Night vision

Abstract: This review provides a survey of various pixel-level image fusion methods according to the adopted transform strategy.The existing fusion performance evaluation methods and the unresolved problems are concluded.The major challenges met in different image fusion applications are analyzed and concluded. Pixel-level image fusion is designed to combine multiple input images into a fused image, which is expected to be more informative for human or machine perception as compared to any of the input images. Due to this advantage, pixel-level image fusion has shown notable achievements in remote sensing, medical imaging, and night vision applications. In this paper, we first provide a comprehensive survey of the state of the art pixel-level image fusion methods. Then, the existing fusion quality measures are summarized. Next, four major applications, i.e., remote sensing, medical diagnosis, surveillance, photography, and challenges in pixel-level image fusion applications are analyzed. At last, this review concludes that although various image fusion methods have been proposed, there still exist several future directions in different image fusion applications. Therefore, the researches in the image fusion field are still expected to significantly grow in the coming years.

Abstract: ABSTRA C T We present the first World Atlas of the zenith artificial night sky brightness at sea level. Based on radiance-calibrated high-resolution DMSP satellite data and on accurate modelling of light propagation in the atmosphere, it provides a nearly global picture of how mankind is proceeding to envelop itself in a luminous fog. Comparing the Atlas with the United States Department of Energy (DOE) population density data base, we determined the fraction of population who are living under a sky of given brightness. About two-thirds of the World population and 99 per cent of the population in the United States (excluding Alaska and Hawaii) and European Union live in areas where the night sky is above the threshold set for polluted status. Assuming average eye functionality, about one-fifth of the World population, more than two-thirds of the United States population and more than one half of the European Union population have already lost naked eye visibility of the Milky Way. Finally, about onetenth of the World population, more than 40 per cent of the United States population and one sixth of the European Union population no longer view the heavens with the eye adapted to night vision, because of the sky brightness.

Abstract: Although compound semiconductors like gallium arsenide have a substantial performance advantage over silicon in photovoltaic and optoelectronic applications, these do not outweigh the costly process of growing large, high-quality layers of these materials and transferring them to flexible or transparent substrates for use in devices such as solar cells, night vision cameras and wireless communication systems. But now John Rogers and his team demonstrate a new fabrication approach that may remove this disadvantage. They grow films of GaAs and AlGaAs in thick, multilayered assemblies in a single deposition sequence, then release the individual layers and distribute them over foreign substrates by printing. The technological potential of this strategy to large-area applications is illustrated with the fabrication of GaAs devices such as field-effect transistors on glass and photovoltaic modules on sheets of plastic. Although compound semiconductors like gallium arsenide (GaAs) offer advantages over silicon for photovoltaic and optoelectronic applications, these do not outweigh the costly process of growing large layers of these materials and transferring them to appropriate substrates. However, a new fabrication approach is now demonstrated: films of GaAs and AlGaAs are grown in thick, multilayered assemblies in a single sequence; the individual layers are then released and distributed over foreign substrates by printing. Compound semiconductors like gallium arsenide (GaAs) provide advantages over silicon for many applications, owing to their direct bandgaps and high electron mobilities. Examples range from efficient photovoltaic devices1,2 to radio-frequency electronics3,4 and most forms of optoelectronics5,6. However, growing large, high quality wafers of these materials, and intimately integrating them on silicon or amorphous substrates (such as glass or plastic) is expensive, which restricts their use. Here we describe materials and fabrication concepts that address many of these challenges, through the use of films of GaAs or AlGaAs grown in thick, multilayer epitaxial assemblies, then separated from each other and distributed on foreign substrates by printing. This method yields large quantities of high quality semiconductor material capable of device integration in large area formats, in a manner that also allows the wafer to be reused for additional growths. We demonstrate some capabilities of this approach with three different applications: GaAs-based metal semiconductor field effect transistors and logic gates on plates of glass, near-infrared imaging devices on wafers of silicon, and photovoltaic modules on sheets of plastic. These results illustrate the implementation of compound semiconductors such as GaAs in applications whose cost structures, formats, area coverages or modes of use are incompatible with conventional growth or integration strategies.

Abstract: NIGHT blindness was recognized as a disease entity in ancient Egypt. Moreover, literature dating from ancient times to the early 20th century contains comments that appear to indicate recognition of the existence of a dietary substance necessary for night vision. In 1913 McCollum and Davis1 reported that an essential lipid-soluble substance in certain foods promoted growth in rats. They later called this substance "Fat Soluble A," to distinguish it from essential water-soluble nutrients ("Water Soluble B"). Further studies by a number of investigators showed that "Fat Soluble A" (later named vitamin A) not only maintained growth but was capable of . . .

Abstract: BackgroundMutations in RPE65 cause Leber’s congenital amaurosis, a progressive retinal degenerative disease that severely impairs sight in children. Gene therapy can result in modest improvements in night vision, but knowledge of its efficacy in humans is limited. MethodsWe performed a phase 1–2 open-label trial involving 12 participants to evaluate the safety and efficacy of gene therapy with a recombinant adeno-associated virus 2/2 (rAAV2/2) vector carrying the RPE65 complementary DNA, and measured visual function over the course of 3 years. Four participants were administered a lower dose of the vector, and 8 were administered a higher dose. In a parallel study in dogs, we investigated the relationship among vector dose, visual function, and electroretinography (ERG) findings. ResultsImprovements in retinal sensitivity were evident, to varying extents, in six participants for up to 3 years, peaking at 6 to 12 months after treatment and then declining. No associated improvement in retinal function was d...