PURPOSE: To provide a difference picture able to obtain an objective picture quality evaluation very close to a human subjective picture quality evaluation in a color picture.

CONSTITUTION: An evaluation picture and a reference picture with respect to the evaluation picture are read (SP1), brightness L, color differences u, v at each coordinate of the read evaluation picture and the read reference picture are calculated (SP2), differences of them between the evaluation picture and the reference picture ΔL, Δu, Δv are calculated at the same coordinates (SP4). Then a coefficient of a filter corresponding to the spatial frequency characteristic of the brightness L, a coefficient of a filter corresponding to the spatial frequency characteristic of the color difference u, and a coefficient of a filter corresponding to the spatial frequency characteristic of the color difference v are respectively multiplied with the differences ΔL, Δu, Δv to obtain difference pictures 1, 2, 3 corresponding to the L, u, v (SP5), and the obtained three difference pictures are synthesized by a prescribed weighting to generate one synthesized difference picture (SP6).