How to change the column pixel values of a DICOM image and assign new values columnwise)?

I want to change the column-wise values of a DICOM image and assign them with new values to generate a new image. Columns (384) will be divided into 1-130, 131-230, 231-330, 331-384 and I want to multiply each (for example, all columns from 1-130 will be multiplied by * 0.15, to get a new value of the pixel). Please anyone may like to help. thanks

Answer 1

[Walter Roberson]

multfactor = repelem([0.15, 0.18, 0.04, 0.23], [130 100 100 54]);  %modify factors appropriately

newimage = oldimage .* multfactor;

If you need to write out the new image in the form of a dicom file, it can get a bit messy to get all of the details right. But use dicominfo() to get the information about the DICOM file, and pass the info in the dicomwrite() call.

[Rahman Ud Din]

Thank you Walter for your answer. As, I am new to MATLAB the second line (newimage = oldimage .* multfactor;), is showing an error when I run it, such as;

>> newimage = im1T2 .* multfactor;

I am beginner of MATLAB, please can you simplify further.

Thank you again.

[Walter Roberson]

what is the error?

what is size() of im1T1 and of multfactor?

[Rahman Ud Din]

Error using .*

Integers can only be combined with integers of the same

class, or scalar doubles.

However, the value for multfactor is 1 x 770 double and that of im1T2 is 384 x 384.

[Walter Roberson]

newimage = cast( double(im1T2) .* multfactor, 'like', Im1T2) ;

But how did multfactor get to be 770 long? The code I posted creates 384 long.

[Rahman Ud Din]

Thank you for your help. It worked.