How to blend image and label image

I have an colored RGB image and a 'label image' tells the object class. How do I combine these 2 to make the output look like the image below (without the white squiggly lines).

Answer 1

[Akira Agata]

If you already have label matrix for your RGB image, the last part of the following example will help.

-> Marker-Controlled Watershed Segmentation