Analysis of Image Quality using Sobel Filter

Filters can be used to assign new value to a pixel by making use of the local neighbors. This will reduce the noise by smoothing operation by retaining the edges. The method of edge detection is to study the changes in image pixels using the variations of the edge neighboring pixels. In computing changes in these pixel values, selection of the proper window size is essential. In this paper, an attempt is made to implement Sobel filtering technique over Landsat 7 ETM+ satellite data product in order to analyze the impact of bandwidth. The recommendation of window is performed based on the analysis of statistics which best enhances the image while preserving the edges. For satellite image with spatial resolution around 30m, window size 3×3 for SD = 33.527, Mean = 63.265 and SNR = 1.887 is recommended. If results in blurred image, the largest window size 9×9 was recommended to obtain improvement in results.