Recognize pattern

Hello,guys I am trying to write a app in which I have to recognize user drawing just like these three here, so can you tell me how to do it under C#.
http://store.picbg.net/pubpic/56/45/...f2145a5645.png
http://store.picbg.net/pubpic/CB/5D/...06560bcb5d.png
http://store.picbg.net/pubpic/A7/C6/...465a6aa7c6.png

And I have one offtopic problem , so I hope you will answer it too. :)
I have a user control which is then initializen in winform , but I created a new winform I need to know when a user control checkbox == true , but when I try to get it , it's always false . I tryed even with public property but again without result.

Thanks in advance to everyone who will answer to my questions.

You should do some background reading before you begin. This is a complex topic.

http://en.wikipedia.org/wiki/Computer_vision

With regards to your checkbox problem please post some code so we can help you.

- Dan

Well this is what I build for two days :
http://store.picbg.net/pubpic/79/9B/...3ae178799b.png ,
but now I am trying to recognize these two:
http://store.picbg.net/pubpic/20/5A/...49337d205a.png

till now , without success . :)

Perhaps sharing your code?