Computerising 2D Animation and the Cleanup Power of Snakes

Traditional 2D animation remains largely a hand drawn process. Computer-assisted animation systems do exists. Unfortunately the overheads these systems incur have prevented them from being introduced into the traditional studio. One such problem area involves the transferral of the animator's line drawings into the computer system. The systems, which are presently available, require the images to be over-cleaned prior to scanning. The resulting raster images are of unacceptable quality. Therefore the question this thesis examines is; given a sketchy raster image is it possible to extract a cleaned-up vector image? Current solutions fail to extract the true line from the sketch because they possess no knowledge of the problem area. However, snakes use prior knowledge about the nature of sketchy images to deter-mine the correct line from several possibilities. As a snake is an energy minimising spline, the result is in vector format. Therefore in extracting the clean line from the sketch the conversion from raster to vector is also achieved. This technique makes snakes less prone to errors than the current algorithms. In reducing the errors, the overhead produced when transferring the drawings from paper to computer is also reduced