When you do the demosaicing, and perhaps other steps, did you ever consider declaring the x-positions, spline parameters, ... as latent variables to estimate?

Consider a color histogram, then the logo (showing color oscillations) would have a wider spread and lower peaked histogram versus a correctly mapped (just the few colors plus or minus some noise) which would show a very thin but strong peak in colorspace. A a high-variance color occupation has higher entropy compared to a low-variance strongly centered peak (or multipeak) distribution.

So it seems colorspace entropy could be a strong term in a loss function for optimization (using RMAD).