Showing papers on "Night vision published in 1990"

Mutations within the Rhodopsin Gene in Patients with Autosomal Dominant Retinitis Pigmentosa

Abstract: Background. Night blindness is an early symptom of retinitis pigmentosa. The rod photoreceptors are responsible for night vision and use rhodopsin as the photosensitive pigment. Methods and Results. We found three mutations in the human rhodopsin gene; each occurred exclusively in the affected members of some families with autosomal dominant retinitis pigmentosa. Two mutations were C-to-T transitions involving separate nucleotides of codon 347; the third was a C-to-G transversion in codon 58. Each mutation corresponded to a change in one amino acid residue in the rhodopsin molecule. None of these mutations were found in 106 unrelated normal subjects who served as controls. When the incidence of these three mutations was added to that of a previously reported mutation involving codon 23, 27 of 150 unrelated patients with autosomal dominant retinitis pigmentosa (18 percent) were found to carry one of these four defects in the rhodopsin gene. All 27 patients had abnormal rod function on monitoring o...

Direct incorporation of night vision in a helmet mounted display

Abstract: Helmet mounted display apparatus for use in aircraft and rotorcraft includes an first image source for generating images comprising pilotage symbol information, a second image source for sensing and generating images of the exterior scene, and relay optical components that optically superimpose the two images together and subsequently project the superimposed image into the observer's forward field of view.

Night Vision: Basic, Clinical and Applied Aspects

Abstract: Part I. Normal Vision Sensitivity: 1. Rod vision R. F. Hess 2. Light adaptation of the rods L. T. Sharpe 3. Physiological mechanisms of visual adaptation M. K. Powers, D. G. Green and J. G. Robson 4. Absolute sensitivity W. Makous 5. Dark adaptation: a re-examination T. D. Lamb 6. Invertebrate vision at low luminances S. B. Laughlin Part II. Achromatopsia: 7. Total colour blindness: an introduction L. T. Sharpe and K. Nordby 8. Vision in a complete achromat: a personal account K. Nordby 9. Clinical aspects of achromatopsia E. Hansen 10. The photreceptors in the achromat L. T. Sharpe and K. Nordby 11. Post receptoral sensitivity of the achromat R. F. Hess Part III. Clinical and Applied: 12. The loss of night vision: clinical manifestations in man and animals H. Ripps and G. A. Fishman 13. Aided vision at low luminances A. Van Meeteren.

Helmet mounted display system

Abstract: An apparatus for combining a display image with the field of view of a viewer. Light from either a night vision system (14) of a CRT (12) is directed into an eyepiece assembly (18). The eyepiece magnifies and focuses the image into a combiner (30). The combiner (30) consists of an elongated optical element with two parallel sides (36) and (38) and two concave reflective surfaces (32) and (34) at each end. Light entering the combiner (30) is reflected off the first reflective surface (32) and then is reflected back and forth between the sides of the combiner (36) and (38) and then onto the second reflective surface (32). Light reflected off the second reflective surface (32) is combined with light entering from the field of view of the viewer through a prism element (44). The result is that the display image is superimposed in the field of view of the viewer. The system is light in weight, does not protrude significantly from the user's head, introduces minimal distortion and offers a wide field view.

Target illuminators and systems employing same

Abstract: Devices for illuminating a target with a beam of coherent energy. The device has a number of applications. In one, it is employed with a night vision system to make available additional energy which can be utilized by an image intensifier in the night vision system in producing a visual image of a target acquired by the night vision system.

Hand mounted aviation night vision illuminating device

Abstract: Apparatus for illuminating a portion of the cockpit of an aircraft utilizing a night vision imaging system. The apparatus comprising and illumination unit rising an LED for selectively producing a beam of light which will not adversely affect the operation of the night vision imaging system. The illumination unit is arranged to be releasably mounted on the pilot's index finger. The illumination unit includes a pair of depressible switches each of which is arranged to be operated by the pilot's thumb or another finger to cause the unit to produce the light beam. The unit is mounted on the pilot's index finger by a ring formed of a hook and loop fastening system.

Heads up display for night vision goggle

Abstract: Conventional night vision goggles are provided with heads-up display information at the same focus and in the same field of view as the intensified image. The heads-up display information is typically generated by a remotely located cathode ray tube and transferred to the goggles by a fiber optic cable where it is then introduced into one of the eyepieces, which eyepiece is modified to include an image combiner placed inside its outer lens in order to provide substantially the same eye relief and physical dimensions as an unmodified eyepiece. The image combiner is a partially reflective mirror. Additional lenses are provided between the heads-up display and the beam combiner to insure that this additional information is presented to the eye at the same focus as the intensified image.

Human factors and safety considerations of night-vision systems flight using thermal imaging systems

Abstract: Helmet Mounted Systems (HMS) must be lightweight, balanced and compatible with life support and head protection assemblies. This paper discusses the design of one particular HMS, the GEC Ferranti NITE-OP/NIGHTBIRD aviator's Night Vision Goggle (NVG) developed under contracts to the Ministry of Defence for all three services in the United Kingdom (UK) for Rotary Wing and fast jet aircraft. The existing equipment constraints, safety, human factor and optical performance requirements are discussed before the design solution is presented after consideration of these material and manufacturing options.

Portable cockpit light assembly

Abstract: A portable incandescent light assembly having a selectably interposable filter (17) is disclosed. The light assembly is particularly applicable to night vision situations for airplane pilots. The light assembly comprises a housing (13) in which a light source (65) and a filter (17) for filtering out infrared light are located. The light assembly further comprises a mechanism (11) for rotating the filter (17) within the housing (13) between a filtering position in which the filter (17) is disposed across a light output axis and a non-filtering position in which the filter (17) is disposed parallel to the light output axis.

Dynamic Microvillar Cytoskeletons in Arthropod and Squid Photoreceptors

Abstract: The rhabdomerdl microvilli of arthropod photoreceptors transduce light by a biochemical cascade whose end result is an electrical signal [for review, see Minke et al., 19901. Light-transducing domains (rhabdomeres) consist of regular arrays of microvilli whose membranes contain photopigments, which we will generically term rhodopsins for convenience. The shapes of rhabdomeres are critical and must match the properties of the optical systems that channel light to them [for review, see Snyder, 19791. Although a receptor persists throughout the life of an animal, its microvilli are turned over and in some species are dismantled and replaced daily [for review, see Blest, 19881. These busy daily processes can serve to tailor rhabdomeres for the different optical needs of day and night vision. The cytoskeletal architecture and biochemistry of the vertebrate duodenal brush border have been studied intensively [for review, see Louvard, 19891, but the demands made on photoreceptive microvilli are so distinct that they cannot merely be assumed to be brush-border microvilli writ small. Nor do they resemble auditory stereocilia. Notably, the cytoskeletons of brush-border microvilli, of stereocilia and of leech photoreceptors are readily stabilised for electron microscopy by conventional methods of primary fixation, whereas those of arthropod and cephalopod rhabdomeres are labile and difficult to preserve. They can be stabilised by 1) treatments that imply them to be vulnerable to Ca*+-activated cysteine proteases; 2) extremely fast fixation with cold, rapidly penetrating fixatives [el-Gamma1 et al., 19871; or 3) rapid freezing of small tissue samples by a copper block cooled with liquid helium [Tsukita et al., 19881. The last method yields the only data that can be assumed to be substantially free from artifacts. The cytoskeletons within rhabdomeral microvilli of Drosophila, the blowflies Lucilia and Calliphora, the

Fundamental monocular/binocular HMD human factors

Abstract: Five laboratory studies were conducted in order to establish image alignment tolerances for wide field of view monocular/biocular/binocular helmet mounted displays (HMD). Apache Helicopter type production HMD oculars were used by night vision trained pilots in the studies, the results of which underscore the operational advantage of maintaining one dark adapted eye, and quantify the pilots' perceptual sensitivities to display system sources of binocular misalignment.

Scheiner-principle pocket optometer for self evaluation and bio-feedback accommodation training

Abstract: A method and optometer apparatus for measuring the accommodative state of eye of a subject is disclosed. In a preferred embodiment, the optometer apparatus includes: a pinhole aperture plate having a center and a plurality of apertures in the pinhole aperture plate for viewing by the subject's eye; a positive lens disposed near the pinhole aperture plate and having an optical axis coincident with the center of the pinhole aperture plate; and scaled means inclined away from the positive lens for indicating to the subject the accommodative state of the subject's eye in diopters.

Night vision goggle ambient illumination testing

Abstract: A night vision goggle capability evaluation apparatus useful in assessing the degree of illumination present in a proposed NVG operating environment is disclosed The evaluation apparatus includes portable illuminator and detector devices that are battery operated and optionally coupled to the input and output ports of the goggle during both their own calibration and during measurement of the proposed operating environment The disclosed apparatus operates by calibrating the NVG output measuring detector from the saturated and dark output extremes of the NVG system and then using this calibrated detector to measure the output of the NVG system and determine whether is it receiving adequate light for satisfactory performance

Automobile headlamp and rotatable sidelamp of integrated construction and switching circuit for operating same

Abstract: An integrated combination of a headlamp section and a sidelamp section for a vehicle, with the sidelamp section being oriented and rotatable at a predetermined wrap-around side facing angle with respect to the forward lighting direction of the headlamp section. This angle may be typically on the order of 90° so that the sidelamp provides good continuous wrap-around side lighting and good night vision for persons riding in the vehicle or exiting therefrom. The sidelamp section may be operated in response to the turning on and off of the dimmer bulb within the headlamp section or it may be operated independently of the operation of the dimmer bulb by the use of an OR gate logic circuit in combination with an electro-mechanical relay and switch. This circuit is operable for energizing and de-energizing the relay and switch in response to power applied to any one of a plurality of parallel connected inputs of the OR gate logic circuit. In addition, one of these inputs is connected to operate a sidelamp rotational motion control stage for controlling the rotational motion of the sidelamp in both horizontal and vertical planes to thereby provide automatic and instantaneous side lighting for the automobile.

Fluoroborosilicate glass and clad article

Abstract: There are disclosed fluoroborosilicate glasses that are particularly adapted to being drawn with lead silicate core glasses to produce clad glass fibers useful in forming fiber optic bundles to be incorporated in night vision equipment. The cladding glass has a refractive index not over about 1.465 and a coefficient of thermal expansion not over about 80 x 10⁻⁷/°C. The clad fiber has a numerical aperture approximating or equal to one.

C2NVEO advanced FLIR systems performance model

Abstract: Since 1975, the NVL Static Performance Model for thermal Viewing Systems has been the primary tool in government and industry for evaluating thermal imaging system performance. However, advances in thermal imager technology have resulted in FLIR design improvements not specifically included in the NVL Thermal Model. Model development efforts at the U.S. Army Center for Night Vision and Electro-Optics have produced a model that includes features typically found in advanced FLIR systems, in particular sampling and improved vertical resolution. The Advanced FLIR Systems Performance Model (AFSPM) is a documented and validated computer model that predicts noise equivalent temperature, modulation transfer function, and minimum resolvable temperature for many thermal imaging systems.© (1990) COPYRIGHT SPIE--The International Society for Optical Engineering. Downloading of the abstract is permitted for personal use only.

Results of laboratory evaluation of staring arrays

Abstract: This paper will present the results obtained at the Center For Night Vision and Electro-Optics of laboratory measurements of staring array thermal imaging systems. The results that will be reported are a compilation of a number of different systems tested. This data will be utilized not so much as a presentation of system performance but to show the relevance and validity of the tests. It is hoped that through the presentation of this data the thermal imaging community will get a better understanding of both laboratory and field performance of staring array thermal imaging systems.

Reversal of progressive nyctalopia in a patient with Crohn's disease.

Abstract: A 51-year-old man who had undergone several partial bowel resections for Crohn's disease presented with progressively decreased night vision. Electroretinography showed a flat scotopic response and a diminished, delayed photopic response. Measurement of stool fat showed marked fat malabsorption. Treatment with parenteral nutrition, including administration of vitamin A, resulted in marked improvement in the scotopic and photopic response and subjective improvement in his night vision. Patients with malabsorption states should be followed to avoid irreversible visual loss.

Resolution and signal-to-noise measurement of U.S. Army night-vision goggles

Abstract: The ability to quantitatively characterize the performance of night vision goggles (NVG) is being investigated because the present method of resolution evaluation relies on an imprecise, subjective pass/fail judgement by a trained observer viewing a test pattern. Variation in an observer's training, experience, psychological state, decision bias and visual acuity strongly affect his or her decision when required to decide if a marginal pair of goggles passes or fails. The controversy concerning the increase in commercial and military helicopter accidents involving NVG indicates a need to determine if 1) the use of defective or marginal NVG is a contributing factor to the increase in accidents or 2) the apparent correlation between NVG and accidents is simply due to the increased use of NVG in an expanded and inherently more dangerous flight envelope. The U.S. Army TMDE Support Group (USATSG) has developed instrumentation to augment the AN/3895 TS test set that presents high and low light level resolution targets to AN/PVS-5, AN/AVS-6 and AN/PVS-7 NVG. The NVG Resolution Augmentation to the AN/3895 TS presented here can also quantitatively measure image quality of other image producing systems which are normally viewed, adjusted or inspected by a human observer. The NVG Resolution Augmentation features a custom electronic circuit which provides a user-friendly interface between a commercially available CCD camera, monitor and oscilloscope. USATSG's Army Primary Standards Laboratory at the Redstone Arsenal is presently studying the possibility of a new measurement service by investigating various CCD camera/lens combinations in order to characterize a machine vision standard observer. A characterized image analysis system would enable absolute as well as relative measurements of image quality.

Development of the combiner-eyepiece night-vision goggle

Abstract: Conventional 'straightthrough ' nightvision goggles are now in widespread service with many armed forces throughout the world. Though originally designed for ground forces they have been successfully engineered into the airborne environment and are used on both rotary wing and fixed wing aircraft. However, a major disadvantage in the use of this type of NVG, particularly in fast jet applications, is that they obscure the pilots direct view of the Head Up Display. The combiner eyepiece NVGs solves this problem by giving the pilot a direct view of the HUD and cockpit instruments which is optically combined with the intensified image. The cockpit instruments and HUD are ofcourse compatible with the NVG and are invisible to the NVG. The development ofa Combiner eyepiece NVG from initial concept through to production isdiscussed including design considerations, trade offs and enhancements to the operation of the device. The further development of the combiner eyepiece NVG into a fully integrated ejection safe night vision helmet is also described.

Looking without seeing

Abstract: This article tells how having 20/20 vision is not enough. Beyond seeing straignt ahead, a driver must have good peripheral vision as well as depth perception. Night vision is also vital. The dangers of the twilight period are noted. The findings of researchers relating night vision are described. Tips are given relating to traffic safety for drivers.

Use of holographic optical elements in HMDs

Abstract: Holographic Optical Elements (HOEs) are very appropriate for the construction of Helmet Mounted Displays (HilDs). The low weight and the compactness of HOEs allow for a design which meets the mechanical specifications of a helmet much better than a design with classical optical components. The weight of the optical system can be further reduced by using plastic instead of glass substrates as support material for the holograms. If however, the HOEs are recorded in dichromated gelatin, special precautions have to be taken to obtain humidity-resistant HOEs and to ensure tight adhesion of the gelatin to the plastic. Furthermore, the influence of deformations of the substrate material on the image quality has to be considered as well. In order to find solutions for the above mentioned problems, DCG holograms were recorded on the polycarbonate visor of holographic night vision goggles (HNVG). To study the influence of the optical quality of the plastics on the image quality of the HOEs, various recording configurations have been analyzed.

Continuous edgeline on nine-metre-wide two-lane roads

Abstract: A two-lane road having a width of 9 metres was repaved, the lanes widened and painted with 20 cm wide, continuous edgelines instead of the conventional 10 cm wide intermittent lines. Compared with conventional repavement and repainting, the continuous edgeline was observed to give a larger variation of lateral position and lower speeds. The result should be a reduced risk of rutting. Because the area of the continuous edgeline is larger than that of the conventional line, visual guidance in night-time traffic will be improved. Road user interviews showed that the majority prefer continuous edgelines to intermittent lines. The conclusion drawn is that the wide, continuous edgeline is preferable and should replace the narrow intermittent line. (Author/TRRL)

Laser Protection with Image Intensifier Night Vision Devices

Abstract: : Current military ranging and targeting technology employs high power laser systems Since coherent (laser) energy with wavelengths in the visible and near infrared can seriously damage the retina of the eye, laser retinal injury has been the subject of many studies The results of these investigations are used by various agencies to recommend laser eye protection In the aviation community, since laser protective helmet visors are not compatible with most common night vision devices (NVDs), ie, AN/PVS-5 Night Vision Goggle (NVG) and Aviator's Night Vision Imaging System (ANVIS), the only laser protection currently afforded the NVD aviator is a barrier-type protection provided by the device Based on eye anatomy and function, three retinal regions have been identified as critical to protect - fovea, macula and peripapillary zone (1 to 2 degree annulus surrounding the optic disc) When full-coverage laser protection is not possible, minimum acceptable coverage must include these regions A circular area which includes the critical regions would cover the central retina, ie, area out to 25 degrees from the visual axis

Evaluation of Night Vision Goggles for Maritime Search and Rescue. Volume 1. Techniical Report

Abstract: : Three experiments were conducted during 1989 by the U.S. Coast Guard Research and Development (R&D) Center to evaluate night vision goggles (NVGs) for their effectiveness in detecting small targets at night. Three types of NVGs were evaluated: the AN/AVS-6 Aviators Night Vision Imaging System (ANVIS) NVG was tested onboard Coast Guard HH-3 and CH-3 helicopters, and the AN/PVS-5C and AN/PVS-7A NVGs were tested onboard 41-foot Coast Guard utility boats (UTBs). Simulated persons in the water (PIWs), 4- and 6-person life rafts, 18- and 21- foot white boats, and white, personal flotation device (PFD) strobe lights were employed as targets during realistically-simulated search missions. A total of 1,490 target detection opportunities were generated during the experiments. These data were analyzed to determine which of 25 search parameters of interest exerted a statistically-significant influence on target detection probability. (JS)

Splittable and reconfigurable episcopic sighting telescope

Abstract: The subject of the invention is an episcopic sighting telescope for day and night observation and firing on a vehicle fitted with a gun. … It comprises a set of interchangeable modules grouping the optical elements, constituted in particular by a head module 1 housing a mirror controlled in elevation, a raising module 2, a day vision module 4, a night vision module 5, a telemetry module 6 and an electronic unit coupled with a firing computer 8. It comprises a module 3 for separating the day and night channels interposed between the raising module 2 and the day and night modules 4, 5 housing means of generating a sighting reticle in the day and night channels. The means of generating a firing reticle comprise a collimator for projecting this reticle and a rhombohedron for injecting this reticle in the day and night modules. … Application to weapon systems. … …

Night Vision and Night Vision Goggles

Abstract: : Night Vision Goggles (NVG) do not turn night into day. In fact, they have limited performance capability. This articles addresses the rationale for low light operations, how NVGs work, and various NVG limitations. Knowledge of the NVG performance envelope, inherent NVG limitations, effects of human vision deficiencies, and factors of self-imposed stress, constitute the formula for determining safe maneuver limits. The article concludes with recommendations to improve NVG use and affirms that NVG are safe for helicopter operations.

Development of an aviator's helmet-mounted night-vision goggle system

Abstract: Helmet Mounted Systems (HMS) must be lightweight, balanced and compatible with life support and head protection assemblies. This paper discusses the design of one particular HMS, the GEC Ferranti NITE-OP/NIGHTBIRD aviator's Night Vision Goggle (NVG) developed under contracts to the Ministry of Defence for all three services in the United Kingdom (UK) for Rotary Wing and fast jet aircraft. The existing equipment constraints, safety, human factor and optical performance requirements are discussed before the design solution is presented after consideration of these material and manufacturing options.

Evaluation of Night Vision Goggles for Maritime Search and Rescue

Abstract: : Three experiments were conducted during 1989 and two more have been conducted during 1990 by the U.S. Coast Guard Research and Development (R&D) center to evaluate night vision goggles (NVGs) for their effectiveness in detecting small targets at night. Three types of NVGs were evaluated: the AN/ AVS-6 Aviators Night Vision Imaging System (ANVIS) NVG was tested onboard Coast Guard HH-3 and CH-3 helicopters, and the AN/PVS-5C and AN/PVS-7A NVGs were tested onboard 41-foot Coast Guard utility boats (UTBs). During the Fall 1990 experiment, 4-and 6-person unlit life rafts, with and without retro-reflective tape and 18-and 21-foot white boats were employed as targets during realistically-simulated search missions and are discussed herein. A large quantity of well moonlit data were collected during the fall 1990 experiment and this third interim report discusses target types where new information was obtained. A total of 1,612 target detection opportunities were generated for the above-mentioned target types during the five experiments. These data were analyzed to determine which of 25 search parameters of interest exerted a statistically-significant influence on target detection probability. Lateral range curves and sweep width estimates are developed for each search unit/target type combination. Human factors data are presented and discussed. Recommendations for conducting NVG searches for small targets and for additional data collection and analysis are provided.