Traditional cartoons have been widely used in entertainment

education

and advertisement. Thus

a large amount of cartoon data is available. In this paper

we propose a new technique for capturing the motion of a character in an existing cartoon sequence. This technique tracks the contours of the cartoon character in the sequence

and key frames are used to guide the tracking. We model contour tracking as a space-time optimization problem in which an energy function including both temporal and spatial constraints is defined. First

the user labels the contours of the character on the key frames. Then

the contours on the intermediate frames are tracked by minimizing the energy function. The user may need to interactively adjust the tracking result and restart the optimization process to refine the result. Finally

an edge snapping algorithm is applied to make the tracking result more precise. Experiments show that our technique works effectively.