FPGA implementation of a real-time biologically inspired image enhancement algorithm

This paper presents an FPGA implementation of a novel image enhancement algorithm, which compensates for the under-/over-exposed image regions, caused by the limited dynamic range of contemporary standard dynamic range image sensors. The algorithm, which is motivated by the attributes of the shunting center-surround cells of the human visual system, is implemented in Altera Stratix II GX: EP2SGX130GF1508C5 FPGA device. The proposed implementation, which is synthesized in an FPGA technology, employs reconfigurable pipeline, structured memory management, and data reuse in spatial operations, to render in real-time the huge amount of input data that the video signal comprises. It also avoids the use of computationally intensive operations, achieving the required specifications in terms of flexibility, timing, performance and visual quality. The proposed implementation allows real-time processing of color images with sizes up to 2.5 Mpixels, at frame rate of 25 fps. As a result, the architectural solution described in this work offers a low-cost implementation for automatic exposure correction in real-time video systems.