pgm2x.m

支持向量机工具箱

function [x,width,height]=pgm2x(fname, normalize)
% PGM2X leads PGM image from file.
% [x,width,height]=pgm2x(fname, normalize)
%
% PGM2X loads an image from file which must be in the PGM 
%  format. The loaded image is returned as a column vector 
%  of doubles. If normalize is set to 1 then image values
%  will be normalized to range <0,1>.
% 
%  
% Input:
%  fname [string] file nam of the image.
%  normalize [int] if equal to 1 then output x is in range <0,1>.
%
% Output:
%  x [width x height] vector containg read image.
%  width [1x1] width of the image.
%  height [1x1] height of the image.
%
% See also X2PGM
%

% Statistical Pattern Recognition Toolbox, Vojtech Franc, Vaclav Hlavac
% (c) Czech Technical University Prague, http://cmp.felk.cvut.cz
% Written Vojtech Franc (diploma thesis)
% Modifications
% 27-sep-2001, V.Franc, argument normallized
% 26-feb-2001 V.Franc

if nargin < 2,
  normalize = 0;
end

fid=fopen(fname,'r');

line1=fgets(fid);
line2=fgets(fid);
line3=fgets(fid);


a = sscanf(line2,'%d');
width=a(1);
height=a(2);

prec= sscanf(line3, '%d');

if  prec==255,
  precision='uchar';
elseif prec==65535,
  precision='int16';
end

[x, count] = fread(fid,inf,precision);
fclose(fid);

if count ~= width*height,
  error('Invalid input format.');
  return;
end

x=x(:);

if normalize == 1,
   x=double(x)/prec;
end

return;