Oriented Particle Spray: Probabilistic Contour Tracing with Directional Information

Contour following is a standard activity in rotoscoping in the digital post production domain. An artist might need to cut out or edit an object separately from its background and it is left to the artist to manually create the cut out. Techniques for automatically tracing the edges of the object exist, but these operate with heavy manual intervention. The most recent technique called JetStream is a considerable advance on manual or semi-automatic tracing, but suffers from a lack of direction information in the image. This paper considers the incorporation of this information and so reworks the principle of density propagation for contour following. The approach is more robust than previous methods although inevitably needs user intervention to incorporate image semantics.