Showing papers on "Night vision published in 1987"

Light and Electron Microscopic Observations of Mitochondrial Fusion in Plasmodia Induced Sporulation in Physarum polycephalum

Abstract: The morphological behavior of cell nuclei, mitochondria and mitochondrial nuclei during sporulation in Physarum polycephalum was investigated using light and electron microscopy. The plasmodia which reactivated from sclerotia on non-nutrient agar plates preferentially entered into sporulation. A night vision camera and time lapse VTR were available to monitor morphological changes and determine the exact time course. Sporulation processes were classified into six stages, by morphological characteristics. The initial event of sporulation was characterized by the formation of many protoplasmic knobs along plasmodium strands (protoplasmic balling stage). A papilla was projected from the apical region of each protoplasmic knob, elongated and changed to form a stalk (stalk elongation stage). The apical part of the stalk then began to expand until it reached a maximum point of stalk elongation, thereafter differentiating into the head of the sporangium (head expanding stage). After a stage without morphological changes (resting stage), the color of the sporangial head gradually changed from pale yellow to black (head blackening stage). After full blackening of the sporangial head, sporangia were completed (mature stage). 4'6-diamidino-2-phenylindole (DAPI) epifluorescence microspectrophotometry showed that the cell nuclear DNA content in sclerotia and starved plasmodia before the resting stage was the same as that in somatic diploid G2 phase nuclei. Only a single somatic nuclear division occurred at mid-resting stage. Meiotic DNA synthesis then occurred during the late resting and head blackening stages, when cytoplasmic cleavages occurred. After DNA synthesis, cell nuclei persisted in a long G2 phase of about one day and stopped at meiotic prophase I. In sclerotia and starved plasmodia, mitochondria were spherical or oval and contained one electron-dense mitochondrial nucleus (mtnucleus). Mitochondria and mt-nucleus became smaller in size in starved plasmodia. The DNA content per mitochondrial nucleus at that time was reduced by half as compared with that at the early starved plasmodium stage. Dumbbell-shaped mitochondria appeared during the resting stage; these had two mt-nuclei, each located discretely at either side of the dumbbell-shaped mitochondrion. Mitochondria containing 3-6 nuclei were also observed, at low frequency; multinucleated mitochondria persisted up to meiotic prophase I. The mitochondria in amoebae which originated from spores contained only one mt-nucleus. These results indicate that mitochondrial nuclear fusion occurs at some stage between spore germination and the amoeba stage, following mitochondrial fusion at the resting stage of sporulation in Physarum polycephalum.

Training Needs Assessment and Training Technology Transfer in U.S. Army Europe (USAREUR): 1985

Abstract: : Armor and Infantry training information needs identified by U.S. Army Europe (USAREUR) training managers are presented. Efforts to respond to these needs with existing ARI products are discussed. Transfer of emerging training products from the ARI Work Program to USAREUR for review is described. Several training devices programs currently being previewed for USAREUR input are presented. Keywords: Army training, Gunnery trainers, Tracked vehicles, Maneuvers, Maintenance training, Rifle marksmanship, Night vision, Drivers(Personnel).

Progressive cone dystrophy.

Abstract: Psychophysical, reflectometric, and electrophysiological studies were performed on four members of a dominant pedigree with progressive cone dystrophy. The two youngest individuals were asymptomatic at the initial examination, and none of the subjects complained of problems associated with night vision. Absent or grossly reduced cone-mediated ERG responses revealed the widespread loss of cone function. Moderate elevations (1 log unit) in absolute threshold together with reductions in rhodopsin levels in the midperipheral retina provided evidence of a mild impairment of the rod system also, although not to the degree seen in a cone-rod dystrophy. The progressive nature of the disease was apparent from the case histories and the changes in visual performance that occurred on re-test after a 5-year interval. Likewise, the results of incremental threshold measurements at several retinal loci suggested that peripheral cones may be affected earlier and more severely than those in the central retina.

Universal passive night vision system

Abstract: A method and apparatus for arranging primary optical apparatus to provide a high degree of adaptability to other vision equipment. The primary optical apparatus (10) includes a housing (90) with a number of cavities for holding optical components in alignment with respect to various optical paths. An image intensifier tube (114) is mounted in a cavity (112) disposed in a planar face (70) of the housing (90). The planar face (70) is adapted for mounting to a variety of other optical equipment. A collimator (115) is disposed in a housing cavity (113) and optically aligned between the tube (114) and a dual prism (128, 136). The optical images existing the prisms (128, 136) are redirected through turning mirrors (154, 158) and presented through eyepieces (92) to an observer.

High light level cutoff apparatus for use with night vision devices

Abstract: There is disclosed a high light level cutoff apparatus for use with night vision devices. The apparatus employs a digital method of timing implemented by a divider counter responsive to a crystal controlled input frequency which essentially controls a latch to produce an automatic shutoff of a night vision device during high light ambient conditions which conditions would undesirably reduce the effective life of such a night vision device. The circuitry disclosed utilizes a digital method of clocking and employs the latching relay as indicated which is operated by the digital counter. The circuitry provides a feed back from the latching relay which resets the night vision system so that it will re-operate if a transient accidentally serves to operate the goggles while the light level is in a high state. The circuitry provides a precise timing level via the counter which can be selected to provide extended time out periods from milliseconds to at least several minutes, circumventing many of the disadvantages of prior art devices.

Hermetic, vacuum and pressure tight electrical feedthru

Abstract: A vacuum tight electrical feedthru is disclosed for use where electrical leads must pass through the walls of a container in which a high vacuum must be maintained It is useful in conjunction with infrared sensors, as well as for security, fire detection, rescue, night vision and medical applications The feedthru includes a ceramic circuit ring with electrical traces deposited on one side A ceramic seal ring partially covers the traces and is fired down to the main ceramic ring forming a hermetic seal Metal rings are brazed to the seal ring and the ceramic circuit ring to allow welding to a housing Spring loaded pads load a resilient pad onto the cables forcing gold plated dots to make contact to the pads on the ceramic circuit ring This feedthru provides 180 conductors, 90 on each side The ribbon cables are etched to expose the wires, which are then pressed on the gold dots

Digital Simulation Of Precise Sensor Degradations Including Non-Linearities And Shift Variance

Abstract: Invited PaperDigital Simulation of Precise Sensor DegradationsIncluding Non -Linearities and Shift VarianceGertrude H. KornfeldVisionics Division, Center for Night Vision and Electro- Optics,Fort Belvoir, Virginia 22060 -5677AbstractRealistic atmospheric and Forward Looking Infrared Radiometer (FLIR) degradations weredigitally simulated. Inputs to the routine are environmental observables and the FLIRspecifications. It was possible to achieve realism in the thermal domain within accept-able computer time and random access memory (RAM) requirements because a shift variantrecursive convolution algorithm that well describes thermal properties was invented andbecause each picture element (pixel) has radiative temperature, a materials parameter andrange and altitude information. The computer generation steps start with the image syn-thesis of an undegraded scene. Atmospheric and sensor degradation follow. The finalresult is a realistic representation of an image seen on the display of a specific FLIR.IntroductionAutomatic Target Recognizer (ATR) and human observer tests require a large set ofthermal imagery that must be gathered under a wide variety of environmental conditions.It is cost effective to augment a field tests data base with computer generated imagery,provided sufficient realism in the thermal domain can be achieved.For this purpose the creation of a computer generated data base was started.

Hybrid perimetry: a blend of static and kinetic techniques

Abstract: A new hybrid perimetry technique is proposed that combines elements of kinetic and static methods. The stimulus is presented in stationary flashes, as in static perimetry, but successive flashes are moved progressively across the retina to map isopters, as in kinetic perimetry. Tests with a Tubingen perimeter show that the three methods provide similar estimates of sensitivity and variability for normal subjects. The hybrid method requires about the same time to determine an isopter point as the static method requires to determine a threshold. However, the hybrid method tests a larger retinal area in that time than the static method while providing an isopter measurement that is free of the reaction time artifacts characteristic of the kinetic method. Comparisons of photopic and scotopic hybrid fields show that one well-chosen scotopic isopter can provide as much information as three photopic isopters.

Scotopic Sensitivity with 10% Oxygen

Abstract: : The night vision (scotopic) sensitivity of 6 subjects was measured while they were breathing either air (21% oxygen, PO2 160 torr) or 10% oxygen, balance nitrogen (PO2) 76 torr Continuous monitoring showed that the mean oxygen content in the arterial blood (SaO2) dropped from 97% to 77% during the first seven minutes of breathing 10% oxygen, and there was a significant degradation of scotopic sensitivity The reduced sensitivity was attributed solely to hypoxia with no contribution from hypocapnia Keywords: Scotopic sensitivity; Hypoxia; Hypocapnia

Extending the CNVEO Search Model to the Multitarget Environment.

Abstract: : This paper develops a multitarget acquisition model as an extension of the single-target acquisition model of the Army's Center for Night Vision and Electro-Optics. The paper then outlines the implementation of the multitarget acquisition model in battlefield combat simulations. Finally, the paper suggests how the model may be used to simulate field tests accurately and how some simple experiments can validate the model.

Airborne Minefield Detection And Reconnaissance System (AMIDARS)

Abstract: Rapid, real-time reconnaissance of a large ground area is critical for the commander on the battlefield. It provides him with the ability to gather valuable knowledge of troop and armor movement, and tactical intelligence in any direction in a matter of minutes instead of days. A passive infrared line scanner which covers a large area in a short time will provide this effective tactical reconnaissance in the battlefield. The Airborne Minefield Detection and Reconnaissance System (AMIDARS) has been built by CAI, a Division of RECON/OPTICAL, INC., under contract to the CECOM Center for Night Vision and Electro-Optics, to meet this need. The AMIDARS Infrared Line Scan-ner (IRLS) provides three-axis stabilized, real-time, day/night imagery with a 120° Field of View (FOV). This paper discusses the essential features of the AMIDARS sensor design.

Turning night into day

Abstract: Front-line military aircraft today are an expensive commodity. Integrated night vision systems, using forward-looking infra red (FLIR) can double aircraft utilisation by providing the pilot with an image of the terrain ahead, enabling navigation and ground attack in poor visibility and total darkness

IR Emitting CRT

Abstract: This paper describes efforts undertaken at the U.S. Army Center for Night Vision and Electro-Optics to produce a mid and far infra-red emitting cathode ray tube. The background of this research effort is explained and the products and by-products are described along with their status and expected applications.

Helmet Mounted Display For Tank Applications

Abstract: A prototype remote helmet mounted display (HMD) has been demonstrated on a combat vehicle as a display for the tank commander. Preliminary tests indicated that the HMD did improve communications and coordination with the other crewmen, providing the tank commander with more control over the tank. In addition, several new options are now available to the combat vehicle community which were not possible in the past. If the HMD were utilized with a stabilized platform, the expanded capability could enhance and change the role of combat vehicles.

Optical scanning device

Abstract: This device ensures the optical scanning of a field of view in two perpendicular directions termed line and frame. The device ensures the convergence of the optical beams emanating from the various zones of the field on a sensitive element. The line scanning means include a fixed toric mirror which is axisymmetric about the axis of rotation of the said line scanning means forming an image of the sensitive element on the said axis of rotation. According to the invention, this mirror is formed of two parts each belonging to the concave surface of a paraboloid, the axes and vertices of the two paraboloids being situated on the said axis of rotation or respectively on the said axis and another axis which is perpendicular to it. Application to night vision.

Cockpit readiness for night vision goggles

Abstract: The introduction of night vision goggles into the cockpit environment may produce incompatibility with existing cockpit optoelectronic instrumentation. The methodology used to identify the origin of the spurious signal is demonstrated with the example of an electronic display. The amount of radiation emitted by a gray body in the wavelength region of goggle sensitivity is calculated. A simple procedure for preflight testing of cockpit instrumentation using a commercially available infrared camera is recommended. Other recommendations include the specification of cocklpit instrumentation for compatibility with night vision devices.

Thermal Modeling And IR Scene Generation

Abstract: Thermal Modeling and IR Scene GenerationRandy K. ScogginsUS Army Engineer Waterways Experiment StationAbstractThe Waterways Experiment Station (WES) has for several years been engaged in the devel-opment of numerical models for the simulation of terrain surface temperatures. Models havebeen developed to describe major components of the earth's surface such as grasslands,lands essentially bare of vegetation, such as deserts, and forested areas. These modelscombine first principles and semi -empirical techniques and use local surface meteorologyand material thermal properties for input. Recently, WES has begun work on using thesemodels to provide terrain radiance information needed for production of realistic computergenerated infrared (IR) images. The approaches used in terrain temperature modeling arediscussed, along with the structuring of the codes in a form amenable to scene generationrequirements. Data needed by the models are outlined, and model predictions are comparedto measured temperatures. Various approaches to account for the effects of atmosphericcontaminants which may be applied to computer scene simulation are presented. Computertexture generation techniques based on thermal modeling as applied at WES are outlined.Application of models in an IR scene generation computer code developed by WES is discussedand example imagery presented. Possible extension of current work to other spectralregions and additional efforts for increased realism are also discussed along with possibleapproaches.IntroductionCreation of images by computers using computer data bases has for many years been anarea of intense study. Generally, the reason for scene generation by computers is to 'see'the terrain or object of interest in ways and under conditions difficult or impossible toobtain in any other manner. Much has been accomplished in the production of views simu-lating visible light sensors. Interest has increased in using computers to simulate imagesas would be seen by multispectral systems, primarily near and far IR, such as the work byKornfeld of the Army's Center for Night Vision and Electro Optics (Kornfeld 1985).The US Army Engineer Waterways Experiment Station has begun a program to simulate ther-mal (8 to 14 micrometer) images of major surface types such as agriculture, forest, andgrassland. Mean gray levels for these terrain backgrounds are estimated by a set of com-puter models developed for WES. These models use terrain and environmental data as well asparameters describing specific terrain type materials to calculate temperatures of terrainbackgrounds. Temperatures are related to mean radiance and thus to mean gray level. Vari-ation about the mean gray level is accomplished by a terrain -dependent formula using stan-dard deviations and correlation lengths specific to terrain types. A similar approach isused for structures such as buildings and roadways. Computer- created structure scenes arethen inserted into a complex background scene to produce the final result.Background Surface Temperature ModelsThree fundamental temperature modeling codes for estimating surface temperatures ofmajor terrain components have been developed by WES. Each model makes temperature predic-tions for a basic class of terrain (bare soil, vegetation, etc.). These computer modelsrequire as input the geometric and thermophysical properties of the materials being modeledas well as standard meteorological data representing the time frame of interest. Outputconsists of physical and radiometric temperatures as a function of time for each area beingmodeled. More advanced components of the models modify radiometric temperature predictionsto account for surface roughness and view angle. The initial versions of the programs werecompleted in 1981; since then, several modifications and extensions have been made, andupdates are being integrated into the software to improve the performance of the models.Modifications have also been made to the codes so that temperature predictions for all com-binations of basic surface terrain types and orientations are produced automatically andoutput in a form compatible with the scene generator software.Bare terrain surface temperature modelA first -principles model was developed to calculate surface temperature for nonvegetatedsurfaces (e.g., plowed fields, deserts) by performing an energy budget analysis of the ter-rain surface (Balick et al. 1981). Each major component of energy exchange between thesurface plane (which is assumed to be infinitely thin), the subsurface materials, and the50 /

The Development and Evaluation of Advanced Rifle Marksmanship Training Programs with the M16 Rifle

Abstract: : In May 1987 a research effort that examined current Advanced Rifle Marksmanship (ARM) training conducted during One Station Unit Training (OSUT) at Fort Benning, georgia, was initiated. This research evaluated night fire with no illumination, normally scheduled night fire training with artificial illumination, and protective mask fire during daylight. Alternative methods of training were tested in addition to night fire training using the AN/PVS-4 night vision sight. Separate alternative training methods were tested for protective mask fire during daylight. All training procedures developed during this effort used existing range facilities and training resources. Additional resource demands were confined to increases in training time allocation and extra ammunition. Findings indicated that soldiers had extreme difficulty in hitting targets during night fire with no illumination and with artificial illumination. Results for night fire using the AN/PVS-4 night vision sight showed that soldiers were capable of hitting targets out to 300 m. Findings for protective mask fire during daylight also indicated that soldiers were capable of hitting targets out to 300 m.

Infrared Activities In The Netherlands

Abstract: This presentation summarizes the infrared activities in the Netherlands during the past 30 years and indicates the directions for future work. The capabilities of infrared technology, being passive and useful for night vision applications were envisaged for a long time in our country. The dependence on the military market however made the progress slow, but this time was used properly by the research scientists to fully explore the problem areas. The main topics are IR signature work, IR backgrounds, IR measuring equipment, propagation studies, civil IR work, sensor studies, IR countermeasures, and same new directions.

The Accommodative Status in the Dark of U.S. Navy Fighter Pilots.

Abstract: : Visual accommodation of 172 naval aviators in the dark was measured and compared to their most recent night carrier landing scores and the average distance at which an adversary aircraft was first sighted during air combat maneuver training No significant correlations were found between the accommodation measures and either measure of operational performance Reasons for this result are discussed Accommodation measures in the aviator sample in the dark are compared to measures made in samples of college students reported in the literature The aviator sample is significantly less myopic than the student sample For example, only 6% of the students have as little myopia as the average naval aviator This dramatic difference in accommodation could result from either training or some set of selection factors Possible reasons for this finding and its significance for the Navy are discussed

Photoemission of Pd-Ag-O-Cs and Sb-Na−K-Cs photocathodes under the illumination of clear star radiation

Abstract: The photoemission of Pd-Ag-O-Cz and Sb-Na-K-Cs photocathodes under the illumination of clear star radiation are calculated and compared. From the calculated results, it gives a prospect that the Pd−Ag−O−Cs photocathode may be used in image intensifier as passive night vision instruments.

Characterization Measurements Of Holographic Mirrors

Abstract: This paper examines holographic mirrors used in Holographic Night Vision Goggles (HNVG). The characteristics of the DOEs such as diffraction efficiency, spectral bandwidth and homogeneity have been investigated experimentally. These performances have been tested in a geometry which simulates as close as possible the operating conditions of the HNVG. The advantages of this approach are discussed in comparision with the commonly used technique of characterization.

Range Prediction Of Image Intensifier Tube Based Night Vision Devices And Improving Capability By Filtering Technique

Abstract: Range performance of Image Intensifier (II) tube based night vision devices depends upon the output image contrast which in turn depends on the scene integral spectral contrast, loss of contrast due to atmospheric attenuation and finally the Modulation Transfer Function (MTF) of the system.