Sensitivity Curve Approximation using Linear Algebra

Calibration of color cameras requires that a calibration pattern is recorded and color responsivity curves are estimated from the recorded data. Very often, these curves are sampled at discrete wavelength, so that the calibration problem can be written as a system of linear equations. The solution of the – usually overdetermined – problem is subject to a constrained optimization problem, as these curves need to have a certain shape. In this article we apply different methods to incorporate constraints into the estimation problem while still keeping the problem linear.