9. One or more computer-readable storage devices having computer-executable instructions, which when executed perform operations comprising: processing sensed depth data for a plurality of frames that include hand movement, wherein processing the sensed depth data comprises: segmenting the depth data to isolate a hand represented in the frames of depth data; determining that a principal direction of the hand is not pointing in a predefined direction in an image plane; based on the determining, rotating the hand such that palm of the hand is substantially parallel to an image plane and such that the principal direction of the hand is pointing toward the predefined direction in the image plane; performing normalization on the rotated hand to provide normalized hand data to compensate for scale and a relative hand size of the hand; and extracting feature values corresponding to the normalized hand data; and recognizing the hand movement as a hand gesture based upon the feature values provided to a classifier.
9. One or more computer-readable storage devices having computer-executable instructions, which when executed perform operations comprising: processing sensed depth data for a plurality of frames that include hand movement, wherein processing the sensed depth data comprises: segmenting the depth data to isolate a hand represented in the frames of depth data; determining that a principal direction of the hand is not pointing in a predefined direction in an image plane; based on the determining, rotating the hand such that palm of the hand is substantially parallel to an image plane and such that the principal direction of the hand is pointing toward the predefined direction in the image plane; performing normalization on the rotated hand to provide normalized hand data to compensate for scale and a relative hand size of the hand; and extracting feature values corresponding to the normalized hand data; and recognizing the hand movement as a hand gesture based upon the feature values provided to a classifier. 11. The one or more computer-readable storage devices of claim 9 having further computer-executable instructions, which when executed perform operations comprising training the classifier with feature values extracted from frames of depth data that are associated with intended hand gestures, and wherein recognizing the hand movement as a hand gesture based upon the feature values comprises inputting a feature vector representative of the feature values to the classifier.