Proceedings PaperThe Application Of Human Visual System Models To Digital Color Image Compression
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A nonlinear mathematical model for the human visual system (HVS) was selected as a pre-processing stage for monochrome and color digital image compression. Rate distortion curves and derived power spectra were used to develop coding algorithms in the preprocessed "perceptual space." Black and white images were compressed to 0.1 bit per pel. In addition, color images were compressed to 1 bit per pel (1/3 bit per pel per color) with less than 1 percent mean square error and no visible degradations. Minor distortions are in-curred with compressions down to 1/4 bit per pel (1/2 bit per pel per color). It appears that the perceptual power spectrum coding technique "puts" the noise where one cannot see it. The result is bit rates up to an order of magnitude lower than those previously obtained with comparable quality. In addition, the model leads to an image quality metric which compares to subjective evaluations of an extensive image set with a correlation of 0.92.