Reading Assignment: What!?! No Rubine Features?: Using Geometric-Based Features to Produce Normalized Confidence Values for Sketch Recognition

Reference Information
Title: "What!?! No Rubine Features?: Using Geometric-Based Features to Produce Normalized Confidence Values for Sketch Recognition
Authors: Brandon Paulson, Panjaj Rajan, Pedro Davalos, Ricardo Gutierrez-Osuna, Tracy Hammond
Citation: "What!?! No Rubine Features?: Using Geometric-Based Features to Produce Normalized Confidence Values for Sketch Recognition", Brandon Paulson, Pankaj Rajan, Pedro Davalos, Ricardo Gutierrez-Osuna, Tracy Hammond.

Summary
This paper discussed a hybrid approach for sketch recognition that combines gesture-based recognition methods and geometric-based recognition methods. Gesture-based recognition uses the stroke properties of the gesture to classify gestures into a particular gesture class. Geometric-based recognition uses the geometric properties of the sketch itself to classify it as a geometric shape. The idea of a hybrid approach was to use the best aspects of each type of recognition to create an improved recognizer for natural sketches with normalized confidence values.

A set of 44 features were used, with 13 gesture-based features (Rubine's) and 31 geometric-based features. Feature subset selection was performed with this set of features in order to determine those features that were the most important for accurate recognition. It was determined that the geometric-based features were selected as being more signification for the given data set than the gesture-based features.

Thoughts
We haven't discussed geometric-based recognition much yet in class, so this paper provided a great, general explanation of what it is. The idea to combine the two sketch recognition methods, gesture-based and geometric-based, into a hybrid recognition system seems like it could be very advantageous due to the combination of the different kinds of techniques. I found it particularly interesting that the feature selection resulted in demonstrating that the geometric features were much more significant than most of the gesture features, even though the Rubine features that were used as the gesture features are a common method for sketch recognition. It would be interesting to determine exactly why the geometric features were chosen as being more significant and if it may be based on the particular data that was used to test the features.

I also liked that this paper built on work that we have seen in previous reading assignments, such as the papers describing the Rubine and Long features. It provided a means for showing ways that the topics discussed in the previous papers have influenced future research.