The generation of an N-dimension look-up table used (N≧2) in conversion processing of input image data includes acquiring a value of the input image data for every channel corresponding to a respective dimension of the N-dimension look-up table by analyzing the input image data to be processed, determining an input value range of each dimension of the N-dimension look-up table based upon the acquired value, arranging a predetermined number of grid points in the determined input value range with regard to each dimension of the N-dimension look-up table, and setting an output value of each arranged grid point based upon desired image conversion processing.