Image Blending using Approximate Multiplication

Image blending, which involves a mix of images, is used in computer graphics and photo editing. For example, two images can be blended through addition or multiplication. Usually, accurate addition or multiplication is performed to blend the images. In this paper, we discuss image blending using approximate multiplication. We show that approximate multiplication can yield visually similar blended images as accurate multiplication through an example illustration. We discuss a systematic approximation of the accurate array multiplier by introducing a series of vertical cuts in it and assign different combinations of binary values to the dangling internal inputs and dangling product bits. For an 8x8 image blending operation, our proposed approximate array multiplier is found to achieve 21 % reduction in delay, 63.3% reduction in area, and 72.3% reduction in power compared to the accurate array multiplier while yielding a visually acceptable blended image. Further, compared to a highspeed accurate multiplier that was directly synthesized using a logic synthesis tool, our proposed approximate array multiplier reports 9.7% reduction in delay, 60.6% reduction in area, and 64.7% less power. The multipliers were physically realized using a 32/28-nm CMOS technology.