VLSI Design and Implementation of Real-Time Adaptive Video Enhancement for Low Bit Rate Applications

摘要

In this paper, VLSI implementation of a Discrete Wavelet Transform based contrast and edge enhancement algorithm is proposed. Separate edge and contrast enhancement can be achieved using discrete wavelet transform and the computation cost in the wavelet domain is less than that in the spatial domain, our proposed algorithm uses fixed gain high boost filter on detail wavelet coefficients for edge enhancement and adaptive gain high boost filter on approximation coefficients for contrast enhancement. The adaptive gain is computed from the local mean value and processing the wavelet coefficients locally has increased the chances of success under different environmental conditions. The data storage requirements, for forward and backward wavelet transform and for applying high boost filters on approximation and detail wavelet coefficients, are minimized by using pixels processing instead of frame processing. We have used FPGA Block RAMs for storing processing and processed data and computed wavelet coefficients. Our proposed VLSI architecture is designed for real-time video enhancement. The experiments show that utilizing the proposed algorithm can achieve robust edge and contrast enhancement on frames recorded under different environmental conditions.