Computer Processing of LANDSAT Data for Geologic Applications: ABSTRACT

Abstract

The main objectives of computer processing of LANDSAT data for geologic applications are to improve display of image data to the analyst or to facilitate evaluation of the multispectral characteristics of the data. Image enhancements involved adjustments of brightness values for individual picture elements. Image classification involves determination of the brightness values of picture elements for a particular cover type. Histograms are used to display the range and frequency of occurrence of brightness values. LANDSAT 1 and 2 data are preprocessed at Goddard End_Page 537------------------------------ Space Flight Center (GSFC) to adjust for the detector response of the Multispectral Scanner (MSS). Because illumination conditions and landscape characteristics vary considerably and detector response changes with time, the radiometric adjustments applied at GSFC are seldom perfect and detector striping remains in LANDSAT data. Therefore, adjustments are applied to minimize the effects of striping, and to adjust for bad data lines, line segments, and lost individual pixel data. Rotation of the earth under the satellite and movements of the satellite platform introduce geometric distortions in the data which must be compensated for if image data are to be correctly displayed to the data analyst. Adjustments to LANDSAT data are made to compensate for variable solar illumination and for tmospheric effects. Geometric registration of LANDSAT data involves determination of the spatial location of a pixel in the output image and determination of the new value of the pixel in the output image. End_of_Article - Last_Page 538------------