Mercurial > hg > octave-image
changeset 77:a3d6c751829d
new gtgetblk: get blocks from quatree decomposition
author | jmones |
---|---|
date | Wed, 11 Aug 2004 00:03:26 +0000 |
parents | 5d684cbaf092 |
children | 9f4b1926b58b |
files | qtgetblk.m |
diffstat | 1 files changed, 136 insertions(+), 0 deletions(-) [+] |
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new file mode 100644 --- /dev/null +++ b/qtgetblk.m @@ -0,0 +1,136 @@ +## Copyright (C) 2004 Josep Mones i Teixidor +## +## This program is free software; you can redistribute it and/or modify +## it under the terms of the GNU General Public License as published by +## the Free Software Foundation; either version 2 of the License, or +## (at your option) any later version. +## +## This program is distributed in the hope that it will be useful, +## but WITHOUT ANY WARRANTY; without even the implied warranty of +## MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the +## GNU General Public License for more details. +## +## You should have received a copy of the GNU General Public License +## along with this program; if not, write to the Free Software +## Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA 02111-1307 USA + +## -*- texinfo -*- +## @deftypefn {Function File} {[@var{vals}] = } qtgetblk (@var{I},@var{S},@var{dim}) +## @deftypefnx {Function File} {[@var{vals},@var{idx}] = } qtgetblk (@var{I},@var{S},@var{dim}) +## @deftypefnx {Function File} {[@var{vals},@var{r},@var{c}] = } qtgetblk (@var{I},@var{S},@var{dim}) +## Obtain block values from a quadtree decomposition +## +## [vals]=qtgetblk(I,S,dim) returns a dim-by-dim-by-k array in +## @var{vals} which contains the dim-by-dim blocks in the quadtree +## decomposition (@var{S}, which is returned by qtdecomp) of @var{I}. If +## there are no blocks, an empty matrix is returned. +## +## [vals,idx]=qtgetblk(I,S,dim) returns @var{vals} as described above. +## In addition, it returns @var{idx}, a vector which contains the linear +## indices of the upper left corner of each block returned (the same +## result as find(full(S)==dim)). +## +## [vals,r,c]=qtgetblk(I,S,dim) returns @var{vals} as described, and two +## vectors, @var{r} and @var{c}, which contain the row and column +## coordinates of the blocks returned. +## +## @end deftypefn +## @seealso qtdecomp + +## Author: Josep Mones i Teixidor <jmones@puntbarra.com> + +function [varargout] = qtgetblk(I, S, dim) + if (nargin!=3) + usage("[vals,r,c]=qtgetblk(I,S,dim), [vals,idx]=qtgetblk(I,S,dim)"); + endif + if (nargout>3) + usage("[vals,r,c]=qtgetblk(I,S,dim), [vals,idx]=qtgetblk(I,S,dim)"); + endif + + ## get blocks + [i,j,v]=spfind(S); + + ## filter the ones which match dim + idx=find(v==dim); + + if(length(idx)==0) + for i=1:nargout + varargout{i}=[]; + endfor + else + r=i(idx); + c=j(idx); + + ## copy to a dim-by-dim-by-k array + vals=zeros(dim,dim,length(idx)); + for i=1:length(idx) + vals(:,:,i)=I(r(i):r(i)+dim-1,c(i):c(i)+dim-1); + endfor + + varargout{1}=vals; + + if(nargout==3) + varargout{2}=r; + varargout{3}=c; + elseif(nargout==2) + varargout{2}=(c-1)*rows(I)+r; + endif + endif +endfunction + + +%!demo +%! [vals,r,c]=qtgetblk(eye(4),qtdecomp(eye(4)),2) +%! % Returns 2 blocks, at [1,3] and [3,1] (2*2 zeros blocks) + +%!shared A,S,v8a,v4a,v2a,v8b,v4b,v2b,v8c,v4c,v2c,i8,i4,i2,r8,r4,r2,c8,c4,c2 +%! A=[ 1, 4, 2, 5,54,55,61,62; +%! 3, 6, 3, 1,58,53,67,65; +%! 3, 6, 3, 1,58,53,67,65; +%! 3, 6, 3, 1,58,53,67,65; +%! 23,42,42,42,99,99,99,99; +%! 27,42,42,42,99,99,99,99; +%! 23,22,26,25,99,99,99,99; +%! 22,22,24,22,99,99,99,99]; +%! S=qtdecomp(A,10); +%! [v8a]=qtgetblk(A,S,8); +%! [v4a]=qtgetblk(A,S,4); +%! [v2a]=qtgetblk(A,S,2); +%! [v8c,i8]=qtgetblk(A,S,8); +%! [v4c,i4]=qtgetblk(A,S,4); +%! [v2c,i2]=qtgetblk(A,S,2); +%! [v8b,r8,c8]=qtgetblk(A,S,8); +%! [v4b,r4,c4]=qtgetblk(A,S,4); +%! [v2b,r2,c2]=qtgetblk(A,S,2); +%! [v8c,r8,c8]=qtgetblk(A,S,8); +%! [v4c,r4,c4]=qtgetblk(A,S,4); +%! [v2c,r2,c2]=qtgetblk(A,S,2); + +%!assert(v8a,[]); +%!assert(v8a, v8b); +%!assert(v8a, v8c); +%!assert(v4a, v4b); +%!assert(v4a, v4c); +%!assert(v2a, v2b); +%!assert(v2a, v2c); + +%!# Workaround to eye(3,A(1:4,1:4),A(5:8,5:8)) which won't work for Octave <= 2.1.57 +%!test +%! R=zeros(4,4,2); +%! R(:,:,1)=A(1:4,1:4); +%! R(:,:,2)=A(5:8,5:8); +%! assert(v4a,R); + +%!assert(i8,[]); +%!assert(i4, find(full(S)==4)); +%!assert(i2, find(full(S)==2)); + +%!assert(r8,[]); +%!assert(c8,[]); +%!assert(r4,[1;5]); +%!assert(c4,[1;5]); +%!assert(r2,[7;5;7;1;3;1;3]); +%!assert(c2,[1;3;3;5;5;7;7]); + + +