PURPOSE: To prevent the deterioration in picture quality by dividing a high resolution picture signal into a video memories of standard resolution, and storing them.

CONSTITUTION: The high resolution picture 10 is divided equally into four to form four screens 12, 14, 16 and 18, each is D/A-converted at a D/A converter to form a signal S1 for one screen's share, which is stored in memories 20, 22. The picture signal at the boundary with an adjacent sub-frame is stored in a memory 30 as a digital signal. The digital picture of each sub-frame is inputted to a histogram processor 26, the luminance distribution is obtained and stored in the memory 30. In the restorating method, the analog information is read out from the memories 20, 22, and converted into digital signals, the luminance distribution of this signal is obtained and the luminance is corrected so as to minimize the difference with the luminance distribution stored in the memory 30. The positioning is attained based on the picture signal of the boundary part read out from the memory 30.