Method and system for object control

• US 7,725,288 B2
• Filed: 11/21/2006
• Issued: 05/25/2010
• Est. Priority Date: 11/28/2005
• Status: Expired due to Fees

• Current Assignee: Navisense
• Original Assignee: Navisense
• Inventors: Boillot, Marc Andre
• Primary Examiner(s): Wachsman, Hal D
• Assistant Examiner(s): HENSON, MISCHITA L
• Application Number:
  US11/562,404
• Publication Number:
  US 20070288194A1
• Time in Patent Office: 1,281 Days
• Field of Search: 702 39- 40, 702/72, 702/159
• US Class Current: 702/159
• CPC Class Codes: G06F 3/0304 Detection arrangements using opto-electronic means constructional details of pointing devices not related to the detection arrangement using opto-electronic means G06F3/033; optical digitisers G06F3/042
• CPC Class Codes: G06F 3/03547 Touch pads, in which fingers can move on a surface
• CPC Class Codes: G06F 3/043 using propagating acoustic waves

Abstract

A system (100) and method (400) for touchless object control is provided. The system can include a sensing unit (110) for capturing a first signal (677) reflected off a first object (151) at a first time and a second signal (679) reflected off the first object at a second time, a phase detector (116) for identifying a first phase difference (601) between the first signal and the second signal, and a processor (117) for updating an expected location of the first object using the first phase difference. A first object (143) can control a movement of a second object (124) using touchless control.

Claims

1. An input device for touchless object control, comprising:

a sensing unit comprising;

a transmitter for transmitting an ultrasonic signal; and

a receiver for capturing a first reflected signal off an first object at a first location and a second reflected signal off the object during movement to a second location;

a phase detector operatively coupled to the receiver for identifying a phase difference between the first reflected signal and the second reflected signal; and

a processor operatively coupled to the phase detector and the sensing unit for updating an expected location of the object using the phase difference, and controlling a user interface component in view of the expected location, wherein the processor

measures a first Time of Flight (TOF) between the transmitting of the ultrasonic signal and the capturing of the first reflected signal, and producing therefrom the expected location of the object at the first location,

measures a second Time of Flight (TOF) between the transmitting of the ultrasonic signal and the capturing of the second reflected signal, and producing therefrom an estimated location of the object at the second location, and

determines a relative displacement of the object by weighting a difference of the expected location and estimated location with the phase difference.

2. The input device of claim 1, wherein the estimated location is determined from the second time of flight measurement (TOF), and the relative displacement is evaluated within an error region determined from a differential time of flight measurement (dTOF).

3. The input device of claim 1, wherein the processor determines the relative displacement of the object by multiplying the phase difference with a subtraction of the estimated location and the expected location.

4. The input device of claim 1, wherein the input device is an ultrasonic sensor, an optical sensor, an imaging element, a camera element, or a laser element.

5. An input device for touch less object control, comprising:

a sensing unit comprising;

a transmitter for transmitting a signal; and

a receiver for receiving a first received signal reflected off an object and thereafter receiving a second received signal reflected off the object;

a phase detector operatively coupled to the receiver for identifying a phase difference between the second received signal and the first received signal; and

a processor operatively coupled to the phase detector and the sensing unit for

measuring a first Time of Flight (TOF) for the first received signal to produce an expected location of the object at a first location,

measuring a second Time of Flight (TOF) for the second signal to produce an estimated location of the object at a second location,

applying a weighted difference of the expected location and the estimated location to the phase difference to produce a relative displacement; and

updating the expected location of the object with the relative displacement in view of the expected location.

6. The input device of claim 5, wherein the processor identifies the estimated location of the object, and determines if the estimated location is within a region of relative displacement error of the expected location determined from differential time of flight (dTOF) measurements in view of the phase difference.

7. The input device of claim 5, wherein the processor determines the relative displacement of the object in view of the phase difference, the estimated location, and the expected location.

8. The input device of claim 5, wherein the input device tracks a touchless finger movement and controls an object in accordance with the finger movement.

9. The input device of claim 5, wherein the sensing unit includes a transmitter that generates a radiation pattern which is maximally wide in a generally vertical plane.

10. A method for touch less object control, the method comprising the steps of:

monitoring a movement of an object by measuring, with a processor, a first Time of Flight (TOF) to the object from a first reflected signal to produce an expected location of the object;

estimating, with said processor, a location of the object to produce an estimated location by measuring a second Time of Flight (TOF) to the object from a second reflected signal;

calculating, with a phase detector, a phase difference between the first reflected signal and the second reflected signal;

weighting, with said processor, a difference of the expected location and estimated location with the phase difference to produce a relative displacement of the object; and

updating, with said processor, the expected location of the object in view of the estimated location with the relative displacement.

11. The method of claim 10, further comprising:

controlling a second object in accordance with the relative displacement.

12. The method of claim 10, further comprising:

determining if the estimated location is within a region of the relative displacement of the expected location in view of the phase difference; and

,

if so, updating the expected location with a weighted difference of the estimated location and the relative displacement;

if not, updating the expected location with the relative displacement.

13. The method of claim 10, wherein calculating the relative displacement comprises:

capturing a first signal reflected off the object and a second signal reflected off the object; and

identifying the phase difference between the first signal and the second signal.

14. The method of claim 10, wherein calculating a relative displacement comprises:

capturing a first transmitted signal and a first received signal reflected off the object; and

identifying a first phase difference between the first transmitted signal and the first received signal.

15. The method of claim 10, further comprising:

updating the relative displacement in view of the expected location and the estimated location.

16. The method of claim 10, further comprising weighting a phase difference of the relative displacement with a reciprocal of a Time of Flight (TOF) curve.

17. The method of claim 16, further comprising performing a time weighted average of expected locations for updating the relative displacement.

18. The method of claim 16, further including mitigating phase discontinuities over time by selecting a phase difference with the shortest time distance to a time weighted average of the estimated locations.