Method for representing a vehicle environment with position points

• US 9,829,575 B2
• Filed: 06/27/2013
• Issued: 11/28/2017
• Est. Priority Date: 07/30/2012
• Status: Active Grant

• Current Assignee: Continental Teves AG & Co. OHG (Continental AG), Conti Temic Microelectronic GmbH (Continental AG)
• Original Assignee: Continental Teves AG & Co. OHG (Continental AG), Conti Temic Microelectronic GmbH (Continental AG)
• Inventors: Hegemann, Stefan, Grewe, Ralph, Hohm, Andree, Lueke, Stefan
• Primary Examiner(s): Brainard, Timothy A
• Application Number:
  US14/381,734
• Publication Number:
  US 20150022392A1
• Time in Patent Office: 1,615 Days
• Field of Search: 342146, 342385
• CPC Class Codes: G01S 13/02 Systems using reflection of radio waves, e.g. primary radar systems; Analogous systems
• CPC Class Codes: G01S 13/06 Systems determining position data of a target
• CPC Class Codes: G01S 13/931 of land vehicles
• CPC Class Codes: G01S 2013/9322 using additional data, e.g. driver condition, road state or weather data
• CPC Class Codes: G01S 7/003 Transmission of data between radar, sonar or lidar systems and remote stations

Abstract

A sensor system detects objects in an environment ahead of a vehicle. The environment is represented by a predetermined fixed number of position points in an environment model. Initially and when no objects are detected, the position points may be distributed stochastically over the detection area of the sensor system. When objects are detected, the position points are re-distributed based on the detected objects, e.g. with a higher density of position points to represent the detected objects. Because the total number of position points is a predefined fixed number that remains constant, the processing, storage and transmission of the environment model involves a constant data volume and efficient use of memory and transmission bandwidth.

Claims

1. A driver assistance method for a vehicle, comprising the steps:

a) with a sensor system of the vehicle, detecting zero or more detected objects in a detection area in an environment outside of the vehicle, and producing corresponding sensor data representative of the zero or more detected objects;

b) in a data structure in a memory of a driver assistance system of the vehicle, populating the data structure with a predetermined fixed number of position points, wherein the predetermined fixed number is independent and regardless of a number of the zero or more detected objects that are detected in the detection area;

c) in the data structure in the memory of the driver assistance system, forming an environment model representative of the detection area in the environment by distributing the predetermined fixed number of the position points in the data structure dependent on the sensor data; and

d) with the driver assistance system of the vehicle, controlling a driver assistance function dependent on the environment model.

2. The driver assistance method according to claim 1, wherein the steps b) and c) are performed by an evaluation unit of the driver assistance system, and the step d) is performed by a control device of the driver assistance system.

3. The driver assistance method according to claim 1, further comprising, initially distributing the predetermined fixed number of the position points according to a stochastic distribution in the data structure before the sensor system has produced the sensor data.

4. The driver assistance method according to claim 1, wherein, when the sensor data represents zero detected objects, then the distributing of the predetermined fixed number of the position points in the step c) is according to a stochastic distribution in the data structure.

5. The driver assistance method according to claim 4, wherein, when the sensor data represents at least one of the detected objects, then the distributing of the predetermined fixed number of the position points in the step c) is dependent on the at least one detected object.

6. The driver assistance method according to claim 1, wherein, when the sensor data represents at least one of the detected objects, then the distributing of the predetermined fixed number of the position points in the step c) is dependent on the at least one detected object.

7. The driver assistance method according to claim 6, wherein the distributing of the predetermined fixed number of the position points in the step c) comprises arranging the position points in the environment model dependent on a respective position of each of the at least one detected object in the detection area in the environment.

8. The driver assistance method according to claim 6, wherein the distributing of the predetermined fixed number of the position points in the step c) comprises arranging the position points in the environment model dependent on a respective position, size and shape of each of the at least one detected object in the detection area in the environment.

9. The driver assistance method according to claim 1,

further comprising determining, from the sensor data, a respective degree of traversability of the detected objects and of regions of the detection area without the detected objects,

wherein the distributing of the predetermined fixed number of the position points in the step c) comprises arranging the position points in the environment model with a spatial density that is dependent on the respective degree of traversability of the detected objects and of the regions of the detection area without the detected objects.

10. The driver assistance method according to claim 1, wherein the distributing of the predetermined fixed number of the position points in the step c) comprises arranging the position points with a higher spatial density at places in the detection area where extensive structural descriptions are necessary.

11. The driver assistance method according to claim 1, wherein each respective one of the position points has a plurality of attributes associated therewith, and a first one of the attributes is a position information indicating a position, relative to the vehicle, of a respective point in the detection area of the environment that is being represented by the respective position point in the environment model.

12. The driver assistance method according to claim 11, wherein a second one of the attributes is a height information indicating an above-ground height of a respective one of the detected objects at the respective point in the detection area of the environment.

13. The driver assistance method according to claim 11, wherein a second one of the attributes is a traversability information indicating a traversability, by the vehicle, of a respective one of the detected objects at the respective point in the detection area of the environment.

14. The driver assistance method according to claim 1, wherein the sensor system comprises a radar sensor, the sensor data represents a respective position as well as a respective amplitude or energy of reflected radar radiation that is respectively reflected back from the one or more detected objects in the detection area in the environment, and the distributing of the position points in the step c) comprises arranging the position points in the environment model dependent on the respective position as well as the respective amplitude or energy of the reflected radar radiation.

15. The driver assistance method according to claim 14, wherein the distributing of the position points in the step c) comprises arranging the position points in the environment model such that more position points are arranged in a first region in which the respective amplitude or energy of the reflected radar radiation has a higher value, than in a second region in which the respective amplitude or energy of the reflected radar radiation has a lower value relative to the higher value.

16. The driver assistance method according to claim 1,

wherein the sensor system comprises plural sensors of plural different sensor types, wherein respective visual fields of the plural sensors do not overlap or only slightly overlap or strongly overlap, and

wherein the method further comprises:

in the data structure in the memory of the driver assistance system, providing a respective specific sensor model respectively for each one of the sensors and each one of the sensor types for adjusting the distribution of the position points in the data structure dependent on the detected objects in the environment.

17. The driver assistance method according to claim 16, wherein the respective position points of the respective sensors of the different sensor types are merged by accumulating, in respective time cycles, position points of each one of the sensors in a common merged representation from which the environment model is formed.

18. The driver assistance method according to claim 17, wherein a total number of the position points from all of the sensors exceeds the predetermined fixed number of position points, and wherein the method further comprises reducing the number of the position points for the common merged representation to the predetermined fixed number of position points by selecting only some of the position points for the common merged representation.

19. The driver assistance method according to claim 18, wherein the selecting of only some of the position points for the common merged representation comprises selecting those position points that best approximate all of the position points from all of the sensors.

20. The driver assistance method according to claim 18,

further comprising assigning respective weights to all of the position points,

wherein the respective weight for a respective position point is respectively determined dependent on at least one of:

i) a stored state variable representing an occupancy probability or an obstacle height, and ii) a number of others of the position points that are adjacent to the respective position point, and

wherein the selecting of only some of the position points comprises selecting the position points in order according to the respective weights assigned thereto until the predetermined fixed number of the position points is reached.