 Applications
Using Photometric Stereo (PS)
Computer graphics and oil paintings
The term 'painterly rendering' describes a range of techniques that
are used to process real images to give them the appearance of paintings.
It has been exploited in commercial applications (e.g. Photoshop).
Although successful these techniques do not model the topography of
the painted surface. This is an important quality of many paintings,
particularly of impressionists. In this work we use photometric
stereo to recover the topography of brushstrokes and signal processing techniques
to analyse them.
We believe the result has a tactile quality that makes it more appealing
to the viewer.
   
Test samples of paper and brushstrokes used for modelling
A method for recovering and quantifying the topography of oil paintings
is described. Photometric stereo (PMS) is used to estimate the shape
of the painted surface. The statistics of samples painted with different
brush strokes and sizes are measured. The analysis was used to improve
an existing algorithm for non-photorealistic rendering. We found PS
to be an effective method of surface recovery. Different stroke styles
were found to have distinctive point statistics. We conclude that PS
is an effective way to recover the topography of oil paintings; that
the point statistics distinguish the types of brush stroke in a concise
and meaningful way; that the power spectrum is a useful method to describe
the texture surface; and this information can be used to improve the
performance of a painterly rendering algorithm.
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