To completely realize the filtering of a filter range having an arbitrary size by using a space filter having a finite filter range.
A filter range having an arbitrary filter size to which a predetermined filter coefficient group is assigned is prepared. This filter range is divided into sub-filter ranges less than the filter range of a space filter 17. Each time a filter coefficient group assigned to each of the sub-filter ranges is sequentially set in the space filter 17, the filtering of image data is carried out, and intermediate data are outputted by the space filter 17. The intermediate data are added to correct a difference between the pixels under consideration of the filter range having the arbitrary size and the pixels under consideration of the sub-filter range. Thus, it is made possible to calculate the filtering result of the filter range having the arbitrary size.
Yoshitake Hidetoshi
Takahiro Arita