Environment map building method, environment map building apparatus and mobile robot apparatus

• US 20060025888A1
• Filed: 06/24/2005
• Published: 02/02/2006
• Est. Priority Date: 06/25/2004
• Status: Active Grant

• Current Assignee: Sony Corporation (Sony Group Corp.)
• Original Assignee: Sony Corporation (Sony Group Corp.)
• Inventors: Fukuchi, Masaki, Sabe, Kohtaro, Gutmann, Steffen, Bruce, James R.
• Granted Patent: US 7,912,583 B2
• Time in Patent Office: Days
• US Class Current: 700/245
• CPC Class Codes: G06T 7/593 from stereo images
• CPC Class Codes: G06V 20/10 Terrestrial scenes scenes under surveillance with static cameras G06V20/52; scenes perceived from the exterior of a vehicle G06V20/56; scenes perceived from the interior of a vehicle G06V20/59

Abstract

An environment map building method and an environment map building apparatus can express the surrounding embodiment with a high resolution in the height direction in a manner robust relative to observation noises. The present invention provides an environment map building apparatus for building a three-dimensional environment map to be used for three-dimensionally determining a region allowing a moving body to move therein according to external environment conditions, which comprises an external environment conditions detecting section that detects external environment conditions, a three-dimensional map building section that builds a three-dimensional map showing the state of occupancy of a three-dimensional grid on the basis of the external environment conditions detected by the external environment conditions detecting section, a relative-to-base-plane height map building section that builds a relative-to-base-plane height map showing heights from a two-dimensional base plane on the basis of the external environment conditions detected by the external environment conditions detecting section, and a height map information modifying section that modifies the information of the relative-to-base-plane height map on the basis of the information on the three-dimensional map.

Claims

1. An environment map building method for building a three-dimensional environment map to be used for three-dimensionally determining a region allowing a moving body to move therein according to external environment conditions, the method comprising:

an external environment conditions detecting step of detecting external environment conditions;

a three-dimensional map building step of building a three-dimensional map showing the state of occupancy of a three-dimensional grid on the basis of the external environment conditions detected in the external environment conditions detecting step;

a relative-to-base-plane height map building step of building a relative-to-base-plane height map showing heights from a two-dimensional base plane on the basis of the external environment conditions detected in the external environment conditions detecting step; and

a height map information modifying step of modifying the information of the relative-to-base-plane height map on the basis of the information on the three-dimensional map.

2. The method according to claim 1, wherein the height map information modifying step is adapted to determine the state of occupancy of the three-dimensional grid corresponding to the heights expressed in the relative-to-base-plane height map based on the state of occupancy of the three-dimensional grid updated by the three-dimensional map building step and modify the information of the relative-to-base-plane height map on the basis of the outcome of the determination.

3. The method according to claim 1, wherein

the external environment conditions detecting step includes a distance metering step of metering the three-dimensional distances from the point of observation to the object points of measurement;

and

the three-dimensional map building step is adapted to update the state of occupancy of the three-dimensional grid of the three-dimensional map on the basis of the three-dimensional distances metered in the distance metering step.

4. The method according to claim 1, wherein

the external environment conditions detecting step includes a distance metering step of metering the three-dimensional distances from the point of observation to the object points of measurement;

and

the relative-to-base-plane map building step includes a plane detecting step of detecting one or plurality of planes contained in the environment from the three-dimensional distances metered in the distance metering step and outputting the detected plane or planes as plane information.

5. The method according to claim 3, wherein the three-dimensional map building step is adapted to reduce the occupancy probability of the three-dimensional grid contained in the straight lines connecting the point of observation and the object points of measurement and raise the occupancy probability of the unit grids that correspond to the respective object points of measurement.

6. The method according to claim 1, wherein the height map information modifying step is adapted to acquire height information from the relative-to-base-plane height map, make it correspond to the height coordinates of the three-dimensional map, compare the occupancy probability of each unit grid with a threshold value to see if it is greater or smaller than the threshold value for determining if the unit grid represents an obstacle in the three-dimensional grid or not and determine the unit grid to be not an obstacle if the occupancy probability is smaller than the threshold value but determine the unit grid to be an obstacle and modify the corresponding height information of the relative-to-base-plane height map if the occupancy probability is greater than the threshold value.

7. The method according to claim 1, wherein the height map information modifying step is adapted to modify the height map information only for the map region that corresponds to the real space detected in the external environment conditions detecting step out of the three-dimensional map and the relative-to-base-plane height map.

8. The method according to claim 4, wherein

the plane detecting step includes:

a line segment extracting step of extracting a line segment for each group of distance data points estimated to be on a same plane in a three-dimensional space; and

a plane region extending step of extracting a plurality of line segments estimated to be belonging to a same plane from the group of line segments extracted in the line segment extracting step and computationally determining a plane from the plurality of line segments;

the line segment extracting step being adapted to detect a plane by adaptively extracting line segments according to the distribution of distance data points.

9. An environment map building apparatus for building a three-dimensional environment map to be used for three-dimensionally determining a region allowing a moving body to move therein according to external environment conditions, the apparatus comprising:

external environment conditions detecting means for detecting external environment conditions;

three-dimensional map building means for building a three-dimensional map showing the state of occupancy of a three-dimensional grid on the basis of the external environment conditions detected by the external environment conditions detecting means;

relative-to-base-plane height map building means for building a relative-to-base-plane height map showing heights from a two-dimensional base plane on the basis of the external environment conditions detected by the external environment conditions detecting means; and

height map information modifying means for modifying the information of the relative-to-base-plane height map on the basis of the information on the three-dimensional map.

10. The apparatus according to claim 9, wherein

the height map information modifying means is adapted to determine the state of occupancy of the three-dimensional grid corresponding to the heights expressed in the relative-to-base-plane height map based on the state of occupancy of the three-dimensional grid updated by the three-dimensional map building means and modify the information of the relative-to-base-plane height map on the basis of the outcome of the determination.

11. The apparatus according to claim 9, wherein

the external environment conditions detecting means includes distance metering means for metering the three-dimensional distances from the point of observation to the object points of measurement;

and

the three-dimensional map building means is adapted to update the state of occupancy of the three-dimensional grid of the three-dimensional map on the basis of the three-dimensional distances metered by the distance metering means.

12. The apparatus according to claim 9, wherein

the external environment conditions detecting means includes distance metering means for metering the three-dimensional distances from the point of observation to the object points of measurement;

and

the relative-to-base-plane map building means includes plane detecting means for detecting one or plurality of planes contained in the environment from the three-dimensional distances metered by the distance metering means and outputting the detected plane or planes as plane information.

13. A mobile robot apparatus movable by means of moving means, the robot apparatus comprising:

external environment conditions detecting means for detecting external environment conditions;

three-dimensional map building means for building a three-dimensional map showing the state of occupancy of a three-dimensional grid on the basis of the external environment conditions detected by the external environment conditions detecting means;

relative-to-base-plane height map building means for building a relative-to-base-plane height map showing heights from a two-dimensional base plane on the basis of the external environment conditions detected by the external environment conditions detecting means;

height map information modifying means for modifying the information of the relative-to-base-plane height map on the basis of the information on the three-dimensional map; and

movement control means for autonomously determining the moving route, using the map information modified by the height map information modifying means as environment map and controlling the moving actions.

14. An environment map building apparatus for building a three-dimensional environment map to be used for three-dimensionally determining a region allowing a moving body to move therein according to external environment conditions, the apparatus comprising:

an external environment conditions detecting section that detects external environment conditions;

a three-dimensional map building section that builds a three-dimensional map showing the state of occupancy of a three-dimensional grid on the basis of the external environment conditions detected by the external environment conditions detecting section;

a relative-to-base-plane height map building section that builds a relative-to-base-plane height map showing heights from a two-dimensional base plane on the basis of the external environment conditions detected by the external environment conditions detecting section; and

a height map information modifying section that modifies the information of the relative-to-base-plane height map on the basis of the information on the three-dimensional map.

15. A mobile robot apparatus movable by means of moving means, the robot apparatus comprising:

an external environment conditions detecting section that detects external environment conditions;

a three-dimensional map building section that builds a three-dimensional map showing the state of occupancy of a three-dimensional grid on the basis of the external environment conditions detected by the external environment conditions detecting section;

a relative-to-base-plane height map building section that builds a relative-to-base-plane height map showing heights from a two-dimensional base plane on the basis of the external environment conditions detected by the external environment conditions detecting section;

a height map information modifying section that modifies the information of the relative-to-base-plane height map on the basis of the information on the three-dimensional map; and

a movement control section that autonomously determines the moving route, using the map information modified by the height map information modifying section as environment map and controlling the moving actions.