Metameric failure assessment and reduction between RGB and laser phosphor projectors

Abstract

Metameric failure is commonly observed when different types of displays reproduce the same color, as it is defined by a colorimetry system, but the outputs do not match visually. Metameric failure is impacted by the used colorimetry system and the relation between the involved displays' spectral power distributions (SPDs). In this work, we assess the metameric failure between the upcoming types of theatrical projectors, RGB laser, and laser phosphor (LaPH) and propose a method to reduce it. Our analysis starts by evaluating the performance of existing colorimetry systems in terms of metameric failure reduction. Among the colorimetry systems tested, the CIE 2006 2° (CIE06 2°) system resulted in the least observed metameric failure for a large portion of the participants but not their absolute majority (>50%). The limited performance of existing colorimetry systems led us to questioning the feasibility of successful perceptual color matching between the two projectors. To explore and potentially rule‐out this scenario, we performed a subjective color matching experiment. The analysis of the results revealed the key role that the projectors' SPD differences play on color matching. Based on the observations of the first two studies, we propose a novel colorimetry system that reduces further than existing colorimetry the systems the metameric failure between RGB and LaPH projectors. Our proposed system is a modified version of CIE06–2° that accounts for the spectral differences of the two light sources. Evaluation showed that our solution outperforms existing colorimetry systems.

Measuring Subjective Differences Objectively

“…By combining the parametric color matching functions (CMFs) with the United Nations World Population Prospect, 4 it is possible to calculate worldwide, age‐weighted CMFs, color differences, and an OM index. Other modified CMFs have been proposed for personalized color imaging 5 and for comparison of displays using different light‐emitting technologies, such as laser displays 6 and professional monitors 7 . However, these modifications either were designed for specific technologies (not for WCG displays in general), or they were not verified for a large population.…”