Environment map building method, environment map building apparatus and mobile robot apparatus
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.
1. A method for a device to build an environment map of an environment, the method comprising:
detecting external environment conditions in the environment;
building the three-dimensional map showing a state of occupancy of a three-dimensional grid based on the external environment conditions, wherein the three-dimensional grid comprises cells corresponding to box-shaped spaces of the environment;
building a relative-to-base-plane height map showing heights from a two-dimensional base plane based on the external environment conditions;
modifying the relative-to-base-plane height map based on the three-dimensional map;
updating occupancy probability of the cells when height information of the relative-to-base-plane height map corresponds to the cells; and
controlling moving actions of the device for stepping up a staircase in the environment by using the relative-to-base-plane height map as the environment map, wherein the device steps up the staircase by transmitting infrared rays, the infrared rays forming a random pattern used to acquire a distance image.
2. The method according to claim 1 , wherein modifying the relative-to-base-plane height map comprises determining an updated state of occupancy of the three-dimensional grid corresponding to the heights and modifying the relative-to-base-plane height map based on the updated state of occupancy.
3. The method according to claim 1 ,
wherein detecting the external environment conditions comprises metering three-dimensional distances from a point of observation to points of measurement of an object; and
wherein building the three-dimensional map comprises updating the state of occupancy based on the three-dimensional distances.
4. The method according to claim 1 ,
wherein detecting the external environment conditions comprises metering three-dimensional distances from a point of observation to points of measurement of an object; and
wherein building the relative-to-base-plane height map comprises detecting one or more planes contained in the environment based on the three-dimensional distances.
5. The method according to claim 3 , wherein building the three-dimensional map comprises reducing an occupancy probability contained in straight lines connecting the point of observation and the points of measurement and raising the occupancy probability of unit grids that correspond to the points of measurement.
6. The method according to claim 1 , wherein the modifying the relative-to-base-plane height map comprises:
acquiring the height information from the relative-to-base-plane height map;
making the height information correspond to height coordinates of the three-dimensional map;
comparing an occupancy probability of each unit grid with a threshold value;
determining whether the unit grid represents an obstacle in the three-dimensional grid, wherein the unit grid is not an obstacle if the occupancy probability is smaller than the threshold value; and
modifying corresponding height information of the relative-to-base-plane height map when the occupancy probability is greater than the threshold value.
7. The method according to claim 1 ,
wherein detecting the external environmental conditions comprises detecting real space of the three-dimensional map and the relative-to-base-plane height map;
wherein modifying the relative-to-base-plane height map comprises modifying a region of the relative-to-base-plane height map that corresponds to the real space.
8. The method according to claim 4 , wherein detecting the one or more planes comprises:
extracting a line segment for each group of distance data points estimated to be on a same plane in a three-dimensional space;
extracting a plurality of line segments estimated to be belonging to the same plane; and
computationally determining a plane from the plurality of line segments,
wherein extracting the line segment comprises detecting the plane by adaptively extracting line segments according to the distribution of distance data points.
9. A device for building an environment map of an environment, the apparatus comprising:
means for detecting external environment conditions in the environment;
means for building the three-dimensional map showing a state of occupancy of a three-dimensional grid based on the external environment conditions, wherein the three-dimensional grid comprises cells corresponding to box-shaped spaces of the environment;
means for building a relative-to-base-plane height map showing heights from a two-dimensional base plane based on the external environment conditions;
means for modifying the relative-to-base-plane height map based on the three-dimensional map;
means for updating occupancy probability of the cells when height information of the relative-to-base-plane height map corresponds to the cells; and
means for controlling moving actions of the device for stepping up a staircase in the environment by using the relative-to-base-plane height map as the environment map, wherein the device steps up the staircase by transmitting infrared rays, the infrared rays forming a random pattern used to acquire a distance image.
10. The apparatus according to claim 9 , wherein modifying the relative-to-base-plane height map comprises determining an updated state of occupancy of the three-dimensional grid corresponding to the heights and modifying the relative-to-base-plane height map based on the updated state of occupancy.
11. The apparatus according to claim 9 , wherein detecting the external environment conditions comprises metering three-dimensional distances from a point of observation to points of measurement of an object; and
wherein building the three-dimensional map comprises updating the state of occupancy based on the three-dimensional distances.
12. The apparatus according to claim 9 , wherein detecting the external environment conditions comprises metering three-dimensional distances from a point of observation to points of measurement of an object; and
wherein building the relative-to-base-plane height map comprises detecting one or more planes contained in the environment based on the three-dimensional distances.
13. A mobile apparatus comprising:
means for detecting external environment conditions in an environment;
means for building a three-dimensional map of an environment showing a state of occupancy of a three-dimensional grid based on the external environment conditions, wherein the three-dimensional grid comprises cells corresponding to box-shaped spaces of the environment;
means for building a relative-to-base-plane height map showing heights from a two-dimensional base plane based on the external environment conditions;
means for modifying the relative-to-base-plane height map based on the three-dimensional map;
means for updating occupancy probability of the cells when height information of the relative-to-base-plane height map corresponds to the cells; and
means for autonomously determining a moving route for the mobile apparatus, using the relative-to-base-plane height map as an environment map and controlling moving actions of the mobile apparatus based on the moving route, the moving route comprises stepping up a staircase, wherein the mobile apparatus steps up the staircase by transmitting infrared rays, the infrared rays forming a random pattern used to acquire a distance image.