Pixel-by-pixel reduction of atmospheric haze effects in multispectral digital imagery of water

A study is described in which the effects of the atmosphere on a remotely sensed, multispectral image of water are reduced in a spatially varying manner. The near zero IR reflectance of a water body is used to compute the atmospheric path transmittance and atmospheric path radiance on a pixel-by-pixel basis for a LANDSAT-5 Thematic Mapper image of Lake Ontario. TM Band 4 (0.76-0.90um) image radiance measures are used to define the atmospheric path radiance. Radiosonde data and the LOWTRAN 6 atmospheric model are used to compute the equivalent atmospheric effects for the spectral regions corresponding to the visible wavelength Thematic Mapper image bands on a pixel specific basis. The pixel-by-pixel correction technique is shown to provide a useful reduction of atmospheric effects and to significantly reduce the uncertainty in the image derived measurement of water reflectance