To execute area transformation close to an original picture by replacing positional information, which is not a DC component with respect to the whole picture in spite of being the DC component within a block, for an AC component so as to prevent different transformation due to small block division.

Visual distance information and number of pixels information are inputted to a pixel density deciding means 11 to calculate pixel density being the largest number of pixels per a visual angle 1. A DC shift setting means 13 shifts positional information within the block to an AC component when it is a DC component and replaces positional information, which is not the DC component with respect to the whole picture in spite of being the DC component within the block, for the AC component to output to a normalized frequency setting means 12. The means 12 calculates a normalized frequency by discrete cosine transformation DCT block size information and block inside positional information. Next, a visual frequency calculating means 14 calculates a visual frequency by pixel density and the normalized frequency, and a visual characteristic calculating means 16 substitutes it to a visual characteristic function H (f) to output the visual characteristic of a position. Thereby, area transformation close to the original picture is executed.