Design of a Hardware-Efficient Approximate 4-2 Compressor for Multiplications in Image Processing

This letter presents a novel hardware-efficient approximate 4-2 compressor design that significantly enhances accuracy through a systematic analysis of input patterns obtained from practical applications. We incorporate a majority operation and a compound gate in the compressor design to effectively boost hardware efficiency in multiplications. Our design approach results in substantial error reductions, with normalized mean error distance (NMED) and mean relative error distance (MRED) decreasing by up to 74.84% and 82.04%, respectively, compared to existing approximate multipliers discussed in this letter. When implemented in a 32-nm CMOS technology, the approximate multiplier adopting the proposed 4-2 compressor achieves excellent hardware efficiency, reducing area, power, and energy consumption by up to 8.95%, 13.02%, and 13.02%, respectively, compared to the other alternatives. Moreover, our design delivers enhanced performance in image processing tasks, achieving up to a $4.84\times $ increase in peak signal-to-noise ratio (PSNR) compared to other designs, all while optimizing hardware efficiency.