Please tell me the best way to load .Raw ct image into MATLAB?

What is the recommended approach for loading a CT scan image of a rock with dimensions of 1000x1000x1000 Unit8 in .raw format into MATLAB for image processing, particularly for those who are new to this field? Could someone please provide a comprehensive guide, starting from the basics, that can be easily followed by beginners? Your expert guidance on this matter would be greatly appreciated. Thank you.

[Jan]

There is no unique definition of a .raw format. Remember that ".raw" is just a file extension, which can be set freely by any software. So find out at first, which format these files really have.

[Jahanzeb Tariq]

Thank you for your reply. I highly appreciate that. I kind of converted it into tiff format using image J and loaded using imread, but please tell me What could be the possible reasons for getting an error message indicating that the order of an image loaded into MATLAB is 1000x1000 instead of the expected 1000x1000x1000 dimensions, despite the image having three dimensions? Are there any recommended approaches or functions to use when loading 3D images into MATLAB to avoid such errors?

Answer 1

[Cris LaPierre]

Please share the code you are using and the full error message (all the red text).

If you have a 3D tiff image, I think you should be using tiffreadVolume instead of imread. It sounds like imread is only loading a single image and not the volume.

[Jahanzeb Tariq]

Thank you sir. It got fixed. i was using imread function to read 3d tiff file. thank you again. if you don't mind please could you tell me how to view this alos... or the viewing is the same for all type of images?

[Cris LaPierre]

I've never worked with 3D tiffs, but I would suspect any of the regular image viewing functions would work for a single plane of your data (see Sulaymon Eshkabilov's answer). You might be able to view the entire volume using the Volume Viewer app, and perhaps view individual slices using the Slice Viewer app.

[Jahanzeb Tariq]

I thank you all for your reply. I would like to also ask is there a function for "non local means" filter like gaussian filer? if so please do tell me the methodology to implement it on a 3d tiff file. thank you

[Cris LaPierre]

The only function in MATLAB I'm aware of for this is imnlmfilt., but is for a single image, not a 3D volume.

You might find solutions others have shared in the File Exchange.

• https://www.mathworks.com/matlabcentral/fileexchange/27395-fast-non-local-means-1d-2d-color-and-3d
• https://www.mathworks.com/matlabcentral/fileexchange/93720-fast-3d-non-local-means-filtering-using-convolutions-cpu-gpu
• https://www.mathworks.com/matlabcentral/fileexchange/43901-fast-and-robust-nonlocal-means-denoising

Answer 2

[Sulaymon Eshkabilov]

Use image(), imshow(), imagesc():

% To view Tiff image:
A = tiffreadVolume('TIFF_Image.tiff');
% image()
image(A(:,:,1))      % View Layer 1
% imshow()
imshow(A(:,:,2))      % View Layer 2
% imagesc()
imagesc(A(:,:,3))      % View Layer 3