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% RANGE = showIm (MATRIX, RANGE, ZOOM, LABEL, NSHADES )
%
% Display a MatLab MATRIX as a grayscale image in the current figure,
% inside the current axes. If MATRIX is complex, the real and imaginary
% parts are shown side-by-side, with the same grayscale mapping.
%
% If MATRIX is a string, it should be the name of a variable bound to a
% MATRIX in the base (global) environment. This matrix is displayed as an
% image, with the title set to the string.
%
% RANGE (optional) is a 2-vector specifying the values that map to
% black and white, respectively. Passing a value of 'auto' (default)
% sets RANGE=[min,max] (as in MatLab's imagesc). 'auto2' sets
% RANGE=[mean-2*stdev, mean+2*stdev]. 'auto3' sets
% RANGE=[p1-(p2-p1)/8, p2+(p2-p1)/8], where p1 is the 10th percentile
% value of the sorted MATRIX samples, and p2 is the 90th percentile
% value.
%
% ZOOM specifies the number of matrix samples per screen pixel. It
% will be rounded to an integer, or 1 divided by an integer. A value
% of 'same' or 'auto' (default) causes the zoom value to be chosen
% automatically to fit the image into the current axes. A value of
% 'full' fills the axis region (leaving no room for labels). See
% pixelAxes.m.
%
% If LABEL (optional, default = 1, unless zoom='full') is non-zero, the range
% of values that are mapped into the gray colormap and the dimensions
% (size) of the matrix and zoom factor are printed below the image. If label
% is a string, it is used as a title.
%
% NSHADES (optional) specifies the number of gray shades, and defaults
% to the size of the current colormap.
% Eero Simoncelli, 6/96.
%%TODO: should use "newplot"
function range = showIm( im, range, zoom, label, nshades );
%------------------------------------------------------------
%% OPTIONAL ARGS:
if (nargin < 1)
error('Requires at least one input argument.');
end
MLv = version;
if isstr(im)
if (strcmp(MLv(1),'4'))
error('Cannot pass string arg for MATRIX in MatLab version 4.x');
end
label = im;
im = evalin('base',im);
end
if (exist('range') ~= 1)
range = 'auto1';
end
if (exist('nshades') ~= 1)
nshades = size(colormap,1);
end
nshades = max( nshades, 2 );
if (exist('zoom') ~= 1)
zoom = 'auto';
end
if (exist('label') ~= 1)
if strcmp(zoom,'full')
label = 0; % no labeling
else
label = 1; % just print grayrange & dims
end
end
%------------------------------------------------------------
%% Automatic range calculation:
if (strcmp(range,'auto1') | strcmp(range,'auto'))
if isreal(im)
[mn,mx] = range2(im);
else
[mn1,mx1] = range2(real(im));
[mn2,mx2] = range2(imag(im));
mn = min(mn1,mn2);
mx = max(mx1,mx2);
end
if any(size(im)==1)
pad = (mx-mn)/12; % MAGIC NUMBER: graph padding
range = [mn-pad, mx+pad];
else
range = [mn,mx];
end
elseif strcmp(range,'auto2')
if isreal(im)
stdev = sqrt(var2(im));
av = mean2(im);
else
stdev = sqrt((var2(real(im)) + var2(imag(im)))/2);
av = (mean2(real(im)) + mean2(imag(im)))/2;
end
range = [av-2*stdev,av+2*stdev]; % MAGIC NUMBER: 2 stdevs
elseif strcmp(range, 'auto3')
percentile = 0.1; % MAGIC NUMBER: 0<p<0.5
[N,X] = histo(im);
binsz = X(2)-X(1);
N = N+1e-10; % Ensure cumsum will be monotonic for call to interp1
cumN = [0, cumsum(N)]/sum(N);
cumX = [X(1)-binsz, X] + (binsz/2);
ctrRange = interp1(cumN,cumX, [percentile, 1-percentile]);
range = mean(ctrRange) + (ctrRange-mean(ctrRange))/(1-2*percentile);
elseif isstr(range)
error(sprintf('Bad RANGE argument: %s',range))
end
if ((range(2) - range(1)) <= eps)
range(1) = range(1) - 0.5;
range(2) = range(2) + 0.5;
end
if isreal(im)
factor=1;
else
factor = 1+sqrt(-1);
end
xlbl_offset = 0; % default value
if (~any(size(im)==1))
%% MatLab's "image" rounds when mapping to the colormap, so we compute
%% (im-r1)*(nshades-1)/(r2-r1) + 1.5
mult = ((nshades-1) / (range(2)-range(1)));
d_im = (mult * im) + factor*(1.5 - range(1)*mult);
end
if isreal(im)
if (any(size(im)==1))
hh = plot( im);
axis([1, prod(size(im)), range]);
else
hh = image( d_im );
axis('off');
zoom = pixelAxes(size(d_im),zoom);
end
else
if (any(size(im)==1))
subplot(2,1,1);
hh = plot(real(im));
axis([1, prod(size(im)), range]);
subplot(2,1,2);
hh = plot(imag(im));
axis([1, prod(size(im)), range]);
else
subplot(1,2,1);
hh = image(real(d_im));
axis('off'); zoom = pixelAxes(size(d_im),zoom);
ax = gca; orig_units = get(ax,'Units');
set(ax,'Units','points');
pos1 = get(ax,'Position');
set(ax,'Units',orig_units);
subplot(1,2,2);
hh = image(imag(d_im));
axis('off'); zoom = pixelAxes(size(d_im),zoom);
ax = gca; orig_units = get(ax,'Units');
set(ax,'Units','points');
pos2 = get(ax,'Position');
set(ax,'Units',orig_units);
xlbl_offset = (pos1(1)-pos2(1))/2;
end
end
if ~any(size(im)==1)
colormap(gray(nshades));
end
if ((label ~= 0))
if isstr(label)
title(label);
h = get(gca,'Title');
orig_units = get(h,'Units');
set(h,'Units','points');
pos = get(h,'Position');
pos(1:2) = pos(1:2) + [xlbl_offset, -3]; % MAGIC NUMBER: y pixel offset
set(h,'Position',pos);
set(h,'Units',orig_units);
end
if (~any(size(im)==1))
if (zoom > 1)
zformat = sprintf('* %d',round(zoom));
else
zformat = sprintf('/ %d',round(1/zoom));
end
if isreal(im)
format=[' Range: [%.3g, %.3g] \n Dims: [%d, %d] ', zformat];
else
format=['Range: [%.3g, %.3g] ---- Dims: [%d, %d]', zformat];
end
xlabel(sprintf(format, range(1), range(2), size(im,1), size(im,2)));
h = get(gca,'Xlabel');
set(h,'FontSize', 9); % MAGIC NUMBER: font size!!!
orig_units = get(h,'Units');
set(h,'Units','points');
pos = get(h,'Position');
pos(1:2) = pos(1:2) + [xlbl_offset, 10]; % MAGIC NUMBER: y offset in points
set(h,'Position',pos);
set(h,'Units',orig_units);
set(h,'Visible','on'); % axis('image') turned the xlabel off...
end
end
return;