Read a 3-D MRI volume. Use the squeeze function to remove any singleton dimensions.

load mri;
D = squeeze(D);

Display the volume in a display panel.

fullViewPnl = uipanel(figure,'Title','Original Volume');
volshow(D,'Parent',fullViewPnl);

Specify the target size of the cropping window.

targetSize = [64 64 10];

Create a random crop window that crops the input volume from a randomly-selected position.

win = randomCropWindow3d(size(D),targetSize);

Crop the volume using the random crop window.

Dcrop = imcrop3(D,win);

Display the cropped volume in a display panel.

fullViewPnl = uipanel(figure,'Title','Cropped Volume');
volshow(Dcrop,'Parent',fullViewPnl);