Lehrstuhl für Computergrafik

Improving Spectral Upsampling with Fluorescence

Lars König, Alisa Jung, Carsten Dachsbacher

8th Annual Workshop on Material Appearance Modeling (2020)

Improving Spectral Upsampling with Fluorescence
Comparison of the analytical (a, c, e) and dye-based (b, d, f) fluorescence model without interpolation. The cube grid layers for B = 0.161 (a, b) and B = 0.742 (c, d) reveal artifacts in the dye-based model. e, f): Chromaticity of all colors represented in a 32^3 coefficient cube with a maximum slope of 0.01, only showing colors with brightness of X+Y+Z ≥ 1.5.

Abstract

Modern photorealistic rendering simulates spectral behaviour of light. Since many assets are still created in different RGB color spaces, spectral upsampling of the RGB colors to a spectral representation is required to use them in a spectral renderer. Limiting the upsampled spectra to physically valid and natural, i.e. smooth, spectra results in a more realistic image, but decreases the size of the gamut of colors that can be recreated. In order to upsample wide gamut color spaces with colors outside the gamut of physically valid reflectance spectra, a previous approach added fluorescence to create accurate and physically valid representations. We extend this approach to increase the realism and accuarcy while considering memory and computation time.

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