Access to the fits file channels

Hello Folks,

I have this fits file of size(300,300,3) I would like to acces to each channel alone and write it. Using this code I can access only to the first channel but not to the second and third one. Any idea please.

stokes = fitsread('stokes1.fits');

Iu = stokes(:,:,1);
Ip = stokes(:,:,2);
Theta = stokes(:,:,3);

fitswrite([Iu,Ip,Theta],'stokes.fits')

Answer 1

[Walter Roberson]

info = fitsinfo('stokes1.fits');
Size = info.PrimaryData.Size;
nchan = Size(3);
parts = cell(1,nchan);
for channel = 1 : nchan
   parts{channel} = fitsread(info, 'pixelregion', {[1 Size(1)], [1 Size(2)], [channel channel]})'
end

[assia assia]

Thank you for your feedback, but I have an error:

Expected FILENAME to be one of these types:

char, string

Instead its type was struct.

Error in fitsinfo (line 212)
fid              = openFile(filename);

Error in fitsread (line 103)
    info = fitsinfo(filename);

Error in PSNR_SSIM (line 18)
   parts{channel} = fitsread(info, 'pixelregion', {[1 Size(1)], [1 Size(2)], [channel channel]})'

[assia assia]

I add a line to your code and it's working now.

for the moment I would like to write and visualize each channel . I used this line but it writes for me only the last channel not the two previous one also.

stokes = fitsread('StokesParameters_Synthetic_Star_Gain_10.fits');
info = fitsinfo('StokesParameters_Synthetic_Star_Gain_10.fits')
Size = info.PrimaryData.Size
nchan = Size(3)
parts = cell(1,nchan);
for channel = 1 : nchan
   parts{channel} = fitsread('StokesParameters_Synthetic_Star_Gain_10.fits','PixelRegion', {[1 Size(1)], [1 Size(2)], [channel channel]})
end

fitswrite(parts{channel},'stokes5.fits','Compression','rice')

[Walter Roberson]

I had misread about the option to use an info structure instead of a file name.

As usual I recommend making the filename a variable.

fitsfile = 'StokesParameters_Synthetic_Star_Gain_10.fits';

info = fitsinfo(fitsfile);
Size = info.PrimaryData.Size;
nchan = Size(3);
parts = cell(1,nchan);
for channel = 1 : nchan
   parts{channel} = fitsread(fitsfile,'PixelRegion', {[1 Size(1)], [1 Size(2)], [channel channel]});
end

outdata = horzcat(parts{:});
fitswrite(outdata, 'stokes5.fits', 'Compression', 'rice');

[assia assia]

Thank you for your feedback.