Registration of joint geometric and radiometric image deformations

We consider the problem of object registration where the observation and template differ both geometrically and radiometrically. The type of radiometric deformations we consider falls into the general framework of color constancy, and the geometric deformations are affine. Since the registration procedure employs the intensity information in both the template and observation, a solution to the color constancy problem have to be established jointly with a solution to the problem of estimating the geometric transformation. We show that the original high-dimensional non-convex search problem, that needs to be solved in order to register the observation to the template, can be replaced by an equivalent problem, expressed in terms of a sequence of two linear systems of equations. A solution to this sequence provides an exact solution to the registration problem.