitymore » would be at least 90%. From April to September 2008, 20 patients underwent Tc99 sulfur colloid lymphoscintigraphy, and SLNB was performed with use of a conventional fixed gamma camera (FGC), and gamma probe followed by intraoperative MGC imaging. Sensitivity was calculated for each detection method. Intraoperative logistical challenges were scored. Cases in which MGC provided clinical benefit were recorded. Sensitivity for detecting SLN basins was 97% for the FGC and 90% for the MGC. A total of 46 SLN were identified: 32 (70%) were identified as distinct hot spots by preoperative FGC imaging, 31 (67%) by preoperative MGC imaging, and 43 (93%) by MGC imaging pre- or intraoperatively. The gamma probe identified 44 (96%) independent of MGC imaging. The MGC provided defined clinical benefit as an addition to standard practice in 5 (25%) of 20 patients. Mean score for MGC logistic feasibility was 2 on a scale of 1-9 (1 = best). Intraoperative MGC imaging provides additional information when standard techniques fail or are ambiguous. Sensitivity is 90% and can be increased. This pilot study has identified ways to improve the usefulness of an MGC for intraoperative imaging, which holds promise for reducing false negatives of SLNB for melanoma.« less

Advances in Gamma-Ray Imaging with Intensified Quantum-Imaging Detectors

NASA Astrophysics Data System (ADS)

Han, Ling

Nuclear medicine, an important branch of modern medical imaging, is an essential tool for both diagnosis and treatment of disease. As the fundamental element of nuclear medicine imaging, the gamma camera is able to detect gamma-ray photons emitted by radiotracers injected into a patient and form an image of the radiotracer distribution, reflecting biological functions of organs or tissues. Recently, an intensified CCD/CMOS-based quantum detector, called iQID, was developed in the Center for Gamma-Ray Imaging. Originally designed as a novel type of gamma camera, iQID demonstrated ultra-high spatial resolution (< 100 micron) and many other advantages over traditional gamma cameras. This work focuses on advancing this conceptually-proven gamma-ray imaging technology to make it ready for both preclinical and clinical applications. To start with, a Monte Carlo simulation of the key light-intensification device, i.e. the image intensifier, was developed, which revealed the dominating factor(s) that limit energy resolution performance of the iQID cameras. For preclinical imaging applications, a previously-developed iQID-based single-photon-emission computed-tomography (SPECT) system, called FastSPECT III, was fully advanced in terms of data acquisition software, system sensitivity and effective FOV by developing and adopting a new photon-counting algorithm, thicker columnar scintillation detectors, and system calibration method. Originally designed for mouse brain imaging, the system is now able to provide full-body mouse imaging with sub-350-micron spatial resolution. To further advance the iQID technology to include clinical imaging applications, a novel large-area iQID gamma camera, called LA-iQID, was developed from concept to prototype. Sub-mm system resolution in an effective FOV of 188 mm x 188 mm has been achieved. The camera architecture, system components, design and integration, data acquisition, camera calibration, and performance evaluation are presented in

The HURRA filter: An easy method to eliminate collimator artifacts in high-energy gamma camera images.

PubMed

Perez-Garcia, H; Barquero, R

The correct determination and delineation of tumor/organ size is crucial in 2-D imaging in 131 I therapy. These images are usually obtained using a system composed of a Gamma camera and high-energy collimator, although the system can produce artifacts in the image. This article analyses these artifacts and describes a correction filter that can eliminate those collimator artifacts. Using free software, ImageJ, a central profile in the image is obtained and analyzed. Two components can be seen in the fluctuation of the profile: one associated with the stochastic nature of the radiation, plus electronic noise and the other periodically across the position in space due to the collimator. These frequencies are analytically obtained and compared with the frequencies in the Fourier transform of the profile. A specially developed filter removes the artifacts in the 2D Fourier transform of the DICOM image. This filter is tested using a 15-cm-diameter Petri dish with 131 I radioactive water (big object size) image, a 131 I clinical pill (small object size) image, and an image of the remainder of the lesion of two patients treated with 3.7GBq (100mCi), and 4.44GBq (120mCi) of 131 I, respectively, after thyroidectomy. The artifact is due to the hexagonal periodic structure of the collimator. The use of the filter on large-sized images reduces the fluctuation by 5.8-3.5%. In small-sized images, the FWHM can be determined in the filtered image, while this is impossible in the unfiltered image. The definition of tumor boundary and the visualization of the activity distribution inside patient lesions improve drastically when the filter is applied to the corresponding images obtained with HE gamma camera. The HURRA filter removes the artifact of high-energy collimator artifacts in planar images obtained with a Gamma camera without reducing the image resolution. It can be applied in any study of patient quantification because the number of counts remains invariant. The filter makes

Optimizing a three-stage Compton camera for measuring prompt gamma rays emitted during proton radiotherapy

PubMed Central

Peterson, S W; Robertson, D; Polf, J

2011-01-01

In this work, we investigate the use of a three-stage Compton camera to measure secondary prompt gamma rays emitted from patients treated with proton beam radiotherapy. The purpose of this study was (1) to develop an optimal three-stage Compton camera specifically designed to measure prompt gamma rays emitted from tissue and (2) to determine the feasibility of using this optimized Compton camera design to measure and image prompt gamma rays emitted during proton beam irradiation. The three-stage Compton camera was modeled in Geant4 as three high-purity germanium detector stages arranged in parallel-plane geometry. Initially, an isotropic gamma source ranging from 0 to 15 MeV was used to determine lateral width and thickness of the detector stages that provided the optimal detection efficiency. Then, the gamma source was replaced by a proton beam irradiating a tissue phantom to calculate the overall efficiency of the optimized camera for detecting emitted prompt gammas. The overall calculated efficiencies varied from ~10−6 to 10−3 prompt gammas detected per proton incident on the tissue phantom for several variations of the optimal camera design studied. Based on the overall efficiency results, we believe it feasible that a three-stage Compton camera could detect a sufficient number of prompt gammas to allow measurement and imaging of prompt gamma emission during proton radiotherapy. PMID:21048295

Acquisition of gamma camera and physiological data by computer.

PubMed

Hack, S N; Chang, M; Line, B R; Cooper, J A; Robeson, G H

1986-11-01

We have designed, implemented, and tested a new Research Data Acquisition System (RDAS) that permits a general purpose digital computer to acquire signals from both gamma camera sources and physiological signal sources concurrently. This system overcomes the limited multi-source, high speed data acquisition capabilities found in most clinically oriented nuclear medicine computers. The RDAS can simultaneously input signals from up to four gamma camera sources with a throughput of 200 kHz per source and from up to eight physiological signal sources with an aggregate throughput of 50 kHz. Rigorous testing has found the RDAS to exhibit acceptable linearity and timing characteristics. In addition, flood images obtained by this system were compared with flood images acquired by a commercial nuclear medicine computer system. National Electrical Manufacturers Association performance standards of the flood images were found to be comparable.

Feasibility of a high-speed gamma-camera design using the high-yield-pileup-event-recovery method.

PubMed

Wong, W H; Li, H; Uribe, J; Baghaei, H; Wang, Y; Yokoyama, S

2001-04-01

Higher count-rate gamma cameras than are currently used are needed if the technology is to fulfill its promise in positron coincidence imaging, radionuclide therapy dosimetry imaging, and cardiac first-pass imaging. The present single-crystal design coupled with conventional detector electronics and the traditional Anger-positioning algorithm hinder higher count-rate imaging because of the pileup of gamma-ray signals in the detector and electronics. At an interaction rate of 2 million events per second, the fraction of nonpileup events is < 20% of the total incident events. Hence, the recovery of pileup events can significantly increase the count-rate capability, increase the yield of imaging photons, and minimize image artifacts associated with pileups. A new technology to significantly enhance the performance of gamma cameras in this area is introduced. We introduce a new electronic design called high-yield-pileup-event-recovery (HYPER) electronics for processing the detector signal in gamma cameras so that the individual gamma energies and positions of pileup events, including multiple pileups, can be resolved and recovered despite the mixing of signals. To illustrate the feasibility of the design concept, we have developed a small gamma-camera prototype with the HYPER-Anger electronics. The camera has a 10 x 10 x 1 cm NaI(Tl) crystal with four photomultipliers. Hot-spot and line sources with very high 99mTc activities were imaged. The phantoms were imaged continuously from 60,000 to 3,500,000 counts per second to illustrate the efficacy of the method as a function of counting rates. At 2-3 million events per second, all phantoms were imaged with little distortion, pileup, and dead-time loss. At these counting rates, multiple pileup events (> or = 3 events piling together) were the predominate occurrences, and the HYPER circuit functioned well to resolve and recover these events. The full width at half maximum of the line-spread function at 3,000,000 counts per

Development of an all-in-one gamma camera/CCD system for safeguard verification

NASA Astrophysics Data System (ADS)

Kim, Hyun-Il; An, Su Jung; Chung, Yong Hyun; Kwak, Sung-Woo

2014-12-01

For the purpose of monitoring and verifying efforts at safeguarding radioactive materials in various fields, a new all-in-one gamma camera/charged coupled device (CCD) system was developed. This combined system consists of a gamma camera, which gathers energy and position information on gamma-ray sources, and a CCD camera, which identifies the specific location in a monitored area. Therefore, 2-D image information and quantitative information regarding gamma-ray sources can be obtained using fused images. A gamma camera consists of a diverging collimator, a 22 × 22 array CsI(Na) pixelated scintillation crystal with a pixel size of 2 × 2 × 6 mm3 and Hamamatsu H8500 position-sensitive photomultiplier tube (PSPMT). The Basler scA640-70gc CCD camera, which delivers 70 frames per second at video graphics array (VGA) resolution, was employed. Performance testing was performed using a Co-57 point source 30 cm from the detector. The measured spatial resolution and sensitivity were 4.77 mm full width at half maximum (FWHM) and 7.78 cps/MBq, respectively. The energy resolution was 18% at 122 keV. These results demonstrate that the combined system has considerable potential for radiation monitoring.

The Advanced Gamma-ray Imaging System (AGIS): Camera Electronics Designs

NASA Astrophysics Data System (ADS)

Tajima, Hiroyasu; Buckley, J.; Byrum, K.; Drake, G.; Falcone, A.; Funk, S.; Holder, J.; Horan, D.; Krawczynski, H.; Ong, R.; Swordy, S.; Wagner, R.; Wakely, S.; Williams, D.; Camera Electronics Working Group; AGIS Collaboration

2008-03-01

AGIS, a next generation of atmospheric Cherenkov telescope arrays, aims to achieve a sensitivity level of a milliCrab for gamma-ray observations in in the energy band of 40 GeV to 100 TeV. Such improvement requires cost reduction of individual components with high reliability in order to equip the order of 100 telescopes necessary to achieve the sensitivity goal. We are exploring several design concepts to reduce the cost of camera electronics while improving their performance. These design concepts include systems based on multi-channel waveform sampling ASIC optimized for AGIS, a system based on IIT (image intensifier tube) for large channel (order of 1 million channels) readout as well as a multiplexed FADC system based on the current VERITAS readout design. Here we present trade-off studies of these design concepts.

The Advanced Gamma-ray Imaging System (AGIS): Camera Electronics Designs

NASA Astrophysics Data System (ADS)

Tajima, H.; Buckley, J.; Byrum, K.; Drake, G.; Falcone, A.; Funk, S.; Holder, J.; Horan, D.; Krawczynski, H.; Ong, R.; Swordy, S.; Wagner, R.; Williams, D.

2008-04-01

AGIS, a next generation of atmospheric Cherenkov telescope arrays, aims to achieve a sensitivity level of a milliCrab for gamma-ray observations in the energy band of 40 GeV to 100 TeV. Such improvement requires cost reduction of individual components with high reliability in order to equip the order of 100 telescopes necessary to achieve the sensitivity goal. We are exploring several design concepts to reduce the cost of camera electronics while improving their performance. These design concepts include systems based on multi-channel waveform sampling ASIC optimized for AGIS, a system based on IIT (image intensifier tube) for large channel (order of 1 million channels) readout as well as a multiplexed FADC system based on the current VERITAS readout design. Here we present trade-off in the studies of these design concepts.

Precision imaging of 4.4 MeV gamma rays using a 3-D position sensitive Compton camera.

PubMed

Koide, Ayako; Kataoka, Jun; Masuda, Takamitsu; Mochizuki, Saku; Taya, Takanori; Sueoka, Koki; Tagawa, Leo; Fujieda, Kazuya; Maruhashi, Takuya; Kurihara, Takuya; Inaniwa, Taku

2018-05-25

Imaging of nuclear gamma-ray lines in the 1-10 MeV range is far from being established in both medical and physical applications. In proton therapy, 4.4 MeV gamma rays are emitted from the excited nucleus of either 12 C* or 11 B* and are considered good indicators of dose delivery and/or range verification. Further, in gamma-ray astronomy, 4.4 MeV gamma rays are produced by cosmic ray interactions in the interstellar medium, and can thus be used to probe nucleothynthesis in the universe. In this paper, we present a high-precision image of 4.4 MeV gamma rays taken by newly developed 3-D position sensitive Compton camera (3D-PSCC). To mimic the situation in proton therapy, we first irradiated water, PMMA and Ca(OH)2 with a 70 MeV proton beam, then we identified various nuclear lines with the HPGe detector. The 4.4 MeV gamma rays constitute a broad peak, including single and double escape peaks. Thus, by setting an energy window of 3D-PSCC from 3 to 5 MeV, we show that a gamma ray image sharply concentrates near the Bragg peak, as expected from the minimum energy threshold and sharp peak profile in the cross section of 12 C(p,p) 12 C*.

Neutron Imaging Camera

NASA Technical Reports Server (NTRS)

Hunter, Stanley; deNolfo, G. A.; Barbier, L. M.; Link, J. T.; Son, S.; Floyd, S. R.; Guardala, N.; Skopec, M.; Stark, B.

2008-01-01

The Neutron Imaging Camera (NIC) is based on the Three-dimensional Track Imager (3DTI) technology developed at GSFC for gamma-ray astrophysics applications. The 3-DTI, a large volume time-projection chamber, provides accurate, approximately 0.4 mm resolution, 3-D tracking of charged particles. The incident direction of fast neutrons, En > 0.5 MeV, are reconstructed from the momenta and energies of the proton and triton fragments resulting from (sup 3)He(n,p) (sup 3)H interactions in the 3-DTI volume. The performance of the NIC from laboratory and accelerator tests is presented.

Test of Compton camera components for prompt gamma imaging at the ELBE bremsstrahlung beam

NASA Astrophysics Data System (ADS)

Hueso-González, F.; Golnik, C.; Berthel, M.; Dreyer, A.; Enghardt, W.; Fiedler, F.; Heidel, K.; Kormoll, T.; Rohling, H.; Schöne, S.; Schwengner, R.; Wagner, A.; Pausch, G.

2014-05-01

In the context of ion beam therapy, particle range verification is a major challenge for the quality assurance of the treatment. One approach is the measurement of the prompt gamma rays resulting from the tissue irradiation. A Compton camera based on several position sensitive gamma ray detectors, together with an imaging algorithm, is expected to reconstruct the prompt gamma ray emission density map, which is correlated with the dose distribution. At OncoRay and Helmholtz-Zentrum Dresden-Rossendorf (HZDR), a Compton camera setup is being developed consisting of two scatter planes: two CdZnTe (CZT) cross strip detectors, and an absorber consisting of one Lu2SiO5 (LSO) block detector. The data acquisition is based on VME electronics and handled by software developed on the ROOT framework. The setup has been tested at the linear electron accelerator ELBE at HZDR, which is used in this experiment to produce bunched bremsstrahlung photons with up to 12.5 MeV energy and a repetition rate of 13 MHz. Their spectrum has similarities with the shape expected from prompt gamma rays in the clinical environment, and the flux is also bunched with the accelerator frequency. The charge sharing effect of the CZT detector is studied qualitatively for different energy ranges. The LSO detector pixel discrimination resolution is analyzed and it shows a trend to improve for high energy depositions. The time correlation between the pulsed prompt photons and the measured detector signals, to be used for background suppression, exhibits a time resolution of 3 ns FWHM for the CZT detector and of 2 ns for the LSO detector. A time walk correction and pixel-wise calibration is applied for the LSO detector, whose resolution improves up to 630 ps. In conclusion, the detector setup is suitable for time-resolved background suppression in pulsed clinical particle accelerators. Ongoing tasks are the quantitative comparison with simulations and the test of imaging algorithms. Experiments at proton

Performance evaluation for pinhole collimators of small gamma camera by MTF and NNPS analysis: Monte Carlo simulation study

NASA Astrophysics Data System (ADS)

Jeon, Hosang; Kim, Hyunduk; Cha, Bo Kyung; Kim, Jong Yul; Cho, Gyuseong; Chung, Yong Hyun; Yun, Jong-Il

2009-06-01

Presently, the gamma camera system is widely used in various medical diagnostic, industrial and environmental fields. Hence, the quantitative and effective evaluation of its imaging performance is essential for design and quality assurance. The National Electrical Manufacturers Association (NEMA) standards for gamma camera evaluation are insufficient to perform sensitive evaluation. In this study, modulation transfer function (MTF) and normalized noise power spectrum (NNPS) will be suggested to evaluate the performance of small gamma camera with changeable pinhole collimators using Monte Carlo simulation. We simulated the system with a cylinder and a disk source, and seven different pinhole collimators from 1- to 4-mm-diameter pinhole with lead. The MTF and NNPS data were obtained from output images and were compared with full-width at half-maximum (FWHM), sensitivity and differential uniformity. In the result, we found that MTF and NNPS are effective and novel standards to evaluate imaging performance of gamma cameras instead of conventional NEMA standards.

A versatile calibration procedure for portable coded aperture gamma cameras and RGB-D sensors

NASA Astrophysics Data System (ADS)

Paradiso, V.; Crivellaro, A.; Amgarou, K.; de Lanaute, N. Blanc; Fua, P.; Liénard, E.

2018-04-01

The present paper proposes a versatile procedure for the geometrical calibration of coded aperture gamma cameras and RGB-D depth sensors, using only one radioactive point source and a simple experimental set-up. Calibration data is then used for accurately aligning radiation images retrieved by means of the γ-camera with the respective depth images computed with the RGB-D sensor. The system resulting from such a combination is thus able to retrieve, automatically, the distance of radioactive hotspots by means of pixel-wise mapping between gamma and depth images. This procedure is of great interest for a wide number of applications, ranging from precise automatic estimation of the shape and distance of radioactive objects to Augmented Reality systems. Incidentally, the corresponding results validated the choice of a perspective design model for a coded aperture γ-camera.

Development of gamma-photon/Cerenkov-light hybrid system for simultaneous imaging of I-131 radionuclide

NASA Astrophysics Data System (ADS)

Yamamoto, Seiichi; Suzuki, Mayumi; Kato, Katsuhiko; Watabe, Tadashi; Ikeda, Hayato; Kanai, Yasukazu; Ogata, Yoshimune; Hatazawa, Jun

2016-09-01

Although iodine 131 (I-131) is used for radionuclide therapy, high resolution images are difficult to obtain with conventional gamma cameras because of the high energy of I-131 gamma photons (364 keV). Cerenkov-light imaging is a possible method for beta emitting radionuclides, and I-131 (606 MeV maximum beta energy) is a candidate to obtain high resolution images. We developed a high energy gamma camera system for I-131 radionuclide and combined it with a Cerenkov-light imaging system to form a gamma-photon/Cerenkov-light hybrid imaging system to compare the simultaneously measured images of these two modalities. The high energy gamma imaging detector used 0.85-mm×0.85-mm×10-mm thick GAGG scintillator pixels arranged in a 44×44 matrix with a 0.1-mm thick reflector and optical coupled to a Hamamatsu 2 in. square position sensitive photomultiplier tube (PSPMT: H12700 MOD). The gamma imaging detector was encased in a 2 cm thick tungsten shield, and a pinhole collimator was mounted on its top to form a gamma camera system. The Cerenkov-light imaging system was made of a high sensitivity cooled CCD camera. The Cerenkov-light imaging system was combined with the gamma camera using optical mirrors to image the same area of the subject. With this configuration, we simultaneously imaged the gamma photons and the Cerenkov-light from I-131 in the subjects. The spatial resolution and sensitivity of the gamma camera system for I-131 were respectively 3 mm FWHM and 10 cps/MBq for the high sensitivity collimator at 10 cm from the collimator surface. The spatial resolution of the Cerenkov-light imaging system was 0.64 mm FWHM at 10 cm from the system surface. Thyroid phantom and rat images were successfully obtained with the developed gamma-photon/Cerenkov-light hybrid imaging system, allowing direct comparison of these two modalities. Our developed gamma-photon/Cerenkov-light hybrid imaging system will be useful to evaluate the advantages and disadvantages of these two

MO-AB-206-02: Testing Gamma Cameras Based On TG177 WG Report

DOE Office of Scientific and Technical Information (OSTI.GOV)

Halama, J.

2016-06-15

This education session will cover the physics and operation principles of gamma cameras and PET scanners. The first talk will focus on PET imaging. An overview of the principles of PET imaging will be provided, including positron decay physics, and the transition from 2D to 3D imaging. More recent advances in hardware and software will be discussed, such as time-of-flight imaging, and improvements in reconstruction algorithms that provide for options such as depth-of-interaction corrections. Quantitative applications of PET will be discussed, as well as the requirements for doing accurate quantitation. Relevant performance tests will also be described. Learning Objectives: Bemore » able to describe basic physics principles of PET and operation of PET scanners. Learn about recent advances in PET scanner hardware technology. Be able to describe advances in reconstruction techniques and improvements Be able to list relevant performance tests. The second talk will focus on gamma cameras. The Nuclear Medicine subcommittee has charged a task group (TG177) to develop a report on the current state of physics testing of gamma cameras, SPECT, and SPECT/CT systems. The report makes recommendations for performance tests to be done for routine quality assurance, annual physics testing, and acceptance tests, and identifies those needed satisfy the ACR accreditation program and The Joint Commission imaging standards. The report is also intended to be used as a manual with detailed instructions on how to perform tests under widely varying conditions. Learning Objectives: At the end of the presentation members of the audience will: Be familiar with the tests recommended for routine quality assurance, annual physics testing, and acceptance tests of gamma cameras for planar imaging. Be familiar with the tests recommended for routine quality assurance, annual physics testing, and acceptance tests of SPECT systems. Be familiar with the tests of a SPECT/CT system that include the CT

Evaluation of a CdTe semiconductor based compact gamma camera for sentinel lymph node imaging

DOE Office of Scientific and Technical Information (OSTI.GOV)

Russo, Paolo; Curion, Assunta S.; Mettivier, Giovanni

2011-03-15

Purpose: The authors assembled a prototype compact gamma-ray imaging probe (MediPROBE) for sentinel lymph node (SLN) localization. This probe is based on a semiconductor pixel detector. Its basic performance was assessed in the laboratory and clinically in comparison with a conventional gamma camera. Methods: The room-temperature CdTe pixel detector (1 mm thick) has 256x256 square pixels arranged with a 55 {mu}m pitch (sensitive area 14.08x14.08 mm{sup 2}), coupled pixel-by-pixel via bump-bonding to the Medipix2 photon-counting readout CMOS integrated circuit. The imaging probe is equipped with a set of three interchangeable knife-edge pinhole collimators (0.94, 1.2, or 2.1 mm effective diametermore » at 140 keV) and its focal distance can be regulated in order to set a given field of view (FOV). A typical FOV of 70 mm at 50 mm skin-to-collimator distance corresponds to a minification factor 1:5. The detector is operated at a single low-energy threshold of about 20 keV. Results: For {sup 99m}Tc, at 50 mm distance, a background-subtracted sensitivity of 6.5x10{sup -3} cps/kBq and a system spatial resolution of 5.5 mm FWHM were obtained for the 0.94 mm pinhole; corresponding values for the 2.1 mm pinhole were 3.3x10{sup -2} cps/kBq and 12.6 mm. The dark count rate was 0.71 cps. Clinical images in three patients with melanoma indicate detection of the SLNs with acquisition times between 60 and 410 s with an injected activity of 26 MBq {sup 99m}Tc and prior localization with standard gamma camera lymphoscintigraphy. Conclusions: The laboratory performance of this imaging probe is limited by the pinhole collimator performance and the necessity of working in minification due to the limited detector size. However, in clinical operative conditions, the CdTe imaging probe was effective in detecting SLNs with adequate resolution and an acceptable sensitivity. Sensitivity is expected to improve with the future availability of a larger CdTe detector permitting operation at

Developments in mercuric iodide gamma ray imaging

DOE Office of Scientific and Technical Information (OSTI.GOV)

Patt, B.E.; Beyerle, A.G.; Dolin, R.C.

A mercuric iodide gamma-ray imaging array and camera system previously described has been characterized for spatial and energy resolution. Based on this data a new camera is being developed to more fully exploit the potential of the array. Characterization results and design criterion for the new camera will be presented. 2 refs., 7 figs.

Development and calibration of a new gamma camera detector using large square Photomultiplier Tubes

NASA Astrophysics Data System (ADS)

Zeraatkar, N.; Sajedi, S.; Teimourian Fard, B.; Kaviani, S.; Akbarzadeh, A.; Farahani, M. H.; Sarkar, S.; Ay, M. R.

2017-09-01

Large area scintillation detectors applied in gamma cameras as well as Single Photon Computed Tomography (SPECT) systems, have a major role in in-vivo functional imaging. Most of the gamma detectors utilize hexagonal arrangement of Photomultiplier Tubes (PMTs). In this work we applied large square-shaped PMTs with row/column arrangement and positioning. The Use of large square PMTs reduces dead zones in the detector surface. However, the conventional center of gravity method for positioning may not introduce an acceptable result. Hence, the digital correlated signal enhancement (CSE) algorithm was optimized to obtain better linearity and spatial resolution in the developed detector. The performance of the developed detector was evaluated based on NEMA-NU1-2007 standard. The acquired images using this method showed acceptable uniformity and linearity comparing to three commercial gamma cameras. Also the intrinsic and extrinsic spatial resolutions with low-energy high-resolution (LEHR) collimator at 10 cm from surface of the detector were 3.7 mm and 7.5 mm, respectively. The energy resolution of the camera was measured 9.5%. The performance evaluation demonstrated that the developed detector maintains image quality with a reduced number of used PMTs relative to the detection area.

A prototype small CdTe gamma camera for radioguided surgery and other imaging applications.

PubMed

Tsuchimochi, Makoto; Sakahara, Harumi; Hayama, Kazuhide; Funaki, Minoru; Ohno, Ryoichi; Shirahata, Takashi; Orskaug, Terje; Maehlum, Gunnar; Yoshioka, Koki; Nygard, Einar

2003-12-01

Gamma probes have been used for sentinel lymph node biopsy in melanoma and breast cancer. However, these probes can provide only radioactivity counts and variable pitch audio output based on the intensity of the detected radioactivity. We have developed a small semiconductor gamma camera (SSGC) that allows visualisation of the size, shape and location of the target tissues. This study is designed to characterise the performance of the SSGC for radioguided surgery of metastatic lesions and for other imaging applications amenable to the smaller format of this prototype imaging system. The detector head had 32 cadmium telluride semiconductor arrays with a total of 1,024 pixels, and with application-specific integrated circuits (ASICs) and a tungsten collimator. The entire assembly was encased in a lead housing measuring 152 mmx166 mmx65 mm. The effective visual field was 44.8 mmx44.8 mm. The energy resolution and imaging aspects were tested. Two spherical 5-mm- and 15-mm-diameter technetium-99m radioactive sources that had activities of 0.15 MBq and 100 MBq, respectively, were used to simulate a sentinel lymph node and an injection site. The relative detectability of these foci by the new detector and a conventional scintillation camera was studied. The prototype was also examined in a variety of clinical applications. Energy resolution [full-width at half-maximum (FWHM)] for a single element at the centre of the field of view was 4.2% at 140 keV (99mTc), and the mean energy resolution of the CdTe detector arrays was approximately 7.8%. The spatial resolution, represented by FWHM, had a mean value of 1.56 +/- 0.05 mm. Simulated node foci could be visualised clearly by the SSGC using a 15-s acquisition time. In preliminary clinical tests, the SSGC successfully imaged diseases in a variety of tissues, including salivary and thyroid glands, temporomandibular joints and sentinel lymph nodes. The SSGC has significant potential for diagnosing diseases and facilitating

Development of a Compton camera for prompt-gamma medical imaging

NASA Astrophysics Data System (ADS)

Aldawood, S.; Thirolf, P. G.; Miani, A.; Böhmer, M.; Dedes, G.; Gernhäuser, R.; Lang, C.; Liprandi, S.; Maier, L.; Marinšek, T.; Mayerhofer, M.; Schaart, D. R.; Lozano, I. Valencia; Parodi, K.

2017-11-01

A Compton camera-based detector system for photon detection from nuclear reactions induced by proton (or heavier ion) beams is under development at LMU Munich, targeting the online range verification of the particle beam in hadron therapy via prompt-gamma imaging. The detector is designed to be capable to reconstruct the photon source origin not only from the Compton scattering kinematics of the primary photon, but also to allow for tracking of the secondary Compton-scattered electrons, thus enabling a γ-source reconstruction also from incompletely absorbed photon events. The Compton camera consists of a monolithic LaBr3:Ce scintillation crystal, read out by a multi-anode PMT acting as absorber, preceded by a stacked array of 6 double-sided silicon strip detectors as scatterers. The detector components have been characterized both under offline and online conditions. The LaBr3:Ce crystal exhibits an excellent time and energy resolution. Using intense collimated 137Cs and 60Co sources, the monolithic scintillator was scanned on a fine 2D grid to generate a reference library of light amplitude distributions that allows for reconstructing the photon interaction position using a k-Nearest Neighbour (k-NN) algorithm. Systematic studies were performed to investigate the performance of the reconstruction algorithm, revealing an improvement of the spatial resolution with increasing photon energy to an optimum value of 3.7(1)mm at 1.33 MeV, achieved with the Categorical Average Pattern (CAP) modification of the k-NN algorithm.

Application of gamma imaging techniques for the characterisation of position sensitive gamma detectors

NASA Astrophysics Data System (ADS)

Habermann, T.; Didierjean, F.; Duchêne, G.; Filliger, M.; Gerl, J.; Kojouharov, I.; Li, G.; Pietralla, N.; Schaffner, H.; Sigward, M.-H.

2017-11-01

A device to characterize position-sensitive germanium detectors has been implemented at GSI. The main component of this so called scanning table is a gamma camera that is capable of producing online 2D images of the scanned detector by means of a PET technique. To calibrate the gamma camera Compton imaging is employed. The 2D data can be processed further offline to obtain depth information. Of main interest is the response of the scanned detector in terms of the digitized pulse shapes from the preamplifier. This is an important input for pulse-shape analysis algorithms as they are in use for gamma tracking arrays in gamma spectroscopy. To validate the scanning table, a comparison of its results with a second scanning table implemented at the IPHC Strasbourg is envisaged. For this purpose a pixelated germanium detector has been scanned.

Development of a high sensitivity pinhole type gamma camera using semiconductors for low dose rate fields

NASA Astrophysics Data System (ADS)

Ueno, Yuichiro; Takahashi, Isao; Ishitsu, Takafumi; Tadokoro, Takahiro; Okada, Koichi; Nagumo, Yasushi; Fujishima, Yasutake; Yoshida, Akira; Umegaki, Kikuo

2018-06-01

We developed a pinhole type gamma camera, using a compact detector module of a pixelated CdTe semiconductor, which has suitable sensitivity and quantitative accuracy for low dose rate fields. In order to improve the sensitivity of the pinhole type semiconductor gamma camera, we adopted three methods: a signal processing method to set the discriminating level lower, a high sensitivity pinhole collimator and a smoothing image filter that improves the efficiency of the source identification. We tested basic performances of the developed gamma camera and carefully examined effects of the three methods. From the sensitivity test, we found that the effective sensitivity was about 21 times higher than that of the gamma camera for high dose rate fields which we had previously developed. We confirmed that the gamma camera had sufficient sensitivity and high quantitative accuracy; for example, a weak hot spot (0.9 μSv/h) around a tree root could be detected within 45 min in a low dose rate field test, and errors of measured dose rates with point sources were less than 7% in a dose rate accuracy test.

The spatial resolution of a rotating gamma camera tomographic facility.

PubMed

Webb, S; Flower, M A; Ott, R J; Leach, M O; Inamdar, R

1983-12-01

An important feature determining the spatial resolution in transverse sections reconstructed by convolution and back-projection is the frequency filter corresponding to the convolution kernel. Equations have been derived giving the theoretical spatial resolution, for a perfect detector and noise-free data, using four filter functions. Experiments have shown that physical constraints will always limit the resolution that can be achieved with a given system. The experiments indicate that the region of the frequency spectrum between KN/2 and KN where KN is the Nyquist frequency does not contribute significantly to resolution. In order to investigate the physical effect of these filter functions, the spatial resolution of reconstructed images obtained with a GE 400T rotating gamma camera has been measured. The results obtained serve as an aid to choosing appropriate reconstruction filters for use with a rotating gamma camera system.

TU-H-206-01: An Automated Approach for Identifying Geometric Distortions in Gamma Cameras

DOE Office of Scientific and Technical Information (OSTI.GOV)

Mann, S; Nelson, J; Samei, E

2016-06-15

Purpose: To develop a clinically-deployable, automated process for detecting artifacts in routine nuclear medicine (NM) quality assurance (QA) bar phantom images. Methods: An artifact detection algorithm was created to analyze bar phantom images as part of an ongoing QA program. A low noise, high resolution reference image was acquired from an x-ray of the bar phantom with a Philips Digital Diagnost system utilizing image stitching. NM bar images, acquired for 5 million counts over a 512×512 matrix, were registered to the template image by maximizing mutual information (MI). The MI index was used as an initial test for artifacts; lowmore » values indicate an overall presence of distortions regardless of their spatial location. Images with low MI scores were further analyzed for bar linearity, periodicity, alignment, and compression to locate differences with respect to the template. Findings from each test were spatially correlated and locations failing multiple tests were flagged as potential artifacts requiring additional visual analysis. The algorithm was initially deployed for GE Discovery 670 and Infinia Hawkeye gamma cameras. Results: The algorithm successfully identified clinically relevant artifacts from both systems previously unnoticed by technologists performing the QA. Average MI indices for artifact-free images are 0.55. Images with MI indices < 0.50 have shown 100% sensitivity and specificity for artifact detection when compared with a thorough visual analysis. Correlation of geometric tests confirms the ability to spatially locate the most likely image regions containing an artifact regardless of initial phantom orientation. Conclusion: The algorithm shows the potential to detect gamma camera artifacts that may be missed by routine technologist inspections. Detection and subsequent correction of artifacts ensures maximum image quality and may help to identify failing hardware before it impacts clinical workflow. Going forward, the algorithm is

Imaging system for cardiac planar imaging using a dedicated dual-head gamma camera

DOEpatents

Majewski, Stanislaw [Morgantown, VA; Umeno, Marc M [Woodinville, WA

2011-09-13

A cardiac imaging system employing dual gamma imaging heads co-registered with one another to provide two dynamic simultaneous views of the heart sector of a patient torso. A first gamma imaging head is positioned in a first orientation with respect to the heart sector and a second gamma imaging head is positioned in a second orientation with respect to the heart sector. An adjustment arrangement is capable of adjusting the distance between the separate imaging heads and the angle between the heads. With the angle between the imaging heads set to 180 degrees and operating in a range of 140-159 keV and at a rate of up to 500kHz, the imaging heads are co-registered to produce simultaneous dynamic recording of two stereotactic views of the heart. The use of co-registered imaging heads maximizes the uniformity of detection sensitivity of blood flow in and around the heart over the whole heart volume and minimizes radiation absorption effects. A normalization/image fusion technique is implemented pixel-by-corresponding pixel to increase signal for any cardiac region viewed in two images obtained from the two opposed detector heads for the same time bin. The imaging system is capable of producing enhanced first pass studies, bloodpool studies including planar, gated and non-gated EKG studies, planar EKG perfusion studies, and planar hot spot imaging.

Performance of cardiac cadmium-zinc-telluride gamma camera imaging in coronary artery disease: a review from the cardiovascular committee of the European Association of Nuclear Medicine (EANM).

PubMed

Agostini, Denis; Marie, Pierre-Yves; Ben-Haim, Simona; Rouzet, François; Songy, Bernard; Giordano, Alessandro; Gimelli, Alessia; Hyafil, Fabien; Sciagrà, Roberto; Bucerius, Jan; Verberne, Hein J; Slart, Riemer H J A; Lindner, Oliver; Übleis, Christopher; Hacker, Marcus

2016-12-01

The trade-off between resolution and count sensitivity dominates the performance of standard gamma cameras and dictates the need for relatively high doses of radioactivity of the used radiopharmaceuticals in order to limit image acquisition duration. The introduction of cadmium-zinc-telluride (CZT)-based cameras may overcome some of the limitations against conventional gamma cameras. CZT cameras used for the evaluation of myocardial perfusion have been shown to have a higher count sensitivity compared to conventional single photon emission computed tomography (SPECT) techniques. CZT image quality is further improved by the development of a dedicated three-dimensional iterative reconstruction algorithm, based on maximum likelihood expectation maximization (MLEM), which corrects for the loss in spatial resolution due to line response function of the collimator. All these innovations significantly reduce imaging time and result in a lower patient's radiation exposure compared with standard SPECT. To guide current and possible future users of the CZT technique for myocardial perfusion imaging, the Cardiovascular Committee of the European Association of Nuclear Medicine, starting from the experience of its members, has decided to examine the current literature regarding procedures and clinical data on CZT cameras. The committee hereby aims 1) to identify the main acquisitions protocols; 2) to evaluate the diagnostic and prognostic value of CZT derived myocardial perfusion, and finally 3) to determine the impact of CZT on radiation exposure.

3D tomographic imaging with the γ-eye planar scintigraphic gamma camera

NASA Astrophysics Data System (ADS)

Tunnicliffe, H.; Georgiou, M.; Loudos, G. K.; Simcox, A.; Tsoumpas, C.

2017-11-01

γ-eye is a desktop planar scintigraphic gamma camera (100 mm × 50 mm field of view) designed by BET Solutions as an affordable tool for dynamic, whole body, small-animal imaging. This investigation tests the viability of using γ-eye for the collection of tomographic data for 3D SPECT reconstruction. Two software packages, QSPECT and STIR (software for tomographic image reconstruction), have been compared. Reconstructions have been performed using QSPECT’s implementation of the OSEM algorithm and STIR’s OSMAPOSL (Ordered Subset Maximum A Posteriori One Step Late) and OSSPS (Ordered Subsets Separable Paraboloidal Surrogate) algorithms. Reconstructed images of phantom and mouse data have been assessed in terms of spatial resolution, sensitivity to varying activity levels and uniformity. The effect of varying the number of iterations, the voxel size (1.25 mm default voxel size reduced to 0.625 mm and 0.3125 mm), the point spread function correction and the weight of prior terms were explored. While QSPECT demonstrated faster reconstructions, STIR outperformed it in terms of resolution (as low as 1 mm versus 3 mm), particularly when smaller voxel sizes were used, and in terms of uniformity, particularly when prior terms were used. Little difference in terms of sensitivity was seen throughout.

131I activity quantification of gamma camera planar images.

PubMed

Barquero, Raquel; Garcia, Hugo P; Incio, Monica G; Minguez, Pablo; Cardenas, Alexander; Martínez, Daniel; Lassmann, Michael

2017-02-07

A procedure to estimate the activity in target tissues in patients during the therapeutic administration of 131 I radiopharmaceutical treatment for thyroid conditions (hyperthyroidism and differentiated thyroid cancer) using a gamma camera (GC) with a high energy (HE) collimator, is proposed. Planar images are acquired for lesions of different sizes r, and at different distances d, in two HE GC systems. Defining a region of interest (ROI) on the image of size r, total counts n g are measured. Sensitivity S (cps MBq -1 ) in each acquisition is estimated as the product of the geometric G and the intrinsic efficiency η 0 . The mean fluence of 364 keV photons arriving at the ROI per disintegration G, is calculated with the MCNPX code, simulating the entire GC and the HE collimator. Intrinsic efficiency η 0 is estimated from a calibration measurement of a plane reference source of 131 I in air. Values of G and S for two GC systems-Philips Skylight and Siemens e-cam-are calculated. The total range of possible sensitivity values in thyroidal imaging in the e-cam and skylight GC measure from 7 cps MBq -1 to 35 cps MBq -1 , and from 6 cps MBq -1 to 29 cps MBq -1 , respectively. These sensitivity values have been verified with the SIMIND code, with good agreement between them. The results have been validated with experimental measurements in air, and in a medium with scatter and attenuation. The counts in the ROI can be produced by direct, scatter and penetration photons. The fluence value for direct photons is constant for any r and d values, but scatter and penetration photons show different values related to specific r and d values, resulting in the large sensitivity differences found. The sensitivity in thyroidal GC planar imaging is strongly dependent on uptake size, and distance from the GC. An individual value for the acquisition sensitivity of each lesion can significantly alleviate the level of uncertainty in the measurement of thyroid uptake activity for each

131I activity quantification of gamma camera planar images

NASA Astrophysics Data System (ADS)

Barquero, Raquel; Garcia, Hugo P.; Incio, Monica G.; Minguez, Pablo; Cardenas, Alexander; Martínez, Daniel; Lassmann, Michael

2017-02-01

A procedure to estimate the activity in target tissues in patients during the therapeutic administration of 131I radiopharmaceutical treatment for thyroid conditions (hyperthyroidism and differentiated thyroid cancer) using a gamma camera (GC) with a high energy (HE) collimator, is proposed. Planar images are acquired for lesions of different sizes r, and at different distances d, in two HE GC systems. Defining a region of interest (ROI) on the image of size r, total counts n g are measured. Sensitivity S (cps MBq-1) in each acquisition is estimated as the product of the geometric G and the intrinsic efficiency η 0. The mean fluence of 364 keV photons arriving at the ROI per disintegration G, is calculated with the MCNPX code, simulating the entire GC and the HE collimator. Intrinsic efficiency η 0 is estimated from a calibration measurement of a plane reference source of 131I in air. Values of G and S for two GC systems—Philips Skylight and Siemens e-cam—are calculated. The total range of possible sensitivity values in thyroidal imaging in the e-cam and skylight GC measure from 7 cps MBq-1 to 35 cps MBq-1, and from 6 cps MBq-1 to 29 cps MBq-1, respectively. These sensitivity values have been verified with the SIMIND code, with good agreement between them. The results have been validated with experimental measurements in air, and in a medium with scatter and attenuation. The counts in the ROI can be produced by direct, scatter and penetration photons. The fluence value for direct photons is constant for any r and d values, but scatter and penetration photons show different values related to specific r and d values, resulting in the large sensitivity differences found. The sensitivity in thyroidal GC planar imaging is strongly dependent on uptake size, and distance from the GC. An individual value for the acquisition sensitivity of each lesion can significantly alleviate the level of uncertainty in the measurement of thyroid uptake activity for each patient.

Sentinel node detection in early breast cancer with intraoperative portable gamma camera: UK experience.

PubMed

Ghosh, Debashis; Michalopoulos, Nikolaos V; Davidson, Timothy; Wickham, Fred; Williams, Norman R; Keshtgar, Mohammed R

2017-04-01

Access to nuclear medicine department for sentinel node imaging remains an issue in number of hospitals in the UK and many parts of the world. Sentinella ® is a portable imaging camera used intra-operatively to produce real time visual localisation of sentinel lymph nodes. Sentinella ® was tested in a controlled laboratory environment at our centre and we report our experience on the first use of this technology from UK. Moreover, preoperative scintigrams of the axilla were obtained in 144 patients undergoing sentinel node biopsy using conventional gamma camera. Sentinella ® scans were done intra-operatively to correlate with the pre-operative scintigram and to determine presence of any residual hot node after the axilla was deemed to be clear based on the silence of the hand held gamma probe. Sentinella ® detected significantly more nodes compared with CGC (p < 0.0001). Sentinella ® picked up extra nodes in 5/144 cases after the axilla was found silent using hand held gamma probe. In 2/144 cases, extra nodes detected by Sentinella ® confirmed presence of tumour cells that led to a complete axillary clearance. Sentinella ® is a reliable technique for intra-operative localisation of radioactive nodes. It provides increased nodal visualisation rates compared to static scintigram imaging and proves to be an important tool for harvesting all hot sentinel nodes. This portable gamma camera can definitely replace the use of conventional lymphoscintigrams saving time and money both for patients and the health system. Copyright © 2016 Elsevier Ltd. All rights reserved.

Establishment of Imaging Spectroscopy of Nuclear Gamma-Rays based on Geometrical Optics.

PubMed

Tanimori, Toru; Mizumura, Yoshitaka; Takada, Atsushi; Miyamoto, Shohei; Takemura, Taito; Kishimoto, Tetsuro; Komura, Shotaro; Kubo, Hidetoshi; Kurosawa, Shunsuke; Matsuoka, Yoshihiro; Miuchi, Kentaro; Mizumoto, Tetsuya; Nakamasu, Yuma; Nakamura, Kiseki; Parker, Joseph D; Sawano, Tatsuya; Sonoda, Shinya; Tomono, Dai; Yoshikawa, Kei

2017-02-03

Since the discovery of nuclear gamma-rays, its imaging has been limited to pseudo imaging, such as Compton Camera (CC) and coded mask. Pseudo imaging does not keep physical information (intensity, or brightness in Optics) along a ray, and thus is capable of no more than qualitative imaging of bright objects. To attain quantitative imaging, cameras that realize geometrical optics is essential, which would be, for nuclear MeV gammas, only possible via complete reconstruction of the Compton process. Recently we have revealed that "Electron Tracking Compton Camera" (ETCC) provides a well-defined Point Spread Function (PSF). The information of an incoming gamma is kept along a ray with the PSF and that is equivalent to geometrical optics. Here we present an imaging-spectroscopic measurement with the ETCC. Our results highlight the intrinsic difficulty with CCs in performing accurate imaging, and show that the ETCC surmounts this problem. The imaging capability also helps the ETCC suppress the noise level dramatically by ~3 orders of magnitude without a shielding structure. Furthermore, full reconstruction of Compton process with the ETCC provides spectra free of Compton edges. These results mark the first proper imaging of nuclear gammas based on the genuine geometrical optics.

Estimation of bone mineral content using gamma camera: A real possibility

DOE Office of Scientific and Technical Information (OSTI.GOV)

Levy, L.M.; Hoory, S.; Bandyopadhyay, D.

1985-05-01

Osteopenia and Osteoporosis are the diseases related to loss of bone minerals. At present, dual photon absorptiometry using a dedicated specially built scanner along with a very high source of Gd-153 is being used as a diagnostic tool for the early detection of bone loss. The present study was undertaken to explore the possibility that gamma cameras which are widely available in all Nuclear Medicine departments could be used successfully to evaluate bone mineral content. A Siemens LFOV gamma camera equipped with a converging collimator was used for this purpose. A fixed source (100 mCi) of Gd-153 was placed atmore » the focal point of the collimator. A series of calcium chloride solutions of varying concentrations in plastic vials were placed near the center of the collimator and imaged both in air and water. Both 44 Kev and 100 Kev images were digitized in 128 x 128 matrices and processed in a CD and A Delta system attached to a VAX 11-750 computer. Uniformity corrections for each field of view were applied and the attenuation coefficients of calcium chloride for both peaks of Gd-153 were evaluated. In addition, due to the high count rate, corrections for the dead time losses were also found to be essential. An excellent concordance between the estimated Calcium contents and that actually present were obtained by this technic. In conclusion, use of gamma camera for the routine evaluation of Osteoporosis appears to be highly promising and worth pursuing.« less

Development and characterization of a round hand-held silicon photomultiplier based gamma camera for intraoperative imaging

PubMed Central

Popovic, Kosta; McKisson, Jack E.; Kross, Brian; Lee, Seungjoon; McKisson, John; Weisenberger, Andrew G.; Proffitt, James; Stolin, Alexander; Majewski, Stan; Williams, Mark B.

2017-01-01

This paper describes the development of a hand-held gamma camera for intraoperative surgical guidance that is based on silicon photomultiplier (SiPM) technology. The camera incorporates a cerium doped lanthanum bromide (LaBr3:Ce) plate scintillator, an array of 80 SiPM photodetectors and a two-layer parallel-hole collimator. The field of view is circular with a 60 mm diameter. The disk-shaped camera housing is 75 mm in diameter, approximately 40.5 mm thick and has a mass of only 1.4 kg, permitting either hand-held or arm-mounted use. All camera components are integrated on a mobile cart that allows easy transport. The camera was developed for use in surgical procedures including determination of the location and extent of primary carcinomas, detection of secondary lesions and sentinel lymph node biopsy (SLNB). Here we describe the camera design and its principal operating characteristics, including spatial resolution, energy resolution, sensitivity uniformity, and geometric linearity. The gamma camera has an intrinsic spatial resolution of 4.2 mm FWHM, an energy resolution of 21.1 % FWHM at 140 keV, and a sensitivity of 481 and 73 cps/MBq when using the single- and double-layer collimators, respectively. PMID:28286345

Gamma-Ray Imaging for Explosives Detection

NASA Technical Reports Server (NTRS)

deNolfo, G. A.; Hunter, S. D.; Barbier, L. M.; Link, J. T.; Son, S.; Floyd, S. R.; Guardala, N.; Skopec, M.; Stark, B.

2008-01-01

We describe a gamma-ray imaging camera (GIC) for active interrogation of explosives being developed by NASA/GSFC and NSWCICarderock. The GIC is based on the Three-dimensional Track Imager (3-DTI) technology developed at GSFC for gamma-ray astrophysics. The 3-DTI, a large volume time-projection chamber, provides accurate, approx.0.4 mm resolution, 3-D tracking of charged particles. The incident direction of gamma rays, E, > 6 MeV, are reconstructed from the momenta and energies of the electron-positron pair resulting from interactions in the 3-DTI volume. The optimization of the 3-DTI technology for this specific application and the performance of the GIC from laboratory tests is presented.

A didactic experiment showing the Compton scattering by means of a clinical gamma camera.

PubMed

Amato, Ernesto; Auditore, Lucrezia; Campennì, Alfredo; Minutoli, Fabio; Cucinotta, Mariapaola; Sindoni, Alessandro; Baldari, Sergio

2017-06-01

We describe a didactic approach aimed to explain the effect of Compton scattering in nuclear medicine imaging, exploiting the comparison of a didactic experiment with a gamma camera with the outcomes from a Monte Carlo simulation of the same experimental apparatus. We employed a 99m Tc source emitting 140.5keV photons, collimated in the upper direction through two pinholes, shielded by 6mm of lead. An aluminium cylinder was placed on the source at 50mm of distance. The energy of the scattered photons was measured on the spectra acquired by the gamma camera. We observed that the gamma ray energy measured at each step of rotation gradually decreased from the characteristic energy of 140.5keV at 0° to 102.5keV at 120°. A comparison between the obtained data and the expected results from the Compton formula and from the Monte Carlo simulation revealed a full agreement within the experimental error (relative errors between -0.56% and 1.19%), given by the energy resolution of the gamma camera. Also the electron rest mass has been evaluated satisfactorily. The experiment was found useful in explaining nuclear medicine residents the phenomenology of the Compton scattering and its importance in the nuclear medicine imaging, and it can be profitably proposed during the training of medical physics residents as well. Copyright © 2017 Associazione Italiana di Fisica Medica. Published by Elsevier Ltd. All rights reserved.

Optimization and verification of image reconstruction for a Compton camera towards application as an on-line monitor for particle therapy

NASA Astrophysics Data System (ADS)

Taya, T.; Kataoka, J.; Kishimoto, A.; Tagawa, L.; Mochizuki, S.; Toshito, T.; Kimura, M.; Nagao, Y.; Kurita, K.; Yamaguchi, M.; Kawachi, N.

2017-07-01

Particle therapy is an advanced cancer therapy that uses a feature known as the Bragg peak, in which particle beams suddenly lose their energy near the end of their range. The Bragg peak enables particle beams to damage tumors effectively. To achieve precise therapy, the demand for accurate and quantitative imaging of the beam irradiation region or dosage during therapy has increased. The most common method of particle range verification is imaging of annihilation gamma rays by positron emission tomography. Not only 511-keV gamma rays but also prompt gamma rays are generated during therapy; therefore, the Compton camera is expected to be used as an on-line monitor for particle therapy, as it can image these gamma rays in real time. Proton therapy, one of the most common particle therapies, uses a proton beam of approximately 200 MeV, which has a range of ~ 25 cm in water. As gamma rays are emitted along the path of the proton beam, quantitative evaluation of the reconstructed images of diffuse sources becomes crucial, but it is far from being fully developed for Compton camera imaging at present. In this study, we first quantitatively evaluated reconstructed Compton camera images of uniformly distributed diffuse sources, and then confirmed that our Compton camera obtained 3 %(1 σ) and 5 %(1 σ) uniformity for line and plane sources, respectively. Based on this quantitative study, we demonstrated on-line gamma imaging during proton irradiation. Through these studies, we show that the Compton camera is suitable for future use as an on-line monitor for particle therapy.

Development of an LYSO based gamma camera for positron and scinti-mammography

NASA Astrophysics Data System (ADS)

Liang, H.-C.; Jan, M.-L.; Lin, W.-C.; Yu, S.-F.; Su, J.-L.; Shen, L.-H.

2009-08-01

In this research, characteristics of combination of PSPMTs (position sensitive photo-multiplier tube) to form a larger detection area is studied. A home-made linear divider circuit was built for merging signals and readout. Borosilicate glasses were chosen for the scintillation light sharing in the crossover region. Deterioration effect caused by the light guide was understood. The influences of light guide and crossover region on the separable crystal size were evaluated. According to the test results, a gamma camera with a crystal block of 90 × 90 mm2 covered area, composed of 2 mm LYSO crystal pixels, was designed and fabricated. Measured performances showed that this camera worked fine in both 511 keV and lower energy gammas. The light loss behaviour within the crossover region was analyzed and realized. Through count rate measurements, the 176Lu nature background didn't show severe influence on the single photon imaging and exhibited an amount of less than 1/3 of all the events acquired. These results show that with using light sharing techniques, combination of multiple PSPMTs in both X and Y directions to build a large area imaging detector is capable to be achieved. Also this camera design is feasible to keep both the abilities for positron and single photon breast imaging applications. Separable crystal size is 2 mm with 2 mm thick glass applied for the light sharing in current status.

A SPECT Scanner for Rodent Imaging Based on Small-Area Gamma Cameras

NASA Astrophysics Data System (ADS)

Lage, Eduardo; Villena, José L.; Tapias, Gustavo; Martinez, Naira P.; Soto-Montenegro, Maria L.; Abella, Mónica; Sisniega, Alejandro; Pino, Francisco; Ros, Domènec; Pavia, Javier; Desco, Manuel; Vaquero, Juan J.

2010-10-01

We developed a cost-effective SPECT scanner prototype (rSPECT) for in vivo imaging of rodents based on small-area gamma cameras. Each detector consists of a position-sensitive photomultiplier tube (PS-PMT) coupled to a 30 x 30 Nal(Tl) scintillator array and electronics attached to the PS-PMT sockets for adapting the detector signals to an in-house developed data acquisition system. The detector components are enclosed in a lead-shielded case with a receptacle to insert the collimators. System performance was assessed using 99mTc for a high-resolution parallel-hole collimator, and for a 0.75-mm pinhole collimator with a 60° aperture angle and a 42-mm collimator length. The energy resolution is about 10.7% of the photopeak energy. The overall system sensitivity is about 3 cps/μCi/detector and planar spatial resolution ranges from 2.4 mm at 1 cm source-to-collimator distance to 4.1 mm at 4.5 cm with parallel-hole collimators. With pinhole collimators planar spatial resolution ranges from 1.2 mm at 1 cm source-to-collimator distance to 2.4 mm at 4.5 cm; sensitivity at these distances ranges from 2.8 to 0.5 cps/μCi/detector. Tomographic hot-rod phantom images are presented together with images of bone, myocardium and brain of living rodents to demonstrate the feasibility of preclinical small-animal studies with the rSPECT.

Characterization of a small CsI(Na)-WSF-SiPM gamma camera prototype using 99mTc

NASA Astrophysics Data System (ADS)

Castro, I. F.; Soares, A. J.; Moutinho, L. M.; Ferreira, M. A.; Ferreira, R.; Combo, A.; Muchacho, F.; Veloso, J. F. C. A.

2013-03-01

A small field of view gamma camera is being developed, aiming for applications in scintimammography, sentinel lymph node detection or small animal imaging and research. The proposed wavelength-shifting fibre (WSF) gamma camera consists of two perpendicular sets of WSFs covering both sides of a CsI(Na) crystal, such that the fibres positioned at the bottom of the crystal provide the x coordinate and the ones on top the y coordinate of the gamma photon interaction point. The 2D position is given by highly sensitive photodetectors reading out each WSF and the energy information is provided by PMTs that cover the full detector area. This concept has the advantage of using N+N instead of N × N photodetectors to cover an identical imaging area, and is being applied using for the first time SiPMs. Previous studies carried out with 57Co have proved the feasibility of this concept using SiPM readout. In this work, we present experimental results from true 2D image acquisitions with a 10+10 SiPMs prototype, i.e. 10 × 10 mm2, using a parallel-hole collimator and different samples filled with 99mTc solution. The performance of the small prototype in these conditions is evaluated through the characterization of different gamma camera parameters, such as energy and spatial resolution. Ongoing advances towards a larger prototype of 100+100 SiPMs (10 × 10 cm2) are also presented.

Color reproduction software for a digital still camera

NASA Astrophysics Data System (ADS)

Lee, Bong S.; Park, Du-Sik; Nam, Byung D.

1998-04-01

We have developed a color reproduction software for a digital still camera. The image taken by the camera was colorimetrically reproduced on the monitor after characterizing the camera and the monitor, and color matching between two devices. The reproduction was performed at three levels; level processing, gamma correction, and color transformation. The image contrast was increased after the level processing adjusting the level of dark and bright portions of the image. The relationship between the level processed digital values and the measured luminance values of test gray samples was calculated, and the gamma of the camera was obtained. The method for getting the unknown monitor gamma was proposed. As a result, the level processed values were adjusted by the look-up table created by the camera and the monitor gamma correction. For a color transformation matrix for the camera, 3 by 3 or 3 by 4 matrix was used, which was calculated by the regression between the gamma corrected values and the measured tristimulus values of each test color samples the various reproduced images were displayed on the dialogue box implemented in our software, which were generated according to four illuminations for the camera and three color temperatures for the monitor. An user can easily choose he best reproduced image comparing each others.

ProxiScan™: A Novel Camera for Imaging Prostate Cancer

ScienceCinema

Ralph James

2017-12-09

ProxiScan is a compact gamma camera suited for high-resolution imaging of prostate cancer. Developed by Brookhaven National Laboratory and Hybridyne Imaging Technologies, Inc., ProxiScan won a 2009 R&D 100 Award, sponsored by R&D Magazine to recognize t

Europe's space camera unmasks a cosmic gamma-ray machine

NASA Astrophysics Data System (ADS)

1996-11-01

The new-found neutron star is the visible counterpart of a pulsating radio source, Pulsar 1055-52. It is a mere 20 kilometres wide. Although the neutron star is very hot, at about a million degrees C, very little of its radiant energy takes the form of visible light. It emits mainly gamma-rays, an extremely energetic form of radiation. By examining it at visible wavelengths, astronomers hope to figure out why Pulsar 1055-52 is the most efficient generator of gamma-rays known so far, anywhere the Universe. The Faint Object Camera found Pulsar 1055-52 in near ultraviolet light at 3400 angstroms, a little shorter in wavelength than the violet light at the extremity of the human visual range. Roberto Mignani, Patrizia Caraveo and Giovanni Bignami of the Istituto di Fisica Cosmica in Milan, Italy, report its optical identification in a forthcoming issue of Astrophysical Journal Letters (1 January 1997). The formal name of the object is PSR 1055-52. Evading the glare of an adjacent star The Italian team had tried since 1988 to spot Pulsar 1055-52 with two of the most powerful ground-based optical telescopes in the Southern Hemisphere. These were the 3.6-metre Telescope and the 3.5-metre New Technology Telescope of the European Southern Observatory at La Silla, Chile. Unfortunately an ordinary star 100,000 times brighter lay in almost the same direction in the sky, separated from the neutron star by only a thousandth of a degree. The Earth's atmosphere defocused the star's light sufficiently to mask the glimmer from Pulsar 1055-52. The astronomers therefore needed an instrument in space. The Faint Object Camera offered the best precision and sensitivity to continue the hunt. Devised by European astronomers to complement the American wide field camera in the Hubble Space Telescope, the Faint Object Camera has a relatively narrow field of view. It intensifies the image of a faint object by repeatedly accelerating electrons from photo-electric films, so as to produce

Gamma ray imager on the DIII-D tokamak

DOE Office of Scientific and Technical Information (OSTI.GOV)

Pace, D. C., E-mail: pacedc@fusion.gat.com; Taussig, D.; Eidietis, N. W.

2016-04-15

A gamma ray camera is built for the DIII-D tokamak [J. Luxon, Nucl. Fusion 42, 614 (2002)] that provides spatial localization and energy resolution of gamma flux by combining a lead pinhole camera with custom-built detectors and optimized viewing geometry. This diagnostic system is installed on the outer midplane of the tokamak such that its 123 collimated sightlines extend across the tokamak radius while also covering most of the vertical extent of the plasma volume. A set of 30 bismuth germanate detectors can be secured in any of the available sightlines, allowing for customizable coverage in experiments with runaway electronsmore » in the energy range of 1–60 MeV. Commissioning of the gamma ray imager includes the quantification of electromagnetic noise sources in the tokamak machine hall and a measurement of the energy spectrum of background gamma radiation. First measurements of gamma rays coming from the plasma provide a suitable testbed for implementing pulse height analysis that provides the energy of detected gamma photons.« less

Gamma ray imager on the DIII-D tokamak

DOE PAGES

Pace, D. C.; Cooper, C. M.; Taussig, D.; ...

2016-04-13

A gamma ray camera is built for the DIII-D tokamak [J. Luxon, Nucl. Fusion 42, 614 (2002)] that provides spatial localization and energy resolution of gamma flux by combining a lead pinhole camera with custom-built detectors and optimized viewing geometry. This diagnostic system is installed on the outer midplane of the tokamak such that its 123 collimated sightlines extend across the tokamak radius while also covering most of the vertical extent of the plasma volume. A set of 30 bismuth germanate detectors can be secured in any of the available sightlines, allowing for customizable coverage in experiments with runaway electronsmore » in the energy range of 1- 60 MeV. Commissioning of the gamma ray imager includes the quantification of electromagnetic noise sources in the tokamak machine hall and a measurement of the energy spectrum of background gamma radiation. In conclusion, first measurements of gamma rays coming from the plasma provide a suitable testbed for implementing pulse height analysis that provides the energy of detected gamma photons.« less

A panoramic coded aperture gamma camera for radioactive hotspots localization

NASA Astrophysics Data System (ADS)

Paradiso, V.; Amgarou, K.; Blanc De Lanaute, N.; Schoepff, V.; Amoyal, G.; Mahe, C.; Beltramello, O.; Liénard, E.

2017-11-01

A known disadvantage of the coded aperture imaging approach is its limited field-of-view (FOV), which often results insufficient when analysing complex dismantling scenes such as post-accidental scenarios, where multiple measurements are needed to fully characterize the scene. In order to overcome this limitation, a panoramic coded aperture γ-camera prototype has been developed. The system is based on a 1 mm thick CdTe detector directly bump-bonded to a Timepix readout chip, developed by the Medipix2 collaboration (256 × 256 pixels, 55 μm pitch, 14.08 × 14.08 mm2 sensitive area). A MURA pattern coded aperture is used, allowing for background subtraction without the use of heavy shielding. Such system is then combined with a USB color camera. The output of each measurement is a semi-spherical image covering a FOV of 360 degrees horizontally and 80 degrees vertically, rendered in spherical coordinates (θ,phi). The geometrical shapes of the radiation-emitting objects are preserved by first registering and stitching the optical images captured by the prototype, and applying, subsequently, the same transformations to their corresponding radiation images. Panoramic gamma images generated by using the technique proposed in this paper are described and discussed, along with the main experimental results obtained in laboratories campaigns.

Establishment of Imaging Spectroscopy of Nuclear Gamma-Rays based on Geometrical Optics

PubMed Central

Tanimori, Toru; Mizumura, Yoshitaka; Takada, Atsushi; Miyamoto, Shohei; Takemura, Taito; Kishimoto, Tetsuro; Komura, Shotaro; Kubo, Hidetoshi; Kurosawa, Shunsuke; Matsuoka, Yoshihiro; Miuchi, Kentaro; Mizumoto, Tetsuya; Nakamasu, Yuma; Nakamura, Kiseki; Parker, Joseph D.; Sawano, Tatsuya; Sonoda, Shinya; Tomono, Dai; Yoshikawa, Kei

2017-01-01

Since the discovery of nuclear gamma-rays, its imaging has been limited to pseudo imaging, such as Compton Camera (CC) and coded mask. Pseudo imaging does not keep physical information (intensity, or brightness in Optics) along a ray, and thus is capable of no more than qualitative imaging of bright objects. To attain quantitative imaging, cameras that realize geometrical optics is essential, which would be, for nuclear MeV gammas, only possible via complete reconstruction of the Compton process. Recently we have revealed that “Electron Tracking Compton Camera” (ETCC) provides a well-defined Point Spread Function (PSF). The information of an incoming gamma is kept along a ray with the PSF and that is equivalent to geometrical optics. Here we present an imaging-spectroscopic measurement with the ETCC. Our results highlight the intrinsic difficulty with CCs in performing accurate imaging, and show that the ETCC surmounts this problem. The imaging capability also helps the ETCC suppress the noise level dramatically by ~3 orders of magnitude without a shielding structure. Furthermore, full reconstruction of Compton process with the ETCC provides spectra free of Compton edges. These results mark the first proper imaging of nuclear gammas based on the genuine geometrical optics. PMID:28155870

Flexible mini gamma camera reconstructions of extended sources using step and shoot and list mode.

PubMed

Gardiazabal, José; Matthies, Philipp; Vogel, Jakob; Frisch, Benjamin; Navab, Nassir; Ziegler, Sibylle; Lasser, Tobias

2016-12-01

Hand- and robot-guided mini gamma cameras have been introduced for the acquisition of single-photon emission computed tomography (SPECT) images. Less cumbersome than whole-body scanners, they allow for a fast acquisition of the radioactivity distribution, for example, to differentiate cancerous from hormonally hyperactive lesions inside the thyroid. This work compares acquisition protocols and reconstruction algorithms in an attempt to identify the most suitable approach for fast acquisition and efficient image reconstruction, suitable for localization of extended sources, such as lesions inside the thyroid. Our setup consists of a mini gamma camera with precise tracking information provided by a robotic arm, which also provides reproducible positioning for our experiments. Based on a realistic phantom of the thyroid including hot and cold nodules as well as background radioactivity, the authors compare "step and shoot" (SAS) and continuous data (CD) acquisition protocols in combination with two different statistical reconstruction methods: maximum-likelihood expectation-maximization (ML-EM) for time-integrated count values and list-mode expectation-maximization (LM-EM) for individually detected gamma rays. In addition, the authors simulate lower uptake values by statistically subsampling the experimental data in order to study the behavior of their approach without changing other aspects of the acquired data. All compared methods yield suitable results, resolving the hot nodules and the cold nodule from the background. However, the CD acquisition is twice as fast as the SAS acquisition, while yielding better coverage of the thyroid phantom, resulting in qualitatively more accurate reconstructions of the isthmus between the lobes. For CD acquisitions, the LM-EM reconstruction method is preferable, as it yields comparable image quality to ML-EM at significantly higher speeds, on average by an order of magnitude. This work identifies CD acquisition protocols combined

A gamma beam profile imager for ELI-NP Gamma Beam System

NASA Astrophysics Data System (ADS)

Cardarelli, P.; Paternò, G.; Di Domenico, G.; Consoli, E.; Marziani, M.; Andreotti, M.; Evangelisti, F.; Squerzanti, S.; Gambaccini, M.; Albergo, S.; Cappello, G.; Tricomi, A.; Veltri, M.; Adriani, O.; Borgheresi, R.; Graziani, G.; Passaleva, G.; Serban, A.; Starodubtsev, O.; Variola, A.; Palumbo, L.

2018-06-01

The Gamma Beam System of ELI-Nuclear Physics is a high brilliance monochromatic gamma source based on the inverse Compton interaction between an intense high power laser and a bright electron beam with tunable energy. The source, currently being assembled in Magurele (Romania), is designed to provide a beam with tunable average energy ranging from 0.2 to 19.5 MeV, rms energy bandwidth down to 0.5% and flux of about 108 photons/s. The system includes a set of detectors for the diagnostic and complete characterization of the gamma beam. To evaluate the spatial distribution of the beam a gamma beam profile imager is required. For this purpose, a detector based on a scintillator target coupled to a CCD camera was designed and a prototype was tested at INFN-Ferrara laboratories. A set of analytical calculations and Monte Carlo simulations were carried out to optimize the imager design and evaluate the performance expected with ELI-NP gamma beam. In this work the design of the imager is described in detail, as well as the simulation tools used and the results obtained. The simulation parameters were tuned and cross-checked with the experimental measurements carried out on the assembled prototype using the beam from an x-ray tube.

Gamma-ray imaging system for real-time measurements in nuclear waste characterisation

NASA Astrophysics Data System (ADS)

Caballero, L.; Albiol Colomer, F.; Corbi Bellot, A.; Domingo-Pardo, C.; Leganés Nieto, J. L.; Agramunt Ros, J.; Contreras, P.; Monserrate, M.; Olleros Rodríguez, P.; Pérez Magán, D. L.

2018-03-01

A compact, portable and large field-of-view gamma camera that is able to identify, locate and quantify gamma-ray emitting radioisotopes in real-time has been developed. The device delivers spectroscopic and imaging capabilities that enable its use it in a variety of nuclear waste characterisation scenarios, such as radioactivity monitoring in nuclear power plants and more specifically for the decommissioning of nuclear facilities. The technical development of this apparatus and some examples of its application in field measurements are reported in this article. The performance of the presented gamma-camera is also benchmarked against other conventional techniques.

Photodetectors for the Advanced Gamma-ray Imaging System (AGIS)

NASA Astrophysics Data System (ADS)

Wagner, Robert G.; Advanced Gamma-ray Imaging System AGIS Collaboration

2010-03-01

The Advanced Gamma-Ray Imaging System (AGIS) is a concept for the next generation very high energy gamma-ray observatory. Design goals include an order of magnitude better sensitivity, better angular resolution, and a lower energy threshold than existing Cherenkov telescopes. Each telescope is equipped with a camera that detects and records the Cherenkov-light flashes from air showers. The camera is comprised of a pixelated focal plane of blue sensitive and fast (nanosecond) photon detectors that detect the photon signal and convert it into an electrical one. Given the scale of AGIS, the camera must be reliable and cost effective. The Schwarzschild-Couder optical design yields a smaller plate scale than present-day Cherenkov telescopes, enabling the use of more compact, multi-pixel devices, including multianode photomultipliers or Geiger avalanche photodiodes. We present the conceptual design of the focal plane for the camera and results from testing candidate! focal plane sensors.

Image Sensors Enhance Camera Technologies

NASA Technical Reports Server (NTRS)

2010-01-01

In the 1990s, a Jet Propulsion Laboratory team led by Eric Fossum researched ways of improving complementary metal-oxide semiconductor (CMOS) image sensors in order to miniaturize cameras on spacecraft while maintaining scientific image quality. Fossum s team founded a company to commercialize the resulting CMOS active pixel sensor. Now called the Aptina Imaging Corporation, based in San Jose, California, the company has shipped over 1 billion sensors for use in applications such as digital cameras, camera phones, Web cameras, and automotive cameras. Today, one of every three cell phone cameras on the planet feature Aptina s sensor technology.

The iQID Camera: An Ionizing-Radiation Quantum Imaging Detector

DOE PAGES

Miller, Brian W.; Gregory, Stephanie J.; Fuller, Erin S.; ...

2014-06-11

We have developed and tested a novel, ionizing-radiation Quantum Imaging Detector (iQID). This scintillation-based detector was originally developed as a high-resolution gamma-ray imager, called BazookaSPECT, for use in single-photon emission computed tomography (SPECT). Recently, we have investigated the detectors response and imaging potential with other forms of ionizing radiation including alpha, neutron, beta, and fission fragment particles. The detector’s response to a broad range of ionizing radiation has prompted its new title. The principle operation of the iQID camera involves coupling a scintillator to an image intensifier. The scintillation light generated particle interactions is optically amplified by the intensifier andmore » then re-imaged onto a CCD/CMOS camera sensor. The intensifier provides sufficient optical gain that practically any CCD/CMOS camera can be used to image ionizing radiation. Individual particles are identified and their spatial position (to sub-pixel accuracy) and energy are estimated on an event-by-event basis in real time using image analysis algorithms on high-performance graphics processing hardware. Distinguishing features of the iQID camera include portability, large active areas, high sensitivity, and high spatial resolution (tens of microns). Although modest, iQID has energy resolution that is sufficient to discrimate between particles. Additionally, spatial features of individual events can be used for particle discrimination. An important iQID imaging application that has recently been developed is single-particle, real-time digital autoradiography. In conclusion, we present the latest results and discuss potential applications.« less

Development of Camera Electronics for the Advanced Gamma-ray Imaging System (AGIS)

NASA Astrophysics Data System (ADS)

Tajima, Hiroyasu

2009-05-01

AGIS, a next generation of atmospheric Cherenkov telescope arrays, aims to achieve a sensitivity level of a milliCrab for gamma-ray observations in in the energy band of 40 GeV to 100 TeV. Such improvement requires cost reduction of individual components with high reliability in order to equip the order of 100 telescopes necessary to achieve the sensitivity goal. We are exploring several design concepts to reduce the cost of camera electronics while improving their performance. We have developed test systems for some of these concepts and are testing their performance. Here we present test results of the test systems.

An evolution of technologies and applications of gamma imagers in the nuclear cycle industry

DOE Office of Scientific and Technical Information (OSTI.GOV)

Khalil, R. A.; Carrel, F.; Menaa, N.

The tracking of radiation contamination and distribution has become a high priority in the nuclear cycle industry in order to respect the ALARA principle which is a main challenge during decontamination and dismantling activities. To support this need, AREVA/CANBERRA and CEA LIST have been actively carrying out research and development on a gamma-radiation imager. In this paper we will present the new generation of gamma camera, called GAMPIX. This system is based on the Timepix chip, hybridized with a CdTe substrate. A coded mask could be used in order to increase the sensitivity of the camera. Moreover, due to themore » USB connection with a standard computer, this gamma camera is immediately operational and user-friendly. The final system is a very compact gamma camera (global weight is less than 1 kg without any shielding) which could be used as a hand-held device for radioprotection purposes. In this article, we present the main characteristics of this new generation of gamma camera and we expose experimental results obtained during in situ measurements. Even though we present preliminary results the final product is under industrialization phase to address various applications specifications. (authors)« less

21 CFR 892.1100 - Scintillation (gamma) camera.

Code of Federal Regulations, 2011 CFR

2011-04-01

... 21 Food and Drugs 8 2011-04-01 2011-04-01 false Scintillation (gamma) camera. 892.1100 Section 892.1100 Food and Drugs FOOD AND DRUG ADMINISTRATION, DEPARTMENT OF HEALTH AND HUMAN SERVICES (CONTINUED... analysis and display equipment, patient and equipment supports, radionuclide anatomical markers, component...

21 CFR 892.1100 - Scintillation (gamma) camera.

Code of Federal Regulations, 2010 CFR

2010-04-01

... 21 Food and Drugs 8 2010-04-01 2010-04-01 false Scintillation (gamma) camera. 892.1100 Section 892.1100 Food and Drugs FOOD AND DRUG ADMINISTRATION, DEPARTMENT OF HEALTH AND HUMAN SERVICES (CONTINUED... analysis and display equipment, patient and equipment supports, radionuclide anatomical markers, component...

21 CFR 892.1100 - Scintillation (gamma) camera.

Code of Federal Regulations, 2014 CFR

2014-04-01

... 21 Food and Drugs 8 2014-04-01 2014-04-01 false Scintillation (gamma) camera. 892.1100 Section 892.1100 Food and Drugs FOOD AND DRUG ADMINISTRATION, DEPARTMENT OF HEALTH AND HUMAN SERVICES (CONTINUED... analysis and display equipment, patient and equipment supports, radionuclide anatomical markers, component...

Prompt gamma imaging of proton pencil beams at clinical dose rate

NASA Astrophysics Data System (ADS)

Perali, I.; Celani, A.; Bombelli, L.; Fiorini, C.; Camera, F.; Clementel, E.; Henrotin, S.; Janssens, G.; Prieels, D.; Roellinghoff, F.; Smeets, J.; Stichelbaut, F.; Vander Stappen, F.

2014-10-01

In this work, we present experimental results of a prompt gamma camera for real-time proton beam range verification. The detection system features a pixelated Cerium doped lutetium based scintillation crystal, coupled to Silicon PhotoMultiplier arrays, read out by dedicated electronics. The prompt gamma camera uses a knife-edge slit collimator to produce a 1D projection of the beam path in the target on the scintillation detector. We designed the detector to provide high counting statistics and high photo-detection efficiency for prompt gamma rays of several MeV. The slit design favours the counting statistics and could be advantageous in terms of simplicity, reduced cost and limited footprint. We present the description of the realized gamma camera, as well as the results of the characterization of the camera itself in terms of imaging performance. We also present the results of experiments in which a polymethyl methacrylate phantom was irradiated with proton pencil beams in a proton therapy center. A tungsten slit collimator was used and prompt gamma rays were acquired in the 3-6 MeV energy range. The acquisitions were performed with the beam operated at 100 MeV, 160 MeV and 230 MeV, with beam currents at the nozzle exit of several nA. Measured prompt gamma profiles are consistent with the simulations and we reached a precision (2σ) in shift retrieval of 4 mm with 0.5 × 108, 1.4 × 108 and 3.4 × 108 protons at 100, 160 and 230 MeV, respectively. We conclude that the acquisition of prompt gamma profiles for in vivo range verification of proton beam with the developed gamma camera and a slit collimator is feasible in clinical conditions. The compact design of the camera allows its integration in a proton therapy treatment room and further studies will be undertaken to validate the use of this detection system during treatment of real patients.

Commissioning of a new SeHCAT detector and comparison with an uncollimated gamma camera.

PubMed

Taylor, Jonathan C; Hillel, Philip G; Himsworth, John M

2014-10-01

Measurements of SeHCAT (tauroselcholic [75selenium] acid) retention have been used to diagnose bile acid malabsorption for a number of years. In current UK practice the vast majority of centres calculate uptake using an uncollimated gamma camera. Because of ever-increasing demands on gamma camera time, a new 'probe' detector was designed, assembled and commissioned. To validate the system, nine patients were scanned at day 0 and day 7 with both the new probe detector and an uncollimated gamma camera. Commissioning results were largely in line with expectations. Spatial resolution (full-width 95% of maximum) at 1 m was 36.6 cm, the background count rate was 24.7 cps and sensitivity at 1 m was 720.8 cps/MBq. The patient comparison study showed a mean absolute difference in retention measurements of 0.8% between the probe and uncollimated gamma camera, and SD of ± 1.8%. The study demonstrated that it is possible to create a simple, reproducible SeHCAT measurement system using a commercially available scintillation detector. Retention results from the probe closely agreed with those from the uncollimated gamma camera.

The Use of Gamma-Ray Imaging to Improve Portal Monitor Performance

DOE Office of Scientific and Technical Information (OSTI.GOV)

Ziock, Klaus-Peter; Collins, Jeff; Fabris, Lorenzo

2008-01-01

We have constructed a prototype, rapid-deployment portal monitor that uses visible-light and gamma-ray imaging to allow simultaneous monitoring of multiple lanes of traffic from the side of a roadway. Our Roadside Tracker uses automated target acquisition and tracking (TAT) software to identify and track vehicles in visible light images. The field of view of the visible camera overlaps with and is calibrated to that of a one-dimensional gamma-ray imager. The TAT code passes information on when vehicles enter and exit the system field of view and when they cross gamma-ray pixel boundaries. Based on this in-formation, the gamma-ray imager "harvests"more » the gamma-ray data specific to each vehicle, integrating its radiation signature for the entire time that it is in the field of view. In this fashion we are able to generate vehicle-specific radiation signatures and avoid source confusion problems that plague nonimaging approaches to the same problem.« less

Gamma-ray detectors for breast imaging

NASA Astrophysics Data System (ADS)

Williams, Mark B.; Goode, Allen R.; Majewski, Stan; Steinbach, Daniela; Weisenberger, Andrew G.; Wojcik, Randolph F.; Farzanpay, Farzin

1997-07-01

Breast cancer is the most common cancer of American women and is the leading cause of cancer-related death among women aged 15 - 54; however recent years have shown that early detection using x-ray mammography can lead to a high probability of cure. However, because of mammography's low positive predictive value, surgical or core biopsy is typically required for diagnosis. In addition, the low radiographic contrast of many nonpalpable breast masses, particularly among women with radiographically dense breasts, results in an overall rate of 10% to 25% for missed tumors. Nuclear imaging of the breast using single gamma emitters (scintimammography) such as (superscript 99m)Tc, or positron emitters such as F-18- fluorodeoxyglucose (FDG) for positron emission tomography (PET), can provide information on functional or metabolic tumor activity that is complementary to the structural information of x-ray mammography, thereby potentially reducing the number of unnecessary biopsies and missed cancers. This paper summarizes recent data on the efficacy of scintimammography using conventional gamma cameras, and describes the development of dedicated detectors for gamma emission breast imaging. The detectors use new, high density crystal scintillators and large area position sensitive photomultiplier tubes (PSPMTs). Detector design, imaging requirements, and preliminary measured imaging performance are discussed.

Selective-imaging camera

NASA Astrophysics Data System (ADS)

Szu, Harold; Hsu, Charles; Landa, Joseph; Cha, Jae H.; Krapels, Keith A.

2015-05-01

How can we design cameras that image selectively in Full Electro-Magnetic (FEM) spectra? Without selective imaging, we cannot use, for example, ordinary tourist cameras to see through fire, smoke, or other obscurants contributing to creating a Visually Degraded Environment (VDE). This paper addresses a possible new design of selective-imaging cameras at firmware level. The design is consistent with physics of the irreversible thermodynamics of Boltzmann's molecular entropy. It enables imaging in appropriate FEM spectra for sensing through the VDE, and displaying in color spectra for Human Visual System (HVS). We sense within the spectra the largest entropy value of obscurants such as fire, smoke, etc. Then we apply a smart firmware implementation of Blind Sources Separation (BSS) to separate all entropy sources associated with specific Kelvin temperatures. Finally, we recompose the scene using specific RGB colors constrained by the HVS, by up/down shifting Planck spectra at each pixel and time.

[Results of testing of MINISKAN mobile gamma-ray camera and specific features of its design].

PubMed

Utkin, V M; Kumakhov, M A; Blinov, N N; Korsunskiĭ, V N; Fomin, D K; Kolesnikova, N V; Tultaev, A V; Nazarov, A A; Tararukhina, O B

2007-01-01

The main results of engineering, biomedical, and clinical testing of MINISKAN mobile gamma-ray camera are presented. Specific features of the camera hardware and software, as well as the main technical specifications, are described. The gamma-ray camera implements a new technology based on reconstructive tomography, aperture encoding, and digital processing of signals.

Imaging Polarimeter for a Sub-MeV Gamma-Ray All-sky Survey Using an Electron-tracking Compton Camera

NASA Astrophysics Data System (ADS)

Komura, S.; Takada, A.; Mizumura, Y.; Miyamoto, S.; Takemura, T.; Kishimoto, T.; Kubo, H.; Kurosawa, S.; Matsuoka, Y.; Miuchi, K.; Mizumoto, T.; Nakamasu, Y.; Nakamura, K.; Oda, M.; Parker, J. D.; Sawano, T.; Sonoda, S.; Tanimori, T.; Tomono, D.; Yoshikawa, K.

2017-04-01

X-ray and gamma-ray polarimetry is a promising tool to study the geometry and the magnetic configuration of various celestial objects, such as binary black holes or gamma-ray bursts (GRBs). However, statistically significant polarizations have been detected in few of the brightest objects. Even though future polarimeters using X-ray telescopes are expected to observe weak persistent sources, there are no effective approaches to survey transient and serendipitous sources with a wide field of view (FoV). Here we present an electron-tracking Compton camera (ETCC) as a highly sensitive gamma-ray imaging polarimeter. The ETCC provides powerful background rejection and a high modulation factor over an FoV of up to 2π sr thanks to its excellent imaging based on a well-defined point-spread function. Importantly, we demonstrated for the first time the stability of the modulation factor under realistic conditions of off-axis incidence and huge backgrounds using the SPring-8 polarized X-ray beam. The measured modulation factor of the ETCC was 0.65 ± 0.01 at 150 keV for an off-axis incidence with an oblique angle of 30° and was not degraded compared to the 0.58 ± 0.02 at 130 keV for on-axis incidence. These measured results are consistent with the simulation results. Consequently, we found that the satellite-ETCC proposed in Tanimori et al. would provide all-sky surveys of weak persistent sources of 13 mCrab with 10% polarization for a 107 s exposure and over 20 GRBs down to a 6 × 10-6 erg cm-2 fluence and 10% polarization during a one-year observation.

Determination of in vivo behavior of mitomycin C-loaded o/w soybean oil microemulsion and mitomycin C solution via gamma camera imaging.

PubMed

Kotmakçı, Mustafa; Kantarcı, Gülten; Aşıkoğlu, Makbule; Ozkılıç, Hayal; Ertan, Gökhan

2013-09-01

In this study, a microemulsion system was evaluated for delivery of mitomycin C (MMC). To track the distribution of the formulated drug after intravenous administration, radiochemical labeling and gamma scintigraphy imaging were used. The aim was to evaluate a microemulsion system for intravenous delivery of MMC and to compare its in vivo behavior with that of the MMC solution. For microemulsion formulation, soybean oil was used as the oil phase. Lecithin and Tween 80 were surfactants and ethanol was the cosurfactant. To understand the whole body localization of MMC-loaded microemulsion, MMC was labeled with radioactive technetium and gamma scintigraphy was applied for visualization of drug distribution. Radioactivity in the bladder 30 minutes after injection of the MMC solution was observed, according to static gamma camera images. This shows that urinary excretion of the latter starts very soon. On the other hand, no radioactivity appeared in the urinary bladder during the 90 minutes following the administration of MMC-loaded microemulsion. The unabated radioactivity in the liver during the experiment shows that the localization of microemulsion formulation in the liver is stable. In the light of the foregoing, it is suggested that this microemulsion formulation may be an appropriate carrier system for anticancer agents by intravenous delivery in hepatic cancer chemotherapy.

Spacecraft camera image registration

NASA Technical Reports Server (NTRS)

Kamel, Ahmed A. (Inventor); Graul, Donald W. (Inventor); Chan, Fred N. T. (Inventor); Gamble, Donald W. (Inventor)

1987-01-01

A system for achieving spacecraft camera (1, 2) image registration comprises a portion external to the spacecraft and an image motion compensation system (IMCS) portion onboard the spacecraft. Within the IMCS, a computer (38) calculates an image registration compensation signal (60) which is sent to the scan control loops (84, 88, 94, 98) of the onboard cameras (1, 2). At the location external to the spacecraft, the long-term orbital and attitude perturbations on the spacecraft are modeled. Coefficients (K, A) from this model are periodically sent to the onboard computer (38) by means of a command unit (39). The coefficients (K, A) take into account observations of stars and landmarks made by the spacecraft cameras (1, 2) themselves. The computer (38) takes as inputs the updated coefficients (K, A) plus synchronization information indicating the mirror position (AZ, EL) of each of the spacecraft cameras (1, 2), operating mode, and starting and stopping status of the scan lines generated by these cameras (1, 2), and generates in response thereto the image registration compensation signal (60). The sources of periodic thermal errors on the spacecraft are discussed. The system is checked by calculating measurement residuals, the difference between the landmark and star locations predicted at the external location and the landmark and star locations as measured by the spacecraft cameras (1, 2).

The Advanced Gamma-Ray Imaging System (AGIS)

NASA Astrophysics Data System (ADS)

Otte, Nepomuk

The Advanced Gamma-ray Imaging System (AGIS) is a concept for the next generation of imag-ing atmospheric Cherenkov telescope arrays. It has the goal of providing an order of magnitude increase in sensitivity for Very High Energy Gamma-ray ( 100 GeV to 100 TeV) astronomy compared to currently operating arrays such as CANGAROO, HESS, MAGIC, and VERITAS. After an overview of the science such an array would enable, we discuss the development of the components of the telescope system that are required to achieve the sensitivity goal. AGIS stresses improvements in several areas of IACT technology including component reliability as well as exploring cost reduction possibilities in order to achieve its goal. We discuss alterna-tives for the telescopes and positioners: a novel Schwarzschild-Couder telescope offering a wide field of view with a relatively smaller plate scale, and possibilities for rapid slewing in order to address the search for and/or study of Gamma-ray Bursts in the VHE gamma-ray regime. We also discuss options for a high pixel count camera system providing the necessary finer solid angle per pixel and possibilities for a fast topological trigger that would offer improved realtime background rejection and lower energy thresholds.

Design and performance tests of the calorimetric tract of a Compton Camera for small-animals imaging

NASA Astrophysics Data System (ADS)

Rossi, P.; Baldazzi, G.; Battistella, A.; Bello, M.; Bollini, D.; Bonvicini, V.; Fontana, C. L.; Gennaro, G.; Moschini, G.; Navarria, F.; Rashevsky, A.; Uzunov, N.; Zampa, G.; Zampa, N.; Vacchi, A.

2011-02-01

The bio-distribution and targeting capability of pharmaceuticals may be assessed in small animals by imaging gamma-rays emitted from radio-isotope markers. Detectors that exploit the Compton concept allow higher gamma-ray efficiency compared to conventional Anger cameras employing collimators, and feature sub-millimeter spatial resolution and compact geometry. We are developing a Compton Camera that has to address several requirements: the high rates typical of the Compton concept; detection of gamma-rays of different energies that may range from 140 keV ( 99 mTc) to 511 keV ( β+ emitters); presence of gamma and beta radiation with energies up to 2 MeV in case of 188Re. The camera consists of a thin position-sensitive Tracker that scatters the gamma ray, and a second position-sensitive detection system to totally absorb the energy of the scattered photons (Calorimeter). In this paper we present the design and discuss the realization of the calorimetric tract, including the choice of scintillator crystal, pixel size, and detector geometry. Simulations of the gamma-ray trajectories from source to detectors have helped to assess the accuracy of the system and decide on camera design. Crystals of different materials, such as LaBr 3 GSO and YAP, and of different size, in continuous or segmented geometry, have been optically coupled to a multi-anode Hamamatsu H8500 detector, allowing measurements of spatial resolution and efficiency.

Three-dimensional and multienergy gamma-ray simultaneous imaging by using a Si/CdTe Compton camera.

PubMed

Suzuki, Yoshiyuki; Yamaguchi, Mitsutaka; Odaka, Hirokazu; Shimada, Hirofumi; Yoshida, Yukari; Torikai, Kota; Satoh, Takahiro; Arakawa, Kazuo; Kawachi, Naoki; Watanabe, Shigeki; Takeda, Shin'ichiro; Ishikawa, Shin-nosuke; Aono, Hiroyuki; Watanabe, Shin; Takahashi, Tadayuki; Nakano, Takashi

2013-06-01

To develop a silicon (Si) and cadmium telluride (CdTe) imaging Compton camera for biomedical application on the basis of technologies used for astrophysical observation and to test its capacity to perform three-dimensional (3D) imaging. All animal experiments were performed according to the Animal Care and Experimentation Committee (Gunma University, Maebashi, Japan). Flourine 18 fluorodeoxyglucose (FDG), iodine 131 ((131)I) methylnorcholestenol, and gallium 67 ((67)Ga) citrate, separately compacted into micro tubes, were inserted subcutaneously into a Wistar rat, and the distribution of the radioisotope compounds was determined with 3D imaging by using the Compton camera after the rat was sacrificed (ex vivo model). In a separate experiment, indium 111((111)In) chloride and (131)I-methylnorcholestenol were injected into a rat intravenously, and copper 64 ((64)Cu) chloride was administered into the stomach orally just before imaging. The isotope distributions were determined with 3D imaging after sacrifice by means of the list-mode-expectation-maximizing-maximum-likelihood method. The Si/CdTe Compton camera demonstrated its 3D multinuclear imaging capability by separating out the distributions of FDG, (131)I-methylnorcholestenol, and (67)Ga-citrate clearly in a test-tube-implanted ex vivo model. In the more physiologic model with tail vein injection prior to sacrifice, the distributions of (131)I-methylnorcholestenol and (64)Cu-chloride were demonstrated with 3D imaging, and the difference in distribution of the two isotopes was successfully imaged although the accumulation on the image of (111)In-chloride was difficult to visualize because of blurring at the low-energy region. The Si/CdTe Compton camera clearly resolved the distribution of multiple isotopes in 3D imaging and simultaneously in the ex vivo model.

Electron-tracking Compton gamma-ray camera for small animal and phantom imaging

NASA Astrophysics Data System (ADS)

Kabuki, Shigeto; Kimura, Hiroyuki; Amano, Hiroo; Nakamoto, Yuji; Kubo, Hidetoshi; Miuchi, Kentaro; Kurosawa, Shunsuke; Takahashi, Michiaki; Kawashima, Hidekazu; Ueda, Masashi; Okada, Tomohisa; Kubo, Atsushi; Kunieda, Etuso; Nakahara, Tadaki; Kohara, Ryota; Miyazaki, Osamu; Nakazawa, Tetsuo; Shirahata, Takashi; Yamamoto, Etsuji; Ogawa, Koichi; Togashi, Kaori; Saji, Hideo; Tanimori, Toru

2010-11-01

We have developed an electron-tracking Compton camera (ETCC) for medical use. Our ETCC has a wide energy dynamic range (200-1300 keV) and wide field of view (3 sr), and thus has potential for advanced medical use. To evaluate the ETCC, we imaged the head (brain) and bladder of mice that had been administered with F-18-FDG. We also imaged the head and thyroid gland of mice using double tracers of F-18-FDG and I-131 ions.

Imaging Polarimeter for a Sub-MeV Gamma-Ray All-sky Survey Using an Electron-tracking Compton Camera

DOE Office of Scientific and Technical Information (OSTI.GOV)

Komura, S.; Takada, A.; Mizumura, Y.

2017-04-10

X-ray and gamma-ray polarimetry is a promising tool to study the geometry and the magnetic configuration of various celestial objects, such as binary black holes or gamma-ray bursts (GRBs). However, statistically significant polarizations have been detected in few of the brightest objects. Even though future polarimeters using X-ray telescopes are expected to observe weak persistent sources, there are no effective approaches to survey transient and serendipitous sources with a wide field of view (FoV). Here we present an electron-tracking Compton camera (ETCC) as a highly sensitive gamma-ray imaging polarimeter. The ETCC provides powerful background rejection and a high modulation factormore » over an FoV of up to 2 π sr thanks to its excellent imaging based on a well-defined point-spread function. Importantly, we demonstrated for the first time the stability of the modulation factor under realistic conditions of off-axis incidence and huge backgrounds using the SPring-8 polarized X-ray beam. The measured modulation factor of the ETCC was 0.65 ± 0.01 at 150 keV for an off-axis incidence with an oblique angle of 30° and was not degraded compared to the 0.58 ± 0.02 at 130 keV for on-axis incidence. These measured results are consistent with the simulation results. Consequently, we found that the satellite-ETCC proposed in Tanimori et al. would provide all-sky surveys of weak persistent sources of 13 mCrab with 10% polarization for a 10{sup 7} s exposure and over 20 GRBs down to a 6 × 10{sup −6} erg cm{sup −2} fluence and 10% polarization during a one-year observation.« less

Gamma camera dual imaging with a somatostatin receptor and thymidine kinase after gene transfer with a bicistronic adenovirus in mice.

PubMed

Zinn, Kurt R; Chaudhuri, Tandra R; Krasnykh, Victor N; Buchsbaum, Donald J; Belousova, Natalya; Grizzle, William E; Curiel, David T; Rogers, Buck E

2002-05-01

To compare two systems for assessing gene transfer to cancer cells and xenograft tumors with noninvasive gamma camera imaging. A replication-incompetent adenovirus encoding the human type 2 somatostatin receptor (hSSTr2) and the herpes simplex virus thymidine kinase (TK) enzyme (Ad-hSSTr2-TK) was constructed. A-427 human lung cancer cells were infected in vitro and mixed with uninfected cells at different ratios. A-427 tumors in nude mice (n = 23) were injected with 1 x 10(6) to 5 x 10(8) plaque-forming units (pfu) of Ad-hSSTr2-TK. The expressed hSSTr2 and TK proteins were imaged owing to internally bound, or trapped, technetium 99m ((99m)Tc)-labeled hSSTr2-binding peptide (P2045) and radioiodinated 2'-deoxy-2'-fluoro-beta-D-arabinofuranosyl-5-iodouracil (FIAU), respectively. Iodine 125 ((125)I)-labeled FIAU was used in vitro and iodine 131 ((131)I)-labeled FIAU, in vivo. The (99m)Tc-labeled P2045 and (125)I- or (131)I-labeled FIAU were imaged simultaneously with different window settings with an Anger gamma camera. Treatment effects were tested with analysis of variance. Infected cells in culture trapped (125)I-labeled FIAU and (99m)Tc-labeled P2045; uptake correlated with the percentage of Ad-hSSTr2-TK-positive cells. For 100% of infected cells, 24% +/- 0.4 (mean +/- SD) of the added (99m)Tc-labeled P2045 was trapped, which is significantly lower (P <.05) than the 40% +/- 2 of (125)I-labeled FIAU that was trapped. For the highest Ad-hSSTr2-TK tumor dose (5 x 10(8) pfu), the uptake of (99m)Tc-labeled P2045 was 11.1% +/- 2.9 of injected dose per gram of tumor (thereafter, dose per gram), significantly higher (P <.05) than the uptake of (131)I-labeled FIAU at 1.6% +/- 0.4 dose per gram. (99m)Tc-labeled P2045 imaging consistently depicted hSSTr2 gene transfer in tumors at all adenovirus doses. Tumor uptake of (99m)Tc-labeled P2045 positively correlated with Ad-hSSTr2-TK dose; (131)I-labeled FIAU tumor uptake did not correlate with vector dose. The hSSTr2 and TK

Feasibility study of a gamma camera for monitoring nuclear materials in the PRIDE facility

NASA Astrophysics Data System (ADS)

Jo, Woo Jin; Kim, Hyun-Il; An, Su Jung; Lee, Chae Young; Song, Han-Kyeol; Chung, Yong Hyun; Shin, Hee-Sung; Ahn, Seong-Kyu; Park, Se-Hwan

2014-05-01

The Korea Atomic Energy Research Institute (KAERI) has been developing pyroprocessing technology, in which actinides are recovered together with plutonium. There is no pure plutonium stream in the process, so it has an advantage of proliferation resistance. Tracking and monitoring of nuclear materials through the pyroprocess can significantly improve the transparency of the operation and safeguards. An inactive engineering-scale integrated pyroprocess facility, which is the PyRoprocess Integrated inactive DEmonstration (PRIDE) facility, was constructed to demonstrate engineering-scale processes and the integration of each unit process. the PRIDE facility may be a good test bed to investigate the feasibility of a nuclear material monitoring system. In this study, we designed a gamma camera system for nuclear material monitoring in the PRIDE facility by using a Monte Carlo simulation, and we validated the feasibility of this system. Two scenarios, according to locations of the gamma camera, were simulated using GATE (GEANT4 Application for Tomographic Emission) version 6. A prototype gamma camera with a diverging-slat collimator was developed, and the simulated and experimented results agreed well with each other. These results indicate that a gamma camera to monitor the nuclear material in the PRIDE facility can be developed.

Development of compact Compton camera for 3D image reconstruction of radioactive contamination

NASA Astrophysics Data System (ADS)

Sato, Y.; Terasaka, Y.; Ozawa, S.; Nakamura Miyamura, H.; Kaburagi, M.; Tanifuji, Y.; Kawabata, K.; Torii, T.

2017-11-01

The Fukushima Daiichi Nuclear Power Station (FDNPS), operated by Tokyo Electric Power Company Holdings, Inc., went into meltdown after the large tsunami caused by the Great East Japan Earthquake of March 11, 2011. Very large amounts of radionuclides were released from the damaged plant. Radiation distribution measurements inside FDNPS buildings are indispensable to execute decommissioning tasks in the reactor buildings. We have developed a compact Compton camera to measure the distribution of radioactive contamination inside the FDNPS buildings three-dimensionally (3D). The total weight of the Compton camera is lower than 1.0 kg. The gamma-ray sensor of the Compton camera employs Ce-doped GAGG (Gd3Al2Ga3O12) scintillators coupled with a multi-pixel photon counter. Angular correction of the detection efficiency of the Compton camera was conducted. Moreover, we developed a 3D back-projection method using the multi-angle data measured with the Compton camera. We successfully observed 3D radiation images resulting from the two 137Cs radioactive sources, and the image of the 9.2 MBq source appeared stronger than that of the 2.7 MBq source.

Impact of intense x-ray pulses on a NaI(Tl)-based gamma camera

NASA Astrophysics Data System (ADS)

Koppert, W. J. C.; van der Velden, S.; Steenbergen, J. H. L.; de Jong, H. W. A. M.

2018-03-01

In SPECT/CT systems x-ray and γ-ray imaging is performed sequentially. Simultaneous acquisition may have advantages, for instance in interventional settings. However, this may expose a gamma camera to relatively high x-ray doses and deteriorate its functioning. We studied the NaI(Tl) response to x-ray pulses with a photodiode, PMT and gamma camera, respectively. First, we exposed a NaI(Tl)-photodiode assembly to x-ray pulses to investigate potential crystal afterglow. Next, we exposed a NaI(Tl)-PMT assembly to 10 ms LED pulses (mimicking x-ray pulses) and measured the response to flashing LED probe-pulses (mimicking γ-pulses). We then exposed the assembly to x-ray pulses, with detector entrance doses of up to 9 nGy/pulse, and analysed the response for γ-pulse variations. Finally, we studied the response of a Siemens Diacam gamma camera to γ-rays while exposed to x-ray pulses. X-ray exposure of the crystal, read out with a photodiode, revealed 15% afterglow fraction after 3 ms. The NaI(Tl)-PMT assembly showed disturbances up to 10 ms after 10 ms LED exposure. After x-ray exposure however, responses showed elevated baselines, with 60 ms decay-time. Both for x-ray and LED exposure and after baseline subtraction, probe-pulse analysis revealed disturbed pulse height measurements shortly after exposure. X-ray exposure of the Diacam corroborated the elementary experiments. Up to 50 ms after an x-ray pulse, no events are registered, followed by apparent energy elevations up to 100 ms after exposure. Limiting the dose to 0.02 nGy/pulse prevents detrimental effects. Conventional gamma cameras exhibit substantial dead-time and mis-registration of photon energies up to 100 ms after intense x-ray pulses. This is due PMT limitations and due to afterglow in the crystal. Using PMTs with modified circuitry, we show that deteriorative afterglow effects can be reduced without noticeable effects on the PMT performance, up to x-ray pulse doses of 1 nGy.

Assessment of right ventricular function with nonimaging first pass ventriculography and comparison of results with gamma camera studies.

PubMed

Zhang, Z; Liu, X J; Liu, Y Z; Lu, P; Crawley, J C; Lahiri, A

1990-08-01

A new technique has been developed for measuring right ventricular function by nonimaging first pass ventriculography. The right ventricular ejection fraction (RVEF) obtained by non-imaging first pass ventriculography was compared with that obtained by gamma camera first pass and equilibrium ventriculography. The data has demonstrated that the correlation of RVEFs obtained by the nonimaging nuclear cardiac probe and by gamma camera first pass ventriculography in 15 subjects was comparable (r = 0.93). There was also a good correlation between RVEFs obtained by the nonimaging nuclear probe and by equilibrium gated blood pool studies in 33 subjects (r = 0.89). RVEF was significantly reduced in 15 patients with right ventricular and/or inferior myocardial infarction compared to normal subjects (28 +/- 9% v. 45 +/- 9%). The data suggests that nonimaging probes may be used for assessing right ventricular function accurately.

Temporal Imaging CeBr3 Compton Camera: A New Concept for Nuclear Decommissioning and Nuclear Waste Management

NASA Astrophysics Data System (ADS)

Iltis, A.; Snoussi, H.; Magalhaes, L. Rodrigues de; Hmissi, M. Z.; Zafiarifety, C. Tata; Tadonkeng, G. Zeufack; Morel, C.

2018-01-01

During nuclear decommissioning or waste management operations, a camera that could make an image of the contamination field and identify and quantify the contaminants would be a great progress. Compton cameras have been proposed, but their limited efficiency for high energy gamma rays and their cost have severely limited their application. Our objective is to promote a Compton camera for the energy range (200 keV - 2 MeV) that uses fast scintillating crystals and a new concept for locating scintillation event: Temporal Imaging. Temporal Imaging uses monolithic plates of fast scintillators and measures photons time of arrival distribution in order to locate each gamma ray with a high precision in space (X,Y,Z), time (T) and energy (E). This provides a native estimation of the depth of interaction (Z) of every detected gamma ray. This also allows a time correction for the propagation time of scintillation photons inside the crystal, therefore resulting in excellent time resolution. The high temporal resolution of the system makes it possible to veto quite efficiently background by using narrow time coincidence (< 300 ps). It is also possible to reconstruct the direction of propagation of the photons inside the detector using timing constraints. The sensitivity of our system is better than 1 nSv/h in a 60 s acquisition with a 22Na source. The project TEMPORAL is funded by the ANDRA/PAI under the grant No. RTSCNADAA160019.

Studies on a silicon-photomultiplier-based camera for Imaging Atmospheric Cherenkov Telescopes

NASA Astrophysics Data System (ADS)

Arcaro, C.; Corti, D.; De Angelis, A.; Doro, M.; Manea, C.; Mariotti, M.; Rando, R.; Reichardt, I.; Tescaro, D.

2017-12-01

Imaging Atmospheric Cherenkov Telescopes (IACTs) represent a class of instruments which are dedicated to the ground-based observation of cosmic VHE gamma ray emission based on the detection of the Cherenkov radiation produced in the interaction of gamma rays with the Earth atmosphere. One of the key elements of such instruments is a pixelized focal-plane camera consisting of photodetectors. To date, photomultiplier tubes (PMTs) have been the common choice given their high photon detection efficiency (PDE) and fast time response. Recently, silicon photomultipliers (SiPMs) are emerging as an alternative. This rapidly evolving technology has strong potential to become superior to that based on PMTs in terms of PDE, which would further improve the sensitivity of IACTs, and see a price reduction per square millimeter of detector area. We are working to develop a SiPM-based module for the focal-plane cameras of the MAGIC telescopes to probe this technology for IACTs with large focal plane cameras of an area of few square meters. We will describe the solutions we are exploring in order to balance a competitive performance with a minimal impact on the overall MAGIC camera design using ray tracing simulations. We further present a comparative study of the overall light throughput based on Monte Carlo simulations and considering the properties of the major hardware elements of an IACT.

Camera Trajectory fromWide Baseline Images

NASA Astrophysics Data System (ADS)

Havlena, M.; Torii, A.; Pajdla, T.

2008-09-01

Camera trajectory estimation, which is closely related to the structure from motion computation, is one of the fundamental tasks in computer vision. Reliable camera trajectory estimation plays an important role in 3D reconstruction, self localization, and object recognition. There are essential issues for a reliable camera trajectory estimation, for instance, choice of the camera and its geometric projection model, camera calibration, image feature detection and description, and robust 3D structure computation. Most of approaches rely on classical perspective cameras because of the simplicity of their projection models and ease of their calibration. However, classical perspective cameras offer only a limited field of view, and thus occlusions and sharp camera turns may cause that consecutive frames look completely different when the baseline becomes longer. This makes the image feature matching very difficult (or impossible) and the camera trajectory estimation fails under such conditions. These problems can be avoided if omnidirectional cameras, e.g. a fish-eye lens convertor, are used. The hardware which we are using in practice is a combination of Nikon FC-E9 mounted via a mechanical adaptor onto a Kyocera Finecam M410R digital camera. Nikon FC-E9 is a megapixel omnidirectional addon convertor with 180° view angle which provides images of photographic quality. Kyocera Finecam M410R delivers 2272×1704 images at 3 frames per second. The resulting combination yields a circular view of diameter 1600 pixels in the image. Since consecutive frames of the omnidirectional camera often share a common region in 3D space, the image feature matching is often feasible. On the other hand, the calibration of these cameras is non-trivial and is crucial for the accuracy of the resulting 3D reconstruction. We calibrate omnidirectional cameras off-line using the state-of-the-art technique and Mičušík's two-parameter model, that links the radius of the image point r to the

Upgraded cameras for the HESS imaging atmospheric Cherenkov telescopes

NASA Astrophysics Data System (ADS)

Giavitto, Gianluca; Ashton, Terry; Balzer, Arnim; Berge, David; Brun, Francois; Chaminade, Thomas; Delagnes, Eric; Fontaine, Gérard; Füßling, Matthias; Giebels, Berrie; Glicenstein, Jean-François; Gräber, Tobias; Hinton, James; Jahnke, Albert; Klepser, Stefan; Kossatz, Marko; Kretzschmann, Axel; Lefranc, Valentin; Leich, Holger; Lüdecke, Hartmut; Lypova, Iryna; Manigot, Pascal; Marandon, Vincent; Moulin, Emmanuel; de Naurois, Mathieu; Nayman, Patrick; Penno, Marek; Ross, Duncan; Salek, David; Schade, Markus; Schwab, Thomas; Simoni, Rachel; Stegmann, Christian; Steppa, Constantin; Thornhill, Julian; Toussnel, François

2016-08-01

The High Energy Stereoscopic System (H.E.S.S.) is an array of five imaging atmospheric Cherenkov telescopes, sensitive to cosmic gamma rays of energies between 30 GeV and several tens of TeV. Four of them started operations in 2003 and their photomultiplier tube (PMT) cameras are currently undergoing a major upgrade, with the goals of improving the overall performance of the array and reducing the failure rate of the ageing systems. With the exception of the 960 PMTs, all components inside the camera have been replaced: these include the readout and trigger electronics, the power, ventilation and pneumatic systems and the control and data acquisition software. New designs and technical solutions have been introduced: the readout makes use of the NECTAr analog memory chip, which samples and stores the PMT signals and was developed for the Cherenkov Telescope Array (CTA). The control of all hardware subsystems is carried out by an FPGA coupled to an embedded ARM computer, a modular design which has proven to be very fast and reliable. The new camera software is based on modern C++ libraries such as Apache Thrift, ØMQ and Protocol buffers, offering very good performance, robustness, flexibility and ease of development. The first camera was upgraded in 2015, the other three cameras are foreseen to follow in fall 2016. We describe the design, the performance, the results of the tests and the lessons learned from the first upgraded H.E.S.S. camera.

Focal Plane Detectors for the Advanced Gamma-Ray Imaging System (AGIS)

NASA Astrophysics Data System (ADS)

Wagner, Robert G.; AGIS Photodetector Group; Byrum, K.; Drake, G.; Falcone, A.; Funk, S.; Horan, D.; Mukherjee, R.; Tajima, H.; Williams, D.

2008-03-01

The Advanced Gamma-Ray Imaging System (AGIS) is a concept for the next generation observatory in ground-based very high energy gamma-ray astronomy. It is being designed to achieve a significant improvement in sensitivity compared to current Imaging Air Cherenkov Telescope (IACT) Arrays. One of the main requirements in order that AGIS fulfill this goal will be to achieve higher angular resolution than current IACTs. Simulations show that a substantial improvement in angular resolution may be achieved if the pixel size is reduced to less than 0.05 deg, i.e. two to three times smaller than the pixel size of current IACT cameras. With finer pixelation and the plan to deploy on the order of 100 telescopes in the AGIS array, the channel count will exceed 1,000,000 imaging pixels. High uniformity and long mean time-to-failure will be important aspects of a successful photodetector technology choice. Here we present alternatives being considered for AGIS, including both silicon photomultipliers (SiPMs) and multi-anode photomultipliers (MAPMTs). Results from laboratory testing of MAPMTs and SiPMs are presented along with results from the first incorporation of these devices in cameras on test bed Cherenkov telescopes.

Design of Dual-Road Transportable Portal Monitoring System for Visible Light and Gamma-Ray Imaging

DOE Office of Scientific and Technical Information (OSTI.GOV)

Karnowski, Thomas Paul; Cunningham, Mark F; Goddard Jr, James Samuel

2010-01-01

The use of radiation sensors as portal monitors is increasing due to heightened concerns over the smuggling of fissile material. Transportable systems that can detect significant quantities of fissile material that might be present in vehicular traffic are of particular interest, especially if they can be rapidly deployed to different locations. To serve this application, we have constructed a rapid-deployment portal monitor that uses visible-light and gamma-ray imaging to allow simultaneous monitoring of multiple lanes of traffic from the side of a roadway. The system operation uses machine vision methods on the visible-light images to detect vehicles as they entermore » and exit the field of view and to measure their position in each frame. The visible-light and gamma-ray cameras are synchronized which allows the gamma-ray imager to harvest gamma-ray data specific to each vehicle, integrating its radiation signature for the entire time that it is in the field of view. Thus our system creates vehicle-specific radiation signatures and avoids source confusion problems that plague non-imaging approaches to the same problem. Our current prototype instrument was designed for measurement of upto five lanes of freeway traffic with a pair of instruments, one on either side of the roadway. Stereoscopic cameras are used with a third alignment camera for motion compensation and are mounted on a 50 deployable mast. In this paper we discuss the design considerations for the machine-vision system, the algorithms used for vehicle detection and position estimates, and the overall architecture of the system. We also discuss system calibration for rapid deployment. We conclude with notes on preliminary performance and deployment.« less

Design of dual-road transportable portal monitoring system for visible light and gamma-ray imaging

NASA Astrophysics Data System (ADS)

Karnowski, Thomas P.; Cunningham, Mark F.; Goddard, James S.; Cheriyadat, Anil M.; Hornback, Donald E.; Fabris, Lorenzo; Kerekes, Ryan A.; Ziock, Klaus-Peter; Bradley, E. Craig; Chesser, J.; Marchant, W.

2010-04-01

The use of radiation sensors as portal monitors is increasing due to heightened concerns over the smuggling of fissile material. Transportable systems that can detect significant quantities of fissile material that might be present in vehicular traffic are of particular interest, especially if they can be rapidly deployed to different locations. To serve this application, we have constructed a rapid-deployment portal monitor that uses visible-light and gamma-ray imaging to allow simultaneous monitoring of multiple lanes of traffic from the side of a roadway. The system operation uses machine vision methods on the visible-light images to detect vehicles as they enter and exit the field of view and to measure their position in each frame. The visible-light and gamma-ray cameras are synchronized which allows the gamma-ray imager to harvest gamma-ray data specific to each vehicle, integrating its radiation signature for the entire time that it is in the field of view. Thus our system creates vehicle-specific radiation signatures and avoids source confusion problems that plague non-imaging approaches to the same problem. Our current prototype instrument was designed for measurement of upto five lanes of freeway traffic with a pair of instruments, one on either side of the roadway. Stereoscopic cameras are used with a third "alignment" camera for motion compensation and are mounted on a 50' deployable mast. In this paper we discuss the design considerations for the machine-vision system, the algorithms used for vehicle detection and position estimates, and the overall architecture of the system. We also discuss system calibration for rapid deployment. We conclude with notes on preliminary performance and deployment.

A feasibility study of an integrated NIR/gamma/visible imaging system for endoscopic sentinel lymph node mapping.

PubMed

Kang, Han Gyu; Lee, Ho-Young; Kim, Kyeong Min; Song, Seong-Hyun; Hong, Gun Chul; Hong, Seong Jong

2017-01-01

The aim of this study is to integrate NIR, gamma, and visible imaging tools into a single endoscopic system to overcome the limitation of NIR using gamma imaging and to demonstrate the feasibility of endoscopic NIR/gamma/visible fusion imaging for sentinel lymph node (SLN) mapping with a small animal. The endoscopic NIR/gamma/visible imaging system consists of a tungsten pinhole collimator, a plastic focusing lens, a BGO crystal (11 × 11 × 2 mm 3 ), a fiber-optic taper (front = 11 × 11 mm 2 , end = 4 × 4 mm 2 ), a 122-cm long endoscopic fiber bundle, an NIR emission filter, a relay lens, and a CCD camera. A custom-made Derenzo-like phantom filled with a mixture of 99m Tc and indocyanine green (ICG) was used to assess the spatial resolution of the NIR and gamma images. The ICG fluorophore was excited using a light-emitting diode (LED) with an excitation filter (723-758 nm), and the emitted fluorescence photons were detected with an emission filter (780-820 nm) for a duration of 100 ms. Subsequently, the 99m Tc distribution in the phantom was imaged for 3 min. The feasibility of in vivo SLN mapping with a mouse was investigated by injecting a mixture of 99m Tc-antimony sulfur colloid (12 MBq) and ICG (0.1 mL) into the right paw of the mouse (C57/B6) subcutaneously. After one hour, NIR, gamma, and visible images were acquired sequentially. Subsequently, the dissected SLN was imaged in the same way as the in vivo SLN mapping. The NIR, gamma, and visible images of the Derenzo-like phantom can be obtained with the proposed endoscopic imaging system. The NIR/gamma/visible fusion image of the SLN showed a good correlation among the NIR, gamma, and visible images both for the in vivo and ex vivo imaging. We demonstrated the feasibility of the integrated NIR/gamma/visible imaging system using a single endoscopic fiber bundle. In future, we plan to investigate miniaturization of the endoscope head and simultaneous NIR/gamma/visible imaging with

Geometric rectification of camera-captured document images.

PubMed

Liang, Jian; DeMenthon, Daniel; Doermann, David

2008-04-01

Compared to typical scanners, handheld cameras offer convenient, flexible, portable, and non-contact image capture, which enables many new applications and breathes new life into existing ones. However, camera-captured documents may suffer from distortions caused by non-planar document shape and perspective projection, which lead to failure of current OCR technologies. We present a geometric rectification framework for restoring the frontal-flat view of a document from a single camera-captured image. Our approach estimates 3D document shape from texture flow information obtained directly from the image without requiring additional 3D/metric data or prior camera calibration. Our framework provides a unified solution for both planar and curved documents and can be applied in many, especially mobile, camera-based document analysis applications. Experiments show that our method produces results that are significantly more OCR compatible than the original images.

An evolution of image source camera attribution approaches.

PubMed

Jahanirad, Mehdi; Wahab, Ainuddin Wahid Abdul; Anuar, Nor Badrul

2016-05-01

Camera attribution plays an important role in digital image forensics by providing the evidence and distinguishing characteristics of the origin of the digital image. It allows the forensic analyser to find the possible source camera which captured the image under investigation. However, in real-world applications, these approaches have faced many challenges due to the large set of multimedia data publicly available through photo sharing and social network sites, captured with uncontrolled conditions and undergone variety of hardware and software post-processing operations. Moreover, the legal system only accepts the forensic analysis of the digital image evidence if the applied camera attribution techniques are unbiased, reliable, nondestructive and widely accepted by the experts in the field. The aim of this paper is to investigate the evolutionary trend of image source camera attribution approaches from fundamental to practice, in particular, with the application of image processing and data mining techniques. Extracting implicit knowledge from images using intrinsic image artifacts for source camera attribution requires a structured image mining process. In this paper, we attempt to provide an introductory tutorial on the image processing pipeline, to determine the general classification of the features corresponding to different components for source camera attribution. The article also reviews techniques of the source camera attribution more comprehensively in the domain of the image forensics in conjunction with the presentation of classifying ongoing developments within the specified area. The classification of the existing source camera attribution approaches is presented based on the specific parameters, such as colour image processing pipeline, hardware- and software-related artifacts and the methods to extract such artifacts. The more recent source camera attribution approaches, which have not yet gained sufficient attention among image forensics

Applications of iQID cameras

NASA Astrophysics Data System (ADS)

Han, Ling; Miller, Brian W.; Barrett, Harrison H.; Barber, H. Bradford; Furenlid, Lars R.

2017-09-01

iQID is an intensified quantum imaging detector developed in the Center for Gamma-Ray Imaging (CGRI). Originally called BazookaSPECT, iQID was designed for high-resolution gamma-ray imaging and preclinical gamma-ray single-photon emission computed tomography (SPECT). With the use of a columnar scintillator, an image intensifier and modern CCD/CMOS sensors, iQID cameras features outstanding intrinsic spatial resolution. In recent years, many advances have been achieved that greatly boost the performance of iQID, broadening its applications to cover nuclear and particle imaging for preclinical, clinical and homeland security settings. This paper presents an overview of the recent advances of iQID technology and its applications in preclinical and clinical scintigraphy, preclinical SPECT, particle imaging (alpha, neutron, beta, and fission fragment), and digital autoradiography.

Metabolic cardiac imaging in severe coronary disease: assessment of viability with iodine-123-iodophenylpentadecanoic acid and multicrystal gamma camera, and correlation with biopsy.

PubMed

Murray, G; Schad, N; Ladd, W; Allie, D; vander Zwagg, R; Avet, P; Rockett, J

1992-07-01

Fifteen patients with coronary disease and resting left ventricular ejection fractions of less than or equal to 0.35 underwent resting metabolic cardiac imaging utilizing 1 mCi [123I]iodophenylpentadecanoic acid (IPPA) intravenously and a multicrystal gamma camera. Parametric images of regional rates of IPPA clearance and accumulation were generated. Forty-two vascular territories (22 infarcted) were evaluated by metabolic imaging as well as transmural myocardial biopsy. Despite resting akinesis or dyskinesis in 20/22 (91%) infarcted territories, 16/22 (73%) of these territories were metabolically viable. Transmural myocardial biopsies in all patients (43 sites, 42 vascular territories) during coronary bypass surgery confirmed IPPA results in 39/43 patients (91%). When compared to biopsy, scan sensitivity for viability was 33/36 (92%) with a specificity of 6/7 (86%). Eighty percent of bypassed, infarcted but IPPA viable segments demonstrated improved regional systolic wall motion postoperatively as assessed by exercise radionuclide angiography. We conclude resting IPPA imaging identifies viable myocardium, thereby providing a safe, cost-effective technique for myocardial viability assessment.

Portable gamma camera guidance in sentinel lymph node biopsy: prospective observational study of consecutive cases.

PubMed

Peral Rubio, F; de La Riva, P; Moreno-Ramírez, D; Ferrándiz-Pulido, L

2015-06-01

Sentinel lymph node biopsy is the most important tool available for node staging in patients with melanoma. To analyze sentinel lymph node detection and dissection with radio guidance from a portable gamma camera. To assess the number of complications attributable to this biopsy technique. Prospective observational study of a consecutive series of patients undergoing radioguided sentinel lymph node biopsy. We analyzed agreement between nodes detected by presurgical lymphography, those detected by the gamma camera, and those finally dissected. A total of 29 patients (17 women [62.5%] and 12 men [37.5%]) were enrolled. The mean age was 52.6 years (range, 26-82 years). The sentinel node was dissected from all patients; secondary nodes were dissected from some. In 16 cases (55.2%), there was agreement between the number of nodes detected by lymphography, those detected by the gamma camera, and those finally dissected. The only complications observed were seromas (3.64%). No cases of wound dehiscence, infection, hematoma, or hemorrhage were observed. Portable gamma-camera radio guidance may be of use in improving the detection and dissection of sentinel lymph nodes and may also reduce complications. These goals are essential in a procedure whose purpose is melanoma staging. Copyright © 2014 Elsevier España, S.L.U. and AEDV. All rights reserved.

Dual-modality imaging with a ultrasound-gamma device for oncology

NASA Astrophysics Data System (ADS)

Polito, C.; Pellegrini, R.; Cinti, M. N.; De Vincentis, G.; Lo Meo, S.; Fabbri, A.; Bennati, P.; Cencelli, V. Orsolini; Pani, R.

2018-06-01

Recently, dual-modality systems have been developed, aimed to correlate anatomical and functional information, improving disease localization and helping oncological or surgical treatments. Moreover, due to the growing interest in handheld detectors for preclinical trials or small animal imaging, in this work a new dual modality integrated device, based on a Ultrasounds probe and a small Field of View Single Photon Emission gamma camera, is proposed.

Performance Test Data Analysis of Scintillation Cameras

NASA Astrophysics Data System (ADS)

Demirkaya, Omer; Mazrou, Refaat Al

2007-10-01

In this paper, we present a set of image analysis tools to calculate the performance parameters of gamma camera systems from test data acquired according to the National Electrical Manufacturers Association NU 1-2001 guidelines. The calculation methods are either completely automated or require minimal user interaction; minimizing potential human errors. The developed methods are robust with respect to varying conditions under which these tests may be performed. The core algorithms have been validated for accuracy. They have been extensively tested on images acquired by the gamma cameras from different vendors. All the algorithms are incorporated into a graphical user interface that provides a convenient way to process the data and report the results. The entire application has been developed in MATLAB programming environment and is compiled to run as a stand-alone program. The developed image analysis tools provide an automated, convenient and accurate means to calculate the performance parameters of gamma cameras and SPECT systems. The developed application is available upon request for personal or non-commercial uses. The results of this study have been partially presented in Society of Nuclear Medicine Annual meeting as an InfoSNM presentation.

Plenoptic camera image simulation for reconstruction algorithm verification

NASA Astrophysics Data System (ADS)

Schwiegerling, Jim

2014-09-01

Plenoptic cameras have emerged in recent years as a technology for capturing light field data in a single snapshot. A conventional digital camera can be modified with the addition of a lenslet array to create a plenoptic camera. Two distinct camera forms have been proposed in the literature. The first has the camera image focused onto the lenslet array. The lenslet array is placed over the camera sensor such that each lenslet forms an image of the exit pupil onto the sensor. The second plenoptic form has the lenslet array relaying the image formed by the camera lens to the sensor. We have developed a raytracing package that can simulate images formed by a generalized version of the plenoptic camera. Several rays from each sensor pixel are traced backwards through the system to define a cone of rays emanating from the entrance pupil of the camera lens. Objects that lie within this cone are integrated to lead to a color and exposure level for that pixel. To speed processing three-dimensional objects are approximated as a series of planes at different depths. Repeating this process for each pixel in the sensor leads to a simulated plenoptic image on which different reconstruction algorithms can be tested.

NV-CMOS HD camera for day/night imaging

NASA Astrophysics Data System (ADS)

Vogelsong, T.; Tower, J.; Sudol, Thomas; Senko, T.; Chodelka, D.

2014-06-01

SRI International (SRI) has developed a new multi-purpose day/night video camera with low-light imaging performance comparable to an image intensifier, while offering the size, weight, ruggedness, and cost advantages enabled by the use of SRI's NV-CMOS HD digital image sensor chip. The digital video output is ideal for image enhancement, sharing with others through networking, video capture for data analysis, or fusion with thermal cameras. The camera provides Camera Link output with HD/WUXGA resolution of 1920 x 1200 pixels operating at 60 Hz. Windowing to smaller sizes enables operation at higher frame rates. High sensitivity is achieved through use of backside illumination, providing high Quantum Efficiency (QE) across the visible and near infrared (NIR) bands (peak QE <90%), as well as projected low noise (<2h+) readout. Power consumption is minimized in the camera, which operates from a single 5V supply. The NVCMOS HD camera provides a substantial reduction in size, weight, and power (SWaP) , ideal for SWaP-constrained day/night imaging platforms such as UAVs, ground vehicles, fixed mount surveillance, and may be reconfigured for mobile soldier operations such as night vision goggles and weapon sights. In addition the camera with the NV-CMOS HD imager is suitable for high performance digital cinematography/broadcast systems, biofluorescence/microscopy imaging, day/night security and surveillance, and other high-end applications which require HD video imaging with high sensitivity and wide dynamic range. The camera comes with an array of lens mounts including C-mount and F-mount. The latest test data from the NV-CMOS HD camera will be presented.

Tumor dosimetry for I-131 trastuzumab therapy in a Her2+ NCI N87 xenograft mouse model using the Siemens SYMBIA E gamma camera with a pinhole collimator

NASA Astrophysics Data System (ADS)

Lee, Young Sub; Kim, Jin Su; Deuk Cho, Kyung; Kang, Joo Hyun; Moo Lim, Sang

2015-07-01

We performed imaging and therapy using I-131 trastuzumab and a pinhole collimator attached to a conventional gamma camera for human use in a mouse model. The conventional clinical gamma camera with a 2-mm radius-sized pinhole collimator was used for monitoring the animal model after administration of I-131 trastuzumab The highest and lowest radiation-received organs were osteogenic cells (0.349 mSv/MBq) and skin (0.137 mSv/MBq), respectively. The mean coefficients of variation (%CV) of the effective dose equivalent and effective dose were 0.091 and 0.093 mSv/MBq respectively. We showed the feasibility of the pinholeattached conventional gamma camera for human use for the assessment of dosimetry. Mouse dosimetry and prediction of human dosimetry could be used to provide data for the safety and efficacy of newly developed therapeutic schemes.

Investigations of Au-198 as radiotracer in laboratory porous media using gamma camera: a preliminary study

NASA Astrophysics Data System (ADS)

Othman, N.; Kamal, W. H. B. Wan; Yusof, N. H.; Engku Chik, E. M. F.; Yunos, M. A. S.; Adnan, M. A. K.; Shari, M. R.

2018-01-01

Preliminary experiment has been carried out using irradiated Au-198 as radiotracer inside the laboratory porous media. The objectives are to check the compatibility of Au-198 as the radiotracer inside the porous media as well as to provide insights of fluid hydrodynamics inside the media using gamma camera.198Au is gamma emitter isotope with half-life of 2.7 days and energy of 0.41 MeV (99%). The porous media consists of fine sandstone with grain size 850μm, lubricant as the mimic of original oil in plant (OOIP) or trapped oil and a layer of cement on top of the rig as the bed rock. Gamma camera is arranged next to the porous media in order to capture the movement of radiotracer which has been set to 1minute per frame. Initially, the gold wire which has isotope of 197Au was irradiated inside the rotary rack of Reactor Triga PUSPATI (RTP) to produce 198Au. RTP is located in Nuclear Malaysia, Bangi has energy of 750kW and neutron flux of 5 × 102 n/cm2/s. 198Au, which is in liquid form, is injected inside the porous media and monitored and recorded by gamma camera. The gamma camera gives a quantitative determination of local fluid saturations over the area of observation.

Focal Plane Detectors for the Advanced Gamma-Ray Imaging System (AGIS)

NASA Astrophysics Data System (ADS)

Wagner, R. G.; Byrum, K.; Drake, G.; Funk, S.; Otte, N.; Smith, A.; Tajima, H.; Williams, D.

2009-05-01

The Advanced Gamma-Ray Imaging System (AGIS) is a concept for the next generation observatory in ground-based very high energy gamma-ray astronomy. It is being designed to achieve a significant improvement in sensitivity compared to current Imaging Air Cherenkov Telescope (IACT) Arrays. One of the main requirements in order that AGIS fulfills this goal will be to achieve higher angular resolution than current IACTs. Simulations show that a substantial improvement in angular resolution may be achieved if the pixel size is reduced to 0.05 deg, i.e. two to three times smaller than for current IACT cameras. Here we present results from testing of alternatives being considered for AGIS, including both silicon photomultipliers (SiPMs) and multi-anode photomultipliers (MAPMTs).

Generating Stereoscopic Television Images With One Camera

NASA Technical Reports Server (NTRS)

Coan, Paul P.

1996-01-01

Straightforward technique for generating stereoscopic television images involves use of single television camera translated laterally between left- and right-eye positions. Camera acquires one of images (left- or right-eye image), and video signal from image delayed while camera translated to position where it acquires other image. Length of delay chosen so both images displayed simultaneously or as nearly simultaneously as necessary to obtain stereoscopic effect. Technique amenable to zooming in on small areas within broad scenes. Potential applications include three-dimensional viewing of geological features and meteorological events from spacecraft and aircraft, inspection of workpieces moving along conveyor belts, and aiding ground and water search-and-rescue operations. Also used to generate and display imagery for public education and general information, and possible for medical purposes.

Simulation based evaluation of the designs of the Advanced Gamma-ray Imageing System (AGIS)

NASA Astrophysics Data System (ADS)

Bugaev, Slava; Buckley, James; Digel, Seth; Funk, Stephen; Konopelko, Alex; Krawczynski, Henric; Lebohec, Steohan; Maier, Gernot; Vassiliev, Vladimir

2009-05-01

The AGIS project under design study, is a large array of imaging atmospheric Cherenkov telescopes for gamma-rays astronomy between 40GeV and 100 TeV. In this paper we present the ongoing simulation effort to model the considered design approaches as a function of the main parameters such as array geometry, telescope optics and camera design in such a way the gamma ray observation capabilities can be optimized against the overall project cost.

Full image-processing pipeline in field-programmable gate array for a small endoscopic camera

NASA Astrophysics Data System (ADS)

Mostafa, Sheikh Shanawaz; Sousa, L. Natércia; Ferreira, Nuno Fábio; Sousa, Ricardo M.; Santos, Joao; Wäny, Martin; Morgado-Dias, F.

2017-01-01

Endoscopy is an imaging procedure used for diagnosis as well as for some surgical purposes. The camera used for the endoscopy should be small and able to produce a good quality image or video, to reduce discomfort of the patients, and to increase the efficiency of the medical team. To achieve these fundamental goals, a small endoscopy camera with a footprint of 1 mm×1 mm×1.65 mm is used. Due to the physical properties of the sensors and human vision system limitations, different image-processing algorithms, such as noise reduction, demosaicking, and gamma correction, among others, are needed to faithfully reproduce the image or video. A full image-processing pipeline is implemented using a field-programmable gate array (FPGA) to accomplish a high frame rate of 60 fps with minimum processing delay. Along with this, a viewer has also been developed to display and control the image-processing pipeline. The control and data transfer are done by a USB 3.0 end point in the computer. The full developed system achieves real-time processing of the image and fits in a Xilinx Spartan-6LX150 FPGA.

Digital camera with apparatus for authentication of images produced from an image file

NASA Technical Reports Server (NTRS)

Friedman, Gary L. (Inventor)

1993-01-01

A digital camera equipped with a processor for authentication of images produced from an image file taken by the digital camera is provided. The digital camera processor has embedded therein a private key unique to it, and the camera housing has a public key that is so uniquely based upon the private key that digital data encrypted with the private key by the processor may be decrypted using the public key. The digital camera processor comprises means for calculating a hash of the image file using a predetermined algorithm, and second means for encrypting the image hash with the private key, thereby producing a digital signature. The image file and the digital signature are stored in suitable recording means so they will be available together. Apparatus for authenticating at any time the image file as being free of any alteration uses the public key for decrypting the digital signature, thereby deriving a secure image hash identical to the image hash produced by the digital camera and used to produce the digital signature. The apparatus calculates from the image file an image hash using the same algorithm as before. By comparing this last image hash with the secure image hash, authenticity of the image file is determined if they match, since even one bit change in the image hash will cause the image hash to be totally different from the secure hash.

SU-F-J-200: An Improved Method for Event Selection in Compton Camera Imaging for Particle Therapy

DOE Office of Scientific and Technical Information (OSTI.GOV)

Mackin, D; Beddar, S; Polf, J

2016-06-15

Purpose: The uncertainty in the beam range in particle therapy limits the conformality of the dose distributions. Compton scatter cameras (CC), which measure the prompt gamma rays produced by nuclear interactions in the patient tissue, can reduce this uncertainty by producing 3D images confirming the particle beam range and dose delivery. However, the high intensity and short time windows of the particle beams limit the number of gammas detected. We attempt to address this problem by developing a method for filtering gamma ray scattering events from the background by applying the known gamma ray spectrum. Methods: We used a 4more » stage Compton camera to record in list mode the energy deposition and scatter positions of gammas from a Co-60 source. Each CC stage contained a 4×4 array of CdZnTe crystal. To produce images, we used a back-projection algorithm and four filtering Methods: basic, energy windowing, delta energy (ΔE), or delta scattering angle (Δθ). Basic filtering requires events to be physically consistent. Energy windowing requires event energy to fall within a defined range. ΔE filtering selects events with the minimum difference between the measured and a known gamma energy (1.17 and 1.33 MeV for Co-60). Δθ filtering selects events with the minimum difference between the measured scattering angle and the angle corresponding to a known gamma energy. Results: Energy window filtering reduced the FWHM from 197.8 mm for basic filtering to 78.3 mm. ΔE and Δθ filtering achieved the best results, FWHMs of 64.3 and 55.6 mm, respectively. In general, Δθ filtering selected events with scattering angles < 40°, while ΔE filtering selected events with angles > 60°. Conclusion: Filtering CC events improved the quality and resolution of the corresponding images. ΔE and Δθ filtering produced similar results but each favored different events.« less

Imaging characteristics of photogrammetric camera systems

USGS Publications Warehouse

Welch, R.; Halliday, J.

1973-01-01

In view of the current interest in high-altitude and space photographic systems for photogrammetric mapping, the United States Geological Survey (U.S.G.S.) undertook a comprehensive research project designed to explore the practical aspects of applying the latest image quality evaluation techniques to the analysis of such systems. The project had two direct objectives: (1) to evaluate the imaging characteristics of current U.S.G.S. photogrammetric camera systems; and (2) to develop methodologies for predicting the imaging capabilities of photogrammetric camera systems, comparing conventional systems with new or different types of systems, and analyzing the image quality of photographs. Image quality was judged in terms of a number of evaluation factors including response functions, resolving power, and the detectability and measurability of small detail. The limiting capabilities of the U.S.G.S. 6-inch and 12-inch focal length camera systems were established by analyzing laboratory and aerial photographs in terms of these evaluation factors. In the process, the contributing effects of relevant parameters such as lens aberrations, lens aperture, shutter function, image motion, film type, and target contrast procedures for analyzing image quality and predicting and comparing performance capabilities. ?? 1973.

Digital Camera with Apparatus for Authentication of Images Produced from an Image File

NASA Technical Reports Server (NTRS)

Friedman, Gary L. (Inventor)

1996-01-01

A digital camera equipped with a processor for authentication of images produced from an image file taken by the digital camera is provided. The digital camera processor has embedded therein a private key unique to it, and the camera housing has a public key that is so uniquely related to the private key that digital data encrypted with the private key may be decrypted using the public key. The digital camera processor comprises means for calculating a hash of the image file using a predetermined algorithm, and second means for encrypting the image hash with the private key, thereby producing a digital signature. The image file and the digital signature are stored in suitable recording means so they will be available together. Apparatus for authenticating the image file as being free of any alteration uses the public key for decrypting the digital signature, thereby deriving a secure image hash identical to the image hash produced by the digital camera and used to produce the digital signature. The authenticating apparatus calculates from the image file an image hash using the same algorithm as before. By comparing this last image hash with the secure image hash, authenticity of the image file is determined if they match. Other techniques to address time-honored methods of deception, such as attaching false captions or inducing forced perspectives, are included.

Methods for identification of images acquired with digital cameras

NASA Astrophysics Data System (ADS)

Geradts, Zeno J.; Bijhold, Jurrien; Kieft, Martijn; Kurosawa, Kenji; Kuroki, Kenro; Saitoh, Naoki

2001-02-01

From the court we were asked whether it is possible to determine if an image has been made with a specific digital camera. This question has to be answered in child pornography cases, where evidence is needed that a certain picture has been made with a specific camera. We have looked into different methods of examining the cameras to determine if a specific image has been made with a camera: defects in CCDs, file formats that are used, noise introduced by the pixel arrays and watermarking in images used by the camera manufacturer.

Multimodal US-gamma imaging using collaborative robotics for cancer staging biopsies.

PubMed

Esposito, Marco; Busam, Benjamin; Hennersperger, Christoph; Rackerseder, Julia; Navab, Nassir; Frisch, Benjamin

2016-09-01

The staging of female breast cancer requires detailed information about the level of cancer spread through the lymphatic system. Common practice to obtain this information for patients with early-stage cancer is sentinel lymph node (SLN) biopsy, where LNs are radioactively identified for surgical removal and subsequent histological analysis. Punch needle biopsy is a less invasive approach but suffers from the lack of combined anatomical and nuclear information. We present and evaluate a system that introduces live collaborative robotic 2D gamma imaging in addition to live 2D ultrasound to identify SLNs in the surrounding anatomy. The system consists of a robotic arm equipped with both a gamma camera and a stereoscopic tracking system that monitors the position of an ultrasound probe operated by the physician. The arm cooperatively places the gamma camera parallel to the ultrasound imaging plane to provide live multimodal visualization and guidance. We validate the system by evaluating the target registration errors between fused nuclear and US image data in a phantom consisting of two spheres, one of which is filled with radioactivity. Medical experts perform punch biopsies on agar-gelatine phantoms with complex configurations of hot and cold lesions to provide a qualitative and quantitative evaluation of the system. The average point registration error for the overlay is [Formula: see text] mm. The time of the entire procedure was reduced by 36 %, with 80v of the biopsies being successful. The users' feedback was very positive, and the system was deemed to be very intuitive, with handling similar to classic US-guided needle biopsy. We present and evaluate the first medical collaborative robotic imaging system. Feedback from potential users for SLN punch needle biopsy is encouraging. Ongoing work investigates the clinical feasibility with more complex and realistic phantoms.

Engineering design criteria for an image intensifier/image converter camera

NASA Technical Reports Server (NTRS)

Sharpsteen, J. T.; Lund, D. L.; Stoap, L. J.; Solheim, C. D.

1976-01-01

The design, display, and evaluation of an image intensifier/image converter camera which can be utilized in various requirements of spaceshuttle experiments are described. An image intensifier tube was utilized in combination with two brassboards as power supply and used for evaluation of night photography in the field. Pictures were obtained showing field details which would have been undistinguishable to the naked eye or to an ordinary camera.

Low Statistics Reconstruction of the Compton Camera Point Spread Function in 3D Prompt-γ Imaging of Ion Beam Therapy

NASA Astrophysics Data System (ADS)

Lojacono, Xavier; Richard, Marie-Hélène; Ley, Jean-Luc; Testa, Etienne; Ray, Cédric; Freud, Nicolas; Létang, Jean Michel; Dauvergne, Denis; Maxim, Voichiţa; Prost, Rémy

2013-10-01

The Compton camera is a relevant imaging device for the detection of prompt photons produced by nuclear fragmentation in hadrontherapy. It may allow an improvement in detection efficiency compared to a standard gamma-camera but requires more sophisticated image reconstruction techniques. In this work, we simulate low statistics acquisitions from a point source having a broad energy spectrum compatible with hadrontherapy. We then reconstruct the image of the source with a recently developed filtered backprojection algorithm, a line-cone approach and an iterative List Mode Maximum Likelihood Expectation Maximization algorithm. Simulated data come from a Compton camera prototype designed for hadrontherapy online monitoring. Results indicate that the achievable resolution in directions parallel to the detector, that may include the beam direction, is compatible with the quality control requirements. With the prototype under study, the reconstructed image is elongated in the direction orthogonal to the detector. However this direction is of less interest in hadrontherapy where the first requirement is to determine the penetration depth of the beam in the patient. Additionally, the resolution may be recovered using a second camera.

Material efficiency studies for a Compton camera designed to measure characteristic prompt gamma rays emitted during proton beam radiotherapy

PubMed Central

Robertson, Daniel; Polf, Jerimy C; Peterson, Steve W; Gillin, Michael T; Beddar, Sam

2011-01-01

Prompt gamma rays emitted from biological tissues during proton irradiation carry dosimetric and spectroscopic information that can assist with treatment verification and provide an indication of the biological response of the irradiated tissues. Compton cameras are capable of determining the origin and energy of gamma rays. However, prompt gamma monitoring during proton therapy requires new Compton camera designs that perform well at the high gamma energies produced when tissues are bombarded with therapeutic protons. In this study we optimize the materials and geometry of a three-stage Compton camera for prompt gamma detection and calculate the theoretical efficiency of such a detector. The materials evaluated in this study include germanium, bismuth germanate (BGO), NaI, xenon, silicon and lanthanum bromide (LaBr3). For each material, the dimensions of each detector stage were optimized to produce the maximum number of relevant interactions. These results were used to predict the efficiency of various multi-material cameras. The theoretical detection efficiencies of the most promising multi-material cameras were then calculated for the photons emitted from a tissue-equivalent phantom irradiated by therapeutic proton beams ranging from 50 to 250 MeV. The optimized detector stages had a lateral extent of 10 × 10 cm2 with the thickness of the initial two stages dependent on the detector material. The thickness of the third stage was fixed at 10 cm regardless of material. The most efficient single-material cameras were composed of germanium (3 cm) and BGO (2.5 cm). These cameras exhibited efficiencies of 1.15 × 10−4 and 9.58 × 10−5 per incident proton, respectively. The most efficient multi-material camera design consisted of two initial stages of germanium (3 cm) and a final stage of BGO, resulting in a theoretical efficiency of 1.26 × 10−4 per incident proton. PMID:21508442

Image Alignment for Multiple Camera High Dynamic Range Microscopy.

PubMed

Eastwood, Brian S; Childs, Elisabeth C

2012-01-09

This paper investigates the problem of image alignment for multiple camera high dynamic range (HDR) imaging. HDR imaging combines information from images taken with different exposure settings. Combining information from multiple cameras requires an alignment process that is robust to the intensity differences in the images. HDR applications that use a limited number of component images require an alignment technique that is robust to large exposure differences. We evaluate the suitability for HDR alignment of three exposure-robust techniques. We conclude that image alignment based on matching feature descriptors extracted from radiant power images from calibrated cameras yields the most accurate and robust solution. We demonstrate the use of this alignment technique in a high dynamic range video microscope that enables live specimen imaging with a greater level of detail than can be captured with a single camera.

Image Alignment for Multiple Camera High Dynamic Range Microscopy

PubMed Central

Eastwood, Brian S.; Childs, Elisabeth C.

2012-01-01

This paper investigates the problem of image alignment for multiple camera high dynamic range (HDR) imaging. HDR imaging combines information from images taken with different exposure settings. Combining information from multiple cameras requires an alignment process that is robust to the intensity differences in the images. HDR applications that use a limited number of component images require an alignment technique that is robust to large exposure differences. We evaluate the suitability for HDR alignment of three exposure-robust techniques. We conclude that image alignment based on matching feature descriptors extracted from radiant power images from calibrated cameras yields the most accurate and robust solution. We demonstrate the use of this alignment technique in a high dynamic range video microscope that enables live specimen imaging with a greater level of detail than can be captured with a single camera. PMID:22545028

Multispectral image dissector camera flight test

NASA Technical Reports Server (NTRS)

Johnson, B. L.

1973-01-01

It was demonstrated that the multispectral image dissector camera is able to provide composite pictures of the earth surface from high altitude overflights. An electronic deflection feature was used to inject the gyro error signal into the camera for correction of aircraft motion.

Development of an intraoperative gamma camera based on a 256-pixel mercuric iodide detector array

NASA Astrophysics Data System (ADS)

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

1997-06-01

A 256-element mercuric iodide (HgI/sub 2/) detector array has been developed which is intended for use as an intraoperative gamma camera (IOGC). The camera is specifically designed for use in imaging gamma-emitting radiopharmaceuticals (such as 99m-Tc labeled Sestamibi) incorporated into brain tumors in the intraoperative surgical environment. The system is intended to improve the success of tumor removal surgeries by allowing more complete removal of subclinical tumor cells without removal of excessive normal tissue. The use of HgI/sub 2/ detector arrays in this application facilitates construction of an imaging head that is very compact and has a high SNR. The detector is configured as a cross-grid array. Pixel dimensions are 1.25 mm squares separated by 0.25 mm. The overall dimension of the detector is 23.75 mm on a side. The detector thickness is 1 mm which corresponds to over 60% stopping at 140 keV. The array has good uniformity with average energy resolution of 5.2/spl plusmn/2.9% FWHM at 140 keV (best resolution was 1.9% FWHM). Response uniformity (/spl plusmn//spl sigma/) was 7.9%. A study utilizing realistic tumor phantoms (uptake ratio varied from 2:1 to 100:1) in background (1 mCi/l) was conducted. SNRs for the reasonably achievable uptake ratio of 50:1 were 5.61 /spl sigma/ with 1 cm of background depth ("normal tissue") and 2.74 /spl sigma/ with 4 cm of background for a 6.3 /spl mu/l tumor phantom (/spl sim/270 nCi at the time of the measurement).

Improvement of passive THz camera images

NASA Astrophysics Data System (ADS)

Kowalski, Marcin; Piszczek, Marek; Palka, Norbert; Szustakowski, Mieczyslaw

2012-10-01

Terahertz technology is one of emerging technologies that has a potential to change our life. There are a lot of attractive applications in fields like security, astronomy, biology and medicine. Until recent years, terahertz (THz) waves were an undiscovered, or most importantly, an unexploited area of electromagnetic spectrum. The reasons of this fact were difficulties in generation and detection of THz waves. Recent advances in hardware technology have started to open up the field to new applications such as THz imaging. The THz waves can penetrate through various materials. However, automated processing of THz images can be challenging. The THz frequency band is specially suited for clothes penetration because this radiation does not point any harmful ionizing effects thus it is safe for human beings. Strong technology development in this band have sparked with few interesting devices. Even if the development of THz cameras is an emerging topic, commercially available passive cameras still offer images of poor quality mainly because of its low resolution and low detectors sensitivity. Therefore, THz image processing is very challenging and urgent topic. Digital THz image processing is a really promising and cost-effective way for demanding security and defense applications. In the article we demonstrate the results of image quality enhancement and image fusion of images captured by a commercially available passive THz camera by means of various combined methods. Our research is focused on dangerous objects detection - guns, knives and bombs hidden under some popular types of clothing.

Focal Plane Detectors for the Advanced Gamma-Ray Imaging System (AGIS)

NASA Astrophysics Data System (ADS)

Otte, A. N.; Byrum, K.; Drake, G.; Falcone, A.; Funk, S.; Horan, D.; Mukherjee, R.; Smith, A.; Tajima, H.; Wagner, R. G.; Williams, D. A.

2008-12-01

The Advanced Gamma-Ray Imaging System (AGIS) is a concept for the next generation observatory in ground-based very high energy gamma-ray astronomy. Design goals are ten times better sensitivity, higher angular resolution, and a lower energy threshold than existing Cherenkov telescopes. Simulations show that a substantial improvement in angular resolution may be achieved if the pixel diameter is reduced to the order of 0.05 deg, i.e. two to three times smaller than the pixel diameter of current Cherenkov telescope cameras. At these dimensions, photon detectors with smaller physical dimensions can be attractive alternatives to the classical photomultiplier tube (PMT). Furthermore, the operation of an experiment with the size of AGIS requires photon detectors that are among other things more reliable, more durable, and possibly higher efficiency photon detectors. Alternative photon detectors we are considering for AGIS include both silicon photomultipliers (SiPMs) and multi-anode photomultipliers (MAPMTs). Here we present results from laboratory testing of MAPMTs and SiPMs along with results from the first incorporation of these devices into cameras on test bed Cherenkov telescopes.

A high-speed digital camera system for the observation of rapid H-alpha fluctuations in solar flares

NASA Technical Reports Server (NTRS)

Kiplinger, Alan L.; Dennis, Brian R.; Orwig, Larry E.

1989-01-01

Researchers developed a prototype digital camera system for obtaining H-alpha images of solar flares with 0.1 s time resolution. They intend to operate this system in conjunction with SMM's Hard X Ray Burst Spectrometer, with x ray instruments which will be available on the Gamma Ray Observatory and eventually with the Gamma Ray Imaging Device (GRID), and with the High Resolution Gamma-Ray and Hard X Ray Spectrometer (HIREGS) which are being developed for the Max '91 program. The digital camera has recently proven to be successful as a one camera system operating in the blue wing of H-alpha during the first Max '91 campaign. Construction and procurement of a second and possibly a third camera for simultaneous observations at other wavelengths are underway as are analyses of the campaign data.

A machine learning method for fast and accurate characterization of depth-of-interaction gamma cameras

NASA Astrophysics Data System (ADS)

Pedemonte, Stefano; Pierce, Larry; Van Leemput, Koen

2017-11-01

Measuring the depth-of-interaction (DOI) of gamma photons enables increasing the resolution of emission imaging systems. Several design variants of DOI-sensitive detectors have been recently introduced to improve the performance of scanners for positron emission tomography (PET). However, the accurate characterization of the response of DOI detectors, necessary to accurately measure the DOI, remains an unsolved problem. Numerical simulations are, at the state of the art, imprecise, while measuring directly the characteristics of DOI detectors experimentally is hindered by the impossibility to impose the depth-of-interaction in an experimental set-up. In this article we introduce a machine learning approach for extracting accurate forward models of gamma imaging devices from simple pencil-beam measurements, using a nonlinear dimensionality reduction technique in combination with a finite mixture model. The method is purely data-driven, not requiring simulations, and is applicable to a wide range of detector types. The proposed method was evaluated both in a simulation study and with data acquired using a monolithic gamma camera designed for PET (the cMiCE detector), demonstrating the accurate recovery of the DOI characteristics. The combination of the proposed calibration technique with maximum- a posteriori estimation of the coordinates of interaction provided a depth resolution of  ≈1.14 mm for the simulated PET detector and  ≈1.74 mm for the cMiCE detector. The software and experimental data are made available at http://occiput.mgh.harvard.edu/depthembedding/.

Optimal configuration of a low-dose breast-specific gamma camera based on semiconductor CdZnTe pixelated detectors

NASA Astrophysics Data System (ADS)

Genocchi, B.; Pickford Scienti, O.; Darambara, DG

2017-05-01

Breast cancer is one of the most frequent tumours in women. During the ‘90s, the introduction of screening programmes allowed the detection of cancer before the palpable stage, reducing its mortality up to 50%. About 50% of the women aged between 30 and 50 years present dense breast parenchyma. This percentage decreases to 30% for women between 50 to 80 years. In these women, mammography has a sensitivity of around 30%, and small tumours are covered by the dense parenchyma and missed in the mammogram. Interestingly, breast-specific gamma-cameras based on semiconductor CdZnTe detectors have shown to be of great interest to early diagnosis. Infact, due to the high energy, spatial resolution, and high sensitivity of CdZnTe, molecular breast imaging has been shown to have a sensitivity of about 90% independently of the breast parenchyma. The aim of this work is to determine the optimal combination of the detector pixel size, hole shape, and collimator material in a low dose dual head breast specific gamma camera based on a CdZnTe pixelated detector at 140 keV, in order to achieve high count rate, and the best possible image spatial resolution. The optimal combination has been studied by modeling the system using the Monte Carlo code GATE. Six different pixel sizes from 0.85 mm to 1.6 mm, two hole shapes, hexagonal and square, and two different collimator materials, lead and tungsten were considered. It was demonstrated that the camera achieved higher count rates, and better signal-to-noise ratio when equipped with square hole, and large pixels (> 1.3 mm). In these configurations, the spatial resolution was worse than using small pixel sizes (< 1.3 mm), but remained under 3.6 mm in all cases.

Prediction of Viking lander camera image quality

NASA Technical Reports Server (NTRS)

Huck, F. O.; Burcher, E. E.; Jobson, D. J.; Wall, S. D.

1976-01-01

Formulations are presented that permit prediction of image quality as a function of camera performance, surface radiance properties, and lighting and viewing geometry. Predictions made for a wide range of surface radiance properties reveal that image quality depends strongly on proper camera dynamic range command and on favorable lighting and viewing geometry. Proper camera dynamic range commands depend mostly on the surface albedo that will be encountered. Favorable lighting and viewing geometries depend mostly on lander orientation with respect to the diurnal sun path over the landing site, and tend to be independent of surface albedo and illumination scattering function. Side lighting with low sun elevation angles (10 to 30 deg) is generally favorable for imaging spatial details and slopes, whereas high sun elevation angles are favorable for measuring spectral reflectances.

Capturing method for integral three-dimensional imaging using multiviewpoint robotic cameras

NASA Astrophysics Data System (ADS)

Ikeya, Kensuke; Arai, Jun; Mishina, Tomoyuki; Yamaguchi, Masahiro

2018-03-01

Integral three-dimensional (3-D) technology for next-generation 3-D television must be able to capture dynamic moving subjects with pan, tilt, and zoom camerawork as good as in current TV program production. We propose a capturing method for integral 3-D imaging using multiviewpoint robotic cameras. The cameras are controlled through a cooperative synchronous system composed of a master camera controlled by a camera operator and other reference cameras that are utilized for 3-D reconstruction. When the operator captures a subject using the master camera, the region reproduced by the integral 3-D display is regulated in real space according to the subject's position and view angle of the master camera. Using the cooperative control function, the reference cameras can capture images at the narrowest view angle that does not lose any part of the object region, thereby maximizing the resolution of the image. 3-D models are reconstructed by estimating the depth from complementary multiviewpoint images captured by robotic cameras arranged in a two-dimensional array. The model is converted into elemental images to generate the integral 3-D images. In experiments, we reconstructed integral 3-D images of karate players and confirmed that the proposed method satisfied the above requirements.

Gamma-Ray Imaging Probes.

NASA Astrophysics Data System (ADS)

Wild, Walter James

1988-12-01

External nuclear medicine diagnostic imaging of early primary and metastatic lung cancer tumors is difficult due to the poor sensitivity and resolution of existing gamma cameras. Nonimaging counting detectors used for internal tumor detection give ambiguous results because distant background variations are difficult to discriminate from neighboring tumor sites. This suggests that an internal imaging nuclear medicine probe, particularly an esophageal probe, may be advantageously used to detect small tumors because of the ability to discriminate against background variations and the capability to get close to sites neighboring the esophagus. The design, theory of operation, preliminary bench tests, characterization of noise behavior and optimization of such an imaging probe is the central theme of this work. The central concept lies in the representation of the aperture shell by a sequence of binary digits. This, coupled with the mode of operation which is data encoding within an axial slice of space, leads to the fundamental imaging equation in which the coding operation is conveniently described by a circulant matrix operator. The coding/decoding process is a classic coded-aperture problem, and various estimators to achieve decoding are discussed. Some estimators require a priori information about the object (or object class) being imaged; the only unbiased estimator that does not impose this requirement is the simple inverse-matrix operator. The effects of noise on the estimate (or reconstruction) is discussed for general noise models and various codes/decoding operators. The choice of an optimal aperture for detector count times of clinical relevance is examined using a statistical class-separability formalism.

Volumetric particle image velocimetry with a single plenoptic camera

NASA Astrophysics Data System (ADS)

Fahringer, Timothy W.; Lynch, Kyle P.; Thurow, Brian S.

2015-11-01

A novel three-dimensional (3D), three-component (3C) particle image velocimetry (PIV) technique based on volume illumination and light field imaging with a single plenoptic camera is described. A plenoptic camera uses a densely packed microlens array mounted near a high resolution image sensor to sample the spatial and angular distribution of light collected by the camera. The multiplicative algebraic reconstruction technique (MART) computed tomography algorithm is used to reconstruct a volumetric intensity field from individual snapshots and a cross-correlation algorithm is used to estimate the velocity field from a pair of reconstructed particle volumes. This work provides an introduction to the basic concepts of light field imaging with a plenoptic camera and describes the unique implementation of MART in the context of plenoptic image data for 3D/3C PIV measurements. Simulations of a plenoptic camera using geometric optics are used to generate synthetic plenoptic particle images, which are subsequently used to estimate the quality of particle volume reconstructions at various particle number densities. 3D reconstructions using this method produce reconstructed particles that are elongated by a factor of approximately 4 along the optical axis of the camera. A simulated 3D Gaussian vortex is used to test the capability of single camera plenoptic PIV to produce a 3D/3C vector field, where it was found that lateral displacements could be measured to approximately 0.2 voxel accuracy in the lateral direction and 1 voxel in the depth direction over a 300× 200× 200 voxel volume. The feasibility of the technique is demonstrated experimentally using a home-built plenoptic camera based on a 16-megapixel interline CCD camera and a 289× 193 array of microlenses and a pulsed Nd:YAG laser. 3D/3C measurements were performed in the wake of a low Reynolds number circular cylinder and compared with measurements made using a conventional 2D/2C PIV system. Overall, single camera

Evaluation of a gamma camera system for the RITS-6 accelerator using the self-magnetic pinch diode

NASA Astrophysics Data System (ADS)

Webb, Timothy J.; Kiefer, Mark L.; Gignac, Raymond; Baker, Stuart A.

2015-08-01

The self-magnetic pinch (SMP) diode is an intense radiographic source fielded on the Radiographic Integrated Test Stand (RITS-6) accelerator at Sandia National Laboratories in Albuquerque, NM. The accelerator is an inductive voltage adder (IVA) that can operate from 2-10 MV with currents up to 160 kA (at 7 MV). The SMP diode consists of an annular cathode separated from a flat anode, holding the bremsstrahlung conversion target, by a vacuum gap. Until recently the primary imaging diagnostic utilized image plates (storage phosphors) which has generally low DQE at these photon energies along with other problems. The benefits of using image plates include a high-dynamic range, good spatial resolution, and ease of use. A scintillator-based X-ray imaging system or "gamma camera" has been fielded in front of RITS and the SMP diode which has been able to provide vastly superior images in terms of signal-to-noise with similar resolution and acceptable dynamic range.

Nuclear Radiation Degradation Study on HD Camera Based on CMOS Image Sensor at Different Dose Rates.

PubMed

Wang, Congzheng; Hu, Song; Gao, Chunming; Feng, Chang

2018-02-08

In this work, we irradiated a high-definition (HD) industrial camera based on a commercial-off-the-shelf (COTS) CMOS image sensor (CIS) with Cobalt-60 gamma-rays. All components of the camera under test were fabricated without radiation hardening, except for the lens. The irradiation experiments of the HD camera under biased conditions were carried out at 1.0, 10.0, 20.0, 50.0 and 100.0 Gy/h. During the experiment, we found that the tested camera showed a remarkable degradation after irradiation and differed in the dose rates. With the increase of dose rate, the same target images become brighter. Under the same dose rate, the radiation effect in bright area is lower than that in dark area. Under different dose rates, the higher the dose rate is, the worse the radiation effect will be in both bright and dark areas. And the standard deviations of bright and dark areas become greater. Furthermore, through the progressive degradation analysis of the captured image, experimental results demonstrate that the attenuation of signal to noise ratio (SNR) versus radiation time is not obvious at the same dose rate, and the degradation is more and more serious with increasing dose rate. Additionally, the decrease rate of SNR at 20.0, 50.0 and 100.0 Gy/h is far greater than that at 1.0 and 10.0 Gy/h. Even so, we confirm that the HD industrial camera is still working at 10.0 Gy/h during the 8 h of measurements, with a moderate decrease of the SNR (5 dB). The work is valuable and can provide suggestion for camera users in the radiation field.

Performance of the prototype LaBr3 spectrometer developed for the JET gamma-ray camera upgrade.

PubMed

Rigamonti, D; Muraro, A; Nocente, M; Perseo, V; Boltruczyk, G; Fernandes, A; Figueiredo, J; Giacomelli, L; Gorini, G; Gosk, M; Kiptily, V; Korolczuk, S; Mianowski, S; Murari, A; Pereira, R C; Cippo, E P; Zychor, I; Tardocchi, M

2016-11-01

In this work, we describe the solution developed by the gamma ray camera upgrade enhancement project to improve the spectroscopic properties of the existing JET γ-ray camera. Aim of the project is to enable gamma-ray spectroscopy in JET deuterium-tritium plasmas. A dedicated pilot spectrometer based on a LaBr 3 crystal coupled to a silicon photo-multiplier has been developed. A proper pole zero cancellation network able to shorten the output signal to a length of 120 ns has been implemented allowing for spectroscopy at MHz count rates. The system has been characterized in the laboratory and shows an energy resolution of 5.5% at E γ = 0.662 MeV, which extrapolates favorably in the energy range of interest for gamma-ray emission from fast ions in fusion plasmas.

Effect of different thickness of material filter on Tc-99m spectra and performance parameters of gamma camera

NASA Astrophysics Data System (ADS)

Nazifah, A.; Norhanna, S.; Shah, S. I.; Zakaria, A.

2014-11-01

This study aimed to investigate the effects of material filter technique on Tc-99m spectra and performance parameters of Philip ADAC forte dual head gamma camera. Thickness of material filter was selected on the basis of percentage attenuation of various gamma ray energies by different thicknesses of zinc material. A cylindrical source tank of NEMA single photon emission computed tomography (SPECT) Triple Line Source Phantom filled with water and Tc-99m radionuclide injected was used for spectra, uniformity and sensitivity measurements. Vinyl plastic tube was used as a line source for spatial resolution. Images for uniformity were reconstructed by filtered back projection method. Butterworth filter of order 5 and cut off frequency 0.35 cycles/cm was selected. Chang's attenuation correction method was applied by selecting 0.13/cm linear attenuation coefficient. Count rate was decreased with material filter from the compton region of Tc-99m energy spectrum, also from the photopeak region. Spatial resolution was improved. However, uniformity of tomographic image was equivocal, and system volume sensitivity was reduced by material filter. Material filter improved system's spatial resolution. Therefore, the technique may be used for phantom studies to improve the image quality.

a Spatio-Spectral Camera for High Resolution Hyperspectral Imaging

NASA Astrophysics Data System (ADS)

Livens, S.; Pauly, K.; Baeck, P.; Blommaert, J.; Nuyts, D.; Zender, J.; Delauré, B.

2017-08-01

Imaging with a conventional frame camera from a moving remotely piloted aircraft system (RPAS) is by design very inefficient. Less than 1 % of the flying time is used for collecting light. This unused potential can be utilized by an innovative imaging concept, the spatio-spectral camera. The core of the camera is a frame sensor with a large number of hyperspectral filters arranged on the sensor in stepwise lines. It combines the advantages of frame cameras with those of pushbroom cameras. By acquiring images in rapid succession, such a camera can collect detailed hyperspectral information, while retaining the high spatial resolution offered by the sensor. We have developed two versions of a spatio-spectral camera and used them in a variety of conditions. In this paper, we present a summary of three missions with the in-house developed COSI prototype camera (600-900 nm) in the domains of precision agriculture (fungus infection monitoring in experimental wheat plots), horticulture (crop status monitoring to evaluate irrigation management in strawberry fields) and geology (meteorite detection on a grassland field). Additionally, we describe the characteristics of the 2nd generation, commercially available ButterflEYE camera offering extended spectral range (475-925 nm), and we discuss future work.

An image-tube camera for cometary spectrography

NASA Astrophysics Data System (ADS)

Mamadov, O.

The paper discusses the mounting of an image tube camera. The cathode is of antimony, sodium, potassium, and cesium. The parts used for mounting are of acrylic plastic and a fabric-based laminate. A mounting design that does not include cooling is presented. The aperture ratio of the camera is 1:27. Also discussed is the way that the camera is joined to the spectrograph.

High dynamic range image acquisition based on multiplex cameras

NASA Astrophysics Data System (ADS)

Zeng, Hairui; Sun, Huayan; Zhang, Tinghua

2018-03-01

High dynamic image is an important technology of photoelectric information acquisition, providing higher dynamic range and more image details, and it can better reflect the real environment, light and color information. Currently, the method of high dynamic range image synthesis based on different exposure image sequences cannot adapt to the dynamic scene. It fails to overcome the effects of moving targets, resulting in the phenomenon of ghost. Therefore, a new high dynamic range image acquisition method based on multiplex cameras system was proposed. Firstly, different exposure images sequences were captured with the camera array, using the method of derivative optical flow based on color gradient to get the deviation between images, and aligned the images. Then, the high dynamic range image fusion weighting function was established by combination of inverse camera response function and deviation between images, and was applied to generated a high dynamic range image. The experiments show that the proposed method can effectively obtain high dynamic images in dynamic scene, and achieves good results.

High-frame rate multiport CCD imager and camera

NASA Astrophysics Data System (ADS)

Levine, Peter A.; Patterson, David R.; Esposito, Benjamin J.; Tower, John R.; Lawler, William B.

1993-01-01

A high frame rate visible CCD camera capable of operation up to 200 frames per second is described. The camera produces a 256 X 256 pixel image by using one quadrant of a 512 X 512 16-port, back illuminated CCD imager. Four contiguous outputs are digitally reformatted into a correct, 256 X 256 image. This paper details the architecture and timing used for the CCD drive circuits, analog processing, and the digital reformatter.

Modulated electron-multiplied fluorescence lifetime imaging microscope: all-solid-state camera for fluorescence lifetime imaging.

PubMed

Zhao, Qiaole; Schelen, Ben; Schouten, Raymond; van den Oever, Rein; Leenen, René; van Kuijk, Harry; Peters, Inge; Polderdijk, Frank; Bosiers, Jan; Raspe, Marcel; Jalink, Kees; Geert Sander de Jong, Jan; van Geest, Bert; Stoop, Karel; Young, Ian Ted

2012-12-01

We have built an all-solid-state camera that is directly modulated at the pixel level for frequency-domain fluorescence lifetime imaging microscopy (FLIM) measurements. This novel camera eliminates the need for an image intensifier through the use of an application-specific charge coupled device design in a frequency-domain FLIM system. The first stage of evaluation for the camera has been carried out. Camera characteristics such as noise distribution, dark current influence, camera gain, sampling density, sensitivity, linearity of photometric response, and optical transfer function have been studied through experiments. We are able to do lifetime measurement using our modulated, electron-multiplied fluorescence lifetime imaging microscope (MEM-FLIM) camera for various objects, e.g., fluorescein solution, fixed green fluorescent protein (GFP) cells, and GFP-actin stained live cells. A detailed comparison of a conventional microchannel plate (MCP)-based FLIM system and the MEM-FLIM system is presented. The MEM-FLIM camera shows higher resolution and a better image quality. The MEM-FLIM camera provides a new opportunity for performing frequency-domain FLIM.

The imaging system design of three-line LMCCD mapping camera

NASA Astrophysics Data System (ADS)

Zhou, Huai-de; Liu, Jin-Guo; Wu, Xing-Xing; Lv, Shi-Liang; Zhao, Ying; Yu, Da

2011-08-01

In this paper, the authors introduced the theory about LMCCD (line-matrix CCD) mapping camera firstly. On top of the introduction were consists of the imaging system of LMCCD mapping camera. Secondly, some pivotal designs which were Introduced about the imaging system, such as the design of focal plane module, the video signal's procession, the controller's design of the imaging system, synchronous photography about forward and nadir and backward camera and the nadir camera of line-matrix CCD. At last, the test results of LMCCD mapping camera imaging system were introduced. The results as following: the precision of synchronous photography about forward and nadir and backward camera is better than 4 ns and the nadir camera of line-matrix CCD is better than 4 ns too; the photography interval of line-matrix CCD of the nadir camera can satisfy the butter requirements of LMCCD focal plane module; the SNR tested in laboratory is better than 95 under typical working condition(the solar incidence degree is 30, the reflectivity of the earth's surface is 0.3) of each CCD image; the temperature of the focal plane module is controlled under 30° in a working period of 15 minutes. All of these results can satisfy the requirements about the synchronous photography, the temperature control of focal plane module and SNR, Which give the guarantee of precision for satellite photogrammetry.

Super-resolved all-refocused image with a plenoptic camera

NASA Astrophysics Data System (ADS)

Wang, Xiang; Li, Lin; Hou, Guangqi

2015-12-01

This paper proposes an approach to produce the super-resolution all-refocused images with the plenoptic camera. The plenoptic camera can be produced by putting a micro-lens array between the lens and the sensor in a conventional camera. This kind of camera captures both the angular and spatial information of the scene in one single shot. A sequence of digital refocused images, which are refocused at different depth, can be produced after processing the 4D light field captured by the plenoptic camera. The number of the pixels in the refocused image is the same as that of the micro-lens in the micro-lens array. Limited number of the micro-lens will result in poor low resolution refocused images. Therefore, not enough details will exist in these images. Such lost details, which are often high frequency information, are important for the in-focus part in the refocused image. We decide to super-resolve these in-focus parts. The result of image segmentation method based on random walks, which works on the depth map produced from the 4D light field data, is used to separate the foreground and background in the refocused image. And focusing evaluation function is employed to determine which refocused image owns the clearest foreground part and which one owns the clearest background part. Subsequently, we employ single image super-resolution method based on sparse signal representation to process the focusing parts in these selected refocused images. Eventually, we can obtain the super-resolved all-focus image through merging the focusing background part and the focusing foreground part in the way of digital signal processing. And more spatial details will be kept in these output images. Our method will enhance the resolution of the refocused image, and just the refocused images owning the clearest foreground and background need to be super-resolved.

Application of Two Phase (Liquid/Gas) Xenon Gamma-Camera for the Detection of Special Nuclear Material and PET Medical Imaging

DOE Office of Scientific and Technical Information (OSTI.GOV)

McKinsey, Daniel Nicholas

The McKinsey group at Yale has been awarded a grant from DTRA for the building of a Liquid Xenon Gamma Ray Color Camera (LXe-GRCC), which combines state-of-the-art detection of LXe scintillation light and time projection chamber (TPC) charge readout. The DTRA application requires a movable detector and hence only a single phase (liquid) xenon detector can be considered in this case. We propose to extend the DTRA project to applications that allow a two phase (liquid/gas) xenon TPC. This entails additional (yet minimal) hardware and extension of the research effort funded by DTRA. The two phase detector will have bettermore » energy and angular resolution. Such detectors will be useful for PET medical imaging and detection of special nuclear material in stationary applications (e.g. port of entry). The expertise of the UConn group in gas phase TPCs will enhance the capabilities of the Yale group and the synergy between the two groups will be very beneficial for this research project as well as the education and research projects of the two universities. The LXe technology to be used in this project has matured rapidly over the past few years, developed for use in detectors for nuclear physics and astrophysics. This technology may now be applied in a straightforward way to the imaging of gamma rays. According to detailed Monte Carlo simulations recently performed at Yale University, energy resolution of 1% and angular resolution of 3 degrees may be obtained for 1.0 MeV gamma rays, using existing technology. With further research and development, energy resolution of 0.5% and angular resolution of 1.3 degrees will be possible at 1.0 MeV. Because liquid xenon is a high density, high Z material, it is highly efficient for scattering and capturing gamma rays. In addition, this technology scales elegantly to large detector areas, with several square meter apertures possible. The Yale research group is highly experienced in the development and use of noble liquid

Multiple-image oscilloscope camera

DOEpatents

Yasillo, Nicholas J.

1978-01-01

An optical device for placing automatically a plurality of images at selected locations on one film comprises a stepping motor coupled to a rotating mirror and lens. A mechanical connection from the mirror controls an electronic logical system to allow rotation of the mirror to place a focused image at the desired preselected location. The device is of especial utility when used to place four images on a single film to record oscilloscope views obtained in gamma radiography.

High-Resolution Mars Camera Test Image of Moon Infrared

NASA Image and Video Library

2005-09-13

This crescent view of Earth Moon in infrared wavelengths comes from a camera test by NASA Mars Reconnaissance Orbiter spacecraft on its way to Mars. This image was taken by taken by the High Resolution Imaging Science Experiment camera Sept. 8, 2005.

Earth elevation map production and high resolution sensing camera imaging analysis

NASA Astrophysics Data System (ADS)

Yang, Xiubin; Jin, Guang; Jiang, Li; Dai, Lu; Xu, Kai

2010-11-01

The Earth's digital elevation which impacts space camera imaging has prepared and imaging has analysed. Based on matching error that TDI CCD integral series request of the speed of image motion, statistical experimental methods-Monte Carlo method is used to calculate the distribution histogram of Earth's elevation in image motion compensated model which includes satellite attitude changes, orbital angular rate changes, latitude, longitude and the orbital inclination changes. And then, elevation information of the earth's surface from SRTM is read. Earth elevation map which produced for aerospace electronic cameras is compressed and spliced. It can get elevation data from flash according to the shooting point of latitude and longitude. If elevation data between two data, the ways of searching data uses linear interpolation. Linear interpolation can better meet the rugged mountains and hills changing requests. At last, the deviant framework and camera controller are used to test the character of deviant angle errors, TDI CCD camera simulation system with the material point corresponding to imaging point model is used to analyze the imaging's MTF and mutual correlation similarity measure, simulation system use adding cumulation which TDI CCD imaging exceeded the corresponding pixel horizontal and vertical offset to simulate camera imaging when stability of satellite attitude changes. This process is practicality. It can effectively control the camera memory space, and meet a very good precision TDI CCD camera in the request matches the speed of image motion and imaging.

Nuclear Radiation Degradation Study on HD Camera Based on CMOS Image Sensor at Different Dose Rates

PubMed Central

Wang, Congzheng; Hu, Song; Gao, Chunming; Feng, Chang

2018-01-01

In this work, we irradiated a high-definition (HD) industrial camera based on a commercial-off-the-shelf (COTS) CMOS image sensor (CIS) with Cobalt-60 gamma-rays. All components of the camera under test were fabricated without radiation hardening, except for the lens. The irradiation experiments of the HD camera under biased conditions were carried out at 1.0, 10.0, 20.0, 50.0 and 100.0 Gy/h. During the experiment, we found that the tested camera showed a remarkable degradation after irradiation and differed in the dose rates. With the increase of dose rate, the same target images become brighter. Under the same dose rate, the radiation effect in bright area is lower than that in dark area. Under different dose rates, the higher the dose rate is, the worse the radiation effect will be in both bright and dark areas. And the standard deviations of bright and dark areas become greater. Furthermore, through the progressive degradation analysis of the captured image, experimental results demonstrate that the attenuation of signal to noise ratio (SNR) versus radiation time is not obvious at the same dose rate, and the degradation is more and more serious with increasing dose rate. Additionally, the decrease rate of SNR at 20.0, 50.0 and 100.0 Gy/h is far greater than that at 1.0 and 10.0 Gy/h. Even so, we confirm that the HD industrial camera is still working at 10.0 Gy/h during the 8 h of measurements, with a moderate decrease of the SNR (5 dB). The work is valuable and can provide suggestion for camera users in the radiation field. PMID:29419782

Visible camera imaging of plasmas in Proto-MPEX

NASA Astrophysics Data System (ADS)

Mosby, R.; Skeen, C.; Biewer, T. M.; Renfro, R.; Ray, H.; Shaw, G. C.

2015-11-01

The prototype Material Plasma Exposure eXperiment (Proto-MPEX) is a linear plasma device being developed at Oak Ridge National Laboratory (ORNL). This machine plans to study plasma-material interaction (PMI) physics relevant to future fusion reactors. Measurements of plasma light emission will be made on Proto-MPEX using fast, visible framing cameras. The cameras utilize a global shutter, which allows a full frame image of the plasma to be captured and compared at multiple times during the plasma discharge. Typical exposure times are ~10-100 microseconds. The cameras are capable of capturing images at up to 18,000 frames per second (fps). However, the frame rate is strongly dependent on the size of the ``region of interest'' that is sampled. The maximum ROI corresponds to the full detector area, of ~1000x1000 pixels. The cameras have an internal gain, which controls the sensitivity of the 10-bit detector. The detector includes a Bayer filter, for ``true-color'' imaging of the plasma emission. This presentation will exmine the optimized camera settings for use on Proto-MPEX. This work was supported by the US. D.O.E. contract DE-AC05-00OR22725.

Establishing imaging sensor specifications for digital still cameras

NASA Astrophysics Data System (ADS)

Kriss, Michael A.

2007-02-01

Digital Still Cameras, DSCs, have now displaced conventional still cameras in most markets. The heart of a DSC is thought to be the imaging sensor, be it Full Frame CCD, and Interline CCD, a CMOS sensor or the newer Foveon buried photodiode sensors. There is a strong tendency by consumers to consider only the number of mega-pixels in a camera and not to consider the overall performance of the imaging system, including sharpness, artifact control, noise, color reproduction, exposure latitude and dynamic range. This paper will provide a systematic method to characterize the physical requirements of an imaging sensor and supporting system components based on the desired usage. The analysis is based on two software programs that determine the "sharpness", potential for artifacts, sensor "photographic speed", dynamic range and exposure latitude based on the physical nature of the imaging optics, sensor characteristics (including size of pixels, sensor architecture, noise characteristics, surface states that cause dark current, quantum efficiency, effective MTF, and the intrinsic full well capacity in terms of electrons per square centimeter). Examples will be given for consumer, pro-consumer, and professional camera systems. Where possible, these results will be compared to imaging system currently on the market.

High resolution bone mineral densitometry with a gamma camera

NASA Technical Reports Server (NTRS)

Leblanc, A.; Evans, H.; Jhingran, S.; Johnson, P.

1983-01-01

A technique by which the regional distribution of bone mineral can be determined in bone samples from small animals is described. The technique employs an Anger camera interfaced to a medical computer. High resolution imaging is possible by producing magnified images of the bone samples. Regional densitometry of femurs from oophorectomised and bone mineral loss.

Evaluation of a CdTe semiconductor based compact γ camera for sentinel lymph node imaging.

PubMed

Russo, Paolo; Curion, Assunta S; Mettivier, Giovanni; Esposito, Michela; Aurilio, Michela; Caracò, Corradina; Aloj, Luigi; Lastoria, Secondo

2011-03-01

The authors assembled a prototype compact gamma-ray imaging probe (MediPROBE) for sentinel lymph node (SLN) localization. This probe is based on a semiconductor pixel detector. Its basic performance was assessed in the laboratory and clinically in comparison with a conventional gamma camera. The room-temperature CdTe pixel detector (1 mm thick) has 256 x 256 square pixels arranged with a 55 microm pitch (sensitive area 14.08 x 14.08 mm2), coupled pixel-by-pixel via bump-bonding to the Medipix2 photon-counting readout CMOS integrated circuit. The imaging probe is equipped with a set of three interchangeable knife-edge pinhole collimators (0.94, 1.2, or 2.1 mm effective diameter at 140 keV) and its focal distance can be regulated in order to set a given field of view (FOV). A typical FOV of 70 mm at 50 mm skin-to-collimator distance corresponds to a minification factor 1:5. The detector is operated at a single low-energy threshold of about 20 keV. For 99 mTc, at 50 mm distance, a background-subtracted sensitivity of 6.5 x 10(-3) cps/kBq and a system spatial resolution of 5.5 mm FWHM were obtained for the 0.94 mm pinhole; corresponding values for the 2.1 mm pinhole were 3.3 x 10(-2) cps/kBq and 12.6 mm. The dark count rate was 0.71 cps. Clinical images in three patients with melanoma indicate detection of the SLNs with acquisition times between 60 and 410 s with an injected activity of 26 MBq 99 mTc and prior localization with standard gamma camera lymphoscintigraphy. The laboratory performance of this imaging probe is limited by the pinhole collimator performance and the necessity of working in minification due to the limited detector size. However, in clinical operative conditions, the CdTe imaging probe was effective in detecting SLNs with adequate resolution and an acceptable sensitivity. Sensitivity is expected to improve with the future availability of a larger CdTe detector permitting operation at shorter distances from the patient skin.

Space-variant restoration of images degraded by camera motion blur.

PubMed

Sorel, Michal; Flusser, Jan

2008-02-01

We examine the problem of restoration from multiple images degraded by camera motion blur. We consider scenes with significant depth variations resulting in space-variant blur. The proposed algorithm can be applied if the camera moves along an arbitrary curve parallel to the image plane, without any rotations. The knowledge of camera trajectory and camera parameters is not necessary. At the input, the user selects a region where depth variations are negligible. The algorithm belongs to the group of variational methods that estimate simultaneously a sharp image and a depth map, based on the minimization of a cost functional. To initialize the minimization, it uses an auxiliary window-based depth estimation algorithm. Feasibility of the algorithm is demonstrated by three experiments with real images.

Emission computerized axial tomography from multiple gamma-camera views using frequency filtering.

PubMed

Pelletier, J L; Milan, C; Touzery, C; Coitoux, P; Gailliard, P; Budinger, T F

1980-01-01

Emission computerized axial tomography is achievable in any nuclear medicine department from multiple gamma camera views. Data are collected by rotating the patient in front of the camera. A simple fast algorithm is implemented, known as the convolution technique: first the projection data are Fourier transformed and then an original filter designed for optimizing resolution and noise suppression is applied; finally the inverse transform of the latter operation is back-projected. This program, which can also take into account the attenuation for single photon events, was executed with good results on phantoms and patients. We think that it can be easily implemented for specific diagnostic problems.

Automatic visibility retrieval from thermal camera images

NASA Astrophysics Data System (ADS)

Dizerens, Céline; Ott, Beat; Wellig, Peter; Wunderle, Stefan

2017-10-01

This study presents an automatic visibility retrieval of a FLIR A320 Stationary Thermal Imager installed on a measurement tower on the mountain Lagern located in the Swiss Jura Mountains. Our visibility retrieval makes use of edges that are automatically detected from thermal camera images. Predefined target regions, such as mountain silhouettes or buildings with high thermal differences to the surroundings, are used to derive the maximum visibility distance that is detectable in the image. To allow a stable, automatic processing, our procedure additionally removes noise in the image and includes automatic image alignment to correct small shifts of the camera. We present a detailed analysis of visibility derived from more than 24000 thermal images of the years 2015 and 2016 by comparing them to (1) visibility derived from a panoramic camera image (VISrange), (2) measurements of a forward-scatter visibility meter (Vaisala FD12 working in the NIR spectra), and (3) modeled visibility values using the Thermal Range Model TRM4. Atmospheric conditions, mainly water vapor from European Center for Medium Weather Forecast (ECMWF), were considered to calculate the extinction coefficients using MODTRAN. The automatic visibility retrieval based on FLIR A320 images is often in good agreement with the retrieval from the systems working in different spectral ranges. However, some significant differences were detected as well, depending on weather conditions, thermal differences of the monitored landscape, and defined target size.

Reduced administered activity, reduced acquisition time, and preserved image quality for the new CZT camera.

PubMed

Oddstig, Jenny; Hedeer, Fredrik; Jögi, Jonas; Carlsson, Marcus; Hindorf, Cecilia; Engblom, Henrik

2013-02-01

For a 1-day myocardial perfusion SPECT (MPS) the recommendations for administered activity stated in the EANM guidelines results in an effective dose of up to 16 mSv per patient. Recently, a gamma camera system, based on cadmium zinc telluride (CZT) technology, was introduced. This technique has the potential to reduce the effective dose and scan time compared to the conventional NaI gamma camera. The aim of this study was to investigate if the effective dose can be reduced with a preserved image quality using CZT technology in MPS. In total, 150 patients were included in the study. All underwent a 1-day (99m)Tc-tetrofosmin stress-rest protocol and were divided into three subgroups (n = 50 in each group) with 4, 3, and 2.5 MBq/kg body weight of administered activity in the stress examination, respectively. The acquisition time was increased in proportion to the decrease in administered activity. All examinations were analyzed for image quality by visual grading on a 4-point scale (1 = poor, 2 = adequate, 3 = good, 4 = excellent), by two expert readers. The total effective dose (stress + rest) decreased from 9.3 to 5.8 mSv comparing 4 to 2.5 MBq/kg body weight. For the patients undergoing stress examination only (35%) the effective dose, administrating 2.5 MBq/kg, was 1.4 mSv. The image acquisition times for 2.5 MBq/kg body weight were 475 and 300 seconds (stress and rest) compared to 900 seconds for each when using conventional MPS. The average image quality was 3.7 ± 0.5, 3.8 ± 0.5, and 3.8 ± 0.4 for the stress images and 3.5 ± 0.6, 3.6 ± 0.6, and 3.5 ± 0.6 for the rest images and showed no statistically significant difference (P = .62) among the 4, 3, and 2.5 MBq/kg groups. The new CZT technology can be used to considerably decrease the effective dose and acquisition time for MPS with preserved high image quality.

The next evolution in radioguided surgery: breast cancer related sentinel node localization using a freehandSPECT-mobile gamma camera combination

PubMed Central

Engelen, Thijs; Winkel, Beatrice MF; Rietbergen, Daphne DD; KleinJan, Gijs H; Vidal-Sicart, Sergi; Olmos, Renato A Valdés; van den Berg, Nynke S; van Leeuwen, Fijs WB

2015-01-01

Accurate pre- and intraoperative identification of the sentinel node (SN) forms the basis of the SN biopsy procedure. Gamma tracing technologies such as a gamma probe (GP), a 2D mobile gamma camera (MGC) or 3D freehandSPECT (FHS) can be used to provide the surgeon with radioguidance to the SN(s). We reasoned that integrated use of these technologies results in the generation of a “hybrid” modality that combines the best that the individual radioguidance technologies have to offer. The sensitivity and resolvability of both 2D-MGC and 3D-FHS-MGC were studied in a phantom setup (at various source-detector depths and using varying injection site-to-SN distances), and in ten breast cancer patients scheduled for SN biopsy. Acquired 3D-FHS-MGC images were overlaid with the position of the phantom/patient. This augmented-reality overview image was then used for navigation to the hotspot/SN in virtual-reality using the GP. Obtained results were compared to conventional gamma camera lymphoscintigrams. Resolution of 3D-FHS-MGC allowed identification of the SNs at a minimum injection site (100 MBq)-to-node (1 MBq; 1%) distance of 20 mm, up to a source-detector depth of 36 mm in 2D-MGC and up to 24 mm in 3D-FHS-MGC. A clinically relevant dose of approximately 1 MBq was clearly detectable up to a depth of 60 mm in 2D-MGC and 48 mm in 3D-FHS-MGC. In all ten patients at least one SN was visualized on the lymphoscintigrams with a total of 12 SNs visualized. 3D-FHS-MGC identified 11 of 12 SNs and allowed navigation to all these visualized SNs; in one patient with two axillary SNs located closely to each other (11 mm), 3D-FHS-MGC was not able to distinguish the two SNs. In conclusion, high sensitivity detection of SNs at an injection site-to-node distance of 20 mm-and-up was possible using 3D-FHS-MGC. In patients, 3D-FHS-MGC showed highly reproducible images as compared to the conventional lymphoscintigrams. PMID:26069857

Demosaicing images from colour cameras for digital image correlation

NASA Astrophysics Data System (ADS)

Forsey, A.; Gungor, S.

2016-11-01

Digital image correlation is not the intended use for consumer colour cameras, but with care they can be successfully employed in such a role. The main obstacle is the sparsely sampled colour data caused by the use of a colour filter array (CFA) to separate the colour channels. It is shown that the method used to convert consumer camera raw files into a monochrome image suitable for digital image correlation (DIC) can have a significant effect on the DIC output. A number of widely available software packages and two in-house methods are evaluated in terms of their performance when used with DIC. Using an in-plane rotating disc to produce a highly constrained displacement field, it was found that the bicubic spline based in-house demosaicing method outperformed the other methods in terms of accuracy and aliasing suppression.

Line-Constrained Camera Location Estimation in Multi-Image Stereomatching.

PubMed

Donné, Simon; Goossens, Bart; Philips, Wilfried

2017-08-23

Stereomatching is an effective way of acquiring dense depth information from a scene when active measurements are not possible. So-called lightfield methods take a snapshot from many camera locations along a defined trajectory (usually uniformly linear or on a regular grid-we will assume a linear trajectory) and use this information to compute accurate depth estimates. However, they require the locations for each of the snapshots to be known: the disparity of an object between images is related to both the distance of the camera to the object and the distance between the camera positions for both images. Existing solutions use sparse feature matching for camera location estimation. In this paper, we propose a novel method that uses dense correspondences to do the same, leveraging an existing depth estimation framework to also yield the camera locations along the line. We illustrate the effectiveness of the proposed technique for camera location estimation both visually for the rectification of epipolar plane images and quantitatively with its effect on the resulting depth estimation. Our proposed approach yields a valid alternative for sparse techniques, while still being executed in a reasonable time on a graphics card due to its highly parallelizable nature.

Digital readout for image converter cameras

NASA Astrophysics Data System (ADS)

Honour, Joseph

1991-04-01

There is an increasing need for fast and reliable analysis of recorded sequences from image converter cameras so that experimental information can be readily evaluated without recourse to more time consuming photographic procedures. A digital readout system has been developed using a randomly triggerable high resolution CCD camera, the output of which is suitable for use with IBM AT compatible PC. Within half a second from receipt of trigger pulse, the frame reformatter displays the image and transfer to storage media can be readily achieved via the PC and dedicated software. Two software programmes offer different levels of image manipulation which includes enhancement routines and parameter calculations with accuracy down to pixel levels. Hard copy prints can be acquired using a specially adapted Polaroid printer, outputs for laser and video printer extend the overall versatility of the system.

A time-resolved image sensor for tubeless streak cameras

NASA Astrophysics Data System (ADS)

Yasutomi, Keita; Han, SangMan; Seo, Min-Woong; Takasawa, Taishi; Kagawa, Keiichiro; Kawahito, Shoji

2014-03-01

This paper presents a time-resolved CMOS image sensor with draining-only modulation (DOM) pixels for tube-less streak cameras. Although the conventional streak camera has high time resolution, the device requires high voltage and bulky system due to the structure with a vacuum tube. The proposed time-resolved imager with a simple optics realize a streak camera without any vacuum tubes. The proposed image sensor has DOM pixels, a delay-based pulse generator, and a readout circuitry. The delay-based pulse generator in combination with an in-pixel logic allows us to create and to provide a short gating clock to the pixel array. A prototype time-resolved CMOS image sensor with the proposed pixel is designed and implemented using 0.11um CMOS image sensor technology. The image array has 30(Vertical) x 128(Memory length) pixels with the pixel pitch of 22.4um. .

Laser line scan underwater imaging by complementary metal-oxide-semiconductor camera

NASA Astrophysics Data System (ADS)

He, Zhiyi; Luo, Meixing; Song, Xiyu; Wang, Dundong; He, Ning

2017-12-01

This work employs the complementary metal-oxide-semiconductor (CMOS) camera to acquire images in a scanning manner for laser line scan (LLS) underwater imaging to alleviate backscatter impact of seawater. Two operating features of the CMOS camera, namely the region of interest (ROI) and rolling shutter, can be utilized to perform image scan without the difficulty of translating the receiver above the target as the traditional LLS imaging systems have. By the dynamically reconfigurable ROI of an industrial CMOS camera, we evenly divided the image into five subareas along the pixel rows and then scanned them by changing the ROI region automatically under the synchronous illumination by the fun beams of the lasers. Another scanning method was explored by the rolling shutter operation of the CMOS camera. The fun beam lasers were turned on/off to illuminate the narrow zones on the target in a good correspondence to the exposure lines during the rolling procedure of the camera's electronic shutter. The frame synchronization between the image scan and the laser beam sweep may be achieved by either the strobe lighting output pulse or the external triggering pulse of the industrial camera. Comparison between the scanning and nonscanning images shows that contrast of the underwater image can be improved by our LLS imaging techniques, with higher stability and feasibility than the mechanically controlled scanning method.

Image quality testing of assembled IR camera modules

NASA Astrophysics Data System (ADS)

Winters, Daniel; Erichsen, Patrik

2013-10-01

Infrared (IR) camera modules for the LWIR (8-12_m) that combine IR imaging optics with microbolometer focal plane array (FPA) sensors with readout electronics are becoming more and more a mass market product. At the same time, steady improvements in sensor resolution in the higher priced markets raise the requirement for imaging performance of objectives and the proper alignment between objective and FPA. This puts pressure on camera manufacturers and system integrators to assess the image quality of finished camera modules in a cost-efficient and automated way for quality control or during end-of-line testing. In this paper we present recent development work done in the field of image quality testing of IR camera modules. This technology provides a wealth of additional information in contrast to the more traditional test methods like minimum resolvable temperature difference (MRTD) which give only a subjective overall test result. Parameters that can be measured are image quality via the modulation transfer function (MTF) for broadband or with various bandpass filters on- and off-axis and optical parameters like e.g. effective focal length (EFL) and distortion. If the camera module allows for refocusing the optics, additional parameters like best focus plane, image plane tilt, auto-focus quality, chief ray angle etc. can be characterized. Additionally, the homogeneity and response of the sensor with the optics can be characterized in order to calculate the appropriate tables for non-uniformity correction (NUC). The technology can also be used to control active alignment methods during mechanical assembly of optics to high resolution sensors. Other important points that are discussed are the flexibility of the technology to test IR modules with different form factors, electrical interfaces and last but not least the suitability for fully automated measurements in mass production.

Performance of the prototype LaBr{sub 3} spectrometer developed for the JET gamma-ray camera upgrade

DOE Office of Scientific and Technical Information (OSTI.GOV)

Rigamonti, D., E-mail: davide.rigamonti@mib.infn.it; Nocente, M.; Gorini, G.

2016-11-15

In this work, we describe the solution developed by the gamma ray camera upgrade enhancement project to improve the spectroscopic properties of the existing JET γ-ray camera. Aim of the project is to enable gamma-ray spectroscopy in JET deuterium-tritium plasmas. A dedicated pilot spectrometer based on a LaBr{sub 3} crystal coupled to a silicon photo-multiplier has been developed. A proper pole zero cancellation network able to shorten the output signal to a length of 120 ns has been implemented allowing for spectroscopy at MHz count rates. The system has been characterized in the laboratory and shows an energy resolution ofmore » 5.5% at E{sub γ} = 0.662 MeV, which extrapolates favorably in the energy range of interest for gamma-ray emission from fast ions in fusion plasmas.« less

A comparison of select image-compression algorithms for an electronic still camera

NASA Technical Reports Server (NTRS)

Nerheim, Rosalee

1989-01-01

This effort is a study of image-compression algorithms for an electronic still camera. An electronic still camera can record and transmit high-quality images without the use of film, because images are stored digitally in computer memory. However, high-resolution images contain an enormous amount of information, and will strain the camera's data-storage system. Image compression will allow more images to be stored in the camera's memory. For the electronic still camera, a compression algorithm that produces a reconstructed image of high fidelity is most important. Efficiency of the algorithm is the second priority. High fidelity and efficiency are more important than a high compression ratio. Several algorithms were chosen for this study and judged on fidelity, efficiency and compression ratio. The transform method appears to be the best choice. At present, the method is compressing images to a ratio of 5.3:1 and producing high-fidelity reconstructed images.

The core of the nearby S0 galaxy NGC 7457 imaged with the HST planetary camera

NASA Technical Reports Server (NTRS)

Lauer, Tod R.; Faber, S. M.; Holtzman, Jon A.; Baum, William A.; Currie, Douglas G.; Ewald, S. P.; Groth, Edward J.; Hester, J. Jeff; Kelsall, T.

1991-01-01

A brief analysis is presented of images of the nearby S0 galaxy NGC 7457 obtained with the HST Planetary Camera. While the galaxy remains unresolved with the HST, the images reveal that any core most likely has r(c) less than 0.052 arcsec. The light distribution is consistent with a gamma = -1.0 power law inward to the resolution limit, with a possible stellar nucleus with luminosity of 10 million solar. This result represents the first observation outside the Local Group of a galaxy nucleus at this spatial resolution, and it suggests that such small, high surface brightness cores may be common.

Imaging Emission Spectra with Handheld and Cellphone Cameras

NASA Astrophysics Data System (ADS)

Sitar, David

2012-12-01

As point-and-shoot digital camera technology advances it is becoming easier to image spectra in a laboralory setting on a shoestring budget and get immediale results. With this in mind, I wanted to test three cameras to see how their results would differ. Two undergraduate physics students and I used one handheld 7.1 megapixel (MP) digital Cannon point-and-shoot auto focusing camera and two different cellphone cameras: one at 6.1 MP and the other at 5.1 MP.

Breast-specific gamma camera imaging with 99mTc-MIBI has better diagnostic performance than magnetic resonance imaging in breast cancer patients: A meta-analysis.

PubMed

Zhang, Aimi; Li, Panli; Liu, Qiufang; Song, Shaoli

2017-01-01

This study aimed to evaluate the diagnostic role of breast-specific gamma camera imaging (BSGI) with technetium-99m-methoxy isobutyl isonitrile ( 99m Tc-MIBI) and magnetic resonance imaging (MRI) in patients with breast cancer through a meta-analysis. Three reviewers searched articles published in medical journals before June 2016 in MEDLINE, EMBASE and Springer Databases; the references listed in original articles were also retrieved. We used the quality assessment of diagnostic accuracy studies (QUADAS) tool to assess the quality of the included studies. Heterogeneity, pooled sensitivity and specificity, positive likelihood ratio, negative likelihood ratio, diagnostic odds ratio (DOR) and summary receiver operating characteristic (SROC) curves were calculated by Meta-DiSc software to estimate the diagnostic performance of BSGI and MRI. Ten studies with 517 patients were included after meeting the inclusion criteria. We did a subgroup analysis of the same data type. The pooled sensitivities of BSGI and MRI were: 0.84 (95% CI, 0.79-0.88) and 0.89 (95% CI, 0.84-0.92) respectively, and the pooled specificities of BSGI and MRI were: 0.82 (95% CI, 0.74-0.88) and 0.39 (95% CI, 0.30-0.49) respectively. The areas under the SROC curve of BSGI and MRI were 0.93 and 0.72 respectively. The results of our meta-analysis indicated that compared with MRI, BSGI has similar sensitivity, higher specificity, better diagnostic performance, and can be widely used in clinical practice.

A fast algorithm for computer aided collimation gamma camera (CACAO)

NASA Astrophysics Data System (ADS)

Jeanguillaume, C.; Begot, S.; Quartuccio, M.; Douiri, A.; Franck, D.; Pihet, P.; Ballongue, P.

2000-08-01

The computer aided collimation gamma camera is aimed at breaking down the resolution sensitivity trade-off of the conventional parallel hole collimator. It uses larger and longer holes, having an added linear movement at the acquisition sequence. A dedicated algorithm including shift and sum, deconvolution, parabolic filtering and rotation is described. Examples of reconstruction are given. This work shows that a simple and fast algorithm, based on a diagonal dominant approximation of the problem can be derived. Its gives a practical solution to the CACAO reconstruction problem.

Microchannel plate streak camera

DOEpatents

Wang, Ching L.

1989-01-01

An improved streak camera in which a microchannel plate electron multiplier is used in place of or in combination with the photocathode used in prior streak cameras. The improved streak camera is far more sensitive to photons (UV to gamma-rays) than the conventional x-ray streak camera which uses a photocathode. The improved streak camera offers gamma-ray detection with high temporal resolution. It also offers low-energy x-ray detection without attenuation inside the cathode. Using the microchannel plate in the improved camera has resulted in a time resolution of about 150 ps, and has provided a sensitivity sufficient for 1000 KeV x-rays.

Application of single-image camera calibration for ultrasound augmented laparoscopic visualization

NASA Astrophysics Data System (ADS)

Liu, Xinyang; Su, He; Kang, Sukryool; Kane, Timothy D.; Shekhar, Raj

2015-03-01

Accurate calibration of laparoscopic cameras is essential for enabling many surgical visualization and navigation technologies such as the ultrasound-augmented visualization system that we have developed for laparoscopic surgery. In addition to accuracy and robustness, there is a practical need for a fast and easy camera calibration method that can be performed on demand in the operating room (OR). Conventional camera calibration methods are not suitable for the OR use because they are lengthy and tedious. They require acquisition of multiple images of a target pattern in its entirety to produce satisfactory result. In this work, we evaluated the performance of a single-image camera calibration tool (rdCalib; Percieve3D, Coimbra, Portugal) featuring automatic detection of corner points in the image, whether partial or complete, of a custom target pattern. Intrinsic camera parameters of a 5-mm and a 10-mm standard Stryker® laparoscopes obtained using rdCalib and the well-accepted OpenCV camera calibration method were compared. Target registration error (TRE) as a measure of camera calibration accuracy for our optical tracking-based AR system was also compared between the two calibration methods. Based on our experiments, the single-image camera calibration yields consistent and accurate results (mean TRE = 1.18 ± 0.35 mm for the 5-mm scope and mean TRE = 1.13 ± 0.32 mm for the 10-mm scope), which are comparable to the results obtained using the OpenCV method with 30 images. The new single-image camera calibration method is promising to be applied to our augmented reality visualization system for laparoscopic surgery.

Application of single-image camera calibration for ultrasound augmented laparoscopic visualization

PubMed Central

Liu, Xinyang; Su, He; Kang, Sukryool; Kane, Timothy D.; Shekhar, Raj

2017-01-01

Accurate calibration of laparoscopic cameras is essential for enabling many surgical visualization and navigation technologies such as the ultrasound-augmented visualization system that we have developed for laparoscopic surgery. In addition to accuracy and robustness, there is a practical need for a fast and easy camera calibration method that can be performed on demand in the operating room (OR). Conventional camera calibration methods are not suitable for the OR use because they are lengthy and tedious. They require acquisition of multiple images of a target pattern in its entirety to produce satisfactory result. In this work, we evaluated the performance of a single-image camera calibration tool (rdCalib; Percieve3D, Coimbra, Portugal) featuring automatic detection of corner points in the image, whether partial or complete, of a custom target pattern. Intrinsic camera parameters of a 5-mm and a 10-mm standard Stryker® laparoscopes obtained using rdCalib and the well-accepted OpenCV camera calibration method were compared. Target registration error (TRE) as a measure of camera calibration accuracy for our optical tracking-based AR system was also compared between the two calibration methods. Based on our experiments, the single-image camera calibration yields consistent and accurate results (mean TRE = 1.18 ± 0.35 mm for the 5-mm scope and mean TRE = 1.13 ± 0.32 mm for the 10-mm scope), which are comparable to the results obtained using the OpenCV method with 30 images. The new single-image camera calibration method is promising to be applied to our augmented reality visualization system for laparoscopic surgery. PMID:28943703

Application of single-image camera calibration for ultrasound augmented laparoscopic visualization.

PubMed

Liu, Xinyang; Su, He; Kang, Sukryool; Kane, Timothy D; Shekhar, Raj

2015-03-01

Accurate calibration of laparoscopic cameras is essential for enabling many surgical visualization and navigation technologies such as the ultrasound-augmented visualization system that we have developed for laparoscopic surgery. In addition to accuracy and robustness, there is a practical need for a fast and easy camera calibration method that can be performed on demand in the operating room (OR). Conventional camera calibration methods are not suitable for the OR use because they are lengthy and tedious. They require acquisition of multiple images of a target pattern in its entirety to produce satisfactory result. In this work, we evaluated the performance of a single-image camera calibration tool ( rdCalib ; Percieve3D, Coimbra, Portugal) featuring automatic detection of corner points in the image, whether partial or complete, of a custom target pattern. Intrinsic camera parameters of a 5-mm and a 10-mm standard Stryker ® laparoscopes obtained using rdCalib and the well-accepted OpenCV camera calibration method were compared. Target registration error (TRE) as a measure of camera calibration accuracy for our optical tracking-based AR system was also compared between the two calibration methods. Based on our experiments, the single-image camera calibration yields consistent and accurate results (mean TRE = 1.18 ± 0.35 mm for the 5-mm scope and mean TRE = 1.13 ± 0.32 mm for the 10-mm scope), which are comparable to the results obtained using the OpenCV method with 30 images. The new single-image camera calibration method is promising to be applied to our augmented reality visualization system for laparoscopic surgery.

Imaging of breast cancer with mid- and long-wave infrared camera.

PubMed

Joro, R; Lääperi, A-L; Dastidar, P; Soimakallio, S; Kuukasjärvi, T; Toivonen, T; Saaristo, R; Järvenpää, R

2008-01-01

In this novel study the breasts of 15 women with palpable breast cancer were preoperatively imaged with three technically different infrared (IR) cameras - micro bolometer (MB), quantum well (QWIP) and photo voltaic (PV) - to compare their ability to differentiate breast cancer from normal tissue. The IR images were processed, the data for frequency analysis were collected from dynamic IR images by pixel-based analysis and from each image selectively windowed regional analysis was carried out, based on angiogenesis and nitric oxide production of cancer tissue causing vasomotor and cardiogenic frequency differences compared to normal tissue. Our results show that the GaAs QWIP camera and the InSb PV camera demonstrate the frequency difference between normal and cancerous breast tissue; the PV camera more clearly. With selected image processing operations more detailed frequency analyses could be applied to the suspicious area. The MB camera was not suitable for tissue differentiation, as the difference between noise and effective signal was unsatisfactory.

Applying image quality in cell phone cameras: lens distortion

NASA Astrophysics Data System (ADS)

Baxter, Donald; Goma, Sergio R.; Aleksic, Milivoje

2009-01-01

This paper describes the framework used in one of the pilot studies run under the I3A CPIQ initiative to quantify overall image quality in cell-phone cameras. The framework is based on a multivariate formalism which tries to predict overall image quality from individual image quality attributes and was validated in a CPIQ pilot program. The pilot study focuses on image quality distortions introduced in the optical path of a cell-phone camera, which may or may not be corrected in the image processing path. The assumption is that the captured image used is JPEG compressed and the cellphone camera is set to 'auto' mode. As the used framework requires that the individual attributes to be relatively perceptually orthogonal, in the pilot study, the attributes used are lens geometric distortion (LGD) and lateral chromatic aberrations (LCA). The goal of this paper is to present the framework of this pilot project starting with the definition of the individual attributes, up to their quantification in JNDs of quality, a requirement of the multivariate formalism, therefore both objective and subjective evaluations were used. A major distinction in the objective part from the 'DSC imaging world' is that the LCA/LGD distortions found in cell-phone cameras, rarely exhibit radial behavior, therefore a radial mapping/modeling cannot be used in this case.

Coincidence ion imaging with a fast frame camera

NASA Astrophysics Data System (ADS)

Lee, Suk Kyoung; Cudry, Fadia; Lin, Yun Fei; Lingenfelter, Steven; Winney, Alexander H.; Fan, Lin; Li, Wen

2014-12-01

A new time- and position-sensitive particle detection system based on a fast frame CMOS (complementary metal-oxide semiconductors) camera is developed for coincidence ion imaging. The system is composed of four major components: a conventional microchannel plate/phosphor screen ion imager, a fast frame CMOS camera, a single anode photomultiplier tube (PMT), and a high-speed digitizer. The system collects the positional information of ions from a fast frame camera through real-time centroiding while the arrival times are obtained from the timing signal of a PMT processed by a high-speed digitizer. Multi-hit capability is achieved by correlating the intensity of ion spots on each camera frame with the peak heights on the corresponding time-of-flight spectrum of a PMT. Efficient computer algorithms are developed to process camera frames and digitizer traces in real-time at 1 kHz laser repetition rate. We demonstrate the capability of this system by detecting a momentum-matched co-fragments pair (methyl and iodine cations) produced from strong field dissociative double ionization of methyl iodide.

Coincidence ion imaging with a fast frame camera

DOE Office of Scientific and Technical Information (OSTI.GOV)

Lee, Suk Kyoung; Cudry, Fadia; Lin, Yun Fei

2014-12-15

A new time- and position-sensitive particle detection system based on a fast frame CMOS (complementary metal-oxide semiconductors) camera is developed for coincidence ion imaging. The system is composed of four major components: a conventional microchannel plate/phosphor screen ion imager, a fast frame CMOS camera, a single anode photomultiplier tube (PMT), and a high-speed digitizer. The system collects the positional information of ions from a fast frame camera through real-time centroiding while the arrival times are obtained from the timing signal of a PMT processed by a high-speed digitizer. Multi-hit capability is achieved by correlating the intensity of ion spots onmore » each camera frame with the peak heights on the corresponding time-of-flight spectrum of a PMT. Efficient computer algorithms are developed to process camera frames and digitizer traces in real-time at 1 kHz laser repetition rate. We demonstrate the capability of this system by detecting a momentum-matched co-fragments pair (methyl and iodine cations) produced from strong field dissociative double ionization of methyl iodide.« less

Portal imaging with flat-panel detector and CCD camera

NASA Astrophysics Data System (ADS)

Roehrig, Hans; Tang, Chuankun; Cheng, Chee-Wai; Dallas, William J.

1997-07-01

This paper provides a comparison of imaging parameters of two portal imaging systems at 6 MV: a flat panel detector and a CCD-camera based portal imaging system. Measurements were made of the signal and noise and consequently of signal-to-noise per pixel as a function of the exposure. Both systems have a linear response with respect to exposure, and the noise is proportional to the square-root of the exposure, indicating photon-noise limitation. The flat-panel detector has a signal- to-noise ratio, which is higher than that observed wit the CCD-camera based portal imaging system. This is expected because most portal imaging systems using optical coupling with a lens exhibit severe quantum-sinks. The paper also presents data on the screen's photon gain (the number of light-photons per interacting x-ray photon), as well as on the magnitude of the Swank-noise, (which describes fluctuation in the screen's photon gain). Images of a Las Vegas-type aluminum contrast detail phantom, located at the ISO-Center, were generated at an exposure of 1 MU. The CCD-camera based system permits detection of aluminum-holes of 0.01194 cm diameter and 0.228 mm depth while the flat-panel detector permits detection of aluminum holes of 0.01194 cm diameter and 0.1626 mm depth, indicating a better signal-to-noise ratio. Rank order filtering was applied to the raw images from the CCD-based system in order to remove the direct hits. These are camera responses to scattered x-ray photons which interact directly with the CCD of the CCD-camera and generate 'salt and pepper type noise,' which interferes severely with attempts to determine accurate estimates of the image noise.

The GCT camera for the Cherenkov Telescope Array

NASA Astrophysics Data System (ADS)

Lapington, J. S.; Abchiche, A.; Allan, D.; Amans, J.-P.; Armstrong, T. P.; Balzer, A.; Berge, D.; Boisson, C.; Bousquet, J.-J.; Bose, R.; Brown, A. M.; Bryan, M.; Buchholtz, G.; Buckley, J.; Chadwick, P. M.; Costantini, H.; Cotter, G.; Daniel, M. K.; De Franco, A.; De Frondat, F.; Dournaux, J.-L.; Dumas, D.; Ernenwein, J.-P.; Fasola, G.; Funk, S.; Gironnet, J.; Graham, J. A.; Greenshaw, T.; Hervet, O.; Hidaka, N.; Hinton, J. A.; Huet, J.-M.; Jankowsky, D.; Jegouzo, I.; Jogler, T.; Kawashima, T.; Kraus, M.; Laporte, P.; Leach, S.; Lefaucheur, J.; Markoff, S.; Melse, T.; Minaya, I. A.; Mohrmann, L.; Molyneux, P.; Moore, P.; Nolan, S. J.; Okumura, A.; Osborne, J. P.; Parsons, R. D.; Rosen, S.; Ross, D.; Rowell, G.; Rulten, C. B.; Sato, Y.; Sayede, F.; Schmoll, J.; Schoorlemmer, H.; Servillat, M.; Sol, H.; Stamatescu, V.; Stephan, M.; Stuik, R.; Sykes, J.; Tajima, H.; Thornhill, J.; Tibaldo, L.; Trichard, C.; Varner, G.; Vink, J.; Watson, J. J.; White, R.; Yamane, N.; Zech, A.; Zink, A.; Zorn, J.; CTA Consortium

2017-12-01

The Gamma Cherenkov Telescope (GCT) is one of the designs proposed for the Small Sized Telescope (SST) section of the Cherenkov Telescope Array (CTA). The GCT uses dual-mirror optics, resulting in a compact telescope with good image quality and a large field of view with a smaller, more economical, camera than is achievable with conventional single mirror solutions. The photon counting GCT camera is designed to record the flashes of atmospheric Cherenkov light from gamma and cosmic ray initiated cascades, which last only a few tens of nanoseconds. The GCT optics require that the camera detectors follow a convex surface with a radius of curvature of 1 m and a diameter of 35 cm, which is approximated by tiling the focal plane with 32 modules. The first camera prototype is equipped with multi-anode photomultipliers, each comprising an 8×8 array of 6×6 mm2 pixels to provide the required angular scale, adding up to 2048 pixels in total. Detector signals are shaped, amplified and digitised by electronics based on custom ASICs that provide digitisation at 1 GSample/s. The camera is self-triggering, retaining images where the focal plane light distribution matches predefined spatial and temporal criteria. The electronics are housed in the liquid-cooled, sealed camera enclosure. LED flashers at the corners of the focal plane provide a calibration source via reflection from the secondary mirror. The first GCT camera prototype underwent preliminary laboratory tests last year. In November 2015, the camera was installed on a prototype GCT telescope (SST-GATE) in Paris and was used to successfully record the first Cherenkov light of any CTA prototype, and the first Cherenkov light seen with such a dual-mirror optical system. A second full-camera prototype based on Silicon Photomultipliers is under construction. Up to 35 GCTs are envisaged for CTA.

An image compression algorithm for a high-resolution digital still camera

NASA Technical Reports Server (NTRS)

Nerheim, Rosalee

1989-01-01

The Electronic Still Camera (ESC) project will provide for the capture and transmission of high-quality images without the use of film. The image quality will be superior to video and will approach the quality of 35mm film. The camera, which will have the same general shape and handling as a 35mm camera, will be able to send images to earth in near real-time. Images will be stored in computer memory (RAM) in removable cartridges readable by a computer. To save storage space, the image will be compressed and reconstructed at the time of viewing. Both lossless and loss-y image compression algorithms are studied, described, and compared.

A low-count reconstruction algorithm for Compton-based prompt gamma imaging

NASA Astrophysics Data System (ADS)

Huang, Hsuan-Ming; Liu, Chih-Chieh; Jan, Meei-Ling; Lee, Ming-Wei

2018-04-01

The Compton camera is an imaging device which has been proposed to detect prompt gammas (PGs) produced by proton–nuclear interactions within tissue during proton beam irradiation. Compton-based PG imaging has been developed to verify proton ranges because PG rays, particularly characteristic ones, have strong correlations with the distribution of the proton dose. However, accurate image reconstruction from characteristic PGs is challenging because the detector efficiency and resolution are generally low. Our previous study showed that point spread functions can be incorporated into the reconstruction process to improve image resolution. In this study, we proposed a low-count reconstruction algorithm to improve the image quality of a characteristic PG emission by pooling information from other characteristic PG emissions. PGs were simulated from a proton beam irradiated on a water phantom, and a two-stage Compton camera was used for PG detection. The results show that the image quality of the reconstructed characteristic PG emission is improved with our proposed method in contrast to the standard reconstruction method using events from only one characteristic PG emission. For the 4.44 MeV PG rays, both methods can be used to predict the positions of the peak and the distal falloff with a mean accuracy of 2 mm. Moreover, only the proposed method can improve the estimated positions of the peak and the distal falloff of 5.25 MeV PG rays, and a mean accuracy of 2 mm can be reached.

Plenoptic particle image velocimetry with multiple plenoptic cameras

NASA Astrophysics Data System (ADS)

Fahringer, Timothy W.; Thurow, Brian S.

2018-07-01

Plenoptic particle image velocimetry was recently introduced as a viable three-dimensional, three-component velocimetry technique based on light field cameras. One of the main benefits of this technique is its single camera configuration allowing the technique to be applied in facilities with limited optical access. The main drawback of this configuration is decreased accuracy in the out-of-plane dimension. This work presents a solution with the addition of a second plenoptic camera in a stereo-like configuration. A framework for reconstructing volumes with multiple plenoptic cameras including the volumetric calibration and reconstruction algorithms, including: integral refocusing, filtered refocusing, multiplicative refocusing, and MART are presented. It is shown that the addition of a second camera improves the reconstruction quality and removes the ‘cigar’-like elongation associated with the single camera system. In addition, it is found that adding a third camera provides minimal improvement. Further metrics of the reconstruction quality are quantified in terms of a reconstruction algorithm, particle density, number of cameras, camera separation angle, voxel size, and the effect of common image noise sources. In addition, a synthetic Gaussian ring vortex is used to compare the accuracy of the single and two camera configurations. It was determined that the addition of a second camera reduces the RMSE velocity error from 1.0 to 0.1 voxels in depth and 0.2 to 0.1 voxels in the lateral spatial directions. Finally, the technique is applied experimentally on a ring vortex and comparisons are drawn from the four presented reconstruction algorithms, where it was found that MART and multiplicative refocusing produced the cleanest vortex structure and had the least shot-to-shot variability. Filtered refocusing is able to produce the desired structure, albeit with more noise and variability, while integral refocusing struggled to produce a coherent vortex ring.

Impact of Image Noise on Gamma Index Calculation

NASA Astrophysics Data System (ADS)

Chen, M.; Mo, X.; Parnell, D.; Olivera, G.; Galmarini, D.; Lu, W.

2014-03-01

Purpose: The Gamma Index defines an asymmetric metric between the evaluated image and the reference image. It provides a quantitative comparison that can be used to indicate sample-wised pass/fail on the agreement of the two images. The Gamma passing/failing rate has become an important clinical evaluation tool. However, the presence of noise in the evaluated and/or reference images may change the Gamma Index, hence the passing/failing rate, and further, clinical decisions. In this work, we systematically studied the impact of the image noise on the Gamma Index calculation. Methods: We used both analytic formulation and numerical calculations in our study. The numerical calculations included simulations and clinical images. Three different noise scenarios were studied in simulations: noise in reference images only, in evaluated images only, and in both. Both white and spatially correlated noises of various magnitudes were simulated. For clinical images of various noise levels, the Gamma Index of measurement against calculation, calculation against measurement, and measurement against measurement, were evaluated. Results: Numerical calculations for both the simulation and clinical data agreed with the analytic formulations, and the clinical data agreed with the simulations. For the Gamma Index of measurement against calculation, its distribution has an increased mean and an increased standard deviation as the noise increases. On the contrary, for the Gamma index of calculation against measurement, its distribution has a decreased mean and stabilized standard deviation as the noise increases. White noise has greater impact on the Gamma Index than spatially correlated noise. Conclusions: The noise has significant impact on the Gamma Index calculation and the impact is asymmetric. The Gamma Index should be reported along with the noise levels in both reference and evaluated images. Reporting of the Gamma Index with switched roles of the images as reference and

Cheetah: A high frame rate, high resolution SWIR image camera

NASA Astrophysics Data System (ADS)

Neys, Joel; Bentell, Jonas; O'Grady, Matt; Vermeiren, Jan; Colin, Thierry; Hooylaerts, Peter; Grietens, Bob

2008-10-01

A high resolution, high frame rate InGaAs based image sensor and associated camera has been developed. The sensor and the camera are capable of recording and delivering more than 1700 full 640x512pixel frames per second. The FPA utilizes a low lag CTIA current integrator in each pixel, enabling integration times shorter than one microsecond. On-chip logics allows for four different sub windows to be read out simultaneously at even higher rates. The spectral sensitivity of the FPA is situated in the SWIR range [0.9-1.7 μm] and can be further extended into the Visible and NIR range. The Cheetah camera has max 16 GB of on-board memory to store the acquired images and transfer the data over a Gigabit Ethernet connection to the PC. The camera is also equipped with a full CameralinkTM interface to directly stream the data to a frame grabber or dedicated image processing unit. The Cheetah camera is completely under software control.

A comparison of two prompt gamma imaging techniques with collimator-based cameras for range verification in proton therapy

NASA Astrophysics Data System (ADS)

Lin, Hsin-Hon; Chang, Hao-Ting; Chao, Tsi-Chian; Chuang, Keh-Shih

2017-08-01

In vivo range verification plays an important role in proton therapy to fully utilize the benefits of the Bragg peak (BP) for delivering high radiation dose to tumor, while sparing the normal tissue. For accurately locating the position of BP, camera equipped with collimators (multi-slit and knife-edge collimator) to image prompt gamma (PG) emitted along the proton tracks in the patient have been proposed for range verification. The aim of the work is to compare the performance of multi-slit collimator and knife-edge collimator for non-invasive proton beam range verification. PG imaging was simulated by a validated GATE/GEANT4 Monte Carlo code to model the spot-scanning proton therapy and cylindrical PMMA phantom in detail. For each spot, 108 protons were simulated. To investigate the correlation between the acquired PG profile and the proton range, the falloff regions of PG profiles were fitted with a 3-line-segment curve function as the range estimate. Factors including the energy window setting, proton energy, phantom size, and phantom shift that may influence the accuracy of detecting range were studied. Results indicated that both collimator systems achieve reasonable accuracy and good response to the phantom shift. The accuracy of range predicted by multi-slit collimator system is less affected by the proton energy, while knife-edge collimator system can achieve higher detection efficiency that lead to a smaller deviation in predicting range. We conclude that both collimator systems have potentials for accurately range monitoring in proton therapy. It is noted that neutron contamination has a marked impact on range prediction of the two systems, especially in multi-slit system. Therefore, a neutron reduction technique for improving the accuracy of range verification of proton therapy is needed.

Camera Development for the Cherenkov Telescope Array

NASA Astrophysics Data System (ADS)

Moncada, Roberto Jose

2017-01-01

With the Cherenkov Telescope Array (CTA), the very-high-energy gamma-ray universe, between 30 GeV and 300 TeV, will be probed at an unprecedented resolution, allowing deeper studies of known gamma-ray emitters and the possible discovery of new ones. This exciting project could also confirm the particle nature of dark matter by looking for the gamma rays produced by self-annihilating weakly interacting massive particles (WIMPs). The telescopes will use the imaging atmospheric Cherenkov technique (IACT) to record Cherenkov photons that are produced by the gamma-ray induced extensive air shower. One telescope design features dual-mirror Schwarzschild-Couder (SC) optics that allows the light to be finely focused on the high-resolution silicon photomultipliers of the camera modules starting from a 9.5-meter primary mirror. Each camera module will consist of a focal plane module and front-end electronics, and will have four TeV Array Readout with GSa/s Sampling and Event Trigger (TARGET) chips, giving them 64 parallel input channels. The TARGET chip has a self-trigger functionality for readout that can be used in higher logic across camera modules as well as across individual telescopes, which will each have 177 camera modules. There will be two sites, one in the northern and the other in the southern hemisphere, for full sky coverage, each spanning at least one square kilometer. A prototype SC telescope is currently under construction at the Fred Lawrence Whipple Observatory in Arizona. This work was supported by the National Science Foundation's REU program through NSF award AST-1560016.

Megapixel mythology and photospace: estimating photospace for camera phones from large image sets

NASA Astrophysics Data System (ADS)

Hultgren, Bror O.; Hertel, Dirk W.

2008-01-01

It is a myth that more pixels alone result in better images. The marketing of camera phones in particular has focused on their pixel numbers. However, their performance varies considerably according to the conditions of image capture. Camera phones are often used in low-light situations where the lack of a flash and limited exposure time will produce underexposed, noisy and blurred images. Camera utilization can be quantitatively described by photospace distributions, a statistical description of the frequency of pictures taken at varying light levels and camera-subject distances. If the photospace distribution is known, the user-experienced distribution of quality can be determined either directly by direct measurement of subjective quality, or by photospace-weighting of objective attributes. The population of a photospace distribution requires examining large numbers of images taken under typical camera phone usage conditions. ImagePhi was developed as a user-friendly software tool to interactively estimate the primary photospace variables, subject illumination and subject distance, from individual images. Additionally, subjective evaluations of image quality and failure modes for low quality images can be entered into ImagePhi. ImagePhi has been applied to sets of images taken by typical users with a selection of popular camera phones varying in resolution. The estimated photospace distribution of camera phone usage has been correlated with the distributions of failure modes. The subjective and objective data show that photospace conditions have a much bigger impact on image quality of a camera phone than the pixel count of its imager. The 'megapixel myth' is thus seen to be less a myth than an ill framed conditional assertion, whose conditions are to a large extent specified by the camera's operational state in photospace.

Toward an image compression algorithm for the high-resolution electronic still camera

NASA Technical Reports Server (NTRS)

Nerheim, Rosalee

1989-01-01

Taking pictures with a camera that uses a digital recording medium instead of film has the advantage of recording and transmitting images without the use of a darkroom or a courier. However, high-resolution images contain an enormous amount of information and strain data-storage systems. Image compression will allow multiple images to be stored in the High-Resolution Electronic Still Camera. The camera is under development at Johnson Space Center. Fidelity of the reproduced image and compression speed are of tantamount importance. Lossless compression algorithms are fast and faithfully reproduce the image, but their compression ratios will be unacceptably low due to noise in the front end of the camera. Future efforts will include exploring methods that will reduce the noise in the image and increase the compression ratio.

ARNICA, the NICMOS 3 imaging camera of TIRGO.

NASA Astrophysics Data System (ADS)

Lisi, F.; Baffa, C.; Hunt, L.; Stanga, R.

ARNICA (ARcetri Near Infrared CAmera) is the imaging camera for the near infrared bands between 1.0 and 2.5 μm that Arcetri Observatory has designed and built as a general facility for the TIRGO telescope (1.5 m diameter, f/20) located at Gornergrat (Switzerland). The scale is 1″per pixel, with sky coverage of more than 4 min×4 min on the NICMOS 3 (256×256 pixels, 40 μm side) detector array. The camera is remotely controlled by a PC 486, connected to the array control electronics via a fiber-optics link. A C-language package, running under MS-DOS on the PC 486, acquires and stores the frames, and controls the timing of the array. The camera is intended for imaging of large extra-galactic and Galactic fields; a large effort has been dedicated to explore the possibility of achieving precise photometric measurements in the J, H, K astronomical bands, with very promising results.

X-ray imaging using digital cameras

NASA Astrophysics Data System (ADS)

Winch, Nicola M.; Edgar, Andrew

2012-03-01

The possibility of using the combination of a computed radiography (storage phosphor) cassette and a semiprofessional grade digital camera for medical or dental radiography is investigated. We compare the performance of (i) a Canon 5D Mk II single lens reflex camera with f1.4 lens and full-frame CMOS array sensor and (ii) a cooled CCD-based camera with a 1/3 frame sensor and the same lens system. Both systems are tested with 240 x 180 mm cassettes which are based on either powdered europium-doped barium fluoride bromide or needle structure europium-doped cesium bromide. The modulation transfer function for both systems has been determined and falls to a value of 0.2 at around 2 lp/mm, and is limited by light scattering of the emitted light from the storage phosphor rather than the optics or sensor pixelation. The modulation transfer function for the CsBr:Eu2+ plate is bimodal, with a high frequency wing which is attributed to the light-guiding behaviour of the needle structure. The detective quantum efficiency has been determined using a radioisotope source and is comparatively low at 0.017 for the CMOS camera and 0.006 for the CCD camera, attributed to the poor light harvesting by the lens. The primary advantages of the method are portability, robustness, digital imaging and low cost; the limitations are the low detective quantum efficiency and hence signal-to-noise ratio for medical doses, and restricted range of plate sizes. Representative images taken with medical doses are shown and illustrate the potential use for portable basic radiography.

A low-cost dual-camera imaging system for aerial applicators

USDA-ARS?s Scientific Manuscript database

Agricultural aircraft provide a readily available remote sensing platform as low-cost and easy-to-use consumer-grade cameras are being increasingly used for aerial imaging. In this article, we report on a dual-camera imaging system we recently assembled that can capture RGB and near-infrared (NIR) i...

Relating transverse ray error and light fields in plenoptic camera images

NASA Astrophysics Data System (ADS)

Schwiegerling, Jim; Tyo, J. Scott

2013-09-01

Plenoptic cameras have emerged in recent years as a technology for capturing light field data in a single snapshot. A conventional digital camera can be modified with the addition of a lenslet array to create a plenoptic camera. The camera image is focused onto the lenslet array. The lenslet array is placed over the camera sensor such that each lenslet forms an image of the exit pupil onto the sensor. The resultant image is an array of circular exit pupil images, each corresponding to the overlying lenslet. The position of the lenslet encodes the spatial information of the scene, whereas as the sensor pixels encode the angular information for light incident on the lenslet. The 4D light field is therefore described by the 2D spatial information and 2D angular information captured by the plenoptic camera. In aberration theory, the transverse ray error relates the pupil coordinates of a given ray to its deviation from the ideal image point in the image plane and is consequently a 4D function as well. We demonstrate a technique for modifying the traditional transverse ray error equations to recover the 4D light field of a general scene. In the case of a well corrected optical system, this light field is easily related to the depth of various objects in the scene. Finally, the effects of sampling with both the lenslet array and the camera sensor on the 4D light field data are analyzed to illustrate the limitations of such systems.

CMOS Imaging Sensor Technology for Aerial Mapping Cameras

NASA Astrophysics Data System (ADS)

Neumann, Klaus; Welzenbach, Martin; Timm, Martin

2016-06-01

In June 2015 Leica Geosystems launched the first large format aerial mapping camera using CMOS sensor technology, the Leica DMC III. This paper describes the motivation to change from CCD sensor technology to CMOS for the development of this new aerial mapping camera. In 2002 the DMC first generation was developed by Z/I Imaging. It was the first large format digital frame sensor designed for mapping applications. In 2009 Z/I Imaging designed the DMC II which was the first digital aerial mapping camera using a single ultra large CCD sensor to avoid stitching of smaller CCDs. The DMC III is now the third generation of large format frame sensor developed by Z/I Imaging and Leica Geosystems for the DMC camera family. It is an evolution of the DMC II using the same system design with one large monolithic PAN sensor and four multi spectral camera heads for R,G, B and NIR. For the first time a 391 Megapixel large CMOS sensor had been used as PAN chromatic sensor, which is an industry record. Along with CMOS technology goes a range of technical benefits. The dynamic range of the CMOS sensor is approx. twice the range of a comparable CCD sensor and the signal to noise ratio is significantly better than with CCDs. Finally results from the first DMC III customer installations and test flights will be presented and compared with other CCD based aerial sensors.

Image Mosaicking Approach for a Double-Camera System in the GaoFen2 Optical Remote Sensing Satellite Based on the Big Virtual Camera.

PubMed

Cheng, Yufeng; Jin, Shuying; Wang, Mi; Zhu, Ying; Dong, Zhipeng

2017-06-20

The linear array push broom imaging mode is widely used for high resolution optical satellites (HROS). Using double-cameras attached by a high-rigidity support along with push broom imaging is one method to enlarge the field of view while ensuring high resolution. High accuracy image mosaicking is the key factor of the geometrical quality of complete stitched satellite imagery. This paper proposes a high accuracy image mosaicking approach based on the big virtual camera (BVC) in the double-camera system on the GaoFen2 optical remote sensing satellite (GF2). A big virtual camera can be built according to the rigorous imaging model of a single camera; then, each single image strip obtained by each TDI-CCD detector can be re-projected to the virtual detector of the big virtual camera coordinate system using forward-projection and backward-projection to obtain the corresponding single virtual image. After an on-orbit calibration and relative orientation, the complete final virtual image can be obtained by stitching the single virtual images together based on their coordinate information on the big virtual detector image plane. The paper subtly uses the concept of the big virtual camera to obtain a stitched image and the corresponding high accuracy rational function model (RFM) for concurrent post processing. Experiments verified that the proposed method can achieve seamless mosaicking while maintaining the geometric accuracy.

The Advanced Gamma-ray Imaging System (AGIS): Telescope Mechanical Designs

NASA Astrophysics Data System (ADS)

Guarino, V.; Buckley, J.; Byrum, K.; Falcone, A.; Fegan, S.; Finley, J.; Hanna, D.; Horan, D.; Kaaret, P.; Konopelko, A.; Krawczynski, H.; Krennrich, F.; Wagner, R.; Woods, M.; Vassiliev, V.

2008-04-01

The concept of a future ground-based gamma-ray observatory, AGIS, in the energy range 40 GeV-100 TeV is based on an array of sim 100 imaging atmospheric Cherenkov telescopes (IACTs). The anticipated improvements of AGIS sensitivity, angular resolution and reliability of operation impose demanding technological and cost requirements on the design of IACTs. The relatively inexpensive Davies-Cotton telescope design has been used in ground-based gamma-ray astronomy for almost fifty years and is an excellent option. We are also exploring alternative designs and in this submission we focus on the recent mechanical design of a two-mirror telescope with a Schwarzschild-Couder (SC) optical system. The mechanical structure provides support points for mirrors and camera. The design was driven by the requirement of minimizing the deflections of the mirror support structures. The structure is also designed to be able to slew in elevation and azimuth at 10 degrees/sec.

The added value of a portable gamma camera for intraoperative detection of sentinel lymph node in squamous cell carcinoma of the oral cavity: A case report.

PubMed

Mayoral, M; Paredes, P; Sieira, R; Vidal-Sicart, S; Marti, C; Pons, F

2014-01-01

The use of sentinel lymph node biopsy in squamous cell carcinoma of the oral cavity is still subject to debate although some studies have reported its feasibility. The main reason for this debate is probably due to the high false-negative rate for floor-of-mouth tumors per se. We report the case of a 54-year-old man with a T1N0 floor-of-mouth squamous cell carcinoma who underwent the sentinel lymph node procedure. Lymphoscintigraphy and SPECT/CT imaging were performed for lymphatic mapping with a conventional gamma camera. Sentinel lymph nodes were identified at right Ib, left IIa and Ia levels. However, these sentinel lymph nodes were difficult to detect intraoperatively with a gamma probe owing to the activity originating from the injection site. The use of a portable gamma camera made it possible to localize and excise all the sentinel lymph nodes. This case demonstrates the usefulness of this tool to improve sentinel lymph node detecting in floor-of-mouth tumors, especially those close to the injection area. Copyright © 2013 Elsevier España, S.L. and SEMNIM. All rights reserved.

Image dynamic range test and evaluation of Gaofen-2 dual cameras

NASA Astrophysics Data System (ADS)

Zhang, Zhenhua; Gan, Fuping; Wei, Dandan

2015-12-01

In order to fully understand the dynamic range of Gaofen-2 satellite data and support the data processing, application and next satellites development, in this article, we evaluated the dynamic range by calculating some statistics such as maximum ,minimum, average and stand deviation of four images obtained at the same time by Gaofen-2 dual cameras in Beijing area; then the maximum ,minimum, average and stand deviation of each longitudinal overlap of PMS1,PMS2 were calculated respectively for the evaluation of each camera's dynamic range consistency; and these four statistics of each latitudinal overlap of PMS1,PMS2 were calculated respectively for the evaluation of the dynamic range consistency between PMS1 and PMS2 at last. The results suggest that there is a wide dynamic range of DN value in the image obtained by PMS1 and PMS2 which contains rich information of ground objects; in general, the consistency of dynamic range between the single camera images is in close agreement, but also a little difference, so do the dual cameras. The consistency of dynamic range between the single camera images is better than the dual cameras'.

UCXp camera imaging principle and key technologies of data post-processing

NASA Astrophysics Data System (ADS)

Yuan, Fangyan; Li, Guoqing; Zuo, Zhengli; Liu, Jianmin; Wu, Liang; Yu, Xiaoping; Zhao, Haitao

2014-03-01

The large format digital aerial camera product UCXp was introduced into the Chinese market in 2008, the image consists of 17310 columns and 11310 rows with a pixel size of 6 mm. The UCXp camera has many advantages compared with the same generation camera, with multiple lenses exposed almost at the same time and no oblique lens. The camera has a complex imaging process whose principle will be detailed in this paper. On the other hand, the UCXp image post-processing method, including data pre-processing and orthophoto production, will be emphasized in this article. Based on the data of new Beichuan County, this paper will describe the data processing and effects.

New opportunities for quality enhancing of images captured by passive THz camera

NASA Astrophysics Data System (ADS)

Trofimov, Vyacheslav A.; Trofimov, Vladislav V.

2014-10-01

As it is well-known, the passive THz camera allows seeing concealed object without contact with a person and this camera is non-dangerous for a person. Obviously, efficiency of using the passive THz camera depends on its temperature resolution. This characteristic specifies possibilities of the detection for concealed object: minimal size of the object; maximal distance of the detection; image quality. Computer processing of the THz image may lead to many times improving of the image quality without any additional engineering efforts. Therefore, developing of modern computer code for its application to THz images is urgent problem. Using appropriate new methods one may expect such temperature resolution which will allow to see banknote in pocket of a person without any real contact. Modern algorithms for computer processing of THz images allow also to see object inside the human body using a temperature trace on the human skin. This circumstance enhances essentially opportunity of passive THz camera applications for counterterrorism problems. We demonstrate opportunities, achieved at present time, for the detection both of concealed objects and of clothes components due to using of computer processing of images captured by passive THz cameras, manufactured by various companies. Another important result discussed in the paper consists in observation of both THz radiation emitted by incandescent lamp and image reflected from ceramic floorplate. We consider images produced by THz passive cameras manufactured by Microsemi Corp., and ThruVision Corp., and Capital Normal University (Beijing, China). All algorithms for computer processing of the THz images under consideration in this paper were developed by Russian part of author list. Keywords: THz wave, passive imaging camera, computer processing, security screening, concealed and forbidden objects, reflected image, hand seeing, banknote seeing, ceramic floorplate, incandescent lamp.

Parallel phase-sensitive three-dimensional imaging camera

DOEpatents

Smithpeter, Colin L.; Hoover, Eddie R.; Pain, Bedabrata; Hancock, Bruce R.; Nellums, Robert O.

2007-09-25

An apparatus is disclosed for generating a three-dimensional (3-D) image of a scene illuminated by a pulsed light source (e.g. a laser or light-emitting diode). The apparatus, referred to as a phase-sensitive 3-D imaging camera utilizes a two-dimensional (2-D) array of photodetectors to receive light that is reflected or scattered from the scene and processes an electrical output signal from each photodetector in the 2-D array in parallel using multiple modulators, each having inputs of the photodetector output signal and a reference signal, with the reference signal provided to each modulator having a different phase delay. The output from each modulator is provided to a computational unit which can be used to generate intensity and range information for use in generating a 3-D image of the scene. The 3-D camera is capable of generating a 3-D image using a single pulse of light, or alternately can be used to generate subsequent 3-D images with each additional pulse of light.

High-Resolution Mars Camera Test Image of Moon (Infrared)

NASA Technical Reports Server (NTRS)

2005-01-01

This crescent view of Earth's Moon in infrared wavelengths comes from a camera test by NASA's Mars Reconnaissance Orbiter spacecraft on its way to Mars. The mission's High Resolution Imaging Science Experiment camera took the image on Sept. 8, 2005, while at a distance of about 10 million kilometers (6 million miles) from the Moon. The dark feature on the right is Mare Crisium. From that distance, the Moon would appear as a star-like point of light to the unaided eye. The test verified the camera's focusing capability and provided an opportunity for calibration. The spacecraft's Context Camera and Optical Navigation Camera also performed as expected during the test.

The Mars Reconnaissance Orbiter, launched on Aug. 12, 2005, is on course to reach Mars on March 10, 2006. After gradually adjusting the shape of its orbit for half a year, it will begin its primary science phase in November 2006. From the mission's planned science orbit about 300 kilometers (186 miles) above the surface of Mars, the high resolution camera will be able to discern features as small as one meter or yard across.

Extreme ultra-violet movie camera for imaging microsecond time scale magnetic reconnection

DOE Office of Scientific and Technical Information (OSTI.GOV)

Chai, Kil-Byoung; Bellan, Paul M.

2013-12-15

An ultra-fast extreme ultra-violet (EUV) movie camera has been developed for imaging magnetic reconnection in the Caltech spheromak/astrophysical jet experiment. The camera consists of a broadband Mo:Si multilayer mirror, a fast decaying YAG:Ce scintillator, a visible light block, and a high-speed visible light CCD camera. The camera can capture EUV images as fast as 3.3 × 10{sup 6} frames per second with 0.5 cm spatial resolution. The spectral range is from 20 eV to 60 eV. EUV images reveal strong, transient, highly localized bursts of EUV radiation when magnetic reconnection occurs.

A Comparative Study of Microscopic Images Captured by a Box Type Digital Camera Versus a Standard Microscopic Photography Camera Unit

PubMed Central

Desai, Nandini J.; Gupta, B. D.; Patel, Pratik Narendrabhai

2014-01-01

Introduction: Obtaining images of slides viewed by a microscope can be invaluable for both diagnosis and teaching.They can be transferred among technologically-advanced hospitals for further consultation and evaluation. But a standard microscopic photography camera unit (MPCU)(MIPS-Microscopic Image projection System) is costly and not available in resource poor settings. The aim of our endeavour was to find a comparable and cheaper alternative method for photomicrography. Materials and Methods: We used a NIKON Coolpix S6150 camera (box type digital camera) with Olympus CH20i microscope and a fluorescent microscope for the purpose of this study. Results: We got comparable results for capturing images of light microscopy, but the results were not as satisfactory for fluorescent microscopy. Conclusion: A box type digital camera is a comparable, less expensive and convenient alternative to microscopic photography camera unit. PMID:25478350

Ultrahigh sensitivity endoscopic camera using a new CMOS image sensor: providing with clear images under low illumination in addition to fluorescent images.

PubMed

Aoki, Hisae; Yamashita, Hiromasa; Mori, Toshiyuki; Fukuyo, Tsuneo; Chiba, Toshio

2014-11-01

We developed a new ultrahigh-sensitive CMOS camera using a specific sensor that has a wide range of spectral sensitivity characteristics. The objective of this study is to present our updated endoscopic technology that has successfully integrated two innovative functions; ultrasensitive imaging as well as advanced fluorescent viewing. Two different experiments were conducted. One was carried out to evaluate the function of the ultrahigh-sensitive camera. The other was to test the availability of the newly developed sensor and its performance as a fluorescence endoscope. In both studies, the distance from the endoscopic tip to the target was varied and those endoscopic images in each setting were taken for further comparison. In the first experiment, the 3-CCD camera failed to display the clear images under low illumination, and the target was hardly seen. In contrast, the CMOS camera was able to display the targets regardless of the camera-target distance under low illumination. Under high illumination, imaging quality given by both cameras was quite alike. In the second experiment as a fluorescence endoscope, the CMOS camera was capable of clearly showing the fluorescent-activated organs. The ultrahigh sensitivity CMOS HD endoscopic camera is expected to provide us with clear images under low illumination in addition to the fluorescent images under high illumination in the field of laparoscopic surgery.

Prompt-gamma monitoring in hadrontherapy: A review

NASA Astrophysics Data System (ADS)

Krimmer, J.; Dauvergne, D.; Létang, J. M.; Testa, É.

2018-01-01

Secondary radiation emission induced by nuclear reactions is correlated to the path of ions in matter. Therefore, such penetrating radiation can be used for in vivo control of hadrontherapy treatments, for which the primary beam is absorbed inside the patient. Among secondary radiations, prompt-gamma rays were proposed for real-time verification of ion range. Such a verification is a desired condition to reduce uncertainties in treatment planning. For more than a decade, efforts have been undertaken worldwide to promote prompt-gamma-based devices to be used in clinical conditions. Dedicated cameras are necessary to overcome the challenges of a broad- and high-energy distribution, a large background, high instantaneous count rates, and compatibility constraints with patient irradiation. Several types of prompt-gamma imaging devices have been proposed, that are either physically-collimated or electronically collimated (Compton cameras). Clinical tests are now undergoing. Meanwhile, other methods than direct prompt-gamma imaging were proposed, that are based on specific counting using either time-of-flight or photon energy measurements. In the present article, we make a review and discuss the state of the art for all techniques using prompt-gamma detection to improve the quality assurance in hadrontherapy.

Imaging Emission Spectra with Handheld and Cellphone Cameras

ERIC Educational Resources Information Center

Sitar, David

2012-01-01

As point-and-shoot digital camera technology advances it is becoming easier to image spectra in a laboratory setting on a shoestring budget and get immediate results. With this in mind, I wanted to test three cameras to see how their results would differ. Two undergraduate physics students and I used one handheld 7.1 megapixel (MP) digital Cannon…

Depth profile measurement with lenslet images of the plenoptic camera

NASA Astrophysics Data System (ADS)

Yang, Peng; Wang, Zhaomin; Zhang, Wei; Zhao, Hongying; Qu, Weijuan; Zhao, Haimeng; Asundi, Anand; Yan, Lei

2018-03-01

An approach for carrying out depth profile measurement of an object with the plenoptic camera is proposed. A single plenoptic image consists of multiple lenslet images. To begin with, these images are processed directly with a refocusing technique to obtain the depth map, which does not need to align and decode the plenoptic image. Then, a linear depth calibration is applied based on the optical structure of the plenoptic camera for depth profile reconstruction. One significant improvement of the proposed method concerns the resolution of the depth map. Unlike the traditional method, our resolution is not limited by the number of microlenses inside the camera, and the depth map can be globally optimized. We validated the method with experiments on depth map reconstruction, depth calibration, and depth profile measurement, with the results indicating that the proposed approach is both efficient and accurate.

[Diagnostic use of positron emission tomography in France: from the coincidence gamma-camera to mobile hybrid PET/CT devices].

PubMed

Talbot, Jean-Noël

2010-11-01

Positron emission tomography (PET) is a well-established medical imaging method. PET is increasingly used for diagnostic purposes, especially in oncology. The most widely used radiopharmaceutical is FDG, a glucose analogue. Other radiopharmaceuticals have recently been registered or are in development. We outline technical improvements of PET machines during more than a decade of clinical use in France. Even though image quality has improved considerably and PET-CT hybrid machines have emerged, spending per examination has remained remarkably constant. Replacement and maintenance costs have remained in the range of 170-190 Euros per examination since 1997, whether early CDET gamma cameras or the latest time-of-flight PET/CT devices are used. This is mainly due to shorter acquisition times and more efficient use of FDG New reimbursement rates for PET/CT are needed in France in order to favor regular acquisition of state-of-the-art devices. One major development is the coupling of PET and MR imaging.

Prompt gamma-ray imaging for small animals

NASA Astrophysics Data System (ADS)

Xu, Libai

Small animal imaging is recognized as a powerful discovery tool for small animal modeling of human diseases, which is providing an important clue to complete understanding of disease mechanisms and is helping researchers develop and test new treatments. The current small animal imaging techniques include positron emission tomography (PET), single photon emission tomography (SPECT), computed tomography (CT), magnetic resonance imaging (MRI), and ultrasound (US). A new imaging modality called prompt gamma-ray imaging (PGI) has been identified and investigated primarily by Monte Carlo simulation. Currently it is suggested for use on small animals. This new technique could greatly enhance and extend the present capabilities of PET and SPECT imaging from ingested radioisotopes to the imaging of selected non-radioactive elements, such as Gd, Cd, Hg, and B, and has the great potential to be used in Neutron Cancer Therapy to monitor neutron distribution and neutron-capture agent distribution. This approach consists of irradiating small animals in the thermal neutron beam of a nuclear reactor to produce prompt gamma rays from the elements in the sample by the radiative capture (n, gamma) reaction. These prompt gamma rays are emitted in energies that are characteristic of each element and they are also produced in characteristic coincident chains. After measuring these prompt gamma rays by surrounding spectrometry array, the distribution of each element of interest in the sample is reconstructed from the mapping of each detected signature gamma ray by either electronic collimations or mechanical collimations. In addition, the transmitted neutrons from the beam can be simultaneously used for very sensitive anatomical imaging, which provides the registration for the elemental distributions obtained from PGI. The primary approach is to use Monte Carlo simulation methods either with the specific purpose code CEARCPG, developed at NC State University or with the general purpose

Imaging of gamma-Irradiated Regions of a Crystal

NASA Technical Reports Server (NTRS)

Dragoi, Danut; McClure, Steven; Johnston, Allan; Chao, Tien-Hsin

2004-01-01

A holographic technique has been devised for generating a visible display of the effect of exposure of a photorefractive crystal to gamma rays. The technique exploits the space charge that results from trapping of electrons in defects induced by gamma rays. The technique involves a three-stage process. In the first stage, one writes a holographic pattern in the crystal by use of the apparatus shown in Figure 1. A laser beam of 532-nm wavelength is collimated and split into signal and reference beams by use of a polarizing beam splitter. On its way to the crystal, the reference beam goes through a two-dimensional optical scanner that contains two pairs of lenses (L1y, L2y and L1x,L2x) and mirrors M1 and M2, which can be rotated by use of micrometer drives to make fine adjustments. The signal beam is sent through a spatial light modulator that imposes the holographic pattern, then through two imaging lenses L(sub img) on its way to the crystal. An aperture is placed at the common focus of lenses Limg to suppress high-order diffraction from the spatial light modulator. The hologram is formed by interference between the signal and reference beams. A camera lens focuses an image of the interior of the crystal onto a charge-coupled device (CCD). If the crystal is illuminated by only the reference beam once the hologram has been formed, then an image of the hologram is formed on the CCD: this phenomenon is exploited to make visible the pattern of gamma irradiation of the crystal, as described next. In the second stage of the process, the crystal is removed from the holographic apparatus and irradiated with rays at a dose of about 100 krad. In the third stage of the process, the crystal is remounted in the holographic apparatus in the same position as in the first stage and illuminated with only the reference beam to obtain the image of the hologram as modified by the effect of the rays. The orientations of M1 and M2 can be adjusted slightly, if necessary, to maximize the

PSF reconstruction for Compton-based prompt gamma imaging

NASA Astrophysics Data System (ADS)

Jan, Meei-Ling; Lee, Ming-Wei; Huang, Hsuan-Ming

2018-02-01

Compton-based prompt gamma (PG) imaging has been proposed for in vivo range verification in proton therapy. However, several factors degrade the image quality of PG images, some of which are due to inherent properties of a Compton camera such as spatial resolution and energy resolution. Moreover, Compton-based PG imaging has a spatially variant resolution loss. In this study, we investigate the performance of the list-mode ordered subset expectation maximization algorithm with a shift-variant point spread function (LM-OSEM-SV-PSF) model. We also evaluate how well the PG images reconstructed using an SV-PSF model reproduce the distal falloff of the proton beam. The SV-PSF parameters were estimated from simulation data of point sources at various positions. Simulated PGs were produced in a water phantom irradiated with a proton beam. Compared to the LM-OSEM algorithm, the LM-OSEM-SV-PSF algorithm improved the quality of the reconstructed PG images and the estimation of PG falloff positions. In addition, the 4.44 and 5.25 MeV PG emissions can be accurately reconstructed using the LM-OSEM-SV-PSF algorithm. However, for the 2.31 and 6.13 MeV PG emissions, the LM-OSEM-SV-PSF reconstruction provides limited improvement. We also found that the LM-OSEM algorithm followed by a shift-variant Richardson-Lucy deconvolution could reconstruct images with quality visually similar to the LM-OSEM-SV-PSF-reconstructed images, while requiring shorter computation time.

Innovative Camera and Image Processing System to Characterize Cryospheric Changes

NASA Astrophysics Data System (ADS)

Schenk, A.; Csatho, B. M.; Nagarajan, S.

2010-12-01

The polar regions play an important role in Earth’s climatic and geodynamic systems. Digital photogrammetric mapping provides a means for monitoring the dramatic changes observed in the polar regions during the past decades. High-resolution, photogrammetrically processed digital aerial imagery provides complementary information to surface measurements obtained by laser altimetry systems. While laser points accurately sample the ice surface, stereo images allow for the mapping of features, such as crevasses, flow bands, shear margins, moraines, leads, and different types of sea ice. Tracking features in repeat images produces a dense velocity vector field that can either serve as validation for interferometrically derived surface velocities or it constitutes a stand-alone product. A multi-modal, photogrammetric platform consists of one or more high-resolution, commercial color cameras, GPS and inertial navigation system as well as optional laser scanner. Such a system, using a Canon EOS-1DS Mark II camera, was first flown on the Icebridge missions Fall 2009 and Spring 2010, capturing hundreds of thousands of images at a frame rate of about one second. While digital images and videos have been used for quite some time for visual inspection, precise 3D measurements with low cost, commercial cameras require special photogrammetric treatment that only became available recently. Calibrating the multi-camera imaging system and geo-referencing the images are absolute prerequisites for all subsequent applications. Commercial cameras are inherently non-metric, that is, their sensor model is only approximately known. Since these cameras are not as rugged as photogrammetric cameras, the interior orientation also changes, due to temperature and pressure changes and aircraft vibration, resulting in large errors in 3D measurements. It is therefore necessary to calibrate the cameras frequently, at least whenever the system is newly installed. Geo-referencing the images is

Presence capture cameras - a new challenge to the image quality

NASA Astrophysics Data System (ADS)

Peltoketo, Veli-Tapani

2016-04-01

Commercial presence capture cameras are coming to the markets and a new era of visual entertainment starts to get its shape. Since the true presence capturing is still a very new technology, the real technical solutions are just passed a prototyping phase and they vary a lot. Presence capture cameras have still the same quality issues to tackle as previous phases of digital imaging but also numerous new ones. This work concentrates to the quality challenges of presence capture cameras. A camera system which can record 3D audio-visual reality as it is has to have several camera modules, several microphones and especially technology which can synchronize output of several sources to a seamless and smooth virtual reality experience. Several traditional quality features are still valid in presence capture cameras. Features like color fidelity, noise removal, resolution and dynamic range create the base of virtual reality stream quality. However, co-operation of several cameras brings a new dimension for these quality factors. Also new quality features can be validated. For example, how the camera streams should be stitched together with 3D experience without noticeable errors and how to validate the stitching? The work describes quality factors which are still valid in the presence capture cameras and defines the importance of those. Moreover, new challenges of presence capture cameras are investigated in image and video quality point of view. The work contains considerations how well current measurement methods can be used in presence capture cameras.

Design and realization of an AEC&AGC system for the CCD aerial camera

NASA Astrophysics Data System (ADS)

Liu, Hai ying; Feng, Bing; Wang, Peng; Li, Yan; Wei, Hao yun

2015-08-01

An AEC and AGC(Automatic Exposure Control and Automatic Gain Control) system was designed for a CCD aerial camera with fixed aperture and electronic shutter. The normal AEC and AGE algorithm is not suitable to the aerial camera since the camera always takes high-resolution photographs in high-speed moving. The AEC and AGE system adjusts electronic shutter and camera gain automatically according to the target brightness and the moving speed of the aircraft. An automatic Gamma correction is used before the image is output so that the image is better for watching and analyzing by human eyes. The AEC and AGC system could avoid underexposure, overexposure, or image blurring caused by fast moving or environment vibration. A series of tests proved that the system meet the requirements of the camera system with its fast adjusting speed, high adaptability, high reliability in severe complex environment.

Test Image of Earth Rocks by Mars Camera Stereo

NASA Image and Video Library

2010-11-16

This stereo view of terrestrial rocks combines two images taken by a testing twin of the Mars Hand Lens Imager MAHLI camera on NASA Mars Science Laboratory. 3D glasses are necessary to view this image.

IR observations in gamma-ray blazars

NASA Technical Reports Server (NTRS)

Mahoney, W. A.; Gautier, T. N.; Ressler, M. E.; Wallyn, P.; Durouchoux, P.; Higdon, J. C.

1997-01-01

The infrared photometric and spectral observation of five gamma ray blazars in coordination with the energetic gamma ray experiment telescope (EGRET) onboard the Compton Gamma Ray Observatory is reported. The infrared measurements were made with a Cassegrain infrared camera and the mid-infrared large well imager at the Mt. Palomar 5 m telescope. The emphasis is on the three blazars observed simultaneously by EGRET and the ground-based telescope during viewing period 519. In addition to the acquisition of broadband spectral measurements for direct correlation with the 100 MeV EGRET observations, near infrared images were obtained, enabling a search for intra-day variability to be carried out.

Inexpensive Neutron Imaging Cameras Using CCDs for Astronomy

NASA Astrophysics Data System (ADS)

Hewat, A. W.

We have developed inexpensive neutron imaging cameras using CCDs originally designed for amateur astronomical observation. The low-light, high resolution requirements of such CCDs are similar to those for neutron imaging, except that noise as well as cost is reduced by using slower read-out electronics. For example, we use the same 2048x2048 pixel ;Kodak; KAI-4022 CCD as used in the high performance PCO-2000 CCD camera, but our electronics requires ∼5 sec for full-frame read-out, ten times slower than the PCO-2000. Since neutron exposures also require several seconds, this is not seen as a serious disadvantage for many applications. If higher frame rates are needed, the CCD unit on our camera can be easily swapped for a faster readout detector with similar chip size and resolution, such as the PCO-2000 or the sCMOS PCO.edge 4.2.

First On-Site True Gamma-Ray Imaging-Spectroscopy of Contamination near Fukushima Plant

PubMed Central

Tomono, Dai; Mizumoto, Tetsuya; Takada, Atsushi; Komura, Shotaro; Matsuoka, Yoshihiro; Mizumura, Yoshitaka; Oda, Makoto; Tanimori, Toru

2017-01-01

We have developed an Electron Tracking Compton Camera (ETCC), which provides a well-defined Point Spread Function (PSF) by reconstructing a direction of each gamma as a point and realizes simultaneous measurement of brightness and spectrum of MeV gamma-rays for the first time. Here, we present the results of our on-site pilot gamma-imaging-spectroscopy with ETCC at three contaminated locations in the vicinity of the Fukushima Daiichi Nuclear Power Plants in Japan in 2014. The obtained distribution of brightness (or emissivity) with remote-sensing observations is unambiguously converted into the dose distribution. We confirm that the dose distribution is consistent with the one taken by conventional mapping measurements with a dosimeter physically placed at each grid point. Furthermore, its imaging spectroscopy, boosted by Compton-edge-free spectra, reveals complex radioactive features in a quantitative manner around each individual target point in the background-dominated environment. Notably, we successfully identify a “micro hot spot” of residual caesium contamination even in an already decontaminated area. These results show that the ETCC performs exactly as the geometrical optics predicts, demonstrates its versatility in the field radiation measurement, and reveals potentials for application in many fields, including the nuclear industry, medical field, and astronomy. PMID:28155883

Recognizable-image selection for fingerprint recognition with a mobile-device camera.

PubMed

Lee, Dongjae; Choi, Kyoungtaek; Choi, Heeseung; Kim, Jaihie

2008-02-01

This paper proposes a recognizable-image selection algorithm for fingerprint-verification systems that use a camera embedded in a mobile device. A recognizable image is defined as the fingerprint image which includes the characteristics that are sufficiently discriminating an individual from other people. While general camera systems obtain focused images by using various gradient measures to estimate high-frequency components, mobile cameras cannot acquire recognizable images in the same way because the obtained images may not be adequate for fingerprint recognition, even if they are properly focused. A recognizable image has to meet the following two conditions: First, valid region in the recognizable image should be large enough compared with other nonrecognizable images. Here, a valid region is a well-focused part, and ridges in the region are clearly distinguishable from valleys. In order to select valid regions, this paper proposes a new focus-measurement algorithm using the secondary partial derivatives and a quality estimation utilizing the coherence and symmetry of gradient distribution. Second, rolling and pitching degrees of a finger measured from the camera plane should be within some limit for a recognizable image. The position of a core point and the contour of a finger are used to estimate the degrees of rolling and pitching. Experimental results show that our proposed method selects valid regions and estimates the degrees of rolling and pitching properly. In addition, fingerprint-verification performance is improved by detecting the recognizable images.

Gallbladder radionuclide scan (image)

MedlinePlus

... gallbladder radionuclide scan is performed by injecting a tracer (radioactive chemical) into the bloodstream. A gamma camera ... detect the gamma rays being emitted from the tracer, and the image of where the tracer is ...

A design of camera simulator for photoelectric image acquisition system

NASA Astrophysics Data System (ADS)

Cai, Guanghui; Liu, Wen; Zhang, Xin

2015-02-01

In the process of developing the photoelectric image acquisition equipment, it needs to verify the function and performance. In order to make the photoelectric device recall the image data formerly in the process of debugging and testing, a design scheme of the camera simulator is presented. In this system, with FPGA as the control core, the image data is saved in NAND flash trough USB2.0 bus. Due to the access rate of the NAND, flash is too slow to meet the requirement of the sytsem, to fix the problem, the pipeline technique and the High-Band-Buses technique are applied in the design to improve the storage rate. It reads image data out from flash in the control logic of FPGA and output separately from three different interface of Camera Link, LVDS and PAL, which can provide image data for photoelectric image acquisition equipment's debugging and algorithm validation. However, because the standard of PAL image resolution is 720*576, the resolution is different between PAL image and input image, so the image can be output after the resolution conversion. The experimental results demonstrate that the camera simulator outputs three format image sequence correctly, which can be captured and displayed by frame gather. And the three-format image data can meet test requirements of the most equipment, shorten debugging time and improve the test efficiency.

The Si/CdTe semiconductor Compton camera of the ASTRO-H Soft Gamma-ray Detector (SGD)

NASA Astrophysics Data System (ADS)

Watanabe, Shin; Tajima, Hiroyasu; Fukazawa, Yasushi; Ichinohe, Yuto; Takeda, Shin`ichiro; Enoto, Teruaki; Fukuyama, Taro; Furui, Shunya; Genba, Kei; Hagino, Kouichi; Harayama, Atsushi; Kuroda, Yoshikatsu; Matsuura, Daisuke; Nakamura, Ryo; Nakazawa, Kazuhiro; Noda, Hirofumi; Odaka, Hirokazu; Ohta, Masayuki; Onishi, Mitsunobu; Saito, Shinya; Sato, Goro; Sato, Tamotsu; Takahashi, Tadayuki; Tanaka, Takaaki; Togo, Atsushi; Tomizuka, Shinji

2014-11-01

The Soft Gamma-ray Detector (SGD) is one of the instrument payloads onboard ASTRO-H, and will cover a wide energy band (60-600 keV) at a background level 10 times better than instruments currently in orbit. The SGD achieves low background by combining a Compton camera scheme with a narrow field-of-view active shield. The Compton camera in the SGD is realized as a hybrid semiconductor detector system which consists of silicon and cadmium telluride (CdTe) sensors. The design of the SGD Compton camera has been finalized and the final prototype, which has the same configuration as the flight model, has been fabricated for performance evaluation. The Compton camera has overall dimensions of 12 cm×12 cm×12 cm, consisting of 32 layers of Si pixel sensors and 8 layers of CdTe pixel sensors surrounded by 2 layers of CdTe pixel sensors. The detection efficiency of the Compton camera reaches about 15% and 3% for 100 keV and 511 keV gamma rays, respectively. The pixel pitch of the Si and CdTe sensors is 3.2 mm, and the signals from all 13,312 pixels are processed by 208 ASICs developed for the SGD. Good energy resolution is afforded by semiconductor sensors and low noise ASICs, and the obtained energy resolutions with the prototype Si and CdTe pixel sensors are 1.0-2.0 keV (FWHM) at 60 keV and 1.6-2.5 keV (FWHM) at 122 keV, respectively. This results in good background rejection capability due to better constraints on Compton kinematics. Compton camera energy resolutions achieved with the final prototype are 6.3 keV (FWHM) at 356 keV and 10.5 keV (FWHM) at 662 keV, which satisfy the instrument requirements for the SGD Compton camera (better than 2%). Moreover, a low intrinsic background has been confirmed by the background measurement with the final prototype.

Two-modality γ detection of blood volume by camera imaging and nonimaging stethoscope for kinetic studies of cardiovascular control in nuclear medicine

NASA Astrophysics Data System (ADS)

Eclancher, Bernard; Chambron, Jacques; Dumitresco, Barbu; Karman, Miklos; Pszota, Agnes; Simon, Atilla; Didon-Poncelet, Anna; Demangeat, Jean

2002-04-01

The quantification of rapid hemodynamic reactions to wide and slow breathing movements has been performed, by two modalities (gamma) -left ventriculography of 99mTc-labeled blood volume, in anterior oblique incidence on standing and even exercising healthy volunteers and cardiac patients. A highly sensitive stethoscope delivered whole (gamma) -counts acquired at 30 msec intervals in a square field of view including the left ventricle, in a one dimensional low resolution imaging mode for beat to beat analysis. A planar 2D (gamma) -camera imaging of the same cardiac area was then performed without cardiac gating for alternate acquisitions during deep inspiration and deep expiration, completed by a 3D MRI assessment of the stethoscope detection field. Young healthy volunteers displayed wide variations of diastolic times and stroke volumes, as a result of enhanced baroreflex control, together with +/- 16% variations of the stethoscope's background blood volume counts. Any of the components of these responses were shifted, abolished or even inverted as a result of either obesity, hypertension, aging or cardiac pathologies. The assessment of breathing control of the cardiovascular system by the beat to beat (gamma) -ventriculography combined with nuclear 2D and 3D MRI imaging is a kinetic method allowing the detection of functional anomalies in still ambulatory patients.

SU-C-201-03: Coded Aperture Gamma-Ray Imaging Using Pixelated Semiconductor Detectors

DOE Office of Scientific and Technical Information (OSTI.GOV)

Joshi, S; Kaye, W; Jaworski, J

2015-06-15

Purpose: Improved localization of gamma-ray emissions from radiotracers is essential to the progress of nuclear medicine. Polaris is a portable, room-temperature operated gamma-ray imaging spectrometer composed of two 3×3 arrays of thick CdZnTe (CZT) detectors, which detect gammas between 30keV and 3MeV with energy resolution of <1% FWHM at 662keV. Compton imaging is used to map out source distributions in 4-pi space; however, is only effective above 300keV where Compton scatter is dominant. This work extends imaging to photoelectric energies (<300keV) using coded aperture imaging (CAI), which is essential for localization of Tc-99m (140keV). Methods: CAI, similar to the pinholemore » camera, relies on an attenuating mask, with open/closed elements, placed between the source and position-sensitive detectors. Partial attenuation of the source results in a “shadow” or count distribution that closely matches a portion of the mask pattern. Ideally, each source direction corresponds to a unique count distribution. Using backprojection reconstruction, the source direction is determined within the field of view. The knowledge of 3D position of interaction results in improved image quality. Results: Using a single array of detectors, a coded aperture mask, and multiple Co-57 (122keV) point sources, image reconstruction is performed in real-time, on an event-by-event basis, resulting in images with an angular resolution of ∼6 degrees. Although material nonuniformities contribute to image degradation, the superposition of images from individual detectors results in improved SNR. CAI was integrated with Compton imaging for a seamless transition between energy regimes. Conclusion: For the first time, CAI has been applied to thick, 3D position sensitive CZT detectors. Real-time, combined CAI and Compton imaging is performed using two 3×3 detector arrays, resulting in a source distribution in space. This system has been commercialized by H3D, Inc. and is being acquired

Applying and extending ISO/TC42 digital camera resolution standards to mobile imaging products

NASA Astrophysics Data System (ADS)

Williams, Don; Burns, Peter D.

2007-01-01

There are no fundamental differences between today's mobile telephone cameras and consumer digital still cameras that suggest many existing ISO imaging performance standards do not apply. To the extent that they have lenses, color filter arrays, detectors, apertures, image processing, and are hand held, there really are no operational or architectural differences. Despite this, there are currently differences in the levels of imaging performance. These are driven by physical and economic constraints, and image-capture conditions. Several ISO standards for resolution, well established for digital consumer digital cameras, require care when applied to the current generation of cell phone cameras. In particular, accommodation of optical flare, shading non-uniformity and distortion are recommended. We offer proposals for the application of existing ISO imaging resolution performance standards to mobile imaging products, and suggestions for extending performance standards to the characteristic behavior of camera phones.

Scalar wave-optical reconstruction of plenoptic camera images.

PubMed

Junker, André; Stenau, Tim; Brenner, Karl-Heinz

2014-09-01

We investigate the reconstruction of plenoptic camera images in a scalar wave-optical framework. Previous publications relating to this topic numerically simulate light propagation on the basis of ray tracing. However, due to continuing miniaturization of hardware components it can be assumed that in combination with low-aperture optical systems this technique may not be generally valid. Therefore, we study the differences between ray- and wave-optical object reconstructions of true plenoptic camera images. For this purpose we present a wave-optical reconstruction algorithm, which can be run on a regular computer. Our findings show that a wave-optical treatment is capable of increasing the detail resolution of reconstructed objects.

SU-G-IeP4-12: Performance of In-111 Coincident Gamma-Ray Counting: A Monte Carlo Simulation

DOE Office of Scientific and Technical Information (OSTI.GOV)

Pahlka, R; Kappadath, S; Mawlawi, O

2016-06-15

Purpose: The decay of In-111 results in a non-isotropic gamma-ray cascade, which is normally imaged using a gamma camera. Creating images with a gamma camera using coincident gamma-rays from In-111 has not been previously studied. Our objective was to explore the feasibility of imaging this cascade as coincidence events and to determine the optimal timing resolution and source activity using Monte Carlo simulations. Methods: GEANT4 was used to simulate the decay of the In-111 nucleus and to model the gamma camera. Each photon emission was assigned a timestamp, and the time delay and angular separation for the second gamma-ray inmore » the cascade was consistent with the known intermediate state half-life of 85ns. The gamma-rays are transported through a model of a Siemens dual head Symbia “S” gamma camera with a 5/8-inch thick crystal and medium energy collimators. A true coincident event was defined as a single 171keV gamma-ray followed by a single 245keV gamma-ray within a specified time window (or vice versa). Several source activities (ranging from 10uCi to 5mCi) with and without incorporation of background counts were then simulated. Each simulation was analyzed using varying time windows to assess random events. The noise equivalent count rate (NECR) was computed based on the number of true and random counts for each combination of activity and time window. No scatter events were assumed since sources were simulated in air. Results: As expected, increasing the timing window increased the total number of observed coincidences albeit at the expense of true coincidences. A timing window range of 200–500ns maximizes the NECR at clinically-used source activities. The background rate did not significantly alter the maximum NECR. Conclusion: This work suggests coincident measurements of In-111 gamma-ray decay can be performed with commercial gamma cameras at clinically-relevant activities. Work is ongoing to assess useful clinical applications.« less

Thermal Effects on Camera Focal Length in Messenger Star Calibration and Orbital Imaging

NASA Astrophysics Data System (ADS)

Burmeister, S.; Elgner, S.; Preusker, F.; Stark, A.; Oberst, J.

2018-04-01

We analyse images taken by the MErcury Surface, Space ENviorment, GEochemistry, and Ranging (MESSENGER) spacecraft for the camera's thermal response in the harsh thermal environment near Mercury. Specifically, we study thermally induced variations in focal length of the Mercury Dual Imaging System (MDIS). Within the several hundreds of images of star fields, the Wide Angle Camera (WAC) typically captures up to 250 stars in one frame of the panchromatic channel. We measure star positions and relate these to the known star coordinates taken from the Tycho-2 catalogue. We solve for camera pointing, the focal length parameter and two non-symmetrical distortion parameters for each image. Using data from the temperature sensors on the camera focal plane we model a linear focal length function in the form of f(T) = A0 + A1 T. Next, we use images from MESSENGER's orbital mapping mission. We deal with large image blocks, typically used for the production of a high-resolution digital terrain models (DTM). We analyzed images from the combined quadrangles H03 and H07, a selected region, covered by approx. 10,600 images, in which we identified about 83,900 tiepoints. Using bundle block adjustments, we solved for the unknown coordinates of the control points, the pointing of the camera - as well as the camera's focal length. We then fit the above linear function with respect to the focal plane temperature. As a result, we find a complex response of the camera to thermal conditions of the spacecraft. To first order, we see a linear increase by approx. 0.0107 mm per degree temperature for the Narrow-Angle Camera (NAC). This is in agreement with the observed thermal response seen in images of the panchromatic channel of the WAC. Unfortunately, further comparisons of results from the two methods, both of which use different portions of the available image data, are limited. If leaving uncorrected, these effects may pose significant difficulties in the photogrammetric analysis

3-D endoscopic imaging using plenoptic camera.

PubMed

Le, Hanh N D; Decker, Ryan; Opferman, Justin; Kim, Peter; Krieger, Axel; Kang, Jin U

2016-06-01

Three-dimensional endoscopic imaging using plenoptic technique combined with F-matching algorithm has been pursued in this study. A custom relay optics was designed to integrate a commercial surgical straight endoscope with a plenoptic camera.

SeHCAT retention values as measured with a collimated and an uncollimated gamma camera: a method comparison study.

PubMed

Wright, James W; Lovell, Lesley A; Gemmell, Howard G; McKiddie, Fergus; Staff, Roger T

2013-07-01

TauroH-23-(Se) selena-25-homocholic acid retention values are used in the diagnosis of bile acid malabsorption. The standard method for measuring values is with an uncollimated gamma camera, which can create some logistic difficulties, with other background sources of activity, which are irrelevant when a collimator is used, becoming significant. In this study we compare the retention values obtained with a collimated and an uncollimated gamma camera in phantoms and in 23 patients. Bland-Altman plots were created using the data, which showed a mean bias in retention of 0.10% in the phantom study and 0.55% in the patient study between methods. A Wilcoxon signed-rank test with the null hypothesis of zero median difference between uncollimated and collimated methods was not statistically significant to P values less than 0.05 in the patient and phantom studies. In the patient study, on using a fixed boundary of retention (10%) between positive and negative status, the status of one patient was changed from negative (12%) to positive (9%). We conclude that measurement of retention with a collimated gamma camera is similar but not identical to that of uncollimated values. The clinical significance of this shift is unclear, as the threshold of significance and the method of integrating this measure with other clinical factors into management remain unclear.

Simulation study of the second-generation MR-compatible SPECT system based on the inverted compound-eye gamma camera design

NASA Astrophysics Data System (ADS)

Lai, Xiaochun; Meng, Ling-Jian

2018-02-01

In this paper, we present simulation studies for the second-generation MRI compatible SPECT system, MRC-SPECT-II, based on an inverted compound eye (ICE) gamma camera concept. The MRC-SPECT-II system consists of a total of 1536 independent micro-pinhole-camera-elements (MCEs) distributed in a ring with an inner diameter of 6 cm. This system provides a FOV of 1 cm diameter and a peak geometrical efficiency of approximately 1.3% (the typical levels of 0.1%-0.01% found in modern pre-clinical SPECT instrumentations), while maintaining a sub-500 μm spatial resolution. Compared to the first-generation MRC-SPECT system (MRC-SPECT-I) (Cai 2014 Nucl. Instrum. Methods Phys. Res. A 734 147-51) developed in our lab, the MRC-SPECT-II system offers a similar resolution with dramatically improved sensitivity and greatly reduced physical dimension. The latter should allow the system to be placed inside most clinical and pre-clinical MRI scanners for high-performance simultaneous MRI and SPECT imaging.

An HDR imaging method with DTDI technology for push-broom cameras

NASA Astrophysics Data System (ADS)

Sun, Wu; Han, Chengshan; Xue, Xucheng; Lv, Hengyi; Shi, Junxia; Hu, Changhong; Li, Xiangzhi; Fu, Yao; Jiang, Xiaonan; Huang, Liang; Han, Hongyin

2018-03-01

Conventionally, high dynamic-range (HDR) imaging is based on taking two or more pictures of the same scene with different exposure. However, due to a high-speed relative motion between the camera and the scene, it is hard for this technique to be applied to push-broom remote sensing cameras. For the sake of HDR imaging in push-broom remote sensing applications, the present paper proposes an innovative method which can generate HDR images without redundant image sensors or optical components. Specifically, this paper adopts an area array CMOS (complementary metal oxide semiconductor) with the digital domain time-delay-integration (DTDI) technology for imaging, instead of adopting more than one row of image sensors, thereby taking more than one picture with different exposure. And then a new HDR image by fusing two original images with a simple algorithm can be achieved. By conducting the experiment, the dynamic range (DR) of the image increases by 26.02 dB. The proposed method is proved to be effective and has potential in other imaging applications where there is a relative motion between the cameras and scenes.

Design upgrades to the DIII-D gamma ray imager

NASA Astrophysics Data System (ADS)

Lvovskiy, A.; Cooper, C. M.; Eidietis, N. W.; Pace, D.; Paz-Soldan, C.

2016-10-01

Generation of runaway electrons (RE) in tokamak disruptions can cause damage of plasma facing components. RE studies are necessary in order to provide a reliable mechanism of RE mitigation. For that task a gamma ray imager (GRI) has been developed for DIII-D. It measures the bremsstrahlung emission by RE providing information on RE energy spectrum and RE distribution across a poloidal cross-section. The GRI consists of a lead pinhole camera illuminating a 2D array of 30 BGO detectors placed in the DIII-D mid-plane. First results showed the successful measurements of RE energy spectra in the range 1 - 60 MeV with time resolution 100 μs. They have been obtained in the low-flux quiescent RE regime via pulse-high analysis. The measurements in the high gamma flux post-disruption RE regime showed strong signal saturation. Here we present GRI design upgrades towards signal attenuation and better detector shielding including Monte-Carlo Neutral Particle modeling of GRI irradiation, as well as improved calibration techniques and options to improve electronic noise rejection. Work supported by US DOE under DE-AC05-06OR23100 and DE-FC02-04ER54698.

CMOS Image Sensors: Electronic Camera On A Chip

NASA Technical Reports Server (NTRS)

Fossum, E. R.

1995-01-01

Recent advancements in CMOS image sensor technology are reviewed, including both passive pixel sensors and active pixel sensors. On- chip analog to digital converters and on-chip timing and control circuits permit realization of an electronic camera-on-a-chip. Highly miniaturized imaging systems based on CMOS image sensor technology are emerging as a competitor to charge-coupled devices for low cost uses.

3-D endoscopic imaging using plenoptic camera

PubMed Central

Le, Hanh N. D.; Decker, Ryan; Opferman, Justin; Kim, Peter; Krieger, Axel

2017-01-01

Three-dimensional endoscopic imaging using plenoptic technique combined with F-matching algorithm has been pursued in this study. A custom relay optics was designed to integrate a commercial surgical straight endoscope with a plenoptic camera. PMID:29276806

Display gamma is an important factor in Web image viewing

NASA Astrophysics Data System (ADS)

Zhang, Xuemei; Lavin, Yingmei; Silverstein, D. Amnon

2001-06-01

We conducted a perceptual image preference experiment over the web to find our (1) if typical computer users have significant variations in their display gamma settings, and (2) if so, do the gamma settings have significant perceptual effect on the appearance of images in their web browsers. The digital image renderings used were found to have preferred tone characteristics from a previous lab- controlled experiment. They were rendered with 4 different gamma settings. The subjects were asked to view the images over the web, with their own computer equipment and web browsers. The subjects werewe asked to view the images over the web, with their own computer equipment and web browsers. The subjects made pair-wise subjective preference judgements on which rendering they liked bets for each image. Each subject's display gamma setting was estimated using a 'gamma estimator' tool, implemented as a Java applet. The results indicated that (1) the user's gamma settings, as estimated in the experiment, span a wide range from about 1.8 to about 3.0; (2) the subjects preferred images that werewe rendered with a 'correct' gamma value matching their display setting. Subjects disliked images rendered with a gamma value not matching their displays'. This indicates that display gamma estimation is a perceptually significant factor in web image optimization.

A comprehensive experimental characterization of the iPIX gamma imager

NASA Astrophysics Data System (ADS)

Amgarou, K.; Paradiso, V.; Patoz, A.; Bonnet, F.; Handley, J.; Couturier, P.; Becker, F.; Menaa, N.

2016-08-01

The results of more than 280 different experiments aimed at exploring the main features and performances of a newly developed gamma imager, called iPIX, are summarized in this paper. iPIX is designed to quickly localize radioactive sources while estimating the ambient dose equivalent rate at the measurement point. It integrates a 1 mm thick CdTe detector directly bump-bonded to a Timepix chip, a tungsten coded-aperture mask, and a mini RGB camera. It also represents a major technological breakthrough in terms of lightness, compactness, usability, response sensitivity, and angular resolution. As an example of its key strengths, an 241Am source with a dose rate of only few nSv/h can be localized in less than one minute.

Development of an Ultra-Violet Digital Camera for Volcanic Sulfur Dioxide Imaging

NASA Astrophysics Data System (ADS)

Bluth, G. J.; Shannon, J. M.; Watson, I. M.; Prata, F. J.; Realmuto, V. J.

2006-12-01

In an effort to improve monitoring of passive volcano degassing, we have constructed and tested a digital camera for quantifying the sulfur dioxide (SO2) content of volcanic plumes. The camera utilizes a bandpass filter to collect photons in the ultra-violet (UV) region where SO2 selectively absorbs UV light. SO2 is quantified by imaging calibration cells of known SO2 concentrations. Images of volcanic SO2 plumes were collected at four active volcanoes with persistent passive degassing: Villarrica, located in Chile, and Santiaguito, Fuego, and Pacaya, located in Guatemala. Images were collected from distances ranging between 4 and 28 km away, with crisp detection up to approximately 16 km. Camera set-up time in the field ranges from 5-10 minutes and images can be recorded in as rapidly as 10-second intervals. Variable in-plume concentrations can be observed and accurate plume speeds (or rise rates) can readily be determined by tracing individual portions of the plume within sequential images. Initial fluxes computed from camera images require a correction for the effects of environmental light scattered into the field of view. At Fuego volcano, simultaneous measurements of corrected SO2 fluxes with the camera and a Correlation Spectrometer (COSPEC) agreed within 25 percent. Experiments at the other sites were equally encouraging, and demonstrated the camera's ability to detect SO2 under demanding meteorological conditions. This early work has shown great success in imaging SO2 plumes and offers promise for volcano monitoring due to its rapid deployment and data processing capabilities, relatively low cost, and improved interpretation afforded by synoptic plume coverage from a range of distances.

Image quality evaluation of color displays using a Fovean color camera

NASA Astrophysics Data System (ADS)

Roehrig, Hans; Dallas, William J.; Fan, Jiahua; Krupinski, Elizabeth A.; Redford, Gary R.; Yoneda, Takahiro

2007-03-01

This paper presents preliminary data on the use of a color camera for the evaluation of Quality Control (QC) and Quality Analysis (QA) of a color LCD in comparison with that of a monochrome LCD. The color camera is a C-MOS camera with a pixel size of 9 µm and a pixel matrix of 2268 × 1512 × 3. The camera uses a sensor that has co-located pixels for all three primary colors. The imaging geometry used mostly was 12 × 12 camera pixels per display pixel even though it appears that an imaging geometry of 17.6 might provide results which are more accurate. The color camera is used as an imaging colorimeter, where each camera pixel is calibrated to serve as a colorimeter. This capability permits the camera to determine chromaticity of the color LCD at different sections of the display. After the color calibration with a CS-200 colorimeter the color coordinates of the display's primaries determined from the camera's luminance response are very close to those found from the CS-200. Only the color coordinates of the display's white point were in error. Modulation Transfer Function (MTF) as well as Noise in terms of the Noise Power Spectrum (NPS) of both LCDs were evaluated. The horizontal MTFs of both displays have a larger negative slope than the vertical MTFs, indicating that the horizontal MTFs are poorer than the vertical MTFs. However the modulations at the Nyquist frequency seem lower for the color LCD than for the monochrome LCD. These results contradict simulations regarding MTFs in the vertical direction. The spatial noise of the color display in both directions are larger than that of the monochrome display. Attempts were also made to analyze the total noise in terms of spatial and temporal noise by applying subtractions of images taken at exactly the same exposure. Temporal noise seems to be significantly lower than spatial noise.

A new gamma ray imaging diagnostic for runaway electron studies at DIII-D

NASA Astrophysics Data System (ADS)

Cooper, C. M.; Pace, D. C.; Eidietis, N. W.; Paz-Soldan, C.; Commaux, N.; Shiraki, D.; Hollmann, E. M.; Moyer, R. A.; Risov, V.

2015-11-01

A new Gamma Ray Imager (GRI) is developed to probe the electron distribution function with 2D spatial resolution during runaway electron (RE) experiments at DIII-D. The diagnostic is sensitive to 0.5 - 50 MeV gamma rays, allowing characterization of the RE distribution function evolution during RE dissipation from pellet injection. The GRI consists of a lead ``pinhole camera'' mounted on the midplane with 11x11 counter-current tangential chords 20 cm wide that span the vessel. Up to 30 bismuth germanate (BGO) scintillation detectors capture RE Bremsstrahlung radiation. Detectors operate in current saturation mode at 10 MHz, or the flux is attenuated for Pulse Height Analysis (PHA) capable of discriminating up to ~10k pulses per second. Digital signal processing routines combining shaping filters are performed during PHA to reject noise and record gamma ray energy. The GRI setup and PHA algorithms will be described and initial data from experiments will be presented. Work supported by the US DOE under DE-AC05-00OR22725, DE-FG02-07ER54917 & DE-FC02-04ER54698.

TIRCAM2: The TIFR near infrared imaging camera

NASA Astrophysics Data System (ADS)

Naik, M. B.; Ojha, D. K.; Ghosh, S. K.; Poojary, S. S.; Jadhav, R. B.; Meshram, G. S.; Sandimani, P. R.; Bhagat, S. B.; D'Costa, S. L. A.; Gharat, S. M.; Bakalkar, C. B.; Ninan, J. P.; Joshi, J. S.

2012-12-01

TIRCAM2 (TIFR near infrared imaging camera - II) is a closed cycle cooled imager that has been developed by the Infrared Astronomy Group at the Tata Institute of Fundamental Research for observations in the near infrared band of 1 to 3.7 μm with existing Indian telescopes. In this paper, we describe some of the technical details of TIRCAM2 and report its observing capabilities, measured performance and limiting magnitudes with the 2-m IUCAA Girawali telescope and the 1.2-m PRL Gurushikhar telescope. The main highlight is the camera's capability of observing in the nbL (3.59 mum) band enabling our primary motivation of mapping of Polycyclic Aromatic Hydrocarbon (PAH) emission at 3.3 mum.

Coincidence electron/ion imaging with a fast frame camera

NASA Astrophysics Data System (ADS)

Li, Wen; Lee, Suk Kyoung; Lin, Yun Fei; Lingenfelter, Steven; Winney, Alexander; Fan, Lin

2015-05-01

A new time- and position- sensitive particle detection system based on a fast frame CMOS camera is developed for coincidence electron/ion imaging. The system is composed of three major components: a conventional microchannel plate (MCP)/phosphor screen electron/ion imager, a fast frame CMOS camera and a high-speed digitizer. The system collects the positional information of ions/electrons from a fast frame camera through real-time centroiding while the arrival times are obtained from the timing signal of MCPs processed by a high-speed digitizer. Multi-hit capability is achieved by correlating the intensity of electron/ion spots on each camera frame with the peak heights on the corresponding time-of-flight spectrum. Efficient computer algorithms are developed to process camera frames and digitizer traces in real-time at 1 kHz laser repetition rate. We demonstrate the capability of this system by detecting a momentum-matched co-fragments pair (methyl and iodine cations) produced from strong field dissociative double ionization of methyl iodide. We further show that a time resolution of 30 ps can be achieved when measuring electron TOF spectrum and this enables the new system to achieve a good energy resolution along the TOF axis.

Prompt Gamma Imaging for In Vivo Range Verification of Pencil Beam Scanning Proton Therapy.

PubMed

Xie, Yunhe; Bentefour, El Hassane; Janssens, Guillaume; Smeets, Julien; Vander Stappen, François; Hotoiu, Lucian; Yin, Lingshu; Dolney, Derek; Avery, Stephen; O'Grady, Fionnbarr; Prieels, Damien; McDonough, James; Solberg, Timothy D; Lustig, Robert A; Lin, Alexander; Teo, Boon-Keng K

2017-09-01

To report the first clinical results and value assessment of prompt gamma imaging for in vivo proton range verification in pencil beam scanning mode. A stand-alone, trolley-mounted, prototype prompt gamma camera utilizing a knife-edge slit collimator design was used to record the prompt gamma signal emitted along the proton tracks during delivery of proton therapy for a brain cancer patient. The recorded prompt gamma depth detection profiles of individual pencil beam spots were compared with the expected profiles simulated from the treatment plan. In 6 treatment fractions recorded over 3 weeks, the mean (± standard deviation) range shifts aggregated over all spots in 9 energy layers were -0.8 ± 1.3 mm for the lateral field, 1.7 ± 0.7 mm for the right-superior-oblique field, and -0.4 ± 0.9 mm for the vertex field. This study demonstrates the feasibility and illustrates the distinctive benefits of prompt gamma imaging in pencil beam scanning treatment mode. Accuracy in range verification was found in this first clinical case to be better than the range uncertainty margin applied in the treatment plan. These first results lay the foundation for additional work toward tighter integration of the system for in vivo proton range verification and quantification of range uncertainties. Copyright © 2017 Elsevier Inc. All rights reserved.

Implicit multiplane 3D camera calibration matrices for stereo image processing

NASA Astrophysics Data System (ADS)

McKee, James W.; Burgett, Sherrie J.

1997-12-01

By implicit camera calibration, we mean the process of calibrating cameras without explicitly computing their physical parameters. We introduce a new implicit model based on a generalized mapping between an image plane and multiple, parallel calibration planes (usually between four to seven planes). This paper presents a method of computing a relationship between a point on a three-dimensional (3D) object and its corresponding two-dimensional (2D) coordinate in a camera image. This relationship is expanded to form a mapping of points in 3D space to points in image (camera) space and visa versa that requires only matrix multiplication operations. This paper presents the rationale behind the selection of the forms of four matrices and the algorithms to calculate the parameters for the matrices. Two of the matrices are used to map 3D points in object space to 2D points on the CCD camera image plane. The other two matrices are used to map 2D points on the image plane to points on user defined planes in 3D object space. The mappings include compensation for lens distortion and measurement errors. The number of parameters used can be increased, in a straight forward fashion, to calculate and use as many parameters as needed to obtain a user desired accuracy. Previous methods of camera calibration use a fixed number of parameters which can limit the obtainable accuracy and most require the solution of nonlinear equations. The procedure presented can be used to calibrate a single camera to make 2D measurements or calibrate stereo cameras to make 3D measurements. Positional accuracy of better than 3 parts in 10,000 have been achieved. The algorithms in this paper were developed and are implemented in MATLABR (registered trademark of The Math Works, Inc.). We have developed a system to analyze the path of optical fiber during high speed payout (unwinding) of optical fiber off a bobbin. This requires recording and analyzing high speed (5 microsecond exposure time

Image Intensifier Modules For Use With Commercially Available Solid State Cameras

NASA Astrophysics Data System (ADS)

Murphy, Howard; Tyler, Al; Lake, Donald W.

1989-04-01

A modular approach to design has contributed greatly to the success of the family of machine vision video equipment produced by EG&G Reticon during the past several years. Internal modularity allows high-performance area (matrix) and line scan cameras to be assembled with two or three electronic subassemblies with very low labor costs, and permits camera control and interface circuitry to be realized by assemblages of various modules suiting the needs of specific applications. Product modularity benefits equipment users in several ways. Modular matrix and line scan cameras are available in identical enclosures (Fig. 1), which allows enclosure components to be purchased in volume for economies of scale and allows field replacement or exchange of cameras within a customer-designed system to be easily accomplished. The cameras are optically aligned (boresighted) at final test; modularity permits optical adjustments to be made with the same precise test equipment for all camera varieties. The modular cameras contain two, or sometimes three, hybrid microelectronic packages (Fig. 2). These rugged and reliable "submodules" perform all of the electronic operations internal to the camera except for the job of image acquisition performed by the monolithic image sensor. Heat produced by electrical power dissipation in the electronic modules is conducted through low resistance paths to the camera case by the metal plates, which results in a thermally efficient and environmentally tolerant camera with low manufacturing costs. A modular approach has also been followed in design of the camera control, video processor, and computer interface accessory called the Formatter (Fig. 3). This unit can be attached directly onto either a line scan or matrix modular camera to form a self-contained units, or connected via a cable to retain the advantages inherent to a small, light weight, and rugged image sensing component. Available modules permit the bus-structured Formatter to be

Brute Force Matching Between Camera Shots and Synthetic Images from Point Clouds

NASA Astrophysics Data System (ADS)

Boerner, R.; Kröhnert, M.

2016-06-01

3D point clouds, acquired by state-of-the-art terrestrial laser scanning techniques (TLS), provide spatial information about accuracies up to several millimetres. Unfortunately, common TLS data has no spectral information about the covered scene. However, the matching of TLS data with images is important for monoplotting purposes and point cloud colouration. Well-established methods solve this issue by matching of close range images and point cloud data by fitting optical camera systems on top of laser scanners or rather using ground control points. The approach addressed in this paper aims for the matching of 2D image and 3D point cloud data from a freely moving camera within an environment covered by a large 3D point cloud, e.g. a 3D city model. The key advantage of the free movement affects augmented reality applications or real time measurements. Therefore, a so-called real image, captured by a smartphone camera, has to be matched with a so-called synthetic image which consists of reverse projected 3D point cloud data to a synthetic projection centre whose exterior orientation parameters match the parameters of the image, assuming an ideal distortion free camera.

A combined microphone and camera calibration technique with application to acoustic imaging.

PubMed

Legg, Mathew; Bradley, Stuart

2013-10-01

We present a calibration technique for an acoustic imaging microphone array, combined with a digital camera. Computer vision and acoustic time of arrival data are used to obtain microphone coordinates in the camera reference frame. Our new method allows acoustic maps to be plotted onto the camera images without the need for additional camera alignment or calibration. Microphones and cameras may be placed in an ad-hoc arrangement and, after calibration, the coordinates of the microphones are known in the reference frame of a camera in the array. No prior knowledge of microphone positions, inter-microphone spacings, or air temperature is required. This technique is applied to a spherical microphone array and a mean difference of 3 mm was obtained between the coordinates obtained with this calibration technique and those measured using a precision mechanical method.

Method used to test the imaging consistency of binocular camera's left-right optical system

NASA Astrophysics Data System (ADS)

Liu, Meiying; Wang, Hu; Liu, Jie; Xue, Yaoke; Yang, Shaodong; Zhao, Hui

2016-09-01

To binocular camera, the consistency of optical parameters of the left and the right optical system is an important factor that will influence the overall imaging consistency. In conventional testing procedure of optical system, there lacks specifications suitable for evaluating imaging consistency. In this paper, considering the special requirements of binocular optical imaging system, a method used to measure the imaging consistency of binocular camera is presented. Based on this method, a measurement system which is composed of an integrating sphere, a rotary table and a CMOS camera has been established. First, let the left and the right optical system capture images in normal exposure time under the same condition. Second, a contour image is obtained based on the multiple threshold segmentation result and the boundary is determined using the slope of contour lines near the pseudo-contour line. Third, the constraint of gray level based on the corresponding coordinates of left-right images is established and the imaging consistency could be evaluated through standard deviation σ of the imaging grayscale difference D (x, y) between the left and right optical system. The experiments demonstrate that the method is suitable for carrying out the imaging consistency testing for binocular camera. When the standard deviation 3σ distribution of imaging gray difference D (x, y) between the left and right optical system of the binocular camera does not exceed 5%, it is believed that the design requirements have been achieved. This method could be used effectively and paves the way for the imaging consistency testing of the binocular camera.

SPECT detectors: the Anger Camera and beyond

PubMed Central

Peterson, Todd E.; Furenlid, Lars R.

2011-01-01

The development of radiation detectors capable of delivering spatial information about gamma-ray interactions was one of the key enabling technologies for nuclear medicine imaging and, eventually, single-photon emission computed tomography (SPECT). The continuous NaI(Tl) scintillator crystal coupled to an array of photomultiplier tubes, almost universally referred to as the Anger Camera after its inventor, has long been the dominant SPECT detector system. Nevertheless, many alternative materials and configurations have been investigated over the years. Technological advances as well as the emerging importance of specialized applications, such as cardiac and preclinical imaging, have spurred innovation such that alternatives to the Anger Camera are now part of commercial imaging systems. Increased computing power has made it practical to apply advanced signal processing and estimation schemes to make better use of the information contained in the detector signals. In this review we discuss the key performance properties of SPECT detectors and survey developments in both scintillator and semiconductor detectors and their readouts with an eye toward some of the practical issues at least in part responsible for the continuing prevalence of the Anger Camera in the clinic. PMID:21828904

Convolutional Neural Network-Based Shadow Detection in Images Using Visible Light Camera Sensor.

PubMed

Kim, Dong Seop; Arsalan, Muhammad; Park, Kang Ryoung

2018-03-23

Recent developments in intelligence surveillance camera systems have enabled more research on the detection, tracking, and recognition of humans. Such systems typically use visible light cameras and images, in which shadows make it difficult to detect and recognize the exact human area. Near-infrared (NIR) light cameras and thermal cameras are used to mitigate this problem. However, such instruments require a separate NIR illuminator, or are prohibitively expensive. Existing research on shadow detection in images captured by visible light cameras have utilized object and shadow color features for detection. Unfortunately, various environmental factors such as illumination change and brightness of background cause detection to be a difficult task. To overcome this problem, we propose a convolutional neural network-based shadow detection method. Experimental results with a database built from various outdoor surveillance camera environments, and from the context-aware vision using image-based active recognition (CAVIAR) open database, show that our method outperforms previous works.

Convolutional Neural Network-Based Shadow Detection in Images Using Visible Light Camera Sensor

PubMed Central

Kim, Dong Seop; Arsalan, Muhammad; Park, Kang Ryoung

2018-01-01

Recent developments in intelligence surveillance camera systems have enabled more research on the detection, tracking, and recognition of humans. Such systems typically use visible light cameras and images, in which shadows make it difficult to detect and recognize the exact human area. Near-infrared (NIR) light cameras and thermal cameras are used to mitigate this problem. However, such instruments require a separate NIR illuminator, or are prohibitively expensive. Existing research on shadow detection in images captured by visible light cameras have utilized object and shadow color features for detection. Unfortunately, various environmental factors such as illumination change and brightness of background cause detection to be a difficult task. To overcome this problem, we propose a convolutional neural network-based shadow detection method. Experimental results with a database built from various outdoor surveillance camera environments, and from the context-aware vision using image-based active recognition (CAVIAR) open database, show that our method outperforms previous works. PMID:29570690

Cameras and settings for optimal image capture from UAVs

NASA Astrophysics Data System (ADS)

Smith, Mike; O'Connor, James; James, Mike R.

2017-04-01

Aerial image capture has become very common within the geosciences due to the increasing affordability of low payload (<20 kg) Unmanned Aerial Vehicles (UAVs) for consumer markets. Their application to surveying has led to many studies being undertaken using UAV imagery captured from consumer grade cameras as primary data sources. However, image quality and the principles of image capture are seldom given rigorous discussion which can lead to experiments being difficult to accurately reproduce. In this contribution we revisit the underpinning concepts behind image capture, from which the requirements for acquiring sharp, well exposed and suitable imagery are derived. This then leads to discussion of how to optimise the platform, camera, lens and imaging settings relevant to image quality planning, presenting some worked examples as a guide. Finally, we challenge the community to make their image data open for review in order to ensure confidence in the outputs/error estimates, allow reproducibility of the results and have these comparable with future studies. We recommend providing open access imagery where possible, a range of example images, and detailed metadata to rigorously describe the image capture process.

Tenth Anniversary Image from Camera on NASA Mars Orbiter

NASA Image and Video Library

2012-02-29

NASA Mars Odyssey spacecraft captured this image on Feb. 19, 2012, 10 years to the day after the camera recorded its first view of Mars. This image covers an area in the Nepenthes Mensae region north of the Martian equator.

A compact neutron scatter camera for field deployment

DOE PAGES

Goldsmith, John E. M.; Gerling, Mark D.; Brennan, James S.

2016-08-23

Here, we describe a very compact (0.9 m high, 0.4 m diameter, 40 kg) battery operable neutron scatter camera designed for field deployment. Unlike most other systems, the configuration of the sixteen liquid-scintillator detection cells are arranged to provide omnidirectional (4π) imaging with sensitivity comparable to a conventional two-plane system. Although designed primarily to operate as a neutron scatter camera for localizing energetic neutron sources, it also functions as a Compton camera for localizing gamma sources. In addition to describing the radionuclide source localization capabilities of this system, we demonstrate how it provides neutron spectra that can distinguish plutonium metalmore » from plutonium oxide sources, in addition to the easier task of distinguishing AmBe from fission sources.« less

Concept of a photon-counting camera based on a diffraction-addressed Gray-code mask

NASA Astrophysics Data System (ADS)

Morel, Sébastien

2004-09-01

A new concept of photon counting camera for fast and low-light-level imaging applications is introduced. The possible spectrum covered by this camera ranges from visible light to gamma rays, depending on the device used to transform an incoming photon into a burst of visible photons (photo-event spot) localized in an (x,y) image plane. It is actually an evolution of the existing "PAPA" (Precision Analog Photon Address) Camera that was designed for visible photons. This improvement comes from a simplified optics. The new camera transforms, by diffraction, each photo-event spot from an image intensifier or a scintillator into a cross-shaped pattern, which is projected onto a specific Gray code mask. The photo-event position is then extracted from the signal given by an array of avalanche photodiodes (or photomultiplier tubes, alternatively) downstream of the mask. After a detailed explanation of this camera concept that we have called "DIAMICON" (DIffraction Addressed Mask ICONographer), we briefly discuss about technical solutions to build such a camera.

Spectroscopic CZT detectors development for x- and gamma-ray imaging instruments

NASA Astrophysics Data System (ADS)

Quadrini, Egidio M.; Uslenghi, Michela; Alderighi, Monica; Casini, Fabio; D'Angelo, Sergio; Fiorini, Mauro; La Palombara, Nicola; Mancini, Marcello; Monti, Serena; Bazzano, Angela; Di Cosimo, Sergio; Frutti, Massimo; Natalucci, Lorenzo; Ubertini, Pietro; Guadalupi, Giuseppe M.; Sassi, Matteo; Negri, Barbara

2007-09-01

In the context of R&D studies financed by the Italian Space Agency (ASI), a feasibility study to evaluate the Italian Industry interest in medium-large scale production of enhanced CZT detectors has been performed by an Italian Consortium. The R&D investment aims at providing in-house source of high quality solid state spectrometers for Space Astrophysics applications. As a possible spin-off industrial applications to Gamma-ray devices for non-destructive inspections in medical, commercial and security fields have been considered by ASI. The short term programme mainly consists of developing proprietary procedures for 2-3" CZT crystals growth, including bonding and contact philosophy, and a newly designed low-power electronics readout chain. The prototype design and breadboarding is based on a fast signal AD conversion with the target in order to perform a new run for an already existing low-power (<0.7 mW/pixel) ASIC. The prototype also provides digital photon energy reconstruction with particular care for multiple events and polarimetry evaluations. Scientific requirement evaluations for Space Astrophysics Satellite applications have been carried out in parallel, targeted to contribute to the ESA Cosmic Vision 2015-2025 Announcement of Opportunity. Detailed accommodation studies are undergoing, as part of this programme, to size a "Large area arcsecond angular resolution Imager" for the Gamma Ray Imager satellite (Knödlseder et al., this conference).and a new Gamma-ray Wide Field Camera for the "EDGE" proposal (Piro et al., this conference). Finally, an extended market study for cost analysis evaluation in view of the foreseen massive detector production has been performed.

Sub-Camera Calibration of a Penta-Camera

NASA Astrophysics Data System (ADS)

Jacobsen, K.; Gerke, M.

2016-03-01

Penta cameras consisting of a nadir and four inclined cameras are becoming more and more popular, having the advantage of imaging also facades in built up areas from four directions. Such system cameras require a boresight calibration of the geometric relation of the cameras to each other, but also a calibration of the sub-cameras. Based on data sets of the ISPRS/EuroSDR benchmark for multi platform photogrammetry the inner orientation of the used IGI Penta DigiCAM has been analyzed. The required image coordinates of the blocks Dortmund and Zeche Zollern have been determined by Pix4Dmapper and have been independently adjusted and analyzed by program system BLUH. With 4.1 million image points in 314 images respectively 3.9 million image points in 248 images a dense matching was provided by Pix4Dmapper. With up to 19 respectively 29 images per object point the images are well connected, nevertheless the high number of images per object point are concentrated to the block centres while the inclined images outside the block centre are satisfying but not very strongly connected. This leads to very high values for the Student test (T-test) of the finally used additional parameters or in other words, additional parameters are highly significant. The estimated radial symmetric distortion of the nadir sub-camera corresponds to the laboratory calibration of IGI, but there are still radial symmetric distortions also for the inclined cameras with a size exceeding 5μm even if mentioned as negligible based on the laboratory calibration. Radial and tangential effects of the image corners are limited but still available. Remarkable angular affine systematic image errors can be seen especially in the block Zeche Zollern. Such deformations are unusual for digital matrix cameras, but it can be caused by the correlation between inner and exterior orientation if only parallel flight lines are used. With exception of the angular affinity the systematic image errors for corresponding

Goal-oriented rectification of camera-based document images.

PubMed

Stamatopoulos, Nikolaos; Gatos, Basilis; Pratikakis, Ioannis; Perantonis, Stavros J

2011-04-01

Document digitization with either flatbed scanners or camera-based systems results in document images which often suffer from warping and perspective distortions that deteriorate the performance of current OCR approaches. In this paper, we present a goal-oriented rectification methodology to compensate for undesirable document image distortions aiming to improve the OCR result. Our approach relies upon a coarse-to-fine strategy. First, a coarse rectification is accomplished with the aid of a computationally low cost transformation which addresses the projection of a curved surface to a 2-D rectangular area. The projection of the curved surface on the plane is guided only by the textual content's appearance in the document image while incorporating a transformation which does not depend on specific model primitives or camera setup parameters. Second, pose normalization is applied on the word level aiming to restore all the local distortions of the document image. Experimental results on various document images with a variety of distortions demonstrate the robustness and effectiveness of the proposed rectification methodology using a consistent evaluation methodology that encounters OCR accuracy and a newly introduced measure using a semi-automatic procedure.

NGEE Arctic Zero Power Warming PhenoCamera Images, Barrow, Alaska, 2016

DOE Data Explorer

Shawn Serbin; Andrew McMahon; Keith Lewin; Kim Ely; Alistair Rogers

2016-11-14

StarDot NetCam SC pheno camera images collected from the top of the Barrow, BEO Sled Shed. The camera was installed to monitor the BNL TEST group's prototype ZPW (Zero Power Warming) chambers during the growing season of 2016 (including early spring and late fall). Images were uploaded to the BNL FTP server every 10 minutes and renamed with the date and time of the image. See associated data "Zero Power Warming (ZPW) Chamber Prototype Measurements, Barrow, Alaska, 2016" http://dx.doi.org/10.5440/1343066.

Feasibility of SPECT myocardial perfusion imaging in the super-obese using a multi-head semiconductor camera with attenuation correction.

PubMed

DeCicco, Anthony E; Sokil, Alexis B; Marhefka, Gregary D; Reist, Kirk; Hansen, Christopher L

2015-04-01

Obesity is not only associated with an increased risk of coronary artery disease, but also decreases the accuracy of many diagnostic modalities pertinent to this disease. Advances in myocardial perfusion imaging (MPI) have mitigated somewhat the effects of obesity, although the feasibility of MPI in the super-obese (defined as a BMI > 50) is currently untested. We undertook this study to assess the practicality of MPI in the super-obese using a multi-headed solid-state gamma camera with attenuation correction. We retrospectively identified consecutive super-obese patients referred for MPI at our institution. The images were interpreted by 3 blinded, experienced readers and graded for quality and diagnosis, and subjectively evaluated the contribution of attenuation correction. Clinical follow-up was obtained from review of medical records. 72 consecutive super-obese patients were included. Their BMI ranged from 50 to 67 (55.7 ± 5.1). Stress image quality was considered good or excellent in 45 (63%), satisfactory in 24 (33%), poor in 3 (4%), and uninterpretable in 0 patients. Rest images were considered good or excellent in 34 (49%), satisfactory in 23 (33%), poor in 13 (19%), and uninterpretable in 0 patients. Attenuation correction changed the interpretation in 34 (47%) of studies. MPI is feasible and provides acceptable image quality for super-obese patients, although it may be camera and protocol dependent.

The advantages of using a Lucky Imaging camera for observations of microlensing events

NASA Astrophysics Data System (ADS)

Sajadian, Sedighe; Rahvar, Sohrab; Dominik, Martin; Hundertmark, Markus

2016-05-01

In this work, we study the advantages of using a Lucky Imaging camera for the observations of potential planetary microlensing events. Our aim is to reduce the blending effect and enhance exoplanet signals in binary lensing systems composed of an exoplanet and the corresponding parent star. We simulate planetary microlensing light curves based on present microlensing surveys and follow-up telescopes where one of them is equipped with a Lucky Imaging camera. This camera is used at the Danish 1.54-m follow-up telescope. Using a specific observational strategy, for an Earth-mass planet in the resonance regime, where the detection probability in crowded fields is smaller, Lucky Imaging observations improve the detection efficiency which reaches 2 per cent. Given the difficulty of detecting the signal of an Earth-mass planet in crowded-field imaging even in the resonance regime with conventional cameras, we show that Lucky Imaging can substantially improve the detection efficiency.

Dual-head gamma camera system for intraoperative localization of radioactive seeds

NASA Astrophysics Data System (ADS)

Arsenali, B.; de Jong, H. W. A. M.; Viergever, M. A.; Dickerscheid, D. B. M.; Beijst, C.; Gilhuijs, K. G. A.

2015-10-01

Breast-conserving surgery is a standard option for the treatment of patients with early-stage breast cancer. This form of surgery may result in incomplete excision of the tumor. Iodine-125 labeled titanium seeds are currently used in clinical practice to reduce the number of incomplete excisions. It seems likely that the number of incomplete excisions can be reduced even further if intraoperative information about the location of the radioactive seed is combined with preoperative information about the extent of the tumor. This can be combined if the location of the radioactive seed is established in a world coordinate system that can be linked to the (preoperative) image coordinate system. With this in mind, we propose a radioactive seed localization system which is composed of two static ceiling-suspended gamma camera heads and two parallel-hole collimators. Physical experiments and computer simulations which mimic realistic clinical situations were performed to estimate the localization accuracy (defined as trueness and precision) of the proposed system with respect to collimator-source distance (ranging between 50 cm and 100 cm) and imaging time (ranging between 1 s and 10 s). The goal of the study was to determine whether or not a trueness of 5 mm can be achieved if a collimator-source distance of 50 cm and imaging time of 5 s are used (these specifications were defined by a group of dedicated breast cancer surgeons). The results from the experiments indicate that the location of the radioactive seed can be established with an accuracy of 1.6 mm  ±  0.6 mm if a collimator-source distance of 50 cm and imaging time of 5 s are used (these experiments were performed with a 4.5 cm thick block phantom). Furthermore, the results from the simulations indicate that a trueness of 3.2 mm or less can be achieved if a collimator-source distance of 50 cm and imaging time of 5 s are used (this trueness was achieved for all 14 breast phantoms which

Imaging spectrometer/camera having convex grating

NASA Technical Reports Server (NTRS)

Reininger, Francis M. (Inventor)

2000-01-01

An imaging spectrometer has fore-optics coupled to a spectral resolving system with an entrance slit extending in a first direction at an imaging location of the fore-optics for receiving the image, a convex diffraction grating for separating the image into a plurality of spectra of predetermined wavelength ranges; a spectrometer array for detecting the spectra; and at least one concave sperical mirror concentric with the diffraction grating for relaying the image from the entrance slit to the diffraction grating and from the diffraction grating to the spectrometer array. In one embodiment, the spectrometer is configured in a lateral mode in which the entrance slit and the spectrometer array are displaced laterally on opposite sides of the diffraction grating in a second direction substantially perpendicular to the first direction. In another embodiment, the spectrometer is combined with a polychromatic imaging camera array disposed adjacent said entrance slit for recording said image.

A Fast Visible Camera Divertor-Imaging Diagnostic on DIII-D

DOE Office of Scientific and Technical Information (OSTI.GOV)

Roquemore, A; Maingi, R; Lasnier, C

2007-06-19

In recent campaigns, the Photron Ultima SE fast framing camera has proven to be a powerful diagnostic when applied to imaging divertor phenomena on the National Spherical Torus Experiment (NSTX). Active areas of NSTX divertor research addressed with the fast camera include identification of types of EDGE Localized Modes (ELMs)[1], dust migration, impurity behavior and a number of phenomena related to turbulence. To compare such edge and divertor phenomena in low and high aspect ratio plasmas, a multi-institutional collaboration was developed for fast visible imaging on NSTX and DIII-D. More specifically, the collaboration was proposed to compare the NSTX smallmore » type V ELM regime [2] and the residual ELMs observed during Type I ELM suppression with external magnetic perturbations on DIII-D[3]. As part of the collaboration effort, the Photron camera was installed recently on DIII-D with a tangential view similar to the view implemented on NSTX, enabling a direct comparison between the two machines. The rapid implementation was facilitated by utilization of the existing optics that coupled the visible spectral output from the divertor vacuum ultraviolet UVTV system, which has a view similar to the view developed for the divertor tangential TV camera [4]. A remote controlled filter wheel was implemented, as was the radiation shield required for the DIII-D installation. The installation and initial operation of the camera are described in this paper, and the first images from the DIII-D divertor are presented.« less

Enhancement of low light level images using color-plus-mono dual camera.

PubMed

Jung, Yong Ju

2017-05-15

In digital photography, the improvement of imaging quality in low light shooting is one of the users' needs. Unfortunately, conventional smartphone cameras that use a single, small image sensor cannot provide satisfactory quality in low light level images. A color-plus-mono dual camera that consists of two horizontally separate image sensors, which simultaneously captures both a color and mono image pair of the same scene, could be useful for improving the quality of low light level images. However, an incorrect image fusion between the color and mono image pair could also have negative effects, such as the introduction of severe visual artifacts in the fused images. This paper proposes a selective image fusion technique that applies an adaptive guided filter-based denoising and selective detail transfer to only those pixels deemed reliable with respect to binocular image fusion. We employ a dissimilarity measure and binocular just-noticeable-difference (BJND) analysis to identify unreliable pixels that are likely to cause visual artifacts during image fusion via joint color image denoising and detail transfer from the mono image. By constructing an experimental system of color-plus-mono camera, we demonstrate that the BJND-aware denoising and selective detail transfer is helpful in improving the image quality during low light shooting.

Automatic fog detection for public safety by using camera images

NASA Astrophysics Data System (ADS)

Pagani, Giuliano Andrea; Roth, Martin; Wauben, Wiel

2017-04-01

Fog and reduced visibility have considerable impact on the performance of road, maritime, and aeronautical transportation networks. The impact ranges from minor delays to more serious congestions or unavailability of the infrastructure and can even lead to damage or loss of lives. Visibility is traditionally measured manually by meteorological observers using landmarks at known distances in the vicinity of the observation site. Nowadays, distributed cameras facilitate inspection of more locations from one remote monitoring center. The main idea is, however, still deriving the visibility or presence of fog by an operator judging the scenery and the presence of landmarks. Visibility sensors are also used, but they are rather costly and require regular maintenance. Moreover, observers, and in particular sensors, give only visibility information that is representative for a limited area. Hence the current density of visibility observations is insufficient to give detailed information on the presence of fog. Cameras are more and more deployed for surveillance and security reasons in cities and for monitoring traffic along main transportation ways. In addition to this primary use of cameras, we consider cameras as potential sensors to automatically identify low visibility conditions. The approach that we follow is to use machine learning techniques to determine the presence of fog and/or to make an estimation of the visibility. For that purpose a set of features are extracted from the camera images such as the number of edges, brightness, transmission of the image dark channel, fractal dimension. In addition to these image features, we also consider meteorological variables such as wind speed, temperature, relative humidity, and dew point as additional features to feed the machine learning model. The results obtained with a training and evaluation set consisting of 10-minute sampled images for two KNMI locations over a period of 1.5 years by using decision trees methods

Compression of CCD raw images for digital still cameras

NASA Astrophysics Data System (ADS)

Sriram, Parthasarathy; Sudharsanan, Subramania

2005-03-01

Lossless compression of raw CCD images captured using color filter arrays has several benefits. The benefits include improved storage capacity, reduced memory bandwidth, and lower power consumption for digital still camera processors. The paper discusses the benefits in detail and proposes the use of a computationally efficient block adaptive scheme for lossless compression. Experimental results are provided that indicate that the scheme performs well for CCD raw images attaining compression factors of more than two. The block adaptive method also compares favorably with JPEG-LS. A discussion is provided indicating how the proposed lossless coding scheme can be incorporated into digital still camera processors enabling lower memory bandwidth and storage requirements.

Imaging simulation of active EO-camera

NASA Astrophysics Data System (ADS)

Pérez, José; Repasi, Endre

2018-04-01

A modeling scheme for active imaging through atmospheric turbulence is presented. The model consists of two parts: In the first part, the illumination laser beam is propagated to a target that is described by its reflectance properties, using the well-known split-step Fourier method for wave propagation. In the second part, the reflected intensity distribution imaged on a camera is computed using an empirical model developed for passive imaging through atmospheric turbulence. The split-step Fourier method requires carefully chosen simulation parameters. These simulation requirements together with the need to produce dynamic scenes with a large number of frames led us to implement the model on GPU. Validation of this implementation is shown for two different metrics. This model is well suited for Gated-Viewing applications. Examples of imaging simulation results are presented here.

Pulsed-neutron imaging by a high-speed camera and center-of-gravity processing

NASA Astrophysics Data System (ADS)

Mochiki, K.; Uragaki, T.; Koide, J.; Kushima, Y.; Kawarabayashi, J.; Taketani, A.; Otake, Y.; Matsumoto, Y.; Su, Y.; Hiroi, K.; Shinohara, T.; Kai, T.

2018-01-01

Pulsed-neutron imaging is attractive technique in the research fields of energy-resolved neutron radiography and RANS (RIKEN) and RADEN (J-PARC/JAEA) are small and large accelerator-driven pulsed-neutron facilities for its imaging, respectively. To overcome the insuficient spatial resolution of the conunting type imaging detectors like μ NID, nGEM and pixelated detectors, camera detectors combined with a neutron color image intensifier were investigated. At RANS center-of-gravity technique was applied to spots image obtained by a CCD camera and the technique was confirmed to be effective for improving spatial resolution. At RADEN a high-frame-rate CMOS camera was used and super resolution technique was applied and it was recognized that the spatial resolution was futhermore improved.

High-speed imaging using 3CCD camera and multi-color LED flashes

NASA Astrophysics Data System (ADS)

Hijazi, Ala; Friedl, Alexander; Cierpka, Christian; Kähler, Christian; Madhavan, Vis

2017-11-01

This paper demonstrates the possibility of capturing full-resolution, high-speed image sequences using a regular 3CCD color camera in conjunction with high-power light emitting diodes of three different colors. This is achieved using a novel approach, referred to as spectral-shuttering, where a high-speed image sequence is captured using short duration light pulses of different colors that are sent consecutively in very close succession. The work presented in this paper demonstrates the feasibility of configuring a high-speed camera system using low cost and readily available off-the-shelf components. This camera can be used for recording six-frame sequences at frame rates up to 20 kHz or three-frame sequences at even higher frame rates. Both color crosstalk and spatial matching between the different channels of the camera are found to be within acceptable limits. A small amount of magnification difference between the different channels is found and a simple calibration procedure for correcting the images is introduced. The images captured using the approach described here are of good quality to be used for obtaining full-field quantitative information using techniques such as digital image correlation and particle image velocimetry. A sequence of six high-speed images of a bubble splash recorded at 400 Hz is presented as a demonstration.

Joint estimation of high resolution images and depth maps from light field cameras

NASA Astrophysics Data System (ADS)

Ohashi, Kazuki; Takahashi, Keita; Fujii, Toshiaki

2014-03-01

Light field cameras are attracting much attention as tools for acquiring 3D information of a scene through a single camera. The main drawback of typical lenselet-based light field cameras is the limited resolution. This limitation comes from the structure where a microlens array is inserted between the sensor and the main lens. The microlens array projects 4D light field on a single 2D image sensor at the sacrifice of the resolution; the angular resolution and the position resolution trade-off under the fixed resolution of the image sensor. This fundamental trade-off remains after the raw light field image is converted to a set of sub-aperture images. The purpose of our study is to estimate a higher resolution image from low resolution sub-aperture images using a framework of super-resolution reconstruction. In this reconstruction, these sub-aperture images should be registered as accurately as possible. This registration is equivalent to depth estimation. Therefore, we propose a method where super-resolution and depth refinement are performed alternatively. Most of the process of our method is implemented by image processing operations. We present several experimental results using a Lytro camera, where we increased the resolution of a sub-aperture image by three times horizontally and vertically. Our method can produce clearer images compared to the original sub-aperture images and the case without depth refinement.

Automatic Generation of Passer-by Record Images using Internet Camera

NASA Astrophysics Data System (ADS)

Terada, Kenji; Atsuta, Koji

Recently, many brutal crimes have shocked us. On the other hand, we have seen a decline in the number of solved crimes. Therefore, the importance of security and self-defense has increased more and more. As an example of self-defense, many surveillance cameras are set up in the buildings, homes and offices. But even if we want to detect a suspicious person, we cannot check the surveillance videos immediately so that huge number of image sequences is stored in each video system. In this paper, we propose an automatic method of generating passer-by record images by using internet camera. In first step, the process of recognizing passer-by is carried out using an image sequence obtained from the internet camera. Our method classifies the subject region into each person by using the space-time image. In addition, we obtain the information of the time, direction and number of passey-by persons from this space-time image. Next, the present method detects five characteristics: the gravity of center, the position of person's head, the brightness, the size, and the shape of person. Finaly, an image of each person is selected among the image sequence by integrating five characteristics, and is added into the passer-by record image. Some experimental results using a simple experimental system are also reported, which indicate effectiveness of the proposed method. In most scenes, the every persons was able to be detected by the proposed method and the passer-by record image was generated.

Experimental comparison of high-density scintillators for EMCCD-based gamma ray imaging

NASA Astrophysics Data System (ADS)

Heemskerk, Jan W. T.; Kreuger, Rob; Goorden, Marlies C.; Korevaar, Marc A. N.; Salvador, Samuel; Seeley, Zachary M.; Cherepy, Nerine J.; van der Kolk, Erik; Payne, Stephen A.; Dorenbos, Pieter; Beekman, Freek J.

2012-07-01

Detection of x-rays and gamma rays with high spatial resolution can be achieved with scintillators that are optically coupled to electron-multiplying charge-coupled devices (EMCCDs). These can be operated at typical frame rates of 50 Hz with low noise. In such a set-up, scintillation light within each frame is integrated after which the frame is analyzed for the presence of scintillation events. This method allows for the use of scintillator materials with relatively long decay times of a few milliseconds, not previously considered for use in photon-counting gamma cameras, opening up an unexplored range of dense scintillators. In this paper, we test CdWO4 and transparent polycrystalline ceramics of Lu2O3:Eu and (Gd,Lu)2O3:Eu as alternatives to currently used CsI:Tl in order to improve the performance of EMCCD-based gamma cameras. The tested scintillators were selected for their significantly larger cross-sections at 140 keV (99mTc) compared to CsI:Tl combined with moderate to good light yield. A performance comparison based on gamma camera spatial and energy resolution was done with all tested scintillators having equal (66%) interaction probability at 140 keV. CdWO4, Lu2O3:Eu and (Gd,Lu)2O3:Eu all result in a significantly improved spatial resolution over CsI:Tl, albeit at the cost of reduced energy resolution. Lu2O3:Eu transparent ceramic gives the best spatial resolution: 65 µm full-width-at-half-maximum (FWHM) compared to 147 µm FWHM for CsI:Tl. In conclusion, these ‘slow’ dense scintillators open up new possibilities for improving the spatial resolution of EMCCD-based scintillation cameras.

Matching Images to Models: Camera Calibration for 3-D Surface Reconstruction

NASA Technical Reports Server (NTRS)

Morris, Robin D.; Smelyanskiy, Vadim N.; Cheeseman. Peter C.; Norvig, Peter (Technical Monitor)

2001-01-01

In a previous paper we described a system which recursively recovers a super-resolved three dimensional surface model from a set of images of the surface. In that paper we assumed that the camera calibration for each image was known. In this paper we solve two problems. Firstly, if an estimate of the surface is already known, the problem is to calibrate a new image relative to the existing surface model. Secondly, if no surface estimate is available, the relative camera calibration between the images in the set must be estimated. This will allow an initial surface model to be estimated. Results of both types of estimation are given.

[Evaluation of crossing calibration of (123)I-MIBG H/M ration, with the IDW scatter correction method, on different gamma camera systems].

PubMed

Kittaka, Daisuke; Takase, Tadashi; Akiyama, Masayuki; Nakazawa, Yasuo; Shinozuka, Akira; Shirai, Muneaki

2011-01-01

(123)I-MIBG Heart-to-Mediastinum activity ratio (H/M) is commonly used as an indicator of relative myocardial (123)I-MIBG uptake. H/M ratios reflect myocardial sympathetic nerve function, therefore it is a useful parameter to assess regional myocardial sympathetic denervation in various cardiac diseases. However, H/M ratio values differ by site, gamma camera system, position and size of region of interest (ROI), and collimator. In addition to these factors, 529 keV scatter component may also affect (123)I-MIBG H/M ratio. In this study, we examined whether the H/M ratio shows correlation between two different gamma camera systems and that sought for H/M ratio calculation formula. Moreover, we assessed the feasibility of (123)I Dual Window (IDW) method, which is a scatter correction method, and compared H/M ratios with and without IDW method. H/M ratio displayed a good correlation between two gamma camera systems. Additionally, we were able to create a new H/M calculation formula. These results indicated that the IDW method is a useful scatter correction method for calculating (123)I-MIBG H/M ratios.

Low-complexity camera digital signal imaging for video document projection system

NASA Astrophysics Data System (ADS)

Hsia, Shih-Chang; Tsai, Po-Shien

2011-04-01

We present high-performance and low-complexity algorithms for real-time camera imaging applications. The main functions of the proposed camera digital signal processing (DSP) involve color interpolation, white balance, adaptive binary processing, auto gain control, and edge and color enhancement for video projection systems. A series of simulations demonstrate that the proposed method can achieve good image quality while keeping computation cost and memory requirements low. On the basis of the proposed algorithms, the cost-effective hardware core is developed using Verilog HDL. The prototype chip has been verified with one low-cost programmable device. The real-time camera system can achieve 1270 × 792 resolution with the combination of extra components and can demonstrate each DSP function.

Image quality enhancement method for on-orbit remote sensing cameras using invariable modulation transfer function.

PubMed

Li, Jin; Liu, Zilong

2017-07-24

Remote sensing cameras in the visible/near infrared range are essential tools in Earth-observation, deep-space exploration, and celestial navigation. Their imaging performance, i.e. image quality here, directly determines the target-observation performance of a spacecraft, and even the successful completion of a space mission. Unfortunately, the camera itself, such as a optical system, a image sensor, and a electronic system, limits the on-orbit imaging performance. Here, we demonstrate an on-orbit high-resolution imaging method based on the invariable modulation transfer function (IMTF) of cameras. The IMTF, which is stable and invariable to the changing of ground targets, atmosphere, and environment on orbit or on the ground, depending on the camera itself, is extracted using a pixel optical focal-plane (PFP). The PFP produces multiple spatial frequency targets, which are used to calculate the IMTF at different frequencies. The resulting IMTF in combination with a constrained least-squares filter compensates for the IMTF, which represents the removal of the imaging effects limited by the camera itself. This method is experimentally confirmed. Experiments on an on-orbit panchromatic camera indicate that the proposed method increases 6.5 times of the average gradient, 3.3 times of the edge intensity, and 1.56 times of the MTF value compared to the case when IMTF is not used. This opens a door to push the limitation of a camera itself, enabling high-resolution on-orbit optical imaging.

Only Image Based for the 3d Metric Survey of Gothic Structures by Using Frame Cameras and Panoramic Cameras

NASA Astrophysics Data System (ADS)

Pérez Ramos, A.; Robleda Prieto, G.

2016-06-01

Indoor Gothic apse provides a complex environment for virtualization using imaging techniques due to its light conditions and architecture. Light entering throw large windows in combination with the apse shape makes difficult to find proper conditions to photo capture for reconstruction purposes. Thus, documentation techniques based on images are usually replaced by scanning techniques inside churches. Nevertheless, the need to use Terrestrial Laser Scanning (TLS) for indoor virtualization means a significant increase in the final surveying cost. So, in most cases, scanning techniques are used to generate dense point clouds. However, many Terrestrial Laser Scanner (TLS) internal cameras are not able to provide colour images or cannot reach the image quality that can be obtained using an external camera. Therefore, external quality images are often used to build high resolution textures of these models. This paper aims to solve the problem posted by virtualizing indoor Gothic churches, making that task more affordable using exclusively techniques base on images. It reviews a previous proposed methodology using a DSRL camera with 18-135 lens commonly used for close range photogrammetry and add another one using a HDR 360° camera with four lenses that makes the task easier and faster in comparison with the previous one. Fieldwork and office-work are simplified. The proposed methodology provides photographs in such a good conditions for building point clouds and textured meshes. Furthermore, the same imaging resources can be used to generate more deliverables without extra time consuming in the field, for instance, immersive virtual tours. In order to verify the usefulness of the method, it has been decided to apply it to the apse since it is considered one of the most complex elements of Gothic churches and it could be extended to the whole building.

Development of Simultaneous Beta-and-Coincidence-Gamma Imager for Plant Imaging Research

DOE Office of Scientific and Technical Information (OSTI.GOV)

Tai, Yuan-Chuan

2016-09-30

The goal of this project is to develop a novel imaging system that can simultaneously acquire beta and coincidence gamma images of positron sources in thin objects such as leaves of plants. This hybrid imager can be used to measure carbon assimilation in plants quantitatively and in real-time after C-11 labeled carbon-dioxide is administered. A better understanding of carbon assimilation, particularly under the increasingly elevated atmospheric CO 2 level, is extremely critical for plant scientists who study food crop and biofuel production. Phase 1 of this project is focused on the technology development with 3 specific aims: (1) develop amore » hybrid detector that can detect beta and gamma rays simultaneously; (2) develop an imaging system that can differentiate these two types of radiation and acquire beta and coincidence gamma images in real-time; (3) develop techniques to quantify radiotracer distribution using beta and gamma images. Phase 2 of this project is to apply technologies developed in phase 1 to study plants using positron-emitting radionuclide such as 11C to study carbon assimilation in biofuel plants.« less

Photometric Calibration and Image Stitching for a Large Field of View Multi-Camera System

PubMed Central

Lu, Yu; Wang, Keyi; Fan, Gongshu

2016-01-01

A new compact large field of view (FOV) multi-camera system is introduced. The camera is based on seven tiny complementary metal-oxide-semiconductor sensor modules covering over 160° × 160° FOV. Although image stitching has been studied extensively, sensor and lens differences have not been considered in previous multi-camera devices. In this study, we have calibrated the photometric characteristics of the multi-camera device. Lenses were not mounted on the sensor in the process of radiometric response calibration to eliminate the influence of the focusing effect of uniform light from an integrating sphere. Linearity range of the radiometric response, non-linearity response characteristics, sensitivity, and dark current of the camera response function are presented. The R, G, and B channels have different responses for the same illuminance. Vignetting artifact patterns have been tested. The actual luminance of the object is retrieved by sensor calibration results, and is used to blend images to make panoramas reflect the objective luminance more objectively. This compensates for the limitation of stitching images that are more realistic only through the smoothing method. The dynamic range limitation of can be resolved by using multiple cameras that cover a large field of view instead of a single image sensor with a wide-angle lens. The dynamic range is expanded by 48-fold in this system. We can obtain seven images in one shot with this multi-camera system, at 13 frames per second. PMID:27077857

Technology and Technique Standards for Camera-Acquired Digital Dermatologic Images: A Systematic Review.

PubMed

Quigley, Elizabeth A; Tokay, Barbara A; Jewell, Sarah T; Marchetti, Michael A; Halpern, Allan C

2015-08-01

Photographs are invaluable dermatologic diagnostic, management, research, teaching, and documentation tools. Digital Imaging and Communications in Medicine (DICOM) standards exist for many types of digital medical images, but there are no DICOM standards for camera-acquired dermatologic images to date. To identify and describe existing or proposed technology and technique standards for camera-acquired dermatologic images in the scientific literature. Systematic searches of the PubMed, EMBASE, and Cochrane databases were performed in January 2013 using photography and digital imaging, standardization, and medical specialty and medical illustration search terms and augmented by a gray literature search of 14 websites using Google. Two reviewers independently screened titles of 7371 unique publications, followed by 3 sequential full-text reviews, leading to the selection of 49 publications with the most recent (1985-2013) or detailed description of technology or technique standards related to the acquisition or use of images of skin disease (or related conditions). No universally accepted existing technology or technique standards for camera-based digital images in dermatology were identified. Recommendations are summarized for technology imaging standards, including spatial resolution, color resolution, reproduction (magnification) ratios, postacquisition image processing, color calibration, compression, output, archiving and storage, and security during storage and transmission. Recommendations are also summarized for technique imaging standards, including environmental conditions (lighting, background, and camera position), patient pose and standard view sets, and patient consent, privacy, and confidentiality. Proposed standards for specific-use cases in total body photography, teledermatology, and dermoscopy are described. The literature is replete with descriptions of obtaining photographs of skin disease, but universal imaging standards have not been developed

NPS assessment of color medical image displays using a monochromatic CCD camera

NASA Astrophysics Data System (ADS)

Roehrig, Hans; Gu, Xiliang; Fan, Jiahua

2012-10-01

This paper presents an approach to Noise Power Spectrum (NPS) assessment of color medical displays without using an expensive imaging colorimeter. The R, G and B color uniform patterns were shown on the display under study and the images were taken using a high resolution monochromatic camera. A colorimeter was used to calibrate the camera images. Synthetic intensity images were formed by the weighted sum of the R, G, B and the dark screen images. Finally the NPS analysis was conducted on the synthetic images. The proposed method replaces an expensive imaging colorimeter for NPS evaluation, which also suggests a potential solution for routine color medical display QA/QC in the clinical area, especially when imaging of display devices is desired

The Advanced Gamma-ray Imaging System (AGIS): Topological Array Trigger

NASA Astrophysics Data System (ADS)

Smith, Andrew W.

2010-03-01

AGIS is a concept for the next-generation ground-based gamma-ray observatory. It will be an array of 36 imaging atmospheric Cherenkov telescopes (IACTs) sensitive in the energy range from 50 GeV to 200 TeV. The required improvements in sensitivity, angular resolution, and reliability of operation relative to the present generation instruments imposes demanding technological and cost requirements on the design of the telescopes and on the triggering and readout systems for AGIS. To maximize the capabilities of large arrays of IACTs with a low energy threshold, a wide field of view and a low background rate, a sophisticated array trigger is required. We outline the status of the development of a stereoscopic array trigger that calculates image parameters and correlates them across a subset of telescopes. Field Programmable Gate Arrays (FPGAs) implement the real-time pattern recognition to suppress cosmic rays and night-sky background events. A proof of principle system is being developed to run at camera trigger rates up to 10MHz and array-level rates up to 10kHz.

Color camera computed tomography imaging spectrometer for improved spatial-spectral image accuracy

NASA Technical Reports Server (NTRS)

Wilson, Daniel W. (Inventor); Bearman, Gregory H. (Inventor); Johnson, William R. (Inventor)

2011-01-01

Computed tomography imaging spectrometers ("CTIS"s) having color focal plane array detectors are provided. The color FPA detector may comprise a digital color camera including a digital image sensor, such as a Foveon X3.RTM. digital image sensor or a Bayer color filter mosaic. In another embodiment, the CTIS includes a pattern imposed either directly on the object scene being imaged or at the field stop aperture. The use of a color FPA detector and the pattern improves the accuracy of the captured spatial and spectral information.

SU-F-J-189: A Method to Improve the Spatial Resolution of Prompt Gamma Based Compton Imaging for Proton Range Verification

DOE Office of Scientific and Technical Information (OSTI.GOV)

Draeger, E; Chen, H; Polf, J

Purpose: To test two new techniques, the distance-of-closest approach (DCA) and Compton line (CL) filters, developed as a means of improving the spatial resolution of Compton camera (CC) imaging. Methods: Gammas emitted from {sup 22}Na, {sup 137}Cs, and {sup 60}Co point sources were measured with a prototype 3-stage CC. The energy deposited and position of each interaction in each stage were recorded and used to calculate a “cone-of-origin” for each gamma that scattered twice in the CC. A DCA filter was developed which finds the shortest distance from the gamma’s cone-of-origin surface to the location of the gamma source. Themore » DCA filter was applied to the data to determine the initial energy of the gamma and to remove “bad” interactions that only contribute noise to the image. Additionally, a CL filter, which removes gamma events that do not follow the theoretical predictions of the Compton scatter equation, was used to further remove “bad” interactions from the measured data. Then images were reconstructed with raw, unfiltered data, DCA filtered data, and DCA+CL filtered data and the achievable image resolution of each dataset was compared. Results: Spatial resolutions of ∼2 mm, and better than 2 mm, were achievable with the DCA and DCA+CL filtered data, respectively, compared to > 5 mm for the raw, unfiltered data. Conclusion: In many special cases in medical imaging where information about the source position may be known, such as proton radiotherapy range verification, the application of the DCA and CL filters can result in considerable improvements in the achievable spatial resolutions of Compton imaging.« less

Enhancing swimming pool safety by the use of range-imaging cameras

NASA Astrophysics Data System (ADS)

Geerardyn, D.; Boulanger, S.; Kuijk, M.

2015-05-01

Drowning is the cause of death of 372.000 people, each year worldwide, according to the report of November 2014 of the World Health Organization.1 Currently, most swimming pools only use lifeguards to detect drowning people. In some modern swimming pools, camera-based detection systems are nowadays being integrated. However, these systems have to be mounted underwater, mostly as a replacement of the underwater lighting. In contrast, we are interested in range imaging cameras mounted on the ceiling of the swimming pool, allowing to distinguish swimmers at the surface from drowning people underwater, while keeping the large field-of-view and minimizing occlusions. However, we have to take into account that the water surface of a swimming pool is not a flat, but mostly rippled surface, and that the water is transparent for visible light, but less transparent for infrared or ultraviolet light. We investigated the use of different types of 3D cameras to detect objects underwater at different depths and with different amplitudes of surface perturbations. Specifically, we performed measurements with a commercial Time-of-Flight camera, a commercial structured-light depth camera and our own Time-of-Flight system. Our own system uses pulsed Time-of-Flight and emits light of 785 nm. The measured distances between the camera and the object are influenced through the perturbations on the water surface. Due to the timing of our Time-of-Flight camera, our system is theoretically able to minimize the influence of the reflections of a partially-reflecting surface. The combination of a post image-acquisition filter compensating for the perturbations and the use of a light source with shorter wavelengths to enlarge the depth range can improve the current commercial cameras. As a result, we can conclude that low-cost range imagers can increase swimming pool safety, by inserting a post-processing filter and the use of another light source.

Estimation and correction of produced light from prompt gamma photons on luminescence imaging of water for proton therapy dosimetry

NASA Astrophysics Data System (ADS)

Yabe, Takuya; Komori, Masataka; Toshito, Toshiyuki; Yamaguchi, Mitsutaka; Kawachi, Naoki; Yamamoto, Seiichi

2018-02-01

Although the luminescence images of water during proton-beam irradiation using a cooled charge-coupled device camera showed almost the same ranges of proton beams as those measured by an ionization chamber, the depth profiles showed lower Bragg peak intensities than those measured by an ionization chamber. In addition, a broad optical baseline signal was observed in depths that exceed the depth of the Bragg peak. We hypothesize that this broad baseline signal originates from the interaction of proton-induced prompt gamma photons with water. These prompt gamma photons interact with water to form high-energy Compton electrons, which may cause luminescence or Cherenkov emission from depths exceeding the location of the Bragg peak. To clarify this idea, we measured the luminescence images of water during the irradiations of protons in water with minimized parallax errors, and also simulated the produced light by the interactions of prompt gamma photons with water. We corrected the measured depth profiles of the luminescence images by subtracting the simulated distributions of the produced light by the interactions of prompt gamma photons in water. Corrections were also conducted using the estimated depth profiles of the light of the prompt gamma photons, as obtained from the off-beam areas of the luminescence images of water. With these corrections, we successfully obtained depth profiles that have almost identical distributions as the simulated dose distributions for protons. The percentage relative height of the Bragg peak with corrections to that of the simulation data increased to 94% from 80% without correction. Also, the percentage relative offset heights of the deeper part of the Bragg peak with corrections decreased to 0.2%-0.4% from 4% without correction. These results indicate that the luminescence imaging of water has potential for the dose distribution measurements for proton therapy dosimetry.

Exploring the imaging properties of thin lenses for cryogenic infrared cameras

NASA Astrophysics Data System (ADS)

Druart, Guillaume; Verdet, Sebastien; Guerineau, Nicolas; Magli, Serge; Chambon, Mathieu; Grulois, Tatiana; Matallah, Noura

2016-05-01

Designing a cryogenic camera is a good strategy to miniaturize and simplify an infrared camera using a cooled detector. Indeed, the integration of optics inside the cold shield allows to simply athermalize the design, guarantees a cold pupil and releases the constraint on having a high back focal length for small focal length systems. By this way, cameras made of a single lens or two lenses are viable systems with good optical features and a good stability in image correction. However it involves a relatively significant additional optical mass inside the dewar and thus increases the cool down time of the camera. ONERA is currently exploring a minimalist strategy consisting in giving an imaging function to thin optical plates that are found in conventional dewars. By this way, we could make a cryogenic camera that has the same cool down time as a traditional dewar without an imagery function. Two examples will be presented: the first one is a camera using a dual-band infrared detector made of a lens outside the dewar and a lens inside the cold shield, the later having the main optical power of the system. We were able to design a cold plano-convex lens with a thickness lower than 1mm. The second example is an evolution of a former cryogenic camera called SOIE. We replaced the cold meniscus by a plano-convex Fresnel lens with a decrease of the optical thermal mass of 66%. The performances of both cameras will be compared.

Evolutionary Fuzzy Block-Matching-Based Camera Raw Image Denoising.

PubMed

Yang, Chin-Chang; Guo, Shu-Mei; Tsai, Jason Sheng-Hong

2017-09-01

An evolutionary fuzzy block-matching-based image denoising algorithm is proposed to remove noise from a camera raw image. Recently, a variance stabilization transform is widely used to stabilize the noise variance, so that a Gaussian denoising algorithm can be used to remove the signal-dependent noise in camera sensors. However, in the stabilized domain, the existed denoising algorithm may blur too much detail. To provide a better estimate of the noise-free signal, a new block-matching approach is proposed to find similar blocks by the use of a type-2 fuzzy logic system (FLS). Then, these similar blocks are averaged with the weightings which are determined by the FLS. Finally, an efficient differential evolution is used to further improve the performance of the proposed denoising algorithm. The experimental results show that the proposed denoising algorithm effectively improves the performance of image denoising. Furthermore, the average performance of the proposed method is better than those of two state-of-the-art image denoising algorithms in subjective and objective measures.

Development and Evaluation of Real-Time Volumetric Compton Gamma-Ray Imaging

NASA Astrophysics Data System (ADS)

Barnowski, Ross Wegner

An approach to gamma-ray imaging has been developed that enables near real-time volumetric (3D) imaging of unknown environments thus improving the utility of gamma-ray imaging for source-search and radiation mapping applications. The approach, herein dubbed scene data fusion (SDF), is based on integrating mobile radiation imagers with real time tracking and scene reconstruction algorithms to enable a mobile mode of operation and 3D localization of gamma-ray sources. The real-time tracking allows the imager to be moved throughout the environment or around a particular object of interest, obtaining the multiple perspectives necessary for standoff 3D imaging. A 3D model of the scene, provided in real-time by a simultaneous localization and mapping (SLAM) algorithm, can be incorporated into the image reconstruction reducing the reconstruction time and improving imaging performance. The SDF concept is demonstrated in this work with a Microsoft Kinect RGB-D sensor, a real-time SLAM solver, and two different mobile gamma-ray imaging platforms. The first is a cart-based imaging platform known as the Volumetric Compton Imager (VCI), comprising two 3D position-sensitive high purity germanium (HPGe) detectors, exhibiting excellent gamma-ray imaging characteristics, but with limited mobility due to the size and weight of the cart. The second system is the High Efficiency Multimodal Imager (HEMI) a hand-portable gamma-ray imager comprising 96 individual cm3 CdZnTe crystals arranged in a two-plane, active-mask configuration. The HEMI instrument has poorer energy and angular resolution than the VCI, but is truly hand-portable, allowing the SDF concept to be tested in multiple environments and for more challenging imaging scenarios. An iterative algorithm based on Compton kinematics is used to reconstruct the gamma-ray source distribution in all three spatial dimensions. Each of the two mobile imaging systems are used to demonstrate SDF for a variety of scenarios, including

Quantifying biodiversity using digital cameras and automated image analysis.

NASA Astrophysics Data System (ADS)

Roadknight, C. M.; Rose, R. J.; Barber, M. L.; Price, M. C.; Marshall, I. W.

2009-04-01

Monitoring the effects on biodiversity of extensive grazing in complex semi-natural habitats is labour intensive. There are also concerns about the standardization of semi-quantitative data collection. We have chosen to focus initially on automating the most time consuming aspect - the image analysis. The advent of cheaper and more sophisticated digital camera technology has lead to a sudden increase in the number of habitat monitoring images and information that is being collected. We report on the use of automated trail cameras (designed for the game hunting market) to continuously capture images of grazer activity in a variety of habitats at Moor House National Nature Reserve, which is situated in the North of England at an average altitude of over 600m. Rainfall is high, and in most areas the soil consists of deep peat (1m to 3m), populated by a mix of heather, mosses and sedges. The cameras have been continuously in operation over a 6 month period, daylight images are in full colour and night images (IR flash) are black and white. We have developed artificial intelligence based methods to assist in the analysis of the large number of images collected, generating alert states for new or unusual image conditions. This paper describes the data collection techniques, outlines the quantitative and qualitative data collected and proposes online and offline systems that can reduce the manpower overheads and increase focus on important subsets in the collected data. By converting digital image data into statistical composite data it can be handled in a similar way to other biodiversity statistics thus improving the scalability of monitoring experiments. Unsupervised feature detection methods and supervised neural methods were tested and offered solutions to simplifying the process. Accurate (85 to 95%) categorization of faunal content can be obtained, requiring human intervention for only those images containing rare animals or unusual (undecidable) conditions, and

First demonstration of aerial gamma-ray imaging using drone for prompt radiation survey in Fukushima

NASA Astrophysics Data System (ADS)

Mochizuki, S.; Kataoka, J.; Tagawa, L.; Iwamoto, Y.; Okochi, H.; Katsumi, N.; Kinno, S.; Arimoto, M.; Maruhashi, T.; Fujieda, K.; Kurihara, T.; Ohsuka, S.

2017-11-01

Considerable amounts of radioactive substances (mainly 137Cs and 134Cs) were released into the environment after the Japanese nuclear disaster in 2011. Some restrictions on residence areas were lifted in April 2017, owing to the successive and effective decontamination operations. However, the distribution of radioactive substances in vast areas of mountain, forest and satoyama close to the city is still unknown; thus, decontamination operations in such areas are being hampered. In this paper, we report on the first aerial gamma-ray imaging of a schoolyard in Fukushima using a drone that carries a high sensitivity Compton camera. We show that the distribution of 137Cs in regions with a diameter of several tens to a hundred meters can be imaged with a typical resolution of 2-5 m within a 10-20 min flights duration. The aerial gamma-ray images taken 10 m and 20 m above the ground are qualitatively consistent with a dose map reconstructed from the ground-based measurements using a survey meter. Although further quantification is needed for the distance and air-absorption corrections to derive in situ dose map, such an aerial drone system can reduce measurement time by a factor of ten and is suitable for place where ground-based measurement are difficult.

A novel design for scintillator-based neutron and gamma imaging in inertial confinement fusion

NASA Astrophysics Data System (ADS)

Geppert-Kleinrath, Verena; Cutler, Theresa; Danly, Chris; Madden, Amanda; Merrill, Frank; Tybo, Josh; Volegov, Petr; Wilde, Carl

2017-10-01

The LANL Advanced Imaging team has been providing reliable 2D neutron imaging of the burning fusion fuel at NIF for years, revealing possible multi-dimensional asymmetries in the fuel shape, and therefore calling for additional views. Adding a passive imaging system using image plate techniques along a new polar line of sight has recently demonstrated the merit of 3D neutron image reconstruction. Now, the team is in the process of designing a new active neutron imaging system for an additional equatorial view. The design will include a gamma imaging system as well, to allow for the imaging of carbon in the ablator of the NIF fuel capsules, constraining the burning fuel shape even further. The selection of ideal scintillator materials for a position-sensitive detector system is the key component for the new design. A comprehensive study of advanced scintillators has been carried out at the Los Alamos Neutron Science Center and the OMEGA Laser Facility in Rochester, NY. Neutron radiography using a fast-gated CCD camera system delivers measurements of resolution, light output and noise characteristics. The measured performance parameters inform the novel design, for which we conclude the feasibility of monolithic scintillators over pixelated counterparts.

Introduction of A New Toolbox for Processing Digital Images From Multiple Camera Networks: FMIPROT

NASA Astrophysics Data System (ADS)

Melih Tanis, Cemal; Nadir Arslan, Ali

2017-04-01

Webcam networks intended for scientific monitoring of ecosystems is providing digital images and other environmental data for various studies. Also, other types of camera networks can also be used for scientific purposes, e.g. usage of traffic webcams for phenological studies, camera networks for ski tracks and avalanche monitoring over mountains for hydrological studies. To efficiently harness the potential of these camera networks, easy to use software which can obtain and handle images from different networks having different protocols and standards is necessary. For the analyses of the images from webcam networks, numerous software packages are freely available. These software packages have different strong features not only for analyzing but also post processing digital images. But specifically for the ease of use, applicability and scalability, a different set of features could be added. Thus, a more customized approach would be of high value, not only for analyzing images of comprehensive camera networks, but also considering the possibility to create operational data extraction and processing with an easy to use toolbox. At this paper, we introduce a new toolbox, entitled; Finnish Meteorological Institute Image PROcessing Tool (FMIPROT) which a customized approach is followed. FMIPROT has currently following features: • straightforward installation, • no software dependencies that require as extra installations, • communication with multiple camera networks, • automatic downloading and handling images, • user friendly and simple user interface, • data filtering, • visualizing results on customizable plots, • plugins; allows users to add their own algorithms. Current image analyses in FMIPROT include "Color Fraction Extraction" and "Vegetation Indices". The analysis of color fraction extraction is calculating the fractions of the colors in a region of interest, for red, green and blue colors along with brightness and luminance parameters. The

Low Frequency Flats for Imaging Cameras on the Hubble Space Telescope

NASA Astrophysics Data System (ADS)

Kossakowski, Diana; Avila, Roberto J.; Borncamp, David; Grogin, Norman A.

2017-01-01

We created a revamped Low Frequency Flat (L-Flat) algorithm for the Hubble Space Telescope (HST) and all of its imaging cameras. The current program that makes these calibration files does not compile on modern computer systems and it requires translation to Python. We took the opportunity to explore various methods that reduce the scatter of photometric observations using chi-squared optimizers along with Markov Chain Monte Carlo (MCMC). We created simulations to validate the algorithms and then worked with the UV photometry of the globular cluster NGC6681 to update the calibration files for the Advanced Camera for Surveys (ACS) and Solar Blind Channel (SBC). The new software was made for general usage and therefore can be applied to any of the current imaging cameras on HST.

Relative Panoramic Camera Position Estimation for Image-Based Virtual Reality Networks in Indoor Environments

NASA Astrophysics Data System (ADS)

Nakagawa, M.; Akano, K.; Kobayashi, T.; Sekiguchi, Y.

2017-09-01

Image-based virtual reality (VR) is a virtual space generated with panoramic images projected onto a primitive model. In imagebased VR, realistic VR scenes can be generated with lower rendering cost, and network data can be described as relationships among VR scenes. The camera network data are generated manually or by an automated procedure using camera position and rotation data. When panoramic images are acquired in indoor environments, network data should be generated without Global Navigation Satellite Systems (GNSS) positioning data. Thus, we focused on image-based VR generation using a panoramic camera in indoor environments. We propose a methodology to automate network data generation using panoramic images for an image-based VR space. We verified and evaluated our methodology through five experiments in indoor environments, including a corridor, elevator hall, room, and stairs. We confirmed that our methodology can automatically reconstruct network data using panoramic images for image-based VR in indoor environments without GNSS position data.

Dual cameras acquisition and display system of retina-like sensor camera and rectangular sensor camera

NASA Astrophysics Data System (ADS)

Cao, Nan; Cao, Fengmei; Lin, Yabin; Bai, Tingzhu; Song, Shengyu

2015-04-01

For a new kind of retina-like senor camera and a traditional rectangular sensor camera, dual cameras acquisition and display system need to be built. We introduce the principle and the development of retina-like senor. Image coordinates transformation and interpolation based on sub-pixel interpolation need to be realized for our retina-like sensor's special pixels distribution. The hardware platform is composed of retina-like senor camera, rectangular sensor camera, image grabber and PC. Combined the MIL and OpenCV library, the software program is composed in VC++ on VS 2010. Experience results show that the system can realizes two cameras' acquisition and display.

Removing cosmic-ray hits from multiorbit HST Wide Field Camera images

NASA Technical Reports Server (NTRS)

Windhorst, Rogier A.; Franklin, Barbara E.; Neuschaefer, Lyman W.

1994-01-01

We present an optimized algorithm that removes cosmic rays ('CRs') from multiorbit Hubble Space Telescope (HST) Wide Field/Planetary Camera ('WF/PC') images. It computes the image noise in every iteration from the WF/PC CCD equation. This includes all known sources of random and systematic calibration errors. We test this algorithm on WF/PC stacks of 2-12 orbits as a function of the number of available orbits and the formal Poissonian sigma-clipping level. We find that the algorithm needs greater than or equal 4 WF/PC exposures to locate the minimal sky signal (which is noticeably affected by CRs), with an optimal clipping level at 2-2.5 x sigma(sub Poisson). We analyze the CR flux detected on multiorbit 'CR stacks,' which are constructed by subtracting the best CR filtered images from the unfiltered 8-12 orbit average. We use an automated object finder to determine the surface density of CRS as a function of the apparent magnitude (or ADU flux) they would have generated in the images had they not been removed. The power law slope of the CR 'counts' (gamma approximately = 0.6 for N(m) m(exp gamma)) is steeper than that of the faint galaxy counts down to V approximately = 28 mag. The CR counts show a drop off between 28 less than or approximately V less than or approximately 30 mag (the latter is our formal 2 sigma point source sensitivity without spherical aberration). This prevents the CR sky integral from diverging, and is likely due to a real cutoff in the CR energy distribution below approximately 11 ADU per orbit. The integral CR surface density is less than or approximately 10(exp 8)/sq. deg, and their sky signal is V approximately = 25.5-27.0 mag/sq. arcsec, or 3%-13% of our NEP sky background (V = 23.3 mag/sq. arcsec), and well above the EBL integral of the deepest galaxy counts (B(sub J) approximately = 28.0 mag/sq. arcsec). We conclude that faint CRs will always contribute to the sky signal in the deepest WF/PC images. Since WFPC2 has approximately 2.7x

High resolution phoswich gamma-ray imager utilizing monolithic MPPC arrays with submillimeter pixelized crystals

NASA Astrophysics Data System (ADS)

Kato, T.; Kataoka, J.; Nakamori, T.; Kishimoto, A.; Yamamoto, S.; Sato, K.; Ishikawa, Y.; Yamamura, K.; Kawabata, N.; Ikeda, H.; Kamada, K.

2013-05-01

We report the development of a high spatial resolution tweezers-type coincidence gamma-ray camera for medical imaging. This application consists of large-area monolithic Multi-Pixel Photon Counters (MPPCs) and submillimeter pixelized scintillator matrices. The MPPC array has 4 × 4 channels with a three-side buttable, very compact package. For typical operational gain of 7.5 × 105 at + 20 °C, gain fluctuation over the entire MPPC device is only ± 5.6%, and dark count rates (as measured at the 1 p.e. level) amount to <= 400 kcps per channel. We selected Ce-doped (Lu,Y)2(SiO4)O (Ce:LYSO) and a brand-new scintillator, Ce-doped Gd3Al2Ga3O12 (Ce:GAGG) due to their high light yield and density. To improve the spatial resolution, these scintillators were fabricated into 15 × 15 matrices of 0.5 × 0.5 mm2 pixels. The Ce:LYSO and Ce:GAGG scintillator matrices were assembled into phosphor sandwich (phoswich) detectors, and then coupled to the MPPC array along with an acrylic light guide measuring 1 mm thick, and with summing operational amplifiers that compile the signals into four position-encoded analog outputs being used for signal readout. Spatial resolution of 1.1 mm was achieved with the coincidence imaging system using a 22Na point source. These results suggest that the gamma-ray imagers offer excellent potential for applications in high spatial medical imaging.

Experimental Comparison of Knife-Edge and Multi-Parallel Slit Collimators for Prompt Gamma Imaging of Proton Pencil Beams.

PubMed

Smeets, Julien; Roellinghoff, Frauke; Janssens, Guillaume; Perali, Irene; Celani, Andrea; Fiorini, Carlo; Freud, Nicolas; Testa, Etienne; Prieels, Damien

2016-01-01

More and more camera concepts are being investigated to try and seize the opportunity of instantaneous range verification of proton therapy treatments offered by prompt gammas emitted along the proton tracks. Focusing on one-dimensional imaging with a passive collimator, the present study experimentally compared in combination with the first, clinically compatible, dedicated camera device the performances of instances of the two main options: a knife-edge slit (KES) and a multi-parallel slit (MPS) design. These two options were experimentally assessed in this specific context as they were previously demonstrated through analytical and numerical studies to allow similar performances in terms of Bragg peak retrieval precision and spatial resolution in a general context. Both collimators were prototyped according to the conclusions of Monte Carlo optimization studies under constraints of equal weight (40 mm tungsten alloy equivalent thickness) and of the specificities of the camera device under consideration (in particular 4 mm segmentation along beam axis and no time-of-flight discrimination, both of which less favorable to the MPS performance than to the KES one). Acquisitions of proton pencil beams of 100, 160, and 230 MeV in a PMMA target revealed that, in order to reach a given level of statistical precision on Bragg peak depth retrieval, the KES collimator requires only half the dose the present MPS collimator needs, making the KES collimator a preferred option for a compact camera device aimed at imaging only the Bragg peak position. On the other hand, the present MPS collimator proves more effective at retrieving the entrance of the beam in the target in the context of an extended camera device aimed at imaging the whole proton track within the patient.

A novel phoswich imaging detector for simultaneous beta and coincidence-gamma imaging of plant leaves.

PubMed

Wu, Heyu; Tai, Yuan-Chuan

2011-09-07

To meet the growing demand for functional imaging technology for use in studying plant biology, we are developing a novel technique that permits simultaneous imaging of escaped positrons and coincidence gammas from annihilation of positrons within an intake leaf. The multi-modality imaging system will include two planar detectors: one is a typical PET detector array and the other is a phoswich imaging detector that detects both beta and gamma. The novel phoswich detector is made of a plastic scintillator, a lutetium oxyorthosilicate (LSO) array, and a position sensitive photomultiplier tube (PS-PMT). The plastic scintillator serves as a beta detector, while the LSO array serves as a gamma detector and light guide that couples scintillation light from the plastic detector to the PMT. In our prototype, the PMT signal was fed into the Siemens QuickSilver electronics to achieve shaping and waveform sampling. Pulse-shape discrimination based on the detectors' decay times (2.1 ns for plastic and 40 ns for LSO) was used to differentiate beta and gamma events using the common PMT signals. Using our prototype phoswich detector, we simultaneously measured a beta image and gamma events (in single mode). The beta image showed a resolution of 1.6 mm full-width-at-half-maximum using F-18 line sources. Because this shows promise for plant-scale imaging, our future plans include development of a fully functional simultaneous beta-and-coincidence-gamma imager with sub-millimeter resolution imaging capability for both modalities.

Digital micromirror device camera with per-pixel coded exposure for high dynamic range imaging.

PubMed

Feng, Wei; Zhang, Fumin; Wang, Weijing; Xing, Wei; Qu, Xinghua

2017-05-01

In this paper, we overcome the limited dynamic range of the conventional digital camera, and propose a method of realizing high dynamic range imaging (HDRI) from a novel programmable imaging system called a digital micromirror device (DMD) camera. The unique feature of the proposed new method is that the spatial and temporal information of incident light in our DMD camera can be flexibly modulated, and it enables the camera pixels always to have reasonable exposure intensity by DMD pixel-level modulation. More importantly, it allows different light intensity control algorithms used in our programmable imaging system to achieve HDRI. We implement the optical system prototype, analyze the theory of per-pixel coded exposure for HDRI, and put forward an adaptive light intensity control algorithm to effectively modulate the different light intensity to recover high dynamic range images. Via experiments, we demonstrate the effectiveness of our method and implement the HDRI on different objects.

Achieving thermography with a thermal security camera using uncooled amorphous silicon microbolometer image sensors

NASA Astrophysics Data System (ADS)

Wang, Yu-Wei; Tesdahl, Curtis; Owens, Jim; Dorn, David

2012-06-01

Advancements in uncooled microbolometer technology over the last several years have opened up many commercial applications which had been previously cost prohibitive. Thermal technology is no longer limited to the military and government market segments. One type of thermal sensor with low NETD which is available in the commercial market segment is the uncooled amorphous silicon (α-Si) microbolometer image sensor. Typical thermal security cameras focus on providing the best image quality by auto tonemaping (contrast enhancing) the image, which provides the best contrast depending on the temperature range of the scene. While this may provide enough information to detect objects and activities, there are further benefits of being able to estimate the actual object temperatures in a scene. This thermographic ability can provide functionality beyond typical security cameras by being able to monitor processes. Example applications of thermography[2] with thermal camera include: monitoring electrical circuits, industrial machinery, building thermal leaks, oil/gas pipelines, power substations, etc...[3][5] This paper discusses the methodology of estimating object temperatures by characterizing/calibrating different components inside a thermal camera utilizing an uncooled amorphous silicon microbolometer image sensor. Plots of system performance across camera operating temperatures will be shown.

15 CFR 743.3 - Thermal imaging camera reporting.

Code of Federal Regulations, 2010 CFR

2010-01-01

... 15 Commerce and Foreign Trade 2 2010-01-01 2010-01-01 false Thermal imaging camera reporting. 743.3 Section 743.3 Commerce and Foreign Trade Regulations Relating to Commerce and Foreign Trade (Continued) BUREAU OF INDUSTRY AND SECURITY, DEPARTMENT OF COMMERCE EXPORT ADMINISTRATION REGULATIONS SPECIAL...

Semi-automated camera trap image processing for the detection of ungulate fence crossing events.

PubMed

Janzen, Michael; Visser, Kaitlyn; Visscher, Darcy; MacLeod, Ian; Vujnovic, Dragomir; Vujnovic, Ksenija

2017-09-27

Remote cameras are an increasingly important tool for ecological research. While remote camera traps collect field data with minimal human attention, the images they collect require post-processing and characterization before it can be ecologically and statistically analyzed, requiring the input of substantial time and money from researchers. The need for post-processing is due, in part, to a high incidence of non-target images. We developed a stand-alone semi-automated computer program to aid in image processing, categorization, and data reduction by employing background subtraction and histogram rules. Unlike previous work that uses video as input, our program uses still camera trap images. The program was developed for an ungulate fence crossing project and tested against an image dataset which had been previously processed by a human operator. Our program placed images into categories representing the confidence of a particular sequence of images containing a fence crossing event. This resulted in a reduction of 54.8% of images that required further human operator characterization while retaining 72.6% of the known fence crossing events. This program can provide researchers using remote camera data the ability to reduce the time and cost required for image post-processing and characterization. Further, we discuss how this procedure might be generalized to situations not specifically related to animal use of linear features.

‘Gamma Anna’: a classroom demonstration for teaching the concepts of gamma imaging

NASA Astrophysics Data System (ADS)

Wolff, Nicola; Griffiths, Jennifer; Yerworth, Rebecca

2017-01-01

Gamma imaging is at the interface of medicine and physics and thus its teaching is important in both fields. Pedagogic literature highlights the benefits of interactive demonstrations in teaching: an increase in enjoyment and interest, as well as improvement in academic achievement. However gamma imaging uses radioactive sources, which are potentially dangerous and thus their use is tightly controlled. We have developed a demonstration which uses a localised exothermic reaction within a rag doll as an analogue of radioactivity. This can be safely used in classrooms to demonstrate the principles of gamma imaging. The tool is easy to make, cheap, robust and portable. The supplementary material in this paper gives teacher notes and a description of how to make the rag doll demonstrator. We have tested the tool using six participants, acting as ‘teachers’, who carried out the demonstration and described the doll as easy to use, and the ‘tumour’ clearly identifiable. The teaching tool was separately demonstrated to a group of 12 GCSE physics students and a group of 12 medical students. Feedback showed increased student engagement, enjoyment and understanding of gamma imaging. Previous research has shown that these benefits have an impact on learning and academic outcomes.

A comparison between the use of a shadow shield whole body counter and an uncollimated gamma camera ain the assessment of the seven-day retention of SeHCAT.

PubMed

Hames, T K; Condon, B R; Fleming, J S; Phillips, G; Holdstock, G; Smith, C L; Howlett, P J; Ackery, D

1984-07-01

We have compared the 7-day retention of the radioisotope bile salt analogue SeHCAT (75Se-23-selena-25-homotaurocholate), by whole body counting and by uncollimated gamma camera measurement, in phantoms and in 25 patients with inflammatory bowel disease. The results correlate with a linear correlation coefficient of 0.96. An uncollimated gamma camera can be used to assess bile acid malabsorption when a whole body radioactivity monitor is not available.

Nuclear medicine imaging system

DOEpatents

Bennett, G.W.; Brill, A.B.; Bizais, Y.J.C.; Rowe, R.W.; Zubal, I.G.

1983-03-11

It is an object of this invention to provide a nuclear imaging system having the versatility to do positron annihilation studies, rotating single or opposed camera gamma emission studies, and orthogonal gamma emission studies. It is a further object of this invention to provide an imaging system having the capability for orthogonal dual multipinhole tomography. It is another object of this invention to provide a nuclear imaging system in which all available energy data, as well as patient physiological data, are acquired simultaneously in list mode.

The Mast Cameras and Mars Descent Imager (MARDI) for the 2009 Mars Science Laboratory

NASA Technical Reports Server (NTRS)

Malin, M. C.; Bell, J. F.; Cameron, J.; Dietrich, W. E.; Edgett, K. S.; Hallet, B.; Herkenhoff, K. E.; Lemmon, M. T.; Parker, T. J.; Sullivan, R. J.

2005-01-01

Based on operational experience gained during the Mars Exploration Rover (MER) mission, we proposed and were selected to conduct two related imaging experiments: (1) an investigation of the geology and short-term atmospheric vertical wind profile local to the Mars Science Laboratory (MSL) landing site using descent imaging, and (2) a broadly-based scientific investigation of the MSL locale employing visible and very near infra-red imaging techniques from a pair of mast-mounted, high resolution cameras. Both instruments share a common electronics design, a design also employed for the MSL Mars Hand Lens Imager (MAHLI) [1]. The primary differences between the cameras are in the nature and number of mechanisms and specific optics tailored to each camera s requirements.

Reducing flicker due to ambient illumination in camera captured images

NASA Astrophysics Data System (ADS)

Kim, Minwoong; Bengtson, Kurt; Li, Lisa; Allebach, Jan P.

2013-02-01

The flicker artifact dealt with in this paper is the scanning distortion arising when an image is captured by a digital camera using a CMOS imaging sensor with an electronic rolling shutter under strong ambient light sources powered by AC. This type of camera scans a target line-by-line in a frame. Therefore, time differences exist between the lines. This mechanism causes a captured image to be corrupted by the change of illumination. This phenomenon is called the flicker artifact. The non-content area of the captured image is used to estimate a flicker signal that is a key to being able to compensate the flicker artifact. The average signal of the non-content area taken along the scan direction has local extrema where the peaks of flicker exist. The locations of the extrema are very useful information to estimate the desired distribution of pixel intensities assuming that the flicker artifact does not exist. The flicker-reduced images compensated by our approach clearly demonstrate the reduced flicker artifact, based on visual observation.

[Evaluation of the efficacy of sentinel node detection in breast cancer: chronological course and influence of the incorporation of an intra-operative portable gamma camera].

PubMed

Goñi Gironés, E; Vicente García, F; Serra Arbeloa, P; Estébanez Estébanez, C; Calvo Benito, A; Rodrigo Rincón, I; Camarero Salazar, A; Martínez Lozano, M E

2013-01-01

To define the sentinel node identification rate in breast cancer, the chronological evolution of this parameter and the influence of the introduction of a portable gamma camera. A retrospective study was conducted using a prospective database of 754 patients who had undergone a sentinel lymph node biopsy between January 2003 and December 2011. The technique was mixed in the starting period and subsequently was performed with radiotracer intra-peritumorally administered the day before of the surgery. Until October 2009, excision of the sentinel node was guided by a probe. After that date, a portable gamma camera was introduced for intrasurgical detection. The SN was biopsied in 725 out of the 754 patients studied. The resulting technique global effectiveness was 96.2%. In accordance with the year of the surgical intervention, the identification percentage was 93.5% in 2003, 88.7% in 2004, 94.3% in 2005, 95.7% in 2006, 93.3% in 2007, 98.8% in 2008, 97.1% in 2009 and 99.1% in 2010 and 2011. There was a significant difference in the proportion of identification before and after the incorporation of the portable gamma camera of 4.6% (95% CI of the difference 2-7.2%, P = 0.0037). The percentage of global identification exceeds the recommended level following the current guidelines. Chronologically, the improvement for this parameter during the study period has been observed. These data suggest that the incorporation of a portable gamma camera had an important role. Copyright © 2013 Elsevier España, S.L. and SEMNIM. All rights reserved.

Suppressing the image smear of the vibration modulation transfer function for remote-sensing optical cameras.

PubMed

Li, Jin; Liu, Zilong; Liu, Si

2017-02-20

In on-board photographing processes of satellite cameras, the platform vibration can generate image motion, distortion, and smear, which seriously affect the image quality and image positioning. In this paper, we create a mathematical model of a vibrating modulate transfer function (VMTF) for a remote-sensing camera. The total MTF of a camera is reduced by the VMTF, which means the image quality is degraded. In order to avoid the degeneration of the total MTF caused by vibrations, we use an Mn-20Cu-5Ni-2Fe (M2052) manganese copper alloy material to fabricate a vibration-isolation mechanism (VIM). The VIM can transform platform vibration energy into irreversible thermal energy with its internal twin crystals structure. Our experiment shows the M2052 manganese copper alloy material is good enough to suppress image motion below 125 Hz, which is the vibration frequency of satellite platforms. The camera optical system has a higher MTF after suppressing the vibration of the M2052 material than before.

The Effect of Camera Angle and Image Size on Source Credibility and Interpersonal Attraction.

ERIC Educational Resources Information Center

McCain, Thomas A.; Wakshlag, Jacob J.

The purpose of this study was to examine the effects of two nonverbal visual variables (camera angle and image size) on variables developed in a nonmediated context (source credibility and interpersonal attraction). Camera angle and image size were manipulated in eight video taped television newscasts which were subsequently presented to eight…

Measurement of total-body cobalt-57 vitamin B12 absorption with a gamma camera.

PubMed

Cardarelli, J A; Slingerland, D W; Burrows, B A; Miller, A

1985-08-01

Previously described techniques for the measurement of the absorption of [57Co]vitamin B12 by total-body counting have required an iron room equipped with scanning or multiple detectors. The present study uses simplifying modifications which make the technique more available and include the use of static geometry, the measurement of body thickness to correct for attenuation, a simple formula to convert the capsule-in-air count to a 100% absorption count, and finally the use of an adequately shielded gamma camera obviating the need of an iron room.

Investigation of runaway electron dissipation in DIII-D using a gamma ray imager

NASA Astrophysics Data System (ADS)

Lvovskiy, A.; Paz-Soldan, C.; Eidietis, N.; Pace, D.; Taussig, D.

2017-10-01

We report the findings of a novel gamma ray imager (GRI) to study runaway electron (RE) dissipation in the quiescent regime on the DIII-D tokamak. The GRI measures the bremsstrahlung emission by RE providing information on RE energy spectrum and distribution across a poloidal cross-section. It consists of a lead pinhole camera illuminating a matrix of BGO detectors placed in the DIII-D mid-plane. The number of detectors was recently doubled to provide better spatial resolution and additional detector shielding was implemented to reduce un-collimated gamma flux and increase single-to-noise ratio. Under varying loop voltage, toroidal magnetic field and plasma density, a non-monotonic RE distribution function has been revealed as a result of the interplay between electric field, synchrotron radiation and collisional damping. A fraction of the high-energy RE population grows forming a bump at the RE distribution function while synchrotron radiation decreases. A possible destabilizing effect of Parail-Pogutse instability on the RE population will be also discussed. Work supported by the US DOE under DE-FC02-04ER54698.

A simultaneous beta and coincidence-gamma imaging system for plant leaves

NASA Astrophysics Data System (ADS)

Ranjbar, Homayoon; Wen, Jie; Mathews, Aswin J.; Komarov, Sergey; Wang, Qiang; Li, Ke; O'Sullivan, Joseph A.; Tai, Yuan-Chuan

2016-05-01

Positron emitting isotopes, such as 11C, 13N, and 18F, can be used to label molecules. The tracers, such as 11CO2, are delivered to plants to study their biological processes, particularly metabolism and photosynthesis, which may contribute to the development of plants that have a higher yield of crops and biomass. Measurements and resulting images from PET scanners are not quantitative in young plant structures or in plant leaves due to poor positron annihilation in thin objects. To address this problem we have designed, assembled, modeled, and tested a nuclear imaging system (simultaneous beta-gamma imager). The imager can simultaneously detect positrons ({β+} ) and coincidence-gamma rays (γ). The imaging system employs two planar detectors; one is a regular gamma detector which has a LYSO crystal array, and the other is a phoswich detector which has an additional BC-404 plastic scintillator for beta detection. A forward model for positrons is proposed along with a joint image reconstruction formulation to utilize the beta and coincidence-gamma measurements for estimating radioactivity distribution in plant leaves. The joint reconstruction algorithm first reconstructs beta and gamma images independently to estimate the thickness component of the beta forward model and afterward jointly estimates the radioactivity distribution in the object. We have validated the physics model and reconstruction framework through a phantom imaging study and imaging a tomato leaf that has absorbed 11CO2. The results demonstrate that the simultaneously acquired beta and coincidence-gamma data, combined with our proposed joint reconstruction algorithm, improved the quantitative accuracy of estimating radioactivity distribution in thin objects such as leaves. We used the structural similarity (SSIM) index for comparing the leaf images from the simultaneous beta-gamma imager with the ground truth image. The jointly reconstructed images yield SSIM indices of 0.69 and 0.63, whereas the

A simultaneous beta and coincidence-gamma imaging system for plant leaves.

PubMed

Ranjbar, Homayoon; Wen, Jie; Mathews, Aswin J; Komarov, Sergey; Wang, Qiang; Li, Ke; O'Sullivan, Joseph A; Tai, Yuan-Chuan

2016-05-07

Positron emitting isotopes, such as (11)C, (13)N, and (18)F, can be used to label molecules. The tracers, such as (11)CO2, are delivered to plants to study their biological processes, particularly metabolism and photosynthesis, which may contribute to the development of plants that have a higher yield of crops and biomass. Measurements and resulting images from PET scanners are not quantitative in young plant structures or in plant leaves due to poor positron annihilation in thin objects. To address this problem we have designed, assembled, modeled, and tested a nuclear imaging system (simultaneous beta-gamma imager). The imager can simultaneously detect positrons ([Formula: see text]) and coincidence-gamma rays (γ). The imaging system employs two planar detectors; one is a regular gamma detector which has a LYSO crystal array, and the other is a phoswich detector which has an additional BC-404 plastic scintillator for beta detection. A forward model for positrons is proposed along with a joint image reconstruction formulation to utilize the beta and coincidence-gamma measurements for estimating radioactivity distribution in plant leaves. The joint reconstruction algorithm first reconstructs beta and gamma images independently to estimate the thickness component of the beta forward model and afterward jointly estimates the radioactivity distribution in the object. We have validated the physics model and reconstruction framework through a phantom imaging study and imaging a tomato leaf that has absorbed (11)CO2. The results demonstrate that the simultaneously acquired beta and coincidence-gamma data, combined with our proposed joint reconstruction algorithm, improved the quantitative accuracy of estimating radioactivity distribution in thin objects such as leaves. We used the structural similarity (SSIM) index for comparing the leaf images from the simultaneous beta-gamma imager with the ground truth image. The jointly reconstructed images yield SSIM indices of 0

Development of a three-layer phoswich alpha-beta-gamma imaging detector

NASA Astrophysics Data System (ADS)

Yamamoto, Seiichi; Ishibashi, Hiroyuki

2015-06-01

For radiation monitoring at the sites of such nuclear power plant accidents as Fukushima Daiichi, radiation detectors are needed not only for gamma photons but also for alpha and beta particles because some nuclear fission products emit beta particles and gamma photons and some nuclear fuels contain plutonium that emits alpha particles. In some applications, imaging detectors are required to detect the distribution of plutonium particles that emit alpha particles and radiocesium in foods that emits beta particles and gamma photons. To solve these requirements, we developed an imaging detector that can measure the distribution of alpha and beta particles as well as gamma photons. The imaging detector consists of three-layer scintillators optically coupled to each other and to a position sensitive photomultiplier tube (PSPMT). The first layer, which is made of a thin plastic scintillator (decay time: 5 ns), detects alpha particles. The second layer, which is made of a thin Gd2SiO5 (GSO) scintillator with 1.5 mol% Ce (decay time: 35 ns), detects beta particles. The third layer made of a thin GSO scintillator with 0.4 mol% Ce (decay time: 70 ns) detects gamma photons. Using pulse shape discrimination, the images of these layers can be separated. The position information is calculated by the Anger principle from 8×8 anode signals from the PSPMT. The images for the alpha and beta particles and the gamma photons are individually formed by the pulse shape discriminations for each layer. We detected alpha particle images in the first layer and beta particle images in the second layer. Gamma photon images were detected in the second and third layers. The spatial resolution for the alpha and beta particles was 1.25 mm FWHM and less than 2 mm FWHM for the gamma photons. We conclude that our developed alpha-beta-gamma imaging detector is promising for imaging applications not only for the environmental monitoring of radionuclides but also for medical and molecular imaging.

Compton camera study for high efficiency SPECT and benchmark with Anger system

NASA Astrophysics Data System (ADS)

Fontana, M.; Dauvergne, D.; Létang, J. M.; Ley, J.-L.; Testa, É.

2017-12-01

Single photon emission computed tomography (SPECT) is at present one of the major techniques for non-invasive diagnostics in nuclear medicine. The clinical routine is mostly based on collimated cameras, originally proposed by Hal Anger. Due to the presence of mechanical collimation, detection efficiency and energy acceptance are limited and fixed by the system’s geometrical features. In order to overcome these limitations, the application of Compton cameras for SPECT has been investigated for several years. In this study we compare a commercial SPECT-Anger device, the General Electric HealthCare Infinia system with a High Energy General Purpose (HEGP) collimator, and the Compton camera prototype under development by the French collaboration CLaRyS, through Monte Carlo simulations (GATE—GEANT4 Application for Tomographic Emission—version 7.1 and GEANT4 version 9.6, respectively). Given the possible introduction of new radio-emitters at higher energies intrinsically allowed by the Compton camera detection principle, the two detectors are exposed to point-like sources at increasing primary gamma energies, from actual isotopes already suggested for nuclear medicine applications. The Compton camera prototype is first characterized for SPECT application by studying the main parameters affecting its imaging performance: detector energy resolution and random coincidence rate. The two detector performances are then compared in terms of radial event distribution, detection efficiency and final image, obtained by gamma transmission analysis for the Anger system, and with an iterative List Mode-Maximum Likelihood Expectation Maximization (LM-MLEM) algorithm for the Compton reconstruction. The results show for the Compton camera a detection efficiency increased by a factor larger than an order of magnitude with respect to the Anger camera, associated with an enhanced spatial resolution for energies beyond 500 keV. We discuss the advantages of Compton camera application

Integration of image capture and processing: beyond single-chip digital camera

NASA Astrophysics Data System (ADS)

Lim, SukHwan; El Gamal, Abbas

2001-05-01

An important trend in the design of digital cameras is the integration of capture and processing onto a single CMOS chip. Although integrating the components of a digital camera system onto a single chip significantly reduces system size and power, it does not fully exploit the potential advantages of integration. We argue that a key advantage of integration is the ability to exploit the high speed imaging capability of CMOS image senor to enable new applications such as multiple capture for enhancing dynamic range and to improve the performance of existing applications such as optical flow estimation. Conventional digital cameras operate at low frame rates and it would be too costly, if not infeasible, to operate their chips at high frame rates. Integration solves this problem. The idea is to capture images at much higher frame rates than he standard frame rate, process the high frame rate data on chip, and output the video sequence and the application specific data at standard frame rate. This idea is applied to optical flow estimation, where significant performance improvements are demonstrate over methods using standard frame rate sequences. We then investigate the constraints on memory size and processing power that can be integrated with a CMOS image sensor in a 0.18 micrometers process and below. We show that enough memory and processing power can be integrated to be able to not only perform the functions of a conventional camera system but also to perform applications such as real time optical flow estimation.

Alternative images for perpendicular parking : a usability test of a multi-camera parking assistance system.

DOT National Transportation Integrated Search

2004-10-01

The parking assistance system evaluated consisted of four outward facing cameras whose images could be presented on a monitor on the center console. The images presented varied in the location of the virtual eye point of the camera (the height above ...

Camera system resolution and its influence on digital image correlation

DOE PAGES

Reu, Phillip L.; Sweatt, William; Miller, Timothy; ...

2014-09-21

Digital image correlation (DIC) uses images from a camera and lens system to make quantitative measurements of the shape, displacement, and strain of test objects. This increasingly popular method has had little research on the influence of the imaging system resolution on the DIC results. This paper investigates the entire imaging system and studies how both the camera and lens resolution influence the DIC results as a function of the system Modulation Transfer Function (MTF). It will show that when making spatial resolution decisions (including speckle size) the resolution limiting component should be considered. A consequence of the loss ofmore » spatial resolution is that the DIC uncertainties will be increased. This is demonstrated using both synthetic and experimental images with varying resolution. The loss of image resolution and DIC accuracy can be compensated for by increasing the subset size, or better, by increasing the speckle size. The speckle-size and spatial resolution are now a function of the lens resolution rather than the more typical assumption of the pixel size. The study will demonstrate the tradeoffs associated with limited lens resolution.« less

Occult Breast Cancer: Scintimammography with High-Resolution Breast-specific Gamma Camera in Women at High Risk for Breast Cancer

DOE Office of Scientific and Technical Information (OSTI.GOV)

Rachel F. Brem; Jocelyn A. Rapelyea; , Gilat Zisman

2005-08-01

To prospectively evaluate a high-resolution breast-specific gamma camera for depicting occult breast cancer in women at high risk for breast cancer but with normal mammographic and physical examination findings. MATERIALS AND METHODS: Institutional Review Board approval and informed consent were obtained. The study was HIPAA compliant. Ninety-four high-risk women (age range, 36-78 years; mean, 55 years) with normal mammographic (Breast Imaging Reporting and Data System [BI-RADS] 1 or 2) and physical examination findings were evaluated with scintimammography. After injection with 25-30 mCi (925-1110 MBq) of technetium 99m sestamibi, patients were imaged with a high-resolution small-field-of-view breast-specific gamma camera in craniocaudalmore » and mediolateral oblique projections. Scintimammograms were prospectively classified according to focal radiotracer uptake as normal (score of 1), with no focal or diffuse uptake; benign (score of 2), with minimal patchy uptake; probably benign (score of 3), with scattered patchy uptake; probably abnormal (score of 4), with mild focal radiotracer uptake; and abnormal (score of 5), with marked focal radiotracer uptake. Mammographic breast density was categorized according to BI-RADS criteria. Patients with normal scintimammograms (scores of 1, 2, or 3) were followed up for 1 year with an annual mammogram, physical examination, and repeat scintimammography. Patients with abnormal scintimammograms (scores of 4 or 5) underwent ultrasonography (US), and those with focal hypoechoic lesions underwent biopsy. If no lesion was found during US, patients were followed up with scintimammography. Specific pathologic findings were compared with scintimammographic findings. RESULTS: Of 94 women, 78 (83%) had normal scintimammograms (score of 1, 2, or 3) at initial examination and 16 (17%) had abnormal scintimammograms (score of 4 or 5). Fourteen (88%) of the 16 patients had either benign findings at biopsy or no focal abnormality at US

In vitro near-infrared imaging of occlusal dental caries using germanium enhanced CMOS camera.

PubMed

Lee, Chulsung; Darling, Cynthia L; Fried, Daniel

2010-03-01

The high transparency of dental enamel in the near-infrared (NIR) at 1310-nm can be exploited for imaging dental caries without the use of ionizing radiation. The objective of this study was to determine whether the lesion contrast derived from NIR transillumination can be used to estimate lesion severity. Another aim was to compare the performance of a new Ge enhanced complementary metal-oxide-semiconductor (CMOS) based NIR imaging camera with the InGaAs focal plane array (FPA). Extracted human teeth (n=52) with natural occlusal caries were imaged with both cameras at 1310-nm and the image contrast between sound and carious regions was calculated. After NIR imaging, teeth were sectioned and examined using more established methods, namely polarized light microscopy (PLM) and transverse microradiography (TMR) to calculate lesion severity. Lesions were then classified into 4 categories according to the lesion severity. Lesion contrast increased significantly with lesion severity for both cameras (p<0.05). The Ge enhanced CMOS camera equipped with the larger array and smaller pixels yielded higher contrast values compared with the smaller InGaAs FPA (p<0.01). Results demonstrate that NIR lesion contrast can be used to estimate lesion severity.

Monitoring Tc dynamics in a bioreduced sediment: an investigation with gamma camera imaging of (99m)Tc-pertechnetate and (99m)Tc-DTPA.

PubMed

Vandehey, Nicholas T; O'Neil, James P; Slowey, Aaron J; Boutchko, Rostyslav; Druhan, Jennifer L; Moses, William W; Nico, Peter S

2012-11-20

We demonstrate the utility of nuclear medical imaging technologies and a readily available radiotracer, [(99m)Tc]TcO(4)(-), for the noninvasive monitoring of Fe(II) production in acetate-stimulated sediments from Old Rifle, CO, USA. Microcosms consisting of sediment in artificial groundwater media amended with acetate were probed by repeated injection of radiotracer over three weeks. Gamma camera imaging was used to noninvasively quantify the rate and extent of [(99m)Tc]TcO(4)(-) partitioning from solution to sediment. Aqueous Fe(II) and sediment-associated Fe(II) were also measured and correlated with the observed tracer behavior. For each injection of tracer, curves of (99m)Tc concentration in solution vs time were fitted to an analytic function that accounts for both the observed rate of sedimentation as well as the rate of (99m)Tc association with the sediment. The rate and extent of (99m)Tc association with the biostimulated sediment correlated well with the production of Fe(II), and a mechanism of [(99m)Tc]TcO(4)(-) reduction via reaction with surface-bound Fe(II) to form an immobile Tc(IV) species was inferred. After three weeks of bioreduction, a subset of microcosms was aerated in order to reoxidize the Fe(II) to Fe(III), which also destroyed the affinity of the [(99m)Tc]TcO(4)(-) for the sediments. However, within 3 days postoxidation, the rate of Tc(VII) reduction was faster than immediately before oxidation implying a rapid return to more extensive bioreduction. Furthermore, aeration soon after a tracer injection showed that sediment-bound Tc(IV) is rapidly resolubilized to Tc(VII). In contrast to the [(99m)Tc]TcO(4)(-), a second commercially available tracer, (99m)Tc-DTPA (diethylenetriaminepentaacetic acid), had minimal association with sediment in both controls and biostimulated sediments. These experiments show the promise of [(99m)Tc]TcO(4)(-) and (99m)Tc-DTPA as noninvasive imaging probes for a redox-sensitive radiotracer and a conservative flow

Gamma-camera 18F-FDG PET in diagnosis and staging of patients presenting with suspected lung cancer and comparison with dedicated PET.

PubMed

Oturai, Peter S; Mortensen, Jann; Enevoldsen, Henriette; Eigtved, Annika; Backer, Vibeke; Olesen, Knud P; Nielsen, Henrik W; Hansen, Hanne; Stentoft, Poul; Friberg, Lars

2004-08-01

It is not clear whether high-quality coincidence gamma-PET (gPET) cameras can provide clinical data comparable with data obtained with dedicated PET (dPET) cameras in the primary diagnostic work-up of patients with suspected lung cancer. This study focuses on 2 main issues: direct comparison between foci resolved with the 2 different PET scanners and the diagnostic accuracy compared with final diagnosis determined by the combined information from all other investigations and clinical follow-up. Eighty-six patients were recruited to this study through a routine diagnostic program. They all had changes on their chest radiographs, suggesting malignant lung tumor. In addition to the standard diagnostic program, each patient had 2 PET scans that were performed on the same day. After administration of 419 MBq (range = 305-547 MBq) (18)F-FDG, patients were scanned in a dedicated PET scanner about 1 h after FDG administration and in a dual-head coincidence gamma-camera about 3 h after tracer injection. Images from the 2 scans were evaluated in a blinded set-up and compared with the final outcome. Malignant intrathoracic disease was found in 52 patients, and 47 patients had primary lung cancers. dPET detected all patients as having malignancies (sensitivity, 100%; specificity, 50%), whereas gPET missed one patient (sensitivity, 98%; specificity, 56%). For evaluating regional lymph node involvement, sensitivity and specificity rates were 78% and 84% for dPET and 61% and 90% for gPET, respectively. When comparing the 2 PET techniques with clinical tumor stage (TNM), full agreement was obtained in 64% of the patients (Cohen's kappa = 0.56). Comparing categorization of the patients into clinical relevant stages (no malignancy/malignancy suitable for treatment with curative intent/nontreatable malignancy), resulted in full agreement in 81% (Cohen's kappa = 0.71) of patients. Comparing results from a recent generation of gPET cameras obtained about 2 h later than those of d

Image dissector camera system study

NASA Technical Reports Server (NTRS)

Howell, L.

1984-01-01

Various aspects of a rendezvous and docking system using an image dissector detector as compared to a GaAs detector were discussed. Investigation into a gimbled scanning system is also covered and the measured video response curves from the image dissector camera are presented. Rendezvous will occur at ranges greater than 100 meters. The maximum range considered was 1000 meters. During docking, the range, range-rate, angle, and angle-rate to each reflector on the satellite must be measured. Docking range will be from 3 to 100 meters. The system consists of a CW laser diode transmitter and an image dissector receiver. The transmitter beam is amplitude modulated with three sine wave tones for ranging. The beam is coaxially combined with the receiver beam. Mechanical deflection of the transmitter beam, + or - 10 degrees in both X and Y, can be accomplished before or after it is combined with the receiver beam. The receiver will have a field-of-view (FOV) of 20 degrees and an instantaneous field-of-view (IFOV) of two milliradians (mrad) and will be electronically scanned in the image dissector. The increase in performance obtained from the GaAs photocathode is not needed to meet the present performance requirements.

Camera sensor arrangement for crop/weed detection accuracy in agronomic images.

PubMed

Romeo, Juan; Guerrero, José Miguel; Montalvo, Martín; Emmi, Luis; Guijarro, María; Gonzalez-de-Santos, Pablo; Pajares, Gonzalo

2013-04-02

In Precision Agriculture, images coming from camera-based sensors are commonly used for weed identification and crop line detection, either to apply specific treatments or for vehicle guidance purposes. Accuracy of identification and detection is an important issue to be addressed in image processing. There are two main types of parameters affecting the accuracy of the images, namely: (a) extrinsic, related to the sensor's positioning in the tractor; (b) intrinsic, related to the sensor specifications, such as CCD resolution, focal length or iris aperture, among others. Moreover, in agricultural applications, the uncontrolled illumination, existing in outdoor environments, is also an important factor affecting the image accuracy. This paper is exclusively focused on two main issues, always with the goal to achieve the highest image accuracy in Precision Agriculture applications, making the following two main contributions: (a) camera sensor arrangement, to adjust extrinsic parameters and (b) design of strategies for controlling the adverse illumination effects.

A novel SPECT camera for molecular imaging of the prostate

NASA Astrophysics Data System (ADS)

Cebula, Alan; Gilland, David; Su, Li-Ming; Wagenaar, Douglas; Bahadori, Amir

2011-10-01

The objective of this work is to develop an improved SPECT camera for dedicated prostate imaging. Complementing the recent advancements in agents for molecular prostate imaging, this device has the potential to assist in distinguishing benign from aggressive cancers, to improve site-specific localization of cancer, to improve accuracy of needle-guided prostate biopsy of cancer sites, and to aid in focal therapy procedures such as cryotherapy and radiation. Theoretical calculations show that the spatial resolution/detection sensitivity of the proposed SPECT camera can rival or exceed 3D PET and further signal-to-noise advantage is attained with the better energy resolution of the CZT modules. Based on photon transport simulation studies, the system has a reconstructed spatial resolution of 4.8 mm with a sensitivity of 0.0001. Reconstruction of a simulated prostate distribution demonstrates the focal imaging capability of the system.

Application of low-noise CID imagers in scientific instrumentation cameras

NASA Astrophysics Data System (ADS)

Carbone, Joseph; Hutton, J.; Arnold, Frank S.; Zarnowski, Jeffrey J.; Vangorden, Steven; Pilon, Michael J.; Wadsworth, Mark V.

1991-07-01

CIDTEC has developed a PC-based instrumentation camera incorporating a preamplifier per row CID imager and a microprocessor/LCA camera controller. The camera takes advantage of CID X-Y addressability to randomly read individual pixels and potentially overlapping pixel subsets in true nondestructive (NDRO) as well as destructive readout modes. Using an oxy- nitride fabricated CID and the NDRO readout technique, pixel full well and noise levels of approximately 1*10(superscript 6) and 40 electrons, respectively, were measured. Data taken from test structures indicates noise levels (which appear to be 1/f limited) can be reduced by a factor of two by eliminating the nitride under the preamplifier gate. Due to software programmability, versatile readout capabilities, wide dynamic range, and extended UV/IR capability, this camera appears to be ideally suited for use in spectroscopy and other scientific applications.

Real-time imaging of methane gas leaks using a single-pixel camera.

PubMed

Gibson, Graham M; Sun, Baoqing; Edgar, Matthew P; Phillips, David B; Hempler, Nils; Maker, Gareth T; Malcolm, Graeme P A; Padgett, Miles J

2017-02-20

We demonstrate a camera which can image methane gas at video rates, using only a single-pixel detector and structured illumination. The light source is an infrared laser diode operating at 1.651μm tuned to an absorption line of methane gas. The light is structured using an addressable micromirror array to pattern the laser output with a sequence of Hadamard masks. The resulting backscattered light is recorded using a single-pixel InGaAs detector which provides a measure of the correlation between the projected patterns and the gas distribution in the scene. Knowledge of this correlation and the patterns allows an image to be reconstructed of the gas in the scene. For the application of locating gas leaks the frame rate of the camera is of primary importance, which in this case is inversely proportional to the square of the linear resolution. Here we demonstrate gas imaging at ~25 fps while using 256 mask patterns (corresponding to an image resolution of 16×16). To aid the task of locating the source of the gas emission, we overlay an upsampled and smoothed image of the low-resolution gas image onto a high-resolution color image of the scene, recorded using a standard CMOS camera. We demonstrate for an illumination of only 5mW across the field-of-view imaging of a methane gas leak of ~0.2 litres/minute from a distance of ~1 metre.

Autofluorescence imaging of basal cell carcinoma by smartphone RGB camera

NASA Astrophysics Data System (ADS)

Lihachev, Alexey; Derjabo, Alexander; Ferulova, Inesa; Lange, Marta; Lihacova, Ilze; Spigulis, Janis

2015-12-01

The feasibility of smartphones for in vivo skin autofluorescence imaging has been investigated. Filtered autofluorescence images from the same tissue area were periodically captured by a smartphone RGB camera with subsequent detection of fluorescence intensity decreasing at each image pixel for further imaging the planar distribution of those values. The proposed methodology was tested clinically with 13 basal cell carcinoma and 1 atypical nevus. Several clinical cases and potential future applications of the smartphone-based technique are discussed.

Autofluorescence imaging of basal cell carcinoma by smartphone RGB camera.

PubMed

Lihachev, Alexey; Derjabo, Alexander; Ferulova, Inesa; Lange, Marta; Lihacova, Ilze; Spigulis, Janis

2015-01-01

The feasibility of smartphones for in vivo skin autofluorescence imaging has been investigated. Filtered autofluorescence images from the same tissue area were periodically captured by a smartphone RGB camera with subsequent detection of fluorescence intensity decreasing at each image pixel for further imaging the planar distribution of those values. The proposed methodology was tested clinically with 13 basal cell carcinoma and 1 atypical nevus. Several clinical cases and potential future applications of the smartphone-based technique are discussed.

Constructing a Database from Multiple 2D Images for Camera Pose Estimation and Robot Localization

NASA Technical Reports Server (NTRS)

Wolf, Michael; Ansar, Adnan I.; Brennan, Shane; Clouse, Daniel S.; Padgett, Curtis W.

2012-01-01

The LMDB (Landmark Database) Builder software identifies persistent image features (landmarks) in a scene viewed multiple times and precisely estimates the landmarks 3D world positions. The software receives as input multiple 2D images of approximately the same scene, along with an initial guess of the camera poses for each image, and a table of features matched pair-wise in each frame. LMDB Builder aggregates landmarks across an arbitrarily large collection of frames with matched features. Range data from stereo vision processing can also be passed to improve the initial guess of the 3D point estimates. The LMDB Builder aggregates feature lists across all frames, manages the process to promote selected features to landmarks, and iteratively calculates the 3D landmark positions using the current camera pose estimations (via an optimal ray projection method), and then improves the camera pose estimates using the 3D landmark positions. Finally, it extracts image patches for each landmark from auto-selected key frames and constructs the landmark database. The landmark database can then be used to estimate future camera poses (and therefore localize a robotic vehicle that may be carrying the cameras) by matching current imagery to landmark database image patches and using the known 3D landmark positions to estimate the current pose.

The upgrade of the H.E.S.S. cameras

NASA Astrophysics Data System (ADS)

Giavitto, Gianluca; Ashton, Terry; Balzer, Arnim; Berge, David; Brun, Francois; Chaminade, Thomas; Delagnes, Eric; Fontaine, Gerard; Füßling, Matthias; Giebels, Berrie; Glicenstein, Jean-Francois; Gräber, Tobias; Hinton, Jim; Jahnke, Albert; Klepser, Stefan; Kossatz, Marko; Kretzschmann, Axel; Lefranc, Valentin; Leich, Holger; Lüdecke, Hartmut; Lypova, Iryna; Manigot, Pascal; Marandon, Vincent; Moulin, Emmanuel; Naurois, Mathieu de; Nayman, Patrick; Ohm, Stefan; Penno, Marek; Ross, Duncan; Salek, David; Schade, Markus; Schwab, Thomas; Simoni, Rachel; Stegmann, Christian; Steppa, Constantin; Thornhill, Julian; Toussnel, Francois

2017-12-01

The High Energy Stereoscopic System (HESS) is an array of imaging atmospheric Cherenkov telescopes (IACTs) located in the Khomas highland in Namibia. It was built to detect Very High Energy (VHE > 100 GeV) cosmic gamma rays. Since 2003, HESS has discovered the majority of the known astrophysical VHE gamma-ray sources, opening a new observational window on the extreme non-thermal processes at work in our universe. HESS consists of four 12-m diameter Cherenkov telescopes (CT1-4), which started data taking in 2002, and a larger 28-m telescope (CT5), built in 2012, which lowers the energy threshold of the array to 30 GeV . The cameras of CT1-4 are currently undergoing an extensive upgrade, with the goals of reducing their failure rate, reducing their readout dead time and improving the overall performance of the array. The entire camera electronics has been renewed from ground-up, as well as the power, ventilation and pneumatics systems, and the control and data acquisition software. Only the PMTs and their HV supplies have been kept from the original cameras. Novel technical solutions have been introduced, which will find their way into some of the Cherenkov cameras foreseen for the next-generation Cherenkov Telescope Array (CTA) observatory. In particular, the camera readout system is the first large-scale system based on the analog memory chip NECTAr, which was designed for CTA cameras. The camera control subsystems and the control software framework also pursue an innovative design, exploiting cutting-edge hardware and software solutions which excel in performance, robustness and flexibility. The CT1 camera has been upgraded in July 2015 and is currently taking data; CT2-4 have been upgraded in fall 2016. Together they will assure continuous operation of HESS at its full sensitivity until and possibly beyond the advent of CTA. This contribution describes the design, the testing and the in-lab and on-site performance of all components of the newly upgraded HESS

Effects of frame rate and image resolution on pulse rate measured using multiple camera imaging photoplethysmography

NASA Astrophysics Data System (ADS)

Blackford, Ethan B.; Estepp, Justin R.

2015-03-01

Non-contact, imaging photoplethysmography uses cameras to facilitate measurements including pulse rate, pulse rate variability, respiration rate, and blood perfusion by measuring characteristic changes in light absorption at the skin's surface resulting from changes in blood volume in the superficial microvasculature. Several factors may affect the accuracy of the physiological measurement including imager frame rate, resolution, compression, lighting conditions, image background, participant skin tone, and participant motion. Before this method can gain wider use outside basic research settings, its constraints and capabilities must be well understood. Recently, we presented a novel approach utilizing a synchronized, nine-camera, semicircular array backed by measurement of an electrocardiogram and fingertip reflectance photoplethysmogram. Twenty-five individuals participated in six, five-minute, controlled head motion artifact trials in front of a black and dynamic color backdrop. Increasing the input channel space for blind source separation using the camera array was effective in mitigating error from head motion artifact. Herein we present the effects of lower frame rates at 60 and 30 (reduced from 120) frames per second and reduced image resolution at 329x246 pixels (one-quarter of the original 658x492 pixel resolution) using bilinear and zero-order downsampling. This is the first time these factors have been examined for a multiple imager array and align well with previous findings utilizing a single imager. Examining windowed pulse rates, there is little observable difference in mean absolute error or error distributions resulting from reduced frame rates or image resolution, thus lowering requirements for systems measuring pulse rate over sufficient length time windows.

Simultaneous fluoroscopic and nuclear imaging: impact of collimator choice on nuclear image quality.

PubMed

van der Velden, Sandra; Beijst, Casper; Viergever, Max A; de Jong, Hugo W A M

2017-01-01

X-ray-guided oncological interventions could benefit from the availability of simultaneously acquired nuclear images during the procedure. To this end, a real-time, hybrid fluoroscopic and nuclear imaging device, consisting of an X-ray c-arm combined with gamma imaging capability, is currently being developed (Beijst C, Elschot M, Viergever MA, de Jong HW. Radiol. 2015;278:232-238). The setup comprises four gamma cameras placed adjacent to the X-ray tube. The four camera views are used to reconstruct an intermediate three-dimensional image, which is subsequently converted to a virtual nuclear projection image that overlaps with the X-ray image. The purpose of the present simulation study is to evaluate the impact of gamma camera collimator choice (parallel hole versus pinhole) on the quality of the virtual nuclear image. Simulation studies were performed with a digital image quality phantom including realistic noise and resolution effects, with a dynamic frame acquisition time of 1 s and a total activity of 150 MBq. Projections were simulated for 3, 5, and 7 mm pinholes and for three parallel hole collimators (low-energy all-purpose (LEAP), low-energy high-resolution (LEHR) and low-energy ultra-high-resolution (LEUHR)). Intermediate reconstruction was performed with maximum likelihood expectation-maximization (MLEM) with point spread function (PSF) modeling. In the virtual projection derived therefrom, contrast, noise level, and detectability were determined and compared with the ideal projection, that is, as if a gamma camera were located at the position of the X-ray detector. Furthermore, image deformations and spatial resolution were quantified. Additionally, simultaneous fluoroscopic and nuclear images of a sphere phantom were acquired with a physical prototype system and compared with the simulations. For small hot spots, contrast is comparable for all simulated collimators. Noise levels are, however, 3 to 8 times higher in pinhole geometries than in parallel

Single-camera stereo-digital image correlation with a four-mirror adapter: optimized design and validation

NASA Astrophysics Data System (ADS)

Yu, Liping; Pan, Bing

2016-12-01

A low-cost, easy-to-implement but practical single-camera stereo-digital image correlation (DIC) system using a four-mirror adapter is established for accurate shape and three-dimensional (3D) deformation measurements. The mirrors assisted pseudo-stereo imaging system can convert a single camera into two virtual cameras, which view a specimen from different angles and record the surface images of the test object onto two halves of the camera sensor. To enable deformation measurement in non-laboratory conditions or extreme high temperature environments, an active imaging optical design, combining an actively illuminated monochromatic source with a coupled band-pass optical filter, is compactly integrated to the pseudo-stereo DIC system. The optical design, basic principles and implementation procedures of the established system for 3D profile and deformation measurements are described in detail. The effectiveness and accuracy of the established system are verified by measuring the profile of a regular cylinder surface and displacements of a translated planar plate. As an application example, the established system is used to determine the tensile strains and Poisson's ratio of a composite solid propellant specimen during stress relaxation test. Since the established single-camera stereo-DIC system only needs a single camera and presents strong robustness against variations in ambient light or the thermal radiation of a hot object, it demonstrates great potential in determining transient deformation in non-laboratory or high-temperature environments with the aid of a single high-speed camera.

Laser Imaging Video Camera Sees Through Fire, Fog, Smoke

NASA Technical Reports Server (NTRS)

2015-01-01

Under a series of SBIR contracts with Langley Research Center, inventor Richard Billmers refined a prototype for a laser imaging camera capable of seeing through fire, fog, smoke, and other obscurants. Now, Canton, Ohio-based Laser Imaging through Obscurants (LITO) Technologies Inc. is demonstrating the technology as a perimeter security system at Glenn Research Center and planning its future use in aviation, shipping, emergency response, and other fields.

Multi-frame image processing with panning cameras and moving subjects

NASA Astrophysics Data System (ADS)

Paolini, Aaron; Humphrey, John; Curt, Petersen; Kelmelis, Eric

2014-06-01

Imaging scenarios commonly involve erratic, unpredictable camera behavior or subjects that are prone to movement, complicating multi-frame image processing techniques. To address these issues, we developed three techniques that can be applied to multi-frame image processing algorithms in order to mitigate the adverse effects observed when cameras are panning or subjects within the scene are moving. We provide a detailed overview of the techniques and discuss the applicability of each to various movement types. In addition to this, we evaluated algorithm efficacy with demonstrated benefits using field test video, which has been processed using our commercially available surveillance product. Our results show that algorithm efficacy is significantly improved in common scenarios, expanding our software's operational scope. Our methods introduce little computational burden, enabling their use in real-time and low-power solutions, and are appropriate for long observation periods. Our test cases focus on imaging through turbulence, a common use case for multi-frame techniques. We present results of a field study designed to test the efficacy of these techniques under expanded use cases.

Determining fast orientation changes of multi-spectral line cameras from the primary images

NASA Astrophysics Data System (ADS)

Wohlfeil, Jürgen

2012-01-01

Fast orientation changes of airborne and spaceborne line cameras cannot always be avoided. In such cases it is essential to measure them with high accuracy to ensure a good quality of the resulting imagery products. Several approaches exist to support the orientation measurement by using optical information received through the main objective/telescope. In this article an approach is proposed that allows the determination of non-systematic orientation changes between every captured line. It does not require any additional camera hardware or onboard processing capabilities but the payload images and a rough estimate of the camera's trajectory. The approach takes advantage of the typical geometry of multi-spectral line cameras with a set of linear sensor arrays for different spectral bands on the focal plane. First, homologous points are detected within the heavily distorted images of different spectral bands. With their help a connected network of geometrical correspondences can be built up. This network is used to calculate the orientation changes of the camera with the temporal and angular resolution of the camera. The approach was tested with an extensive set of aerial surveys covering a wide range of different conditions and achieved precise and reliable results.

The Atlases of Vesta derived from Dawn Framing Camera images

NASA Astrophysics Data System (ADS)

Roatsch, T.; Kersten, E.; Matz, K.; Preusker, F.; Scholten, F.; Jaumann, R.; Raymond, C. A.; Russell, C. T.

2013-12-01

The Dawn Framing Camera acquired during its two HAMO (High Altitude Mapping Orbit) phases in 2011 and 2012 about 6,000 clear filter images with a resolution of about 60 m/pixel. We combined these images in a global ortho-rectified mosaic of Vesta (60 m/pixel resolution). Only very small areas near the northern pole were still in darkness and are missing in the mosaic. The Dawn Framing Camera also acquired about 10,000 high-resolution clear filter images (about 20 m/pixel) of Vesta during its Low Altitude Mapping Orbit (LAMO). Unfortunately, the northern part of Vesta was still in darkness during this phase, good illumination (incidence angle < 70°) was only available for 66.8 % of the surface [1]. We used the LAMO images to calculate another global mosaic of Vesta, this time with 20 m/pixel resolution. Both global mosaics were used to produce atlases of Vesta: a HAMO atlas with 15 tiles at a scale of 1:500,000 and a LAMO atlas with 30 tiles at a scale between 1:200,000 and 1:225,180. The nomenclature used in these atlases is based on names and places historically associated with the Roman goddess Vesta, and is compliant with the rules of the IAU. 65 names for geological features were already approved by the IAU, 39 additional names are currently under review. Selected examples of both atlases will be shown in this presentation. Reference: [1]Roatsch, Th., etal., High-resolution Vesta Low Altitude Mapping Orbit Atlas derived from Dawn Framing Camera images. Planetary and Space Science (2013), http://dx.doi.org/10.1016/j.pss.2013.06.024i

Exploring the feasibility of iris recognition for visible spectrum iris images obtained using smartphone camera

NASA Astrophysics Data System (ADS)

Trokielewicz, Mateusz; Bartuzi, Ewelina; Michowska, Katarzyna; Andrzejewska, Antonina; Selegrat, Monika

2015-09-01

In the age of modern, hyperconnected society that increasingly relies on mobile devices and solutions, implementing a reliable and accurate biometric system employing iris recognition presents new challenges. Typical biometric systems employing iris analysis require expensive and complicated hardware. We therefore explore an alternative way using visible spectrum iris imaging. This paper aims at answering several questions related to applying iris biometrics for images obtained in the visible spectrum using smartphone camera. Can irides be successfully and effortlessly imaged using a smartphone's built-in camera? Can existing iris recognition methods perform well when presented with such images? The main advantage of using near-infrared (NIR) illumination in dedicated iris recognition cameras is good performance almost independent of the iris color and pigmentation. Are the images obtained from smartphone's camera of sufficient quality even for the dark irides? We present experiments incorporating simple image preprocessing to find the best visibility of iris texture, followed by a performance study to assess whether iris recognition methods originally aimed at NIR iris images perform well with visible light images. To our best knowledge this is the first comprehensive analysis of iris recognition performance using a database of high-quality images collected in visible light using the smartphones flashlight together with the application of commercial off-the-shelf (COTS) iris recognition methods.

An Efficient Image Compressor for Charge Coupled Devices Camera

PubMed Central

Li, Jin; Xing, Fei; You, Zheng

2014-01-01

Recently, the discrete wavelet transforms- (DWT-) based compressor, such as JPEG2000 and CCSDS-IDC, is widely seen as the state of the art compression scheme for charge coupled devices (CCD) camera. However, CCD images project on the DWT basis to produce a large number of large amplitude high-frequency coefficients because these images have a large number of complex texture and contour information, which are disadvantage for the later coding. In this paper, we proposed a low-complexity posttransform coupled with compressing sensing (PT-CS) compression approach for remote sensing image. First, the DWT is applied to the remote sensing image. Then, a pair base posttransform is applied to the DWT coefficients. The pair base are DCT base and Hadamard base, which can be used on the high and low bit-rate, respectively. The best posttransform is selected by the l p-norm-based approach. The posttransform is considered as the sparse representation stage of CS. The posttransform coefficients are resampled by sensing measurement matrix. Experimental results on on-board CCD camera images show that the proposed approach significantly outperforms the CCSDS-IDC-based coder, and its performance is comparable to that of the JPEG2000 at low bit rate and it does not have the high excessive implementation complexity of JPEG2000. PMID:25114977

Orientation Modeling for Amateur Cameras by Matching Image Line Features and Building Vector Data

NASA Astrophysics Data System (ADS)

Hung, C. H.; Chang, W. C.; Chen, L. C.

2016-06-01

With the popularity of geospatial applications, database updating is getting important due to the environmental changes over time. Imagery provides a lower cost and efficient way to update the database. Three dimensional objects can be measured by space intersection using conjugate image points and orientation parameters of cameras. However, precise orientation parameters of light amateur cameras are not always available due to their costliness and heaviness of precision GPS and IMU. To automatize data updating, the correspondence of object vector data and image may be built to improve the accuracy of direct georeferencing. This study contains four major parts, (1) back-projection of object vector data, (2) extraction of image feature lines, (3) object-image feature line matching, and (4) line-based orientation modeling. In order to construct the correspondence of features between an image and a building model, the building vector features were back-projected onto the image using the initial camera orientation from GPS and IMU. Image line features were extracted from the imagery. Afterwards, the matching procedure was done by assessing the similarity between the extracted image features and the back-projected ones. Then, the fourth part utilized line features in orientation modeling. The line-based orientation modeling was performed by the integration of line parametric equations into collinearity condition equations. The experiment data included images with 0.06 m resolution acquired by Canon EOS Mark 5D II camera on a Microdrones MD4-1000 UAV. Experimental results indicate that 2.1 pixel accuracy may be reached, which is equivalent to 0.12 m in the object space.

SCC500: next-generation infrared imaging camera core products with highly flexible architecture for unique camera designs

NASA Astrophysics Data System (ADS)

Rumbaugh, Roy N.; Grealish, Kevin; Kacir, Tom; Arsenault, Barry; Murphy, Robert H.; Miller, Scott

2003-09-01

A new 4th generation MicroIR architecture is introduced as the latest in the highly successful Standard Camera Core (SCC) series by BAE SYSTEMS to offer an infrared imaging engine with greatly reduced size, weight, power, and cost. The advanced SCC500 architecture provides great flexibility in configuration to include multiple resolutions, an industry standard Real Time Operating System (RTOS) for customer specific software application plug-ins, and a highly modular construction for unique physical and interface options. These microbolometer based camera cores offer outstanding and reliable performance over an extended operating temperature range to meet the demanding requirements of real-world environments. A highly integrated lens and shutter is included in the new SCC500 product enabling easy, drop-in camera designs for quick time-to-market product introductions.

Astatine-211 imaging by a Compton camera for targeted radiotherapy.

PubMed

Nagao, Yuto; Yamaguchi, Mitsutaka; Watanabe, Shigeki; Ishioka, Noriko S; Kawachi, Naoki; Watabe, Hiroshi

2018-05-24

Astatine-211 is a promising radionuclide for targeted radiotherapy. It is required to image the distribution of targeted radiotherapeutic agents in a patient's body for optimization of treatment strategies. We proposed to image 211 At with high-energy photons to overcome some problems in conventional planar or single-photon emission computed tomography imaging. We performed an imaging experiment of a point-like 211 At source using a Compton camera, and demonstrated the capability of imaging 211 At with the high-energy photons for the first time. Copyright © 2018 Elsevier Ltd. All rights reserved.