Reading 9 : Introduction to Gesture Recognition

Citation:
Chapter 2 : Gesture Recognition by Features - Tracy Hammond

Summary:
This chapter goes into the specifics behind each of Rubine's features, and presents examples of gestures and their corresponding feature set, and also a brief overview of Long's features. An important aspect of gesture recognition is that path of a gesture must be the same for recognition to work.

Discussion:
In this paper, a stroke is defined as a set of <x,y,t> points.

Features 1 and 2: The cosine and sine of starting angle (taken between the first and third point) to avoid getting the same point due to high sampling rate). We require both the sine and cosine as only together, with their sines, can we get an exact idea of the direction, since the angle is not a continuous feature at axe boundaries)

Features 3 and 4: Length and Angle of the bounding box

Feature 5 : Start and Endpoint distance

Feature 6 and 7: Cosine and sine of angle between start point and end point

Feature 8 : Total Stroke Length

Feature 9: Total Rotation

Feature 10: Total Absolute Rotation

Feature 11 : Sharpness

Feature 12 : Maximum speed

Feature 13: Time taken

Long's features are discussed in the next paper.