Metamer density estimation using an identical ellipsoidal Gaussian mixture prior

We proposed an improved method for camera metamer density estimation. Camera metamer is a set of spectral reflectance of object surface which induce an identical RGB response of a color imaging devices such as a digital color camera and scanner. It is desirable for high fidelity color correction to calculate the set of metamers and then choose the optimal value in a standard color space. Previous methods adopted too simple models to represent the constraint of spectral reflectance. The set of metamers were over-estimated and it declined the accuracy of color correction. We modeled the constraint of spectral reflectance as an identical ellipsoidal Gaussian mixture distribution, and tested and compared the proposed model and two conventional models in a numerical experiment. It was found that the proposed model can represent accurately the underlying caved patterns within the given dataset and avoid generating inappropriate camera metamers. The accuracy of color correction was also evaluated supposing two commercial cameras and two standard illuminants. It was shown that higher accuracy color correction was achieved by adopting the proposed model.