Systems and methods for optical sensor navigation

Patent metadata

Field	Value
Publication number	US-10670402-B2
Application number	US-201414530494-A
Country	US
Kind code	B2
Filing date	Oct 31, 2014
Priority date	Nov 1, 2013
Publication date	Jun 2, 2020
Grant date	Jun 2, 2020

Abstract

Systems and methods are disclosed for determining a navigational constraint for a portable device using an optical sensor. The navigational constraint may be used to supplement other navigational solutions or may be used independently. The optical sensor may capture a plurality of samples to be processed to determine the constraint. Determining the constraint may include any or all of determining a context for usage, distinguishing usage modes, estimating an orientation of the portable device, determining an absolute and/or relative elevation, determining a direction of motion and determining a speed of the portable device from the samples.

First claim

What is claimed is:

1. A method for navigating with a portable device associated with a user comprising:
processing a sequence of samples from an optical sensor of the portable device;
determining a navigational constraint for the portable device based at least in part on the processed samples, wherein processing the sequence of samples from the optical sensor comprises performing an optical flow analysis, wherein the portable device and the optical sensor may assume varying orientations with respect to the user depending at least in part on how the portable device is being used, and wherein the navigational constraint comprises at least one of:
a) a context for the portable device, wherein the context comprises at least one of:
i) the context corresponding to fidgeting motion;
ii) the context corresponding to substantially constant altitude movement; and
iii) the context corresponding to varying altitude movement; and

b) an estimated speed of the portable device; and

providing a navigation solution for the portable device based at least in part on the determined navigational constraint.

2. The method of claim 1 , wherein determining the navigational constraint comprises determining the context for the portable device.

3. The method of claim 1 , wherein performing the optical flow analysis comprises aggregating estimations of pixel translations between the samples.

4. The method of claim 1 , further comprising estimating a device angle with respect to a direction of motion.

5. The method of claim 4 , further comprising determining the context of the portable device by assessing variance in a plurality of estimated device angles.

6. The method of claim 1 , further comprising determining the context of the portable device by calculating an optical flow ratio.

7. The method of claim 2 , further comprising determining the context of the portable device by comparing similarity between samples.

8. The method of claim 4 , further comprising determining a usage of the portable device based at least in part on the estimated device angle.

9. The method of claim 8 , wherein determining the usage of the portable device is also based at least in part on an orientation determination using an inertial sensor.

10. The method of claim 2 , further comprising determining the context of the portable device by identifying a feature in the samples.

11. The method of claim 2 , further comprising determining an additional context that corresponds to being static.

12. The method of claim 2 , further comprising determining the context corresponds to fidgeting motion.

13. The method of claim 2 , further comprising determining the context corresponds to substantially constant altitude movement.

14. The method of claim 2 , further comprising determining the context corresponds to varying altitude movement.

15. The method of claim 14 , wherein determining the navigational constraint further comprises determining a relative change in elevation from the samples.

16. The method of claim 14 , further comprising identifying an external indication of altitude in at least one of the samples.

17. The method of claim 1 , wherein determining the navigational constraint comprises estimating the speed of the portable device.

18. The method of claim 17 , wherein estimating the speed of the portable device utilizes the optical flow.

19. The method of claim 17 , wherein estimating the speed includes deriving a scale factor from a distance to a feature identified in the samples.

20. The method of claim 19 , wherein the distance to the feature is determined using an inclination angle of the portable device.

21. The method of claim 19 , wherein the distance to the feature is determined from a ratio of periodic displacement of the portable device to corresponding displacement of a feature identified in the samples.

22. The method of claim 1 , wherein the portable device further comprises inertial sensors, wherein the method further comprises an inertial navigation routine and wherein the navigational constraint is applied to a navigational solution provided by the inertial navigation routine.

23. A portable device that may be associated with a user comprising:
an optical sensor; and
an optical navigation module, wherein the optical navigation module is configured to:
process a sequence of samples from the optical sensor of the portable device;
determine a navigational constraint for the portable device based at least in part on the processed samples, wherein processing the sequence of samples from the optical sensor comprises performing an optical flow analysis, wherein the portable device and the optical sensor may assume varying orientations with respect to the user depending at least in part on how the portable device is being used, and wherein the navigational constraint comprises at least one of:
a) a context for the portable device, wherein the context comprises at least one of:
i) the context corresponding to fidgeting motion;
ii) the context corresponding to substantially constant altitude movement; and
iii) the context corresponding to varying altitude movement; and

b) an estimated speed of the portable device; and
provide a navigation solution for the portable device based at least in part on the determined navigational constraint.

24. The portable device of claim 23 , wherein the optical navigation module determines the navigational constraint by determining the context for the portable device.

25. The portable device of claim 23 , wherein the optical navigation module performs the optical flow analysis by aggregating estimations of pixel translations between the samples.

26. The portable device of claim 23 , wherein the optical navigation module is further configured to estimate a device angle with respect to a direction of motion.

27. The portable device of claim 26 , wherein the optical navigation module determines the context of the portable device by assessing variance in a plurality of estimated device angles.

28. The portable device of claim 23 , wherein the optical navigation module determines the context of the portable device by calculating an optical flow ratio.

29. The portable device of claim 24 , wherein the optical navigation module determines the context of the portable device by comparing similarity between samples.

30. The portable device of claim 26 , wherein the optical navigation module is further configured to determine a usage of the portable device based at least in part on the estimated device angle.

31. The portable device of claim 30 , wherein the portable device further comprises an inertial sensor and wherein the optical navigation module determines the usage of the portable device based also at least in part on an orientation determination using the inertial sensor.

32. The portable device of claim 24 , wherein the optical navigation module determines the context of the portable device by identifying a feature in the samples.

33. The portable device of claim 24 , wherein the optical navigation module determines an additional context that corresponds to being static.

34. The portable device of claim 24 , wherein the optical navigation module determines the context corresponds to fidgeting motion.

35. The

Assignees

• Invensense Incorporated
• Invensense Inc

Inventors

• Kazemipur Bashir
• Al-Hamad Amr
• Georgy Jacques
• Syed Zainab
• Goodall Christopher
• El-Sheimy Naser

Classifications

• G01S11/12 Primary

  using electromagnetic waves other than radio waves · CPC title

• G01S5/16

  using electromagnetic waves other than radio waves · CPC title

• G01S19/48

  by combining or switching between position solutions derived from the satellite radio beacon positioning system and position solutions derived from a further system · CPC title

• G01S19/39

  the satellite radio beacon positioning system transmitting time-stamped messages, e.g. GPS [Global Positioning System], GLONASS [Global Orbiting Navigation Satellite System] or GALILEO · CPC title

• G06T7/20

  Analysis of motion (motion estimation for coding, decoding, compressing or decompressing digital video signals H04N19/43, H04N19/51) · CPC title