1. A digital filter for image processing, the digital filter comprising: a decomposing unit that obtains subband signals by performing multiresolution decomposition on image data by using a broad-sense pinwheel framelet that is a set of an approximate filter with no orientation and a plurality of detail filters with respective orientations, and that has a degree; and a reconstructing unit that obtains reconstructed image data by reconstructing an image by summing the subband signals obtained by the decomposing unit; wherein the reconstructing unit generates the reconstructed image data by attenuating or amplifying a subband signal corresponding to at least one of filters that have predetermined frequency characteristics and/or a predetermined orientation among the filters.