A Low Cost FPGA Implementation of Retinex Based Low-Light Image Enhancement Algorithm

Real-time low-light image enhancement has several potential applications, such as advanced driver assistance systems (ADAS), remote sensing, object tracking, etc. The Retinex-based algorithms are mostly used to restore the visibility of low-light images. However, they perform complex mathematical operations over a large spatial window. Consequently, their hardware realization is tedious, and few researchers have attempted to address this problem. In this brief, we propose a Retinex-based algorithm that employs a low-cost edge-preserving filter for illumination estimation. Although certain approximations are used to curtail the hardware logic resource requirement, the quality of the enhanced image is not compromised. The proposed architecture requires only 10868 LUTs and 7409 registers when implemented on ZynQ 7 FPGA. Moreover, it can process HD images (1920×1080) at the rate of 60 frames per second (fps).