X-Git-Url: https://git.creatis.insa-lyon.fr/pubgit/?p=CreaPhase.git;a=blobdiff_plain;f=octave_packages%2Fimage-1.0.15%2Fimadjust.m;fp=octave_packages%2Fimage-1.0.15%2Fimadjust.m;h=f4b7d3a33fd50d3d2800222b2e2611b471b1e6e2;hp=0000000000000000000000000000000000000000;hb=f5f7a74bd8a4900f0b797da6783be80e11a68d86;hpb=1705066eceaaea976f010f669ce8e972f3734b05
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+## 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 .
+##
+##
+## Based on old imadjust.m (GPL):
+## Copyright (C) 1999,2000 Kai Habel
+
+
+## -*- texinfo -*-
+## @deftypefn {Function File} @var{J}= imadjust (@var{I})
+## @deftypefnx {Function File} @var{J}= imadjust (@var{I},[@var{low_in};@var{high_in}])
+## @deftypefnx {Function File} @var{J}= imadjust (@var{I},[@var{low_in};@var{high_in}],[@var{low_out};@var{high_out}])
+## @deftypefnx {Function File} @var{J}= imadjust (..., @var{gamma})
+## @deftypefnx {Function File} @var{newmap}= imadjust (@var{map}, ...)
+## @deftypefnx {Function File} @var{RGB_out}= imadjust (@var{RGB}, ...)
+## Adjust image or colormap values to a specified range.
+##
+## @code{J=imadjust(I)} adjusts intensity image @var{I} values so that
+## 1% of data on lower and higher values (2% in total) of the image is
+## saturated; choosing for that the corresponding lower and higher
+## bounds (using @code{stretchlim}) and mapping them to 0 and 1. @var{J}
+## is an image of the same size as @var{I} which contains mapped values.
+## This is equivalent to @code{imadjust(I,stretchlim(I))}.
+##
+## @code{J=imadjust(I,[low_in;high_in])} behaves as described but uses
+## @var{low_in} and @var{high_in} values instead of calculating them. It
+## maps those values to 0 and 1; saturates values lower than first limit
+## to 0 and values higher than second to 1; and finally maps all values
+## between limits linearly to a value between 0 and 1. If @code{[]} is
+## passes as @code{[low_in;high_in]} value, then @code{[0;1]} is taken
+## as a default value.
+##
+## @code{J=imadjust(I,[low_in;high_in],[low_out;high_out])} behaves as
+## described but maps output values between @var{low_out} and
+## @var{high_out} instead of 0 and 1. A default value @code{[]} can also
+## be used for this parameter, which is taken as @code{[0;1]}.
+##
+## @code{J=imadjust(...,gamma)} takes, in addition of 3 parameters
+## explained above, an extra parameter @var{gamma}, which specifies the
+## shape of the mapping curve between input elements and output
+## elements, which is linear (as taken if this parameter is omitted). If
+## @var{gamma} is above 1, then function is weighted towards lower
+## values, and if below 1, towards higher values.
+##
+## @code{newmap=imadjust(map,...)} applies a transformation to a
+## colormap @var{map}, which output is @var{newmap}. This transformation
+## is the same as explained above, just using a map instead of an image.
+## @var{low_in}, @var{high_in}, @var{low_out}, @var{high_out} and
+## @var{gamma} can be scalars, in which case the same values are applied
+## for all three color components of a map; or it can be 1-by-3
+## vectors, to define unique mappings for each component.
+##
+## @code{RGB_out=imadjust(RGB,...)} adjust RGB image @var{RGB} (a
+## M-by-N-by-3 array) the same way as specified in images and colormaps.
+## Here too @var{low_in}, @var{high_in}, @var{low_out}, @var{high_out} and
+## @var{gamma} can be scalars or 1-by-3 matrices, to specify the same
+## mapping for all planes, or unique mappings for each.
+##
+## The formula used to realize the mapping (if we omit saturation) is:
+##
+## @code{J = low_out + (high_out - low_out) .* ((I - low_in) / (high_in - low_in)) .^ gamma;}
+##
+## @strong{Compatibility notes:}
+##
+## @itemize @bullet
+## @item
+## Prior versions of imadjust allowed @code{[low_in; high_in]} and
+## @code{[low_out; high_out]} to be row vectors. Compatibility with this
+## behaviour has been keeped, although preferred form is vertical vector
+## (since it extends nicely to 2-by-3 matrices for RGB images and
+## colormaps).
+## @item
+## Previous version of imadjust, if @code{low_in>high_in} it "negated" output.
+## Now it is negated if @code{low_out>high_out}, for compatibility with
+## MATLAB.
+## @item
+## Class of @var{I} is not considered, so limit values are not
+## modified depending on class of the image, just treated "as is". When
+## Octave 2.1.58 is out, limits will be multiplied by 255 for uint8
+## images and by 65535 for uint16 as in MATLAB.
+## @end itemize
+##
+## @seealso{stretchlim, brighten}
+## @end deftypefn
+
+## Author: Josep Mones i Teixidor
+
+## TODO: When Octave 2.1.58 is out multiply indices if input argument is
+## TODO: of class int* or uint*.
+
+function ret = imadjust (image, in, out, gamma)
+
+ if (nargin < 1 || nargin > 4)
+ usage ("imadjust(...) number of arguments must be between 1 and 4");
+ endif
+
+ if (nargin < 4)
+ gamma = 1; ## default gamma
+ endif
+
+ if !(ismatrix(image))
+ error ("imadjust(image,...) first parameter must be a image matrix or colormap");
+ endif
+
+ if (nargin==1)
+ in=stretchlim(image); ## this saturates 1% on lower and 1% on
+ out=[0;1]; ## higher values
+ endif
+
+ if (nargin==2)
+ out=[0;1]; ## default out
+ endif
+
+ if !((ismatrix(in) || isempty(in)) && (ismatrix(out) || isempty(out)) )
+ usage("imadjust(image,[low high],[bottom top],gamma)");
+ endif
+
+ if (isempty(in))
+ in=[0;1]; ## default in
+ endif
+
+ if (isempty(out))
+ out=[0;1]; ## default out
+ endif
+
+ simage=size(image);
+ if (length(simage)==3 && simage(3)==3)
+ ## image is rgb
+ [in, out, gamma]=__imadjust_check_3d_args__(in, out, gamma);
+
+ ## make room
+ ret=zeros(size(image));
+
+ ## process each plane
+ for i=1:3
+ ret(:,:,i)=__imadjust_plane__(image(:,:,i),in(1,i),in(2,i),out(1,i),out(2,i),gamma(1,i));
+ endfor
+
+ elseif (length(simage)==2)
+ if(simage(2)==3 && \
+ (size(in)==[2,3] || size(out)==[2,3] || size(gamma)==[1,3]) )
+ ## image is a colormap
+ [in, out, gamma]=__imadjust_check_3d_args__(in, out, gamma);
+
+ ret=[];
+ ## process each color
+ for i=1:3
+ ret=horzcat(ret,__imadjust_plane__(image(:,i),in(1,i),in(2,i),out(1,i),out(2,i),gamma(i)));
+ endfor
+
+ else
+ ## image is a intensity image
+ if( !isvector(in) || length(in)!=2 || !isvector(out) || length(out)!=2 || !isscalar(gamma) || (gamma<0) || (gamma==Inf) )
+ error("imadjust: on an intensity image, in and out must be 2-by-1 and gamma a positive scalar.");
+ endif
+ ret=__imadjust_plane__(image,in(1),in(2),out(1),out(2),gamma);
+ endif
+
+ else
+ error("imadjust: first parameter must be a colormap, an intensity image or a RGB image");
+ endif
+endfunction
+
+
+## This does all the work. I has a plane; li and hi input low and high
+## values; and lo and ho, output bottom and top values.
+## Image negative is computed if ho= li & I < hi) .* (lo + (ho - lo) .* ((I - li) / (hi - li)) .^ gamma);
+ ret = ret + (I >= hi) .* ho;
+endfunction
+
+
+## Checks in, out and gamma to see if they are ok for colormap and RGB
+## cases.
+function [in, out, gamma]=__imadjust_check_3d_args__(in, out, gamma)
+ switch(size(in))
+ case([2,3])
+ ## ok!
+ case([2,1])
+ in=repmat(in,1,3);
+ case([1,2]) ## Compatibility behaviour!
+ in=repmat(in',1,3);
+ otherwise
+ error("imadjust: in must be 2-by-3 or 2-by-1.");
+ endswitch
+
+ switch(size(out))
+ case([2,3])
+ ## ok!
+ case([2,1])
+ out=repmat(out,1,3);
+ case([1,2]) ## Compatibility behaviour!
+ out=repmat(out',1,3);
+ otherwise
+ error("imadjust: out must be 2-by-3 or 2-by-1.");
+ endswitch
+
+ switch(size(gamma))
+ case([1,3])
+ ## ok!
+ case([1,1])
+ gamma=repmat(gamma,1,3);
+ otherwise
+ error("imadjust: gamma must be a scalar or a 1-by-3 matrix.");
+ endswitch
+
+ ## check gamma allowed range
+ if(!all((gamma>=0)&(gamma