Real-time line extraction using a highly parallel Hough transform board

We describe real-time straight line extraction system and evaluate it. The main part of our system involves a highly parallel processing board on which a highly parallel Hough transform algorithm is mounted. We used the Hough transform, because it useful in line detection. In this board, a content addressable memory (CAM) LSI with dedicated functions for highly parallel image processing is used in this board. Both voting and peak extraction, which make up the Hough transform, are directly executed by the CAM. The CAM acts as a PE (processing element) array that performs highly parallel processing for the Hough transform and it also acts as a memory for two-dimensional Hough space. Sixteen thousand Hough points can be mapped at once and thousands more can be mapped by time-sharing in one CAM. Also variable Hough point resolution is available, because the CAM-based HT algorithm on this board is scalable. Thus line extraction by the Hough transform of 16-K point Hough space for a 256×256 picture can be carried out at video-rates by using a Hough board with a single CAM chip. Moreover a Hough transform with weighted voting for noisy images can also be achieved at video-rates