Computer perception of repetitive textures
Leonard George Chadborn Hamey · 1988
This dissertation presents research in computer analysis of two dimensional regular repetitive textures in real-world images. Previous efforts in this field have assumed simple grid-like repetitive structure. In contrast, we assume only locally simple repetitive structure. This local model of repetition leads to an algorithm that is able to analyse severely distorted repetitive textures, which occur in real-world scenes. We demonstrate the success of this algorithm on a variety of images. An essential part of describing repetitive textures is extracting the frequency of repetition. However, regular repetitions admit many alternate frequency descriptions. We define the fundamental frequencies of a repetition as the two shortest independent vectors between elements of the repetition. We show that the fundamental frequency vectors are the most perpendicular basis vectors for the repetition and that they correspond to the relative neighbourhood graph of the repetitive pattern. Our algorithm exploits these properties to extract the fundamental frequencies of repetitive textures. It is difficult to extract repetition frequency when the element of repetition is also