Investigation of the algorithm for detecting image brightness on the basis of the Wilcokson criterion

The article is devoted to the topic of image processing based on the application of the nonparametric Wilcoxon criterion. The application of this criterion involves converting the brightness of the image into such an attribute as the value of the rank function for each pixel of the analyzed area of the image, while calculating the extremum of the rank function makes it possible to establish the location and type of changes in brightness in the image. However, as previous studies have shown, the value of the extremum value depends on the signal-to-noise ratio in the image, and along with the true extrema, local extrema are also distinguished, which complicates the solution of the problem of further image segmentation. This paper presents the results of statistical studies of the Wilcoxon test for detecting brightness differences in images with different signal-to-noise ratios and sample sizes. The minimum signal-to-noise ratio is established, at which the extremum of the rank function tends to its maximum or minimum value, and on the basis of a statistical analysis of the behavior of the rank function, it is proposed to use the difference of rank functions to exclude the allocation of local extrema.