Practical Capture and Reproduction of Phosphorescent Appearance

Abstract

This paper proposes a pipeline to accurately acquire, efficiently reproduce and intuitively manipulate phosphorescent appearance. In contrast to common appearance models, a model of phosphorescence needs to account for temporal change (decay) and previous illumination (saturation). For reproduction, we propose a rate equation that can be efficiently solved in combination with other illumination in a mixed integro-differential equation system. We describe an acquisition system to measure spectral coefficients of this rate equation for actual materials. Our model is evaluated by comparison to photographs of actual phosphorescent objects. Finally, we propose an artist-friendly interface to control the behavior of phosphorescent materials by specifying spatio-temporal appearance constraints.

Spectral Mollification for Bidirectional Fluorescence

“…For typical camera shutter times fluroescence can be assumend to be instantaneous. Nalbach et al [NSR17] investigate phosphorescence, which is similar to fluorescence except that it can occur over up to several seconds, which requires additional care.…”

Bidirectional Rendering of Vector Light Transport

“…Recently, Nalbach et al . [NSR17] introduced a pipeline for acquiring and reproducing phosphorescent materials, including their temporal response. Finally, closer to us, Wilkie et al .…”

“…Hullin and colleages [HHA*10] presented a method to capture bi-spectral re-radiation matrices, which can be used for rendering fluorescent materials. Recently, Nalbach et al [NSR17] introduced a pipeline for acquiring and reproducing phosphorescent materials, including their temporal response. Finally, closer to us, Wilkie et al [WTP01] used bi-spectral re-radiation BRDFs within a forward path tracing, but do not describe how to extend this work to bidirectional methods.…”