Patent ID: 7126611

Claim:
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 acts of: obtaining a sample of input data; quantizing the sample by truncating from the sample one or more masked bits, such that one or more most significant index bits remain, the index bits having a sufficient number of bits for indexing the sparse lookup table; comparing the one or more masked bits with a corresponding entry in a mask array to determine whether the value of a specific one of the masked bits indicates that the index bits are to be incremented prior to being used for indexing the lookup table; if the act of comparing indicates that the index bits are to be incremented, then incrementing the index bits, otherwise not incrementing the index bits; and then using the index bits as an index to the lookup table.