Night vision

About: Night vision is a research topic. Over the lifetime, 6004 publications have been published within this topic receiving 67372 citations.

Development of a headlight glare simulator for a driving simulator

Abstract: We describe the design and construction of a headlight glare simulator to be used with a driving simulator. The system combines a modified programmable off-the-shelf LED display board and a beamsplitter so that the LED lights, representing the headlights of oncoming cars, are superimposed over the driving simulator headlight images. Ideal spatial arrangement of optical components to avoid misalignments of the superimposed images is hard to achieve in practice, and variations inevitably introduce some parallax. Furthermore, driver’s viewing position varies with driver height and seating position preferences, exacerbating misalignment. We reduce the parallax errors using an intuitive calibration procedure (a simple drag-and-drop alignment of nine LED positions with calibration dots on the screen). To simulate the dynamics of headlight brightness changes when two vehicles are approaching, LED intensity control algorithms based on both headlight and LED beam shapes were developed. The simulation errors were estimated and compared favorably with real-world headlight brightness variability.

InGaAs Nanomembrane/Si van der Waals Heterojunction Photodiodes with Broadband and High Photoresponsivity

Abstract: Development of broadband photodetectors is of great importance for applications in high-capacity optical communication, night vision, and biomedical imaging systems. While heterostructured photodetectors can expand light detection range, fabrication of heterostructures via epitaxial growth or wafer bonding still faces significant challenges because of problems such as lattice and thermal mismatches. Here, a transfer printing technique is used for the heterogeneous integration of InGaAs nanomembranes on silicon semiconductors and thus the formation of van der Waals heterojunction photodiodes, which can enhance the spectral response and photoresponsivity of Si photodiodes. Transfer-printed InGaAs nanomembrane/Si heterojunction photodiode exhibits a high rectification ratio (7.73 × 104 at ±3 V) and low leakage current (7.44 × 10–5 A/cm2 at −3 V) in a dark state. In particular, the photodiode shows high photoresponsivities (7.52 and 2.2 A W–1 at a reverse bias of −3 V and zero bias, respectively) in the broad...

Problems With Vision Associated With Limitations or Avoidance of Driving in Older Populations

Abstract: OBJECTIVES: This report examines the role of (a) disease processes affecting vision, (b) reported troubles with vision, (c) physical symptoms affecting the eyes, and (d) objective measures in reported driving limitation due to problems with eyesight among older drivers. METHODS: Data for this study (N = 1,840) were obtained from participants in a community-based study of aging and physical performance in people age 55 or older in the city of Sonoma, California. Each of 16 visual conditions was assessed for impact on reported driving limitation due to eyesight by calculating a "risk" ratio. Then, prevalence of the condition was combined with the ratio to generate an attributable risk for that condition for vision-related limitations in driving. RESULTS: Each condition was significantly associated with reported limitations in driving due to eyesight. "Avoiding physical activity due to vision" (ratio = 3.4) and "trouble seeing steps up/down stairs" (ratio = 2.9) had the strongest association. However, "glasses/contacts required for driving" and "trouble with glare from sun/lights" had the highest attributable risks (35.8 and 29.4). DISCUSSION: The risk ratio is relevant for evaluating individuals; the attributable risk is relevant to planning countermeasures in populations. Addressing specific problems related to vision should substantially reduce driving limitations due to eyesight.

A visual test based on a freeware software for quantifying and displaying night-vision disturbances: study in subjects after alcohol consumption

Abstract: Background In this work, we propose the Halo test, a simple visual test based on a freeware software for quantifying and displaying night-vision disturbances perceived by subjects under different experimental conditions, more precisely studying the influence of the alcohol consumption on visual function.

Effects of sleep deprivation with reference to military operations.

Abstract: This review discusses the need for sleep, effects of sleep deprivation on behaviour and performance in the military, and sleep management recommendations to optimise combat effectiveness. Most people, regardless of sex or race, prefer 7 to 8 hours of sleep each night. Sleeping during the day is less recuperative. Continuous sleep is more effective than multiple short naps-even when the total hours for naps is more. Ten to 20 minute naps are useful when continuous sleep is not possible. Sleep inertia is the 5 to 30 minute period of sluggishness after awakening and important military tasks should be avoided. Previously, continuous work episodes (CWEs) duration was restricted by limited night vision, unreliable equipment and reduced endurance of military personnel. With improved technology, CWEs are now restricted primarily by endurance which is affected by sleep deprivation. This was one of the experiences noted in recent conflicts (e.g. Desert Storm) by personnel in the air force, army and navy. Since there will be changes in operational requirements, several work-rest-sleep plans must be prepared. Sleeping the preferred 7 to 8 hours per 24 hours the week before an operation may help prepare for optimal performance. Personnel should be familiarised with conditions under which they may sleep. During combat, sleep management should ideally avoid situations where all personnel are exhausted at the same time. As sleep debt accumulates, a person's mood, motivation, attention, alertness, short-term memory, ability to complete routines, task performance (errors of omission more than errors of commission) and physical performance will become more negatively affected. Counter measures must then be taken (e.g. time for sleep or naps, changing routines or rotating jobs). Drugs like caffeine and amphetamine can help personnel stay awake. However, they may also keep them awake when they need to sleep- and on awakening, they could suffer from "hang-overs" and are less efficient. Sleep lost need not be replaced hour-for-hour. Therefore, after operations, personnel need continuous sleep for only 10 to 12 hours as longer sleep increases sleep inertia and delays getting back to normal schedules.