Computer vision for recording shapes of parts of the human body

This paper deals specifically with recording the shapes of teeth but the same techniques could apply generally, say to feet requiring bespoke, surgical footwear. Machine tools exist already for reproducing shapes by cutting in irregular paths providing that the coordinates are known for each path; this leads to all sorts of applications such as the production of shoe lasts and the generation of patterns for castings. Currently the dental profession uses plaster casts to store and transfer information about teeth with the attendant costs and delays. With a new available computer dental network, using artificial vision and wire diagrams has obvious attractions. Once a diagram has been obtained then it is possible to rotate it and view it from any angle as well as to look at cross sections and take exact measurements from it. The principle of operation is as follows. An object on which a light shines is rotated. A digital camera captures the series of the profiles so formed. Under program control these profiles are then used to build up a wire diagram of the object. There are problems such as lens distortion and fuzzy lines as well as the problem of geometrical perspective and the necessity of oblique positioning of the camera. The paper describes the current state of the work and how the various problems are being tackled