New Method for Measuring an Optical Property of a Sample Treated by FWA

摘要

In this article, a new method for measuring a total spectral radiance factor of a FWA-treated sample illuminated by a specific standard illuminant is introduced. The method replaces an unstable real fluorescent standard by a bi-spectral luminescent radiance factor data, which works as a virtual fluorescent standard (VFS) by knowing spectral intensity distributions of illuminations applied to the sample. The method utilizes two illuminations I_1 and I_2 whose relative spectral intensity distributions are different from each other and synthesizes a virtual illumination presenting the identical fluorescent spectral radiance factor to that presented by the standard illuminant with the VFS of the specific bi-spectral luminescent radiance factor by linearly combining I_1 and I_2 with the suitable weighting factors. The applicability of the method is examined in principle by comparing ISO brightness and CIE whiteness index of fluorescent standard paper as a test sample obtained by this new method to the assigned values.