Patent ID: 6809740
Filing Date: 2004-10-26
Classification: G06F,H04N

Abstract:
In a system that has access to a sparse lookup table having lattice points that convert input data to output data, a method for converting samples of input data to output data by approximating, over a neighborhood of samples, a result that would be obtained using linear interpolation, comprising the steps for:obtaining a neighborhood of samples; for each sample in the neighborhood of samples: quantizing the sample by truncating from the sample one or more masked bits, such that one or more most significant index bits remain, wherein the value of the masked bits specifies a position of the sample with respect to a higher adjacent lattice point and a lower adjacent lattice point; and selectively incrementing or not incrementing the index bits based on the value of the masked bits to obtain dithered quantized index bits; and using the dithered quantized index bits as indices to the sparse lookup table, wherein the dithered quantized index bits, when considered over the neighborhood, index the lower adjacent lattice point rather than the higher adjacent lattice point at a relative frequency that is inversely proportional to ratio of the distance between the sample and the lower adjacent lattice point and the distance between the sample and the higher adjacent lattice point.