function?[z?zx1?zx2]?=?ckr2_regular（y?h?r?ksize）
%?[CKR2_REGULAR]
%?The?second?order?classic?kernel?regression?function?for?regularly?sampled
%?data.
%
%?[USAGE]
%?[z?zx1?zx2]?=?ckr2_regular（y?h?r?ksize）
%
%?[RETURNS]
%?z?????:?the?estimated?image
%?zx1???:?the?estimated?gradient?image?along?the?x1?direction?（vertical
%????????direction）
%?zx2???:?the?estimated?gradient?image?along?the?x2?direction?（horizontal
%????????direction）
%
%?[PARAMETERS]
%?y?????:?the?input?image
%?h?????:?the?global?smoothing?parameter
%?r?????:?the?upscaling?factor?（“r“?must?be?an?integer?number）
%?ksize?:?the?size?of?the?kernel?（ksize?x?ksize?and?“ksize“?must?be
%?????????an?odd?number）
%
%?[HISTORY]
%?June?16?2007?:?created?by?Hiro
%?Apr??14?2008?:?the?transpose?operator?is