Approximate Signed Multiplier with Sign-Focused Compressor for Edge Detection Applications
L. Hemanth Krishna, Srinivasu Bodapati, Sreehari Veeramachaneni, BhaskaraRao Jammu, Noor Mahammad Sk
TL;DR
The paper tackles the challenge of energy-efficient signed multiplication for edge-detection tasks by introducing sign-focused compressors, including exact designs A+B+C+1 and A+B+C+D+1, and corresponding approximate variants. It employs a truncation strategy on the lower N−1 partial-product columns coupled with an error-compensation mechanism to balance accuracy and hardware efficiency, implemented within an N×N signed multiplier using a three-region (LSP/CSP/MSP) architecture and a final CSA. The approach achieves a notable $29.21 ext{%}$ reduction in power-delay product and a $14.39 ext{%}$ reduction in power over the best existing multipliers while preserving edge features in a convolution-based edge-detection task, evidenced by a PSNR of $20.13$ dB relative to the exact multiplier. Overall, the work demonstrates practical applicability in real-world image processing pipelines and offers a scalable path to low-power, high-performance edge-detection accelerators.
Abstract
This paper presents an approximate signed multiplier architecture that incorporates a sign-focused compressor, specifically designed for edge detection applications in machine learning and signal processing. The multiplier incorporates two types of sign-focused compressors: A + B + C + 1 and A + B + C + D + 1. Both exact and approximate compressor designs are utilized, with a focus on efficiently handling constant value "1" and negative partial products, which frequently appear in the partial product matrices of signed multipliers. To further enhance efficiency, the lower N - 1 columns of the partial product matrix are truncated, followed by an error compensation mechanism. Experimental results show that the proposed 8-bit approximate multiplier achieves a 29.21% reduction in power delay product (PDP) and a 14.39% reduction in power compared to the best of existing multipliers. The proposed multiplier is integrated into a custom convolution layer and performs edge detection, demonstrating its practical utility in real-world applications.
