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This recap discusses the first attempts of the Artistic Rendering Project Beta by Jeremy Shopf, focusing on innovations in shade acquisition and how depth maps can be derived from luminance. The project aims to merge shape and shading using arbitrary Bidirectional Reflectance Distribution Functions (BRDFs), yielding impressive results on the first try. Key concepts include using edge-preserving blur, simulating human visual systems, and fitting functions to pixel data. Insights on non-intuitive shading values in painterly rendering are also covered.
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Artistic Rendering ProjectBeta Release Jeremy Shopf 11/21/06
Recap • Combine shape from shading with shading acquistion • Inspired by “Image-based Material Editing” • Get depth map from luminance • Apply arbitrary BRDFs to depth map • Awesome results
First Attempt • Get shape • Convert RGB to luminance • Use edge-preserving blur • Compress to simulate human visual system • Resulting values are used as depth • Calculate gradient • Get shading from shape • Assume isotropic surface shading • Estimate light direction in painting • Calculate angle of each pixel normal with light • For each pixel of a given angle, average all colors • Not good • Try and fit a function to it using least squares • Data too random to get anything remotely accurate
Second Attempt • Find pixel with the greatest luminance • This must be the color the material exhibits when its normal is approximately the lighting direction • Find pixel with the lowest luminance • Weight by distance from pixel with greatest luminance • Define shading function as all pixels between the brightest and darkest pixels N dot L 0.0 1.0
Result.. N dot L 0.0 1.0
Improvements • What about when the artist chooses non-intuitive shading values • Pick greatest luminance as start, and closest pixel outside of object as end • Apply to painterly rendering!
