data2im.m

这是我找到的一个模式识别工具箱

%DATA2IM Convert PRTools dataset or datafile to image
%
%		IM = DATA2IM(A,J)
%		IM = DATA2IM(A(J,:))
%
% INPUT
%		A     Dataset or datafile containing images
%   J     Desired images
%
% OUTPUT
%		IM    If A is dataset, IM is a X*Y*N*K matrix with K images.
%         K is the number of images (length(J))
%					N is the number of bands per image.
%					N = 3 for RGB images, N = 1 for gray value images.
%
%         If A is a datafile, IM is a cell array of K images.
%
% DESCRIPTION
% An image, or a set of images stored in the objects or features of the
% dataset A are retrieved and returned as a 3D matrix IM. In case A is a
% datafile the images are stored in a cell array, except when a single
% image is requested.
%
% SEE ALSO
% DATASETS, IM2OBJ, IM2FEAT

% Copyright: R.P.W. Duin, [e-mail]
% Faculty EWI, Delft University of Technology
% P.O. Box 5031, 2600 GA Delft, The Netherlands

% $Id: data2im.m,v 1.9 2008/09/02 09:21:05 duin Exp $

function im = data2im(a,J)

	prtrace(mfilename);
	
	if nargin > 1, a = a(J,:); end									 
	if isdatafile(a)
		m = size(a,1);
		im = cell(1,m);
		for j=1:m
			%im{j} = readdatafile(a,1,0);
			im{j} = feval(mfilename,dataset(a(j,:)));
		end
		if m==1
			im = im{1};
		end
		return
	end

	a = testdatasize(a); % Oeps, datafiles are first converted to datasets
	                     % and then to images. This can be done better!
											 
	%isdataim(a);			% Assert that A contains image(s).

	data = +a;				% Extract data from dataset, for computational advantage.
	[m,k] = size(a); [objsize,featsize] = get(a,'objsize','featsize');

		
	% Reshape data into output array.

	if (isfeatim(a))	
		% A contains K images stored as features (each object is a pixel).
		if length(objsize) == 2
			im = zeros(objsize(1),objsize(2),k);
			for j = 1:k
				im(:,:,j) = reshape(data(:,j),objsize(1),objsize(2));
			end
		elseif length(objsize) == 3
			im = zeros(objsize(1),objsize(2),k,objsize(3));
			for j = 1:k
				im(:,:,j,:) = reshape(data(:,j),objsize(1),objsize(2),objsize(3));
			end
		else
			error('Unable to handle these images')
		end
			
	else							
		
		% A contains M images stored as objects (each feature is a pixel).
		if length(featsize) == 2
			im = zeros(featsize(1),featsize(2),1,m);
			for j = 1:m
				im(:,:,1,j) = reshape(data(j,:),featsize(1),featsize(2));
			end
		elseif length(featsize) == 3
			im = zeros(featsize(1),featsize(2),featsize(3),m);
			for j = 1:m
				im(:,:,:,j) = reshape(data(j,:),featsize(1),featsize(2),featsize(3));
			end
		else
			error('Unable to handle these images')
		end
	end

return