imshow3D( I, varargin )

Display images in a certain custom 3D shape.

This function helps the user to display images in a certain custom 3D shape. It basically can be used as imshow(). When no shape is specified, the input image "I" will be plotted in a cylinder. The user can specify the shape in two different ways: 1) Specify the x,y,z coordinates or the shape or 2) Specify a radius line, which will be used to generate a revolution body.
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%
% EXAMPLES: I = peaks(); figure, imshow3D(I,'shape','sphere','colmap',hot(256));
%
% 1) Specify a shape with x,y,z coordinates:
%
% % Plot a cone
% r = (1:1000)';
% I = imresize(peaks(),[1000 1000]);
% nres = size(I,2);
% x = repmat(r,[1 nres]).*repmat(sin(linspace(0,2*pi,nres)),[numel(r) 1]);
% y = repmat(r,[1 nres]).*repmat(cos(linspace(0,2*pi,nres)),[numel(r) 1]);
% z = repmat((1:numel(r))',[1 nres]);
% figure, imshow3D(I,'shape',{x y z},'colmap',winter(256))
%
% % Plot a parallepiped:
% I = imresize(peaks(),[100 100]);
% r = ones(size(I,1),1);
% nres = size(I,2);
% t_aux = repmat(r,[1 nres/4]).*repmat(linspace(-1,1,nres/4),[numel(r) 1]);
% x = [repmat(r,[1 nres/4]), t_aux(:,end:-1:1), repmat(-r,[1 nres/4]) t_aux];
% y = [t_aux, repmat(r,[1 nres/4]), t_aux(:,end:-1:1), repmat(-r,[1 nres/4])];
% z = repmat((1:numel(r))',[1 nres]);
% figure, imshow3D(I,'shape',{x y z},'colmap',winter(256))
%
% % Plot a zig-zag shape:
% I = imresize(peaks(),[100 100]);
% r = ones(size(I,1),1);
% nres = size(I,2);
% x = [repmat(r,[1 nres/2]) zeros(numel(r),nres/2)];
% y = [repmat(r,[1 nres/4]) zeros(numel(r),nres/4) repmat(r,[1 nres/4]) zeros(numel(r),nres/4)];
% z = repmat((1:numel(r))',[1 nres]);
% figure, imshow3D(I,'shape',{x y z},'colmap',winter(256))
%
% % Plot a spiral
% nres = 100;
% I = imresize(peaks(),[nres nres]);
% r = repmat(linspace(1,10,nres),[size(I,1) 1]);
% x = repmat(sin(linspace(0,2*pi,nres)),[size(r,1) 1]).*r;
% y = repmat(cos(linspace(0,2*pi,nres)),[size(r,1) 1]).*r;
% z = repmat((1:size(r,1))',[1 nres]);
% figure, imshow3D(I,'shape',{x y z},'colmap',hot(256))
%
% % Plot a heart
% nres = 100;
% I = imresize(peaks(),[nres nres]);
% r = repmat([linspace(1,10,nres/2), linspace(10,1,nres/2)],[size(I,1) 1]);
% x = repmat(sin(linspace(0,2*pi,nres)),[size(r,1) 1]).*r;
% y = repmat(cos(linspace(0,2*pi,nres)),[size(r,1) 1]).*r;
% z = repmat((1:size(r,1))',[1 nres]);
% figure, imshow3D(I,'shape',{x y z},'colmap',hot(256))
%
% % Plot a flower
% npetals = 6; % Number of petals
% nres = 100;
% I = imresize(peaks(),[nres nres]);
% r = repmat(2 - sin(linspace(0,2*npetals*pi,nres)), [size(I,1) 1]);
% x = repmat(sin(linspace(0,2*pi,nres)),[size(r,1) 1]).*r;
% y = repmat(cos(linspace(0,2*pi,nres)),[size(r,1) 1]).*r;
% z = repmat((1:size(r,1))',[1 nres]);
% figure, imshow3D(I,'shape',{x y z},'colmap',winter(256))
%
%
% 2) Specify a shape only with a single line:
%
% % Plot a cone
% r = (1:1000)';
% figure, imshow3D(I,'shape',r,'colmap',winter(256))
%
% % Plot a Gaussian with mu=0 and sigma=2 using normpdf
% I = imresize(peaks(),[1000 1000]);
% r = normpdf(linspace(-10,10,size(I,1)),0,2)';
% figure, imshow3D(I,'shape',r,'colmap',winter(256))
%
% % Plot a Chi-Square distribution using pdf:
% I = imresize(peaks(),[1000 1000]);
% r = pdf('Chisquare',linspace(0,20,size(I,1)),4);
% figure, imshow3D(I,'shape',r,'colmap',winter(256))
%
%
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% Author: Manuel Blanco Valentin
% Industrial Engineer & Project Analyst
% e-mail: [e-mail]
%
% Centro Brasileiro de Pesquisas (CBPF) - CENPES - PETROBRAS
% Rio de Janeiro - Brazil - 2015
%
% LICENSE: This code is open-source, feel free to use it under your own
% responsability. Feel free to share this code, but please, do not delete
% this comments.
%
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