# 8 $N: A Multistroke Recognizer

# 8 $N: A Multistroke Recognizer

Comments:

Youyou wang

Summary:

$N is an extension of $1 from the same author. $ N algorithm solves many limitations of $1. Below are some new functions of $N:

(1)   Being able to recognize multistroke gestures, also, this algorithm automatically generates all possible combination of those strokes, which is very convenient for users.

(2)   $N can distinct gestures that only different on their orientations. This is done by using bounded rotation invariance instead of full rotation invariance.

(3)   Being able to distinguish 1D gestures like lines.  $N firstly differentiates 1D from 2D by computing their ratio of sides of their oriented bounding box. Obviously, this ratio of 1D gesture is lower than 2D’s.

(4)   $N also use start angles to decrease the number of comparisons. In addition, it also speeds up the algorithm by comparing only with templates with the same number of strokes.

Discussion:

$N is still very simple for implementing. Even though it announce can deal with multistroke, actually it still deal with them as one stroke gestures.  That is why it has difficulty to distinguish “=” with z. Also, if the number of strokes increased, the speed of this algorithm will be decreased. I am interested about combine some features of Protractor with $N.