A BETTER DESCRIPTION OF METAMERIC EXPERIENCE OF LED CLUSTERS

摘要

There is a considerable chromaticity difference between instrumentally determined chromaticities after visually matching a broad band colour stimulus with narrow band colours produced by the light of red, green and blue LEDs (e.g. RGB LED cluster). To find the possible cause of earlier experienced colour mismatch phenomenon we carried out three different colour matching experiments (noted as experiment 'A', 'B' and 'C'). The first experiment (exp. 'A') used a setup where white reflecting samples were matched (Maxwellian-like match); while in experiments 'B' and 'C saturated self luminous colour fields had to be matched with two different primary RGB LED light sets (Maximum Saturation Technique-like match).An adequate measure of the goodness of a colorimetric system can be a Euclidean metric applied in an almost uniform chromaticity diagram like the CIE 1976 u'v', comparing the chromaticities of the visual and instrumental matches. The chromaticity differences can be halved if not the CIE standard colour matching functions (CIE 1931 CMFs) are used, but CMFs derived from cone fundamentals (Fundamental CMFs). By further modification of the Fundamental CMFs (Modified Fundamental CMFs) very good agreement could be obtained between the visual and instrumental matches. These tentative CMFs have to be further evaluated with a larger number of observers, before it can be recommended for general practice.