Deriving CAD data from manufactured parts

Presents a system which automatically generates two-dimensional CAD data from sheet-metal templates by use of image analysis techniques. The emphasis lies on techniques for interpreting contour primitives with high accuracy. This is done by a rule-based evaluation of a B-Spline approximation of the contour. In the aerospace industries it is a problem to derive CAD data from sheet-metal templates for which no drawings are available. Usually, these templates are digitized manually by use of a graphics tablet in close interaction with a CAD system. The new `ConturCAD´ system reduces this time-consuming and costly process and, moreover, it can be used for quality control purposes of custom-made parts. Concerning this application, a quality control system will be worked out that uses CAD data derived by our system and CAD data from the design process for quality verification