A camera outputs an image $A$ that is a linear combination of two uncorrelated images $B$ and $C$:
$$A = B + kC$$
Images $A$ and $C$ are known; the unknowns here are $B$ and a scalar coefficient $k$ that varies the intensity of $C$.
Is there a way to retrieve $B$? I could use $A$ and $C$ as separate sources and apply the ICA algorithm, but I think that it's an overkill in this case, and there should be something simpler. Any suggestion? (I'm using OpenCV to process the images, but I can implement non-OpenCV algorithms if I need to.)