the meaning of colon in Matlab

Hello everyone,

I cannot understand the code below. Could you please be kind and help me?

fps = 1/8;

% Change to folder with images
cd('C:\Users\ZZHUI\Desktop\Bmp_DICOM\unnamed_2')
all_files = dir('*.dcm');

   for i = 1:size(all_files,1)
      info = dicominfo(all_files(i).name);
      imagematrix(i,:,:) = dicomread(info);

      DICOMimage(:,:) = imagematrix(i,:,:);

I cannot get the meaning of imagematrix(i,:,:) , and DICOMimage(:,:) = imagematrix(i,:,:)

Thanks!

Yang

Answer 1

[Image Analyst]

It means "all of that dimension", so A(:, 5) means all rows in column 5, and imagematrix(i, :, :) means the x dimension (if that's what it means) is "i" and you're taking all y and all z for which x == i. In other words, you're taking a y-z slice in the 3D image along the plane x=i.

Answer 2

[Azzi Abdelmalek]

 imagematrix(i,:,:)  is 3D matrix
 suppose you have 4 matrix 3x2 we can save all 4 matrix in one variable M
 M(:,:,1) is the first matrix 3x2,    
 M(:,:,2) is the second matrix 3x2
 ...
 M(:,:,4) is the fourth matrix 3x2
 the first  ":"  means all line
 the second ":" means all columns
 the third ":" means all matrix