An Interactive CAD-Based Vision System

We report a preliminary implementation of an interactive system that enables a draftsperson using only the standard features of a commercial CAD package (AutoCAD) to construct a model-based vision program. Some of the information needed by the model-based vision program is computed automatically from the drawing, but the draftsperson can also provides guidance on expected image-feature types by drawing the corresponding parts of the model on named CAD-layers and can indicate the visibility of arbitrary parts, such as expected shadow lines, by connecting them to modelled parts with invisible construction lines. Our system, running on a workstation, converts small drawings to computer vision programs in approximately 5 seconds, though an additional 35 seconds is used on networking, windowing, and software initialisation.We argue that interactive CAD-based vision compilers are more useful than contemporary batch-mode CAD-based vision compilers and conclude that the emergence of the international standard STEP will support the development of more competent CAD-based vision compilers of all kinds.