The Investigations of Gypsum Rocks Outcrops in Sheikh-Ibrahim Anticline by Ratio Images

To display the significance of the remotely sensed data in geological exploration, ratio images were used to allocate the prospected area of gypsum rocks. Ratioing operation removes the albedo information and enhances the reflectivity of the cover type .A combination of ratio images based on the spectral characteristics of gypsum rocks was selected. This combination consists of (Band4/Ban3), (Band7/Ban1) and (Band7/Ban4). Gypsum rocks are expected to appears in white tone in ratio images (Band4/Ban3), while it expected to appears in dark tone in the ratio images (Band7/Ban1) and (Band7/Ban4) . However, to exploit the capability of ratio images for better discrimination, these ratio images were combined into a false colors composites which reflect the gypsum rocks in blue color in ratio images ((Band 4 / Band 3)G, (Band 7 / Band 1)B and (Band 7 /
Band 4)R)). To avoid the false ratio value which appears as result of scattering effective images portrayed in short wavelength, the raw images were subjected to methods of image correction. Finally, all the operations of correction and ratioing were programmed in C++ language. The software is adaptive so that it can be used for any cover type discriminating using any sensor type.