dicom_encode_jpeg_lossless.m
fdbeb459bbc4master

dicom_encode_jpeg_lossless.m
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			function [fragments, frames] = dicom_encode_jpeg_lossless(X, bits)
			%DICOM_ENCODE_JPEG_LOSSLESS Encode pixel cells using lossless JPEG.
			% [FRAGMENTS, LIST] = DICOM_ENCODE_JPEG_LOSSLES(X) compresses and
			% encodes the image X using baseline lossles JPEG compression.
			% FRAGMENTS is a cell array containing the encoded frames (as UINT8
			% data) from the compressor. LIST is a vector of indices to the first
			% fragment of each compressed frame of a multiframe image.
			%
			% See also DICOM_ENCODE_RLE, DICOM_ENCODE_JPEG_LOSSY.

			% Copyright 1993-2010 The MathWorks, Inc.


			% Use IMWRITE to create a JPEG image.

			classname = class(X);

			switch (classname)
			case {'int8', 'int16'}
			tmp = dicom_typecast(X(:), ['u' classname]);
			X = reshape(tmp, size(X));
			end

			numFrames = size(X,4);
			fragments = cell(numFrames, 1);
			frames = 1:numFrames;

			for p = 1:numFrames

			tempfile = tempname;
			imwrite(X(:,:,:,p), tempfile, 'jpeg', 'mode', 'lossless', 'bitdepth', bits);

			% Read the image from the temporary file.
			fid = fopen(tempfile, 'r');
			fragments{p} = fread(fid, inf, 'uint8=>uint8');
			fclose(fid);

			% Remove the temporary file.
			try
			delete(tempfile)
			catch
			warning(message('images:dicom_encode_jpeg_lossless:tempFileDelete', tempfile));
			end

			end