Abstract
This paper describes how band ratioing is useful in providing unique information not available in any single band that is useful for discriminating ground features. It also presents the significance of spatial filtering and rescaling in an image. In this study, four different band ratios were created which helped in extracting useful information regarding the ground features. The colour composite image of the three indices revealed some important information about the ground features and eliminated the effects of shadowing. The ratio with low correlation between the bands, i.e. ratio of red versus nir, was found to contain greater information than the ratios with high correlation between the bands. The NDVI ratio was rescaled by using both the standard scaling algorithm and raster calculator algorithm. A scatter plot was plotted to verify the results were same for both the rescaled NDVI channels. The panchromatic layer containing just band 4 was extracted and median low-pass filter and Sobel edge detector high-pass filter were applied to it. The median filter was found to smooth the image, remove noise and maintain the edges. The Sobel edge filter was found to enhance sharp edges.
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