15. A processor-implemented method for modeling a pose of a hand of a user, comprising: obtaining depth pixels of the hand in one or more frames; processing the depth pixels of the one or more frames to identify articulated portions of the hand; accessing a model of the articulated portions of the hand, the articulated portions of the hand of the model comprising a palm and fingers, including finger segments; matching the articulated portions of the hand of the model to the identified articulated portions of the hand of the depth pixels of the one or more frames, to provide an initial match; evaluate an extent to which distance constraints are violated in the initial match by at least one of the fingers, the distance constraints comprise constraints on distances between finger segments of the at least one of the fingers; deciding to enforce collision constraints; in response to the deciding to enforce collision constraints, evaluating an extent to which the collisions constraints are violated in the initial match by at least two adjacent finger segments of the model; and adjusting the model: (a) in an attempt to satisfy the collision constraints, based on the extent to which the collision constraints are violated by the at least two adjacent finger segments of the model, by decreasing widths of the at least two adjacent finger segments of the model and (b) in an attempt to satisfy the distance constraints, based on the extent to which the distance constraints are violated by the at least one of the fingers.
15. A processor-implemented method for modeling a pose of a hand of a user, comprising: obtaining depth pixels of the hand in one or more frames; processing the depth pixels of the one or more frames to identify articulated portions of the hand; accessing a model of the articulated portions of the hand, the articulated portions of the hand of the model comprising a palm and fingers, including finger segments; matching the articulated portions of the hand of the model to the identified articulated portions of the hand of the depth pixels of the one or more frames, to provide an initial match; evaluate an extent to which distance constraints are violated in the initial match by at least one of the fingers, the distance constraints comprise constraints on distances between finger segments of the at least one of the fingers; deciding to enforce collision constraints; in response to the deciding to enforce collision constraints, evaluating an extent to which the collisions constraints are violated in the initial match by at least two adjacent finger segments of the model; and adjusting the model: (a) in an attempt to satisfy the collision constraints, based on the extent to which the collision constraints are violated by the at least two adjacent finger segments of the model, by decreasing widths of the at least two adjacent finger segments of the model and (b) in an attempt to satisfy the distance constraints, based on the extent to which the distance constraints are violated by the at least one of the fingers. 16. The processor-implemented method of claim 15 , wherein: the deciding to enforce collision constraints comprises determining that the at least two adjacent finger segments of the model are in a specified relative position.