Showing papers on "Night vision published in 1972"

Retinal Metabolism in Dark and Light

Abstract: One may expect to find in this concluding chapter on metabolism an account for the expenses incurred by the retina in the performance of the activities outlined in the preceding contributions to this volume. Information on its source and its fate — as a building block or fuel — should provide some insight in the inner workings, from which eventually a rationale may be derived for the beneficial intervention in the repair or even improvement of visual function, as perhaps in night vision. The uses of the substrate under specified load may serve to substantiate the powering of amplifier actions invoked in many guises, providing gain, feedback, preventing contamination of the visual signal to be processed, etc. The kinetics of metabolic reactions may help to determine which of a number of processes is the deciding one, e.g. during restoration of sensitivity after exposure to light. Or, the measured rate of metabolism could substitute for “neural work”, a quantity not otherwise available at present.

Testing tool for determining the boresight retention of weapons brackets and night vision sights

Abstract: A testing tool that includes a light weight, highly accurate telescope and supplemental weights used to duplicate the weights of various night vision sights. The testing tool is mounted on a weapons adapter bracket for testing the accuracy of either or both the sight and the bracket. The supplemental weights include a main body block and auxiliary side weights in which the auxiliary side weights are bolted traversely through the main body block. The telescope is connected to one side of the main body block. The side of the main body block opposite the telescope is bottomed out on the bottom and beveled edges of a rectangular channel in a weapons adapter bracket. The weapons adapter bracket is connected to a weapon.

Effect of marihuana on the visual autokinetic phenomenon.

Abstract: THE EFFECTS OF FOUR DOSE LEVELS OF MARIHUANA UPON THE VISUAL AUTOKINETIC PHENOMENON WERE EXAMINED IN 12 SS. THE AMOUNT OF APPARENT MOVEMENT WAS GREATLY INCREASED UNDER THE TWO HIGHEST DOSES. POSSIBLE HAZARDS ASSOCIATED WITH VEHICLE OPERATION AT NIGHT UNDER MARIHUANA ARE NOTED. /AUTHOR/

Human visual response to nuclear particle exposures

Abstract: Experiments with accelerated helium ions were performed in an effort to localize the site of initial radiation interactions in the eye that lead to light flash observations by astronauts during spaceflight. The character and efficiency of helium ion induction of visual sensations depended on the state of dark adaptation of the retina; also, the same events were seen with different efficiencies and details when particle flux density changed. It was concluded that fast particles cause interactions in the retina, particularly in the receptor layer, and thus give rise to the sensations of light flashes, streaks, and supernovae.

The Theory and Measurement of the Signal-to-noise Ratio of Second Generation Image Intensifiers

Abstract: The measurement of the signal-to-noise ratio (S/N) for use in the comparison and specification of image intensifier tubes is a relatively new process. Night Vision Laboratory, Fort Belvoir, Virginia, introduced the measurement 2 years ago as a specification for image tubes used in advanced image intensifier systems. Since that time much work has been done to improve the accuracy of the measurement, but further refinements are possible. The theory defining system performance as a function of S/N has also been studied in a qualitative fashion and much remains to be done to incorporate S/N as a parameter for the prediction of system performance. This paper presents a theory which outlines the basic nature of S/N as a function of light level, tube parameters, and bandpass. Furthermore, an advanced digital measurement technique is described which greatly simplifies the measurement of S/N and bypasses problems inherent in other measurement systems.

A solid-state infrared image converter

Abstract: A photoconductor-electroluminescent type infrared image converter panel has been studied through the application of doped CdSe photoconductive powder layers of different thickness to the earlier type of image converter and through temperature operation. The spectral sensitivity extended from 0.7 to 1.2 µm with sensitivity peak at 0.9 µm and the minimum detectable input power density reached approximately 2×10-10W/cm2for 0.9 µm at 0°C. Projected infrared images are converted to visible electroluminescent images with a resolution of 3 to 8 TV lines/mm and a response time of an order of 1 to 10-2s, depending upon the photoconductor thickness and the operating temperature. The converter panel may be used as a night vision panel with an additional infrared source. This paper describes a preparation of doped CdSe photoconductor suitable for a photoconductor-electroluminescent device, some of its properties, and the effect of the photoconductor thickness and of the operating temperature on the performance of the solid-state infrared image converter. Converted visible images using experimental panels are also shown.

Monocular and binocular visual ability in nocturnal driving visibility.

Abstract: BINOCULAR AND MONOCULAR VISION AT NIGHT WERE STUDIED WITH THE AMERICAN AUTOMOBILE ASSOCIATION NIGHT SIGHT METER. NINETY-SIX SUBJECTS WERE TESTED FOR GLARE VISION, NIGHT VISION AND RECOVERY TIME. NO DIFFERENCES EXIST BETWEEN MONOCULAR AND BINOCULAR NOCTURNAL VISIBILITY. THE INSTRUMENT ITSELF MAY ONLY BE VALID AS A MEASURE OF RECOVERY TIME FROM GLARE.

Ocular Hazard of the GaAs Laser

Abstract: : The GaAs laser is used in intrusion alarm systems, secure communication links, and short distance range-finders. By use of multiple diode arrays, high average power visually covert illumination is possible for night vision and range gated systems. Each of these applications exposes human eyes to GaAs laser radiation, and thus it is necessary to determine the ocular hazard of these lasers. An experimental determination is reported of the damage threshold of ocular damage using a GaAs laser.

Alcohol and Disorientation-Related Responses. VI. Effects of Alcohol on Eye Movements and Tracking Performance During Laboratory Angular Accelerations about the Yaw and Pitch Axes,

Abstract: : Alcohol ingestion interferes with visual control of vestibular eye movements and thereby produces significant decrements in performance at a compensatory tracking task during oscillation about the yaw axis; significant or consistent decrements in performance in the absence of motion were not obtained. The present study was designed to extend knowledge about these effects to pitch-plane stimulation. Alcohol doses were 2.0 ml of Smirnoff vodka per kg of body weight and tests were conducted before drinking and one, two, and four hours after drinking. In the absence of motion, there was no difference between the groups in tracking error while subjects were in the pitch position; significantly more errors occurred for alcohol subjects in the yaw position one and four hours (but not two hours) after drinking. During motion, one and two hours after drinking, alcohol subjects performed significantly poorer than the non-drinkers and had significantly less control of their eye movements for both axes of stimulation. Absolute error was greater during all sessions for pitch-plane stimulation as compared with yaw-plane stimulation. These degrading effects of alcohol on performance, particularly evident during motion, are discussed from the viewpoint of aviation safety. (Modified author abstract)

Development of Variable Affinity Barrier Photoemitter

Abstract: : This research and development program was directed toward establishing the feasibility of fabricating high quantum efficiency photo emitters based on the Variable Affinity Barrier (VAB). Although extreme fabrication difficulties were encountered, which necessitated radical changes in emitter designs, a few samples did exhibit electron emission. However, these samples were short lived and photo emissive measurements could not be conducted. In all, three different design approaches were investigated. These were: (1) Fabricating VAB junctions using single crystal p type silicon, (2) Fabricating VAB junctions using epitaxial p on p+ silicon, and (3) Fabricating VAB junctions using a tin oxide film on p type silicon. Only the last approach was partially successful--emission occurred. However, the results do not preclude that the other two design approaches are unfeasible, but only that during this program it was not possible to fabricate the necessary geometries or heterojunctions.

Visionics Night Vision Goggle Study.

Abstract: : 7026(*NIGHT WARFARE, *EYEGLASSES), EFFECTIVENESS, NIGHT VISION, COMBAT SURVEILLANCE, SPECIFICATIONS, SIMULATORS, TEST METHODS, RELIABILITY*GOGGLES, *NIGHT VISION, NIGHT DRIVINGThe present report addresses the overall utility of the night vision goggles. Military effectiveness of the goggles over the unaided eye for night driving, close-order operations, patrol, and combat surveillance was evaluated by field experimentation. Identification of optical, electro-optical, and human-related factors was done through laboratory simulation and bench-test evaluations. Alternative approaches, as well as electro-optical specifications for individual night vision aides, were considered and evaluated. The 40 degrees FOV Night Vision Goggles provide a dual (passive-active), open-hatch, night-driving capability for armored vehicles. (Author Modified Abstract)

Effects of STANO Sensors on Small Unit Effectiveness. Part I

Abstract: : Continuing research is being conducted by the Behavior and Systems Research Laboratory in the STANO Performance Optimization Program (formerly Night Operations) directed toward enhancement of combat soldier performance in night operations utilizing night vision devices and related sensors. Eighteen squads were tested on each of three mixes (with three sensors per mix) for two tactical deployments of the sensors. For each mix a total of 144 targets were presented under starlight, a total of 72 targets under moonlight. Sensors employed included the Starlight Scope, AN/PVS-2 (SS), Listening Post Surveillance Device, AN/PPS-14 (PPS-14), Patrol Seismic Intrusion Device, AN/GSQ-151 (PSID), and Hand-Held Thermal Viewer, AN/PAS-7 (HHTV). Results showed that a higher quality of target information is obtained with the mix containing one PSID, one SS, and one HHTV than with the other mixes tested. All mixes showed a substantial loss of information as reports were transmitted from squad leader to platoon leader, particularly with regard to quality of information. Under high illumination, quality of performance improved for mixes containing a Starlight Scope. The number of false reports was small for all sensors and mixes, but was higher for the HHTV than for the other sensors. Results strongly suggest the need for improved procedures of more adequate training, or both.

Seeing in the dark

Abstract: A survey of the current state-of-the-art in night vision technology is presented, including both direct vision and low light-level television systems. Possible developments in thermal imaging techniques are discussed.

A Quantitative Performance Measure for Night Vision

Abstract: (1972). A Quantitative Performance Measure for Night Vision. Optica Acta: International Journal of Optics: Vol. 19, No. 5, pp. 409-411.

Transitional adaptation in tunnel lighting

Abstract: THE PHENOMENON OF TRANSITIONAL ADAPTATION CONCERNS CHANGES IN VISIBILITY RESULTING FROM SUDDEN INCREASES AND DECREASES IN THE PREVAILING LUMINANCE LEVEL OF THE VISUAL FIELD. SUDDEN TRANSITIONS IN TUNNEL LIGHTING ARE ABLE TO PRODUCE A "BLACK-OUT" EFFECT AT THE ENTRANCE OF A TUNNEL, CREATE BLIND SPOTS AT BOTH ENTRANCES AND EXITS, AND REDUCE TRAFFIC SPEED THROUGH THE TUNNEL. IN ADDITION, DISCONTINUOUS OR SPACED LIGHTING FIXTURES WITHIN A TUNNEL MAY PRODUCE A FLICKERING EFFECT THAT CAN ALSO REQUIRE TRANSITIONAL ADAPTATION. WHEN THE EYE IS PRESENTED WITH A SUDDEN INCREASE OR DECREASE IN THE PREVAILING LEVEL OF ILLUMINATION, A TRANSIENT BURST OF ACTIVITY OCCURS IN THE RETINA WHICH IS TRANSMITTED TO THE BRAIN, SIGNALLING THIS CHANGE. IF THE INDIVIDUAL IS ASKED TO PERFORM A VISUAL TASK AT THIS TIME, A GREATER CONTRAST BETWEEN THE VISUAL STIMULUS AND ITS BACKGROUND WILL BE REQUIRED, BECAUSE THE VISUAL SYSTEM IS BUSY HANDLING INFORMATION RELATED TO THE CHANGE IN LUMINANCE LEVEL. EXPERIMENTS HAVE BEEN CONDUCTED AT THE UNIVERSITY OF ROCHESTER AND THE UNIVERSITY OF VIRGINIA TO SIMULATE THIS PHENOMENON UNDER TYPICAL DRIVING CONDITIONS, SUCH AS DRIVING IN TUNNELS OR AT NIGHT. THE EXPERIMENTS ARE DESCRIBED, AND THEIR RELEVANCE FOR THE DESIGN OF HIGHWAY LIGHTING SYSTEMS IS TREATED BRIEFLY.