1. A method, comprising: detecting an execution of a gesture by a user's hand by tracking movements of said hand in the vicinity of a device within a limited sensing space defined by a plurality of ultrasonic transducers; identifying at least one object displayed by the device from the tracked movements; generating data that is descriptive of at least of a shape of the user's hand in three dimensional space when executing the gesture; capturing an image of fingertips of the user's hand; determining a number of fingertips from the captured image, a spacing between each fingertip and an angular orientation of each fingertip relative to one another; determining whether to begin a gesture recognition process, wherein determining whether to begin the recognition process comprises detecting a predetermined pattern of fingertip movement, a velocity of the fingertip movement or a size of the fingertip, the number, spacing and angular orientation of the fingertips corresponding to the predetermined fingertip pattern, and if the recognition process is begun; comparing a current image of the fingertips with at least one prior image of the fingertips to determine a fingertip trace corresponding to the executed gesture; displaying a pointer in at least one position corresponding to the executed gesture; and determining at least one command for said at least one object displayed by the device based at least in part on the data and the executed gesture.