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

Source Image

First Attempt est kaput

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

0.0 1.0N dot L

Result..

0.0 1.0N dot L

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!