Foveation-Based Wireless Soft Image Delivery

In image compression and transmission, two basic data redundancies can be identified and exploited: statistical redundancy and perceptual redundancy. Statistical redundancy has been studied for a very long time and has been exploited in most image coding schemes. However, perceptual redundancy has not yet been completely exploited. Furthermore, perceptual redundancy is difficult to exploit by using digital coding techniques because power allocation is performed at the bit level for digital coding. However, as one of one-size-fits-all technique, soft transmission is suitable to exploit the perceptual redundancy because its power allocation is directly applied at the pixel level instead of the bit level. In this paper, we propose a novel image transmission scheme, named FoveaCast , for single-input single-output or multi-input multi-output broadcast systems that effectively utilizes the foveation characteristic of human vision and analog coding techniques to achieve higher visual perceptual quality. Hence, our scheme possesses not only high visual perceptual quality but also graceful quality adaptation. Experimental evaluations show that compared with three existing digital schemes and two existing analog schemes, SoftCast and ParCast, FoveaCast achieves better visual perceptual performance. Meanwhile, it achieves a graceful quality variation along with channel variation, behaving just like SoftCast and ParCast.