save pig image

this is my code:

t = 'P10307';
u = 65;
n = 1;
for i = 1:12
  name = [t num2str(u) '.JPG'];
  A = imread(name);
  A = rgb2hsv(A);
  V = A(:,:,3);
  filename = ['LS0' num2str(n) 'AL'];
  imwrite(V,filename','pgm')

    u = u+1;
    n = n+1;
end

I have to obtain just 'V' component and I have to save it as 'pmg' , but an error occurs when I try to do this. What's the problem?

Thanks a lot for your answer. G. Rossi

Answer 1

[Thomas]

try

 filename = ['LS0' num2str(n) 'AL.pgm'];

imwrite(V,filename)

should work,

I think yours did not work because when you specify format pgm , the second string in imwrite is the colormap..

[Pinco]

thanks for you answer!

see comment below

[Thomas]

to open this image on my MAC I import LS01AL.pgm in MATLAB and use

imshow(LS01AL)

Answer 2

[Sean de Wolski]

Pigs are known to be stubborn occasionally, fortunately you're not trying to save a mule image.

Does this work?

imwrite(uint8(magic(10)),'pig.pgm','pgm')
imread('pig.pgm')

?

[Pinco]

i'm sorry for the title!!!

your command run, but if I open the image with textedit (I use Matlab on Mac) i see this:

P5 10 10 255

\cCJ3:(bPI79@)QX68?F/UW<>EGV] =DK4"LSZ*1!ARY[0 'BO

_a&-H

^`N#%,.5 dMT$+2;

Matlab reads this correctly... is it normal?

The same problem with solution by Thomas Anthony.

[Sean de Wolski]

You need to make sure you're using integer classes, hence why I wrapped uint8() around the above. It's not surprising to me that an image file appears as gibrish in a text editor. Try opening any other image in a text edit and you'll see the same thing. MATLAB knows the file format so it can read the binary correctly. Does it look good in another image viewer?

[Pinco]

With other program, such as Paint Shop Pro, i can see images correctly, but for my purpose i need a file with correct number.

Answer 3

[Pinco]

Now my code is:

t = 'P10307';
u = 65;
n = 1;
for i = 1:12
  name = [t num2str(u) '.JPG'];
  A = imread(name);
  A = rgb2hsv(A);
  V = A(:,:,3);
  filename = ['LS0' num2str(n) 'AL.pgm'];
  imwrite(V,filename,'pgm')

    u = u+1;
    n = n+1;
end

[Image Analyst]

I don't know. I don't use that format. I think you need to make sure that pgm accepts floating point images. Most formats don't, but like I said, I don't know about pgm. Why not save as a .mat file instead if you need to save a floating point image? Or else convert it to the range 0-255 and save it as a PNG image?

[Sean de Wolski]

It only likes integers.

[Pinco]

If I change "V = A(:,:,3);" with "V = A(:,:,3)*255;" it's the same.

I need a pgm file because my teacher, after, has to work with this file in a fortran program.