Approximate subtractors designed for image processing applications

Approximate circuits play a vital role in enhancing efficiency and optimizing resource use in modern computing systems. Their benefits are particularly notable in fields that tolerate minor inaccuracies, such as image processing, signal processing, and data mining, where a slight reduction in precision can lead to substantial savings in power and space requirements. This study explores an innovative design for an approximate full subtractor based on the principle of pruning, meticulously implemented using universal two-input NOR gates, valued for their cost efficiency, low power consumption, and compact design. Existing approximate subtractors have been designed using non-universal basic gates such as XOR, XNOR, NOT, and AND gates. In contrast, the proposed approach utilizes only the universal NOR gate, leading to improved circuit efficiency in terms of area, delay, and power consumption. Additionally, this work evaluates performance metrics of approximate circuits, demonstrating their effectiveness in various image processing applications involving full subtractors.