METHOD FOR GENERATING ACCURATE LANE LEVEL MAPS

• US 20150117723A1
• Filed: 10/31/2013
• Published: 04/30/2015
• Est. Priority Date: 10/31/2013
• Status: Active Grant

• Current Assignee: Toyota Jidosha Kabushiki Kaisha (Toyota Motor Corporation)
• Original Assignee: Toyota Motor Engineering & Manufacturing North America Incorporated (Toyota Motor Corporation)
• Inventors: Joshi, Avdhut S., James, Michael R.
• Granted Patent: US 9,384,394 B2
• Time in Patent Office: Days
• US Class Current: 382/113
• CPC Class Codes: G01C 21/20 Instruments for performing navigational calculations G01C21/24, G01C21/26 take precedence
• CPC Class Codes: G01C 21/3819 Road shape data, e.g. outline of a route
• CPC Class Codes: G01C 21/3837 Data obtained from a single source
• CPC Class Codes: G06V 30/422 Technical drawings; Geographical maps
• CPC Class Codes: G09B 29/106 using electronic means

Abstract

A method for generating accurate lane level maps based on course map information and Lidar data captured during the pass of a sensor carrying vehicle along a road. The method generates accurate lane estimates including the center of each lane, the number of lanes, and the presence of any bicycle paths and entrance and exit ramps using a computer-implemented method where the course map data and the Lidar data are subjected to particle filtering.

Claims

1. A method for determining road lane characteristics of a road comprising:

obtaining Lidar data of road markers on a road;

accessing road map data;

determining road segment node locations from the map data;

tying a computer implemented on the Lidar generated road marker data to the road segment node locations; and

applying particle filtering to the road marker road segment locations to lane characteristics estimates generating a road lane map.

2. The method of claim 1 wherein the step of applying particle filtering comprises:

using one of a regular particle filter, a dual particle filter and a mixture of the regular particle filter and the dual particle filter.

3. The method of claim 2 further comprising:

using the dual particle filter to estimate the characteristics of one of a bicycle lane and a road exit or entrance adjacent to one lane of a road.

4. The method of claim 3 further comprising:

using the mixture of the regular particle filter and the dual particle filter to detect a transition of one of one lane of a road into at least one additional road lane, and a transition of two side-by-side road lanes into one road lane.

5. The method of claim 2 further comprising:

extracting road lane marker data from the Lidar data.

6. The method of claim 5 further comprising:

refining the lane marker data by use of GraphSlam.

7. The method of claim 1 further comprising:

extracting road lane marker data from the Lidar data.

8. The method of claim 7 further comprising:

refining the lane marker data by use of a GraphSlam algorithm.

9. The method of claim 1 wherein the step of tying the Lidar generated road marker data to the road segment node locations comprises:

generating each of the map road nodes one at a time;

computing an angle of one node to an adjacent node;

finding a lateral line marker to the one node;

forming a set of all line segments within a rectangle;

filtering the set of line segments within the rectangle;

clustering line segments to the lane markers;

computing a mean offset distance;

grouping lane markers longitudinally; and

calculating binary features of the Lidar generated marker data and map nodes.

10. The method of claim 1 wherein the lane characteristics estimates include at least one of the number of lanes, the width of the lanes, and the center of each lane.

11. The method of claim 1 wherein the step of obtaining Lidar data of road markers comprises:

equipping a vehicle with a GPS locator, and a rotating laser beam and a reflected laser beam detector;

moving the vehicle along one lane of a road; and

detecting the intensity of the laser beam reflected from reflective road markers on all lanes of the road as the vehicle moves along the one lane of the road.