Direct filtering and enhancement of biomedical images based on morphological spectra

Abstract

In the paper a method of filtering of biomedical images aimed at their enhancement for direct visual examination or for automatic segmentation of regions covered by typical textures is presented. For this purpose morphological spectra (being a modification of the systems of orthogonal 2D Walsh functions) are used. Filtering consists in assigning relative weights coefficients to spectral components representing typical morphological micro-structures. However, direct filtering makes possible elimination of calculation of the components of morphological spectra, because filtered values of image elements are given as linear combinations of the values of the original image in fixed basic windows. The method of calculation of the transformation coefficients in details is described. Application of the method is illustrated by an example of cerebral SPECT image examination.