Modeling and Analysis of Image Dependence and Its Implications for Energy Savings in Error Tolerant Image Processing

We present an analysis of the relationship between input images and energy consumption in error tolerant image processing. Under aggressive voltage scaling, the output image quality of image processing depends on input images for two reasons: 1) error tolerance among images is naturally disparate in terms of perceptual image quality assessment, and 2) the error rate under aggressive voltage scaling varies by input image types. Based on both effects, the supply voltage can be optimized for a given quality requirement so as to achieve ultralow power/energy dissipation. Our analysis demonstrates the significance of the accurate delay estimation, which depends on not only combinational inputs but also the previous state of the logic. We present a new sequential model for accurate error estimation. Based on the model, our experimental results demonstrate that different input image types lead to very different output quality. We also present the effect of process variation on the relationship between input image and output quality. The dependence of energy consumption on input images provides a new perspective for low-power multimedia and image processing system design.