Spectral reconstruction of fluorescent objects with mutual illumination effects.

An approach is proposed for appearance reconstruction of fluorescent objects with mutual illumination effects under different conditions of material and illumination. We focus on the problem of reconstructing a realistic scene appearance, including mutual illumination effects, under different conditions of materials and illumination. First, spectral images of two closely located fluorescent objects are acquired under different illumination directions. The observed images are then decomposed into five components. Each component is expanded into spectral composition functions and geometric factors. Second, aiming at effective appearance reconstruction, we define the reference geometric factors to be invariant representations of the geometric factors, independent of illumination. The reference factors are estimated by taking the models of reflectance, luminescence, and mutual illumination into account. A novel appearance is rendered with different fluorescence materials, different illumination conditions, and the corresponding geometric factor estimates. The spectral image is reconstructed as a linear sum of the five components, combining the spectral functions and the geometric factors at the level of each component. The accuracy of appearance reconstruction of fluorescent objects is examined in experiments in detail.