METHOD FOR DETECTING A ROADWAY AND CORRESPONDING DETECTION SYSTEMS

• US 20150367855A1
• Filed: 06/19/2015
• Published: 12/24/2015
• Est. Priority Date: 06/24/2014
• Status: Active Grant

• Current Assignee: Robert Bosch GmbH
• Original Assignee: Robert Bosch GmbH
• Inventors: PARCHAMI, Marzieh Asadeh
• Granted Patent: US 9,555,812 B2
• Time in Patent Office: Days
• US Class Current: 1/1
• CPC Class Codes: B60T 2210/12 Friction
• CPC Class Codes: B60W 2420/403 Image sensing, e.g. optical camera
• CPC Class Codes: B60W 2520/26 Wheel slip
• CPC Class Codes: B60W 2552/05 Type of road, e.g. motorways, local streets, paved or unpaved roads
• CPC Class Codes: B60W 2552/40 Coefficient of friction
• CPC Class Codes: B60W 2720/26 Wheel slip
• CPC Class Codes: B60W 40/068 Road friction coefficient
• CPC Class Codes: G01N 2021/1765 Method using an image detector and processing of image signal
• CPC Class Codes: G01N 2021/551 Retroreflectance
• CPC Class Codes: G01N 21/55 Specular reflectivity
• CPC Class Codes: G01S 17/46 Indirect determination of position data
• CPC Class Codes: G01S 17/931 of land vehicles
• CPC Class Codes: G06T 2207/30256 Lane; Road marking
• CPC Class Codes: G06T 7/0004 Industrial image inspection
• CPC Class Codes: G06V 20/588 Recognition of the road, e.g. of lane markings; Recognition of the vehicle driving pattern in relation to the road

Abstract

A method is provided for detecting a roadway of a vehicle including at least the following steps: generating a light signal and emitting the light signal onto a lit area of the roadway, receiving retroreflected radiation of the lit area and generating an image signal, evaluating the image signal. For this purpose, it is provided that the light signal having light structures is generated, the image signal is evaluated as a two-dimensional light pattern, a detection of pattern characteristics corresponding to the light structures being carried out in the light pattern during the evaluation of the image signals, a signal strength of the image pattern being evaluated in a space-resolved manner and a reflecting behavior of the lit area being inferred therefrom, and a roadway surface being inferred from the reflecting behavior.

Claims

1. A method for detecting a roadway of a vehicle, comprising:

generating a light signal having a light structure and emitting the light signal onto a lit area of the roadway;

receiving reflected radiation of the lit area and generating an image signal;

evaluating the image signal as a two-dimensional light pattern;

carrying out a detection of a pattern characteristic corresponding to the light structure in the light pattern during the evaluation of the image signal;

evaluating a signal strength of the light pattern in a space-resolved manner and a reflecting behavior of the lit area being inferred therefrom, and

inferring a roadway surface from the reflecting behavior.

2. The method as recited in claim 1, classifying the roadway surface as a function of stored calibration values for different roadway surfaces.

3. The method as recited in claim 1, wherein:

the light pattern has lines as the pattern characteristic,

the pattern characteristic essentially extends at least one of in a vertical direction of an image and in a traveling direction of a lit area, in multiple straight lines which extend at different angles to the traveling direction and which intersect at at least one intersection point.

4. The method as recited in claim 1, wherein the light pattern is rotationally asymmetrical and asymmetrical to reflections and rotations, for an unambiguous assignment to the vehicle.

5. The method as recited in claim 1, wherein the light signal is emitted in a wavelength range below visible light, and wherein the retroreflected light is received in the wavelength range.

6. The method as recited in claim 5, wherein the wavelength range is in a near infrared spectrum, in the range of 780 nm to 820 nm

7. The method as recited in claim 1, wherein a respective, space-resolved distance of points of the lit area to the vehicle is inferred with the aid of stored values of a radiometrical calibration from one of a signal strength and a gray scale value of the image signal.

8. The method as recited in claim 1, wherein a respective distance of points of the lit area to the vehicle is inferred with the aid of one of stored values of a geometrical calibration and a stored pattern of the light pattern.

9. The method as recited in claim 1, further comprising ascertaining a probability from the image signal whether a retroreflected light was emitted by one of the roadway and an obstacle.

10. The method as recited in claim 1, wherein the light pattern is classified in a space-resolved manner into at least one of the following classes:

asphalt;

one of a film of water and a wetness from rain;

frozen water including one of frost, ice, and snow;

gravel or dirt

11. The method as recited in claim 10, wherein in the case of a classification as frozen water, a sub-classification into different subclasses takes place, into at least two of the following subclasses:

one of light frost and cloudy frost, one of black ice and freezing moisture.

12. The method as recited in claim 10, further comprising assigning one of friction coefficients and probability values of the friction coefficients to the different classes.

13. A method for vehicle dynamics control of a vehicle, wherein, using a method, a roadway of the vehicle is classified in a space-resolved manner and evaluation signals are output as a function of the classification to a control device of a vehicle dynamics control system which carries out a vehicle dynamics control as a function of friction coefficients of the roadway, wherein the used method is for detecting the roadway of the vehicle, and comprises:

generating a light signal having a light structure and emitting the light signal onto a lit area of the roadway;

receiving reflected radiation of the lit area and generating an image signal;

evaluating the image signal as a two-dimensional light pattern;

carrying out a detection of a pattern characteristic corresponding to the light structure in the light pattern during the evaluation of the image signal;

evaluating a signal strength of the light pattern in a space-resolved manner and a reflecting behavior of the lit area being inferred therefrom, and

inferring a roadway surface from the reflecting behavior.

14. A detection system for a vehicle, comprising:

a pattern generator for emitting a light signal onto a roadway of the vehicle;

a camera for recording radiation reflected by the roadway, wherein;

the pattern generator includes an LED device and a projection lens for generating the light signal having light structures,

the projection lens has a diffractive optical element, and

the camera receives a light pattern in the retroreflected light which has pattern characteristics corresponding to the light structures; and

a control device for evaluating a recorded pattern characteristics, the control device, when evaluating the light pattern, carrying out a detection of the pattern characteristics in the light pattern corresponding to the light structures, and a signal strength of the light pattern being evaluated in a space-resolved manner, and a reflecting behavior of the lit area being inferred therefrom, and wherein roadway surface is inferred from the reflecting behavior.

15. A vehicle, comprising:

a detection system, including;

a pattern generator for emitting a light signal onto a roadway of the vehicle;

a camera for recording radiation reflected by the roadway, wherein;

the pattern generator includes an LED device and a projection lens for generating the light signal having light structures,

the projection lens has a diffractive optical element, and

the camera receives a light pattern in the retroreflected light which has pattern characteristics corresponding to the light structures; and

a control device for evaluating a recorded pattern characteristics, the control device, when evaluating the light pattern, carrying out a detection of the pattern characteristics in the light pattern corresponding to the light structures, and a signal strength of the light pattern being evaluated in a space-resolved manner, and a reflecting behavior of the lit area being inferred therefrom, and wherein a roadway surface is inferred from the reflecting behavior; and

a vehicle control system including a vehicle dynamics control device which receives evaluation signals from the control device of the detection system and carries out a vehicle dynamics control as a function of a classification of the roadway.

16. The vehicle as recited in claim 15, wherein the classification is a space-resolved classification of the roadway into values of one of iciness coefficients and friction coefficients.