METHOD FOR GENERATING A FAST INVERSE TABLE

A large set of image data values are associated with a smaller set of values, such as color palette look-up table (LUT) indices, to create an inverse table. The larger set of image data values address into the inverse table. The inverse table is simulated as a symmetrical N-dimensional structure in computer memory, with N being the color dimension of the image data values. Generally, a set of star spaces in the structure are captured by the color palette LUT indices; the capturing is based on some relationship such as the relationship between the image data values and the color palette values indexed by the color palette LUT indices. The remainder of the structure spaces are captured by performing a uniform and iterative expansion away from each star space, capturing each uncaptured space encompassed by the expansion until all spaces are captured. The capturing of a space by a particular star corresponds to the entry of the capturing star value (color palette LUT index) into the inverse table at an address corresponding to the captured space. Using this type of iterative process, the inverse table is rapidly filled with color palette LUT indices, which, in turn, identify good approximations of the image data values by the color palette values in the LUT.