[Techniques for pixel response nonuniformity correction of CCD in interferential imaging spectrometer].

PubMed

Yao, Tao; Yin, Shi-Min; Xiangli, Bin; Lü, Qun-Bo

2010-06-01

Based on in-depth analysis of the relative radiation scaling theorem and acquired scaling data of pixel response nonuniformity correction of CCD (charge-coupled device) in spaceborne visible interferential imaging spectrometer, a pixel response nonuniformity correction method of CCD adapted to visible and infrared interferential imaging spectrometer system was studied out, and it availably resolved the engineering technical problem of nonuniformity correction in detector arrays for interferential imaging spectrometer system. The quantitative impact of CCD nonuniformity on interferogram correction and recovery spectrum accuracy was given simultaneously. Furthermore, an improved method with calibration and nonuniformity correction done after the instrument is successfully assembled was proposed. The method can save time and manpower. It can correct nonuniformity caused by other reasons in spectrometer system besides CCD itself's nonuniformity, can acquire recalibration data when working environment is changed, and can also more effectively improve the nonuniformity calibration accuracy of interferential imaging

A Pipeline Tool for CCD Image Processing

NASA Astrophysics Data System (ADS)

Bell, Jon F.; Young, Peter J.; Roberts, William H.; Sebo, Kim M.

MSSSO is part of a collaboration developing a wide field imaging CCD mosaic (WFI). As part of this project, we have developed a GUI based pipeline tool that is an integrated part of MSSSO's CICADA data acquisition environment and processes CCD FITS images as they are acquired. The tool is also designed to run as a stand alone program to process previously acquired data. IRAF tasks are used as the central engine, including the new NOAO mscred package for processing multi-extension FITS files. The STScI OPUS pipeline environment may be used to manage data and process scheduling. The Motif GUI was developed using SUN Visual Workshop. C++ classes were written to facilitate launching of IRAF and OPUS tasks. While this first version implements calibration processing up to and including flat field corrections, there is scope to extend it to other processing.

Design Method For Ultra-High Resolution Linear CCD Imagers

NASA Astrophysics Data System (ADS)

Sheu, Larry S.; Truong, Thanh; Yuzuki, Larry; Elhatem, Abdul; Kadekodi, Narayan

1984-11-01

This paper presents the design method to achieve ultra-high resolution linear imagers. This method utilizes advanced design rules and novel staggered bilinear photo sensor arrays with quadrilinear shift registers. Design constraint in the detector arrays and shift registers are analyzed. Imager architecture to achieve ultra-high resolution is presented. The characteristics of MTF, aliasing, speed, transfer efficiency and fine photolithography requirements associated with this architecture are also discussed. A CCD imager with advanced 1.5 um minimum feature size was fabricated. It is intended as a test vehicle for the next generation small sampling pitch ultra-high resolution CCD imager. Standard double-poly, two-phase shift registers were fabricated at an 8 um pitch using the advanced design rules. A special process step that blocked the source-drain implant from the shift register area was invented. This guaranteed excellent performance of the shift registers regardless of the small poly overlaps. A charge transfer efficiency of better than 0.99995 and maximum transfer speed of 8 MHz were achieved. The imager showed excellent performance. The dark current was less than 0.2 mV/ms, saturation 250 mV, adjacent photoresponse non-uniformity ± 4% and responsivity 0.7 V/ μJ/cm2 for the 8 μm x 6 μm photosensor size. The MTF was 0.6 at 62.5 cycles/mm. These results confirm the feasibility of the next generation ultra-high resolution CCD imagers.

Development of CCD imaging sensors for space applications, phase 1

NASA Technical Reports Server (NTRS)

Antcliffe, G. A.

1975-01-01

The results of an experimental investigation to develop a large area charge coupled device (CCD) imager for space photography applications are described. Details of the design and processing required to achieve 400 X 400 imagers are presented together with a discussion of the optical characterization techniques developed for this program. A discussion of several aspects of large CCD performance is given with detailed test reports. The areas covered include dark current, uniformity of optical response, square wave amplitude response, spectral responsivity and dynamic range.

3D morphology reconstruction using linear array CCD binocular stereo vision imaging system

NASA Astrophysics Data System (ADS)

Pan, Yu; Wang, Jinjiang

2018-01-01

Binocular vision imaging system, which has a small field of view, cannot reconstruct the 3-D shape of the dynamic object. We found a linear array CCD binocular vision imaging system, which uses different calibration and reconstruct methods. On the basis of the binocular vision imaging system, the linear array CCD binocular vision imaging systems which has a wider field of view can reconstruct the 3-D morphology of objects in continuous motion, and the results are accurate. This research mainly introduces the composition and principle of linear array CCD binocular vision imaging system, including the calibration, capture, matching and reconstruction of the imaging system. The system consists of two linear array cameras which were placed in special arrangements and a horizontal moving platform that can pick up objects. The internal and external parameters of the camera are obtained by calibrating in advance. And then using the camera to capture images of moving objects, the results are then matched and 3-D reconstructed. The linear array CCD binocular vision imaging systems can accurately measure the 3-D appearance of moving objects, this essay is of great significance to measure the 3-D morphology of moving objects.

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 quality evaluation method of pixel coupled electro-optical imaging system

NASA Astrophysics Data System (ADS)

He, Xu; Yuan, Li; Jin, Chunqi; Zhang, Xiaohui

2017-09-01

With advancements in high-resolution imaging optical fiber bundle fabrication technology, traditional photoelectric imaging system have become ;flexible; with greatly reduced volume and weight. However, traditional image quality evaluation models are limited by the coupling discrete sampling effect of fiber-optic image bundles and charge-coupled device (CCD) pixels. This limitation substantially complicates the design, optimization, assembly, and evaluation image quality of the coupled discrete sampling imaging system. Based on the transfer process of grayscale cosine distribution optical signal in the fiber-optic image bundle and CCD, a mathematical model of coupled modulation transfer function (coupled-MTF) is established. This model can be used as a basis for following studies on the convergence and periodically oscillating characteristics of the function. We also propose the concept of the average coupled-MTF, which is consistent with the definition of traditional MTF. Based on this concept, the relationships among core distance, core layer radius, and average coupled-MTF are investigated.

Fundamental performance differences of CMOS and CCD imagers: part V

NASA Astrophysics Data System (ADS)

Janesick, James R.; Elliott, Tom; Andrews, James; Tower, John; Pinter, Jeff

2013-02-01

Previous papers delivered over the last decade have documented developmental progress made on large pixel scientific CMOS imagers that match or surpass CCD performance. New data and discussions presented in this paper include: 1) a new buried channel CCD fabricated on a CMOS process line, 2) new data products generated by high performance custom scientific CMOS 4T/5T/6T PPD pixel imagers, 3) ultimate CTE and speed limits for large pixel CMOS imagers, 4) fabrication and test results of a flight 4k x 4k CMOS imager for NRL's SoloHi Solar Orbiter Mission, 5) a progress report on ultra large stitched Mk x Nk CMOS imager, 6) data generated by on-chip sub-electron CDS signal chain circuitry used in our imagers, 7) CMOS and CMOSCCD proton and electron radiation damage data for dose levels up to 10 Mrd, 8) discussions and data for a new class of PMOS pixel CMOS imagers and 9) future CMOS development work planned.

Driving techniques for high frame rate CCD camera

NASA Astrophysics Data System (ADS)

Guo, Weiqiang; Jin, Longxu; Xiong, Jingwu

2008-03-01

This paper describes a high-frame rate CCD camera capable of operating at 100 frames/s. This camera utilizes Kodak KAI-0340, an interline transfer CCD with 640(vertical)×480(horizontal) pixels. Two output ports are used to read out CCD data and pixel rates approaching 30 MHz. Because of its reduced effective opacity of vertical charge transfer registers, interline transfer CCD can cause undesired image artifacts, such as random white spots and smear generated in the registers. To increase frame rate, a kind of speed-up structure has been incorporated inside KAI-0340, then it is vulnerable to a vertical stripe effect. The phenomena which mentioned above may severely impair the image quality. To solve these problems, some electronic methods of eliminating these artifacts are adopted. Special clocking mode can dump the unwanted charge quickly, then the fast readout of the images, cleared of smear, follows immediately. Amplifier is used to sense and correct delay mismatch between the dual phase vertical clock pulses, the transition edges become close to coincident, so vertical stripes disappear. Results obtained with the CCD camera are shown.

Scientific CCD technology at JPL

NASA Technical Reports Server (NTRS)

Janesick, J.; Collins, S. A.; Fossum, E. R.

1991-01-01

Charge-coupled devices (CCD's) were recognized for their potential as an imaging technology almost immediately following their conception in 1970. Twenty years later, they are firmly established as the technology of choice for visible imaging. While consumer applications of CCD's, especially the emerging home video camera market, dominated manufacturing activity, the scientific market for CCD imagers has become significant. Activity of the Jet Propulsion Laboratory and its industrial partners in the area of CCD imagers for space scientific instruments is described. Requirements for scientific imagers are significantly different from those needed for home video cameras, and are described. An imager for an instrument on the CRAF/Cassini mission is described in detail to highlight achieved levels of performance.

A configurable distributed high-performance computing framework for satellite's TDI-CCD imaging simulation

NASA Astrophysics Data System (ADS)

Xue, Bo; Mao, Bingjing; Chen, Xiaomei; Ni, Guoqiang

2010-11-01

This paper renders a configurable distributed high performance computing(HPC) framework for TDI-CCD imaging simulation. It uses strategy pattern to adapt multi-algorithms. Thus, this framework help to decrease the simulation time with low expense. Imaging simulation for TDI-CCD mounted on satellite contains four processes: 1) atmosphere leads degradation, 2) optical system leads degradation, 3) electronic system of TDI-CCD leads degradation and re-sampling process, 4) data integration. Process 1) to 3) utilize diversity data-intensity algorithms such as FFT, convolution and LaGrange Interpol etc., which requires powerful CPU. Even uses Intel Xeon X5550 processor, regular series process method takes more than 30 hours for a simulation whose result image size is 1500 * 1462. With literature study, there isn't any mature distributing HPC framework in this field. Here we developed a distribute computing framework for TDI-CCD imaging simulation, which is based on WCF[1], uses Client/Server (C/S) layer and invokes the free CPU resources in LAN. The server pushes the process 1) to 3) tasks to those free computing capacity. Ultimately we rendered the HPC in low cost. In the computing experiment with 4 symmetric nodes and 1 server , this framework reduced about 74% simulation time. Adding more asymmetric nodes to the computing network, the time decreased namely. In conclusion, this framework could provide unlimited computation capacity in condition that the network and task management server are affordable. And this is the brand new HPC solution for TDI-CCD imaging simulation and similar applications.

Development of a CCD based solar speckle imaging system

NASA Astrophysics Data System (ADS)

Nisenson, Peter; Stachnik, Robert V.; Noyes, Robert W.

1986-02-01

A program to develop software and hardware for the purpose of obtaining high angular resolution images of the solar surface is described. The program included the procurement of a Charge Coupled Devices imaging system; an extensive laboratory and remote site testing of the camera system; the development of a software package for speckle image reconstruction which was eventually installed and tested at the Sacramento Peak Observatory; and experiments of the CCD system (coupled to an image intensifier) for low light level, narrow spectral band solar imaging.

Astrometrica: Astrometric data reduction of CCD images

NASA Astrophysics Data System (ADS)

Raab, Herbert

2012-03-01

Astrometrica is an interactive software tool for scientific grade astrometric data reduction of CCD images. The current version of the software is for the Windows 32bit operating system family. Astrometrica reads FITS (8, 16 and 32 bit integer files) and SBIG image files. The size of the images is limited only by available memory. It also offers automatic image calibration (Dark Frame and Flat Field correction), automatic reference star identification, automatic moving object detection and identification, and access to new-generation star catalogs (PPMXL, UCAC 3 and CMC-14), in addition to online help and other features. Astrometrica is shareware, available for use for a limited period of time (100 days) for free; special arrangements can be made for educational projects.

Failure Analysis of CCD Image Sensors Using SQUID and GMR Magnetic Current Imaging

NASA Technical Reports Server (NTRS)

Felt, Frederick S.

2005-01-01

During electrical testing of a Full Field CCD Image Senor, electrical shorts were detected on three of six devices. These failures occurred after the parts were soldered to the PCB. Failure analysis was performed to determine the cause and locations of these failures on the devices. After removing the fiber optic faceplate, optical inspection was performed on the CCDs to understand the design and package layout. Optical inspection revealed that the device had a light shield ringing the CCD array. This structure complicated the failure analysis. Alternate methods of analysis were considered, including liquid crystal, light and thermal emission, LT/A, TT/A SQUID, and MP. Of these, SQUID and MP techniques were pursued for further analysis. Also magnetoresistive current imaging technology is discussed and compared to SQUID.

CTK: A new CCD Camera at the University Observatory Jena

NASA Astrophysics Data System (ADS)

Mugrauer, M.

2009-05-01

The Cassegrain-Teleskop-Kamera (CTK) is a new CCD imager which is operated at the University Observatory Jena since begin of 2006. This article describes the main characteristics of the new camera. The properties of the CCD detector, the CTK image quality, as well as its detection limits for all filters are presented. Based on observations obtained with telescopes of the University Observatory Jena, which is operated by the Astrophysical Institute of the Friedrich-Schiller-University.

Method for implementation of back-illuminated CMOS or CCD imagers

NASA Technical Reports Server (NTRS)

Pain, Bedabrata (Inventor)

2008-01-01

A method for implementation of back-illuminated CMOS or CCD imagers. An oxide layer buried between silicon wafer and device silicon is provided. The oxide layer forms a passivation layer in the imaging structure. A device layer and interlayer dielectric are formed, and the silicon wafer is removed to expose the oxide layer.

Flat-panel detector, CCD cameras, and electron-beam-tube-based video for use in portal imaging

NASA Astrophysics Data System (ADS)

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

1998-07-01

This paper provides a comparison of some imaging parameters of four portal imaging systems at 6 MV: a flat panel detector, two CCD cameras and an electron beam tube based video camera. Measurements were made of signal and noise and consequently of signal-to-noise per pixel as a function of the exposure. All systems have a linear response with respect to exposure, and with the exception of the electron beam tube based video camera, 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 with both CCD-Cameras or with the electron beam tube based video camera. This is expected because most portal imaging systems using optical coupling with a lens exhibit severe quantum-sinks. The measurements of signal-and noise were complemented by images of a Las Vegas-type aluminum contrast detail phantom, located at the ISO-Center. These images were generated at an exposure of 1 MU. The flat-panel detector permits detection of Aluminum holes of 1.2 mm diameter and 1.6 mm depth, indicating the best signal-to-noise ratio. The CCD-cameras rank second and third in signal-to- noise ratio, permitting detection of Aluminum-holes of 1.2 mm diameter and 2.2 mm depth (CCD_1) and of 1.2 mm diameter and 3.2 mm depth (CCD_2) respectively, while the electron beam tube based video camera permits detection of only a hole of 1.2 mm diameter and 4.6 mm depth. Rank Order Filtering was applied to the raw images from the CCD-based systems 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 paper also presents data on the metal-phosphor's photon gain (the number of light-photons per interacting x-ray photon).

A programmable CCD driver circuit for multiphase CCD operation

NASA Technical Reports Server (NTRS)

Ewin, Audrey J.; Reed, Kenneth V.

1989-01-01

A programmable CCD (charge-coupled device) driver circuit was designed to drive CCDs in multiphased modes. The purpose of the drive electronics is to operate developmental CCD imaging arrays for NASA's tiltable moderate resolution imaging spectrometer (MODIS-T). Five objectives for the driver were considered during its design: (1) the circuit drives CCD electrode voltages between 0 V and +30 V to produce reasonable potential wells, (2) the driving sequence is started with one input signal, (3) the driving sequence is started with one input signal, (4) the circuit allows programming of frame sequences required by arrays of any size, (5) it produces interfacing signals for the CCD and the DTF (detector test facility). Simulation of the driver verified its function with the master clock running up to 10 MHz. This suggests a maximum rate of 400,000 pixels/s. Timing and packaging parameters were verified. The design uses 54 TTL (transistor-transistor logic) chips. Two versions of hardware were fabricated: wirewrap and printed circuit board. Both were verified functionally with a logic analyzer.

Development of proton CT imaging system using plastic scintillator and CCD camera

NASA Astrophysics Data System (ADS)

Tanaka, Sodai; Nishio, Teiji; Matsushita, Keiichiro; Tsuneda, Masato; Kabuki, Shigeto; Uesaka, Mitsuru

2016-06-01

A proton computed tomography (pCT) imaging system was constructed for evaluation of the error of an x-ray CT (xCT)-to-WEL (water-equivalent length) conversion in treatment planning for proton therapy. In this system, the scintillation light integrated along the beam direction is obtained by photography using the CCD camera, which enables fast and easy data acquisition. The light intensity is converted to the range of the proton beam using a light-to-range conversion table made beforehand, and a pCT image is reconstructed. An experiment for demonstration of the pCT system was performed using a 70 MeV proton beam provided by the AVF930 cyclotron at the National Institute of Radiological Sciences. Three-dimensional pCT images were reconstructed from the experimental data. A thin structure of approximately 1 mm was clearly observed, with spatial resolution of pCT images at the same level as that of xCT images. The pCT images of various substances were reconstructed to evaluate the pixel value of pCT images. The image quality was investigated with regard to deterioration including multiple Coulomb scattering.

Phase shifting white light interferometry using colour CCD for optical metrology and bio-imaging applications

NASA Astrophysics Data System (ADS)

Upputuri, Paul Kumar; Pramanik, Manojit

2018-02-01

Phase shifting white light interferometry (PSWLI) has been widely used for optical metrology applications because of their precision, reliability, and versatility. White light interferometry using monochrome CCD makes the measurement process slow for metrology applications. WLI integrated with Red-Green-Blue (RGB) CCD camera is finding imaging applications in the fields optical metrology and bio-imaging. Wavelength dependent refractive index profiles of biological samples were computed from colour white light interferograms. In recent years, whole-filed refractive index profiles of red blood cells (RBCs), onion skin, fish cornea, etc. were measured from RGB interferograms. In this paper, we discuss the bio-imaging applications of colour CCD based white light interferometry. The approach makes the measurement faster, easier, cost-effective, and even dynamic by using single fringe analysis methods, for industrial applications.

Design and Fabrication of High-Efficiency CMOS/CCD Imagers

NASA Technical Reports Server (NTRS)

Pain, Bedabrata

2007-01-01

An architecture for back-illuminated complementary metal oxide/semiconductor (CMOS) and charge-coupled-device (CCD) ultraviolet/visible/near infrared- light image sensors, and a method of fabrication to implement the architecture, are undergoing development. The architecture and method are expected to enable realization of the full potential of back-illuminated CMOS/CCD imagers to perform with high efficiency, high sensitivity, excellent angular response, and in-pixel signal processing. The architecture and method are compatible with next-generation CMOS dielectric-forming and metallization techniques, and the process flow of the method is compatible with process flows typical of the manufacture of very-large-scale integrated (VLSI) circuits. The architecture and method overcome all obstacles that have hitherto prevented high-yield, low-cost fabrication of back-illuminated CMOS/CCD imagers by use of standard VLSI fabrication tools and techniques. It is not possible to discuss the obstacles in detail within the space available for this article. Briefly, the obstacles are posed by the problems of generating light-absorbing layers having desired uniform and accurate thicknesses, passivation of surfaces, forming structures for efficient collection of charge carriers, and wafer-scale thinning (in contradistinction to diescale thinning). A basic element of the present architecture and method - the element that, more than any other, makes it possible to overcome the obstacles - is the use of an alternative starting material: Instead of starting with a conventional bulk-CMOS wafer that consists of a p-doped epitaxial silicon layer grown on a heavily-p-doped silicon substrate, one starts with a special silicon-on-insulator (SOI) wafer that consists of a thermal oxide buried between a lightly p- or n-doped, thick silicon layer and a device silicon layer of appropriate thickness and doping. The thick silicon layer is used as a handle: that is, as a mechanical support for the

Design of multi-mode compatible image acquisition system for HD area array CCD

NASA Astrophysics Data System (ADS)

Wang, Chen; Sui, Xiubao

2014-11-01

Combining with the current development trend in video surveillance-digitization and high-definition, a multimode-compatible image acquisition system for HD area array CCD is designed. The hardware and software designs of the color video capture system of HD area array CCD KAI-02150 presented by Truesense Imaging company are analyzed, and the structure parameters of the HD area array CCD and the color video gathering principle of the acquisition system are introduced. Then, the CCD control sequence and the timing logic of the whole capture system are realized. The noises of the video signal (KTC noise and 1/f noise) are filtered by using the Correlated Double Sampling (CDS) technique to enhance the signal-to-noise ratio of the system. The compatible designs in both software and hardware for the two other image sensors of the same series: KAI-04050 and KAI-08050 are put forward; the effective pixels of these two HD image sensors are respectively as many as four million and eight million. A Field Programmable Gate Array (FPGA) is adopted as the key controller of the system to perform the modularization design from top to bottom, which realizes the hardware design by software and improves development efficiency. At last, the required time sequence driving is simulated accurately by the use of development platform of Quartus II 12.1 combining with VHDL. The result of the simulation indicates that the driving circuit is characterized by simple framework, low power consumption, and strong anti-interference ability, which meet the demand of miniaturization and high-definition for the current tendency.

Matching CCD images to a stellar catalog using locality-sensitive hashing

NASA Astrophysics Data System (ADS)

Liu, Bo; Yu, Jia-Zong; Peng, Qing-Yu

2018-02-01

The usage of a subset of observed stars in a CCD image to find their corresponding matched stars in a stellar catalog is an important issue in astronomical research. Subgraph isomorphic-based algorithms are the most widely used methods in star catalog matching. When more subgraph features are provided, the CCD images are recognized better. However, when the navigation feature database is large, the method requires more time to match the observing model. To solve this problem, this study investigates further and improves subgraph isomorphic matching algorithms. We present an algorithm based on a locality-sensitive hashing technique, which allocates quadrilateral models in the navigation feature database into different hash buckets and reduces the search range to the bucket in which the observed quadrilateral model is located. Experimental results indicate the effectivity of our method.

Method for eliminating artifacts in CCD imagers

DOEpatents

Turko, B.T.; Yates, G.J.

1992-06-09

An electronic method for eliminating artifacts in a video camera employing a charge coupled device (CCD) as an image sensor is disclosed. The method comprises the step of initializing the camera prior to normal read out and includes a first dump cycle period for transferring radiation generated charge into the horizontal register while the decaying image on the phosphor being imaged is being integrated in the photosites, and a second dump cycle period, occurring after the phosphor image has decayed, for rapidly dumping unwanted smear charge which has been generated in the vertical registers. Image charge is then transferred from the photosites and to the vertical registers and read out in conventional fashion. The inventive method allows the video camera to be used in environments having high ionizing radiation content, and to capture images of events of very short duration and occurring either within or outside the normal visual wavelength spectrum. Resultant images are free from ghost, smear and smear phenomena caused by insufficient opacity of the registers and, and are also free from random damage caused by ionization charges which exceed the charge limit capacity of the photosites. 3 figs.

Recent CCD Images of Hubble's Variable Nebula (NGC 2261)

NASA Astrophysics Data System (ADS)

Meisel, D.; Dykstra, W.; Schulitz, F.

1992-05-01

Four CCD exposures of Hubble's Variable Nebula were taken with the RIT Kodak KF-4200 array using the 0.6m Hawaii telescope at Mauna Kea. The field of view was 5' x 7' of arc with a resolution of 0.3" per pixel. The effective wavelengths were v 5300A, r 6200A, i 8000A and ii 9000A. Preliminary image processing has been done on Macintosh IIfxs and LCs using NIH Image1.44b20 and has revealed considerable detail in the dust cloud, but no obvious obscuration features as seen at past epochs. Final image processing is continuing on Sun workstations using IRAF and SAO Image. Differences of structure between the wavelength bands and comparisons between images at other epochs, CO maps, and polarimetry will be discussed.

High-speed high-resolution epifluorescence imaging system using CCD sensor and digital storage for neurobiological research

NASA Astrophysics Data System (ADS)

Takashima, Ichiro; Kajiwara, Riichi; Murano, Kiyo; Iijima, Toshio; Morinaka, Yasuhiro; Komobuchi, Hiroyoshi

2001-04-01

We have designed and built a high-speed CCD imaging system for monitoring neural activity in an exposed animal cortex stained with a voltage-sensitive dye. Two types of custom-made CCD sensors were developed for this system. The type I chip has a resolution of 2664 (H) X 1200 (V) pixels and a wide imaging area of 28.1 X 13.8 mm, while the type II chip has 1776 X 1626 pixels and an active imaging area of 20.4 X 18.7 mm. The CCD arrays were constructed with multiple output amplifiers in order to accelerate the readout rate. The two chips were divided into either 24 (I) or 16 (II) distinct areas that were driven in parallel. The parallel CCD outputs were digitized by 12-bit A/D converters and then stored in the frame memory. The frame memory was constructed with synchronous DRAM modules, which provided a capacity of 128 MB per channel. On-chip and on-memory binning methods were incorporated into the system, e.g., this enabled us to capture 444 X 200 pixel-images for periods of 36 seconds at a rate of 500 frames/second. This system was successfully used to visualize neural activity in the cortices of rats, guinea pigs, and monkeys.

Test technology on divergence angle of laser range finder based on CCD imaging fusion

NASA Astrophysics Data System (ADS)

Shi, Sheng-bing; Chen, Zhen-xing; Lv, Yao

2016-09-01

Laser range finder has been equipped with all kinds of weapons, such as tank, ship, plane and so on, is important component of fire control system. Divergence angle is important performance and incarnation of horizontal resolving power for laser range finder, is necessary appraised test item in appraisal test. In this paper, based on high accuracy test on divergence angle of laser range finder, divergence angle test system is designed based on CCD imaging, divergence angle of laser range finder is acquired through fusion technology for different attenuation imaging, problem that CCD characteristic influences divergence angle test is solved.

Method for eliminating artifacts in CCD imagers

DOEpatents

Turko, Bojan T.; Yates, George J.

1992-01-01

An electronic method for eliminating artifacts in a video camera (10) employing a charge coupled device (CCD) (12) as an image sensor. The method comprises the step of initializing the camera (10) prior to normal read out and includes a first dump cycle period (76) for transferring radiation generated charge into the horizontal register (28) while the decaying image on the phosphor (39) being imaged is being integrated in the photosites, and a second dump cycle period (78), occurring after the phosphor (39) image has decayed, for rapidly dumping unwanted smear charge which has been generated in the vertical registers (32). Image charge is then transferred from the photosites (36) and (38) to the vertical registers (32) and read out in conventional fashion. The inventive method allows the video camera (10) to be used in environments having high ionizing radiation content, and to capture images of events of very short duration and occurring either within or outside the normal visual wavelength spectrum. Resultant images are free from ghost, smear and smear phenomena caused by insufficient opacity of the registers (28) and (32), and are also free from random damage caused by ionization charges which exceed the charge limit capacity of the photosites (36) and (37).

Structure for implementation of back-illuminated CMOS or CCD imagers

NASA Technical Reports Server (NTRS)

Pain, Bedabrata (Inventor); Cunningham, Thomas J. (Inventor)

2009-01-01

A structure for implementation of back-illuminated CMOS or CCD imagers. An epitaxial silicon layer is connected with a passivation layer, acting as a junction anode. The epitaxial silicon layer converts light passing through the passivation layer and collected by the imaging structure to photoelectrons. A semiconductor well is also provided, located opposite the passivation layer with respect to the epitaxial silicon layer, acting as a junction cathode. Prior to detection, light does not pass through a dielectric separating interconnection metal layers.

Development and use of an L3CCD high-cadence imaging system for Optical Astronomy

NASA Astrophysics Data System (ADS)

Sheehan, Brendan J.; Butler, Raymond F.

2008-02-01

A high cadence imaging system, based on a Low Light Level CCD (L3CCD) camera, has been developed for photometric and polarimetric applications. The camera system is an iXon DV-887 from Andor Technology, which uses a CCD97 L3CCD detector from E2V technologies. This is a back illuminated device, giving it an extended blue response, and has an active area of 512×512 pixels. The camera system allows frame-rates ranging from 30 fps (full frame) to 425 fps (windowed & binned frame). We outline the system design, concentrating on the calibration and control of the L3CCD camera. The L3CCD detector can be either triggered directly by a GPS timeserver/frequency generator or be internally triggered. A central PC remotely controls the camera computer system and timeserver. The data is saved as standard `FITS' files. The large data loads associated with high frame rates, leads to issues with gathering and storing the data effectively. To overcome such problems, a specific data management approach is used, and a Python/PYRAF data reduction pipeline was written for the Linux environment. This uses calibration data collected either on-site, or from lab based measurements, and enables a fast and reliable method for reducing images. To date, the system has been used twice on the 1.5 m Cassini Telescope in Loiano (Italy) we present the reduction methods and observations made.

Quasi-Speckle Measurements of Close Double Stars With a CCD Camera

NASA Astrophysics Data System (ADS)

Harshaw, Richard

2017-01-01

CCD measurements of visual double stars have been an active area of amateur observing for several years now. However, most CCD measurements rely on “lucky imaging” (selecting a very small percentage of the best frames of a larger frame set so as to get the best “frozen” atmosphere for the image), a technique that has limitations with regards to how close the stars can be and still be cleanly resolved in the lucky image. In this paper, the author reports how using deconvolution stars in the analysis of close double stars can greatly enhance the quality of the autocorellogram, leading to a more precise solution using speckle reduction software rather than lucky imaging.

A New Serial-direction Trail Effect in CCD Images of the Lunar-based Ultraviolet Telescope

NASA Astrophysics Data System (ADS)

Wu, C.; Deng, J. S.; Guyonnet, A.; Antilogus, P.; Cao, L.; Cai, H. B.; Meng, X. M.; Han, X. H.; Qiu, Y. L.; Wang, J.; Wang, S.; Wei, J. Y.; Xin, L. P.; Li, G. W.

2016-10-01

Unexpected trails have been seen subsequent to relative bright sources in astronomical images taken with the CCD camera of the Lunar-based Ultraviolet Telescope (LUT) since its first light on the Moon’s surface. The trails can only be found in the serial-direction of CCD readout, differing themselves from image trails of radiation-damaged space-borne CCDs, which usually appear in the parallel-readout direction. After analyzing the same trail defects following warm pixels (WPs) in dark frames, we found that the relative intensity profile of the LUT CCD trails can be expressed as an exponential function of the distance i (in number of pixels) of the trailing pixel to the original source (or WP), i.e., {\\mathtt{\\exp }}(α {\\mathtt{i}}+β ). The parameters α and β seem to be independent of the CCD temperature, intensity of the source (or WP), and its position in the CCD frame. The main trail characteristics show evolution occurring at an increase rate of ˜(7.3 ± 3.6) × 10-4 in the first two operation years. The trails affect the consistency of the profiles of different brightness sources, which make smaller aperture photometry have larger extra systematic error. The astrometric uncertainty caused by the trails is too small to be acceptable based on LUT requirements for astrometry accuracy. Based on the empirical profile model, a correction method has been developed for LUT images that works well for restoring the fluxes of astronomical sources that are lost in trailing pixels.

CTK-II & RTK: The CCD-cameras operated at the auxiliary telescopes of the University Observatory Jena

NASA Astrophysics Data System (ADS)

Mugrauer, M.

2016-03-01

The Cassegrain-Teleskop-Kamera (CTK-II) and the Refraktor-Teleskop-Kamera (RTK) are two CCD-imagers which are operated at the 25 cm Cassegrain and 20 cm refractor auxiliary telescopes of the University Observatory Jena. This article describes the main characteristics of these instruments. The properties of the CCD-detectors, the astrometry, the image quality, and the detection limits of both CCD-cameras, as well as some results of ongoing observing projects, carried out with these instruments, are presented. Based on observations obtained with telescopes of the University Observatory Jena, which is operated by the Astrophysical Institute of the Friedrich-Schiller-University.

The Speckle Toolbox: A Powerful Data Reduction Tool for CCD Astrometry

NASA Astrophysics Data System (ADS)

Harshaw, Richard; Rowe, David; Genet, Russell

2017-01-01

Recent advances in high-speed low-noise CCD and CMOS cameras, coupled with breakthroughs in data reduction software that runs on desktop PCs, has opened the domain of speckle interferometry and high-accuracy CCD measurements of double stars to amateurs, allowing them to do useful science of high quality. This paper describes how to use a speckle interferometry reduction program, the Speckle Tool Box (STB), to achieve this level of result. For over a year the author (Harshaw) has been using STB (and its predecessor, Plate Solve 3) to obtain measurements of double stars based on CCD camera technology for pairs that are either too wide (the stars not sharing the same isoplanatic patch, roughly 5 arc-seconds in diameter) or too faint to image in the coherence time required for speckle (usually under 40ms). This same approach - using speckle reduction software to measure CCD pairs with greater accuracy than possible with lucky imaging - has been used, it turns out, for several years by the U. S. Naval Observatory.

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.

SU-C-207A-03: Development of Proton CT Imaging System Using Thick Scintillator and CCD Camera

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

Tanaka, S; Uesaka, M; Nishio, T

2016-06-15

Purpose: In the treatment planning of proton therapy, Water Equivalent Length (WEL), which is the parameter for the calculation of dose and the range of proton, is derived by X-ray CT (xCT) image and xCT-WEL conversion. However, about a few percent error in the accuracy of proton range calculation through this conversion has been reported. The purpose of this study is to construct a proton CT (pCT) imaging system for an evaluation of the error. Methods: The pCT imaging system was constructed with a thick scintillator and a cooled CCD camera, which acquires the two-dimensional image of integrated value ofmore » the scintillation light toward the beam direction. The pCT image is reconstructed by FBP method using a correction between the light intensity and residual range of proton beam. An experiment for the demonstration of this system was performed with 70-MeV proton beam provided by NIRS cyclotron. The pCT image of several objects reconstructed from the experimental data was evaluated quantitatively. Results: Three-dimensional pCT images of several objects were reconstructed experimentally. A finestructure of approximately 1 mm was clearly observed. The position resolution of pCT image was almost the same as that of xCT image. And the error of proton CT pixel value was up to 4%. The deterioration of image quality was caused mainly by the effect of multiple Coulomb scattering. Conclusion: We designed and constructed the pCT imaging system using a thick scintillator and a CCD camera. And the system was evaluated with the experiment by use of 70-MeV proton beam. Three-dimensional pCT images of several objects were acquired by the system. This work was supported by JST SENTAN Grant Number 13A1101 and JSPS KAKENHI Grant Number 15H04912.« less

Quadrilinear CCD sensors for the multispectral channel of spaceborne imagers

NASA Astrophysics Data System (ADS)

Materne, Alex; Gili, Bruno; Laubier, David; Gimenez, Thierry

2001-12-01

The PLEIADES-HR Earth Observation satellites will combine a high resolution panchromatic channel -- 0.7 m at nadir -- and a multispectral channel allowing a 2.8 m resolution. This paper presents the main specifications, design and performances of a 52 microns pitch quadrilinear CCD sensor developed by ATMEL under CNES contract, for the multispectral channel of the PLEIADES-HR instrument. The monolithic CCD device includes four lines of 1500 pixels, each line dedicated to a narrow spectral band within blue to near infra red spectrum. The design of the photodiodes and CCD registers, with larger size than those developed up to now for CNES spaceborne imagers, needed some specific structures to break the large equipotential areas where charge do not flow properly. Results are presented on the options which were experimented to improve sensitivity, maintain transfer efficiency and reduce power dissipation. The four spectral bands are achieved by four stripe filters made by SAGEM-REOSC PRODUCTS on a glass substrate, to be assembled on the sensor window. Line to line spacing on the silicon die takes into account the results of straylight analysis. A mineral layer, with high optical absorption performances is deposited between photosensitive lines to further reduce straylight.

The future scientific CCD

NASA Technical Reports Server (NTRS)

Janesick, J. R.; Elliott, T.; Collins, S.; Marsh, H.; Blouke, M. M.

1984-01-01

Since the first introduction of charge-coupled devices (CCDs) in 1970, CCDs have been considered for applications related to memories, logic circuits, and the detection of visible radiation. It is pointed out, however, that the mass market orientation of CCD development has left largely untapped the enormous potential of these devices for advanced scientific instrumentation. The present paper has, therefore, the objective to introduce the CCD characteristics to the scientific community, taking into account prospects for further improvement. Attention is given to evaluation criteria, a summary of current CCDs, CCD performance characteristics, absolute calibration tools, quantum efficiency, aspects of charge collection, charge transfer efficiency, read noise, and predictions regarding the characteristics of the next generation of silicon scientific CCD imagers.

Development of a CCD array as an imaging detector for advanced X-ray astrophysics facilities

NASA Technical Reports Server (NTRS)

Schwartz, D. A.

1981-01-01

The development of a charge coupled device (CCD) X-ray imager for a large aperture, high angular resolution X-ray telescope is discussed. Existing CCDs were surveyed and three candidate concepts were identified. An electronic camera control and computer interface, including software to drive a Fairchild 211 CCD, is described. In addition a vacuum mounting and cooling system is discussed. Performance data for the various components are given.

Smear correction of highly variable, frame-transfer CCD images with application to polarimetry.

PubMed

Iglesias, Francisco A; Feller, Alex; Nagaraju, Krishnappa

2015-07-01

Image smear, produced by the shutterless operation of frame-transfer CCD detectors, can be detrimental for many imaging applications. Existing algorithms used to numerically remove smear do not contemplate cases where intensity levels change considerably between consecutive frame exposures. In this report, we reformulate the smearing model to include specific variations of the sensor illumination. The corresponding desmearing expression and its noise properties are also presented and demonstrated in the context of fast imaging polarimetry.

CCD research. [design, fabrication, and applications

NASA Technical Reports Server (NTRS)

Gassaway, J. D.

1976-01-01

The fundamental problems encountered in designing, fabricating, and applying CCD's are reviewed. Investigations are described and results and conclusions are given for the following: (1) the development of design analyses employing computer aided techniques and their application to the design of a grapped structure; (2) the role of CCD's in applications to electronic functions, in particular, signal processing; (3) extending the CCD to silicon films on sapphire (SOS); and (4) all aluminum transfer structure with low noise input-output circuits. Related work on CCD imaging devices is summarized.

Delta-doped CCD's as low-energy particle detectors and imagers

NASA Technical Reports Server (NTRS)

Nikzad, Shouleh (Inventor); Hoenk, Michael E. (Inventor); Hecht, Michael H. (Inventor)

2002-01-01

The back surface of a thinned charged-coupled device (CCD) is treated to eliminate the backside potential well that appears in a conventional thinned CCD during backside illumination. The backside of the CCD includes a delta layer of high-concentration dopant confined to less than one monolayer of the crystal semiconductor. The thinned, delta-doped CCD is used to detect very low-energy particles that penetrate less than 1.0 nm into the CCD, including electrons having energies less than 1000 eV and protons having energies less than 10 keV.

Astrometric Quality of the USNO CCD Astrograph (UCA)

NASA Astrophysics Data System (ADS)

Zacharias, N.

1997-05-01

The USNO 8-inch astrograph has been equipped with a Kodak 1536x1024 pixel CCD since June 1995, operating in a 570-650 nm bandpass. With 3-minute exposures well exposed images are obtained in the magnitude range R ~ 8.5 - 13.5(m) . An astrometric precision of 10 to 15 mas for those stars is estimated from frame-to-frame comparisons. External comparisons reveal an accuracy of about 15 mas for those stars in a 20' field of view. For fainter stars, the error budget is dominated by the S/N ratio, reaching ~ 100 mas at R=16(m) under good observing conditions.

Adjustment of multi-CCD-chip-color-camera heads

NASA Astrophysics Data System (ADS)

Guyenot, Volker; Tittelbach, Guenther; Palme, Martin

1999-09-01

The principle of beam-splitter-multi-chip cameras consists in splitting an image into differential multiple images of different spectral ranges and in distributing these onto separate black and white CCD-sensors. The resulting electrical signals from the chips are recombined to produce a high quality color picture on the monitor. Because this principle guarantees higher resolution and sensitivity in comparison to conventional single-chip camera heads, the greater effort is acceptable. Furthermore, multi-chip cameras obtain the compete spectral information for each individual object point while single-chip system must rely on interpolation. In a joint project, Fraunhofer IOF and STRACON GmbH and in future COBRA electronic GmbH develop methods for designing the optics and dichroitic mirror system of such prism color beam splitter devices. Additionally, techniques and equipment for the alignment and assembly of color beam splitter-multi-CCD-devices on the basis of gluing with UV-curable adhesives have been developed, too.

UV-sensitive scientific CCD image sensors

NASA Astrophysics Data System (ADS)

Vishnevsky, Grigory I.; Kossov, Vladimir G.; Iblyaminova, A. F.; Lazovsky, Leonid Y.; Vydrevitch, Michail G.

1997-06-01

An investigation of probe laser irradiation interaction with substances containing in an environment has long since become a recognized technique for contamination detection and identification. For this purpose, a near and midrange-IR laser irradiation is traditionally used. However, as many works presented on last ecology monitoring conferences show, in addition to traditional systems, rapidly growing are systems with laser irradiation from near-UV range (250 - 500 nm). Use of CCD imagers is one of the prerequisites for this allowing the development of a multi-channel computer-based spectral research system. To identify and analyze contaminating impurities on an environment, such methods as laser fluorescence analysis, UV absorption and differential spectroscopy, Raman scattering are commonly used. These methods are used to identify a large number of impurities (petrol, toluene, Xylene isomers, SO2, acetone, methanol), to detect and identify food pathogens in real time, to measure a concentration of NH3, SO2 and NO in combustion outbursts, to detect oil products in a water, to analyze contaminations in ground waters, to define ozone distribution in the atmosphere profile, to monitor various chemical processes including radioactive materials manufacturing, heterogeneous catalytic reactions, polymers production etc. Multi-element image sensor with enhanced UV sensitivity, low optical non-uniformity, low intrinsic noise and high dynamic range is a key element of all above systems. Thus, so called Virtual Phase (VP) CCDs possessing all these features, seems promising for ecology monitoring spectral measuring systems. Presently, a family of VP CCDs with different architecture and number of pixels is developed and being manufactured. All CCDs from this family are supported with a precise slow-scan digital image acquisition system that can be used in various image processing systems in astronomy, biology, medicine, ecology etc. An image is displayed directly on a PC

Vacuum compatible miniature CCD camera head

DOEpatents

Conder, Alan D.

2000-01-01

A charge-coupled device (CCD) camera head which can replace film for digital imaging of visible light, ultraviolet radiation, and soft to penetrating x-rays, such as within a target chamber where laser produced plasmas are studied. The camera head is small, capable of operating both in and out of a vacuum environment, and is versatile. The CCD camera head uses PC boards with an internal heat sink connected to the chassis for heat dissipation, which allows for close(0.04" for example) stacking of the PC boards. Integration of this CCD camera head into existing instrumentation provides a substantial enhancement of diagnostic capabilities for studying high energy density plasmas, for a variety of military industrial, and medical imaging applications.

Transport and installation of the Dark Energy Survey CCD imager

NASA Astrophysics Data System (ADS)

Derylo, Greg; Chi, Edward; Diehl, H. Thomas; Estrada, Juan; Flaugher, Brenna; Schultz, Ken

2012-09-01

The Dark Energy Survey CCD imager was constructed at the Fermi National Accelerator Laboratory and delivered to the Cerro Tololo Inter-American Observatory in Chile for installation onto the Blanco 4m telescope. Several efforts are described relating to preparation of the instrument for transport, development and testing of a shipping crate designed to minimize transportation loads transmitted to the camera, and inspection of the imager upon arrival at the observatory. Transportation loads were monitored and are described. For installation of the imager at the telescope prime focus, where it mates with its previously-installed optical corrector, specialized tooling was developed to safely lift, support, and position the vessel. The installation and removal processes were tested on the Telescope Simulator mockup at FNAL, thus minimizing technical and schedule risk for the work performed at CTIO. Final installation of the imager is scheduled for August 2012.

Fully depleted back illuminated CCD

DOEpatents

Holland, Stephen Edward

2001-01-01

A backside illuminated charge coupled device (CCD) is formed of a relatively thick high resistivity photon sensitive silicon substrate, with frontside electronic circuitry, and an optically transparent backside ohmic contact for applying a backside voltage which is at least sufficient to substantially fully deplete the substrate. A greater bias voltage which overdepletes the substrate may also be applied. One way of applying the bias voltage to the substrate is by physically connecting the voltage source to the ohmic contact. An alternate way of applying the bias voltage to the substrate is to physically connect the voltage source to the frontside of the substrate, at a point outside the depletion region. Thus both frontside and backside contacts can be used for backside biasing to fully deplete the substrate. Also, high resistivity gaps around the CCD channels and electrically floating channel stop regions can be provided in the CCD array around the CCD channels. The CCD array forms an imaging sensor useful in astronomy.

CCD imaging system for the EUV solar telescope

NASA Astrophysics Data System (ADS)

Gong, Yan; Song, Qian; Ye, Bing-Xun

2006-01-01

In order to develop the detector adapted to the space solar telescope, we have built a CCD camera system capable of working in the extra ultraviolet (EUV) band, which is composed of one phosphor screen, one intensified system using a photocathode/micro-channel plate(MCP)/ phosphor, one optical taper and one chip of front-illuminated (FI) CCD without screen windows. All of them were stuck one by one with optical glue. The working principle of the camera system is presented; moreover we have employed the mesh experiment to calibrate and test the CCD camera system in 15~24nm, the position resolution of about 19 μm is obtained at the wavelength of 17.1nm and 19.5nm.

Fundamental performance differences between CMOS and CCD imagers, part IV

NASA Astrophysics Data System (ADS)

Janesick, James; Pinter, Jeff; Potter, Robert; Elliott, Tom; Andrews, James; Tower, John; Grygon, Mark; Keller, Dave

2010-07-01

This paper is a continuation of past papers written on fundamental performance differences of scientific CMOS and CCD imagers. New characterization results presented below include: 1). a new 1536 × 1536 × 8μm 5TPPD pixel CMOS imager, 2). buried channel MOSFETs for random telegraph noise (RTN) and threshold reduction, 3) sub-electron noise pixels, 4) 'MIM pixel' for pixel sensitivity (V/e-) control, 5) '5TPPD RING pixel' for large pixel, high-speed charge transfer applications, 6) pixel-to-pixel blooming control, 7) buried channel photo gate pixels and CMOSCCDs, 8) substrate bias for deep depletion CMOS imagers, 9) CMOS dark spikes and dark current issues and 10) high energy radiation damage test data. Discussions are also given to a 1024 × 1024 × 16 um 5TPPD pixel imager currently in fabrication and new stitched CMOS imagers that are in the design phase including 4k × 4k × 10 μm and 10k × 10k × 10 um imager formats.

Digital image measurement of specimen deformation based on CCD cameras and Image J software: an application to human pelvic biomechanics

NASA Astrophysics Data System (ADS)

Jia, Yongwei; Cheng, Liming; Yu, Guangrong; Lou, Yongjian; Yu, Yan; Chen, Bo; Ding, Zuquan

2008-03-01

A method of digital image measurement of specimen deformation based on CCD cameras and Image J software was developed. This method was used to measure the biomechanics behavior of human pelvis. Six cadaveric specimens from the third lumbar vertebra to the proximal 1/3 part of femur were tested. The specimens without any structural abnormalities were dissected of all soft tissue, sparing the hip joint capsules and the ligaments of the pelvic ring and floor. Markers with black dot on white background were affixed to the key regions of the pelvis. Axial loading from the proximal lumbar was applied by MTS in the gradient of 0N to 500N, which simulated the double feet standing stance. The anterior and lateral images of the specimen were obtained through two CCD cameras. Based on Image J software, digital image processing software, which can be freely downloaded from the National Institutes of Health, digital 8-bit images were processed. The procedure includes the recognition of digital marker, image invert, sub-pixel reconstruction, image segmentation, center of mass algorithm based on weighted average of pixel gray values. Vertical displacements of S1 (the first sacral vertebrae) in front view and micro-angular rotation of sacroiliac joint in lateral view were calculated according to the marker movement. The results of digital image measurement showed as following: marker image correlation before and after deformation was excellent. The average correlation coefficient was about 0.983. According to the 768 × 576 pixels image (pixel size 0.68mm × 0.68mm), the precision of the displacement detected in our experiment was about 0.018 pixels and the comparatively error could achieve 1.11\\perthou. The average vertical displacement of S1 of the pelvis was 0.8356+/-0.2830mm under vertical load of 500 Newtons and the average micro-angular rotation of sacroiliac joint in lateral view was 0.584+/-0.221°. The load-displacement curves obtained from our optical measure system

Performance of the STIS CCD Dark Rate Temperature Correction

NASA Astrophysics Data System (ADS)

Branton, Doug; STScI STIS Team

2018-06-01

Since July 2001, the Space Telescope Imaging Spectrograph (STIS) onboard Hubble has operated on its Side-2 electronics due to a failure in the primary Side-1 electronics. While nearly identical, Side-2 lacks a functioning temperature sensor for the CCD, introducing a variability in the CCD operating temperature. Previous analysis utilized the CCD housing temperature telemetry to characterize the relationship between the housing temperature and the dark rate. It was found that a first-order 7%/°C uniform dark correction demonstrated a considerable improvement in the quality of dark subtraction on Side-2 era CCD data, and that value has been used on all Side-2 CCD darks since. In this report, we show how this temperature correction has performed historically. We compare the current 7%/°C value against the ideal first-order correction at a given time (which can vary between ~6%/°C and ~10%/°C) as well as against a more complex second-order correction that applies a unique slope to each pixel as a function of dark rate and time. At worst, the current correction has performed ~1% worse than the second-order correction. Additionally, we present initial evidence suggesting that the variability in pixel temperature-sensitivity is significant enough to warrant a temperature correction that considers pixels individually rather than correcting them uniformly.

An abuttable CCD imager for visible and X-ray focal plane arrays

NASA Technical Reports Server (NTRS)

Burke, Barry E.; Mountain, Robert W.; Harrison, David C.; Bautz, Marshall W.; Doty, John P.

1991-01-01

A frame-transfer silicon charge-coupled-device (CCD) imager has been developed that can be closely abutted to other imagers on three sides of the imaging array. It is intended for use in multichip arrays. The device has 420 x 420 pixels in the imaging and frame-store regions and is constructed using a three-phase triple-polysilicon process. Particular emphasis has been placed on achieving low-noise charge detection for low-light-level imaging in the visible and maximum energy resolution for X-ray spectroscopic applications. Noise levels of 6 electrons at 1-MHz and less than 3 electrons at 100-kHz data rates have been achieved. Imagers have been fabricated on 1000-Ohm-cm material to maximize quantum efficiency and minimize split events in the soft X-ray regime.

MMW/THz imaging using upconversion to visible, based on glow discharge detector array and CCD camera

NASA Astrophysics Data System (ADS)

Aharon, Avihai; Rozban, Daniel; Abramovich, Amir; Yitzhaky, Yitzhak; Kopeika, Natan S.

2017-10-01

An inexpensive upconverting MMW/THz imaging method is suggested here. The method is based on glow discharge detector (GDD) and silicon photodiode or simple CCD/CMOS camera. The GDD was previously found to be an excellent room-temperature MMW radiation detector by measuring its electrical current. The GDD is very inexpensive and it is advantageous due to its wide dynamic range, broad spectral range, room temperature operation, immunity to high power radiation, and more. An upconversion method is demonstrated here, which is based on measuring the visual light emitting from the GDD rather than its electrical current. The experimental setup simulates a setup that composed of a GDD array, MMW source, and a basic CCD/CMOS camera. The visual light emitting from the GDD array is directed to the CCD/CMOS camera and the change in the GDD light is measured using image processing algorithms. The combination of CMOS camera and GDD focal plane arrays can yield a faster, more sensitive, and very inexpensive MMW/THz camera, eliminating the complexity of the electronic circuits and the internal electronic noise of the GDD. Furthermore, three dimensional imaging systems based on scanning prohibited real time operation of such imaging systems. This is easily solved and is economically feasible using a GDD array. This array will enable us to acquire information on distance and magnitude from all the GDD pixels in the array simultaneously. The 3D image can be obtained using methods like frequency modulation continuous wave (FMCW) direct chirp modulation, and measuring the time of flight (TOF).

Development of CCD Cameras for Soft X-ray Imaging at the National Ignition Facility

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

Teruya, A. T.; Palmer, N. E.; Schneider, M. B.

2013-09-01

The Static X-Ray Imager (SXI) is a National Ignition Facility (NIF) diagnostic that uses a CCD camera to record time-integrated X-ray images of target features such as the laser entrance hole of hohlraums. SXI has two dedicated positioners on the NIF target chamber for viewing the target from above and below, and the X-ray energies of interest are 870 eV for the “soft” channel and 3 – 5 keV for the “hard” channels. The original cameras utilize a large format back-illuminated 2048 x 2048 CCD sensor with 24 micron pixels. Since the original sensor is no longer available, an effortmore » was recently undertaken to build replacement cameras with suitable new sensors. Three of the new cameras use a commercially available front-illuminated CCD of similar size to the original, which has adequate sensitivity for the hard X-ray channels but not for the soft. For sensitivity below 1 keV, Lawrence Livermore National Laboratory (LLNL) had additional CCDs back-thinned and converted to back-illumination for use in the other two new cameras. In this paper we describe the characteristics of the new cameras and present performance data (quantum efficiency, flat field, and dynamic range) for the front- and back-illuminated cameras, with comparisons to the original cameras.« less

The development of large-aperture test system of infrared camera and visible CCD camera

NASA Astrophysics Data System (ADS)

Li, Yingwen; Geng, Anbing; Wang, Bo; Wang, Haitao; Wu, Yanying

2015-10-01

Infrared camera and CCD camera dual-band imaging system is used in many equipment and application widely. If it is tested using the traditional infrared camera test system and visible CCD test system, 2 times of installation and alignment are needed in the test procedure. The large-aperture test system of infrared camera and visible CCD camera uses the common large-aperture reflection collimator, target wheel, frame-grabber, computer which reduces the cost and the time of installation and alignment. Multiple-frame averaging algorithm is used to reduce the influence of random noise. Athermal optical design is adopted to reduce the change of focal length location change of collimator when the environmental temperature is changing, and the image quality of the collimator of large field of view and test accuracy are also improved. Its performance is the same as that of the exotic congener and is much cheaper. It will have a good market.

Typical effects of laser dazzling CCD camera

NASA Astrophysics Data System (ADS)

Zhang, Zhen; Zhang, Jianmin; Shao, Bibo; Cheng, Deyan; Ye, Xisheng; Feng, Guobin

2015-05-01

In this article, an overview of laser dazzling effect to buried channel CCD camera is given. The CCDs are sorted into staring and scanning types. The former includes the frame transfer and interline transfer types. The latter includes linear and time delay integration types. All CCDs must perform four primary tasks in generating an image, which are called charge generation, charge collection, charge transfer and charge measurement. In camera, the lenses are needed to input the optical signal to the CCD sensors, in which the techniques for erasing stray light are used. And the electron circuits are needed to process the output signal of CCD, in which many electronic techniques are used. The dazzling effects are the conjunct result of light distribution distortion and charge distribution distortion, which respectively derive from the lens and the sensor. Strictly speaking, in lens, the light distribution is not distorted. In general, the lens are so well designed and fabricated that its stray light can be neglected. But the laser is of much enough intensity to make its stray light obvious. In CCD image sensors, laser can induce a so large electrons generation. Charges transfer inefficiency and charges blooming will cause the distortion of the charge distribution. Commonly, the largest signal outputted from CCD sensor is restricted by capability of the collection well of CCD, and can't go beyond the dynamic range for the subsequent electron circuits maintaining normal work. So the signal is not distorted in the post-processing circuits. But some techniques in the circuit can make some dazzling effects present different phenomenon in final image.

Toolkit for testing scientific CCD cameras

NASA Astrophysics Data System (ADS)

Uzycki, Janusz; Mankiewicz, Lech; Molak, Marcin; Wrochna, Grzegorz

2006-03-01

The CCD Toolkit (1) is a software tool for testing CCD cameras which allows to measure important characteristics of a camera like readout noise, total gain, dark current, 'hot' pixels, useful area, etc. The application makes a statistical analysis of images saved in files with FITS format, commonly used in astronomy. A graphical interface is based on the ROOT package, which offers high functionality and flexibility. The program was developed in a way to ensure future compatibility with different operating systems: Windows and Linux. The CCD Toolkit was created for the "Pie of the Sky" project collaboration (2).

CCD Astrometry with Robotic Telescopes

NASA Astrophysics Data System (ADS)

AlZaben, Faisal; Li, Dewei; Li, Yongyao; Dennis, Aren Fene, Michael; Boyce, Grady; Boyce, Pat

2016-01-01

CCD images were acquired of three binary star systems: WDS06145+1148, WDS06206+1803, and WDS06224+2640. The astrometric solution, position angle, and separation of each system were calculated with MaximDL v6 and Mira Pro x64 software suites. The results were consistent with historical measurements in the Washington Double Star Catalog. Our analysis found some differences in measurements between single-shot color CCD cameras and traditional monochrome CCDs using a filter wheel.

An Automatic Technique for Finding Faint Moving Objects in Wide Field CCD Images

NASA Astrophysics Data System (ADS)

Hainaut, O. R.; Meech, K. J.

1996-09-01

The traditional method used to find moving objects in astronomical images is to blink pairs or series of frames after registering them to align the background objects. While this technique is extremely efficient in terms of the low signal-to-noise ratio that the human sight can detect, it proved to be extremely time-, brain- and eyesight-consuming. The wide-field images provided by the large CCD mosaic recently built at IfA cover a field of view of 20 to 30' over 8192(2) pixels. Blinking such images is an enormous task, comparable to that of blinking large photographic plates. However, as the data are available digitally (each image occupying 260Mb of disk space), we are developing a set of computer codes to perform the moving object identification in sets of frames. This poster will describe the techniques we use in order to reach a detection efficiency as good as that of a human blinker; the main steps are to find all the objects in each frame (for which we rely on ``S-Extractor'' (Bertin & Arnouts (1996), A&ASS 117, 393), then identify all the background objects, and finally to search the non-background objects for sources moving in a coherent fashion. We will also describe the results of this method applied to actual data from the 8k CCD mosaic. {This work is being supported, in part, by NSF grant AST 92-21318.}

STK: A new CCD camera at the University Observatory Jena

NASA Astrophysics Data System (ADS)

Mugrauer, M.; Berthold, T.

2010-04-01

The Schmidt-Teleskop-Kamera (STK) is a new CCD-imager, which is operated since begin of 2009 at the University Observatory Jena. This article describes the main characteristics of the new camera. The properties of the STK detector, the astrometry and image quality of the STK, as well as its detection limits at the 0.9 m telescope of the University Observatory Jena are presented. Based on observations obtained with telescopes of the University Observatory Jena, which is operated by the Astrophysical Institute of the Friedrich-Schiller-University.

Mosaic CCD method: A new technique for observing dynamics of cometary magnetospheres

NASA Technical Reports Server (NTRS)

Saito, T.; Takeuchi, H.; Kozuba, Y.; Okamura, S.; Konno, I.; Hamabe, M.; Aoki, T.; Minami, S.; Isobe, S.

1992-01-01

On April 29, 1990, the plasma tail of Comet Austin was observed with a CCD camera on the 105-cm Schmidt telescope at the Kiso Observatory of the University of Tokyo. The area of the CCD used in this observation is only about 1 sq cm. When this CCD is used on the 105-cm Schmidt telescope at the Kiso Observatory, the area corresponds to a narrow square view of 12 ft x 12 ft. By comparison with the photograph of Comet Austin taken by Numazawa (personal communication) on the same night, we see that only a small part of the plasma tail can be photographed at one time with the CCD. However, by shifting the view on the CCD after each exposure, we succeeded in imaging the entire length of the cometary magnetosphere of 1.6 x 10(exp 6) km. This new technique is called 'the mosaic CCD method'. In order to study the dynamics of cometary plasma tails, seven frames of the comet from the head to the tail region were twice imaged with the mosaic CCD method and two sets of images were obtained. Six microstructures, including arcade structures, were identified in both the images. Sketches of the plasma tail including microstructures are included.

Development of X-ray CCD camera based X-ray micro-CT system

NASA Astrophysics Data System (ADS)

Sarkar, Partha S.; Ray, N. K.; Pal, Manoj K.; Baribaddala, Ravi; Agrawal, Ashish; Kashyap, Y.; Sinha, A.; Gadkari, S. C.

2017-02-01

Availability of microfocus X-ray sources and high resolution X-ray area detectors has made it possible for high resolution microtomography studies to be performed outside the purview of synchrotron. In this paper, we present the work towards the use of an external shutter on a high resolution microtomography system using X-ray CCD camera as a detector. During micro computed tomography experiments, the X-ray source is continuously ON and owing to the readout mechanism of the CCD detector electronics, the detector registers photons reaching it during the read-out period too. This introduces a shadow like pattern in the image known as smear whose direction is defined by the vertical shift register. To resolve this issue, the developed system has been incorporated with a synchronized shutter just in front of the X-ray source. This is positioned in the X-ray beam path during the image readout period and out of the beam path during the image acquisition period. This technique has resulted in improved data quality and hence the same is reflected in the reconstructed images.

3CCD image segmentation and edge detection based on MATLAB

NASA Astrophysics Data System (ADS)

He, Yong; Pan, Jiazhi; Zhang, Yun

2006-09-01

This research aimed to identify weeds from crops in early stage in the field operation by using image-processing technology. As 3CCD images offer greater binary value difference between weed and crop section than ordinary digital images taken by common cameras. It has 3 channels (green, red, ifred) which takes a snap-photo of the same area, and the three images can be composed into one image, which facilitates the segmentation of different areas. By the application of image-processing toolkit on MATLAB, the different areas in the image can be segmented clearly. As edge detection technique is the first and very important step in image processing, The different result of different processing method was compared. Especially, by using the wavelet packet transform toolkit on MATLAB, An image was preprocessed and then the edge was extracted, and getting more clearly cut image of edge. The segmentation methods include operations as erosion, dilation and other algorithms to preprocess the images. It is of great importance to segment different areas in digital images in field real time, so as to be applied in precision farming, to saving energy and herbicide and many other materials. At present time Large scale software as MATLAB on PC was used, but the computation can be reduced and integrated into a small embed system, which means that the application of this technique in agricultural engineering is feasible and of great economical value.

Concordia CCD - A Geoscope station in continental Antarctica

NASA Astrophysics Data System (ADS)

Maggi, A.; Lévêque, J.; Thoré, J.; Bes de Berc, M.; Bernard, A.; Danesi, S.; Morelli, A.; Delladio, A.; Sorrentino, D.; Stutzmann, E.; Geoscope Team

2010-12-01

Concordia (Dome C, Antarctica) has had a permanent seismic station since 2005. It is run by EOST and INGV in collaboration with the French and Italian polar institutes (IPEV and PNRA). It is installed in an ice-vault, at 12m depth, distant 1km from the permanent scientific base at Concordia. The temperature in the vault is a constant -55°C. The data quality at the station has improved continuously since its installation. In 2007, the station was declared at ISC as an open station with station code CCD (ConCorDia), with data available upon request. It is only the second permanent station in the Antarctic continent, after South Pole. In 2010, CCD was included in the Geoscope network. Data from CCD starting in 2007 are now freely available from the Geoscope Data Center and IRIS. We present an analysis of the data quality at CCD, and describe the technical difficulties of operating an observatory-quality seismic station in the extreme environmental conditons present in continental Antarctica.

Comparison of a CCD and an APS for soft X-ray diffraction

NASA Astrophysics Data System (ADS)

Stewart, Graeme; Bates, R.; Blue, A.; Clark, A.; Dhesi, S. S.; Maneuski, D.; Marchal, J.; Steadman, P.; Tartoni, N.; Turchetta, R.

2011-12-01

We compare a new CMOS Active Pixel Sensor (APS) to a Princeton Instruments PIXIS-XO: 2048B Charge Coupled Device (CCD) with soft X-rays tested in a synchrotron beam line at the Diamond Light Source (DLS). Despite CCDs being established in the field of scientific imaging, APS are an innovative technology that offers advantages over CCDs. These include faster readout, higher operational temperature, in-pixel electronics for advanced image processing and reduced manufacturing cost. The APS employed was the Vanilla sensor designed by the MI3 collaboration and funded by an RCUK Basic technology grant. This sensor has 520 x 520 square pixels, of size 25 μm on each side. The sensor can operate at a full frame readout of up to 20 Hz. The sensor had been back-thinned, to the epitaxial layer. This was the first time that a back-thinned APS had been demonstrated at a beam line at DLS. In the synchrotron experiment soft X-rays with an energy of approximately 708 eV were used to produce a diffraction pattern from a permalloy sample. The pattern was imaged at a range of integration times with both sensors. The CCD had to be operated at a temperature of -55°C whereas the Vanilla was operated over a temperature range from 20°C to -10°C. We show that the APS detector can operate with frame rates up to two hundred times faster than the CCD, without excessive degradation of image quality. The signal to noise of the APS is shown to be the same as that of the CCD at identical integration times and the response is shown to be linear, with no charge blooming effects. The experiment has allowed a direct comparison of back thinned APS and CCDs in a real soft x-ray synchrotron experiment.

CCD centroiding analysis for Nano-JASMINE observation data

NASA Astrophysics Data System (ADS)

Niwa, Yoshito; Yano, Taihei; Araki, Hiroshi; Gouda, Naoteru; Kobayashi, Yukiyasu; Yamada, Yoshiyuki; Tazawa, Seiichi; Hanada, Hideo

2010-07-01

Nano-JASMINE is a very small satellite mission for global space astrometry with milli-arcsecond accuracy, which will be launched in 2011. In this mission, centroids of stars in CCD image frames are estimated with sub-pixel accuracy. In order to realize such a high precision centroiding an algorithm utilizing a least square method is employed. One of the advantages is that centroids can be calculated without explicit assumption of the point spread functions of stars. CCD centroiding experiment has been performed to investigate whether this data analysis is available, and centroids of artificial star images on a CCD are determined with a precision of less than 0.001 pixel. This result indicates parallaxes of stars within 300 pc from Sun can be observed in Nano-JASMINE.

Printed circuit board for a CCD camera head

DOEpatents

Conder, Alan D.

2002-01-01

A charge-coupled device (CCD) camera head which can replace film for digital imaging of visible light, ultraviolet radiation, and soft to penetrating x-rays, such as within a target chamber where laser produced plasmas are studied. The camera head is small, capable of operating both in and out of a vacuum environment, and is versatile. The CCD camera head uses PC boards with an internal heat sink connected to the chassis for heat dissipation, which allows for close (0.04" for example) stacking of the PC boards. Integration of this CCD camera head into existing instrumentation provides a substantial enhancement of diagnostic capabilities for studying high energy density plasmas, for a variety of military industrial, and medical imaging applications.

The SMILE Soft X-ray Imager (SXI) CCD design and development

NASA Astrophysics Data System (ADS)

Soman, M. R.; Hall, D. J.; Holland, A. D.; Burgon, R.; Buggey, T.; Skottfelt, J.; Sembay, S.; Drumm, P.; Thornhill, J.; Read, A.; Sykes, J.; Walton, D.; Branduardi-Raymont, G.; Kennedy, T.; Raab, W.; Verhoeve, P.; Agnolon, D.; Woffinden, C.

2018-01-01

SMILE, the Solar wind Magnetosphere Ionosphere Link Explorer, is a joint science mission between the European Space Agency and the Chinese Academy of Sciences. The spacecraft will be uniquely equipped to study the interaction between the Earth's magnetosphere-ionosphere system and the solar wind on a global scale. SMILE's instruments will explore this science through imaging of the solar wind charge exchange soft X-ray emission from the dayside magnetosheath, simultaneous imaging of the UV northern aurora and in-situ monitoring of the solar wind and magnetosheath plasma and magnetic field conditions. The Soft X-ray Imager (SXI) is the instrument being designed to observe X-ray photons emitted by the solar wind charge exchange process at photon energies between 200 eV and 2000 eV . X-rays will be collected using a focal plane array of two custom-designed CCDs, each consisting of 18 μm square pixels in a 4510 by 4510 array. SMILE will be placed in a highly elliptical polar orbit, passing in and out of the Earth's radiation belts every 48 hours. Radiation damage accumulated in the CCDs during the mission's nominal 3-year lifetime will degrade their performance (such as through decreases in charge transfer efficiency), negatively impacting the instrument's ability to detect low energy X-rays incident on the regions of the CCD image area furthest from the detector outputs. The design of the SMILE-SXI CCDs is presented here, including features and operating methods for mitigating the effects of radiation damage and expected end of life CCD performance. Measurements with a PLATO device that has not been designed for soft X-ray signal levels indicate a temperature-dependent transfer efficiency performance varying between 5×10-5 and 9×10-4 at expected End of Life for 5.9 keV photons, giving an initial set of measurements from which to extrapolate the performance of the SXI CCDs.

Sensors for 3D Imaging: Metric Evaluation and Calibration of a CCD/CMOS Time-of-Flight Camera.

PubMed

Chiabrando, Filiberto; Chiabrando, Roberto; Piatti, Dario; Rinaudo, Fulvio

2009-01-01

3D imaging with Time-of-Flight (ToF) cameras is a promising recent technique which allows 3D point clouds to be acquired at video frame rates. However, the distance measurements of these devices are often affected by some systematic errors which decrease the quality of the acquired data. In order to evaluate these errors, some experimental tests on a CCD/CMOS ToF camera sensor, the SwissRanger (SR)-4000 camera, were performed and reported in this paper. In particular, two main aspects are treated: the calibration of the distance measurements of the SR-4000 camera, which deals with evaluation of the camera warm up time period, the distance measurement error evaluation and a study of the influence on distance measurements of the camera orientation with respect to the observed object; the second aspect concerns the photogrammetric calibration of the amplitude images delivered by the camera using a purpose-built multi-resolution field made of high contrast targets.

Characterization of a 512x512-pixel 8-output full-frame CCD for high-speed imaging

NASA Astrophysics Data System (ADS)

Graeve, Thorsten; Dereniak, Eustace L.

1993-01-01

The characterization of a 512 by 512 pixel, eight-output full frame CCD manufactured by English Electric Valve under part number CCD13 is discussed. This device is a high- resolution Silicon-based array designed for visible imaging applications at readout periods as low as two milliseconds. The characterization of the device includes mean-variance analysis to determine read noise and dynamic range, as well as charge transfer efficiency, MTF, and quantum efficiency measurements. Dark current and non-uniformity issues on a pixel-to-pixel basis and between individual outputs are also examined. The characterization of the device is restricted by hardware limitations to a one MHz pixel rate, corresponding to a 40 ms readout time. However, subsections of the device have been operated at up to an equivalent 100 frames per second. To maximize the frame rate, the CCD is illuminated by a synchronized strobe flash in between frame readouts. The effects of the strobe illumination on the imagery obtained from the device is discussed.

Modeling the impact of preflushing on CTE in proton irradiated CCD-based detectors

NASA Astrophysics Data System (ADS)

Philbrick, R. H.

2002-04-01

A software model is described that performs a "real world" simulation of the operation of several types of charge-coupled device (CCD)-based detectors in order to accurately predict the impact that high-energy proton radiation has on image distortion and modulation transfer function (MTF). The model was written primarily to predict the effectiveness of vertical preflushing on the custom full frame CCD-based detectors intended for use on the proposed Kepler Discovery mission, but it is capable of simulating many other types of CCD detectors and operating modes as well. The model keeps track of the occupancy of all phosphorous-silicon (P-V), divacancy (V-V) and oxygen-silicon (O-V) defect centers under every CCD electrode over the entire detector area. The integrated image is read out by simulating every electrode-to-electrode charge transfer in both the vertical and horizontal CCD registers. A signal level dependency on the capture and emission of signal is included and the current state of each electrode (e.g., barrier or storage) is considered when distributing integrated and emitted signal. Options for performing preflushing, preflashing, and including mini-channels are available on both the vertical and horizontal CCD registers. In addition, dark signal generation and image transfer smear can be selectively enabled or disabled. A comparison of the charge transfer efficiency (CTE) data measured on the Hubble space telescope imaging spectrometer (STIS) CCD with the CTE extracted from model simulations of the STIS CCD show good agreement.

Occultation Predictions Using CCD Strip-Scanning Astrometry

NASA Technical Reports Server (NTRS)

Dunham, Edward W.; Ford, C. H.; Stone, R. P. S.; McDonald, S. W.; Olkin, C. B.; Elliot, J. L.; Witteborn, Fred C. (Technical Monitor)

1994-01-01

We are developing the method of CCD strip-scanning astrometry for the purpose of deriving reliable advance predictions for occultations involving small objects in the outer solar system. We are using a camera system based on a Ford/Loral 2Kx2K CCD with the Crossley telescope at Lick Observatory for this work. The columns of die CCD are aligned East-West, the telescope drive is stopped, and the CCD is clocked at the same rate that the stars drift across it. In this way we obtain arbitrary length strip images 20 arcmin wide with 0.58" pixels. Since planets move mainly in RA, it is possible to obtain images of the planet and star to be occulted on the same strip well before the occultation occurs. The strip-to-strip precision (i.e. reproducibility) of positions is limited by atmospheric image motion to about 0.1" rms per strip. However, for objects that are nearby in R.A., the image motion is highly correlated and their relative positions are good to 0.02" rms per strip. We will show that the effects of atmospheric image motion on a given strip can be removed if a sufficient number of strips of a given area have been obtained. Thus, it is possible to reach an rms precision of 0.02" per strip, corresponding to about 0.3 of Pluto or Triton's angular radius. The ultimate accuracy of a prediction based on strip-scanning astrometry is currently limited by the accuracy of the positions of the stars in the astrometric network used and by systematic errors most likely due to the optical system. We will show the results of . the prediction of some recent occultations as examples of the current capabilities and limitations of this technique.

CCD sensors in synchrotron X-ray detectors

NASA Astrophysics Data System (ADS)

Strauss, M. G.; Naday, I.; Sherman, I. S.; Kraimer, M. R.; Westbrook, E. M.; Zaluzec, N. J.

1988-04-01

The intense photon flux from advanced synchrotron light sources, such as the 7-GeV synchrotron being designed at Argonne, require integrating-type detectors. Charge-coupled devices (CCDs) are well suited as synchrotron X-ray detectors. When irradiated indirectly via a phosphor followed by reducing optics, diffraction patterns of 100 cm 2 can be imaged on a 2 cm 2 CCD. With a conversion efficiency of ˜ 1 CCD electron/X-ray photon, a peak saturation capacity of > 10 6 X-rays can be obtained. A programmable CCD controller operating at a clock frequency of 20 MHz has been developed. The readout rate is 5 × 10 6 pixels/s and the shift rate in the parallel registers is 10 6 lines/s. The test detector was evaluated in two experiments. In protein crystallography diffraction patterns have been obtained from a lysozyme crystal using a conventional rotating anode X-ray generator. Based on these results we expect to obtain at a synchrotron diffraction images at a rate of ˜ 1 frame/s or a complete 3-dimensional data set from a single crystal in ˜ 2 min. In electron energy-loss spectroscopy (EELS), the CCD was used in a parallel detection mode which is similar to the mode array detectors are used in dispersive EXAFS. With a beam current corresponding to 3 × 10 9 electron/s on the detector, a series of 64 spectra were recorded on the CCD in a continuous sequence without interruption due to readout. The frame-to-frame pixel signal fluctuations had σ = 0.4% from which DQE = 0.4 was obtained, where the detector conversion efficiency was 2.6 CCD electrons/X-ray photon. These multiple frame series also showed the time-resolved modulation of the electron microscope optics by stray magnetic fields.

CCD Camera Detection of HIV Infection.

PubMed

Day, John R

2017-01-01

Rapid and precise quantification of the infectivity of HIV is important for molecular virologic studies, as well as for measuring the activities of antiviral drugs and neutralizing antibodies. An indicator cell line, a CCD camera, and image-analysis software are used to quantify HIV infectivity. The cells of the P4R5 line, which express the receptors for HIV infection as well as β-galactosidase under the control of the HIV-1 long terminal repeat, are infected with HIV and then incubated 2 days later with X-gal to stain the infected cells blue. Digital images of monolayers of the infected cells are captured using a high resolution CCD video camera and a macro video zoom lens. A software program is developed to process the images and to count the blue-stained foci of infection. The described method allows for the rapid quantification of the infected cells over a wide range of viral inocula with reproducibility, accuracy and at relatively low cost.

CCD Centroiding Experiment for Correcting a Distorted Image on the Focal Plane

NASA Astrophysics Data System (ADS)

Yano, Taihei; Araki, Hiroshi; Gouda, Naoteru; Kobayashi, Yukiyasu; Tsujimoto, Takuji; Nakajima, Tadashi; Kawano, Nobuyuki; Tazawa, Seiichi; Yamada, Yoshiyuki; Hanada, Hideo; Asari, Kazuyoshi; Tsuruta, Seiitsu

2006-10-01

JASMINE (Japan Astrometry Satellite Mission for Infrared Exploration) and ILOM (In situ Lunar Orientation Measurement) are space missions that are in progress at the National Astronomical Observatory of Japan. These two projects require a common astrometric technique to obtain precise positions of star images on solid-state detectors in order to accomplish their objectives. In the laboratory, we have carried out measurements of the centroid of artificial star images on a CCD array in order to investigate the precision of the positions of the stars, using an algorithm for estimating them from photon-weighted means of the stars. In the calibration of the position of a star image at the focal plane, we have also taken into account the lowest order distortion due to optical aberrations, which is proportional to the cube of the distance from the optical axis. Accordingly, we find that the precision of the measurement for the positions of the stars reaches below 1/100 pixel for one measurement.

Timing generator of scientific grade CCD camera and its implementation based on FPGA technology

NASA Astrophysics Data System (ADS)

Si, Guoliang; Li, Yunfei; Guo, Yongfei

2010-10-01

The Timing Generator's functions of Scientific Grade CCD Camera is briefly presented: it generates various kinds of impulse sequence for the TDI-CCD, video processor and imaging data output, acting as the synchronous coordinator for time in the CCD imaging unit. The IL-E2TDI-CCD sensor produced by DALSA Co.Ltd. use in the Scientific Grade CCD Camera. Driving schedules of IL-E2 TDI-CCD sensor has been examined in detail, the timing generator has been designed for Scientific Grade CCD Camera. FPGA is chosen as the hardware design platform, schedule generator is described with VHDL. The designed generator has been successfully fulfilled function simulation with EDA software and fitted into XC2VP20-FF1152 (a kind of FPGA products made by XILINX). The experiments indicate that the new method improves the integrated level of the system. The Scientific Grade CCD camera system's high reliability, stability and low power supply are achieved. At the same time, the period of design and experiment is sharply shorted.

Advances in CCD detector technology for x-ray diffraction applications

NASA Astrophysics Data System (ADS)

Thorson, Timothy A.; Durst, Roger D.; Frankel, Dan; Bordwell, Rex L.; Camara, Jose R.; Leon-Guerrero, Edward; Onishi, Steven K.; Pang, Francis; Vu, Paul; Westbrook, Edwin M.

2004-01-01

Phosphor-coupled CCDs are established as one of the most successful technologies for x-ray diffraction. This application demands that the CCD simultaneously achieve both the highest possible sensitivity and high readout speeds. Recently, wafer-scale, back illuminated devices have become available which offer significantly higher quantum efficiency than conventional devices (the Fairchild Imaging CCD 486 BI). However, since back thinning significantly changes the electrical properties of the CCD the high speed operation of wafer-scale, back-illuminated devices is not well understood. Here we describe the operating characteristics (including noise, linearity, full well capacity and CTE) of the back-illuminated CCD 486 at readout speeds up to 4 MHz.

Multiport backside-illuminated CCD imagers for high-frame-rate camera applications

NASA Astrophysics Data System (ADS)

Levine, Peter A.; Sauer, Donald J.; Hseuh, Fu-Lung; Shallcross, Frank V.; Taylor, Gordon C.; Meray, Grazyna M.; Tower, John R.; Harrison, Lorna J.; Lawler, William B.

1994-05-01

Two multiport, second-generation CCD imager designs have been fabricated and successfully tested. They are a 16-port 512 X 512 array and a 32-port 1024 X 1024 array. Both designs are back illuminated, have on-chip CDS, lateral blooming control, and use a split vertical frame transfer architecture with full frame storage. The 512 X 512 device has been operated at rates over 800 frames per second. The 1024 X 1024 device has been operated at rates over 300 frames per second. The major changes incorporated in the second-generation design are, reduction in gate length in the output area to give improved high-clock-rate performance, modified on-chip CDS circuitry for reduced noise, and optimized implants to improve performance of blooming control at lower clock amplitude. This paper discusses the imager design improvements and presents measured performance results at high and moderate frame rates. The design and performance of three moderate frame rate cameras are discussed.

Hybrid imaging: a quantum leap in scientific imaging

NASA Astrophysics Data System (ADS)

Atlas, Gene; Wadsworth, Mark V.

2004-01-01

ImagerLabs has advanced its patented next generation imaging technology called the Hybrid Imaging Technology (HIT) that offers scientific quality performance. The key to the HIT is the merging of the CCD and CMOS technologies through hybridization rather than process integration. HIT offers exceptional QE, fill factor, broad spectral response and very low noise properties of the CCD. In addition, it provides the very high-speed readout, low power, high linearity and high integration capability of CMOS sensors. In this work, we present the benefits, and update the latest advances in the performance of this exciting technology.

Dynamic imaging with a triggered and intensified CCD camera system in a high-intensity neutron beam

NASA Astrophysics Data System (ADS)

Vontobel, P.; Frei, G.; Brunner, J.; Gildemeister, A. E.; Engelhardt, M.

2005-04-01

When time-dependent processes within metallic structures should be inspected and visualized, neutrons are well suited due to their high penetration through Al, Ag, Ti or even steel. Then it becomes possible to inspect the propagation, distribution and evaporation of organic liquids as lubricants, fuel or water. The principle set-up of a suited real-time system was implemented and tested at the radiography facility NEUTRA of PSI. The highest beam intensity there is 2×107 cm s, which enables to observe sequences in a reasonable time and quality. The heart of the detection system is the MCP intensified CCD camera PI-Max with a Peltier cooled chip (1300×1340 pixels). The intensifier was used for both gating and image enhancement, where as the information was accumulated over many single frames on the chip before readout. Although, a 16-bit dynamic range is advertised by the camera manufacturers, it must be less due to the inherent noise level from the intensifier. The obtained result should be seen as the starting point to go ahead to fit the different requirements of car producers in respect to fuel injection, lubricant distribution, mechanical stability and operation control. Similar inspections will be possible for all devices with repetitive operation principle. Here, we report about two measurements dealing with the lubricant distribution in a running motorcycle motor turning at 1200 rpm. We were monitoring the periodic stationary movements of piston, valves and camshaft with a micro-channel plate intensified CCD camera system (PI-Max 1300RB, Princeton Instruments) triggered at exactly chosen time points.

CCD radiation damage in ESA Cosmic Visions missions: assessment and mitigation

NASA Astrophysics Data System (ADS)

Lumb, David H.

2009-08-01

Charge Coupled Device (CCD) imagers have been widely used in space-borne astronomical instruments. A frequent concern has been the radiation damage effects on the CCD charge transfer properties. We review some methods for assessing the Charge Transfer Inefficiency (CTI) in CCDs. Techniques to minimise degradation using background charge injection and p-channel CCD architectures are discussed. A critical review of the claims for p-channel architectures is presented. The performance advantage for p-channel CCD performance is shown to be lower than claimed previously. Finally we present some projections for the performance in the context of some future ESA missions.

Active Pixel Sensors: Are CCD's Dinosaurs?

NASA Technical Reports Server (NTRS)

Fossum, Eric R.

1993-01-01

Charge-coupled devices (CCD's) are presently the technology of choice for most imaging applications. In the 23 years since their invention in 1970, they have evolved to a sophisticated level of performance. However, as with all technologies, we can be certain that they will be supplanted someday. In this paper, the Active Pixel Sensor (APS) technology is explored as a possible successor to the CCD. An active pixel is defined as a detector array technology that has at least one active transistor within the pixel unit cell. The APS eliminates the need for nearly perfect charge transfer -- the Achilles' heel of CCDs. This perfect charge transfer makes CCD's radiation 'soft,' difficult to use under low light conditions, difficult to manufacture in large array sizes, difficult to integrate with on-chip electronics, difficult to use at low temperatures, difficult to use at high frame rates, and difficult to manufacture in non-silicon materials that extend wavelength response.

Solid state television camera (CCD-buried channel)

NASA Technical Reports Server (NTRS)

1976-01-01

The development of an all solid state television camera, which uses a buried channel charge coupled device (CCD) as the image sensor, was undertaken. A 380 x 488 element CCD array is utilized to ensure compatibility with 525 line transmission and display monitor equipment. Specific camera design approaches selected for study and analysis included (a) optional clocking modes for either fast (1/60 second) or normal (1/30 second) frame readout, (b) techniques for the elimination or suppression of CCD blemish effects, and (c) automatic light control and video gain control (i.e., ALC and AGC) techniques to eliminate or minimize sensor overload due to bright objects in the scene. Preferred approaches were determined and integrated into a deliverable solid state TV camera which addressed the program requirements for a prototype qualifiable to space environment conditions.

Blinded evaluation of the effects of high definition and magnification on perceived image quality in laryngeal imaging.

PubMed

Otto, Kristen J; Hapner, Edie R; Baker, Michael; Johns, Michael M

2006-02-01

Advances in commercial video technology have improved office-based laryngeal imaging. This study investigates the perceived image quality of a true high-definition (HD) video camera and the effect of magnification on laryngeal videostroboscopy. We performed a prospective, dual-armed, single-blinded analysis of a standard laryngeal videostroboscopic examination comparing 3 separate add-on camera systems: a 1-chip charge-coupled device (CCD) camera, a 3-chip CCD camera, and a true 720p (progressive scan) HD camera. Displayed images were controlled for magnification and image size (20-inch [50-cm] display, red-green-blue, and S-video cable for 1-chip and 3-chip cameras; digital visual interface cable and HD monitor for HD camera). Ten blinded observers were then asked to rate the following 5 items on a 0-to-100 visual analog scale: resolution, color, ability to see vocal fold vibration, sense of depth perception, and clarity of blood vessels. Eight unblinded observers were then asked to rate the difference in perceived resolution and clarity of laryngeal examination images when displayed on a 10-inch (25-cm) monitor versus a 42-inch (105-cm) monitor. A visual analog scale was used. These monitors were controlled for actual resolution capacity. For each item evaluated, randomized block design analysis demonstrated that the 3-chip camera scored significantly better than the 1-chip camera (p < .05). For the categories of color and blood vessel discrimination, the 3-chip camera scored significantly better than the HD camera (p < .05). For magnification alone, observers rated the 42-inch monitor statistically better than the 10-inch monitor. The expense of new medical technology must be judged against its added value. This study suggests that HD laryngeal imaging may not add significant value over currently available video systems, in perceived image quality, when a small monitor is used. Although differences in clarity between standard and HD cameras may not be readily

CCD TV focal plane guider development and comparison to SIRTF applications

NASA Technical Reports Server (NTRS)

Rank, David M.

1989-01-01

It is expected that the SIRTF payload will use a CCD TV focal plane fine guidance sensor to provide acquisition of sources and tracking stability of the telescope. Work has been done to develop CCD TV cameras and guiders at Lick Observatory for several years and have produced state of the art CCD TV systems for internal use. NASA decided to provide additional support so that the limits of this technology could be established and a comparison between SIRTF requirements and practical systems could be put on a more quantitative basis. The results of work carried out at Lick Observatory which was designed to characterize present CCD autoguiding technology and relate it to SIRTF applications is presented. Two different design types of CCD cameras were constructed using virtual phase and burred channel CCD sensors. A simple autoguider was built and used on the KAO, Mt. Lemon and Mt. Hamilton telescopes. A video image processing system was also constructed in order to characterize the performance of the auto guider and CCD cameras.

The CTIO Acquisition CCD-TV camera design

NASA Astrophysics Data System (ADS)

Schmidt, Ricardo E.

1990-07-01

A CCD-based Acquisition TV Camera has been developed at CTIO to replace the existing ISIT units. In a 60 second exposure, the new Camera shows a sixfold improvement in sensitivity over an ISIT used with a Leaky Memory. Integration times can be varied over a 0.5 to 64 second range. The CCD, contained in an evacuated enclosure, is operated at -45 C. Only the image section, an area of 8.5 mm x 6.4 mm, gets exposed to light. Pixel size is 22 microns and either no binning or 2 x 2 binning can be selected. The typical readout rates used vary between 3.5 and 9 microseconds/pixel. Images are stored in a PC/XT/AT, which generates RS-170 video. The contrast in the RS-170 frames is automatically enhanced by the software.

Design of a CCD Camera for Space Surveillance

DTIC Science & Technology

2016-03-05

Laboratory fabricated CCID-51M, a 2048x1024 pixel Charge Couple Device (CCD) imager. [1] The mission objective is to observe and detect satellites in...phased to transfer the charge to the outputs. An electronic shutter is created by having an equal area of pixels covered by an opaque metal mask. The...Figure 4 CDS Timing Diagram By design the CCD readout rate is 400 KHz. This rate was chosen so reading the 2E6 pixels from one output is less than

Research of optical coherence tomography microscope based on CCD detector

NASA Astrophysics Data System (ADS)

Zhang, Hua; Xu, Zhongbao; Zhang, Shuomo

2008-12-01

The reference wave phase was modulated with a sinusoidal vibrating mirror attached to a Piezoelectric Transducer (PZT), the integration was performed by a CCD, and the charge storage period of the CCD image sensor was one-quarter period of the sinusoidal phase modulation. With the frequency- synchronous detection technique, four images (four frames of interference pattern) were recorded during one period of the phase modulation. In order to obtain the optimum modulation parameter, the values of amplitude and phase of the sinusoidal phase modulation were determined by considering the measurement error caused by the additive noise contained in the detected values. The PZT oscillation was controlled by a closed loop control system based on PID controller. An ideal discrete digital sine function at 50Hz with adjustable amplitude was used to adjust the vibrating of PZT, and a digital phase shift techniques was used to adjust vibrating phase of PZT so that the phase of the modulation could reach their optimum values. The CCD detector was triggered with software at 200Hz. Based on work above a small coherent signal masked by the preponderant incoherent background with a CCD detector was obtained.

Soft X-ray and XUV imaging with a charge-coupled device /CCD/-based detector

NASA Technical Reports Server (NTRS)

Loter, N. G.; Burstein, P.; Krieger, A.; Ross, D.; Harrison, D.; Michels, D. J.

1981-01-01

A soft X-ray/XUV imaging camera which uses a thinned, back-illuminated, all-buried channel RCA CCD for radiation sensing has been built and tested. The camera is a slow-scan device which makes possible frame integration if necessary. The detection characteristics of the device have been tested over the 15-1500 eV range. The response was linear with exposure up to 0.2-0.4 erg/sq cm; saturation occurred at greater exposures. Attention is given to attempts to resolve single photons with energies of 1.5 keV.

First-light instrument for the 3.6-m Devasthal Optical Telescope: 4Kx4K CCD Imager

NASA Astrophysics Data System (ADS)

Pandey, Shashi Bhushan; Yadav, Rama Kant Singh; Nanjappa, Nandish; Yadav, Shobhit; Reddy, Bheemireddy Krishna; Sahu, Sanjit; Srinivasan, Ramaiyengar

2018-04-01

As a part of in-house instrument developmental activity at ARIES, the 4Kx4K CCD Imager is designed and developed as a first-light instrument for the axial port of the 3.6-m Devasthal Optical Telescope (DOT). The f/9 beam of the telescope having a plate-scale of 6.4"/mm is utilized to conduct deeper photom-etry within the central 10' field of view. The pixel size of the blue-enhanced liquid nitrogen cooled STA4150 4Kx4K CCD chip is 15 μm, with options to select gain and speed values to utilize the dynamic range. Using the Imager, it is planned to image the central 6.5'x6.5' field of view of the telescope for various science goals by getting deeper images in several broad-band filters for point sources and objects with low surface brightness. The fully assembled Imager along with automated filter wheels having Bessel UBV RI and SDSS ugriz filters was tested in late 2015 at the axial port of the 3.6-m DOT. This instrument was finally mounted at the axial port of the 3.6-m DOT on 30 March 2016 when the telescope was technically activated jointly by the Prime Ministers of India and Belgium. It is expected to serve as a general purpose multi-band deep imaging instrument for a variety of science goals including studies of cosmic transients, active galaxies, star clusters and optical monitoring of X-ray sources discovered by the newly launched Indian space-mission called ASTROSAT, and follow-up of radio bright objects discovered by the Giant Meterwave Radio Telescope.

CCD correlation techniques

NASA Technical Reports Server (NTRS)

Hewes, C. R.; Bosshart, P. W.; Eversole, W. L.; Dewit, M.; Buss, D. D.

1976-01-01

Two CCD techniques were discussed for performing an N-point sampled data correlation between an input signal and an electronically programmable reference function. The design and experimental performance of an implementation of the direct time correlator utilizing two analog CCDs and MOS multipliers on a single IC were evaluated. The performance of a CCD implementation of the chirp z transform was described, and the design of a new CCD integrated circuit for performing correlation by multiplication in the frequency domain was presented. This chip provides a discrete Fourier transform (DFT) or inverse DFT, multipliers, and complete support circuitry for the CCD CZT. The two correlation techniques are compared.

Curved CCD detector devices and arrays for multispectral astrophysical applications and terrestrial stereo panoramic cameras

NASA Astrophysics Data System (ADS)

Swain, Pradyumna; Mark, David

2004-09-01

The emergence of curved CCD detectors as individual devices or as contoured mosaics assembled to match the curved focal planes of astronomical telescopes and terrestrial stereo panoramic cameras represents a major optical design advancement that greatly enhances the scientific potential of such instruments. In altering the primary detection surface within the telescope"s optical instrumentation system from flat to curved, and conforming the applied CCD"s shape precisely to the contour of the telescope"s curved focal plane, a major increase in the amount of transmittable light at various wavelengths through the system is achieved. This in turn enables multi-spectral ultra-sensitive imaging with much greater spatial resolution necessary for large and very large telescope applications, including those involving infrared image acquisition and spectroscopy, conducted over very wide fields of view. For earth-based and space-borne optical telescopes, the advent of curved CCD"s as the principle detectors provides a simplification of the telescope"s adjoining optics, reducing the number of optical elements and the occurrence of optical aberrations associated with large corrective optics used to conform to flat detectors. New astronomical experiments may be devised in the presence of curved CCD applications, in conjunction with large format cameras and curved mosaics, including three dimensional imaging spectroscopy conducted over multiple wavelengths simultaneously, wide field real-time stereoscopic tracking of remote objects within the solar system at high resolution, and deep field survey mapping of distant objects such as galaxies with much greater multi-band spatial precision over larger sky regions. Terrestrial stereo panoramic cameras equipped with arrays of curved CCD"s joined with associative wide field optics will require less optical glass and no mechanically moving parts to maintain continuous proper stereo convergence over wider perspective viewing fields than

Dosimetry of heavy ions by use of CCD detectors

NASA Technical Reports Server (NTRS)

Schott, J. U.

1994-01-01

The design and the atomic composition of Charge Coupled Devices (CCD's) make them unique for investigations of single energetic particle events. As detector system for ionizing particles they detect single particles with local resolution and near real time particle tracking. In combination with its properties as optical sensor, particle transversals of single particles are to be correlated to any objects attached to the light sensitive surface of the sensor by simple imaging of their shadow and subsequent image analysis of both, optical image and particle effects, observed in affected pixels. With biological objects it is possible for the first time to investigate effects of single heavy ions in tissue or extinguished organs of metabolizing (i.e. moving) systems with a local resolution better than 15 microns. Calibration data for particle detection in CCD's are presented for low energetic protons and heavy ions.

Very-large-area CCD image sensors: concept and cost-effective research

NASA Astrophysics Data System (ADS)

Bogaart, E. W.; Peters, I. M.; Kleimann, A. C.; Manoury, E. J. P.; Klaassens, W.; de Laat, W. T. F. M.; Draijer, C.; Frost, R.; Bosiers, J. T.

2009-01-01

A new-generation full-frame 36x48 mm2 48Mp CCD image sensor with vertical anti-blooming for professional digital still camera applications is developed by means of the so-called building block concept. The 48Mp devices are formed by stitching 1kx1k building blocks with 6.0 µm pixel pitch in 6x8 (hxv) format. This concept allows us to design four large-area (48Mp) and sixty-two basic (1Mp) devices per 6" wafer. The basic image sensor is relatively small in order to obtain data from many devices. Evaluation of the basic parameters such as the image pixel and on-chip amplifier provides us statistical data using a limited number of wafers. Whereas the large-area devices are evaluated for aspects typical to large-sensor operation and performance, such as the charge transport efficiency. Combined with the usability of multi-layer reticles, the sensor development is cost effective for prototyping. Optimisation of the sensor design and technology has resulted in a pixel charge capacity of 58 ke- and significantly reduced readout noise (12 electrons at 25 MHz pixel rate, after CDS). Hence, a dynamic range of 73 dB is obtained. Microlens and stack optimisation resulted in an excellent angular response that meets with the wide-angle photography demands.

Performance characteristics of CCDs for the ACIS experiment. [Advanced X-ray Astrophysics Facility CCD Imaging Spectrometer

NASA Technical Reports Server (NTRS)

Garmire, Gordon P.; Nousek, John; Burrows, David; Ricker, George; Bautz, Mark; Doty, John; Collins, Stewart; Janesick, James

1988-01-01

The search for the optimum CCD to be used at the focal surface of the Advanced X-ray Astrophysics Facility (AXAF) is described. The physics of the interaction of X-rays in silicon through the photoelectric effect is reviewed. CCD technology at the beginning of the AXAF definition phase is summarized, and the results of the CCD enhancement program are discussed. Other sources of optimum CCDs are examined, and CCD enhancements made at MIT Lincoln Laboratory are addressed.

Thinning and mounting a Texas Instruments 3-phase CCD

NASA Technical Reports Server (NTRS)

Lesser, M. P.; Leach, R. W.; Angel, J. R. P.

1986-01-01

Thin CCDs with precise control of thickness and surface quality allow astronomers to optimize chips for specific applications. A means of mechanically thinning a TI 800 x 800 CCD with an abrasive slurry of aluminum oxide is presented. Using the same techniques, the abrasives can be replaced with a chemical solution to eliminate subsurface damage. A technique of mounting the CCD which retains the high quality surface generated during thinning is also demonstrated. This requires the backside of the chip to be bonded to a glass window which closely matches silicon's thermal expansion properties. Thinned CCDs require backside treatment to enhance blue and UV quantum efficiency. Two methods are discussed which may be effective with this mounting system.

Solid state television camera (CCD-buried channel), revision 1

NASA Technical Reports Server (NTRS)

1977-01-01

An all solid state television camera was designed which uses a buried channel charge coupled device (CCD) as the image sensor. A 380 x 488 element CCD array is utilized to ensure compatibility with 525-line transmission and display monitor equipment. Specific camera design approaches selected for study and analysis included (1) optional clocking modes for either fast (1/60 second) or normal (1/30 second) frame readout, (2) techniques for the elimination or suppression of CCD blemish effects, and (3) automatic light control and video gain control techniques to eliminate or minimize sensor overload due to bright objects in the scene. Preferred approaches were determined and integrated into a deliverable solid state TV camera which addressed the program requirements for a prototype qualifiable to space environment conditions.

A CCD Spectrometer for One Dollar

NASA Astrophysics Data System (ADS)

Beaver, J.; Robert, D.

2011-09-01

We describe preliminary tests on a very low-cost system for obtaining stellar spectra for instructional use in an introductory astronomy laboratory. CCD imaging with small telescopes is now commonplace and relatively inexpensive. Giving students direct experience taking stellar spectra, however, is much more difficult, and the equipment can easily be out of reach for smaller institutions, especially if one wants to give the experience to large numbers of students. We have performed preliminary tests on an extremely low-cost (about $1.00) objective grating that can be coupled with an existing CCD camera or commercial digital single-lens reflex (DSLR) camera and a small telescope typical of introductory astronomy labs. With this equipment we believe it is possible for introductory astronomy students to take stellar spectra that are of high enough quality to distinguish between many MK spectral classes, or to determine standard B and V magnitudes. We present observational tests of this objective grating used on an 8" Schmidt-Cassegrain with a low-end, consumer DSLR camera. Some low-cost strategies for reducing the raw data are compared, with an eye toward projects ranging from individual undergraduate research projects to use by many students in a non-majors introductory astronomy lab. Toward this end we compare various trade offs between complexity of the observing and data reduction processes and the usefulness of the final results. We also describe some undergraduate astronomy education projects that this system could potentially be used for. Some of these projects could involve data-sharing collaborations between students at different institutions.

Solid state, CCD-buried channel, television camera study and design

NASA Technical Reports Server (NTRS)

Hoagland, K. A.; Balopole, H.

1976-01-01

An investigation of an all solid state television camera design, which uses a buried channel charge-coupled device (CCD) as the image sensor, was undertaken. A 380 x 488 element CCD array was utilized to ensure compatibility with 525 line transmission and display monitor equipment. Specific camera design approaches selected for study and analysis included (a) optional clocking modes for either fast (1/60 second) or normal (1/30 second) frame readout, (b) techniques for the elimination or suppression of CCD blemish effects, and (c) automatic light control and video gain control techniques to eliminate or minimize sensor overload due to bright objects in the scene. Preferred approaches were determined and integrated into a design which addresses the program requirements for a deliverable solid state TV camera.

Radio-Optical Reference Frame Link Using the U.S. Naval Observatory Astrograph and Deep CCD Imaging

NASA Astrophysics Data System (ADS)

Zacharias, N.; Zacharias, M. I.

2014-05-01

Between 1997 and 2004 several observing runs were conducted, mainly with the CTIO 0.9 m, to image International Celestial Reference Frame (ICRF) counterparts (mostly QSOs) in order to determine accurate optical positions. Contemporary to these deep CCD images, the same fields were observed with the U.S. Naval Observatory astrograph in the same bandpass. They provide accurate positions on the Hipparcos/Tycho-2 system for stars in the 10-16 mag range used as reference stars for the deep CCD imaging data. Here we present final optical position results of 413 sources based on reference stars obtained by dedicated astrograph observations that were reduced following two different procedures. These optical positions are compared to radio very long baseline interferometry positions. The current optical system is not perfectly aligned to the ICRF radio system with rigid body rotation angles of 3-5 mas (= 3σ level) found between them for all three axes. Furthermore, statistically, the optical-radio position differences are found to exceed the total, combined, known errors in the observations. Systematic errors in the optical reference star positions and physical offsets between the centers of optical and radio emissions are both identified as likely causes. A detrimental, astrophysical, random noise component is postulated to be on about the 10 mas level. If confirmed by future observations, this could severely limit the Gaia to ICRF reference frame alignment accuracy to an error of about 0.5 mas per coordinate axis with the current number of sources envisioned to provide the link. A list of 36 ICRF sources without the detection of an optical counterpart to a limiting magnitude of about R = 22 is provided as well.

Low temperature multi-alkali photocathode processing technique for sealed intensified CCD tubes

NASA Technical Reports Server (NTRS)

Doliber, D. L.; Dozier, E. E.; Wenzel, H.; Beaver, E. A.; Hier, R. G.

1989-01-01

A low temperature photocathode process has been used to fabricate an intensified CCD visual photocathode image tube, by incorporating a thinned, backside-illumined CCD as the target anode of a digicon tube of Hubble Space Telescope (HST) design. The CCD digicon tube employs the HST's sodium bialkali photocathode and MgF2 substrate, thereby allowing a direct photocathode quantum efficiency comparison between photocathodes produced by the presently employed low temperature process and those of the conventional high temperature process. Attention is given to the processing chamber used, as well as the details of gas desorption and photocathode processing.

A High Resolution TDI CCD Camera forMicrosatellite (HRCM)

NASA Astrophysics Data System (ADS)

Hao, Yuncai; Zheng, You; Dong, Ying; Li, Tao; Yu, Shijie

In resent years it is a important development direction in the commercial remote sensing field to obtain (1-5)m high ground resolution from space using microsatellite. Thanks to progress of new technologies, new materials and new detectors it is possible to develop 1m ground resolution space imaging system with weight less than 20kg. Based on many years works on optical system design a project of very high resolution TDI CCD camera using in space was proposed by the authors of this paper. The performance parameters and optical lay-out of the HRCM was presented. A compact optical design and results analysis for the system was given in the paper also. and small fold mirror to take a line field of view usable for TDI CCD and short outer size. The length along the largest size direction is about 1/4 of the focal length. And two 4096X96(grades) line TDI CCD will be used as the focal plane detector. The special optical parts are fixed near before the final image for getting the ground pixel resolution higher than the Nyquist resolution of the detector using the sub-pixel technique which will be explained in the paper. In the system optical SiC will be used as the mirror material, the C-C composite material will be used as the material of the mechanical structure framework. The circle frame of the primary and secondary mirrors will use one time turning on a machine tool in order to assuring concentric request for alignment of the system. In general the HRCM have the performance parameters with 2.5m focal length, 20 FOV, 1/11relative aperture, (0.4-0.8) micrometer spectral range, 10 micron pixel size of TDI CCD, weight less than 20kg, 1m ground pixel resolution at flying orbit 500km high. Design and analysis of the HRCM put up in the paper indicate that HRCM have many advantages to use it in space. Keywords High resolution TDI CCD Sub-pixel imaging Light-weighted optical system SiC mirror

pnCCD for photon detection from near-infrared to X-rays

NASA Astrophysics Data System (ADS)

Meidinger, Norbert; Andritschke, Robert; Hartmann, Robert; Herrmann, Sven; Holl, Peter; Lutz, Gerhard; Strüder, Lothar

2006-09-01

A pnCCD is a special type of charge-coupled device developed for spectroscopy and imaging of X-rays with high time resolution and quantum efficiency. Its most famous application is the operation on the XMM-Newton satellite, an X-ray astronomy mission that was launched by the European space agency in 1999. The excellent performance of the focal plane camera has been maintained for more than 6 years in orbit. The energy resolution in particular has shown hardly any degradation since launch. In order to satisfy the requirements of future X-ray astronomy missions as well as those of ground-based experiments, a new type of pnCCD has been developed. This ‘frame-store pnCCD’ shows an enhanced performance compared to the XMM-Newton type of pnCCD. Now, more options in device design and operation are available to tailor the detector to its respective application. Part of this concept is a programmable analog signal processor, which has been developed for the readout of the CCD signals. The electronic noise of the new detector has a value of only 2 electrons equivalent noise charge (ENC), which is less than half of the figure achieved for the XMM-Newton-type pnCCD. The energy resolution for the Mn-Kα line at 5.9 keV is approximately 130 eV FWHM. We have close to 100% quantum efficiency for both low- and high-energy photon detection (e.g. the C-K line at 277 eV, and the Ge-Kα line at 10 keV, respectively). Very high frame rates of 1000 images/s have been achieved due to the ultra-fast readout accomplished by the parallel architecture of the pnCCD and the analog signal processor. Excellent spectroscopic performance is shown even at the relatively high operating temperature of -25 °C that can be achieved by a Peltier cooler. The applications of the low-noise and fast pnCCD detector are not limited to the detection of X-rays. With an anti-reflective coating deposited on the photon entrance window, we achieve high quantum efficiency also for near-infrared and optical

A method of immediate detection of objects with a near-zero apparent motion in series of CCD-frames

NASA Astrophysics Data System (ADS)

Savanevych, V. E.; Khlamov, S. V.; Vavilova, I. B.; Briukhovetskyi, A. B.; Pohorelov, A. V.; Mkrtichian, D. E.; Kudak, V. I.; Pakuliak, L. K.; Dikov, E. N.; Melnik, R. G.; Vlasenko, V. P.; Reichart, D. E.

2018-01-01

The paper deals with a computational method for detection of the solar system minor bodies (SSOs), whose inter-frame shifts in series of CCD-frames during the observation are commensurate with the errors in measuring their positions. These objects have velocities of apparent motion between CCD-frames not exceeding three rms errors (3σ) of measurements of their positions. About 15% of objects have a near-zero apparent motion in CCD-frames, including the objects beyond the Jupiter's orbit as well as the asteroids heading straight to the Earth. The proposed method for detection of the object's near-zero apparent motion in series of CCD-frames is based on the Fisher f-criterion instead of using the traditional decision rules that are based on the maximum likelihood criterion. We analyzed the quality indicators of detection of the object's near-zero apparent motion applying statistical and in situ modeling techniques in terms of the conditional probability of the true detection of objects with a near-zero apparent motion. The efficiency of method being implemented as a plugin for the Collection Light Technology (CoLiTec) software for automated asteroids and comets detection has been demonstrated. Among the objects discovered with this plugin, there was the sungrazing comet C/2012 S1 (ISON). Within 26 min of the observation, the comet's image has been moved by three pixels in a series of four CCD-frames (the velocity of its apparent motion at the moment of discovery was equal to 0.8 pixels per CCD-frame; the image size on the frame was about five pixels). Next verification in observations of asteroids with a near-zero apparent motion conducted with small telescopes has confirmed an efficiency of the method even in bad conditions (strong backlight from the full Moon). So, we recommend applying the proposed method for series of observations with four or more frames.

A compact CCD-monitored atomic force microscope with optical vision and improved performances.

PubMed

Mingyue, Liu; Haijun, Zhang; Dongxian, Zhang

2013-09-01

A novel CCD-monitored atomic force microscope (AFM) with optical vision and improved performances has been developed. Compact optical paths are specifically devised for both tip-sample microscopic monitoring and cantilever's deflection detecting with minimized volume and optimal light-amplifying ratio. The ingeniously designed AFM probe with such optical paths enables quick and safe tip-sample approaching, convenient and effective tip-sample positioning, and high quality image scanning. An image stitching method is also developed to build a wider-range AFM image under monitoring. Experiments show that this AFM system can offer real-time optical vision for tip-sample monitoring with wide visual field and/or high lateral optical resolution by simply switching the objective; meanwhile, it has the elegant performances of nanometer resolution, high stability, and high scan speed. Furthermore, it is capable of conducting wider-range image measurement while keeping nanometer resolution. Copyright © 2013 Wiley Periodicals, Inc.

Flat Field Anomalies in an X-ray CCD Camera Measured Using a Manson X-ray Source

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

M. J. Haugh and M. B. Schneider

2008-10-31

The Static X-ray Imager (SXI) is a diagnostic used at the National Ignition Facility (NIF) to measure the position of the X-rays produced by lasers hitting a gold foil target. The intensity distribution taken by the SXI camera during a NIF shot is used to determine how accurately NIF can aim laser beams. This is critical to proper NIF operation. Imagers are located at the top and the bottom of the NIF target chamber. The CCD chip is an X-ray sensitive silicon sensor, with a large format array (2k x 2k), 24 μm square pixels, and 15 μm thick. Amore » multi-anode Manson X-ray source, operating up to 10kV and 10W, was used to characterize and calibrate the imagers. The output beam is heavily filtered to narrow the spectral beam width, giving a typical resolution E/ΔE≈10. The X-ray beam intensity was measured using an absolute photodiode that has accuracy better than 1% up to the Si K edge and better than 5% at higher energies. The X-ray beam provides full CCD illumination and is flat, within ±1% maximum to minimum. The spectral efficiency was measured at 10 energy bands ranging from 930 eV to 8470 eV. We observed an energy dependent pixel sensitivity variation that showed continuous change over a large portion of the CCD. The maximum sensitivity variation occurred at 8470 eV. The geometric pattern did not change at lower energies, but the maximum contrast decreased and was not observable below 4 keV. We were also able to observe debris, damage, and surface defects on the CCD chip. The Manson source is a powerful tool for characterizing the imaging errors of an X-ray CCD imager. These errors are quite different from those found in a visible CCD imager.« less

Design principles and applications of a cooled CCD camera for electron microscopy.

PubMed

Faruqi, A R

1998-01-01

Cooled CCD cameras offer a number of advantages in recording electron microscope images with CCDs rather than film which include: immediate availability of the image in a digital format suitable for further computer processing, high dynamic range, excellent linearity and a high detective quantum efficiency for recording electrons. In one important respect however, film has superior properties: the spatial resolution of CCD detectors tested so far (in terms of point spread function or modulation transfer function) are inferior to film and a great deal of our effort has been spent in designing detectors with improved spatial resolution. Various instrumental contributions to spatial resolution have been analysed and in this paper we discuss the contribution of the phosphor-fibre optics system in this measurement. We have evaluated the performance of a number of detector components and parameters, e.g. different phosphors (and a scintillator), optical coupling with lens or fibre optics with various demagnification factors, to improve the detector performance. The camera described in this paper, which is based on this analysis, uses a tapered fibre optics coupling between the phosphor and the CCD and is installed on a Philips CM12 electron microscope equipped to perform cryo-microscopy. The main use of the camera so far has been in recording electron diffraction patterns from two dimensional crystals of bacteriorhodopsin--from wild type and from different trapped states during the photocycle. As one example of the type of data obtained with the CCD camera a two dimensional Fourier projection map from the trapped O-state is also included. With faster computers, it will soon be possible to undertake this type of work on an on-line basis. Also, with improvements in detector size and resolution, CCD detectors, already ideal for diffraction, will be able to compete with film in the recording of high resolution images.

Radio-optical reference frame link using the U.S. Naval observatory astrograph and deep CCD imaging

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

Zacharias, N.; Zacharias, M. I., E-mail: nz@usno.navy.mil

2014-05-01

Between 1997 and 2004 several observing runs were conducted, mainly with the CTIO 0.9 m, to image International Celestial Reference Frame (ICRF) counterparts (mostly QSOs) in order to determine accurate optical positions. Contemporary to these deep CCD images, the same fields were observed with the U.S. Naval Observatory astrograph in the same bandpass. They provide accurate positions on the Hipparcos/Tycho-2 system for stars in the 10-16 mag range used as reference stars for the deep CCD imaging data. Here we present final optical position results of 413 sources based on reference stars obtained by dedicated astrograph observations that were reducedmore » following two different procedures. These optical positions are compared to radio very long baseline interferometry positions. The current optical system is not perfectly aligned to the ICRF radio system with rigid body rotation angles of 3-5 mas (= 3σ level) found between them for all three axes. Furthermore, statistically, the optical-radio position differences are found to exceed the total, combined, known errors in the observations. Systematic errors in the optical reference star positions and physical offsets between the centers of optical and radio emissions are both identified as likely causes. A detrimental, astrophysical, random noise component is postulated to be on about the 10 mas level. If confirmed by future observations, this could severely limit the Gaia to ICRF reference frame alignment accuracy to an error of about 0.5 mas per coordinate axis with the current number of sources envisioned to provide the link. A list of 36 ICRF sources without the detection of an optical counterpart to a limiting magnitude of about R = 22 is provided as well.« less

Single-Electron and Single-Photon Sensitivity with a Silicon Skipper CCD

NASA Astrophysics Data System (ADS)

Tiffenberg, Javier; Sofo-Haro, Miguel; Drlica-Wagner, Alex; Essig, Rouven; Guardincerri, Yann; Holland, Steve; Volansky, Tomer; Yu, Tien-Tien

2017-09-01

We have developed ultralow-noise electronics in combination with repetitive, nondestructive readout of a thick, fully depleted charge-coupled device (CCD) to achieve an unprecedented noise level of 0.068 e- rms /pixel . This is the first time that discrete subelectron readout noise has been achieved reproducible over millions of pixels on a stable, large-area detector. This enables the contemporaneous, discrete, and quantized measurement of charge in pixels, irrespective of whether they contain zero electrons or thousands of electrons. Thus, the resulting CCD detector is an ultra-sensitive calorimeter. It is also capable of counting single photons in the optical and near-infrared regime. Implementing this innovative non-destructive readout system has a negligible impact on CCD design and fabrication, and there are nearly immediate scientific applications. As a particle detector, this CCD will have unprecedented sensitivity to low-mass dark matter particles and coherent neutrino-nucleus scattering, while future astronomical applications may include direct imaging and spectroscopy of exoplanets.

Single-Electron and Single-Photon Sensitivity with a Silicon Skipper CCD.

PubMed

Tiffenberg, Javier; Sofo-Haro, Miguel; Drlica-Wagner, Alex; Essig, Rouven; Guardincerri, Yann; Holland, Steve; Volansky, Tomer; Yu, Tien-Tien

2017-09-29

We have developed ultralow-noise electronics in combination with repetitive, nondestructive readout of a thick, fully depleted charge-coupled device (CCD) to achieve an unprecedented noise level of 0.068  e^{-} rms/pixel. This is the first time that discrete subelectron readout noise has been achieved reproducible over millions of pixels on a stable, large-area detector. This enables the contemporaneous, discrete, and quantized measurement of charge in pixels, irrespective of whether they contain zero electrons or thousands of electrons. Thus, the resulting CCD detector is an ultra-sensitive calorimeter. It is also capable of counting single photons in the optical and near-infrared regime. Implementing this innovative non-destructive readout system has a negligible impact on CCD design and fabrication, and there are nearly immediate scientific applications. As a particle detector, this CCD will have unprecedented sensitivity to low-mass dark matter particles and coherent neutrino-nucleus scattering, while future astronomical applications may include direct imaging and spectroscopy of exoplanets.

CCD high-speed videography system with new concepts and techniques

NASA Astrophysics Data System (ADS)

Zheng, Zengrong; Zhao, Wenyi; Wu, Zhiqiang

1997-05-01

A novel CCD high speed videography system with brand-new concepts and techniques is developed by Zhejiang University recently. The system can send a series of short flash pulses to the moving object. All of the parameters, such as flash numbers, flash durations, flash intervals, flash intensities and flash colors, can be controlled according to needs by the computer. A series of moving object images frozen by flash pulses, carried information of moving object, are recorded by a CCD video camera, and result images are sent to a computer to be frozen, recognized and processed with special hardware and software. Obtained parameters can be displayed, output as remote controlling signals or written into CD. The highest videography frequency is 30,000 images per second. The shortest image freezing time is several microseconds. The system has been applied to wide fields of energy, chemistry, medicine, biological engineering, aero- dynamics, explosion, multi-phase flow, mechanics, vibration, athletic training, weapon development and national defense engineering. It can also be used in production streamline to carry out the online, real-time monitoring and controlling.

Digital photography for the light microscope: results with a gated, video-rate CCD camera and NIH-image software.

PubMed

Shaw, S L; Salmon, E D; Quatrano, R S

1995-12-01

In this report, we describe a relatively inexpensive method for acquiring, storing and processing light microscope images that combines the advantages of video technology with the powerful medium now termed digital photography. Digital photography refers to the recording of images as digital files that are stored, manipulated and displayed using a computer. This report details the use of a gated video-rate charge-coupled device (CCD) camera and a frame grabber board for capturing 256 gray-level digital images from the light microscope. This camera gives high-resolution bright-field, phase contrast and differential interference contrast (DIC) images but, also, with gated on-chip integration, has the capability to record low-light level fluorescent images. The basic components of the digital photography system are described, and examples are presented of fluorescence and bright-field micrographs. Digital processing of images to remove noise, to enhance contrast and to prepare figures for printing is discussed.

Infrared imaging spectrometry by the use of bundled chalcogenide glass fibers and a PtSi CCD camera

NASA Astrophysics Data System (ADS)

Saito, Mitsunori; Kikuchi, Katsuhiro; Tanaka, Chinari; Sone, Hiroshi; Morimoto, Shozo; Yamashita, Toshiharu T.; Nishii, Junji

1999-10-01

A coherent fiber bundle for infrared image transmission was prepared by arranging 8400 chalcogenide (AsS) glass fibers. The fiber bundle, 1 m in length, is transmissive in the infrared spectral region of 1 - 6 micrometer. A remote spectroscopic imaging system was constructed with the fiber bundle and an infrared PtSi CCD camera. The system was used for the real-time observation (frame time: 1/60 s) of gas distribution. Infrared light from a SiC heater was delivered to a gas cell through a chalcogenide fiber, and transmitted light was observed through the fiber bundle. A band-pass filter was used for the selection of gas species. A He-Ne laser of 3.4 micrometer wavelength was also used for the observation of hydrocarbon gases. Gases bursting from a nozzle were observed successfully by a remote imaging system.

Imaging the Moon II: Webcam CCD Observations and Analysis (a Two-Week Lab for Non-Majors)

NASA Astrophysics Data System (ADS)

Sato, T.

2014-07-01

Imaging the Moon is a successful two-week lab involving real sky observations of the Moon in which students make telescopic observations and analyze their own images. Originally developed around the 35 mm film camera, a common household object adapted for astronomical work, the lab now uses webcams as film photography has evolved into an obscure specialty technology and increasing numbers of students have little familiarity with it. The printed circuit board with the CCD is harvested from a commercial webcam and affixed to a tube to mount on a telescope in place of an eyepiece. Image frames are compiled to form a lunar mosaic, and crater sizes are measured. Students also work through the logistical steps of telescope time assignment and scheduling. They learn to keep a schedule and work with uncertainties of weather in ways paralleling research observations. Because there is no need for a campus observatory, this lab can be replicated at a wide variety of institutions.

Jig Aligns Shadow Mask On CCD

NASA Technical Reports Server (NTRS)

Matus, Carlos V.

1989-01-01

Alignment viewed through microscope. Alignment jig positions shadow mask on charge-coupled device (CCD) so metal film deposited on it precisely. Allows CCD package to be inserted and removed without disturbing alignment of mask. Holds CCD packages securely and isolates it electrostatically while providing electrical contact to each of its pins. When alignment jig assembled with CCD, used to move mask under micrometer control.

Ultraviolet downconverting phosphor for use with silicon CCD imagers

NASA Technical Reports Server (NTRS)

Blouke, M. M.; Cowens, M. W.; Hall, J. E.; Westphal, J. A.; Christensen, A. B.

1980-01-01

The properties and application of a UV downconverting phosphor (coronene) to silicon charge coupled devices are discussed. Measurements of the absorption spectrum have been extended to below 1000 A, and preliminary results indicate the existence of useful response to at least 584 A. The average conversion efficiency of coronene was measured to be approximately 20% at 2537 A. Imagery at 3650 A using a backside illuminated 800 x 800 CCD coated with coronene is presented.

High-performance visible/UV CCD focal plane technology for spacebased applications

NASA Technical Reports Server (NTRS)

Burke, B. E.; Mountain, R. W.; Gregory, J. A.; Huang, J. C. M.; Cooper, M. J.; Savoye, E. D.; Kosicki, B. B.

1993-01-01

We describe recent technology developments aimed at large CCD imagers for space based applications in the visible and UV. Some of the principal areas of effort include work on reducing device degradation in the natural space-radiation environment, improvements in quantum efficiency in the visible and UV, and larger-device formats. One of the most serious hazards for space based CCD's operating at low signal levels is the displacement damage resulting from bombardment by energetic protons. Such damage degrades charge-transfer efficiency and increases dark current. We have achieved improved hardness to proton-induced displacement damage by selective ion implants into the CCD channel and by reduced temperature of operation. To attain high quantum efficiency across the visible and UV we have developed a technology for back-illuminated CCD's. With suitable antireflection (AR) coatings such devices have quantum efficiencies near 90 percent in the 500-700-nm band. In the UV band from 200 to 400 nm, where it is difficult to find coatings that are sufficiently transparent and can provide good matching to the high refractive index of silicon, we have been able to substantially increase the quantum efficiency using a thin film of HfO2 as an AR coating. These technology efforts were applied to a 420 x 420-pixel frame-transfer imager, and future work will be extended to a 1024 x 1024-pixel device now under development.

Single-Electron and Single-Photon Sensitivity with a Silicon Skipper CCD

DOE PAGES

Tiffenberg, Javier; Sofo-Haro, Miguel; Drlica-Wagner, Alex; ...

2017-09-26

Here, we have developed ultralow-noise electronics in combination with repetitive, nondestructive readout of a thick, fully depleted charge-coupled device (CCD) to achieve an unprecedented noise level of 0.068 e - rms/pixel. This is the first time that discrete subelectron readout noise has been achieved reproducible over millions of pixels on a stable, large-area detector. This enables the contemporaneous, discrete, and quantized measurement of charge in pixels, irrespective of whether they contain zero electrons or thousands of electrons. Thus, the resulting CCD detector is an ultra-sensitive calorimeter. It is also capable of counting single photons in the optical and near-infrared regime.more » Implementing this innovative non-destructive readout system has a negligible impact on CCD design and fabrication, and there are nearly immediate scientific applications. As a particle detector, this CCD will have unprecedented sensitivity to low-mass dark matter particles and coherent neutrino-nucleus scattering, while future astronomical applications may include direct imaging and spectroscopy of exoplanets.« less

Sonnenaufnahmen mit einer Starlight X-Press CCD-Kamera.

NASA Astrophysics Data System (ADS)

Bernhard, K.

1997-03-01

To take-up the sun, most amateurastronomers use the photographic method. In this article the author shows, that CCD is also a suitable method to do this. Especially the possibilities to see immediately the result of focusing on the screen and the electronic processing are very useful to get sharp and high-contrast images of the sun.

The Development of the Spanish Fireball Network Using a New All-Sky CCD System

NASA Astrophysics Data System (ADS)

Trigo-Rodríguez, J. M.; Castro-Tirado, A. J.; Llorca, J.; Fabregat, J.; Martínez, V. J.; Reglero, V.; Jelínek, M.; Kubánek, P.; Mateo, T.; Postigo, A. De Ugarte

2004-12-01

We have developed an all-sky charge coupled devices (CCD) automatic system for detecting meteors and fireballs that will be operative in four stations in Spain during 2005. The cameras were developed following the BOOTES-1 prototype installed at the El Arenosillo Observatory in 2002, which is based on a CCD detector of 4096 × 4096 pixels with a fish-eye lens that provides an all-sky image with enough resolution to make accurate astrometric measurements. Since late 2004, a couple of cameras at two of the four stations operate for 30 s in alternate exposures, allowing 100% time coverage. The stellar limiting magnitude of the images is +10 in the zenith, and +8 below ~ 65° of zenithal angle. As a result, the images provide enough comparison stars to make astrometric measurements of faint meteors and fireballs with an accuracy of ~ 2°arcminutes. Using this prototype, four automatic all-sky CCD stations have been developed, two in Andalusia and two in the Valencian Community, to start full operation of the Spanish Fireball Network. In addition to all-sky coverage, we are developing a fireball spectroscopy program using medium field lenses with additional CCD cameras. Here we present the first images obtained from the El Arenosillo and La Mayora stations in Andalusia during their first months of activity. The detection of the Jan 27, 2003 superbolide of ± 17 ± 1 absolute magnitude that overflew Algeria and Morocco is an example of the detection capability of our prototype.

Ultrahigh-frame CCD imagers

NASA Astrophysics Data System (ADS)

Lowrance, John L.; Mastrocola, V. J.; Renda, George F.; Swain, Pradyumna K.; Kabra, R.; Bhaskaran, Mahalingham; Tower, John R.; Levine, Peter A.

2004-02-01

This paper describes the architecture, process technology, and performance of a family of high burst rate CCDs. These imagers employ high speed, low lag photo-detectors with local storage at each photo-detector to achieve image capture at rates greater than 106 frames per second. One imager has a 64 x 64 pixel array with 12 frames of storage. A second imager has a 80 x 160 array with 28 frames of storage, and the third imager has a 64 x 64 pixel array with 300 frames of storage. Application areas include capture of rapid mechanical motion, optical wavefront sensing, fluid cavitation research, combustion studies, plasma research and wind-tunnel-based gas dynamics research.

Enhanced performance CCD output amplifier

DOEpatents

Dunham, Mark E.; Morley, David W.

1996-01-01

A low-noise FET amplifier is connected to amplify output charge from a che coupled device (CCD). The FET has its gate connected to the CCD in common source configuration for receiving the output charge signal from the CCD and output an intermediate signal at a drain of the FET. An intermediate amplifier is connected to the drain of the FET for receiving the intermediate signal and outputting a low-noise signal functionally related to the output charge signal from the CCD. The amplifier is preferably connected as a virtual ground to the FET drain. The inherent shunt capacitance of the FET is selected to be at least equal to the sum of the remaining capacitances.

Crystallization of the C-terminal domain of the addiction antidote CcdA in complex with its toxin CcdB

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

Buts, Lieven; De Jonge, Natalie; Loris, Remy, E-mail: reloris@vub.ac.be

2005-10-01

The CcdA C-terminal domain was crystallized in complex with CcdB in two crystal forms that diffract to beyond 2.0 Å resolution. CcdA and CcdB are the antidote and toxin of the ccd addiction module of Escherichia coli plasmid F. The CcdA C-terminal domain (CcdA{sub C36}; 36 amino acids) was crystallized in complex with CcdB (dimer of 2 × 101 amino acids) in three different crystal forms, two of which diffract to high resolution. Form II belongs to space group P2{sub 1}2{sub 1}2{sub 1}, with unit-cell parameters a = 37.6, b = 60.5, c = 83.8 Å and diffracts to 1.8more » Å resolution. Form III belongs to space group P2{sub 1}, with unit-cell parameters a = 41.0, b = 37.9, c = 69.6 Å, β = 96.9°, and diffracts to 1.9 Å resolution.« less

Reduction of time-resolved space-based CCD photometry developed for MOST Fabry Imaging data*

NASA Astrophysics Data System (ADS)

Reegen, P.; Kallinger, T.; Frast, D.; Gruberbauer, M.; Huber, D.; Matthews, J. M.; Punz, D.; Schraml, S.; Weiss, W. W.; Kuschnig, R.; Moffat, A. F. J.; Walker, G. A. H.; Guenther, D. B.; Rucinski, S. M.; Sasselov, D.

2006-04-01

The MOST (Microvariability and Oscillations of Stars) satellite obtains ultraprecise photometry from space with high sampling rates and duty cycles. Astronomical photometry or imaging missions in low Earth orbits, like MOST, are especially sensitive to scattered light from Earthshine, and all these missions have a common need to extract target information from voluminous data cubes. They consist of upwards of hundreds of thousands of two-dimensional CCD frames (or subrasters) containing from hundreds to millions of pixels each, where the target information, superposed on background and instrumental effects, is contained only in a subset of pixels (Fabry Images, defocused images, mini-spectra). We describe a novel reduction technique for such data cubes: resolving linear correlations of target and background pixel intensities. This step-wise multiple linear regression removes only those target variations which are also detected in the background. The advantage of regression analysis versus background subtraction is the appropriate scaling, taking into account that the amount of contamination may differ from pixel to pixel. The multivariate solution for all pairs of target/background pixels is minimally invasive of the raw photometry while being very effective in reducing contamination due to, e.g. stray light. The technique is tested and demonstrated with both simulated oscillation signals and real MOST photometry.

Correcting STIS CCD Point-Source Spectra for CTE Loss

NASA Technical Reports Server (NTRS)

Goudfrooij, Paul; Bohlin, Ralph C.; Maiz-Apellaniz, Jesus

2006-01-01

We review the on-orbit spectroscopic observations that are being used to characterize the Charge Transfer Efficiency (CTE) of the STIS CCD in spectroscopic mode. We parameterize the CTE-related loss for spectrophotometry of point sources in terms of dependencies on the brightness of the source, the background level, the signal in the PSF outside the standard extraction box, and the time of observation. Primary constraints on our correction algorithm are provided by measurements of the CTE loss rates for simulated spectra (images of a tungsten lamp taken through slits oriented along the dispersion axis) combined with estimates of CTE losses for actual spectra of spectrophotometric standard stars in the first order CCD modes. For point-source spectra at the standard reference position at the CCD center, CTE losses as large as 30% are corrected to within approx.1% RMS after application of the algorithm presented here, rendering the Poisson noise associated with the source detection itself to be the dominant contributor to the total flux calibration uncertainty.

Transmission electron microscope CCD camera

DOEpatents

Downing, Kenneth H.

1999-01-01

In order to improve the performance of a CCD camera on a high voltage electron microscope, an electron decelerator is inserted between the microscope column and the CCD. This arrangement optimizes the interaction of the electron beam with the scintillator of the CCD camera while retaining optimization of the microscope optics and of the interaction of the beam with the specimen. Changing the electron beam energy between the specimen and camera allows both to be optimized.

Spectroscopy and CCD-photography of extended red emission in reflection nebulae

NASA Technical Reports Server (NTRS)

Witt, A. N.; Schild, R. E.

1986-01-01

Recent spectrographic studies of extended red emission (ERE) seen in the 0.6 to 0.9 micron spectral region in many reflection nebulae have shown fluorescence by amorphous hydrogenated carbon to be the most probable cause of the ERE. Spectrographic observations were performed on the nebulae NGC 2023 and NGC 7023, using the intensified Reticon scanner (IRS) of Kitt Peak National Observatory on the N0-2 0.9 mm telescope. Charge coupled device (CCD) images of NGC2023 and NGC 7023 were obtained with the CfA CCD detector on the 0.6 mm telescope of the Whipple Observatory. Results are discussed.

Characterization of a fully depleted CCD on high-resistivity silicon

NASA Astrophysics Data System (ADS)

Stover, Richard J.; Wei, Mingzhi; Lee, Y.; Gilmore, David K.; Holland, S. E.; Groom, D. E.; Moses, William W.; Perlmutter, Saul; Goldhaber, G.; Pennypacker, C.; Wang, N. W.; Palaio, N.

1997-04-01

Most scientific CCD imagers are fabricated on 30-50 (Omega) - cm epitaxial silicon. When illuminated form the front side of the device they generally have low quantum efficiency in the blue region of the visible spectrum because of strong absorption in the polycrystalline silicon gates as well as poor quantum efficiency in the far red and near infrared region of the spectrum because of the shallow depletion depth of the low-resistivity silicon. To enhance the blue response of scientific CCDs they are often thinned and illuminated from the back side. While blue response is greatly enhanced by this process, it is expensive and it introduces additional problems for the red end of the spectrum. A typical thinned CCD is 15 to 25 micrometers thick, and at wavelengths beyond about 800 nm the absorption depth becomes comparable to the thickness of the device, leading to interference fringes from reflected light. Because these interference fringes are of high order, the spatial pattern of the fringes is extremely sensitive to small changes in the optical illumination of the detector. Calibration and removal of the effects of the fringes is one of the primary limitations on the performance of astronomical images taken at wavelengths of 800 nm or more. In this paper we present results from the characterization of a CCD which promises to address many of the problems of typical thinned CCDs. The CCD reported on here was fabricated at Lawrence Berkeley National Laboratory (LBNL) on a 10-12 K$OMega-cm n-type silicon substrate.THe CCD is a 200 by 200 15-micrometers square pixel array, and due to the very high resistivity of the starting material, the entire 300 micrometers substrate is depleted. Full depletion works because of the gettering technology developed at LBNL which keeps leakage current down. Both front-side illuminated and backside illuminated devices have been tested. We have measured quantum efficiency, read-noise, full-well, charge-transfer efficiency, and leakage

Measuring high-resolution sky luminance distributions with a CCD camera.

PubMed

Tohsing, Korntip; Schrempf, Michael; Riechelmann, Stefan; Schilke, Holger; Seckmeyer, Gunther

2013-03-10

We describe how sky luminance can be derived from a newly developed hemispherical sky imager (HSI) system. The system contains a commercial compact charge coupled device (CCD) camera equipped with a fish-eye lens. The projection of the camera system has been found to be nearly equidistant. The luminance from the high dynamic range images has been calculated and then validated with luminance data measured by a CCD array spectroradiometer. The deviation between both datasets is less than 10% for cloudless and completely overcast skies, and differs by no more than 20% for all sky conditions. The global illuminance derived from the HSI pictures deviates by less than 5% and 20% under cloudless and cloudy skies for solar zenith angles less than 80°, respectively. This system is therefore capable of measuring sky luminance with the high spatial and temporal resolution of more than a million pixels and every 20 s respectively.

A method of rapidly evaluating image quality of NED optical system

NASA Astrophysics Data System (ADS)

Sun, Qi; Qiu, Chuankai; Yang, Huan

2014-11-01

In recent years, with the development of technology of micro-display, advanced optics and the software and hardware, near-to-eye display ( NED) optical system will have a wide range of potential applications in the fields of amusement and virtual reality. However, research on the evaluating image quality of this kind optical system is comparatively lagging behind. Although now there are some methods and equipment for evaluation, they can't be applied in commercial production because of their complex operation and inaccuracy. In this paper, an academic method is proposed and a Rapid Evaluation System (RES) is designed to evaluate the image of optical system rapidly and exactly. Firstly, a set of parameters that eyes are sensitive to and also express the quality of system should be extracted and quantized to be criterion, so the evaluation standards can be established. Then, some parameters can be detected by RES consisted of micro-display, CCD camera and computer and so on. By process of scaling, the measuring results of the RES are exact and creditable, relationship between object measurement, subjective evaluation and the RES will be established. After that, image quality of optical system can be evaluated just by detecting parameters of that. The RES is simple and the results of evaluation are exact and keeping with human vision. So the method can be used not only for optimizing design of optical system, but also for evaluation in commercial production.

CCD centroiding experiment for JASMINE and ILOM

NASA Astrophysics Data System (ADS)

Yano, Taihei; Araki, Hiroshi; Gouda, Naoteru; Kobayashi, Yukiyasu; Tsujimoto, Takuji; Nakajima, Tadashi; Kawano, Nobuyuki; Tazawa, Seiichi; Yamada, Yoshiyuki; Hanada, Hideo; Asari, Kazuyoshi; Tsuruta, Seiitsu

2006-06-01

JASMINE and ILOM are space missions which are in progress at the National Astronomical Observatory of Japan. These two projects need a common astrometric technique to obtain precise positions of star images on solid state detectors to accomplish the objectives. We have carried out measurements of centroid of artificial star images on a CCD to investigate the accuracy of the positions of the stars, using an algorithm for estimating them from photon weighted means of the stars. We find that the accuracy of the star positions reaches 1/300 pixel for one measurement. We also measure positions of stars, using an algorithm for correcting the distorted optical image. Finally, we find that the accuracy of the measurement for the positions of the stars from the strongly distorted image is under 1/150 pixel for one measurement.

High-performance dual-speed CCD camera system for scientific imaging

NASA Astrophysics Data System (ADS)

Simpson, Raymond W.

1996-03-01

Traditionally, scientific camera systems were partitioned with a `camera head' containing the CCD and its support circuitry and a camera controller, which provided analog to digital conversion, timing, control, computer interfacing, and power. A new, unitized high performance scientific CCD camera with dual speed readout at 1 X 106 or 5 X 106 pixels per second, 12 bit digital gray scale, high performance thermoelectric cooling, and built in composite video output is described. This camera provides all digital, analog, and cooling functions in a single compact unit. The new system incorporates the A/C converter, timing, control and computer interfacing in the camera, with the power supply remaining a separate remote unit. A 100 Mbyte/second serial link transfers data over copper or fiber media to a variety of host computers, including Sun, SGI, SCSI, PCI, EISA, and Apple Macintosh. Having all the digital and analog functions in the camera made it possible to modify this system for the Woods Hole Oceanographic Institution for use on a remote controlled submersible vehicle. The oceanographic version achieves 16 bit dynamic range at 1.5 X 105 pixels/second, can be operated at depths of 3 kilometers, and transfers data to the surface via a real time fiber optic link.

PN-CCD camera for XMM: performance of high time resolution/bright source operating modes

NASA Astrophysics Data System (ADS)

Kendziorra, Eckhard; Bihler, Edgar; Grubmiller, Willy; Kretschmar, Baerbel; Kuster, Markus; Pflueger, Bernhard; Staubert, Ruediger; Braeuninger, Heinrich W.; Briel, Ulrich G.; Meidinger, Norbert; Pfeffermann, Elmar; Reppin, Claus; Stoetter, Diana; Strueder, Lothar; Holl, Peter; Kemmer, Josef; Soltau, Heike; von Zanthier, Christoph

1997-10-01

The pn-CCD camera is developed as one of the focal plane instruments for the European photon imaging camera (EPIC) on board the x-ray multi mirror (XMM) mission to be launched in 1999. The detector consists of four quadrants of three pn-CCDs each, which are integrated on one silicon wafer. Each CCD has 200 by 64 pixels (150 micrometer by 150 micrometers) with 280 micrometers depletion depth. One CCD of a quadrant is read out at a time, while the four quadrants can be processed independently of each other. In standard imaging mode the CCDs are read out sequentially every 70 ms. Observations of point sources brighter than 1 mCrab will be effected by photon pile- up. However, special operating modes can be used to observe bright sources up to 150 mCrab in timing mode with 30 microseconds time resolution and very bright sources up to several crab in burst mode with 7 microseconds time resolution. We have tested one quadrant of the EPIC pn-CCD camera at line energies from 0.52 keV to 17.4 keV at the long beam test facility Panter in the focus of the qualification mirror module for XMM. In order to test the time resolution of the system, a mechanical chopper was used to periodically modulate the beam intensity. Pulse periods down to 0.7 ms were generated. This paper describes the performance of the pn-CCD detector in timing and burst readout modes with special emphasis on energy and time resolution.

SU-E-T-161: SOBP Beam Analysis Using Light Output of Scintillation Plate Acquired by CCD Camera.

PubMed

Cho, S; Lee, S; Shin, J; Min, B; Chung, K; Shin, D; Lim, Y; Park, S

2012-06-01

To analyze Bragg-peak beams in SOBP (spread-out Bragg-peak) beam using CCD (charge-coupled device) camera - scintillation screen system. We separated each Bragg-peak beam using light output of high sensitivity scintillation material acquired by CCD camera and compared with Bragg-peak beams calculated by Monte Carlo simulation. In this study, CCD camera - scintillation screen system was constructed with a high sensitivity scintillation plate (Gd2O2S:Tb) and a right-angled prismatic PMMA phantom, and a Marlin F-201B, EEE-1394 CCD camera. SOBP beam irradiated by the double scattering mode of a PROTEUS 235 proton therapy machine in NCC is 8 cm width, 13 g/cm 2 range. The gain, dose rate and current of this beam is 50, 2 Gy/min and 70 nA, respectively. Also, we simulated the light output of scintillation plate for SOBP beam using Geant4 toolkit. We evaluated the light output of high sensitivity scintillation plate according to intergration time (0.1 - 1.0 sec). The images of CCD camera during the shortest intergration time (0.1 sec) were acquired automatically and randomly, respectively. Bragg-peak beams in SOBP beam were analyzed by the acquired images. Then, the SOBP beam used in this study was calculated by Geant4 toolkit and Bragg-peak beams in SOBP beam were obtained by ROOT program. The SOBP beam consists of 13 Bragg-peak beams. The results of experiment were compared with that of simulation. We analyzed Bragg-peak beams in SOBP beam using light output of scintillation plate acquired by CCD camera and compared with that of Geant4 simulation. We are going to study SOBP beam analysis using more effective the image acquisition technique. © 2012 American Association of Physicists in Medicine.

Nano-JASMINE: cosmic radiation degradation of CCD performance and centroid detection

NASA Astrophysics Data System (ADS)

Kobayashi, Yukiyasu; Shimura, Yuki; Niwa, Yoshito; Yano, Taihei; Gouda, Naoteru; Yamada, Yoshiyuki

2012-09-01

Nano-JASMINE (NJ) is a very small astrometry satellite project led by the National Astronomical Observatory of Japan. The satellite is ready for launch, and the launch is currently scheduled for late 2013 or early 2014. The satellite is equipped with a fully depleted CCD and is expected to perform astrometry observations for stars brighter than 9 mag in the zw-band (0.6 µm-1.0 µm). Distances of stars located within 100 pc of the Sun can be determined by using annual parallax measurements. The targeted accuracy for the position determination of stars brighter than 7.5 mag is 3 mas, which is equivalent to measuring the positions of stars with an accuracy of less than one five-hundredth of the CCD pixel size. The position measurements of stars are performed by centroiding the stellar images taken by the CCD that operates in the time and delay integration mode. The degradation of charge transfer performance due to cosmic radiation damage in orbit is proved experimentally. A method is then required to compensate for the effects of performance degradation. One of the most effective ways of achieving this is to simulate observed stellar outputs, including the effect of CCD degradation, and then formulate our centroiding algorithm and evaluate the accuracies of the measurements. We report here the planned procedure to simulate the outputs of the NJ observations. We also developed a CCD performance-measuring system and present preliminary results obtained using the system.

Analysis of Dark Current in BRITE Nanostellite CCD Sensors †

PubMed Central

Popowicz, Adam

2018-01-01

The BRightest Target Explorer (BRITE) is the pioneering nanosatellite mission dedicated for photometric observations of the brightest stars in the sky. The BRITE charge coupled device (CCD) sensors are poorly shielded against extensive flux of energetic particles which constantly induce defects in the silicon lattice. In this paper we investigate the temporal evolution of the generation of the dark current in the BRITE CCDs over almost four years after launch. Utilizing several steps of image processing and employing normalization of the results, it was possible to obtain useful information about the progress of thermal activity in the sensors. The outcomes show a clear and consistent linear increase of induced damage despite the fact that only about 0.14% of CCD pixels were probed. By performing the analysis of temperature dependencies of the dark current, we identified the observed defects as phosphorus-vacancy (PV) pairs, which are common in proton irradiated CCD matrices. Moreover, the Meyer-Neldel empirical rule was confirmed in our dark current data, yielding EMN=24.8 meV for proton-induced PV defects. PMID:29415471

Systems approach to the design of the CCD sensors and camera electronics for the AIA and HMI instruments on solar dynamics observatory

NASA Astrophysics Data System (ADS)

Waltham, N.; Beardsley, S.; Clapp, M.; Lang, J.; Jerram, P.; Pool, P.; Auker, G.; Morris, D.; Duncan, D.

2017-11-01

Solar Dynamics Observatory (SDO) is imaging the Sun in many wavelengths near simultaneously and with a resolution ten times higher than the average high-definition television. In this paper we describe our innovative systems approach to the design of the CCD cameras for two of SDO's remote sensing instruments, the Atmospheric Imaging Assembly (AIA) and the Helioseismic and Magnetic Imager (HMI). Both instruments share use of a custom-designed 16 million pixel science-grade CCD and common camera readout electronics. A prime requirement was for the CCD to operate with significantly lower drive voltages than before, motivated by our wish to simplify the design of the camera readout electronics. Here, the challenge lies in the design of circuitry to drive the CCD's highly capacitive electrodes and to digitize its analogue video output signal with low noise and to high precision. The challenge is greatly exacerbated when forced to work with only fully space-qualified, radiation-tolerant components. We describe our systems approach to the design of the AIA and HMI CCD and camera electronics, and the engineering solutions that enabled us to comply with both mission and instrument science requirements.

Chromatic Modulator for High Resolution CCD or APS Devices

NASA Technical Reports Server (NTRS)

Hartley, Frank T. (Inventor); Hull, Anthony B. (Inventor)

2003-01-01

A system for providing high-resolution color separation in electronic imaging. Comb drives controllably oscillate a red-green-blue (RGB) color strip filter system (or otherwise) over an electronic imaging system such as a charge-coupled device (CCD) or active pixel sensor (APS). The color filter is modulated over the imaging array at a rate three or more times the frame rate of the imaging array. In so doing, the underlying active imaging elements are then able to detect separate color-separated images, which are then combined to provide a color-accurate frame which is then recorded as the representation of the recorded image. High pixel resolution is maintained. Registration is obtained between the color strip filter and the underlying imaging array through the use of electrostatic comb drives in conjunction with a spring suspension system.

Optical synthesizer for a large quadrant-array CCD camera: Center director's discretionary fund

NASA Technical Reports Server (NTRS)

Hagyard, Mona J.

1992-01-01

The objective of this program was to design and develop an optical device, an optical synthesizer, that focuses four contiguous quadrants of a solar image on four spatially separated CCD arrays that are part of a unique CCD camera system. This camera and the optical synthesizer will be part of the new NASA-Marshall Experimental Vector Magnetograph, and instrument developed to measure the Sun's magnetic field as accurately as present technology allows. The tasks undertaken in the program are outlined and the final detailed optical design is presented.

An LOD with improved breakdown voltage in full-frame CCD devices

NASA Astrophysics Data System (ADS)

Banghart, Edmund K.; Stevens, Eric G.; Doan, Hung Q.; Shepherd, John P.; Meisenzahl, Eric J.

2005-02-01

In full-frame image sensors, lateral overflow drain (LOD) structures are typically formed along the vertical CCD shift registers to provide a means for preventing charge blooming in the imager pixels. In a conventional LOD structure, the n-type LOD implant is made through the thin gate dielectric stack in the device active area and adjacent to the thick field oxidation that isolates the vertical CCD columns of the imager. In this paper, a novel LOD structure is described in which the n-type LOD impurities are placed directly under the field oxidation and are, therefore, electrically isolated from the gate electrodes. By reducing the electrical fields that cause breakdown at the silicon surface, this new structure permits a larger amount of n-type impurities to be implanted for the purpose of increasing the LOD conductivity. As a consequence of the improved conductance, the LOD width can be significantly reduced, enabling the design of higher resolution imaging arrays without sacrificing charge capacity in the pixels. Numerical simulations with MEDICI of the LOD leakage current are presented that identify the breakdown mechanism, while three-dimensional solutions to Poisson's equation are used to determine the charge capacity as a function of pixel dimension.

CCD Photometry of bright stars using objective wire mesh

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

Kamiński, Krzysztof; Zgórz, Marika; Schwarzenberg-Czerny, Aleksander, E-mail: chrisk@amu.edu.pl

2014-06-01

Obtaining accurate photometry of bright stars from the ground remains problematic due to the danger of overexposing the target and/or the lack of suitable nearby comparison stars. The century-old method of using objective wire mesh to produce multiple stellar images seems promising for the precise CCD photometry of such stars. Furthermore, our tests on β Cep and its comparison star, differing by 5 mag, are very encouraging. Using a CCD camera and a 20 cm telescope with the objective covered by a plastic wire mesh, in poor weather conditions, we obtained differential photometry with a precision of 4.5 mmag permore » two minute exposure. Our technique is flexible and may be tuned to cover a range as big as 6-8 mag. We discuss the possibility of installing a wire mesh directly in the filter wheel.« less

A fast double shutter for CCD-based metrology

NASA Astrophysics Data System (ADS)

Geisler, R.

2017-02-01

Image based metrology such as Particle Image Velocimetry (PIV) depends on the comparison of two images of an object taken in fast succession. Cameras for these applications provide the so-called `double shutter' mode: One frame is captured with a short exposure time and in direct succession a second frame with a long exposure time can be recorded. The difference in the exposure times is typically no problem since illumination is provided by a pulsed light source such as a laser and the measurements are performed in a darkened environment to prevent ambient light from accumulating in the long second exposure time. However, measurements of self-luminous processes (e.g. plasma, combustion ...) as well as experiments in ambient light are difficult to perform and require special equipment (external shutters, highspeed image sensors, multi-sensor systems ...). Unfortunately, all these methods incorporate different drawbacks such as reduced resolution, degraded image quality, decreased light sensitivity or increased susceptibility to decalibration. In the solution presented here, off-the-shelf CCD sensors are used with a special timing to combine neighbouring pixels in a binning-like way. As a result, two frames of short exposure time can be captured in fast succession. They are stored in the on-chip vertical register in a line-interleaved pattern, read out in the common way and separated again by software. The two resultant frames are completely congruent; they expose no insensitive lines or line shifts and thus enable sub-pixel accurate measurements. A third frame can be captured at the full resolution analogue to the double shutter technique. Image based measurement techniques such as PIV can benefit from this mode when applied in bright environments. The third frame is useful e.g. for acceleration measurements or for particle tracking applications.

Improved Line Tracing Methods for Removal of Bad Streaks Noise in CCD Line Array Image—A Case Study with GF-1 Images

PubMed Central

Wang, Bo; Bao, Jianwei; Wang, Shikui; Wang, Houjun; Sheng, Qinghong

2017-01-01

Remote sensing images could provide us with tremendous quantities of large-scale information. Noise artifacts (stripes), however, made the images inappropriate for vitalization and batch process. An effective restoration method would make images ready for further analysis. In this paper, a new method is proposed to correct the stripes and bad abnormal pixels in charge-coupled device (CCD) linear array images. The method involved a line tracing method, limiting the location of noise to a rectangular region, and corrected abnormal pixels with the Lagrange polynomial algorithm. The proposed detection and restoration method were applied to Gaofen-1 satellite (GF-1) images, and the performance of this method was evaluated by omission ratio and false detection ratio, which reached 0.6% and 0%, respectively. This method saved 55.9% of the time, compared with traditional method. PMID:28441754

New low noise CCD cameras for Pi-of-the-Sky project

NASA Astrophysics Data System (ADS)

Kasprowicz, G.; Czyrkowski, H.; Dabrowski, R.; Dominik, W.; Mankiewicz, L.; Pozniak, K.; Romaniuk, R.; Sitek, P.; Sokolowski, M.; Sulej, R.; Uzycki, J.; Wrochna, G.

2006-10-01

Modern research trends require observation of fainter and fainter astronomical objects on large areas of the sky. This implies usage of systems with high temporal and optical resolution with computer based data acquisition and processing. Therefore Charge Coupled Devices (CCD) became so popular. They offer quick picture conversion with much better quality than film based technologies. This work is theoretical and practical study of the CCD based picture acquisition system. The system was optimized for "Pi of The Sky" project. But it can be adapted to another professional astronomical researches. The work includes issue of picture conversion, signal acquisition, data transfer and mechanical construction of the device.

Image quality evaluation of medical color and monochrome displays using an imaging colorimeter

NASA Astrophysics Data System (ADS)

Roehrig, Hans; Gu, Xiliang; Fan, Jiahua

2012-10-01

The purpose of this presentation is to demonstrate the means which permit examining the accuracy of Image Quality with respect to MTF (Modulation Transfer Function) and NPS (Noise Power Spectrum) of Color Displays and Monochrome Displays. Indications were in the past that color displays could affect the clinical performance of color displays negatively compared to monochrome displays. Now colorimeters like the PM-1423 are available which have higher sensitivity and color accuracy than the traditional cameras like CCD cameras. Reference (1) was not based on measurements made with a colorimeter. This paper focuses on the measurements of physical characteristics of the spatial resolution and noise performance of color and monochrome medical displays which were made with a colorimeter and we will after this meeting submit the data to an ROC study so we have again a paper to present at a future SPIE Conference.Specifically, Modulation Transfer Function (MTF) and Noise Power Spectrum (NPS) were evaluated and compared at different digital driving levels (DDL) between the two medical displays. This paper focuses on the measurements of physical characteristics of the spatial resolution and noise performance of color and monochrome medical displays which were made with a colorimeter and we will after this meeting submit the data to an ROC study so we have again a paper to present at a future Annual SPIE Conference. Specifically, Modulation Transfer Function (MTF) and Noise Power Spectrum (NPS) were evaluated and compared at different digital driving levels (DDL) between the two medical displays. The Imaging Colorimeter. Measurement of color image quality needs were done with an imaging colorimeter as it is shown below. Imaging colorimetry is ideally suited to FPD measurement because imaging systems capture spatial data generating millions of data points in a single measurement operation. The imaging colorimeter which was used was the PM-1423 from Radiant Imaging. It uses

Testing fully depleted CCD

NASA Astrophysics Data System (ADS)

Casas, Ricard; Cardiel-Sas, Laia; Castander, Francisco J.; Jiménez, Jorge; de Vicente, Juan

2014-08-01

The focal plane of the PAU camera is composed of eighteen 2K x 4K CCDs. These devices, plus four spares, were provided by the Japanese company Hamamatsu Photonics K.K. with type no. S10892-04(X). These detectors are 200 μm thick fully depleted and back illuminated with an n-type silicon base. They have been built with a specific coating to be sensitive in the range from 300 to 1,100 nm. Their square pixel size is 15 μm. The read-out system consists of a Monsoon controller (NOAO) and the panVIEW software package. The deafualt CCD read-out speed is 133 kpixel/s. This is the value used in the calibration process. Before installing these devices in the camera focal plane, they were characterized using the facilities of the ICE (CSIC- IEEC) and IFAE in the UAB Campus in Bellaterra (Barcelona, Catalonia, Spain). The basic tests performed for all CCDs were to obtain the photon transfer curve (PTC), the charge transfer efficiency (CTE) using X-rays and the EPER method, linearity, read-out noise, dark current, persistence, cosmetics and quantum efficiency. The X-rays images were also used for the analysis of the charge diffusion for different substrate voltages (VSUB). Regarding the cosmetics, and in addition to white and dark pixels, some patterns were also found. The first one, which appears in all devices, is the presence of half circles in the external edges. The origin of this pattern can be related to the assembly process. A second one appears in the dark images, and shows bright arcs connecting corners along the vertical axis of the CCD. This feature appears in all CCDs exactly in the same position so our guess is that the pattern is due to electrical fields. Finally, and just in two devices, there is a spot with wavelength dependence whose origin could be the result of a defectous coating process.

Wide-field direct CCD observations supporting the Astro-1 Space Shuttle mission's Ultraviolet Imaging Telescope

NASA Technical Reports Server (NTRS)

Hintzen, Paul; Angione, Ron; Talbert, Freddie; Cheng, K.-P.; Smith, Eric; Stecher, Theodore P.

1993-01-01

Wide field direct CCD observations are being obtained to support and complement the vacuum-ultraviolet (VUV) images provided by Astro's Ultraviolet Imaging Telescope (UIT) during a Space Shuttle flight in December 1990. Because of the wide variety of projects addressed by UIT, the fields observed include (1) galactic supernova remnants such as the Cygnus Loop and globular clusters such as Omega Cen and M79; (2) the Magellanic Clouds, M33, M81, and other galaxies in the Local Group; and (3) rich clusters of galaxies, principally the Perseus cluster and Abell 1367. Ground-based observations have been obtained for virtually all of the Astro-1 UIT fields. The optical images allow identification of individual UV sources in each field and provide the long baseline in wavelength necessary for accurate analysis of UV-bright sources. To facilitate use of our optical images for analysis of UIT data and other projects, we plan to archive them, with the UIT images, at the National Space Science Data Center (NSSDC), where they will be universally accessible via anonymous FTP. The UIT, one of three telescopes comprising the Astro spacecraft, is a 38-cm f/9 Ritchey-Chretien telescope on which high quantum efficiency, solar-blind image tubes are used to record VUV images on photographic film. Five filters with passbands centered between 1250A and 2500A provide both VUV colors and a measurement of extinction via the 2200A dust feature. The resulting calibrated VUV pictures are 40 arcminutes in diameter at 2.5 arcseconds resolution. The capabilities of UIT, therefore, complement HST's WFPC: the latter has 40 times greater collecting area, while UIT's usable field has 170 times WFPC's field area.

Proton radiation damage experiment on P-Channel CCD for an X-ray CCD camera onboard the ASTRO-H satellite

NASA Astrophysics Data System (ADS)

Mori, Koji; Nishioka, Yusuke; Ohura, Satoshi; Koura, Yoshiaki; Yamauchi, Makoto; Nakajima, Hiroshi; Ueda, Shutaro; Kan, Hiroaki; Anabuki, Naohisa; Nagino, Ryo; Hayashida, Kiyoshi; Tsunemi, Hiroshi; Kohmura, Takayoshi; Ikeda, Shoma; Murakami, Hiroshi; Ozaki, Masanobu; Dotani, Tadayasu; Maeda, Yukie; Sagara, Kenshi

2013-12-01

We report on a proton radiation damage experiment on P-channel CCD newly developed for an X-ray CCD camera onboard the ASTRO-H satellite. The device was exposed up to 109 protons cm-2 at 6.7 MeV. The charge transfer inefficiency (CTI) was measured as a function of radiation dose. In comparison with the CTI currently measured in the CCD camera onboard the Suzaku satellite for 6 years, we confirmed that the new type of P-channel CCD is radiation tolerant enough for space use. We also confirmed that a charge-injection technique and lowering the operating temperature efficiently work to reduce the CTI for our device. A comparison with other P-channel CCD experiments is also discussed. We performed a proton radiation damage experiment on a new P-channel CCD. The device was exposed up to 109 protons cm-2 at 6.7 MeV. We confirmed that it is radiation tolerant enough for space use. We confirmed that a charge-injection technique reduces the CTI. We confirmed that lowering the operating temperature also reduces the CTI.

Sacrificial charge and the spectral resolution performance of the Chandra advanced CCD imaging spectrometer

NASA Astrophysics Data System (ADS)

Grant, Catherine E.; Prigozhin, Gregory Y.; LaMarr, Beverly; Bautz, Mark W.

2003-03-01

Soon after launch, the Advanced CCD Imaging Spectrometer (ACIS), one of the focal plane instruments on the Chandra X-ray Observatory, suffered radiation damage from exposure to soft protons during passages through the Earth's radiation belts. The ACIS team is continuing to study the properties of the damage with an emphasis on developing techniques to mitigate charge transfer inefficiency (CTI) and spectral resolution degradation. A post-facto CTI corrector has been developed which can effectively recover much of the lost resolution. Any further improvements in performance will require knowledge of the location and amount of sacrificial charge - charge deposited along the readout path of an event which fills electron traps and changes CTI. We report on efforts by the ACIS Instrument team to characterize which charge traps cause performance degradation and the properties of the sacrificial charge seen on-orbit. We also report on attempts to correct X-ray pulseheights for the presence of sacrificial charge.

An Overview of the CBERS-2 Satellite and Comparison of the CBERS-2 CCD Data with the L5 TM Data

NASA Technical Reports Server (NTRS)

Chandler, Gyanesh

2007-01-01

CBERS satellite carries on-board a multi sensor payload with different spatial resolutions and collection frequencies. HRCCD (High Resolution CCD Camera), IRMSS (Infrared Multispectral Scanner), and WFI (Wide-Field Imager). The CCD and the WFI camera operate in the VNIR regions, while the IRMSS operates in SWIR and thermal region. In addition to the imaging payload, the satellite carries a Data Collection System (DCS) and Space Environment Monitor (SEM).

Cryostat and CCD for MEGARA at GTC

NASA Astrophysics Data System (ADS)

Castillo-Domínguez, E.; Ferrusca, D.; Tulloch, S.; Velázquez, M.; Carrasco, E.; Gallego, J.; Gil de Paz, A.; Sánchez, F. M.; Vílchez Medina, J. M.

2012-09-01

MEGARA (Multi-Espectrógrafo en GTC de Alta Resolución para Astronomía) is the new integral field unit (IFU) and multi-object spectrograph (MOS) instrument for the GTC. The spectrograph subsystems include the pseudo-slit, the shutter, the collimator with a focusing mechanism, pupil elements on a volume phase holographic grating (VPH) wheel and the camera joined to the cryostat through the last lens, with a CCD detector inside. In this paper we describe the full preliminary design of the cryostat which will harbor the CCD detector for the spectrograph. The selected cryogenic device is an LN2 open-cycle cryostat which has been designed by the "Astronomical Instrumentation Lab for Millimeter Wavelengths" at INAOE. A complete description of the cryostat main body and CCD head is presented as well as all the vacuum and temperature sub-systems to operate it. The CCD is surrounded by a radiation shield to improve its performance and is placed in a custom made mechanical mounting which will allow physical adjustments for alignment with the spectrograph camera. The 4k x 4k pixel CCD231 is our selection for the cryogenically cooled detector of MEGARA. The characteristics of this CCD, the internal cryostat cabling and CCD controller hardware are discussed. Finally, static structural finite element modeling and thermal analysis results are shown to validate the cryostat model.

The 2-d CCD Data Reduction Cookbook

NASA Astrophysics Data System (ADS)

Davenhall, A. C.; Privett, G. J.; Taylor, M. B.

This cookbook presents simple recipes and scripts for reducing direct images acquired with optical CCD detectors. Using these recipes and scripts you can correct un-processed images obtained from CCDs for various instrumental effects to retrieve an accurate picture of the field of sky observed. The recipes and scripts use standard software available at all Starlink sites. The topics covered include: creating and applying bias and flat-field corrections, registering frames and creating a stack or mosaic of registered frames. Related auxiliary tasks, such as converting between different data formats, displaying images and calculating image statistics are also presented. In addition to the recipes and scripts, sufficient background material is presented to explain the procedures and techniques used. The treatment is deliberately practical rather than theoretical, in keeping with the aim of providing advice on the actual reduction of observations. Additional material outlines some of the differences between using conventional optical CCDs and the similar arrays used to observe at infrared wavelengths.

Experimental research on femto-second laser damaging array CCD cameras

NASA Astrophysics Data System (ADS)

Shao, Junfeng; Guo, Jin; Wang, Ting-feng; Wang, Ming

2013-05-01

Charged Coupled Devices (CCD) are widely used in military and security applications, such as airborne and ship based surveillance, satellite reconnaissance and so on. Homeland security requires effective means to negate these advanced overseeing systems. Researches show that CCD based EO systems can be significantly dazzled or even damaged by high-repetition rate pulsed lasers. Here, we report femto - second laser interaction with CCD camera, which is probable of great importance in future. Femto - second laser is quite fresh new lasers, which has unique characteristics, such as extremely short pulse width (1 fs = 10-15 s), extremely high peak power (1 TW = 1012W), and especially its unique features when interacting with matters. Researches in femto second laser interaction with materials (metals, dielectrics) clearly indicate non-thermal effect dominates the process, which is of vast difference from that of long pulses interaction with matters. Firstly, the damage threshold test are performed with femto second laser acting on the CCD camera. An 800nm, 500μJ, 100fs laser pulse is used to irradiate interline CCD solid-state image sensor in the experiment. In order to focus laser energy onto tiny CCD active cells, an optical system of F/5.6 is used. A Sony production CCDs are chose as typical targets. The damage threshold is evaluated with multiple test data. Point damage, line damage and full array damage were observed when the irradiated pulse energy continuously increase during the experiment. The point damage threshold is found 151.2 mJ/cm2.The line damage threshold is found 508.2 mJ/cm2.The full-array damage threshold is found to be 5.91 J/cm2. Although the phenomenon is almost the same as that of nano laser interaction with CCD, these damage thresholds are substantially lower than that of data obtained from nano second laser interaction with CCD. Then at the same time, the electric features after different degrees of damage are tested with electronic multi

Social image quality

NASA Astrophysics Data System (ADS)

Qiu, Guoping; Kheiri, Ahmed

2011-01-01

Current subjective image quality assessments have been developed in the laboratory environments, under controlledconditions, and are dependent on the participation of limited numbers of observers. In this research, with the help of Web 2.0 and social media technology, a new method for building a subjective image quality metric has been developed where the observers are the Internet users. A website with a simple user interface that enables Internet users from anywhere at any time to vote for a better quality version of a pair of the same image has been constructed. Users' votes are recorded and used to rank the images according to their perceived visual qualities. We have developed three rank aggregation algorithms to process the recorded pair comparison data, the first uses a naive approach, the second employs a Condorcet method, and the third uses the Dykstra's extension of Bradley-Terry method. The website has been collecting data for about three months and has accumulated over 10,000 votes at the time of writing this paper. Results show that the Internet and its allied technologies such as crowdsourcing offer a promising new paradigm for image and video quality assessment where hundreds of thousands of Internet users can contribute to building more robust image quality metrics. We have made Internet user generated social image quality (SIQ) data of a public image database available online (http://www.hdri.cs.nott.ac.uk/siq/) to provide the image quality research community with a new source of ground truth data. The website continues to collect votes and will include more public image databases and will also be extended to include videos to collect social video quality (SVQ) data. All data will be public available on the website in due course.

Design and development of a fiber optic TDI CCD-based slot-scan digital mammography system

NASA Astrophysics Data System (ADS)

Toker, Emre; Piccaro, Michele F.

1993-12-01

We previously reported on the development, design, and clinical evaluation of a CCD-based, high performance, filmless imaging system for stereotactic needle biopsy procedures in mammography. The MammoVision system has a limited imaging area of 50 mm X 50 mm, since it is designed specifically for breast biopsy applications. We are currently developing a new filmless imaging system designed to cover the 18 cm X 24 cm imaging area required for screening and diagnostic mammography. The diagnostic mammography system is based on four 1100 X 330 pixel format, full-frame, scientific grade, front illuminated, MPP mode CCDs, with 24 micrometers X 24 micrometers square pixels Each CCD is coupled to an x-ray intensifying screen via a 1.7:1 fiber optic reducer. The detector assembly (180 mm long and 13.5 mm wide) is scanned across the patient's breast synchronously with the x-ray source, with the CCDs operated in time-delay integration (TDI) mode. The total scan time is 4.0 seconds.

Multicolor CCD photometry of the open cluster NGC 752

NASA Astrophysics Data System (ADS)

Bartašiūtė, Stanislava; Janusz, Robert; Boyle, Richard P.; Philip, A. G. Davis; Deveikis, Viktoras

2010-01-01

We obtained CCD observations of the open cluster NGC 752 with the 1.8m Vatican Advanced Technology Telescope (Mt. Graham, Arizona) with a 4K CCD camera and eight intermediate-band filters of the Stromvil (Strömgren + Vilnius) system. Four 12‧ × 12‧ fields were observed, covering the central part of the cluster. The good-quality multicolor data made it possible to obtain precise estimates of distance moduli, metallicity and foreground reddening for individual stars down to the limiting magnitude, V = 17.5, enabling photometric identification of faint cluster members. The new observations provide an extension of the lower main sequence to three magnitudes beyond the previous (photographic) limit. A relatively small number of photometric members identified at fainter magnitudes seems to be indicative of actual dissolution of the cluster from the low-mass end.

Silicide Schottky Barrier For Back-Surface-Illuminated CCD

NASA Technical Reports Server (NTRS)

Hecht, Michael H.

1990-01-01

Quantum efficiency of back-surface-illuminated charge-coupled device (CCD) increased by coating back surface with thin layer of PtSi or IrSi on thin layer of SiO2. In its interaction with positively-doped bulk Si of CCD, silicide/oxide layer forms Schottky barrier that repels electrons, promoting accumulation of photogenerated charge carriers in front-side CCD potential wells. Physical principle responsible for improvement explained in "Metal Film Increases CCD Output" (NPO-16815).

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.

Comparison of lens- and fiber-coupled CCD detectors for X-ray computed tomography

PubMed Central

Uesugi, K.; Hoshino, M.; Yagi, N.

2011-01-01

X-ray imaging detectors with an identical phosphor and a CCD chip but employing lens- and fiber-coupling between them have been compared. These are designed for X-ray imaging experiments, especially computed tomography, at the medium-length beamline at the SPring-8 synchrotron radiation facility. It was found that the transmittance of light to the CCD is about four times higher in the fiber-coupled detector. The uniformity of response in the lens-coupled detector has a global shading of up to 40%, while pixel-to-pixel variation owing to a chicken-wire pattern was dominant in the fiber-coupled detector. Apart from the higher transmittance, the fiber-coupled detector has a few characteristics that require attention when it is used for computed tomography, which are browning of the fiber, discontinuity in the image, image distortion, and dark spots in the chicken-wire pattern. Thus, it is most suitable for high-speed tomography of samples that tend to deform, for example biological and soft materials. PMID:21335908

The design and development of low- and high-voltage ASICs for space-borne CCD cameras

NASA Astrophysics Data System (ADS)

Waltham, N.; Morrissey, Q.; Clapp, M.; Bell, S.; Jones, L.; Torbet, M.

2017-12-01

The CCD remains the pre-eminent visible and UV wavelength image sensor in space science, Earth and planetary remote sensing. However, the design of space-qualified CCD readout electronics is a significant challenge with requirements for low-volume, low-mass, low-power, high-reliability and tolerance to space radiation. Space-qualified components are frequently unavailable and up-screened commercial components seldom meet project or international space agency requirements. In this paper, we describe an alternative approach of designing and space-qualifying a series of low- and high-voltage mixed-signal application-specific integrated circuits (ASICs), the ongoing development of two low-voltage ASICs with successful flight heritage, and two new high-voltage designs. A challenging sub-system of any CCD camera is the video processing and digitisation electronics. We describe recent developments to improve performance and tolerance to radiation-induced single event latchup of a CCD video processing ASIC originally developed for NASA's Solar Terrestrial Relations Observatory and Solar Dynamics Observatory. We also describe a programme to develop two high-voltage ASICs to address the challenges presented with generating a CCD's bias voltages and drive clocks. A 0.35 μm, 50 V tolerant, CMOS process has been used to combine standard low-voltage 3.3 V transistors with high-voltage 50 V diffused MOSFET transistors that enable output buffers to drive CCD bias drains, gates and clock electrodes directly. We describe a CCD bias voltage generator ASIC that provides 24 independent and programmable 0-32 V outputs. Each channel incorporates a 10-bit digital-to-analogue converter, provides current drive of up to 20 mA into loads of 10 μF, and includes current-limiting and short-circuit protection. An on-chip telemetry system with a 12-bit analogue-to-digital converter enables the outputs and multiple off-chip camera voltages to be monitored. The ASIC can drive one or more CCDs and

SCP -- A Simple CCD Processing Package

NASA Astrophysics Data System (ADS)

Lewis, J. R.

This note describes a small set of programs, written at RGO, which deal with basic CCD frame processing (e.g. bias subtraction, flat fielding, trimming etc.). The need to process large numbers of CCD frames from devices such as FOS or ISIS in order to extract spectra has prompted the writing of routines which will do the basic hack-work with a minimal amount of interaction from the user. Although they were written with spectral data in mind, there are no ``spectrum-specific'' features in the software which means they can be applied to any CCD data.

CCD-photometry of comets at large heliocentric distances

NASA Technical Reports Server (NTRS)

Mueller, Beatrice E. A.

1992-01-01

CCD imaging and time series photometry are used to determine the state of activity, nuclear properties and eventually the rotational motion of cometary nuclei. Cometary activity at large heliocentric distances and mantle evolution are not yet fully understood. Results of observations carried out at the 2.1 telescope on Kitt Peak April 10-12 and May 15-16, 1991 are discussed. Color values and color-color diagrams are presented for several comets and asteroids. Estimations of nuclear radii and shapes are given.

Multipurpose Hyperspectral Imaging System

NASA Technical Reports Server (NTRS)

Mao, Chengye; Smith, David; Lanoue, Mark A.; Poole, Gavin H.; Heitschmidt, Jerry; Martinez, Luis; Windham, William A.; Lawrence, Kurt C.; Park, Bosoon

2005-01-01

A hyperspectral imaging system of high spectral and spatial resolution that incorporates several innovative features has been developed to incorporate a focal plane scanner (U.S. Patent 6,166,373). This feature enables the system to be used for both airborne/spaceborne and laboratory hyperspectral imaging with or without relative movement of the imaging system, and it can be used to scan a target of any size as long as the target can be imaged at the focal plane; for example, automated inspection of food items and identification of single-celled organisms. The spectral resolution of this system is greater than that of prior terrestrial multispectral imaging systems. Moreover, unlike prior high-spectral resolution airborne and spaceborne hyperspectral imaging systems, this system does not rely on relative movement of the target and the imaging system to sweep an imaging line across a scene. This compact system (see figure) consists of a front objective mounted at a translation stage with a motorized actuator, and a line-slit imaging spectrograph mounted within a rotary assembly with a rear adaptor to a charged-coupled-device (CCD) camera. Push-broom scanning is carried out by the motorized actuator which can be controlled either manually by an operator or automatically by a computer to drive the line-slit across an image at a focal plane of the front objective. To reduce the cost, the system has been designed to integrate as many as possible off-the-shelf components including the CCD camera and spectrograph. The system has achieved high spectral and spatial resolutions by using a high-quality CCD camera, spectrograph, and front objective lens. Fixtures for attachment of the system to a microscope (U.S. Patent 6,495,818 B1) make it possible to acquire multispectral images of single cells and other microscopic objects.

Follow-up study of children with cerebral coordination disturbance (CCD, Vojta).

PubMed

Imamura, S; Sakuma, K; Takahashi, T

1983-01-01

713 children (from newborn to 12-month-old) with delayed motor development were carefully examined and classified into normal, very light cerebral coordination disturbance (CCD, Vojta), light CCD, moderate CCD, severe CCD, suspected cerebral palsy (CP) and other diseases at their first visit, and were followed up carefully. Finally, 89.0% of very light CCD, 71.4% of light CCD, 56.0% of moderate CCD and 30.0% of severe CCD developed into normal. 59.5% of moderate CCD and 45.5% of severe CCD among children who were given Vojta's physiotherapy developed into normal. The classification of cases with delayed motor development into very light, light, moderate and severe CCD based on the extent of abnormality in their postural reflexes is useful and well correlated with their prognosis. Treatment by Vojta's method seems to be efficient and helpful for young children with delayed motor development.

CCD Camera Lens Interface for Real-Time Theodolite Alignment

NASA Technical Reports Server (NTRS)

Wake, Shane; Scott, V. Stanley, III

2012-01-01

Theodolites are a common instrument in the testing, alignment, and building of various systems ranging from a single optical component to an entire instrument. They provide a precise way to measure horizontal and vertical angles. They can be used to align multiple objects in a desired way at specific angles. They can also be used to reference a specific location or orientation of an object that has moved. Some systems may require a small margin of error in position of components. A theodolite can assist with accurately measuring and/or minimizing that error. The technology is an adapter for a CCD camera with lens to attach to a Leica Wild T3000 Theodolite eyepiece that enables viewing on a connected monitor, and thus can be utilized with multiple theodolites simultaneously. This technology removes a substantial part of human error by relying on the CCD camera and monitors. It also allows image recording of the alignment, and therefore provides a quantitative means to measure such error.

CCD-Based Skinning Injury Recognition on Potato Tubers (Solanum tuberosum L.): A Comparison between Visible and Biospeckle Imaging

PubMed Central

Gao, Yingwang; Geng, Jinfeng; Rao, Xiuqin; Ying, Yibin

2016-01-01

Skinning injury on potato tubers is a kind of superficial wound that is generally inflicted by mechanical forces during harvest and postharvest handling operations. Though skinning injury is pervasive and obstructive, its detection is very limited. This study attempted to identify injured skin using two CCD (Charge Coupled Device) sensor-based machine vision technologies, i.e., visible imaging and biospeckle imaging. The identification of skinning injury was realized via exploiting features extracted from varied ROIs (Region of Interests). The features extracted from visible images were pixel-wise color and texture features, while region-wise BA (Biospeckle Activity) was calculated from biospeckle imaging. In addition, the calculation of BA using varied numbers of speckle patterns were compared. Finally, extracted features were implemented into classifiers of LS-SVM (Least Square Support Vector Machine) and BLR (Binary Logistic Regression), respectively. Results showed that color features performed better than texture features in classifying sound skin and injured skin, especially for injured skin stored no less than 1 day, with the average classification accuracy of 90%. Image capturing and processing efficiency can be speeded up in biospeckle imaging, with captured 512 frames reduced to 125 frames. Classification results obtained based on the feature of BA were acceptable for early skinning injury stored within 1 day, with the accuracy of 88.10%. It is concluded that skinning injury can be recognized by visible and biospeckle imaging during different stages. Visible imaging has the aptitude in recognizing stale skinning injury, while fresh injury can be discriminated by biospeckle imaging. PMID:27763555

CCD-Based Skinning Injury Recognition on Potato Tubers (Solanum tuberosum L.): A Comparison between Visible and Biospeckle Imaging.

PubMed

Gao, Yingwang; Geng, Jinfeng; Rao, Xiuqin; Ying, Yibin

2016-10-18

Skinning injury on potato tubers is a kind of superficial wound that is generally inflicted by mechanical forces during harvest and postharvest handling operations. Though skinning injury is pervasive and obstructive, its detection is very limited. This study attempted to identify injured skin using two CCD (Charge Coupled Device) sensor-based machine vision technologies, i.e., visible imaging and biospeckle imaging. The identification of skinning injury was realized via exploiting features extracted from varied ROIs (Region of Interests). The features extracted from visible images were pixel-wise color and texture features, while region-wise BA (Biospeckle Activity) was calculated from biospeckle imaging. In addition, the calculation of BA using varied numbers of speckle patterns were compared. Finally, extracted features were implemented into classifiers of LS-SVM (Least Square Support Vector Machine) and BLR (Binary Logistic Regression), respectively. Results showed that color features performed better than texture features in classifying sound skin and injured skin, especially for injured skin stored no less than 1 day, with the average classification accuracy of 90%. Image capturing and processing efficiency can be speeded up in biospeckle imaging, with captured 512 frames reduced to 125 frames. Classification results obtained based on the feature of BA were acceptable for early skinning injury stored within 1 day, with the accuracy of 88.10%. It is concluded that skinning injury can be recognized by visible and biospeckle imaging during different stages. Visible imaging has the aptitude in recognizing stale skinning injury, while fresh injury can be discriminated by biospeckle imaging.

VizieR Online Data Catalog: NGC 225 CCD UBV photometry (Bilir+, 2016)

NASA Astrophysics Data System (ADS)

Bilir, S.; Bostanci, Z. F.; Yontan, T.; Guver, T.; Bakis, V.; Ak, T.; Ak, S.; Paunzen, E.; Eker, Z.

2016-11-01

CCD UBVRI images of the open cluster NGC 225 and standard stars selected from Landolt (2009, Cat. J/AJ/137/4186) were acquired on 2012 July 18 using a 1-m Ritchey-Chretien telescope (T100) located at the TUBITAK National Observatory (TUG) in Bakirlitepe, Antalya/Turkey. (1 data file).

VizieR Online Data Catalog: NGC 6819 CCD UBV photometry (Ak+, 2016)

NASA Astrophysics Data System (ADS)

Ak, T.; Bostanci, Z. F.; Yontan, T.; Bilir, S.; Guver, T.; Ak, S.; Urgup, H.; Paunzen, E.

2016-11-01

CCD UBVRI images of the open cluster NGC 6819 and standard stars selected from Landolt (2009, Cat. J/AJ/137/4186) were acquired on 2015 May 18 using a 1-m Ritchey-Chretien telescope (T100) located at the TUBITAK National Observatory (TUG) in Bakirlitepe, Antalya/Turkey. (1 data file).

Apical dominance in saffron and the involvement of the branching enzymes CCD7 and CCD8 in the control of bud sprouting

PubMed Central

2014-01-01

Background In saffron (Crocus sativus), new corms develop at the base of every shoot developed from the maternal corm, a globular underground storage stem. Since the degree of bud sprouts influences the number and size of new corms, and strigolactones (SLs) suppress growth of pre-formed axillary bud, it was considered appropriate to investigate SL involvement in physiology and molecular biology in saffron. We focused on two of the genes within the SL pathway, CCD7 and CCD8, encoding carotenoid cleavage enzymes required for the production of SLs. Results The CsCCD7 and CsCCD8 genes are the first ones isolated and characterized from a non-grass monocotyledonous plant. CsCCD7 and CsCCD8 expression showed some overlapping, although they were not identical. CsCCD8 was highly expressed in quiescent axillary buds and decapitation dramatically reduced its expression levels, suggesting its involvement in the suppression of axillary bud outgrowth. Furthermore, in vitro experiments showed also the involvement of auxin, cytokinin and jasmonic acid on the sprouting of axillary buds from corms in which the apical bud was removed. In addition, CsCCD8 expression, but not CsCCD7, was higher in the newly developed vascular tissue of axillary buds compared to the vascular tissue of the apical bud. Conclusions We showed that production and transport of auxin in saffron corms could act synergistically with SLs to arrest the outgrowth of the axillary buds, similar to the control of above-ground shoot branching. In addition, jasmonic acid seems to play a prominent role in bud dormancy in saffron. While cytokinins from roots promote bud outgrowth. In addition the expression results of CsCCD8 suggest that SLs could positively regulate procambial activity and the development of new vascular tissues connecting leaves with the mother corm. PMID:24947472

Deep Sky Imaging: Workflow 2

NASA Astrophysics Data System (ADS)

Schedler, Johannes

As astrophotographers we are living in a golden age. In recent years CCD technology and the quality of amateur telescopes have reached a level of perfection, giving amateurs the chance to produce images rivaling those taken from mountaintops by large professional systems as recently as two decades ago. However hardware and good imaging location is only a part of the game. A high level of skill with image processing can offer amateurs an edge and provide a chance to compensate for the limited aperture of our telescopes.

Direct detection of x-rays for protein crystallography employing a thick, large area CCD

DOEpatents

Atac, Muzaffer; McKay, Timothy

1999-01-01

An apparatus and method for directly determining the crystalline structure of a protein crystal. The crystal is irradiated by a finely collimated x-ray beam. The interaction of the x-ray beam with the crystal produces scattered x-rays. These scattered x-rays are detected by means of a large area, thick CCD which is capable of measuring a significant number of scattered x-rays which impact its surface. The CCD is capable of detecting the position of impact of the scattered x-ray on the surface of the CCD and the quantity of scattered x-rays which impact the same cell or pixel. This data is then processed in real-time and the processed data is outputted to produce a image of the structure of the crystal. If this crystal is a protein the molecular structure of the protein can be determined from the data received.

Qualification process of CR system and quantification of digital image quality

NASA Astrophysics Data System (ADS)

Garnier, P.; Hun, L.; Klein, J.; Lemerle, C.

2013-01-01

CEA Valduc uses several X-Ray generators to carry out many inspections: void search, welding expertise, gap measurements, etc. Most of these inspections are carried out on silver based plates. For several years, the CEA/Valduc has decided to qualify new devices such as digital plates or CCD/flat panel plates. On one hand, the choice of this technological orientation is to forecast the assumed and eventual disappearance of silver based plates; on the other hand, it is also to keep our skills mastering up-to-date. The main improvement brought by numerical plates is the continuous progress of the measurement accuracy, especially with image data processing. It is now common to measure defects thickness or depth position within a part. In such applications, data image processing is used to obtain complementary information compared to scanned silver based plates. This scanning procedure is harmful for measurements which imply a data corruption of the resolution, the adding of numerical noise and is time expensive. Digital plates enable to suppress the scanning procedure and to increase resolution. It is nonetheless difficult to define, for digital images, single criteria for the image quality. A procedure has to be defined in order to estimate quality of the digital data itself; the impact of the scanning device and the configuration parameters are also to be taken into account. This presentation deals with the qualification process developed by CEA/Valduc for digital plates (DUR-NDT) based on the study of quantitative criteria chosen to define a direct numerical image quality that could be compared with scanned silver based pictures and the classical optical density. The versatility of the X-Ray parameters is also discussed (X-ray tension, intensity, time exposure). The aim is to be able to transfer the year long experience of CEA/Valduc with silver-based plates inspection to these new digital plates supports. This is an industrial stake.

Spectral analysis using the CCD Chirp Z-transform

NASA Technical Reports Server (NTRS)

Eversole, W. L.; Mayer, D. J.; Bosshart, P. W.; Dewit, M.; Howes, C. R.; Buss, D. D.

1978-01-01

The charge coupled device (CCD) Chirp Z transformation (CZT) spectral analysis techniques were reviewed and results on state-of-the-art CCD CZT technology are presented. The CZT algorithm was examined and the advantages of CCD implementation are discussed. The sliding CZT which is useful in many spectral analysis applications is described, and the performance limitations of the CZT are studied.

Is flat fielding safe for precision CCD astronomy?

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

Baumer, Michael; Davis, Christopher P.; Roodman, Aaron

The ambitious goals of precision cosmology with wide-field optical surveys such as the Dark Energy Survey (DES) and the Large Synoptic Survey Telescope (LSST) demand precision CCD astronomy as their foundation. This in turn requires an understanding of previously uncharacterized sources of systematic error in CCD sensors, many of which manifest themselves as static effective variations in pixel area. Such variation renders a critical assumption behind the traditional procedure of flat fielding—that a sensor's pixels comprise a uniform grid—invalid. In this work, we present a method to infer a curl-free model of a sensor's underlying pixel grid from flat-field images,more » incorporating the superposition of all electrostatic sensor effects—both known and unknown—present in flat-field data. We use these pixel grid models to estimate the overall impact of sensor systematics on photometry, astrometry, and PSF shape measurements in a representative sensor from the Dark Energy Camera (DECam) and a prototype LSST sensor. Applying the method to DECam data recovers known significant sensor effects for which corrections are currently being developed within DES. For an LSST prototype CCD with pixel-response non-uniformity (PRNU) of 0.4%, we find the impact of "improper" flat fielding on these observables is negligible in nominal .7'' seeing conditions. Furthermore, these errors scale linearly with the PRNU, so for future LSST production sensors, which may have larger PRNU, our method provides a way to assess whether pixel-level calibration beyond flat fielding will be required.« less

Is flat fielding safe for precision CCD astronomy?

DOE PAGES

Baumer, Michael; Davis, Christopher P.; Roodman, Aaron

2017-07-06

The ambitious goals of precision cosmology with wide-field optical surveys such as the Dark Energy Survey (DES) and the Large Synoptic Survey Telescope (LSST) demand precision CCD astronomy as their foundation. This in turn requires an understanding of previously uncharacterized sources of systematic error in CCD sensors, many of which manifest themselves as static effective variations in pixel area. Such variation renders a critical assumption behind the traditional procedure of flat fielding—that a sensor's pixels comprise a uniform grid—invalid. In this work, we present a method to infer a curl-free model of a sensor's underlying pixel grid from flat-field images,more » incorporating the superposition of all electrostatic sensor effects—both known and unknown—present in flat-field data. We use these pixel grid models to estimate the overall impact of sensor systematics on photometry, astrometry, and PSF shape measurements in a representative sensor from the Dark Energy Camera (DECam) and a prototype LSST sensor. Applying the method to DECam data recovers known significant sensor effects for which corrections are currently being developed within DES. For an LSST prototype CCD with pixel-response non-uniformity (PRNU) of 0.4%, we find the impact of "improper" flat fielding on these observables is negligible in nominal .7'' seeing conditions. Furthermore, these errors scale linearly with the PRNU, so for future LSST production sensors, which may have larger PRNU, our method provides a way to assess whether pixel-level calibration beyond flat fielding will be required.« less

A CCD search for geosynchronous debris

NASA Technical Reports Server (NTRS)

Gehrels, Tom; Vilas, Faith

1986-01-01

Using the Spacewatch Camera, a search was conducted for objects in geosynchronous earth orbit. The system is equipped with a CCD camera cooled with dry ice; the image scale is 1.344 arcsec/pixel. The telescope drive was off so that during integrations the stars were trailed while geostationary objects appeared as round images. The technique should detect geostationary objects to a limiting apparent visual magnitude of 19. A sky area of 8.8 square degrees was searched for geostationary objects while geosynchronous debris passing through was 16.4 square degrees. Ten objects were found of which seven are probably geostationary satellites having apparent visual magnitudes brighter than 13.1. Three objects having magnitudes equal to or fainter than 13.7 showed motion in the north-south direction. The absence of fainter stationary objects suggests that a gap in debris size exists between satellites and particles having diameters in the millimeter range.

Easily Transported CCD Systems for Use in Astronomy Labs

NASA Astrophysics Data System (ADS)

Meisel, D.

1992-12-01

Relatively inexpensive CCD cameras and portable computers are now easily obtained as commercially available products. I will describe a prototype system that can be used by introductory astronomy students, even urban enviroments, to obtain useful observations of the night sky. It is based on the ST-4 CCDs made by Santa Barbara Instruments Group and Macintosh Powerbook145 computers. Students take outdoor images directly from the college campus, bring the exposures back into the lab and download the images into our networked server. These stored images can then be processed (at a later time) using a variety of image processing programs including a new astronomical version of the popular "freeware" NIH Image package that is currently under development at Geneseo. The prototype of this system will be demonstrated and available for hands-on use during the meeting. This work is supported by NSF ILI Demonstration Grant USE9250493 and Grants from SUNY-GENESEO.

CCD BVI c observations of Cepheids

NASA Astrophysics Data System (ADS)

Berdnikov, L. N.; Kniazev, A. Yu.; Sefako, R.; Kravtsov, V. V.; Zhujko, S. V.

2014-02-01

In 2008-2013, we obtained 11333 CCD BVI c frames for 57 Cepheids from the General Catalogue of Variable Stars. We performed our observations with the 76-cm telescope of the South African Astronomical Observatory (SAAO, South Africa) and the 40-cm telescope of the Cerro Armazones Astronomical Observatory of the Universidad Católica del Norte (OCA, Chile) using the SBIG ST-10XME CCD camera. The tables of observations, the plots of light curves, and the current light elements are presented. Comparison of our light curves with those constructed from photoelectric observations shows that the differences between their mean magnitudes exceed 0ṃ05 in 20% of the cases. This suggests the necessity of performing CCD observations for all Cepheids.

Application of CCD drift-scan photoelectric technique on monitoring GEO satellites

NASA Astrophysics Data System (ADS)

Yu, Yong; Zhao, Xiao-Fen; Luo, Hao; Mao, Yin-Dun; Tang, Zheng-Hong

2018-05-01

Geosynchronous Earth Orbit (GEO) satellites are widely used because of their unique characteristics of high-orbit and remaining permanently in the same area of the sky. Precise monitoring of GEO satellites can provide a key reference for the judgment of satellite operation status, the capture and identification of targets, and the analysis of collision warning. The observation using ground-based optical telescopes plays an important role in the field of monitoring GEO targets. Different from distant celestial bodies, there is a relative movement between the GEO target and the background reference stars, which makes the conventional observation method limited for long focal length telescopes. CCD drift-scan photoelectric technique is applied on monitoring GEO targets. In the case of parking the telescope, the good round images of the background reference stars and the GEO target at the same sky region can be obtained through the alternating observation of CCD drift-scan mode and CCD stare mode, so as to improve the precision of celestial positioning for the GEO target. Observation experiments of GEO targets were carried out with 1.56-meter telescope of Shanghai Astronomical Observatory. The results show that the application of CCD drift-scan photoelectric technique makes the precision of observing the GEO target reach the level of 0.2″, which gives full play to the advantage of the long focal length of the telescope. The effect of orbit improvement based on multi-pass of observations is obvious and the prediction precision of extrapolating to 72-h is in the order of several arc seconds in azimuth and elevation.

Robotic CCD microscope for enhanced crystal recognition

DOEpatents

Segelke, Brent W.; Toppani, Dominique

2007-11-06

A robotic CCD microscope and procedures to automate crystal recognition. The robotic CCD microscope and procedures enables more accurate crystal recognition, leading to fewer false negative and fewer false positives, and enable detection of smaller crystals compared to other methods available today.

A USB 2.0 computer interface for the UCO/Lick CCD cameras

NASA Astrophysics Data System (ADS)

Wei, Mingzhi; Stover, Richard J.

2004-09-01

The new UCO/Lick Observatory CCD camera uses a 200 MHz fiber optic cable to transmit image data and an RS232 serial line for low speed bidirectional command and control. Increasingly RS232 is a legacy interface supported on fewer computers. The fiber optic cable requires either a custom interface board that is plugged into the mainboard of the image acquisition computer to accept the fiber directly or an interface converter that translates the fiber data onto a widely used standard interface. We present here a simple USB 2.0 interface for the UCO/Lick camera. A single USB cable connects to the image acquisition computer and the camera's RS232 serial and fiber optic cables plug into the USB interface. Since most computers now support USB 2.0 the Lick interface makes it possible to use the camera on essentially any modern computer that has the supporting software. No hardware modifications or additions to the computer are needed. The necessary device driver software has been written for the Linux operating system which is now widely used at Lick Observatory. The complete data acquisition software for the Lick CCD camera is running on a variety of PC style computers as well as an HP laptop.

Spatial resolution of a hard x-ray CCD detector.

PubMed

Seely, John F; Pereira, Nino R; Weber, Bruce V; Schumer, Joseph W; Apruzese, John P; Hudson, Lawrence T; Szabo, Csilla I; Boyer, Craig N; Skirlo, Scott

2010-08-10

The spatial resolution of an x-ray CCD detector was determined from the widths of the tungsten x-ray lines in the spectrum formed by a crystal spectrometer in the 58 to 70 keV energy range. The detector had 20 microm pixel, 1700 by 1200 pixel format, and a CsI x-ray conversion scintillator. The spectral lines from a megavolt x-ray generator were focused on the spectrometer's Rowland circle by a curved transmission crystal. The line shapes were Lorentzian with an average width after removal of the natural and instrumental line widths of 95 microm (4.75 pixels). A high spatial frequency background, primarily resulting from scattered gamma rays, was removed from the spectral image by Fourier analysis. The spectral lines, having low spatial frequency in the direction perpendicular to the dispersion, were enhanced by partially removing the Lorentzian line shape and by fitting Lorentzian curves to broad unresolved spectral features. This demonstrates the ability to improve the spectral resolution of hard x-ray spectra that are recorded by a CCD detector with well-characterized intrinsic spatial resolution.

CCD developments for particle colliders

NASA Astrophysics Data System (ADS)

Stefanov, Konstantin D.

2006-09-01

Charge Coupled Devices (CCDs) have been successfully used in several high-energy physics experiments over the last 20 years. Their small pixel size and excellent precision provide superb tool for studying of short-lived particles and understanding the nature at fundamental level. Over the last years the Linear Collider Flavour Identification (LCFI) collaboration has developed Column-Parallel CCDs (CPCCD) and CMOS readout chips to be used for the vertex detector at the International Linear Collider (ILC). The CPCCDs are very fast devices capable of satisfying the challenging requirements imposed by the beam structure of the superconducting accelerator. First set of prototype devices have been designed, manufactured and successfully tested, with second-generation chips on the way. Another idea for CCD-based device, the In-situ Storage Image Sensor (ISIS) is also under development and the first prototype is in production.

2060 Chiron - CCD and electronographic photometry

NASA Technical Reports Server (NTRS)

Bus, Schelte J.; Bowell, Edward; Harris, Alan W.; Hewitt, Anthony V.

1989-01-01

R-band observations conducted for 2060 Chiron using CCD photometry in November-December 1986 and March 1988 are discussed. While the 1986 observations exhibit neither periodic nor nonperiodic brightness changes ascribable to comet-like activity, the 1988 observations show an 0.6 + or - 0.1 mag brightening that confirms the Tholen et al. (1988) findings and is consistent with the 1978 electronographic photometry presented. The lightcurve amplitudes appear, however, to have remained unchanged from 1978 to 1988, and the image profiles from 1978 are indistinguishable from the stars in 1986 and 1988. It is suggested that Chiron has either been varying nonasteroidally of late, on a 1-2 month timescale, or its intrinsic brightness has been bistable over the past decade.

CCD Photometer Installed on the Telescope - 600 OF the Shamakhy Astrophysical Observatory II. The Technique of Observation and Data Processing of CCD Photometry

NASA Astrophysics Data System (ADS)

Abdullayev, B. I.; Gulmaliyev, N. I.; Majidova, S. O.; Mikayilov, Kh. M.; Rustamov, B. N.

2009-12-01

Basic technical characteristics of CCD matrix U-47 made by the Apogee Alta Instruments Inc. are provided. Short description and features of various noises introduced by optical system and CCD camera are presented. The technique of getting calibration frames: bias, dark, flat field and main stages of processing of results CCD photometry are described.

Optimized algorithm for the spatial nonuniformity correction of an imaging system based on a charge-coupled device color camera.

PubMed

de Lasarte, Marta; Pujol, Jaume; Arjona, Montserrat; Vilaseca, Meritxell

2007-01-10

We present an optimized linear algorithm for the spatial nonuniformity correction of a CCD color camera's imaging system and the experimental methodology developed for its implementation. We assess the influence of the algorithm's variables on the quality of the correction, that is, the dark image, the base correction image, and the reference level, and the range of application of the correction using a uniform radiance field provided by an integrator cube. The best spatial nonuniformity correction is achieved by having a nonzero dark image, by using an image with a mean digital level placed in the linear response range of the camera as the base correction image and taking the mean digital level of the image as the reference digital level. The response of the CCD color camera's imaging system to the uniform radiance field shows a high level of spatial uniformity after the optimized algorithm has been applied, which also allows us to achieve a high-quality spatial nonuniformity correction of captured images under different exposure conditions.

Characterization of a parallel beam CCD optical-CT apparatus for 3D radiation dosimetry

NASA Astrophysics Data System (ADS)

Krstajić, Nikola; Doran, Simon J.

2006-12-01

This paper describes the initial steps we have taken in establishing CCD based optical-CT as a viable alternative for 3-D radiation dosimetry. First, we compare the optical density (OD) measurements from a high quality test target and variable neutral density filter (VNDF). A modulation transfer function (MTF) of individual projections is derived for three positions of the sinusoidal test target within the scanning tank. Our CCD is then characterized in terms of its signal-to-noise ratio (SNR). Finally, a sample reconstruction of a scan of a PRESAGETM (registered trademark of Heuris Pharma, NJ, Skillman, USA.) dosimeter is given, demonstrating the capabilities of the apparatus.

Image quality assessment and medical physics evaluation of different portable dental X-ray units.

PubMed

Pittayapat, Pisha; Oliveira-Santos, Christiano; Thevissen, Patrick; Michielsen, Koen; Bergans, Niki; Willems, Guy; Debruyckere, Deborah; Jacobs, Reinhilde

2010-09-10

Recently developed portable dental X-ray units increase the mobility of the forensic odontologists and allow more efficient X-ray work in a disaster field, especially when used in combination with digital sensors. This type of machines might also have potential for application in remote areas, military and humanitarian missions, dental care of patients with mobility limitation, as well as imaging in operating rooms. To evaluate radiographic image quality acquired by three portable X-ray devices in combination with four image receptors and to evaluate their medical physics parameters. Images of five samples consisting of four teeth and one formalin-fixed mandible were acquired by one conventional wall-mounted X-ray unit, MinRay 60/70 kVp, used as a clinical standard, and three portable dental X-ray devices: AnyRay 60 kVp, Nomad 60 kVp and Rextar 70 kVp, in combination with a phosphor image plate (PSP), a CCD, or a CMOS sensor. Three observers evaluated images for standard image quality besides forensic diagnostic quality on a 4-point rating scale. Furthermore, all machines underwent tests for occupational as well as patient dosimetry. Statistical analysis showed good quality imaging for all system, with the combination of Nomad and PSP yielding the best score. A significant difference in image quality between the combination of the four X-ray devices and four sensors was established (p<0.05). For patient safety, the exposure rate was determined and exit dose rates for MinRay at 60 kVp, MinRay at 70 kVp, AnyRay, Nomad and Rextar were 3.4 mGy/s, 4.5 mGy/s, 13.5 mGy/s, 3.8 mGy/s and 2.6 mGy/s respectively. The kVp of the AnyRay system was the most stable, with a ripple of 3.7%. Short-term variations in the tube output of all the devices were less than 10%. AnyRay presented higher estimated effective dose than other machines. Occupational dosimetry showed doses at the operator's hand being lowest with protective shielding (Nomad: 0.1 microGy). It was also low while

Optical and dark characterization of the PLATO CCD at ESA

NASA Astrophysics Data System (ADS)

Verhoeve, Peter; Prod'homme, Thibaut; Oosterbroek, Tim; Duvet, Ludovic; Beaufort, Thierry; Blommaert, Sander; Butler, Bart; Heijnen, Jerko; Lemmel, Frederic; van der Luijt, Cornelis; Smit, Hans; Visser, Ivo

2016-07-01

amount of charge lost from a star image are described. These results can serve as a direct input to the PLATO consortium to study the mission performance and as a basis for further optimization of the CCD operation.

Effects of space-radiation damage and temperature on CCD noise for the Lyman FUSE mission

NASA Astrophysics Data System (ADS)

Murowinski, Richard G.; Gao, Linzhuang; Deen, Mohamed J.

1993-09-01

Charge coupled device (CCD) imaging arrays are becoming more frequently used in space vehicles and equipment, especially space-based astronomical telescopes. It is important to understand the effects of radiation on a CCD so that its performance degradation during mission lifetime can be predicted, and so that methods to prevent unacceptable performance degradation can be found. Much recent work by various groups has focused on the problems surrounding the loss of charge transfer efficiency and the increase in dark current and dark current spikes in CCDs. The use of a CCD as the fine error sensor in the Lyman Far Ultraviolet Spectroscopic Explorer (FUSE) is limited by its noise performance. In this work we attempt to understand some of the factors surrounding the noise degradation due to radiation in a space environment. Later, we demonstrate how low frequency noise can be used as a characterization tool for studying proton radiation damage in CCDs.

Vilnius Multicolor CCD Photometry of the Open Cluster NGC 752

NASA Astrophysics Data System (ADS)

Bartašiūtė, S.; Janusz, R.; Boyle, R. P.; Philip, A. G. Davis

We have performed multicolor CCD observations of the central area of NGC 752 to search for faint, low-mass members of this open cluster. Four 12'x12' fields were taken on the 1.8 m Vatican Advanced Technology Telescope (Mt. Graham, Arizona) using a 4K CCD camera and eight intermediate-band filters of the Strömvil system. In this paper we present a catalog of photometry for 405 stars down to the limiting magnitude V=18.5, which contains V magnitudes and color indices of the Vilnius system, together with photometric determinations of spectral types, absolute magnitudes MV, interstellar reddening values EY-V and metallicity parameters [Fe/H]. The good quality multicolor data made it possible to identify the locus of the lower main sequence to four magnitudes beyond the previous (photographic) limit. A relatively small number of photometric members identified at faint magnitudes seems to be indicative of actual dissolution of the cluster from the low-mass end.

CCD filter and transform techniques for interference excision

NASA Technical Reports Server (NTRS)

Borsuk, G. M.; Dewitt, R. N.

1976-01-01

The theoretical and some experimental results of a study aimed at applying CCD filter and transform techniques to the problem of interference excision within communications channels were presented. Adaptive noise (interference) suppression was achieved by the modification of received signals such that they were orthogonal to the recently measured noise field. CCD techniques were examined to develop real-time noise excision processing. They were recursive filters, circulating filter banks, transversal filter banks, an optical implementation of the chirp Z transform, and a CCD analog FFT.

Image quality assessment metric for frame accumulated image

NASA Astrophysics Data System (ADS)

Yu, Jianping; Li, Gang; Wang, Shaohui; Lin, Ling

2018-01-01

The medical image quality determines the accuracy of diagnosis, and the gray-scale resolution is an important parameter to measure image quality. But current objective metrics are not very suitable for assessing medical images obtained by frame accumulation technology. Little attention was paid to the gray-scale resolution, basically based on spatial resolution and limited to the 256 level gray scale of the existing display device. Thus, this paper proposes a metric, "mean signal-to-noise ratio" (MSNR) based on signal-to-noise in order to be more reasonable to evaluate frame accumulated medical image quality. We demonstrate its potential application through a series of images under a constant illumination signal. Here, the mean image of enough images was regarded as the reference image. Several groups of images by different frame accumulation and their MSNR were calculated. The results of the experiment show that, compared with other quality assessment methods, the metric is simpler, more effective, and more suitable for assessing frame accumulated images that surpass the gray scale and precision of the original image.

High-Voltage Clock Driver for Photon-Counting CCD Characterization

NASA Technical Reports Server (NTRS)

Baker, Robert

2013-01-01

A document discusses the CCD97 from e2v technologies as it is being evaluated at Goddard Space Flight Center's Detector Characterization Laboratory (DCL) for possible use in ultra-low background noise space astronomy applications, such as Terrestrial Planet Finder Coronagraph (TPF-C). The CCD97 includes a photoncounting mode where the equivalent output noise is less than one electron. Use of this mode requires a clock signal at a voltage level greater than the level achievable by the existing CCD (charge-coupled-device) electronics. A high-voltage waveform generator has been developed in code 660/601 to support the CCD97 evaluation. The unit generates required clock waveforms at voltage levels from -20 to +50 V. It deals with standard and arbitrary waveforms and supports pixel rates from 50 to 500 kHz. The system is designed to interface with existing Leach CCD electronics.

CCD-camera-based diffuse optical tomography to study ischemic stroke in preclinical rat models

NASA Astrophysics Data System (ADS)

Lin, Zi-Jing; Niu, Haijing; Liu, Yueming; Su, Jianzhong; Liu, Hanli

2011-02-01

Stroke, due to ischemia or hemorrhage, is the neurological deficit of cerebrovasculature and is the third leading cause of death in the United States. More than 80 percent of stroke patients are ischemic stroke due to blockage of artery in the brain by thrombosis or arterial embolism. Hence, development of an imaging technique to image or monitor the cerebral ischemia and effect of anti-stoke therapy is more than necessary. Near infrared (NIR) optical tomographic technique has a great potential to be utilized as a non-invasive image tool (due to its low cost and portability) to image the embedded abnormal tissue, such as a dysfunctional area caused by ischemia. Moreover, NIR tomographic techniques have been successively demonstrated in the studies of cerebro-vascular hemodynamics and brain injury. As compared to a fiberbased diffuse optical tomographic system, a CCD-camera-based system is more suitable for pre-clinical animal studies due to its simpler setup and lower cost. In this study, we have utilized the CCD-camera-based technique to image the embedded inclusions based on tissue-phantom experimental data. Then, we are able to obtain good reconstructed images by two recently developed algorithms: (1) depth compensation algorithm (DCA) and (2) globally convergent method (GCM). In this study, we will demonstrate the volumetric tomographic reconstructed results taken from tissuephantom; the latter has a great potential to determine and monitor the effect of anti-stroke therapies.

A 128K-bit CCD buffer memory system

NASA Technical Reports Server (NTRS)

Siemens, K. H.; Wallace, R. W.; Robinson, C. R.

1976-01-01

A prototype system was implemented to demonstrate that CCD's can be applied advantageously to the problem of low power digital storage and particularly to the problem of interfacing widely varying data rates. 8K-bit CCD shift register memories were used to construct a feasibility model 128K-bit buffer memory system. Peak power dissipation during a data transfer is less than 7 W., while idle power is approximately 5.4 W. The system features automatic data input synchronization with the recirculating CCD memory block start address. Descriptions are provided of both the buffer memory system and a custom tester that was used to exercise the memory. The testing procedures and testing results are discussed. Suggestions are provided for further development with regards to the utilization of advanced versions of CCD memory devices to both simplified and expanded memory system applications.

GEM-based TPC with CCD imaging for directional dark matter detection

NASA Astrophysics Data System (ADS)

Phan, N. S.; Lauer, R. J.; Lee, E. R.; Loomba, D.; Matthews, J. A. J.; Miller, E. H.

2016-11-01

The most mature directional dark matter experiments at present all utilize low-pressure gas Time Projection Chamber (TPC) technologies. We discuss some of the challenges for this technology, for which balancing the goal of achieving the best sensitivity with that of cost effective scale-up requires optimization over a large parameter space. Critical for this are the precision measurements of the fundamental properties of both electron and nuclear recoil tracks down to the lowest detectable energies. Such measurements are necessary to provide a benchmark for background discrimination and directional sensitivity that could be used for future optimization studies for directional dark matter experiments. In this paper we describe a small, high resolution, high signal-to-noise GEM-based TPC with a 2D CCD readout designed for this goal. The performance of the detector was characterized using alpha particles, X-rays, gamma-rays, and neutrons, enabling detailed measurements of electron and nuclear recoil tracks. Stable effective gas gains of greater than 1 × 105 were obtained in 100 Torr of pure CF4 by a cascade of three standard CERN GEMs each with a 140 μm pitch. The high signal-to-noise and sub-millimeter spatial resolution of the GEM amplification and CCD readout, together with low diffusion, allow for excellent background discrimination between electron and nuclear recoils down below ∼10 keVee (∼23 keVr fluorine recoil). Even lower thresholds, necessary for the detection of low mass WIMPs for example, might be achieved by lowering the pressure and utilizing full 3D track reconstruction. These and other paths for improvements are discussed, as are possible fundamental limitations imposed by the physics of energy loss.

CCD Camera Observations

NASA Astrophysics Data System (ADS)

Buchheim, Bob; Argyle, R. W.

One night late in 1918, astronomer William Milburn, observing the region of Cassiopeia from Reverend T.H.E.C. Espin's observatory in Tow Law (England), discovered a hitherto unrecorded double star (Wright 1993). He reported it to Rev. Espin, who measured the pair using his 24-in. reflector: the fainter star was 6.0 arcsec from the primary, at position angle 162.4 ^{circ } (i.e. the fainter star was south-by-southeast from the primary) (Espin 1919). Some time later, it was recognized that the astrograph of the Vatican Observatory had taken an image of the same star-field a dozen years earlier, in late 1906. At that earlier epoch, the fainter star had been separated from the brighter one by only 4.8 arcsec, at position angle 186.2 ^{circ } (i.e. almost due south). Were these stars a binary pair, or were they just two unrelated stars sailing past each other? Some additional measurements might have begun to answer this question. If the secondary star was following a curved path, that would be a clue of orbital motion; if it followed a straight-line path, that would be a clue that these are just two stars passing in the night. Unfortunately, nobody took the trouble to re-examine this pair for almost a century, until the 2MASS astrometric/photometric survey recorded it in late 1998. After almost another decade, this amateur astronomer took some CCD images of the field in 2007, and added another data point on the star's trajectory, as shown in Fig. 15.1.

Measurements of 161 Double Stars With a High-Speed CCD: The Winter/Spring 2017 Observing Program at Brilliant Sky Observatory, Part 2

NASA Astrophysics Data System (ADS)

Harshaw, Richard

2018-04-01

In the winter and spring of 2017, an aggressive observing program of measuring close double stars with speckle interferometry and CCD imaging was undertaken at Brilliant Sky Observatory, my observing site in Cave Creek, Arizona. A total of 596 stars were observed, 8 of which were rejected for various reasons, leaving 588 pairs. Of these, 427 were observed and measured with speckle interferometry, while the remaining 161 were measured with a CCD. This paper reports the results of the observations of the 161 CCD cases. A separate paper in this issue will report the speckle measurements of the 427 other pairs.

Trap pumping schemes for the Euclid CCD273 detector: characterisation of electrodes and defects

NASA Astrophysics Data System (ADS)

Skottfelt, J.; Hall, D. J.; Dryer, B.; Bush, N.; Campa, J.; Gow, J. P. D.; Holland, A. D.; Jordan, D.; Burt, D.

2017-12-01

The VISible imager instrument (VIS) on board the Euclid mission will deliver high resolution shape measurements of galaxies down to very faint limits (R ~ 25 at 10σ) in a large part of the sky, in order to infer the distribution of dark matter in the Universe. To help mitigate radiation damage effects that will accumulate in the detectors over the mission lifetime, the properties of the radiation induced traps needs to be known with as high precision as possible. For this purpose the trap pumping method will be employed as part of the in-orbit calibration routines. Using trap pumping it is possible to identify and characterise single traps in a Charge-Coupled Device (CCD), thus providing information such as the density, emission time constants and sub-pixel positions of the traps in the detectors. This paper presents the trap pumping algorithms used for the radiation testing campaign of the CCD273 detectors, performed by the Centre for Electronic Imaging (CEI) at the Open University, that will be used for the VIS instrument. The CCD273 is a four-phase device with uneven phase widths, which complicates the trap pumping analysis. However, we find that by optimising the trap pumping algorithms and analysis routines, it is possible to obtain sub-pixel and even sub-phase positional information about the traps. Further, by comparing trap pumping data with simulations, it is possible to gain more information about the effective electrode widths of the device.

Investigating the Binary Offset Effect in the STIS CCD

NASA Astrophysics Data System (ADS)

Debes, John H.; Lockwood, Sean A.

2018-05-01

Recently, Boone et al., (2018) presented the "Binary Offset Effect" for the SNIFS instrument, which uses a CCD detector. The source of this uncertainty is related to the analog-to-digital readout process, which converts the analog electronic signal of the detector into a digital number as represented by binary bits. The Binary Offset Effect is due to cross-talk between the digital conversion process for a source or driver pixel and pixels read out after the driver. In the course of Boone et al.'s experimentation with this effect they identified a similar effect with the STIS CCD. The STIS team has independently investigated the Binary Offset Effect for a range of bias images currently used for scientific observations, broadly confirming that the effect exists. However, our preliminary investigation suggests that the impact is smaller than reported in Boone et al. (2018) for biases taken with Amplifier=D and GAIN=1, and a lesser effect exists for Amplifier=D and GAIN=4. There is a hint that the effect is time variable for the detector. We broadly assess the potential impact of this effect and make recommendations both for users and future directions of investigation.

Time-resolved spectra of dense plasma focus using spectrometer, streak camera, and CCD combination.

PubMed

Goldin, F J; Meehan, B T; Hagen, E C; Wilkins, P R

2010-10-01

A time-resolving spectrographic instrument has been assembled with the primary components of a spectrometer, image-converting streak camera, and CCD recording camera, for the primary purpose of diagnosing highly dynamic plasmas. A collection lens defines the sampled region and couples light from the plasma into a step index, multimode fiber which leads to the spectrometer. The output spectrum is focused onto the photocathode of the streak camera, the output of which is proximity-coupled to the CCD. The spectrometer configuration is essentially Czerny-Turner, but off-the-shelf Nikon refraction lenses, rather than mirrors, are used for practicality and flexibility. Only recently assembled, the instrument requires significant refinement, but has now taken data on both bridge wire and dense plasma focus experiments.

Retinal Image Quality During Accommodation

PubMed Central

López-Gil, N.; Martin, J.; Liu, T.; Bradley, A.; Díaz-Muñoz, D.; Thibos, L.

2013-01-01

Purpose We asked if retinal image quality is maximum during accommodation, or sub-optimal due to accommodative error, when subjects perform an acuity task. Methods Subjects viewed a monochromatic (552nm), high-contrast letter target placed at various viewing distances. Wavefront aberrations of the accommodating eye were measured near the endpoint of an acuity staircase paradigm. Refractive state, defined as the optimum target vergence for maximising retinal image quality, was computed by through-focus wavefront analysis to find the power of the virtual correcting lens that maximizes visual Strehl ratio. Results Despite changes in ocular aberrations and pupil size during binocular viewing, retinal image quality and visual acuity typically remain high for all target vergences. When accommodative errors lead to sub-optimal retinal image quality, acuity and measured image quality both decline. However, the effect of accommodation errors of on visual acuity are mitigated by pupillary constriction associated with accommodation and binocular convergence and also to binocular summation of dissimilar retinal image blur. Under monocular viewing conditions some subjects displayed significant accommodative lag that reduced visual performance, an effect that was exacerbated by pharmacological dilation of the pupil. Conclusions Spurious measurement of accommodative error can be avoided when the image quality metric used to determine refractive state is compatible with the focusing criteria used by the visual system to control accommodation. Real focusing errors of the accommodating eye do not necessarily produce a reliably measurable loss of image quality or clinically significant loss of visual performance, probably because of increased depth-of-focus due to pupil constriction. When retinal image quality is close to maximum achievable (given the eye’s higher-order aberrations), acuity is also near maximum. A combination of accommodative lag, reduced image quality, and reduced

Double Star Measurements at the Southern Sky with 50 cm Reflectors and Fast CCD Cameras in 2012

NASA Astrophysics Data System (ADS)

Anton, Rainer

2014-07-01

A Cassegrain and a Ritchey-Chrétien reflector, both with 50 cm aperture, were used in Namibia for recordings of double stars with fast CCD cameras and a notebook computer. From superposition of "lucky images", measurements of 39 double and multiple systems were obtained and compared with literature data. Occasional deviations are discussed. Images of some remarkable systems are also presented.

Application of the CCD Fabry-Perot Annular Summing Technique to Thermospheric O(1)D.

NASA Astrophysics Data System (ADS)

Coakley, Monica Marie

1995-01-01

This work will detail the verification of the advantages of the Fabry-Perot charge coupled device (CCD) annular summing technique, the development of the technique for analysis of daysky spectra, and the implications of the resulting spectra for neutral temperature and wind measurements in the daysky thermosphere. The daysky spectral feature of interest is the bright (1 kilo-Rayleigh) thermospheric (OI) emission at 6300 A which had been observed in the nightsky in order to determine winds and temperatures in the vicinity of the altitude of 250 km. In the daysky, the emission line sits on top of a bright Rayleigh scattered continuum background which significantly complicates the observation. With a triple etalon Fabry-Perot spectrometer, the continuum background can be reduced while maintaining high throughput and high resolution. The inclusion of a CCD camera results in significant savings in integration time over the two more standard scanning photomultiplier systems that have made the same wind and temperature measurements in the past. A comparable CCD system can experience an order of magnitude savings in integration time over a PMT system. Laboratory and field tests which address the advantages and limitations of both the Fabry-Perot CCD annular summing technique and the daysky CCD imaging are included in Chap. 2 and Chap. 3. With a sufficiently large throughput associated with the spectrometer and a CCD detector, rapid observations (~4 minute integrations) can be made. Extraction of the line width and line center from the daysky near-continuum background is complicated compared to the nightsky case, but possible. Methods of fitting the line are included in Chap. 4. The daysky O ^1D temperatures are consistent with a lower average emission height than predicted by models. The data and models are discussed in Chap. 5. Although some discrepancies exist between resulting temperatures and models, the observations indicate the potential for other direct measurements

The research of digital circuit system for high accuracy CCD of portable Raman spectrometer

NASA Astrophysics Data System (ADS)

Yin, Yu; Cui, Yongsheng; Zhang, Xiuda; Yan, Huimin

2013-08-01

The Raman spectrum technology is widely used for it can identify various types of molecular structure and material. The portable Raman spectrometer has become a hot direction of the spectrometer development nowadays for its convenience in handheld operation and real-time detection which is superior to traditional Raman spectrometer with heavy weight and bulky size. But there is still a gap for its measurement sensitivity between portable and traditional devices. However, portable Raman Spectrometer with Shell-Isolated Nanoparticle-Enhanced Raman Spectroscopy (SHINERS) technology can enhance the Raman signal significantly by several orders of magnitude, giving consideration in both measurement sensitivity and mobility. This paper proposed a design and implementation of driver and digital circuit for high accuracy CCD sensor, which is core part of portable spectrometer. The main target of the whole design is to reduce the dark current generation rate and increase signal sensitivity during the long integration time, and in the weak signal environment. In this case, we use back-thinned CCD image sensor from Hamamatsu Corporation with high sensitivity, low noise and large dynamic range. In order to maximize this CCD sensor's performance and minimize the whole size of the device simultaneously to achieve the project indicators, we delicately designed a peripheral circuit for the CCD sensor. The design is mainly composed with multi-voltage circuit, sequential generation circuit, driving circuit and A/D transition parts. As the most important power supply circuit, the multi-voltage circuits with 12 independent voltages are designed with reference power supply IC and set to specified voltage value by the amplifier making up the low-pass filter, which allows the user to obtain a highly stable and accurate voltage with low noise. What's more, to make our design easy to debug, CPLD is selected to generate sequential signal. The A/D converter chip consists of a correlated

JPEG2000 still image coding quality.

PubMed

Chen, Tzong-Jer; Lin, Sheng-Chieh; Lin, You-Chen; Cheng, Ren-Gui; Lin, Li-Hui; Wu, Wei

2013-10-01

This work demonstrates the image qualities between two popular JPEG2000 programs. Two medical image compression algorithms are both coded using JPEG2000, but they are different regarding the interface, convenience, speed of computation, and their characteristic options influenced by the encoder, quantization, tiling, etc. The differences in image quality and compression ratio are also affected by the modality and compression algorithm implementation. Do they provide the same quality? The qualities of compressed medical images from two image compression programs named Apollo and JJ2000 were evaluated extensively using objective metrics. These algorithms were applied to three medical image modalities at various compression ratios ranging from 10:1 to 100:1. Following that, the quality of the reconstructed images was evaluated using five objective metrics. The Spearman rank correlation coefficients were measured under every metric in the two programs. We found that JJ2000 and Apollo exhibited indistinguishable image quality for all images evaluated using the above five metrics (r > 0.98, p < 0.001). It can be concluded that the image quality of the JJ2000 and Apollo algorithms is statistically equivalent for medical image compression.

Update on the Status of the Space Telescope Imaging Spectrograph onboard the Hubble Space Telescope

NASA Astrophysics Data System (ADS)

Hernandez, Svea; Aloisi, A.; Bostroem, K. A.; Cox, C.; Debes, J. H.; DiFelice, A.; Roman-Duval, J.; Hodge, P.; Holland, S.; Lindsay, K.; Lockwood, S. A.; Mason, E.; Oliveira, C. M.; Penton, S. V.; Proffitt, C. R.; Sonnentrucker, P.; Taylor, J. M.; Wheeler, T.

2013-06-01

The Space Telescope Imaging Spectrograph (STIS) has been on orbit for approximately 16 years as one of the 2nd generation instruments on the Hubble Space Telescope (HST). Its operations were interrupted by an electronics failure in 2004, but STIS was successfully repaired in May 2009 during Service Mission 4 (SM4) allowing it to resume science observations. The Instrument team continues to monitor its performance and work towards improving the quality of its products. Here we present updated information on the status of the FUV and NUV MAMA and the CCD detectors onboard STIS and describe recent changes to the STIS calibration pipeline. We also discuss the status of efforts to apply a pixel-based correction for charge transfer inefficiency (CTI) effects to STIS CCD data. These techniques show promise for ameliorating the effects of ongoing radiation damage on the quality of STIS CCD data.

Process perspective on image quality evaluation

NASA Astrophysics Data System (ADS)

Leisti, Tuomas; Halonen, Raisa; Kokkonen, Anna; Weckman, Hanna; Mettänen, Marja; Lensu, Lasse; Ritala, Risto; Oittinen, Pirkko; Nyman, Göte

2008-01-01

The psychological complexity of multivariate image quality evaluation makes it difficult to develop general image quality metrics. Quality evaluation includes several mental processes and ignoring these processes and the use of a few test images can lead to biased results. By using a qualitative/quantitative (Interpretation Based Quality, IBQ) methodology, we examined the process of pair-wise comparison in a setting, where the quality of the images printed by laser printer on different paper grades was evaluated. Test image consisted of a picture of a table covered with several objects. Three other images were also used, photographs of a woman, cityscape and countryside. In addition to the pair-wise comparisons, observers (N=10) were interviewed about the subjective quality attributes they used in making their quality decisions. An examination of the individual pair-wise comparisons revealed serious inconsistencies in observers' evaluations on the test image content, but not on other contexts. The qualitative analysis showed that this inconsistency was due to the observers' focus of attention. The lack of easily recognizable context in the test image may have contributed to this inconsistency. To obtain reliable knowledge of the effect of image context or attention on subjective image quality, a qualitative methodology is needed.

CCD-based vertex detector for ILC

NASA Astrophysics Data System (ADS)

Stefanov, Konstantin D.

2006-12-01

Charge Coupled Devices (CCDs) have been successfully used in several high-energy physics experiments over the last 20 years. Their small pixel size and excellent precision provide a superb tool for studying of short-lived particles and understanding the nature at fundamental level. Over the last few years the Linear Collider Flavour Identification (LCFI) collaboration has developed Column-Parallel CCDs (CPCCD) and CMOS readout chips, to be used for the vertex detector at the International Linear Collider (ILC). The CPCCDs are very fast devices capable of satisfying the challenging requirements imposed by the beam structure of the superconducting accelerator. The first set of prototype devices have been successfully designed, manufactured and tested, with second generation chips on the way. Another idea for CCD-based device, the In-situ Storage Image Sensor (ISIS) is also under development and the first prototype has been manufactured.

Retinal image quality during accommodation.

PubMed

López-Gil, Norberto; Martin, Jesson; Liu, Tao; Bradley, Arthur; Díaz-Muñoz, David; Thibos, Larry N

2013-07-01

We asked if retinal image quality is maximum during accommodation, or sub-optimal due to accommodative error, when subjects perform an acuity task. Subjects viewed a monochromatic (552 nm), high-contrast letter target placed at various viewing distances. Wavefront aberrations of the accommodating eye were measured near the endpoint of an acuity staircase paradigm. Refractive state, defined as the optimum target vergence for maximising retinal image quality, was computed by through-focus wavefront analysis to find the power of the virtual correcting lens that maximizes visual Strehl ratio. Despite changes in ocular aberrations and pupil size during binocular viewing, retinal image quality and visual acuity typically remain high for all target vergences. When accommodative errors lead to sub-optimal retinal image quality, acuity and measured image quality both decline. However, the effect of accommodation errors of on visual acuity are mitigated by pupillary constriction associated with accommodation and binocular convergence and also to binocular summation of dissimilar retinal image blur. Under monocular viewing conditions some subjects displayed significant accommodative lag that reduced visual performance, an effect that was exacerbated by pharmacological dilation of the pupil. Spurious measurement of accommodative error can be avoided when the image quality metric used to determine refractive state is compatible with the focusing criteria used by the visual system to control accommodation. Real focusing errors of the accommodating eye do not necessarily produce a reliably measurable loss of image quality or clinically significant loss of visual performance, probably because of increased depth-of-focus due to pupil constriction. When retinal image quality is close to maximum achievable (given the eye's higher-order aberrations), acuity is also near maximum. A combination of accommodative lag, reduced image quality, and reduced visual function may be a useful

Image quality scaling of electrophotographic prints

NASA Astrophysics Data System (ADS)

Johnson, Garrett M.; Patil, Rohit A.; Montag, Ethan D.; Fairchild, Mark D.

2003-12-01

Two psychophysical experiments were performed scaling overall image quality of black-and-white electrophotographic (EP) images. Six different printers were used to generate the images. There were six different scenes included in the experiment, representing photographs, business graphics, and test-targets. The two experiments were split into a paired-comparison experiment examining overall image quality, and a triad experiment judging overall similarity and dissimilarity of the printed images. The paired-comparison experiment was analyzed using Thurstone's Law, to generate an interval scale of quality, and with dual scaling, to determine the independent dimensions used for categorical scaling. The triad experiment was analyzed using multidimensional scaling to generate a psychological stimulus space. The psychophysical results indicated that the image quality was judged mainly along one dimension and that the relationships among the images can be described with a single dimension in most cases. Regression of various physical measurements of the images to the paired comparison results showed that a small number of physical attributes of the images could be correlated with the psychophysical scale of image quality. However, global image difference metrics did not correlate well with image quality.

[Atmospheric correction of HJ-1 CCD data for water imagery based on dark object model].

PubMed

Zhou, Li-Guo; Ma, Wei-Chun; Gu, Wan-Hua; Huai, Hong-Yan

2011-08-01

The CCD multi-band data of HJ-1A has great potential in inland water quality monitoring, but the precision of atmospheric correction is a premise and necessary procedure for its application. In this paper, a method based on dark pixel for water-leaving radiance retrieving is proposed. Beside the Rayleigh scattering, the aerosol scattering is important to atmospheric correction, the water quality of inland lakes always are case II water and the value of water leaving radiance is not zero. So the synchronous MODIS shortwave infrared data was used to obtain the aerosol parameters, and in virtue of the characteristic that aerosol scattering is relative stabilized in 560 nm, the water-leaving radiance for each visible and near infrared band were retrieved and normalized, accordingly the remotely sensed reflectance of water was computed. The results show that the atmospheric correction method based on the imagery itself is more effective for the retrieval of water parameters for HJ-1A CCD data.

Medición de posiciones astrométricas con CCD en la zona de Rup 21

NASA Astrophysics Data System (ADS)

Bustos Fierro, I. H.; Calderón, J. H.

It is shown the utilization of the block adjustment method for the measurement of astrometric positions from a mosaic of sixteen CCD images with partial overlap, which were taken with the Telescope Jorge Sahade of CASLEO. The observations cover an area of 25' x 25' around the open cluster Rup21. The source of reference positions was ACT Reference Catalog. The internal error of the measured positions is analyzed, and the external error is estimated from the comparison with the catalog USNO-A. In this comparison it is found that the direct CCD images taken with focal reducer could be distorted by severe field curvature. The effect of the distortion presumably introduced by the optics is eliminated with the suitable corrections of the stellar positions measured on every frame, but a new systematic effect on scales of the entire field is observed, which could be due to the distribution of the reference stars.

Image Improvement Techniques

NASA Astrophysics Data System (ADS)

Shine, R. A.

1997-05-01

Over the last decade, a repertoire of techniques have been developed and/or refined to improve the quality of high spatial resolution solar movies taken from ground based observatories. These include real time image motion corrections, frame selection, phase diversity measurements of the wavefront, and extensive post processing to partially remove atmospheric distortion. Their practical application has been made possible by the increasing availability and decreasing cost of large CCD's with fast digital readouts and high speed computer workstations with large memories. Most successful have been broad band (0.3 to 10 nm) filtergram movies which can use exposure times of 10 to 30 ms, short enough to ``freeze'' atmospheric motions. Even so, only a handful of movies with excellent image quality for more than a hour have been obtained to date. Narrowband filtergrams (about 0.01 nm), such as those required for constructing magnetograms and Dopplergrams, have been more challenging although some single images approach the quality of the best continuum images. Some promising new techniques and instruments, together with persistence and good luck, should continue the progress made in the last several years.

Combining HJ CCD, GF-1 WFV and MODIS Data to Generate Daily High Spatial Resolution Synthetic Data for Environmental Process Monitoring.

PubMed

Wu, Mingquan; Huang, Wenjiang; Niu, Zheng; Wang, Changyao

2015-08-20

The limitations of satellite data acquisition mean that there is a lack of satellite data with high spatial and temporal resolutions for environmental process monitoring. In this study, we address this problem by applying the Enhanced Spatial and Temporal Adaptive Reflectance Fusion Model (ESTARFM) and the Spatial and Temporal Data Fusion Approach (STDFA) to combine Huanjing satellite charge coupled device (HJ CCD), Gaofen satellite no. 1 wide field of view camera (GF-1 WFV) and Moderate Resolution Imaging Spectroradiometer (MODIS) data to generate daily high spatial resolution synthetic data for land surface process monitoring. Actual HJ CCD and GF-1 WFV data were used to evaluate the precision of the synthetic images using the correlation analysis method. Our method was tested and validated for two study areas in Xinjiang Province, China. The results show that both the ESTARFM and STDFA can be applied to combine HJ CCD and MODIS reflectance data, and GF-1 WFV and MODIS reflectance data, to generate synthetic HJ CCD data and synthetic GF-1 WFV data that closely match actual data with correlation coefficients (r) greater than 0.8989 and 0.8643, respectively. Synthetic red- and near infrared (NIR)-band data generated by ESTARFM are more suitable for the calculation of Normalized Different Vegetation Index (NDVI) than the data generated by STDFA.

Combining HJ CCD, GF-1 WFV and MODIS Data to Generate Daily High Spatial Resolution Synthetic Data for Environmental Process Monitoring

PubMed Central

Wu, Mingquan; Huang, Wenjiang; Niu, Zheng; Wang, Changyao

2015-01-01

The limitations of satellite data acquisition mean that there is a lack of satellite data with high spatial and temporal resolutions for environmental process monitoring. In this study, we address this problem by applying the Enhanced Spatial and Temporal Adaptive Reflectance Fusion Model (ESTARFM) and the Spatial and Temporal Data Fusion Approach (STDFA) to combine Huanjing satellite charge coupled device (HJ CCD), Gaofen satellite no. 1 wide field of view camera (GF-1 WFV) and Moderate Resolution Imaging Spectroradiometer (MODIS) data to generate daily high spatial resolution synthetic data for land surface process monitoring. Actual HJ CCD and GF-1 WFV data were used to evaluate the precision of the synthetic images using the correlation analysis method. Our method was tested and validated for two study areas in Xinjiang Province, China. The results show that both the ESTARFM and STDFA can be applied to combine HJ CCD and MODIS reflectance data, and GF-1 WFV and MODIS reflectance data, to generate synthetic HJ CCD data and synthetic GF-1 WFV data that closely match actual data with correlation coefficients (r) greater than 0.8989 and 0.8643, respectively. Synthetic red- and near infrared (NIR)-band data generated by ESTARFM are more suitable for the calculation of Normalized Different Vegetation Index (NDVI) than the data generated by STDFA. PMID:26308017

CCD imaging technology and the war on crime

NASA Astrophysics Data System (ADS)

McNeill, Glenn E.

1992-08-01

Linear array based CCD technology has been successfully used in the development of an Automatic Currency Reader/Comparator (ACR/C) system. The ACR/C system is designed to provide a method for tracking US currency in the organized crime and drug trafficking environments where large amounts of cash are involved in illegal transactions and money laundering activities. United States currency notes can be uniquely identified by the combination of the denomination serial number and series year. The ACR/C system processes notes at five notes per second using a custom transport a stationary linear array and optical character recognition (OCR) techniques to make such identifications. In this way large sums of money can be " marked" (using the system to read and store their identifiers) and then circulated within various crime networks. The system can later be used to read and compare confiscated notes to the known sets of identifiers from the " marked" set to document a trail of criminal activities. With the ACR/C law enforcement agencies can efficiently identify currency without actually marking it. This provides an undetectable means for making each note individually traceable and facilitates record keeping for providing evidence in a court of law. In addition when multiple systems are used in conjunction with a central data base the system can be used to track currency geographically. 1.

Test of CCD Precision Limits for Differential Photometry

NASA Technical Reports Server (NTRS)

Borucki, W. J.; Dunham, E. W.; Wei, M. Z.; Robinson, L. B.; Ford, C. H.; Granados, A. F.

1995-01-01

Results of tests to demonstrate the very high differential-photometric stability of CCD light sensors are presented. The measurements reported here demonstrate that in a controlled laboratory environment, a front-illuminated CCD can provide differential-photometric measurements with reproducible precision approaching one part in 105. Practical limitations to the precision of differential-photometric measurements with CCDs and implications for spaceborne applications are discussed.

CCD charge collection efficiency and the photon transfer technique

NASA Technical Reports Server (NTRS)

Janesick, J.; Klaasen, K.; Elliott, T.

1985-01-01

The charge-coupled device (CCD) has shown unprecendented performance as a photon detector in the areas of spectral response, charge transfer, and readout noise. Recent experience indicates, however, that the full potential for the CCD's charge collection efficiency (CCE) lies well beyond that which is realized in currently available devices. A definition of CCE performance is presented and a standard test tool (the photon transfer technique) for measuring and optimizing this important CCD parameter is introduced. CCE characteristics for different types of CCDs are compared; the primary limitations in achieving high CCE performance are discussed, and the prospects for future improvement are outlined.

A wide bandwidth CCD buffer memory system

NASA Technical Reports Server (NTRS)

Siemens, K.; Wallace, R. W.; Robinson, C. R.

1978-01-01

A prototype system was implemented to demonstrate that CCD's can be applied advantageously to the problem of low power digital storage and particularly to the problem of interfacing widely varying data rates. CCD shift register memories (8K bit) were used to construct a feasibility model 128 K-bit buffer memory system. Serial data that can have rates between 150 kHz and 4.0 MHz can be stored in 4K-bit, randomly-accessible memory blocks. Peak power dissipation during a data transfer is less than 7 W, while idle power is approximately 5.4 W. The system features automatic data input synchronization with the recirculating CCD memory block start address. System expansion to accommodate parallel inputs or a greater number of memory blocks can be performed in a modular fashion. Since the control logic does not increase proportionally to increase in memory capacity, the power requirements per bit of storage can be reduced significantly in a larger system.

CICADA, CCD and Instrument Control Software

NASA Astrophysics Data System (ADS)

Young, Peter J.; Brooks, Mick; Meatheringham, Stephen J.; Roberts, William H.

Computerised Instrument Control and Data Acquisition (CICADA) is a software system for control of telescope instruments in a distributed computing environment. It is designed using object-oriented techniques and built with standard computing tools such as RPC, SysV IPC, Posix threads, Tcl, and GUI builders. The system is readily extensible to new instruments and currently supports the Astromed 3200 CCD controller and MSSSO's new tip-tilt system. Work is currently underway to provide support for the SDSU CCD controller and MSSSO's Double Beam Spectrograph. A core set of processes handle common communication and control tasks, while specific instruments are ``bolted'' on using C++ inheritance techniques.

3D digital image correlation using a single 3CCD colour camera and dichroic filter

NASA Astrophysics Data System (ADS)

Zhong, F. Q.; Shao, X. X.; Quan, C.

2018-04-01

In recent years, three-dimensional digital image correlation methods using a single colour camera have been reported. In this study, we propose a simplified system by employing a dichroic filter (DF) to replace the beam splitter and colour filters. The DF can be used to combine two views from different perspectives reflected by two planar mirrors and eliminate their interference. A 3CCD colour camera is then used to capture two different views simultaneously via its blue and red channels. Moreover, the measurement accuracy of the proposed method is higher since the effect of refraction is reduced. Experiments are carried out to verify the effectiveness of the proposed method. It is shown that the interference between the blue and red views is insignificant. In addition, the measurement accuracy of the proposed method is validated on the rigid body displacement. The experimental results demonstrate that the measurement accuracy of the proposed method is higher compared with the reported methods using a single colour camera. Finally, the proposed method is employed to measure the in- and out-of-plane displacements of a loaded plastic board. The re-projection errors of the proposed method are smaller than those of the reported methods using a single colour camera.

Test of CCD Precision Limits for Differential Photometry

NASA Technical Reports Server (NTRS)

Robinson, L. B.; Wei, M. Z.; Borucki, W. J.; Dunham, E. W.; Ford, C. H.; Granados, A. F.

1995-01-01

Results of tests to demonstrate the very high differential-photometric stability of CCD light sensors are presented. The measurements reported here demonstrate that in a controlled laboratory environment, a front-illuminated CCD can provide differential-photometric measurements with reproducible precision approaching one part in 10(exp 5). Practical limitations to the precision of differential-photometric measurements with CCDs and implications for spaceborne applications are discussed.

A Star Image Extractor for Small Satellites

NASA Astrophysics Data System (ADS)

Yamada, Yoshiyuki; Yamauchi, Masahiro; Gouda, Naoteru; Kobayashi, Yukiyasu; Tsujimoto, Takuji; Yano, Taihei; Suganuma, Masahiro; Nakasuka, Shinichi; Sako, Nobutada; Inamori, Takaya

We have developed a Star Image Extractor (SIE) which works as an on-board real-time image processor. It is a logic circuit written on an FPGA(Field Programmable Gate Array) device. It detects and extracts only an object data from raw image data. SIE will be required with the Nano-JASMINE 1) satellite. Nano-JASMINE is the small astrometry satellite that observes objects in our galaxy. It will be launched in 2010 and needs two years mission period. Nano-JASMINE observes an object with the TDI (Time Delayed Integration) observation mode. TDI is one of operation modes of CCD detector. Data is obtained, by rotating the imaging system including CCD at a rated synchronized with a vertical charge transfer of CCD. Obtained image data is sent through SIE to the Mission-controller.

Software design of control system of CCD side-scatter lidar

NASA Astrophysics Data System (ADS)

Kuang, Zhiqiang; Liu, Dong; Deng, Qian; Zhang, Zhanye; Wang, Zhenzhu; Yu, Siqi; Tao, Zongming; Xie, Chenbo; Wang, Yingjian

2018-03-01

Because of the existence of blind zone and transition zone, the application of backscattering lidar in near-ground is limited. The side-scatter lidar equipped with the Charge Coupled Devices (CCD) can separate the transmitting and receiving devices to avoid the impact of the geometric factors which is exited in the backscattering lidar and, detect the more precise near-ground aerosol signals continuously. Theories of CCD side-scatter lidar and the design of control system are introduced. The visible control of laser and CCD and automatic data processing method of the side-scatter lidar are developed by using the software of Visual C #. The results which are compared with the calibration of the atmospheric aerosol lidar data show that signals from the CCD side- scatter lidar are convincible.

Double Star Measurements at the Southern Sky with a 50 cm Reflector and a Fast CCD Camera in 2014

NASA Astrophysics Data System (ADS)

Anton, Rainer

2015-04-01

A Ritchey-Chrétien reflector with 50 cm aperture was used in Namibia for recordings of double stars with a fast CCD camera and a notebook computer. From superposition of "lucky images", measurements of 91 pairings in 79 double and multiple systems were obtained and compared with literature data. Occasional deviations are discussed. Some images of noteworthy systems are also presented.

Assessing product image quality for online shopping

NASA Astrophysics Data System (ADS)

Goswami, Anjan; Chung, Sung H.; Chittar, Naren; Islam, Atiq

2012-01-01

Assessing product-image quality is important in the context of online shopping. A high quality image that conveys more information about a product can boost the buyer's confidence and can get more attention. However, the notion of image quality for product-images is not the same as that in other domains. The perception of quality of product-images depends not only on various photographic quality features but also on various high level features such as clarity of the foreground or goodness of the background etc. In this paper, we define a notion of product-image quality based on various such features. We conduct a crowd-sourced experiment to collect user judgments on thousands of eBay's images. We formulate a multi-class classification problem for modeling image quality by classifying images into good, fair and poor quality based on the guided perceptual notions from the judges. We also conduct experiments with regression using average crowd-sourced human judgments as target. We compute a pseudo-regression score with expected average of predicted classes and also compute a score from the regression technique. We design many experiments with various sampling and voting schemes with crowd-sourced data and construct various experimental image quality models. Most of our models have reasonable accuracies (greater or equal to 70%) on test data set. We observe that our computed image quality score has a high (0.66) rank correlation with average votes from the crowd sourced human judgments.

[NDVI difference rate recognition model of deciduous broad-leaved forest based on HJ-CCD remote sensing data].

PubMed

Wang, Yan; Tian, Qing-Jiu; Huang, Yan; Wei, Hong-Wei

2013-04-01

The present paper takes Chuzhou in Anhui Province as the research area, and deciduous broad-leaved forest as the research object. Then it constructs the recognition model about deciduous broad-leaved forest was constructed using NDVI difference rate between leaf expansion and flowering and fruit-bearing, and the model was applied to HJ-CCD remote sensing image on April 1, 2012 and May 4, 2012. At last, the spatial distribution map of deciduous broad-leaved forest was extracted effectively, and the results of extraction were verified and evaluated. The result shows the validity of NDVI difference rate extraction method proposed in this paper and also verifies the applicability of using HJ-CCD data for vegetation classification and recognition.

Design of system calibration for effective imaging

NASA Astrophysics Data System (ADS)

Varaprasad Babu, G.; Rao, K. M. M.

2006-12-01

A CCD based characterization setup comprising of a light source, CCD linear array, Electronics for signal conditioning/ amplification, PC interface has been developed to generate images at varying densities and at multiple view angles. This arrangement is used to simulate and evaluate images by Super Resolution technique with multiple overlaps and yaw rotated images at different view angles. This setup also generates images at different densities to analyze the response of the detector port wise separately. The light intensity produced by the source needs to be calibrated for proper imaging by the high sensitive CCD detector over the FOV. One approach is to design a complex integrating sphere arrangement which costs higher for such applications. Another approach is to provide a suitable intensity feed back correction wherein the current through the lamp is controlled in a closed loop arrangement. This method is generally used in the applications where the light source is a point source. The third method is to control the time of exposure inversely to the lamp variations where lamp intensity is not possible to control. In this method, light intensity during the start of each line is sampled and the correction factor is applied for the full line. The fourth method is to provide correction through Look Up Table where the response of all the detectors are normalized through the digital transfer function. The fifth method is to have a light line arrangement where the light through multiple fiber optic cables are derived from a single source and arranged them in line. This is generally applicable and economical for low width cases. In our applications, a new method wherein an inverse multi density filter is designed which provides an effective calibration for the full swath even at low light intensities. The light intensity along the length is measured, an inverse density is computed, a correction filter is generated and implemented in the CCD based Characterization

Modular Scanning Confocal Microscope with Digital Image Processing.

PubMed

Ye, Xianjun; McCluskey, Matthew D

2016-01-01

In conventional confocal microscopy, a physical pinhole is placed at the image plane prior to the detector to limit the observation volume. In this work, we present a modular design of a scanning confocal microscope which uses a CCD camera to replace the physical pinhole for materials science applications. Experimental scans were performed on a microscope resolution target, a semiconductor chip carrier, and a piece of etched silicon wafer. The data collected by the CCD were processed to yield images of the specimen. By selecting effective pixels in the recorded CCD images, a virtual pinhole is created. By analyzing the image moments of the imaging data, a lateral resolution enhancement is achieved by using a 20 × / NA = 0.4 microscope objective at 532 nm laser wavelength.

SPECIAL ISSUE ON OPTICAL PROCESSING OF INFORMATION: Optoelectronic processors with scanning CCD photodetectors

NASA Astrophysics Data System (ADS)

Esepkina, N. A.; Lavrov, A. P.; Anan'ev, M. N.; Blagodarnyi, V. S.; Ivanov, S. I.; Mansyrev, M. I.; Molodyakov, S. A.

1995-10-01

Two new types of optoelectronic radio-signal processors were investigated. Charge-coupled device (CCD) photodetectors are used in these processors under continuous scanning conditions, i.e. in a time delay and storage mode. One of these processors is based on a CCD photodetector array with a reference-signal amplitude transparency and the other is an adaptive acousto-optical signal processor with linear frequency modulation. The processor with the transparency performs multichannel discrete—analogue convolution of an input signal with a corresponding kernel of the transformation determined by the transparency. If a light source is an array of light-emitting diodes of special (stripe) geometry, the optical stages of the processor can be made from optical fibre components and the whole processor then becomes a rigid 'sandwich' (a compact hybrid optoelectronic microcircuit). A report is given also of a study of a prototype processor with optical fibre components for the reception of signals from a system with antenna aperture synthesis, which forms a radio image of the Earth.

A CCD search for distant satellites of asteroids 3 Juno and 146 Lucina

NASA Technical Reports Server (NTRS)

Stern, S. Alan; Barker, Edwin S.

1992-01-01

The results of CCD searches for satellites of asteroids 146 Lucina and 3 Juno are reported. Juno is one of the largest asteroids (D = 244 km); no previous deep imaging search for satellites around it has been reported. A potential occultation detection of a small satellite orbiting 146 Lucina (D = 137 km) km was reported by Arlot et al. (1985), but has not been confirmed. Using the 2.1 m reflector at McDonald Observatory in 1990 and 1991 with a CCD camera equipped with a 2.7 arc-sec radius occulting disk, limiting magnitudes of m(sub R) = 19.5 and m(sub R) = 21.4 were achieved around these two asteroids. This corresponds to objects of 1.6 km radius at Juno's albedo and distance, and 0.6 km radius at Lucina's albedo and distance. No satellite detections were made. Unless satellites were located behind our occultation mask, these two asteroids do not have satellites larger than the radii given above.

Double and Multiple Star Measurements at the Southern Sky with a 50cm-Cassegrain and a Fast CCD Camera in 2008

NASA Astrophysics Data System (ADS)

Anton, Rainer

2011-04-01

Using a 50cm Cassegrain in Namibia, recordings of double and multiple stars were made with a fast CCD camera and a notebook computer. From superpositions of "lucky images", measurements of 149 systems were obtained and compared with literature data. B/W and color images of some remarkable systems are also presented.

Securing quality of camera-based biomedical optics

NASA Astrophysics Data System (ADS)

Guse, Frank; Kasper, Axel; Zinter, Bob

2009-02-01

As sophisticated optical imaging technologies move into clinical applications, manufacturers need to guarantee their products meet required performance criteria over long lifetimes and in very different environmental conditions. A consistent quality management marks critical components features derived from end-users requirements in a top-down approach. Careful risk analysis in the design phase defines the sample sizes for production tests, whereas first article inspection assures the reliability of the production processes. We demonstrate the application of these basic quality principles to camera-based biomedical optics for a variety of examples including molecular diagnostics, dental imaging, ophthalmology and digital radiography, covering a wide range of CCD/CMOS chip sizes and resolutions. Novel concepts in fluorescence detection and structured illumination are also highlighted.

Image Quality Ranking Method for Microscopy

PubMed Central

Koho, Sami; Fazeli, Elnaz; Eriksson, John E.; Hänninen, Pekka E.

2016-01-01

Automated analysis of microscope images is necessitated by the increased need for high-resolution follow up of events in time. Manually finding the right images to be analyzed, or eliminated from data analysis are common day-to-day problems in microscopy research today, and the constantly growing size of image datasets does not help the matter. We propose a simple method and a software tool for sorting images within a dataset, according to their relative quality. We demonstrate the applicability of our method in finding good quality images in a STED microscope sample preparation optimization image dataset. The results are validated by comparisons to subjective opinion scores, as well as five state-of-the-art blind image quality assessment methods. We also show how our method can be applied to eliminate useless out-of-focus images in a High-Content-Screening experiment. We further evaluate the ability of our image quality ranking method to detect out-of-focus images, by extensive simulations, and by comparing its performance against previously published, well-established microscopy autofocus metrics. PMID:27364703

Single photon detection imaging of Cherenkov light emitted during radiation therapy

NASA Astrophysics Data System (ADS)

Adamson, Philip M.; Andreozzi, Jacqueline M.; LaRochelle, Ethan; Gladstone, David J.; Pogue, Brian W.

2018-03-01

Cherenkov imaging during radiation therapy has been developed as a tool for dosimetry, which could have applications in patient delivery verification or in regular quality audit. The cameras used are intensified imaging sensors, either ICCD or ICMOS cameras, which allow important features of imaging, including: (1) nanosecond time gating, (2) amplification by 103-104, which together allow for imaging which has (1) real time capture at 10-30 frames per second, (2) sensitivity at the level of single photon event level, and (3) ability to suppress background light from the ambient room. However, the capability to achieve single photon imaging has not been fully analyzed to date, and as such was the focus of this study. The ability to quantitatively characterize how a single photon event appears in amplified camera imaging from the Cherenkov images was analyzed with image processing. The signal seen at normal gain levels appears to be a blur of about 90 counts in the CCD detector, after going through the chain of photocathode detection, amplification through a microchannel plate PMT, excitation onto a phosphor screen and then imaged on the CCD. The analysis of single photon events requires careful interpretation of the fixed pattern noise, statistical quantum noise distributions, and the spatial spread of each pulse through the ICCD.

Colony Collapse Disorder (CCD) and bee age impact honey bee pathophysiology

PubMed Central

Traynor, Kirsten S.; Andree, Michael; Lichtenberg, Elinor M.; Chen, Yanping; Saegerman, Claude; Cox-Foster, Diana L.

2017-01-01

Honey bee (Apis mellifera) colonies continue to experience high annual losses that remain poorly explained. Numerous interacting factors have been linked to colony declines. Understanding the pathways linking pathophysiology with symptoms is an important step in understanding the mechanisms of disease. In this study we examined the specific pathologies associated with honey bees collected from colonies suffering from Colony Collapse Disorder (CCD) and compared these with bees collected from apparently healthy colonies. We identified a set of pathological physical characteristics that occurred at different rates in CCD diagnosed colonies prior to their collapse: rectum distension, Malpighian tubule iridescence, fecal matter consistency, rectal enteroliths (hard concretions), and venom sac color. The multiple differences in rectum symptomology in bees from CCD apiaries and colonies suggest effected bees had trouble regulating water. To ensure that pathologies we found associated with CCD were indeed pathologies and not due to normal changes in physical appearances that occur as an adult bee ages (CCD colonies are assumed to be composed mostly of young bees), we documented the changes in bees of different ages taken from healthy colonies. We found that young bees had much greater incidences of white nodules than older cohorts. Prevalent in newly-emerged bees, these white nodules or cellular encapsulations indicate an active immune response. Comparing the two sets of characteristics, we determined a subset of pathologies that reliably predict CCD status rather than bee age (fecal matter consistency, rectal distension size, rectal enteroliths and Malpighian tubule iridescence) and that may serve as biomarkers for colony health. In addition, these pathologies suggest that CCD bees are experiencing disrupted excretory physiology. Our identification of these symptoms is an important first step in understanding the physiological pathways that underlie CCD and factors

Colony Collapse Disorder (CCD) and bee age impact honey bee pathophysiology.

PubMed

vanEngelsdorp, Dennis; Traynor, Kirsten S; Andree, Michael; Lichtenberg, Elinor M; Chen, Yanping; Saegerman, Claude; Cox-Foster, Diana L

2017-01-01

Honey bee (Apis mellifera) colonies continue to experience high annual losses that remain poorly explained. Numerous interacting factors have been linked to colony declines. Understanding the pathways linking pathophysiology with symptoms is an important step in understanding the mechanisms of disease. In this study we examined the specific pathologies associated with honey bees collected from colonies suffering from Colony Collapse Disorder (CCD) and compared these with bees collected from apparently healthy colonies. We identified a set of pathological physical characteristics that occurred at different rates in CCD diagnosed colonies prior to their collapse: rectum distension, Malpighian tubule iridescence, fecal matter consistency, rectal enteroliths (hard concretions), and venom sac color. The multiple differences in rectum symptomology in bees from CCD apiaries and colonies suggest effected bees had trouble regulating water. To ensure that pathologies we found associated with CCD were indeed pathologies and not due to normal changes in physical appearances that occur as an adult bee ages (CCD colonies are assumed to be composed mostly of young bees), we documented the changes in bees of different ages taken from healthy colonies. We found that young bees had much greater incidences of white nodules than older cohorts. Prevalent in newly-emerged bees, these white nodules or cellular encapsulations indicate an active immune response. Comparing the two sets of characteristics, we determined a subset of pathologies that reliably predict CCD status rather than bee age (fecal matter consistency, rectal distension size, rectal enteroliths and Malpighian tubule iridescence) and that may serve as biomarkers for colony health. In addition, these pathologies suggest that CCD bees are experiencing disrupted excretory physiology. Our identification of these symptoms is an important first step in understanding the physiological pathways that underlie CCD and factors

Comparative Analysis of Reconstructed Image Quality in a Simulated Chromotomographic Imager

DTIC Science & Technology

2014-03-01

quality . This example uses five basic images a backlit bar chart with random intensity, 100 nm separation. A total of 54 initial target...compared for a variety of scenes. Reconstructed image quality is highly dependent on the initial target hypercube so a total of 54 initial target...COMPARATIVE ANALYSIS OF RECONSTRUCTED IMAGE QUALITY IN A SIMULATED CHROMOTOMOGRAPHIC IMAGER THESIS

Global quality imaging: emerging issues.

PubMed

Lau, Lawrence S; Pérez, Maria R; Applegate, Kimberly E; Rehani, Madan M; Ringertz, Hans G; George, Robert

2011-07-01

Quality imaging may be described as "a timely access to and delivery of integrated and appropriate procedures, in a safe and responsive practice, and a prompt delivery of an accurately interpreted report by capable personnel in an efficient, effective, and sustainable manner." For this article, radiation safety is considered as one of the key quality elements. The stakeholders are the drivers of quality imaging. These include those that directly provide or use imaging procedures and others indirectly supporting the system. Imaging is indispensable in health care, and its use has greatly expanded worldwide. Globalization, consumer sophistication, communication and technological advances, corporatization, rationalization, service outsourcing, teleradiology, workflow modularization, and commoditization are reshaping practice. This article defines the emerging issues; an earlier article in the May 2011 issue described possible improvement actions. The issues that could threaten the quality use of imaging for all countries include workforce shortage; increased utilization, population radiation exposure, and cost; practice changes; and efficiency drive and budget constraints. In response to these issues, a range of quality improvement measures, strategies, and actions are used to maximize the benefits and minimize the risks. The 3 measures are procedure justification, optimization of image quality and radiation protection, and error prevention. The development and successful implementation of such improvement actions require leadership, collaboration, and the active participation of all stakeholders to achieve the best outcomes that we all advocate. Copyright © 2011 American College of Radiology. Published by Elsevier Inc. All rights reserved.

Automatic quality assessment of planetary images

NASA Astrophysics Data System (ADS)

Sidiropoulos, P.; Muller, J.-P.

2015-10-01

A significant fraction of planetary images are corrupted beyond the point that much scientific meaning can be extracted. For example, transmission errors result in missing data which is unrecoverable. The available planetary image datasets include many such "bad data", which both occupy valuable scientific storage resources and create false impressions about planetary image availability for specific planetary objects or target areas. In this work, we demonstrate a pipeline that we have developed to automatically assess the quality of planetary images. Additionally, this method discriminates between different types of image degradation, such as low-quality originating from camera flaws or low-quality triggered by atmospheric conditions, etc. Examples of quality assessment results for Viking Orbiter imagery will be also presented.

VizieR Online Data Catalog: Hα images of HD93521 (Rauw+, 2012)

NASA Astrophysics Data System (ADS)

Rauw, G.; Morel, T.; Palate, M.

2012-09-01

The best quality H-alpha images of the field around HD93521 are provided. These data were obtained by amateur astronomer Gaston Dessy (member of the Society Astronomique de Liege, Belgium) with a TMB-92 9.2cm refractor. The first image (haskyco1.fit) was taken with an Atik 16IC CCD and is the combination of 15 individual 5min exposures. The field of view covers 41x30.8-arcmin squared. HD93521 and BD+38 2183 are located on the pixels (328, 230) and (218, 390) respectively. A flat sky background was subtracted. The second image (haskyco2.fit) was taken with an Atik 4000M CCD and is the combination of 12 individual 5min exposures. The field of view covers 127.7x127.7arcmin squared. HD93521 and BD+38 2183 are located on the pixels (1109, 1545) and (989, 1385) respectively. A flat sky background was subtracted. (2 data files).

Night Sky Weather Monitoring System Using Fish-Eye CCD

NASA Astrophysics Data System (ADS)

Tomida, Takayuki; Saito, Yasunori; Nakamura, Ryo; Yamazaki, Katsuya

Telescope Array (TA) is international joint experiment observing ultra-high energy cosmic rays. TA employs fluorescence detection technique to observe cosmic rays. In this technique, tho existence of cloud significantly affects quality of data. Therefore, cloud monitoring provides important information. We are developing two new methods for evaluating night sky weather with pictures taken by charge-coupled device (CCD) camera. One is evaluating the amount of cloud with pixels brightness. The other is counting the number of stars with contour detection technique. The results of these methods show clear correlation, and we concluded both the analyses are reasonable methods for weather monitoring. We discuss reliability of the star counting method.

Guest Editorial Image Quality

NASA Astrophysics Data System (ADS)

Cheatham, Patrick S.

1982-02-01

The term image quality can, unfortunately, apply to anything from a public relations firm's discussion to a comparison between corner drugstores' film processing. If we narrow the discussion to optical systems, we clarify the problem somewhat, but only slightly. We are still faced with a multitude of image quality measures all different, and all couched in different terminology. Optical designers speak of MTF values, digital processors talk about summations of before and after image differences, pattern recognition engineers allude to correlation values, and radar imagers use side-lobe response values measured in decibels. Further complexity is introduced by terms such as information content, bandwidth, Strehl ratios, and, of course, limiting resolution. The problem is to compare these different yardsticks and try to establish some concrete ideas about evaluation of a final image. We need to establish the image attributes which are the most important to perception of the image in question and then begin to apply the different system parameters to those attributes.

Hyper Suprime-Cam: development of the CCD readout electronics

NASA Astrophysics Data System (ADS)

Nakaya, Hidehiko; Uchida, Tomohisa; Miyatake, Hironao; Fujimori, Hiroki; Mineo, Sogo; Aihara, Hiroaki; Furusawa, Hisanori; Kamata, Yukiko; Karoji, Hiroshi; Kawanomoto, Satoshi; Komiyama, Yutaka; Miyazaki, Satoshi; Morokuma, Tomoki; Obuchi, Yoshiyuki; Okura, Yuki; Tanaka, Manobu; Tanaka, Yoko; Uraguchi, Fumihiro; Utsumi, Yosuke

2010-07-01

Hyper Suprime-Cam (HSC) employs 116 of 2k×4k CCDs with 464 signal outputs in total. The image size exceeds 2 GBytes, and the data can be readout every 10 seconds which results in the data rate of 210 Mbytes / sec. The data is digitized to 16-bit. The readout noise of the electronics at the readout time of 20 seconds is ~0.9 ADU, and the one with CCD is ~1.5 ADU which corresponds to ~4.5 e. The linearity error fits within +/- 0.5 % up to 150,000 e. The CCD readout electronics for HSC was newly developed based on the electronics for Suprime-Cam. The frontend electronics (FEE) is placed in the vacuum dewar, and the backend electronics (BEE) is mounted on the outside of the dewar on the prime focus unit. The FEE boards were designed to minimize the outgas and to maximize the heat transfer efficiency to keep the vacuum of the dewar. The BEE boards were designed to be simple and small as long as to achieve the readout time within 10 seconds. The production of the system has been finished, and the full set of the boards are being tested with several CCDs installed in the HSC dewar. We will show the system design, performance, and the current status of the development.

Wide field NEO survey 1.0-m telescope with 10 2k×4k mosaic CCD camera

NASA Astrophysics Data System (ADS)

Isobe, Syuzo; Asami, Atsuo; Asher, David J.; Hashimoto, Toshiyasu; Nakano, Shi-ichi; Nishiyama, Kota; Ohshima, Yoshiaki; Terazono, Junya; Umehara, Hiroaki; Yoshikawa, Makoto

2002-12-01

We developed a new 1.0 m telescope with a 3 degree flat focal plane to which a mosaic CCD camera with 10 2k×4k chips is fixed. The system was set up in February 2002, and is now undergoing the final fine adjustments. Since the telescope has a focal length of 3 m, a field of 7.5 square degrees is covered in one image. In good seeing conditions, 1.5 arc seconds, at the site located in Bisei town, Okayama prefecture in Japan, we can expect to detect down to 20th magnitude stars with an exposure time of 60 seconds. Considering a read-out time, 46 seconds, of the CCD camera, one image is taken in every two minutes, and about 2,100 square degrees of field is expected to be covered in one clear night. This system is very effective for survey work, especially for Near-Earth-Asteroid detection.

Determination of the resolution of a digital system for panoramic radiography based on CCD technology.

PubMed

Mastoris, Mihalis; Li, Gang; Welander, Ulf; McDavid, W D

2004-03-01

To determine Line Spread Functions (LSFs) and Modulation Transfer Functions (MTFs) for a digital system for panoramic radiography: the Dimax I (Planmeca Oy, Helsinki, Finland) based on Charge-Coupled Device (CCD) technology. A test object was specially designed having a gold foil positioned vertically. Images of the gold foil created edge functions that were used to determine LSFs and MTFs. The design of the test object made it possible to move the gold foil forward and backward relative to the central plane of the image layer by means of a micrometer screw. The experiment was carried out for different object depths in 5 different regions: the anterior, the canine, the premolar, the molar, and the TMJ regions. LSFs and MTFs were calculated using specially designed software. The results are presented graphically. LSFs and MTFs for the central plane were essentially the same for all regions. The MTFs for different object depths in the 5 investigated regions exhibited typical characteristics of MTFs for panoramic radiography with the exception for the functions for the molar region. The present findings indicate that the resolution of the Dimax I CCD system is comparable to that of film-based panoramic radiography.

Using a trichromatic CCD camera for spectral skylight estimation.

PubMed

López-Alvarez, Miguel A; Hernández-Andrés, Javier; Romero, Javier; Olmo, F J; Cazorla, A; Alados-Arboledas, L

2008-12-01

In a previous work [J. Opt. Soc. Am. A 24, 942-956 (2007)] we showed how to design an optimum multispectral system aimed at spectral recovery of skylight. Since high-resolution multispectral images of skylight could be interesting for many scientific disciplines, here we also propose a nonoptimum but much cheaper and faster approach to achieve this goal by using a trichromatic RGB charge-coupled device (CCD) digital camera. The camera is attached to a fish-eye lens, hence permitting us to obtain a spectrum of every point of the skydome corresponding to each pixel of the image. In this work we show how to apply multispectral techniques to the sensors' responses of a common trichromatic camera in order to obtain skylight spectra from them. This spectral information is accurate enough to estimate experimental values of some climate parameters or to be used in algorithms for automatic cloud detection, among many other possible scientific applications.

Modular Scanning Confocal Microscope with Digital Image Processing

PubMed Central

McCluskey, Matthew D.

2016-01-01

In conventional confocal microscopy, a physical pinhole is placed at the image plane prior to the detector to limit the observation volume. In this work, we present a modular design of a scanning confocal microscope which uses a CCD camera to replace the physical pinhole for materials science applications. Experimental scans were performed on a microscope resolution target, a semiconductor chip carrier, and a piece of etched silicon wafer. The data collected by the CCD were processed to yield images of the specimen. By selecting effective pixels in the recorded CCD images, a virtual pinhole is created. By analyzing the image moments of the imaging data, a lateral resolution enhancement is achieved by using a 20 × / NA = 0.4 microscope objective at 532 nm laser wavelength. PMID:27829052

Computational polarization difference underwater imaging based on image fusion

NASA Astrophysics Data System (ADS)

Han, Hongwei; Zhang, Xiaohui; Guan, Feng

2016-01-01

Polarization difference imaging can improve the quality of images acquired underwater, whether the background and veiling light are unpolarized or partial polarized. Computational polarization difference imaging technique which replaces the mechanical rotation of polarization analyzer and shortens the time spent to select the optimum orthogonal ǁ and ⊥axes is the improvement of the conventional PDI. But it originally gets the output image by setting the weight coefficient manually to an identical constant for all pixels. In this paper, a kind of algorithm is proposed to combine the Q and U parameters of the Stokes vector through pixel-level image fusion theory based on non-subsample contourlet transform. The experimental system built by the green LED array with polarizer to illuminate a piece of flat target merged in water and the CCD with polarization analyzer to obtain target image under different angle is used to verify the effect of the proposed algorithm. The results showed that the output processed by our algorithm could show more details of the flat target and had higher contrast compared to original computational polarization difference imaging.

Registering coherent change detection products associated with large image sets and long capture intervals

DOEpatents

Perkins, David Nikolaus; Gonzales, Antonio I

2014-04-08

A set of co-registered coherent change detection (CCD) products is produced from a set of temporally separated synthetic aperture radar (SAR) images of a target scene. A plurality of transformations are determined, which transformations are respectively for transforming a plurality of the SAR images to a predetermined image coordinate system. The transformations are used to create, from a set of CCD products produced from the set of SAR images, a corresponding set of co-registered CCD products.

An Underwater Color Image Quality Evaluation Metric.

PubMed

Yang, Miao; Sowmya, Arcot

2015-12-01

Quality evaluation of underwater images is a key goal of underwater video image retrieval and intelligent processing. To date, no metric has been proposed for underwater color image quality evaluation (UCIQE). The special absorption and scattering characteristics of the water medium do not allow direct application of natural color image quality metrics especially to different underwater environments. In this paper, subjective testing for underwater image quality has been organized. The statistical distribution of the underwater image pixels in the CIELab color space related to subjective evaluation indicates the sharpness and colorful factors correlate well with subjective image quality perception. Based on these, a new UCIQE metric, which is a linear combination of chroma, saturation, and contrast, is proposed to quantify the non-uniform color cast, blurring, and low-contrast that characterize underwater engineering and monitoring images. Experiments are conducted to illustrate the performance of the proposed UCIQE metric and its capability to measure the underwater image enhancement results. They show that the proposed metric has comparable performance to the leading natural color image quality metrics and the underwater grayscale image quality metrics available in the literature, and can predict with higher accuracy the relative amount of degradation with similar image content in underwater environments. Importantly, UCIQE is a simple and fast solution for real-time underwater video processing. The effectiveness of the presented measure is also demonstrated by subjective evaluation. The results show better correlation between the UCIQE and the subjective mean opinion score.

Double and Multiple Star Measurements in the Northern Sky with a 10" Newtonian and a Fast CCD Camera in 2006 through 2009

NASA Astrophysics Data System (ADS)

Anton, Rainer

2010-07-01

Using a 10" Newtonian and a fast CCD camera, recordings of double and multiple stars were made at high frame rates with a notebook computer. From superpositions of "lucky images", measurements of 139 systems were obtained and compared with literature data. B/w and color images of some noteworthy systems are also presented.

Blind image quality assessment based on aesthetic and statistical quality-aware features

NASA Astrophysics Data System (ADS)

Jenadeleh, Mohsen; Masaeli, Mohammad Masood; Moghaddam, Mohsen Ebrahimi

2017-07-01

The main goal of image quality assessment (IQA) methods is the emulation of human perceptual image quality judgments. Therefore, the correlation between objective scores of these methods with human perceptual scores is considered as their performance metric. Human judgment of the image quality implicitly includes many factors when assessing perceptual image qualities such as aesthetics, semantics, context, and various types of visual distortions. The main idea of this paper is to use a host of features that are commonly employed in image aesthetics assessment in order to improve blind image quality assessment (BIQA) methods accuracy. We propose an approach that enriches the features of BIQA methods by integrating a host of aesthetics image features with the features of natural image statistics derived from multiple domains. The proposed features have been used for augmenting five different state-of-the-art BIQA methods, which use statistical natural scene statistics features. Experiments were performed on seven benchmark image quality databases. The experimental results showed significant improvement of the accuracy of the methods.

Image quality and dose differences caused by vendor-specific image processing of neonatal radiographs.

PubMed

Sensakovic, William F; O'Dell, M Cody; Letter, Haley; Kohler, Nathan; Rop, Baiywo; Cook, Jane; Logsdon, Gregory; Varich, Laura

2016-10-01

Image processing plays an important role in optimizing image quality and radiation dose in projection radiography. Unfortunately commercial algorithms are black boxes that are often left at or near vendor default settings rather than being optimized. We hypothesize that different commercial image-processing systems, when left at or near default settings, create significant differences in image quality. We further hypothesize that image-quality differences can be exploited to produce images of equivalent quality but lower radiation dose. We used a portable radiography system to acquire images on a neonatal chest phantom and recorded the entrance surface air kerma (ESAK). We applied two image-processing systems (Optima XR220amx, by GE Healthcare, Waukesha, WI; and MUSICA(2) by Agfa HealthCare, Mortsel, Belgium) to the images. Seven observers (attending pediatric radiologists and radiology residents) independently assessed image quality using two methods: rating and matching. Image-quality ratings were independently assessed by each observer on a 10-point scale. Matching consisted of each observer matching GE-processed images and Agfa-processed images with equivalent image quality. A total of 210 rating tasks and 42 matching tasks were performed and effective dose was estimated. Median Agfa-processed image-quality ratings were higher than GE-processed ratings. Non-diagnostic ratings were seen over a wider range of doses for GE-processed images than for Agfa-processed images. During matching tasks, observers matched image quality between GE-processed images and Agfa-processed images acquired at a lower effective dose (11 ± 9 μSv; P < 0.0001). Image-processing methods significantly impact perceived image quality. These image-quality differences can be exploited to alter protocols and produce images of equivalent image quality but lower doses. Those purchasing projection radiography systems or third-party image-processing software should be aware that image

Using a delta-doped CCD to determine the energy of a low-energy particle

NASA Technical Reports Server (NTRS)

Nikzad, Shouleh (Inventor); Croley, Donald R. (Inventor); Murphy, Gerald B. (Inventor)

2001-01-01

The back surface of a thinned charged-coupled device (CCD) is treated to eliminate the backside potential well that appears in a conventional thinned CCD during backside illumination. The backside of the CCD includes a delta layer of high-concentration dopant confined to less than one monolayer of the crystal semiconductor. The thinned, delta-doped CCD is used to determine the energy of a very low-energy particle that penetrates less than 1.0 nm into the CCD, such as a proton having energy less than 10 keV.

Design and implementation of fast bipolar clock drivers for CCD imaging systems in space applications

NASA Astrophysics Data System (ADS)

Jayarajan, Jayesh; Kumar, Nishant; Verma, Amarnath; Thaker, Ramkrishna

2016-05-01

Drive electronics for generating fast, bipolar clocks, which can drive capacitive loads of the order of 5-10nF are indispensable for present day Charge Coupled Devices (CCDs). Design of these high speed bipolar clocks is challenging because of the capacitive loads that have to be driven and a strict constraint on the rise and fall times. Designing drive electronics circuits for space applications becomes even more challenging due to limited number of available discrete devices, which can survive in the harsh radiation prone space environment. This paper presents the design, simulations and test results of a set of such high speed, bipolar clock drivers. The design has been tested under a thermal cycle of -15 deg C to +55 deg C under vacuum conditions and has been designed using radiation hardened components. The test results show that the design meets the stringent rise/fall time requirements of 50+/-10ns for Multiple Vertical CCD (VCCD) clocks and 20+/-5ns for Horizontal CCD (HCCD) clocks with sufficient design margins across full temperature range, with a pixel readout rate of 6.6MHz. The full design has been realized in flexi-rigid PCB with package volume of 140x160x50 mm3.

Optical readout of a two phase liquid argon TPC using CCD camera and THGEMs

NASA Astrophysics Data System (ADS)

Mavrokoridis, K.; Ball, F.; Carroll, J.; Lazos, M.; McCormick, K. J.; Smith, N. A.; Touramanis, C.; Walker, J.

2014-02-01

This paper presents a preliminary study into the use of CCDs to image secondary scintillation light generated by THick Gas Electron Multipliers (THGEMs) in a two phase LAr TPC. A Sony ICX285AL CCD chip was mounted above a double THGEM in the gas phase of a 40 litre two-phase LAr TPC with the majority of the camera electronics positioned externally via a feedthrough. An Am-241 source was mounted on a rotatable motion feedthrough allowing the positioning of the alpha source either inside or outside of the field cage. Developed for and incorporated into the TPC design was a novel high voltage feedthrough featuring LAr insulation. Furthermore, a range of webcams were tested for operation in cryogenics as an internal detector monitoring tool. Of the range of webcams tested the Microsoft HD-3000 (model no:1456) webcam was found to be superior in terms of noise and lowest operating temperature. In ambient temperature and atmospheric pressure 1 ppm pure argon gas, the THGEM gain was ≈ 1000 and using a 1 msec exposure the CCD captured single alpha tracks. Successful operation of the CCD camera in two-phase cryogenic mode was also achieved. Using a 10 sec exposure a photograph of secondary scintillation light induced by the Am-241 source in LAr has been captured for the first time.

Image quality assessment using deep convolutional networks

NASA Astrophysics Data System (ADS)

Li, Yezhou; Ye, Xiang; Li, Yong

2017-12-01

This paper proposes a method of accurately assessing image quality without a reference image by using a deep convolutional neural network. Existing training based methods usually utilize a compact set of linear filters for learning features of images captured by different sensors to assess their quality. These methods may not be able to learn the semantic features that are intimately related with the features used in human subject assessment. Observing this drawback, this work proposes training a deep convolutional neural network (CNN) with labelled images for image quality assessment. The ReLU in the CNN allows non-linear transformations for extracting high-level image features, providing a more reliable assessment of image quality than linear filters. To enable the neural network to take images of any arbitrary size as input, the spatial pyramid pooling (SPP) is introduced connecting the top convolutional layer and the fully-connected layer. In addition, the SPP makes the CNN robust to object deformations to a certain extent. The proposed method taking an image as input carries out an end-to-end learning process, and outputs the quality of the image. It is tested on public datasets. Experimental results show that it outperforms existing methods by a large margin and can accurately assess the image quality on images taken by different sensors of varying sizes.

Quantification of in vitro produced wear sites on composite resins using contact profilometry and CCD microscopy: a methodological investigation.

PubMed

Koottathape, Natthavoot; Takahashi, Hidekazu; Finger, Wernerj; Kanehira, Masafumi; Iwasaki, Naohiko; Aoyagi, Yujin

2012-06-01

Although attritive and abrasive wear of recent composite resins has been substantially reduced, in vitro wear testing with reasonably simulating devices and quantitative determination of resulting wear is still needed. Three-dimensional scanning methods are frequently used for this purpose. The aim of this trial was to compare maximum depth of wear and volume loss of composite samples, evaluated with a contact profilometer and a non-contact CCD camera imaging system, respectively. Twenty-three random composite specimens with wear traces produced in a ball-on-disc sliding device, using poppy seed slurry and PMMA suspension as third-body media, were evaluated with the contact profilometer (TalyScan 150, Taylor Hobson LTD, Leicester, UK) and with the digital CCD microscope (VHX1000, KEYENCE, Osaka, Japan). The target parameters were maximum depth of the wear and volume loss.Results - The individual time of measurement needed with the non-contact CCD method was almost three hours less than that with the contact method. Both, maximum depth of wear and volume loss data, recorded with the two methods were linearly correlated (r(2) > 0.97; p < 0.01). The contact scanning method and the non-contact CCD method are equally suitable for determination of maximum depth of wear and volume loss of abraded composite resins.

Design and Development of Multi-Purpose CCD Camera System with Thermoelectric Cooling: Hardware

NASA Astrophysics Data System (ADS)

Kang, Y.-W.; Byun, Y. I.; Rhee, J. H.; Oh, S. H.; Kim, D. K.

2007-12-01

We designed and developed a multi-purpose CCD camera system for three kinds of CCDs; KAF-0401E(768×512), KAF-1602E(1536×1024), KAF-3200E(2184×1472) made by KODAK Co.. The system supports fast USB port as well as parallel port for data I/O and control signal. The packing is based on two stage circuit boards for size reduction and contains built-in filter wheel. Basic hardware components include clock pattern circuit, A/D conversion circuit, CCD data flow control circuit, and CCD temperature control unit. The CCD temperature can be controlled with accuracy of approximately 0.4° C in the max. range of temperature, Δ 33° C. This CCD camera system has with readout noise 6 e^{-}, and system gain 5 e^{-}/ADU. A total of 10 CCD camera systems were produced and our tests show that all of them show passable performance.

The study of surgical image quality evaluation system by subjective quality factor method

NASA Astrophysics Data System (ADS)

Zhang, Jian J.; Xuan, Jason R.; Yang, Xirong; Yu, Honggang; Koullick, Edouard

2016-03-01

GreenLightTM procedure is an effective and economical way of treatment of benign prostate hyperplasia (BPH); there are almost a million of patients treated with GreenLightTM worldwide. During the surgical procedure, the surgeon or physician will rely on the monitoring video system to survey and confirm the surgical progress. There are a few obstructions that could greatly affect the image quality of the monitoring video, like laser glare by the tissue and body fluid, air bubbles and debris generated by tissue evaporation, and bleeding, just to name a few. In order to improve the physician's visual experience of a laser surgical procedure, the system performance parameter related to image quality needs to be well defined. However, since image quality is the integrated set of perceptions of the overall degree of excellence of an image, or in other words, image quality is the perceptually weighted combination of significant attributes (contrast, graininess …) of an image when considered in its marketplace or application, there is no standard definition on overall image or video quality especially for the no-reference case (without a standard chart as reference). In this study, Subjective Quality Factor (SQF) and acutance are used for no-reference image quality evaluation. Basic image quality parameters, like sharpness, color accuracy, size of obstruction and transmission of obstruction, are used as subparameter to define the rating scale for image quality evaluation or comparison. Sample image groups were evaluated by human observers according to the rating scale. Surveys of physician groups were also conducted with lab generated sample videos. The study shows that human subjective perception is a trustworthy way of image quality evaluation. More systematic investigation on the relationship between video quality and image quality of each frame will be conducted as a future study.

Modified-BRISQUE as no reference image quality assessment for structural MR images.

PubMed

Chow, Li Sze; Rajagopal, Heshalini

2017-11-01

An effective and practical Image Quality Assessment (IQA) model is needed to assess the image quality produced from any new hardware or software in MRI. A highly competitive No Reference - IQA (NR - IQA) model called Blind/Referenceless Image Spatial Quality Evaluator (BRISQUE) initially designed for natural images were modified to evaluate structural MR images. The BRISQUE model measures the image quality by using the locally normalized luminance coefficients, which were used to calculate the image features. The modified-BRISQUE model trained a new regression model using MR image features and Difference Mean Opinion Score (DMOS) from 775 MR images. Two types of benchmarks: objective and subjective assessments were used as performance evaluators for both original and modified-BRISQUE models. There was a high correlation between the modified-BRISQUE with both benchmarks, and they were higher than those for the original BRISQUE. There was a significant percentage improvement in their correlation values. The modified-BRISQUE was statistically better than the original BRISQUE. The modified-BRISQUE model can accurately measure the image quality of MR images. It is a practical NR-IQA model for MR images without using reference images. Copyright © 2017 Elsevier Inc. All rights reserved.

LED characterization for development of on-board calibration unit of CCD-based advanced wide-field sensor camera of Resourcesat-2A

NASA Astrophysics Data System (ADS)

Chatterjee, Abhijit; Verma, Anurag

2016-05-01

The Advanced Wide Field Sensor (AWiFS) camera caters to high temporal resolution requirement of Resourcesat-2A mission with repeativity of 5 days. The AWiFS camera consists of four spectral bands, three in the visible and near IR and one in the short wave infrared. The imaging concept in VNIR bands is based on push broom scanning that uses linear array silicon charge coupled device (CCD) based Focal Plane Array (FPA). On-Board Calibration unit for these CCD based FPAs is used to monitor any degradation in FPA during entire mission life. Four LEDs are operated in constant current mode and 16 different light intensity levels are generated by electronically changing exposure of CCD throughout the calibration cycle. This paper describes experimental setup and characterization results of various flight model visible LEDs (λP=650nm) for development of On-Board Calibration unit of Advanced Wide Field Sensor (AWiFS) camera of RESOURCESAT-2A. Various LED configurations have been studied to meet dynamic range coverage of 6000 pixels silicon CCD based focal plane array from 20% to 60% of saturation during night pass of the satellite to identify degradation of detector elements. The paper also explains comparison of simulation and experimental results of CCD output profile at different LED combinations in constant current mode.

6 x 6-cm fully depleted pn-junction CCD for high-resolution spectroscopy in the 0.1- to 15-keV photon energy range

NASA Astrophysics Data System (ADS)

von Zanthier, Christoph; Holl, Peter; Kemmer, Josef; Lechner, Peter; Maier, B.; Soltau, Heike; Stoetter, R.; Braeuninger, Heinrich W.; Dennerl, Konrad; Haberl, Frank; Hartmann, R.; Hartner, Gisela D.; Hippmann, H.; Kastelic, E.; Kink, W.; Krause, N.; Meidinger, Norbert; Metzner, G.; Pfeffermann, Elmar; Popp, M.; Reppin, Claus; Stoetter, Diana; Strueder, Lothar; Truemper, Joachim; Weber, U.; Carathanassis, D.; Engelhard, S.; Gebhart, Th.; Hauff, D.; Lutz, G.; Richter, R. H.; Seitz, H.; Solc, P.; Bihler, Edgar; Boettcher, H.; Kendziorra, Eckhard; Kraemer, J.; Pflueger, Bernhard; Staubert, Ruediger

1998-04-01

The concept and performance of the fully depleted pn- junction CCD system, developed for the European XMM- and the German ABRIXAS-satellite missions for soft x-ray imaging and spectroscopy in the 0.1 keV to 15 keV photon range, is presented. The 58 mm X 60 mm large pn-CCD array uses pn- junctions for registers and for the backside instead of MOS registers. This concept naturally allows to fully deplete the detector volume to make it an efficient detector to photons with energies up to 15 keV. For high detection efficiency in the soft x-ray region down to 100 eV, an ultrathin pn-CCD backside deadlayer has been realized. Each pn-CCD-channel is equipped with an on-chip JFET amplifier which, in combination with the CAMEX-amplifier and multiplexing chip, facilitates parallel readout with a pixel read rate of 3 MHz and an electronic noise floor of ENC < e-. With the complete parallel readout, very fast pn-CCD readout modi can be implemented in the system which allow for high resolution photon spectroscopy of even the brightest x-ray sources in the sky.

Measuring the effective pixel positions for the HARPS3 CCD

NASA Astrophysics Data System (ADS)

Hall, Richard D.; Thompson, Samantha; Queloz, Didier

2016-07-01

We present preliminary results from an experiment designed to measure the effective pixel positions of a CCD to sub-pixel precision. This technique will be used to characterise the 4k x 4k CCD destined for the HARPS-3 spectrograph. The principle of coherent beam interference is used to create intensity fringes along one axis of the CCD. By sweeping the physical parameters of the experiment, the geometry of the fringes can be altered which is used to probe the pixel structure. We also present the limitations of the current experimental set-up and suggest what will be implemented in the future to vastly improve the precision of the measurements.

Quantitative image quality evaluation of MR images using perceptual difference models

PubMed Central

Miao, Jun; Huo, Donglai; Wilson, David L.

2008-01-01

The authors are using a perceptual difference model (Case-PDM) to quantitatively evaluate image quality of the thousands of test images which can be created when optimizing fast magnetic resonance (MR) imaging strategies and reconstruction techniques. In this validation study, they compared human evaluation of MR images from multiple organs and from multiple image reconstruction algorithms to Case-PDM and similar models. The authors found that Case-PDM compared very favorably to human observers in double-stimulus continuous-quality scale and functional measurement theory studies over a large range of image quality. The Case-PDM threshold for nonperceptible differences in a 2-alternative forced choice study varied with the type of image under study, but was ≈1.1 for diffuse image effects, providing a rule of thumb. Ordering the image quality evaluation models, we found in overall Case-PDM ≈ IDM (Sarnoff Corporation) ≈ SSIM [Wang et al. IEEE Trans. Image Process. 13, 600–612 (2004)] > mean squared error ≈ NR [Wang et al. (2004) (unpublished)] > DCTune (NASA) > IQM (MITRE Corporation). The authors conclude that Case-PDM is very useful in MR image evaluation but that one should probably restrict studies to similar images and similar processing, normally not a limitation in image reconstruction studies. PMID:18649487

The design and realization of a three-dimensional video system by means of a CCD array

NASA Astrophysics Data System (ADS)

Boizard, J. L.

1985-12-01

Design features and principles and initial tests of a prototype three-dimensional robot vision system based on a laser source and a CCD detector array is described. The use of a laser as a coherent illumination source permits the determination of the relief using one emitter since the location of the source is a known quantity with low distortion. The CCD signal detector array furnishes an acceptable signal/noise ratio and, when wired to an appropriate signal processing system, furnishes real-time data on the return signals, i.e., the characteristic points of an object being scanned. Signal processing involves integration of 29 kB of data per 100 samples, with sampling occurring at a rate of 5 MHz (the CCDs) and yielding an image every 12 msec. Algorithms for filtering errors from the data stream are discussed.

Specialized CCDs for high-frame-rate visible imaging and UV imaging applications

NASA Astrophysics Data System (ADS)

Levine, Peter A.; Taylor, Gordon C.; Shallcross, Frank V.; Tower, John R.; Lawler, William B.; Harrison, Lorna J.; Socker, Dennis G.; Marchywka, Mike

1993-11-01

This paper reports recent progress by the authors in two distinct charge coupled device (CCD) technology areas. The first technology area is high frame rate, multi-port, frame transfer imagers. A 16-port, 512 X 512, split frame transfer imager and a 32-port, 1024 X 1024, split frame transfer imager are described. The thinned, backside illuminated devices feature on-chip correlated double sampling, buried blooming drains, and a room temperature dark current of less than 50 pA/cm2, without surface accumulation. The second technology area is vacuum ultraviolet (UV) frame transfer imagers. A developmental 1024 X 640 frame transfer imager with 20% quantum efficiency at 140 nm is described. The device is fabricated in a p-channel CCD process, thinned for backside illumination, and utilizes special packaging to achieve stable UV response.

Retinal image quality assessment based on image clarity and content

NASA Astrophysics Data System (ADS)

Abdel-Hamid, Lamiaa; El-Rafei, Ahmed; El-Ramly, Salwa; Michelson, Georg; Hornegger, Joachim

2016-09-01

Retinal image quality assessment (RIQA) is an essential step in automated screening systems to avoid misdiagnosis caused by processing poor quality retinal images. A no-reference transform-based RIQA algorithm is introduced that assesses images based on five clarity and content quality issues: sharpness, illumination, homogeneity, field definition, and content. Transform-based RIQA algorithms have the advantage of considering retinal structures while being computationally inexpensive. Wavelet-based features are proposed to evaluate the sharpness and overall illumination of the images. A retinal saturation channel is designed and used along with wavelet-based features for homogeneity assessment. The presented sharpness and illumination features are utilized to assure adequate field definition, whereas color information is used to exclude nonretinal images. Several publicly available datasets of varying quality grades are utilized to evaluate the feature sets resulting in area under the receiver operating characteristic curve above 0.99 for each of the individual feature sets. The overall quality is assessed by a classifier that uses the collective features as an input vector. The classification results show superior performance of the algorithm in comparison to other methods from literature. Moreover, the algorithm addresses efficiently and comprehensively various quality issues and is suitable for automatic screening systems.

Remote Sensing Image Quality Assessment Experiment with Post-Processing

NASA Astrophysics Data System (ADS)

Jiang, W.; Chen, S.; Wang, X.; Huang, Q.; Shi, H.; Man, Y.

2018-04-01

This paper briefly describes the post-processing influence assessment experiment, the experiment includes three steps: the physical simulation, image processing, and image quality assessment. The physical simulation models sampled imaging system in laboratory, the imaging system parameters are tested, the digital image serving as image processing input are produced by this imaging system with the same imaging system parameters. The gathered optical sampled images with the tested imaging parameters are processed by 3 digital image processes, including calibration pre-processing, lossy compression with different compression ratio and image post-processing with different core. Image quality assessment method used is just noticeable difference (JND) subject assessment based on ISO20462, through subject assessment of the gathered and processing images, the influence of different imaging parameters and post-processing to image quality can be found. The six JND subject assessment experimental data can be validated each other. Main conclusions include: image post-processing can improve image quality; image post-processing can improve image quality even with lossy compression, image quality with higher compression ratio improves less than lower ratio; with our image post-processing method, image quality is better, when camera MTF being within a small range.

High resolution biomedical imaging system with direct detection of x-rays via a charge coupled device

DOEpatents

Atac, M.; McKay, T.A.

1998-04-21

An imaging system is provided for direct detection of x-rays from an irradiated biological tissue. The imaging system includes an energy source for emitting x-rays toward the biological tissue and a charge coupled device (CCD) located immediately adjacent the biological tissue and arranged transverse to the direction of irradiation along which the x-rays travel. The CCD directly receives and detects the x-rays after passing through the biological tissue. The CCD is divided into a matrix of cells, each of which individually stores a count of x-rays directly detected by the cell. The imaging system further includes a pattern generator electrically coupled to the CCD for reading a count from each cell. A display device is provided for displaying an image representative of the count read by the pattern generator from the cells of the CCD. 13 figs.

High resolution biomedical imaging system with direct detection of x-rays via a charge coupled device

DOEpatents

Atac, Muzaffer; McKay, Timothy A.

1998-01-01

An imaging system is provided for direct detection of x-rays from an irradiated biological tissue. The imaging system includes an energy source for emitting x-rays toward the biological tissue and a charge coupled device (CCD) located immediately adjacent the biological tissue and arranged transverse to the direction of irradiation along which the x-rays travel. The CCD directly receives and detects the x-rays after passing through the biological tissue. The CCD is divided into a matrix of cells, each of which individually stores a count of x-rays directly detected by the cell. The imaging system further includes a pattern generator electrically coupled to the CCD for reading a count from each cell. A display device is provided for displaying an image representative of the count read by the pattern generator from the cells of the CCD.

Subjective matters: from image quality to image psychology

NASA Astrophysics Data System (ADS)

Fedorovskaya, Elena A.; De Ridder, Huib

2013-03-01

From the advent of digital imaging through several decades of studies, the human vision research community systematically focused on perceived image quality and digital artifacts due to resolution, compression, gamma, dynamic range, capture and reproduction noise, blur, etc., to help overcome existing technological challenges and shortcomings. Technological advances made digital images and digital multimedia nearly flawless in quality, and ubiquitous and pervasive in usage, provide us with the exciting but at the same time demanding possibility to turn to the domain of human experience including higher psychological functions, such as cognition, emotion, awareness, social interaction, consciousness and Self. In this paper we will outline the evolution of human centered multidisciplinary studies related to imaging and propose steps and potential foci of future research.

Noise analysis for CCD-based ultraviolet and visible spectrophotometry.

PubMed

Davenport, John J; Hodgkinson, Jane; Saffell, John R; Tatam, Ralph P

2015-09-20

We present the results of a detailed analysis of the noise behavior of two CCD spectrometers in common use, an AvaSpec-3648 CCD UV spectrometer and an Ocean Optics S2000 Vis spectrometer. Light sources used include a deuterium UV/Vis lamp and UV and visible LEDs. Common noise phenomena include source fluctuation noise, photoresponse nonuniformity, dark current noise, fixed pattern noise, and read noise. These were identified and characterized by varying light source, spectrometer settings, or temperature. A number of noise-limiting techniques are proposed, demonstrating a best-case spectroscopic noise equivalent absorbance of 3.5×10(-4)  AU for the AvaSpec-3648 and 5.6×10(-4)  AU for the Ocean Optics S2000 over a 30 s integration period. These techniques can be used on other CCD spectrometers to optimize performance.

CCD astrometric observations of Saturnian satellites

NASA Astrophysics Data System (ADS)

Veiga, C. H.; Vieira Martins, R.; Vienne, A.; Thuillot, W.; Arlot, J.-E.

2003-03-01

Astrometric positions of the first eight largest Saturnian satellites and the Lagrangian satellites Helene, Telesto and Calypso are presented from 493 CCD frames taken at the oppositions in 1995 through 1999. The images were obtained over 27 nights. Observed positions are compared with the calculated ones from Vienne and Duriez TASS 1.7 for the large satellites and from JPL positions for the Lagrangian satellites. The rms is about 0farcs 12 for the former but 0farcs 20 for Iapetus and 0farcs 28 for Hyperion. For the Lagrangian satellites it is about 0farcs 21 for Helene, 2farcs 02 for Telesto and 0farcs 60 for Calypso. The catalog (Full Table \\ref{tab4}) is only available in electronic form at the CDS via anonymous ftp to cdsarc.u-strasbg.fr (130.79.128.5) or via http://cdsweb.u-strasbg.fr/cgi-bin/qcat?J/A+A/400/1095 Based on observations made at Laboratório Nacional de Astrofísica/MCT-Itajubá-Brazil.

Feature maps driven no-reference image quality prediction of authentically distorted images

NASA Astrophysics Data System (ADS)

Ghadiyaram, Deepti; Bovik, Alan C.

2015-03-01

Current blind image quality prediction models rely on benchmark databases comprised of singly and synthetically distorted images, thereby learning image features that are only adequate to predict human perceived visual quality on such inauthentic distortions. However, real world images often contain complex mixtures of multiple distortions. Rather than a) discounting the effect of these mixtures of distortions on an image's perceptual quality and considering only the dominant distortion or b) using features that are only proven to be efficient for singly distorted images, we deeply study the natural scene statistics of authentically distorted images, in different color spaces and transform domains. We propose a feature-maps-driven statistical approach which avoids any latent assumptions about the type of distortion(s) contained in an image, and focuses instead on modeling the remarkable consistencies in the scene statistics of real world images in the absence of distortions. We design a deep belief network that takes model-based statistical image features derived from a very large database of authentically distorted images as input and discovers good feature representations by generalizing over different distortion types, mixtures, and severities, which are later used to learn a regressor for quality prediction. We demonstrate the remarkable competence of our features for improving automatic perceptual quality prediction on a benchmark database and on the newly designed LIVE Authentic Image Quality Challenge Database and show that our approach of combining robust statistical features and the deep belief network dramatically outperforms the state-of-the-art.

Exploration of multidimensional interactive classroom teaching for CCD principle and application course

NASA Astrophysics Data System (ADS)

Fu, Xinghu; Tan, Ailing; Zhang, Baojun; Fu, Guangwei; Bi, Weihong

2017-08-01

The CCD principle and application course is professional and comprehensive. It involves many subject contents. The course content includes eight aspects. In order to complete the teaching tasks within a limited time, improve the classroom teaching quality and prompt students master the course content faster and better, so the multidimensional interactive classroom teaching is proposed. In the teaching practice, the interactive relationship between the frontier science, scientific research project, living example and classroom content is researched detailedly. Finally, it has been proved practically that the proposed multidimensional interactive classroom teaching can achieved good teaching effect.

Modelling electron distributions within ESA's Gaia satellite CCD pixels to mitigate radiation damage

NASA Astrophysics Data System (ADS)

Seabroke, G. M.; Holland, A. D.; Burt, D.; Robbins, M. S.

2009-08-01

The Gaia satellite is a high-precision astrometry, photometry and spectroscopic ESA cornerstone mission, currently scheduled for launch in 2012. Its primary science drivers are the composition, formation and evolution of the Galaxy. Gaia will achieve its unprecedented positional accuracy requirements with detailed calibration and correction for radiation damage. At L2, protons cause displacement damage in the silicon of CCDs. The resulting traps capture and emit electrons from passing charge packets in the CCD pixel, distorting the image PSF and biasing its centroid. Microscopic models of Gaia's CCDs are being developed to simulate this effect. The key to calculating the probability of an electron being captured by a trap is the 3D electron density within each CCD pixel. However, this has not been physically modelled for the Gaia CCD pixels. In Seabroke, Holland & Cropper (2008), the first paper of this series, we motivated the need for such specialised 3D device modelling and outlined how its future results will fit into Gaia's overall radiation calibration strategy. In this paper, the second of the series, we present our first results using Silvaco's physics-based, engineering software: the ATLAS device simulation framework. Inputting a doping profile, pixel geometry and materials into ATLAS and comparing the results to other simulations reveals that ATLAS has a free parameter, fixed oxide charge, that needs to be calibrated. ATLAS is successfully benchmarked against other simulations and measurements of a test device, identifying how to use it to model Gaia pixels and highlighting the affect of different doping approximations.

Asteroid detection using a single multi-wavelength CCD scan

NASA Astrophysics Data System (ADS)

Melton, Jonathan

2016-09-01

Asteroid detection is a topic of great interest due to the possibility of diverting possibly dangerous asteroids or mining potentially lucrative ones. Currently, asteroid detection is generally performed by taking multiple images of the same patch of sky separated by 10-15 minutes, then subtracting the images to find movement. However, this is time consuming because of the need to revisit the same area multiple times per night. This paper describes an algorithm that can detect asteroids using a single CCD camera scan, thus cutting down on the time and cost of an asteroid survey. The algorithm is based on the fact that some telescopes scan the sky at multiple wavelengths with a small time separation between the wavelength components. As a result, an object moving with sufficient speed will appear in different places in different wavelength components of the same image. Using image processing techniques we detect the centroids of points of light in the first component and compare these positions to the centroids in the other components using a nearest neighbor algorithm. The algorithm was used on a test set of 49 images obtained from the Sloan telescope in New Mexico and found 100% of known asteroids with only 3 false positives. This algorithm has the advantage of decreasing the amount of time required to perform an asteroid scan, thus allowing more sky to be scanned in the same amount of time or freeing a telescope for other pursuits.

Objective quality assessment for multiexposure multifocus image fusion.

PubMed

Hassen, Rania; Wang, Zhou; Salama, Magdy M A

2015-09-01

There has been a growing interest in image fusion technologies, but how to objectively evaluate the quality of fused images has not been fully understood. Here, we propose a method for objective quality assessment of multiexposure multifocus image fusion based on the evaluation of three key factors of fused image quality: 1) contrast preservation; 2) sharpness; and 3) structure preservation. Subjective experiments are conducted to create an image fusion database, based on which, performance evaluation shows that the proposed fusion quality index correlates well with subjective scores, and gives a significant improvement over the existing fusion quality measures.

No-reference image quality assessment for horizontal-path imaging scenarios

NASA Astrophysics Data System (ADS)

Rios, Carlos; Gladysz, Szymon

2013-05-01

There exist several image-enhancement algorithms and tasks associated with imaging through turbulence that depend on defining the quality of an image. Examples include: "lucky imaging", choosing the width of the inverse filter for image reconstruction, or stopping iterative deconvolution. We collected a number of image quality metrics found in the literature. Particularly interesting are the blind, "no-reference" metrics. We discuss ways of evaluating the usefulness of these metrics, even when a fully objective comparison is impossible because of the lack of a reference image. Metrics are tested on simulated and real data. Field data comes from experiments performed by the NATO SET 165 research group over a 7 km distance in Dayton, Ohio.

A CCD-based search for very low mass members of the Pleiades cluster

NASA Technical Reports Server (NTRS)

Stauffer, John R.; Hamilton, Donald; Probst, Ronald G.

1994-01-01

We have obtained deep charge coupled device (CCD)V and I images of a number of fields near the center of the Pleiades open cluster. We have also obtained imaging data for Praesepe, a very similar cluster in terms of distance and richness but nearly 10 times older than the Pleiades. Because brown dwarfs are predicted to become much fainter and cooler between Pleiades and Praesepe ages, this provides a powerful differential technique for placing constraints on the brown dwarf population in open clusters. Combined with our previously reported observations, we now have data for about 0.4 sq deg in the Pleiades, corresponding roughly to 5% of the area of that cluster. We have searched the new CCD frames for additional Pleiades brown dwarf candidates. Two possible candidates are present, the faintest of which has V approximately equal to 22.5, (V-I)(sub K) approximately equal to 4.6. Because we do not have proper motion data and the colors of these objects are not redder than the reddest known field stars, it is possible that some or all of our candidates are somewhat higher mass field stars rather than Pleiades-age brown dwarfs. Even if all six of the proposed brown dwarf candidates in our 0.4 sq deg field are Pleiades members, the relatively small number found suggests that low mass stars or brown dwarfs do not contribute significantly to the total mass of the cluster.

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.

Guidance for Efficient Small Animal Imaging Quality Control.

PubMed

Osborne, Dustin R; Kuntner, Claudia; Berr, Stuart; Stout, David

2017-08-01

Routine quality control is a critical aspect of properly maintaining high-performance small animal imaging instrumentation. A robust quality control program helps produce more reliable data both for academic purposes and as proof of system performance for contract imaging work. For preclinical imaging laboratories, the combination of costs and available resources often limits their ability to produce efficient and effective quality control programs. This work presents a series of simplified quality control procedures that are accessible to a wide range of preclinical imaging laboratories. Our intent is to provide minimum guidelines for routine quality control that can assist preclinical imaging specialists in setting up an appropriate quality control program for their facility.

The effect of image sharpness on quantitative eye movement data and on image quality evaluation while viewing natural images

NASA Astrophysics Data System (ADS)

Vuori, Tero; Olkkonen, Maria

2006-01-01

The aim of the study is to test both customer image quality rating (subjective image quality) and physical measurement of user behavior (eye movements tracking) to find customer satisfaction differences in imaging technologies. Methodological aim is to find out whether eye movements could be quantitatively used in image quality preference studies. In general, we want to map objective or physically measurable image quality to subjective evaluations and eye movement data. We conducted a series of image quality tests, in which the test subjects evaluated image quality while we recorded their eye movements. Results show that eye movement parameters consistently change according to the instructions given to the user, and according to physical image quality, e.g. saccade duration increased with increasing blur. Results indicate that eye movement tracking could be used to differentiate image quality evaluation strategies that the users have. Results also show that eye movements would help mapping between technological and subjective image quality. Furthermore, these results give some empirical emphasis to top-down perception processes in image quality perception and evaluation by showing differences between perceptual processes in situations when cognitive task varies.

Global quality imaging: improvement actions.

PubMed

Lau, Lawrence S; Pérez, Maria R; Applegate, Kimberly E; Rehani, Madan M; Ringertz, Hans G; George, Robert

2011-05-01

Workforce shortage, workload increase, workplace changes, and budget challenges are emerging issues around the world, which could place quality imaging at risk. It is important for imaging stakeholders to collaborate, ensure patient safety, improve the quality of care, and address these issues. There is no single panacea. A range of improvement measures, strategies, and actions are required. Examples of improvement actions supporting the 3 quality measures are described under 5 strategies: conducting research, promoting awareness, providing education and training, strengthening infrastructure, and implementing policies. The challenge is to develop long-term, cost-effective, system-based improvement actions that will bring better outcomes and underpin a sustainable future for quality imaging. In an imaging practice, these actions will result in selecting the right procedure (justification), using the right dose (optimization), and preventing errors along the patient journey. To realize this vision and implement these improvement actions, a range of expertise and adequate resources are required. Stakeholders should collaborate and work together. In today's globalized environment, collaboration is strength and provides synergy to achieve better outcomes and greater success. Copyright © 2011 American College of Radiology. Published by Elsevier Inc. All rights reserved.

ESA's CCD test bench for the PLATO mission

NASA Astrophysics Data System (ADS)

Beaufort, Thierry; Duvet, Ludovic; Bloemmaert, Sander; Lemmel, Frederic; Prod'homme, Thibaut; Verhoeve, Peter; Smit, Hans; Butler, Bart; van der Luijt, Cornelis; Heijnen, Jerko; Visser, Ivo

2016-08-01

PLATO { PLAnetary Transits and Oscillations of stars { is the third medium-class mission to be selected in the European Space Agency (ESA) Science and Robotic Exploration Cosmic Vision programme. Due for launch in 2025, the payload makes use of a large format (8 cm x 8 cm) Charge-Coupled Devices (CCDs), the e2v CCD270 operated at 4 MHz and at -70 C. To de-risk the PLATO CCD qualification programme initiated in 2014 and support the mission definition process, ESA's Payload Technology Validation section from the Future Missions Office has developed a dedicated test bench.

Ion profiling in an ambient drift tube-ion mobility spectrometer using a high pixel density linear array detector IonCCD.

PubMed

Davila, Stephen J; Hadjar, Omar; Eiceman, Gary A

2013-07-16

A linear pixel-based detector array, the IonCCD, is characterized for use under ambient conditions with thermal (<1 eV) positive ions derived from purified air and a 10 mCi (63)Ni foil. The IonCCD combined with a drift tube-ion mobility spectrometer permitted the direct detection of gas phase ions at atmospheric pressure and confirmed a limit of detection of 3000 ions/pixel/frame established previously in both the keV (1-2 keV) and the hyper-thermal (10-40 eV) regimes. Results demonstrate the "broad-band" application of the IonCCD over 10(5) orders in ion energy and over 10(10) in operating pressure. The Faraday detector of a drift tube for an ion mobility spectrometer was replaced with the IonCCD providing images of ion profiles over the cross-section of the drift tube. Patterns in the ion profiles were developed in the drift tube cross-section by control of electric fields between wires of Bradbury Nielson and Tyndall Powell shutter designs at distances of 1-8 cm from the detector. Results showed that ion beams formed in wire sets, retained their shape with limited mixing by diffusion and Coulombic repulsion. Beam broadening determined as 95 μm/cm for hydrated protons in air with moisture of ~10 ppmv. These findings suggest a value of the IonCCD in further studies of ion motion and diffusion of thermalized ions, enhancing computational results from simulation programs, and in the design or operation of ion mobility spectrometers.

Medición de coeficientes de extinción en CASLEO y características del CCD ROPER-2048B del telescopio JS

NASA Astrophysics Data System (ADS)

Fernández-Lajús, E.; Gamen, R.; Sánchez, M.; Scalia, M. C.; Baume, G. L.

2016-08-01

From observations made with the ``Jorge Sahade'' telescope of the Complejo Astronomico El Leoncito, the UBVRI-band extinction coeficients were measured, and some parameters and characteristics of the direct-image CCD camera ROPER 2048B were determined.

CCD Astrometric Measurements of Double Stars BAL 746, BPM 342, KU 92, and STF 897

NASA Astrophysics Data System (ADS)

Smith, Schuyler

2017-07-01

Double stars WDS 06589-0106 (BAL 746), WDS 06579+1430 (BPM 342), WDS 07006+0921 (KU 92), and WDS 06224+2640 (STF 897) were measured as part of a science fair project for the 2016 Greater San Diego Science and Engineering Fair. The goal was to measure the separation and position angles of stars by using a telescope with a charge-coupled device (CCD) on the iTelescope network. Five images were taken of each of the stars. These images were plate solved with Visual PinPoint and measured using Aladin Sky Atlas. Measurements for all five doubles compare well to the more recent values in the Washington Double Star Catalog.

Initial results from a cryogenic proton irradiation of a p-channel CCD

NASA Astrophysics Data System (ADS)

Gow, J. P. D.; Wood, D.; Burt, D.; Hall, D. J.; Dryer, B.; Holland, A. D.; Murray, N. J.

2015-08-01

The displacement damage hardness that can be achieved using p-channel charge coupled devices (CCD) was originally demonstrated in 1997 and since then a number of other studies have demonstrated an improved tolerance to radiationinduced CTI when compared to n-channel CCDs. A number of recent studies have also shown that the temperature history of the device after the irradiation impacts the performance of the detector, linked to the mobility of defects at different temperatures. This study describes the initial results from an e2v technologies p-channel CCD204 irradiated at 153 K with a 10 MeV equivalent proton fluences of 1.24×109 and 1.24×1011 protons.cm-2. The number of defects identified using trap pumping, dark current and cosmetic quality immediately after irradiation and over a period of 150 hours after the irradiation with the device held at 153 K and then after different periods of time at room temperature are described. The device also exhibited a flatband voltage shift of around 30 mV per krad, determined by the reduction in full well capacity.

A design of driving circuit for star sensor imaging camera

NASA Astrophysics Data System (ADS)

Li, Da-wei; Yang, Xiao-xu; Han, Jun-feng; Liu, Zhao-hui

2016-01-01

The star sensor is a high-precision attitude sensitive measuring instruments, which determine spacecraft attitude by detecting different positions on the celestial sphere. Imaging camera is an important portion of star sensor. The purpose of this study is to design a driving circuit based on Kodak CCD sensor. The design of driving circuit based on Kodak KAI-04022 is discussed, and the timing of this CCD sensor is analyzed. By the driving circuit testing laboratory and imaging experiments, it is found that the driving circuits can meet the requirements of Kodak CCD sensor.

Objective quality assessment of tone-mapped images.

PubMed

Yeganeh, Hojatollah; Wang, Zhou

2013-02-01

Tone-mapping operators (TMOs) that convert high dynamic range (HDR) to low dynamic range (LDR) images provide practically useful tools for the visualization of HDR images on standard LDR displays. Different TMOs create different tone-mapped images, and a natural question is which one has the best quality. Without an appropriate quality measure, different TMOs cannot be compared, and further improvement is directionless. Subjective rating may be a reliable evaluation method, but it is expensive and time consuming, and more importantly, is difficult to be embedded into optimization frameworks. Here we propose an objective quality assessment algorithm for tone-mapped images by combining: 1) a multiscale signal fidelity measure on the basis of a modified structural similarity index and 2) a naturalness measure on the basis of intensity statistics of natural images. Validations using independent subject-rated image databases show good correlations between subjective ranking score and the proposed tone-mapped image quality index (TMQI). Furthermore, we demonstrate the extended applications of TMQI using two examples-parameter tuning for TMOs and adaptive fusion of multiple tone-mapped images.

Soft x-ray imager (SXI) onboard the NeXT satellite

NASA Astrophysics Data System (ADS)

Tsuru, Takeshi Go; Takagi, Shin-Ichiro; Matsumoto, Hironori; Inui, Tatsuya; Ozawa, Midori; Koyama, Katsuji; Tsunemi, Hiroshi; Hayashida, Kiyoshi; Miyata, Emi; Ozawa, Hideki; Touhiguchi, Masakuni; Matsuura, Daisuke; Dotani, Tadayasu; Ozaki, Masanobu; Murakami, Hiroshi; Kohmura, Takayoshi; Kitamoto, Shunji; Awaki, Hisamitsu

2006-06-01

We give overview and the current status of the development of the Soft X-ray Imager (SXI) onboard the NeXT satellite. SXI is an X-ray CCD camera placed at the focal plane detector of the Soft X-ray Telescopes for Imaging (SXT-I) onboard NeXT. The pixel size and the format of the CCD is 24 x 24μm (IA) and 2048 x 2048 x 2 (IA+FS). Currently, we have been developing two types of CCD as candidates for SXI, in parallel. The one is front illumination type CCD with moderate thickness of the depletion layer (70 ~ 100μm) as a baseline plan. The other one is the goal plan, in which we develop back illumination type CCD with a thick depletion layer (200 ~ 300μm). For the baseline plan, we successfully developed the proto model 'CCD-NeXT1' with the pixel size of 12μm x 12μm and the CCD size of 24mm x 48mm. The depletion layer of the CCD has reached 75 ~ 85μm. The goal plan is realized by introduction of a new type of CCD 'P-channel CCD', which collects holes in stead of electrons in the common 'N-channel CCD'. By processing a test model of P-channel CCD we have confirmed high quantum efficiency above 10 keV with an equivalent depletion layer of 300μm. A back illumination type of P-channel CCD with a depletion layer of 200μm with aluminum coating for optical blocking has been also successfully developed. We have been also developing a thermo-electric cooler (TEC) with the function of the mechanically support of the CCD wafer without standoff insulators, for the purpose of the reduction of thermal input to the CCD through the standoff insulators. We have been considering the sensor housing and the onboard electronics for the CCD clocking, readout and digital processing of the frame date.

Low-cost oblique illumination: an image quality assessment.

PubMed

Ruiz-Santaquiteria, Jesus; Espinosa-Aranda, Jose Luis; Deniz, Oscar; Sanchez, Carlos; Borrego-Ramos, Maria; Blanco, Saul; Cristobal, Gabriel; Bueno, Gloria

2018-01-01

We study the effectiveness of several low-cost oblique illumination filters to improve overall image quality, in comparison with standard bright field imaging. For this purpose, a dataset composed of 3360 diatom images belonging to 21 taxa was acquired. Subjective and objective image quality assessments were done. The subjective evaluation was performed by a group of diatom experts by psychophysical test where resolution, focus, and contrast were assessed. Moreover, some objective nonreference image quality metrics were applied to the same image dataset to complete the study, together with the calculation of several texture features to analyze the effect of these filters in terms of textural properties. Both image quality evaluation methods, subjective and objective, showed better results for images acquired using these illumination filters in comparison with the no filtered image. These promising results confirm that this kind of illumination filters can be a practical way to improve the image quality, thanks to the simple and low cost of the design and manufacturing process. (2018) COPYRIGHT Society of Photo-Optical Instrumentation Engineers (SPIE).

Evaluating a CCD film digitizer: comparing interpretation accuracy with original film readings

NASA Astrophysics Data System (ADS)

Gitlin, Joseph N.; Scott, William W., Jr.; Bell, Kathryn; Narayan, Anand

2002-04-01

The purpose of the study was to determine if there were differences between the interpretations of radiographic images resulting from digitizing films using a recently developed CCD unit, and the readings of the original films. The general hypothesis to be tested was that there were no significant differences in the measures of accuracy, sensitivity, specificity and ROC analyses when the interpretations related to the two modes were compared. The authors selected 120 radiographic examinations for the study from departmental teaching files, which included chest, abdomen, extremity and other cases that were considered difficult to interpret. The authors also selected six specific abnormalities visualized on 60 of the cases as true positives to classify the reports. After anonymizing the patient identification, the films were digitized and independently interpreted by four board-certified radiologists. Each reader read all of the examinations, half on film alternators and the other half on a high-resolution soft-copy workstation. No reader interpreted the same examination more than once. As of this date, the preliminary results indicate that the hypothesis will be accepted, but more analyses of the data must be performed to confirm the early findings. The additional work will include complete verification of data entry and classification of interpretations, a detailed review of perceived image quality and completion of the ROC analysis by pairs of readers. If the results are confirmed, radiologists, other physicians and administrators will have another reliable option to conventional film practice through increased access to remote primary diagnosis and consultation using high-speed telecommunication media.

Quality metrics for sensor images

NASA Technical Reports Server (NTRS)

Ahumada, AL

1993-01-01

Methods are needed for evaluating the quality of augmented visual displays (AVID). Computational quality metrics will help summarize, interpolate, and extrapolate the results of human performance tests with displays. The FLM Vision group at NASA Ames has been developing computational models of visual processing and using them to develop computational metrics for similar problems. For example, display modeling systems use metrics for comparing proposed displays, halftoning optimizing methods use metrics to evaluate the difference between the halftone and the original, and image compression methods minimize the predicted visibility of compression artifacts. The visual discrimination models take as input two arbitrary images A and B and compute an estimate of the probability that a human observer will report that A is different from B. If A is an image that one desires to display and B is the actual displayed image, such an estimate can be regarded as an image quality metric reflecting how well B approximates A. There are additional complexities associated with the problem of evaluating the quality of radar and IR enhanced displays for AVID tasks. One important problem is the question of whether intruding obstacles are detectable in such displays. Although the discrimination model can handle detection situations by making B the original image A plus the intrusion, this detection model makes the inappropriate assumption that the observer knows where the intrusion will be. Effects of signal uncertainty need to be added to our models. A pilot needs to make decisions rapidly. The models need to predict not just the probability of a correct decision, but the probability of a correct decision by the time the decision needs to be made. That is, the models need to predict latency as well as accuracy. Luce and Green have generated models for auditory detection latencies. Similar models are needed for visual detection. Most image quality models are designed for static imagery

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.

A Dynamic Image Quality Evaluation of Videofluoroscopy Images: Considerations for Telepractice Applications.

PubMed

Burns, Clare L; Keir, Benjamin; Ward, Elizabeth C; Hill, Anne J; Farrell, Anna; Phillips, Nick; Porter, Linda

2015-08-01

High-quality fluoroscopy images are required for accurate interpretation of videofluoroscopic swallow studies (VFSS) by speech pathologists and radiologists. Consequently, integral to developing any system to conduct VFSS remotely via telepractice is ensuring that the quality of the VFSS images transferred via the telepractice system is optimized. This study evaluates the extent of change observed in image quality when videofluoroscopic images are transmitted from a digital fluoroscopy system to (a) current clinical equipment (KayPentax Digital Swallowing Workstation, and b) four different telepractice system configurations. The telepractice system configurations consisted of either a local C20 or C60 Cisco TelePresence System (codec unit) connected to the digital fluoroscopy system and linked to a second remote C20 or C60 Cisco TelePresence System via a network running at speeds of either 2, 4 or 6 megabits per second (Mbit/s). Image quality was tested using the NEMA XR 21 Phantom, and results demonstrated some loss in spatial resolution, low contrast detectability and temporal resolution for all transferred images when compared to the fluoroscopy source. When using higher capacity codec units and/or the highest bandwidths to support data transmission, image quality transmitted through the telepractice system was found to be comparable if not better than the current clinical system. This study confirms that telepractice systems can be designed to support fluoroscopy image transfer and highlights important considerations when developing telepractice systems for VFSS analysis to ensure high-quality radiological image reproduction.

Improving the ability of image sensors to detect faint stars and moving objects using image deconvolution techniques.

PubMed

Fors, Octavi; Núñez, Jorge; Otazu, Xavier; Prades, Albert; Cardinal, Robert D

2010-01-01

In this paper we show how the techniques of image deconvolution can increase the ability of image sensors as, for example, CCD imagers, to detect faint stars or faint orbital objects (small satellites and space debris). In the case of faint stars, we show that this benefit is equivalent to double the quantum efficiency of the used image sensor or to increase the effective telescope aperture by more than 30% without decreasing the astrometric precision or introducing artificial bias. In the case of orbital objects, the deconvolution technique can double the signal-to-noise ratio of the image, which helps to discover and control dangerous objects as space debris or lost satellites. The benefits obtained using CCD detectors can be extrapolated to any kind of image sensors.

The In-flight Spectroscopic Performance of the Swift XRT CCD Camera During 2006-2007

NASA Technical Reports Server (NTRS)

Godet, O.; Beardmore, A.P.; Abbey, A.F.; Osborne, J.P.; Page, K.L.; Evans, P.; Starling, R.; Wells, A.A.; Angelini, L.; Burrows, D.N.;

Learning to rank for blind image quality assessment.

PubMed

Gao, Fei; Tao, Dacheng; Gao, Xinbo; Li, Xuelong

2015-10-01

Blind image quality assessment (BIQA) aims to predict perceptual image quality scores without access to reference images. State-of-the-art BIQA methods typically require subjects to score a large number of images to train a robust model. However, subjective quality scores are imprecise, biased, and inconsistent, and it is challenging to obtain a large-scale database, or to extend existing databases, because of the inconvenience of collecting images, training the subjects, conducting subjective experiments, and realigning human quality evaluations. To combat these limitations, this paper explores and exploits preference image pairs (PIPs) such as the quality of image Ia is better than that of image Ib for training a robust BIQA model. The preference label, representing the relative quality of two images, is generally precise and consistent, and is not sensitive to image content, distortion type, or subject identity; such PIPs can be generated at a very low cost. The proposed BIQA method is one of learning to rank. We first formulate the problem of learning the mapping from the image features to the preference label as one of classification. In particular, we investigate the utilization of a multiple kernel learning algorithm based on group lasso to provide a solution. A simple but effective strategy to estimate perceptual image quality scores is then presented. Experiments show that the proposed BIQA method is highly effective and achieves a performance comparable with that of state-of-the-art BIQA algorithms. Moreover, the proposed method can be easily extended to new distortion categories.

Standardizing Quality Assessment of Fused Remotely Sensed Images

NASA Astrophysics Data System (ADS)

Pohl, C.; Moellmann, J.; Fries, K.

2017-09-01

The multitude of available operational remote sensing satellites led to the development of many image fusion techniques to provide high spatial, spectral and temporal resolution images. The comparison of different techniques is necessary to obtain an optimized image for the different applications of remote sensing. There are two approaches in assessing image quality: 1. Quantitatively by visual interpretation and 2. Quantitatively using image quality indices. However an objective comparison is difficult due to the fact that a visual assessment is always subject and a quantitative assessment is done by different criteria. Depending on the criteria and indices the result varies. Therefore it is necessary to standardize both processes (qualitative and quantitative assessment) in order to allow an objective image fusion quality evaluation. Various studies have been conducted at the University of Osnabrueck (UOS) to establish a standardized process to objectively compare fused image quality. First established image fusion quality assessment protocols, i.e. Quality with No Reference (QNR) and Khan's protocol, were compared on varies fusion experiments. Second the process of visual quality assessment was structured and standardized with the aim to provide an evaluation protocol. This manuscript reports on the results of the comparison and provides recommendations for future research.

Comparing the TYCHO Catalogue with CCD Astrograph Observations

NASA Astrophysics Data System (ADS)

Zacharias, N.; Hoeg, E.; Urban, S. E.; Corbin, T. E.

1997-08-01

Selected fields around radio-optical reference frame sources have been observed with the U.S. Naval Observatory CCD astrograph (UCA). This telescope is equipped with a red-corrected 206mm 5-element lens and a 4k by 4k CCD camera which provides a 1 square degree field of view. Positions with internal precisions of 20 mas for stars in the 7 to 12 magnitude range have been obtained with 30 second exposures. A comparison is made with the Tycho Catalogue, which is accurate to about 5 to 50 mas at mean epoch of J1991.25, depending on the magnitude of the star. Preliminary proper motions are obtained using the Astrographic Catalogue (AC) to update the Tycho positions to the epoch of the UCA observations, which adds an error contribution of about 15 to 20 mas. Individual CCD frames have been reduced with an average of 30 Tycho reference stars per frame. A linear plate model gives an average adjustment standard error of 46 mas, consistent with the internal errors. The UCA is capable of significantly improving the positions of Tycho stars fainter than about visual magnitude 9.5.

Image quality evaluation of full reference algorithm

NASA Astrophysics Data System (ADS)

He, Nannan; Xie, Kai; Li, Tong; Ye, Yushan

2018-03-01

Image quality evaluation is a classic research topic, the goal is to design the algorithm, given the subjective feelings consistent with the evaluation value. This paper mainly introduces several typical reference methods of Mean Squared Error(MSE), Peak Signal to Noise Rate(PSNR), Structural Similarity Image Metric(SSIM) and feature similarity(FSIM) of objective evaluation methods. The different evaluation methods are tested by Matlab, and the advantages and disadvantages of these methods are obtained by analyzing and comparing them.MSE and PSNR are simple, but they are not considered to introduce HVS characteristics into image quality evaluation. The evaluation result is not ideal. SSIM has a good correlation and simple calculation ,because it is considered to the human visual effect into image quality evaluation,However the SSIM method is based on a hypothesis,The evaluation result is limited. The FSIM method can be used for test of gray image and color image test, and the result is better. Experimental results show that the new image quality evaluation algorithm based on FSIM is more accurate.

High-quality compressive ghost imaging

NASA Astrophysics Data System (ADS)

Huang, Heyan; Zhou, Cheng; Tian, Tian; Liu, Dongqi; Song, Lijun

2018-04-01

We propose a high-quality compressive ghost imaging method based on projected Landweber regularization and guided filter, which effectively reduce the undersampling noise and improve the resolution. In our scheme, the original object is reconstructed by decomposing of regularization and denoising steps instead of solving a minimization problem in compressive reconstruction process. The simulation and experimental results show that our method can obtain high ghost imaging quality in terms of PSNR and visual observation.

Examples of subjective image quality enhancement in multimedia

NASA Astrophysics Data System (ADS)

Klíma, Miloš; Pazderák, Jiří; Fliegel, Karel

2007-09-01

The subjective image quality is an important issue in all multimedia imaging systems with a significant impact onto QoS (Quality of Service). For long time the image fidelity criterion was widely applied in technical systems esp. in both television and image source compression fields but the optimization of subjective perception quality and fidelity approach (such as the minimum of MSE) are very different. The paper presents an experimental testing of three different digital techniques for the subjective image quality enhancement - color saturation, edge enhancement, denoising operators and noise addition - well known from both the digital photography and video. The evaluation has been done for extensive operator parameterization and the results are summarized and discussed. It has been demonstrated that there are relevant types of image corrections improving to some extent the subjective perception of the image. The above mentioned techniques have been tested for five image tests with significantly different image characteristics (fine details, large saturated color areas, high color contrast, easy-to-remember colors etc.). The experimental results show the way to optimized use of image enhancing operators. Finally the concept of impressiveness as a new possible expression of subjective quality improvement is presented and discussed.

dipIQ: Blind Image Quality Assessment by Learning-to-Rank Discriminable Image Pairs.

PubMed

Ma, Kede; Liu, Wentao; Liu, Tongliang; Wang, Zhou; Tao, Dacheng

2017-05-26

Objective assessment of image quality is fundamentally important in many image processing tasks. In this work, we focus on learning blind image quality assessment (BIQA) models which predict the quality of a digital image with no access to its original pristine-quality counterpart as reference. One of the biggest challenges in learning BIQA models is the conflict between the gigantic image space (which is in the dimension of the number of image pixels) and the extremely limited reliable ground truth data for training. Such data are typically collected via subjective testing, which is cumbersome, slow, and expensive. Here we first show that a vast amount of reliable training data in the form of quality-discriminable image pairs (DIP) can be obtained automatically at low cost by exploiting largescale databases with diverse image content. We then learn an opinion-unaware BIQA (OU-BIQA, meaning that no subjective opinions are used for training) model using RankNet, a pairwise learning-to-rank (L2R) algorithm, from millions of DIPs, each associated with a perceptual uncertainty level, leading to a DIP inferred quality (dipIQ) index. Extensive experiments on four benchmark IQA databases demonstrate that dipIQ outperforms state-of-the-art OU-BIQA models. The robustness of dipIQ is also significantly improved as confirmed by the group MAximum Differentiation (gMAD) competition method. Furthermore, we extend the proposed framework by learning models with ListNet (a listwise L2R algorithm) on quality-discriminable image lists (DIL). The resulting DIL Inferred Quality (dilIQ) index achieves an additional performance gain.

Performance evaluation of no-reference image quality metrics for face biometric images

NASA Astrophysics Data System (ADS)

Liu, Xinwei; Pedersen, Marius; Charrier, Christophe; Bours, Patrick

2018-03-01

The accuracy of face recognition systems is significantly affected by the quality of face sample images. The recent established standardization proposed several important aspects for the assessment of face sample quality. There are many existing no-reference image quality metrics (IQMs) that are able to assess natural image quality by taking into account similar image-based quality attributes as introduced in the standardization. However, whether such metrics can assess face sample quality is rarely considered. We evaluate the performance of 13 selected no-reference IQMs on face biometrics. The experimental results show that several of them can assess face sample quality according to the system performance. We also analyze the strengths and weaknesses of different IQMs as well as why some of them failed to assess face sample quality. Retraining an original IQM by using face database can improve the performance of such a metric. In addition, the contribution of this paper can be used for the evaluation of IQMs on other biometric modalities; furthermore, it can be used for the development of multimodality biometric IQMs.

A comparison of imaging methods for use in an array biosensor

NASA Technical Reports Server (NTRS)

Golden, Joel P.; Ligler, Frances S.

2002-01-01

An array biosensor has been developed which uses an actively-cooled, charge-coupled device (CCD) imager. In an effort to save money and space, a complementary metal-oxide semiconductor (CMOS) camera and photodiode were tested as replacements for the cooled CCD imager. Different concentrations of CY5 fluorescent dye in glycerol were imaged using the three different detection systems with the same imaging optics. Signal discrimination above noise was compared for each of the three systems.

SU-F-J-190: Time Resolved Range Measurement System Using Scintillator and CCD Camera for the Slow Beam Extraction

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

Saotome, N; Furukawa, T; Mizushima, K

2016-06-15

Purpose: To investigate the time structure of the range, we have verified the rang shift due to the betatron tune shift with several synchrotron parameters. Methods: A cylindrical plastic scintillator block and a CCD camera were installed on the black box. Using image processing, the range was determined the 80 percent of distal dose of the depth light distribution. The root mean square error of the range measurement using the scintillator and CCD system is about 0.2 mm. Range measurement was performed at interval of 170 msec. The chromaticity of the synchrotron was changed in the range of plus ormore » minus 1% from reference chromaticity in this study. All of the particle inside the synchrotron ring were extracted with the output beam intensity 1.8×10{sup 8} and 5.0×10{sub 7} particle per sec. Results: The time strictures of the range were changed by changing of the chromaticity. The reproducibility of the measurement was sufficient to observe the time structures of the range. The range shift was depending on the number of the residual particle inside the synchrotron ring. Conclusion: In slow beam extraction for scanned carbon-ion therapy, the range shift is undesirable because it causes the dose uncertainty in the target. We introduced the time-resolved range measurement using scintillator and CCD system. The scintillator and CCD system have enabled to verify the range shift with sufficient spatial resolution and reproducibility.« less

Improved Scanners for Microscopic Hyperspectral Imaging

NASA Technical Reports Server (NTRS)

Mao, Chengye

2009-01-01

Improved scanners to be incorporated into hyperspectral microscope-based imaging systems have been invented. Heretofore, in microscopic imaging, including spectral imaging, it has been customary to either move the specimen relative to the optical assembly that includes the microscope or else move the entire assembly relative to the specimen. It becomes extremely difficult to control such scanning when submicron translation increments are required, because the high magnification of the microscope enlarges all movements in the specimen image on the focal plane. To overcome this difficulty, in a system based on this invention, no attempt would be made to move either the specimen or the optical assembly. Instead, an objective lens would be moved within the assembly so as to cause translation of the image at the focal plane: the effect would be equivalent to scanning in the focal plane. The upper part of the figure depicts a generic proposed microscope-based hyperspectral imaging system incorporating the invention. The optical assembly of this system would include an objective lens (normally, a microscope objective lens) and a charge-coupled-device (CCD) camera. The objective lens would be mounted on a servomotor-driven translation stage, which would be capable of moving the lens in precisely controlled increments, relative to the camera, parallel to the focal-plane scan axis. The output of the CCD camera would be digitized and fed to a frame grabber in a computer. The computer would store the frame-grabber output for subsequent viewing and/or processing of images. The computer would contain a position-control interface board, through which it would control the servomotor. There are several versions of the invention. An essential feature common to all versions is that the stationary optical subassembly containing the camera would also contain a spatial window, at the focal plane of the objective lens, that would pass only a selected portion of the image. In one version

Images of the laser entrance hole from the static x-ray imager at NIF.

PubMed

Schneider, M B; Jones, O S; Meezan, N B; Milovich, J L; Town, R P; Alvarez, S S; Beeler, R G; Bradley, D K; Celeste, J R; Dixit, S N; Edwards, M J; Haugh, M J; Kalantar, D H; Kline, J L; Kyrala, G A; Landen, O L; MacGowan, B J; Michel, P; Moody, J D; Oberhelman, S K; Piston, K W; Pivovaroff, M J; Suter, L J; Teruya, A T; Thomas, C A; Vernon, S P; Warrick, A L; Widmann, K; Wood, R D; Young, B K

2010-10-01

The static x-ray imager at the National Ignition Facility is a pinhole camera using a CCD detector to obtain images of Hohlraum wall x-ray drive illumination patterns seen through the laser entrance hole (LEH). Carefully chosen filters, combined with the CCD response, allow recording images in the x-ray range of 3-5 keV with 60 μm spatial resolution. The routines used to obtain the apparent size of the backlit LEH and the location and intensity of beam spots are discussed and compared to predictions. A new soft x-ray channel centered at 870 eV (near the x-ray peak of a 300 eV temperature ignition Hohlraum) is discussed.

Achieving quality in cardiovascular imaging: proceedings from the American College of Cardiology-Duke University Medical Center Think Tank on Quality in Cardiovascular Imaging.

PubMed

Douglas, Pamela; Iskandrian, Ami E; Krumholz, Harlan M; Gillam, Linda; Hendel, Robert; Jollis, James; Peterson, Eric; Chen, Jersey; Masoudi, Frederick; Mohler, Emile; McNamara, Robert L; Patel, Manesh R; Spertus, John

2006-11-21

Cardiovascular imaging has enjoyed both rapid technological advances and sustained growth, yet less attention has been focused on quality than in other areas of cardiovascular medicine. To address this deficit, representatives from cardiovascular imaging societies, private payers, government agencies, the medical imaging industry, and experts in quality measurement met, and this report provides an overview of the discussions. A consensus definition of quality in imaging and a convergence of opinion on quality measures across imaging modalities was achieved and are intended to be the start of a process culminating in the development, dissemination, and adoption of quality measures for all cardiovascular imaging modalities.

Rapid Raman spectroscopy of musculoskeletal tissue using a visible laser and an electron-multiplying CCD (EMCCD) detector

NASA Astrophysics Data System (ADS)

Golcuk, Kurtulus; Mandair, Gurjit S.; Callender, Andrew F.; Finney, William F.; Sahar, Nadder; Kohn, David H.; Morris, Michael D.

2006-02-01

Background fluorescence can often complicate the use of Raman microspectroscopy in the study of musculoskeletal tissues. Such fluorescence interferences are undesirable as the Raman spectra of matrix and mineral phases can be used to differentiate between normal and pathological or microdamaged bone. Photobleaching with the excitation laser provides a non-invasive method for reducing background fluorescence, enabling 532 nm Raman hyperspectral imaging of bone tissue. The signal acquisition time for a 400 point Raman line image is reduced to 1-4 seconds using electronmultiplying CCD (EMCCD) detector, enabling acquisition of Raman images in less than 10 minutes. Rapid photobleaching depends upon multiple scattering effects in the tissue specimen and is applicable to some, but not all experimental situations.

Naturalness and interestingness of test images for visual quality evaluation

NASA Astrophysics Data System (ADS)

Halonen, Raisa; Westman, Stina; Oittinen, Pirkko

2011-01-01

Balanced and representative test images are needed to study perceived visual quality in various application domains. This study investigates naturalness and interestingness as image quality attributes in the context of test images. Taking a top-down approach we aim to find the dimensions which constitute naturalness and interestingness in test images and the relationship between these high-level quality attributes. We compare existing collections of test images (e.g. Sony sRGB images, ISO 12640 images, Kodak images, Nokia images and test images developed within our group) in an experiment combining quality sorting and structured interviews. Based on the data gathered we analyze the viewer-supplied criteria for naturalness and interestingness across image types, quality levels and judges. This study advances our understanding of subjective image quality criteria and enables the validation of current test images, furthering their development.

Agricultural produce grading and sorting system using color CCD and new color identification algorithm

NASA Astrophysics Data System (ADS)

Wang, Dongsheng; Zou, Jizuo; Yang, Yunping; Dong, Jianhua; Zhang, Yuanxiang

1996-10-01

A high-speed automatic agricultural produce grading and sorting system using color CCD and new color identification algorithm has been developed. In a typical application, the system can sort almonds into tow output grades according to their color. Almonds ar rich in 18 kinds of amino acids and 13 kinds of micro minerals and vitamins and can be made into almond drink. In order to ensure the drink quality, almonds must be sorted carefully before being made into a drink. Using this system, almonds can be sorted into two grades: up to grade and below grade almonds or foreign materials. A color CCD inspects the almonds passing on a conveyor of rotating rollers, a color identification algorithm grades almonds and distinguishes foreign materials from almonds. Employing an elaborately designed mechanism, the below grade almonds and foreign materials can be removed effectively from the raw almonds. This system can be easily adapted for inspecting and sorting other kinds of agricultural produce such as peanuts, beans tomatoes and so on.

A Design and Development of Multi-Purpose CCD Camera System with Thermoelectric Cooling: Software

NASA Astrophysics Data System (ADS)

Oh, S. H.; Kang, Y. W.; Byun, Y. I.

2007-12-01

We present a software which we developed for the multi-purpose CCD camera. This software can be used on the all 3 types of CCD - KAF-0401E (768×512), KAF-1602E (15367times;1024), KAF-3200E (2184×1472) made in KODAK Co.. For the efficient CCD camera control, the software is operated with two independent processes of the CCD control program and the temperature/shutter operation program. This software is designed to fully automatic operation as well as manually operation under LINUX system, and is controled by LINUX user signal procedure. We plan to use this software for all sky survey system and also night sky monitoring and sky observation. As our results, the read-out time of each CCD are about 15sec, 64sec, 134sec for KAF-0401E, KAF-1602E, KAF-3200E., because these time are limited by the data transmission speed of parallel port. For larger format CCD, the data transmission is required more high speed. we are considering this control software to one using USB port for high speed data transmission.

Improving the Ability of Image Sensors to Detect Faint Stars and Moving Objects Using Image Deconvolution Techniques

PubMed Central

Fors, Octavi; Núñez, Jorge; Otazu, Xavier; Prades, Albert; Cardinal, Robert D.

2010-01-01

In this paper we show how the techniques of image deconvolution can increase the ability of image sensors as, for example, CCD imagers, to detect faint stars or faint orbital objects (small satellites and space debris). In the case of faint stars, we show that this benefit is equivalent to double the quantum efficiency of the used image sensor or to increase the effective telescope aperture by more than 30% without decreasing the astrometric precision or introducing artificial bias. In the case of orbital objects, the deconvolution technique can double the signal-to-noise ratio of the image, which helps to discover and control dangerous objects as space debris or lost satellites. The benefits obtained using CCD detectors can be extrapolated to any kind of image sensors. PMID:22294896

Photometric correction for an optical CCD-based system based on the sparsity of an eight-neighborhood gray gradient.

PubMed

Zhang, Yuzhong; Zhang, Yan

2016-07-01

In an optical measurement and analysis system based on a CCD, due to the existence of optical vignetting and natural vignetting, photometric distortion, in which the intensity falls off away from the image center, affects the subsequent processing and measuring precision severely. To deal with this problem, an easy and straightforward method used for photometric distortion correction is presented in this paper. This method introduces a simple polynomial fitting model of the photometric distortion function and employs a particle swarm optimization algorithm to get these model parameters by means of a minimizing eight-neighborhood gray gradient. Compared with conventional calibration methods, this method can obtain the profile information of photometric distortion from only a single common image captured by the optical CCD-based system, with no need for a uniform luminance area source used as a standard reference source and relevant optical and geometric parameters in advance. To illustrate the applicability of this method, numerical simulations and photometric distortions with different lens parameters are evaluated using this method in this paper. Moreover, the application example of temperature field correction for casting billets also demonstrates the effectiveness of this method. The experimental results show that the proposed method is able to achieve the maximum absolute error for vignetting estimation of 0.0765 and the relative error for vignetting estimation from different background images of 3.86%.

Improving high resolution retinal image quality using speckle illumination HiLo imaging

PubMed Central

Zhou, Xiaolin; Bedggood, Phillip; Metha, Andrew

2014-01-01

Retinal image quality from flood illumination adaptive optics (AO) ophthalmoscopes is adversely affected by out-of-focus light scatter due to the lack of confocality. This effect is more pronounced in small eyes, such as that of rodents, because the requisite high optical power confers a large dioptric thickness to the retina. A recently-developed structured illumination microscopy (SIM) technique called HiLo imaging has been shown to reduce the effect of out-of-focus light scatter in flood illumination microscopes and produce pseudo-confocal images with significantly improved image quality. In this work, we adopted the HiLo technique to a flood AO ophthalmoscope and performed AO imaging in both (physical) model and live rat eyes. The improvement in image quality from HiLo imaging is shown both qualitatively and quantitatively by using spatial spectral analysis. PMID:25136486

Improving high resolution retinal image quality using speckle illumination HiLo imaging.

PubMed

Zhou, Xiaolin; Bedggood, Phillip; Metha, Andrew

2014-08-01

Retinal image quality from flood illumination adaptive optics (AO) ophthalmoscopes is adversely affected by out-of-focus light scatter due to the lack of confocality. This effect is more pronounced in small eyes, such as that of rodents, because the requisite high optical power confers a large dioptric thickness to the retina. A recently-developed structured illumination microscopy (SIM) technique called HiLo imaging has been shown to reduce the effect of out-of-focus light scatter in flood illumination microscopes and produce pseudo-confocal images with significantly improved image quality. In this work, we adopted the HiLo technique to a flood AO ophthalmoscope and performed AO imaging in both (physical) model and live rat eyes. The improvement in image quality from HiLo imaging is shown both qualitatively and quantitatively by using spatial spectral analysis.

Learning Receptive Fields and Quality Lookups for Blind Quality Assessment of Stereoscopic Images.

PubMed

Shao, Feng; Lin, Weisi; Wang, Shanshan; Jiang, Gangyi; Yu, Mei; Dai, Qionghai

2016-03-01

Blind quality assessment of 3D images encounters more new challenges than its 2D counterparts. In this paper, we propose a blind quality assessment for stereoscopic images by learning the characteristics of receptive fields (RFs) from perspective of dictionary learning, and constructing quality lookups to replace human opinion scores without performance loss. The important feature of the proposed method is that we do not need a large set of samples of distorted stereoscopic images and the corresponding human opinion scores to learn a regression model. To be more specific, in the training phase, we learn local RFs (LRFs) and global RFs (GRFs) from the reference and distorted stereoscopic images, respectively, and construct their corresponding local quality lookups (LQLs) and global quality lookups (GQLs). In the testing phase, blind quality pooling can be easily achieved by searching optimal GRF and LRF indexes from the learnt LQLs and GQLs, and the quality score is obtained by combining the LRF and GRF indexes together. Experimental results on three publicly 3D image quality assessment databases demonstrate that in comparison with the existing methods, the devised algorithm achieves high consistent alignment with subjective assessment.

Preparation of New Scintillation Imaging Material Composed of Scintillator-Silica Fine Powders and its Imaging of Tritium.

PubMed

Miyoshi, Hirokazu; Hiroura, Mitsunori; Tsujimoto, Kazunori; Irikura, Namiko; Otani, Tamaki; Shinohara, Yasuo

2017-05-01

A new scintillation imaging material [scintillator-silica fine powder (FP)] was prepared using silica FPs and scintillator-encapsulating silica nanoparticles (NPs) (scintillator-silica NPs). The wt% values of scintillator-silica NPs on the scintillator-silica FPs were 38, 43, 36 and 44%. Scintillation images of 3H, 63Ni, 35S, 33P, 204Tl, 89Sr and 32P dropped on the scintillator-silica FPs were obtained at about 37 kBq per 0.1-10 µl with a charge-coupled device (CCD) imager for a 5 min exposure. In particular, high-intensity CCD images of 35S were selectively obtained using the 2.25, 4.77 and 10 µm silica FPs with scintillator-silica NPs owing to the residual S of dimethyl sulfoxide in the preparation. Scintillation images of 3H at 1670 ± 9 Bq/0.5 µl and 347 ± 6 Bq/0.5 µl dropped in a 2 mm hole on the scintillator-silica FPs (6.78 and 10 µm) were also obtained using the CCD imager for a 2 h exposure. © The Author 2016. Published by Oxford University Press. All rights reserved. For Permissions, please email: journals.permissions@oup.com.

Image Quality in High-resolution and High-cadence Solar Imaging

NASA Astrophysics Data System (ADS)

Denker, C.; Dineva, E.; Balthasar, H.; Verma, M.; Kuckein, C.; Diercke, A.; González Manrique, S. J.

2018-03-01

Broad-band imaging and even imaging with a moderate bandpass (about 1 nm) provides a photon-rich environment, where frame selection (lucky imaging) becomes a helpful tool in image restoration, allowing us to perform a cost-benefit analysis on how to design observing sequences for imaging with high spatial resolution in combination with real-time correction provided by an adaptive optics (AO) system. This study presents high-cadence (160 Hz) G-band and blue continuum image sequences obtained with the High-resolution Fast Imager (HiFI) at the 1.5-meter GREGOR solar telescope, where the speckle-masking technique is used to restore images with nearly diffraction-limited resolution. The HiFI employs two synchronized large-format and high-cadence sCMOS detectors. The median filter gradient similarity (MFGS) image-quality metric is applied, among others, to AO-corrected image sequences of a pore and a small sunspot observed on 2017 June 4 and 5. A small region of interest, which was selected for fast-imaging performance, covered these contrast-rich features and their neighborhood, which were part of Active Region NOAA 12661. Modifications of the MFGS algorithm uncover the field- and structure-dependency of this image-quality metric. However, MFGS still remains a good choice for determining image quality without a priori knowledge, which is an important characteristic when classifying the huge number of high-resolution images contained in data archives. In addition, this investigation demonstrates that a fast cadence and millisecond exposure times are still insufficient to reach the coherence time of daytime seeing. Nonetheless, the analysis shows that data acquisition rates exceeding 50 Hz are required to capture a substantial fraction of the best seeing moments, significantly boosting the performance of post-facto image restoration.

Scalable Track Detection in SAR CCD Images

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

Chow, James G; Quach, Tu-Thach

Existing methods to detect vehicle tracks in coherent change detection images, a product of combining two synthetic aperture radar images ta ken at different times of the same scene, rely on simple, fast models to label track pixels. These models, however, are often too simple to capture natural track features such as continuity and parallelism. We present a simple convolutional network architecture consisting of a series of 3-by-3 convolutions to detect tracks. The network is trained end-to-end to learn natural track features entirely from data. The network is computationally efficient and improves the F-score on a standard dataset to 0.988,more » up fr om 0.907 obtained by the current state-of-the-art method.« less

On pictures and stuff: image quality and material appearance

NASA Astrophysics Data System (ADS)

Ferwerda, James A.

2014-02-01

Realistic images are a puzzle because they serve as visual representations of objects while also being objects themselves. When we look at an image we are able to perceive both the properties of the image and the properties of the objects represented by the image. Research on image quality has typically focused improving image properties (resolution, dynamic range, frame rate, etc.) while ignoring the issue of whether images are serving their role as visual representations. In this paper we describe a series of experiments that investigate how well images of different quality convey information about the properties of the objects they represent. In the experiments we focus on the effects that two image properties (contrast and sharpness) have on the ability of images to represent the gloss of depicted objects. We found that different experimental methods produced differing results. Specifically, when the stimulus images were presented using simultaneous pair comparison, observers were influenced by the surface properties of the images and conflated changes in image contrast and sharpness with changes in object gloss. On the other hand, when the stimulus images were presented sequentially, observers were able to disregard the image plane properties and more accurately match the gloss of the objects represented by the different quality images. These findings suggest that in understanding image quality it is useful to distinguish between quality of the imaging medium and the quality of the visual information represented by that medium.

A CCD experimental platform for large telescope in Antarctica based on FPGA

NASA Astrophysics Data System (ADS)

Zhu, Yuhua; Qi, Yongjun

2014-07-01

The CCD , as a detector , is one of the important components of astronomical telescopes. For a large telescope in Antarctica, a set of CCD detector system with large size, high sensitivity and low noise is indispensable. Because of the extremely low temperatures and unattended, system maintenance and software and hardware upgrade become hard problems. This paper introduces a general CCD controller experiment platform, using Field programmable gate array FPGA, which is, in fact, a large-scale field reconfigurable array. Taking the advantage of convenience to modify the system, construction of driving circuit, digital signal processing module, network communication interface, control algorithm validation, and remote reconfigurable module may realize. With the concept of integrated hardware and software, the paper discusses the key technology of building scientific CCD system suitable for the special work environment in Antarctica, focusing on the method of remote reconfiguration for controller via network and then offering a feasible hardware and software solution.

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.

Lessions learned in WISE image quality

NASA Astrophysics Data System (ADS)

Kendall, Martha; Duval, Valerie G.; Larsen, Mark F.; Heinrichsen, Ingolf H.; Esplin, Roy W.; Shannon, Mark; Wright, Edward L.

2010-08-01

The Wide-Field Infrared Survey Explorer (WISE) mission launched in December of 2009 is a true success story. The mission is performing beyond expectations on-orbit and maintained cost and schedule throughout. How does such a thing happen? A team constantly focused on mission success is a key factor. Mission success is more than a program meeting its ultimate science goals; it is also meeting schedule and cost goals to avoid cancellation. The WISE program can attribute some of its success in achieving the image quality needed to meet science goals to lessons learned along the way. A requirement was missed in early decomposition, the absence of which would have adversely affected end-to-end system image quality. Fortunately, the ability of the cross-organizational team to focus on fixing the problem without pointing fingers or waiting for paperwork was crucial in achieving a timely solution. Asking layman questions early in the program could have revealed requirement flowdown misunderstandings between spacecraft control stability and image processing needs. Such is the lesson learned with the WISE spacecraft Attitude Determination & Control Subsystem (ADCS) jitter control and the image data reductions needs. Spacecraft motion can affect image quality in numerous ways. Something as seemingly benign as different terminology being used by teammates in separate groups working on data reduction, spacecraft ADCS, the instrument, mission operations, and the science proved to be a risk to system image quality. While the spacecraft was meeting the allocated jitter requirement , the drift rate variation need was not being met. This missing need was noticed about a year before launch and with a dedicated team effort, an adjustment was made to the spacecraft ADCS control. WISE is meeting all image quality requirements on-orbit thanks to a diligent team noticing something was missing before it was too late and applying their best effort to find a solution.

The Importance of Quality in Ventilation-Perfusion Imaging.

PubMed

Mann, April; DiDea, Mario; Fournier, France; Tempesta, Daniel; Williams, Jessica; LaFrance, Norman

2018-06-01

As the health care environment continues to change and morph into a system focusing on increased quality and evidence-based outcomes, nuclear medicine technologists must be reminded that they play a critical role in achieving high-quality, interpretable images used to drive patient care, treatment, and best possible outcomes. A survey performed by the Quality Committee of the Society of Nuclear Medicine and Molecular Imaging Technologist Section demonstrated that a clear knowledge gap exists among technologists regarding their understanding of quality, how it is measured, and how it should be achieved by all practicing technologists regardless of role and education level. Understanding of these areas within health care, in conjunction with the growing emphasis on evidence-based outcomes, quality measures, and patient satisfaction, will ultimately elevate the role of nuclear medicine technologists today and into the future. The nuclear medicine role now requires technologists to demonstrate patient assessment skills, practice safety procedures with regard to staff and patients, provide patient education and instruction, and provide physicians with information to assist with the interpretation and outcome of the study. In addition, the technologist must be able to evaluate images by performing technical analysis, knowing the demonstrated anatomy and pathophysiology, and assessing overall quality. Technologists must also be able to triage and understand the disease processes being evaluated and how nuclear medicine diagnostic studies may drive care and treatment. Therefore, it is imperative that nuclear medicine technologists understand their role in the achievement of a high-quality, interpretable study by applying quality principles and understanding and using imaging techniques beyond just basic protocols for every type of disease or system being imaged. This article focuses on quality considerations related to ventilation-perfusion imaging. It provides insight on

Automated image quality assessment for chest CT scans.

PubMed

Reeves, Anthony P; Xie, Yiting; Liu, Shuang

2018-02-01

Medical image quality needs to be maintained at standards sufficient for effective clinical reading. Automated computer analytic methods may be applied to medical images for quality assessment. For chest CT scans in a lung cancer screening context, an automated quality assessment method is presented that characterizes image noise and image intensity calibration. This is achieved by image measurements in three automatically segmented homogeneous regions of the scan: external air, trachea lumen air, and descending aorta blood. Profiles of CT scanner behavior are also computed. The method has been evaluated on both phantom and real low-dose chest CT scans and results show that repeatable noise and calibration measures may be realized by automated computer algorithms. Noise and calibration profiles show relevant differences between different scanners and protocols. Automated image quality assessment may be useful for quality control for lung cancer screening and may enable performance improvements to automated computer analysis methods. © 2017 American Association of Physicists in Medicine.

Measuring the Flatness of Focal Plane for Very Large Mosaic CCD Camera

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

Hao, Jiangang; Estrada, Juan; Cease, Herman

2010-06-08

Large mosaic multiCCD camera is the key instrument for modern digital sky survey. DECam is an extremely red sensitive 520 Megapixel camera designed for the incoming Dark Energy Survey (DES). It is consist of sixty two 4k x 2k and twelve 2k x 2k 250-micron thick fully-depleted CCDs, with a focal plane of 44 cm in diameter and a field of view of 2.2 square degree. It will be attached to the Blanco 4-meter telescope at CTIO. The DES will cover 5000 square-degrees of the southern galactic cap in 5 color bands (g, r, i, z, Y) in 5 yearsmore » starting from 2011. To achieve the science goal of constraining the Dark Energy evolution, stringent requirements are laid down for the design of DECam. Among them, the flatness of the focal plane needs to be controlled within a 60-micron envelope in order to achieve the specified PSF variation limit. It is very challenging to measure the flatness of the focal plane to such precision when it is placed in a high vacuum dewar at 173 K. We developed two image based techniques to measure the flatness of the focal plane. By imaging a regular grid of dots on the focal plane, the CCD offset along the optical axis is converted to the variation the grid spacings at different positions on the focal plane. After extracting the patterns and comparing the change in spacings, we can measure the flatness to high precision. In method 1, the regular dots are kept in high sub micron precision and cover the whole focal plane. In method 2, no high precision for the grid is required. Instead, we use a precise XY stage moves the pattern across the whole focal plane and comparing the variations of the spacing when it is imaged by different CCDs. Simulation and real measurements show that the two methods work very well for our purpose, and are in good agreement with the direct optical measurements.« less

A novel x-ray imaging system and its imaging performance

NASA Astrophysics Data System (ADS)

Yu, Chunyu; Chang, Benkang; Wang, Shiyun; Zhang, Junju; Yao, Xiao

2006-09-01

Since x-ray was discovered and applied to the imaging technology, the x-ray imaging techniques have experienced several improvements, from film-screen, x-ray image intensifier, CR to DR. To store and transmit the image information conveniently, the digital imaging is necessary for the imaging techniques in medicine and biology. Usually as the intensifying screen technique as for concerned, to get the digital image signals, the CCD was lens coupled directly to the screen, but which suffers from a loss of x-ray signal and resulted in the poor x-ray image perfonnance. Therefore, to improve the image performance, we joined the brightness intensifier, which, was named the Low Light Level (LLL) image intensifier in military affairs, between the intensifying screen and the CCD and designed the novel x-ray imaging system. This design method improved the image performance of the whole system thus decreased the x-ray dose. Comparison between two systems with and without the brightness intensifier was given in detail in this paper. Moreover, the main noise source of the image produced by the novel system was analyzed, and in this paper, the original images produced by the novel x-ray imaging system and the processed images were given respectively. It was clear that the image performance was satisfied and the x-ray imaging system can be used in security checking and many other nondestructive checking fields.

Optical CT scanning of PRESAGETM polyurethane samples with a CCD-based readout system

NASA Astrophysics Data System (ADS)

Doran, S. J.; Krstajic, N.; Adamovics, J.; Jenneson, P. M.

2004-01-01

This article demonstrates the resolution capabilities of the CCD scanner under ideal circumstances and describes the first CCD-based optical CT experiments on a new class of dosimeter, known as PRESAGETM (Heuris Pharma, Skillman, NJ).

Online detecting system of roller wear based on laser-linear array CCD technology

NASA Astrophysics Data System (ADS)

Guo, Yuan

2010-10-01

Roller is an important metallurgy tool in the rolling mill. And the surface of a roller affects the quantity of the rolling product directly. After using a period of time, roller must be repaired or replaced. Examining the profile of a working roller between the intervals of rolling is called online detecting for roller wear. The study of online detecting roller wear is very important for selecting the grinding time in reason, reducing the exchanging times of rollers, improving the quality of the product and realizing online grinding rollers. By applying the laser-linear array CCD detective technology, a method for online non-touch detecting roller wear was brought forward. The principle, composition and the operation process of the linear array CCD detecting system were expatiated. And an error compensation algorithm is exactly calculated to offset the shift of the roller axis in this measurement system. So the stability and the accuracy were improved remarkably. The experiment proves that the accuracy of the detecting system reaches to the demand of practical production process. It can provide a new method of high speed and high accuracy online detecting for roller wear.

Reduced reference image quality assessment via sub-image similarity based redundancy measurement

NASA Astrophysics Data System (ADS)

Mou, Xuanqin; Xue, Wufeng; Zhang, Lei

2012-03-01

The reduced reference (RR) image quality assessment (IQA) has been attracting much attention from researchers for its loyalty to human perception and flexibility in practice. A promising RR metric should be able to predict the perceptual quality of an image accurately while using as few features as possible. In this paper, a novel RR metric is presented, whose novelty lies in two aspects. Firstly, it measures the image redundancy by calculating the so-called Sub-image Similarity (SIS), and the image quality is measured by comparing the SIS between the reference image and the test image. Secondly, the SIS is computed by the ratios of NSE (Non-shift Edge) between pairs of sub-images. Experiments on two IQA databases (i.e. LIVE and CSIQ databases) show that by using only 6 features, the proposed metric can work very well with high correlations between the subjective and objective scores. In particular, it works consistently well across all the distortion types.

Design on the x-ray oral digital image display card

NASA Astrophysics Data System (ADS)

Wang, Liping; Gu, Guohua; Chen, Qian

2009-10-01

According to the main characteristics of X-ray imaging, the X-ray display card is successfully designed and debugged using the basic principle of correlated double sampling (CDS) and combined with embedded computer technology. CCD sensor drive circuit and the corresponding procedures have been designed. Filtering and sampling hold circuit have been designed. The data exchange with PC104 bus has been implemented. Using complex programmable logic device as a device to provide gating and timing logic, the functions which counting, reading CPU control instructions, corresponding exposure and controlling sample-and-hold have been completed. According to the image effect and noise analysis, the circuit components have been adjusted. And high-quality images have been obtained.

CCD detector development projects by the Beamline Technical Support Group at the Advanced Photon Source

NASA Astrophysics Data System (ADS)

Lee, John H.; Fernandez, Patricia; Madden, Tim; Molitsky, Michael; Weizeorick, John

2007-11-01

This paper will describe two ongoing detector projects being developed by the Beamline Technical Support Group at the Advanced Photon Source (APS) at Argonne National Laboratory (ANL). The first project is the design and construction of two detectors: a single-CCD system and a two-by-two Mosaic CCD camera for Small-Angle X-ray Scattering (SAXS). Both of these systems utilize the Kodak KAF-4320E CCD coupled to fiber optic tapers, custom mechanical hardware, electronics, and software developed at ANL. The second project is a Fast-CCD (FCCD) detector being developed in a collaboration between ANL and Lawrence Berkeley National Laboratory (LBNL). This detector will use ANL-designed readout electronics and a custom LBNL-designed CCD, with 480×480 pixels and 96 outputs, giving very fast readout.

Effects of biomechanical forces on signaling in the cortical collecting duct (CCD)

PubMed Central

Carrisoza-Gaytan, Rolando; Liu, Yu; Flores, Daniel; Else, Cindy; Lee, Heon Goo; Rhodes, George; Sandoval, Ruben M.; Kleyman, Thomas R.; Lee, Francis Young-In; Molitoris, Bruce; Satlin, Lisa M.

2014-01-01

An increase in tubular fluid flow rate (TFF) stimulates Na reabsorption and K secretion in the cortical collecting duct (CCD) and subjects cells therein to biomechanical forces including fluid shear stress (FSS) and circumferential stretch (CS). Intracellular MAPK and extracellular autocrine/paracrine PGE2 signaling regulate cation transport in the CCD and, at least in other systems, are affected by biomechanical forces. We hypothesized that FSS and CS differentially affect MAPK signaling and PGE2 release to modulate cation transport in the CCD. To validate that CS is a physiological force in vivo, we applied the intravital microscopic approach to rodent kidneys in vivo to show that saline or furosemide injection led to a 46.5 ± 2.0 or 170 ± 32% increase, respectively, in distal tubular diameter. Next, murine CCD (mpkCCD) cells were grown on glass or silicone coated with collagen type IV and subjected to 0 or 0.4 dyne/cm2 of FSS or 10% CS, respectively, forces chosen based on prior biomechanical modeling of ex vivo microperfused CCDs. Cells exposed to FSS expressed an approximately twofold greater abundance of phospho(p)-ERK and p-p38 vs. static cells, while CS did not alter p-p38 and p-ERK expression compared with unstretched controls. FSS induced whereas CS reduced PGE2 release by ∼40%. In conclusion, FSS and CS differentially affect ERK and p38 activation and PGE2 release in a cell culture model of the CD. We speculate that TFF differentially regulates biomechanical signaling and, in turn, cation transport in the CCD. PMID:24872319

Effects of biomechanical forces on signaling in the cortical collecting duct (CCD).

PubMed

Carrisoza-Gaytan, Rolando; Liu, Yu; Flores, Daniel; Else, Cindy; Lee, Heon Goo; Rhodes, George; Sandoval, Ruben M; Kleyman, Thomas R; Lee, Francis Young-In; Molitoris, Bruce; Satlin, Lisa M; Rohatgi, Rajeev

2014-07-15

An increase in tubular fluid flow rate (TFF) stimulates Na reabsorption and K secretion in the cortical collecting duct (CCD) and subjects cells therein to biomechanical forces including fluid shear stress (FSS) and circumferential stretch (CS). Intracellular MAPK and extracellular autocrine/paracrine PGE2 signaling regulate cation transport in the CCD and, at least in other systems, are affected by biomechanical forces. We hypothesized that FSS and CS differentially affect MAPK signaling and PGE2 release to modulate cation transport in the CCD. To validate that CS is a physiological force in vivo, we applied the intravital microscopic approach to rodent kidneys in vivo to show that saline or furosemide injection led to a 46.5 ± 2.0 or 170 ± 32% increase, respectively, in distal tubular diameter. Next, murine CCD (mpkCCD) cells were grown on glass or silicone coated with collagen type IV and subjected to 0 or 0.4 dyne/cm(2) of FSS or 10% CS, respectively, forces chosen based on prior biomechanical modeling of ex vivo microperfused CCDs. Cells exposed to FSS expressed an approximately twofold greater abundance of phospho(p)-ERK and p-p38 vs. static cells, while CS did not alter p-p38 and p-ERK expression compared with unstretched controls. FSS induced whereas CS reduced PGE2 release by ∼40%. In conclusion, FSS and CS differentially affect ERK and p38 activation and PGE2 release in a cell culture model of the CD. We speculate that TFF differentially regulates biomechanical signaling and, in turn, cation transport in the CCD. Copyright © 2014 the American Physiological Society.

Noise Estimation and Quality Assessment of Gaussian Noise Corrupted Images

NASA Astrophysics Data System (ADS)

Kamble, V. M.; Bhurchandi, K.

2018-03-01

Evaluating the exact quantity of noise present in an image and quality of an image in the absence of reference image is a challenging task. We propose a near perfect noise estimation method and a no reference image quality assessment method for images corrupted by Gaussian noise. The proposed methods obtain initial estimate of noise standard deviation present in an image using the median of wavelet transform coefficients and then obtains a near to exact estimate using curve fitting. The proposed noise estimation method provides the estimate of noise within average error of +/-4%. For quality assessment, this noise estimate is mapped to fit the Differential Mean Opinion Score (DMOS) using a nonlinear function. The proposed methods require minimum training and yields the noise estimate and image quality score. Images from Laboratory for image and Video Processing (LIVE) database and Computational Perception and Image Quality (CSIQ) database are used for validation of the proposed quality assessment method. Experimental results show that the performance of proposed quality assessment method is at par with the existing no reference image quality assessment metric for Gaussian noise corrupted images.

Documentation to the 2015-16 Common Core of Data (CCD) Universe Files. NCES 2017-074

ERIC Educational Resources Information Center

Glander, Mark

2017-01-01

The Common Core of Data (CCD) is a national statistical program that collects and compiles administrative data from SEAs covering the universe of all public elementary and secondary schools and school districts in the United States. The first CCD collection was for SY 1986-87. The predecessor to CCD was the Elementary and Secondary General…

Image quality metrics for volumetric laser displays

NASA Astrophysics Data System (ADS)

Williams, Rodney D.; Donohoo, Daniel

1991-08-01

This paper addresses the extensions to the image quality metrics and related human factors research that are needed to establish the baseline standards for emerging volume display technologies. The existing and recently developed technologies for multiplanar volume displays are reviewed with an emphasis on basic human visual issues. Human factors image quality metrics and guidelines are needed to firmly establish this technology in the marketplace. The human visual requirements and the display design tradeoffs for these prototype laser-based volume displays are addressed and several critical image quality issues identified for further research. The American National Standard for Human Factors Engineering of Visual Display Terminal Workstations (ANSIHFS-100) and other international standards (ISO, DIN) can serve as a starting point, but this research base must be extended to provide new image quality metrics for this new technology for volume displays.

Image Quality Assessment of High-Resolution Satellite Images with Mtf-Based Fuzzy Comprehensive Evaluation Method

NASA Astrophysics Data System (ADS)

Wu, Z.; Luo, Z.; Zhang, Y.; Guo, F.; He, L.

2018-04-01

A Modulation Transfer Function (MTF)-based fuzzy comprehensive evaluation method was proposed in this paper for the purpose of evaluating high-resolution satellite image quality. To establish the factor set, two MTF features and seven radiant features were extracted from the knife-edge region of image patch, which included Nyquist, MTF0.5, entropy, peak signal to noise ratio (PSNR), average difference, edge intensity, average gradient, contrast and ground spatial distance (GSD). After analyzing the statistical distribution of above features, a fuzzy evaluation threshold table and fuzzy evaluation membership functions was established. The experiments for comprehensive quality assessment of different natural and artificial objects was done with GF2 image patches. The results showed that the calibration field image has the highest quality scores. The water image has closest image quality to the calibration field, quality of building image is a little poor than water image, but much higher than farmland image. In order to test the influence of different features on quality evaluation, the experiment with different weights were tested on GF2 and SPOT7 images. The results showed that different weights correspond different evaluating effectiveness. In the case of setting up the weights of edge features and GSD, the image quality of GF2 is better than SPOT7. However, when setting MTF and PSNR as main factor, the image quality of SPOT7 is better than GF2.

Cartographic quality of ERTS-1 images

NASA Technical Reports Server (NTRS)

Welch, R. I.

1973-01-01

Analyses of simulated and operational ERTS images have provided initial estimates of resolution, ground resolution, detectability thresholds and other measures of image quality of interest to earth scientists and cartographers. Based on these values, including an approximate ground resolution of 250 meters for both RBV and MSS systems, the ERTS-1 images appear suited to the production and/or revision of planimetric and photo maps of 1:500,000 scale and smaller for which map accuracy standards are compatible with the imaged detail. Thematic mapping, although less constrained by map accuracy standards, will be influenced by measurement thresholds and errors which have yet to be accurately determined for ERTS images. This study also indicates the desirability of establishing a quantitative relationship between image quality values and map products which will permit both engineers and cartographers/earth scientists to contribute to the design requirements of future satellite imaging systems.

High-throughput Raman chemical imaging for evaluating food safety and quality

NASA Astrophysics Data System (ADS)

Qin, Jianwei; Chao, Kuanglin; Kim, Moon S.

2014-05-01

A line-scan hyperspectral system was developed to enable Raman chemical imaging for large sample areas. A custom-designed 785 nm line-laser based on a scanning mirror serves as an excitation source. A 45° dichroic beamsplitter reflects the laser light to form a 24 cm x 1 mm excitation line normally incident on the sample surface. Raman signals along the laser line are collected by a detection module consisting of a dispersive imaging spectrograph and a CCD camera. A hypercube is accumulated line by line as a motorized table moves the samples transversely through the laser line. The system covers a Raman shift range of -648.7-2889.0 cm-1 and a 23 cm wide area. An example application, for authenticating milk powder, was presented to demonstrate the system performance. In four minutes, the system acquired a 512x110x1024 hypercube (56,320 spectra) from four 47-mm-diameter Petri dishes containing four powder samples. Chemical images were created for detecting two adulterants (melamine and dicyandiamide) that had been mixed into the milk powder.

A CMOS In-Pixel CTIA High Sensitivity Fluorescence Imager.

PubMed

Murari, Kartikeya; Etienne-Cummings, Ralph; Thakor, Nitish; Cauwenberghs, Gert

2011-10-01

Traditionally, charge coupled device (CCD) based image sensors have held sway over the field of biomedical imaging. Complementary metal oxide semiconductor (CMOS) based imagers so far lack sensitivity leading to poor low-light imaging. Certain applications including our work on animal-mountable systems for imaging in awake and unrestrained rodents require the high sensitivity and image quality of CCDs and the low power consumption, flexibility and compactness of CMOS imagers. We present a 132×124 high sensitivity imager array with a 20.1 μm pixel pitch fabricated in a standard 0.5 μ CMOS process. The chip incorporates n-well/p-sub photodiodes, capacitive transimpedance amplifier (CTIA) based in-pixel amplification, pixel scanners and delta differencing circuits. The 5-transistor all-nMOS pixel interfaces with peripheral pMOS transistors for column-parallel CTIA. At 70 fps, the array has a minimum detectable signal of 4 nW/cm(2) at a wavelength of 450 nm while consuming 718 μA from a 3.3 V supply. Peak signal to noise ratio (SNR) was 44 dB at an incident intensity of 1 μW/cm(2). Implementing 4×4 binning allowed the frame rate to be increased to 675 fps. Alternately, sensitivity could be increased to detect about 0.8 nW/cm(2) while maintaining 70 fps. The chip was used to image single cell fluorescence at 28 fps with an average SNR of 32 dB. For comparison, a cooled CCD camera imaged the same cell at 20 fps with an average SNR of 33.2 dB under the same illumination while consuming over a watt.

A CMOS In-Pixel CTIA High Sensitivity Fluorescence Imager

PubMed Central

Murari, Kartikeya; Etienne-Cummings, Ralph; Thakor, Nitish; Cauwenberghs, Gert

2012-01-01

Traditionally, charge coupled device (CCD) based image sensors have held sway over the field of biomedical imaging. Complementary metal oxide semiconductor (CMOS) based imagers so far lack sensitivity leading to poor low-light imaging. Certain applications including our work on animal-mountable systems for imaging in awake and unrestrained rodents require the high sensitivity and image quality of CCDs and the low power consumption, flexibility and compactness of CMOS imagers. We present a 132×124 high sensitivity imager array with a 20.1 μm pixel pitch fabricated in a standard 0.5 μ CMOS process. The chip incorporates n-well/p-sub photodiodes, capacitive transimpedance amplifier (CTIA) based in-pixel amplification, pixel scanners and delta differencing circuits. The 5-transistor all-nMOS pixel interfaces with peripheral pMOS transistors for column-parallel CTIA. At 70 fps, the array has a minimum detectable signal of 4 nW/cm2 at a wavelength of 450 nm while consuming 718 μA from a 3.3 V supply. Peak signal to noise ratio (SNR) was 44 dB at an incident intensity of 1 μW/cm2. Implementing 4×4 binning allowed the frame rate to be increased to 675 fps. Alternately, sensitivity could be increased to detect about 0.8 nW/cm2 while maintaining 70 fps. The chip was used to image single cell fluorescence at 28 fps with an average SNR of 32 dB. For comparison, a cooled CCD camera imaged the same cell at 20 fps with an average SNR of 33.2 dB under the same illumination while consuming over a watt. PMID:23136624

Influence of reconstruction algorithms on image quality in SPECT myocardial perfusion imaging.

PubMed

Davidsson, Anette; Olsson, Eva; Engvall, Jan; Gustafsson, Agnetha

2017-11-01

We investigated if image- and diagnostic quality in SPECT MPI could be maintained despite a reduced acquisition time adding Depth Dependent Resolution Recovery (DDRR) for image reconstruction. Images were compared with filtered back projection (FBP) and iterative reconstruction using Ordered Subsets Expectation Maximization with (IRAC) and without (IRNC) attenuation correction (AC). Stress- and rest imaging for 15 min was performed on 21 subjects with a dual head gamma camera (Infinia Hawkeye; GE Healthcare), ECG-gating with 8 frames/cardiac cycle and a low-dose CT-scan. A 9 min acquisition was generated using five instead of eight gated frames and was reconstructed with DDRR, with (IRACRR) and without AC (IRNCRR) as well as with FBP. Three experienced nuclear medicine specialists visually assessed anonymized images according to eight criteria on a four point scale, three related to image quality and five to diagnostic confidence. Statistical analysis was performed using Visual Grading Regression (VGR). Observer confidence in statements on image quality was highest for the images that were reconstructed using DDRR (P<0·01 compared to FBP). Iterative reconstruction without DDRR was not superior to FBP. Interobserver variability was significant for statements on image quality (P<0·05) but lower in the diagnostic statements on ischemia and scar. The confidence in assessing ischemia and scar was not different between the reconstruction techniques (P = n.s.). SPECT MPI collected in 9 min, reconstructed with DDRR and AC, produced better image quality than the standard procedure. The observers expressed the highest diagnostic confidence in the DDRR reconstruction. © 2016 Scandinavian Society of Clinical Physiology and Nuclear Medicine. Published by John Wiley & Sons Ltd.

Image gathering and restoration - Information and visual quality

NASA Technical Reports Server (NTRS)

Mccormick, Judith A.; Alter-Gartenberg, Rachel; Huck, Friedrich O.

1989-01-01

A method is investigated for optimizing the end-to-end performance of image gathering and restoration for visual quality. To achieve this objective, one must inevitably confront the problems that the visual quality of restored images depends on perceptual rather than mathematical considerations and that these considerations vary with the target, the application, and the observer. The method adopted in this paper is to optimize image gathering informationally and to restore images interactively to obtain the visually preferred trade-off among fidelity resolution, sharpness, and clarity. The results demonstrate that this method leads to significant improvements in the visual quality obtained by the traditional digital processing methods. These traditional methods allow a significant loss of visual quality to occur because they treat the design of the image-gathering system and the formulation of the image-restoration algorithm as two separate tasks and fail to account for the transformations between the continuous and the discrete representations in image gathering and reconstruction.

Southern Clusters for Standardizing CCD Photometry

NASA Astrophysics Data System (ADS)

Moon, T. T.

2017-06-01

Standardizing photometric measurements typically involves undertaking all-sky photometry. This can be laborious and time-consuming and, for CCD photometry, particularly challenging. Transforming photometry to a standard system is, however, a crucial step when routinely measuring variable stars, as it allows photoelectric measurements from different observers to be combined. For observers in the northern hemisphere, standardized UBVRI values of stars in open clusters such as M67 and NGC 7790 have been established, greatly facilitating quick and accurate transformation of CCD measurements. Recently the AAVSO added the cluster NGC 3532 for southern hemisphere observers to similarly standardize their photometry. The availability of NGC 3532 standards was announced on the AAVSO Variable Star Observing, Photometry forum on 27 October 2016. Published photometry, along with some new measurements by the author, provide a means of checking these NGC 3532 standards which were determined through the AAVSO's Bright Star Monitor (BSM) program (see: https://www.aavso.org/aavsonet-epoch-photometry-database). New measurements of selected stars in the open clusters M25 and NGC 6067 are also included.

Consequences of CCD imperfections for cosmology determined by weak lensing surveys: from laboratory measurements to cosmological parameter bias

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

Okura, Yuki; Petri, Andrea; May, Morgan

Weak gravitational lensing causes subtle changes in the apparent shapes of galaxies due to the bending of light by the gravity of foreground masses. By measuring the shapes of large numbers of galaxies (millions in recent surveys, up to tens of billions in future surveys) we can infer the parameters that determine cosmology. Imperfections in the detectors used to record images of the sky can introduce changes in the apparent shape of galaxies, which in turn can bias the inferred cosmological parameters. Here in this paper we consider the effect of two widely discussed sensor imperfections: tree-rings, due to impuritymore » gradients which cause transverse electric fields in the Charge-Coupled Devices (CCD), and pixel-size variation, due to periodic CCD fabrication errors. These imperfections can be observed when the detectors are subject to uniform illumination (flat field images). We develop methods to determine the spurious shear and convergence (due to the imperfections) from the flat-field images. We calculate how the spurious shear when added to the lensing shear will bias the determination of cosmological parameters. We apply our methods to candidate sensors of the Large Synoptic Survey Telescope (LSST) as a timely and important example, analyzing flat field images recorded with LSST prototype CCDs in the laboratory. In conclusion, we find that tree-rings and periodic pixel-size variation present in the LSST CCDs will introduce negligible bias to cosmological parameters determined from the lensing power spectrum, specifically w,Ω m and σ 8.« less

Consequences of CCD imperfections for cosmology determined by weak lensing surveys: from laboratory measurements to cosmological parameter bias

DOE PAGES

Okura, Yuki; Petri, Andrea; May, Morgan; ...

2016-06-27

Weak gravitational lensing causes subtle changes in the apparent shapes of galaxies due to the bending of light by the gravity of foreground masses. By measuring the shapes of large numbers of galaxies (millions in recent surveys, up to tens of billions in future surveys) we can infer the parameters that determine cosmology. Imperfections in the detectors used to record images of the sky can introduce changes in the apparent shape of galaxies, which in turn can bias the inferred cosmological parameters. Here in this paper we consider the effect of two widely discussed sensor imperfections: tree-rings, due to impuritymore » gradients which cause transverse electric fields in the Charge-Coupled Devices (CCD), and pixel-size variation, due to periodic CCD fabrication errors. These imperfections can be observed when the detectors are subject to uniform illumination (flat field images). We develop methods to determine the spurious shear and convergence (due to the imperfections) from the flat-field images. We calculate how the spurious shear when added to the lensing shear will bias the determination of cosmological parameters. We apply our methods to candidate sensors of the Large Synoptic Survey Telescope (LSST) as a timely and important example, analyzing flat field images recorded with LSST prototype CCDs in the laboratory. In conclusion, we find that tree-rings and periodic pixel-size variation present in the LSST CCDs will introduce negligible bias to cosmological parameters determined from the lensing power spectrum, specifically w,Ω m and σ 8.« less

The effect of image quality and forensic expertise in facial image comparisons.

PubMed

Norell, Kristin; Läthén, Klas Brorsson; Bergström, Peter; Rice, Allyson; Natu, Vaidehi; O'Toole, Alice

2015-03-01

Images of perpetrators in surveillance video footage are often used as evidence in court. In this study, identification accuracy was compared for forensic experts and untrained persons in facial image comparisons as well as the impact of image quality. Participants viewed thirty image pairs and were asked to rate the level of support garnered from their observations for concluding whether or not the two images showed the same person. Forensic experts reached their conclusions with significantly fewer errors than did untrained participants. They were also better than novices at determining when two high-quality images depicted the same person. Notably, lower image quality led to more careful conclusions by experts, but not for untrained participants. In summary, the untrained participants had more false negatives and false positives than experts, which in the latter case could lead to a higher risk of an innocent person being convicted for an untrained witness. © 2014 American Academy of Forensic Sciences.

An FPGA-based heterogeneous image fusion system design method

NASA Astrophysics Data System (ADS)

Song, Le; Lin, Yu-chi; Chen, Yan-hua; Zhao, Mei-rong

2011-08-01

Taking the advantages of FPGA's low cost and compact structure, an FPGA-based heterogeneous image fusion platform is established in this study. Altera's Cyclone IV series FPGA is adopted as the core processor of the platform, and the visible light CCD camera and infrared thermal imager are used as the image-capturing device in order to obtain dualchannel heterogeneous video images. Tailor-made image fusion algorithms such as gray-scale weighted averaging, maximum selection and minimum selection methods are analyzed and compared. VHDL language and the synchronous design method are utilized to perform a reliable RTL-level description. Altera's Quartus II 9.0 software is applied to simulate and implement the algorithm modules. The contrast experiments of various fusion algorithms show that, preferably image quality of the heterogeneous image fusion can be obtained on top of the proposed system. The applied range of the different fusion algorithms is also discussed.

Blind image quality assessment without training on human opinion scores

NASA Astrophysics Data System (ADS)

Mittal, Anish; Soundararajan, Rajiv; Muralidhar, Gautam S.; Bovik, Alan C.; Ghosh, Joydeep

2013-03-01

We propose a family of image quality assessment (IQA) models based on natural scene statistics (NSS), that can predict the subjective quality of a distorted image without reference to a corresponding distortionless image, and without any training results on human opinion scores of distorted images. These `completely blind' models compete well with standard non-blind image quality indices in terms of subjective predictive performance when tested on the large publicly available `LIVE' Image Quality database.

Quality measures in applications of image restoration.

PubMed

Kriete, A; Naim, M; Schafer, L

2001-01-01

We describe a new method for the estimation of image quality in image restoration applications. We demonstrate this technique on a simulated data set of fluorescent beads, in comparison with restoration by three different deconvolution methods. Both the number of iterations and a regularisation factor are varied to enforce changes in the resulting image quality. First, the data sets are directly compared by an accuracy measure. These values serve to validate the image quality descriptor, which is developed on the basis of optical information theory. This most general measure takes into account the spectral energies and the noise, weighted in a logarithmic fashion. It is demonstrated that this method is particularly helpful as a user-oriented method to control the output of iterative image restorations and to eliminate the guesswork in choosing a suitable number of iterations.

Image quality classification for DR screening using deep learning.

PubMed

FengLi Yu; Jing Sun; Annan Li; Jun Cheng; Cheng Wan; Jiang Liu

2017-07-01

The quality of input images significantly affects the outcome of automated diabetic retinopathy (DR) screening systems. Unlike the previous methods that only consider simple low-level features such as hand-crafted geometric and structural features, in this paper we propose a novel method for retinal image quality classification (IQC) that performs computational algorithms imitating the working of the human visual system. The proposed algorithm combines unsupervised features from saliency map and supervised features coming from convolutional neural networks (CNN), which are fed to an SVM to automatically detect high quality vs poor quality retinal fundus images. We demonstrate the superior performance of our proposed algorithm on a large retinal fundus image dataset and the method could achieve higher accuracy than other methods. Although retinal images are used in this study, the methodology is applicable to the image quality assessment and enhancement of other types of medical images.

Quantum efficiency measurement of the Transiting Exoplanet Survey Satellite (TESS) CCD detectors

NASA Astrophysics Data System (ADS)

Krishnamurthy, A.; Villasenor, J.; Thayer, C.; Kissel, S.; Ricker, G.; Seager, S.; Lyle, R.; Deline, A.; Morgan, E.; Sauerwein, T.; Vanderspek, R.

2016-07-01

Very precise on-ground characterization and calibration of TESS CCD detectors will significantly assist in the analysis of the science data from the mission. An accurate optical test bench with very high photometric stability has been developed to perform precise measurements of the absolute quantum efficiency. The setup consists of a vacuum dewar with a single MIT Lincoln Lab CCID-80 device mounted on a cold plate with the calibrated reference photodiode mounted next to the CCD. A very stable laser-driven light source is integrated with a closed-loop intensity stabilization unit to control variations of the light source down to a few parts-per-million when averaged over 60 s. Light from the stabilization unit enters a 20 inch integrating sphere. The output light from the sphere produces near-uniform illumination on the cold CCD and on the calibrated reference photodiode inside the dewar. The ratio of the CCD and photodiode signals provides the absolute quantum efficiency measurement. The design, key features, error analysis, and results from the test campaign are presented.

Eliminating "Hotspots" in Digital Image Processing

NASA Technical Reports Server (NTRS)

Salomon, P. M.

1984-01-01

Signals from defective picture elements rejected. Image processing program for use with charge-coupled device (CCD) or other mosaic imager augmented with algorithm that compensates for common type of electronic defect. Algorithm prevents false interpretation of "hotspots". Used for robotics, image enhancement, image analysis and digital television.

Image aesthetic quality evaluation using convolution neural network embedded learning

NASA Astrophysics Data System (ADS)

Li, Yu-xin; Pu, Yuan-yuan; Xu, Dan; Qian, Wen-hua; Wang, Li-peng

2017-11-01

A way of embedded learning convolution neural network (ELCNN) based on the image content is proposed to evaluate the image aesthetic quality in this paper. Our approach can not only solve the problem of small-scale data but also score the image aesthetic quality. First, we chose Alexnet and VGG_S to compare for confirming which is more suitable for this image aesthetic quality evaluation task. Second, to further boost the image aesthetic quality classification performance, we employ the image content to train aesthetic quality classification models. But the training samples become smaller and only using once fine-tuning cannot make full use of the small-scale data set. Third, to solve the problem in second step, a way of using twice fine-tuning continually based on the aesthetic quality label and content label respective is proposed, the classification probability of the trained CNN models is used to evaluate the image aesthetic quality. The experiments are carried on the small-scale data set of Photo Quality. The experiment results show that the classification accuracy rates of our approach are higher than the existing image aesthetic quality evaluation approaches.

CCD Times of Minima of Selected Eclipsing Binaries

NASA Astrophysics Data System (ADS)

Zejda, Miloslav

2004-12-01

682 CCD minima observations of 259 eclipsing binaries made mainly by author are presented. The observed stars were chosen mainly from catalogue BRKA of observing programme of BRNO-Variable Star Section of CAS.

Multiplexed Oversampling Digitizer in 65 nm CMOS for Column-Parallel CCD Readout

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

Grace, Carl; Walder, Jean-Pierre; von der Lippe, Henrik

2012-04-10

A digitizer designed to read out column-parallel charge-coupled devices (CCDs) used for high-speed X-ray imaging is presented. The digitizer is included as part of the High-Speed Image Preprocessor with Oversampling (HIPPO) integrated circuit. The digitizer module comprises a multiplexed, oversampling, 12-bit, 80 MS/s pipelined Analog-to-Digital Converter (ADC) and a bank of four fast-settling sample-and-hold amplifiers to instrument four analog channels. The ADC multiplexes and oversamples to reduce its area to allow integration that is pitch-matched to the columns of the CCD. Novel design techniques are used to enable oversampling and multiplexing with a reduced power penalty. The ADC exhibits 188more » ?V-rms noise which is less than 1 LSB at a 12-bit level. The prototype is implemented in a commercially available 65 nm CMOS process. The digitizer will lead to a proof-of-principle 2D 10 Gigapixel/s X-ray detector.« less

Cross-layer Energy Optimization Under Image Quality Constraints for Wireless Image Transmissions.

PubMed

Yang, Na; Demirkol, Ilker; Heinzelman, Wendi

2012-01-01

Wireless image transmission is critical in many applications, such as surveillance and environment monitoring. In order to make the best use of the limited energy of the battery-operated cameras, while satisfying the application-level image quality constraints, cross-layer design is critical. In this paper, we develop an image transmission model that allows the application layer (e.g., the user) to specify an image quality constraint, and optimizes the lower layer parameters of transmit power and packet length, to minimize the energy dissipation in image transmission over a given distance. The effectiveness of this approach is evaluated by applying the proposed energy optimization to a reference ZigBee system and a WiFi system, and also by comparing to an energy optimization study that does not consider any image quality constraint. Evaluations show that our scheme outperforms the default settings of the investigated commercial devices and saves a significant amount of energy at middle-to-large transmission distances.

Retinal Image Quality Assessment for Spaceflight-Induced Vision Impairment Study

NASA Technical Reports Server (NTRS)

Vu, Amanda Cadao; Raghunandan, Sneha; Vyas, Ruchi; Radhakrishnan, Krishnan; Taibbi, Giovanni; Vizzeri, Gianmarco; Grant, Maria; Chalam, Kakarla; Parsons-Wingerter, Patricia

2015-01-01

Long-term exposure to space microgravity poses significant risks for visual impairment. Evidence suggests such vision changes are linked to cephalad fluid shifts, prompting a need to directly quantify microgravity-induced retinal vascular changes. The quality of retinal images used for such vascular remodeling analysis, however, is dependent on imaging methodology. For our exploratory study, we hypothesized that retinal images captured using fluorescein imaging methodologies would be of higher quality in comparison to images captured without fluorescein. A semi-automated image quality assessment was developed using Vessel Generation Analysis (VESGEN) software and MATLAB® image analysis toolboxes. An analysis of ten images found that the fluorescein imaging modality provided a 36% increase in overall image quality (two-tailed p=0.089) in comparison to nonfluorescein imaging techniques.

Quality Improvement of Liver Ultrasound Images Using Fuzzy Techniques.

PubMed

Bayani, Azadeh; Langarizadeh, Mostafa; Radmard, Amir Reza; Nejad, Ahmadreza Farzaneh

2016-12-01

Liver ultrasound images are so common and are applied so often to diagnose diffuse liver diseases like fatty liver. However, the low quality of such images makes it difficult to analyze them and diagnose diseases. The purpose of this study, therefore, is to improve the contrast and quality of liver ultrasound images. In this study, a number of image contrast enhancement algorithms which are based on fuzzy logic were applied to liver ultrasound images - in which the view of kidney is observable - using Matlab2013b to improve the image contrast and quality which has a fuzzy definition; just like image contrast improvement algorithms using a fuzzy intensification operator, contrast improvement algorithms applying fuzzy image histogram hyperbolization, and contrast improvement algorithms by fuzzy IF-THEN rules. With the measurement of Mean Squared Error and Peak Signal to Noise Ratio obtained from different images, fuzzy methods provided better results, and their implementation - compared with histogram equalization method - led both to the improvement of contrast and visual quality of images and to the improvement of liver segmentation algorithms results in images. Comparison of the four algorithms revealed the power of fuzzy logic in improving image contrast compared with traditional image processing algorithms. Moreover, contrast improvement algorithm based on a fuzzy intensification operator was selected as the strongest algorithm considering the measured indicators. This method can also be used in future studies on other ultrasound images for quality improvement and other image processing and analysis applications.

Design and laboratory calibration of the compact pushbroom hyperspectral imaging system

NASA Astrophysics Data System (ADS)

Zhou, Jiankang; Ji, Yiqun; Chen, Yuheng; Chen, Xinhua; Shen, Weimin

2009-11-01

The designed hyperspectral imaging system is composed of three main parts, that is, optical subsystem, electronic subsystem and capturing subsystem. And a three-dimensional "image cube" can be obtained through push-broom. The fore-optics is commercial-off-the-shelf with high speed and three continuous zoom ratios. Since the dispersive imaging part is based on Offner relay configuration with an aberration-corrected convex grating, high power of light collection and variable view field are obtained. The holographic recording parameters of the convex grating are optimized, and the aberration of the Offner configuration dispersive system is balanced. The electronic system adopts module design, which can minimize size, mass, and power consumption. Frame transfer area-array CCD is chosen as the image sensor and the spectral line can be binned to achieve better SNR and sensitivity without any deterioration in spatial resolution. The capturing system based on the computer can set the capturing parameters, calibrate the spectrometer, process and display spectral imaging data. Laboratory calibrations are prerequisite for using precise spectral data. The spatial and spectral calibration minimize smile and keystone distortion caused by optical system, assembly and so on and fix positions of spatial and spectral line on the frame area-array CCD. Gases excitation lamp is used in smile calibration and the keystone calculation is carried out by different viewing field point source created by a series of narrow slit. The laboratory and field imaging results show that this pushbroom hyperspectral imaging system can acquire high quality spectral images.

Accelerated wavefront determination technique for optical imaging through scattering medium

NASA Astrophysics Data System (ADS)

He, Hexiang; Wong, Kam Sing

2016-03-01

Wavefront shaping applied on scattering light is a promising optical imaging method in biological systems. Normally, optimized modulation can be obtained by a Liquid-Crystal Spatial Light Modulator (LC-SLM) and CCD hardware iteration. Here we introduce an improved method for this optimization process. The core of the proposed method is to firstly detect the disturbed wavefront, and then to calculate the modulation phase pattern by computer simulation. In particular, phase retrieval method together with phase conjugation is most effective. In this way, the LC-SLM based system can complete the wavefront optimization and imaging restoration within several seconds which is two orders of magnitude faster than the conventional technique. The experimental results show good imaging quality and may contribute to real time imaging recovery in scattering medium.

Measured and calculated K-fluorescence effects on the MTF of an amorphous-selenium based CCD x-ray detector.

PubMed

Hunter, David M; Belev, George; Kasap, Safa; Yaffe, Martin J

2012-02-01

Theoretical reasoning suggests that direct conversion digital x-ray detectors based upon photoconductive amorphous-selenium (a-Se) could attain very high values of the MTF (modulation transfer function) at spatial frequencies well beyond 20 cycles mm(-1). One of the fundamental factors affecting resolution loss, particularly at x-ray energies just above the K-edge of selenium (12.66 keV), is the K-fluorescence reabsorption mechanism, wherein energy can be deposited in the detector at locations laterally displaced from the initial x-ray interaction site. This paper compares measured MTF changes above and below the Se K-edge of a CCD based a-Se x-ray detector with theoretical expectations. A prototype 25 μm sampling pitch (Nyquist frequency = 20 cycles mm(-1), 200 μm thick a-Se layer based x-ray detector, utilizing a specialized CCD readout device (200 × 400 area array), was used to make edge images with monochromatic x-rays above and below the K-edge of Se. A vacuum double crystal monochromator, exposed to polychromatic x-rays from a synchrotron, formed the monochromatic x-ray source. The monochromaticity of the x-rays was 99% or better. The presampling MTF was determined using the slanted edge method. The theory modeling the MTF performance of the detector includes the basic x-ray interaction physics in the a-Se layer as well as effects related to the operation of the CCD and charge trapping at a blocking layer present at the CCD/a-Se interface. The MTF performance of the prototype a-Se CCD was reduced from the theoretical value prescribed by the basic Se x-ray interaction physics, principally by the presence of a blocking layer. Nevertheless, the K-fluorescence reduction in the MTF was observed, approximately as predicted by theory. For the CCD prototype detector, at five cycles mm(-1), there was a 14% reduction of the MTF, from a value of 0.7 below the K-edge of Se, to 0.6 just above the K-edge. The MTF of an a-Se x-ray detector has been measured using

Experimental research on thermal conductive fillers for CCD module in space borne optical remote sensor

NASA Astrophysics Data System (ADS)

Zeng, Yi; Han, Xue-bing; Yang, Dong-shang; Gui, Li-jia; Zhao, Xiao-xiang; Si, Fu-qi

2016-03-01

A space-borne differential optical absorption spectrometer is a high precision aerospace optical remote sensor. It obtains the hyper-spectral，high spatial resolution radiation information by using the spectrometer with CCD（Charge Coupled Device）array detectors. Since a few CCDs are used as the key detector, the performance of the entire instrument is greatly affected by working condition of CCDs. The temperature of CCD modules has a great impact on the instrument measurement accuracy. It requires strict temperature control. The selection of the thermal conductive filler sticking CCD to the radiator is important in the CCD thermal design. Besides，due tothe complex and compact structure, it needs to take into account the anti-pollution of the optical system. Therefore, it puts forward high requirements on the selection of the conductive filler. In this paper, according to the structure characteristics of the CCD modules and the distribution of heat consumption, the thermal analysis tool I-DEAS/TMG is utilized to compute and simulate the temperature level of the CCD modules, while filling in thermal grease and thermal pad respectively. The temperature distribution of CCD heat dissipation in typical operating conditions is obtained. In addition, the heat balance test was carried out under the condition of two kinds of thermal conductive fillers. The thermal control of CCD was tested under various conditions, and the results were compared with the results of thermal analysis. The results show that there are some differences in thermal performance between the two kinds of thermal conductive fillers. Although they both can meet the thermal performance requirements of the instrument, either would be chosen taking account of other conditions and requirements such as anti-pollution and insulation. The content and results of this paper will be a good reference for the thermal design of the CCD in the aerospace optical payload.

A Real-Time Position-Locating Algorithm for CCD-Based Sunspot Tracking

NASA Technical Reports Server (NTRS)

Taylor, Jaime R.

1996-01-01

NASA Marshall Space Flight Center's (MSFC) EXperimental Vector Magnetograph (EXVM) polarimeter measures the sun's vector magnetic field. These measurements are taken to improve understanding of the sun's magnetic field in the hopes to better predict solar flares. Part of the procedure for the EXVM requires image motion stabilization over a period of a few minutes. A high speed tracker can be used to reduce image motion produced by wind loading on the EXVM, fluctuations in the atmosphere and other vibrations. The tracker consists of two elements, an image motion detector and a control system. The image motion detector determines the image movement from one frame to the next and sends an error signal to the control system. For the ground based application to reduce image motion due to atmospheric fluctuations requires an error determination at the rate of at least 100 hz. It would be desirable to have an error determination rate of 1 kHz to assure that higher rate image motion is reduced and to increase the control system stability. Two algorithms are presented that are typically used for tracking. These algorithms are examined for their applicability for tracking sunspots, specifically their accuracy if only one column and one row of CCD pixels are used. To examine the accuracy of this method two techniques are used. One involves moving a sunspot image a known distance with computer software, then applying the particular algorithm to see how accurately it determines this movement. The second technique involves using a rate table to control the object motion, then applying the algorithms to see how accurately each determines the actual motion. Results from these two techniques are presented.

New Research by CCD Scanning for Comets and Asteroids

NASA Technical Reports Server (NTRS)

Gehrels, Tom

1997-01-01

Spacewatch was begun in 1980; its purpose is to explore the various populations of small objects within the solar system. Spacewatch provides data for studies of comets and asteroids, finds potential targets for space missions, and provides information on the environmental problem of possible impacts. Moving objects are discovered by scanning the sky with charge-coupled devices (CCDS) on the 0.9-meter Spacewatch Telescope of the University of Arizona on Kitt Peak. Each Spacewatch scan consists of three drift scan passes over an area of sky using a CCD filtered to a bandpass of 0.5-1.0 pm (approximately V+R+I with peak sensitivity at 0.7 pm). The effective exposure time for each pass is 143 seconds multiplied by the secant of the declination. The area covered by each scan is 32 arcminutes in declination by about 28 minutes of time in right ascension. The image scale is 1.05 arcseconds per pixel. Three passes take about 1.5 hours to complete and show motions of individual objects over a one hour time baseline. The limiting magnitude is about 21.5 in single scans. CCD scanning was developed by Spacewatch in the early 1980s, with improvements still being made - particularly by bringing a new 1.8-m Spacewatch Telescope on line. In the meantime, we have been finding some 30,000 new asteroids per year and applying their statistics to the study of the collisional history of the solar system. Spacewatch had found a total of 150 Near-Earth Asteroids (NEAS) and 8 new comets, and had recovered one lost comet (P/Spitaler in 1993). Spacewatch is also efficient in recovery of known comets and has detected and reported positions for more than 137,000 asteroids, mostly new ones in the main belt, including more than 10,882 asteroids designated by the Minor Planet Center (MPC).

Quality evaluation of no-reference MR images using multidirectional filters and image statistics.

PubMed

Jang, Jinseong; Bang, Kihun; Jang, Hanbyol; Hwang, Dosik

2018-09-01

This study aimed to develop a fully automatic, no-reference image-quality assessment (IQA) method for MR images. New quality-aware features were obtained by applying multidirectional filters to MR images and examining the feature statistics. A histogram of these features was then fitted to a generalized Gaussian distribution function for which the shape parameters yielded different values depending on the type of distortion in the MR image. Standard feature statistics were established through a training process based on high-quality MR images without distortion. Subsequently, the feature statistics of a test MR image were calculated and compared with the standards. The quality score was calculated as the difference between the shape parameters of the test image and the undistorted standard images. The proposed IQA method showed a >0.99 correlation with the conventional full-reference assessment methods; accordingly, this proposed method yielded the best performance among no-reference IQA methods for images containing six types of synthetic, MR-specific distortions. In addition, for authentically distorted images, the proposed method yielded the highest correlation with subjective assessments by human observers, thus demonstrating its superior performance over other no-reference IQAs. Our proposed IQA was designed to consider MR-specific features and outperformed other no-reference IQAs designed mainly for photographic images. Magn Reson Med 80:914-924, 2018. © 2018 International Society for Magnetic Resonance in Medicine. © 2018 International Society for Magnetic Resonance in Medicine.

Validation of no-reference image quality index for the assessment of digital mammographic images

NASA Astrophysics Data System (ADS)

de Oliveira, Helder C. R.; Barufaldi, Bruno; Borges, Lucas R.; Gabarda, Salvador; Bakic, Predrag R.; Maidment, Andrew D. A.; Schiabel, Homero; Vieira, Marcelo A. C.

2016-03-01

To ensure optimal clinical performance of digital mammography, it is necessary to obtain images with high spatial resolution and low noise, keeping radiation exposure as low as possible. These requirements directly affect the interpretation of radiologists. The quality of a digital image should be assessed using objective measurements. In general, these methods measure the similarity between a degraded image and an ideal image without degradation (ground-truth), used as a reference. These methods are called Full-Reference Image Quality Assessment (FR-IQA). However, for digital mammography, an image without degradation is not available in clinical practice; thus, an objective method to assess the quality of mammograms must be performed without reference. The purpose of this study is to present a Normalized Anisotropic Quality Index (NAQI), based on the Rényi entropy in the pseudo-Wigner domain, to assess mammography images in terms of spatial resolution and noise without any reference. The method was validated using synthetic images acquired through an anthropomorphic breast software phantom, and the clinical exposures on anthropomorphic breast physical phantoms and patient's mammograms. The results reported by this noreference index follow the same behavior as other well-established full-reference metrics, e.g., the peak signal-to-noise ratio (PSNR) and structural similarity index (SSIM). Reductions of 50% on the radiation dose in phantom images were translated as a decrease of 4dB on the PSNR, 25% on the SSIM and 33% on the NAQI, evidencing that the proposed metric is sensitive to the noise resulted from dose reduction. The clinical results showed that images reduced to 53% and 30% of the standard radiation dose reported reductions of 15% and 25% on the NAQI, respectively. Thus, this index may be used in clinical practice as an image quality indicator to improve the quality assurance programs in mammography; hence, the proposed method reduces the subjectivity

A novel imaging method for photonic crystal fiber fusion splicer

NASA Astrophysics Data System (ADS)

Bi, Weihong; Fu, Guangwei; Guo, Xuan

2007-01-01

Because the structure of Photonic Crystal Fiber (PCF) is very complex, and it is very difficult that traditional fiber fusion splice obtains optical axial information of PCF. Therefore, we must search for a bran-new optical imaging method to get section information of Photonic Crystal Fiber. Based on complex trait of PCF, a novel high-precision optics imaging system is presented in this article. The system uses a thinned electron-bombarded CCD (EBCCD) which is a kind of image sensor as imaging element, the thinned electron-bombarded CCD can offer low light level performance superior to conventional image intensifier coupled CCD approaches, this high-performance device can provide high contrast high resolution in low light level surveillance imaging; in order to realize precision focusing of image, we use a ultra-highprecision pace motor to adjust position of imaging lens. In this way, we can obtain legible section information of PCF. We may realize further concrete analysis for section information of PCF by digital image processing technology. Using this section information may distinguish different sorts of PCF, compute some parameters such as the size of PCF ventage, cladding structure of PCF and so on, and provide necessary analysis data for PCF fixation, adjustment, regulation, fusion and cutting system.

Theodolite with CCD Camera for Safe Measurement of Laser-Beam Pointing

NASA Technical Reports Server (NTRS)

Crooke, Julie A.

2003-01-01

The simple addition of a charge-coupled-device (CCD) camera to a theodolite makes it safe to measure the pointing direction of a laser beam. The present state of the art requires this to be a custom addition because theodolites are manufactured without CCD cameras as standard or even optional equipment. A theodolite is an alignment telescope equipped with mechanisms to measure the azimuth and elevation angles to the sub-arcsecond level. When measuring the angular pointing direction of a Class ll laser with a theodolite, one could place a calculated amount of neutral density (ND) filters in front of the theodolite s telescope. One could then safely view and measure the laser s boresight looking through the theodolite s telescope without great risk to one s eyes. This method for a Class ll visible wavelength laser is not acceptable to even consider tempting for a Class IV laser and not applicable for an infrared (IR) laser. If one chooses insufficient attenuation or forgets to use the filters, then looking at the laser beam through the theodolite could cause instant blindness. The CCD camera is already commercially available. It is a small, inexpensive, blackand- white CCD circuit-board-level camera. An interface adaptor was designed and fabricated to mount the camera onto the eyepiece of the specific theodolite s viewing telescope. Other equipment needed for operation of the camera are power supplies, cables, and a black-and-white television monitor. The picture displayed on the monitor is equivalent to what one would see when looking directly through the theodolite. Again, the additional advantage afforded by a cheap black-and-white CCD camera is that it is sensitive to infrared as well as to visible light. Hence, one can use the camera coupled to a theodolite to measure the pointing of an infrared as well as a visible laser.

Quality Improvement of Liver Ultrasound Images Using Fuzzy Techniques