Hierarchical Hough transform based on pyramidal architecture

A hierarchical Hough transform (HT) based on pyramidal architecture is described, being a main component of the low-to-medium spatial vision subsystem for a mobile robot. The sequence of processing in the system originally conceived to be essential to the extraction of line features in indoor scenes consisted of: histogram equalization, smoothing with the use of a medial filter, edge detection using the Sobel edge detectors, binarization to extract the edges detected, labeling, rebinarization and thinning to refine the edges to thin lines, and line extraction using a hierarchical approach to the HT method. The task was to establish the importance of each step for the success of the hierarchical HT. It was implemented on a 386-based personal computer with 640 K memory and proved to give results of high quality as compared with the standard HT implementation.<>