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function [datatx,h,w] = rdimage(filename,PictureComp) 
%RDIMAGE Reads a grey scale bmp file, suitable for cofdm transmission 
%	datatx = rdimage(filename,PicutreComp) 
%	filename is the filename of the bmp file to load. 
% 
%	PictureComp : Picture intensity compression. Fraction to  
%		compress the intensity of the image by. This is 
%		compresses the images so whites are darker and black 
%		is lighter. This is to modify the mapping of the final 
%		transmission mapping when using 256PSK. It increases  
%		the gap between black and white, to help prevent 
%		wrap around of black to white, in a noisy channel. 
%		Note : This is an optional parameter with a default 
%		setting of 1, giving no compression. 
%		 
%	datatx : 8bit words representing the intensity of each pixel. 
%		The output data is in a byte serial format, in a single row. 
% 
%	h : height of image in pixels 
%	w : width of the image in pixels 
 
%================================ 
%	Used functions: 
%	bmpread.m 
%===================== 
%	Modified: 
%	31/7/97	8:20am	rdimage.m 
%	Started work on the function 
% 
%	31/7/97 12:00pm rdimage. 
%	Fixed a bug with the ordering of the bits. The conversion 
%	to base 4,2,or 1 was causing the image to be incorrect. 
%	It had repetitions of the picture, each successively getting 
%	smaller, in an binary tree type arrangment. This was due 
%	to the msb => lsb being placed on separate symbols, but 
%	being recreated assumming they were side by side on the same  
%	symbol. The effect can be recreated by rotating leftover, and 
%	FileData using the ' operation. 
%	rdfile.m appears to work now. 
% 
%	31/7/97	3:00pm	rdimage.m 
%	The check for if the map and gray colors are the same keeps 
%	on having wierd errors, so I commented them out. 
% 
%	3/8/97	10:30am	rdimage.m 
%	Added the PictureComp parameter to allow for varying the  
%	mapping to help prevent roll over of black to white. Also added 
%	data averaging allowing duplicate data to be sent to reduce the 
%	error rate. 
%	 
%	12/8/97	7:30pm	rdimage.m 
%	Removed the DataAvg parameter as this is now done by the transmit  
%	function. Also removed the number base conversion, and the formatting 
%	of the data into symbols. All these are now done by the transmit routine. 
 
[x,map] = bmpread(filename); 
x=x-1;		%Change from 1-256 to 0-255; 
if nargin == 2, 
	%x=round((x/PictureComp)+(PictureComp-1)*128); 
	x = round((x-128)/PictureComp+128); 
end 
 
%if map ~= gray, 
%	error('The bmp to be loaded is not a gray scale image'); 
%end 
h = size(x,1); 
w = size(x,2); 
 
datatx = reshape(x',1,h*w);	%Put the data in a serial byte format