In terms of correlation to the spectral data base SOCS (Standard Object Colour Spectra Database for Colour Reproduction Evaluation), computer simulation was employed to compare five camera quality indexes: CQF (Color Quality Factor) from Neugebauer, Goodness from Vora and Trusell, Squared Difference from ISO 17321 WD1.1, RMS (Root Mean Square) from ISO17321 WD4, and Camera Rendering Indexes (Ra: Average CRI, and Ri: Special CRI) from Hung. Based on the assumption that SOCS encompasses the spectral reflectance of real objects, SOCS was used to simulate real-world spectra. To avoid the disputed population problem of spectral reflectance in SOCS, we used color differences (ΔE*ab) containing 95.5%, 99.7%, and 100% (i.e. worst ΔE*) of the SOCS data, as well as a simple average, as references. Applied to thirteen sets of camera sensitivities, Average CRI gave correlation coefficients of greater than 0.95 against 95.5%, 99.7%, and average ΔE*, and Special CRI gave the best correlation coefficient with the worst ΔE* among these quality indexes. Thus, Average CRI appears to be a good index for the evaluation of a camera's colorimetric quality.
Po-Chieh Hung, "Comparison of Camera Quality Indexes" in Proc. IS&T 8th Color and Imaging Conf., 2000, pp 167 - 171, https://doi.org/10.2352/CIC.2000.8.1.art00031