A study of the performance of a new sharpening filter

摘要

In the present paper is studied the effect of a recently proposed filter on satellite images. In spatial frequency domain, the response of the filter is controlled by the parameters b and k, which are positive real numbers. 5 x 5 convolution masks at the image are constructed, which simulate the response of the filter at frequency domain, for various b and k values. In order to study the performance of the filter in qualitative and quantitative terms, these masks were applied on various satellite images, which were taken over urban centers, as well as broader regions with different land cover types and geomorphological features. For each filtered image, there were computed the standard deviation and the signal to noise ratio.The statistical analysis showed that for k between 0.5 and 0.7 and for b between 0.8 and 1.2, one can produce images with considerably enhanced tonalities between adjacent pixels. Experimentation with satellite images showed that convolution masks with these k and b parameters produce images where lineaments such as coastal lines, drainage or road network can be clearly seen. The potential user is encouraged to try on various k and b values, in order to obtain the optimum result for the area under study.