期刊名称：Archiwum Fotogrametrii, Kartografii i Teledetekcji
印刷版ISSN：2083-2214
出版年度：2010
卷号：21
语种：English
出版社：Main Board of Association of Polish Surveyors
摘要：The phenomenon of bidirectional spectral reflectance (BRDF) is concerned with analysis of spectral reflectance as dependent on the direction of illumination and observation of a facility located on the surface of the Earth. Most aerial cameras are equipped with conical view lenses. One consequence is variation of observation angle in the plane of an aerial photograph. Aerial photographs,performed mostly in strips constituting a block,are characterized by a large overlap. Some photographed objects can be registered on up to 6 photos. The same object in every picture has different brightness in different spectral channels. In practice,this makes it difficult to offset the brightness / color between adjacent images,and for large areas – problems with classifying same objects to a single class. In this work 6 photographs were analyzed for brightness change. Due to changes in camera position for designated sites the brightness changed in four spectral channels from 3DN (0.07% of 12-bit radiometric resolution) to 1162DN (28%). The average change of brightness was 128 DN (3%). For the whole block of aerial photographs (131 pictures) that are available to the author,and are not directly used in this study,an average of 95% of all pixels are in the range of 1200 units of DN. In this context,the average brightness changes due to changes in camera position on subsequent images are already the average of 10% instead of 3%.
其他摘要：Zjawisko dwukierunkowego odbicia spektralnego (BRDF) dotyczy analizy wielkości odbicia spektralnego w zależności od kierunku oświetlenia i obserwacji obiektu położonego na powierzchni Ziemi. Większość kamer lotniczych wyposażona jest w obiektywy o stożkow
