Reading 10

Visual Similarity of Pen Gestures

Citation:

Long Jr, A. Chris, et al. "Visual similarity of pen gestures." Proceedings of the SIGCHI conference on Human Factors in Computing Systems. ACM, 2000.

Publication Link: http://dl.acm.org/citation.cfm?id=332458

Summary:

Multidimensional scaling is used for reducing the dimensionality so that the matrices can visualized better for similarity. Regression analysis is done to find out which dimension represents what. 22 features were used to identify gestures, 11 of which were inherited from Rubine. 

This paper suggests that aspect is much more powerful than length and width of bounding box diagonal. The impact it creates is much higher. Also, the length and arc of shape have much lower impact. The log of aspect creates more sense than log because the values are normalized and easy to visualize for differences. 

Density metric is used for differentiating between coloring and scribbling. The curviness is measured with a threshold angle of 19 degree, which is got by summing small difference in angles.

Discussion:

I found the observation that log creates a better perception very intuitive. It certainly eases the comparison between two similar looking figures. Also, the selection of 19 degrees for the value f curviness could be explained a little bit more.