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Night vision
About: Night vision is a research topic. Over the lifetime, 6004 publications have been published within this topic receiving 67372 citations.
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01 Jul 2002TL;DR: In this article, a night vision system for detecting objects at relatively low visible light levels is presented. But the system is not suitable for the use of cameras and does not have the ability to detect objects in the environment and generate a video signal responsive to the received light.
Abstract: A night vision system 10 is provided for detecting objects at relatively low visible light levels. The system 10 includes an infrared light source 14. The system 10 further includes a thin sheet optical element 16 extending along a first axis 27 receiving light from the infrared light source 14 and reflecting the light generally in a first direction. Finally, the system 10 includes an infrared camera for receiving the light reflected off objects in the environment and generating a video signal responsive to the received light.
71 citations
TL;DR: In this article, a validated questionnaire consisting of 66 items was self-administered by 142 consecutive patients to determine subjective patient satisfaction and self-perceived quality of vision after LASIK to correct myopia and myopic astigmatism.
Abstract: PURPOSE: To determine subjective patient satisfaction and self-perceived quality of vision after laser in situ keratomileusis (LASIK) to correct myopia and myopic astigmatism. SETTING: Department of Ophthalmology, Academic Hospital Maastricht, Maastricht, The Netherlands. METHODS: A validated questionnaire consisting of 66 items was self-administered by 142 consecutive patients. Seven scales covering a specific aspect of quality of vision were formulated. Aspects included global satisfaction, quality of uncorrected and corrected vision, quality of night vision, glare, daytime driving, and night driving. Main outcome measures were responses to individual questions and scale scores, and correlations with clinical parameters including refractive outcome, uncorrected visual acuity, best corrected visual acuity, ablation depth, and scotopic pupil-optical zone disparity were obtained. RESULTS: The mean score for the overall satisfaction was 4.1 +/- 0.71 (SD) (scale 0 to 5.0). A total of 92.2% of patients were satisfied or very satisfied with their surgery, 93.6% considered their main goal of surgery achieved, and 92.3% would choose to have LASIK surgery again. Satisfaction with uncorrected vision was 3.03 +/- 0.71. The mean score for glare was 3.0 +/- 0.9. At night, glare from lights was believed to be more important than before surgery by 47.2%. Glare from oncoming car headlights after surgery was reported by 58.4% and was believed to be more bothersome for night driving than before surgery by 52.8%. Night driving was rated more difficult than before surgery by 39.4%, whereas 59.3% had less difficulty driving at night. There was a significant correlation between the uncorrected vision score and the postoperative spherical equivalent (r = 0.245) and postoperative astigmatism (r = 0.265). There was no correlation between the glare or night vision scores and the degree of correction, the amount of ablation depth, or the disparity between the scotopic pupil and the optical zone. CONCLUSIONS: Self-perceived uncorrected vision after LASIK surgery for the correction of myopia and myopic astigmatism appears to be very good and is related to the postoperative residual error. Although the majority of patients postoperatively experienced glare, particularly with driving at night, this was not related to the pupil-optical zone disparity or degree of correction.
71 citations
TL;DR: This work compares responses of wide-field motion-sensitive neurons in three species of hawkmoth and shows that despite smaller eyes, the motion pathway of D. elpenor is tuned to higher spatial frequencies and lower temporal frequencies than A. atropos, consistent with D.Elpenor's need to detect low velocities for hovering.
Abstract: Nocturnal hawkmoths are known for impressive visually guided behaviours in dim light, such as hovering while feeding from nectar-bearing flowers. This requires tight visual feedback to estimate and counter relative motion. Discrimination of low velocities, as required for stable hovering flight, is fundamentally limited by spatial resolution, yet in the evolution of eyes for nocturnal vision, maintenance of high spatial acuity compromises absolute sensitivity. To investigate these trade-offs, we compared responses of wide-field motion-sensitive neurons in three species of hawkmoth: Manduca sexta (a crepuscular hoverer), Deilephila elpenor (a fully nocturnal hoverer) and Acherontia atropos (a fully nocturnal hawkmoth that does not hover as it feeds uniquely from honey in bees' nests). We show that despite smaller eyes, the motion pathway of D. elpenor is tuned to higher spatial frequencies and lower temporal frequencies than A. atropos, consistent with D. elpenor's need to detect low velocities for hovering. Acherontia atropos, however, presumably evolved low-light sensitivity without sacrificing temporal acuity. Manduca sexta, active at higher light levels, is tuned to the highest spatial frequencies of the three and temporal frequencies comparable with A. atropos. This yields similar tuning to low velocities as in D. elpenor, but with the advantage of shorter neural delays in processing motion.
71 citations
TL;DR: Low-cost hybrid up-conversion devices with infrared sensitivity to 1.5 μm were obtained by integrating a colloidal PbSe nanocrystal near-infrared sensitizing layer on a green phosphorescent organic light emitting diode with maximum photon-to-photon conversion efficiency of 1.3%.
Abstract: Low-cost hybrid up-conversion devices with infrared sensitivity to 1.5 μm were obtained by integrating a colloidal PbSe nanocrystal near-infrared sensitizing layer on a green phosphorescent organic light emitting diode. A ZnO nanocrystal hole blocking layer is incorporated in the devices for keeping the device off in the absence of IR excitation. The maximum photon (1.3 μm)-to-photon (0.52 μm) conversion efficiency is 1.3%. The extension (until 1.5 μm) of the near-infrared wavelengths, which can be converted to visible light, may be able to improve night vision.
70 citations
TL;DR: In this paper, the authors explore the solid-solution series SrAl11.88-xGaxO19:0.12Cr3+ (x = 0, 2, 4, 6, 8, 10, and 12) as phosphors featuring Cr3+-Cr3+) pairs and evaluate structure-property relations within the series.
Abstract: Portable near-infrared (NIR) light sources are in high demand for applications in spectroscopy, night vision, bioimaging, and many others. Typical phosphor designs feature isolated Cr3+ ion centers, and it is challenging to design broadband NIR phosphors based on Cr3+-Cr3+ pairs. Here, we explore the solid-solution series SrAl11.88-xGaxO19:0.12Cr3+ (x = 0, 2, 4, 6, 8, 10, and 12) as phosphors featuring Cr3+-Cr3+ pairs and evaluate structure-property relations within the series. We establish the incorporation of Ga within the magentoplumbite-type structure at five distinct crystallographic sites and evaluate the effect of this incorporation on the Cr3+-Cr3+ ion pair proximity. Electron paramagnetic measurements reveal the presence of both isolated Cr3+ and Cr3+-Cr3+ pairs, resulting in NIR luminescence at approximately 650-1050 nm. Unexpectedly, the origin of broadband NIR luminescence with a peak within the range 740-820 nm is related to the Cr3+-Cr3+ ion pair. We demonstrate the application of the SrAl5.88Ga6O19:0.12Cr3+ phosphor, which possesses an internal quantum efficiency of ∼85%, a radiant flux of ∼95 mW, and zero thermal quenching up to 500 K. This work provides a further understanding of spectral shifts in phosphor solid solutions and in particular the application of the magentoplumbites as promising next-generation NIR phosphor host systems.
70 citations