How can I use SVM functions to recognize numbers?

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Hi I want to use SVM methods to recognize digit images. I think at first I must write some functions and apply them into some images(training set) and then apply them in rest of my image database(testing set) and finally input both of them to SVM function as training and testing sets respectively.

Am I right? Is this all of the story?

Is there any examples to help me? I don't know how can I use SVM in OpenCV!