METHOD AND APPARATUS FOR THE OPTICAL DETERMINATION OF SURFACE PROFILES

A method and apparatus for providing information as to the cross-sectional shape or profile of a body is disclosed in which a known datum in the form of a bar 50 having a cross-shaped cross-section is detected by a camera 14. A body is then detected by the camera 14 to provide preliminary information as to the shape or profile of the body and the preliminary information is transformed in accordance with a variation of the detected datum from the known datum to provide a better indication of the true cross-sectional shape or profile of the body. The known datum 50 enables at least three non-colinear reference locations to be defined and calibration parameters are determined from the reference locations so that exact reference locations can be determined.