Download or read book Comparative Night Vision Goggle Visual Acuity Measurements Performed in the A 10 Aircraft in an Operational Setting written by and published by . This book was released on 1993 with total page 29 pages. Available in PDF, EPUB and Kindle. Book excerpt: The Night Vision Programs Office of the Aircrew Training Research Division, Armstrong Laboratory, responded to a request from the 422nd Operational Test Squadron at Nellis AFB to conduct the ground testing portion of their A-10 Night Vision Goggle (NVG) special project. Evaluations were conducted comparing the performance of four different NVGs under both laboratory and representative operational conditions. The performance of the F4949 'Super ANVIS' was superior to that of the other NVGs tested. Additionally, a comparative study was conducted evaluating the impact of two different windscreens on NVG image quality. The new windscreen allowed the transmission of more energy usable to the NVGS, thus enhancing image quality over that possible with the old windscreen ... Adjustment procedures, Night vision goggles, Transmissivity, Compatible cockpit lighting, NVD, Visual acuity, Night vision devices, NVG.
Download or read book Scientific and Technical Aerospace Reports written by and published by . This book was released on 1995 with total page 702 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book Monthly Catalog of United States Government Publications written by and published by . This book was released on 1994 with total page pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book Monthly Catalogue United States Public Documents written by and published by . This book was released on 1994 with total page 752 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book Government Reports Annual Index written by and published by . This book was released on 1993 with total page 1452 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book Government Reports Announcements Index written by and published by . This book was released on 1996 with total page 948 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book Night Vision Goggle Field expedient Visual Acuity Adjustment Procedures written by and published by . This book was released on 1996 with total page 54 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book Comparative Visual Performance with ANVIS Aviator s Night Vision Imaging System and AN PVS 5A Night Vision Goggles Under Starlight Conditions written by R. E Miller (III.) and published by . This book was released on 1984 with total page 25 pages. Available in PDF, EPUB and Kindle. Book excerpt: Experimental testing of 10 subjects wearing the AN/PVS-5A (II GEN) night vision goggles (NVG) and ANVIS (III GEN) NVG was conducted under field conditions of ambient starlight illumination (approx. 10-5 mL). The parameters measured were: 1) binocular visual acuity (BVA), 2) stereopsis (depth perception), and 3) a subjective forced choice test. Results showed that BVA was 20/124 and 20/86 for the II and III GEN NVG, respectively. This difference was statistically as well as clinically significant. The stereopsis test results were inconclusive and variable because of the limited sample size and relative inexperience of the subjects in using NVG. Neither BVA nor stereopsis with the NVG was found to be related to standard baseline measures of these parameters in the clinic. Even though the ANVIS has better gain, resolution and sensitivity, 6 out of 10 subjects preferred the AN/PVS-5A for viewing the subjective test. This seemingly paradoxical finding was surmised to be a result of the presence or lack of scene contrast due to the differential sensitivities in the II and III GEN photocathode tubes.
Download or read book Altitude and Night Vision Goggles written by and published by . This book was released on 1998 with total page 0 pages. Available in PDF, EPUB and Kindle. Book excerpt: This paper presents the findings from a study to quantify the effect of mild hypoxia and breathing supplemental oxygen on an aircrew member's static visual acuity while using night vision goggles (NVG). In this within subjects experiment, static NvG visual acuity was measured for 15 subjects at six simulated altitude levels (i.e., ground level, 5,000, 10,000, 15,000, 18,000 and 20,000 feet). Three target contrasts (i.e., high, medium, and low) were used for each visual acuity measurement under both simulated starlight and quarter moon illumination levels. Two supplemental oxygen conditions (i.e., 100% and normal setting) were used at all altitudes and a "no" supplemental oxygen condition was used up to 10,000 feet. Overall, there was a significant decrease in average visual performance across all conditions from the equivalent of 20/44 Snellen acuity at ground level to the equivalent of 20/46 at 20,000 feet. Overall, the "100%" and "normal" oxygen conditions were not significantly different from one another. At the two lowest altitudes, the "no" supplemental oxygen condition did not differ significantly from the other two oxygen conditions. However, at the 10,000 ft. altitude, the "no" supplemental oxygen condition was significantly degraded from both the "100%" and "normal" conditions. Since this study was conducted under an existing generic altitude protocol, the results did not provide complete information on the impact on visual acuity while performing operations at 15,000 feet without supplemental oxygen, applicable to helicopter operations in the mountains. A follow-up study was recommended but not funded.
Download or read book Problemes de Vision Dans Les Operations de Nuit written by and published by . This book was released on 1992 with total page 102 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book The Effects of Aircraft Transparencies on Night Vision Goggle Mediated Visual Acuity written by and published by . This book was released on 1997 with total page 10 pages. Available in PDF, EPUB and Kindle. Book excerpt: Night vision goggles (NVGs) are currently used in a wide variety of military aircraft that were not originally designed for NVGs. Likewise, the windscreens and canopies on these aircraft were not designed with NVGs in mind. Present day windscreens and canopies typically have one or more specialized coatings applied to them. These may be reasonably transparent for visible wavelengths but not so transparent for near infrared light to which the NVGs are sensitive. It was hypothesized that the major mechanism by which aircraft transparencies affect the operation of NVGs is through reduced light levels. This would mean that the key characteristic of interest for determining the effect of an aircraft transparency on the operation of the NVGs would be its transmission coefficient calculated using the spectral sensitivity of the NVGs. This hypothesis was tested by investigating visual acuity performance of trained observers viewing through NVGs for three levels of ambient illumination (1, 2 and 5 times starlight) and three levels of NVG- weighted windscreen transmissivities (58, 76 and 100%). In addition, two levels of contrast were included in the study (20 and 70% modulation contrast). Three trained observers determined the orientation of a Landolt C using a two-alternative, forced-choice step paradigm. A luminance-based model was developed to smoothly combine the effects of illumination level and transmission level for each contrast thus supporting the hypothesis. In addition, the results demonstrate the significant difference between individual observer's performance level and the increased difficulty (higher variability) of performance at lower contrast levels.
Download or read book Night Vision Goggles written by United States. Congress. House. Committee on Armed Services. Subcommittee on Investigations and published by . This book was released on 1989 with total page 128 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book Night Vision Goggle Research and Training Issues for Ground Forces a Literature Review written by Jean L. Dyer and published by . This book was released on 1998 with total page 82 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book Cumulated Index Medicus written by and published by . This book was released on 1995 with total page 1436 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book Measuring Observers Visual Acuity Through Night Vision Goggles written by and published by . This book was released on 1998 with total page 10 pages. Available in PDF, EPUB and Kindle. Book excerpt: Use of night vision goggles (NVGs) for military applications has grown steadily over the past 30 years. Each successive NVG model represents some kind of improvement in terms of size, weight, ruggedness, gain, noise, spectral sensitivity, field-of-view or resolution. The primary focus of this paper is the determination of NVG resolution. Many methods have been devised to measure the resolving power of NVGs and each method has with it an associated variance or accuracy of measurement. This variance is most likely caused by several sources including observer visual capability (since most methods involve visual observations and judgement to assess NVG resolution). The main purpose of this paper is to present the different methods that have been used to assess NVG resolution and to determine to what extent observer visual capability limits the accuracy of NVG resolution measurement. This study uses a methodology that measures an observer's psychometric function when viewing through NVGs (percent correct detection as a function of spatial separation) to determine their visual acuity using probit analysis.
Download or read book Night Vision Goggle Field Expedient Visual Acuity Adjustment Procedures Initial Experiment written by and published by . This book was released on 1996 with total page 46 pages. Available in PDF, EPUB and Kindle. Book excerpt: The third-generation image intensification technology in night vision goggles (NVGs) used by ground forces provides at best 20/40 or 20/45 visual acuity. These acuity levels cannot be achieved unless soldiers adjust their NVGs properly. Documentation available to soldiers does not address optimum adjustment techniques developed by the aviation community nor does it address what can be used in the field to achieve a good setting. We examined the effectiveness and utility of 15 different objects commonly available to soldiers to determine which provided the best visual acuity readings with the AN/PVS-713 NVGs. After training and practice acuity improved by 25% over the baseline assessment. No large differences in readings occurred among the objects. However, a more definitive picture emerged when the average readings were combined with measures of variability and soldier preferences. The initial recommendation is to use one of the following objects for NVG adjustment: trec trunk, vehicle, vehicle trail, stars, blue chem light, or an infrared chem light. Not recommended are bright and/or red light sources, white paper, and trees silhouetted against the night sky. Problems in assessing acuity with NVGs are also discussed.
Download or read book Evaluation of Night Vision Goggle Visual Acuity Degradation While Wearing the FV 9 Laser Eye Protection Spectacle written by and published by . This book was released on 1998 with total page 0 pages. Available in PDF, EPUB and Kindle. Book excerpt: Of all man's senses, vision is recognized as the most critical for aviators to safely fly their aircraft (Tredichi, 1985). Since the introduction of night vision goggles (NVGs), night operations continue to become more demanding as aircrews continue to expand the night operational envelope. As mission variety expands, hazards likewise multiply allowing decreased margins for distraction, error or disorientation without deadly catastrophic consequences. NVGs provide an intensified image of night scenes illuminated by ambient energy in the red and near-infrared portion of the electromagnetic spectrum, which is abundant in the night sky. The intensified imagery is roughly 2,000 to 7,000 times brighter than the original scene, depending upon the type of intensifier tube used, and provides the user with a field of view ranging from 30 - 45 degrees (Kotulak & Rash, 1992). The explosion of NVG users attests to the fact that this technology greatly enhances the ability to conduct night operations. Goggles are used extensively in both rotary and fixed- wing aircraft. Law enforcement, immigration service and military aircrews increasingly rely on night vision devices when darkness restricts normal vision. NVG & work best when the ambient illumination is relatively intense (e.g., full moon) and the contrast of the scene is high. However, scene rendering is significantly degraded when ambient illumination decreases and/or scene contrast decreases (Kotulak & Rash, 1992).
