Spectral estimation and color appearance prediction of fluorescent materials

Bore-Kuen LeeFeng-Chi ShenChung-Hua UniversityDepartment of Electrical Engineering30 Tung ShiangHsinchu City 300TaiwanE-mail: bklee@chu.edu.twChun-Yen ChenIndustrial Technology Research InstituteOpto-Electronics and SystemsLaboratoriesBuilding 51, 195-8Section 4Chung Hsing RoadHsinchu County 310TaiwanAbstract. We present a low-cost, efficient, and industrially acceptablemethod to estimate the reflected and fluorescent spectral radiance fac-tors of a fluorescent object based on spectrophotometric data withoutusing a monochromator. With the measured spectral data, the coeffi-cients of the truncated Fourier series used to approximate these twospectral radiance factors are estimated using a weighted least squarealgorithm. The weighting function is defined as the sum of the CIE 1931standard x¯, y¯, and z¯color matching functions, so that the color differ-ence is minimized from the viewpoint of human vision. Three fluorescentsamples are used to verify our algorithm by predicting their color appear-ances under different sources.