IOS: Divide the UIImageView image into shapes and change their colors

I am creating an iPhone application where I need to identify and decompose various forms (e.g. Wall, Chair, Book, etc.) in a UIImageView image and change their color. So far, I have implemented code that allows the user to select a color and apply it to a selected area (pixel base) using a gesture recognizer, but what I'm looking for is much more than what I did!

Is it possible to detect the various shapes available in this image and change their color?

Thank.