--- /dev/null
+## 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, see <http://www.gnu.org/licenses/>.
+
+## -*- texinfo -*-
+## @deftypefn {Function File} {@var{B} = } blkproc (@var{A}, [@var{m},@var{n}], @var{fun})
+## @deftypefnx {Function File} {@var{B} = } blkproc (@var{A}, [@var{m},@var{n}], @var{fun}, ...)
+## @deftypefnx {Function File} {@var{B} = } blkproc (@var{A}, [@var{m},@var{n}], [@var{mborder},@var{nborder}], @var{fun}, @var{...})
+## @deftypefnx {Function File} {@var{B} = } blkproc (@var{A}, 'indexed', ...)
+## Processes image in blocks using user-supplied function.
+##
+## @code{B=blkproc(A,[m,n],fun)} divides image @var{A} in
+## @var{m}-by-@var{n} blocks, and passes them to user-supplied function
+## @var{fun}, which result is concatenated to build returning matrix
+## @var{B}. If padding is needed to build @var{m}-by-@var{n}, it is added
+## at the bottom and right borders of the image. 0 is used as a padding
+## value.
+##
+## @code{B=blkproc(A,[m,n],fun,...)} behaves as described above but
+## passes extra parameters to function @var{fun}.
+##
+## @code{B=blkproc(A,[m,n],[mborder,nborder],fun,...)} behaves as
+## described but uses blocks which overlap with neighbour blocks.
+## Overlapping dimensions are @var{mborder} vertically and @var{nborder}
+## horizontally. This doesn't change the number of blocks in an image
+## (which depends only on size(@var{A}) and [@var{m},@var{n}]). Adding a
+## border requires extra padding on all edges of the image. 0 is used as
+## a padding value.
+##
+## @code{B=blkproc(A,'indexed',...)} assumes that @var{A} is an indexed
+## image, so it pads the image using proper value: 0 for uint8 and
+## uint16 images and 1 for double images. Keep in mind that if 'indexed'
+## is not specified padding is always done using 0.
+##
+## @seealso{colfilt,inline,bestblk}
+## @end deftypefn
+
+## Author: Josep Mones i Teixidor <jmones@puntbarra.com>
+
+function B = blkproc(A, varargin)
+ if(nargin<3)
+ error("blkproc: invalid number of parameters.");
+ endif
+
+ ## check 'indexed' presence
+ indexed=false;
+ p=1;
+ if(ischar(varargin{1}) && strcmp(varargin{1}, "indexed"))
+ indexed=true;
+ p+=1;
+ if(isa(A,"uint8") || isa(A,"uint16"))
+ padval=0;
+ else
+ padval=1;
+ endif
+ else
+ padval=0;
+ endif
+
+ ## check [m,n]
+ if(!isvector(varargin{p}))
+ error("blkproc: expected [m,n] but param is not a vector.");
+ endif
+ if(length(varargin{p})!=2)
+ error("blkproc: expected [m,n] but param has wrong length.");
+ endif
+ sblk=varargin{p}(:);
+ p+=1;
+
+ ## check [mborder,nborder]
+ if(nargin<p)
+ error("blkproc: required parameters haven't been supplied.");
+ endif
+
+ if(isvector(varargin{p}) && isnumeric(varargin{p}))
+ if(length(varargin{p})!=2)
+ error("blkproc: expected [mborder,nborder] but param has wrong length.");
+ endif
+ sborder=varargin{p}(:);
+ p+=1;
+ else
+ sborder=[0;0];
+ endif
+
+ ## check fun
+ ## TODO: add proper checks for this one
+ if(nargin<p)
+ error("blkproc: required parameters haven't been supplied.");
+ endif
+
+ fun=varargin{p};
+ if(!isa(fun,"function_handle") &&
+ !isa(fun,"inline function") &&
+ !ischar(fun))
+ error("blkproc: invalid fun parameter.");
+ endif
+
+ ## remaining params are params to fun
+ ## extra params are p+1:nargin-1
+
+ ## First of all we calc needed padding which will be applied on bottom
+ ## and right borders
+ ## The "-" makes the function output needed elements to fill another
+ ## block directly
+ sp=mod(-size(A)',sblk);
+
+ if(any(sp))
+ A=padarray(A,sp,padval,'post');
+ endif
+
+ ## we store A size without border padding to iterate later
+ soa=size(A);
+
+ ## If we have borders then we need more padding
+ if(any(sborder))
+ A=padarray(A,sborder,padval);
+ endif
+
+ ## calculate end of block
+ eblk=sblk+sborder*2-1;
+
+ ## now we can process by blocks
+ ## we try to preserve fun return type by concatenating everything
+ for i=1:sblk(1):soa(1)
+ ## This assures r has the same class as returned by fun
+ r=feval(fun,A(i:i+eblk(1),1:1+eblk(2)),varargin{p+1:nargin-1});
+ for j=1+sblk(2):sblk(2):soa(2)
+ r=horzcat(r,feval(fun,A(i:i+eblk(1),j:j+eblk(2)),varargin{p+1:nargin-1}));
+ endfor
+ if(i==1) ## this assures B has the same class as A
+ B=r;
+ else
+ B=vertcat(B,r);
+ endif
+ endfor
+endfunction
+
+%!demo
+%! blkproc(eye(6),[2,2],inline("any(x(:))","x"))
+%! # Returns a 3-by-3 diagonal
+
+
+%!assert(blkproc(eye(6),[2,2],"sum"),blkproc(eye(6),[2,2],@sum));
+%!assert(blkproc(eye(6),[2,2],"sum"),blkproc(eye(6),[2,2],inline("sum(x)","x")));
+%!assert(blkproc(eye(6),[1,2],@sum),kron(eye(3),[1;1]));
+%!assert(blkproc(eye(6),[2,2],inline("any(x(:))","x")),eye(3)!=0);
+%!assert(blkproc(eye(6),[1,2],[1,1],inline("sum(x(:))","x")),[2,1,0;3,2,0;2,3,1;1,3,2;0,2,3;0,1,2]);
+%!assert(blkproc(eye(6),'indexed',[1,2],[1,1],inline("sum(x(:))","x")),[8,5,6;6,2,3;5,3,4;4,3,5;3,2,6;6,5,8]);
+%!assert(blkproc(eye(6),[2,3],[4,3],inline("sum(x(:))","x")),ones(3,2)*6);
+
+% Some int* and uint* tests
+%!assert(blkproc(eye(6),[2,2],inline("int8(sum(x(:)))","x")),eye(3,"int8")*2);
+
+% Padding is 0 even for indexed
+%!assert(blkproc(uint8(eye(6)),[1,2],[1,1],inline("sum(x(:))","x")),[2,1,0;3,2,0;2,3,1;1,3,2;0,2,3;0,1,2]);
+%!assert(blkproc(uint8(eye(6)),'indexed',[1,2],[1,1],inline("sum(x(:))","x")),[2,1,0;3,2,0;2,3,1;1,3,2;0,2,3;0,1,2]);
+%!assert(blkproc(uint16(eye(6)),[1,2],[1,1],inline("sum(x(:))","x")),[2,1,0;3,2,0;2,3,1;1,3,2;0,2,3;0,1,2]);
+%!assert(blkproc(uint16(eye(6)),'indexed',[1,2],[1,1],inline("sum(x(:))","x")),[2,1,0;3,2,0;2,3,1;1,3,2;0,2,3;0,1,2]);
+
+
+%
+% $Log$
+% Revision 1.5 2007/03/23 16:14:36 adb014
+% Update the FSF address
+%
+% Revision 1.4 2007/01/04 23:44:22 hauberg
+% Minor changes in help text
+%
+% Revision 1.3 2007/01/04 23:37:54 hauberg
+% Minor changes in help text
+%
+% Revision 1.2 2006/10/08 21:41:04 adb014
+% check isnumeric for vector and 'function_handle' not 'function handle' in isa test
+%
+% Revision 1.1 2006/08/20 12:59:31 hauberg
+% Changed the structure to match the package system
+%
+% Revision 1.5 2005/09/08 02:00:17 pkienzle
+% [for Bill Denney] isstr -> ischar
+%
+% Revision 1.4 2004/11/15 16:04:20 pkienzle
+% Fix tests for functions which return boolean matrices
+%
+% Revision 1.3 2004/09/03 17:49:37 jmones
+% Improved uint8 and uint16 padding expections
+%
+% Revision 1.2 2004/09/03 13:40:13 jmones
+% Check result has same class as function result, and improved fun param checking
+%
+% Revision 1.1 2004/08/15 19:27:46 jmones
+% blkproc: block process an image using user-supplied function
+%
+%
git://git.creatis.insa-lyon.fr / CreaPhase.git / blobdiff