Linear models appear in many recent color constancy theories; however, they can play two quite different roles. They may either occur as a direct component of the computational strategy, as in the case of the Maloney-Wandell algorithm; or they may appear as necessary part of the theoretical development, but not as part of the computation perse, as in the case of algorithms based on spectral sharpening (Finlayson, Drew, Funt). This paper surveys recent work in color constancy and concludes that in many circumstances the second role may be more appropriate than the first.
Brian Funt, "Linear Models and Computational Color Constancy" in Proc. IS&T 3rd Color and Imaging Conf., 1995, pp 26 - 29, https://doi.org/10.2352/CIC.1995.3.1.art00007