DEPENDENT SCALAR QUANTIZATION OF COLOR IMAGES

Many image display devices can allow only a limited number of colors, called color palette, to be simultaneously displayed, In order to have faithful color reproduction of an image, the associated color palette must be suitably designed, This paper presents a dependent scalar qua ntization algorithm to design the color palette effectively, The depen dent scalar quantization algorithm consists of two procedures, the bit allocation and the recursive binary moment preserving thresholding. T he experimental results show that the dependent scalar quantization ca n reduce the computation complexity and its output images quality is a cceptable to the human eyes, A rule of the quantization order is also deduced under MSE criterion to obtain a dependent scalar quantizer whi ch has good performance as compared with some other algorithms, In add ition, an adaptive neighborhood-clustering algorithm, which searches t he neighboring color indices of input pixels iteratively, is proposed to further improve the performance of the dependent scalar quantizatio n algorithm, Finally, we introduce a color mapping method to reduce th e contouring effect when color palette size generated by the dependent scalar quantizer is small.