Rotating DICOM file around z-axis

clear variables

az = 3.1415926536;
Rz = [cos(az) -sin(az) 0; sin(az) cos(az) 0; 0 0 1];



Y = dicomread('C:\Users\20182002\OneDrive - TU Eindhoven\Documents\AFSTUDEREN\Matlab\horizontal_flip\EPI02\IMG-0001-00015.dcm');

Y_rotation = Y*(Rz);

dicomwrite(Y_rotation, ("Image_flip.dcm"));

Hello,

I have a DICOM image (see attachment) which i love to rotate about the Z axis. For this I wrote a code (see above) but when I run it, I get the error: 'MTIMES (*) is not fully supported for integer classes. At least one argument must be scalar.'

So I was looking for a solution and found that you can use double() or single() to fix it. For me it would be double(Rz).

But this don't seem to work for me, can somebody help me?

[Stephen23]

"...you can use double() or single() to fix it. For me it would be double(Rz)."

RZ is already DOUBLE, so that command would do nothing.

What do you expect to occur when you multiply a 3x3 matrix with a 384x384 matrix?

[Anouk Baeten]

Yeah i found out this won't work indeed, but i need to rotate around the Z-axis. Is it maybe possible to expand the rotation/transformation matrix to the same size (384x384)?

Or how would you do this rotation?

[Stephen23]

"Or how would you do this rotation?"

IMROTATE

[Cris LaPierre]

As I said in my answer, you could use double, but that leads to a new error about a dimension mismatch error when multiplying your two arrays.

Answer 1

[Cris LaPierre]

Y is uint16 while Rz is double. However, converting Y to double will just lead to a dimension error with your matrix multiplication, since Y is 384x384 while Rz is 3x3.

Perhaps you want to use imrotate or imrotate3?

az = 3.1415926536;
Rz = [cos(az) -sin(az) 0; sin(az) cos(az) 0; 0 0 1];

unzip('https://www.mathworks.com/matlabcentral/answers/uploaded_files/1120005/IMG-0001-00015.dcm.zip');
Y = dicomread('IMG-0001-00015.dcm');
imshow(Y,[])

Y_rotation = imrotate(Y,rad2deg(az));
figure
imshow(Y_rotation,[])

[Anouk Baeten]

Thanks for the reply,

imrotate and imrotate3 I tried before this but that doesn't work (for my problem) because with that your rotate around the central axis. That is also why your result (Y_rotation) is upside down.

I need a rotation around the Z and that is why I came up with this.

[Anouk Baeten]

Can you help me with that?

[Cris LaPierre]

Where are you putting the Z axis? Whether it's in the center or a corner, I feel like visually the result is the same.