Method and system for mapping environments containing dynamic obstacles

• US 8,108,148 B2
• Filed: 02/27/2009
• Issued: 01/31/2012
• Est. Priority Date: 02/27/2009
• Status: Active Grant

• Current Assignee: Toyota Motor Corporation
• Original Assignee: Toyota Motor Engineering & Manufacturing North America Incorporated (Toyota Motor Corporation)
• Inventors: James, Michael Robert
• Primary Examiner(s): Lubin, Valerie
• Application Number:
  US12/395,574
• Publication Number:
  US 20100223007A1
• Time in Patent Office: 1,068 Days
• Field of Search: 701/23
• US Class Current: 701/450
• CPC Class Codes: G01S 17/89 for mapping or imaging

Abstract

The present invention relates to a method and system for mapping environments containing dynamic obstacles. In one embodiment, the present invention is a method for mapping an environment containing dynamic obstacles using a processor including the steps of forming a current instantaneous map of the environment, determining cells which are free space within the current instantaneous map, determining cells which are occupied space within the current instantaneous map, and integrating the current instantaneous map with an old integrated map of the environment to form a new integrated map of the environment.

Claims

1. A method for mapping an environment containing dynamic obstacles comprising the steps of:

forming a current instantaneous map of the environment using a processor;

determining free cells which are free-space within the current instantaneous map using the processor;

determining occupied cells which are occupied-space within the current instantaneous map using the processor; and

forming a new integrated map using the processor by integrating the current instantaneous map of the environment with an old integrated map of the environment, the forming including

marking cells in the new integrated map as free-space or occupied-space based on the corresponding cells in the current instantaneous map and

marking some of unmarked cells in the new integrated map as free-space based at least on the some of the unmarked cells being disposed along a line between a first cell and a second cell, the line being substantially perpendicular to a ground plane.

2. The method of claim 1 wherein the first cell is a corresponding cell in the new integrated map which is marked as free-space in the current instantaneous map and which is marked as occupied-space in the old integrated map.

3. The method of claim 2 wherein the second cell is part of the ground plane.

4. The method of claim 1 wherein the first cell and the second cell are marked as occupied-space in the old integrated map, but have one or more cells therebetween marked as free-space in the current instantaneous map.

5. The method of claim 1 wherein the step of forming the current instantaneous map of the environment includes taking a union of at least two instantaneous maps of the environment.

6. The method of claim 1 wherein the step of forming the new integrated map includes marking any remaining unmarked cells in the new integrated map as free-space, occupied-space, or unknown-space based on the corresponding cells in the old integrated map.

15. The method of claim 1 further comprising saving the new integrated map as a second old integrated map for use in subsequent formation of a second new integrated map.

7. A method for mapping an environment of an automobile containing dynamic obstacles comprising the steps of:

forming a map of the environment at a first time using a processor;

determining free-space cells within the map of the environment at the first time using the processor;

determining occupied-space cells within the map of the environment at the first time using the processor; and

integrating the map of the environment at the first time with a map of the environment at a second time to form an integrated map using the processor by

marking cells in the integrated map as free-space or occupied-space based on the corresponding cells in the map of the environment at the first time,

marking unmarked cells in the integrated map as free-space which are below a first cell and above a second cell, have a same associated horizontal distance as the first cell, and which are located in a vertical line including the first cell that is substantially perpendicular to a ground plane and

marking remaining unmarked cells as free-space, occupied-space, or unknown-space based on the corresponding cells in the map of the environment at the second time.

8. The method of claim 7 wherein the first cell is a corresponding cell in the integrated map which is marked as free-space in the map of the environment at the first time and which is marked as occupied-space in the map of the environment at the second time.

9. The method of claim 7 wherein the second cell is part of the ground plane.

10. The method of claim 7 wherein the first cell and the second cell are ends of an obstacle marked as occupied-space in the map of the environment at the second time, but having at least one cell marked as free-space in the map of the environment at the first time.

11. The method of claim 7 wherein:

the map of the environment at the first time is an instantaneous map of the environment and

the map of the environment at the second time is an integrated map of the environment.

16. The method of claim 11 wherein the step of forming the map of the environment at the first time includes taking a union of at least two instantaneous maps of the environment.

12. A system in an automobile for mapping an environment containing dynamic obstacles comprising:

a sensor unit configured to collect environmental data;

a location unit connected to the sensor unit, the location unit configured to output location data of the sensor in relation to the environment; and

a control unit connected to the sensor unit and the location unit, the control unit configured to generate a new integrated map of the environment by

generating a current instantaneous map of the environment formed from the environmental data collected by the sensor,

marking cells in the new integrated map as free-space or occupied-space based on the corresponding cells in the current instantaneous map and

marking unmarked cells in the new integrated map as free-space based at least on the unmarked cells being disposed along a line between a first cell and a second cell, the line being substantially perpendicular to a ground plane.

13. The system of claim 12 wherein the control unit marks the remaining cells which are unmarked as free-space, occupied-space, or unknown-space based on the corresponding cells in an old integrated map of the environment.

14. The system of claim 12 wherein the current instantaneous map of the environment is generated from a union of at least two instantaneous maps of the environment.

17. The system of claim 12 wherein the sensor comprises a plurality of lasers arranged in a vertical plane, the plurality of lasers configured to individually or collectively rotate in a plane substantially parallel to the ground plane.

18. The system of claim 17 wherein the plurality of lasers are positioned at different angles for collectively covering an angle on a plane perpendicular to the ground plane.