Landsat ETM+7 Digital Image Processing Techniques for Lithological and Structural Lineament Enhancement: Case Study Around Abidiya Area, Sudan

ABSTRACT

Remote sensing techniques were applied to delineate lithological and structural features of the area around Abidiya area in north central Sudan. Landsat Enhanced Thematic Mapper Plus (ETM + 7) Satellite data of five multispectral bands (1, 2, 3, 4, 5, & 7) were utilized in the course of digital image processing techniques. The techniques consist of spectral enhancement (e.g. linear contrast stretching and image ratio) and spatial enhancement such as image filtering and Intensity-Hue-Saturation transformation (IHS). The spectral enhancement techniques were used to extract the initial geological information, which showed a clear discrimination of felsic and granitic rocks from mafic and ultramafic lithologies of ophiolitic origin. Intensity, Hue, Saturation (HIS) transformation proved to be superior in enhancing geological information extraction. The high pass and directional filtering techniques allows the delineation of the lineaments in the region.The patterns recognized in the digitally processed satellite images assist in extract the initial lithological information as well as delineate the regional structural lineaments in the region. Further these patterns used as a base for generated geological and structural maps through visual interpretation and ground truthing.

Keywords: