I'm not convinced that a correct game AI problem has even been stated. This smacks too much of "I want the AI to figure everything out for me."

You have to reduce the problem: Image -> smaller data (aka feature vectors) The idea is to convert the image into a different smaller representation - i.e generating an outline of the Y by running an edge detection algorithm (convolution) over it and say generating a series of connected lines. The recognition is done on the feature vectors not the original image. In speech you have: Sound -> phonemes which is similar to the above.

Hi, I haven't read through every post, so sorry if it's been mentioned before, but I recommend you consider the book 'AI Techniques for Game Programming' by Mat Buckland and/or see his website. Nice, and easy to digest, information on neural networks and such.

I suspect you could solve this problem using image pattern and/or feature matching techniques. But Im not sure it worth the trouble unless this will REALLY make a difference in game play. I use some of these techniques for some of my contract gigs and its fairly complicated software. Here's what I consider to be the state of the art feature matching software: http://www.cs.ubc.ca/~lowe/keypoints/

I started to do gesture recognition for one of my games. It actually worked pretty well. It basically goes like this: Manually create a list of points that represents what the pattern should look like - I'll call this the test list. Store the mouse position at some interval (say, once per cycle) in a list of points - I'll call this the point list. Loop through each point in the test list and calculate the distance between it and it's corresponding point in the point list. Add the distances together to find the "offness". The only somewhat tricky part is matching the points in the test list to the corresponding point in the point list. Just visualize cutting the point list into n equal portions where n = the number of points in the test list and then taking the point at each "cut". There's probably a better way to explain that mathematically, but math really isn't my thing