Extraction of texture elements from images of shaded scenes

摘要

A method is proposed that can extract texture elements in spite of the presence of global shading variations. It is assumed that a texel contains at least one brightness maximum and that the boundary of the texel is a closed contour with constant brightness below the maximum. The method decomposes a grayscale image into a stack of binary images by thresholding the grayscale image with a set of appropriately chosen thresholds. As a result, the binary image stack contains many connected regions, among which the most appropriate ones are selected as final texels. This selection process examines the binary image stack from top to bottom and decides on the basis of a few rules which of the regions become final. Experimental results for both synthesized and real images of natural scenes are reported, demonstrating the suitability of the extracted texels for computing orientation fields and for segmenting multiple textures.