US Patent 7586640 Signal processing unit

The invention achieves giving high color reproducibility to a color signal with reliability without substantially increasing circuit scale. A signal processing unit of the invention includes a color transformation part which multiplies an inputted color signal by a transformation matrix and an element setting part setting an element group of the transformation matrix according to every inputted color signal. The element setting part comprises an identification unit identifying a color of the color signal, a storage unit storing in advance optimum element groups for a predetermined number of reference signals, and an interpolation unit. The interpolation unit performs interpolation computing based on the input signal, two optimum element groups for two of the reference signals of colors close to a color of the color signal, and color relation between the color signal and the two reference signals to determine an element group to be set.