save .TIFF file

I have an image (medical image) stocked as .TIFF file, when I read it I’ve found 4 matrix the first, the second and the third one are the RGB components of my image the fourth one is a binary matrix (contains only 1 values), I dont know what is it. I’ve denoised it but the problem is : -when I save it I got 000 values (black image) but when I open it under matlab I see that it is not an empty matrix this is my code :

t = Tiff([source2,'',num2str(v)],'w');
tagstruct.ImageLength     = 1000;
tagstruct.ImageWidth      = 1024;
tagstruct.Photometric     = Tiff.Photometric.RGB;
tagstruct.BitsPerSample   = 32;
tagstruct.SamplesPerPixel = 4;
tagstruct.RowsPerStrip    = 1000;
tagstruct.ExtraSamples    =Tiff.ExtraSamples.AssociatedAlpha;
tagstruct.PlanarConfiguration = Tiff.PlanarConfiguration.Chunky;
tagstruct.Software        = 'MATLAB';
tagstruct.SampleFormat=Tiff.SampleFormat.IEEEFP;
t.setTag(tagstruct);
t.write(single(Iy_d));
t.close();

I want to read the head of the file in order to check my BitsPerSample but I couldn’t

Xn= imread([source,'', num2str(v)],'tif')

I got this error :

info = imfinfo(Xn);
Error using imfinfo (line 80)
Expected FILENAME to be one of these types:

char

Instead its type was uint8

this make me confused because it shouldn't be uint8 !, So I convert it to double

Xn=im2double(imread([source,'', num2str(v)],'tif'))

But without any avail

[Stephen23]

The fourth matrix is the alpha channel (i.e. opacity/transparency), which means the image data is not just RGB but actually RGBA.

[Soum]

Thank you I didn't know before what is an RGBA image. I'll try based on this information

Answer 1

[Walter Roberson]

imfinfo needs to be applied to the image file name, not to what was read in from the file.