Performance of 4x5120 Element Visible and 2x2560 Element Shortwave Infrared Multispectral Focal Planes

NASA Astrophysics Data System (ADS)

Tower, J. R.; Cope, A. D.; Pellion, L. E.; McCarthy, B. M.; Strong, R. T.; Kinnard, K. F.; Moldovan, A. G.; Levine, P. A.; Elabd, H.; Hoffman, D. M.

1985-12-01

Performance measurements of two Multispectral Linear Array focal planes are presented. Both pushbroom sensors have been developed for application in remote sensing instruments. A buttable, four-spectral-band, linear-format charge coupled device (CCD) and a but-table, two-spectral-band, linear-format, shortwave infrared charge coupled device (IRCCD) have been developed under NASA funding. These silicon integrated circuits may be butted end to end to provide very-high-resolution multispectral focal planes. The visible CCD is organized as four sensor lines of 1024 pixels each. Each line views the scene in a different spectral window defined by integral optical bandpass filters. A prototype focal plane with five devices, providing 4x5120-pixel resolution has been demonstrated. The high quantum efficiency of the backside-illuminated CCD technology provides excellent signal-to-noise performance and unusually high MTF across the entire visible and near-IR spectrum. The shortwave infrared (SWIR) sensor is organized as two line sensors of 512 detectors each. The SWIR (1-2.5 μm) spectral windows may be defined by bandpass filters placed in close proximity to the devices. The dual-band sensor consists of Schottky barrier detectors read out by CCD multiplexers. This monolithic sensor operates at 125°K with radiometric performance. A prototype five-device focal plane providing 2x2560 detectors has been demonstrated. The devices provide very high uniformity, and excellent MTF across the SWIR band.

NASA-Texas Planetary Program

NASA Technical Reports Server (NTRS)

Smith, H. J.

1984-01-01

Astronomical observations performed at the McDonald Observatory were summarized. Various spectra obtained from Jupiter, Uranus, Saturn, Neptune, Pluto, Titan, Iapetus, and sundry asteroids were described briefly. Spectra taken of various comets using an IDS (Intensified Dissector Scanner) spectrograph on a 2.7 m telescope were reviewed. The Octicon, a linear array of eight 1872-element Reticon arrays that was installed in the 2.7 m coude spectrograph at the observatory, was described. The 2.7 m coude scanner, 2.7 m coude CCD (charge coupled device), and 2.7 m radial velocity spectrometer were mentioned.

Signal detectability in diffusive media using phased arrays in conjunction with detector arrays.

PubMed

Kang, Dongyel; Kupinski, Matthew A

2011-06-20

We investigate Hotelling observer performance (i.e., signal detectability) of a phased array system for tasks of detecting small inhomogeneities and distinguishing adjacent abnormalities in uniform diffusive media. Unlike conventional phased array systems where a single detector is located on the interface between two sources, we consider a detector array, such as a CCD, on a phantom exit surface for calculating the Hotelling observer detectability. The signal detectability for adjacent small abnormalities (2 mm displacement) for the CCD-based phased array is related to the resolution of reconstructed images. Simulations show that acquiring high-dimensional data from a detector array in a phased array system dramatically improves the detectability for both tasks when compared to conventional single detector measurements, especially at low modulation frequencies. It is also observed in all studied cases that there exists the modulation frequency optimizing CCD-based phased array systems, where detectability for both tasks is consistently high. These results imply that the CCD-based phased array has the potential to achieve high resolution and signal detectability in tomographic diffusive imaging while operating at a very low modulation frequency. The effect of other configuration parameters, such as a detector pixel size, on the observer performance is also discussed.

Design and fabrication of an angle-scanning based platform for the construction of surface plasmon resonance biosensor

NASA Astrophysics Data System (ADS)

Hu, Jiandong; Cao, Baiqiong; Wang, Shun; Li, Jianwei; Wei, Wensong; Zhao, Yuanyuan; Hu, Xinran; Zhu, Juanhua; Jiang, Min; Sun, Xiaohui; Chen, Ruipeng; Ma, Liuzheng

2016-03-01

A sensing system for an angle-scanning optical surface-plasmon-resonance (SPR) based biosensor has been designed with a laser line generator in which a P polarizer is embedded to utilize as an excitation source for producing the surface plasmon wave. In this system, the emitting beam from the laser line generator is controlled to realize the angle-scanning using a variable speed direct current (DC) motor. The light beam reflected from the prism deposited with a 50 nm Au film is then captured using the area CCD array which was controlled by a personal computer (PC) via a universal serial bus (USB) interface. The photoelectric signals from the high speed digital camera (an area CCD array) were converted by a 16 bit A/D converter before it transferred to the PC. One of the advantages of this SPR biosensing platform is greatly demonstrated by the label-free and real-time bio-molecular analysis without moving the area CCD array by following the laser line generator. It also could provide a low-cost surface plasmon resonance platform to improve the detection range in the measurement of bioanalytes. The SPR curve displayed on the PC screen promptly is formed by the effective data from the image on the area CCD array and the sensing responses of the platform to bulk refractive indices were calibrated using various concentrations of ethanol solution. These ethanol concentrations indicated with volumetric fraction of 5%, 10%, 15%, 20%, and 25%, respectively, were experimented to validate the performance of the angle-scanning optic SPR biosensing platform. As a result, the SPR sensor was capable to detect a change in the refractive index of the ethanol solution with the relative high linearity at the correlation coefficient of 0.9842. This greatly enhanced detection range is obtained from the position relationship between the laser line generator and the right-angle prism to allow direct quantification of the samples over a wide range of concentrations.

Design of area array CCD image acquisition and display system based on FPGA

NASA Astrophysics Data System (ADS)

Li, Lei; Zhang, Ning; Li, Tianting; Pan, Yue; Dai, Yuming

2014-09-01

With the development of science and technology, CCD(Charge-coupled Device) has been widely applied in various fields and plays an important role in the modern sensing system, therefore researching a real-time image acquisition and display plan based on CCD device has great significance. This paper introduces an image data acquisition and display system of area array CCD based on FPGA. Several key technical challenges and problems of the system have also been analyzed and followed solutions put forward .The FPGA works as the core processing unit in the system that controls the integral time sequence .The ICX285AL area array CCD image sensor produced by SONY Corporation has been used in the system. The FPGA works to complete the driver of the area array CCD, then analog front end (AFE) processes the signal of the CCD image, including amplification, filtering, noise elimination, CDS correlation double sampling, etc. AD9945 produced by ADI Corporation to convert analog signal to digital signal. Developed Camera Link high-speed data transmission circuit, and completed the PC-end software design of the image acquisition, and realized the real-time display of images. The result through practical testing indicates that the system in the image acquisition and control is stable and reliable, and the indicators meet the actual project requirements.

Research on detecting heterogeneous fibre from cotton based on linear CCD camera

NASA Astrophysics Data System (ADS)

Zhang, Xian-bin; Cao, Bing; Zhang, Xin-peng; Shi, Wei

2009-07-01

The heterogeneous fibre in cotton make a great impact on production of cotton textile, it will have a bad effect on the quality of product, thereby affect economic benefits and market competitive ability of corporation. So the detecting and eliminating of heterogeneous fibre is particular important to improve machining technics of cotton, advance the quality of cotton textile and reduce production cost. There are favorable market value and future development for this technology. An optical detecting system obtains the widespread application. In this system, we use a linear CCD camera to scan the running cotton, then the video signals are put into computer and processed according to the difference of grayscale, if there is heterogeneous fibre in cotton, the computer will send an order to drive the gas nozzle to eliminate the heterogeneous fibre. In the paper, we adopt monochrome LED array as the new detecting light source, it's lamp flicker, stability of luminous intensity, lumens depreciation and useful life are all superior to fluorescence light. We analyse the reflection spectrum of cotton and various heterogeneous fibre first, then select appropriate frequency of the light source, we finally adopt violet LED array as the new detecting light source. The whole hardware structure and software design are introduced in this paper.

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.

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.

A novel approach of an absolute coding pattern based on Hamiltonian graph

NASA Astrophysics Data System (ADS)

Wang, Ya'nan; Wang, Huawei; Hao, Fusheng; Liu, Liqiang

2017-02-01

In this paper, a novel approach of an optical type absolute rotary encoder coding pattern is presented. The concept is based on the principle of the absolute encoder to find out a unique sequence that ensures an unambiguous shaft position of any angular. We design a single-ring and a n-by-2 matrix absolute encoder coding pattern by using the variations of Hamiltonian graph principle. 12 encoding bits is used in the single-ring by a linear array CCD to achieve an 1080-position cycle encoding. Besides, a 2-by-2 matrix is used as an unit in the 2-track disk to achieve a 16-bits encoding pattern by using an area array CCD sensor (as a sample). Finally, a higher resolution can be gained by an electronic subdivision of the signals. Compared with the conventional gray or binary code pattern (for a 2n resolution), this new pattern has a higher resolution (2n*n) with less coding tracks, which means the new pattern can lead to a smaller encoder, which is essential in the industrial production.

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.

InSb arrays with CCD readout for 1.0- to 5.5-microns infrared applications

NASA Technical Reports Server (NTRS)

Phillips, J. D.; Scorso, J. B.; Thom, R. D.

1976-01-01

There were two approaches for fabricating indium antimonide (InSb) arrays with CCD readout discussed. The hybrid approach integrated InSb detectors and silicon CCDs in a modular assembly via an advanced interconnection technology. In the monolithic approach, the InSb infrared detectors and the CCD readout were integrated on the same InSb chip. Both approaches utilized intrinsic (band-to-band) photodetection with the attendant advantages over extrinsic detectors. The status of each of these detector readout concepts, with pertinent performance characteristics, was presented.

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.

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.

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.

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).

Improvement in the light sensitivity of the ultrahigh-speed high-sensitivity CCD with a microlens array

NASA Astrophysics Data System (ADS)

Hayashida, T.,; Yonai, J.; Kitamura, K.; Arai, T.; Kurita, T.; Tanioka, K.; Maruyama, H.; Etoh, T. Goji; Kitagawa, S.; Hatade, K.; Yamaguchi, T.; Takeuchi, H.; Iida, K.

2008-02-01

We are advancing the development of ultrahigh-speed, high-sensitivity CCDs for broadcast use that are capable of capturing smooth slow-motion videos in vivid colors even where lighting is limited, such as at professional baseball games played at night. We have already developed a 300,000 pixel, ultrahigh-speed CCD, and a single CCD color camera that has been used for sports broadcasts and science programs using this CCD. However, there are cases where even higher sensitivity is required, such as when using a telephoto lens during a baseball broadcast or a high-magnification microscope during science programs. This paper provides a summary of our experimental development aimed at further increasing the sensitivity of CCDs using the light-collecting effects of a microlens array.

High-resolution CCD imaging alternatives

NASA Astrophysics Data System (ADS)

Brown, D. L.; Acker, D. E.

1992-08-01

High resolution CCD color cameras have recently stimulated the interest of a large number of potential end-users for a wide range of practical applications. Real-time High Definition Television (HDTV) systems are now being used or considered for use in applications ranging from entertainment program origination through digital image storage to medical and scientific research. HDTV generation of electronic images offers significant cost and time-saving advantages over the use of film in such applications. Further in still image systems electronic image capture is faster and more efficient than conventional image scanners. The CCD still camera can capture 3-dimensional objects into the computing environment directly without having to shoot a picture on film develop it and then scan the image into a computer. 2. EXTENDING CCD TECHNOLOGY BEYOND BROADCAST Most standard production CCD sensor chips are made for broadcast-compatible systems. One popular CCD and the basis for this discussion offers arrays of roughly 750 x 580 picture elements (pixels) or a total array of approximately 435 pixels (see Fig. 1). FOR. A has developed a technique to increase the number of available pixels for a given image compared to that produced by the standard CCD itself. Using an inter-lined CCD with an overall spatial structure several times larger than the photo-sensitive sensor areas each of the CCD sensors is shifted in two dimensions in order to fill in spatial gaps between adjacent sensors.

Characterization of Custom-Designed Charge-Coupled Devices for Applications to Gas and Aerosol Monitoring Sensorcraft Instrument

NASA Technical Reports Server (NTRS)

Refaat, Tamer F.; Abedin, M. Nurul; Farnsworth, Glenn R.; Garcia, Christopher S.; Zawodny, Joseph M.

2005-01-01

Custom-designed charge-coupled devices (CCD) for Gas and Aerosols Monitoring Sensorcraft instrument were developed. These custom-designed CCD devices are linear arrays with pixel format of 512x1 elements and pixel size of 10x200 sq m. These devices were characterized at NASA Langley Research Center to achieve a full well capacity as high as 6,000,000 e-. This met the aircraft flight mission requirements in terms of signal-to-noise performance and maximum dynamic range. Characterization and analysis of the electrical and optical properties of the CCDs were carried out at room temperature. This includes measurements of photon transfer curves, gain coefficient histograms, read noise, and spectral response. Test results obtained on these devices successfully demonstrated the objectives of the aircraft flight mission. In this paper, we describe the characterization results and also discuss their applications to future mission.

Digital solar edge tracker for the Halogen Occultation Experiment

NASA Technical Reports Server (NTRS)

Mauldin, L. E., III; Moore, A. S.; Stump, C. W.; Mayo, L. S.

1987-01-01

The optical and electronic design of the Halogen Occultation Experiment (Haloe) elevation sun sensor is described. The Haloe instrument is a gas-correlation radiometer now being developed at NASA Langley for the Upper Atmosphere Research Satellite. The system uses a Galilean telescope to form a solar image on a linear silicon photodiode array. The array is a self-scanned monolithic CCD. The addresses of both solar edges imaged on the array are used by the control/pointing system to scan the Haloe science instantaneous field of view (IFOV) across the vertical solar diameter during instrument calibration and then to maintain the science IFOV 4 arcmin below the top edge during the science data occultation event. Vertical resolution of 16 arcsec and a radiometric dynamic range of 100 are achieved at the 700-nm operating wavelength. The design provides for loss of individual photodiode elements without loss of angular tracking capability.

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.

Nonlinear optical cryptosystem based on joint Fresnel transform correlator under vector wave illumination

NASA Astrophysics Data System (ADS)

Xueju, Shen; Chao, Lin; Xiao, Zou; Jianjun, Cai

2015-05-01

We present a nonlinear optical cryptosystem with multi-dimensional keys including phase, polarization and diffraction distance. To make full use of the degrees of freedom that optical processing offers, an elaborately designed vector wave with both a space-variant phase and locally linear polarization is generated with a common-path interferometer for illumination. The joint transform correlator in the Fresnel domain, implemented with a double optical wedge, is utilized as the encryption framework which provides an additional key known as the Fresnel diffraction distance. Two nonlinear operations imposed on the recorded joint Fresnel power distribution (JFPD) by a charge coupled device (CCD) are adopted. The first one is the division of power distribution of the reference window random function which is previously proposed by researchers and can improve the quality of the decrypted image. The second one is the recording of a hybrid JFPD using a micro-polarizers array with orthogonal and random transmissive axes attached to the CCD. Then the hybrid JFPD is further scrambled by substituting random noise for partial power distribution. The two nonlinear operations break the linearity of this cryptosystem and provide ultra security. We verify our proposal using a quick response code for noise-free recovery.

On a photon-counting array using the Fairchild CCD-201

NASA Technical Reports Server (NTRS)

Currie, D. G.

1975-01-01

The evaluation of certain performance parameters of the Fairchild CCD 201 and the proposed method of operation of an electron bombarded charge coupled device are described. Work in progress on the evaluation of the parameters relevant to remote, low noise operation is reported. These tests have been conducted using light input. The video data from the CCD are amplified, digitized, stored in a minicomputer memory, and then recorded on magnetic tape for analyzing. The device will be used in an array of sensors in the aperture plane of a telescope to discriminate between photoelectron events, and in the focal plane operating at single photoelectron sensitivity at a minimum of blooming and lag.

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.

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.

Development of nine-channel 10-micrometer (Hg, Cd)Te pushbroom IR/CCD system

NASA Technical Reports Server (NTRS)

White, W. J.; Wasa, S.

1977-01-01

The engineering development of the 9-channel detector array is documented. The development of the array demonstrates the feasibility of a self scanned multi-element infrared detector focal plane. Procedures for operating the array are outlined.

MOS Circuitry Would Detect Low-Energy Charged Particles

NASA Technical Reports Server (NTRS)

Sinha, Mahadeva; Wadsworth, Mark

2003-01-01

Metal oxide semiconductor (MOS) circuits for measuring spatially varying intensities of beams of low-energy charged particles have been developed. These circuits are intended especially for use in measuring fluxes of ions with spatial resolution along the focal planes of mass spectrometers. Unlike prior mass spectrometer focal-plane detectors, these MOS circuits would not be based on ion-induced generation of electrons, and photons; instead, they would be based on direct detection of the electric charges of the ions. Hence, there would be no need for microchannel plates (for ion-to-electron conversion), phosphors (for electron-to-photon conversion), and photodetectors (for final detection) -- components that degrade spatial resolution and contribute to complexity and size. The developmental circuits are based on linear arrays of charge-coupled devices (CCDs) with associated readout circuitry (see figure). They resemble linear CCD photodetector arrays, except that instead of a photodetector, each pixel contains a capacitive charge sensor. The capacitor in each sensor comprises two electrodes (typically made of aluminum) separated by a layer of insulating material. The exposed electrode captures ions and accumulates their electric charges during signal-integration periods.

[A capillary blood flow velocity detection system based on linear array charge-coupled devices].

PubMed

Zhou, Houming; Wang, Ruofeng; Dang, Qi; Yang, Li; Wang, Xiang

2017-12-01

In order to detect the flow characteristics of blood samples in the capillary, this paper introduces a blood flow velocity measurement system based on field-programmable gate array (FPGA), linear charge-coupled devices (CCD) and personal computer (PC) software structure. Based on the analysis of the TCD1703C and AD9826 device data sheets, Verilog HDL hardware description language was used to design and simulate the driver. Image signal acquisition and the extraction of the real-time edge information of the blood sample were carried out synchronously in the FPGA. Then a series of discrete displacement were performed in a differential operation to scan each of the blood samples displacement, so that the sample flow rate could be obtained. Finally, the feasibility of the blood flow velocity detection system was verified by simulation and debugging. After drawing the flow velocity curve and analyzing the velocity characteristics, the significance of measuring blood flow velocity is analyzed. The results show that the measurement of the system is less time-consuming and less complex than other flow rate monitoring schemes.

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.

The OCA CCD Camera Controller

DTIC Science & Technology

1996-01-01

multi CCD arrays for wide field telescopes with an array of 8x8 1K CCDs in use at Las Campanas Observatory in Chile . The same group is also involved...Verify key EPROM -292H VIH . VIH Program security bitl 1 29AH . VPP Program security’ bit 2 *. .298H -Vpp Verify security bits - 9HVIH ViI NOTE: 1...Pulsed from V.. to VIL and returned to VIH . EPROM PROGRAMMING AND VERIFICATION ..t= 21’C to-+27 ’rC:-VCC= 5V ±10%VS3 = OV. SYMBOL I .-- PARAMETER MIN MAX

VizieR Online Data Catalog: MYStIX: the Chandra X-ray sources (Kuhn+, 2013)

NASA Astrophysics Data System (ADS)

Kuhn, M. A.; Getman, K. V.; Broos, P. S.; Townsley, L. K.; Feigelson, E. D.

2013-11-01

X-ray observations were made with the imaging array on the Advanced CCD Imaging Spectrometer (ACIS-I) on board the Chandra X-Ray Observatory. This array of four CCD detectors subtends 17'x17' on the sky. Data were acquired from the Chandra Data Archive from 2001 Jan to Mar 2008 for 10 MYStIX fields (Flame Nebula, RCW 36, NGC 2264, Rosette Nebula, Lagoon Nebula, NGC 2362, DR 21, RCW 38, Trifid Nebula and NGC 1893); see table1. (2 data files).

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 meter. The resistance values between clock signal lines are measured. Contrasting the resistance values of the CCD before and after damage, it is found that the resistances decrease significantly between the vertical transfer clock signal lines values. The same results are found between the vertical transfer clock signal line and the earth electrode (ground).At last, the damage position and the damage mechanism were analyzed with above results and SEM morphological experiments. The point damage results in the laser destroying material, which shows no macro electro influence. The line damage is quite different from that of point damage, which shows deeper material corroding effect. More importantly, short circuits are found between vertical clock lines. The full array damage is even more severe than that of line damage starring with SEM, while no obvious different electrical features than that of line damage are found. Further researches are anticipated in femto second laser caused CCD damage mechanism with more advanced tools. This research is valuable in EO countermeasure and/or laser shielding applications.

A 14-bit 40-MHz analog front end for CCD application

NASA Astrophysics Data System (ADS)

Jingyu, Wang; Zhangming, Zhu; Shubin, Liu

2016-06-01

A 14-bit, 40-MHz analog front end (AFE) for CCD scanners is analyzed and designed. The proposed system incorporates a digitally controlled wideband variable gain amplifier (VGA) with nearly 42 dB gain range, a correlated double sampler (CDS) with programmable gain functionality, a 14-bit analog-to-digital converter and a programmable timing core. To achieve the maximum dynamic range, the VGA proposed here can linearly amplify the input signal in a gain range from -1.08 to 41.06 dB in 6.02 dB step with a constant bandwidth. A novel CDS takes image information out of noise, and further amplifies the signal accurately in a gain range from 0 to 18 dB in 0.035 dB step. A 14-bit ADC is adopted to quantify the analog signal with optimization in power and linearity. An internal timing core can provide flexible timing for CCD arrays, CDS and ADC. The proposed AFE was fabricated in SMIC 0.18 μm CMOS process. The whole circuit occupied an active area of 2.8 × 4.8 mm2 and consumed 360 mW. When the frequency of input signal is 6.069 MHz, and the sampling frequency is 40 MHz, the signal to noise and distortion (SNDR) is 70.3 dB, the effective number of bits is 11.39 bit. Project supported by the National Natural Science Foundation of China (Nos. 61234002, 61322405, 61306044, 61376033), the National High-Tech Program of China (No. 2013AA014103), and the Opening Project of Science and Technology on Reliability Physics and Application Technology of Electronic Component Laboratory (No. ZHD201302).

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

Lynch, Bart D.; Kozelka, Jakub; Ranade, Manisha K.

In this study, we present three significant artifacts that have the potential to negatively impact the accuracy and precision of film dosimetry measurements made using GAFCHROMIC[reg] EBT radiochromic film when read out with CCD flatbed scanners. Films were scanned using three commonly employed instruments: a Macbeth TD932 spot densitometer, an Epson Expression 1680 CCD array scanner, and a Microtek ScanMaker i900 CCD array scanner. For the two scanners we assessed the variation in optical density (OD) of GAFCHROMIC EBT film with scanning bed position, angular rotation of the film with respect to the scan line direction, and temperature inside themore » scanner due to repeated scanning. Scanning uniform radiochromic films demonstrated a distinct bowing effect in profiles in the direction of the CCD array with a nonuniformity of up to 17%. Profiles along a direction orthogonal to the CCD array demonstrated a 7% variation. A strong angular dependence was found in measurements made with the flatbed scanners; the effect could not be reproduced with the spot densitometer. An IMRT quality assurance film was scanned twice rotating the film 90 deg. between the scans. For films scanned on the Epson scanner, up to 12% variation was observed in unirradiated EBT films rotated between 0 deg. and 90 deg. , which decreased to approximately 8% for EBT films irradiated to 300 cGy. Variations of up to 80% were observed for films scanned with the Microtek scanner. The scanners were found to significantly increase the film temperature with repeated scanning. Film temperature between 18 and 33 deg. C caused OD changes of approximately 7%. Considering these effects, we recommend adherence to a strict scanning protocol that includes: maintaining the orientation of films scanned on flatbed scanners, limiting scanning to the central portion of the scanner bed, and limiting the number of consecutive scans to minimize changes in OD caused by film heating.« less

Assessment study of infrared detector arrays for low-background astronomical research

NASA Technical Reports Server (NTRS)

Ando, K. J.

1978-01-01

The current state-of-the-art of infrared detector arrays employing charge coupled devices (CCD) or charge injection devices (CID) readout are assessed. The applicability, limitations and potentials of such arrays under the low-background astronomical observing conditions of interest for SIRFT (Shuttle Infrared Telescope Facility) are determined. The following are reviewed: (1) monolithic extrinsic arrays; (2) monolithic intrinsic arrays; (3) charge injection devices; and (4) hybrid arrays.

Line scanning system for direct digital chemiluminescence imaging of DNA sequencing blots

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

Karger, A.E.; Weiss, R.; Gesteland, R.F.

A cryogenically cooled charge-coupled device (CCD) camera equipped with an area CCD array is used in a line scanning system for low-light-level imaging of chemiluminescent DNA sequencing blots. Operating the CCD camera in time-delayed integration (TDI) mode results in continuous data acquisition independent of the length of the CCD array. Scanning is possible with a resolution of 1.4 line pairs/mm at the 50% level of the modulation transfer function. High-sensitivity, low-light-level scanning of chemiluminescent direct-transfer electrophoresis (DTE) DNA sequencing blots is shown. The detection of DNA fragments on the blot involves DNA-DNA hybridization with oligonucleotide-alkaline phosphatase conjugate and 1,2-dioxetane-based chemiluminescence.more » The width of the scan allows the recording of up to four sequencing reactions (16 lanes) on one scan. The scan speed of 52 cm/h used for the sequencing blots corresponds to a data acquisition rate of 384 pixels/s. The chemiluminescence detection limit on the scanned images is 3.9 [times] 10[sup [minus]18] mol of plasmid DNA. A conditional median filter is described to remove spikes caused by cosmic ray events from the CCD images. 39 refs., 9 refs.« less

Defect inspection in hot slab surface: multi-source CCD imaging based fuzzy-rough sets method

NASA Astrophysics Data System (ADS)

Zhao, Liming; Zhang, Yi; Xu, Xiaodong; Xiao, Hong; Huang, Chao

2016-09-01

To provide an accurate surface defects inspection method and make the automation of robust image region of interests(ROI) delineation strategy a reality in production line, a multi-source CCD imaging based fuzzy-rough sets method is proposed for hot slab surface quality assessment. The applicability of the presented method and the devised system are mainly tied to the surface quality inspection for strip, billet and slab surface etcetera. In this work we take into account the complementary advantages in two common machine vision (MV) systems(line array CCD traditional scanning imaging (LS-imaging) and area array CCD laser three-dimensional (3D) scanning imaging (AL-imaging)), and through establishing the model of fuzzy-rough sets in the detection system the seeds for relative fuzzy connectedness(RFC) delineation for ROI can placed adaptively, which introduces the upper and lower approximation sets for RIO definition, and by which the boundary region can be delineated by RFC region competitive classification mechanism. For the first time, a Multi-source CCD imaging based fuzzy-rough sets strategy is attempted for CC-slab surface defects inspection that allows an automatic way of AI algorithms and powerful ROI delineation strategies to be applied to the MV inspection field.

64 x 64 thresholding photodetector array for optical pattern recognition

NASA Astrophysics Data System (ADS)

Langenbacher, Harry; Chao, Tien-Hsin; Shaw, Timothy; Yu, Jeffrey W.

1993-10-01

A high performance 32 X 32 peak detector array is introduced. This detector consists of a 32 X 32 array of thresholding photo-transistor cells, manufactured with a standard MOSIS digital 2-micron CMOS process. A built-in thresholding function that is able to perform 1024 thresholding operations in parallel strongly distinguishes this chip from available CCD detectors. This high speed detector offers responses from one to 10 milliseconds that is much higher than the commercially available CCD detectors operating at a TV frame rate. The parallel multiple peaks thresholding detection capability makes it particularly suitable for optical correlator and optoelectronically implemented neural networks. The principle of operation, circuit design and the performance characteristics are described. Experimental demonstration of correlation peak detection is also provided. Recently, we have also designed and built an advanced version of a 64 X 64 thresholding photodetector array chip. Experimental investigation of using this chip for pattern recognition is ongoing.

DQE analysis for CCD imaging arrays

NASA Astrophysics Data System (ADS)

Shaw, Rodney

1997-05-01

By consideration of the statistical interaction between exposure quanta and the mechanisms of image detection, the signal-to-noise limitations of a variety of image acquisition technologies are now well understood. However in spite of the growing fields of application for CCD imaging- arrays and the obvious advantages of their multi-level mode of quantum detection, only limited and largely empirical approaches have been made to quantify these advantages on an absolute basis. Here an extension is made of a previous model for noise-free sequential photon-counting to the more general case involving both count-noise and arbitrary separation functions between count levels. This allows a basic model to be developed for the DQE associated with devices which approximate to the CCD mode of operation, and conclusions to be made concerning the roles of the separation-function and count-noise in defining the departure from the ideal photon counter.

Low-background performance of a monolithic InSb CCD array

NASA Technical Reports Server (NTRS)

Bregman, J. D.; Goebel, J. H.; Mccreight, C. R.; Matsumoto, T.

1982-01-01

A 20 element monolithic InSb charge coupled device (CCD) detector array was measured under low background conditions to assess its potential for orbital astronomical applications. At a temperature of 64 K, previous results for charge transfer efficiency (CTE) were reproduced, and a sensitivity of about 2 x 10 to the minus 15th power joules was measured. At 27 and 6 K, extended integration times were achieved, but CTE was substantially degraded. The noise was approximately 6000 charges, which was in excess of the level where statistical fluctuations from the illumination could be detected. A telescope demonstration was performed showing that the array sensitivity and difficulty of operation were not substantially different from laboratory levels. Ways in which the device could be improved for astronomical applications were discussed.

Construction of a photochemical reactor combining a CCD spectrophotometer and a LED radiation source.

PubMed

Gombár, Melinda; Józsa, Éva; Braun, Mihály; Ősz, Katalin

2012-10-01

An inexpensive photoreactor using LED light sources and a fibre-optic CCD spectrophotometer as a detector was built by designing a special cell holder for standard 1.000 cm cuvettes. The use of this device was demonstrated by studying the aqueous photochemical reaction of 2,5-dichloro-1,4-benzoquinone. The developed method combines the highly quantitative data collection of CCD spectrophotometers with the possibility of illuminating the sample independently of the detecting light beam, which is a substantial improvement of the method using diode array spectrophotometers as photoreactors.

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.

CCD Measurements of Double and Multiple Stars at NAO Rozhen and ASV in 2015

NASA Astrophysics Data System (ADS)

Cvetković, Z.; Pavlović, R.; Boeva, S.

2017-04-01

Results of CCD observations of 154 double or multiple stars, made with the 2 m telescope of the Bulgarian National Astronomical Observatory at Rozhen over five nights in 2015, are presented. This is the ninth series of measurements of CCD frames obtained at Rozhen. We also present results of CCD observations of 323 double or multiple stars made with the 0.6 m telescope of the Serbian Astronomical Station on the mountain of Vidojevica over 23 nights in 2015. This is the fourth series of measurements of CCD frames obtained at this station. This paper contains the results for the position angle and angular separation for 801 pairs and residuals for 127 pairs with published orbital elements or linear solutions. The angular separations are in the range from 1.″52 to 201.″56, with a median angular separation of 8.″26. We also present eight pairs that are measured for the first time and linear elements for five pairs.

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.

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.

Design and performance of 4 x 5120-element visible and 2 x 2560-element shortwave infrared multispectral focal planes

NASA Astrophysics Data System (ADS)

Tower, J. R.; Cope, A. D.; Pellon, L. E.; McCarthy, B. M.; Strong, R. T.

1986-06-01

Two solid-state sensors for use in remote sensing instruments operating in the pushbroom mode are examined. The design and characteristics of the visible/near-infrared (VIS/NIR) device and the short-wavelength infrared (SWIR) device are described. The VIS/NIR is a CCD imager with four parallel sensor lines, each 1024 pixel long; the chip design and filter system of the VIS/NIR are studied. The performance of the VIS/NIR sensor with mask and its system performance are measured. The SWIR is a dual-band line imager consisting of palladium silicide Schottky-barrier detectors coupled to CCD multiplexers; the performance of the device is analyzed. The substrate materials and layout designs used to assemble the 4 x 5120-element VIS/NIR array and the 2 x 2560-element SWIR array are discussed, and the planarity of the butted arrays are verified using a profilometer. The optical and electrical characteristics, and the placement and butting accuracy of the arrays are evaluated. It is noted that the arrays met or exceed their expected performance.

Nonlinear time dependence of dark current in charge-coupled devices

NASA Astrophysics Data System (ADS)

Dunlap, Justin C.; Bodegom, Erik; Widenhorn, Ralf

2011-03-01

It is generally assumed that charge-coupled device (CCD) imagers produce a linear response of dark current versus exposure time except near saturation. We found a large number of pixels with nonlinear dark current response to exposure time to be present in two scientific CCD imagers. These pixels are found to exhibit distinguishable behavior with other analogous pixels and therefore can be characterized in groupings. Data from two Kodak CCD sensors are presented for exposure times from a few seconds up to two hours. Linear behavior is traditionally taken for granted when carrying out dark current correction and as a result, pixels with nonlinear behavior will be corrected inaccurately.

Development of advanced diagnostics for characterization of burning droplets in microgravity

NASA Technical Reports Server (NTRS)

Sankar, Subramanian; Buermann, Dale H.; Bachalo, William D.

1995-01-01

Diagnostic techniques currently used for microgravity research are generally not as advanced as those used in earth based gravity experiments. Diagnostic techniques for measuring the instantaneous radial temperature profile (or temperature gradients) within the burning droplet do not exist. Over the past few years, Aerometrics has been researching and developing a rainbow thermometric technique for measuring the droplet temperatures of burning droplets. This technique has recently been integrated with the phase Doppler interferometric technique to yield a diagnostic instrument that can be used to simultaneously measure the size, velocity, and temperature of burning droplets in complex spray flames. Also, the rainbow thermometric technique has been recently integrated with a point-diffraction interferometric technique for measuring the instantaneous gas phase temperature field surrounding a burning droplet. These research programs, apart from being very successful, have also helped us identify other innovative techniques for the characterization of burning droplets. For example, new techniques have been identified for measuring the instantaneous regression rate of burning droplets. Also, there is the possibility of extracting the instantaneous radial temperature distribution or the temperature gradients within a droplet during transient heating. What is important is that these diagnostic techniques have the potential for making use of inexpensive, light-weight, and rugged devices such as diode lasers and linear CCD arrays. As a result, they can be easily packaged for incorporation into microgravity drop-test and flight-test facilities. Furthermore, with the use of linear CCD arrays, data rates as high as 10-100 kHz can be easily achieved. This data rate is orders of magnitude higher than what is currently achievable. In this research and development program, a compact and rugged diagnostic system will be developed that can be used to measure instantaneous fuel droplet diameter, droplet regression rate, and the droplet internal temperature profiles or gradients at very high data rates in microgravity experiments.

Arecibo Optical Laboratory Upgrade: imaging FPI first results

NASA Astrophysics Data System (ADS)

Noto, J.; Kerr, R. B.; Migliozzi, M. A.; Tepley, C. A.; Friedman, J.; Garcia, R.; Robles, E.; Waldrop, L. S.

2006-05-01

The Optical Laboratory at the Arecibo Observatory is being upgraded to permit remote operation, to improve Fabry-Perot Interferometer (FPI) sensitivity, and to permit FPI response in the near infrared. Integration of a 2048 x 2048 Andor CCD array into the existing low-resolution Fabry Perot Interferometer is complete. Remote operation and data acquisition for this FPI is accomplished by transition from the obsolete PDP-11 data acquisition system to PC-based, internet aware control. Another upgrade stage, adding a near-infrared focal plane array to a second FPI is scheduled for the fall of this year. Configured with a spectral resolution of 0.0086 nm at 656.3 nm, the low resolution FPI sampled the geocoronal Balmer-alpha emission during three new moon periods in November and December, 2005, and January, 2006. The latter two observation campaigns were conducted using the new remote control capability. The single etalon FPI produces three orders at the CCD plane corresponding to a full field-of-view of 0.92 degrees. The FPI Hadinger ring pattern is summed annularly, and the three orders are subsequently summed, producing an instrument sensitivity that is 43 times better than the previous single channel photomultiplier detection system. Raw detector response is corrected using both linear (chip bias) and non-linear techniques (flat-field) prior to ring-summing. A frequency stabilized HeNe laser at 632.8 nm is remotely operated to establish the FPI response function. Effective exospheric temperature and line profile asymmetries are determined after decomposition of the instrument response function from the measured airglow emission. Identification and climatological characterization of non-Maxwellian H distributions, with simultaneous quantification of H+ abundance and flow in the topside ionosphere by the Arecibo incoherent scatter radar, are measurements central to our goal of improved understanding of H on H+ charge exchange escape of H.

[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

Study of optimal wavefront sensing with elongated laser guide stars

NASA Astrophysics Data System (ADS)

Thomas, S. J.; Adkins, S.; Gavel, D.; Fusco, T.; Michau, V.

2008-06-01

Over the past decade, adaptive optics (AO) has become an established method for overcoming the effects of atmospheric turbulence on both astronomical imaging and spectroscopic observations. These systems are now beginning to make extensive use of laser guide star (LGS) techniques to improve performance and provide increased sky coverage. Sodium LGS AO employs one or more lasers at 589-nm wavelength to produce an artificial guide star through excitation of sodium atoms in the mesosphere (90 km altitude). Because of its dependence on the abundance and distribution of sodium atoms in the mesosphere, this approach has its own unique set of difficulties not seen with natural stars. The sodium layer exhibits time-dependent variations in density and altitude, and since it is at a finite range, the LGS images become elongated due to the thickness of the layer and the offset between the laser projection point and the subapertures of a Shack-Hartmann wavefront sensor (SHWFS). Elongation causes the LGS image to be spread out resulting in a decrease in the signal-to-noise ratio which, in turn, leads to an increase in SHWFS measurement error and therefore an increased error in wavefront phase reconstruction. To address the problem of elongation, and also to provide a higher level of readout performance and reduced readout noise, a new type of charge-coupled device (CCD) is now under development for Shack-Hartmann wavefront sensing called the polar coordinate CCD. In this device, discrete imaging arrays are provided in each SHWFS subaperture and the size, shape and orientation of each discrete imaging array are adjusted to optimally sample the LGS image. The device is referred to as the polar coordinate CCD because the location of each imager is defined by a polar coordinate system centred on the laser guide star projection point. This concept is especially suited to Extremely Large Telescopes (ELTs) where the effect of perspective elongation is a significant factor. In this paper, we evaluate the performance of centroiders based on this CCD geometry by evaluating the centroid error variance and also the linearity issues associated with LGS image sampling and truncation. We also describe how we will extend this work to address the problems presented by the time variability of the sodium layer and how this will impact SHWFS performance in LGS AO systems.

Shortwave infrared 512 x 2 line sensor for earth resources applications

NASA Astrophysics Data System (ADS)

Tower, J. R.; Pellon, L. E.; McCarthy, B. M.; Elabd, H.; Moldovan, A. G.; Kosonocky, W. F.; Kalshoven, J. E., Jr.; Tom, D.

1985-08-01

As part of the NASA remote-sensing Multispectral Linear Array Program, an edge-buttable 512 x 2 IRCCD line image sensor with 30-micron Pd2Si Schottky-barrier detectors is developed for operation with passive cooling at 120 K in the 1.1-2.5 micron short infrared band. On-chip CCD multiplexers provide one video output for each 512 detector band. The monolithic silicon line imager performance at a 4-ms optical integration time includes a signal-to-noise ratio of 241 for irradiance of 7.2 microwatts/sq cm at 1.65 microns wavelength, a 5000 dynamic range, a modulation transfer function, greater than 60 percent at the Nyquist frequency, and an 18-milliwatt imager chip total power dissipation. Blemish-free images with three percent nonuniformity under illumination and nonlinearity of 1.25 percent are obtained. A five SWIR imager hybrid focal plane was constructed, demonstrating the feasibility of arrays with only a two-detector loss at each joint.

Scanning Miniature Microscopes without Lenses

NASA Technical Reports Server (NTRS)

Wang, Yu

2009-01-01

The figure schematically depicts some alternative designs of proposed compact, lightweight optoelectronic microscopes that would contain no lenses and would generate magnified video images of specimens. Microscopes of this type were described previously in Miniature Microscope Without Lenses (NPO - 20218), NASA Tech Briefs, Vol. 22, No. 8 (August 1998), page 43 and Reflective Variants of Miniature Microscope Without Lenses (NPO 20610), NASA Tech Briefs, Vol. 26, No. 9 (September 1999), page 6a. To recapitulate: In the design and construction of a microscope of this type, the focusing optics of a conventional microscope are replaced by a combination of a microchannel filter and a charge-coupled-device (CCD) image detector. Elimination of focusing optics reduces the size and weight of the instrument and eliminates the need for the time-consuming focusing operation. The microscopes described in the cited prior articles contained two-dimensional CCDs registered with two-dimensional arrays of microchannels and, as such, were designed to produce full two-dimensional images, without need for scanning. The microscopes of the present proposal would contain one-dimensional (line image) CCDs registered with linear arrays of microchannels. In the operation of such a microscope, one would scan a specimen along a line perpendicular to the array axis (in other words, one would scan in pushbroom fashion). One could then synthesize a full two-dimensional image of the specimen from the line-image data acquired at one-pixel increments of position along the scan. In one of the proposed microscopes, a beam of unpolarized light for illuminating the specimen would enter from the side. This light would be reflected down onto the specimen by a nonpolarizing beam splitter attached to the microchannels at their lower ends. A portion of the light incident on the specimen would be reflected upward, through the beam splitter and along the microchannels, to form an image on the CCD. If the nonpolarizing beam splitter were replaced by a polarizing one, then the specimen would be illuminated by s-polarized light. Upon reflection from the specimen, some of the s-polarized light would become p-polarized. Only the p-polarized light would contribute to the image on the CCD; in other words, the image would contain information on the polarization rotating characteristic of the specimen.

An ultrahigh-speed color video camera operating at 1,000,000 fps with 288 frame memories

NASA Astrophysics Data System (ADS)

Kitamura, K.; Arai, T.; Yonai, J.; Hayashida, T.; Kurita, T.; Maruyama, H.; Namiki, J.; Yanagi, T.; Yoshida, T.; van Kuijk, H.; Bosiers, Jan T.; Saita, A.; Kanayama, S.; Hatade, K.; Kitagawa, S.; Etoh, T. Goji

2008-11-01

We developed an ultrahigh-speed color video camera that operates at 1,000,000 fps (frames per second) and had capacity to store 288 frame memories. In 2005, we developed an ultrahigh-speed, high-sensitivity portable color camera with a 300,000-pixel single CCD (ISIS-V4: In-situ Storage Image Sensor, Version 4). Its ultrahigh-speed shooting capability of 1,000,000 fps was made possible by directly connecting CCD storages, which record video images, to the photodiodes of individual pixels. The number of consecutive frames was 144. However, longer capture times were demanded when the camera was used during imaging experiments and for some television programs. To increase ultrahigh-speed capture times, we used a beam splitter and two ultrahigh-speed 300,000-pixel CCDs. The beam splitter was placed behind the pick up lens. One CCD was located at each of the two outputs of the beam splitter. The CCD driving unit was developed to separately drive two CCDs, and the recording period of the two CCDs was sequentially switched. This increased the recording capacity to 288 images, an increase of a factor of two over that of conventional ultrahigh-speed camera. A problem with the camera was that the incident light on each CCD was reduced by a factor of two by using the beam splitter. To improve the light sensitivity, we developed a microlens array for use with the ultrahigh-speed CCDs. We simulated the operation of the microlens array in order to optimize its shape and then fabricated it using stamping technology. Using this microlens increased the light sensitivity of the CCDs by an approximate factor of two. By using a beam splitter in conjunction with the microlens array, it was possible to make an ultrahigh-speed color video camera that has 288 frame memories but without decreasing the camera's light sensitivity.

Simultaneous Determination of Iron, Copper and Cobalt in Food Samples by CCD-diode Array Detection-Flow Injection Analysis with Partial Least Squares Calibration Model

NASA Astrophysics Data System (ADS)

Mi, Jiaping; Li, Yuanqian; Zhou, Xiaoli; Zheng, Bo; Zhou, Ying

2006-01-01

A flow injection-CCD diode array detection spectrophotometry with partial least squares (PLS) program for simultaneous determination of iron, copper and cobalt in food samples has been established. The method was based on the chromogenic reaction of the three metal ions and 2- (5-Bromo-2-pyridylazo)-5-diethylaminophenol, 5-Br-PADAP in acetic acid - sodium acetate buffer solution (pH5) with Triton X-100 and ascorbic acid. The overlapped spectra of the colored complexes were collected by charge-coupled device (CCD) - diode array detector and the multi-wavelength absorbance data was processed using partial least squares (PLS) algorithm. Optimum reaction conditions and parameters of flow injection analysis were investigated. The samples of tea, sesame, laver, millet, cornmeal, mung bean and soybean powder were determined by the proposed method. The average recoveries of spiked samples were 91.80%~100.9% for Iron, 92.50%~108.0% for Copper, 93.00%~110.5% for Cobalt, respectively with relative standard deviation (R.S.D) of 1.1%~12.1%. The sampling rate is 45 samples h-1. The determination results of the food samples were in good agreement between the proposed method and ICP-AES.

Method for Measurement of Multi-Degrees-of-Freedom Motion Parameters Based on Polydimethylsiloxane Cross-Coupling Diffraction Gratings.

PubMed

Duan, Junping; Zhu, Qiang; Qian, Kun; Guo, Hao; Zhang, Binzhen

2017-08-30

This work presents a multi-degrees-of-freedom motion parameter measurement method based on the use of cross-coupling diffraction gratings that were prepared on the two sides of a polydimethylsiloxane (PDMS) substrate using oxygen plasma processing technology. The laser beam that travels pass the cross-coupling optical grating would be diffracted into a two-dimensional spot array. The displacement and the gap size of the spot-array were functions of the movement of the laser source, as explained by the Fraunhofer diffraction effect. A 480 × 640 pixel charge-coupled device (CCD) was used to acquire images of the two-dimensional spot-array in real time. A proposed algorithm was then used to obtain the motion parameters. Using this method and the CCD described above, the resolutions of the displacement and the deflection angle were 0.18 μm and 0.0075 rad, respectively. Additionally, a CCD with a higher pixel count could improve the resolutions of the displacement and the deflection angle to sub-nanometer and micro-radian scales, respectively. Finally, the dynamic positions of hovering rotorcraft have been tracked and checked using the proposed method, which can be used to correct the craft's position and provide a method for aircraft stabilization in the sky.

Method for Measurement of Multi-Degrees-of-Freedom Motion Parameters Based on Polydimethylsiloxane Cross-Coupling Diffraction Gratings

NASA Astrophysics Data System (ADS)

Duan, Junping; Zhu, Qiang; Qian, Kun; Guo, Hao; Zhang, Binzhen

2017-08-01

This work presents a multi-degrees-of-freedom motion parameter measurement method based on the use of cross-coupling diffraction gratings that were prepared on the two sides of a polydimethylsiloxane (PDMS) substrate using oxygen plasma processing technology. The laser beam that travels pass the cross-coupling optical grating would be diffracted into a two-dimensional spot array. The displacement and the gap size of the spot-array were functions of the movement of the laser source, as explained by the Fraunhofer diffraction effect. A 480 × 640 pixel charge-coupled device (CCD) was used to acquire images of the two-dimensional spot-array in real time. A proposed algorithm was then used to obtain the motion parameters. Using this method and the CCD described above, the resolutions of the displacement and the deflection angle were 0.18 μm and 0.0075 rad, respectively. Additionally, a CCD with a higher pixel count could improve the resolutions of the displacement and the deflection angle to sub-nanometer and micro-radian scales, respectively. Finally, the dynamic positions of hovering rotorcraft have been tracked and checked using the proposed method, which can be used to correct the craft's position and provide a method for aircraft stabilization in the sky.

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.

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.

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.

Development and Characterization of a Chromotomosynthetic Hyperspectral Imaging System

DTIC Science & Technology

2013-03-01

being taken piece-by-piece with photons not collected simultaneously in all spatial or spectral regions, rejecting energy that could contribute to the...alone define the spatial sampling resolution of the system. Incident photons excite the photocathode, which causes a release of electrons that are...create the photons that are incident on the CCD. The fiberoptic coupling between the photocathode and CCD array introduces a FWHM blur with

Scientific grade CCDs from EG & G Reticon

NASA Technical Reports Server (NTRS)

Cizdziel, Philip J.

1990-01-01

The design and performance of three scientific grade CCDs are summarized: a 1200 x 400 astronomical array of 27 x 27 sq micron pixels, a 512 x 512 scientific array of 27 x 27 sq micron pixels and a 404 x 64 VNIR array of 52 x 52 sq micron pixels. Each of the arrays is fabricated using a four phase, double poly, buried n-channel, multi-pinned phase CCD process. Performance data for each sensor is presented.

Integrated infrared detector arrays for low-background applications

NASA Technical Reports Server (NTRS)

Mccreight, C. R.; Goebel, J. H.

1982-01-01

Advanced infrared detector and detector array technology is being developed and characterized for future NASA space astronomy applications. Si:Bi charge-injection-device arrays have been obtained, and low-background sensitivities comparable to that of good discrete detectors have been measured. Intrinsic arrays are being assessed, and laboratory and telescope data have been collected on a monolithic InSb CCD array. For wavelengths longer than 30 microns, improved Ge:Ga detectors have been produced, and steps have been taken to prove the feasibility of an integrated extrinsic germanium array. Other integrated arrays and cryogenic components are also under investigation.

Considerations on Circuit Design and Data Acquisition of a Portable Surface Plasmon Resonance Biosensing System.

PubMed

Chang, Keke; Chen, Ruipeng; Wang, Shun; Li, Jianwei; Hu, Xinran; Liang, Hao; Cao, Baiqiong; Sun, Xiaohui; Ma, Liuzheng; Zhu, Juanhua; Jiang, Min; Hu, Jiandong

2015-08-19

The aim of this study was to develop a circuit for an inexpensive portable biosensing system based on surface plasmon resonance spectroscopy. This portable biosensing system designed for field use is characterized by a special structure which consists of a microfluidic cell incorporating a right angle prism functionalized with a biomolecular identification membrane, a laser line generator and a data acquisition circuit board. The data structure, data memory capacity and a line charge-coupled device (CCD) array with a driving circuit for collecting the photoelectric signals are intensively focused on and the high performance analog-to-digital (A/D) converter is comprehensively evaluated. The interface circuit and the photoelectric signal amplifier circuit are first studied to obtain the weak signals from the line CCD array in this experiment. Quantitative measurements for validating the sensitivity of the biosensing system were implemented using ethanol solutions of various concentrations indicated by volume fractions of 5%, 8%, 15%, 20%, 25%, and 30%, respectively, without a biomembrane immobilized on the surface of the SPR sensor. The experiments demonstrated that it is possible to detect a change in the refractive index of an ethanol solution with a sensitivity of 4.99838 × 10(5) ΔRU/RI in terms of the changes in delta response unit with refractive index using this SPR biosensing system, whereby the theoretical limit of detection of 3.3537 × 10(-5) refractive index unit (RIU) and a high linearity at the correlation coefficient of 0.98065. The results obtained from a series of tests confirmed the practicality of this cost-effective portable SPR biosensing system.

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.

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 their flat CCD counterparts, lightening the cameras and enabling faster scanning and 3D integration of objects moving within a planetary terrain environment. Preliminary experiments conducted at the Sarnoff Corporation indicate the feasibility of curved CCD imagers with acceptable electro-optic integrity. Currently, we are in the process of evaluating the electro-optic performance of a curved wafer scale CCD imager. Detailed ray trace modeling and experimental electro-optical data performance obtained from the curved imager will be presented at the conference.

LSI arrays for space stations

NASA Technical Reports Server (NTRS)

Gassaway, J. D.

1976-01-01

Two approaches have been taken to study CCD's and some of their fundamental limitations. First a numerical analysis approach has been developed to solve the coupled transport and Poisson's equation for a thorough analysis of charge transfer in a CCD structure. The approach is formulated by treating the minority carriers as a surface distribution at the Si-SiO2 interface and setting up coupled difference equations for the charge and the potential. The SOR method is proposed for solving the two dimensional Poisson's equation for the potential. Methods are suggested for handling the discontinuities to improve convergence. Second, CCD shift registers were fabricated with parameters which should allow complete charge transfer independent of the transfer electrode gap width. A test instrument was designed and constructed which can be used to test this, or any similar, three phase CCD shift register.

Applications of charge-coupled device transversal filters to communication

NASA Technical Reports Server (NTRS)

Buss, D. D.; Bailey, W. H.; Brodersen, R. W.; Hewes, C. R.; Tasch, A. F., Jr.

1975-01-01

The paper discusses the computational power of state-of-the-art charged-coupled device (CCD) transversal filters in communications applications. Some of the performance limitations of CCD transversal filters are discussed, with attention given to time delay and bandwidth, imperfect charge transfer efficiency, weighting coefficient error, noise, and linearity. The application of CCD transversal filters to matched filtering, spectral filtering, and Fourier analysis is examined. Techniques for making programmable transversal filters are briefly outlined.

The development of a cryogenic over-pressure pump

NASA Astrophysics Data System (ADS)

Alvarez, M.; Cease, H.; Flaugher, B.; Flores, R.; Garcia, J.; Lathrop, A.; Ruiz, F.

2014-01-01

A cryogenic over-pressure pump (OPP) was tested in the prototype telescope liquid nitrogen (LN2) cooling system for the Dark Energy Survey (DES) Project. This OPP consists of a process cylinder (PC), gas generator, and solenoid operated valves (SOVs). It is a positive displacement pump that provided intermittent liquid nitrogen (LN2) flow to an array of charge couple devices (CCDs) for the prototype Dark Energy Camera (DECam). In theory, a heater submerged in liquid would generate the drive gas in a closed loop cooling system. The drive gas would be injected into the PC to displace that liquid volume. However, due to limitations of the prototype closed loop nitrogen system (CCD cooling system) for DECam, a quasiclosed-loop nitrogen system was created. During the test of the OPP, the CCD array was cooled to its designed set point temperature of 173K. It was maintained at that temperature via electrical heaters. The performance of the OPP was captured in pressure, temperature, and flow rate in the CCD LN2 cooling system at Fermi National Accelerator Laboratory (FNAL).

Methods of dark signal determination for CCD array spectroradiometers used in solar UVR measurements.

PubMed

Baczynska, K A; Khazova, M

2015-02-01

The methods of the dark signal determination by direct contemporaneous measurements using a light spectrum and modelling of the dark signal based on the dark signal characterisation data were discussed. These techniques were tested with two charge-couple detectors (CCD) array spectroradiometers used in solar UVR measurements. The sensitivity of both instruments was significantly reduced when shutters were used; the measured signal varied by up to 12% depending on the orientation of the shutter. The shutters should be permanently attached to the SSR, so that the orientation cannot be changed to prevent an increase in uncertainty. The method of using blind pixels from the optically inactive part of the CCD array in a light spectrum could be used to derive the dark signal with some limitations for integration times <10 s for the QE65000. An alternative method of deriving the dark signal from light measurements using out-of-range pixels has been proved impossible due to out-of-range stray light in both instruments. The dark signal was characterised for the range of integration times and ambient temperatures of 15-35°C. Based on these data, the model of the dark signal was developed so that a single value of the dark signal can be subtracted over the whole spectral range if the instrument temperature is known. © Crown copyright 2014.

Composite x-ray image assembly for large-field digital mammography with one- and two-dimensional positioning of a focal plane array

NASA Technical Reports Server (NTRS)

Halama, G.; McAdoo, J.; Liu, H.

1998-01-01

To demonstrate the feasibility of a novel large-field digital mammography technique, a 1024 x 1024 pixel Loral charge-coupled device (CCD) focal plane array (FPA) was positioned in a mammographic field with one- and two-dimensional scan sequences to obtain 950 x 1800 pixel and 3600 x 3600 pixel composite images, respectively. These experiments verify that precise positioning of FPAs produced seamless composites and that the CCD mosaic concept has potential for high-resolution, large-field imaging. The proposed CCD mosaic concept resembles a checkerboard pattern with spacing left between the CCDs for the driver and readout electronics. To obtain a complete x-ray image, the mosaic must be repositioned four times, with an x-ray exposure at each position. To reduce the patient dose, a lead shield with appropriately patterned holes is placed between the x-ray source and the patient. The high-precision motorized translation stages and the fiber-coupled-scintillating-screen-CCD sensor assembly were placed in the position usually occupied by the film cassette. Because of the high mechanical precision, seamless composites were constructed from the subimages. This paper discusses the positioning, image alignment procedure, and composite image results. The paper only addresses the formation of a seamless composite image from subimages and will not consider the effects of the lead shield, multiple CCDs, or the speed of motion.

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.

Time and space integrating acousto-optic folded spectrum processing for SETI

NASA Technical Reports Server (NTRS)

Wagner, K.; Psaltis, D.

1986-01-01

Time and space integrating folded spectrum techniques utilizing acousto-optic devices (AOD) as 1-D input transducers are investigated for a potential application as wideband, high resolution, large processing gain spectrum analyzers in the search for extra-terrestrial intelligence (SETI) program. The space integrating Fourier transform performed by a lens channels the coarse spectral components diffracted from an AOD onto an array of time integrating narrowband fine resolution spectrum analyzers. The pulsing action of a laser diode samples the interferometrically detected output, aliasing the fine resolution components to baseband, as required for the subsequent charge coupled devices (CCD) processing. The raster scan mechanism incorporated into the readout of the CCD detector array is used to unfold the 2-D transform, reproducing the desired high resolution Fourier transform of the input signal.

Modulation transfer function of partial gating detector by liquid crystal auto-controlling light intensity

NASA Astrophysics Data System (ADS)

Yang, Xusan; Tang, Yuanhe; Liu, Kai; Liu, Hanchen; Gao, Haiyang; Li, Qing; Zhang, Ruixia; Ye, Na; Liang, Yuan; Zhao, Gaoxiang

2008-12-01

Based on the electro-optical properties of liquid crystal, we have designed a novel partial gating detector. Liquid crystal can be taken to change its own transmission according to the light intensity outside. Every single pixel of the image is real-time modulated by liquid crystal, thus the strong light is weakened and low light goes through the detector normally .The purpose of partial-gating strong light (>105lx) can be achieved by this detector. The modulation transfer function (MTF) equations of the main optical sub-systems are calculated in this paper, they are liquid crystal panels, linear fiber panel and CCD array detector. According to the relevant size, the MTF value of this system is fitted out. The result is MTF= 0.518 at Nyquist frequency.

Internal reflection sensors with high angular resolution

NASA Astrophysics Data System (ADS)

Shavirin, I.; Strelkov, O.; Vetskous, A.; Norton-Wayne, L.; Harwood, R.

1996-07-01

We discuss the use of total internal reflection for the production of sensors with high angular resolution. These sensors are intended for measurement of the angle between a sensor's axis and the direction to a source of radiation or reflecting object. Sensors of this type are used in controlling the position of machine parts in robotics and industry, orienting space vehicles and astronomic devices in relation to the Sun, and as autocollimators for checking angles of deviation. This kind of sensor was used in the Apollo space vehicle some 20 years ago. Using photodetectors with linear and area CCD arrays has opened up new application possibilities for appropriately designed sensors. A generalized methodology is presented applicable to a wide range of tasks. Some modifications that can improve the performance of the basic design are described.

Degradation of optical components in space

NASA Technical Reports Server (NTRS)

Blue, M. D.

1993-01-01

This report concerns two types of optical components: multilayer filters and mirrors, and self-scanned imaging arrays using charge coupled device (CCD) readouts. For the filters and mirrors, contamination produces a strong reduction in transmittance in the ultraviolet spectral region, but has little or no effect in the visible and infrared spectral regions. Soft substrates containing halides are unsatisfactory as windows or substrates. Materials choice for dielectric layers should also reflect such considerations. Best performance is also found for the harder materials. Compaction of the layers and interlayer diffusion causes a blue shift in center wavelength and loss of throughput. For sensors using CCD's, shifts in gate voltage and reductions in transfer efficiency occur. Such effects in CCD's are in accord with expectations of the effects of the radiation dose on the device. Except for optical fiber, degradation of CCD's represents the only ionizing-radiation induced effect on the Long Duration Exposure Facility (LDEF) optical systems components that has been observed.

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.

Detecting Near-Earth Objects Using Cross-Correlation with a Point Spread Function

DTIC Science & Technology

2009-03-01

greater than .001 seconds [Goodman, 2000]. Cross-Correlation Cross-Correlation measures the strength and direction of the linear relationship between...real(ifft2(fftshift(otf_long)))); %normalize point spread funtion 55 if (Corner == 1) psf_source = makeshift(psf*source_img(ccd_x/2,ccd_y/2

Method of orthogonally splitting imaging pose measurement

NASA Astrophysics Data System (ADS)

Zhao, Na; Sun, Changku; Wang, Peng; Yang, Qian; Liu, Xintong

2018-01-01

In order to meet the aviation's and machinery manufacturing's pose measurement need of high precision, fast speed and wide measurement range, and to resolve the contradiction between measurement range and resolution of vision sensor, this paper proposes an orthogonally splitting imaging pose measurement method. This paper designs and realizes an orthogonally splitting imaging vision sensor and establishes a pose measurement system. The vision sensor consists of one imaging lens, a beam splitter prism, cylindrical lenses and dual linear CCD. Dual linear CCD respectively acquire one dimensional image coordinate data of the target point, and two data can restore the two dimensional image coordinates of the target point. According to the characteristics of imaging system, this paper establishes the nonlinear distortion model to correct distortion. Based on cross ratio invariability, polynomial equation is established and solved by the least square fitting method. After completing distortion correction, this paper establishes the measurement mathematical model of vision sensor, and determines intrinsic parameters to calibrate. An array of feature points for calibration is built by placing a planar target in any different positions for a few times. An terative optimization method is presented to solve the parameters of model. The experimental results show that the field angle is 52 °, the focus distance is 27.40 mm, image resolution is 5185×5117 pixels, displacement measurement error is less than 0.1mm, and rotation angle measurement error is less than 0.15°. The method of orthogonally splitting imaging pose measurement can satisfy the pose measurement requirement of high precision, fast speed and wide measurement range.

Feasibility Study for a Dual Field of View-Single Detector Array Infrared System.

DTIC Science & Technology

1974-06-01

for 525 TV. Per Channelt C. DC. Ainlog& Dgitl Tretrs b~ td ~Secial multipleaed. Organ- 500 li1 cani be organized CAC nlg Dgia eprtr.Untdt 80 lioal...coupled transport phenomenon: charge coupled device (CCD) and bucket brigade device U ( BBD ). These devices are basically dynamic shift registers that...can be connected to form the serial in-serial uut memory. Both the CCD and BBD function by wanipulating char-e along a series of electrodes without

Characterization and Design of Digital Pointing Subsystem for Optical Communication Demonstrator

NASA Technical Reports Server (NTRS)

Racho, C.; Portillo, A.

1998-01-01

The Optical Communications Demonstrator (OCD) is a laboratory-based lasercom demonstration terminal designed to validate several key technologies, including beacon acquisition, high bandwidth tracking, precision bearn pointing, and point-ahead compensation functions. It has been under active development over the past few years. The instrument uses a CCD array detector for both spatial acquisition and high-bandwidth tracking, and a fiber coupled laser transmitter. The array detector tracking concept provides wide field-of-view acquisition and permits effective platform jitter compensation and point-ahead control using only one steering mirror. This paper describes the detailed design and characterization of the digital control loop system which includes the Fast Steering Mirror (FSM), the CCD image tracker, and the associated electronics. The objective is to improve the overall system performance using laboratory measured data. The. design of the digital control loop is based on a linear time invariant open loop model. The closed loop performance is predicted using the theoretical model. With the digital filter programmed into the OCD control software, data is collected to verify the predictions. This paper presents the results of the, system modeling and performance analysis. It has been shown that measurement data closely matches theoretical predictions. An important part of the laser communication experiment is the ability of FSM to track the laser beacon within the. required tolerances. The pointing must be maintained to an accuracy that is much smaller than the transmit signal beamwidth. For an earth orbit distance, the system must be able to track the receiving station to within a few microradians. The failure. to do so will result in a severely degraded system performance.

High precision computing with charge domain devices and a pseudo-spectral method therefor

NASA Technical Reports Server (NTRS)

Barhen, Jacob (Inventor); Toomarian, Nikzad (Inventor); Fijany, Amir (Inventor); Zak, Michail (Inventor)

1997-01-01

The present invention enhances the bit resolution of a CCD/CID MVM processor by storing each bit of each matrix element as a separate CCD charge packet. The bits of each input vector are separately multiplied by each bit of each matrix element in massive parallelism and the resulting products are combined appropriately to synthesize the correct product. In another aspect of the invention, such arrays are employed in a pseudo-spectral method of the invention, in which partial differential equations are solved by expressing each derivative analytically as matrices, and the state function is updated at each computation cycle by multiplying it by the matrices. The matrices are treated as synaptic arrays of a neural network and the state function vector elements are treated as neurons. In a further aspect of the invention, moving target detection is performed by driving the soliton equation with a vector of detector outputs. The neural architecture consists of two synaptic arrays corresponding to the two differential terms of the soliton-equation and an adder connected to the output thereof and to the output of the detector array to drive the soliton equation.

Real-time two-dimensional imaging of potassium ion distribution using an ion semiconductor sensor with charged coupled device technology.

PubMed

Hattori, Toshiaki; Masaki, Yoshitomo; Atsumi, Kazuya; Kato, Ryo; Sawada, Kazuaki

2010-01-01

Two-dimensional real-time observation of potassium ion distributions was achieved using an ion imaging device based on charge-coupled device (CCD) and metal-oxide semiconductor technologies, and an ion selective membrane. The CCD potassium ion image sensor was equipped with an array of 32 × 32 pixels (1024 pixels). It could record five frames per second with an area of 4.16 × 4.16 mm(2). Potassium ion images were produced instantly. The leaching of potassium ion from a 3.3 M KCl Ag/AgCl reference electrode was dynamically monitored in aqueous solution. The potassium ion selective membrane on the semiconductor consisted of plasticized poly(vinyl chloride) (PVC) with bis(benzo-15-crown-5). The addition of a polyhedral oligomeric silsesquioxane to the plasticized PVC membrane greatly improved adhesion of the membrane onto Si(3)N(4) of the semiconductor surface, and the potential response was stabilized. The potential response was linear from 10(-2) to 10(-5) M logarithmic concentration of potassium ion. The selectivity coefficients were K(K(+),Li(+))(pot) = 10(-2.85), K(K(+),Na(+))(pot) = 10(-2.30), K(K(+),Rb(+))(pot) =10(-1.16), and K(K(+),Cs(+))(pot) = 10(-2.05).

X-Ray Diffraction Apparatus

NASA Technical Reports Server (NTRS)

Blake, David F. (Inventor); Bryson, Charles (Inventor); Freund, Friedmann (Inventor)

1996-01-01

An x-ray diffraction apparatus for use in analyzing the x-ray diffraction pattern of a sample is introduced. The apparatus includes a beam source for generating a collimated x-ray beam having one or more discrete x-ray energies, a holder for holding the sample to be analyzed in the path of the beam, and a charge-coupled device having an array of pixels for detecting, in one or more selected photon energy ranges, x-ray diffraction photons produced by irradiating such a sample with said beam. The CCD is coupled to an output unit which receives input information relating to the energies of photons striking each pixel in the CCD, and constructs the diffraction pattern of photons within a selected energy range striking the CCD.

Automatic detection of recoil-proton tracks and background rejection criteria in liquid scintillator-micro-capillary-array fast neutron spectrometer

NASA Astrophysics Data System (ADS)

Mor, Ilan; Vartsky, David; Dangendorf, Volker; Tittelmeier, Kai.; Weierganz, Mathias; Goldberg, Mark Benjamin; Bar, Doron; Brandis, Michal

2018-06-01

We describe an analysis procedure for automatic unambiguous detection of fast-neutron-induced recoil proton tracks in a micro-capillary array filled with organic liquid scintillator. The detector is viewed by an intensified CCD camera. This imaging neutron detector possesses the capability to perform high position-resolution (few tens of μm), energy-dispersive transmission-imaging using ns-pulsed beams. However, when operated with CW or DC beams, it also features medium-quality spectroscopic capabilities for incident neutrons in the energy range 2-20 MeV. In addition to the recoil proton events which display a continuous extended track structure, the raw images exhibit complex ion-tracks from nuclear interactions of fast-neutrons in the scintillator, capillaries quartz-matrix and CCD. Moreover, as expected, one also observes a multitude of isolated scintillation spots of varying intensity (henceforth denoted "blobs") that originate from several different sources, such as: fragmented proton tracks, gamma-rays, heavy-ion reactions as well as events and noise that occur in the image-intensifier and CCD. In order to identify the continuous-track recoil proton events and distinguish them from all these background events, a rapid, computerized and automatic track-recognition-procedure was developed. Based on an appropriately weighted analysis of track parameters such as: length, width, area and overall light intensity, the method is capable of distinguishing a single continuous-track recoil proton from typically surrounding several thousands of background events that are found in each CCD frame.

Quadratic correlation filters for optical correlators

NASA Astrophysics Data System (ADS)

Mahalanobis, Abhijit; Muise, Robert R.; Vijaya Kumar, Bhagavatula V. K.

2003-08-01

Linear correlation filters have been implemented in optical correlators and successfully used for a variety of applications. The output of an optical correlator is usually sensed using a square law device (such as a CCD array) which forces the output to be the squared magnitude of the desired correlation. It is however not a traditional practice to factor the effect of the square-law detector in the design of the linear correlation filters. In fact, the input-output relationship of an optical correlator is more accurately modeled as a quadratic operation than a linear operation. Quadratic correlation filters (QCFs) operate directly on the image data without the need for feature extraction or segmentation. In this sense, the QCFs retain the main advantages of conventional linear correlation filters while offering significant improvements in other respects. Not only is more processing required to detect peaks in the outputs of multiple linear filters, but choosing a winner among them is an error prone task. In contrast, all channels in a QCF work together to optimize the same performance metric and produce a combined output that leads to considerable simplification of the post-processing. In this paper, we propose a novel approach to the design of quadratic correlation based on the Fukunaga Koontz transform. Although quadratic filters are known to be optimum when the data is Gaussian, it is expected that they will perform as well as or better than linear filters in general. Preliminary performance results are provided that show that quadratic correlation filters perform better than their linear counterparts.

Digital Mammography with a Mosaic of CCD Arrays

NASA Technical Reports Server (NTRS)

Jalink, Antony, Jr. (Inventor); McAdoo, James A. (Inventor)

1998-01-01

A digital mammography device uses a mosaic of electronic digital imaging arrays to scan an x-ray image is discussed. The mosaic of arrays is repositioned several times to expose different portions of the image, until the entire image is scanned. The data generated by the arrays during each exposure is stored in a computer. After the final exposure, the computer combines data of the several partial images to produce a composite of the original x-ray image. An aperture plate is used to reduce scatter and the overall exposure of the patient to x-rays.

Advanced optical position sensors for magnetically suspended wind tunnel models

NASA Technical Reports Server (NTRS)

Lafleur, S.

1985-01-01

A major concern to aerodynamicists has been the corruption of wind tunnel test data by model support structures, such as stings or struts. A technique for magnetically suspending wind tunnel models was considered by Tournier and Laurenceau (1957) in order to overcome this problem. This technique is now implemented with the aid of a Large Magnetic Suspension and Balance System (LMSBS) and advanced position sensors for measuring model attitude and position within the test section. Two different optical position sensors are discussed, taking into account a device based on the use of linear CCD arrays, and a device utilizing area CID cameras. Current techniques in image processing have been employed to develop target tracking algorithms capable of subpixel resolution for the sensors. The algorithms are discussed in detail, and some preliminary test results are reported.

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.

VizieR Online Data Catalog: Observation of six NSVS eclipsing binaries (Dimitrov+, 2015)

NASA Astrophysics Data System (ADS)

Dimitrov, D. P.; Kjurkchieva, D. P.

2017-11-01

We managed to separate a sample of about 40 ultrashort-period candidates from the Northern Sky Variability Survey (NSVS, Wozniak et al. 2004AJ....127.2436W) appropriate for follow-up observations at Rozhen observatory (δ>-10°). Follow-up CCD photometry of the targets in the VRI bands was carried out with the three telescopes of the Rozhen National Astronomical Observatory. The 2-m RCC telescope is equipped with a VersArray CCD camera (1340x1300 pixels, 20 μm/pixel, field of 5.35x5.25 arcmin2). The 60-cm Cassegrain telescope is equipped with a FLI PL09000 CCD camera (3056x3056 pixels, 12 μm/pixel, field of 17.1x17.1 arcmin2). The 50/70 cm Schmidt telescope has a field of view (FoV) of around 1° and is equipped with a FLI PL 16803 CCD camera, 4096x4096 pixels, 9 μm/pixel size. (4 data files).

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.

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.

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.

Periodicity analysis on cat-eye reflected beam profiles of optical detectors

NASA Astrophysics Data System (ADS)

Gong, Mali; He, Sifeng

2017-05-01

The cat-eye effect reflected beam profiles of most optical detectors have a certain characteristic of periodicity, which is caused by array arrangement of sensors at their optical focal planes. It is the first time to find and prove that the reflected beam profile becomes several periodic spots at the reflected propagation distance corresponding to half the imaging distance of a CCD camera. Furthermore, the spatial cycle of these spots is approximately constant, independent of the CCD camera's imaging distance, which is related only to the focal length and pixel size of the CCD sensor. Thus, we can obtain the imaging distance and intrinsic parameters of the optical detector by analyzing its cat-eye reflected beam profiles. This conclusion can be applied in the field of non-cooperative cat-eye target recognition.

Scintillation imaging of tritium radioactivity distribution during tritiated thymidine uptake by PC12 cells using a melt-on scintillator.

PubMed

Irikura, Namiko; Miyoshi, Hirokazu; Shinohara, Yasuo

2017-02-01

A scintillation image of tritium fixed in a melt-on scintillator was obtained using a charged-coupled device (CCD) imager, and a linear relationship was observed between the intensity of the scintillation image and the radioactivity of tritium. In a [ 3 H]thymidine uptake experiment, a linear correlation between the intensity of the CCD image and the dilution ratio of cells was confirmed. Scintillation imaging has the potential for use in direct observation of tritium radioactivity distribution. Copyright © 2016 Elsevier Ltd. All rights reserved.

Model-based frequency response characterization of a digital-image analysis system for epifluorescence microscopy

NASA Technical Reports Server (NTRS)

Hazra, Rajeeb; Viles, Charles L.; Park, Stephen K.; Reichenbach, Stephen E.; Sieracki, Michael E.

1992-01-01

Consideration is given to a model-based method for estimating the spatial frequency response of a digital-imaging system (e.g., a CCD camera) that is modeled as a linear, shift-invariant image acquisition subsystem that is cascaded with a linear, shift-variant sampling subsystem. The method characterizes the 2D frequency response of the image acquisition subsystem to beyond the Nyquist frequency by accounting explicitly for insufficient sampling and the sample-scene phase. Results for simulated systems and a real CCD-based epifluorescence microscopy system are presented to demonstrate the accuracy of the method.

Simultaneous measurement of monocomponent droplet temperature/refractive index, size and evaporation rate with phase rainbow refractometry

NASA Astrophysics Data System (ADS)

Wu, Yingchun; Crua, Cyril; Li, Haipeng; Saengkaew, Sawitree; Mädler, Lutz; Wu, Xuecheng; Gréhan, Gérard

2018-07-01

The accurate measurements of droplet temperature, size and evaporation rate are of great importance to characterize the heat and mass transfer during evaporation/condensation processes. The nanoscale size change of a micron-sized droplet exactly describes its transient mass transfer, but is difficult to measure because it is smaller than the resolutions of current size measurement techniques. The Phase Rainbow Refractometry (PRR) technique is developed and applied to measure droplet temperature, size and transient size changes and thereafter evaporation rate simultaneously. The measurement principle of PRR is theoretically derived, and it reveals that the phase shift of the time-resolved ripple structures linearly depends on, and can directly yield, nano-scale size changes of droplets. The PRR technique is first verified through the simulation of rainbows of droplets with changing size, and results show that PRR can precisely measure droplet refractive index, absolute size, as well as size change with absolute and relative errors within several nanometers and 0.6%, respectively, and thus PRR permits accurate measurements of transient droplet evaporation rates. The evaporations of flowing single n-nonane droplet and mono-dispersed n-heptane droplet stream are investigated by two PRR systems with a high speed linear CCD and a low speed array CCD, respectively. Their transient evaporation rates are experimentally determined and quantitatively agree well with the theoretical values predicted by classical Maxwell and Stefan-Fuchs models. With the demonstration of evaporation rate measurement of monocomponent droplet in this work, PRR is an ideal tool for measurements of transient droplet evaporation/condensation processes, and can be extended to multicomponent droplets in a wide range of industrially-relevant applications.

New light-amplifier-based detector designs for high spatial resolution and high sensitivity CBCT mammography and fluoroscopy

PubMed Central

Rudin, Stephen; Kuhls, Andrew T.; Yadava, Girijesh K.; Josan, Gaurav C.; Wu, Ye; Chityala, Ravishankar N.; Rangwala, Hussain S.; Ciprian Ionita, N.; Hoffmann, Kenneth R.; Bednarek, Daniel R.

2011-01-01

New cone-beam computed tomographic (CBCT) mammography system designs are presented where the detectors provide high spatial resolution, high sensitivity, low noise, wide dynamic range, negligible lag and high frame rates similar to features required for high performance fluoroscopy detectors. The x-ray detectors consist of a phosphor coupled by a fiber-optic taper to either a high gain image light amplifier (LA) then CCD camera or to an electron multiplying CCD. When a square-array of such detectors is used, a field-of-view (FOV) to 20 × 20 cm can be obtained where the images have pixel-resolution of 100 µm or better. To achieve practical CBCT mammography scan-times, 30 fps may be acquired with quantum limited (noise free) performance below 0.2 µR detector exposure per frame. Because of the flexible voltage controlled gain of the LA’s and EMCCDs, large detector dynamic range is also achievable. Features of such detector systems with arrays of either generation 2 (Gen 2) or 3 (Gen 3) LAs optically coupled to CCD cameras or arrays of EMCCDs coupled directly are compared. Quantum accounting analysis is done for a variety of such designs where either the lowest number of information carriers off the LA photo-cathode or electrons released in the EMCCDs per x-ray absorbed in the phosphor are large enough to imply no quantum sink for the design. These new LA- or EMCCD-based systems could lead to vastly improved CBCT mammography, ROI-CT, or fluoroscopy performance compared to systems using flat panels. PMID:21297904

New light-amplifier-based detector designs for high spatial resolution and high sensitivity CBCT mammography and fluoroscopy

NASA Astrophysics Data System (ADS)

Rudin, Stephen; Kuhls, Andrew T.; Yadava, Girijesh K.; Josan, Gaurav C.; Wu, Ye; Chityala, Ravishankar N.; Rangwala, Hussain S.; Ionita, N. Ciprian; Hoffmann, Kenneth R.; Bednarek, Daniel R.

2006-03-01

New cone-beam computed tomographic (CBCT) mammography system designs are presented where the detectors provide high spatial resolution, high sensitivity, low noise, wide dynamic range, negligible lag and high frame rates similar to features required for high performance fluoroscopy detectors. The x-ray detectors consist of a phosphor coupled by a fiber-optic taper to either a high gain image light amplifier (LA) then CCD camera or to an electron multiplying CCD. When a square-array of such detectors is used, a field-of-view (FOV) to 20 x 20 cm can be obtained where the images have pixel-resolution of 100 μm or better. To achieve practical CBCT mammography scan-times, 30 fps may be acquired with quantum limited (noise free) performance below 0.2 μR detector exposure per frame. Because of the flexible voltage controlled gain of the LA's and EMCCDs, large detector dynamic range is also achievable. Features of such detector systems with arrays of either generation 2 (Gen 2) or 3 (Gen 3) LAs optically coupled to CCD cameras or arrays of EMCCDs coupled directly are compared. Quantum accounting analysis is done for a variety of such designs where either the lowest number of information carriers off the LA photo-cathode or electrons released in the EMCCDs per x-ray absorbed in the phosphor are large enough to imply no quantum sink for the design. These new LA- or EMCCD-based systems could lead to vastly improved CBCT mammography, ROI-CT, or fluoroscopy performance compared to systems using flat panels.

Fixed mount wavefront sensor

DOEpatents

Neal, Daniel R.

2000-01-01

A rigid mount and method of mounting for a wavefront sensor. A wavefront dissector, such as a lenslet array, is rigidly mounted at a fixed distance relative to an imager, such as a CCD camera, without need for a relay imaging lens therebetween.

High-speed line-scan camera with digital time delay integration

NASA Astrophysics Data System (ADS)

Bodenstorfer, Ernst; Fürtler, Johannes; Brodersen, Jörg; Mayer, Konrad J.; Eckel, Christian; Gravogl, Klaus; Nachtnebel, Herbert

2007-02-01

Dealing with high-speed image acquisition and processing systems, the speed of operation is often limited by the amount of available light, due to short exposure times. Therefore, high-speed applications often use line-scan cameras, based on charge-coupled device (CCD) sensors with time delayed integration (TDI). Synchronous shift and accumulation of photoelectric charges on the CCD chip - according to the objects' movement - result in a longer effective exposure time without introducing additional motion blur. This paper presents a high-speed color line-scan camera based on a commercial complementary metal oxide semiconductor (CMOS) area image sensor with a Bayer filter matrix and a field programmable gate array (FPGA). The camera implements a digital equivalent to the TDI effect exploited with CCD cameras. The proposed design benefits from the high frame rates of CMOS sensors and from the possibility of arbitrarily addressing the rows of the sensor's pixel array. For the digital TDI just a small number of rows are read out from the area sensor which are then shifted and accumulated according to the movement of the inspected objects. This paper gives a detailed description of the digital TDI algorithm implemented on the FPGA. Relevant aspects for the practical application are discussed and key features of the camera are listed.

A merged pipe organ binary-analog correlator

NASA Astrophysics Data System (ADS)

Miller, R. S.; Berry, M. B.

1982-02-01

The design of a 96-stage, programmable binary-analog correlator is described. An array of charge coupled device (CCD) delay lines of differing lengths perform the delay and sum functions. Merging of several CCD channels is employed to reduce the active area. This device architecture allows simplified output detection while maintaining good device performance at higher speeds (5-10 MHz). Experimental results indicate a 50 dB broadband dynamic range and excellent agreement with the theoretical processing gain (19.8 dB) when operated at a 6 MHz sampling frequency as a p-n sequence matched filter.

Spectral transmissometer and radiometer - Design and initial results. [of free drifting experiment in Pacific Ocean

NASA Technical Reports Server (NTRS)

Carder, Kendall L.; Steward, Robert G.; Peacock, Thomas G.; Payne, Paul R.; Peck, Wayne

1988-01-01

A new solid-state spectral transmissometer and radiometer is described. The radiometer measures upwelling radiance, downwelling irradiance, and beam transmittance from 390 to 750 nm with channel widths of 2.35 nm. The spectrometer consists of a 256 element CCD linear array collecting light dispersed by a reflection grating in a modified Littrow configuration. The spectrometer is time and space-shared among the three signal types. The instrument has been deployed as a free-drifting buoy and in the profiling mode, with data stored internally on a magnetic bubble memory or sent up a conducting cable as desired. Power can be supplied either by a detachable external battery pack or through conducting cable. The instrument has been deployed in the oligotrophic North Pacific Central Gyre and in the eutrophic Straits of Juan de Fuca, and preliminary results for each region are discussed.

Reflectometer for pseudo-Brewster angle spectrometry (BAIRS)

NASA Astrophysics Data System (ADS)

Potter, Roy F.

2000-10-01

A simple, robust reflectometer, pre-set for several angles of incidence (AOI), has been designed and used for determining the optical parameters of opaque samples having a specular surface. A single, linear polarizing element permits the measurement of perpendicular(s) and parallel (p) reflectence at each AOI. The BAIRS algorithm determines the empirical optical parameters for the subject surface at the pseudo-Brewster AOI, based on the measurement of p/s at two AOI's and, in turn the optical constants n and k (or (epsilon) 1 and (epsilon) 2). Radiation sources in current use, are a stabilized tungsten-halide lamp or a deuterium lamp for the visible and near UV spectral regions. Silica fiber optics and lenses deliver input and output radiation from the source and to a CCD array scanned diffraction spectrometer. Results for a sample of GaAs will be presented along with a discussion of dispersion features in the optical constant spectra.

Development of InSb charge-coupled infrared imaging devices: Linear imager

NASA Technical Reports Server (NTRS)

Phillips, J. D.

1976-01-01

The following results were accomplished in the development of charge coupled infrared imaging devices: (1) a four-phase overlapping gate with 9 transfers (2-bits) and 1.0-mil gate lengths was successfully operated, (2) the measured transfer efficiency of 0.975 for this device is in excellent agreement with predictions for the reduced gate length device, (3) mask revisions of the channel stop metal on the 8582 mask have been carried out with the result being a large increase in the dc yield of the tested devices, (4) partial optical sensitivity to chopped blackbody radiation was observed for an 8582 9-bit imager, (5) analytical consideration of the modulation transfer function degradation caused by transfer inefficiency in the CCD registers was presented, and (6) for larger array lengths or for the insertion of isolated bits between sensors, improvements in InSb fabrication technology with corresponding decrease in the interface state density are required.

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 setup. This paper describes certain novel techniques of design and implementation of system calibration for effective Imaging to produce better quality data product especially while handling high resolution data.

A curved surface micro-moiré method and its application in evaluating curved surface residual stress

NASA Astrophysics Data System (ADS)

Zhang, Hongye; Wu, Chenlong; Liu, Zhanwei; Xie, Huimin

2014-09-01

The moiré method is typically applied to the measurement of deformations of a flat surface while, for a curved surface, this method is rarely used other than for projection moiré or moiré interferometry. Here, a novel colour charge-coupled device (CCD) micro-moiré method has been developed, based on which a curved surface micro-moiré (CSMM) method is proposed with a colour CCD and optical microscope (OM). In the CSMM method, no additional reference grating is needed as a Bayer colour filter array (CFA) installed on the OM in front of the colour CCD image sensor performs this role. Micro-moiré fringes with high contrast are directly observed with the OM through the Bayer CFA under the special condition of observing a curved specimen grating. The principle of the CSMM method based on a colour CCD micro-moiré method and its application range and error analysis are all described in detail. In an experiment, the curved surface residual stress near a welded seam on a stainless steel tube was investigated using the CSMM method.

VizieR Online Data Catalog: Photometry of multiple stars at NAOR&ASV in 2015 (Cvetkovic+, 2017)

NASA Astrophysics Data System (ADS)

Cvetkovic, Z.; Pavlovic, R.; Boeva, S.

2018-05-01

This is the ninth series of CCD observations of double and multiple stars, obtained at the Bulgarian National Astronomical Observatory at Rozhen (NAOR) over five nights. As previously, the CCD camera VersArray 1300B was used, which was attached to the 2 m telescope. For each double or multiple star, five CCD frames in the Johnson B filter and five frames in the Johnson V filter were taken, which enabled us to determine the magnitude difference for these filters. In 2015 at the Astronomical Station at Vidojevica (ASV), over a total of 23 nights, observations were carried out by using the 60 cm telescope with a Cassegrain optical system. This is the fourth observational series at ASV since the work started there in 2011. In the observations we used the Apogee Alta U42 CCD camera whose characteristics can be found in the paper by Cvetkovic et al. (2016, J/AJ/151/58). Every pair was observed five times in the Cousins/Bessel B filter and five times in the Cousins/Bessel V one. (3 data files).

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.

IDSAC-IUCAA digital sampler array controller

NASA Astrophysics Data System (ADS)

Chattopadhyay, Sabyasachi; Chordia, Pravin; Ramaprakash, A. N.; Burse, Mahesh P.; Joshi, Bhushan; Chillal, Kalpesh

2016-07-01

In order to run the large format detector arrays and mosaics that are required by most astronomical instruments, readout electronic controllers are required which can process multiple CCD outputs simultaneously at high speeds and low noise levels. These CCD controllers need to be modular and configurable, should be able to run multiple detector types to cater to a wide variety of requirements. IUCAA Digital Sampler Array Controller (IDSAC), is a generic CCD Controller based on a fully scalable architecture which is adequately flexible and powerful enough to control a wide variety of detectors used in ground based astronomy. The controller has a modular backplane architecture that consists of Single Board Controller Cards (SBCs) and can control up to 5 CCDs (mosaic or independent). Each Single Board Controller (SBC) has all the resources to a run Single large format CCD having up to four outputs. All SBCs are identical and are easily interchangeable without needing any reconfiguration. A four channel video processor on each SBC can process up to four output CCDs with or without dummy outputs at 0.5 Megapixels/Sec/Channel with 16 bit resolution. Each SBC has a USB 2.0 interface which can be connected to a host computer via optional USB to Fibre converters. The SBC uses a reconfigurable hardware (FPGA) as a Master Controller. IDSAC offers Digital Correlated Double Sampling (DCDS) to eliminate thermal kTC noise. CDS performed in Digital domain (DCDS) has several advantages over its analog counterpart, such as - less electronics, faster readout and easier post processing. It is also flexible with sampling rate and pixel throughput while maintaining the core circuit topology intact. Noise characterization of the IDSAC CDS signal chain has been performed by analytical modelling and practical measurements. Various types of noise such as white, pink, power supply, bias etc. has been considered while creating an analytical noise model tool to predict noise of a controller system like IDSAC. Several tests are performed to measure the actual noise of IDSAC. The theoretical calculation matches very well with practical measurements within 10% accuracy.

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 CCD Monolithic LMS Adaptive Analog Signal Processor Integrated Circuit.

DTIC Science & Technology

1980-03-01

adaptive filter with electrically- reprogrammable MOS analog conductance weights. I The analog and digital peripheral MOS on-chip circuits are provided with...electrically reprogrammable analog weights at tap positions along a CCD analog delay line in order to form a basic linear combiner for adaptive filtering...electrically reprogrammable analog conductance weights was introduced with the use of non-volatile MNOS memory 6-7 transistors biased in their triode

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.

Fast noninvasive eye-tracking and eye-gaze determination for biomedical and remote monitoring applications

NASA Astrophysics Data System (ADS)

Talukder, Ashit; Morookian, John M.; Monacos, Steve P.; Lam, Raymond K.; Lebaw, C.; Bond, A.

2004-04-01

Eyetracking is one of the latest technologies that has shown potential in several areas including human-computer interaction for people with and without disabilities, and for noninvasive monitoring, detection, and even diagnosis of physiological and neurological problems in individuals. Current non-invasive eyetracking methods achieve a 30 Hz rate with possibly low accuracy in gaze estimation, that is insufficient for many applications. We propose a new non-invasive visual eyetracking system that is capable of operating at speeds as high as 6-12 KHz. A new CCD video camera and hardware architecture is used, and a novel fast image processing algorithm leverages specific features of the input CCD camera to yield a real-time eyetracking system. A field programmable gate array (FPGA) is used to control the CCD camera and execute the image processing operations. Initial results show the excellent performance of our system under severe head motion and low contrast conditions.

Aerosol mobility imaging for rapid size distribution measurements

DOEpatents

Wang, Jian; Hering, Susanne Vera; Spielman, Steven Russel; Kuang, Chongai

2016-07-19

A parallel plate dimensional electrical mobility separator and laminar flow water condensation provide rapid, mobility-based particle sizing at concentrations typical of the remote atmosphere. Particles are separated spatially within the electrical mobility separator, enlarged through water condensation, and imaged onto a CCD array. The mobility separation distributes particles in accordance with their size. The condensation enlarges size-separated particles by water condensation while they are still within the gap of the mobility drift tube. Once enlarged the particles are illuminated by a laser. At a pre-selected frequency, typically 10 Hz, the position of all of the individual particles illuminated by the laser are captured by CCD camera. This instantly records the particle number concentration at each position. Because the position is directly related to the particle size (or mobility), the particle size spectra is derived from the images recorded by the CCD.

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.

MTF measurement of LCDs by a linear CCD imager: I. Monochrome case

NASA Astrophysics Data System (ADS)

Kim, Tae-hee; Choe, O. S.; Lee, Yun Woo; Cho, Hyun-Mo; Lee, In Won

1997-11-01

We construct the modulation transfer function (MTF) measurement system of a LCD using a linear charge-coupled device (CCD) imager. The MTF used in optical system can not describe in the effect of both resolution and contrast on the image quality of display. Thus we present the new measurement method based on the transmission property of a LCD. While controlling contrast and brightness levels, the MTF is measured. From the result, we show that the method is useful for describing of the image quality. A ne measurement method and its condition are described. To demonstrate validity, the method is applied for comparison of the performance of two different LCDs.

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.

Cat-eye effect reflected beam profiles of an optical system with sensor array.

PubMed

Gong, Mali; He, Sifeng; Guo, Rui; Wang, Wei

2016-06-01

In this paper, we propose an applicable propagation model for Gaussian beams passing through any cat-eye target instead of traditional simplification consisting of only a mirror placed at the focal plane of a lens. According to the model, the cat-eye effect of CCD cameras affected by defocus is numerically simulated. An excellent agreement of experiment results with theoretical analysis is obtained. It is found that the reflectivity distribution at the focal plane of the cat-eye optical lens has great influence on the results, while the cat-eye effect reflected beam profiles of CCD cameras show obvious periodicity.

Smart photodetector arrays for error control in page-oriented optical memory

NASA Astrophysics Data System (ADS)

Schaffer, Maureen Elizabeth

1998-12-01

Page-oriented optical memories (POMs) have been proposed to meet high speed, high capacity storage requirements for input/output intensive computer applications. This technology offers the capability for storage and retrieval of optical data in two-dimensional pages resulting in high throughput data rates. Since currently measured raw bit error rates for these systems fall several orders of magnitude short of industry requirements for binary data storage, powerful error control codes must be adopted. These codes must be designed to take advantage of the two-dimensional memory output. In addition, POMs require an optoelectronic interface to transfer the optical data pages to one or more electronic host systems. Conventional charge coupled device (CCD) arrays can receive optical data in parallel, but the relatively slow serial electronic output of these devices creates a system bottleneck thereby eliminating the POM advantage of high transfer rates. Also, CCD arrays are "unintelligent" interfaces in that they offer little data processing capabilities. The optical data page can be received by two-dimensional arrays of "smart" photo-detector elements that replace conventional CCD arrays. These smart photodetector arrays (SPAs) can perform fast parallel data decoding and error control, thereby providing an efficient optoelectronic interface between the memory and the electronic computer. This approach optimizes the computer memory system by combining the massive parallelism and high speed of optics with the diverse functionality, low cost, and local interconnection efficiency of electronics. In this dissertation we examine the design of smart photodetector arrays for use as the optoelectronic interface for page-oriented optical memory. We review options and technologies for SPA fabrication, develop SPA requirements, and determine SPA scalability constraints with respect to pixel complexity, electrical power dissipation, and optical power limits. Next, we examine data modulation and error correction coding for the purpose of error control in the POM system. These techniques are adapted, where possible, for 2D data and evaluated as to their suitability for a SPA implementation in terms of BER, code rate, decoder time and pixel complexity. Our analysis shows that differential data modulation combined with relatively simple block codes known as array codes provide a powerful means to achieve the desired data transfer rates while reducing error rates to industry requirements. Finally, we demonstrate the first smart photodetector array designed to perform parallel error correction on an entire page of data and satisfy the sustained data rates of page-oriented optical memories. Our implementation integrates a monolithic PN photodiode array and differential input receiver for optoelectronic signal conversion with a cluster error correction code using 0.35-mum CMOS. This approach provides high sensitivity, low electrical power dissipation, and fast parallel correction of 2 x 2-bit cluster errors in an 8 x 8 bit code block to achieve corrected output data rates scalable to 102 Gbps in the current technology increasing to 1.88 Tbps in 0.1-mum CMOS.

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.

Fast Confocal Raman Imaging Using a 2-D Multifocal Array for Parallel Hyperspectral Detection.

PubMed

Kong, Lingbo; Navas-Moreno, Maria; Chan, James W

2016-01-19

We present the development of a novel confocal hyperspectral Raman microscope capable of imaging at speeds up to 100 times faster than conventional point-scan Raman microscopy under high noise conditions. The microscope utilizes scanning galvomirrors to generate a two-dimensional (2-D) multifocal array at the sample plane, generating Raman signals simultaneously at each focus of the array pattern. The signals are combined into a single beam and delivered through a confocal pinhole before being focused through the slit of a spectrometer. To separate the signals from each row of the array, a synchronized scan mirror placed in front of the spectrometer slit positions the Raman signals onto different pixel rows of the detector. We devised an approach to deconvolve the superimposed signals and retrieve the individual spectra at each focal position within a given row. The galvomirrors were programmed to scan different focal arrays following Hadamard encoding patterns. A key feature of the Hadamard detection is the reconstruction of individual spectra with improved signal-to-noise ratio. Using polystyrene beads as test samples, we demonstrated not only that our system images faster than a conventional point-scan method but that it is especially advantageous under noisy conditions, such as when the CCD detector operates at fast read-out rates and high temperatures. This is the first demonstration of multifocal confocal Raman imaging in which parallel spectral detection is implemented along both axes of the CCD detector chip. We envision this novel 2-D multifocal spectral detection technique can be used to develop faster imaging spontaneous Raman microscopes with lower cost detectors.

Functional characterisation of three members of the Vitis vinifera L. carotenoid cleavage dioxygenase gene family

PubMed Central

2013-01-01

Background In plants, carotenoids serve as the precursors to C13-norisoprenoids, a group of apocarotenoid compounds with diverse biological functions. Enzymatic cleavage of carotenoids catalysed by members of the carotenoid cleavage dioxygenase (CCD) family has been shown to produce a number of industrially important volatile flavour and aroma apocarotenoids including β-ionone, geranylacetone, pseudoionone, α-ionone and 3-hydroxy-β-ionone in a range of plant species. Apocarotenoids contribute to the floral and fruity attributes of many wine cultivars and are thereby, at least partly, responsible for the “varietal character”. Despite their importance in grapes and wine; carotenoid cleavage activity has only been described for VvCCD1 and the mechanism(s) and regulation of carotenoid catabolism remains largely unknown. Results Three grapevine-derived CCD-encoding genes have been isolated and shown to be functional with unique substrate cleavage capacities. Our results demonstrate that the VvCCD4a and VvCCD4b catalyse the cleavage of both linear and cyclic carotenoid substrates. The expression of VvCCD1, VvCCD4a and VvCCD4b was detected in leaf, flower and throughout berry development. VvCCD1 expression was constitutive, whereas VvCCD4a expression was predominant in leaves and VvCCD4b in berries. A transgenic population with a 12-fold range of VvCCD1 expression exhibited a lack of correlation between VvCCD1 expression and carotenoid substrates and/or apocarotenoid products in leaves, providing proof that the in planta function(s) of VvCCD1 in photosynthetically active tissue is distinct from the in vitro activities demonstrated. The isolation and functional characterisation of VvCCD4a and VvCCD4b identify two additional CCDs that are functional in grapevine. Conclusions Taken together, our results indicate that the three CCDs are under various levels of control that include gene expression (spatial and temporal), substrate specificity and compartmentalisation that act individually and/or co-ordinately to maintain carotenoid and volatile apocarotenoid levels in plants. Altering the expression of VvCCD1 in a transgenic grapevine population illustrated the divergence between the in vitro enzyme activity and the in planta activity of this enzyme, thereby contributing to the efforts to understand how enzymatic degradation of carotenoids involved in photosynthesis occurs. The identification and functional characterisation of VvCCD4a and VvCCD4b suggest that these enzymes are primarily responsible for catalysing the cleavage of plastidial carotenoids. PMID:24106789

Mercury cadmium telluride infrared detector development in India: status and issues

NASA Astrophysics Data System (ADS)

Singh, R. N.

2009-05-01

In the present paper, we describe the development of Long Wave Infrared (8-12 μm) linear and 2-D IR FPA detectors using HgCdTe for use in thermal imagers and IIR seekers. In this direction, Solid State Physics Laboratory(SSPL) (DRDO) tried to concentrate initially in the bulk growth and characterization of HgCdTe during the early eighties. Some efforts were then made to develop a LWIR photoconductive type MCT array in linear configuration with the IRFPA processed on bulk MCT crystals grown in the laboratory. Non availability of quality epilayers with the required specification followed by the denial of supply of CdTe, CdZnTe and even high purity Te by advanced countries, forced us to shift our efforts during early nineties towards development of 60 element PC IR detectors. High performance linear PC arrays were developed. A novel horizontal casting procedure was evolved for growing high quality bulk material using solid state recrystallization technique. Efforts for ultra purification of Te to 7N purity with the help of a sister concern has made it possible to have this material indigenously. Having succeded in the technology for growing single crystalline CdZnTe with (111) orientation and LPE growth of HgCdTe epilayers on CdZnTe substrates an attempt was made to establish the fabrication of 2D short PV arrays showing significant IR response. Thus a detailed technological knowhow for passivation, metallization, ion implanted junction formation, etc. was generated. Parallel work on the development of a matching CCD Mux readout in silicon by Semiconductor Complex Limited was also completed which was tested first in stand-alone mode followed by integration with IRFPAs through indigenously-developed indium bumps. These devices were integrated into an indigenously fabricated glass dewar cooled by a self-developed JT minicooler. In recent years, the LPE (Liquid Phase Epitaxy) growth from Terich route has been standardized for producing epitaxial layers with high compositional and thickness uniformity leading to a respectable stage of maturity in FPA technology.

Assessment of tissue viability by polarization spectroscopy

NASA Astrophysics Data System (ADS)

Nilsson, G.; Anderson, C.; Henricson, J.; Leahy, M.; O'Doherty, J.; Sjöberg, F.

2008-09-01

A new and versatile method for tissue viability imaging based on polarization spectroscopy of blood in superficial tissue structures such as the skin is presented in this paper. Linearly polarized light in the visible wavelength region is partly reflected directly by the skin surface and partly diffusely backscattered from the dermal tissue matrix. Most of the directly reflected light preserves its polarization state while the light returning from the deeper tissue layers is depolarized. By the use of a polarization filter positioned in front of a sensitive CCD-array, the light directly reflected from the tissue surface is blocked, while the depolarized light returning from the deeper tissue layers reaches the detector array. By separating the colour planes of the detected image, spectroscopic information about the amount of red blood cells (RBCs) in the microvascular network of the tissue under investigation can be derived. A theory that utilizes the differences in light absorption of RBCs and bloodless tissue in the red and green wavelength region forms the basis of an algorithm for displaying a colour coded map of the RBC distribution in a tissue. Using a fluid model, a linear relationship (cc. = 0.99) between RBC concentration and the output signal was demonstrated within the physiological range 0-4%. In-vivo evaluation using transepidermal application of acetylcholine by the way of iontophoresis displayed the heterogeneity pattern of the vasodilatation produced by the vasoactive agent. Applications of this novel technology are likely to be found in drug and skin care product development as well as in the assessment of skin irritation and tissue repair processes and even ultimately in a clinic case situation.

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.

A portable array biosensor for food safety

NASA Astrophysics Data System (ADS)

Golden, Joel P.; Ngundi, Miriam M.; Shriver-Lake, Lisa C.; Taitt, Chris R.; Ligler, Frances S.

2004-11-01

An array biosensor developed for simultaneous analysis of multiple samples has been utilized to develop assays for toxins and pathogens in a variety of foods. The biochemical component of the multi-analyte biosensor consists of a patterned array of biological recognition elements immobilized on the surface of a planar waveguide. A fluorescence assay is performed on the patterned surface, yielding an array of fluorescent spots, the locations of which are used to identify what analyte is present. Signal transduction is accomplished by means of a diode laser for fluorescence excitation, optical filters and a CCD camera for image capture. A laptop computer controls the miniaturized fluidics system and image capture. Results for four mycotoxin competition assays in buffer and food samples are presented.

SU-F-T-180: Evaluation of a Scintillating Screen Detector for Proton Beam QA and Acceptance Testing

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

Ghebremedhin, A; Taber, M; Koss, P

2016-06-15

Purpose: To test the performance of a commercial scintillating screen detector for acceptance testing and Quality Assurance of a proton pencil beam scanning system. Method: The detector (Lexitek DRD 400) has 40cm × 40cm field, uses a thin scintillator imaged onto a 16-bit scientific CCD with ∼0.5mm resolution. A grid target and LED illuminators are provided for spatial calibration and relative gain correction. The detector mounts to the nozzle with micron precision. Tools are provided for image processing and analysis of single or multiple Gaussian spots. Results: The bias and gain of the detector were studied to measure repeatability andmore » accuracy. Gain measurements were taken with the LED illuminators to measure repeatability and variation of the lens-CCD pair as a function with f-stop. Overall system gain was measured with a passive scattering (broad) beam whose shape is calibrated with EDR film placed in front of the scintillator. To create a large uniform field, overlapping small fields were recorded with the detector translated laterally and stitched together to cover the full field. Due to the long exposures required to obtain multiple spills of the synchrotron and very high detector sensitivity, borated polyethylene shielding was added to reduce direct radiation events hitting the CCD. Measurements with a micro ion chamber were compared to the detector’s spot profile. Software was developed to process arrays of Gaussian spots and to correct for radiation events. Conclusion: The detector background has a fixed bias, a small component linear in time, and is easily corrected. The gain correction method was validated with 2% accuracy. The detector spot profile matches the micro ion chamber data over 4 orders of magnitude. The multiple spot analyses can be easily used with plan data for measuring pencil beam uniformity and for regular QA comparison.« less

Onboard TDI stage estimation and calibration using SNR analysis

NASA Astrophysics Data System (ADS)

Haghshenas, Javad

2017-09-01

Electro-Optical design of a push-broom space camera for a Low Earth Orbit (LEO) remote sensing satellite is performed based on the noise analysis of TDI sensors for very high GSDs and low light level missions. It is well demonstrated that the CCD TDI mode of operation provides increased photosensitivity relative to a linear CCD array, without the sacrifice of spatial resolution. However, for satellite imaging, in order to utilize the advantages which the TDI mode of operation offers, attention should be given to the parameters which affect the image quality of TDI sensors such as jitters, vibrations, noises and etc. A predefined TDI stages may not properly satisfy image quality requirement of the satellite camera. Furthermore, in order to use the whole dynamic range of the sensor, imager must be capable to set the TDI stages in every shots based on the affecting parameters. This paper deals with the optimal estimation and setting the stages based on tradeoffs among MTF, noises and SNR. On-board SNR estimation is simulated using the atmosphere analysis based on the MODTRAN algorithm in PcModWin software. According to the noises models, we have proposed a formulation to estimate TDI stages in such a way to satisfy the system SNR requirement. On the other hand, MTF requirement must be satisfy in the same manner. A proper combination of both parameters will guaranty the full dynamic range usage along with the high SNR and image quality.

The multisensor payload 'Structura' for the observation of atmospheric night glows from the ISS board

NASA Astrophysics Data System (ADS)

Krot, Yury; Beliaev, Boris; Katkovsky, Leonid

2016-10-01

Aerospace Research Department of the Institute of Applied Physical Problems at Belarusian State University has developed a prototype of the optical payload intended for a space experiment on the ISS board. The prototype includes four optical modules for the night glows observation, in particular spatial-brightness and spectral characteristics in the altitude range of 80-320 km. Objects of the interest are emitting top layers of the atmosphere including exited OH radicals, atomic and molecular oxygen and sodium layers. The goal of the space experiment is a research of night glows over different regions of the Earth and a connection with natural disasters like earthquakes, cyclones, etc. Two optical modules for spatial distribution of atomic oxygen layers along the altitude consist of input lenses, spectral interferential filters and line CCD detectors. The optical module for registration of exited OH radical emissions is formed from CCD array spectrometer. The payload includes also a panchromatic (400-900 nm) high sensitive imaging camera for observing of the glows general picture. The optical modules of the prototype have been tested and general optical characteristics were determined in laboratory conditions. A solution of an astigmatism reducing of a concave diffraction grating and a method of the second diffraction order correction were applied and improved spectrometer's optical characteristics. Laboratory equipment and software were developed to imitate a dynamic scene of the night glows in laboratory conditions including an imitation of linear spectra and the spatial distribution of emissions.

The application of charge-coupled device processors in automatic-control systems

NASA Technical Reports Server (NTRS)

Mcvey, E. S.; Parrish, E. A., Jr.

1977-01-01

The application of charge-coupled device (CCD) processors to automatic-control systems is suggested. CCD processors are a new form of semiconductor component with the unique ability to process sampled signals on an analog basis. Specific implementations of controllers are suggested for linear time-invariant, time-varying, and nonlinear systems. Typical processing time should be only a few microseconds. This form of technology may become competitive with microprocessors and minicomputers in addition to supplementing them.

Multiple-target tracking implementation in the ebCMOS camera system: the LUSIPHER prototype

NASA Astrophysics Data System (ADS)

Doan, Quang Tuyen; Barbier, Remi; Dominjon, Agnes; Cajgfinger, Thomas; Guerin, Cyrille

2012-06-01

The domain of the low light imaging systems progresses very fast, thanks to detection and electronic multiplication technology evolution, such as the emCCD (electron multiplying CCD) or the ebCMOS (electron bombarded CMOS). We present an ebCMOS camera system that is able to track every 2 ms more than 2000 targets with a mean number of photons per target lower than two. The point light sources (targets) are spots generated by a microlens array (Shack-Hartmann) used in adaptive optics. The Multiple-Target-Tracking designed and implemented on a rugged workstation is described. The results and the performances of the system on the identification and tracking are presented and discussed.

Characterization of multiport solid state imagers at megahertz data rates

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

Yates, G.J.; Pena, C.R.; Turko, B.T.

1994-08-01

Test results obtained from two recently developed multiport Charge-Coupled Devices (CCDs) operated at pixel rates in the 10-to-100 MHz range will be presented . The CCDs were evaluated in Los Alamos National Laboratory`s High Speed Solid State Imager Test Station (HSTS) which features PC-based programmable clock waveform generation (Tektronix DAS 9200) and synchronously clocked Digital Sampling Oscilloscopes (DSOs) (LeCroy 9424/9314 series) for CCD pixel data acquisition, analysis and storage. The HSTS also provided special designed optical pinhole array test patterns in the 5-to-50 micron diameter range for use with Xenon Strobe and pulsed laser light sources to simultaneously provide multiplemore » single-pixel illumination patterns to study CCD point-spread-function (PSF) and pixel smear characteristics. The two CCDs tested, EEV model CCD-13 and EG&G Reticon model HSO512J, are both 512 {times} 512 pixel arrays with eight (8) and sixteen (16) video output ports respectively. Both devices are generically Frame Transfer CCDs (FT CCDs) designed for parallel bi-directional vertical readout to augment their multiport design for increased pixel rates over common single port serial readout architecture. Although both CCDs were tested similarly, differences in their designs precluded normalization or any direct comparisons of test results. Rate dependent parameters investigated include S/N, PSF, and MTF. The performance observed for the two imagers at various pixel rates from selected typical output ports is discussed.« less

Small-angle solution scattering using the mixed-mode pixel array detector.

PubMed

Koerner, Lucas J; Gillilan, Richard E; Green, Katherine S; Wang, Suntao; Gruner, Sol M

2011-03-01

Solution small-angle X-ray scattering (SAXS) measurements were obtained using a 128 × 128 pixel X-ray mixed-mode pixel array detector (MMPAD) with an 860 µs readout time. The MMPAD offers advantages for SAXS experiments: a pixel full-well of >2 × 10(7) 10 keV X-rays, a maximum flux rate of 10(8) X-rays pixel(-1) s(-1), and a sub-pixel point-spread function. Data from the MMPAD were quantitatively compared with data from a charge-coupled device (CCD) fiber-optically coupled to a phosphor screen. MMPAD solution SAXS data from lysozyme solutions were of equal or better quality than data captured by the CCD. The read-noise (normalized by pixel area) of the MMPAD was less than that of the CCD by an average factor of 3.0. Short sample-to-detector distances were required owing to the small MMPAD area (19.2 mm × 19.2 mm), and were revealed to be advantageous with respect to detector read-noise. As predicted by the Shannon sampling theory and confirmed by the acquisition of lysozyme solution SAXS curves, the MMPAD at short distances is capable of sufficiently sampling a solution SAXS curve for protein shape analysis. The readout speed of the MMPAD was demonstrated by continuously monitoring lysozyme sample evolution as radiation damage accumulated. These experiments prove that a small suitably configured MMPAD is appropriate for time-resolved solution scattering measurements.

Small-angle solution scattering using the mixed-mode pixel array detector

PubMed Central

Koerner, Lucas J.; Gillilan, Richard E.; Green, Katherine S.; Wang, Suntao; Gruner, Sol M.

2011-01-01

Solution small-angle X-ray scattering (SAXS) measurements were obtained using a 128 × 128 pixel X-ray mixed-mode pixel array detector (MMPAD) with an 860 µs readout time. The MMPAD offers advantages for SAXS experiments: a pixel full-well of >2 × 107 10 keV X-rays, a maximum flux rate of 108 X-rays pixel−1 s−1, and a sub-pixel point-spread function. Data from the MMPAD were quantitatively compared with data from a charge-coupled device (CCD) fiber-optically coupled to a phosphor screen. MMPAD solution SAXS data from lysozyme solutions were of equal or better quality than data captured by the CCD. The read-noise (normalized by pixel area) of the MMPAD was less than that of the CCD by an average factor of 3.0. Short sample-to-detector distances were required owing to the small MMPAD area (19.2 mm × 19.2 mm), and were revealed to be advantageous with respect to detector read-noise. As predicted by the Shannon sampling theory and confirmed by the acquisition of lysozyme solution SAXS curves, the MMPAD at short distances is capable of sufficiently sampling a solution SAXS curve for protein shape analysis. The readout speed of the MMPAD was demonstrated by continuously monitoring lysozyme sample evolution as radiation damage accumulated. These experiments prove that a small suitably configured MMPAD is appropriate for time-resolved solution scattering measurements. PMID:21335900

The readout and control system of the mid-size telescope prototype of the Cherenkov Telescope Array

NASA Astrophysics Data System (ADS)

Oya, I.; Anguner, O.; Behera, B.; Birsin, E.; Fuessling, M.; Melkumyan, D.; Schmidt, T.; Schwanke, U.; Sternberger, R.; Wegner, P.; Wiesand, S.; Cta Consortium,the

2014-06-01

The Cherenkov Telescope Array (CTA) is one of the major ground-based astronomy projects being pursued and will be the largest facility for ground-based y-ray observations ever built. CTA will consist of two arrays: one in the Northern hemisphere composed of about 20 telescopes, and the other one in the Southern hemisphere composed of about 100 telescopes, both arrays containing telescopes of different type and size. A prototype for the Mid-Size Telescope (MST) with a diameter of 12 m has been installed in Berlin and is currently being commissioned. This prototype is composed of a mechanical structure, a drive system and mirror facets mounted with powered actuators to enable active control. Five Charge-Coupled Device (CCD) cameras, and a wide set of sensors allow the evaluation of the performance of the instrument. The design of the control software is following concepts and tools under evaluation within the CTA consortium in order to provide a realistic test-bed for the middleware: 1) The readout and control system for the MST prototype is implemented with the Atacama Large Millimeter/submillimeter Array (ALMA) Common Software (ACS) distributed control middleware; 2) the OPen Connectivity-Unified Architecture (OPC UA) is used for hardware access; 3) the document oriented MongoDB database is used for an efficient storage of CCD images, logging and alarm information: and 4) MySQL and MongoDB databases are used for archiving the slow control monitoring data and for storing the operation configuration parameters. In this contribution, the details of the implementation of the control system for the MST prototype telescope are described.

Calibrating Images from the MINERVA Cameras

NASA Astrophysics Data System (ADS)

Mercedes Colón, Ana

2016-01-01

The MINiature Exoplanet Radial Velocity Array (MINERVA) consists of an array of robotic telescopes located on Mount Hopkins, Arizona with the purpose of performing transit photometry and spectroscopy to find Earth-like planets around Sun-like stars. In order to make photometric observations, it is necessary to perform calibrations on the CCD cameras of the telescopes to take into account possible instrument error on the data. In this project, we developed a pipeline that takes optical images, calibrates them using sky flats, darks, and biases to generate a transit light curve.

Diffraction mode terahertz tomography

DOEpatents

Ferguson, Bradley; Wang, Shaohong; Zhang, Xi-Cheng

2006-10-31

A method of obtaining a series of images of a three-dimensional object. The method includes the steps of transmitting pulsed terahertz (THz) radiation through the entire object from a plurality of angles, optically detecting changes in the transmitted THz radiation using pulsed laser radiation, and constructing a plurality of imaged slices of the three-dimensional object using the detected changes in the transmitted THz radiation. The THz radiation is transmitted through the object as a two-dimensional array of parallel rays. The optical detection is an array of detectors such as a CCD sensor.

Enhanced radiation detectors using luminescent materials

DOEpatents

Vardeny, Zeev V.; Jeglinski, Stefan A.; Lane, Paul A.

2001-01-01

A radiation detecting device comprising a radiation sensing element, and a layer of luminescent material to expand the range of wavelengths over which the sensing element can efficiently detect radiation. The luminescent material being selected to absorb radiation at selected wavelengths, causing the luminescent material to luminesce, and the luminescent radiation being detected by the sensing element. Radiation sensing elements include photodiodes (singly and in arrays), CCD arrays, IR detectors and photomultiplier tubes. Luminescent materials include polymers, oligomers, copolymers and porphyrines, Luminescent layers include thin films, thicker layers, and liquid polymers.

Injection of a coaxial-gun-produced magnetized plasma into a background helicon plasma

NASA Astrophysics Data System (ADS)

Zhang, Yue; Lynn, Alan; Gilmore, Mark; Hsu, Scott

2014-10-01

A compact coaxial plasma gun is employed for experimental investigation of plasma bubble relaxation into a lower density background plasma. Experiments are being conducted in the linear device HelCat at UNM. The gun is powered by a 120-uF ignitron-switched capacitor bank, which is operated in a range of 5 to 10 kV and 100 kA. Multiple diagnostics are employed to investigate the plasma relaxation process. Magnetized argon plasma bubbles with velocities 1.2Cs, densities 1020 m-3 and electron temperature 13eV have been achieved. The background helicon plasma has density 1013 m-3, magnetic field from 200 to 500 Gauss and electron temperature 1eV. Several distinct operational regimes with qualitatively different dynamics are identified by fast CCD camera images. Additionally a B-dot probe array has been employed to measure the spatial toroidal and poloidal magnetic flux evolution to identify plasma bubble configurations. Experimental data and analysis will be presented.

A pepper-pot emittance meter for low-energy heavy-ion beams

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

Kremers, H. R.; Beijers, J. P. M.; Brandenburg, S.

2013-02-15

A novel emittance meter has been developed to measure the four-dimensional, transverse phase-space distribution of a low-energy ion beam using the pepper-pot technique. A characteristic feature of this instrument is that the pepper-pot plate, which has a linear array of holes in the vertical direction, is scanned horizontally through the ion beam. This has the advantage that the emittance can also be measured at locations along the beam line where the beam has a large horizontal divergence. A set of multi-channel plates, scintillation screen, and ccd camera is used as a position-sensitive ion detector allowing a large range of beammore » intensities that can be handled. This paper describes the design, construction, and operation of the instrument as well as the data analysis used to reconstruct the four-dimensional phase-space distribution of an ion beam. Measurements on a 15 keV He{sup +} beam are used as an example.« less

DAMIC at SNOLAB

DOE PAGES

Chavarria, Alvaro E.; Tiffenberg, Javier; Aguilar-Arevalo, Alexis; ...

2015-03-24

We introduce the fully-depleted charge-coupled device (CCD) as a particle detector. We demonstrate its low energy threshold operation, capable of detecting ionizing energy depositions in a single pixel down to 50 eV ee. We present results of energy calibrations from 0.3 keV ee to 60 ke Vee, showing that the CCD is a fully active detector with uniform energy response throughout the silicon target, good resolution (Fano ~0.16), and remarkable linear response to electron energy depositions. We show the capability of the CCD to localize the depth of particle interactions within the silicon target. We discuss the mode of operationmore » and unique imaging capabilities of the CCD, and how they may be exploited to characterize and suppress backgrounds. We present the first results from the deployment of 250 μm thick CCDs in SNOLAB, a prototype for the upcoming DAMIC100. DAMIC100 will have a target mass of 0.1 kg and should be able to directly test the CDMS-Si signal within a year of operation.« less

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.

Ultra compact spectrometer using linear variable filters

NASA Astrophysics Data System (ADS)

Dami, M.; De Vidi, R.; Aroldi, G.; Belli, F.; Chicarella, L.; Piegari, A.; Sytchkova, A.; Bulir, J.; Lemarquis, F.; Lequime, M.; Abel Tibérini, L.; Harnisch, B.

2017-11-01

The Linearly Variable Filters (LVF) are complex optical devices that, integrated in a CCD, can realize a "single chip spectrometer". In the framework of an ESA Study, a team of industries and institutes led by SELEX-Galileo explored the design principles and manufacturing techniques, realizing and characterizing LVF samples based both on All-Dielectric (AD) and Metal-Dielectric (MD) Coating Structures in the VNIR and SWIR spectral ranges. In particular the achieved performances on spectral gradient, transmission bandwidth and Spectral Attenuation (SA) are presented and critically discussed. Potential improvements will be highlighted. In addition the results of a feasibility study of a SWIR Linear Variable Filter are presented with the comparison of design prediction and measured performances. Finally criticalities related to the filter-CCD packaging are discussed. The main achievements reached during these activities have been: - to evaluate by design, manufacturing and test of LVF samples the achievable performances compared with target requirements; - to evaluate the reliability of the projects by analyzing their repeatability; - to define suitable measurement methodologies

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

Solid state high resolution multi-spectral imager CCD test phase

NASA Technical Reports Server (NTRS)

1973-01-01

The program consisted of measuring the performance characteristics of charge coupled linear imaging devices, and a study defining a multispectral imaging system employing advanced solid state photodetection techniques.

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.

Rigorous Photogrammetric Processing of CHANG'E-1 and CHANG'E-2 Stereo Imagery for Lunar Topographic Mapping

NASA Astrophysics Data System (ADS)

Di, K.; Liu, Y.; Liu, B.; Peng, M.

2012-07-01

Chang'E-1(CE-1) and Chang'E-2(CE-2) are the two lunar orbiters of China's lunar exploration program. Topographic mapping using CE-1 and CE-2 images is of great importance for scientific research as well as for preparation of landing and surface operation of Chang'E-3 lunar rover. In this research, we developed rigorous sensor models of CE-1 and CE-2 CCD cameras based on push-broom imaging principle with interior and exterior orientation parameters. Based on the rigorous sensor model, the 3D coordinate of a ground point in lunar body-fixed (LBF) coordinate system can be calculated by space intersection from the image coordinates of con-jugate points in stereo images, and the image coordinates can be calculated from 3D coordinates by back-projection. Due to uncer-tainties of the orbit and the camera, the back-projected image points are different from the measured points. In order to reduce these inconsistencies and improve precision, we proposed two methods to refine the rigorous sensor model: 1) refining EOPs by correcting the attitude angle bias, 2) refining the interior orientation model by calibration of the relative position of the two linear CCD arrays. Experimental results show that the mean back-projection residuals of CE-1 images are reduced to better than 1/100 pixel by method 1 and the mean back-projection residuals of CE-2 images are reduced from over 20 pixels to 0.02 pixel by method 2. Consequently, high precision DEM (Digital Elevation Model) and DOM (Digital Ortho Map) are automatically generated.

Charge coupled devices

NASA Technical Reports Server (NTRS)

Walker, J. W.; Hornbeck, L. J.; Stubbs, D. P.

1977-01-01

The results are presented of a program to design, fabricate, and test CCD arrays suitable for operation in an electron-bombarded mode. These intensified charge coupled devices have potential application to astronomy as photon-counting arrays. The objectives of this program were to deliver arrays of 250 lines of 400 pixels each and some associated electronics. Some arrays were delivered on tube-compatible headers and some were delivered after incorporation in vacuum tubes. Delivery of these devices required considerable improvements to be made in the processing associated with intensified operation. These improvements resulted in a high yield in the thinning process, reproducible results in the accumulation process, elimination of a dark current source in the accumulation process, solution of a number of header related problems, and the identification of a remaining major source of dark current. Two systematic failure modes were identified and protective measures established. The effects of tube processing on the arrays in the delivered ICCDs were determined and are reported along with the characterization data on the arrays.

Three-dimensional shape measurement and calibration for fringe projection by considering unequal height of the projector and the camera

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

Zhu Feipeng; Shi Hongjian; Bai Pengxiang

In fringe projection, the CCD camera and the projector are often placed at equal height. In this paper, we will study the calibration of an unequal arrangement of the CCD camera and the projector. The principle of fringe projection with two-dimensional digital image correlation to acquire the profile of object surface is described in detail. By formula derivation and experiment, the linear relationship between the out-of-plane calibration coefficient and the y coordinate is clearly found. To acquire the three-dimensional (3D) information of an object correctly, this paper presents an effective calibration method with linear least-squares fitting, which is very simplemore » in principle and calibration. Experiments are implemented to validate the availability and reliability of the calibration method.« less

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.

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.

Near-infrared fluorescence imaging with a mobile phone (Conference Presentation)

NASA Astrophysics Data System (ADS)

Ghassemi, Pejhman; Wang, Bohan; Wang, Jianting; Wang, Quanzeng; Chen, Yu; Pfefer, T. Joshua

2017-03-01

Mobile phone cameras employ sensors with near-infrared (NIR) sensitivity, yet this capability has not been exploited for biomedical purposes. Removing the IR-blocking filter from a phone-based camera opens the door to a wide range of techniques and applications for inexpensive, point-of-care biophotonic imaging and sensing. This study provides proof of principle for one of these modalities - phone-based NIR fluorescence imaging. An imaging system was assembled using a 780 nm light source along with excitation and emission filters with 800 nm and 825 nm cut-off wavelengths, respectively. Indocyanine green (ICG) was used as an NIR fluorescence contrast agent in an ex vivo rodent model, a resolution test target and a 3D-printed, tissue-simulating vascular phantom. Raw and processed images for red, green and blue pixel channels were analyzed for quantitative evaluation of fundamental performance characteristics including spectral sensitivity, detection linearity and spatial resolution. Mobile phone results were compared with a scientific CCD. The spatial resolution of CCD system was consistently superior to the phone, and green phone camera pixels showed better resolution than blue or green channels. The CCD exhibited similar sensitivity as processed red and blue pixels channels, yet a greater degree of detection linearity. Raw phone pixel data showed lower sensitivity but greater linearity than processed data. Overall, both qualitative and quantitative results provided strong evidence of the potential of phone-based NIR imaging, which may lead to a wide range of applications from cancer detection to glucose sensing.

NGS2: a focal plane array upgrade for the GeMS multiple tip-tilt wavefront sensor

NASA Astrophysics Data System (ADS)

Rigaut, François; Price, Ian; d'Orgeville, Céline; Bennet, Francis; Herrald, Nick; Paulin, Nicolas; Uhlendorf, Kristina; Garrel, Vincent; Sivo, Gaetano; Montes, Vanessa; Trujillo, Chad

2016-07-01

NGS2 is an upgrade for the multi-natural guide star tip-tilt & plate scale wavefront sensor for GeMS (Gemini Multi-Conjugate Adaptive Optics system). It uses a single Nüvü HNü-512 Electron-Multiplied CCD array that spans the entire GeMS wavefront sensor focal plane. Multiple small regions-of-interest are used to enable frame rates up to 800Hz. This set up will improve the optical throughput with respect to the current wavefront sensor, as well as streamline acquisition and allow for distortion compensation.

Living Matter Observations with a Novel Hyperspectral Supercontinuum Confocal Microscope for VIS to Near-IR Reflectance Spectroscopy

PubMed Central

Bertani, Francesca R.; Ferrari, Luisa; Mussi, Valentina; Botti, Elisabetta; Costanzo, Antonio; Selci, Stefano

2013-01-01

A broad range hyper-spectroscopic microscope fed by a supercontinuum laser source and equipped with an almost achromatic optical layout is illustrated with detailed explanations of the design, implementation and data. The real novelty of this instrument, a confocal spectroscopic microscope capable of recording high resolution reflectance data in the VIS-IR spectral range from about 500 nm to 2.5 μm wavelengths, is the possibility of acquiring spectral data at every physical point as defined by lateral coordinates, X and Y, as well as at a depth coordinate, Z, as obtained by the confocal optical sectioning advantage. With this apparatus we collect each single scanning point as a whole spectrum by combining two linear spectral detector arrays, one CCD for the visible range, and one InGaAs infrared array, simultaneously available at the sensor output channel of the home made instrument. This microscope has been developed for biomedical analysis of human skin and other similar applications. Results are shown illustrating the technical performances of the instrument and the capability in extracting information about the composition and the structure of different parts or compartments in biological samples as well as in solid statematter. A complete spectroscopic fingerprinting of samples at microscopic level is shown possible by using statistical analysis on raw data or analytical reflectance models based on Abelés matrix transfer methods. PMID:24233077

Producing CCD imaging sensor with flashed backside metal film

NASA Technical Reports Server (NTRS)

Janesick, James R. (Inventor)

1988-01-01

A backside illuminated CCD imaging sensor for reading out image charges from wells of the array of pixels is significantly improved for blue, UV, far UV and low energy x-ray wavelengths (1-5000.ANG.) by so overthinning the backside as to place the depletion edge at the surface and depositing a thin transparent metal film of about 10.ANG. on a native-quality oxide film of less than about 30.ANG. grown on the thinned backside. The metal is selected to have a higher work function than that of the semiconductor to so bend the energy bands (at the interface of the semiconductor material and the oxide film) as to eliminate wells that would otherwise trap minority carriers. A bias voltage may be applied to extend the frontside depletion edge to the interface of the semiconductor material with the oxide film in the event there is not sufficient thinning. This metal film (flash gate), which improves and stabilizes the quantum efficiency of a CCD imaging sensor, will also improve the QE of any p-n junction photodetector.

CCD imaging sensor with flashed backside metal film

NASA Technical Reports Server (NTRS)

Janesick, James R. (Inventor)

1991-01-01

A backside illuminated CCD imaging sensor for reading out image charges from wells of the array of pixels is significantly improved for blue, UV, far UV and low energy x-ray wavelengths (1-5000.ANG.) by so overthinning the backside as to place the depletion edge at the surface and depositing a thin transparent metal film of about 10.ANG. on a native-quality oxide film of less than about 30.ANG. grown on the thinned backside. The metal is selected to have a higher work function than that of the semiconductor to so bend the energy bands (at the interface of the semiconductor material and the oxide film) as to eliminate wells that would otherwise trap minority carriers. A bias voltage may be applied to extend the frontside depletion edge to the interface of the semiconductor material with the oxide film in the event there is not sufficient thinning. This metal film (flash gate), which improves and stabilizes the quantum efficiency of a CCD imaging sensor, will also improve the QE of any p-n junction photodetector.

An evaluation of an ICCD imager of dynamic range expansion technique and application of insitu procedures for life-time extension

NASA Technical Reports Server (NTRS)

Currie, D. G.

1982-01-01

Research toward practical implementation of the Intensified Charge Coupled Device (ICCD) as a photon-counting array detector for astronomy is reported. The first area of concentration was to determine the rate and extent of the lifetime limiting damage to the CCD caused by the impact of high energy electrons, and to find whether various methods of annealing the damage were productive. The second effort was to determine the performance of the ICCD in a photon-counting mode to produce extended dynamic range measurements. There are two main effects that appear as the practical results of the electron damage to the CCD. One is an increase in the leakage current, i.e., the normal thermal generation of charge carriers in the silicon that provides a background dark signal that adds to the light produced image. In an undamaged CCD, the leakage current is usually fairly uniform across the photosensitive area of the silicon chip, with the exception of various bright pixels which have an anomalous leakage current well above the overall level.

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.

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.

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

Particle displacement tracking applied to air flows

NASA Technical Reports Server (NTRS)

Wernet, Mark P.

1991-01-01

Electronic Particle Image Velocimeter (PIV) techniques offer many advantages over conventional photographic PIV methods such as fast turn around times and simplified data reduction. A new all electronic PIV technique was developed which can measure high speed gas velocities. The Particle Displacement Tracking (PDT) technique employs a single cw laser, small seed particles (1 micron), and a single intensified, gated CCD array frame camera to provide a simple and fast method of obtaining two-dimensional velocity vector maps with unambiguous direction determination. Use of a single CCD camera eliminates registration difficulties encountered when multiple cameras are used to obtain velocity magnitude and direction information. An 80386 PC equipped with a large memory buffer frame-grabber board provides all of the data acquisition and data reduction operations. No array processors of other numerical processing hardware are required. Full video resolution (640x480 pixel) is maintained in the acquired images, providing high resolution video frames of the recorded particle images. The time between data acquisition to display of the velocity vector map is less than 40 sec. The new electronic PDT technique is demonstrated on an air nozzle flow with velocities less than 150 m/s.

Design of a Day/Night Star Camera System

NASA Technical Reports Server (NTRS)

Alexander, Cheryl; Swift, Wesley; Ghosh, Kajal; Ramsey, Brian

1999-01-01

This paper describes the design of a camera system capable of acquiring stars during both the day and night cycles of a high altitude balloon flight (35-42 km). The camera system will be filtered to operate in the R band (590-810 nm). Simulations have been run using MODTRAN atmospheric code to determine the worse case sky brightness at 35 km. With a daytime sky brightness of 2(exp -05) W/sq cm/str/um in the R band, the sensitivity of the camera system will allow acquisition of at least 1-2 stars/sq degree at star magnitude limits of 8.25-9.00. The system will have an F2.8, 64.3 mm diameter lens and a 1340X1037 CCD array digitized to 12 bits. The CCD array is comprised of 6.8 X 6.8 micron pixels with a well depth of 45,000 electrons and a quantum efficiency of 0.525 at 700 nm. The camera's field of view will be 6.33 sq degree and provide attitude knowledge to 8 arcsec or better. A test flight of the system is scheduled for fall 1999.

Astigmatism correction of a non-imaging double spectrometer fitted with a 2D array detector

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

Yaney, P.P.; Ernst, S.L.; Blackshire, J.

1992-12-01

A SPEX 1401 double spectrometer was adapted for a liquid nitrogen cooled CCD detector to permit both spectral and spatial analysis of ceramic specimens in a laser Raman microprobe system. The exit image of the spectrometer suffers from astigmatism due to off-axis spherical mirrors. A cylindrical lens was added before the CCD to correct for the astigmatism. The spectrometer and several lenses were modeled using an optical ray tracing program to characterize the astigmatism and to optimize the locations of the lens and the detector. The astigmatism and the spot pattern sizes determined by the model were in good agreementmore » with he observed performance of the modified spectrometer-detector system. Typical spot patterns fell within the 23 {mu}m square pixel size.« less

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.

A Compact Imaging Detector of Polarization and Spectral Content

NASA Technical Reports Server (NTRS)

Rust, D. M.; Kumar, A.; Thompson, K. E.

1993-01-01

A new type of image detector will simultaneously analyze the polarization of light at all picture elements in a scene. The integrated Dual Imaging Detector (IDID) consists of a polarizing beam splitter bonded to a charge-coupled device (CCD), with signal-analysis circuitry and analog-to-digital converters, all integrated on a silicon chip. The polarizing beam splitter can be either a Ronchi ruling, or an array of cylindrical lenslets, bonded to a birefringent wafer. The wafer, in turn, is bonded to the CCD so that light in the two orthogonal planes of polarization falls on adjacent pairs of pixels. The use of a high-index birefringent material, e.g., rutile, allows the IDID to operate at f-numbers as high as f/3.5. Other aspects of the detector are discussed.

Portal imaging with flat-panel detector and CCD camera

NASA Astrophysics Data System (ADS)

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

1997-07-01

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

Shack-Hartmann Phasing of Segmented Telescopes: Systematic Effects from Lenslet Arrays

NASA Technical Reports Server (NTRS)

Troy, Mitchell; Chanan, Gary; Roberts, Jennifer

2010-01-01

The segments in the Keck telescopes are routinely phased using a Shack-Hartmann wavefront sensor with sub-apertures that span adjacent segments. However, one potential limitation to the absolute accuracy of this technique is that it relies on a lenslet array (or a single lens plus a prism array) to form the subimages. These optics have the potential to introduce wavefront errors and stray reflections at the subaperture level that will bias the phasing measurement. We present laboratory data to quantify this effect, using measured errors from Keck and two other lenslet arrays. In addition, as part of the design of the Thirty Meter Telescope Alignment and Phasing System we present a preliminary investigation of a lenslet-free approach that relies on Fresnel diffraction to form the subimages at the CCD. Such a technique has several advantages, including the elimination of lenslet aberrations.

Direct investigation of collective phenomena in patterned Ising-like arrays using high-resolution Kerr microscopy

NASA Astrophysics Data System (ADS)

Fraleigh, Robert Douglas

Magnetic systems with interacting ferromagnetic single-domain elements are a useful landscape to explore a wide range of fundamental and technological phenomena. In this dissertation, we consider a system of interacting ferromagnetic islands with perpendicular anisotropy. Islands are lithographically-defined to be single-domain and are arranged into large arrays with geometries that are geometrically frustrated and unfrustrated. We explore field-driven local and global magnetic switching behavior using a home-built diffraction-limited magneto-optical Kerr microscope wherein individual islands in each array are isolated, indexed, and tracked in the presence of an applied external field. Global and local switching behavior is directly accessed through analysis island switching fields in the presence of magnetic hysteresis loops. We first explore the considerations regarding lithographic definition of disconnected islands and deposition of Co/Pt multilayers with strong perpendicular anisotropy. The thickness and number of stacked Co/Pt bilayers as well as deposition method significantly affect the strength of perpendicular anisotropy. We find sputter deposition of a 8-stack bilayer of Co0.3 nm=Pt 1 nm optimizes strong perpendicular anisotropy with square hysteresis loops. Our experimental sample contains several sets of ordered arrays with varying geometry and inter-island spacing. Each island is single-domain with length scales amenable to Kerr imaging such that magnetic degrees of freedom are optically accessible. We next discuss the development, calibration, and operation of a home-built magneto-optical Kerr microscope. The Kerr microscope uses a xenon stabilized white light source, Glan-Thompson polarizers, and a 100x oil objective lens to illuminate a sample with linear polarized light. A cooled CCD camera receives the re ected light and transmits it to the computer in a sequence timed with the application of an external magnetic field. We use LabVIEW software to isolate, index, track, and extract intensity information and corresponding switching fields associated with individual islands in each array as a function of a magnetic field. We find the switching field distribution width is well-fit by a simple model comprising the sum of an array-independent contribution (interpreted as disorder-induced), and a term proportional to the maximum field the entire rest of the array could exert on a single island, i.e., in a fully polarized state. This supports the claim that disorder in these arrays is primarily a single-island property.

Resolution of Port/Starboard Ambiguity Using a Linear Array of Triplets and a Twin-Line Planar Array

DTIC Science & Technology

2016-06-01

STARBOARD AMBIGUITY USING A LINEAR ARRAY OF TRIPLETS AND A TWIN- LINE PLANAR ARRAY by Stilson Veras Cardoso June 2016 Thesis Advisor...OF TRIPLETS AND A TWIN-LINE PLANAR ARRAY 5. FUNDING NUMBERS 6. AUTHOR(S) Stilson Veras Cardoso 7. PERFORMING ORGANIZATION NAME(S) AND ADDRESS(ES...A LINEAR ARRAY OF TRIPLETS AND A TWIN-LINE PLANAR ARRAY Stilson Veras Cardoso Civilian, Brazilian Navy B.S., University of Brasília, 1993

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.

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.

Beauty and Astrophysics

NASA Astrophysics Data System (ADS)

Bessell, Michael S.

2000-08-01

Spectacular colour images have been made by combining CCD images in three different passbands using Adobe Photoshop. These beautiful images highlight a variety of astrophysical phenomena and should be a valuable resource for science education and public awareness of science. The wide field images were obtained at the Siding Spring Observatory (SSO) by mounting a Hasselblad or Nikkor telephoto lens in front of a 2K × 2K CCD. Options of more than 30 degrees or 6 degrees square coverage are produced in a single exposure in this way. Narrow band or broad band filters were placed between lens and CCD enabling deep, linear images in a variety of passbands to be obtained. We have mapped the LMC and SMC and are mapping the Galactic Plane for comparison with the Molonglo Radio Survey. Higher resolution images have also been made with the 40 inch telescope of galaxies and star forming regions in the Milky Way.

The development of a multifunction lens test instrument by using computer aided variable test patterns

NASA Astrophysics Data System (ADS)

Chen, Chun-Jen; Wu, Wen-Hong; Huang, Kuo-Cheng

2009-08-01

A multi-function lens test instrument is report in this paper. This system can evaluate the image resolution, image quality, depth of field, image distortion and light intensity distribution of the tested lens by changing the tested patterns. This system consists of a tested lens, a CCD camera, a linear motorized stage, a system fixture, an observer LCD monitor, and a notebook for pattern providing. The LCD monitor displays a serious of specified tested patterns sent by the notebook. Then each displayed pattern goes through the tested lens and images in the CCD camera sensor. Consequently, the system can evaluate the performance of the tested lens by analyzing the image of CCD camera with special designed software. The major advantage of this system is that it can complete whole test quickly without interruption due to part replacement, because the tested patterns are statically displayed on monitor and controlled by the notebook.

Defect detection in slab surface: a novel dual Charge-coupled Device imaging-based fuzzy connectedness strategy.

PubMed

Zhao, Liming; Ouyang, Qi; Chen, Dengfu; Udupa, Jayaram K; Wang, Huiqian; Zeng, Yuebin

2014-11-01

To provide an accurate surface defects inspection system and make the automation of robust image segmentation method a reality in routine production line, a general approach is presented for continuous casting slab (CC-slab) surface defects extraction and delineation. The applicability of the system is not tied to CC-slab exclusively. We combined the line array CCD (Charge-coupled Device) traditional scanning imaging (LS-imaging) and area array CCD laser three-dimensional (3D) scanning imaging (AL-imaging) strategies in designing the system. Its aim is to suppress the respective imaging system's limitations. In the system, the images acquired from the two CCD sensors are carefully aligned in space and in time by maximum mutual information-based full-fledged registration schema. Subsequently, the image information is fused from these two subsystems such as the unbroken 2D information in LS-imaging and 3D depressed information in AL-imaging. Finally, on the basis of the established dual scanning imaging system the region of interest (ROI) localization by seed specification was designed, and the delineation for ROI by iterative relative fuzzy connectedness (IRFC) algorithm was utilized to get a precise inspection result. Our method takes into account the complementary advantages in the two common machine vision (MV) systems and it performs competitively with the state-of-the-art as seen from the comparison of experimental results. For the first time, a joint imaging scanning strategy is proposed for CC-slab surface defect inspection that allows a feasible way of powerful ROI delineation strategies to be applied to the MV inspection field. Multi-ROI delineation by using IRFC in this research field may further improve the results.

X-Ray Spectroscopy of Optically Bright Planets using the Chandra Observatory

NASA Technical Reports Server (NTRS)

Ford, P. G.; Elsner, R. F.

2005-01-01

Since its launch in July 1999, Chandra's Advanced CCD Imaging Spectrometer (ACIS) has observed several planets (Venus, Mars, Jupiter and Saturn) and 6 comets. At 0.5 arc-second spatial resolution, ACIS detects individual x-ray photons with good quantum efficiency (25% at 0.6 KeV) and energy resolution (20% FWHM at 0.6 KeV). However, the ACIS CCDs are also sensitive to optical and near-infrared light, which is absorbed by optical blocking filters (OBFs) that eliminate optical contamination from all but the brightest extended sources, e.g., planets. .Jupiter at opposition subseconds approx.45 arc-seconds (90 CCD pixels.) Since Chandra is incapable of tracking a moving target, the planet takes 10 - 20 kiloseconds to move across the most sensitive ACIS CCD, after which the observatory must be re-pointed. Meanwhile, the OBF covering that CCD adds an opt,ical signal equivalent to approx.110 eV to each pixel that lies within thc outline of the Jovian disk. This has three consequences: (1) the observatory must be pointed away from Jupiter while CCD bias maps are constructed; (2) most x-rays from within the optical image will be misidentified as charged-particle background and ignored; and (3) those x-rays that are reported will bc assigned anomalously high energies. The same also applies to thc other planets, but is less serious since they are either dimmer at optical wavelengths, or they show less apparent motion across the sky, permitting reduced CCD exposure times: the optical contamination from Saturn acids approx.15 eV per pixel, and from Mars and Venus approx.31 eV. After analyzing a series of short .Jupiter observations in December 2000, ACIS parameters were optimized for the February 2003 opposition. CCD bias maps were constructed while Chandra pointed away from Jupiter, and the subsequent observations employed on-board software to ignore any pixel that contained less charge than that expected from optical leakage. In addition, ACIS was commanded to report 5 x 5 arrays of pixel values surrounding each x-ray event, and the outlying values were employed during ground processing to correct for the optical contamination.

Event-Driven Random-Access-Windowing CCD Imaging System

NASA Technical Reports Server (NTRS)

Monacos, Steve; Portillo, Angel; Ortiz, Gerardo; Alexander, James; Lam, Raymond; Liu, William

2004-01-01

A charge-coupled-device (CCD) based high-speed imaging system, called a realtime, event-driven (RARE) camera, is undergoing development. This camera is capable of readout from multiple subwindows [also known as regions of interest (ROIs)] within the CCD field of view. Both the sizes and the locations of the ROIs can be controlled in real time and can be changed at the camera frame rate. The predecessor of this camera was described in High-Frame-Rate CCD Camera Having Subwindow Capability (NPO- 30564) NASA Tech Briefs, Vol. 26, No. 12 (December 2002), page 26. The architecture of the prior camera requires tight coupling between camera control logic and an external host computer that provides commands for camera operation and processes pixels from the camera. This tight coupling limits the attainable frame rate and functionality of the camera. The design of the present camera loosens this coupling to increase the achievable frame rate and functionality. From a host computer perspective, the readout operation in the prior camera was defined on a per-line basis; in this camera, it is defined on a per-ROI basis. In addition, the camera includes internal timing circuitry. This combination of features enables real-time, event-driven operation for adaptive control of the camera. Hence, this camera is well suited for applications requiring autonomous control of multiple ROIs to track multiple targets moving throughout the CCD field of view. Additionally, by eliminating the need for control intervention by the host computer during the pixel readout, the present design reduces ROI-readout times to attain higher frame rates. This camera (see figure) includes an imager card consisting of a commercial CCD imager and two signal-processor chips. The imager card converts transistor/ transistor-logic (TTL)-level signals from a field programmable gate array (FPGA) controller card. These signals are transmitted to the imager card via a low-voltage differential signaling (LVDS) cable assembly. The FPGA controller card is connected to the host computer via a standard peripheral component interface (PCI).

Flat field anomalies in an x-ray charge coupled device camera measured using a Manson x-ray source

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

Haugh, M. J.; Schneider, M. B.

2008-10-15

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 charge coupled device (CCD) chip is an x-ray sensitive silicon sensor, with a large format array (2kx2k), 24 {mu}m square pixels, and 15 {mu}mmore » thick. A multianode Manson x-ray source, operating up to 10 kV and 10 W, 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/{delta}E{approx_equal}10. The x-ray beam intensity was measured using an x-ray photodiode that has an 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 ten energy bands ranging from 930 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

Solar Polarimetry: Proceedings of the National Solar Observatory/ Sacramento Peak Summer Workshop 11th Held in Sunspot, New Mexico on 27-31 August 1990

DTIC Science & Technology

1991-01-01

test at Arosa A,,t rphys- ical Observatory of the ETH Zdrich. Two beam splitters are positioned behind the mcdulat(r parkac’e if three CCD array sensors...data obtained with the Horizontal Telescope of the Arosa Astrophysical Observatory (HAT). The latter consist of simultaneous recordings of the Stokes

Fabricating a hybrid imaging device

NASA Technical Reports Server (NTRS)

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

2003-01-01

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

Optical Readout System for Bi-Material Terahertz Sensors

DTIC Science & Technology

2011-09-01

CCD Charged-Coupled Device DFG Difference-Frequency Generation FOV Field of View FPA Focal Plane Array fps Frames Per Second FTIR Fourier ...techniques in the THz range may be classified as either coherent or incoherent. Basically, coherent detection measures the amplitude and phase of the field...using a lock-in amplifier. In a piezoresistive detector, two electrodes are connected to two deformable temperature–sensitive legs. Monitoring the

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).

Real-time processing for full-range Fourier-domain optical-coherence tomography with zero-filling interpolation using multiple graphic processing units.

PubMed

Watanabe, Yuuki; Maeno, Seiya; Aoshima, Kenji; Hasegawa, Haruyuki; Koseki, Hitoshi

2010-09-01

The real-time display of full-range, 2048?axial pixelx1024?lateral pixel, Fourier-domain optical-coherence tomography (FD-OCT) images is demonstrated. The required speed was achieved by using dual graphic processing units (GPUs) with many stream processors to realize highly parallel processing. We used a zero-filling technique, including a forward Fourier transform, a zero padding to increase the axial data-array size to 8192, an inverse-Fourier transform back to the spectral domain, a linear interpolation from wavelength to wavenumber, a lateral Hilbert transform to obtain the complex spectrum, a Fourier transform to obtain the axial profiles, and a log scaling. The data-transfer time of the frame grabber was 15.73?ms, and the processing time, which includes the data transfer between the GPU memory and the host computer, was 14.75?ms, for a total time shorter than the 36.70?ms frame-interval time using a line-scan CCD camera operated at 27.9?kHz. That is, our OCT system achieved a processed-image display rate of 27.23 frames/s.

Investigation of MHD Instabilities in Jets and Bubbles Using a Compact Coaxial Plasma Gun in a Background Magnetized Plasma

NASA Astrophysics Data System (ADS)

Zhang, Y.; Fisher, D. M.; Wallace, B.; Gilmore, M.; Hsu, S. C.

2016-10-01

A compact coaxial plasma gun is employed for experimental investigation of launching plasma into a lower density background magnetized plasma. Experiments are being conducted in the linear device HelCat at UNM. Four distinct operational regimes with qualitatively different dynamics are identified by fast CCD camera images. For regime I plasma jet formation, a global helical magnetic configuration is determined by a B-dot probe array data. Also the m =1 kink instability is observed and verified. Furthermore, when the jet is propagating into background magnetic field, a longer length and lifetime jet is formed. Axial shear flow caused by the background magnetic tension force contributes to the increased stability of the jet body. In regime II, a spheromak-like plasma bubble formation is identified when the gun plasma is injected into vacuum. In contrast, when the bubble propagates into a background magnetic field, the closed magnetic field configuration does not hold anymore and a lateral side, Reilgh-Taylor instability develops. Detailed experimental data and analysis will be presented for these cases.

Experimental investigation of plasma relaxation using a compact coaxial magnetized plasma gun in a background plasma

NASA Astrophysics Data System (ADS)

Zhang, Yue; Lynn, Alan; Gilmore, Mark; Hsu, Scott; University of New Mexico Collaboration; Los Alamos National Laboratory Collaboration

2013-10-01

A compact coaxial plasma gun is employed for experimental studies of plasma relaxation in a low density background plasma. Experiments are being conducted in the linear HelCat device at UNM. These studies will advance the knowledge of basic plasma physics in the areas of magnetic relaxation and space and astrophysical plasmas, including the evolution of active galactic jets/radio lobes within the intergalactic medium. The gun is powered by a 120pF ignitron-switched capacitor bank which is operated in a range of 5-10 kV and ~100 kA. Multiple diagnostics are employed to investigate plasma relaxation process. Magnetized Argon plasma bubbles with velocities ~1.2Cs and densities ~1020 m-3 have been achieved. Different distinct regimes of operation with qualitatively different dynamics are identified by fast CCD camera images, with the parameter determining the operation regime. Additionally, a B-dot probe array is employed to measure the spatial toroidal and poloidal magnetic flux evolution to identify detached plasma bubble configurations. Experimental data and analysis will be presented.

Space infrared telescope pointing control system. Infrared telescope tracking in the presence of target motion

NASA Technical Reports Server (NTRS)

Powell, J. D.; Schneider, J. B.

1986-01-01

The use of charge-coupled-devices, or CCD's, has been documented by a number of sources as an effective means of providing a measurement of spacecraft attitude with respect to the stars. A method exists of defocussing and interpolation of the resulting shape of a star image over a small subsection of a large CCD array. This yields an increase in the accuracy of the device by better than an order of magnitude over the case when the star image is focussed upon a single CCD pixel. This research examines the effect that image motion has upon the overall precision of this star sensor when applied to an orbiting infrared observatory. While CCD's collect energy within the visible spectrum of light, the targets of scientific interest may well have no appreciable visible emissions. Image motion has the effect of smearing the image of the star in the direction of motion during a particular sampling interval. The presence of image motion is incorporated into a Kalman filter for the system, and it is shown that the addition of a gyro command term is adequate to compensate for the effect of image motion in the measurement. The updated gyro model is included in this analysis, but has natural frequencies faster than the projected star tracker sample rate for dim stars. The system state equations are reduced by modelling gyro drift as a white noise process. There exists a tradeoff in selected star tracker sample time between the CCD, which has improved noise characteristics as sample time increases, and the gyro, which will potentially drift further between long attitude updates. A sample time which minimizes pointing estimation error exists for the random drift gyro model as well as for a random walk gyro model.

Collision management utilizing CCD and remote sensing technology

NASA Technical Reports Server (NTRS)

Mcdaniel, Harvey E., Jr.

1995-01-01

With the threat of damage to aerospace systems (space station, shuttle, hypersonic a/c, solar power satellites, loss of life, etc.) from collision with debris (manmade/artificial), there exists an opportunity for the design of a novel system (collision avoidance) to be incorporated into the overall design. While incorporating techniques from ccd and remote sensing technologies, an integrated system utilized in the infrared/visible spectrum for detection, tracking, localization, and maneuvering from doppler shift measurements is achievable. Other analysis such as impact assessment, station keeping, chemical, and optical tracking/fire control solutions are possible through this system. Utilizing modified field programmable gated arrays (software reconfiguring the hardware) the mission and mission effectiveness can be varied. This paper outlines the theoretical operation of a prototype system as it applies to collision avoidance (to be followed up by research).

Colorimetric detection of melamine in milk by using gold nanoparticles-based LSPR via optical fibers

PubMed Central

Chang, Keke; Wang, Shun; Zhang, Hao; Guo, Qingqian; Hu, Xinran; Lin, Zhili; Sun, Haifeng; Jiang, Min

2017-01-01

A biosensing system with optical fibers is proposed for the colorimetric detection of melamine in liquid milk samples by using the localized surface plasmon resonance (LSPR) of unmodified gold nanoparticles (AuNPs). The biosensing system consists of a broadband light source that covers the spectral range from 200 nm to 1700 nm, an optical attenuator, three types of 600 μm premium optical fibers with SMA905 connectors and a miniature spectrometer with a linear charge coupled device (CCD) array. The biosensing system with optical fibers is low-cost, simple and is well-proven for the detection of melamine. Its working principle is based on the color changes of AuNPs solution from wine-red to blue due to the inter-particle coupling effect that causes the shifts of wavelength and absorbance in LSPR band after the to-be-measured melamine samples were added. Under the optimized conditions, the detection response of the LSPR biosensing system was found to be linear in melamine detection in the concentration range from 0μM to 0.9 μM with a correlation coefficient (R2) 0.99 and a detection limit 33 nM. The experimental results obtained from the established LSPR biosensing system in the actual detection of melamine concentration in liquid milk samples show that this technique is highly specific and sensitive and would have a huge application prospects. PMID:28475597

Comparison of divided and full pupil configurations for line-scanning confocal microscopy in human skin and oral mucosa

NASA Astrophysics Data System (ADS)

Larson, Bjorg; Abeytunge, Sanjeewa; Glazowski, Chris; Rajadhyaksha, Milind

2012-02-01

Confocal point-scanning microscopy has been showing promise in the detection, diagnosing and mapping of skin lesions in clinical settings. The noninvasive technique allows provides optical sectioning and cellular resolution for in vivo diagnosis of melanoma and basal cell carcinoma and pre-operative and intra-operative mapping of margins. The imaging has also enabled more accurate "guided" biopsies while minimizing the otherwise large number of "blind" biopsies. Despite these translational advances, however, point-scanning technology remains relatively complex and expensive. Line-scanning technology may offer an alternative approach to accelerate translation to the clinic. Line-scanning, using fewer optical components, inexpensive linear-array detectors and custom electronics, may enable smaller, simpler and lower-cost confocal microscopes. A line is formed using a cylindrical lens and scanned through the back focal plane of the objective with a galvanometric scanner. A linear CCD is used for detection. Two pupil configurations were compared for performance in imaging human tissue. In the full-pupil configuration, illumination and detection is made through the full objective pupil. In the divided pupil approach, half the pupil is illuminated and the other half is used for detection. The divided pupil configuration loses spatial and axial resolution due to a diminished NA, but the sectioning capability and rejection of background is improved. Imaging in skin and oral mucosa illustrate the performance of the two configurations.

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.

SONTRAC: A High Efficiency Solar Neutron Telescope

NASA Astrophysics Data System (ADS)

Wunderer, C. B.; Macri, J.; McConnell, M. L.; Ryan, J. M.; Baltgalvis, J.; Holslin, D.; Polichar, A.; Jenkins, T.

1997-05-01

Solar flare neutron emission between 20 and 100 MeV comes from a portion of the energetic proton spectrum that is poorly sampled by both nuclear-line and pion- decay gamma rays. SONTRAC is a new generation solar neutron telescope/spectrometer consisting of densely packed, alternating orthogonal layers of scintillating plastic fibers. The fibers in both dimensions are viewed by image intensifiers and CCD cameras. Incident neutrons scatter off hydrogen in the plastic scintillator. The resulting ionizing proton tracks can be reconstructed in three dimensions using the two planar CCD track images. Two neutron-proton scatters provide sufficient information to reconstruct the energy and direction of the incident neutron. Photomultiplier tubes view the other sides of the fiber scintillator array. The signals from the PMTs are used to give an additional measure of the proton energies and to provide a trigger for the CCD cameras. Recent technological advances have allowed us to construct an affordable working prototype instrument that consists of all the essential technical elements mentioned above. We will present images of tracks produced by minimum ionizing muons and energetic neutrons. We will also present efficiency estimates for SONTRAC's ability to detect and measure gamma rays above 10 MeV.

Undersampled digital holographic interferometry

NASA Astrophysics Data System (ADS)

Halaq, H.; Demoli, N.; Sović, I.; Šariri, K.; Torzynski, M.; Vukičević, D.

2008-04-01

In digital holography, primary holographic fringes are recorded using a matricial CCD sensor. Because of the low spatial resolution of currently available CCD arrays, the angle between the reference and object beams must be limited to a few degrees. Namely, due to the digitization involved, the Shannon's criterion imposes that the Nyquist sampling frequency be at least twice the highest signal frequency. This means that, in the case of the recording of an interference fringe pattern by a CCD sensor, the inter-fringe distance must be larger than twice the pixel period. This in turn limits the angle between the object and the reference beams. If this angle, in a practical holographic interferometry measuring setup, cannot be limited to the required value, aliasing will occur in the reconstructed image. In this work, we demonstrate that the low spatial frequency metrology data could nevertheless be efficiently extracted by careful choice of twofold, and even threefold, undersampling of the object field. By combining the time-averaged recording with subtraction digital holography method, we present results for a loudspeaker membrane interferometric study obtained under strong aliasing conditions. High-contrast fringes, as a consequence of the vibration modes of the membrane, are obtained.

Flash Photolysis Experiment of o-Methyl Red as a Function of pH: A Low-Cost Experiment for the Undergraduate Physical Chemistry Lab

ERIC Educational Resources Information Center

Larsen, Molly C.; Perkins, Russell J.

2016-01-01

A low-cost, time-resolved spectroscopy experiment appropriate for third year physical chemistry students is presented. Students excite o-methyl red in basic solutions with a laser pointer and use a modular spectrometer with a CCD array detector to monitor the transient spectra as the higher-energy cis conformer of the molecule converts back to the…

Fabricating a hybrid imaging device having non-destructive sense nodes

NASA Technical Reports Server (NTRS)

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

2001-01-01

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

Spectral domain optical coherence tomography with dual-balanced detection

NASA Astrophysics Data System (ADS)

Bo, En; Liu, Xinyu; Chen, Si; Luo, Yuemei; Wang, Nanshuo; Wang, Xianghong; Liu, Linbo

2016-03-01

We developed a spectral domain optical coherence tomography (SD-OCT) system employing dual-balanced detection (DBD) for direct current term suppression and SNR enhancement, especially for auto-autocorrelation artifacts reduction. The DBD was achieved by using a beam splitter to building a free-space Michelson interferometer, which generated two interferometric spectra with a phase difference of π. These two phase-opposed spectra were guided to the spectrometer through two single mode fibers of the 8 fiber v-groove array and acquired by ultizing the upper two lines of a three-line CCD camera. We rotated this fiber v-groove array by 1.35 degrees to focus two spectra onto the first and second line of the CCD camera. Two spectra were aligned by optimum spectrum matching algorithm. By subtracting one spectrum from the other, this dual-balanced detection system achieved a direct current term suppression of ~30 dB, SNR enhancement of ~3 dB, and auto-autocorrelation artifacts reduction of ~10 dB experimentally. Finally we respectively validated the feasibility and performance of dual-balanced detection by imaging a glass plate and swine corneal tissue ex vivo. The quality of images obtained using dual-balanced detection was significantly improved with regard to the conventional single-detection (SD) images.

NICOLAU: compact unit for photometric characterization of automotive lighting from near-field measurements

NASA Astrophysics Data System (ADS)

Royo, Santiago; Arranz, Maria J.; Arasa, Josep; Cattoen, Michel; Bosch, Thierry

2005-02-01

The present works depicts a measurement technique intended to enhance the characterization procedures of the photometric emissions of automotive headlamps, with potential applications to any light source emission, either automotive or non-automotive. A CCD array with a precisely characterized optical system is used for sampling the luminance field of the headlamp just a few centimetres in front of it, by combining deflectometric techniques (yielding the direction of the light beams) and photometric techniques (yielding the energy travelling in each direction). The CCD array scans the measurement plane using a self-developed mechanical unit and electronics, and then image-processing techniques are used for obtaining the photometric behaviour of the headlamp in any given plane, in particular in the plane and positions required by current normative, but also on the road, on traffic signs, etc. An overview of the construction of the system, of the considered principle of measurement, and of the main calibrations performed on the unit is presented. First results concerning relative measurements are presented compared both to reference data from a photometric tunnel and from a plane placed 5m away from the source. Preliminary results for the absolute photometric calibration of the system are also presented for different illumination beams of different headlamps (driving and passing beam).

Breadboard linear array scan imager using LSI solid-state technology

NASA Technical Reports Server (NTRS)

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

1976-01-01

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

System and method for 100% moisture and basis weight measurement of moving paper

DOEpatents

Hernandez, Jose E.; Koo, Jackson C.

2002-01-01

A system for characterizing a set of properties for a moving substance are disclosed. The system includes: a first near-infrared linear array; a second near-infrared linear array; a first filter transparent to a first absorption wavelength emitted by the moving substance and juxtaposed between the substance and the first array; a second filter blocking the first absorption wavelength emitted by the moving substance and juxtaposed between the substance and the second array; and a computational device for characterizing data from the arrays into information on a property of the substance. The method includes the steps of: filtering out a first absorption wavelength emitted by a substance; monitoring the first absorption wavelength with a first near-infrared linear array; blocking the first wavelength from reaching a second near-infrared linear array; and characterizing data from the arrays into information on a property of the substance.

Optical responses evoked by white matter stimulation in rat visual cortical slices and their relation to neural activities.

PubMed

Tanifuji, M; Yamanaka, A; Sunaba, R; Terakawa, S; Toyama, K

1996-10-28

To characterize optical responses (ORs) evoked by white matter (WM) stimulation in slices of rat visual cortex (VC) stained with voltage sensitive dyes, time course of ORs in each layer was investigated by recording ORs with a linearly aligned photodiode array, and the spatial patterns of the ORs at specified time after stimulation were investigated by a CCD camera in combination with stroboscopic illumination. The ORs recorded by the photodiode array were an increase in absorption at 700 nm and a decrease in the wavelength below 650 nm, suggesting that the ORs were dye related. The ORs were compared with field potentials (FPs) to clarify that neural events were represented by the ORs, and in support of this view, we found that the first order spatial differentials of ORs and that of FPs were in good agreement. We further compared ORs with intracellular responses, and found that the ORs mainly represent postsynaptic potentials (PSPs) of VC neurons except for the deeper part of layer VI, where a component representing action potentials in fibers stimulated directly was observed. The time-lapse imaging of ORs showed that excitation first propagated vertically up to layer I and subsequently in the horizontal direction along layers II-III and V-VI as in previous investigations. Spatio-temporal patterns of ORs under blockade of synaptic transmission were also investigated to reveal activity of fibers evoked by WM stimulation which produced such patterns of propagation.

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, the window would be a slit, the CCD would contain a one-dimensional array of pixels, and the objective lens would be moved along an axis perpendicular to the slit to spatially scan the image of the specimen in pushbroom fashion. The image built up by scanning in this case would be an ordinary (non-spectral) image. In another version, the optics of which are depicted in the lower part of the figure, the spatial window would be a slit, the CCD would contain a two-dimensional array of pixels, the slit image would be refocused onto the CCD by a relay-lens pair consisting of a collimating and a focusing lens, and a prism-gratingprism optical spectrometer would be placed between the collimating and focusing lenses. Consequently, the image on the CCD would be spatially resolved along the slit axis and spectrally resolved along the axis perpendicular to the slit. As in the first-mentioned version, the objective lens would be moved along an axis perpendicular to the slit to spatially scan the image of the specimen in pushbroom fashion.

Lasercom system architecture with reduced complexity

NASA Technical Reports Server (NTRS)

Lesh, James R. (Inventor); Chen, Chien-Chung (Inventor); Ansari, Homayoon (Inventor)

1994-01-01

Spatial acquisition and precision beam pointing functions are critical to spaceborne laser communication systems. In the present invention, a single high bandwidth CCD detector is used to perform both spatial acquisition and tracking functions. Compared to previous lasercom hardware design, the array tracking concept offers reduced system complexity by reducing the number of optical elements in the design. Specifically, the design requires only one detector and one beam steering mechanism. It also provides the means to optically close the point-ahead control loop. The technology required for high bandwidth array tracking was examined and shown to be consistent with current state of the art. The single detector design can lead to a significantly reduced system complexity and a lower system cost.

LaserCom System Architecture With Reduced Complexity

NASA Technical Reports Server (NTRS)

Lesh, James R. (Inventor); Chen, Chien-Chung (Inventor); Ansari, Homa-Yoon (Inventor)

1996-01-01

Spatial acquisition and precision beam pointing functions are critical to spaceborne laser communication systems. In the present invention a single high bandwidth CCD detector is used to perform both spatial acquisition and tracking functions. Compared to previous lasercom hardware design, the array tracking concept offers reduced system complexity by reducing the number of optical elements in the design. Specifically, the design requires only one detector and one beam steering mechanism. It also provides means to optically close the point-ahead control loop. The technology required for high bandwidth array tracking was examined and shown to be consistent with current state of the art. The single detector design can lead to a significantly reduced system complexity and a lower system cost.

Analysis of mutations in oral poliovirus vaccine by hybridization with generic oligonucleotide microchips.

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

Proudnikov, D.; Kirillov, E.; Chumakov, K.

2000-01-01

This paper describes use of a new technology of hybridization with a micro-array of immobilized oligonucleotides for detection and quantification of neurovirulent mutants in Oral Poliovirus Vaccine (OPV). We used a micro-array consisting of three-dimensional gel-elements containing all possible hexamers (total of 4096 probes). Hybridization of fluorescently labelled viral cDNA samples with such microchips resulted in a pattern of spots that was registered and quantified by a computer-linked CCD camera, so that the sequence of the original cDNA could be deduced. The method could reliably identify single point mutations, since each of them affected fluorescence intensity of 12 micro-array elements.more » Micro-array hybridization of DNA mixtures with varying contents of point mutants demonstrated that the method can detect as little as 10% of revertants in a population of vaccine virus. This new technology should be useful for quality control of live viral vaccines, as well as for other applications requiring identification and quantification of point mutations.« less

Miniaturized high throughput detection system for capillary array electrophoresis on chip with integrated light emitting diode array as addressed ring-shaped light source.

PubMed

Ren, Kangning; Liang, Qionglin; Mu, Xuan; Luo, Guoan; Wang, Yiming

2009-03-07

A novel miniaturized, portable fluorescence detection system for capillary array electrophoresis (CAE) on a microfluidic chip was developed, consisting of a scanning light-emitting diode (LED) light source and a single point photoelectric sensor. Without charge coupled detector (CCD), lens, fibers and moving parts, the system was extremely simplified. Pulsed driving of the LED significantly increased the sensitivity, and greatly reduced the power consumption and photobleaching effect. The highly integrated system was robust and easy to use. All the advantages realized the concept of a portable micro-total analysis system (micro-TAS), which could work on a single universal serial bus (USB) port. Compared with traditional CAE detecting systems, the current system could scan the radial capillary array with high scanning rate. An 8-channel CAE of fluorescein isothiocyanate (FITC) labeled arginine (Arg) on chip was demonstrated with this system, resulting in a limit of detection (LOD) of 640 amol.

Digital Mammography with a Mosaic of CCD-Arrays

NASA Technical Reports Server (NTRS)

Jalink, Antony, Jr. (Inventor); McAdoo, James A. (Inventor)

1996-01-01

The present invention relates generally to a mammography device and method and more particularly to a novel digital mammography device and method to detect microcalcifications of precancerous tissue. A digital mammography device uses a mosaic of electronic digital imaging arrays to scan an x-ray image. The mosaic of arrays is repositioned several times to expose different portions of the image, until the entire image is scanned. The data generated by the arrays during each exposure is stored in a computer. After the final exposure, the computer combines data of the several partial images to produce a composite of the original x-ray image. An aperture plate is used to reduce scatter and the overall exposure of the patient to x-rays. The novelty of this invention is that it provides a digital mammography device with large field coverage, high spatial resolution, scatter rejection, excellent contrast characteristics and lesion detectability under clinical conditions. This device also shields the patient from excessive radiation, can detect extremely small calcifications and allows manipulation and storage of the image.

Time delay and integration array (TDI) using charge transfer device technology. Phase 2, volume 1: Technical

NASA Technical Reports Server (NTRS)

1977-01-01

The 20x9 TDI array was developed to meet the LANDSAT Thematic Mapper Requirements. This array is based upon a self-aligned, transparent gate, buried channel process. The process features: (1) buried channel, four phase, overlapping gate CCD's for high transfer efficiency without fat zero; (2) self-aligned transistors to minimize clock feedthrough and parasitic capacitance; and (3) transparent tin oxide electrode for high quantum efficiency with front surface irradiation. The requirements placed on the array and the performance achieved are summarized. This data is the result of flat field measurements only, no imaging or dynamic target measurements were made during this program. Measurements were performed with two different test stands. The bench test equipment fabricated for this program operated at the 8 micro sec line time and employed simple sampling of the gated MOSFET output video signal. The second stand employed Correlated Doubled Sampling (CDS) and operated at 79.2 micro sec line time.

VizieR Online Data Catalog: Proper motions and photometry of stars in NGC 3201 (Sariya+, 2017)

NASA Astrophysics Data System (ADS)

Sariya, D. P.; Jiang, I.-G.; Yadav, R. K. S.

2017-07-01

To determine the PMs of the stars in this work, we used archive images (http://archive.eso.org/eso/esoarchivemain.html) from observations made with the 2.2m ESO/MPI telescope at La Silla, Chile. This telescope contains a mosaic camera called the Wide-Field Imager (WFI), consisting of 4*2 (i.e., 8 CCD chips). Since each CCD has an array of 2048*4096 pixels, WFI ultimately produces images with a 34*33arcmin2 field of view. The observational run of the first epoch contains two images in B,V and I bands, each with 240s exposure time observed on 1999 December 05. In the second epoch, we have 35 images with 40s exposure time each in V filter observed during the period of 2014 April 02-05. Thus the epoch gap between the data is ~14.3 years. (2 data files).

Ultrafast Imaging using Spectral Resonance Modulation

NASA Astrophysics Data System (ADS)

Huang, Eric; Ma, Qian; Liu, Zhaowei

2016-04-01

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

Rocket and laboratory studies in astronomy

NASA Technical Reports Server (NTRS)

Feldman, P. D.

1993-01-01

This report covers the period from September 1, 1992 to August 31, 1993. During the reporting period we launched the Faint Object Telescope to measure absolute fluxes of two hot dwarf stars in the spectral range below 1200 A. Although all systems worked normally, a higher than anticipated pressure in the detector led to ion-feedback that masked the useable data from the source. We have identified the source of the problem and are preparing for a reflight in the Fall of 1993. Our laboratory program for the evaluation of the ultraviolet performance of charge-coupled-detector (CCD) arrays continued with the aim of including a UV-sensitive CCD in a payload to be flown in 1994, and we have begun the assembly of this payload. Work has continued on the analysis of data from previous rocket experiments and from the UVX experiment which flew on STS-61C in January 1986.

Method for Accurately Calibrating a Spectrometer Using Broadband Light

NASA Technical Reports Server (NTRS)

Simmons, Stephen; Youngquist, Robert

2011-01-01

A novel method has been developed for performing very fine calibration of a spectrometer. This process is particularly useful for modern miniature charge-coupled device (CCD) spectrometers where a typical factory wavelength calibration has been performed and a finer, more accurate calibration is desired. Typically, the factory calibration is done with a spectral line source that generates light at known wavelengths, allowing specific pixels in the CCD array to be assigned wavelength values. This method is good to about 1 nm across the spectrometer s wavelength range. This new method appears to be accurate to about 0.1 nm, a factor of ten improvement. White light is passed through an unbalanced Michelson interferometer, producing an optical signal with significant spectral variation. A simple theory can be developed to describe this spectral pattern, so by comparing the actual spectrometer output against this predicted pattern, errors in the wavelength assignment made by the spectrometer can be determined.

Multistatic Array Sampling Scheme for Fast Near-Field Image Reconstruction

DTIC Science & Technology

2016-01-01

reconstruction. The array topology samples the scene on a regular grid of phase centers, using a tiling of Boundary Arrays (BAs). Following a simple correction...hardware. Fig. 1 depicts the multistatic array topology. As seen, the topology is a tiled arrangement of Boundary Arrays (BAs). The BA is a well-known...sparse array layout comprised of two linear transmit arrays, and two linear receive arrays [6]. A slightly different tiled arrangement of BAs was used

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 current. We have also observed the effects of clocking waveform shapes on spurious charge generation. While these new CCDs promise to be a major advance in CD technology, they too have limitations such as charge spreading and cosmic-ray effects. These limitations have been characterized and are presented. Examples of astronomical observations obtained with the backside CCD on the 1-meter reflector at Lick Observatory are presented.

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 monochromatic x-rays above and below the K-edge of selenium. The MTF is poorer above the K-edge by an amount consistent with theoretical expectations.

Linear dependence between the wavefront gradient and the masked intensity for the point source with a CCD sensor

NASA Astrophysics Data System (ADS)

Yang, Huizhen; Ma, Liang; Wang, Bin

2018-01-01

In contrast to the conventional adaptive optics (AO) system, the wavefront sensorless (WFSless) AO system doesn't need a WFS to measure the wavefront aberrations. It is simpler than the conventional AO in system architecture and can be applied to the complex conditions. The model-based WFSless system has a great potential in real-time correction applications because of its fast convergence. The control algorithm of the model-based WFSless system is based on an important theory result that is the linear relation between the Mean-Square Gradient (MSG) magnitude of the wavefront aberration and the second moment of the masked intensity distribution in the focal plane (also called as Masked Detector Signal-MDS). The linear dependence between MSG and MDS for the point source imaging with a CCD sensor will be discussed from theory and simulation in this paper. The theory relationship between MSG and MDS is given based on our previous work. To verify the linear relation for the point source, we set up an imaging model under atmospheric turbulence. Additionally, the value of MDS will be deviate from that of theory because of the noise of detector and further the deviation will affect the correction effect. The theory results under noise will be obtained through theoretical derivation and then the linear relation between MDS and MDS under noise will be discussed through the imaging model. Results show the linear relation between MDS and MDS under noise is also maintained well, which provides a theoretical support to applications of the model-based WFSless system.

Method and apparatus for acquisition and tracking of light sources in a transient event rich environment

NASA Technical Reports Server (NTRS)

Bolin, Kenneth (Inventor); Flynn, David (Inventor); Fowski, Walter (Inventor); Miklus, Kenneth (Inventor); Kissh, Frank (Inventor); Abreu, Rene (Inventor)

1993-01-01

A method and apparatus for tracking a light source in a transient event rich environment locks on to a light source incident on a field-of-view 1 of a charge-coupled-device (CCD) array 6, validates the permanence of said light source and transmits data relating to the brilliance and location of said light source if said light source is determined to be permanent.

A Wide Dynamic Range Tapped Linear Array Image Sensor

NASA Astrophysics Data System (ADS)

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

1988-08-01

Detectors for acousto-optic signal processing applications require fast transient response as well as wide dynamic range. There are two major choices of detectors: conductive or integration mode. Conductive mode detectors have an initial transient period before they reach then' i equilibrium state. The duration of 1 his period is dependent on light level as well as detector capacitance. At low light levels a conductive mode detector is very slow; response time is typically on the order of milliseconds. Generally. to obtain fast transient response an integrating mode detector is preferred. With integrating mode detectors. the dynamic range is determined by the charge storage capability of the tran-sport shift registers and the noise level of the image sensor. The conventional net hod used to improve dynamic range is to increase the shift register charge storage capability. To achieve a dynamic range of fifty thousand assuming two hundred noise equivalent electrons, a charge storage capability of ten million electrons would be required. In order to accommodate this amount of charge. unrealistic shift registers widths would be required. Therefore, with an integrating mode detector it is difficult to achieve a dynamic range of over four orders of magnitude of input light intensity. Another alternative is to solve the problem at the photodetector aml not the shift, register. DALSA's wide dynamic range detector utilizes an optimized, ion implant doped, profiled MOSFET photodetector specifically designed for wide dynamic range. When this new detector operates at high speed and at low light levels the photons are collected and stored in an integrating fashion. However. at bright light levels where transient periods are short, the detector switches into a conductive mode. The light intensity is logarithmically compressed into small charge packets, easily carried by the CCD shift register. As a result of the logarithmic conversion, dynamic ranges of over six orders of magnitide are obtained. To achieve the short integration times necessary in acousto-optic applications. t he wide dynamic range detector has been implemented into a tapped array architecture with eight outputs and 256 photoelements. Operation of each 01)1,1)111 at 16 MHz yields detector integration times of 2 micro-seconds. Buried channel two phase CCD shift register technology is utilized to minimize image sensor noise improve video output rates and increase ease of operation.

The CAOS camera platform: ushering in a paradigm change in extreme dynamic range imager design

NASA Astrophysics Data System (ADS)

Riza, Nabeel A.

2017-02-01

Multi-pixel imaging devices such as CCD, CMOS and Focal Plane Array (FPA) photo-sensors dominate the imaging world. These Photo-Detector Array (PDA) devices certainly have their merits including increasingly high pixel counts and shrinking pixel sizes, nevertheless, they are also being hampered by limitations in instantaneous dynamic range, inter-pixel crosstalk, quantum full well capacity, signal-to-noise ratio, sensitivity, spectral flexibility, and in some cases, imager response time. Recently invented is the Coded Access Optical Sensor (CAOS) Camera platform that works in unison with current Photo-Detector Array (PDA) technology to counter fundamental limitations of PDA-based imagers while providing high enough imaging spatial resolution and pixel counts. Using for example the Texas Instruments (TI) Digital Micromirror Device (DMD) to engineer the CAOS camera platform, ushered in is a paradigm change in advanced imager design, particularly for extreme dynamic range applications.

Conformal array design on arbitrary polygon surface with transformation optics

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

Deng, Li, E-mail: dengl@bupt.edu.cn; Hong, Weijun, E-mail: hongwj@bupt.edu.cn; Zhu, Jianfeng

2016-06-15

A transformation-optics based method to design a conformal antenna array on an arbitrary polygon surface is proposed and demonstrated in this paper. This conformal antenna array can be adjusted to behave equivalently as a uniformly spaced linear array by applying an appropriate transformation medium. An typical example of general arbitrary polygon conformal arrays, not limited to circular array, is presented, verifying the proposed approach. In summary, the novel arbitrary polygon surface conformal array can be utilized in array synthesis and beam-forming, maintaining all benefits of linear array.

Restoring Low Sidelobe Antenna Patterns with Failed Elements in a Phased Array Antenna

DTIC Science & Technology

2016-02-01

optimum low sidelobes are demonstrated in several examples. Index Terms — Array signal processing, beams, linear algebra , phased arrays, shaped...represented by a linear combination of low sidelobe beamformers with no failed elements, ’s, in a neighborhood around under the constraint that the linear ...would expect that linear combinations of them in a neighborhood around would also have low sidelobes. The algorithms in this paper exploit this

Focal plane alignment and detector characterization for the Subaru prime focus spectrograph

NASA Astrophysics Data System (ADS)

Hart, Murdock; Barkhouser, Robert H.; Carr, Michael; Golebiowski, Mirek; Gunn, James E.; Hope, Stephen C.; Smee, Stephen A.

2014-07-01

We describe the infrastructure being developed to align and characterize the detectors for the Subaru Measure- ment of Images and Redshifts (SuMIRe) Prime Focus Spectrograph (PFS). PFS will employ four three-channel spectrographs with an operating wavelength range of 3800 °A to 12600 °A. Each spectrograph will be comprised of two visible channels and one near infrared (NIR) channel, where each channel will use a separate Schmidt camera to image the captured spectra onto their respective detectors. In the visible channels, Hamamatsu 2k × 4k CCDs will be mounted in pairs to create a single 4k × 4k detector, while the NIR channel will use a single Teledyne 4k × 4k H4RG HgCdTe device. The fast f/1.1 optics of the Schmidt cameras will give a shallow depth of focus necessitating an optimization of the focal plane array flatness. The minimum departure from flatness of the focal plane array for the visible channels is set the by the CCD flatness, typically 10 μm peak-to-valley. We will adjust the coplanarity for a pair of CCDs such that the flatness of the array is consistent with the flatness of the detectors themselves. To achieve this we will use an optical non-contact measurement system to measure surface flatness and coplanarity at both ambient and operating temperatures, and use shims to adjust the coplanarity of the CCDs. We will characterize the performance of the detectors for PFS consistent with the scientific goals for the project. To this end we will measure the gain, linearity, full well, quantum efficiency (QE), charge diffusion, charge transfer inefficiency (CTI), and noise properties of these devices. We also desire to better understand the non-linearity of the photon transfer curve for the CCDs, and the charge persistence/reciprocity problems of the HgCdTe devices. To enable the metrology and characterization of these detectors we are building two test cryostats nearly identical in design. The first test cryostat will primarily be used for the coplanarity measurements and sub- pixel illumination testing, and the second will be dedicated to performance characterization requiring at field illumination. In this paper we will describe the design of the test cryostats. We will also describe the system we have built for measuring focal plane array flatness, and examine the precision and error with which it operates. Finally we will detail the methods by which we plan to characterize the performance of the detectors for PFS, and provide preliminary results.

Comparing simulations and test data of a radiation damaged charge-coupled device for the Euclid mission

NASA Astrophysics Data System (ADS)

Skottfelt, Jesper; Hall, David J.; Gow, Jason P. D.; Murray, Neil J.; Holland, Andrew D.; Prod'homme, Thibaut

2017-04-01

The visible imager instrument on board the Euclid mission is a weak-lensing experiment that depends on very precise shape measurements of distant galaxies obtained by a large charge-coupled device (CCD) array. Due to the harsh radiative environment outside the Earth's atmosphere, it is anticipated that the CCDs over the mission lifetime will be degraded to an extent that these measurements will be possible only through the correction of radiation damage effects. We have therefore created a Monte Carlo model that simulates the physical processes taking place when transferring signals through a radiation-damaged CCD. The software is based on Shockley-Read-Hall theory and is made to mimic the physical properties in the CCD as closely as possible. The code runs on a single electrode level and takes the three-dimensional trap position, potential structure of the pixel, and multilevel clocking into account. A key element of the model is that it also takes device specific simulations of electron density as a direct input, thereby avoiding making any analytical assumptions about the size and density of the charge cloud. This paper illustrates how test data and simulated data can be compared in order to further our understanding of the positions and properties of the individual radiation-induced traps.

Feasibility study of hidden flow imaging based on laser speckle technique using multiperspectives contrast images

NASA Astrophysics Data System (ADS)

Abookasis, David; Moshe, Tomer

2014-11-01

This paper demonstrates the insertion of lens array in the front of a CCD camera in a laser speckle imaging (LSI) like-technique to acquire multiple speckle reflectance projections for imaging blood flow in an intact biological tissue. In some of LSI applications, flow imaging is obtained by thinning or removing of the upper tissue layers to access blood vessels. In contrast, with the proposed approach flow imaging can be achieved while the tissue is intact. In the system, each lens from an hexagonal lens array observed the sample from slightly different perspectives and captured with a CCD camera. In the computer, these multiview raw images are converted to speckled contrast maps. Then, a self-deconvolution shift-and-add algorithm is employed for processing yields high contrast flow information. The method is experimentally validated first with a plastic tube filled with scattering liquid running at different controlled flow rates hidden in a biological tissue and then extensively tested for imaging of cerebral blood flow in an intact rodent head experience different conditions. A total of fifteen mice were used in the experiments divided randomly into three groups as follows: Group 1 (n=5) consisted of injured mice experience hypoxic ischemic brain injury monitored for ~40 min. Group 2 (n=5) injured mice experience anoxic brain injury monitored up to 20 min. Group 3 (n=5) experience functional activation monitored up to ~35 min. To increase tissue transparency and the penetration depth of photons through head tissue layers, an optical clearing method was employed. To our knowledge, this work presents for the first time the use of lens array in LSI scheme.

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.

Compression dynamics of quasi-spherical wire arrays with different linear mass profiles

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

Mitrofanov, K. N., E-mail: mitrofan@triniti.ru; Aleksandrov, V. V.; Gritsuk, A. N.

Results of experimental studies of the implosion of quasi-spherical wire (or metalized fiber) arrays are presented. The goal of the experiments was to achieve synchronous three-dimensional compression of the plasma produced in different regions of a quasi-spherical array into its geometrical center. To search for optimal synchronization conditions, quasi-spherical arrays with different initial profiles of the linear mass were used. The following dependences of the linear mass on the poloidal angle were used: m{sub l}(θ) ∝ sin{sup –1}θ and m{sub l}(θ) ∝ sin{sup –2}θ. The compression dynamics of such arrays was compared with that of quasi-spherical arrays without linear massmore » profiling, m{sub l}(θ) = const. To verify the experimental data, the spatiotemporal dynamics of plasma compression in quasi-spherical arrays was studied using various diagnostics. The experiments on three-dimensional implosion of quasi-spherical arrays made it possible to study how the frozen-in magnetic field of the discharge current penetrates into the array. By measuring the magnetic field in the plasma of a quasi-spherical array, information is obtained on the processes of plasma production and formation of plasma flows from the wire/fiber regions with and without an additionally deposited mass. It is found that penetration of the magnetic flux depends on the initial linear mass profile m{sub l}(θ) of the quasi-spherical array. From space-resolved spectral measurements and frame imaging of plasma X-ray emission, information is obtained on the dimensions and shape of the X-ray source formed during the implosion of a quasi-spherical array. The intensity of this source is estimated and compared with that of the Z-pinch formed during the implosion of a cylindrical array.« less

Range imaging laser radar

DOEpatents

Scott, Marion W.

1990-01-01

A laser source is operated continuously and modulated periodically (typicy sinusoidally). A receiver imposes another periodic modulation on the received optical signal, the modulated signal being detected by an array of detectors of the integrating type. Range to the target determined by measuring the phase shift of the intensity modulation on the received optical beam relative to a reference. The receiver comprises a photoemitter for converting the reflected, periodically modulated, return beam to an accordingly modulated electron stream. The electron stream is modulated by a local demodulation signal source and subsequently converted back to a photon stream by a detector. A charge coupled device (CCD) array then averages and samples the photon stream to provide an electrical signal in accordance with the photon stream.

Range imaging laser radar

DOEpatents

Scott, M.W.

1990-06-19

A laser source is operated continuously and modulated periodically (typically sinusoidally). A receiver imposes another periodic modulation on the received optical signal, the modulated signal being detected by an array of detectors of the integrating type. Range to the target determined by measuring the phase shift of the intensity modulation on the received optical beam relative to a reference. The receiver comprises a photoemitter for converting the reflected, periodically modulated, return beam to an accordingly modulated electron stream. The electron stream is modulated by a local demodulation signal source and subsequently converted back to a photon stream by a detector. A charge coupled device (CCD) array then averages and samples the photon stream to provide an electrical signal in accordance with the photon stream. 2 figs.

Principal components analysis of the photoresponse nonuniformity of a matrix detector.

PubMed

Ferrero, Alejandro; Alda, Javier; Campos, Joaquín; López-Alonso, Jose Manuel; Pons, Alicia

2007-01-01

The principal component analysis is used to identify and quantify spatial distributions of relative photoresponse as a function of the exposure time for a visible CCD array. The analysis shows a simple way to define an invariant photoresponse nonuniformity and compare it with the definition of this invariant pattern as the one obtained for long exposure times. Experimental data of radiant exposure from levels of irradiance obtained in a stable and well-controlled environment are used.

JASMINE data analysis

NASA Astrophysics Data System (ADS)

Yamada, Y.; Gouda, N.; Yano, T.; Kobayashi, Y.; Niwa, Y.; Niwa

2008-07-01

Japan Astrometry Satellite Mission for Infrared Exploration (JASMINE) aims to construct a map of the Galactic bulge with a 10 μas accuracy. We use z-band CCD or K-band array detector to avoid dust absorption, and observe about 10 × 20 degrees area around the Galactic bulge region. In this poster, we show the observation strategy, reduction scheme, and error budget. We also show the basic design of the software for the end-to-end simulation of JASMINE, named JASMINE Simulator.

Stray light correction on array spectroradiometers for optical radiation risk assessment in the workplace.

PubMed

Barlier-Salsi, A

2014-12-01

The European directive 2006/25/EC requires the employer to assess and, if necessary, measure the levels of exposure to optical radiation in the workplace. Array spectroradiometers can measure optical radiation from various types of sources; however poor stray light rejection affects their accuracy. A stray light correction matrix, using a tunable laser, was developed at the National Institute of Standards and Technology (NIST). As tunable lasers are very expensive, the purpose of this study was to implement this method using only nine low power lasers; other elements of the correction matrix being completed by interpolation and extrapolation. The correction efficiency was evaluated by comparing CCD spectroradiometers with and without correction and a scanning double monochromator device as reference. Similar to findings recorded by NIST, these experiments show that it is possible to reduce the spectral stray light by one or two orders of magnitude. In terms of workplace risk assessment, this spectral stray light correction method helps determine exposure levels, with an acceptable degree of uncertainty, for the majority of workplace situations. The level of uncertainty depends upon the model of spectroradiometers used; the best results are obtained with CCD detectors having an enhanced spectral sensitivity in the UV range. Thus corrected spectroradiometers require a validation against a scanning double monochromator spectroradiometer before using them for risk assessment in the workplace.

Orbits and emission spectra from the 2014 Camelopardalids

NASA Astrophysics Data System (ADS)

Madiedo, José M.; Trigo-Rodríguez, Josep M.; Zamorano, Jaime; Izquierdo, Jaime; de Miguel, Alejandro Sánchez; Ocaña, Francisco; Ortiz, José L.; Espartero, Francisco; Morillas, Lorenzo G.; Cardeñosa, David; Moreno-Ibáñez, Manuel; Urzáiz, Marta

2014-12-01

We have analysed the meteor activity associated with meteoroids of fresh dust trails of Comet 209P/LINEAR, which produced an outburst of the Camelopardalid meteor shower (IAU code #451, CAM) in 2014 May. With this aim, we have employed an array of high-sensitivity CCD video devices and spectrographs deployed at 10 meteor observing stations in Spain in the framework of the Spanish Meteor Network. Additional meteoroid flux data were obtained by means of two forward-scatter radio systems. The observed peak zenithal hourly rate was much lower than expected, of around 20 meteors h-1. Despite of the small meteor flux in the optical range, we have obtained precise atmospheric trajectory, radiant and orbital information for 11 meteor and fireball events associated with this stream. The ablation behaviour and low tensile strength calculated for these particles reveal that Camelopardalid meteoroids are very fragile, mostly pristine aggregates with strength similar to that of the Orionids and the Leonids. The mineral grains seem to be glued together by a volatile phase. We also present and discuss two unique emission spectra produced by two Camelopardalid bright meteors. These suggest a non-chondritic nature for these particles, which exhibit Fe depletion in their composition.

Design and performance of the SLD vertex detector: a 307 Mpixel tracking system

NASA Astrophysics Data System (ADS)

Abe, K.; Arodzero, A.; Baltay, C.; Brau, J. E.; Breidenbach, M.; Burrows, P. N.; Chou, A. S.; Crawford, G.; Damerell, C. J. S.; Dervan, P. J.; Dong, D. N.; Emmet, W.; English, R. L.; Etzion, E.; Foss, M.; Frey, R.; Haller, G.; Hasuko, K.; Hertzbach, S. S.; Hoeflich, J.; Huffer, M. E.; Jackson, D. J.; Jaros, J. A.; Kelsey, J.; Lee, I.; Lia, V.; Lintern, A. L.; Liu, M. X.; Manly, S. L.; Masuda, H.; McKemey, A. K.; Moore, T. B.; Nichols, A.; Nagamine, T.; Oishi, N.; Osborne, L. S.; Russell, J. J.; Ross, D.; Serbo, V. V.; Sinev, N. B.; Sinnott, J.; Skarpaas, K. Viii; Smy, M. B.; Snyder, J. A.; Strauss, M. G.; Dong, S.; Suekane, F.; Taylor, F. E.; Trandafir, A. I.; Usher, T.; Verdier, R.; Watts, S. J.; Weiss, E. R.; Yashima, J.; Yuta, H.; Zapalac, G.

1997-02-01

This paper describes the design, construction, and initial operation of SLD's upgraded vertex detector which comprises 96 two-dimensional charge-coupled devices (CCDs) with a total of 307 Mpixel. Each pixel functions as an independent particle detecting element, providing space point measurements of charged particle tracks with a typical precision of 4 μm in each co-ordinate. The CCDs are arranged in three concentric cylinders just outside the beam-pipe which surrounds the e +e - collision point of the SLAC Linear Collider (SLC). The detector is a powerful tool for distinguishing displaced vertex tracks, produced by decay in flight of heavy flavour hadrons or tau leptons, from tracks produced at the primary event vertex. The requirements for this detector include a very low mass structure (to minimize multiple scattering) both for mechanical support and to provide signal paths for the CCDs; operation at low temperature with a high degree of mechanical stability; and high speed CCD readout, signal processing, and data sparsification. The lessons learned in achieving these goals should be useful for the construction of large arrays of CCDs or active pixel devices in the future in a number of areas of science and technology.

Linear encoding device

NASA Technical Reports Server (NTRS)

Leviton, Douglas B. (Inventor)

1993-01-01

A Linear Motion Encoding device for measuring the linear motion of a moving object is disclosed in which a light source is mounted on the moving object and a position sensitive detector such as an array photodetector is mounted on a nearby stationary object. The light source emits a light beam directed towards the array photodetector such that a light spot is created on the array. An analog-to-digital converter, connected to the array photodetector is used for reading the position of the spot on the array photodetector. A microprocessor and memory is connected to the analog-to-digital converter to hold and manipulate data provided by the analog-to-digital converter on the position of the spot and to compute the linear displacement of the moving object based upon the data from the analog-to-digital converter.

A Fourier Method for Sidelobe Reduction in Equally Spaced Linear Arrays

NASA Astrophysics Data System (ADS)

Safaai-Jazi, Ahmad; Stutzman, Warren L.

2018-04-01

Uniformly excited, equally spaced linear arrays have a sidelobe level larger than -13.3 dB, which is too high for many applications. This limitation can be remedied by nonuniform excitation of array elements. We present an efficient method for sidelobe reduction in equally spaced linear arrays with low penalty on the directivity. The method involves the following steps: construction of a periodic function containing only the sidelobes of the uniformly excited array, calculation of the Fourier series of this periodic function, subtracting the series from the array factor of the original uniformly excited array after it is truncated, and finally mitigating the truncation effects which yields significant increase in sidelobe level reduction. A sidelobe reduction factor is incorporated into element currents that makes much larger sidelobe reductions possible and also allows varying the sidelobe level incrementally. It is shown that such newly formed arrays can provide sidelobe levels that are at least 22.7 dB below those of the uniformly excited arrays with the same size and number of elements. Analytical expressions for element currents are presented. Radiation characteristics of the sidelobe-reduced arrays introduced here are examined, and numerical results for directivity, sidelobe level, and half-power beam width are presented for example cases. Performance improvements over popular conventional array synthesis methods, such as Chebyshev and linear current tapered arrays, are obtained with the new method.

Advances in diagnostic ultrasonography.

PubMed

Reef, V B

1991-08-01

A wide variety of ultrasonographic equipment currently is available for use in equine practice, but no one machine is optimal for every type of imaging. Image quality is the most important factor in equipment selection once the needs of the practitioner are ascertained. The transducer frequencies available, transducer footprints, depth of field displayed, frame rate, gray scale, simultaneous electrocardiography, Doppler, and functions to modify the image are all important considerations. The ability to make measurements off of videocassette recorder playback and future upgradability should be evaluated. Linear array and sector technology are the backbone of equine ultrasonography today. Linear array technology is most useful for a high-volume broodmare practice, whereas sector technology is ideal for a more general equine practice. The curved or convex linear scanner has more applications than the standard linear array and is equipped with the linear array rectal probe, which provides the equine practitioner with a more versatile unit for equine ultrasonographic evaluations. The annular array and phased array systems have improved image quality, but each has its own limitations. The new sector scanners still provide the most versatile affordable equipment for equine general practice.

Modulation Transfer Function (MTF) measurement techniques for lenses and linear detector arrays

NASA Technical Reports Server (NTRS)

Schnabel, J. J., Jr.; Kaishoven, J. E., Jr.; Tom, D.

1984-01-01

Application is the determination of the Modulation Transfer Function (MTF) for linear detector arrays. A system set up requires knowledge of the MTF of the imaging lens. Procedure for this measurement is described for standard optical lab equipment. Given this information, various possible approaches to MTF measurement for linear arrays is described. The knife edge method is then described in detail.

MSTI-3 sensor package optical design

NASA Astrophysics Data System (ADS)

Horton, Richard F.; Baker, William G.; Griggs, Michael; Nguyen, Van; Baker, H. Vernon

1995-06-01

The MSTI-3 sensor package is a three band imaging telescope for military and dual use sensing missions. The MSTI-3 mission is one of the Air Force Phillips Laboratory's Pegasus launched space missions, a third in the series of state-of-the-art lightweight sensors on low cost satellites. The satellite is planned for launch into a 425 Km orbit in late 1995. The MSTI- 3 satellite is configured with a down looking two axis gimbal and gimbal mirror. The gimbal mirror is an approximately 13 cm by 29 cm mirror which allows a field of regard approximately 100 degrees by 180 degrees. The optical train uses several novel optical features to allow for compactness and light weight. A 105 mm Ritchey Chretien Cassegrain imaging system with a CaF(subscript 2) dome astigmatism corrector is followed by a CaF(subscript 2) beamsplitter cube assembly at the systems first focus. The dichroic beamsplitter cube assembly separates the light into a visible and two IR channels of approximately 2.5 to 3.3, (SWIR), and 3.5 to 4.5, (MWIR), micron wavelength bands. The two IR imaging channels each consist of unity power re-imaging lens cluster, a cooled seven position filter wheel, a cooled Lyot stop and an Amber 256 X 256 InSb array camera. The visible channel uses a unity power re- imaging system prior to a linear variable filter with a Sony CCD array, which allows for a multispectral imaging capability in the 0.5 to 0.8 micron region. The telescope field of view is 1.4 degrees square.

Distance-of-Flight Mass Spectrometry: What, Why, and How?

NASA Astrophysics Data System (ADS)

Dennis, Elise A.; Gundlach-Graham, Alexander W.; Ray, Steven J.; Enke, Christie G.; Hieftje, Gary M.

2016-11-01

Distance-of-flight mass spectrometry (DOFMS) separates ions of different mass-to-charge ( m/ z) by the distance they travel in a given time after acceleration. Like time-of-flight mass spectrometry (TOFMS), separation and mass assignment are based on ion velocity. However, DOFMS is not a variant of TOFMS; different methods of ion focusing and detection are used. In DOFMS, ions are driven orthogonally, at the detection time, onto an array of detectors parallel to the flight path. Through the independent detection of each m/ z, DOFMS can provide both wider dynamic range and increased throughput for m/ z of interest compared with conventional TOFMS. The iso-mass focusing and detection of ions is achieved by constant-momentum acceleration (CMA) and a linear-field ion mirror. Improved energy focus (including turn-around) is achieved in DOFMS, but the initial spatial dispersion of ions remains unchanged upon detection. Therefore, the point-source nature of surface ionization techniques could put them at an advantage for DOFMS. To date, three types of position-sensitive detectors have been used for DOFMS: a microchannel plate with a phosphorescent screen, a focal plane camera, and an IonCCD array; advances in detector technology will likely improve DOFMS figures-of-merit. In addition, the combination of CMA with TOF detection has provided improved resolution and duty factor over a narrow m/ z range (compared with conventional, single-pass TOFMS). The unique characteristics of DOFMS can enable the intact collection of large biomolecules, clusters, and organisms. DOFMS might also play a key role in achieving the long-sought goal of simultaneous MS/MS.

Development of low-noise CCD drive electronics for the world space observatory ultraviolet spectrograph subsystem

NASA Astrophysics Data System (ADS)

Salter, Mike; Clapp, Matthew; King, James; Morse, Tom; Mihalcea, Ionut; Waltham, Nick; Hayes-Thakore, Chris

2016-07-01

World Space Observatory Ultraviolet (WSO-UV) is a major Russian-led international collaboration to develop a large space-borne 1.7 m Ritchey-Chrétien telescope and instrumentation to study the universe at ultraviolet wavelengths between 115 nm and 320 nm, exceeding the current capabilities of ground-based instruments. The WSO Ultraviolet Spectrograph subsystem (WUVS) is led by the Institute of Astronomy of the Russian Academy of Sciences and consists of two high resolution spectrographs covering the Far-UV range of 115-176 nm and the Near-UV range of 174-310 nm, and a long-slit spectrograph covering the wavelength range of 115-305 nm. The custom-designed CCD sensors and cryostat assemblies are being provided by e2v technologies (UK). STFC RAL Space is providing the Camera Electronics Boxes (CEBs) which house the CCD drive electronics for each of the three WUVS channels. This paper presents the results of the detailed characterisation of the WUVS CCD drive electronics. The electronics include a novel high-performance video channel design that utilises Digital Correlated Double Sampling (DCDS) to enable low-noise readout of the CCD at a range of pixel frequencies, including a baseline requirement of less than 3 electrons rms readout noise for the combined CCD and electronics system at a readout rate of 50 kpixels/s. These results illustrate the performance of this new video architecture as part of a wider electronics sub-system that is designed for use in the space environment. In addition to the DCDS video channels, the CEB provides all the bias voltages and clocking waveforms required to operate the CCD and the system is fully programmable via a primary and redundant SpaceWire interface. The development of the CEB electronics design has undergone critical design review and the results presented were obtained using the engineering-grade electronics box. A variety of parameters and tests are included ranging from general system metrics, such as the power and mass, to more detailed analysis of the video performance including noise, linearity, crosstalk, gain stability and transient response.

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.

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.

High resolution telescope

DOEpatents

Massie, Norbert A.; Oster, Yale

1992-01-01

A large effective-aperture, low-cost optical telescope with diffraction-limited resolution enables ground-based observation of near-earth space objects. The telescope has a non-redundant, thinned-aperture array in a center-mount, single-structure space frame. It employs speckle interferometric imaging to achieve diffraction-limited resolution. The signal-to-noise ratio problem is mitigated by moving the wavelength of operation to the near-IR, and the image is sensed by a Silicon CCD. The steerable, single-structure array presents a constant pupil. The center-mount, radar-like mount enables low-earth orbit space objects to be tracked as well as increases stiffness of the space frame. In the preferred embodiment, the array has elemental telescopes with subaperture of 2.1 m in a circle-of-nine configuration. The telescope array has an effective aperture of 12 m which provides a diffraction-limited resolution of 0.02 arc seconds. Pathlength matching of the telescope array is maintained by an electro-optical system employing laser metrology. Speckle imaging relaxes pathlength matching tolerance by one order of magnitude as compared to phased arrays. Many features of the telescope contribute to substantial reduction in costs. These include eliminating the conventional protective dome and reducing on-site construction activites. The cost of the telescope scales with the first power of the aperture rather than its third power as in conventional telescopes.

Application of linear array imaging techniques to the real-time inspection of airframe structures and substructures

NASA Technical Reports Server (NTRS)

Miller, James G.

1995-01-01

Development and application of linear array imaging technologies to address specific aging-aircraft inspection issues is described. Real-time video-taped images were obtained from an unmodified commercial linear-array medical scanner of specimens constructed to simulate typical types of flaws encountered in the inspection of aircraft structures. Results suggest that information regarding the characteristics, location, and interface properties of specific types of flaws in materials and structures may be obtained from the images acquired with a linear array. Furthermore, linear array imaging may offer the advantage of being able to compare 'good' regions with 'flawed' regions simultaneously, and in real time. Real-time imaging permits the inspector to obtain image information from various views and provides the opportunity for observing the effects of introducing specific interventions. Observation of an image in real-time can offer the operator the ability to 'interact' with the inspection process, thus providing new capabilities, and perhaps, new approaches to nondestructive inspections.

Comparison of characteristics and downstream uniformity of linear-field and cross-field atmospheric pressure plasma jet array in He

NASA Astrophysics Data System (ADS)

Zhang, Bo; Fang, Zhi; Liu, Feng; Zhou, Renwu; Zhou, Ruoyu

2018-06-01

Using an atmospheric pressure plasma jet array is an effective way for expanding the treatment area of a single jet, and generating arrays with well downstream uniformity is of great interest for its applications. In this paper, a plasma jet array in helium is generated in a linear-field jet array with a ring-ring electrode structure excited by alternating current. The characteristics and downstream uniformity of the array and their dependence on the applied voltage and gas flow rate are investigated through optical, electrical, and Schlieren diagnostics. The results are compared with those of our reported work of a cross-field jet array with a needle-ring electrode structure. The results show that the linear-field jet array can generate relatively large-scale plasma with better uniformity and longer plumes than the cross-field case. The divergences observed in gas channels and the plasma plume trajectories are much less than those of the cross-field one. The deflection angle of lateral plumes is less than 6°, which is independent of the gas flow rate and applied voltage. The maximum downstream plumes of 23 mm can be obtained at 7 kV peak applied voltage and 4 l/min gas flow rate. The better uniformity of linear-field jet arrays is due to the effective suppression of hydrodynamic and electrical interactions among the jets in the arrays with a more uniform electric field distribution. The hydrodynamic interaction induced by the gas heating in the linear-field jet array is less than that of the cross-field one. The more uniform electric field distribution in the linear-field jet arrays can reduce the divergence of the propagation trajectories of the plasma plumes. It will generate less residual charge between the adjacent discharges and thus can reduce the accumulation effect of Coulomb force between the plasma plumes. The reported results can help design controllable and scalable plasma jet arrays with well uniformity for material surface and biomedical treatments.

The Acquisition of Development of Advanced Processing Techniques for CCD Arrays.

DTIC Science & Technology

1981-01-01

E57B 96 x 2048 TDI imager production run. A minor change was incorporated on wafers #1-3; an in situ doped-polysilicon technique was used instead of the...2047, - 10 - Ab-A~ and 2048 . In some cases charge collection extends beyond these pixels. The excess signal is measured here as a percentage (Table...amount of spurious charge in pixels #2047 and 2048 is always greater than for pixels #2 and 1, respectively. This is because there is more unshielded area

Scientific, Back-Illuminated CCD Development for the Transiting Exoplanet Survey Satellite

NASA Technical Reports Server (NTRS)

Suntharalingam, V.; Ciampi, J.; Cooper, M. J.; Lambert, R. D.; O'Mara, D. M.; Prigozhin, I.; Young, D. J.; Warner, K.; Burke, B. E.

2015-01-01

We describe the development of the fully depleted, back illuminated charge coupled devices for the Transiting Exoplanet Survey Satellite, which includes a set of four wide angle telescopes, each having a 2x2 array of CCDs. The devices are fabricated on the newly upgraded 200-mm wafer line at Lincoln Laboratory. We discuss methods used to produce the devices and present early performance results from the 100- micron thick, 15x15-microns, 2k x 4k pixel frame transfer CCDs.

Integrated Optical Synthetic Aperture Radar Processor.

DTIC Science & Technology

1987-09-01

acoustooptic cell was employed to input each radar return into a time-and-space integrating optical architecture comprised of several lenses, a CCD area array...acoustooptic cell and parallel rib waveguide structure. During the course of the literature survey, we became aware of an elegant and poten- tially profound...wave.) scatterer at (f , A(t) is the far-field pattern of the antenna. From the geometry of Si. 1. R can be written as [I-2R,/c - nT1 r(t) = A(nT) rectj

Linearly tapered slot antenna circular array for mobile communications

NASA Technical Reports Server (NTRS)

Simons, Rainee N.; Kelly, Eron; Lee, Richard Q.; Taub, Susan R.

1993-01-01

The design, fabrication and testing of a conformal K-band circular array is presented. The array consists of sixteen linearly tapered slot antennas (LTSA). It is fed by a 1:16 microstrip line power splitter via electromagnetic coupling. The array has an omni-directional pattern in the azimuth plane. In the elevation plane the beam is displaced above the horizon.

A linear refractive photovoltaic concentrator solar array flight experiment

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

Jones, P.A.; Murphy, D.M.; Piszczor, M.F.

1995-12-31

Concentrator arrays deliver a number of generic benefits for space including high array efficiency, protection from space radiation effects, and minimized plasma interactions. The line focus concentrator concept delivers two added advantages: (1) low-cost mass production of the lens material and, (2) relaxation of precise array tracking requirements to only a single axis. New array designs emphasize lightweight, high stiffness, stow-ability and ease of manufacture and assembly. The linear refractive concentrator can be designed to provide an essentially flat response over a wide range of longitudinal pointing errors for satellites having only single-axis tracking capability. In this paper the authorsmore » address the current status of the SCARLET linear concentrator program with special emphasis on hardware development of an array-level linear refractive concentrator flight experiment. An aggressive, 6-month development and flight validation program, sponsored by the Ballistic Missile Defense Organization (BMDO) and NASA Lewis Research Center, will quantify and verify SCARLET benefits with in-orbit performance measurements.« less

Comparing simulations and test data of a radiation damaged CCD for the Euclid mission

NASA Astrophysics Data System (ADS)

Skottfelt, Jesper; Hall, David; Gow, Jason; Murray, Neil; Holland, Andrew; Prod'homme, Thibaut

2016-07-01

The radiation damage effects from the harsh radiative environment outside the Earth's atmosphere can be a cause for concern for most space missions. With the science goals becoming ever more demanding, the requirements on the precision of the instruments on board these missions also increases, and it is therefore important to investigate how the radiation induced damage affects the Charge-Coupled Devices (CCDs) that most of these instruments rely on. The primary goal of the Euclid mission is to study the nature of dark matter and dark energy using weak lensing and baryonic acoustic oscillation techniques. The weak lensing technique depends on very precise shape measurements of distant galaxies obtained by a large CCD array. It is anticipated that over the 6 year nominal lifetime of mission, the CCDs will be degraded to an extent that these measurements will not be possible unless the radiation damage effects are corrected. We have therefore created a Monte Carlo model that simulates the physical processes taking place when transferring signal through a radiation damaged CCD. The software is based on Shockley-Read-Hall theory, and is made to mimic the physical properties in the CCD as close as possible. The code runs on a single electrode level and takes charge cloud size and density, three dimensional trap position, and multi-level clocking into account. A key element of the model is that it takes device specific simulations of electron density as a direct input, thereby avoiding to make any analytical assumptions about the size and density of the charge cloud. This paper illustrates how test data and simulated data can be compared in order to further our understanding of the positions and properties of the individual radiation-induced traps.

Off-Grid Direction of Arrival Estimation Based on Joint Spatial Sparsity for Distributed Sparse Linear Arrays

PubMed Central

Liang, Yujie; Ying, Rendong; Lu, Zhenqi; Liu, Peilin

2014-01-01

In the design phase of sensor arrays during array signal processing, the estimation performance and system cost are largely determined by array aperture size. In this article, we address the problem of joint direction-of-arrival (DOA) estimation with distributed sparse linear arrays (SLAs) and propose an off-grid synchronous approach based on distributed compressed sensing to obtain larger array aperture. We focus on the complex source distribution in the practical applications and classify the sources into common and innovation parts according to whether a signal of source can impinge on all the SLAs or a specific one. For each SLA, we construct a corresponding virtual uniform linear array (ULA) to create the relationship of random linear map between the signals respectively observed by these two arrays. The signal ensembles including the common/innovation sources for different SLAs are abstracted as a joint spatial sparsity model. And we use the minimization of concatenated atomic norm via semidefinite programming to solve the problem of joint DOA estimation. Joint calculation of the signals observed by all the SLAs exploits their redundancy caused by the common sources and decreases the requirement of array size. The numerical results illustrate the advantages of the proposed approach. PMID:25420150

Micro-machined high-frequency (80 MHz) PZT thick film linear arrays.

PubMed

Zhou, Qifa; Wu, Dawei; Liu, Changgeng; Zhu, Benpeng; Djuth, Frank; Shung, K

2010-10-01

This paper presents the development of a micromachined high-frequency linear array using PZT piezoelectric thick films. The linear array has 32 elements with an element width of 24 μm and an element length of 4 mm. Array elements were fabricated by deep reactive ion etching of PZT thick films, which were prepared from spin-coating of PZT sol-gel composite. Detailed fabrication processes, especially PZT thick film etching conditions and a novel transferring-and-etching method, are presented and discussed. Array designs were evaluated by simulation. Experimental measurements show that the array had a center frequency of 80 MHz and a fractional bandwidth (-6 dB) of 60%. An insertion loss of -41 dB and adjacent element crosstalk of -21 dB were found at the center frequency.

Multiplexed chemiluminescent assays in ArrayPlates for high-throughput measurement of gene expression

NASA Astrophysics Data System (ADS)

Martel, Ralph R.; Rounseville, Matthew P.; Botros, Ihab W.; Seligmann, Bruce E.

2002-06-01

Multiplexed Molecular Profiling (MMP) assays for drug discovery are performed in ArrayPlates. ArrayPlates are 96- well microtiter plates that contain a 16-element array at the bottom of each well. Each element within an array measures one analyte in a sample. A CCD imager records the quantitative chemiluminescent readout of all 1,536 elements in a 96-well plate simultaneously. Since array elements are reagent modifiable by the end-user, ArrayPlates can be adapted to a broad range of nucleic acid- and protein-based assays. Such multiplexed assays are rapidly established, flexible, robust, automation-friendly and cost-effective. Nucleic acid assays in ArrayPlates can detect DNA and RNA, including SNPs and ESTs. A multiplexed mRNA assay to measure the expression of 16 genes is described. The assay combines a homogeneous nuclease protection assay with subsequent probe immobilization to the array by means of a sandwich hybridization followed with chemiluminescent detection. This assay was used to examine cells grown and treated in microplates and avoided cloning, transfection, RNA insolation, reverse transcription, amplification and fluorochrome labeling. Standard deviations for the measurement of 16 genes ranged from 3 percent to 13 percent in samples of 30,000 cells. Such ArrayPlates transcription assays are useful in drug discovery and development for target validation, screening, lead optimization, metabolism and toxicity profiling. Chemiluminescent detection provides ArrayPlates assays with high signal-to-noise readout and simplifies imager requirements. Imaging a 2D surface that contains arrays simplifies lens requirements relative to imaging columns of liquid in microtiter plate wells. The Omix imager for ArrayPlates is described.

Intra-cavity upconversion to 631 nm of images illuminated by an eye-safe ASE source at 1550 nm.

PubMed

Torregrosa, A J; Maestre, H; Capmany, J

2015-11-15

We report an image wavelength upconversion system. The system mixes an incoming image at around 1550 nm (eye-safe region) illuminated by an amplified spontaneous emission (ASE) fiber source with a Gaussian beam at 1064 nm generated in a continuous-wave diode-pumped Nd(3+):GdVO(4) laser. Mixing takes place in a periodically poled lithium niobate (PPLN) crystal placed intra-cavity. The upconverted image obtained by sum-frequency mixing falls around the 631 nm red spectral region, well within the spectral response of standard silicon focal plane array bi-dimensional sensors, commonly used in charge-coupled device (CCD) or complementary metal-oxide-semiconductor (CMOS) video cameras, and of most image intensifiers. The use of ASE illumination benefits from a noticeable increase in the field of view (FOV) that can be upconverted with regard to using coherent laser illumination. The upconverted power allows us to capture real-time video in a standard nonintensified CCD camera.

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.

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.

A New Remote Sensing Filter Radiometer Employing a Fabry-Perot Etalon and a CCD Camera for Column Measurements of Methane in the Earth Atmosphere

NASA Technical Reports Server (NTRS)

Georgieva, E. M.; Huang, W.; Heaps, W. S.

2012-01-01

A portable remote sensing system for precision column measurements of methane has been developed, built and tested at NASA GSFC. The sensor covers the spectral range from 1.636 micrometers to 1.646 micrometers, employs an air-gapped Fabry-Perot filter and a CCD camera and has a potential to operate from a variety of platforms. The detector is an XS-1.7-320 camera unit from Xenics Infrared solutions which combines an uncooled InGaAs detector array working up to 1.7 micrometers. Custom software was developed in addition to the graphical user basic interface X-Control provided by the company to help save and process the data. The technique and setup can be used to measure other trace gases in the atmosphere with minimal changes of the etalon and the prefilter. In this paper we describe the calibration of the system using several different approaches.

Linear antenna array optimization using flower pollination algorithm.

PubMed

Saxena, Prerna; Kothari, Ashwin

2016-01-01

Flower pollination algorithm (FPA) is a new nature-inspired evolutionary algorithm used to solve multi-objective optimization problems. The aim of this paper is to introduce FPA to the electromagnetics and antenna community for the optimization of linear antenna arrays. FPA is applied for the first time to linear array so as to obtain optimized antenna positions in order to achieve an array pattern with minimum side lobe level along with placement of deep nulls in desired directions. Various design examples are presented that illustrate the use of FPA for linear antenna array optimization, and subsequently the results are validated by benchmarking along with results obtained using other state-of-the-art, nature-inspired evolutionary algorithms such as particle swarm optimization, ant colony optimization and cat swarm optimization. The results suggest that in most cases, FPA outperforms the other evolutionary algorithms and at times it yields a similar performance.

Out-Phased Array Linearized Signaling (OPALS): A Practical Approach to Physical Layer Encryption

DTIC Science & Technology

2015-10-26

Out-Phased Array Linearized Signaling ( OPALS ): A Practical Approach to Physical Layer Encryption Eric Tollefson, Bruce R. Jordan Jr., and Joseph D... OPALS ) which provides a practical approach to physical-layer encryption through spatial masking. Our approach modifies just the transmitter to employ...of the channel. With Out-Phased Array Linearized Signaling ( OPALS ), we propose a new masking technique that has some advantages of each of the

Array biosensor: recent developments

NASA Astrophysics Data System (ADS)

Golden, Joel P.; Rowe-Taitt, Chris A.; Feldstein, Mark J.; Ligler, Frances S.

1999-05-01

A fluorescence-based immunosensor has been developed for simultaneous analyses of multiple samples for 1 to 6 different antigens. A patterned array of recognition antibodies immobilized on the surface of a planar waveguide is used to 'capture' analyte present in samples. Bound analyte is then quantified by means of fluorescent detector molecules. Upon excitation of the fluorescent label by a small diode laser, a CCD camera detects the pattern of fluorescent antigen:antibody complexes on the sensor surface. Image analysis software correlates the position of fluorescent signals with the identity of the analyte. A new design for a fluidics distribution system is shown, as well as results from assays for physiologically relevant concentrations of staphylococcal enterotoxin B (SEB), F1 antigen from Yersinia pestis, and D- dimer, a marker of sepsis and thrombotic disorders.

Analysis of the Bayesian Cramér-Rao lower bound in astrometry. Studying the impact of prior information in the location of an object

NASA Astrophysics Data System (ADS)

Echeverria, Alex; Silva, Jorge F.; Mendez, Rene A.; Orchard, Marcos

2016-10-01

Context. The best precision that can be achieved to estimate the location of a stellar-like object is a topic of permanent interest in the astrometric community. Aims: We analyze bounds for the best position estimation of a stellar-like object on a CCD detector array in a Bayesian setting where the position is unknown, but where we have access to a prior distribution. In contrast to a parametric setting where we estimate a parameter from observations, the Bayesian approach estimates a random object (I.e., the position is a random variable) from observations that are statistically dependent on the position. Methods: We characterize the Bayesian Cramér-Rao (CR) that bounds the minimum mean square error (MMSE) of the best estimator of the position of a point source on a linear CCD-like detector, as a function of the properties of detector, the source, and the background. Results: We quantify and analyze the increase in astrometric performance from the use of a prior distribution of the object position, which is not available in the classical parametric setting. This gain is shown to be significant for various observational regimes, in particular in the case of faint objects or when the observations are taken under poor conditions. Furthermore, we present numerical evidence that the MMSE estimator of this problem tightly achieves the Bayesian CR bound. This is a remarkable result, demonstrating that all the performance gains presented in our analysis can be achieved with the MMSE estimator. Conclusions: The Bayesian CR bound can be used as a benchmark indicator of the expected maximum positional precision of a set of astrometric measurements in which prior information can be incorporated. This bound can be achieved through the conditional mean estimator, in contrast to the parametric case where no unbiased estimator precisely reaches the CR bound.

Expression of a Diverse Array of Ca2+-Activated K+ Channels (SK1/3, IK1, BK) that Functionally Couple to the Mechanosensitive TRPV4 Channel in the Collecting Duct System of Kidney.

PubMed

Li, Yue; Hu, Hongxiang; Butterworth, Michael B; Tian, Jin-Bin; Zhu, Michael X; O'Neil, Roger G

2016-01-01

The voltage- and Ca2+-activated, large conductance K+ channel (BK, maxi-K) is expressed in the collecting duct system of kidney where it underlies flow- and Ca2+-dependent K+ excretion. To determine if other Ca2+-activated K+ channels (KCa) may participate in this process, mouse kidney and the K+-secreting mouse cortical collecting duct (CCD) cell line, mCCDcl1, were assessed for TRPV4 and KCa channel expression and cross-talk. qPCR mRNA analysis and immunocytochemical staining demonstrated TRPV4 and KCa expression in mCCDcl1 cells and kidney connecting tubule (CNT) and CCD. Three subfamilies of KCa channels were revealed: the high Ca2+-binding affinity small-conductance SK channels, SK1and SK3, the intermediate conductance channel, IK1, and the low Ca2+-binding affinity, BK channel (BKα subunit). Apparent expression levels varied in CNT/CCD where analysis of CCD principal cells (PC) and intercalated cells (IC) demonstrated differential staining: SK1:PCIC, IK1:PC>IC, BKα:PC = IC, and TRPV4:PC>IC. Patch clamp analysis and fluorescence Ca2+ imaging of mCCDcl1 cells demonstrated potent TRPV4-mediated Ca2+ entry and strong functional cross-talk between TRPV4 and KCa channels. TRPV4-mediated Ca2+ influx activated each KCa channel, as evidenced by selective inhibition of KCa channels, with each active KCa channel enhancing Ca2+ entry (due to membrane hyperpolarization). Transepithelial electrical resistance (TEER) analysis of confluent mCCDcl1 cells grown on permeable supports further demonstrated this cross-talk where TRPV4 activation induce a decrease in TEER which was partially restored upon selective inhibition of each KCa channel. It is concluded that SK1/SK3 and IK1 are highly expressed along with BKα in CNT and CCD and are closely coupled to TRPV4 activation as observed in mCCDcl1 cells. The data support a model in CNT/CCD segments where strong cross talk between TRPV4-mediated Ca2+ influx and each KCa channel leads to enhance Ca2+ entry which will support activation of the low Ca2+-binding affinity BK channel to promote BK-mediated K+ secretion.

Results of the engineering run of the Coherent Neutrino Nucleus Interaction Experiment (CONNIE)

NASA Astrophysics Data System (ADS)

Aguilar-Arevalo, A.; Bertou, X.; Bonifazi, C.; Butner, M.; Cancelo, G.; Castañeda Vázquez, A.; Cervantes Vergara, B.; Chavez, C. R.; Da Motta, H.; D'Olivo, J. C.; Dos Anjos, J.; Estrada, J.; Fernandez Moroni, G.; Ford, R.; Foguel, A.; Hernández Torres, K. P.; Izraelevitch, F.; Kavner, A.; Kilminster, B.; Kuk, K.; Lima, H. P., Jr.; Makler, M.; Molina, J.; Moreno-Granados, G.; Moro, J. M.; Paolini, E. E.; Sofo Haro, M.; Tiffenberg, J.; Trillaud, F.; Wagner, S.

2016-07-01

The CONNIE detector prototype is operating at a distance of 30 m from the core of a 3.8 GWth nuclear reactor with the goal of establishing Charge-Coupled Devices (CCD) as a new technology for the detection of coherent elastic neutrino-nucleus scattering. We report on the results of the engineering run with an active mass of 4 g of silicon. The CCD array is described, and the performance observed during the first year is discussed. A compact passive shield was deployed around the detector, producing an order of magnitude reduction in the background rate. The remaining background observed during the run was stable, and dominated by internal contamination in the detector packaging materials. The in-situ calibration of the detector using X-ray lines from fluorescence demonstrates good stability of the readout system. The event rates with the reactor ON and OFF are compared, and no excess is observed coming from nuclear fission at the power plant. The upper limit for the neutrino event rate is set two orders of magnitude above the expectations for the standard model. The results demonstrate the cryogenic CCD-based detector can be remotely operated at the reactor site with stable noise below 2 e- RMS and stable background rates. The success of the engineering test provides a clear path for the upgraded 100 g detector to be deployed during 2016.

Lifting the Veil of Dust from NGC 0959: The Importance of a Pixel-based Two-dimensional Extinction Correction

NASA Astrophysics Data System (ADS)

Tamura, K.; Jansen, R. A.; Eskridge, P. B.; Cohen, S. H.; Windhorst, R. A.

2010-06-01

We present the results of a study of the late-type spiral galaxy NGC 0959, before and after application of the pixel-based dust extinction correction described in Tamura et al. (Paper I). Galaxy Evolution Explorer far-UV, and near-UV, ground-based Vatican Advanced Technology Telescope, UBVR, and Spitzer/Infrared Array Camera 3.6, 4.5, 5.8, and 8.0 μm images are studied through pixel color-magnitude diagrams and pixel color-color diagrams (pCCDs). We define groups of pixels based on their distribution in a pCCD of (B - 3.6 μm) versus (FUV - U) colors after extinction correction. In the same pCCD, we trace their locations before the extinction correction was applied. This shows that selecting pixel groups is not meaningful when using colors uncorrected for dust. We also trace the distribution of the pixel groups on a pixel coordinate map of the galaxy. We find that the pixel-based (two-dimensional) extinction correction is crucial for revealing the spatial variations in the dominant stellar population, averaged over each resolution element. Different types and mixtures of stellar populations, and galaxy structures such as a previously unrecognized bar, become readily discernible in the extinction-corrected pCCD and as coherent spatial structures in the pixel coordinate map.

Isotropic-resolution linear-array-based photoacoustic computed tomography through inverse Radon transform

NASA Astrophysics Data System (ADS)

Li, Guo; Xia, Jun; Li, Lei; Wang, Lidai; Wang, Lihong V.

2015-03-01

Linear transducer arrays are readily available for ultrasonic detection in photoacoustic computed tomography. They offer low cost, hand-held convenience, and conventional ultrasonic imaging. However, the elevational resolution of linear transducer arrays, which is usually determined by the weak focus of the cylindrical acoustic lens, is about one order of magnitude worse than the in-plane axial and lateral spatial resolutions. Therefore, conventional linear scanning along the elevational direction cannot provide high-quality three-dimensional photoacoustic images due to the anisotropic spatial resolutions. Here we propose an innovative method to achieve isotropic resolutions for three-dimensional photoacoustic images through combined linear and rotational scanning. In each scan step, we first elevationally scan the linear transducer array, and then rotate the linear transducer array along its center in small steps, and scan again until 180 degrees have been covered. To reconstruct isotropic three-dimensional images from the multiple-directional scanning dataset, we use the standard inverse Radon transform originating from X-ray CT. We acquired a three-dimensional microsphere phantom image through the inverse Radon transform method and compared it with a single-elevational-scan three-dimensional image. The comparison shows that our method improves the elevational resolution by up to one order of magnitude, approaching the in-plane lateral-direction resolution. In vivo rat images were also acquired.

Kinetics of antigen binding to arrays of antibodies in different sized spots

NASA Technical Reports Server (NTRS)

Sapsford, K. E.; Liron, Z.; Shubin, Y. S.; Ligler, F. S.

2001-01-01

A fluorescence-based array biosensor has been developed which can measure the binding kinetics of an antigen to an immobilized antibody in real time. A patterned array of antibodies immobilized on the surface of a planar waveguide was used to capture a Cy5-labeled antigen present in a solution that was continuously flowed over the surface. The CCD image of the waveguide was monitored continuously for 25 min. The resulting exponential rise in fluorescence signal was determined by image analysis software and fitted to a reaction-limited kinetics model, giving a kf of 3.6 x 10(5) M(-1) s(-1). Different spot sizes were then patterned on the surface of the waveguide using either a PDMS flow cell or laser exposure, producing width sizes ranging from 80 to 1145 microm. It was demonstrated that under flow conditions, the reduction of spot size did not alter the association rate of the antigen with immobilized antibody; however, as the spot width decreased to < 200 nm, the signal intensity also decreased.

Moving-Article X-Ray Imaging System and Method for 3-D Image Generation

NASA Technical Reports Server (NTRS)

Fernandez, Kenneth R. (Inventor)

2012-01-01

An x-ray imaging system and method for a moving article are provided for an article moved along a linear direction of travel while the article is exposed to non-overlapping x-ray beams. A plurality of parallel linear sensor arrays are disposed in the x-ray beams after they pass through the article. More specifically, a first half of the plurality are disposed in a first of the x-ray beams while a second half of the plurality are disposed in a second of the x-ray beams. Each of the parallel linear sensor arrays is oriented perpendicular to the linear direction of travel. Each of the parallel linear sensor arrays in the first half is matched to a corresponding one of the parallel linear sensor arrays in the second half in terms of an angular position in the first of the x-ray beams and the second of the x-ray beams, respectively.

Micro-Machined High-Frequency (80 MHz) PZT Thick Film Linear Arrays

PubMed Central

Zhou, Qifa; Wu, Dawei; Liu, Changgeng; Zhu, Benpeng; Djuth, Frank; Shung, K. Kirk

2010-01-01

This paper presents the development of a micro-machined high-frequency linear array using PZT piezoelectric thick films. The linear array has 32 elements with an element width of 24 μm and an element length of 4 mm. Array elements were fabricated by deep reactive ion etching of PZT thick films, which were prepared from spin-coating of PZT solgel composite. Detailed fabrication processes, especially PZT thick film etching conditions and a novel transferring-and-etching method, are presented and discussed. Array designs were evaluated by simulation. Experimental measurements show that the array had a center frequency of 80 MHz and a fractional bandwidth (−6 dB) of 60%. An insertion loss of −41 dB and adjacent element crosstalk of −21 dB were found at the center frequency. PMID:20889407

Reliability of Central Adiposity Assessments Using B-Mode Ultrasound: A Comparison of Linear and Curved Array Transducers.

PubMed

Stoner, Lee; Geoffron, Morgane; Cornwall, Jon; Chinn, Victoria; Gram, Martin; Credeur, Daniel; Fryer, Simon

2016-12-01

Recently, it was reported that intra-abdominal thickness (IAT) assessments using ultrasound are most reliable if measured from the linea alba to the anterior vertebral column. These 2 anatomical sites can be simultaneously visualized using a linear array transducer. Linear array transducers have different operational characteristics when compared with conventional curved array transducers and are more reliable for some ultrasound-derived measures such as abdominal subcutaneous fat thickness. However, it is unknown whether linear array transducers facilitate more reliable IAT measurements than curved array transducers. The purpose of the current study was to (1) compare the reliability of linear and curved array transducer assessments of IAT and maximal abdominal ratio (MAR) and (2) use the findings to update central adiposity measurement guidelines. Fifteen healthy adults (mean [SD], 27 [10] years; 60% female) with a range of somatotypes (body mass index: mean [SD], 24 [4]; range, 19-33 kg/m; waist circumference: mean [SD], 75 [11]; range, 61-96 cm) were tested on 3 mornings under standardized conditions. Intra-abdominal thickness was assessed 2 cm above the umbilicus (transverse plane), measuring from linea alba to the anterior vertebral column. Maximal abdominal ratio was defined as the ratio of IAT to abdominal subcutaneous fat thickness. The IAT range was 25 to 87 mm, and the MAR range was 0.15 to 0.77. Between-day intraclass correlation coefficient values for IAT measurements made were comparable (0.96-0.97) for both transducers, as were MAR values (0.95). In conclusion, while both transducers provided equally reliable measurement of IAT, the use of a single linear array transducer simplifies the assessment of central adiposity.

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.

Optimized Hyper Beamforming of Linear Antenna Arrays Using Collective Animal Behaviour

PubMed Central

Ram, Gopi; Mandal, Durbadal; Kar, Rajib; Ghoshal, Sakti Prasad

2013-01-01

A novel optimization technique which is developed on mimicking the collective animal behaviour (CAB) is applied for the optimal design of hyper beamforming of linear antenna arrays. Hyper beamforming is based on sum and difference beam patterns of the array, each raised to the power of a hyperbeam exponent parameter. The optimized hyperbeam is achieved by optimization of current excitation weights and uniform interelement spacing. As compared to conventional hyper beamforming of linear antenna array, real coded genetic algorithm (RGA), particle swarm optimization (PSO), and differential evolution (DE) applied to the hyper beam of the same array can achieve reduction in sidelobe level (SLL) and same or less first null beam width (FNBW), keeping the same value of hyperbeam exponent. Again, further reductions of sidelobe level (SLL) and first null beam width (FNBW) have been achieved by the proposed collective animal behaviour (CAB) algorithm. CAB finds near global optimal solution unlike RGA, PSO, and DE in the present problem. The above comparative optimization is illustrated through 10-, 14-, and 20-element linear antenna arrays to establish the optimization efficacy of CAB. PMID:23970843

Microstrip antenna developments at JPL

NASA Technical Reports Server (NTRS)

Huang, John

1991-01-01

The in-house development of microstrip antennas, initiated in 1981, when a spaceborne lightweight and low-profile planar array was needed for a satellite communication system, is described. The work described covers the prediction of finite-ground-plane effects by the geometric theory of diffraction, higher-order-mode circularly polarized circular patch antennas, circularly polarized microstrip arrays with linearly polarized elements, an impedance-matching teardrop-shaped probe feed, a dual-polarized microstrip array with high isolation and low cross-polarization, a planar microstrip Yagi array, a microstrip reflectarray, a Ka-band MMIC array, and a series-fed linear arrays.

A 400 KHz line rate 2048-pixel stitched SWIR linear array

NASA Astrophysics Data System (ADS)

Anchlia, Ankur; Vinella, Rosa M.; Gielen, Daphne; Wouters, Kristof; Vervenne, Vincent; Hooylaerts, Peter; Deroo, Pieter; Ruythooren, Wouter; De Gaspari, Danny; Das, Jo; Merken, Patrick

2016-05-01

Xenics has developed a family of stitched SWIR long linear arrays that operate up to 400 KHz of line rate. These arrays serve medical and industrial applications that require high line rates as well as space applications that require long linear arrays. The arrays are based on a modular ROIC design concept: modules of 512 pixels are stitched during fabrication to achieve 512, 1024 and 2048 pixel arrays. Each 512-pixel module has its own on-chip digital sequencer, analog readout chain and 4 output buffers. This modular concept enables a long array to run at a high line rates irrespective of the array length, which limits the line rate in a traditional linear array. The ROIC is flip-chipped with InGaAs detector arrays. The FPA has a pixel pitch of 12.5μm and has two pixel flavors: square (12.5μm) and rectangular (250μm). The frontend circuit is based on Capacitive Trans-impedance Amplifier (CTIA) to attain stable detector bias, and good linearity and signal integrity, especially at high speeds. The CTIA has an input auto-zero mechanism that allows to have low detector bias (<20mV). An on-chip Correlated Double Sample (CDS) facilitates removal of CTIA KTC and 1/f noise, and other offsets, achieving low noise performance. There are five gain modes in the FPA giving the full well range from 85Ke- to 40Me-. The measured input referred noise is 35e-rms in the highest gain mode. The FPA operates in Integrate While Read mode and, at a master clock rate of 60MHz and a minimum integration time of 1.4μs, achieves the highest line rate of 400 KHz. In this paper, design details and measurements results are presented in order to demonstrate the array performance.

Design of measuring system for wire diameter based on sub-pixel edge detection algorithm

NASA Astrophysics Data System (ADS)

Chen, Yudong; Zhou, Wang

2016-09-01

Light projection method is often used in measuring system for wire diameter, which is relatively simpler structure and lower cost, and the measuring accuracy is limited by the pixel size of CCD. Using a CCD with small pixel size can improve the measuring accuracy, but will increase the cost and difficulty of making. In this paper, through the comparative analysis of a variety of sub-pixel edge detection algorithms, polynomial fitting method is applied for data processing in measuring system for wire diameter, to improve the measuring accuracy and enhance the ability of anti-noise. In the design of system structure, light projection method with orthogonal structure is used for the detection optical part, which can effectively reduce the error caused by line jitter in the measuring process. For the electrical part, ARM Cortex-M4 microprocessor is used as the core of the circuit module, which can not only drive double channel linear CCD but also complete the sampling, processing and storage of the CCD video signal. In addition, ARM microprocessor can complete the high speed operation of the whole measuring system for wire diameter in the case of no additional chip. The experimental results show that sub-pixel edge detection algorithm based on polynomial fitting can make up for the lack of single pixel size and improve the precision of measuring system for wire diameter significantly, without increasing hardware complexity of the entire system.

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

General Model of Photon-Pair Detection with an Image Sensor

NASA Astrophysics Data System (ADS)

Defienne, Hugo; Reichert, Matthew; Fleischer, Jason W.

2018-05-01

We develop an analytic model that relates intensity correlation measurements performed by an image sensor to the properties of photon pairs illuminating it. Experiments using an effective single-photon counting camera, a linear electron-multiplying charge-coupled device camera, and a standard CCD camera confirm the model. The results open the field of quantum optical sensing using conventional detectors.

Color management in textile application

NASA Astrophysics Data System (ADS)

De Lucia, Maurizio; Vannucci, Massimiliano; Buonopane, Massimo; Fabroni, Cosimo; Fabrini, Francesco

2002-03-01

The aim of this research was to study a system of acquisition and processing of images capable of confronting colored wool with a reference specimen, in order to define the conformity using objective parameters. The first step of the research was to comprise and to analyze in depth the problem: there has been numerous implications of technical, physical, cultural, biological and also psychological character, that come down from the attempt of giving a quantitative appraisal to the color. In the scene of the national and international scientific and technological research, little has been made as regards measurement of color through digital processing of the images through linear CCD. The reason is fundamentally of technological nature: only during the last years we found the presence on the market of low cost equipment capable of acquiring and processing images with adequate performances and qualities. The job described has permitted to create a first prototype of system for the color measuring with use of CCD linear devices. -Hardware identification to carry out a series of tests and experiments in laboratory. -Verification of such device in a textile facility. -Statistics analysis of the collected data and of the employed models.

A conceptual design study for a two-dimensional, electronically scanned thinned array radiometer

NASA Technical Reports Server (NTRS)

Mutton, Philip; Chromik, Christopher C.; Dixon, Iain; Statham, Richard B.; Stillwagen, Frederic H.; Vontheumer, Alfred E.; Sasamoto, Washito A.; Garn, Paul A.; Cosgrove, Patrick A.; Ganoe, George G.

1993-01-01

A conceptual design for the Two-Dimensional, Electronically Steered Thinned Array Radiometer (ESTAR) is described. This instrument is a synthetic aperture microwave radiometer that operates in the L-band frequency range for the measurement of soil moisture and ocean salinity. Two auxiliary instruments, an 8-12 micron, scanning infrared radiometer and a 0.4-1.0 micron, charge coupled device (CCD) video camera, are included to provided data for sea surface temperature measurements and spatial registration of targets respectively. The science requirements were defined by Goddard Space Flight Center. Instrument and the spacecraft configurations are described for missions using the Pegasus and Taurus launch vehicles. The analyses and design trades described include: estimations of size, mass and power, instrument viewing coverage, mechanical design trades, structural and thermal analyses, data and communications performance assessments, and cost estimation.

Holographic method for site-resolved detection of a 2D array of ultracold atoms

NASA Astrophysics Data System (ADS)

Hoffmann, Daniel Kai; Deissler, Benjamin; Limmer, Wolfgang; Hecker Denschlag, Johannes

2016-08-01

We propose a novel approach to site-resolved detection of a 2D gas of ultracold atoms in an optical lattice. A near-resonant laser beam is coherently scattered by the atomic array, and after passing a lens its interference pattern is holographically recorded by superimposing it with a reference laser beam on a CCD chip. Fourier transformation of the recorded intensity pattern reconstructs the atomic distribution in the lattice with single-site resolution. The holographic detection method requires only about two hundred scattered photons per atom in order to achieve a high reconstruction fidelity of 99.9 %. Therefore, additional cooling during detection might not be necessary even for light atomic elements such as lithium. Furthermore, first investigations suggest that small aberrations of the lens can be post-corrected in imaging processing.

Single-exposure two-dimensional superresolution in digital holography using a vertical cavity surface-emitting laser source array.

PubMed

Granero, Luis; Zalevsky, Zeev; Micó, Vicente

2011-04-01

We present a new implementation capable of producing two-dimensional (2D) superresolution (SR) imaging in a single exposure by aperture synthesis in digital lensless Fourier holography when using angular multiplexing provided by a vertical cavity surface-emitting laser source array. The system performs the recording in a single CCD snapshot of a multiplexed hologram coming from the incoherent addition of multiple subholograms, where each contains information about a different 2D spatial frequency band of the object's spectrum. Thus, a set of nonoverlapping bandpass images of the input object can be recovered by Fourier transformation (FT) of the multiplexed hologram. The SR is obtained by coherent addition of the information contained in each bandpass image while generating an enlarged synthetic aperture. Experimental results demonstrate improvement in resolution and image quality.

Variable optical filters for earth-observation imaging minispectrometers

NASA Astrophysics Data System (ADS)

Piegari, A.; Bulir, J.; Krasilnikova, A.; Dami, M.; Harnisch, B.

2017-11-01

Small-dimension, low-mass spectrometers are useful for both Earth observation and planetary missions. A very compact multi-spectral mini-spectrometer that contains no moving parts, can be constructed combining a graded-thickness filter, having a spatially variable narrow-band transmission, to a CCD array detector. The peak wavelength of the transmission filter is moving along one direction of the filter surface, such that each line of a two-dimensional array detector, equipped with this filter, will detect radiation in a different pass band. The spectrum of interest for image spectrometry of the Earth surface is very wide, 400-1000nm. This requirement along with the need of a very small dimension, makes this filter very difficult to manufacture. Preliminary results on metal-dielectric wedge filters, with a gradient of the transmission peak wavelength equal to 60nm/mm, are reported.

Superresolution with the focused plenoptic camera

NASA Astrophysics Data System (ADS)

Georgiev, Todor; Chunev, Georgi; Lumsdaine, Andrew

2011-03-01

Digital images from a CCD or CMOS sensor with a color filter array must undergo a demosaicing process to combine the separate color samples into a single color image. This interpolation process can interfere with the subsequent superresolution process. Plenoptic superresolution, which relies on precise sub-pixel sampling across captured microimages, is particularly sensitive to such resampling of the raw data. In this paper we present an approach for superresolving plenoptic images that takes place at the time of demosaicing the raw color image data. Our approach exploits the interleaving provided by typical color filter arrays (e.g., Bayer filter) to further refine plenoptic sub-pixel sampling. Our rendering algorithm treats the color channels in a plenoptic image separately, which improves final superresolution by a factor of two. With appropriate plenoptic capture we show the theoretical possibility for rendering final images at full sensor resolution.

Integrated Dual Imaging Detector

NASA Technical Reports Server (NTRS)

Rust, David M.

1999-01-01

A new type of image detector was designed to simultaneously analyze the polarization of light at all picture elements in a scene. The integrated Dual Imaging detector (IDID) consists of a lenslet array and a polarizing beamsplitter bonded to a commercial charge coupled device (CCD). The IDID simplifies the design and operation of solar vector magnetographs and the imaging polarimeters and spectroscopic imagers used, for example, in atmosphere and solar research. When used in a solar telescope, the vector magnetic fields on the solar surface. Other applications include environmental monitoring, robot vision, and medical diagnoses (through the eye). Innovations in the IDID include (1) two interleaved imaging arrays (one for each polarization plane); (2) large dynamic range (well depth of 10(exp 5) electrons per pixel); (3) simultaneous readout and display of both images; and (4) laptop computer signal processing to produce polarization maps in field situations.

Performance measurement of commercial electronic still picture cameras

NASA Astrophysics Data System (ADS)

Hsu, Wei-Feng; Tseng, Shinn-Yih; Chiang, Hwang-Cheng; Cheng, Jui-His; Liu, Yuan-Te

1998-06-01

Commercial electronic still picture cameras need a low-cost, systematic method for evaluating the performance. In this paper, we present a measurement method to evaluating the dynamic range and sensitivity by constructing the opto- electronic conversion function (OECF), the fixed pattern noise by the peak S/N ratio (PSNR) and the image shading function (ISF), and the spatial resolution by the modulation transfer function (MTF). The evaluation results of individual color components and the luminance signal from a PC camera using SONY interlaced CCD array as the image sensor are then presented.

Manned observations technology development, FY 1992 report

NASA Technical Reports Server (NTRS)

Israel, Steven

1992-01-01

This project evaluated the suitability of the NASA/JSC developed electronic still camera (ESC) digital image data for Earth observations from the Space Shuttle, as a first step to aid planning for Space Station Freedom. Specifically, image resolution achieved from the Space Shuttle using the current ESC system, which is configured with a Loral 15 mm x 15 mm (1024 x 1024 pixel array) CCD chip on the focal plane of a Nikon F4 camera, was compared to that of current handheld 70 mm Hasselblad 500 EL/M film cameras.

Research on coding and decoding method for digital levels.

PubMed

Tu, Li-fen; Zhong, Si-dong

2011-01-20

A new coding and decoding method for digital levels is proposed. It is based on an area-array CCD sensor and adopts mixed coding technology. By taking advantage of redundant information in a digital image signal, the contradiction that the field of view and image resolution restrict each other in a digital level measurement is overcome, and the geodetic leveling becomes easier. The experimental results demonstrate that the uncertainty of measurement is 1 mm when the measuring range is between 2 m and 100 m, which can meet practical needs.

High resolution telescope including an array of elemental telescopes aligned along a common axis and supported on a space frame with a pivot at its geometric center

DOEpatents

Norbert, M.A.; Yale, O.

1992-04-28

A large effective-aperture, low-cost optical telescope with diffraction-limited resolution enables ground-based observation of near-earth space objects. The telescope has a non-redundant, thinned-aperture array in a center-mount, single-structure space frame. It employes speckle interferometric imaging to achieve diffraction-limited resolution. The signal-to-noise ratio problem is mitigated by moving the wavelength of operation to the near-IR, and the image is sensed by a Silicon CCD. The steerable, single-structure array presents a constant pupil. The center-mount, radar-like mount enables low-earth orbit space objects to be tracked as well as increases stiffness of the space frame. In the preferred embodiment, the array has elemental telescopes with subaperture of 2.1 m in a circle-of-nine configuration. The telescope array has an effective aperture of 12 m which provides a diffraction-limited resolution of 0.02 arc seconds. Pathlength matching of the telescope array is maintained by a electro-optical system employing laser metrology. Speckle imaging relaxes pathlength matching tolerance by one order of magnitude as compared to phased arrays. Many features of the telescope contribute to substantial reduction in costs. These include eliminating the conventional protective dome and reducing on-site construction activities. The cost of the telescope scales with the first power of the aperture rather than its third power as in conventional telescopes. 15 figs.

High resolution telescope including an array of elemental telescopes aligned along a common axis and supported on a space frame with a pivot at its geometric center

DOEpatents

Norbert, Massie A.; Yale, Oster

1992-01-01

A large effective-aperture, low-cost optical telescope with diffraction-limited resolution enables ground-based observation of near-earth space objects. The telescope has a non-redundant, thinned-aperture array in a center-mount, single-structure space frame. It employes speckle interferometric imaging to achieve diffraction-limited resolution. The signal-to-noise ratio problem is mitigated by moving the wavelength of operation to the near-IR, and the image is sensed by a Silicon CCD. The steerable, single-structure array presents a constant pupil. The center-mount, radar-like mount enables low-earth orbit space objects to be tracked as well as increases stiffness of the space frame. In the preferred embodiment, the array has elemental telescopes with subaperture of 2.1 m in a circle-of-nine configuration. The telescope array has an effective aperture of 12 m which provides a diffraction-limited resolution of 0.02 arc seconds. Pathlength matching of the telescope array is maintained by a electro-optical system employing laser metrology. Speckle imaging relaxes pathlength matching tolerance by one order of magnitude as compared to phased arrays. Many features of the telescope contribute to substantial reduction in costs. These include eliminating the conventional protective dome and reducing on-site construction activities. The cost of the telescope scales with the first power of the aperture rather than its third power as in conventional telescopes.

Parallel, confocal, and complete spectrum imager for fluorescent detection of high-density microarray

NASA Astrophysics Data System (ADS)

Bogdanov, Valery L.; Boyce-Jacino, Michael

1999-05-01

Confined arrays of biochemical probes deposited on a solid support surface (analytical microarray or 'chip') provide an opportunity to analysis multiple reactions simultaneously. Microarrays are increasingly used in genetics, medicine and environment scanning as research and analytical instruments. A power of microarray technology comes from its parallelism which grows with array miniaturization, minimization of reagent volume per reaction site and reaction multiplexing. An optical detector of microarray signals should combine high sensitivity, spatial and spectral resolution. Additionally, low-cost and a high processing rate are needed to transfer microarray technology into biomedical practice. We designed an imager that provides confocal and complete spectrum detection of entire fluorescently-labeled microarray in parallel. Imager uses microlens array, non-slit spectral decomposer, and high- sensitive detector (cooled CCD). Two imaging channels provide a simultaneous detection of localization, integrated and spectral intensities for each reaction site in microarray. A dimensional matching between microarray and imager's optics eliminates all in moving parts in instrumentation, enabling highly informative, fast and low-cost microarray detection. We report theory of confocal hyperspectral imaging with microlenses array and experimental data for implementation of developed imager to detect fluorescently labeled microarray with a density approximately 103 sites per cm2.

Application of a single area array detector for acquistion, tracking and point-ahead in space optical communications

NASA Technical Reports Server (NTRS)

Clark, D. L.; Cosgrove, M.; Vanvranken, R.; Park, H.; Fitzmaurice, M.

1989-01-01

Functions of acquisition, tracking, and point-ahead in space optical communications are being combined into a single system utilizing an area array detector. An analysis is presented of the feasibility concept. The key parameters are: optical power less than 1 pW at 0.86 micrometer, acquisition in less than 30 seconds in an acquisition field of view (FOV) of 1 mrad, tracking with 0.5 microrad rms noise at 1000 Hz update rate, and point ahead transfer function precision of 0.25 microrad over a region of 150 microrad. Currently available array detectors were examined. The most demanding specifications are low output noise, a high detection efficiency, a large number of pixels, and frame rates over 1kHz. A proof of concept (POC) demonstration system is currently being built utilizing the Kodak HS-40 detector (a 128 x 128 photodiode array with a 64 channel CCD readout architecture which can be operated at frame rates as high as 40,000/sec). The POC system implements a windowing scheme and special purpose digital signal processing electronic for matched filter acquisition and tracking algorithms.

Calibration and evaluation of CCD spectroradiometers for ground-based and airborne measurements of spectral actinic flux densities

NASA Astrophysics Data System (ADS)

Bohn, Birger; Lohse, Insa

2017-09-01

The properties and performance of charge-coupled device (CCD) array spectroradiometers for the measurement of atmospheric spectral actinic flux densities (280-650 nm) and photolysis frequencies were investigated. These instruments are widely used in atmospheric research and are suitable for aircraft applications because of high time resolutions and high sensitivities in the UV range. The laboratory characterization included instrument-specific properties like the wavelength accuracy, dark signal, dark noise and signal-to-noise ratio (SNR). Spectral sensitivities were derived from measurements with spectral irradiance standards. The calibration procedure is described in detail, and a straightforward method to minimize the influence of stray light on spectral sensitivities is introduced. From instrument dark noise, minimum detection limits ≈ 1 × 1010 cm-2 s-1 nm-1 were derived for spectral actinic flux densities at wavelengths around 300 nm (1 s integration time). As a prerequisite for the determination of stray light under field conditions, atmospheric cutoff wavelengths were defined using radiative transfer calculations as a function of the solar zenith angle (SZA) and total ozone column (TOC). The recommended analysis of field data relies on these cutoff wavelengths and is also described in detail taking data from a research flight on HALO (High Altitude and Long Range Research Aircraft) as an example. An evaluation of field data was performed by ground-based comparisons with a double-monochromator-based, highly sensitive reference spectroradiometer. Spectral actinic flux densities were compared as well as photolysis frequencies j(NO2) and j(O1D), representing UV-A and UV-B ranges, respectively. The spectra expectedly revealed increased daytime levels of stray-light-induced signals and noise below atmospheric cutoff wavelengths. The influence of instrument noise and stray-light-induced noise was found to be insignificant for j(NO2) and rather limited for j(O1D), resulting in estimated detection limits of 5 × 10-7 and 1 × 10-7 s-1, respectively, derived from nighttime measurements on the ground (0.3 s integration time, 10 s averages). For j(O1D) the detection limit could be further reduced by setting spectral actinic flux densities to zero below atmospheric cutoff wavelengths. The accuracies of photolysis frequencies were determined from linear regressions with data from the double-monochromator reference instrument. The agreement was typically within ±5 %. Because optical-receiver aspects are not specific for the CCD spectroradiometers, they were widely excluded in this work and will be treated in a separate paper, in particular with regard to airborne applications.

Design, Fabrication and Characterization of A Bi-Frequency Co-Linear Array

PubMed Central

Wang, Zhuochen; Li, Sibo; Czernuszewicz, Tomasz J; Gallippi, Caterina M.; Liu, Ruibin; Geng, Xuecang

2016-01-01

Ultrasound imaging with high resolution and large penetration depth has been increasingly adopted in medical diagnosis, surgery guidance, and treatment assessment. Conventional ultrasound works at a particular frequency, with a −6 dB fractional bandwidth of ~70 %, limiting the imaging resolution or depth of field. In this paper, a bi-frequency co-linear array with resonant frequencies of 8 MHz and 20 MHz was investigated to meet the requirements of resolution and penetration depth for a broad range of ultrasound imaging applications. Specifically, a 32-element bi-frequency co-linear array was designed and fabricated, followed by element characterization and real-time sectorial scan (S-scan) phantom imaging using a Verasonics system. The bi-frequency co-linear array was tested in four different modes by switching between low and high frequencies on transmit and receive. The four modes included the following: (1) transmit low, receive low, (2) transmit low, receive high, (3) transmit high, receive low, (4) transmit high, receive high. After testing, the axial and lateral resolutions of all modes were calculated and compared. The results of this study suggest that bi-frequency co-linear arrays are potential aids for wideband fundamental imaging and harmonic/sub-harmonic imaging. PMID:26661069

Multispectral Stokes polarimetry for dermatoscopic imaging

NASA Astrophysics Data System (ADS)

Castillejos, Y.; Martínez-Ponce, Geminiano; Mora-Nuñez, Azael; Castro-Sanchez, R.

2015-12-01

Most of skin pathologies, including melanoma and basal/squamous cell carcinoma, are related to alterations in external and internal order. Usually, physicians rely on their empirical expertise to diagnose these ills normally assisted with dermatoscopes. When there exists skin cancer suspicion, a cytology or biopsy is made, but both laboratory tests imply an invasive procedure. In this regard, a number of non-invasive optical techniques have been proposed recently to improve the diagnostic certainty and assist in the early detection of cutaneous cancer. Herein, skin optical properties are derived with a multispectral polarimetric dermatoscope using three different illumination wavelength intervals centered at 470, 530 and 635nm. The optical device consist of two polarizing elements, a quarter-wave plate and a linear polarizer, rotating at a different angular velocity and a CCD array as the photoreceiver. The modulated signal provided by a single pixel in the acquired image sequence is analyzed with the aim of computing the Stokes parameters. Changes in polarization state of selected wavelengths provide information about the presence of skin pigments such as melanin and hemoglobin species as well as collagen structure, among other components. These skin attributes determine the local physiology or pathology. From the results, it is concluded that optical polarimetry will provide additional elements to dermatologists in their diagnostic task.

Measurement of glyoxal using an incoherent broadband cavity enhanced absorption spectrometer

NASA Astrophysics Data System (ADS)

Washenfelder, R. A.; Langford, A. O.; Fuchs, H.; Brown, S. S.

2008-12-01

We describe an instrument for simultaneous measurements of glyoxal (CHOCHO) and nitrogen dioxide (NO2) using cavity enhanced absorption spectroscopy with a broadband light source. The output of a Xenon arc lamp is coupled into a 1 m optical cavity, and the spectrum of light exiting the cavity is recorded by a grating spectrometer with a charge-coupled device (CCD) array detector. The mirror reflectivity and effective path lengths are determined from the known Rayleigh scattering of He and dry zero air (N2+O2). Least-squares fitting, using published reference spectra, allow the simultaneous retrieval of CHOCHO, NO2, O4, and H2O in the 441 to 469 nm spectral range. For a 1-min sampling time, the precision (±1σ) on signal for measurements of CHOCHO and NO2 is 29 pptv and 20 pptv, respectively. We directly compare measurements made with the incoherent broadband cavity enhanced absorption spectrometer with those from cavity ringdown instruments detecting CHOCHO and NO2 at 404 and 532 nm, respectively, and find linear agreement over a wide range of concentrations. The instrument has been tested in the laboratory with both synthetic and real air samples, and the demonstrated sensitivity and specificity suggest a strong potential for field measurements of both CHOCHO and NO2.

A Simple Method Based on the Application of a CCD Camera as a Sensor to Detect Low Concentrations of Barium Sulfate in Suspension

PubMed Central

de Sena, Rodrigo Caciano; Soares, Matheus; Pereira, Maria Luiza Oliveira; da Silva, Rogério Cruz Domingues; do Rosário, Francisca Ferreira; da Silva, Joao Francisco Cajaiba

2011-01-01

The development of a simple, rapid and low cost method based on video image analysis and aimed at the detection of low concentrations of precipitated barium sulfate is described. The proposed system is basically composed of a webcam with a CCD sensor and a conventional dichroic lamp. For this purpose, software for processing and analyzing the digital images based on the RGB (Red, Green and Blue) color system was developed. The proposed method had shown very good repeatability and linearity and also presented higher sensitivity than the standard turbidimetric method. The developed method is presented as a simple alternative for future applications in the study of precipitations of inorganic salts and also for detecting the crystallization of organic compounds. PMID:22346607

A low-cost, CCD solid state star tracker

NASA Technical Reports Server (NTRS)

Chmielowski, M.; Wynne, D.

1992-01-01

Applied Research Corporation (ARC) has developed an engineering model of a multi-star CCD-based tracker for space applications requiring radiation hardness, high reliability and low power consumption. The engineering unit compared favorably in functional performance tests to the standard NASA single-star tracker. Characteristics of the ARC star tracker are: field of view = 10 deg x 7.5 deg, sensitivity range of -1 to +5 star magnitude, NEA = 3 in x 3 in, linearity = 5 in x 5 in, and power consumption of 1-3 W (operating mode dependent). The software is upgradable through a remote link. The hardware-limited acquisition rate is 1-5 Hz for stars of +2 to +5 magnitude and 10-30 Hz for -1 to +2 magnitude stars. Mechanical and electrical interfaces are identical to the standard NASA star tracker.

Study of Far—Field Directivity Pattern for Linear Arrays

NASA Astrophysics Data System (ADS)

Ana-Maria, Chiselev; Luminita, Moraru; Laura, Onose

2011-10-01

A model to calculate directivity pattern in far field is developed in this paper. Based on this model, the three-dimensional beam pattern is introduced and analyzed in order to investigate geometric parameters of linear arrays and their influences on the directivity pattern. Simulations in azimuthal plane are made to highlight the influence of transducers parameters, including number of elements and inter-element spacing. It is true that these parameters are important factors that influence the directivity pattern and the appearance of side-lobes for linear arrays.

An ANSERLIN array for mobile satellite applications

NASA Technical Reports Server (NTRS)

Colomb, F. Y.; Kunkee, D. B.; Mayes, P. E.; Smith, D. W.; Jamnejad, V.

1990-01-01

Design, analysis, construction, and test of linear arrays of ANSERLIN (annular sector, radiating line) elements are reported and discussed. Due to feeding simplicity and easy construction as well as good CP performance, a planar array composed of a number of such linear arrays each producing a shaped beam tilted in elevation, is a good candidate as a vehicle-mounted mechanically steered antenna for mobile satellite applications. A single level construction technique was developed that makes this type of array very cost competitive with other low-profile arrays. An asymmetric 19.5 inch long four-element array was fabricated and tested with reasonable performance. A smaller five-element symmetric array (16 inch long) was also designed and tested capable of operating in either sense of circular polarization. Efforts were made to successfully reduce this effect.

Microfabricated linear Paul-Straubel ion trap

DOEpatents

Mangan, Michael A [Albuquerque, NM; Blain, Matthew G [Albuquerque, NM; Tigges, Chris P [Albuquerque, NM; Linker, Kevin L [Albuquerque, NM

2011-04-19

An array of microfabricated linear Paul-Straubel ion traps can be used for mass spectrometric applications. Each ion trap comprises two parallel inner RF electrodes and two parallel outer DC control electrodes symmetric about a central trap axis and suspended over an opening in a substrate. Neighboring ion traps in the array can share a common outer DC control electrode. The ions confined transversely by an RF quadrupole electric field potential well on the ion trap axis. The array can trap a wide array of ions.

Jet Noise Source Localization Using Linear Phased Array

NASA Technical Reports Server (NTRS)

Agboola, Ferni A.; Bridges, James

2004-01-01

A study was conducted to further clarify the interpretation and application of linear phased array microphone results, for localizing aeroacoustics sources in aircraft exhaust jet. Two model engine nozzles were tested at varying power cycles with the array setup parallel to the jet axis. The array position was varied as well to determine best location for the array. The results showed that it is possible to resolve jet noise sources with bypass and other components separation. The results also showed that a focused near field image provides more realistic noise source localization at low to mid frequencies.

Iterative color-multiplexed, electro-optical processor.

PubMed

Psaltis, D; Casasent, D; Carlotto, M

1979-11-01

A noncoherent optical vector-matrix multiplier using a linear LED source array and a linear P-I-N photodiode detector array has been combined with a 1-D adder in a feedback loop. The resultant iterative optical processor and its use in solving simultaneous linear equations are described. Operation on complex data is provided by a novel color-multiplexing system.

Multiband selection with linear array detectors

NASA Technical Reports Server (NTRS)

Richard, H. L.; Barnes, W. L.

1985-01-01

Several techniques that can be used in an earth-imaging system to separate the linear image formed after the collecting optics into the desired spectral band are examined. The advantages and disadvantages of the Multispectral Linear Array (MLA) multiple optics, the MLA adjacent arrays, the imaging spectrometer, and the MLA beam splitter are discussed. The beam-splitter design approach utilizes, in addition to relatively broad spectral region separation, a movable Multiband Selection Device (MSD), placed between the exit ports of the beam splitter and a linear array detector, permitting many bands to be selected. The successful development and test of the MSD is described. The device demonstrated the capacity to provide a wide field of view, visible-to-near IR/short-wave IR and thermal IR capability, and a multiplicity of spectral bands and polarization measuring means, as well as a reasonable size and weight at minimal cost and risk compared to a spectrometer design approach.

Fiber bundle phase conjugate mirror

DOEpatents

Ward, Benjamin G.

2012-05-01

An improved method and apparatus for passively conjugating the phases of a distorted wavefronts resulting from optical phase mismatch between elements of a fiber laser array are disclosed. A method for passively conjugating a distorted wavefront comprises the steps of: multiplexing a plurality of probe fibers and a bundle pump fiber in a fiber bundle array; passing the multiplexed output from the fiber bundle array through a collimating lens and into one portion of a non-linear medium; passing the output from a pump collection fiber through a focusing lens and into another portion of the non-linear medium so that the output from the pump collection fiber mixes with the multiplexed output from the fiber bundle; adjusting one or more degrees of freedom of one or more of the fiber bundle array, the collimating lens, the focusing lens, the non-linear medium, or the pump collection fiber to produce a standing wave in the non-linear medium.

Degree-of-Freedom Strengthened Cascade Array for DOD-DOA Estimation in MIMO Array Systems.

PubMed

Yao, Bobin; Dong, Zhi; Zhang, Weile; Wang, Wei; Wu, Qisheng

2018-05-14

In spatial spectrum estimation, difference co-array can provide extra degrees-of-freedom (DOFs) for promoting parameter identifiability and parameter estimation accuracy. For the sake of acquiring as more DOFs as possible with a given number of physical sensors, we herein design a novel sensor array geometry named cascade array. This structure is generated by systematically connecting a uniform linear array (ULA) and a non-uniform linear array, and can provide more DOFs than some exist array structures but less than the upper-bound indicated by minimum redundant array (MRA). We further apply this cascade array into multiple input multiple output (MIMO) array systems, and propose a novel joint direction of departure (DOD) and direction of arrival (DOA) estimation algorithm, which is based on a reduced-dimensional weighted subspace fitting technique. The algorithm is angle auto-paired and computationally efficient. Theoretical analysis and numerical simulations prove the advantages and effectiveness of the proposed array structure and the related algorithm.

Very high frequency (beyond 100 MHz) PZT kerfless linear arrays.

PubMed

Wu, Da-Wei; Zhou, Qifa; Geng, Xuecang; Liu, Chang-Geng; Djuth, Frank; Shung, K Kirk

2009-10-01

This paper presents the design, fabrication, and measurements of very high frequency kerfless linear arrays prepared from PZT film and PZT bulk material. A 12-microm PZT thick film fabricated from PZT-5H powder/solution composite and a piece of 15-microm PZT-5H sheet were used to fabricate 32-element kerfless high-frequency linear arrays with photolithography. The PZT thick film was prepared by spin-coating of PZT sol-gel composite solution. The thin PZT-5H sheet sample was prepared by lapping a PZT-5H ceramic with a precision lapping machine. The measured results of the 2 arrays were compared. The PZT film array had a center frequency of 120 MHz, a bandwidth of 60% with a parylene matching layer, and an insertion loss of 41 dB. The PZT ceramic sheet array was found to have a center frequency of 128 MHz with a poorer bandwidth (40% with a parylene matching layer) but a better sensitivity (28 dB insertion loss).

Very High Frequency (Beyond 100 MHz) PZT Kerfless Linear Arrays

PubMed Central

Wu, Da-Wei; Zhou, Qifa; Geng, Xuecang; Liu, Chang-Geng; Djuth, Frank; Shung, K. Kirk

2010-01-01

This paper presents the design, fabrication, and measurements of very high frequency kerfless linear arrays prepared from PZT film and PZT bulk material. A 12-µm PZT thick film fabricated from PZT-5H powder/solution composite and a piece of 15-µm PZT-5H sheet were used to fabricate 32-element kerfless high-frequency linear arrays with photolithography. The PZT thick film was prepared by spin-coating of PZT sol-gel composite solution. The thin PZT-5H sheet sample was prepared by lapping a PZT-5H ceramic with a precision lapping machine. The measured results of the 2 arrays were compared. The PZT film array had a center frequency of 120 MHz, a bandwidth of 60% with a parylene matching layer, and an insertion loss of 41 dB. The PZT ceramic sheet array was found to have a center frequency of 128 MHz with a poorer bandwidth (40% with a parylene matching layer) but a better sensitivity (28 dB insertion loss). PMID:19942516

Sparse array angle estimation using reduced-dimension ESPRIT-MUSIC in MIMO radar.

PubMed

Zhang, Chaozhu; Pang, Yucai

2013-01-01

Sparse linear arrays provide better performance than the filled linear arrays in terms of angle estimation and resolution with reduced size and low cost. However, they are subject to manifold ambiguity. In this paper, both the transmit array and receive array are sparse linear arrays in the bistatic MIMO radar. Firstly, we present an ESPRIT-MUSIC method in which ESPRIT algorithm is used to obtain ambiguous angle estimates. The disambiguation algorithm uses MUSIC-based procedure to identify the true direction cosine estimate from a set of ambiguous candidate estimates. The paired transmit angle and receive angle can be estimated and the manifold ambiguity can be solved. However, the proposed algorithm has high computational complexity due to the requirement of two-dimension search. Further, the Reduced-Dimension ESPRIT-MUSIC (RD-ESPRIT-MUSIC) is proposed to reduce the complexity of the algorithm. And the RD-ESPRIT-MUSIC only demands one-dimension search. Simulation results demonstrate the effectiveness of the method.

Extraction and Propagation of an Intense Rotating Electron Beam,

DTIC Science & Technology

1982-10-01

radiochromic foils positioned at z = 25 cm. The equal transmission density contours are ranked in linear order of increasing exposure (increasing current...flux encircled by the cathode e = %rc2Bc. Linearizing the equation of motion around the equilibrium, we can find the wavelength of small radial...the beam rotation. The mask which precedes the scint- illator is a linear array of dots while the projection is made up of two disjoint linear arrays

Research on Hartmann test for progressive addition lenses

NASA Astrophysics Data System (ADS)

Qin, Lin-ling; Yu, Jing-chi

2009-05-01

Recently, in the world some growing-up measurements for Progressive addition lenses and relevant equipments have been developed. They are single point measurement, moiré deflectometry, Ronchi test techniques. Hartmann test for Progressive addition lenses is proposed in the article. The measurement principle of Hartmann test for ophthalmic lenses and the power compensation of off-axis rays are introduced. The experimental setup used to test lenses is put forward. For experimental test, a spatial filter is used for selecting a clean Gaussian beam; a collimating lens with focal distance f =300 mm is used to produce collimated beam. The Hartmann plate with a square array of holes separated at 2 mm is selected. The selection of laser and CCD camera is critical to the accuracy of experiment and the image processing algorithm. The spot patterns from CCD are obtained from the experimental tests. The power distribution map for lenses can be obtained by image processing in theory. The results indicate that Hartmann test for Progressive addition lenses is convenient and feasible; also its structure is simple.

Time-resolved spectroscopy using a chopper wheel as a fast shutter

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

Wang, Shicong; Wendt, Amy E.; Boffard, John B.

Widely available, small form-factor, fiber-coupled spectrometers typically have a minimum exposure time measured in milliseconds, and thus cannot be used directly for time-resolved measurements at the microsecond level. Spectroscopy at these faster time scales is typically done with an intensified charge coupled device (CCD) system where the image intensifier acts as a “fast” electronic shutter for the slower CCD array. In this paper, we describe simple modifications to a commercially available chopper wheel system to allow it to be used as a “fast” mechanical shutter for gating a fiber-coupled spectrometer to achieve microsecond-scale time-resolved optical measurements of a periodically pulsedmore » light source. With the chopper wheel synchronized to the pulsing of the light source, the time resolution can be set to a small fraction of the pulse period by using a chopper wheel with narrow slots separated by wide spokes. Different methods of synchronizing the chopper wheel and pulsing of the light sources are explored. The capability of the chopper wheel system is illustrated with time-resolved measurements of pulsed plasmas.« less

Impact localization on composite structures using time difference and MUSIC approach

NASA Astrophysics Data System (ADS)

Zhong, Yongteng; Xiang, Jiawei

2017-05-01

1-D uniform linear array (ULA) has the shortcoming of the half-plane mirror effect, which does not allow discriminating between a target placed above the array and a target placed below the array. This paper presents time difference (TD) and multiple signal classification (MUSIC) based omni-directional impact localization on a large stiffened composite structure using improved linear array, which is able to perform omni-directional 360° localization. This array contains 2M+3 PZT sensors, where 2M+1 PZT sensors are arranged as a uniform linear array, and the other two PZT sensors are placed above and below the array. Firstly, the arrival times of impact signals observed by the other two sensors are determined using the wavelet transform. Compared with each other, the direction range of impact source can be decided in general, 0°to 180° or 180°to 360°. And then, two dimensional multiple signal classification (2D-MUSIC) based spatial spectrum formula using the uniform linear array is applied for impact localization by the general direction range. When the arrival times of impact signals observed by upper PZT is equal to that of lower PZT, the direction can be located in x axis (0°or 180°). And time difference based MUSIC method is present to locate impact position. To verify the proposed approach, the proposed approach is applied to a composite structure. The localization results are in good agreement with the actual impact occurring positions.

SU-F-BRA-16: Development of a Radiation Monitoring Device Using a Low-Cost CCD Camera Following Radionuclide Therapy

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

Taneja, S; Fru, L Che; Desai, V

Purpose: It is now commonplace to handle treatments of hyperthyroidism using iodine-131 as an outpatient procedure due to lower costs and less stringent federal regulations. The Nuclear Regulatory Commission has currently updated release guidelines for these procedures, but there is still a large uncertainty in the dose to the public. Current guidelines to minimize dose to the public require patients to remain isolated after treatment. The purpose of this study was to use a low-cost common device, such as a cell phone, to estimate exposure emitted from a patient to the general public. Methods: Measurements were performed using an Applemore » iPhone 3GS and a Cs-137 irradiator. The charge-coupled device (CCD) camera on the phone was irradiated to exposure rates ranging from 0.1 mR/hr to 100 mR/hr and 30-sec videos were taken during irradiation with the camera lens covered by electrical tape. Interactions were detected as white pixels on a black background in each video. Both single threshold (ST) and colony counting (CC) methods were performed using MATLAB®. Calibration curves were determined by comparing the total pixel intensity output from each method to the known exposure rate. Results: The calibration curve showed a linear relationship above 5 mR/hr for both analysis techniques. The number of events counted per unit exposure rate within the linear region was 19.5 ± 0.7 events/mR and 8.9 ± 0.4 events/mR for the ST and CC methods respectively. Conclusion: Two algorithms were developed and show a linear relationship between photons detected by a CCD camera and low exposure rates, in the range of 5 mR/hr to 100-mR/hr. Future work aims to refine this model by investigating the dose-rate and energy dependencies of the camera response. This algorithm allows for quantitative monitoring of exposure from patients treated with iodine-131 using a simple device outside of the hospital.« less

Flagging and Correction of Pattern Noise in the Kepler Focal Plane Array

NASA Technical Reports Server (NTRS)

Kolodziejczak, Jeffery J.; Caldwell, Douglas A.; VanCleve, Jeffrey E.; Clarke, Bruce D.; Jenkins, Jon M.; Cote, Miles T.; Klaus, Todd C.; Argabright, Vic S.

2010-01-01

In order for Kepler to achieve its required less than 20 PPM photometric precision for magnitude 12 and brighter stars, instrument-induced variations in the CCD readout bias pattern (our "2D black image"), which are either fixed or slowly varying in time, must be identified and the corresponding pixels either corrected or removed from further data processing. The two principle sources of these readout bias variations are crosstalk between the 84 science CCDs and the 4 fine guidance sensor (FGS) CCDs and a high frequency amplifier oscillation on less than 40% of the CCD readout channels. The crosstalk produces a synchronous pattern in the 2D black image with time-variation observed in less than 10% of individual pixel bias histories. We will describe a method of removing the crosstalk signal using continuously-collected data from masked and over-clocked image regions (our "collateral data"), and occasionally-collected full-frame images and reverse-clocked readout signals. We use this same set to detect regions affected by the oscillating amplifiers. The oscillations manifest as time-varying moir pattern and rolling bands in the affected channels. Because this effect reduces the performance in only a small fraction of the array at any given time, we have developed an approach for flagging suspect data. The flags will provide the necessary means to resolve any potential ambiguity between instrument-induced variations and real photometric variations in a target time series. We will also evaluate the effectiveness of these techniques using flight data from background and selected target pixels.

Thermal-Independent Properties of PIN-PMN-PT Single-Crystal Linear-Array Ultrasonic Transducers

PubMed Central

Chen, Ruimin; Wu, Jinchuan; Lam, Kwok Ho; Yao, Liheng; Zhou, Qifa; Tian, Jian; Han, Pengdi; Shung, K. Kirk

2013-01-01

In this paper, low-frequency 32-element linear-array ultrasonic transducers were designed and fabricated using both ternary Pb(In1/2Nb1/2)–Pb(Mg1/3Nb2/3)–PbTiO3 (PIN-PMN-PT) and binary Pb(Mg1/3Nb2/3)–PbTiO3 (PMN-PT) single crystals. Performance of the array transducers was characterized as a function of temperature ranging from room temperature to 160°C. It was found that the array transducers fabricated using the PIN-PMN-PT single crystal were capable of satisfactory performance at 160°C, having a −6-dB bandwidth of 66% and an insertion loss of 37 dB. The results suggest that the potential of PIN-PMN-PT linear-array ultrasonic transducers for high-temperature ultrasonic transducer applications is promising. PMID:23221227

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.

The fast and accurate 3D-face scanning technology based on laser triangle sensors

NASA Astrophysics Data System (ADS)

Wang, Jinjiang; Chang, Tianyu; Ge, Baozhen; Tian, Qingguo; Chen, Yang; Kong, Bin

2013-08-01

A laser triangle scanning method and the structure of 3D-face measurement system were introduced. In presented system, a liner laser source was selected as an optical indicated signal in order to scanning a line one times. The CCD image sensor was used to capture image of the laser line modulated by human face. The system parameters were obtained by system calibrated calculated. The lens parameters of image part of were calibrated with machine visual image method and the triangle structure parameters were calibrated with fine wire paralleled arranged. The CCD image part and line laser indicator were set with a linear motor carry which can achieve the line laser scanning form top of the head to neck. For the nose is ledge part and the eyes are sunk part, one CCD image sensor can not obtain the completed image of laser line. In this system, two CCD image sensors were set symmetric at two sides of the laser indicator. In fact, this structure includes two laser triangle measure units. Another novel design is there laser indicators were arranged in order to reduce the scanning time for it is difficult for human to keep static for longer time. The 3D data were calculated after scanning. And further data processing include 3D coordinate refine, mesh calculate and surface show. Experiments show that this system has simply structure, high scanning speed and accurate. The scanning range covers the whole head of adult, the typical resolution is 0.5mm.

Comparing light sensitivity, linearity and step response of electronic cameras for ophthalmology.

PubMed

Kopp, O; Markert, S; Tornow, R P

2002-01-01

To develop and test a procedure to measure and compare light sensitivity, linearity and step response of electronic cameras. The pixel value (PV) of digitized images as a function of light intensity (I) was measured. The sensitivity was calculated from the slope of the P(I) function, the linearity was estimated from the correlation coefficient of this function. To measure the step response, a short sequence of images was acquired. During acquisition, a light source was switched on and off using a fast shutter. The resulting PV was calculated for each video field of the sequence. A CCD camera optimized for the near-infrared (IR) spectrum showed the highest sensitivity for both, visible and IR light. There are little differences in linearity. The step response depends on the procedure of integration and read out.

Colorimetric Sensor Array for White Wine Tasting.

PubMed

Chung, Soo; Park, Tu San; Park, Soo Hyun; Kim, Joon Yong; Park, Seongmin; Son, Daesik; Bae, Young Min; Cho, Seong In

2015-07-24

A colorimetric sensor array was developed to characterize and quantify the taste of white wines. A charge-coupled device (CCD) camera captured images of the sensor array from 23 different white wine samples, and the change in the R, G, B color components from the control were analyzed by principal component analysis. Additionally, high performance liquid chromatography (HPLC) was used to analyze the chemical components of each wine sample responsible for its taste. A two-dimensional score plot was created with 23 data points. It revealed clusters created from the same type of grape, and trends of sweetness, sourness, and astringency were mapped. An artificial neural network model was developed to predict the degree of sweetness, sourness, and astringency of the white wines. The coefficients of determination (R2) for the HPLC results and the sweetness, sourness, and astringency were 0.96, 0.95, and 0.83, respectively. This research could provide a simple and low-cost but sensitive taste prediction system, and, by helping consumer selection, will be able to have a positive effect on the wine industry.

Colorimetric Sensor Array for White Wine Tasting

PubMed Central

Chung, Soo; Park, Tu San; Park, Soo Hyun; Kim, Joon Yong; Park, Seongmin; Son, Daesik; Bae, Young Min; Cho, Seong In

2015-01-01

A colorimetric sensor array was developed to characterize and quantify the taste of white wines. A charge-coupled device (CCD) camera captured images of the sensor array from 23 different white wine samples, and the change in the R, G, B color components from the control were analyzed by principal component analysis. Additionally, high performance liquid chromatography (HPLC) was used to analyze the chemical components of each wine sample responsible for its taste. A two-dimensional score plot was created with 23 data points. It revealed clusters created from the same type of grape, and trends of sweetness, sourness, and astringency were mapped. An artificial neural network model was developed to predict the degree of sweetness, sourness, and astringency of the white wines. The coefficients of determination (R2) for the HPLC results and the sweetness, sourness, and astringency were 0.96, 0.95, and 0.83, respectively. This research could provide a simple and low-cost but sensitive taste prediction system, and, by helping consumer selection, will be able to have a positive effect on the wine industry. PMID:26213946

Array biosensor for detection of toxins

NASA Technical Reports Server (NTRS)

Ligler, Frances S.; Taitt, Chris Rowe; Shriver-Lake, Lisa C.; Sapsford, Kim E.; Shubin, Yura; Golden, Joel P.

2003-01-01

The array biosensor is capable of detecting multiple targets rapidly and simultaneously on the surface of a single waveguide. Sandwich and competitive fluoroimmunoassays have been developed to detect high and low molecular weight toxins, respectively, in complex samples. Recognition molecules (usually antibodies) were first immobilized in specific locations on the waveguide and the resultant patterned array was used to interrogate up to 12 different samples for the presence of multiple different analytes. Upon binding of a fluorescent analyte or fluorescent immunocomplex, the pattern of fluorescent spots was detected using a CCD camera. Automated image analysis was used to determine a mean fluorescence value for each assay spot and to subtract the local background signal. The location of the spot and its mean fluorescence value were used to determine the toxin identity and concentration. Toxins were measured in clinical fluids, environmental samples and foods, with minimal sample preparation. Results are shown for rapid analyses of staphylococcal enterotoxin B, ricin, cholera toxin, botulinum toxoids, trinitrotoluene, and the mycotoxin fumonisin. Toxins were detected at levels as low as 0.5 ng mL(-1).

Expected progress based on aluminium galium nitride Focal Plan Array for near and deep Ultraviolet

NASA Astrophysics Data System (ADS)

Reverchon, J.-L.; Robin, K.; Bansropun, S.; Gourdel, Y.; Robo, J.-A.; Truffer, J.-P.; Costard, E.; Brault, J.; Frayssinet, E.; Duboz, J.-Y.

The fast development of nitrides has given the opportunity to investigate AlGaN as a material for ultraviolet detection. A camera based on such a material presents an extremely low dark current at room temperature. It can compete with technologies based on photocathodes, MCP intensifiers, back thinned CCD or hybrid CMOS focal plane arrays for low flux measurements. First, we will present results on focal plane array of 320 × 256 pixels with a pitch of 30 μm. The peak responsivity is tuned from 260 nm to 360 nm in different cameras. All these results are obtained in a standard SWIR supply chaine and with AlGaN Schottky diodes grown on sapphire. We will present here the first attempts to transfer the standard design Schottky photodiodes on from sapphire to silicon substrates. We will show the capability to remove the silicon substrate, to etch the window layer in order to extend the band width to lower wavelength and to maintain the AlGaN membrane integrity.

Long linear MWIR and LWIR HgCdTe infrared detection arrays for high resolution imaging

NASA Astrophysics Data System (ADS)

Chamonal, Jean-Paul; Audebert, Patrick; Medina, Philippe; Destefanis, Gérard; Deschamps, Joel R.; Girard, Michel; Chatard, Jean-Pierre

2018-04-01

This paper, "Long linear MWIR and LWIR HgCdTe infrared detection arrays for high resolution imaging," was presented as part of International Conference on Space Optics—ICSO 1997, held in Toulouse, France.

New fabrication of high-frequency (100-MHz) ultrasound PZT film kerfless linear array.

PubMed

Zhu, Benpeng; Chan, Ngai Yui; Dai, Jiyan; Shung, K Kirk; Takeuchi, Shinichi; Zhou, Qifa

2013-04-01

The paper describes the design, fabrication, and measurements of a high-frequency ultrasound kerfless linear array prepared from hydrothermal lead zirconate titanate (PZT) thick film. The 15-μm hydrothermal PZT thick film with an area of 1 × 1 cm, obtained through a self-separation process from Ti substrate, was used to fabricate a 32-element 100-MHz kerfless linear array with photolithography. The bandwidth at -6 dB without matching layer, insertion loss around center frequency, and crosstalk between adjacent elements were measured to be 39%, -30 dB, and -15 dB, respectively.

Linear-array based full-view high-resolution photoacoustic computed tomography of whole mouse brain functions in vivo

NASA Astrophysics Data System (ADS)

Li, Lei; Zhang, Pengfei; Wang, Lihong V.

2018-02-01

Photoacoustic computed tomography (PACT) is a non-invasive imaging technique offering high contrast, high resolution, and deep penetration in biological tissues. We report a photoacoustic computed tomography (PACT) system equipped with a high frequency linear array for anatomical and functional imaging of the mouse whole brain. The linear array was rotationally scanned in the coronal plane to achieve the full-view coverage. We investigated spontaneous neural activities in the deep brain by monitoring the hemodynamics and observed strong interhemispherical correlations between contralateral regions, both in the cortical layer and in the deep regions.

VizieR Online Data Catalog: Mission Accessible Near-Earth Objects Survey (Thirouin+, 2016)

NASA Astrophysics Data System (ADS)

Thirouin, A.; Moskovitz, N.; Binzel, R. P.; Christensen, E.; DeMeo, F. E.; Person, M. J.; Polishook, D.; Thomas, C. A.; Trilling, D.; Willman, M.; Hinkle, M.; Burt, B.; Avner, D.; Aceituno, F. J.

2017-06-01

The data were obtained with the 4.3m Lowell Discovery Channel Telescope (DCT), the 4.1m Southern Astrophysical Research (SOAR) telescope, the 4m Nicholas U. Mayall Telescope, the 2.1m at Kitt Peak Observatory, the 1.8m Perkins telescope, the 1.5m Sierra Nevada Observatory (OSN), and the 1.3m SMARTS telescope between 2013 August and 2015 October. The DCT is forty miles southeast of Flagstaff at the Happy Jack site (Arizona, USA). Images were obtained using the Large Monolithic Imager (LMI), which is a 6144*6160 CCD. The total field of view is 12.5*12.5 with a plate scale of 0.12''/pixel (unbinned). Images were obtained using the 3*3 or 2*2 binning modes. Observations were carried out in situ. The SOAR telescope is located on Cerro Pachon, Chile. Images were obtained using the Goodman High Throughput Spectrograph (Goodman-HTS) instrument in its imaging mode. The instrument consists of a 4096*4096 Fairchild CCD, with a 7.2' diameter field of view (circular field of view) and a plate scale of 0.15''/pixel. Images were obtained using the 2*2 binning mode. Observations were conducted remotely. The Mayall telescope is a 4m telescope located at the Kitt Peak National Observatory (Tucson, Arizona, USA). The National Optical Astronomy Observatory (NOAO) CCD Mosaic-1.1 is a wide field imager composed of an array of eight CCD chips. The field of view is 36'*36', and the plate scale is 0.26''/pixel. Observations were performed remotely. The 2.1m at Kitt Peak Observatory was operated with the STA3 2k*4k CCD, which has a plate scale of 0.305''/pixel and a field of view of 10.2'*6.6'. The instrument was binned 2*2 and the observations were conducted in situ. The Perkins 72'' telescope is located at the Anderson Mesa station at Lowell Observatory (Flagstaff, Arizona, USA). We used the Perkins ReImaging SysteM (PRISM) instrument, a 2*2k Fairchild CCD. The PRISM plate scale is 0.39''/pixel for a field of view of 13'*13'. Observations were performed in situ. The 1.5m telescope located at the OSN at Loma de Dilar in the National Park of Sierra Nevada (Granada, Spain) was operated in situ. Observations were carried out with a 2k*2k CCD, with a total field of view of 7.8'*7.8'. We used 2*2 binning mode, resulting in an effective plate scale of 0.46''/pixel. The 1.3m SMARTS telescope is located at the Cerro Tololo Inter-American Observatory (Coquimbo region, Chile). This telescope is equipped with a camera called ANDICAM (A Novel Dual Imaging CAMera). ANDICAM is a Fairchild 2048*2048 CCD. The pixel scale is 0.371''/pixel, and the field of view is 6'*6'. Observations were carried out in queue mode. (2 data files).

Aerosol Optical Depth Value-Added Product for the SAS-He Instrument

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

Ermold, B; Flynn, CJ; Barnard, J

2013-11-27

The Shortwave Array Spectroradiometer – Hemispheric (SAS-He) is a ground-based, shadowband instrument that measures the direct and diffuse solar irradiance. In this regard, the instrument is similar to the Multi-Filter Rotating Shadowband Radiometer (MFRSR) – an instrument that has been in the ARM suite of instruments for more than 15 years. However, the two instruments differ significantly in wavelength resolution and range. In particular, the MFRSR only observes the spectrum in six discrete wavelength channels of about 10 nm width from 415 to 940 nm. The SAS-He, in contrast, incorporates two fiber-coupled grating spectrometers: a Si CCD spectrometer with overmore » 2000 pixels covering the range from 325-1040 nm with ~ 2.5 nm resolution ,and an InGaAs array spectrometer with 256 pixels covering the wavelength range from 960-1700 nm with ~ 6 nm resolution.« less

Monolithic in-based III-V compound semiconductor focal plane array cell with single stage CCD output

NASA Technical Reports Server (NTRS)

Fossum, Eric R. (Inventor); Cunningham, Thomas J. (Inventor); Krabach, Timothy N. (Inventor); Staller, Craig O. (Inventor)

1994-01-01

A monolithic semiconductor imager includes an indium-based III-V compound semiconductor monolithic active layer of a first conductivity type, an array of plural focal plane cells on the active layer, each of the focal plane cells including a photogate over a top surface of the active layer, a readout circuit dedicated to the focal plane cell including plural transistors formed monolithically with the monolithic active layer and a single-stage charge coupled device formed monolithically with the active layer between the photogate and the readout circuit for transferring photo-generated charge accumulated beneath the photogate during an integration period to the readout circuit. The photogate includes thin epitaxial semiconductor layer of a second conductivity type overlying the active layer and an aperture electrode overlying a peripheral portion of the thin epitaxial semiconductor layer, the aperture electrode being connectable to a photogate bias voltage.

Vision communications based on LED array and imaging sensor

NASA Astrophysics Data System (ADS)

Yoo, Jong-Ho; Jung, Sung-Yoon

2012-11-01

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

Variations of Solar Radius Observed with RHESSI

NASA Astrophysics Data System (ADS)

Fivian, M. D.; Hudson, H. S.; Lin, R. P.

2003-12-01

The Solar Aspect System (SAS) of the rotating (at 15 rpm) RHESSI spacecraft has three subsystems. Each of these measures the position of the limb by sampling the full solar chord profile with a linear CCD using a narrow bandwidth filter at 670 nm. With a resolution of each CCD of 1.7 arcsec/pixel, the accuracy of each of the 6 limb positions is theoretically better than 50 mas using 4 pixels at each limb. Since the launch of RHESSI early 2002, solar limbs are sampled with at least 100 Hz. That provides a database of currently 4 x 109 single radius measurements. The main function of SAS is to determine the RHESSI pointing relative to Sun center. The observed precision of this determination has a typical instantaneous (16 Hz) value of about 200 mas (rms). We show and discuss first results of variations of solar radius observed with RHESSI.

Thermopile Detector Arrays for Space Science Applications

NASA Technical Reports Server (NTRS)

Foote, M. C.; Kenyon, M.; Krueger, T. R.; McCann, T. A.; Chacon, R.; Jones, E. W.; Dickie, M. R.; Schofield, J. T.; McCleese, D. J.; Gaalema, S.

2004-01-01

Thermopile detectors are widely used in uncooled applications where small numbers of detectors are required, particularly in low-cost commercial applications or applications requiring accurate radiometry. Arrays of thermopile detectors, however, have not been developed to the extent of uncooled bolometer and pyroelectric/ferroelectric arrays. Efforts at JPL seek to remedy this deficiency by developing high performance thin-film thermopile detectors in both linear and two-dimensional formats. The linear thermopile arrays are produced by bulk micromachining and wire bonded to separate CMOS readout electronic chips. Such arrays are currently being fabricated for the Mars Climate Sounder instrument, scheduled for launch in 2005. Progress is also described towards realizing a two-dimensional thermopile array built over CMOS readout circuitry in the substrate.

MTF measurement and analysis of linear array HgCdTe infrared detectors

NASA Astrophysics Data System (ADS)

Zhang, Tong; Lin, Chun; Chen, Honglei; Sun, Changhong; Lin, Jiamu; Wang, Xi

2018-01-01

The slanted-edge technique is the main method for measurement detectors MTF, however this method is commonly used on planar array detectors. In this paper the authors present a modified slanted-edge method to measure the MTF of linear array HgCdTe detectors. Crosstalk is one of the major factors that degrade the MTF value of such an infrared detector. This paper presents an ion implantation guard-ring structure which was designed to effectively absorb photo-carriers that may laterally defuse between adjacent pixels thereby suppressing crosstalk. Measurement and analysis of the MTF of the linear array detectors with and without a guard-ring were carried out. The experimental results indicated that the ion implantation guard-ring structure effectively suppresses crosstalk and increases MTF value.

Sonography of the chest using linear-array versus sector transducers: Correlation with auscultation, chest radiography, and computed tomography.

PubMed

Tasci, Ozlem; Hatipoglu, Osman Nuri; Cagli, Bekir; Ermis, Veli

2016-07-08

The primary purpose of our study was to compare the efficacies of two sonographic (US) probes, a high-frequency linear-array probe and a lower-frequency phased-array sector probe in the diagnosis of basic thoracic pathologies. The secondary purpose was to compare the diagnostic performance of thoracic US with auscultation and chest radiography (CXR) using thoracic CT as a gold standard. In total, 55 consecutive patients scheduled for thoracic CT were enrolled in this prospective study. Four pathologic entities were evaluated: pneumothorax, pleural effusion, consolidation, and interstitial syndrome. A portable US scanner was used with a 5-10-MHz linear-array probe and a 1-5-MHz phased-array sector probe. The first probe used was chosen randomly. US, CXR, and auscultation results were compared with the CT results. The linear-array probe had the highest performance in the identification of pneumothorax (83% sensitivity, 100% specificity, and 99% diagnostic accuracy) and pleural effusion (100% sensitivity, 97% specificity, and 98% diagnostic accuracy); the sector probe had the highest performance in the identification of consolidation (89% sensitivity, 100% specificity, and 95% diagnostic accuracy) and interstitial syndrome (94% sensitivity, 93% specificity, and 94% diagnostic accuracy). For all pathologies, the performance of US was superior to those of CXR and auscultation. The linear probe is superior to the sector probe for identifying pleural pathologies, whereas the sector probe is superior to the linear probe for identifying parenchymal pathologies. Thoracic US has better diagnostic performance than CXR and auscultation for the diagnosis of common pathologic conditions of the chest. © 2016 Wiley Periodicals, Inc. J Clin Ultrasound 44:383-389, 2016. © 2016 Wiley Periodicals, Inc.

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.

A K-Band Linear Phased Array Antenna Based on Ba(0.60)Sr(0.40)TiO3 Thin Film Phase Shifters

NASA Technical Reports Server (NTRS)

Romanofsky, R.; Bernhard, J.; Washington, G.; VanKeuls, F.; Miranda, F.; Cannedy, C.

2000-01-01

This paper summarizes the development of a 23.675 GHz linear 16-element scanning phased array antenna based on thin ferroelectric film coupled microstripline phase shifters and microstrip patch radiators.

Preliminary study of the reliability of imaging charge coupled devices

NASA Technical Reports Server (NTRS)

Beall, J. R.; Borenstein, M. D.; Homan, R. A.; Johnson, D. L.; Wilson, D. D.; Young, V. F.

1978-01-01

Imaging CCDs are capable of low light level response and high signal-to-noise ratios. In space applications they offer the user the ability to achieve extremely high resolution imaging with minimum circuitry in the photo sensor array. This work relates the CCD121H Fairchild device to the fundamentals of CCDs and the representative technologies. Several failure modes are described, construction is analyzed and test results are reported. In addition, the relationship of the device reliability to packaging principles is analyzed and test data presented. Finally, a test program is defined for more general reliability evaluation of CCDs.

Measurements of stress evolution during thin film deposition

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

Chason, E.; Floro, J.A.

1996-05-01

We have developed a technique for measuring thin film stress during growth by monitoring the wafer curvature. By measuring the deflection of multiple parallel laser beams with a CCD detector, the sensivity to vibration is reduced and a radius of curvature limit of 4 km has been obtained in situ. This technique also enables us to obtain a 2-dimensional profile of the surface curvature from the simultaneous reflection of a rectangular array of beams. Results from the growth of SiG alloy films are presented to demonstrate the unique information that can be obtained during growth.

Far-ultraviolet MAMA detector imagery and emission-line CCD imagery of NGC 6240

NASA Technical Reports Server (NTRS)

Smith, Andrew M.; Hill, Robert S.; Vrba, Frederick J.; Timothy, J. G.

1992-01-01

An image of the luminous infrared galaxy NGC 6240 at 1480 A was obtained using a multianode microchannel array (MAMA) detector with a rocket-borne telescope. At distances greater than 12 arcsec from the nucleus, the measured ultraviolet luminosity implies intensive star formation activity equal to 2-3 times that of a spiral galaxy such as M83. Optical images in the H-beta and forbidden O III 5007 A emission lines reveal a region of high excitation east of the nucleus between the centers of disks 1 and 2 as described by Bland-Hawthorn et al.

Distributed optical microsensors for hydrogen leak detection and related applications

NASA Astrophysics Data System (ADS)

Hunter, Scott R.; Patton, James F.; Sepaniak, Michael J.; Datskos, Panos G.; Smith, D. Barton

2010-04-01

Significant advances have recently been made to develop optically interrogated microsensor based chemical sensors with specific application to hydrogen vapor sensing and leak detection in the hydrogen economy. We have developed functionalized polymer-film and palladium/silver alloy coated microcantilever arrays with nanomechanical sensing for this application. The uniqueness of this approach is in the use of independent component analysis (ICA) and the classification techniques of neural networks to analyze the signals produced by an array of microcantilever sensors. This analysis identifies and quantifies the amount of hydrogen and other trace gases physisorbed on the arrays. Selectivity is achieved by using arrays of functionalized sensors with a moderate distribution of specificity among the sensing elements. The device consists of an array of beam-shaped transducers with molecular recognition phases (MRPs) applied to one surface of the transducers. Bending moments on the individual transducers can be detected by illuminating them with a laser or an LED and then reading the reflected light with an optical position sensitive detector (PSD) such as a CCD. Judicious selection of MRPs for the array provides multiple isolated interaction surfaces for sensing the environment. When a particular chemical agent binds to a transducer, the effective surface stresses of its modified and uncoated sides change unequally and the transducer begins to bend. The extent of bending depends upon the specific interactions between the microcantilever's MRP and the analyte. Thus, the readout of a multi-MRP array is a complex multidimensional signal that can be analyzed to deconvolve a multicomponent gas mixture. The use of this sensing and analysis technique in unattended networked arrays of sensors for various monitoring and surveillance applications is discussed.

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.

Micromachined poly-SiGe bolometer arrays for infrared imaging and spectroscopy

NASA Astrophysics Data System (ADS)

Leonov, Vladimir N.; Perova, Natalia A.; De Moor, Piet; Du Bois, Bert; Goessens, Claus; Grietens, Bob; Verbist, Agnes; Van Hoof, Chris A.; Vermeiren, Jan P.

2003-03-01

The state-of-the-art characteristics of micromachined polycrystalline SiGe microbolometer arrays are reported. An average NETD of 85 mK at a time constant of 14 ms is already achievable on typical self-supported 50 μm pixels in a linear 64-element array. In order to reach these values, the design optimization was performed based on the performance characteristics of linear 32-, 64- and 128-element arrays of 50-, 60- and 75-μm-pixel bolometers on several detector lots. The infrared and thermal modeling accounting for the read-out properties and self-heating effect in bolometers resulted in improved designs and competitive NETD values of 80 mK on 50 μm pixels in a 160x128 format at standard frame rates and f-number of 1. In parallel, the TCR-to-1/f noise ratio and the mechanical design of the pixels were improved making poly-SiGe a good candidate for a low-cost uncooled thermal array. The technological CMOS-based process possesses an attractive balance between characteristics and price, and allows the micromachining of thin structures, less than 0.2 μm. The resistance and TCR non-uniformity with σ/μ better than 0.2% combined with 99.93% yield are demonstrated. The first lots of fully processed linear arrays have already come from the IMEC process line and the results of characterization are presented. Next year, the first linear and small 2D arrays will be introduced on the market.

A novel biosensor array with a wheel-like pattern for glucose, lactate and choline based on electrochemiluminescence imaging.

PubMed

Zhou, Zhenyu; Xu, Linru; Wu, Suozhu; Su, Bin

2014-10-07

Electrochemiluminescence (ECL) imaging provides a superior approach to achieve array detection because of its ability for ultrasensitive multiplex analysis. In this paper, we reported a novel ECL imaging biosensor array modified with an enzyme/carbon nanotubes/chitosan composite film for the determination of glucose, choline and lactate. The biosensor array was constructed by integrating a patterned indium tin oxide (ITO) glass plate with six perforated poly(dimethylsiloxane) (PDMS) covers. ECL is generated by the electrochemical reaction between luminol and hydrogen peroxide that is produced by the enzyme catalysed oxidation of different substrates with molecular oxygen, and ECL images were captured by a charge-coupled device (CCD) camera. The separated electrochemical micro-cells enabled simultaneous assay of six samples at different concentrations. From the established calibration curves, the detection limits were 14 μM for glucose, 40 μM for lactate and 97 μM for choline, respectively. Moreover, multicomponent assays and cross reactivity were also studied, both of which were satisfied for the analysis. This biosensing platform based on ECL imaging shows many distinct advantages, including miniaturization, low cost, and multi-functionalization. We believe that this novel ECL imaging biosensor platform will have potential applications in clinical diagnostics, medicine and food inspection.

Detector Having A Transmission Grating Beam Splitter For Multi-Wavelength Sample Analysis.

DOEpatents

Liu, Changsheng; Li, Qingbo

2000-09-12

A detector for DNA sample identification is provided with a transmission grating beam splitter (TGBS). The TGBS split fluoresced light from a tagged DNA sample into 0th order and a 1st order components, both of which are detected on a two-dimensional detector array of a CCD camera. The 0th and 1st order components are detected along a column of pixels in the detector array, and are spaced apart from one another. The DNA samples are tagged with four fluorescent dyes, one dye specific for each nucleotide, and all four dyes responding in slightly different manner to the same monochromatic excitation signal. The TGBS splits fluoresced incoming light into 0th and 1st order components, which are then spread out among a number of pixels in the detector array. The 1st component of this light is received by pixels whose position relative to the 0th order component depends on the frequency of fluorescence. Thus, the position at which signal energy is detected on the array is indicative of the particular dye, and therefore, the corresponding nucleotide tagged by that dye. Monitoring signal energy at the 0th order pixel and selected 1st order pixels, provides a set of data from which one may then identify the particular nucleotide.

Detector Having A Transmission Grating Beam Splitter For Multi-Wavelength.

DOEpatents

Liu, Changsheng; Li, Qingbo (State College, PA

1999-12-07

A detector for DNA sample identification is provided with a transmission grating beam splitter (TGBS). The TGBS split fluoresced light from a tagged DNA sample into 0th order and a 1st order components, both of which are detected on a two-dimensional detector array of a CCD camera. The 0th and 1st order components are detected along a column of pixels in the detector array, and are spaced apart from one another. The DNA samples are tagged with four fluorescent dyes, one dye specific for each nucleotide, and all four dyes responding in slightly different manner to the same monochromatic excitation signal. The TGBS splits fluoresced incoming light into 0th and 1st order components, which are then spread out among a number of pixels in the detector array. The 1st component of this light is received by pixels whose position relative to the 0th order component depends on the frequency of fluorescence. Thus, the position at which signal energy is detected on the array is indicative of the particular dye, and therefore, the corresponding nucleotide tagged by that dye. Monitoring signal energy at the 0th order pixel and selected 1st order pixels, provides a set of data from which one may then identify the particular nucleotide.

Co-Prime Frequency and Aperture Design for HF Surveillance, Wideband Radar Imaging, and Nonstationary Array Processing

DTIC Science & Technology

2018-03-01

offset designs . Particularly, the proposed CA-CFO is compared with uniform linear array and uniform frequency offset (ULA-UFO). Uniform linear array...and Aperture Design for HF Surveillance, Wideband Radar Imaging, and Nonstationary Array Processing (Grant No. N00014-13-1-0061) Submitted to...Contents 1. Executive Summary …………………………………………………………………………. 1 1.1. Generalized Co-Prime Array Design ………………………………………………… 1 1.2. Wideband

Mixed Linear/Square-Root Encoded Single Slope Ramp Provides a Fast, Low Noise Analog to Digital Converter with Very High Linearity for Focal Plane Arrays

NASA Technical Reports Server (NTRS)

Wrigley, Christopher James (Inventor); Hancock, Bruce R. (Inventor); Cunningham, Thomas J. (Inventor); Newton, Kenneth W. (Inventor)

2014-01-01

An analog-to-digital converter (ADC) converts pixel voltages from a CMOS image into a digital output. A voltage ramp generator generates a voltage ramp that has a linear first portion and a non-linear second portion. A digital output generator generates a digital output based on the voltage ramp, the pixel voltages, and comparator output from an array of comparators that compare the voltage ramp to the pixel voltages. A return lookup table linearizes the digital output values.

Fast photoacoustic imaging system based on 320-element linear transducer array.

PubMed

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

2004-04-07

A fast photoacoustic (PA) imaging system, based on a 320-transducer linear array, was developed and tested on a tissue phantom. To reconstruct a test tomographic image, 64 time-domain PA signals were acquired from a tissue phantom with embedded light-absorption targets. A signal acquisition was accomplished by utilizing 11 phase-controlled sub-arrays, each consisting of four transducers. The results show that the system can rapidly map the optical absorption of a tissue phantom and effectively detect the embedded light-absorbing target. By utilizing the multi-element linear transducer array and phase-controlled imaging algorithm, we thus can acquire PA tomography more efficiently, compared to other existing technology and algorithms. The methodology and equipment thus provide a rapid and reliable approach to PA imaging that may have potential applications in noninvasive imaging and clinic diagnosis.

Highly Directive Array Aperture

DTIC Science & Technology

2013-02-13

generally to sonar arrays with acoustic discontinuities, and, more particularly, to increasing the directivity gain of a sonar array aperture by...sought by sonar designers. [0005] The following patents and publication show various types of acoustic arrays with coatings and discontinuities that...discloses a sonar array uses multiple acoustically transparent layers. One layer is a linear array of acoustic sensors that is substantially

A Framework for Propagation of Uncertainties in the Kepler Data Analysis Pipeline

NASA Technical Reports Server (NTRS)

Clarke, Bruce D.; Allen, Christopher; Bryson, Stephen T.; Caldwell, Douglas A.; Chandrasekaran, Hema; Cote, Miles T.; Girouard, Forrest; Jenkins, Jon M.; Klaus, Todd C.; Li, Jie;

Space-Time Adaptive Processing for Airborne Radar

DTIC Science & Technology

1994-12-13

horizontal plane Uniform linear antenna array (possibly columns of a planar array) Identical element patterns 13 14 15 9 7 7,33 7 7 Target Model ...Parameters for Example Scenario 31 3 Assumptions Made for Radar System and Signal Model 52 4 Platform and Interference Scenario for Baseline Scenario. 61 5...pulses, is addressed first. Fully adaptive STAP requires the solution to a system of linear equations of size MN, where N is the number of array

High-performance linear arrays of YBa2Cu3O7 superconducting infrared microbolometers on silicon

NASA Astrophysics Data System (ADS)

Johnson, Burgess R.; Foote, Marc C.; Marsh, Holly A.

1995-06-01

Single detectors and linear arrays of microbolometers utilizing the superconducting transition edge of YBa(subscript 2)Cu(subscript 3)O(subscript 7) have been fabricated by micromachining on silicon wafers. A D* of 8 +/- 2 X 10(superscript 9) cm Hz(superscript 1/2)/watt has been measured on a single detector. This is the highest D* reported on any superconducting microbolometer operating at temperatures higher than about 70 K. The NEP of this device was 1.5 X 10(superscript -12) watts/Hz(superscript HLF) at 2 Hz, at a temperature of 80.7 K. The thermal time constant was 105 msec, and the detector area was 140 micrometers X 105 micrometers . The use of batch silicon processing makes fabrication of linear arrays of these detectors relatively straightforward. The measured responsivity of detectors in one such array varied by less than 20% over the 6 mm length of the 64-element linear array. This measurement shows that good uniformity can be achieved at a single operating temperature in a superconductor microbolometer array, even when the superconducting resistive transition is a sharp function of temperature. The thermal detection mechanism of these devices gives them broadband response. This makes them especially useful at long wavelengths (e.g. (lambda) > 20 micrometers ), where they provide very high sensitivity at relatively high operating temperatures.

Characterization of Kerfless Linear Arrays Based on PZT Thick Film.

PubMed

Zawada, Tomasz; Bierregaard, Louise Moller; Ringgaard, Erling; Xu, Ruichao; Guizzetti, Michele; Levassort, Franck; Certon, Dominique

2017-09-01

Multielement transducers enabling novel cost-effective fabrication of imaging arrays for medical applications have been presented earlier. Due to the favorable low lateral coupling of the screen-printed PZT, the elements can be defined by the top electrode pattern only, leading to a kerfless design with low crosstalk between the elements. The thick-film-based linear arrays have proved to be compatible with a commercial ultrasonic scanner and to support linear array beamforming as well as phased array beamforming. The main objective of the presented work is to investigate the performance of the devices at the transducer level by extensive measurements of the test structures. The arrays have been characterized by several different measurement techniques. First, electrical impedance measurements on several elements in air and liquid have been conducted in order to support material parameter identification using the Krimholtz-Leedom-Matthaei model. It has been found that electromechanical coupling is at the level of 35%. The arrays have also been characterized by a pulse-echo system. The measured sensitivity is around -60 dB, and the fractional bandwidth is close to 60%, while the center frequency is about 12 MHz over the whole array. Finally, laser interferometry measurements have been conducted indicating very good displacement level as well as pressure. The in-depth characterization of the array structure has given insight into the performance parameters for the array based on PZT thick film, and the obtained information will be used to optimize the key parameters for the next generation of cost-effective arrays based on piezoelectric thick film.

Multicolor Observations of ASAS 002511+1217.2

NASA Astrophysics Data System (ADS)

Golovin, Alex; Price, Aaron; Templeton, Matthew; Cook, Lewis; Crawford, Timothy; Henden, Arne; James, Robert; Koppelman, Michael; Nelson, Peter Robert; Oksanen, Arto; Pavlenko, Elena; Pickard, Roger; Quinn, Nick; Starkey, Don Ray

2005-04-01

ASAS 002511+1217.2 is a newly discovered cataclysmic variable in Pisces constellation. It was discovered by G. Pojmanski and the ASAS-3 survey on 11.203 (UT) Sept., 2004. The new variable is within the uncertainly boundaries of RX J0025.1+1217, 1RXS J002510.8+121725, 2MASS J00251111+1217121. The AAVSO has collected 31839 CCD observations of ASAS 002511+1217.2 over a 55 day period following its outburst. This is CCD-lightcurve, based on our observations. The errors depend on the observer, but typically can be estimated to be +/- 0.02 for CCD observations. It is interesting to note that so-called an echo-outburst occurred, reaching a maximum at 20 days after super-outburst' maximum. Before combining data for statistical analysis, each observer's data set was individually transformed to an uniform zero-point by subtracting a linear fit from each night's observations. This was done so that we could remove the overall trend of outburst, and to combine all observations into a single data set. The analysis of CCD observations by the Lalfer-Kinman method has enabled us to show the presence of the 0.05701 period of superhumps. The periodogram presents the peak, which corresponds to the mentioned period. This figure shows an example superhump phase diagram with the estimated period. As an example of the superhump profile, we plotted on the phase diagram the superhumps, observed on 20 Sept., by Elena Pavlenko at the Crimean Astrophysical Observatory. The results of this observing-campaign were recently published at 4th of March in Informational Bulletin on Variable Stars of the International Astronomical Union at 5611 issue.

A quantum description of linear, and non-linear optical interactions in arrays of plasmonic nanoparticles

NASA Astrophysics Data System (ADS)

Arabahmadi, Ehsan; Ahmadi, Zabihollah; Rashidian, Bizhan

2018-06-01

A quantum theory for describing the interaction of photons and plasmons, in one- and two-dimensional arrays is presented. Ohmic losses and inter-band transitions are not considered. We use macroscopic approach, and quantum field theory methods including S-matrix expansion, and Feynman diagrams for this purpose. Non-linear interactions are also studied, and increasing the probability of such interactions, and its application are also discussed.

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

An Astronomical Test of CCD Photometric Precision

NASA Technical Reports Server (NTRS)

Koch, David; Dunham, Edward; Borucki, William; Jenkins, Jon; DeVingenzi, D. (Technical Monitor)

1998-01-01

This article considers a posteriori error estimation of specified functionals for first-order systems of conservation laws discretized using the discontinuous Galerkin (DG) finite element method. Using duality techniques. we derive exact error representation formulas for both linear and nonlinear functionals given an associated bilinear or nonlinear variational form. Weighted residual approximations of the exact error representation formula are then proposed and numerically evaluated for Ringleb flow, an exact solution of the 2-D Euler equations.

A chemiluminescence sensor array for discriminating natural sugars and artificial sweeteners.

PubMed

Niu, Weifen; Kong, Hao; Wang, He; Zhang, Yantu; Zhang, Sichun; Zhang, Xinrong

2012-01-01

In this paper, we report a chemiluminescence (CL) sensor array based on catalytic nanomaterials for the discrimination of ten sweeteners, including five natural sugars and five artificial sweeteners. The CL response patterns ("fingerprints") can be obtained for a given compound on the nanomaterial array and then identified through linear discriminant analysis (LDA). Moreover, each pure sweetener was quantified based on the emission intensities of selected sensor elements. The linear ranges for these sweeteners lie within 0.05-100 mM, but vary with the type of sweetener. The applicability of this array to real-life samples was demonstrated by applying it to various beverages, and the results showed that the sensor array possesses excellent discrimination power and reversibility.

Performance analysis of structured gradient algorithm. [for adaptive beamforming linear arrays

NASA Technical Reports Server (NTRS)

Godara, Lal C.

1990-01-01

The structured gradient algorithm uses a structured estimate of the array correlation matrix (ACM) to estimate the gradient required for the constrained least-mean-square (LMS) algorithm. This structure reflects the structure of the exact array correlation matrix for an equispaced linear array and is obtained by spatial averaging of the elements of the noisy correlation matrix. In its standard form the LMS algorithm does not exploit the structure of the array correlation matrix. The gradient is estimated by multiplying the array output with the receiver outputs. An analysis of the two algorithms is presented to show that the covariance of the gradient estimated by the structured method is less sensitive to the look direction signal than that estimated by the standard method. The effect of the number of elements on the signal sensitivity of the two algorithms is studied.

Measurement of glyoxal using an incoherent broadband cavity enhanced absorption spectrometer

NASA Astrophysics Data System (ADS)

Washenfelder, R. A.; Langford, A. O.; Fuchs, H.; Brown, S. S.

2008-08-01

We describe an instrument for simultaneous measurements of glyoxal (CHOCHO) and nitrogen dioxide (NO2) using cavity enhanced absorption spectroscopy with a broadband light source. The output of a Xenon arc lamp is coupled into a 1 m optical cavity, and the spectrum of light exiting the cavity is recorded by a grating spectrometer with a charge-coupled device (CCD) array detector. The mirror reflectivity and effective path lengths are determined from the known Rayleigh scattering of He and dry zero air (N2+O2). Least-squares fitting, using published reference spectra, allow the simultaneous retrieval of CHOCHO, NO2, O4, and H2O in the 441 to 469 nm spectral range. For a 1-min sampling time, the minimum detectable absorption is 4×10-10 cm-1, and the precision (±1σ) on signal for measurements of CHOCHO and NO2 is 29 pptv and 20 pptv, respectively. We directly compare the incoherent broadband cavity enhanced absorption spectrometer to 404 and 532 nm cavity ringdown instruments for CHOCHO and NO2 detection, and find linear agreement over a wide range of concentrations. The instrument has been tested in the laboratory with both synthetic and real air samples, and the demonstrated sensitivity and specificity suggest a strong potential for field measurements of both CHOCHO and NO2.

Adaptive Optics Makes A Research Instrument Out Of A Commercial 30 cm Aperture Telescope

NASA Astrophysics Data System (ADS)

Durig, D. T.

1999-12-01

I recently upgraded my SBIG ST-8 CCD camera with the AO-7 Adaptive Optics unit. This has solved many of the problems with tracking errors and the stability of my telescope mount and allowed me to obtain useful astrometric information on asteroids, comets and supernovae. It is no longer easy to take automated remote images but as long as I am at the observatory, good quality data can be obtained. The AO-7 unit allows me to pick a guide star for the guiding CCD just slightly out of the field of view of the imaging CCD. I am able to guide at the rate of 5 corrections per second with a 13th magnitude guide star. The fastest I have been able to guide is 30 times per second, but there are not usually bright enough stars near the image field to use this rate. When I have to use a dimmer star to guide on, and my rate is as slow as once per two seconds, good results are possible as long as the winds are not too strong. With a focal length of 1775 mm (f/5.75) and 2x2 binning on the CDD I am able to reach at least 18th magnitude objects in a 30 second exposure, but the guiding has to be very good to use these images for astrometry. For objects dimmer than 17th magnitude I normally go to a 2 minute exposure. With this equipment I was the first to observe that a recently discovered object (Comet LINEAR S4) was a comet and not an asteroid as originally reported (see IAUC 7267). I have performed additional astrometric observations on Comets LINEAR S3, S4, T2 and Ferris U1. I have also performed measurements on over a dozen asteroids from the MPC Critical List.

A novel design measuring method based on linearly polarized laser interference

NASA Astrophysics Data System (ADS)

Cao, Yanbo; Ai, Hua; Zhao, Nan

2013-09-01

The interferometric method is widely used in the precision measurement, including the surface quality of the large-aperture mirror. The laser interference technology has been developing rapidly as the laser sources become more and more mature and reliable. We adopted the laser diode as the source for the sake of the short coherent wavelength of it for the optical path difference of the system is quite shorter as several wavelengths, and the power of laser diode is sufficient for measurement and safe to human eye. The 673nm linearly laser was selected and we construct a novel form of interferometric system as we called `Closed Loop', comprised of polarizing optical components, such as polarizing prism and quartz wave plate, the light from the source split by which into measuring beam and referencing beam, they've both reflected by the measuring mirror, after the two beams transforming into circular polarization and spinning in the opposite directions we induced the polarized light synchronous phase shift interference technology to get the detecting fringes, which transfers the phase shifting in time domain to space, so that we did not need to consider the precise-controlled shift of optical path difference, which will introduce the disturbance of the air current and vibration. We got the interference fringes from four different CCD cameras well-alignment, and the fringes are shifted into four different phases of 0, π/2, π, and 3π/2 in time. After obtaining the images from the CCD cameras, we need to align the interference fringes pixel to pixel from different CCD cameras, and synthesis the rough morphology, after getting rid of systematic error, we could calculate the surface accuracy of the measuring mirror. This novel design detecting method could be applied into measuring the optical system aberration, and it would develop into the setup of the portable structural interferometer and widely used in different measuring circumstances.

A High-Speed, Event-Driven, Active Pixel Sensor Readout for Photon-Counting Microchannel Plate Detectors

NASA Technical Reports Server (NTRS)

Kimble, Randy A.; Pain, Bedabrata; Norton, Timothy J.; Haas, J. Patrick; Oegerle, William R. (Technical Monitor)

2002-01-01

Silicon array readouts for microchannel plate intensifiers offer several attractive features. In this class of detector, the electron cloud output of the MCP intensifier is converted to visible light by a phosphor; that light is then fiber-optically coupled to the silicon array. In photon-counting mode, the resulting light splashes on the silicon array are recognized and centroided to fractional pixel accuracy by off-chip electronics. This process can result in very high (MCP-limited) spatial resolution while operating at a modest MCP gain (desirable for dynamic range and long term stability). The principal limitation of intensified CCD systems of this type is their severely limited local dynamic range, as accurate photon counting is achieved only if there are not overlapping event splashes within the frame time of the device. This problem can be ameliorated somewhat by processing events only in pre-selected windows of interest of by using an addressable charge injection device (CID) for the readout array. We are currently pursuing the development of an intriguing alternative readout concept based on using an event-driven CMOS Active Pixel Sensor. APS technology permits the incorporation of discriminator circuitry within each pixel. When coupled with suitable CMOS logic outside the array area, the discriminator circuitry can be used to trigger the readout of small sub-array windows only when and where an event splash has been detected, completely eliminating the local dynamic range problem, while achieving a high global count rate capability and maintaining high spatial resolution. We elaborate on this concept and present our progress toward implementing an event-driven APS readout.

Delta-Doped Back-Illuminated CMOS Imaging Arrays: Progress and Prospects

NASA Technical Reports Server (NTRS)

Hoenk, Michael E.; Jones, Todd J.; Dickie, Matthew R.; Greer, Frank; Cunningham, Thomas J.; Blazejewski, Edward; Nikzad, Shouleh

2009-01-01

In this paper, we report the latest results on our development of delta-doped, thinned, back-illuminated CMOS imaging arrays. As with charge-coupled devices, thinning and back-illumination are essential to the development of high performance CMOS imaging arrays. Problems with back surface passivation have emerged as critical to the prospects for incorporating CMOS imaging arrays into high performance scientific instruments, just as they did for CCDs over twenty years ago. In the early 1990's, JPL developed delta-doped CCDs, in which low temperature molecular beam epitaxy was used to form an ideal passivation layer on the silicon back surface. Comprising only a few nanometers of highly-doped epitaxial silicon, delta-doping achieves the stability and uniformity that are essential for high performance imaging and spectroscopy. Delta-doped CCDs were shown to have high, stable, and uniform quantum efficiency across the entire spectral range from the extreme ultraviolet through the near infrared. JPL has recently bump-bonded thinned, delta-doped CMOS imaging arrays to a CMOS readout, and demonstrated imaging. Delta-doped CMOS devices exhibit the high quantum efficiency that has become the standard for scientific-grade CCDs. Together with new circuit designs for low-noise readout currently under development, delta-doping expands the potential scientific applications of CMOS imaging arrays, and brings within reach important new capabilities, such as fast, high-sensitivity imaging with parallel readout and real-time signal processing. It remains to demonstrate manufacturability of delta-doped CMOS imaging arrays. To that end, JPL has acquired a new silicon MBE and ancillary equipment for delta-doping wafers up to 200mm in diameter, and is now developing processes for high-throughput, high yield delta-doping of fully-processed wafers with CCD and CMOS imaging devices.

Comparison of the Roche Cobas(®) 4800 HPV assay to Digene Hybrid Capture 2, Roche Linear Array and Roche Amplicor for Detection of High-Risk Human Papillomavirus Genotypes in Women undergoing treatment for cervical dysplasia.

PubMed

Phillips, Samuel; Garland, Suzanne M; Tan, Jeffery H; Quinn, Michael A; Tabrizi, Sepehr N

2015-01-01

The recently FDA (U.S. food and drug administration) approved Roche Cobas(®) 4800 (Cobas) human papillomavirus (HPV) has limited performance data compared to current HPV detection methods for test of cure in women undergoing treatment for high grade lesions. Evaluation of Cobas HPV assay using historical samples from women undergoing treatment for cervical dysplasia. A selection of 407 samples was tested on the Cobas assay and compared to previous results from Hybrid Capture 2, HPV Amplicor and Roche Linear Array. Overall, a correlation between high-risk HPV positivity and high grade histological diagnosis was 90.6% by the Cobas, 86.1% by Hybrid Capture 2, 92.9% by HPV Amplicor and 91.8% by Roche Linear Array. The Cobas HPV assay is comparative to both the HPV Amplicor and Roche Linear Array assays and better than Hybrid capture 2 assay in the detection of High-Risk HPV in women undergoing treatment for cervical dysplasia. Copyright © 2014 Elsevier B.V. All rights reserved.

Linear micromechanical stepping drive for pinhole array positioning

NASA Astrophysics Data System (ADS)

Endrödy, Csaba; Mehner, Hannes; Grewe, Adrian; Hoffmann, Martin

2015-05-01

A compact linear micromechanical stepping drive for positioning a 7 × 5.5 mm2 optical pinhole array is presented. The system features a step size of 13.2 µm and a full displacement range of 200 µm. The electrostatic inch-worm stepping mechanism shows a compact design capable of positioning a payload 50% of its own weight. The stepping drive movement, step sizes and position accuracy are characterized. The actuated pinhole array is integrated in a confocal chromatic hyperspectral imaging system, where coverage of the object plane, and therefore the useful picture data, can be multiplied by 14 in contrast to a non-actuated array.

Segmented amplifier configurations for laser amplifier

DOEpatents

Hagen, Wilhelm F.

1979-01-01

An amplifier system for high power lasers, the system comprising a compact array of segments which (1) preserves high, large signal gain with improved pumping efficiency and (2) allows the total amplifier length to be shortened by as much as one order of magnitude. The system uses a three dimensional array of segments, with the plane of each segment being oriented at substantially the amplifier medium Brewster angle relative to the incident laser beam and with one or more linear arrays of flashlamps positioned between adjacent rows of amplifier segments, with the plane of the linear array of flashlamps being substantially parallel to the beam propagation direction.

Dedicated hardware processor and corresponding system-on-chip design for real-time laser speckle imaging.

PubMed

Jiang, Chao; Zhang, Hongyan; Wang, Jia; Wang, Yaru; He, Heng; Liu, Rui; Zhou, Fangyuan; Deng, Jialiang; Li, Pengcheng; Luo, Qingming

2011-11-01

Laser speckle imaging (LSI) is a noninvasive and full-field optical imaging technique which produces two-dimensional blood flow maps of tissues from the raw laser speckle images captured by a CCD camera without scanning. We present a hardware-friendly algorithm for the real-time processing of laser speckle imaging. The algorithm is developed and optimized specifically for LSI processing in the field programmable gate array (FPGA). Based on this algorithm, we designed a dedicated hardware processor for real-time LSI in FPGA. The pipeline processing scheme and parallel computing architecture are introduced into the design of this LSI hardware processor. When the LSI hardware processor is implemented in the FPGA running at the maximum frequency of 130 MHz, up to 85 raw images with the resolution of 640×480 pixels can be processed per second. Meanwhile, we also present a system on chip (SOC) solution for LSI processing by integrating the CCD controller, memory controller, LSI hardware processor, and LCD display controller into a single FPGA chip. This SOC solution also can be used to produce an application specific integrated circuit for LSI processing.

Rocket and laboratory studies in astronomy

NASA Technical Reports Server (NTRS)

Feldman, Paul D.

1994-01-01

This report covers the period from September 1, 1993 to August 31, 1994. During the reporting period we launched the Faint Object Telescope to measure the absolute flux of a hot white dwarf star in the spectral range below 1200 A. This experiment was not successful due to a failure of an electronics unit in the onboard TV acquisition system. The source of the failure has been identified and corrected and is described in detail below. The payload was recovered in excellent condition and we are planning to refurbish it for flight during the November 1995 Australia campaign. We have continued our laboratory studies of the ultraviolet performance of charge-coupled-detector (CCD) arrays and plan to include a UV-sensitive CCD in a new payload that was assembled during the current period. The objective of the experiment is the ultraviolet imaging of Jupiter and we are scheduled to launch the payload, 36.115UG, in May-June 1995. We have also begun the design of a high-resolution FUV spectrograph for a future flight of the FOT and have just recently received a high line density grating fabricated by Jobin-Yvon, S.A. (France) for evaluation. Work has continued on the analysis of data from previous rocket experiments.

Fireball Observations in Visible and Sodium Bands

NASA Astrophysics Data System (ADS)

Fletcher, Sandra

On November 17th at 1:32am MST, a large Leonid fireball was simultaneously imaged by two experiments, a visible band CCD camera and a 590nm filtered band equi-angle fisheye and telecentric lens assembly. The visible band camera, ROTSE (Robotic Optical Transient Search Experiment) is a two by two f/1.9 telephoto lens array with 2k x2k Thompson CCD and is located at 35.87 N, 106.25 W at an altitude of 2115m. One-minute exposures along the radiant were taken of the event for 30 minutes after the initial explosion. The sodium band experiment was located at 35.29 N,106.46 W at an altitude of 1860m. It took ninety second exposures and captured several events throughout the night. Triangulation from two New Mexico sites resulted in an altitude of 83km over Wagon Mound, NM. Two observers present at the ROTSE site saw a green flash and a persistent glow up to seven minutes after the explosion. Cataloging of all sodium trails for comparison with lidar and infrasonic measurements is in progress. The raw data from both experiments and the atmospheric chemistry interpretation of them will be presented.

Experimental Evaluation of the "Polished Panel Optical Receiver" Concept on the Deep Space Network's 34 Meter Antenna

NASA Technical Reports Server (NTRS)

Vilnrotter, Victor A.

2012-01-01

The potential development of large aperture ground-based "photon bucket" optical receivers for deep space communications has received considerable attention recently. One approach currently under investigation proposes to polish the aluminum reflector panels of 34-meter microwave antennas to high reflectance, and accept the relatively large spotsize generated by even state-of-the-art polished aluminum panels. Here we describe the experimental effort currently underway at the Deep Space Network (DSN) Goldstone Communications Complex in California, to test and verify these concepts in a realistic operational environment. A custom designed aluminum panel has been mounted on the 34 meter research antenna at Deep-Space Station 13 (DSS-13), and a remotely controlled CCD camera with a large CCD sensor in a weather-proof container has been installed next to the subreflector, pointed directly at the custom polished panel. Using the planet Jupiter as the optical point-source, the point-spread function (PSF) generated by the polished panel has been characterized, the array data processed to determine the center of the intensity distribution, and expected communications performance of the proposed polished panel optical receiver has been evaluated.

Microtomography with photon counting detectors: improving the quality of tomographic reconstruction by voxel-space oversampling

NASA Astrophysics Data System (ADS)

Dudak, J.; Zemlicka, J.; Karch, J.; Hermanova, Z.; Kvacek, J.; Krejci, F.

2017-01-01

Photon counting detectors Timepix are known for their unique properties enabling X-ray imaging with extremely high contrast-to-noise ratio. Their applicability has been recently further improved since a dedicated technique for assembling large area Timepix detector arrays was introduced. Despite the fact that the sensitive area of Timepix detectors has been significantly increased, the pixel pitch is kept unchanged (55 microns). This value is much larger compared to widely used and popular X-ray imaging cameras utilizing scintillation crystals and CCD-based read-out. On the other hand, photon counting detectors provide steeper point-spread function. Therefore, with given effective pixel size of an acquired radiography, Timepix detectors provide higher spatial resolution than X-ray cameras with scintillation-based devices unless the image is affected by penumbral blur. In this paper we take an advance of steep PSF of photon counting detectors and test the possibility to improve the quality of computed tomography reconstruction using finer sampling of reconstructed voxel space. The achieved results are presented in comparison with data acquired under the same conditions using a commercially available state-of-the-art CCD X-ray camera.

Resolving Phase Ambiguities in the Calibration of Redundant Interferometric Arrays: Implications for Array Design

DTIC Science & Technology

2016-03-04

summary of the linear algebra involved. As we have seen, the RSC process begins with the interferometric phase measurement β, which due to wrapping will...mentary Divisors) in Section 2 and the following defi- nition of the matrix determinant. This definition is given in many linear algebra texts (see...principle solve for a particular solution of this system by arbitrarily setting two object phases (whose spatial frequencies are not co- linear ) and one

A Fast Method to Calculate the Spatial Impulse Response for 1-D Linear Ultrasonic Phased Array Transducers

PubMed Central

Zou, Cheng; Sun, Zhenguo; Cai, Dong; Muhammad, Salman; Zhang, Wenzeng; Chen, Qiang

2016-01-01

A method is developed to accurately determine the spatial impulse response at the specifically discretized observation points in the radiated field of 1-D linear ultrasonic phased array transducers with great efficiency. In contrast, the previously adopted solutions only optimize the calculation procedure for a single rectangular transducer and required approximation considerations or nonlinear calculation. In this research, an algorithm that follows an alternative approach to expedite the calculation of the spatial impulse response of a rectangular linear array is presented. The key assumption for this algorithm is that the transducer apertures are identical and linearly distributed on an infinite rigid plane baffled with the same pitch. Two points in the observation field, which have the same position relative to two transducer apertures, share the same spatial impulse response that contributed from corresponding transducer, respectively. The observation field is discretized specifically to meet the relationship of equality. The analytical expressions of the proposed algorithm, based on the specific selection of the observation points, are derived to remove redundant calculations. In order to measure the proposed methodology, the simulation results obtained from the proposed method and the classical summation method are compared. The outcomes demonstrate that the proposed strategy can speed up the calculation procedure since it accelerates the speed-up ratio which relies upon the number of discrete points and the number of the array transducers. This development will be valuable in the development of advanced and faster linear ultrasonic phased array systems. PMID:27834799

Using confidence intervals to evaluate the focus alignment of spectrograph detector arrays.

PubMed

Sawyer, Travis W; Hawkins, Kyle S; Damento, Michael

2017-06-20

High-resolution spectrographs extract detailed spectral information of a sample and are frequently used in astronomy, laser-induced breakdown spectroscopy, and Raman spectroscopy. These instruments employ dispersive elements such as prisms and diffraction gratings to spatially separate different wavelengths of light, which are then detected by a charge-coupled device (CCD) or complementary metal-oxide-semiconductor (CMOS) detector array. Precise alignment along the optical axis (focus position) of the detector array is critical to maximize the instrumental resolution; however, traditional approaches of scanning the detector through focus lack a quantitative measure of precision, limiting the repeatability and relying on one's experience. Here we propose a method to evaluate the focus alignment of spectrograph detector arrays by establishing confidence intervals to measure the alignment precision. We show that propagation of uncertainty can be used to estimate the variance in an alignment, thus providing a quantitative and repeatable means to evaluate the precision and confidence of an alignment. We test the approach by aligning the detector array of a prototype miniature echelle spectrograph. The results indicate that the procedure effectively quantifies alignment precision, enabling one to objectively determine when an alignment has reached an acceptable level. This quantitative approach also provides a foundation for further optimization, including automated alignment. Furthermore, the procedure introduced here can be extended to other alignment techniques that rely on numerically fitting data to a model, providing a general framework for evaluating the precision of alignment methods.

A 400 KHz line rate 2048 pixel modular SWIR linear array for earth observation applications

NASA Astrophysics Data System (ADS)

Anchlia, Ankur; Vinella, Rosa M.; Wouters, Kristof; Gielen, Daphne; Hooylaerts, Peter; Deroo, Pieter; Ruythooren, Wouter; van der Zanden, Koen; Vermeiren, Jan; Merken, Patrick

2015-10-01

In this paper, we report about a family of linear imaging FPAs sensitive in the [0.9 - 1.7um] band, developed for high speed applications such as LIDAR, wavelength references and OCT analyzers and also for earth observation applications. Fast linear FPAs can also be used in a wide variety of terrestrial applications, including high speed sorting, electro- and photo-luminesce and medical applications. The arrays are based on a modular ROIC design concept: modules of 512 pixels are stitched during fabrication to achieve 512, 1024 and 2048 pixel arrays. In principle, this concept can be extended to any multiple of 512 pixels, the limiting factor being the pixel yield of long InGaAs arrays and the CTE differences in the hybrid setup. Each 512-pixel module has its own on-chip digital sequencer, analog readout chain and 4 output buffers. This modular concept enables a long-linear array to run at a high line rate of 400 KHz irrespective of the array length, which limits the line rate in a traditional linear array. The pixel has a pitch of 12.5um. The detector frontend is based on CTIA (Capacitor Trans-impedance Amplifier), having 5 selectable integration capacitors giving full well from 62x103e- (gain0) to 40x106e- (gain4). An auto-zero circuit limits the detector bias non-uniformity to 5-10mV across broad intensity levels, limiting the input referred dark signal noise to 20e-rms for Tint=3ms at room temperature. An on-chip CDS that follows the CTIA facilitates removal of Reset/KTC noise, CTIA offsets and most of the 1/f noise. The measured noise of the ROIC is 35e-rms in gain0. At a master clock rate of 60MHz and a minimum integration time of 1.4us, the FPAs reach the highest line rate of 400 KHz.

Influence of elliptical structure on impinging-jet-array heat transfer performances

NASA Astrophysics Data System (ADS)

Arjocu, Simona C.; Liburdy, James A.

1997-11-01

A three-by-three square array of submerged, elliptic, impinging jets in water was used to study the heat transfer distribution in the cooling process of a constant heat flux surface. Tow jet aspect ratios were used, 2 and 3, both with the same hydraulic diameter. The array was tested at Reynolds numbers from 300 to 1500 and impinging distances of 1 to 5 hydraulic diameters. Thermochromic liquid crystals wee used to map the local heat transfer coefficient using a transient method, while the jet temperature was kept constant. The liquid crystal images were recorded through an optical fiber coupled with a CCD camera and a frame grabber and analyzed based on an RGB-temperature calibration technique. The results are reported relative to the unit cell that is used to delimitate the central jet. The heat transfer variation is shown to depend on the impingement distance and Reynolds number. The elliptic jets exhibit axis switching, jet column instability and jet swaying. All of these mechanisms affect the enhancement of the heat transfer rate and its distribution. The results are compared in terms of average and local heat transfer coefficients, for both major and minor planes for the two jet aspect ratios.

Geometric approach to the design of an imaging probe to evaluate the iridocorneal angle structures

NASA Astrophysics Data System (ADS)

Hong, Xun Jie Jeesmond; V. K., Shinoj; Murukeshan, V. M.; Baskaran, M.; Aung, Tin

2017-06-01

Photographic imaging methods allow the tracking of anatomical changes in the iridocorneal angle structures and the monitoring of treatment responses overtime. In this work, we aim to design an imaging probe to evaluate the iridocorneal angle structures using geometrical optics. We first perform an analytical analysis on light propagation from the anterior chamber of the eye to the exterior medium using Snell's law. This is followed by adopting a strategy to achieve uniform near field irradiance, by simplifying the complex non-rotational symmetric irradiance distribution of LEDs tilted at an angle. The optimization is based on the geometric design considerations of an angled circular ring array of 4 LEDs (or a 2 × 2 square LED array). The design equation give insights on variable parameters such as the illumination angle of the LEDs, ring array radius, viewing angle of the LEDs, and the working distance. A micro color CCD video camera that has sufficient resolution to resolve the iridocorneal angle structures at the required working distance is then chosen. The proposed design aspects fulfil the safety requirements recommended by the International Commission on Non-ionizing Radiation Protection.

Enhanced focus steering abilities of multi-element therapeutic arrays operating in nonlinear regimes

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

Yuldashev, P., E-mail: petr@acs366.phys.msu.ru; Ilyin, S.; Gavrilov, L.

2015-10-28

Steering abilities of a typical HIFU therapeutic array operated in linear and nonlinear regimes were compared using numerical simulation with the 3D Westervelt equation. The array included 256 elements of 1.2 MHz frequency and 6.6 mm diameter distributed in a quasi-random pattern over a spherical shell with a 130 mm aperture and a focal length of 120 mm. In the case of linear focusing, thermal effects are proportional to the intensity level and the criterion for safe array operation is that the intensity in the grating lobes should be less than 10% of the intensity in the main focus. Inmore » the case of nonlinear focusing, the heating effect is no longer proportional to intensity; therefore the heat deposition rate was chosen as the relevant metric, using the same 10% threshold for the secondary lobe in comparison with the focal maximum. When steering the focus, the same linearly predicted intensity level at the main focus was maintained by increasing the array power. Numerical simulations of the acoustic field were performed for nonlinear propagation both in water and in tissue. It was shown that for shock-forming conditions in the main focus, the steering range of safe electronic focusing is larger than that for linear propagation conditions. Nonlinear sonication regimes therefore can be used to enlarge tissue volumes that can be sonicated using electronic steering of the focus of HIFU arrays.« less

CCD Measurements and Linear Solution for WDS 02041-7115

NASA Astrophysics Data System (ADS)

Hensley, Hagan; Giles, Ava; Mayhue, Lance; Badami, Umar Ahmed; Tock, Kalée.

2018-01-01

The double star system WDS 02041-7115 or HJ 3483 was imaged using the Skynet Robotic Telescope Network on Jan 31 (Besselian date 2017.085). Using AstroImageJ, the secondary was measured to have a position angle of 263° and a separation of 7.6". Because the distance to the primary is known, along with the spectral classes and proper motions of both, we show that a gravitational relationship is not only unlikely, but mathematically impossible for these stars. Even if the secondary is at the same distance as the primary, its proper motion rela-tive to the primary would exceed its escape velocity. We also present a linear solution for the pair.

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.

Large Format CMOS-based Detectors for Diffraction Studies

NASA Astrophysics Data System (ADS)

Thompson, A. C.; Nix, J. C.; Achterkirchen, T. G.; Westbrook, E. M.

2013-03-01

Complementary Metal Oxide Semiconductor (CMOS) devices are rapidly replacing CCD devices in many commercial and medical applications. Recent developments in CMOS fabrication have improved their radiation hardness, device linearity, readout noise and thermal noise, making them suitable for x-ray crystallography detectors. Large-format (e.g. 10 cm × 15 cm) CMOS devices with a pixel size of 100 μm × 100 μm are now becoming available that can be butted together on three sides so that very large area detector can be made with no dead regions. Like CCD systems our CMOS systems use a GdOS:Tb scintillator plate to convert stopping x-rays into visible light which is then transferred with a fiber-optic plate to the sensitive surface of the CMOS sensor. The amount of light per x-ray on the sensor is much higher in the CMOS system than a CCD system because the fiber optic plate is only 3 mm thick while on a CCD system it is highly tapered and much longer. A CMOS sensor is an active pixel matrix such that every pixel is controlled and readout independently of all other pixels. This allows these devices to be readout while the sensor is collecting charge in all the other pixels. For x-ray diffraction detectors this is a major advantage since image frames can be collected continuously at up 20 Hz while the crystal is rotated. A complete diffraction dataset can be collected over five times faster than with CCD systems with lower radiation exposure to the crystal. In addition, since the data is taken fine-phi slice mode the 3D angular position of diffraction peaks is improved. We have developed a cooled 6 sensor CMOS detector with an active area of 28.2 × 29.5 cm with 100 μm × 100 μm pixels and a readout rate of 20 Hz. The detective quantum efficiency exceeds 60% over the range 8-12 keV. One, two and twelve sensor systems are also being developed for a variety of scientific applications. Since the sensors are butt able on three sides, even larger systems could be built at reasonable cost.

Development of a real-time, high-frequency ultrasound digital beamformer for high-frequency linear array transducers.

PubMed

Hu, Chang-Hong; Xu, Xiao-Chen; Cannata, Jonathan M; Yen, Jesse T; Shung, K Kirk

2006-02-01

A real-time digital beamformer for high-frequency (>20 MHz) linear ultrasonic arrays has been developed. The system can handle up to 64-element linear array transducers and excite 16 channels and receive simultaneously at 100 MHz sampling frequency with 8-bit precision. Radio frequency (RF) signals are digitized, delayed, and summed through a real-time digital beamformer, which is implemented using a field programmable gate array (FPGA). Using fractional delay filters, fine delays as small as 2 ns can be implemented. A frame rate of 30 frames per second is achieved. Wire phantom (20 microm tungsten) images were obtained and -6 dB axial and lateral widths were measured. The results showed that, using a 30 MHz, 48-element array with a pitch of 100 microm produced a -6 dB width of 68 microm in the axial and 370 microm in the lateral direction at 6.4 mm range. Images from an excised rabbit eye sample also were acquired, and fine anatomical structures, such as the cornea and lens, were resolved.

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

Rapid wide-field Mueller matrix polarimetry imaging based on four photoelastic modulators with no moving parts.

PubMed

Alali, Sanaz; Gribble, Adam; Vitkin, I Alex

2016-03-01

A new polarimetry method is demonstrated to image the entire Mueller matrix of a turbid sample using four photoelastic modulators (PEMs) and a charge coupled device (CCD) camera, with no moving parts. Accurate wide-field imaging is enabled with a field-programmable gate array (FPGA) optical gating technique and an evolutionary algorithm (EA) that optimizes imaging times. This technique accurately and rapidly measured the Mueller matrices of air, polarization elements, and turbid phantoms. The system should prove advantageous for Mueller matrix analysis of turbid samples (e.g., biological tissues) over large fields of view, in less than a second.

Mathematical construction and perturbation analysis of Zernike discrete orthogonal points.

PubMed

Shi, Zhenguang; Sui, Yongxin; Liu, Zhenyu; Peng, Ji; Yang, Huaijiang

2012-06-20

Zernike functions are orthogonal within the unit circle, but they are not over the discrete points such as CCD arrays or finite element grids. This will result in reconstruction errors for loss of orthogonality. By using roots of Legendre polynomials, a set of points within the unit circle can be constructed so that Zernike functions over the set are discretely orthogonal. Besides that, the location tolerances of the points are studied by perturbation analysis, and the requirements of the positioning precision are not very strict. Computer simulations show that this approach provides a very accurate wavefront reconstruction with the proposed sampling set.

Boundary-layer transition and global skin friction measurement with an oil-fringe imaging technique

NASA Technical Reports Server (NTRS)

Monson, Daryl J.; Mateer, George G.; Menter, Florian R.

1993-01-01

A new oil-fringe imaging system skin friction (FISF) technique to measure skin friction on wind tunnel models is presented. In the method used to demonstrate the technique, lines of oil are applied on surfaces that connect the intended sets of measurement points, and then a wind tunnel is run so that the oil thins and forms interference fringes that are spaced in proportion to local skin friction. After a run the fringe spacings are imaged with a CCD-array digital camera and measured on a computer. Skin friction and transition measurements on a two-dimensional wing are presented and compared with computational predictions.

Measurements of stratospheric composition using a star pointing spectrometer

NASA Technical Reports Server (NTRS)

Fish, Deb J.; Jones, Rod L.; Freshwater, Ray A.; Roscoe, Howard K.; Oldham, Derek J.

1994-01-01

Measurements of stratospheric composition have been made with a novel star-pointing spectrometer. The instrument consists of a telescope that focuses light from stars, planets, or the moon onto a spectrometer and two dimensional CCD array detector. Atmospheric absorptions can be measured, from which atmospheric columns of several gases can be determined. The instrument was deployed in Abisko, 69 deg N, during the European Arctic Stratospheric Ozone Experiment (EASOE). The instrument has the potential for measuring O3, OClO, NO2, and NO3. In this paper, a method for the retrieval of vertical columns is described, and some examples of ozone measurements given.

Cryogenic Optical Performance of the Cassini Composite InfraRed Spectrometer (CIRS) Flight Telescope

NASA Technical Reports Server (NTRS)

Losch, Patricia; Lyons, James J., III; Hagopian, John

1998-01-01

The CIRS half-meter diameter beryllium flight telescope's optical performance was tested at the instrument operating temperature of 170 Kelvin. The telescope components were designed at Goddard Space Flight Center (GSFC) but fabricated out of house and then assembled, aligned and tested upon receipt at GSFC. A 24 inch aperture cryogenic test facility utilizing a 1024 x 1024 CCD array was developed at GSFC specifically for this test. The telescope,s image quality (measured as encircled energy), boresight stability and focus stability were measured. The gold coated beryllium design exceeded the cold image performance requirement of 80% encircled energy within a 460 micron diameter circle.

A proof of the Woodward-Lawson sampling method for a finite linear array

NASA Technical Reports Server (NTRS)

Somers, Gary A.

1993-01-01

An extension of the continuous aperture Woodward-Lawson sampling theorem has been developed for a finite linear array of equidistant identical elements with arbitrary excitations. It is shown that by sampling the array factor at a finite number of specified points in the far field, the exact array factor over all space can be efficiently reconstructed in closed form. The specified sample points lie in real space and hence are measurable provided that the interelement spacing is greater than approximately one half of a wavelength. This paper provides insight as to why the length parameter used in the sampling formulas for discrete arrays is larger than the physical span of the lattice points in contrast with the continuous aperture case where the length parameter is precisely the physical aperture length.

Design and calibration of a six-axis MEMS sensor array for use in scoliosis correction surgery

NASA Astrophysics Data System (ADS)

Benfield, David; Yue, Shichao; Lou, Edmond; Moussa, Walied A.

2014-08-01

A six-axis sensor array has been developed to quantify the 3D force and moment loads applied in scoliosis correction surgery. Initially this device was developed to be applied during scoliosis correction surgery and augmented onto existing surgical instrumentation, however, use as a general load sensor is also feasible. The development has included the design, microfabrication, deployment and calibration of a sensor array. The sensor array consists of four membrane devices, each containing piezoresistive sensing elements, generating a total of 16 differential voltage outputs. The calibration procedure has made use of a custom built load application frame, which allows quantified forces and moments to be applied and compared to the outputs from the sensor array. Linear or non-linear calibration equations are generated to convert the voltage outputs from the sensor array back into 3D force and moment information for display or analysis.

Radar Resource Management in a Dense Target Environment

DTIC Science & Technology

2014-03-01

problem faced by networked MFRs . While relaxing our assumptions concerning information gain presents numerous challenges worth exploring, future research...linear programming MFR multifunction phased array radar MILP mixed integer linear programming NATO North Atlantic Treaty Organization PDF probability...1: INTRODUCTION Multifunction phased array radars ( MFRs ) are capable of performing various tasks in rapid succession. The performance of target search

Position sensor for linear synchronous motors employing halbach arrays

DOEpatents

Post, Richard Freeman

2014-12-23

A position sensor suitable for use in linear synchronous motor (LSM) drive systems employing Halbach arrays to create their magnetic fields is described. The system has several advantages over previously employed ones, especially in its simplicity and its freedom from being affected by weather conditions, accumulated dirt, or electrical interference from the LSM system itself.

Rotary encoding device

NASA Technical Reports Server (NTRS)

Leviton, Douglas B. (Inventor)

1993-01-01

A device for position encoding of a rotating shaft in which a polygonal mirror having a number of facets is mounted to the shaft and a light beam is directed towards the facets is presented. The facets of the polygonal mirror reflect the light beam such that a light spot is created on a linear array detector. An analog-to-digital converter is connected to the linear array detector for reading the position of the spot on the linear array detector. A microprocessor with memory is connected to the analog-to-digital converter to hold and manipulate the data provided by the analog-to-digital converter on the position of the spot and to compute the position of the shaft based upon the data from the analog-to-digital converter.

A permanent magnet tubular linear generator for wave energy conversion

NASA Astrophysics Data System (ADS)

Yu, Haitao; Liu, Chunyuan; Yuan, Bang; Hu, Minqiang; Huang, Lei; Zhou, Shigui

2012-04-01

A novel three-phase permanent magnet tubular linear generator (PMTLG) with Halbach array is proposed for the sea wave energy conversion. Non-linear axi-symmetrical finite element method (FEM) is implemented to calculate the magnetic fields along air-gap for different Halbach arrays of PMTLGs. The PMTLG characteristics are analyzed and the simulation results are validated by the experiment. An assistant tooth is implemented to greatly minimize the end and cogging effects which cause the oscillatory detent force.

Resolving phase ambiguities in the calibration of redundant interferometric arrays: implications for array design

DTIC Science & Technology

2015-11-30

matrix determinant. This definition is given in many linear algebra texts (see e.g. Bretscher (2001)). Definition 3.1 : Suppose we have an n-by-n...Processing, 2, 767 Blanchard P., Greenaway A., Anderton R., Appleby R., 1996, J. Opt. Soc. Am. A, 13, 1593 Bretscher O., 2001, Linear Algebra with...frequencies are not co- linear ) and one piston phase. This particular solution will then differ from the true solution by a phase ramp in the Fourier

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.

Performance Characterization of the Chromospheric Lyman-Alpha Spectro-Polarimeter (CLASP) CCD Cameras

NASA Technical Reports Server (NTRS)

Joiner, Reyann; Kobayashi, Ken; Winebarger, Amy; Champey, Patrick

2014-01-01

The Chromospheric Lyman-Alpha Spectro-Polarimeter (CLASP) is a sounding rocket instrument currently being developed by NASA's Marshall Space Flight Center (MSFC), the National Astronomical Observatory of Japan (NAOJ), and other partners. The goal of this instrument is to observe and detect the Hanle effect in the scattered Lyman-Alpha UV (121.6nm) light emitted by the Sun's chromosphere. The polarized spectrum imaged by the CCD cameras will capture information about the local magnetic field, allowing for measurements of magnetic strength and structure. In order to make accurate measurements of this effect, the performance characteristics of the three on- board charge-coupled devices (CCDs) must meet certain requirements. These characteristics include: quantum efficiency, gain, dark current, read noise, and linearity. Each of these must meet predetermined requirements in order to achieve satisfactory performance for the mission. The cameras must be able to operate with a gain of 2.0+/- 0.5 e--/DN, a read noise level less than 25e-, a dark current level which is less than 10e-/pixel/s, and a residual non- linearity of less than 1%. Determining these characteristics involves performing a series of tests with each of the cameras in a high vacuum environment. Here we present the methods and results of each of these performance tests for the CLASP flight cameras.

Demonstration of a vectorial optical field generator with adaptive close loop control.

PubMed

Chen, Jian; Kong, Lingjiang; Zhan, Qiwen

2017-12-01

We experimentally demonstrate a vectorial optical field generator (VOF-Gen) with an adaptive close loop control. The close loop control capability is illustrated with the calibration of polarization modulation of the system. To calibrate the polarization ratio modulation, we generate 45° linearly polarized beam and make it propagate through a linear analyzer whose transmission axis is orthogonal to the incident beam. For the retardation calibration, circularly polarized beam is employed and a circular polarization analyzer with the opposite chirality is placed in front of the CCD as the detector. In both cases, the close loop control automatically changes the value of the corresponding calibration parameters in the pre-set ranges to generate the phase patterns applied to the spatial light modulators and records the intensity distribution of the output beam by the CCD camera. The optimized calibration parameters are determined corresponding to the minimum total intensity in each case. Several typical kinds of vectorial optical beams are created with and without the obtained calibration parameters, and the full Stokes parameter measurements are carried out to quantitatively analyze the polarization distribution of the generated beams. The comparisons among these results clearly show that the obtained calibration parameters could remarkably improve the accuracy of the polarization modulation of the VOF-Gen, especially for generating elliptically polarized beam with large ellipticity, indicating the significance of the presented close loop in enhancing the performance of the VOF-Gen.

Nonlinear plasmonic behavior of nanohole arrays in thin gold films for imaging lipids

NASA Astrophysics Data System (ADS)

Subramaniyam, Nagarajan; Shah, Ali; Dreser, Christoph; Isomäki, Antti; Fleischer, Monika; Sopanen, Markku

2018-06-01

We demonstrate linear and nonlinear plasmonic behaviors of periodic nanohole arrays in thin gold (Au) films with varying periodicities. As expected, the linear optical transmission spectra of the nanohole arrays show a red-shift of the resonance wavelength and Wood's anomaly with increasing hole spacing. The optical transmission and electric near-field intensity distribution of the nanohole arrays are simulated using the finite element method. The nonlinear plasmonic behavior of the nanohole arrays is studied by using picosecond pulsed excitation at near-infrared wavelengths. The characteristic nonlinear signals indicating two-photon excited luminescence (TPEL), sum frequency generation, second harmonic generation, and four-wave mixing (FWM) are observed. A maximum FWM/TPEL signal intensity ratio is achieved for nanohole arrays with a periodicity of 500 nm. Furthermore, the significant FWM signal intensity and contrast compared to the background were harnessed to demonstrate the ability of surface-enhanced coherent anti-Stokes Raman scattering to visualize low concentrations of lipids deposited on the nanohole array with a periodicity of 500 nm.

A beamforming study for implementation of vibro-acoustography with a 1.75-D array transducer.

PubMed

Urban, Matthew W; Chalek, Carl; Haider, Bruno; Thomenius, Kai E; Fatemi, Mostafa; Alizad, Azra

2013-03-01

Vibro-acoustography (VA) is an ultrasound-based imaging modality that uses radiation force produced by two cofocused ultrasound beams separated by a small frequency difference, Δf, to vibrate tissue at Δf. An acoustic field is created by the object vibration and measured with a nearby hydrophone. This method has recently been implemented on a clinical ultrasound system using 1-D linear-array transducers. In this article, we discuss VA beamforming and image formation using a 1.75-D array transducer. A 1.75-D array transducer has several rows of elements in the elevation direction which can be controlled independently for focusing. The advantage of the 1.75-D array over a 1-D linear-array transducer is that multiple rows of elements can be used for improving elevation focus for imaging formation. Six configurations for subaperture design for the two ultrasound beams necessary for VA imaging were analyzed. The point-spread functions for these different configurations were evaluated using a numerical simulation model. Four of these configurations were then chosen for experimental evaluation with a needle hydrophone as well as for scanning two phantoms. Images were formed by scanning a urethane breast phantom and an ex vivo human prostate. VA imaging using a 1.75-D array transducer offers several advantages over scanning with a linear-array transducer, including improved image resolution and contrast resulting from better elevation focusing of the imaging point-spread function.

A Beamforming Study for Implementation of Vibro-acoustography with a 1.75D Array Transducer

PubMed Central

Urban, Matthew W.; Chalek, Carl; Haider, Bruno; Thomenius, Kai E.; Fatemi, Mostafa; Alizad, Azra

2013-01-01

Vibro-acoustography (VA) is an ultrasound-based imaging modality that uses radiation force produced by two cofocused ultrasound beams separated by a small frequency difference, Δf, to vibrate tissue at Δf. An acoustic field is created by the object vibration and measured with a nearby hydrophone. This method has recently been implemented on a clinical ultrasound system using one-dimensional (1D) linear array transducers. In this article, we discuss VA beamforming and image formation using a 1.75D array transducer. A 1.75D array transducer has several rows of elements in the elevation direction which can be controlled independently for focusing. The advantage of the 1.75D array over a 1D linear array transducer is that multiple rows of elements can be used for improving elevation focus for imaging formation. Six configurations for subaperture design for the two ultrasound beams necessary for VA imaging were analyzed. The point-spread functions for these different configurations were evaluated using a numerical simulation model. Four of these configurations were then chosen for experimental evaluation with a needle hydrophone as well as for scanning two phantoms. Images were formed by scanning a urethane breast phantom and an ex vivo human prostate. VA imaging using a 1.75D array transducer offers several advantages over scanning with a linear array transducer including improved image resolution and contrast due to better elevation focusing of the imaging point-spread function. PMID:23475919

Validity and reliability of rectus femoris ultrasound measurements: Comparison of curved-array and linear-array transducers.

PubMed

Hammond, Kendra; Mampilly, Jobby; Laghi, Franco A; Goyal, Amit; Collins, Eileen G; McBurney, Conor; Jubran, Amal; Tobin, Martin J

2014-01-01

Muscle-mass loss augers increased morbidity and mortality in critically ill patients. Muscle-mass loss can be assessed by wide linear-array ultrasound transducers connected to cumbersome, expensive console units. Whether cheaper, hand-carried units equipped with curved-array transducers can be used as alternatives is unknown. Accordingly, our primary aim was to investigate in 15 nondisabled subjects the validity of measurements of rectus femoris cross-sectional area by using a curved-array transducer against a linear-array transducer-the reference-standard technique. In these subjects, we also determined the reliability of measurements obtained by a novice operator versus measurements obtained by an experienced operator. Lastly, the relationship between quadriceps strength and rectus area recorded by two experienced operators with a curved-array transducer was assessed in 17 patients with chronic obstructive pulmonary disease (COPD). In nondisabled subjects, the rectus cross-sectional area measured with the curved-array transducer by the novice and experienced operators was valid (intraclass correlation coefficient [ICC]: 0.98, typical percentage error [%TE]: 3.7%) and reliable (ICC: 0.79, %TE: 9.7%). In the subjects with COPD, both reliability (ICC: 0.99) and repeatability (%TE: 7.6% and 9.8%) were high. Rectus area was related to quadriceps strength in COPD for both experienced operators (coefficient of determination: 0.67 and 0.70). In conclusion, measurements of rectus femoris cross-sectional area recorded with a curved-array transducer connected to a hand-carried unit are valid, reliable, and reproducible, leading us to contend that this technique is suitable for cross-sectional and longitudinal studies.

Simulation and Testing of a Linear Array of Modified Four-Square Feed Antennas for the Tianlai Cylindrical Radio Telescope

NASA Astrophysics Data System (ADS)

Cianciara, Aleksander J.; Anderson, Christopher J.; Chen, Xuelei; Chen, Zhiping; Geng, Jingchao; Li, Jixia; Liu, Chao; Liu, Tao; Lu, Wing; Peterson, Jeffrey B.; Shi, Huli; Steffel, Catherine N.; Stebbins, Albert; Stucky, Thomas; Sun, Shijie; Timbie, Peter T.; Wang, Yougang; Wu, Fengquan; Zhang, Juyong

A wide bandwidth, dual polarized, modified four-square antenna is presented as a feed antenna for radio astronomical measurements. A linear array of these antennas is used as a line-feed for cylindrical reflectors for Tianlai, a radio interferometer designed for 21cm intensity mapping. Simulations of the feed antenna beam patterns and scattering parameters are compared to experimental results at multiple frequencies across the 650-1420MHz range. Simulations of the beam patterns of the combined feed array/reflector are presented as well.

The Pariser-Parr-Pople model for trans-polyenes. I. Ab initio and semiempirical study of the bond alternation in trans-butadiene

NASA Astrophysics Data System (ADS)

Förner, Wolfgang

1992-03-01

Ab initio investigations of the bond alternation in butadiene are presented. The atomic basis sets applied range from minimal to split valence plus polarization quality. With the latter one the Hartree-Fock limit for the bond alternation is reached. Correlation is considered on Møller-Plesset many-body perturbation theory of second order (MP2), linear coupled cluster doubles (L-CCD) and coupled cluster doubles (CCD) level. For the smaller basis sets it is shown that for the bond alternation π-π correlations are essential while the effects of σ-σ and σ-π correlations are, though large, nearly independent of bond alternation. On MP2 level the variation of σ-π correlation with bond alternation is surprisingly large. This is discussed as an artefact of MP2. Comparative Su-Schrieffer-Heeger (SSH) and Pariser-Parr-Pople (PPP) calculations show that these models in their usual parametrizations cannot reproduce the ab initio results.

A high-resolution line sensor-based photostereometric system for measuring jaw movements in 6 degrees of freedom.

PubMed

Hayashi, T; Kurokawa, M; Miyakawa, M; Aizawa, T; Kanaki, A; Saitoh, A; Ishioka, K

1994-01-01

Photostereometry has widely been applied to the measurement of mandibular movements in 6 degrees of freedom. In order to improve the accuracy of this measurement, we developed a system utilizing small LEDs mounted on the jaws in redundant numbers and a 5000 pixel linear charge-coupled device (CCD) as a photo-sensor. A total of eight LEDs are mounted on the jaws, in two sets of four, by means of connecting facebows, each weighing approximately 55 g. The position of the LEDs are detected in three-dimensions by two sets of three CCD cameras, located bilaterally. The position and orientation of the mandible are estimated from the positions of all LEDs measured in the sense of least-squares, thereby effectively reducing the measurement errors. The static overall accuracy at all tooth and condylar points was considered to lie within 0.19 and 0.34 mm, respectively, from various accuracy verification tests.

Influence of varus/valgus positioning of the Nanos® and Metha® short-stemmed prostheses on stress shielding of metaphyseal bone.

PubMed

Brinkmann, V; Radetzki, F; Gutteck, N; Delank, S; Zeh, A

2017-03-01

The aim of this study was to analyze bone remodeling around the Nanos® (Smith & Nephew) and Metha® (Aesculap AG) implants as a function of varus/valgus stem positioning. In 75 patients with diagnosed coxarthrosis, either Nanos® (n= 51) or Metha® (n= 24) prostheses were implanted. Digital assessment of plain radiographs immediately, 97 days, and 381 days after THA showed no clinically-relevant migration, angulation, or change in offset and center of rotation. The DEXA scans showed significant BMD changes in Gruen zones 1 (-12.8%), 2 (-3.3%), 6 (+6.4%), and 7(-7.8%)(t-test). The pre/postoperative CCD for the Nanos® was 129°/ 135° and for the Metha® 131°/ 127°. Linear regression analysis showed no prediction for BMD by postoperative CCD or stem type. In conclusion, there was no clinically-relevant influence on proximal femur BMD according to varus/valgus implantation of the Nanos® or Metha® prostheses.

Calibrators measurement system for headlamp tester of motor vehicle base on machine vision

NASA Astrophysics Data System (ADS)

Pan, Yue; Zhang, Fan; Xu, Xi-ping; Zheng, Zhe

2014-09-01

With the development of photoelectric detection technology, machine vision has a wider use in the field of industry. The paper mainly introduces auto lamps tester calibrator measuring system, of which CCD image sampling system is the core. Also, it shows the measuring principle of optical axial angle and light intensity, and proves the linear relationship between calibrator's facula illumination and image plane illumination. The paper provides an important specification of CCD imaging system. Image processing by MATLAB can get flare's geometric midpoint and average gray level. By fitting the statistics via the method of the least square, we can get regression equation of illumination and gray level. It analyzes the error of experimental result of measurement system, and gives the standard uncertainty of synthesis and the resource of optical axial angle. Optical axial angle's average measuring accuracy is controlled within 40''. The whole testing process uses digital means instead of artificial factors, which has higher accuracy, more repeatability and better mentality than any other measuring systems.

Optimization of technological procedure for amygdalin isolation from plum seeds (Pruni domesticae semen)

PubMed Central

Savic, Ivan M.; Nikolic, Vesna D.; Savic-Gajic, Ivana M.; Nikolic, Ljubisa B.; Ibric, Svetlana R.; Gajic, Dragoljub G.

2015-01-01

The process of amygdalin extraction from plum seeds was optimized using central composite design (CCD) and multilayer perceptron (MLP). The effect of time, ethanol concentration, solid-to-liquid ratio, and temperature on the amygdalin content in the extracts was estimated using both mathematical models. The MLP 4-3-1 with exponential function in hidden layer and linear function in output layer was used for describing the extraction process. MLP model was more superior compared with CCD model due to better prediction ability. According to MLP model, the suggested optimal conditions are: time of 120 min, 100% (v/v) ethanol, solid-to liquid ratio of 1:25 (m/v) and temperature of 34.4°C. The predicted value of amygdalin content in the dried extract (25.42 g per 100 g) at these conditions was experimentally confirmed (25.30 g per 100 g of dried extract). Amygdalin (>90%) was isolated from the complex extraction mixture and structurally characterized by FT-IR, UV, and MS methods. PMID:25972881

CCAM: A novel millimeter-wave instrument using a close-packed TES bolometer array

NASA Astrophysics Data System (ADS)

Lau, Judy M.

This thesis describes CCAM, an instrument designed to map the Cosmic Microwave Background (CMB), and also presents some of the initial measurements made with CCAM on the Atacama Cosmology Telescope (ACT). CCAM uses a CCD-like camera of millimeter-wave TES bolometers. It employs new detector technology, read-out electronics, cold re-imaging optics, and cryogenics to obtain high sensitivity CMB anisotropy measurements. The free-standing 8×32 close-packed array of pop- up TES detectors is the first of its kind to observe the sky at 145 GHz. We present the design of the receiver including the antireflection coated silicon lens re-imaging system, construction and optimization of the pulse tube/ sorption refrigerator cryogenic system, as well as the technology developed to integrate eight 1×32 TES columns and accompanying read-out electronics in to an array of 256 millimeter-wave detectors into a focal plane area of 3.5 cm 2. The performance of the detectors and optics prior to deployment at the ACT site in Chile are reported as well as preliminary performance results of the instrument when optically paired with the ACT telescope in the summer of 2007. Here, we also report on the feasibility of the TES detector array to measure polarization when coupled to a rotating birefringent sapphire half wave plate and wire-grid polarizer.

Adding polarimetric imaging to depth map using improved light field camera 2.0 structure

NASA Astrophysics Data System (ADS)

Zhang, Xuanzhe; Yang, Yi; Du, Shaojun; Cao, Yu

2017-06-01

Polarization imaging plays an important role in various fields, especially for skylight navigation and target identification, whose imaging system is always required to be designed with high resolution, broad band, and single-lens structure. This paper describe such a imaging system based on light field 2.0 camera structure, which can calculate the polarization state and depth distance from reference plane for every objet point within a single shot. This structure, including a modified main lens, a multi-quadrants Polaroid, a honeycomb-liked micro lens array, and a high resolution CCD, is equal to an "eyes array", with 3 or more polarization imaging "glasses" in front of each "eye". Therefore, depth can be calculated by matching the relative offset of corresponding patch on neighboring "eyes", while polarization state by its relative intensity difference, and their resolution will be approximately equal to each other. An application on navigation under clear sky shows that this method has a high accuracy and strong robustness.

Grating array systems having a plurality of gratings operative in a coherently additive mode and methods for making such grating array systems

DOEpatents

Kessler, Terrance J [Mendon, NY; Bunkenburg, Joachim [Victor, NY; Huang, Hu [Pittsford, NY

2007-02-13

A plurality of gratings (G1, G2) are arranged together with a wavefront sensor, actuators, and feedback system to align the gratings in such a manner, that they operate like a single, large, monolithic grating. Sub-wavelength-scale movements in the mechanical mounting, due to environmental influences, are monitored by an interferometer (28), and compensated by precision actuators (16, 18, 20) that maintain the coherently additive mode. The actuators define the grating plane, and are positioned in response to the wavefronts from the gratings and a reference flat, thus producing the interferogram that contains the alignment information. Movement of the actuators is also in response to a diffraction-limited spot on the CCD (36) to which light diffracted from the gratings is focused. The actuator geometry is implemented to take advantage of the compensating nature of the degrees of freedom between gratings, reducing the number of necessary control variables.

Modeling the spectral response for the soft X-ray imager onboard the ASTRO-H satellite

NASA Astrophysics Data System (ADS)

Inoue, Shota; Hayashida, Kiyoshi; Katada, Shuhei; Nakajima, Hiroshi; Nagino, Ryo; Anabuki, Naohisa; Tsunemi, Hiroshi; Tsuru, Takeshi Go; Tanaka, Takaaki; Uchida, Hiroyuki; Nobukawa, Masayoshi; Nobukawa, Kumiko Kawabata; Washino, Ryosaku; Mori, Koji; Isoda, Eri; Sakata, Miho; Kohmura, Takayoshi; Tamasawa, Koki; Tanno, Shoma; Yoshino, Yuma; Konno, Takahiro; Ueda, Shutaro; ASTRO-H/SXI Team

2016-09-01

The ASTRO-H satellite is the 6th Japanese X-ray astronomical observatory to be launched in early 2016. The satellite carries four kinds of detectors, and one of them is an X-ray CCD camera, the soft X-ray imager (SXI), installed on the focal plane of an X-ray telescope. The SXI contains four CCD chips, each with an imaging area of 31 mm × 31 mm , arrayed in mosaic, covering the field-of-view of 38‧ ×38‧ , the widest ever flown in orbit. The CCDs are a P-channel back-illuminated (BI) type with a depletion layer thickness of 200 μ m . We operate the CCDs in a photon counting mode in which the position and energy of each photon are measured in the energy band of 0.4-12 keV. To evaluate the X-ray spectra obtained with the SXI, an accurate calibration of its response function is essential. For this purpose, we performed calibration experiments at Kyoto and Photon Factory of KEK, each with different X-ray sources with various X-ray energies. We fit the obtained spectra with 5 components; primary peak, secondary peak, constant tail, Si escape and Si fluorescence, and then model their energy dependence using physics-based or empirical formulae. Since this is the first adoption of P-channel BI-type CCDs on an X-ray astronomical satellite, we need to take special care on the constant tail component which is originated in partial charge collection. It is found that we need to assume a trapping layer at the incident surface of the CCD and implement it in the response model. In addition, the Si fluorescence component of the SXI response is significantly weak, compared with those of front-illuminated type CCDs.

Experimental Evaluation of Optically Polished Aluminum Panels on the Deep Space Network's 34 Meter Antenna

NASA Technical Reports Server (NTRS)

Vilnrotter, V.

2011-01-01

The potential development of large aperture ground?based "photon bucket" optical receivers for deep space communications has received considerable attention recently. One approach currently under investigation is to polish the aluminum reflector panels of 34?meter microwave antennas to high reflectance, and accept the relatively large spotsize generated by state of?the?art polished aluminum panels. Theoretical analyses of receiving antenna pointing, temporal synchronization and data detection have been addressed in previous papers. Here we describe the experimental effort currently underway at the Deep Space Network (DSN) Goldstone Communications Complex in California, to test and verify these concepts in a realistic operational environment. Two polished aluminum panels (a standard DSN panel polished to high reflectance, and a custom designed aluminum panel with much better surface quality) have been mounted on the 34 meter research antenna at Deep?Space Station 13 (DSS?13), and a remotely controlled CCD camera with a large CCD sensor in a weather?proof container has been installed next to the subreflector, pointed directly at the custom polished panel. The point?spread function (PSF) generated by the Vertex polished panel has been determined to be smaller than the sensor of the CCD camera, hence a detailed picture of the PSF can be obtained every few seconds, and the sensor array data processed to determine the center of the intensity distribution. In addition to estimating the center coordinates, expected communications performance can also been evaluated with the recorded data. The results of preliminary pointing experiments with the Vertex polished panel receiver using the planet Jupiter to simulate the PSF generated by a deep?space optical transmitter are presented and discussed in this paper.

Development of the focal plane PNCCD camera system for the X-ray space telescope eROSITA

NASA Astrophysics Data System (ADS)

Meidinger, Norbert; Andritschke, Robert; Ebermayer, Stefanie; Elbs, Johannes; Hälker, Olaf; Hartmann, Robert; Herrmann, Sven; Kimmel, Nils; Schächner, Gabriele; Schopper, Florian; Soltau, Heike; Strüder, Lothar; Weidenspointner, Georg

2010-12-01

A so-called PNCCD, a special type of CCD, was developed twenty years ago as focal plane detector for the XMM-Newton X-ray astronomy mission of the European Space Agency ESA. Based on this detector concept and taking into account the experience of almost ten years of operation in space, a new X-ray CCD type was designed by the ‘MPI semiconductor laboratory’ for an upcoming X-ray space telescope, called eROSITA (extended Roentgen survey with an imaging telescope array). This space telescope will be equipped with seven X-ray mirror systems of Wolter-I type and seven CCD cameras, placed in their foci. The instrumentation permits the exploration of the X-ray universe in the energy band from 0.3 up to 10 keV by spectroscopic measurements with a time resolution of 50 ms for a full image comprising 384×384 pixels. Main scientific goals are an all-sky survey and investigation of the mysterious ‘Dark Energy’. The eROSITA space telescope, which is developed under the responsibility of the ‘Max-Planck-Institute for extraterrestrial physics’, is a scientific payload on the new Russian satellite ‘Spectrum-Roentgen-Gamma’ (SRG). The mission is already approved by the responsible Russian and German space agencies. After launch in 2012 the destination of the satellite is Lagrange point L2. The planned observational program takes about seven years. We describe the design of the eROSITA camera system and present important test results achieved recently with the eROSITA prototype PNCCD detector. This includes a comparison of the eROSITA detector with the XMM-Newton detector.

A spatial capture-recapture model to estimate fish survival and location from linear continuous monitoring arrays

USGS Publications Warehouse

Raabe, Joshua K.; Gardner, Beth; Hightower, Joseph E.

2013-01-01

We developed a spatial capture–recapture model to evaluate survival and activity centres (i.e., mean locations) of tagged individuals detected along a linear array. Our spatially explicit version of the Cormack–Jolly–Seber model, analyzed using a Bayesian framework, correlates movement between periods and can incorporate environmental or other covariates. We demonstrate the model using 2010 data for anadromous American shad (Alosa sapidissima) tagged with passive integrated transponders (PIT) at a weir near the mouth of a North Carolina river and passively monitored with an upstream array of PIT antennas. The river channel constrained migrations, resulting in linear, one-dimensional encounter histories that included both weir captures and antenna detections. Individual activity centres in a given time period were a function of the individual’s previous estimated location and the river conditions (i.e., gage height). Model results indicate high within-river spawning mortality (mean weekly survival = 0.80) and more extensive movements during elevated river conditions. This model is applicable for any linear array (e.g., rivers, shorelines, and corridors), opening new opportunities to study demographic parameters, movement or migration, and habitat use.

Phased Array Theory and Technology

DTIC Science & Technology

1981-07-01

Generalized Array Coordinates 2. Linear, Planar and Circular Art -ays 3. Periodic fwo Dimensional ^rras 4. Grating Lobe Lattices 5. 1’llenienl...formal and low profile antennas, antennas for limited sector coverage, and wide- band array feeds. To aid designers, there is an attempt to give ...ol Vol. 2, Elliott gives convenient formulas lor the directivity of Imear dipole arrays, and derives an especially simple form tor arrays

Performance bounds for modal analysis using sparse linear arrays

NASA Astrophysics Data System (ADS)

Li, Yuanxin; Pezeshki, Ali; Scharf, Louis L.; Chi, Yuejie

2017-05-01

We study the performance of modal analysis using sparse linear arrays (SLAs) such as nested and co-prime arrays, in both first-order and second-order measurement models. We treat SLAs as constructed from a subset of sensors in a dense uniform linear array (ULA), and characterize the performance loss of SLAs with respect to the ULA due to using much fewer sensors. In particular, we claim that, provided the same aperture, in order to achieve comparable performance in terms of Cramér-Rao bound (CRB) for modal analysis, SLAs require more snapshots, of which the number is about the number of snapshots used by ULA times the compression ratio in the number of sensors. This is shown analytically for the case with one undamped mode, as well as empirically via extensive numerical experiments for more complex scenarios. Moreover, the misspecified CRB proposed by Richmond and Horowitz is also studied, where SLAs suffer more performance loss than their ULA counterpart.

Rotary encoding device with polygonal reflector and centroid detection

NASA Technical Reports Server (NTRS)

Leviton, Douglas B. (Inventor)

1994-01-01

A device for positioning encoding of a rotating shaft in which a polygonal mirror having a number of facets is mounted to the shaft and a light beam is directed towards the facets. The facets of the polygonal mirror reflect the light beam such that a light spot is created on a linear array detector. An analog-to-digital converter is connected to the linear array detector for reading the position of the spot on the spots on the linear array detector. A microprocessor with memory is connected to the analog-to-digital converter to hold and manipulate the data provided by the analog-to-digital converter on the position of the spot and to compute the position of the shaft based upon the data from the analog-to-digital converter.

Fiber optical assembly for fluorescence spectrometry

DOEpatents

Carpenter, II, Robert W.; Rubenstein, Richard; Piltch, Martin; Gray, Perry

2010-12-07

A system for analyzing a sample for the presence of an analyte in a sample. The system includes a sample holder for containing the sample; an excitation source, such as a laser, and at least one linear array radially disposed about the sample holder. Radiation from the excitation source is directed to the sample, and the radiation induces fluorescent light in the sample. Each linear array includes a plurality of fused silica optical fibers that receive the fluorescent light and transmits a fluorescent light signal from the first end to an optical end port of the linear array. An end port assembly having a photo-detector is optically coupled to the optical end port. The photo-detector detects the fluorescent light signal and converts the fluorescent light signal into an electrical signal.

Solar XUV Imaging and Non-dispersive Spectroscopy for Solar-C Enabled by Scientific CMOS APS Arrays

NASA Astrophysics Data System (ADS)

Stern, Robert A.; Lemen, J. R.; Shing, L.; Janesick, J.; Tower, J.

2009-05-01

Monolithic CMOS Advanced Pixel Sensor (APS) arrays are showing great promise as eventual replacements for the current workhorse of solar physics focal planes, the scientific CCD. CMOS APS devices have individually addressable pixels, increased radiation tolerance compared to CCDs, and require lower clock voltages, and thus lower power. However, commercially available CMOS chips, while suitable for use with intensifiers or fluorescent coatings, are generally not optimized for direct detection of EUV and X-ray photons. A high performance scientific CMOS array designed for these wavelengths will have significant new capabilities compared to CCDs, including the ability to read out small regions of the solar disk at high (sub sec) cadence, count single X-ray photons with Fano-limited energy resolution, and even operate at room temperature with good noise performance. Such capabilities will be crucial for future solar X-ray and EUV missions such as Solar-C. Sarnoff Corporation has developed scientific grade, monolithic CMOS arrays for X-ray imaging and photon counting. One prototype device, the "minimal" array, has 8 um pixels, is 15 to 25 um thick, is fabricated on high-resistivity ( 10 to 20 kohm-cm) Si wafers, and can be back-illuminated. These characteristics yield high quantum efficiency and high spatial resolution with minimal charge sharing among pixels, making it ideal for the detection of keV X-rays. When used with digital correlated double sampling, the array has demonstrated noise performance as low as 2 e, allowing single photon counting of X-rays over a range of temperatures. We report test results for this device in X-rays, and discuss the implications for future solar space missions.

A High-Speed, Event-Driven, Active Pixel Sensor Readout for Photon-Counting Microchannel Plate Detectors

NASA Technical Reports Server (NTRS)

Kimble, Randy A.; Pain, B.; Norton, T. J.; Haas, P.; Fisher, Richard R. (Technical Monitor)

2001-01-01

Silicon array readouts for microchannel plate intensifiers offer several attractive features. In this class of detector, the electron cloud output of the MCP intensifier is converted to visible light by a phosphor; that light is then fiber-optically coupled to the silicon array. In photon-counting mode, the resulting light splashes on the silicon array are recognized and centroided to fractional pixel accuracy by off-chip electronics. This process can result in very high (MCP-limited) spatial resolution for the readout while operating at a modest MCP gain (desirable for dynamic range and long term stability). The principal limitation of intensified CCD systems of this type is their severely limited local dynamic range, as accurate photon counting is achieved only if there are not overlapping event splashes within the frame time of the device. This problem can be ameliorated somewhat by processing events only in pre-selected windows of interest or by using an addressable charge injection device (CID) for the readout array. We are currently pursuing the development of an intriguing alternative readout concept based on using an event-driven CMOS Active Pixel Sensor. APS technology permits the incorporation of discriminator circuitry within each pixel. When coupled with suitable CMOS logic outside the array area, the discriminator circuitry can be used to trigger the readout of small sub-array windows only when and where an event splash has been detected, completely eliminating the local dynamic range problem, while achieving a high global count rate capability and maintaining high spatial resolution. We elaborate on this concept and present our progress toward implementing an event-driven APS readout.

Fast correction approach for wavefront sensorless adaptive optics based on a linear phase diversity technique.

PubMed

Yue, Dan; Nie, Haitao; Li, Ye; Ying, Changsheng

2018-03-01

Wavefront sensorless (WFSless) adaptive optics (AO) systems have been widely studied in recent years. To reach optimum results, such systems require an efficient correction method. This paper presents a fast wavefront correction approach for a WFSless AO system mainly based on the linear phase diversity (PD) technique. The fast closed-loop control algorithm is set up based on the linear relationship between the drive voltage of the deformable mirror (DM) and the far-field images of the system, which is obtained through the linear PD algorithm combined with the influence function of the DM. A large number of phase screens under different turbulence strengths are simulated to test the performance of the proposed method. The numerical simulation results show that the method has fast convergence rate and strong correction ability, a few correction times can achieve good correction results, and can effectively improve the imaging quality of the system while needing fewer measurements of CCD data.

Acoustic emission linear pulse holography

DOEpatents

Collins, H.D.; Busse, L.J.; Lemon, D.K.

1983-10-25

This device relates to the concept of and means for performing Acoustic Emission Linear Pulse Holography, which combines the advantages of linear holographic imaging and Acoustic Emission into a single non-destructive inspection system. This unique system produces a chronological, linear holographic image of a flaw by utilizing the acoustic energy emitted during crack growth. The innovation is the concept of utilizing the crack-generated acoustic emission energy to generate a chronological series of images of a growing crack by applying linear, pulse holographic processing to the acoustic emission data. The process is implemented by placing on a structure an array of piezoelectric sensors (typically 16 or 32 of them) near the defect location. A reference sensor is placed between the defect and the array.

The image acquisition system design of floor grinder

NASA Astrophysics Data System (ADS)

Wang, Yang-jiang; Liu, Wei; Liu, Hui-qin

2018-01-01

Based on linear CCD, high resolution image real-time acquisition system serves as designing a set of image acquisition system for floor grinder through the calculation of optical imaging system. The entire image acquisition system can collect images of ground before and after the work of the floor grinder, and the data is transmitted through the Bluetooth system to the computer and compared to realize real-time monitoring of its working condition. The system provides technical support for the design of unmanned ground grinders.

Innovation ability and innovation spirit in photoelectric comprehensive experiment teaching

NASA Astrophysics Data System (ADS)

Wang, Dexing; Zhang, Yang; Wang, Xiaofeng; Zhang, Xiaojun; Zhang, Tao; Sun, Peng

2017-08-01

The traditional experimental teaching methods have some shortcomings in the training the student innovation ability. In order to improve the student practical ability in the photoelectric technology, in this paper new experimental teaching modes are tried and reformed for cultivating the innovative ability of students in the linear CCD experiment. The photoelectric experiment systems are independently designed and completed by students. Compared with the traditional experimental teaching methods, this new methods have a great role in the development of the ability of creative thinking.

Transients in the synchronization of asymmetrically coupled oscillator arrays

NASA Astrophysics Data System (ADS)

Cantos, C. E.; Hammond, D. K.; Veerman, J. J. P.

2016-09-01

We consider the transient behavior of a large linear array of coupled linear damped harmonic oscillators following perturbation of a single element. Our work is motivated by modeling the behavior of flocks of autonomous vehicles. We first state a number of conjectures that allow us to derive an explicit characterization of the transients, within a certain parameter regime Ω. As corollaries we show that minimizing the transients requires considering non-symmetric coupling, and that within Ω the computed linear growth in N of the transients is independent of (reasonable) boundary conditions.

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.

Kalman filter-based tracking of moving objects using linear ultrasonic sensor array for road vehicles

NASA Astrophysics Data System (ADS)

Li, Shengbo Eben; Li, Guofa; Yu, Jiaying; Liu, Chang; Cheng, Bo; Wang, Jianqiang; Li, Keqiang

2018-01-01

Detection and tracking of objects in the side-near-field has attracted much attention for the development of advanced driver assistance systems. This paper presents a cost-effective approach to track moving objects around vehicles using linearly arrayed ultrasonic sensors. To understand the detection characteristics of a single sensor, an empirical detection model was developed considering the shapes and surface materials of various detected objects. Eight sensors were arrayed linearly to expand the detection range for further application in traffic environment recognition. Two types of tracking algorithms, including an Extended Kalman filter (EKF) and an Unscented Kalman filter (UKF), for the sensor array were designed for dynamic object tracking. The ultrasonic sensor array was designed to have two types of fire sequences: mutual firing or serial firing. The effectiveness of the designed algorithms were verified in two typical driving scenarios: passing intersections with traffic sign poles or street lights, and overtaking another vehicle. Experimental results showed that both EKF and UKF had more precise tracking position and smaller RMSE (root mean square error) than a traditional triangular positioning method. The effectiveness also encourages the application of cost-effective ultrasonic sensors in the near-field environment perception in autonomous driving systems.

Broadband implementation of coprime linear microphone arrays for direction of arrival estimation.

PubMed

Bush, Dane; Xiang, Ning

2015-07-01

Coprime arrays represent a form of sparse sensing which can achieve narrow beams using relatively few elements, exceeding the spatial Nyquist sampling limit. The purpose of this paper is to expand on and experimentally validate coprime array theory in an acoustic implementation. Two nested sparse uniform linear subarrays with coprime number of elements ( M and N) each produce grating lobes that overlap with one another completely in just one direction. When the subarray outputs are combined it is possible to retain the shared beam while mostly canceling the other superfluous grating lobes. In this way a small number of microphones ( N+M-1) creates a narrow beam at higher frequencies, comparable to a densely populated uniform linear array of MN microphones. In this work beampatterns are simulated for a range of single frequencies, as well as bands of frequencies. Narrowband experimental beampatterns are shown to correspond with simulated results even at frequencies other than the arrays design frequency. Narrowband side lobe locations are shown to correspond to the theoretical values. Side lobes in the directional pattern are mitigated by increasing bandwidth of analyzed signals. Direction of arrival estimation is also implemented for two simultaneous noise sources in a free field condition.

250 kA compact linear transformer driver for wire array z-pinch loads

NASA Astrophysics Data System (ADS)

Bott, S. C.; Haas, D. M.; Madden, R. E.; Ueda, U.; Eshaq, Y.; Collins, G., IV; Gunasekera, K.; Mariscal, D.; Peebles, J.; Beg, F. N.; Mazarakis, M.; Struve, K.; Sharpe, R.

2011-05-01

We present the application of a short rise (˜150ns) 250 kA linear transformer driver (LTD) to wire array z-pinch loads for the first time. The generator is a modification of a previous driver in which a new conical power feed provides a low inductance coupling to wire loads. Performance of the new design using both short circuit and plasma loads is presented and discussed. The final design delivers ˜200kA to a wire array load which is in good agreement with SCREAMER calculations using a simplified representative circuit. Example results demonstrate successful experiments using cylindrical, conical, and inverse wire arrays as well as previously published work on x-pinch loads.

Cytosolic and Plastoglobule-targeted Carotenoid Dioxygenases from Crocus sativus Are Both Involved in β-Ionone Release*

PubMed Central

Rubio, Angela; Rambla, José Luís; Santaella, Marcella; Gómez, M. Dolores; Orzaez, Diego; Granell, Antonio; Gómez-Gómez, Lourdes

2008-01-01

Saffron, the processed stigma of Crocus sativus, is characterized by the presence of several apocarotenoids that contribute to the color, flavor, and aroma of the spice. However, little is known about the synthesis of aroma compounds during the development of the C. sativus stigma. The developing stigma is nearly odorless, but before and at anthesis, the aromatic compound β-ionone becomes the principal norisoprenoid volatile in the stigma. In this study, four carotenoid cleavage dioxygenase (CCD) genes, CsCCD1a, CsCCD1b, CsCCD4a, and CsCCD4b, were isolated from C. sativus. Expression analysis showed that CsCCD1a was constitutively expressed, CsCCD1b was unique to the stigma tissue, but only CsCCD4a and -b had expression patterns consistent with the highest levels of β-carotene and emission of β-ionone derived during the stigma development. The CsCCD4 enzymes were localized in plastids and more specifically were present in the plastoglobules. The enzymatic activities of CsCCD1a, CsCCD1b, and CsCCD4 enzymes were determined by Escherichia coli expression, and subsequent analysis of the volatile products was generated by GC/MS. The four CCDs fell in two phylogenetically divergent dioxygenase classes, but all could cleave β-carotene at the 9,10(9′,10′) positions to yield β-ionone. The data obtained suggest that all four C. sativus CCD enzymes may contribute in different ways to the production of β-ionone. In addition, the location and precise timing of β-ionone synthesis, together with its known activity as a fragrance and insect attractant, suggest that this volatile may have a role in Crocus pollination. PMID:18611853

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.

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.

One dimensional wavefront distortion sensor comprising a lens array system

DOEpatents

Neal, Daniel R.; Michie, Robert B.

1996-01-01

A 1-dimensional sensor for measuring wavefront distortion of a light beam as a function of time and spatial position includes a lens system which incorporates a linear array of lenses, and a detector system which incorporates a linear array of light detectors positioned from the lens system so that light passing through any of the lenses is focused on at least one of the light detectors. The 1-dimensional sensor determines the slope of the wavefront by location of the detectors illuminated by the light. The 1 dimensional sensor has much greater bandwidth that 2 dimensional systems.

One dimensional wavefront distortion sensor comprising a lens array system

DOEpatents

Neal, D.R.; Michie, R.B.

1996-02-20

A 1-dimensional sensor for measuring wavefront distortion of a light beam as a function of time and spatial position includes a lens system which incorporates a linear array of lenses, and a detector system which incorporates a linear array of light detectors positioned from the lens system so that light passing through any of the lenses is focused on at least one of the light detectors. The 1-dimensional sensor determines the slope of the wavefront by location of the detectors illuminated by the light. The 1 dimensional sensor has much greater bandwidth that 2 dimensional systems. 8 figs.

A class of parallel algorithms for computation of the manipulator inertia matrix

NASA Technical Reports Server (NTRS)

Fijany, Amir; Bejczy, Antal K.

1989-01-01

Parallel and parallel/pipeline algorithms for computation of the manipulator inertia matrix are presented. An algorithm based on composite rigid-body spatial inertia method, which provides better features for parallelization, is used for the computation of the inertia matrix. Two parallel algorithms are developed which achieve the time lower bound in computation. Also described is the mapping of these algorithms with topological variation on a two-dimensional processor array, with nearest-neighbor connection, and with cardinality variation on a linear processor array. An efficient parallel/pipeline algorithm for the linear array was also developed, but at significantly higher efficiency.

Detection of pointing errors with CMOS-based camera in intersatellite optical communications

NASA Astrophysics Data System (ADS)

Yu, Si-yuan; Ma, Jing; Tan, Li-ying

2005-01-01

For very high data rates, intersatellite optical communications hold a potential performance edge over microwave communications. Acquisition and Tracking problem is critical because of the narrow transmit beam. A single array detector in some systems performs both spatial acquisition and tracking functions to detect pointing errors, so both wide field of view and high update rate is required. The past systems tend to employ CCD-based camera with complex readout arrangements, but the additional complexity reduces the applicability of the array based tracking concept. With the development of CMOS array, CMOS-based cameras can employ the single array detector concept. The area of interest feature of the CMOS-based camera allows a PAT system to specify portion of the array. The maximum allowed frame rate increases as the size of the area of interest decreases under certain conditions. A commercially available CMOS camera with 105 fps @ 640×480 is employed in our PAT simulation system, in which only part pixels are used in fact. Beams angle varying in the field of view can be detected after getting across a Cassegrain telescope and an optical focus system. Spot pixel values (8 bits per pixel) reading out from CMOS are transmitted to a DSP subsystem via IEEE 1394 bus, and pointing errors can be computed by the centroid equation. It was shown in test that: (1) 500 fps @ 100×100 is available in acquisition when the field of view is 1mrad; (2)3k fps @ 10×10 is available in tracking when the field of view is 0.1mrad.

High-Speed Linear Raman Spectroscopy for Instability Analysis of a Bluff Body Flame

NASA Technical Reports Server (NTRS)

Kojima, Jun; Fischer, David

2013-01-01

We report a high-speed laser diagnostics technique based on point-wise linear Raman spectroscopy for measuring the frequency content of a CH4-air premixed flame stabilized behind a circular bluff body. The technique, which primarily employs a Nd:YLF pulsed laser and a fast image-intensified CCD camera, successfully measures the time evolution of scalar parameters (N2, O2, CH4, and H2O) in the vortex-induced flame instability at a data rate of 1 kHz. Oscillation of the V-shaped flame front is quantified through frequency analysis of the combustion species data and their correlations. This technique promises to be a useful diagnostics tool for combustion instability studies.

Phase-controllable spin wave generation in iron garnet by linearly polarized light pulses

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

Yoshimine, Isao; Iida, Ryugo; Shimura, Tsutomu

A phase-controlled spin wave was non-thermally generated in bismuth-doped rare-earth iron garnet by linearly polarized light pulses. We controlled the initial phase of the spin wave continuously within a range of 180° by changing the polarization azimuth of the excitation light. The azimuth dependences of the initial phase and amplitude of the spin wave were attributed to a combination of the inverse Cotton-Mouton effect and photoinduced magnetic anisotropy. Temporally and spatially resolved spin wave propagation was observed with a CCD camera, and the waveform was in good agreement with calculations. A nonlinear effect of the spin excitation was observed formore » excitation fluences higher than 100 mJ/cm{sup 2}.« less

A strand-passage conformation of DNA gyrase is required to allow the bacterial toxin, CcdB, to access its binding site

PubMed Central

Smith, Andrew B.; Maxwell, Anthony

2006-01-01

DNA gyrase is the only topoisomerase able to introduce negative supercoils into DNA. Absent in humans, gyrase is a successful target for antibacterial drugs. However, increasing drug resistance is a serious problem and new agents are urgently needed. The naturally-produced Escherichia coli toxin CcdB has been shown to target gyrase by what is predicted to be a novel mechanism. CcdB has been previously shown to stabilize the gyrase ‘cleavage complex’, but it has not been shown to inhibit the catalytic reactions of gyrase. We present data showing that CcdB does indeed inhibit the catalytic reactions of gyrase by stabilization of the cleavage complex and that the GyrA C-terminal DNA-wrapping domain and the GyrB N-terminal ATPase domain are dispensable for CcdB's action. We further investigate the role of specific GyrA residues in the action of CcdB by site-directed mutagenesis; these data corroborate a model for CcdB action based on a recent crystal structure of a CcdB–GyrA fragment complex. From this work, we are now able to present a model for CcdB action that explains all previous observations relating to CcdB–gyrase interaction. CcdB action requires a conformation of gyrase that is only revealed when DNA strand passage is taking place. PMID:16963775

A strand-passage conformation of DNA gyrase is required to allow the bacterial toxin, CcdB, to access its binding site.

PubMed

Smith, Andrew B; Maxwell, Anthony

2006-01-01

DNA gyrase is the only topoisomerase able to introduce negative supercoils into DNA. Absent in humans, gyrase is a successful target for antibacterial drugs. However, increasing drug resistance is a serious problem and new agents are urgently needed. The naturally-produced Escherichia coli toxin CcdB has been shown to target gyrase by what is predicted to be a novel mechanism. CcdB has been previously shown to stabilize the gyrase 'cleavage complex', but it has not been shown to inhibit the catalytic reactions of gyrase. We present data showing that CcdB does indeed inhibit the catalytic reactions of gyrase by stabilization of the cleavage complex and that the GyrA C-terminal DNA-wrapping domain and the GyrB N-terminal ATPase domain are dispensable for CcdB's action. We further investigate the role of specific GyrA residues in the action of CcdB by site-directed mutagenesis; these data corroborate a model for CcdB action based on a recent crystal structure of a CcdB-GyrA fragment complex. From this work, we are now able to present a model for CcdB action that explains all previous observations relating to CcdB-gyrase interaction. CcdB action requires a conformation of gyrase that is only revealed when DNA strand passage is taking place.

Petunia hybrida CAROTENOID CLEAVAGE DIOXYGENASE7 is involved in the production of negative and positive branching signals in petunia.

PubMed

Drummond, Revel S M; Martínez-Sánchez, N Marcela; Janssen, Bart J; Templeton, Kerry R; Simons, Joanne L; Quinn, Brian D; Karunairetnam, Sakuntala; Snowden, Kimberley C

2009-12-01

One of the key factors that defines plant form is the regulation of when and where branches develop. The diversity of form observed in nature results, in part, from variation in the regulation of branching between species. Two CAROTENOID CLEAVAGE DIOXYGENASE (CCD) genes, CCD7 and CCD8, are required for the production of a branch-suppressing plant hormone. Here, we report that the decreased apical dominance3 (dad3) mutant of petunia (Petunia hybrida) results from the mutation of the PhCCD7 gene and has a less severe branching phenotype than mutation of PhCCD8 (dad1). An analysis of the expression of this gene in wild-type, mutant, and grafted petunia suggests that in petunia, CCD7 and CCD8 are coordinately regulated. In contrast to observations in Arabidopsis (Arabidopsis thaliana), ccd7ccd8 double mutants in petunia show an additive phenotype. An analysis using dad3 or dad1 mutant scions grafted to wild-type rootstocks showed that when these plants produce adventitious mutant roots, branching is increased above that seen in plants where the mutant roots are removed. The results presented here indicate that mutation of either CCD7 or CCD8 in petunia results in both the loss of an inhibitor of branching and an increase in a promoter of branching.

Petunia hybrida CAROTENOID CLEAVAGE DIOXYGENASE7 Is Involved in the Production of Negative and Positive Branching Signals in Petunia1[W][OA

PubMed Central

Drummond, Revel S.M.; Martínez-Sánchez, N. Marcela; Janssen, Bart J.; Templeton, Kerry R.; Simons, Joanne L.; Quinn, Brian D.; Karunairetnam, Sakuntala; Snowden, Kimberley C.

2009-01-01

One of the key factors that defines plant form is the regulation of when and where branches develop. The diversity of form observed in nature results, in part, from variation in the regulation of branching between species. Two CAROTENOID CLEAVAGE DIOXYGENASE (CCD) genes, CCD7 and CCD8, are required for the production of a branch-suppressing plant hormone. Here, we report that the decreased apical dominance3 (dad3) mutant of petunia (Petunia hybrida) results from the mutation of the PhCCD7 gene and has a less severe branching phenotype than mutation of PhCCD8 (dad1). An analysis of the expression of this gene in wild-type, mutant, and grafted petunia suggests that in petunia, CCD7 and CCD8 are coordinately regulated. In contrast to observations in Arabidopsis (Arabidopsis thaliana), ccd7ccd8 double mutants in petunia show an additive phenotype. An analysis using dad3 or dad1 mutant scions grafted to wild-type rootstocks showed that when these plants produce adventitious mutant roots, branching is increased above that seen in plants where the mutant roots are removed. The results presented here indicate that mutation of either CCD7 or CCD8 in petunia results in both the loss of an inhibitor of branching and an increase in a promoter of branching. PMID:19846541

Performance and characterization of new micromachined high-frequency linear arrays.

PubMed

Lukacs, Marc; Yin, Jianhua; Pang, Guofeng; Garcia, Richard C; Cherin, Emmanuel; Williams, Ross; Mehi, Jim; Foster, F Stuart

2006-10-01

A new approach for fabricating high frequency (> 20 MHz) linear array transducers, based on laser micromachining, has been developed. A 30 MHz, 64-element, 74-microm pitch, linear array design is presented. The performance of the device is demonstrated by comparing electrical and acoustic measurements with analytical, equivalent circuit, and finite-element analysis (FEA) simulations. All FEA results for array performance have been generated using one global set of material parameters. Each fabricated array has been integrated onto a flex circuit for ease of handling, and the flex has been integrated onto a custom printed circuit board test card for ease of testing. For a fully assembled array, with an acoustic lens, the center frequency was 28.7 MHz with a one-way -3 dB and -6 dB bandwidth of 59% and 83%, respectively, and a -20 dB pulse width of -99 ns. The per-element peak acoustic power, for a +/- 30 V single cycle pulse, measured at the 10 mm focal length of the lens was 590 kPa with a -6 dB directivity span of about 30 degrees. The worst-case total cross talk of the combined array and flex assembly is for nearest neighboring elements and was measured to have an average level -40 dB across the -6 dB bandwidth of the device. Any significant deviation from simulation can be explained through limitations in apparatus calibration and in device packaging.

Geometric analysis and restitution of digital multispectral scanner data arrays

NASA Technical Reports Server (NTRS)

Baker, J. R.; Mikhail, E. M.

1975-01-01

An investigation was conducted to define causes of geometric defects within digital multispectral scanner (MSS) data arrays, to analyze the resulting geometric errors, and to investigate restitution methods to correct or reduce these errors. Geometric transformation relationships for scanned data, from which collinearity equations may be derived, served as the basis of parametric methods of analysis and restitution of MSS digital data arrays. The linearization of these collinearity equations is presented. Algorithms considered for use in analysis and restitution included the MSS collinearity equations, piecewise polynomials based on linearized collinearity equations, and nonparametric algorithms. A proposed system for geometric analysis and restitution of MSS digital data arrays was used to evaluate these algorithms, utilizing actual MSS data arrays. It was shown that collinearity equations and nonparametric algorithms both yield acceptable results, but nonparametric algorithms possess definite advantages in computational efficiency. Piecewise polynomials were found to yield inferior results.

Reduction of Cross-Reactive Carbohydrate Determinants in Plant Foodstuff: Elucidation of Clinical Relevance and Implications for Allergy Diagnosis

PubMed Central

Brehler, Randolf; von Schaewen, Antje

2011-01-01

Background A longstanding debate in allergy is whether or not specific immunoglobulin-E antibodies (sIgE), recognizing cross-reactive carbohydrate determinants (CCD), are able to elicit clinical symptoms. In pollen and food allergy, ≥20% of patients display in-vitro CCD reactivity based on presence of α1,3-fucose and/or β1,2-xylose residues on N-glycans of plant (xylose/fucose) and insect (fucose) glycoproteins. Because the allergenicity of tomato glycoallergen Lyc e 2 was ascribed to N-glycan chains alone, this study aimed at evaluating clinical relevance of CCD-reduced foodstuff in patients with carbohydrate-specific IgE (CCD-sIgE). Methodology/Principal Findings Tomato and/or potato plants with stable reduction of Lyc e 2 (tomato) or CCD formation in general were obtained via RNA interference, and gene-silencing was confirmed by immunoblot analyses. Two different CCD-positive patient groups were compared: one with tomato and/or potato food allergy and another with hymenoptera-venom allergy (the latter to distinguish between CCD- and peptide-specific reactions in the food-allergic group). Non-allergic and CCD-negative food-allergic patients served as controls for immunoblot, basophil activation, and ImmunoCAP analyses. Basophil activation tests (BAT) revealed that Lyc e 2 is no key player among other tomato (glyco)allergens. CCD-positive patients showed decreased (re)activity with CCD-reduced foodstuff, most obvious in the hymenoptera venom-allergic but less in the food-allergic group, suggesting that in-vivo reactivity is primarily based on peptide- and not CCD-sIgE. Peptide epitopes remained unaffected in CCD-reduced plants, because CCD-negative patient sera showed reactivity similar to wild-type. In-house-made ImmunoCAPs, applied to investigate feasibility in routine diagnosis, confirmed BAT results at the sIgE level. Conclusions/Significance CCD-positive hymenoptera venom-allergic patients (control group) showed basophil activation despite no allergic symptoms towards tomato and potato. Therefore, this proof-of-principle study demonstrates feasibility of CCD-reduced foodstuff to minimize ‘false-positive results’ in routine serum tests. Despite confirming low clinical relevance of CCD antibodies, we identified one patient with ambiguous in-vitro results, indicating need for further component-resolved diagnosis. PMID:21423762

Linear array measurements of enhanced dynamic wedge and treatment planning system (TPS) calculation for 15 MV photon beam and comparison with electronic portal imaging device (EPID) measurements.

PubMed

Petrovic, Borislava; Grzadziel, Aleksandra; Rutonjski, Laza; Slosarek, Krzysztof

2010-09-01

Enhanced dynamic wedges (EDW) are known to increase drastically the radiation therapy treatment efficiency. This paper has the aim to compare linear array measurements of EDW with the calculations of treatment planning system (TPS) and the electronic portal imaging device (EPID) for 15 MV photon energy. The range of different field sizes and wedge angles (for 15 MV photon beam) were measured by the linear chamber array CA 24 in Blue water phantom. The measurement conditions were applied to the calculations of the commercial treatment planning system XIO CMS v.4.2.0 using convolution algorithm. EPID measurements were done on EPID-focus distance of 100 cm, and beam parameters being the same as for CA24 measurements. Both depth doses and profiles were measured. EDW linear array measurements of profiles to XIO CMS TPS calculation differ around 0.5%. Profiles in non-wedged direction and open field profiles practically do not differ. Percentage depth doses (PDDs) for all EDW measurements show the difference of not more than 0.2%, while the open field PDD is almost the same as EDW PDD. Wedge factors for 60 deg wedge angle were also examined, and the difference is up to 4%. EPID to linear array differs up to 5%. The implementation of EDW in radiation therapy treatments provides clinicians with an effective tool for the conformal radiotherapy treatment planning. If modelling of EDW beam in TPS is done correctly, a very good agreement between measurements and calculation is obtained, but EPID cannot be used for reference measurements.

Physical interpretation and development of ultrasonic nondestructive evaluation techniques applied to the quantitative characterization of textile composite materials

NASA Technical Reports Server (NTRS)

Miller, James G.

1994-01-01

In this Progress Report, we describe our continuing research activities concerning the development and implementation of advanced ultrasonic nondestructive evaluation methods applied to the inspection and characterization of complex composite structures. We explore the feasibility of implementing medical linear array imaging technology as a viable ultrasonic-based nondestructive evaluation method to inspect and characterize complex materials. As an initial step toward the application of linear array imaging technology to the interrogation of a wide range of complex composite structures, we present images obtained using an unmodified medical ultrasonic imaging system of two epoxy-bonded aluminum plate specimens, each with intentionally disbonded regions. These images are compared with corresponding conventional ultrasonic contact transducer measurements in order to assess whether these images can detect disbonded regions and provide information regarding the nature of the disbonded region. We present a description of a standoff/delay fixture which has been designed, constructed, and implemented on a Hewlett-Packard SONOS 1500 medical imaging system. This standoff/delay fixture, when attached to a 7.5 MHz linear array probe, greatly enhances our ability to interrogate flat plate specimens. The final section of this Progress Report describes a woven composite plate specimen that has been specially machined to include intentional flaws. This woven composite specimen will allow us to assess the feasibility of applying linear array imaging technology to the inspection and characterization of complex textile composite materials. We anticipate the results of this on-going investigation may provide a step toward the development of a rapid, real-time, and portable method of ultrasonic inspection and characterization based on linear array technology.

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.

VUV Testing of Science Cameras at MSFC: QE Measurement of the CLASP Flight Cameras

NASA Technical Reports Server (NTRS)

Champey, Patrick; Kobayashi, Ken; Winebarger, Amy; Cirtain, Jonathan; Hyde, David; Robertson, Bryan; Beabout, Brent; Beabout, Dyana; Stewart, Mike

2015-01-01

The NASA Marshall Space Flight Center (MSFC) has developed a science camera suitable for sub-orbital missions for observations in the UV, EUV and soft X-ray. Six cameras were built and tested for the Chromospheric Lyman-Alpha Spectro-Polarimeter (CLASP), a joint National Astronomical Observatory of Japan (NAOJ) and MSFC sounding rocket mission. The CLASP camera design includes a frame-transfer e2v CCD57-10 512x512 detector, dual channel analog readout electronics and an internally mounted cold block. At the flight operating temperature of -20 C, the CLASP cameras achieved the low-noise performance requirements (less than or equal to 25 e- read noise and greater than or equal to 10 e-/sec/pix dark current), in addition to maintaining a stable gain of approximately equal to 2.0 e-/DN. The e2v CCD57-10 detectors were coated with Lumogen-E to improve quantum efficiency (QE) at the Lyman- wavelength. A vacuum ultra-violet (VUV) monochromator and a NIST calibrated photodiode were employed to measure the QE of each camera. Four flight-like cameras were tested in a high-vacuum chamber, which was configured to operate several tests intended to verify the QE, gain, read noise, dark current and residual non-linearity of the CCD. We present and discuss the QE measurements performed on the CLASP cameras. We also discuss the high-vacuum system outfitted for testing of UV and EUV science cameras at MSFC.

Time-saving design of experiment protocol for optimization of LC-MS data processing in metabolomic approaches.

PubMed

Zheng, Hong; Clausen, Morten Rahr; Dalsgaard, Trine Kastrup; Mortensen, Grith; Bertram, Hanne Christine

2013-08-06

We describe a time-saving protocol for the processing of LC-MS-based metabolomics data by optimizing parameter settings in XCMS and threshold settings for removing noisy and low-intensity peaks using design of experiment (DoE) approaches including Plackett-Burman design (PBD) for screening and central composite design (CCD) for optimization. A reliability index, which is based on evaluation of the linear response to a dilution series, was used as a parameter for the assessment of data quality. After identifying the significant parameters in the XCMS software by PBD, CCD was applied to determine their values by maximizing the reliability and group indexes. Optimal settings by DoE resulted in improvements of 19.4% and 54.7% in the reliability index for a standard mixture and human urine, respectively, as compared with the default setting, and a total of 38 h was required to complete the optimization. Moreover, threshold settings were optimized by using CCD for further improvement. The approach combining optimal parameter setting and the threshold method improved the reliability index about 9.5 times for a standards mixture and 14.5 times for human urine data, which required a total of 41 h. Validation results also showed improvements in the reliability index of about 5-7 times even for urine samples from different subjects. It is concluded that the proposed methodology can be used as a time-saving approach for improving the processing of LC-MS-based metabolomics data.

Feasibility of Using Linearly Polarized Rotating Birdcage Transmitters and Close-Fitting Receive Arrays in MRI to Reduce SAR in the Vicinity of Deep Brain Simulation Implants

PubMed Central

Golestanirad, Laleh; Keil, Boris; Angelone, Leonardo M.; Bonmassar, Giorgio; Mareyam, Azma; Wald, Lawrence L.

2016-01-01

Purpose MRI of patients with deep brain stimulation (DBS) implants is strictly limited due to safety concerns, including high levels of local specific absorption rate (SAR) of radiofrequency (RF) fields near the implant and related RF-induced heating. This study demonstrates the feasibility of using a rotating linearly polarized birdcage transmitter and a 32-channel close-fit receive array to significantly reduce local SAR in MRI of DBS patients. Methods Electromagnetic simulations and phantom experiments were performed with generic DBS lead geometries and implantation paths. The technique was based on mechanically rotating a linear birdcage transmitter to align its zero electric-field region with the implant while using a close-fit receive array to significantly increase signal to noise ratio of the images. Results It was found that the zero electric-field region of the transmitter is thick enough at 1.5 Tesla to encompass DBS lead trajectories with wire segments that were up to 30 degrees out of plane, as well as leads with looped segments. Moreover, SAR reduction was not sensitive to tissue properties, and insertion of a close-fit 32-channel receive array did not degrade the SAR reduction performance. Conclusion The ensemble of rotating linear birdcage and 32-channel close-fit receive array introduces a promising technology for future improvement of imaging in patients with DBS implants. PMID:27059266

Means for phase locking the outputs of a surface emitting laser diode array

NASA Technical Reports Server (NTRS)

Lesh, James R. (Inventor)

1987-01-01

An array of diode lasers, either a two-dimensional array of surface emitting lasers, or a linear array of stripe lasers, is phase locked by a diode laser through a hologram which focuses the output of the diode laser into a set of distinct, spatially separated beams, each one focused onto the back facet of a separate diode laser of the array. The outputs of the diode lasers thus form an emitted coherent beam out of the front of the array.

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.

Freely Drifting Swallow Float Array: May 1987 Trip Report

DTIC Science & Technology

1988-05-01

co’-4 v-4~ I00 I.U I6z oJy 2ZIWO Is Y)L Figur X.4x ca C)CD U) Lo Cc r(no _0 I IC VV ~.N L) Figue X. 4bD !K U.n a1 u iP K ( o 0) 1 1(: I.,L Il 4, U ch...La. Pw ~’(rh I y- El - tD Efp KL Cr) -- - If MaIKuOOPzlwO FigreXr)b. -~ jtn x4 a(I-~)WIo u- _0 c ca CO _ -4 I’a) Fic’uX15~ 4-0C es ~ -J-L p -S.7e -f-i

Pushing the Boundaries of X-ray Grating Spectroscopy in a Suborbital Rocket

NASA Technical Reports Server (NTRS)

McEntaffer, Randall L.; DeRoo, Casey; Schultz, Ted; Zhang, William W.; Murray, Neil J.; O'Dell, Stephen; Cash, Webster

2013-01-01

Developments in grating spectroscopy are paramount for meeting the soft X-ray science goals of future NASA X-ray Observatories. While developments in the laboratory setting have verified the technical feasibility of using off-plane reflection gratings to reach this goal, flight heritage is a key step in the development process toward large missions. To this end we have developed a design for a suborbital rocket payload employing an Off-Plane X-ray Grating Spectrometer. This spectrometer utilizes slumped glass Wolter-1 optics, an array of gratings, and a CCD camera. We discuss the unique capabilities of this design, the expected performance, the science return, and the perceived impact to future missions.

MINERVA: A Dedicated Observatory for Detection of Nearby Low-Mass Exoplanets

NASA Astrophysics Data System (ADS)

McCrady, Nate; Johnson, John; Wright, Jason; Wittenmyer, Robert A.; Blake, Cullen; Swift, Jonathan; Eastman, Jason D.; Plavchan, Peter; Riddle, Reed L.; Muirhead, Philip Steven; Bottom, Michael; Zhao, Ming; Beatty, Thomas G.

2015-01-01

Detection of low-mass planets around GKM stars requires sub-meter-per-second radial velocity precision. Stellar noise sources (starspots, oscillations, and granulation) necessitate high cadence observations. MINERVA is a dedicated observatory for velocimetric detection of low mass exoplanets orbiting nearby stars. Our array of four robotic 0.7-meter PlaneWave telescopes feeds a purpose-built, temperature-stabilized, iodine cell spectrometer from Callaghan Innovation. We will monitor bright, sun-like stars within 100 pc every clear night from Whipple Observatory on Mt Hopkins, Arizona. Each telescope is also equipped with an Andor CCD for followup photometry and education use. Commissioning is underway on the site and science observations will begin in early 2015.

Single-Shot Spectrally Resolved UV Rayleigh Scattering Measurements in High Speed Flow

NASA Technical Reports Server (NTRS)

Seasholtz, Richard G.

1996-01-01

A single-shot UV molecular Rayleigh scattering technique to measure velocity in high speed flow is described. The beam from an injection-seeded, frequency quadrupled Nd:YAG laser (266 nm) is focused to a line in a free air jet with velocities up to Mach 1.3. Rayleigh scattered light is imaged through a planar mirror Fabry-Perot interferometer onto a Charged Coupled Device (CCD) array detector. Some laser light is also simultaneously imaged through the Fabry-Perot to provide a frequency reference. Two velocity measurements are obtained from each image. Multiple-pulse data are also given. The Rayleigh scattering velocity data show good agreement with velocities calculated from isentropic flow relations.

Infrared Astronomy

NASA Astrophysics Data System (ADS)

Grygar, J.

2018-04-01

Although infrared radiation was described by W. Herschel already in 1800, technical problems delayed its use in astronomy for 160 years. After the invention of a sensitive bolometer and semiconducting CCD arrays for very wide infrared window the progress in the field accelerated. Many high-altitude observatories started their work in the last three decades of XXth century and since 1983 space observatories became most important due to the fact that infrared radiation penetrates through opaque cold shells. Moreover, cosmological expansion of the Universe shifts the maximum of spectral energy of distant hot objects from ultraviolet to near infrared region. Infrared astronomy is also essential for improving our knowledge of the cold universe, particularly for studies about the birth of stars, planetary systems and galaxies.

A Large Signal Model for CMUT Arrays with Arbitrary Membrane Geometries Operating in Non-Collapsed Mode

PubMed Central

Satir, Sarp; Zahorian, Jaime; Degertekin, F. Levent

2014-01-01

A large signal, transient model has been developed to predict the output characteristics of a CMUT array operated in the non-collapse mode. The model is based on separation of the nonlinear electrostatic voltage-to-force relation and the linear acoustic array response. For linear acoustic radiation and crosstalk effects, the boundary element method is used. The stiffness matrix in the vibroacoustics calculations is obtained using static finite element analysis of a single membrane which can have arbitrary geometry and boundary conditions. A lumped modeling approach is used to reduce the order of the system for modeling the transient nonlinear electrostatic actuation. To accurately capture the dynamics of the non-uniform electrostatic force distribution over the CMUT electrode during large deflections, the membrane electrode is divided into patches shaped to match higher order membrane modes, each introducing a variable to the system model. This reduced order nonlinear lumped model is solved in the time domain using Simulink. The model has two linear blocks to calculate the displacement profile of the electrode patches and the output pressure for a given force distribution over the array, respectively. The force to array displacement block uses the linear acoustic model, and the Rayleigh integral is evaluated to calculate the pressure at any field point. Using the model, the transient transmitted pressure can be simulated for different large signal drive signal configurations. The acoustic model is verified by comparison to harmonic FEA in vacuum and fluid for high and low aspect ratio membranes as well as mass-loaded membranes. The overall Simulink model is verified by comparison to transient 3D FEA and experimental results for different large drive signals; and an example for a phased array simulation is given. PMID:24158297

Comparative analysis of data quality and applications in vegetation of HJ-1A CCD images

NASA Astrophysics Data System (ADS)

Wei, Hongwei; Tian, Qingjiu; Huang, Yan; Wang, Yan

2014-05-01

To study the data quality and to find the differences in vegetation monitoring applications, the same region at Chuzhou Lai 'an, the data of HJ-1A CCD1 on the April 1st, 2012 and the data of HJ-1A CCD2 on the March 31, 2012 have being comparative analysis by the method of objective quality (image)assessment which selecting over five spectral image evaluation parameters: radiation precision (mean, variance, inclination, steepness), information entropy, signal-to-noise ratio, sharpness, contrast, and normalized differential vegetation index. The results show that there is little differences between the HJ-1A CCD1 and CCD2 by objective evaluation of data quality except radiation precision conform to their design theory, so the conclusion is that the difference of them without considering on the usual unless continuation;and Combination of field observation data Lai'an spectral data and GPS data (each point),selecting the normalized difference vegetation index as CCD1, CCD2 in vegetation monitoring application on the evaluation of the differences, and the specific process is based on GPS data is divided into nine small plots of spectral data ,and image data of nine one-to-one correspondence plots, and their normalized difference vegetation index values were calculated ,and measured spectra data resampling HJ-1A CCD1, CCD2 spectral response function calculated NDVI, and the results show that there is little differences between the HJ-1A CCD1 and CCD2 by objective evaluation of data quality, and, the differences of wheat `s reflection and normalized vegetation index is mainly due to calibration coefficients of CCD1 and CCD2, the differences of the solar elevation angle when obtaining the image and atmospheric conditions, so it has to consider the performance indicators as well as access conditions of CCD1 and CCD2, and to be take the normalization techniques for processing for the comparison analysis in the use of HJ-1A CCD Data to surface dynamic changes; Finally, in order to study the response of the spectral response function proposed spectral response function of impact factor, and in view of the spectral response function measured spectral data resampling only HJ-1A CCD spectral response function, calculated according to the formula of the equivalent reflectivity quantitative spectral response function, and spectral normalization of proposed theoretical Technical Support. The Objective evaluation of its application of HJ-1A CCD1, and CCD2 data quality differences research has important implications for broader application to further promote China-made remote sensing satellite data, future research also needs calibration coefficient, the solar elevation angle atmospheric conditions and its image scanning angle be taken into account, and to make the corresponding normalized its impact quantitative research has important significance for the timing changes in the application of the ecological environment in China.

Design and Calibration of a Novel Bio-Inspired Pixelated Polarized Light Compass.

PubMed

Han, Guoliang; Hu, Xiaoping; Lian, Junxiang; He, Xiaofeng; Zhang, Lilian; Wang, Yujie; Dong, Fengliang

2017-11-14

Animals, such as Savannah sparrows and North American monarch butterflies, are able to obtain compass information from skylight polarization patterns to help them navigate effectively and robustly. Inspired by excellent navigation ability of animals, this paper proposes a novel image-based polarized light compass, which has the advantages of having a small size and being light weight. Firstly, the polarized light compass, which is composed of a Charge Coupled Device (CCD) camera, a pixelated polarizer array and a wide-angle lens, is introduced. Secondly, the measurement method of a skylight polarization pattern and the orientation method based on a single scattering Rayleigh model are presented. Thirdly, the error model of the sensor, mainly including the response error of CCD pixels and the installation error of the pixelated polarizer, is established. A calibration method based on iterative least squares estimation is proposed. In the outdoor environment, the skylight polarization pattern can be measured in real time by our sensor. The orientation accuracy of the sensor increases with the decrease of the solar elevation angle, and the standard deviation of orientation error is 0 . 15 ∘ at sunset. Results of outdoor experiments show that the proposed polarization navigation sensor can be used for outdoor autonomous navigation.

Design and Calibration of a Novel Bio-Inspired Pixelated Polarized Light Compass

PubMed Central

Hu, Xiaoping; Lian, Junxiang; He, Xiaofeng; Zhang, Lilian; Wang, Yujie; Dong, Fengliang

2017-01-01

Animals, such as Savannah sparrows and North American monarch butterflies, are able to obtain compass information from skylight polarization patterns to help them navigate effectively and robustly. Inspired by excellent navigation ability of animals, this paper proposes a novel image-based polarized light compass, which has the advantages of having a small size and being light weight. Firstly, the polarized light compass, which is composed of a Charge Coupled Device (CCD) camera, a pixelated polarizer array and a wide-angle lens, is introduced. Secondly, the measurement method of a skylight polarization pattern and the orientation method based on a single scattering Rayleigh model are presented. Thirdly, the error model of the sensor, mainly including the response error of CCD pixels and the installation error of the pixelated polarizer, is established. A calibration method based on iterative least squares estimation is proposed. In the outdoor environment, the skylight polarization pattern can be measured in real time by our sensor. The orientation accuracy of the sensor increases with the decrease of the solar elevation angle, and the standard deviation of orientation error is 0.15∘ at sunset. Results of outdoor experiments show that the proposed polarization navigation sensor can be used for outdoor autonomous navigation. PMID:29135927

VizieR Online Data Catalog: Parallaxes for 1507 nearby mid-to-late M dwarfs (Dittmann+, 2014)

NASA Astrophysics Data System (ADS)

Dittmann, J. A.; Irwin, J. M.; Charbonneau, D.; Berta-Thompson, Z. K.

2016-08-01

The MEarth Observatory is an array consisting of eight identical f/9 40cm Ritchey-Chretien telescopes on German equatorial mounts at the Fred Lawrence Whipple Observatory on Mount Hopkins, Arizona. The telescopes are controlled robotically and collect data every clear night from September through July. The facility is closed every August for the summer monsoons. Each telescope contains a 2048*2048 pixel CCD with a pixel scale of ~0.76/pixel and a Schott RG715 glass filter with anti-reflection coating. The cutoff is defined by the CCD response, and the effective bandpass is similar to the union of the Sloan Digital Sky Survey i and z filters. The MEarth target list consists of ~1800 nearby M dwarfs selected from Lepine 2005 (cat. J/AJ/130/1680), a subset of the LSPM-North catalog (Lepine & Shara 2005, cat. I/298) believed to be within 33pc of the Sun. The subset of the MEarth sample presented here includes 1507 mid-to-late M dwarfs (see Table2) for which we can obtain reliable results. Of the 1507 stars, 1267 had no previous trigonometric parallax measurement. The data presented here covers the time period from 2008 September through 2013 July. (1 data file).

High-performance genetic analysis on microfabricated capillary array electrophoresis plastic chips fabricated by injection molding.

PubMed

Dang, Fuquan; Tabata, Osamu; Kurokawa, Masaya; Ewis, Ashraf A; Zhang, Lihua; Yamaoka, Yoshihisa; Shinohara, Shouji; Shinohara, Yasuo; Ishikawa, Mitsuru; Baba, Yoshinobu

2005-04-01

We have developed a novel technique for mass production of microfabricated capillary array electrophoresis (mu-CAE) plastic chips for high-speed, high-throughput genetic analysis. The mu-CAE chips, containing 10 individual separation channels of 50-microm width, 50-microm depth, and a 100-microm lane-to-lane spacing at the detection region and a sacrificial channel network, were fabricated on a poly(methyl methacrylate) substrate by injection molding and then bonded manually using a pressure-sensitive sealing tape within several seconds at room temperature. The conditions for injection molding and bonding were carefully characterized to yield mu-CAE chips with well-defined channel and injection structures. A CCD camera equipped with an image intensifier was used to monitor simultaneously the separation in a 10-channel array with laser-induced fluorescence detection. High-performance electrophoretic separations of phiX174 HaeIII DNA restriction fragments and PCR products related to the human beta-globin gene and SP-B gene (the surfactant protein B) have been demonstrated on mu-CAE plastic chips using a methylcellulose sieving matrix in individual channels. The current work demonstrated greatly simplified the fabrication process as well as a detection scheme for mu-CAE chips and will bring the low-cost mass production and application of mu-CAE plastic chips for genetic analysis.

A polarization measurement method for the quantification of retardation in optic nerve fiber layer

NASA Astrophysics Data System (ADS)

Fukuma, Yasufumi; Okazaki, Yoshio; Shioiri, Takashi; Iida, Yukio; Kikuta, Hisao; Ohnuma, Kazuhiko

2008-02-01

The thickness measurement of the optic nerve fiber layer is one of the most important evaluations for carrying out glaucoma diagnosis. Because the optic nerve fiber layer has birefringence, the thickness can be measured by illuminating eye optics with circular polarized light and analyzing the elliptical rate of the detected polarized light reflected from the optic nerve fiber layer. In this method, the scattering light from the background and the retardation caused by the cornea disturbs the precise measurement. If the Stokes vector expressing the whole state of polarization can be detected, we can eliminate numerically the influence of the background scattering and of the retardation caused by the cornea. Because the retardation process of the eye optics can be represented by a numerical equation using the retardation matrix of each component and also the nonpolarized background scattering light, it can be calculated by using the Stokes vector. We applied a polarization analysis system that can detect the Stokes vector onto the fundus camera. The polarization analysis system is constructed with a CCD area image sensor, a linear polarizing plate, a micro phase plate array, and a circularly polarized light illumination unit. With this simply constructed system, we can calculate the retardation caused only by the optic nerve fiber layer and it can predict the thickness of the optic nerve fiber layer. We report the method and the results graphically showing the retardation of the optic nerve fiber layer without the retardation of the cornea.

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

PubMed

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

2017-06-20

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

Recent developments in the MuCAT microtomography facility

NASA Astrophysics Data System (ADS)

Davis, Graham R.; Evershed, Anthony N. Z.; Mills, David

2012-10-01

The goal of the MuCAT scanner development at Queen Mary University of London is to provide highly accurate maps of a specimen's X-ray linear attenuation coefficient; speed of data acquisition and spatial resolution having a lower priority. The reason for this approach is that the primary application is to accurately map the mineral concentration in teeth. Synchrotron tomography would generally be considered more appropriate for such a task, but many of the dental applications involve repeated scans with long intervening periods (from hours to weeks) and the management of synchrotron facilities does not readily allow such research. Development work is concentrated in two areas: beam hardening correction algorithms and novel scanning methodology. Beam hardening correction is combined with calibration, such that the raw X-ray projection data is corrected for beam hardening prior to reconstruction. Recent developments include the design of a multi-element calibration carousel. This has nine calibration pieces, five aluminium, three titanium and one copper. Development of the modelling algorithm is also yielding improved accuracy. A time-delay integration CCD camera is used to avoid ring artefacts. The original prototype averaged out inhomogeneities in both the detector array and the X-ray field; later designs used only software correction for the latter. However, at lower X-ray energies, the effect of deposits on the X-ray window (for example) becomes more conspicuous and so a new scanning methodology has been designed whereby the specimen moves in an arc about the source and equiangular data is acquired, thus overcoming this problem.

Rapid Mueller matrix polarimetry imaging based on four photoelastic modulators with no moving parts (Conference Presentation)

NASA Astrophysics Data System (ADS)

Gribble, Adam; Alali, Sanaz; Vitkin, Alex

2016-03-01

Polarized light has many applications in biomedical imaging. The interaction of a biological sample with polarized light reveals information about its composition, both structural and functional. For example, the polarimetry-derived metric of linear retardance (birefringence) is dependent on tissue structural organization (anisotropy) and can be used to diagnose myocardial infarct; circular birefringence (optical rotation) can measure glucose concentrations. The most comprehensive type of polarimetry analysis is to measure the Mueller matrix, a polarization transfer function that completely describes how a sample interacts with polarized light. To derive this 4x4 matrix it is necessary to observe how a tissue interacts with different polarizations. A well-suited approach for tissue polarimetry is to use photoelastic modulators (PEMs), which dynamically modulate the polarization of light. Previously, we have demonstrated a rapid time-gated Stokes imaging system that is capable of characterizing the state of polarized light (the Stokes vector) over a large field, after interacting with any turbid media. This was accomplished by synchronizing CCD camera acquisition times relative to two PEMs using a field-programmable gate array (FPGA). Here, we extend this technology to four PEMs, yielding a polarimetry system that is capable of rapidly measuring the complete sample Mueller matrix over a large field of view, with no moving parts and no beam steering. We describe the calibration procedure and evaluate the accuracy of the measurements. Results are shown for tissue-mimicking phantoms, as well as initial biological samples.

Wide-Field CCD Photometry around Nine Open Clusters

NASA Astrophysics Data System (ADS)

Sharma, Saurabh; Pandey, A. K.; Ogura, K.; Mito, H.; Tarusawa, K.; Sagar, R.

2006-10-01

In this paper we study the evolution of the core and corona of nine open clusters using the projected radial density profiles derived from homogeneous CCD photometric data obtained with the 105 cm Kiso Schmidt telescope. The age and galactocentric distance of the target clusters vary from 16 to 2000 Myr and 9 to 10.8 kpc, respectively. Barring Be 62, which is a young open cluster, other clusters show a uniform reddening across the cluster region. The reddening in Be 62 varies from E(B-V)min=0.70 mag to E(B-V)max=1.00 mag. The coronae of six of the clusters in the present sample are found to be elongated; however, on the basis of the present sample it is not possible to establish any correlation between the age and shape of the core. The elongated core in the case of the young cluster Be 62 may reflect the initial conditions in the parental molecular cloud. The other results of the present study are as follows: (1) Core radius rc and corona size rcn/cluster radius rcl are linearly correlated. (2) The rc, rcn, and rcl are linearly correlated with the number of stars in that region. (3) In the age range 10-1000 Myr, the core and corona shrink with age. (4) We find that in the galactocentric distance range 9-10 kpc, the core and corona/cluster extent of the clusters increase with the galactocentric distance.

GBAS Ionospheric Anomaly Monitoring Based on a Two-Step Approach

PubMed Central

Zhao, Lin; Yang, Fuxin; Li, Liang; Ding, Jicheng; Zhao, Yuxin

2016-01-01

As one significant component of space environmental weather, the ionosphere has to be monitored using Global Positioning System (GPS) receivers for the Ground-Based Augmentation System (GBAS). This is because an ionospheric anomaly can pose a potential threat for GBAS to support safety-critical services. The traditional code-carrier divergence (CCD) methods, which have been widely used to detect the variants of the ionospheric gradient for GBAS, adopt a linear time-invariant low-pass filter to suppress the effect of high frequency noise on the detection of the ionospheric anomaly. However, there is a counterbalance between response time and estimation accuracy due to the fixed time constants. In order to release the limitation, a two-step approach (TSA) is proposed by integrating the cascaded linear time-invariant low-pass filters with the adaptive Kalman filter to detect the ionospheric gradient anomaly. The performance of the proposed method is tested by using simulated and real-world data, respectively. The simulation results show that the TSA can detect ionospheric gradient anomalies quickly, even when the noise is severer. Compared to the traditional CCD methods, the experiments from real-world GPS data indicate that the average estimation accuracy of the ionospheric gradient improves by more than 31.3%, and the average response time to the ionospheric gradient at a rate of 0.018 m/s improves by more than 59.3%, which demonstrates the ability of TSA to detect a small ionospheric gradient more rapidly. PMID:27240367

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.

Multi-segment detector array for hybrid reflection-mode ultrasound and optoacoustic tomography (Conference Presentation)

NASA Astrophysics Data System (ADS)

Merčep, Elena; Burton, Neal C.; Deán-Ben, Xosé Luís.; Razansky, Daniel

2017-02-01

The complementary contrast of the optoacoustic (OA) and pulse-echo ultrasound (US) modalities makes the combined usage of these imaging technologies highly advantageous. Due to the different physical contrast mechanisms development of a detector array optimally suited for both modalities is one of the challenges to efficient implementation of a single OA-US imaging device. We demonstrate imaging performance of the first hybrid detector array whose novel design, incorporating array segments of linear and concave geometry, optimally supports image acquisition in both reflection-mode ultrasonography and optoacoustic tomography modes. Hybrid detector array has a total number of 256 elements and three segments of different geometry and variable pitch size: a central 128-element linear segment with pitch of 0.25mm, ideally suited for pulse-echo US imaging, and two external 64-elements segments with concave geometry and 0.6mm pitch optimized for OA image acquisition. Interleaved OA and US image acquisition with up to 25 fps is facilitated through a custom-made multiplexer unit. Spatial resolution of the transducer was characterized in numerical simulations and validated in phantom experiments and comprises 230 and 300 μm in the respective OA and US imaging modes. Imaging performance of the multi-segment detector array was experimentally shown in a series of imaging sessions with healthy volunteers. Employing mixed array geometries allows at the same time achieving excellent OA contrast with a large field of view, and US contrast for complementary structural features with reduced side-lobes and improved resolution. The newly designed hybrid detector array that comprises segments of linear and concave geometries optimally fulfills requirements for efficient US and OA imaging and may expand the applicability of the developed hybrid OPUS imaging technology and accelerate its clinical translation.

Improvement of resolution in full-view linear-array photoacoustic computed tomography using a novel adaptive weighting method

NASA Astrophysics Data System (ADS)

Omidi, Parsa; Diop, Mamadou; Carson, Jeffrey; Nasiriavanaki, Mohammadreza

2017-03-01

Linear-array-based photoacoustic computed tomography is a popular methodology for deep and high resolution imaging. However, issues such as phase aberration, side-lobe effects, and propagation limitations deteriorate the resolution. The effect of phase aberration due to acoustic attenuation and constant assumption of the speed of sound (SoS) can be reduced by applying an adaptive weighting method such as the coherence factor (CF). Utilizing an adaptive beamforming algorithm such as the minimum variance (MV) can improve the resolution at the focal point by eliminating the side-lobes. Moreover, invisibility of directional objects emitting parallel to the detection plane, such as vessels and other absorbing structures stretched in the direction perpendicular to the detection plane can degrade resolution. In this study, we propose a full-view array level weighting algorithm in which different weighs are assigned to different positions of the linear array based on an orientation algorithm which uses the histogram of oriented gradient (HOG). Simulation results obtained from a synthetic phantom show the superior performance of the proposed method over the existing reconstruction methods.

A metagenomic survey of microbes in honey bee colony collapse disorder.

PubMed

Cox-Foster, Diana L; Conlan, Sean; Holmes, Edward C; Palacios, Gustavo; Evans, Jay D; Moran, Nancy A; Quan, Phenix-Lan; Briese, Thomas; Hornig, Mady; Geiser, David M; Martinson, Vince; vanEngelsdorp, Dennis; Kalkstein, Abby L; Drysdale, Andrew; Hui, Jeffrey; Zhai, Junhui; Cui, Liwang; Hutchison, Stephen K; Simons, Jan Fredrik; Egholm, Michael; Pettis, Jeffery S; Lipkin, W Ian

2007-10-12

In colony collapse disorder (CCD), honey bee colonies inexplicably lose their workers. CCD has resulted in a loss of 50 to 90% of colonies in beekeeping operations across the United States. The observation that irradiated combs from affected colonies can be repopulated with naive bees suggests that infection may contribute to CCD. We used an unbiased metagenomic approach to survey microflora in CCD hives, normal hives, and imported royal jelly. Candidate pathogens were screened for significance of association with CCD by the examination of samples collected from several sites over a period of 3 years. One organism, Israeli acute paralysis virus of bees, was strongly correlated with CCD.

The timing of events surrounding the Eocene-Oligocene boundary - Results from ODP Leg 199

NASA Astrophysics Data System (ADS)

Pälike, H.; Wilson, P. A.; Coxall, H.; Backman, J.

2003-04-01

The Eocene/Oligocene (E/O) boundary represents an extreme and rapid climatic transition from the ``greenhouse'' world of the Cretaceous and early Paleogene into the late Paleogene-Neogene ``ice-house''. It is marked by a large and global deepening in the calcite compensation depth (CCD), as well as pronounced changes in the isotopic composition of carbon and oxygen in seawater, recorded in biogenic calcium carbonate. A good understanding is still lacking as to why climatic, palaeoceanographic and marine biological productivity changes occurred within a few tens of thousands of years, and what change in boundary conditions triggered a non-linear response of the climate system. Detailed palaeoceanographic records surrounding the E/O have been rare because of the lack of well-dated, expanded deep-sea sedimentary sections containing well-preserved calcareous microfossils. Ocean Drilling Program Leg 199 recently recovered an extensive set of high-quality sediment cores across the E/O that span a latitudinal and depth transect in the central Pacific Ocean. We present new high-resolution records of bulk %CaCO3, δ18O and δ13C for a set of sites that form a depth transect, clearly delineating the relative depth with respect to the CCD during the transition. Our data show that a two-stepped deepening of the CCD coincides with a remarkably similar and simultaneous evolution of bulk δ18O values. We can demonstrate the imprint of climatic cycles around the E/O boundary, and very high-quality bio- and paleomagnetic datum points allow us to link these to Earth's orbital variations. Shipboard measurements of sediment properties and down-hole log measurements also display an imprint of climatic cycles, and allow us to obtain an astronomically calibrated time scale across the E/O. Our results put tighter constraints on the timing of the evolution of the CCD, mass accumulation rates, and biological productivity across the E/O, which display a distinct two-step shift in the most expanded section at the shallowest end of the transect (Site 1218). The initial deepening of the CCD occurred in less than 50 thousand years, and we observe a change in the nature and amplitude of climatic cycles that are recorded in sediments from Leg 199 across the E/O.

Power Pattern Sensitivity to Calibration Errors and Mutual Coupling in Linear Arrays through Circular Interval Arithmetics

PubMed Central

Anselmi, Nicola; Salucci, Marco; Rocca, Paolo; Massa, Andrea

2016-01-01

The sensitivity to both calibration errors and mutual coupling effects of the power pattern radiated by a linear array is addressed. Starting from the knowledge of the nominal excitations of the array elements and the maximum uncertainty on their amplitudes, the bounds of the pattern deviations from the ideal one are analytically derived by exploiting the Circular Interval Analysis (CIA). A set of representative numerical results is reported and discussed to assess the effectiveness and the reliability of the proposed approach also in comparison with state-of-the-art methods and full-wave simulations. PMID:27258274

Linear laser diode arrays for improvement in optical disk recording for space stations

NASA Technical Reports Server (NTRS)

Alphonse, G. A.; Carlin, D. B.; Connolly, J. C.

1990-01-01

The design and fabrication of individually addressable laser diode arrays for high performance magneto-optic recording systems are presented. Ten diode arrays with 30 mW cW light output, linear light vs. current characteristics and single longitudinal mode spectrum were fabricated using channel substrate planar (CSP) structures. Preliminary results on the inverse CSP structure, whose fabrication is less critically dependent on device parameters than the CSP, are also presented. The impact of systems parameters and requirements, in particular, the effect of feedback on laser design is assessed, and techniques to reduce feedback or minimize its effect on systems performance, including mode-stabilized structures, are evaluated.

Acoustic contrast control in an arc-shaped area using a linear loudspeaker array.

PubMed

Zhao, Sipei; Qiu, Xiaojun; Burnett, Ian

2015-02-01

This paper proposes a method of creating acoustic contrast control in an arc-shaped area using a linear loudspeaker array. The boundary of the arc-shaped area is treated as the envelope of the tangent lines that can be formed by manipulating the phase profile of the loudspeakers in the array. When compared with the existing acoustic contrast control method, the proposed method is able to generate sound field inside an arc-shaped area and achieve a trade-off between acoustic uniformity and acoustic contrast. The acoustic contrast created by the proposed method increases while the acoustic uniformity decreases with frequency.

Advanced Wavefront Sensor Concepts.

DTIC Science & Technology

1981-01-01

internal optics (a) Characteristics (see Figure 47) - Intensification with a 256 element linear self scanned diode array - Optical input; lenticular ...34 diameter - Lenticular array input to fiber optics which spread out to tubes - Photon counting for low noise fac- tor (b) Pe r fo rmance - Bialkali...problem in making the lenslet arrays in the pupil divider rectangular. The last optical elements are the lenticular lens arrays. In this group, the first

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).