From 1990 to 1995 the Hamburg AI-Laboratory has been committed to research on three successive "drawing interpretation" projects:
 

WIZ Project

Duration: 07/90 - 03/92

The WIZ project was part of an European cooperation project (ESPRIT 2001), where the AI-Laboratory served as a subcontractor of AEG Electrocom (Konstanz). The goal of WIZ was to realize a knowledge-based support for the conversion of paper-based drawings into actual CAD representations. As the vectorization was realized by a commercial tool, the WIZ prototype focussed on techniques to recognize higher-level structures in the drawing by exploiting domain knowledge. The basic processing mechanism is inspired by a blackboard metaphor, which realizes a bottum-up recognition of domain-specific objects, like dimension sets in engineering drawings.

For simple axle-like drawings a post-processing step can be invoked. This step makes use of the recognized contour lines and dimension sets to check the dimensioning of drawing according to completeness, correctness, and redundancy. In case of success the drawing is redrawn according to its explicit dimensioning, and a 3-D CAD model is generated.

Development of an "Adaptable Drawing Interpretation Kernel" (ADIK)

Duration: 04/92 - 09/93

To make drawing interpretation available for other domains (like electronic circuits, geographic maps, architectural plans, etc.) an "adaptable drawing interpretation kernel" (ADIK) was developed as a prototype. The key elements of this approach are a declarative specification language for geometry and a specialized inference engine that recognizes the described objects very efficiently. This prototype has been tested on various kinds of drawings.

Domain-specific objects and the relations inbetween are recognized as the result of the interpretation. This network of objects and relations can be visualized by a graph-viewing utility, which is part of ADIK. For example, the picture below shows a "diode-bridge" object as an aggregation of four "diode" objects and four electric connections represented as "node" objects.

InterDok Project

InterDok is a cooperation project with Technical University of Hamburg-Harburg, Körber AG, Daimler Benz Aerospace-Airbus, ASCAD GmbH Nord and SerCon GmbH. The aim of the project is to further develop the ADIK prototype into a practically applicable tool for various "drawing interpretation" purposes. The concrete project goals are:

• Conversion of old pure line-based CAD-data of electric sheets into a new object-oriented design tool for electric sheets.
• Conversion of "flat" mechanical engineering drawings (generated by a vectorization tool or extracted from an old line-based CAD system) into a representation that is capapable of distinguishing between contour lines, dimensioning information and additional annotations.
• Automatic evaluation of a drawing's text area in order to derive index information to support a semantics-oriented database storage.