It is my understanding that you want to rescale(stretch) the 4th image such that only a selected portion (RGB part of the image) is displayed on the predefined axis.
A possible workaround could be:
- Accessing the 4th location in the plot by using the subplot function. For your example you can use "subplot(1, 4, 4)" to access the 4th location.
- Rescaling the image by changing the 'Xdata' and 'Ydata' property of the 'imshow' function.
- Use the 'imcrop' function to crop out the required part of the image.