14. One or more processor readable storage devices according to claim 9 , wherein: determining whether the modifier for the first mid-air gesture is present includes determining whether the human target issues a speech modifier.
9. One or more processor readable storage devices having processor readable code embodied on the one or more processor readable storage devices, the processor readable code for programming one or more processors to perform a method comprising: receiving depth information of a capture area including a human target; creating a skeletal model for mapping movement of the human target over time; detecting a gesture modifier from the human target that indicates a gesture period by determining that the human target has raised a hand to a position satisfying a gesture modifier filter parameter; determining a start of the gesture period based on a time at which the human target raises the hand; in response to detecting the gesture modifier, determining from the skeletal mapping whether movement of the human target during the gesture period satisfies one or more filters for a first mid-air gesture; if the movement of the human target during the gesture period satisfies the one or more filters, performing a first user-interface action corresponding to the first mid-air gesture; determining that the human target has lowered their hand from the position satisfying the gesture modifier filter parameter; and determining an end of the gesture period based on a time at which the human target lowers the hand.