Method and system for range measurement
A method ( 200 ) and system ( 220 ) for range detection is provided. The system can include a sensing unit ( 110 ) for detecting a location and movement of a first object ( 401 ), and a processor ( 107 ) for providing a measure of the movement. The processor can convert the measure to a coordinate signal for moving a second object ( 124 ) in accordance with a location and movement of the first object. The system can include a pulse shaper ( 109 ) for producing a pulse shaped signal ( 167 ) and a phase detector ( 101 ) for identifying a movement from a reflected signal ( 166 ). A portion of the pulse shaped signal can be a frequency modulated region ( 312 ), a constant frequency region ( 316 ), or a chirp region ( 324 ). In one arrangement, the pulse shaper can be a cascade of all-pass filters ( 515 ) for providing phase dispersion.
1. A sensing device for providing touchless control comprising:
a pulse shaper for producing a pulse shaped signal, the pulse shaped signal intended for reflecting off a first object to produce a reflected signal, wherein at least one portion of the pulse shaped signal is at least one among a frequency modulated region, constant frequency region, phase modulated region, and a chirp region;
a phase detector for receiving and identifying a relative phase of the reflected signal with respect to a previously received reflected signal, and
a processor operatively coupled to the pulse shaper for receiving the reflected signal, tracking a location and a movement of the first object from an estimated arrival time of the reflected signal and the relative phase, and providing control to a second object that is a user interface control in accordance with the location and the movement of the first object,
wherein the processor estimates the location of the first object from a frequency modulated region of the reflected signal, and a velocity of the first object from the relative phase from the constant frequency region of the reflected signal.
2. The sensing device of claim 1 , wherein the pulse shaper is a physical transducer element that emits the pulse shaped signal with a frequency modulation portion and an amplitude modulation portion.
3. The sensing device for claim 1 , wherein the pulse shaper includes at least one all-pass filter as a phase warping element for providing phase dispersion in the pulse shaped signal.
4. The method for claim 1 , wherein the pulse shaper concentrates an energy of the pulse signal within a narrow region of the pulsed shaped signal to produce a symmetric peak in the pulse shaped signal.
5. The method for claim 1 , wherein the pulse shaper transmits the pulsed shaped signal as a continuous transmission of a frequency modulated signal, a phase modulated signal, or an amplitude modulated signal.
6. An ultrasonic sensor device for short-range detection, comprising:
a pulse shaper for producing an ultrasonic chirp signal with an amplitude modulated region and a frequency modulated region;
at least one transmit sensor operatively coupled to the pulse shaper for transmitting the ultrasonic chirp signal, the ultrasonic chirp signal intended for reflecting off a finger to produce a reflected chirp signal;
at least one receive sensor for receiving the reflected chirp signal;
a phase detector for identifying a relative phase of the reflected chirp signal from the frequency modulated region with respect to a frequency modulated region of a previously received reflected signal, and
a processor coupled to the phase detector and the receive sensor for identifying a location of the finger from an arrival time of the amplitude modulated region of the reflected chirp signal and a movement of the finger from the relative phase of the frequency modulated region, and providing control to a user interface control in accordance with the location and the movement of the finger.
7. A method for touchless control, the method comprising the steps of:
shaping a pulse signal to produce a pulse shaped signal;
transmitting the pulse shaped signal, the pulse shaped signal reflecting off a first object 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;
estimating a location of the first object from a frequency modulated region of the reflected signal,
estimating a velocity of the first object from the relative phase from the constant frequency region of the reflected signal; and
providing control to a second object that is a user interface control in accordance with the location and the movement of the first object,
wherein the shaping uses a combination of amplitude modulation, frequency modulation, and phase modulation.