Stylization-based ray prioritization for guaranteed frame rates

This paper presents a new method to control graceful scene degradation
in complex ray-based rendering environments. It proposes
to constrain the image sampling density with object features, which
are known to support the comprehension of the three-dimensional
shape. The presented method uses Non-Photorealistic Rendering
(NPR) techniques to extract features such as silhouettes, suggestive
contours, suggestive highlights, ridges and valleys. To map different
feature types to sampling densities, we also present an evaluation
of the features impact on the resulting image quality. To reconstruct
the image from sparse sampling data, we use linear interpolation
on an adaptively aligned fractal pattern. With this technique,
we are able to present an algorithm that guarantees a desired minimal
frame rate without much loss of image quality. Our scheduling
algorithm maximizes the use of each given time slice by rendering
features in order of their corresponding importance values until a
time constraint is reached. We demonstrate how our method can
be used to boost and guarantee the rendering time in complex raybased
environments consisting of geometric as well as volumetric
data.