Read Books Online and Download eBooks, EPub, PDF, Mobi, Kindle, Text Full Free.
Reproducibility Of Night Vision Goggle Visual Acuity Measurements Using Landolt Cs
Download Reproducibility Of Night Vision Goggle Visual Acuity Measurements Using Landolt Cs full books in PDF, epub, and Kindle. Read online Reproducibility Of Night Vision Goggle Visual Acuity Measurements Using Landolt Cs ebook anywhere anytime directly on your device. Fast Download speed and no annoying ads. We cannot guarantee that every ebooks is available!
Book Synopsis Reproducibility of Night Vision Goggle Visual Acuity Measurements Using Landolt C's by :
Download or read book Reproducibility of Night Vision Goggle Visual Acuity Measurements Using Landolt C's written by and published by . This book was released on 1999 with total page 7 pages. Available in PDF, EPUB and Kindle. Book excerpt: The main purpose of the study was to determine reproducibility limits of night vision goggle (NVG) acuity measurement under relatively high and low illumination levels. Psychometric acuity functions of three observers were repeatedly measured using Landolt C's as stimuli. The reproducibility limits of the Snellen acuity value (20/xx) relating to 50, 75 and 95% correct (adjusted for chance) were then determined. Reproducibility limit is defined as approximately 95% of all pairs of replications (20/xx) from the same illuminance and same observer, generated on different days, should differ in absolute value by less than the reproducibility limit. It was determined that for the lower illumination (8.61E-4 lux) at 50% corrected for chance probability level, the reproducibility limit was 5.1 Snellen acuity (20/xx) and for the higher illumination (1.38E-2 lux), 2.5 Snellen acuity. These limits were 17% and 13% of mean acuity, respectively.
Book Synopsis Reproducibility of Nigh Vision Goggle Visual Acuity Measurements Using Landolt C's by :
Download or read book Reproducibility of Nigh Vision Goggle Visual Acuity Measurements Using Landolt C's written by and published by . This book was released on 1999 with total page 7 pages. Available in PDF, EPUB and Kindle. Book excerpt: The main purpose of the study was to determine reproducibility limits of night vision goggle (NVG) acuity measurement under relatively high and low illumination levels. Psychometric acuity functions of three observers were repeatedly measured using Landolt C's as stimuli. The reproducibility limits of the Snellen acuity value (20/xx) relating to 50, 75 and 95% correct (adjusted for chance) were then determined. Reproducibility limit is defined as approximately 95% of all pairs of replications (20/xx) from the same illuminance and same observer, generated on different days, should differ in absolute value by less than the reproducibility limit. It was determined that for the lower illumination (8.61E-4 lux) at 50% corrected for chance probability level, the reproducibility limit was 5.1 Snellen acuity (20/xx) and for the higher illumination (1.38E- 2 lux), 2.5 Snellen acuity. These limits were 17% and 13% of mean acuity, respectively.
Book Synopsis Night Vision Goggle Field-expedient Visual Acuity Adjustment Procedures by :
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:
Book Synopsis Measuring Observers' Visual Acuity Through Night Vision Goggles by :
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.
Author :National Aeronautics and Space Administration (NASA) Publisher :Createspace Independent Publishing Platform ISBN 13 :9781722214555 Total Pages :42 pages Book Rating :4.2/5 (145 download)
Book Synopsis Evaluation of Visual Acuity with Gen 3 Night Vision Goggles by : National Aeronautics and Space Administration (NASA)
Download or read book Evaluation of Visual Acuity with Gen 3 Night Vision Goggles written by National Aeronautics and Space Administration (NASA) and published by Createspace Independent Publishing Platform. This book was released on 2018-07-02 with total page 42 pages. Available in PDF, EPUB and Kindle. Book excerpt: Using laboratory simulations, visual performance was measured at luminance and night vision imaging system (NVIS) radiance levels typically encountered in the natural nocturnal environment. Comparisons were made between visual performance with unaided vision and that observed with subjects using image intensification. An Amplified Night Vision Imaging System (ANVIS6) binocular image intensifier was used. Light levels available in the experiments (using video display technology and filters) were matched to those of reflecting objects illuminated by representative night-sky conditions (e.g., full moon, starlight). Results show that as expected, the precipitous decline in foveal acuity experienced with decreasing mesopic luminance levels is effectively shifted to much lower light levels by use of an image intensification system. The benefits of intensification are most pronounced foveally, but still observable at 20 deg eccentricity. Binocularity provides a small improvement in visual acuity under both intensified and unintensified conditions. Bradley, Arthur and Kaiser, Mary K. Ames Research Center ...
Book Synopsis Night Vision Goggle Field-Expedient Visual Acuity Adjustment Procedures: Initial Experiment by :
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.
Book Synopsis Evaluation of Visual Acuity with Gen 3 Night Vision Goggles by :
Download or read book Evaluation of Visual Acuity with Gen 3 Night Vision Goggles written by and published by . This book was released on 1994 with total page 46 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Book Synopsis Evaluation of Visual Acuity with Gen III Night Vision Goggles by : Arthur Bradley
Download or read book Evaluation of Visual Acuity with Gen III Night Vision Goggles written by Arthur Bradley and published by . This book was released on 1994 with total page 44 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Book Synopsis The Effect of Signal-to-Noise Ratio on Visual Acuity Through Night Vision Goggles by : Joseph T. Riegler
Download or read book The Effect of Signal-to-Noise Ratio on Visual Acuity Through Night Vision Goggles written by Joseph T. Riegler and published by . This book was released on 1991 with total page 30 pages. Available in PDF, EPUB and Kindle. Book excerpt: Since 1971, night vision goggles (NVGs) have been used by the military to enable personnel to perform visual operations in a nighttime environment. The key component of these devices is the image intensifier tube. Currently, no studies were identified which relate the signal-to-noise ratio (SNR) of image intensifiers to human visual acuity. The purpose of the present research was to determine the effect of NVG intensifier tube SNR on visual acuity. Visual acuity, using PVS-7 third generation NVGs, was measured for twelve participants at quarter moon and starlight illumination levels for four intensifier tubes with different SNRs. The range of SNR examined was 11.37 to 17.92. Visual acuity was assessed using Landolt C charts with target contrasts of 20 to 95 percent. The distance at which the acuity targets were resolved was recorded for each of the four illumination and contrast conditions. The results showed that increases in image intensifier tube SNR, illumination level, and contrast affected visual acuity. Regression analyses were performed to obtain estimated equations relating SNR to visual acuity for each experimental condition. The results were used to develop predictive guideline tables to provide approximate percent degradation/ improvement in visual acuity based upon intensifier tube signal-to-noise ratio ... Visual acuity, Night vision goggles, Signal-to-noise ratio, Image intensifier tubes.
Book Synopsis Night Vision Goggle Field-expedient Visual Acuity Adjustment Procedures by :
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 22 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Book Synopsis Comparative Night Vision Goggle Visual Acuity Measurements Performed in the A-10 Aircraft in an Operational Setting by :
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.
Book Synopsis Night Vision Goggle Research and Training Issues for Ground Forces, a Literature Review by : Jean L. Dyer
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:
Book Synopsis Image Contrast and Visual Acuity Through Night Vision Goggles by : Jeff C. Rabin
Download or read book Image Contrast and Visual Acuity Through Night Vision Goggles written by Jeff C. Rabin and published by . This book was released on 1996 with total page 0 pages. Available in PDF, EPUB and Kindle. Book excerpt: The purpose of this study was to investigate effects of display contrast and luminance on visual resolution through NVGs. Computer-generated letter charts were used to measure visual acuity across the range of luminances and contrasts one can encounter when viewing an NVG display. The results indicate that display luminance cannot, in itself, account for the level of acuity achieved through NVGs. Understanding the contrast and luminance transfer of NVGs is important for predicting human visual performance, and for developing improved night vision devices.
Book Synopsis Night Vision: Current Research and Future Directions, Symposium Proceedings by : Working Group on Night Vision
Download or read book Night Vision: Current Research and Future Directions, Symposium Proceedings written by Working Group on Night Vision and published by National Academies Press. This book was released on 1987-01-01 with total page 351 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Book Synopsis Effect of Incompatible Light on Modified Class B Night Vision Goggle-Aided Visual Acuity and Contrast Sensitivity by :
Download or read book Effect of Incompatible Light on Modified Class B Night Vision Goggle-Aided Visual Acuity and Contrast Sensitivity written by and published by . This book was released on 1997 with total page 0 pages. Available in PDF, EPUB and Kindle. Book excerpt: MIL-L-85762A, Lighting, Aircraft, Interior, Night Vision Imaging System (NVIS) Compatible, defines criteria for assessing night vision goggle (NVG) compatibility of cockpit lighting. As part of the assessment procedures, NVG aided visual acuity (VA) is measured using the USAF Tri-Bar Chart. A cockpit light is incompatible if NVG aided VA is degraded. An alternative method of measuring NVG aided VA uses an NVG Chart. This research assessed whether the two NVG aided VA assessment techniques reveal the same levels of degradation in NVG aided VA. NVG aided contrast sensitivity (CS) also was measured to determine its usefulness in assessing the compatibility of a cockpit light. Three NVG CS charts were developed having spatial frequencies of 3, 6, and 12 cycles per degree (cpd). NVG performance was degraded by incompatible light, and the amount of degradation was assessed using the two VA and CS measures. Measurements were made using a modified Class B NVG. Another objective of this research was to assess the compatibility of the modified Class B NVG with compatible cockpit light defined in MIL-L-85762A. The results revealed that NVG aided VA did not differ between the two VA charts. For the green light, NVG aided CS was degraded only for the high spatial frequency (12 cpd). However, for the red light, NVG aided CS was degraded for all three spatial frequencies. NVG aided CS was sensitive to the presence of incompatible light. The modified Class B NVG is compatible with the lighting requirements defined in MIL-L-85762A.
Book Synopsis Night Vision Goggle Assessment Techniques with Incompatible Cockpit Lighting and a Modified Class B Goggle by : Randall William Gibb
Download or read book Night Vision Goggle Assessment Techniques with Incompatible Cockpit Lighting and a Modified Class B Goggle written by Randall William Gibb and published by . This book was released on 1996 with total page 158 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Book Synopsis Effect of Incompatible Light on Modified Class B Night Vision Goggle-aided Visual Acuity and Contrast Sensitivity by : Randall W. Gibb
Download or read book Effect of Incompatible Light on Modified Class B Night Vision Goggle-aided Visual Acuity and Contrast Sensitivity written by Randall W. Gibb and published by . This book was released on 1997 with total page 22 pages. Available in PDF, EPUB and Kindle. Book excerpt: MIL-L-85762A, Lighting, Aircraft, Interior, Night Vision Imaging System (NVIS) Compatible, defines criteria for assessing night vision goggle (NVG) compatibility of cockpit lighting. As part of the assessment procedures, NVG aided visual acuity (VA) is measured using the USAF Tri-Bar Chart. A cockpit light is incompatible if NVG aided VA is degraded. An alternative method of measuring NVG aided VA uses an NVG Chart. This research assessed whether the two NVG aided VA assessment techniques reveal the same levels of degradation in NVG aided VA. NVG aided contrast sensitivity (CS) also was measured to determine its usefulness in assessing the compatibility of a cockpit light. Three NVG CS charts were developed having spatial frequencies of 3, 6, and 12 cycles per degree (cpd). NVG performance was degraded by incompatible light, and the amount of degradation was assessed using the two VA and CS measures. Measurements were made using a modified Class B NVG. Another objective of this research was to assess the compatibility of the modified Class B NVG with compatible cockpit light defined in MIL-L-85762A. The results revealed that NVG aided VA did not differ between the two VA charts. For the green light, NVG aided CS was degraded only for the high spatial frequency (12 cpd). However, for the red light, NVG aided CS was degraded for all three spatial frequencies. NVG aided CS was sensitive to the presence of incompatible light. The modified Class B NVG is compatible with the lighting requirements defined in MIL-L-85762A.
