Digital Processing of Landsat TM Images for Lineament Occurrence and Spatial Frequency in Sedimentary Rocks

摘要

This report describes and evaluates procedures for the enhancement and extraction of lineament segments by computer processing of digital Landsat Thematic Mapper data. Nearly all results were obtained by convolution of filter windows in the spatial domain. A single procedure was selected as a standard so that results for study areas in South Dakota, Tennessee, Virginia, Wyoming, and small areas of adjacent States could be compared. during the course of the study several new procedures were developed for image enhancement, directional enhancement, and the extraction of edge and line segments from directionally-filtered images; other procedures have previously been described in published literature. The standard procedure proved satisfactory for an extraction of prominent edges and lines in the Landsat images. Part of the problem is caused by the landscape and illumination characteristics of the selected images, but another part is caused by the fact that many boundaries are gradational and do not fit a simple mathematical description of edges and lines. Because of this problem, extracted segments in shale outcrop areas were not compared with those in other types of sedimentary rocks, and measurements of the spatial frequency of occurrence of these segments have a questionable value. A possible solution to the problems found by this study would be: (1) to use a combination of digital elevation data and digital remotely-sensed data of the same area; and (2) to combine directional enhancement and lineament segment extraction with visual detection, screening, and editing. This approach would exploit the main advantages and minimize the disadvantages of both visual and digital analysis. (ERA citation 11:032880)