Patent ID: 7724355
Filing Date: 2010-05-25
Classification: G01S,G06F

Abstract:
1. A method for short range detection using ultrasonic sensing, comprising: shaping a pulse signal to produce a pulse shaped signal; transmitting the pulse shaped signal, the pulse shaped signal reflecting off a finger to produce a reflected signal; receiving the reflected signal; identifying a relative phase of the reflected signal with respect to a previously received reflected signal; tracking a location and a movement of the finger from an arrival time of the reflected signal and the relative phase; saving most recent echoes to a history, and selectively discarding echoes less recently saved in the history based on a similarity measure between echoes in the history; and providing touchless control to a user interface control in accordance with the location and the movement of the finger, wherein the shaping uses a combination of amplitude modulation, frequency modulation, and phase modulation.