Realization of a high-efficient GDI-based 4:2 compressor for sum of absolute difference detection in image and signal processing

Abstract

A new 4:2 approximate compressor is designed based on gate diffusion input (GDI), which has 14 transistors and only 6 errors in its outputs. The integration of the GDI with the dynamic threshold (DT) overcomes the body effect by the selection of carbon nanotube field-effect transistors (CNTFET) technology. By embedding the proposed compressor in the 8-bit sum of absolute difference (SAD) system, an area of 284.6 µm2 is occupied and a reliable system for difference detection between two images and electrocardiogram (ECG) results. Considering the fair conditions of comparison, the proposed circuit has significant performance in terms of circuitry parameters such as power, delay, and figure of merits (FoMs). In terms of power-delay-product (PDP) and power-delay-area-product (PDAP) the proposed cell shows a saving of 27 % and 47 %, respectively. A 40 % improvement in terms of a FoM containing PDP and power signal-to-noise ratio (PSNR) compared to the closest competitor qualifies the proposed circuit over the other counterparts. The proposed cell has a high performance under the difference detection in images and ECGs.