Graphical input through machine recognition of sketches

by

Christopher F. Herot

Summary

1976, was the year of the United States bicentennial. It was also the year that Apple Computer was formed. So one might ask why we are reading a paper from 1976? Our readings so far have lead us to believe - wrongly - that sketch recognition went from Sutherland's SketchPad straight to Rubine's gesture recognizer. This paper shatters that belief.

The paper opens up by noting that the research done was motivated by the "desire to involve the computer in the early stages of the design process, where the feedback generated by the machine can be most useful." If this sounds familiar it is because ever paper on sketch recognition uses a very similar motivation to frame their work. Herot states that the machine observes the sketches of the subject while they are being created, and this information could be used to make inferences about the user's attitude about the sketch. He also presents the question could a machine make useful interpretations of sketches without knowing the domain in which the sketches are made.

Herot also notes - which I wrongly assumed Sezgin discovered - that the speed of the stroke descends at the corners. Herot even plots this onto a graph noticing the minimum of speeds as the corners. He also notes that the recognition of the system is influenced by the drawing styles of those who've created it. During demonstrations the system would work well for some, but not for others. The paper also discusses latching - the connecting of near miss edges - and overtracing. The paper states that context should be used at the lowest levels of recognition, and that the program must be tuned to the user.

Herot states that the user should not be removed from the recognition process, noting that a promising approach involves "the user to make decisions of which the machine is not
capable, but still affording the unobtrusive input method of sketching."

Discussion

I didn't realize that Negroponte was involved in sketch recognition until I looked through the works cited section. It is weird to see the same language used to describe the problem in 1976 still used in 2007. The metric bentness and the use of speed seem to be very similar to the metrics that Sezgin used. More work still needs to be done with latching and overtracing.

Citation

Herot, C. F. 1976. Graphical input through machine recognition of sketches. In Proceedings of the 3rd Annual Conference on Computer Graphics and interactive Techniques (Philadelphia, Pennsylvania, July 14 - 16, 1976). SIGGRAPH '76. ACM Press, New York, NY, 97-102. DOI= http://doi.acm.org/10.1145/563274.563294