Sandipan Dey walks through a paper on colorization and shows some examples:
Colorization is a computer-assisted process of adding color to a monochrome image or movie. In the paper the authors presented an optimization-based colorization method that is based on a simple premise: neighboring pixels in space-time that have similar intensities should have similar colors.
This premise is formulated using a quadratic cost function and as an optimization problem. In this approach an artist only needs to annotate the image with a few color scribbles, and the indicated colors are automatically propagated in both space and time to produce a fully colorized image or sequence.
In this article the optimization problem formulation and the way to solve it to obtain the automatically colored image will be described for the images only.
It’s an interesting approach.