Automatic document reading system for technical drawings

#Many paper-based technical drawings from the past are still valuable for design, manufacturing and maintenance support. Unfortunately, managing these paper-based technical drawings, which are typically kept in paper file archives, is expensive and labor-intensive.

#An electronic archival system capable of accessing and managing drawings for immediate electronic retrieval and/or viewing is desireable. An obstacle to creating such a system is that the textual descriptions in the paper-based drawings must be extracted, recognized, and stored electronically. However, manual input of textual descriptions is generally unacceptable because it presents a slow and fallible process.

#Several form-reading systems have been proposed or developed for the processing of generic forms. Unfortunately, the processing of technical drawings faces more difficult challenges in that technical drawings are scanned in large image format, and the document data required for processing is often quite large; noise and artifacts due to document aging degrade the quality of scanned images, and the cost for skilled human intervention is significantly high; and technical drawings have a variety of form layouts and context styles, and the information to be read varies from one drawing to another. In order to achieve desirable performance in speed and accuracy, an automated system for electronic archival of paper-based technical drawings is needed.

#The present disclosure teaches electronic archival of paper-based technical drawings in accordance with the following exemplary figures, in which:

#FIG. 1 shows a block diagram of a system for electronic archival of paper-based technical drawings according to an illustrative embodiment of the present disclosure;

#FIG. 2 shows a partial-schematic flow diagram for a method of using the system of FIG. 1;

#The reading of technical drawings is a complex task for automated document processing. In the present disclosure, a system is presented for reading textual descriptions from technical drawings that provides capabilities for converting paper-based drawing documents into an electronic archival database. The system includes the four major processing elements of form learning, form localization, optical character recognition (“OCR”), and result verification. The algorithms for each element are dedicated to solving the practical problems involved with reading technical drawing documents. Among them, form localization and OCR are key processes that realize great benefits from automation. Results have proven the feasibility and efficiency of the presently disclosed approaches.

#In the present disclosure, an automated reading system is especially dedicated to technical drawings. The designed system for electronic archival of paper-based technical drawings reduces the human labor involved in entering information from paper-based documents. To make a system work practically, reading of textual descriptions is facilitated by bounding with geometric or rectangular boxes located in the form area and the graphic area. These boxes contain the drawing identification number, revision history (e.g., date, author, version number) and parts interconnection; which are the most important information regions in this exemplary embodiment. Reading of annotated text outside of bounding boxes is not important because such text is typically mixed with graphics and does not reveal information that is important for building an electronic archival system.

#FIG. 1 shows a block diagram of a system 100 for electronic archival of paper-based technical drawings according to an illustrative embodiment of the present disclosure. The system 100 includes at least one processor or central processing unit (“CPU”) 102 in signal communication with a system bus 104. A read only memory (“ROM”) 106, a random access memory (“RAM”) 108, a display adapter 110, an I/O adapter 112, and a user interface adapter 114 are also in signal communication with the system bus 104.