12. A system for recognizing a gesture performed by a user comprising: an image capture device that acquires a sequence of input images of a specific user; and a processing device that recognizes a gesture of the specific user from the sequence of input images based on a gesture model and geometrical features extracted from a hand trajectory of the user, the processing device further detects abrupt changes of motion parameters of at least one object in each frame of the sequence of input images as candidate starting points of the gesture, tracks the candidate starting points though the sequence of images, matches the candidate starting points of the sequence of input images to at least one first gesture model, detects state transition points of the at least one first matched gesture model, extracts geometrical features of a hand trajectory from the sequence of input images based on relative locations of the detected state transition points of the at least one first matched gesture model and a starting point of the gesture, computes a gesture model matching score for each frame of the sequence of input images for the candidate starting points for each gesture class using the at least one first gesture model and extracted geometrical features, prunes the at least one first gesture model based on the gesture model matching score of at least one frame of the sequence of input images and classifies the gesture as the gesture class with the highest match score.
19. The system as in claim 12 , wherein the processing device is further configured for adapting the at least one first gesture model and geometrical feature distribution for the specific user based on gestures performed by the specific user.