Location And Motion Estimation Using Ground Imaging Sensor

• US 20140005932A1
• Filed: 06/29/2012
• Published: 01/02/2014
• Est. Priority Date: 06/29/2012
• Status: Active Grant

• Current Assignee: Southwest Research Institute
• Original Assignee: Southwest Research Institute
• Inventors: KOZAK, Kristopher C., ALBAN, Marc C., SLOCUM, Samuel E.
• Granted Patent: US 8,725,413 B2
• Time in Patent Office: Days
• US Class Current: 701/446
• CPC Class Codes: G01C 21/005 with correlation of navigation data from several sources, e.g. map or contour matching G01C21/30 takes precedence
• CPC Class Codes: G01C 21/30 Map- or contour-matching
• CPC Class Codes: G01C 21/3602 Input other than that of destination using image analysis, e.g. detection of road signs, lanes, buildings, real preceding vehicles using a camera
• CPC Class Codes: G01S 13/86 Combinations of radar systems with non-radar systems, e.g. sonar, direction finder
• CPC Class Codes: G01S 19/485 whereby the further system is an optical system or imaging system

Abstract

A system and method for estimating location and motion of an object. An image of a ground surface is obtained and a first set of features is extracted from the image. A map database is searched for a second set of features that match the first set of features and a geo-location is retrieved from the map database, wherein the geo-location is associated with the second set of features. The location is estimated based on the retrieved geo-location. The motion of the object, such as distance travelled, path travelled and/or speed may be estimated in a similar manner by comparing the location of extracted features that are present in two or more images over a selected time period.

Claims

1. A method for estimating a location comprising:

obtaining an image of a ground surface;

extracting a first set of features from said image;

searching a map database for a second set of features that match said first set of features;

retrieving a geo-location from said map database, wherein said geo-location is associated with said second set of features; and

estimating said location based on said retrieved geo-location.

2. The method of claim 1, wherein said searching is restricted to a subset of said map database, said subset comprising geo-locations within a geographic area of interest.

3. The method of claim 1, wherein said image is obtained from an electro-optic sensor.

4. The method of claim 1, wherein said ground surfaces include at least one of a road, a parking lot, a field or a trail.

5. A method for estimating a location comprising:

obtaining images of ground surfaces;

associating a geo-location with each of said images;

extracting features from said images;

storing said features and said associated geo-locations in a map database;

retrieving said features and said associated geo-locations from said map database in response to queries; and

estimating a location from said features and said associated geo-locations.

6. The method of claim 5, wherein said associated geo-location is obtained from a Global Positioning System (GPS) receiver.

7. The method of claim 5, wherein said images are obtained from an electro-optic sensor.

8. The method of claim 5, wherein said ground surfaces include at least one of a road, a parking lot, a field or a trail.

9. A method for estimating motion comprising:

obtaining a first image of a ground surface;

extracting a first set of features from said first image;

obtaining a second image of a ground surface, wherein a portion of said second image overlaps said first image;

extracting a second set of features from said second image;

identifying one or more common features, wherein said common features are present in said first and said second set of features; and

estimating motion from a difference between the location of said common features in said first image and said second image.

10. The method of claim 9, wherein said motion is one of a distance traveled, a path traveled, or a speed.

11. The method of claim 9, wherein said images are obtained from an electro-optic sensor.

12. The method of claim 9, wherein said ground surfaces include at least one of a road, a parking lot, a field or a trail.

13. A system for estimating a location comprising:

an imaging sensor configured to obtain an image of a ground surface;

a processing module configured to extract a first set of features from said image; and

a map database configured to store a plurality of sets of features and associated geo-locations, wherein said processing module is further configured to search said map database for a second set of features that match said first set of features and retrieve a geo-location associated with said second set of features such that said location is estimated based on said retrieved geo-location.

14. The system of claim 13, wherein said imaging sensor is an electro-optic sensor.

15. The system of claim 13, further comprising an illumination source configured to strobe in synchronization with said sensor imaging.

16. The system of claim 13, wherein said searching is restricted to a subset of said map database, said subset comprising geo-locations within a geographic area of interest.

17. The system of claim 16, further comprising a GPS receiver, wherein said geographic area of interest is based on an approximate location provided by said GPS receiver.

18. The system of claim 13, wherein said ground surfaces include at least one of a road, a parking lot, a field or a trail.

19. A system for estimating motion comprising:

an imaging sensor configured to obtain a first and second image of a ground surface, wherein a portion of said second image overlaps said first image;

a processing module configured to extract a first set of features from said first image and a second set of features from said second image and identify one or more common features, wherein said common features are present in said first and said second set of features; and

a motion estimation module configured to estimate said motion based on a difference between the location of said common features in said first image and said second image.

20. The system of claim 19, wherein motion is one of a distance traveled, a path traveled, or a speed.

21. The system of claim 19, wherein said imaging sensor is an electro-optic sensor.

22. The system of claim 19, further comprising an illumination source configured to strobe in synchronization with said sensor imaging.

23. The system of claim 19, wherein said ground surfaces include at least one of a road, a parking lot, a field or a trail.