How to get back Color image from gray scale image?

As I take Color image as input for processing in MATLAB, I have to convert my color image into gray image. Now, after applying various transformation how can I get Color Image from Gray image(The Image which I got after processing)?

Answer 1

[Sean de Wolski]

You could use rgb2ind with an applicable map. This will color based on the map though, not based on the original colors.

Your best bet to retain original colors is to index or do arithmetic with your original rgb image with whatever new information you've gotten from the grayscale analyses. It's impossible to get the original colors back otherwise, 3 unknowns, 1 equation.