Block adaptive quantization of images

Results on block adaptive quantization of images using the adaptive dynamic range coding (ADRC) method are presented. In this method, the minimum and maximum intensities for each block are determined, and the pixels in the block are quantized with a uniform quantizer covering this range. The minimum and maximum values are transformed to midpoint and range values and then quantized and coded for transmission as side information. In order to reduce the visibility of blocking effects, ADRC can be applied to a subband decomposition of the image. This extension is called SADRC. Experimental results are presented for ADRC applied to the original image, as well as for four-band SADRC