منابع مشابه
Singular Value Decomposition of Images from Scanned Photographic Plates
Abstract. We want to approximate the n m× image A from scanned astronomical photographic plates (from the Sofia Sky Archive Data Center) by using far fewer entries than in the original matrix. By using rank of a matrix, k we remove the redundant information or noise and use as Wiener filter, when rank m k < or n k < . With this approximation more than 98% compression ration of image of astronom...
متن کاملStudy of USNO photographic plates of the Galilean satellites
About 500 photographic plates of the Galilean satellites made with the 26-inch refractor of USNO in Washington DC from 1967 to 1998 were digitized and reduced using the UCAC2 star catalog. Results on the ephemerides of the Galilean satellites and on the determination of the mass of Amalthea will be presented. An evaluation of the accuracy of several ephemerides of Jupiter on the 1967-1998 perio...
متن کاملAperture Photometry of Saturated Star Images from Digitised Photographic Plates
Saturated stellar images on digitised photographic plates are many times greater in area than the ‘seeing disk’ seen in unsaturated CCD images. Indeed the flux profile of a bright star can be traced out for several degrees from the star’s centre. The radius of the saturated stellar image can often be directly related to the magnitude of the star, a fact well known and exploited in iris photomet...
متن کاملDigital reconstruction of fragmented photographic glass plates: the case of archaeological photography
A recent digitalization project of the textual and iconographical fund of Department of Archaeology Library of the Catania University, one of the largest and oldest among Italian academies, presented the challenging problem of the iconographical resources on glass plates coated by silver halide. The Library has an archive of about 3,000 glass plates. Several of these are damaged and fractured. ...
متن کاملOn the Distribution of AgBr Grains in Photographic Plates for Ion Detection in Mass-Spectrometers
Investigations have been carried out on the distribution of AgBr-grains in unexposed photographic plates (type Q2, 11 f o r d Ltd.) used for ion detection in mass-spectrometers. Electron micrographs show that a large fraction of the grains protrude about halfway out of the gelatine matrix and that these grains are covered by a very thin gelatine layer on the side facing the ions. The mean proje...
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ژورنال
عنوان ژورنال: Nature
سال: 1892
ISSN: 0028-0836,1476-4687
DOI: 10.1038/047011b0