Foveated Wavelet Image Coding With Fuzzy Logic

This paper presents a method of the foveated wavelet image coding with fuzzy logic. Our objective is to maximize foveated wavelet image quality index (FWQI). With foveated visual sensitivity model, image areas are first prioritized. Image areas close to the foveated point will have higher priority than those, which are far away. The wavelet coefficients corresponding to different image areas are weighted differently based on their priorities. To achieve the objective, we use a fuzzy logic system and iterative method to select the image coding parameters, which are a number of weighted wavelet coefficients (NWC) and a quantization parameter (QP). There are two inputs and one output in the proposed fuzzy logic system. The inputs consist of a set of NWC and the targeted bit per pixel used for representing and for encoding foveated images, respectively. The output is a range of potential QP corresponding to the input NWC. The best QP giving highest FWQI is selected from the range. We iteratively change NWC and compute its best corresponding QP. NWC and QP maximizing FWQI will be chosen to encode foveated image. SPIHT codec is used to evaluate our proposed algorithm. Our simulation results show that the proposed scheme provides better image quality compared to previous works in both objective and subjective quality.