Efficient Resampling, Compression and Rendering of Metallic and Pearlescent Paint

An interesting class of materials are metallic and pearlescent paints. They pose serious challenges to computer graphics since they have high frequencies in both angular and spatial domain, have a complex, pure stochastic spatial structure and angular dependent color shifts. Hybrid approaches that combine model and image-based representations have proven to faithfully reproduce metallic and pearlescent paint by compressing measured data. But until now the compression of the image based part is done with PCA based methods resulting in high amounts of data. One additional problem is the angular sampling of the measured data. Typical angular sampling densities of image based reflectance acquisition devices are very low compared to the solid angle, in which a metallic flake is visible, resulting in severe undersampling of the angular frequencies. We propose a simple method to measure these frequencies generated by the metallic flakes. Furthermore, we present a novel representation for metallic and pearlescent paint that allows resampling in angular domain corresponding to the flake properties and compression of measured image based paint data for high-quality paint rendering.