CVPRReviewImageProcessingFind3Dedges.convolution将kernel中心对称，invertedleft-rightandup-downcross-correlation不用convolutioncanbechangedtoamatrixmultiplicationIDFT-2DBoxfilterblur近看highpass，远看lowpassBoxfiltersaresimpleandfastbutmayresultinblockyeffects.Meanfilterspreserveedgesbetterbutcancauseblurring.Gau