matlab读写pgm文件

读文件

%function disp_pgm(pgm_image_name)
%不支持文件中有注释
pgm_image_name='tmp.pgm';
f = fopen(pgm_image_name,'r');
if f == -1
    error(['Could not open file ',pgm_image_name]);
end
[imgsize, num]=fscanf(f, 'P5\n%d\n%d\n255\n');
if num~=2,error('error num');end
image=[];
for h=1:imgsize(2)
    image=[image fread(f,imgsize(1),'uint8')];
end
image=image.';
fclose(f);
imshow(image);

写文件

% Load image
% image = imread(imageFile);

% If you have the Image Processing Toolbox, you can uncomment the following
%   lines to allow input of color images, which will be converted to grayscale.
if isrgb(image)
   image = rgb2gray(image);
end

[rows, cols] = size(image);

% Convert into PGM imagefile, readable by "keypoints" executable
f = fopen('tmp.pgm', 'w');
if f == -1
    error('Could not create file tmp.pgm.');
end
fprintf(f, 'P5\n%d\n%d\n255\n', cols, rows);
fwrite(f, image', 'uint8');
fclose(f);