FPGA-Based Robust Ellipse Estimation for Circular Road Sign Detection

Estimating parametric curves from images using robust fitting algorithms is a well-known and important computer vision task. We present a complete FPGA design and im- plementation of a fast and robust model fitting algorithm for real-time ellipse detection on video streams. The pro- posed solution relies on a the RANSAC algorithm, modi- fied for FPGA deployment, in combination with an image- preprocessing pipeline in order to perform the intensive pixel-level analysis, reducing each frame to a simple bi- nary image of edges. The design has been developed in a parallel fashion and with specific architectural solutions so as to allow a fast response without degrading the func- tional performances. Experimental results on synthetic and real data show that our implementation, synthesized onto a Xilinx Spartan-3A DSP 3400A device, succesfully runs in real-time with a low resource occupation, while maintain- ing a functionality comparable with the floating-point soft- ware version.