SYSTEMS AND METHODS FOR ADDING A LANDMARKS FOR VISUAL SIMULTANEOUS LOCALIZATION AND MAPPING

• US 20100284621A1
• Filed: 07/20/2010
• Published: 11/11/2010
• Est. Priority Date: 12/17/2002
• Status: Active Grant

• Current Assignee: iRobot Corporation
• Original Assignee: Evolution Robotics Inc. (iRobot Corporation)
• Inventors: Karisson, L. Niklas, Di Bernardo, Enrico, Pirjanian, Paolo, Goncalves, Luis Filipe Domingues
• Granted Patent: US 8,095,336 B2
• Time in Patent Office: Days
• US Class Current: 382/218
• CPC Class Codes: G01C 21/12 executed aboard the object being navigated; Dead reckoning
• CPC Class Codes: G01C 21/206 specially adapted for indoor navigation
• CPC Class Codes: G05D 1/0231 using optical position detecting means position-fixing by using electromagnetic waves other than radio waves, e.g. optical position detecting means G01S5/16
• CPC Class Codes: G05D 1/0234 using optical markers or beacons optical beacons per se G01S1/70
• CPC Class Codes: G05D 1/024 in combination with a laser lasers per se H01S
• CPC Class Codes: G05D 1/0242 using non-visible light signals, e.g. IR or UV signals
• CPC Class Codes: G05D 1/0246 using a video camera in combination with image processing means
• CPC Class Codes: G05D 1/0248 in combination with a laser lasers per se H01S
• CPC Class Codes: G05D 1/0272 comprising means for registering the travel distance, e.g. revolutions of wheels measuring distance traversed on the ground by vehicles, e.g. using odometers G01C22/00
• CPC Class Codes: G05D 1/0274 using mapping information stored in a memory device navigation using map-matching G01C21/30
• CPC Class Codes: G05D 1/0278 using satellite positioning signals, e.g. GPS
• CPC Class Codes: G06T 2207/30204 Marker
• CPC Class Codes: G06T 7/55 from multiple images
• CPC Class Codes: G06T 7/70 Determining position or orientation of objects or cameras camera calibration G06T7/80
• CPC Class Codes: G06T 7/74 involving reference images or patches
• CPC Class Codes: Y10S 901/01 Mobile robot
• CPC Class Codes: Y10S 901/46 Sensing device
• CPC Class Codes: Y10S 901/47 Optical
• CPC Class Codes: Y10S 901/50 Miscellaneous

Abstract

The invention is related to methods and apparatus that use a visual sensor and dead reckoning sensors to process Simultaneous Localization and Mapping (SLAM). These techniques can be used in robot navigation. Advantageously, such visual techniques can be used to autonomously generate and update a map. Unlike with laser rangefinders, the visual techniques are economically practical in a wide range of applications and can be used in relatively dynamic environments, such as environments in which people move. One embodiment further advantageously uses multiple particles to maintain multiple hypotheses with respect to localization and mapping. Further advantageously, one embodiment maintains the particles in a relatively computationally-efficient manner, thereby permitting the SLAM processes to be performed in software using relatively inexpensive microprocessor-based computer systems.

Claims

1. A method of determining whether to add a landmark to a map for navigation, the method comprising:

retrieving an image from a visual sensor;

comparing features from the image to a plurality of stored features;

generating a list of matching landmarks from the comparison;

filtering matching landmarks from the list based at least in part on reliability tests; and

proceeding to a landmark creation process when there are no remaining matching landmarks in the list;

wherein retrieving, comparing, generating, filtering, and proceeding are performed under the control of electronic hardware.

2. The method as defined in claim 1, wherein the visual sensor is coupled to a mobile robot.

3. The method as defined in claim 1, wherein filtering matching landmarks further comprises:

comparing the number of features common to the image and to a landmark to a predetermined number; and

filtering the landmark from the list when the number of common features for the landmark is below the predetermined number.

4. The method as defined in claim 1, wherein filtering matching landmarks further comprises:

initiating a computation of a camera pose corresponding to the matching features and to the landmark; and

filtering the landmark from the list upon a failure of the computation to converge to a result.

5. The method as defined in claim 1, further comprising providing match results when at least one matching landmark remains in the list.

6. A computer program embodied in a tangible non-transitory computer-readable medium for determining whether to add a landmark to a map for navigation, the computer program comprising:

a module with instructions configured to retrieve an image from a visual sensor;

a module with instructions configured to compare features from the image to a plurality of stored features;

a module with instructions configured to generate a list of matching landmarks from the comparison;

a module with instructions configured to filter matching landmarks from the list based at least in part on reliability tests; and

a module with instructions configured to proceed to a landmark creation process when there are no remaining matching landmarks in the list.

7. The computer program as defined in claim 6, wherein the visual sensor is coupled to a mobile robot.

8. The computer program as defined in claim 6, wherein the module with instructions configured to filter matching landmarks further comprises:

a module with instructions configured to compare the number of features common to the image and to a landmark to a predetermined number; and

a module with instructions configured to filter the landmark from the list when the number of common features for the landmark is below the predetermined number.

9. The computer program as defined in claim 6, wherein the module with instruction configured to filter matching landmarks further comprises:

a module with instructions configured to initiate a computation of a camera pose corresponding to the matching features and to the landmark; and

a module with instructions configured to filter the landmark from the list upon a failure of the computation to converge to a result.

10. The computer program as defined in claim 6, further comprising a module with instructions configured to provide match results when at least one matching landmark remains in the list.