The role of the correlation coefficient on the statistical behavior of a simple band ratio

摘要

The subject of the present paper is how are the statistical parameters of an image of a simple band ratio are influenced, in quantitative terms, by the correlation coefficient between the two bands. The possibility to modify the expression for the ratio of highly correlated bands, in order to enhance the tonality contrast between the target of interest and the adjacent pixels, is also studied. Using proper bivariate Gaussian distributions it is shown that the standard deviation and the entropy of the image decrease considerably, as well as the correlation coefficient increases. When the correlation coefficient is high, it is possible to use the square of the simple ratio, in order to improve the contrast of the image. The results and conclusions of this paper may be useful in mapping the vegetation cover or detecting lithological units and mineralization zones with the aid of remote sensing technology.