Tracking holes: using animation to visualize absent features

Sequences of scenes containing interacting objects require careful analysis and presentation to assist viewers in understanding object motion. This paper discusses an approach for detecting and visualizing absent features in a series of images containing moving objects. A minimum area invariant is introduced to classify objects by their states. The availability of such state information permits simplified visual models of the behaviour. We compare models based on static visualization of state information with computer animations developed specifically for the application