We are happy to annouce that the QuickDiagram system is now publicly accessible as an open source project hosted at http://code.google.com/p/quickdiagram/. We hope all researchers and developers interested in this project can help improve it in any aspect, including the stroke pre-processing algorithms, graphic recognition algorithms, diagram understanding algorithms for more domains, and the general UI. Suggestions for new functions, or even bug reports or bug fixing suggestions will also be appreciated.

QuickDiagram was initially develoeped in 2003-2004 by a team lead by Dr. LIU Wenyin at the City University of Hong Kong for quick input and understanding of circuit diagrams by sketching. With a user sketching a (complete or partial) component/symbol or wire (connecting two symbols) of the diagram, the system can recognize and beautify it immediately. After the entire diagram is complete, certain understandings can be obtained. The system has a symbol database with more than 600 circuit devices/symbols. Three steps of stroke processing, filtration, and on-line recognition are used to recognize a circuit symbol even before it is completely sketched. The following two methods are used to interpret the recognized diagram: 1) circuit simulation on resistive circuits based on the Nodal Analysis, and 2) generation of PSpice codes from the recognized diagrams. Experiments on a few sketched circuit diagrams show that the results are robust and accurate for both recognition and understanding. This system is still in its preliminary stage and we call for open source contributors to collaboratively and gradually make the system mature for practical usage. Anyone who is interested in downloading and contributing the project is welcome to contact with the project leader Dr. LIU Wenyin at This email address is being protected from spambots. You need JavaScript enabled to view it. . Thanks for your potential interest and contribution.