Hough transform line reconstruction on FPGA using back-projection
Donald G. Bailey · 2017
While there have been several implementations of the Hough transform on FPGA, one common problem is how to efficiently reconstruct the lines onto an output video stream. This paper uses a simplified Canny filter for preprocessing, then performs a parallel Hough transform, with a small dedicated processor associated with each angle bin. Logic is optimised using incremental addressing associated with the streamed input. Peaks are detected during vertical blanking, while clearing the Hough transform accumulators. Detected peaks are marked in the parameter memory, enabling the lines to be directly reconstructed by back projection while transforming the next frame. This novel back-projection technique enables any number of lines to be reconstructed directly from their parameters with no additional logic, and only one additional memory bit per Hough transform bin.