Showing papers on "Night vision published in 1998"

Effect of pupillary dilation on corneal optical aberrations after Photorefractive keratectomy

Abstract: Background: Complaints of glare, halos, and disturbances of night vision after photorefractive keratectomy (PRK) probably result from changes in the corneal aberration structure induced by the laser ablation procedure. The purpose of this article is to characterize changes in the corneal aberration structure after PRK and to demonstrate the effect of pupil dilation on these changes. Methods: Videokeratographs obtained preoperatively (n = 112) and at 1 (n = 94), 3 (n = 103), 6 (n = 91), 12 (n = 60), 18 (n = 53), and 24 (n = 44) months postoperatively from 112 eyes of 89 patients who had undergone PRK for myopia were analyzed. The data were used to calculate the wavefront variance of the cornea for both small (3-mm) and large (7-mm) pupils. Results: For both the 3- and 7-mm pupil, coma-like aberrations increased significantly from preoperative values to 1-month postoperative values (P,.05 and P,.001, respectively); for 7-mm pupils, the postoperative values never returned to preoperative values (P,.001, 24 months). For the 3-mm pupil, spherical-like aberrations decreased significantly 1 month after surgery (P,.001), and never returned to preoperative values. For the 7-mm pupil, spherical-like aberrations increased significantly 1 month after surgery (P,.001) and did not return to preoperative values. Opening the pupil from 3 to 7 mm increased spherical-like aberrations only 7-fold before PRK. After PRK, however, pupillary dilation caused a 300-fold increase in this type of aberration. For both pupil sizes at all times after PRK, the magnitude of the surgically induced aberration correlated with the amount of the attempted correction (P,.001, r 2 = 0.6 at 1 month for a 7-mm pupil). Conclusions: Photorefractive keratectomy increases the wavefront variance of the cornea; PRK changes the relative contribution of coma-like and spherical-like aberrations; after PRK, the diameter of the entrance pupil greatly affects the amount and character of the aberrations; and the magnitude of the aberration increases with the attempted correction. Clinical Relevance: Quantitative characterization of irregular astigmatism with the measurement of aberration structures following corneal surgery and the correlation of these data with visual performance in clinical trials provide the basis for understanding patient complaints and for improving surgical approaches. Our analysis shows that, whereas induced aberrations are minimal for simulated daytime vision (3-mm pupil), the increase in aberrations measured for simulated night vision (7-mm pupil) supports the use of large treatment zones to reduce visual disturbances such as glare and halos.

Thermographic detection of breast cancer

Abstract: The author outlines the historical attempts made to use infrared thermography for breast cancer detection. He concludes that the technique was a great idea that failed. One can produce good thermal images of the breast, and these images often show features that reflect disease. But the association between skin temperature and breast cancer is too weak to be useful, given the need to detect small tumors and the statistics of breast cancer. However, infrared imaging has experienced great progress in recent years, which is a result of military research in night vision. Several groups in the U.S., Canada, and Japan are experimenting with advanced thermographic systems for detection of breast cancer. This work, the "new thermography", is still in preliminary stages and no extensive clinical studies have apparently been published. The obvious hope is that improved thermal sensitivity will result in improved sensitivity as a medical test -a plausible but so far unproven hypothesis. Detection of breast cancer graphically illustrates the very large difference between getting a medical technology to "work" in a technical or engineering sense, and in meeting the needs of physicians and their patients. There is also a difference between observing promising results with individual patients, and in showing that a technique will benefit the many patients with whom it will be used. We would do our students a favor by helping them to understand the difference. And those who fail to learn the lessons of the past may have to repeat them again.

Real-time fusion of low-light CCD and uncooled IR imagery for color night vision

Abstract: We present an approach to color night vision through fusion of information derived from visible and thermal infrared sensors. Building on the work reported at SPIE in 1996 and 1997, we show how opponent-color processing and center-surround shunting neural networks can achieve informative multi-band image fusion. In particular, by emulating spatial and color processing in the retina, we demonstrate an effective strategy for multi-sensor color-night vision. We have developed a real- time visible/IR fusion processor from multiple C80 DSP chips using commercially available Matrox Genesis boards, which we use in conjunction with the Lincoln Lab low-light CCD and a Raytheon TI Systems uncooled IR camera. Limited human factors testing of visible/IR fusion is presented showing improvements in human performance using our color fused imagery relative to alternative fusion strategies or either single image modality alone. We conclude that fusion architectures that match opponent-sensor contrast to human opponent-color processing will yield fused image products of high image quality and utility.

Softgel capsule containing Dha and antioxidants

Abstract: This invention provides a nutritional supplement containing docosahexaenoic acid (DHA), antioxidants and anthocyanosides. The supplement is useful for improving night vision acuity, field of vision and adaptation to light.

Effects of Fenretinide (4-HPR) on Dark Adaptation

Abstract: Objectives To assess the alterations in dark adaptation induced by low (200 mg/d) doses of fenretinide (4-HPR), to assess whether these effects were cumulative and whether they were reversible, and to attempt to elucidate the mechanism underlying the changes in night vision. Design Case series. Setting Outpatient eye clinic. Patients Twenty-two women enrolled in a breast cancer chemoprevention trial, and 18 normal control subjects. Intervention Measurements of absolute luminance thresholds during dark adaptation. Main Outcome Measures Parameters of an exponential model of the dark-adaptation function before, during, and after administration of fenretinide. Results The most conspicuous effect of fenretinide on dark adaptation was a significant delay in the timing of the rod-cone break ( P Conclusion The dose of fenretinide used in this study produced clearly measurable, but not severe, changes in night vision, which were rarely symptomatic.

Integrated car dubbing system

Abstract: The present invention is a vehicular wireless audio/video record/playback unit, wherein the unit detects satellite, AM/FM radio and television broadcasts including new music release and live music and entertainment events and upon detection of a commercial break, station break, distortion or satellite interruptions, the unit pauses a recording function until the commercial or station break, distortion or satellite interruptions are eliminated. The unit supports internet access, on-line banking, stock market trading, commodity and precious stone/metal trading. When integrated into the vehicular audio system and led screen the microphone and infra red night vision camera provide for telephone/video conferencing, recording of impacts and unwarranted intruder with audible sound that alerts the motorist when the camera senses fatigue, and a retractable assembly mechanism that uses the vehicular ignition switch to retrieve, retract and/or bypass the unit in the vehicular electronic compartment, wherein the unit have a record/playback memory space, high speed dubbing/memory erase and sensor configuration with the remote control peripheral for accessing the unit at any convenient seat position and a dual purpose audio/video track disk having software downloaded as the unit for rebooting the cd player or re-configure the unit if there was a unit failure.

Night vision monocular device

Abstract: A monocular night vision device comprising an objective lens assembly for receiving low intensity light; an image intensifier assembly comprising a variable gain image intensifier tube having an adjustable potentiometer mounted external to the tube for converting the low intensity light into a visible output image; a single eyepiece lens assembly for viewing the output image from the image intensifier assembly; and a non-metallic housing for receiving the objective lens assembly, image intensifier assembly, and eyepiece lens assembly, wherein the housing aligns the objective lens assembly with the image intensifier assembly and the eyepiece lens assembly along an optical axis.

Automatic long-life infrared emitter & locator system

Abstract: An Automatic Long-Life Infrared Emitter & Locator System which may be used to locate persons in need of assistance or marked objects is disclosed. Since the emitter (10) operates continuously and emanates infrared radiation (21) that can not be seen by the user, no affirmative action is required to activate the emitter (10). One of the preferred embodiments of the present invention (10) includes a flexible plastic or rubber housing (12) having an opening (15) that is specially shaped to fit over and to finly grasp a conventional electrical battery (16). A lens (18) residing on the top of the housing (12) passes invisible energy issuing from an infrared emitting diode (20) deployed beneath it. The diode (20) is connected to the battery (16) by leads (19) through a pulse control circuit (22). This circuit (22) produces intense and regular spikes of energy that cause the diode (20) to flash over a period of many weeks. The preferred embodiment (10) may be worn on a hiker's shirtsleeve (42) or hat (40), or may be installed on equipment carried by the hiker, such as a backpack (44). The invention may be attached to a boat (50), a car (52) or a skipole (46). This innovative device can be used to mark virtually any location, or could be employed to identify friendly troops on the battlefield. When combined with commercially available night vision equipment, the emitter (10) can help pinpoint any location that may not otherwise be perceived by the unaided eye.

Opponent-Color Fusion of Multi-Sensor Imagery: Visible, IR and SAR

Abstract: : The primary motivation for multi-sensor image fusion is to combine the complementary information derived from different modality sensors. Building on the work reported in two of our earlier papers from IRIS Passive Sensors 1996, we show how opponent-color processing and center-surround shunting neural networks can be used to develop a variety of image fusion architectures. By emulating single-opponent color processing cells in the retina, and double-opponent color cells in primary visual cortex, we demonstrate an effective strategy for color image fusion as applied to: low-light visible and thermal IR fusion for color night vision, 6-band multispectral fusion for camouflage detection, EO/IR/SAR multi-modal fusion from separate sensor platforms. We have also developed a realtime visible/IR fusion processor from multiple C80 DSP chips using commercially available boards, and use it in conjunction with the Lincoln Lab low-light CCD and an uncooled IR camera. Limited human factors testing of visible/IR fusion has shown improved human performance using our color fused imagery as compared to alternative fusion strategies or either single image modality alone. We conclude that fusion architectures which match opponent-sensor contrasts to human opponent-color pathways will yield fused image products of high image quality and utility.

If a Lion Could Talk: Animal Intelligence and the Evolution of Consciousness

Abstract: How many of us have caught ourselves gazing into the eyes of a pet, wondering what thoughts lie behind those eyes? Or fallen into an argument over which is smarter, the dog or the cat? Scientists have conducted elaborate experiments trying to ascertain whether animals from chimps to pigeons can communicate, count, reason, or even lie. So does science tell us what we assume-- that animals are pretty much like us, only not as smart? Simply, no. Now, in this superb book, Stephen Budiansky poses the fundamental question: "What is intelligence?" His answer takes us on the ultimate wildlife adventure to animal consciousness. Budiansky begins by exposing our tendency to see ourselves in animals. Our anthropomorphism allows us to perceive intelligence only in behavior that mimics our own. This prejudice, he argues, betrays a lack of imagination. Each species is so specialized that most of their abilities are simply not comparable. At the mercy of our anthropomorphic tendencies, we continue to puzzle over pointless issues like whether a wing or an arm is better, or whether night vision is better than day vision, rather than discovering the real world of a winged nighthawk, a thoroughbred horse, or an African lion. Budiansky investigates the sometimes bizarre research behind animal intelligence experiments: from horses who can count or ace history quizzes, and primates who seem fluent in sign language, to rats who seem to have become self-aware, he reveals that often these animals are responding to our tiny unconscious cues. And, while critically discussing scientists' interpretations of animal intelligence, he is able to lay out their discoveries in terms of what we know about ourselves. For instance, by putting you in the minds of dogs or bees who travel by dead reckoning, he demonstrates that this is also how you find your way down a familiar street with almost no conscious awareness of your navigation system. Modern cognitive science and the new science of evolutionary ecology are beginning to show that thinking in animals is tremendously complex and wonderful in its variety. A pigeon's ability to find its way home from almost anywhere has little to do with comparative intelligence; rather it is due to the pigeon's very different perception of the world. That's why, as Wittgenstein said, "If a lion could talk, we would not understand him." In this fascinating book, Budiansky frees us from the shackles of our ideas about the natural world, and opens a window to the astounding worlds of the animals that surround us.

The effect of anthocyanosides on night vision.

Abstract: Purpose In view of research demonstrating the ability of anthocyanosides in a single oral dose to improve night vision in normal individuals, it was decided to evaluate their effect on three night vision tests: full-field scotopic retinal threshold (SRT), dark adaptation rate (DAR) and mesopic contrast sensitivity (MCS). Methods In a double-masked, placebo-controlled, cross-over study, 16 young normal volunteers were randomly assigned to one of four different regimens of single oral administrations of 12, 24 and 36 mg of anthocyanosides, and a placebo, with a 2 week washout period between doses. SRT, DAR and MCS were measured immediately before, and 4, 8 and 24 h after treatment. Results No significant effect was found on any of the three night vision tests during the 24 h following a single oral administration of 12, 24 or 36 mg anthocyanosides. The study had a power of 0.95 to detect a 0.1 log unit improvement in SRT and 0.5 log unit improvement in MCS. Conclusions Single oral administration of 12-36 mg of anthocyanosides appears to lack significant effect on militarily relevant night vision tests.

Detection probability using relative clutter in infrared images

Abstract: Clutter plays a very important role in the area of machine and human-in-the-loop target acquisition. A great deal of interest has recently been shown in assessing several different definitions of clutter. In spite of so many definitions available, no single clutter definition has been agreed on by the target acquisition modeling community as being the best. Here we develop a new clutter metric, called relative clutter, based on factor analysis which is extensively used for statistical analysis. This relative clutter combines many definitions of clutter. Different methods for calculating the relative clutter based on the magnitude of the eigenvalues obtained from the correlation matrix are suggested. The relative clutter of many images is analyzed. The relative clutter is used to calculate probability of detection on Night Vision Lab (NVL) Terrain Board Infrared images.

Night Vision Goggle Research and Training Issues for Ground Forces: A Literature Review

Abstract: : A review of the night vision goggle (NVG) literature published over a 30-year period was conducted to identify NVG training issues that should be addressed to enhance the performance of ground forces. First-, second-, and third-generation image intensification devices are covered. Although the focus is on ground forces, research that addressed aviation issues is also included. The review documents bow soldier performance has improved from advancements in image intensification technology as well as from concerted efforts to address some long-standing training problems. Training research and development issues identified are: determining techniques to train soldiers on NVG technology and its application to night tasks, how to train soldiers to integrate NVGs with other equipment, training to enhance distance estimation abilities of soldiers when using NVGs, and training to improve mounted and dismounted navigation skills with NVGs. Attention must also be paid to developing training techniques that will enable soldiers to overcome the learning plateaus and human factors problems with NVGs so they become truly skilled at night with NVGs.

Telescopic sight with detachable night vision apparatus

Abstract: An object of the present invention is to provide a telescopic sight which is characterized by the fact that in a telescopic sight for day and night use, [a] a night time imaging device can be connected without removing the ocular tube body connected to the ocular side of the objective tube body when there is a changeover from day time use to night time use, so that the telescopic sight can be used at night, [b] the sight can be used "as is" as a day time sight by removing the night time imaging device, and [c] attachment or detachment for day time or night time use can be accomplished quickly, easily and reliably by means of one hand while the gun is held in the other hand.

Applying Critical Chain to improve the management of uncertainty in projects

Abstract: In an ever-intensifying global competitive market, the management of projects, particularly product development efforts, increasingly is one of the few areas that can produce a sustained competitive advantage Firms that can bring products to market faster can extract higher initial margins, can be more responsive to their customers, and will have products with longer sales lives Critical Chain is a new methodology that applies Eli Goldratt’s Theory of Constraints to project management in order complete projects faster and with greater predictability while simultaneously making more efficient use of resources The Critical Chain method accomplishes this by building project networks with average task durations, aggregating buffer at the end of projects where it can absorb unplanned iterations and other delays, and de-conflicting resources, both within and across projects This new project management methodology was researched by spending seven months on site with ITT Night Vision and applying the method to two product development projects In addition, benchmarking studies of previous product development efforts at the same site and of another lead user of the tool were conducted to provide both qualitative and quantitative comparison data Critical Chain appears to minimize schedule risk while simultaneously minimizing project duration, and has the potential to improve both communication and employee morale Thesis supervisors: Steven D Eppinger, Associate Professor, Sloan School of Management Anna Thornton, Assistant Professor, Department of Mechanical Engineering

Night vision device and method

Abstract: A night vision device (NVD) includes a control circuit (34) having an acceleration-responsive switch (48). When the NVD is in a generally horizontal use position, the acceleration-responsive switch (48) enables a circuit allowing voltage to be applied to an image intensifier tube (26) of the night vision device, so that night vision is provided. On the other hand, when the device is flipped up to a stowed position allowing the user of the device unobstructed natural vision, the acceleration-responsive switch (48) senses the changed orientation of the gravitational acceleration vector, and turns off the image intensifier tube (26) as well as other light-emitting sources of the night vision device.

Evaluation of the impact of multispectral image fusion on human performance in global scene processing

Abstract: : An observer extracts local and global information from a natural scene to form a visual perception. Neisser and Treisman demonstrated that a natural scene contains different types of features, i.e., color, edges, luminance, and orientation to aid visual search. Infrared and visible sensors present nighttime images to an observer to aid target detection. These sensors present the observer an adequate representation of a nighttime scene, but sometimes fail to provide quality features for accurate visual perception. The purpose of this thesis is to investigate whether color features (combining an infrared and visible sensor image) improve visual scene comprehension compared to single band grayscale features during a signal detection task. Twenty three scenes were briefly presented in four different sensor formats (infrared, visible, fused monochrome, and fused color) to measure subjects global visual ability to detect whether a natural scene was right side up or upside down. Subjects are significantly more accurate at detecting scene orientation for an infrared and fused color scene compared to a fused monochrome and visible scene. Both the infrared and fused color sensor formats provide enough essential features to allow an observer to perceptually organize a complex nighttime scene.

Flight testing of a binocular bisensor HMD for helicopter: some human factors aspects

Abstract: The need for night vision system in military helicopter has been recognized for many years now. Besides fixed FLIR and night vision goggles, helmet-mounted systems coupled with head-slaved IR sensor have been introduced during the last decade in modern attack helicopters. Monocular HMDs have been fielded on the AH-64 and used in operation. Human factors aspects pertaining to such night vision devices has been extensively reviewed and published. Though, full scale flight tests of binocular HMDs with integrated I2 and head coupled IR sensors have rarely been reported. A binocular helmet, with a 40 degree full overlap FOV has been developed under a contract of the French DGA. Two image intensifiers tubes located on each side of the head are integrated on the helmet, which also has full raster and stroke capacity. Both images are projected on the visor of the helmet and collimated to infinity. IR sensor imagery and navigation system are coupled to the helmet using an electro-magnetic head-tracker. Test flight of the helmet have been conducted by the French Flight Test Center on specially equipped Puma test-bed aircraft. Approximately 150 flight hours have been devoted to testing of the helmet, either with I2 and IR sensors.

Infrared imager employing a 160 x 120 pixel uncooled bolometer array

Abstract: 9600 54th Avenue North, Suite 105Minneapolis, MN 55442Andrew Wood and Tom RezachekHoneywell Technology CenterI 2001 State Highway 55Plymouth, MN 55441-4799ABSTRACTWe have developed an uncooled thermal imager having 160x120, 50 pm x 50 pm pixels which operates at30 Hz frame rate. It employs a complementary metal oxide silicon (CMOS) readout integrated circuit(ROIC) beneath a vanadium oxide (VOx) silicon microstructure bolometric array. Imagery output is in RS-170 format. An RS-232 port can be employed to command operation from a remote location. Weight ofthe "engine," consisting of the focal plane array in its package plus three circuit boards, each 3x3 inches,is 8 oz. Input power is 2.5 Watts. Also included on the boards is a circuit which avoids the need for atemperature stabilizer in the array package. Operating in the 8—14 pm spectral interval, the imager has anoise equivalent temperature difference (NETD) with an f/0.8 lens against 295K targets of 0.IC. Thedynamic range of 66 dB will accommodate very hot targets without saturation of an image which alsocontains 290K targets.I . INTRODUCTIONInfrared Solutions, Inc. (151), with Honeywell Technology Center (HTC) as subcontractor, has completedthe development of an uncooled thermal imager, funded by the U.S. Army Communications—ElectronicsCommand (CECOM) Night Vision and Electronic Sensors Directorate (NVESD) under a Small BusinessInnovation Research (SBIR) Phases I and II contract. The imager, having 160x120 pixels, each 50 pm x50 pm, operates at U.S. TV frame rate. It employs a CMOS ROIC with VOx silicon microstructurebolometric pixels. It can be thought of as a half-scale version of the HTC uncooled bolometer imager"with a CMOS ROIC replacing the original bipolar one.The objective of the development was to reduce the size, weight, power and cost of bolometric thermalimagers so as to make them more affordable and to open up new applications, compared with the320x240 pixel uncooled bolometric thermal imagers developed by the Honeywell licensees.25 In sodoing, we believe that our bolometric imager will be able to compete effectively in price with electricallybiased pyroelectric uncooled hybrid array imagers which sell for less than the 320x240 bolometer arrayimagers, but have a very limited dynamic range and require a radiation chopper. New applications includesurveillance and security where low power, small size and remote command input are important andothers where light weight and small size are important, such as for body-mounted or head-mounted,hands-free operation for soldiers and firefighters.Our effort was divided into two major developments: the 160x120 pixel bolometric focal plane array andits vacuum package, and the off-chip electrical circuitry plus the embedded software. Development of thefocal plane array was the responsibility of HTC; they subcontracted design and development of the ROICto the Honeywell Solid State Electronics Center (SSEC). Design of the off-chip electronics, consisting ofanalog and digital circuits, power supply, RS-170 and RS-232 ports, and control of the thermoelectric

A comparison of stereopsis with ANVIS and F4949 night vision goggles

Abstract: BACKGROUND: This study was undertaken to see if the model of NVG affects stereoacuity. METHODS: We tested 13 male and 2 female aircrew with the Aviator's Night Vision Imaging System (ANVIS) and F4949 NVGs. Visual acuity was measured using the NVG Resolution Grid and stereopsis was determined using a modified Howard-Dolman test. RESULTS: In simulated light conditions, average stereoscopic threshold using the F4949 NVG (17.35 arc s) was not significantly better than the ANVIS NVG (18.42 arc s), the mean difference being 1.07 arc s (95% confidence limits, -2.85 to 4.99). CONCLUSIONS: The Howard-Dolman test proved to be effective in eliminating monocular clues, thus validating its use in testing NVG stereopsis. The distribution of visual acuities across subjects and goggle models was too narrow to evaluate the effect of visual acuity on stereoacuity in NVGs. Differences in trial means during the course of the study indicated the presence of a "learning" effect on the Howard-Dolman test. Language: en

Design of three-element night-vision goggle objectives

Abstract: Night-vision goggle objectives are often composed of six or more conventional lens elements with spherical surfaces and homogeneous refractive indices. Special elements such as aspheres, diffractive optics, and gradient-index materials can be used to reduce the total number of lenses required to meet military design specifications. A study was performed to examine the use of various combinations of these special surfaces to determine the minimum number of elements that can be used to construct the objective system. We present and compare the best resulting designs.

Report on the Advanced Technology Demonstration (ATD) of the Vehicular- Mounted Mine Detection (VMMD) Systems at Aberdeen, Maryland, and Socorro, New Mexico.

Abstract: : This document presents an analysis of the results of an advanced technology demonstration of five vehicular-mounted mine detection systems developed for the detection of antitank land mines. The five contractors were Coleman Research Corporation; Computing Devices Canada; EGG GDE Systems, Inc.; and GeoCenters, Inc. The systems were developed for the U.S. Army Night Vision and Electronic Sensors Directorate. The advanced technology demonstration took place at the Aberdeen Test Center, Aberdeen, Maryland, on June 8-19, 1998, and the Energetic Materials Research and Testing Center, Socorro, New Mexico, on July 13-24, 1998. The purpose of the program is to develop the technology for a remotely operated vehicle that will detect mines and mark their locations during military mine-clearance operations. The system will ultimately consist of a mine overpass vehicle upon which is mounted a sensor system that detects mines and a communication system that provides data transfer between the detection vehicle and the remote operator. The mine threats include both metal-cased mines and mines with low-metal content. These mines may be laid on ground surface or buried underground. The report outlines the systems' performance, in particular their detection probability and false-alarm rates, compared to the program's requirements.

Night vision monocular

Abstract: A night vision monocular having an optical axis is provided which includes a housing having a distal end and a proximal end; an objective lens assembly having at least one objective lens, the objective lens assembly being engaged within the housing at the distal end; an eyepiece lens assembly having at least one eyepiece lens, the eyepiece lens assembly being engaged within the housing at the proximal end; and an image intensifying tube being engaged within the housing between the objective lens assembly and the eyepiece lens assembly and optically communicating with the objective lens assembly and the eyepiece lens assembly, such that light entering the night vision monocular via the objective lens assembly is intensified via the image intensifying tube and further such that the intensified light is focused via the eyepiece lens assembly onto an eye of a viewer. At least one of the objective lens assembly and the eyepiece lens assembly includes at least one eccentrically rotatable eccentric element, whereas the objective lens assembly and the eyepiece lens assembly include, in combination, a minimum of two eccentrically rotatable eccentric elements, so as to enable to self collimate the optical axis of the night vision monocular within a predetermined image offset range, so as to enable to combine two night vision monoculars at random into an adjustment-free night vision binocular.

Multizone and Transition Zone Photorefractive Keratectomy for High Myopia

Abstract: BACKGROUND Variations in ablation profile may alter the stability of refraction and cause adverse effects in photorefractive keratectomy. We compared the benefits of multizone and transition zone ablation in the treatment of high and extreme myopia. METHODS A scanning excimer laser system, Nidek EC-5000 was used with three-zone treatment and our results were compared retrospectively with results obtained in a group with a conventional ablation profile using a transition zone. RESULTS Six-month follow-up data were available for 65 eyes with a transition zone and 46 eyes with three-zone treatment. Postoperative mean (+/- SD) healing time was 2.98 days (+/- 0.12) and 3.02 days (+/- 0.15) and night vision disturbances were 16% and 11.5% respectively, (p > 0.05). Refractive regression was also similar in the two groups; uncorrected visual acuity of 20/40 or better was 90.77% and 89.14%. At 6 months postoperatively, the mean (+/- SD) corneal clarity score was 0.61 (+/- 0.29) in the transition zone group, and 0.51 (+/- 0.07) in the multizone group (p < 0.05). CONCLUSION No discernible differences between treatments were found in either epithelial healing or refractive outcome, such as regression, between the groups. Corneal haze was less in eyes treated with three-zone ablation.

640/spl times/480 back-illuminated CCD imager with improved blooming control for night vision

Abstract: We describe a back-illuminated 640/spl times/480 CCD imager which operates at 30-Hz frame rates with 5 e/sup -/ noise and which is capable of high resolution down to near starlight illumination levels A new process for fabricating a compact blooming control is also described

Multispectral simulation environment for modeling low-light-level sensor systems

Abstract: Image intensifying cameras have been found to be extremely useful in low-light-level (LLL) scenarios including military night vision and civilian rescue operations. These sensors utilize the available visible region photons and an amplification process to produce high contrast imagery. It has been demonstrated that processing techniques can further enhance the quality of this imagery. For example, fusion with matching thermal IR imagery can improve image content when very little visible region contrast is available. To aid in the improvement of current algorithms and the development of new ones, a high fidelity simulation environment capable of producing radiometrically correct multi-band imagery for low- light-level conditions is desired. This paper describes a modeling environment attempting to meet these criteria by addressing the task as two individual components: (1) prediction of a low-light-level radiance field from an arbitrary scene, and (2) simulation of the output from a low- light-level sensor for a given radiance field. The radiance prediction engine utilized in this environment is the Digital Imaging and Remote Sensing Image Generation (DIRSIG) model which is a first principles based multi-spectral synthetic image generation model capable of producing an arbitrary number of bands in the 0.28 to 20 micrometer region. The DIRSIG model is utilized to produce high spatial and spectral resolution radiance field images. These images are then processed by a user configurable multi-stage low-light-level sensor model that applies the appropriate noise and modulation transfer function (MTF) at each stage in the image processing chain. This includes the ability to reproduce common intensifying sensor artifacts such as saturation and 'blooming.' Additionally, co-registered imagery in other spectral bands may be simultaneously generated for testing fusion and exploitation algorithms. This paper discusses specific aspects of the DIRSIG radiance prediction for low- light-level conditions including the incorporation of natural and man-made sources which emphasizes the importance of accurate BRDF. A description of the implementation of each stage in the image processing and capture chain for the LLL model is also presented. Finally, simulated images are presented and qualitatively compared to lab acquired imagery from a commercial system.

A CMOS current mirroring integration readout structure for infrared focal plane arrays

Abstract: This paper reports a new, high performance CMOS readout structure, called Current Mirroring Integration (CMI), for high-resolution infrared Focal Plane Array (FPA) applications. Using the integration capacitance outside the FPA, the unit cell area is decreased, making the circuit suitable for high-resolution applications. Moreover, the readout circuit offers high injection efficiency, perfect (almost-zero) detector bias, and large dynamic range in a small pixel area. The circuit provides a maximum charge storage capacity of 5.25×107electrons and a maximum transimpedance of 6×107Ω for a 2pF integration capacitance and 5V power supply. The unit-cell employs only nine MOS transistors and occupies an area of 20µm × 25µm in a 0.8µm CMOS process.

Evaluation of the human factors implications of jaguar's first prototype near infrared night vision system

Abstract: This paper reports on the results of human factors evaluations carried out on a prototype near infra red night vision system. This system was taken from a military aircraft application and installed in a 4-litre Jaguar Sovereign by Jaguar Cars Ltd; this was done for the express purpose of understanding more about the issues concerned with the use of night time imaging technology in a driving situation. Although the system is appropriate to its aeronautical military application, it was understood from the outset to be unsuitable (in its current form) in an automotive environment. The main objective of installing the unit in the car was to provide an opportunity to gain experience quickly of the technologies involved and to develop an understanding of customer requirements and acceptance issues. The evaluations also made it possible to begin to address the issues of packaging, installation, cost and reliability. For the covering abstract see IRRD E102207.