A Modified Texture Filtering Technique for Satellite Images

The present study was undertaken to develop a modified texture analysis algorithm based on the properties of texture spectrum (TS) domain for the satellite images. In texture analysis some specific spatial filters are required, which can transform the image based on the textural features instead of changing the spectral properties; the image is thus characterized by its texture spectrum. This papers deals with extraction of micro texture unit of 3X3 as well as 5X5 window to represent the local texture unit information of a given pixel and its neighbourhood. In this technique, the texture unit comprising of eight neighbourhood elements is decomposed into two separable texture units, namely, cross texture unit and diagonal texture unit of four elements each. These four elements of each texture unit occur along the cross direction and diagonal direction. For each pixel, crossdiagonal texture matrix (CDTM) has been evaluated using several types of combinations of cross and diagonal texture units. This approach drastically reduces the computational time. The occurrence frequency of each CDTM value obtained in the entire image is recorded. Two different approaches, namely, mean and median, have been subsequently carried out while processing the data. It is observed that the median technique with 3X3 window shows best result in the reduction of noise in satellite data.