Real-time Linear Projection Speed Sign Detection System in Low Light Conditions

In this paper, a real-time algorithm for detecting speed signs in low light conditions is presented. This application oriented algorithm starts with performing the popular difference of Gaussian (DoG) filter as a pre-processing step. After that pixels are thresholded and classified into predefined classes. The paper introduce an efficient voting method called linear projection, in which each pixel that belongs to any predefined classes continuously votes on an incremental image along its gradient vector to identify centre of the speed sign candidates. This algorithm is fast, reliable, suitable for real-time hardware (FPGA) implementation. A Matlab simulation model is built to verify the algorithm´s operation in nighttime driving conditions. A FPGA initial prototype of this algorithm has been implemented and showed promising results.