Method and device for visualizing the surroundings of a vehicle by fusing an infrared image and a visual image

1. A method for visualizing surroundings of a vehicle, the method comprising the acts of:

obtaining, by a visual camera, a visual image containing digital data of the surroundings, in order to show visually perceptible objects;

obtaining, by an infrared camera, an infrared image containing digital data of the surroundings, in order to show infrared radiation emitted by the visually perceptible objects and/or other objects, wherein the visual camera and the infrared camera form a camera system;

calibrating the camera system with respect to a fixed distance corresponding to one of a close range and a far range;

fusing, by an image processing unit in the vehicle, the visual image and the infrared image into a target image, which target image is representable in a display unit, in order to simplify an allocation of the infrared radiation emitting objects in a recorded environment, and

interrupting the fusing of the visual image and the infrared image automatically by the image processing unit in response to an orientation error exceeding a threshold, which is a function of an environment parameter, in order to represent only one of the visual and infrared images, or none of the images, as the target image, wherein the orientation error is a parallax error owing to the offset optical axes of cameras used to obtain the visual image and the infrared image, respectively, said orientation error occurring in the close range if the fixed distance to which the camera system is calibrated is the far range, and occurring in the far range if the fixed distance to which the camera is calibrated is the close range.

2. The method according to claim 1 , wherein the interrupting act further comprises the act of blanking-out all of the digital data of the surroundings of the respective image in order to avoid image distortion.

3. The method according to claim 1 , wherein the environment parameter is determined from at least one of a driving dynamic variable sensed via a sensor and at least one other parameter.

4. The method according to claim 3 , wherein a vehicle speed related parameter is processed as the driving dynamic variable.

5. The method according to claim 4 , wherein the vehicle speed related variable is one of an undershooting and overshooting of a predefined speed.

6. The method according to claim 3 , wherein a distance related variable between the vehicle and an object is processed as the driving dynamic variable.

7. The method according to claim 6 , wherein the distance related variable is one of an undershooting and overshooting of a predefined distance between the vehicle and the object.

8. The method according to claim 3 , wherein a current position of the vehicle is processed as the other parameter.

9. The method according to claim 3 , wherein at least one of a topology and a current weather condition is processed as the at least one other parameter.

10. The method according to claim 3 , wherein a user selected parameter is processed as the other parameter.

11. The method according to claim 3 , further comprising the acts of:

determining entropy values of the visual image and the infrared image;

comparing the entropy values with a predefined entropy value; and

determining whether the visual image, the infrared image, and/or both the visual and infrared images, is to be blanked-out based on results of the comparing act.

12. The method according to claim 1 , wherein the interrupting act further comprises the act of ceasing the fusing act based upon a time hysteresis.

13. A system for visualizing surroundings of a vehicle, comprising:

a visual camera providing a visual image, containing digital data of the surroundings, the visual image showing visually perceptible objects;

an infrared camera providing an infrared image, containing digital data of the surroundings, the infrared image showing infrared radiation emitted by the visually perceptible objects and/or other objects, wherein the visual camera and the infrared camera form a camera system;

a calibration unit configured to calibrate the camera system with respect to a fixed distance corresponding to one of a close range and a far range;

an image processing unit for processing the visual image and the infrared image, the image processing unit fusing the visual image and the infrared image into a target image;

an image display unit which displays the target image from the image processing unit; and

wherein the image processing unit is operatively configured to automatically interrupt the fusing of the visual image and the infrared image when an orientation error exceeds a threshold which is a function of an environment parameter, wherein the orientation error is a parallax error owing to the offset optical axes of the visual camera and the infrared camera, respectively, said orientation error occurring in the close range if the fixed distance to which the camera system is calibrated is the far range, and occurring in the far range if the fixed distance to which the camera is calibrated is the close range.

14. The system according to claim 13 , further comprising at least one sensor, coupled to the image processing unit, for supplying a driving dynamic variable utilized as the environment parameter.

15. The system according to claim 14 , wherein an additional parameter is supplied to the image processing unit for utilization in interrupting the fusing of the visual image and the infrared image.

16. The system according to claim 13 , wherein the image processing unit is operatively configured to determine the environment parameter based on a driving dynamic variable and/or an additional parameter.

17. A method of operating an image fusion system utilized for visualizing surroundings of a vehicle, the image fusion system operating to fuse a visual image obtained by a visual camera and containing digital data of the surroundings showing visually perceptible objects and an infrared image obtained by an infrared camera and containing digital data of the surroundings showing infrared radiation emitted by the visually perceptible objects and other objects, wherein the visual camera and the infrared camera form a camera system, the operating method comprising the acts of:

calibrating the camera system with respect to a fixed distance corresponding to one of a close range and a far range

receiving at least one environment parameter of the vehicle; and

interrupting the fusion of the visual image and the infrared image automatically when an orientation error exceeds a threshold which is a function of the at least one environment parameter, such that either only the visual image or the infrared image, or neither image, is displayed to a user of the vehicle, wherein the orientation error is a parallax error owing to the offset optical axes of cameras used to obtain the visual image and the infrared image, respectively, said orientation error occurring in the close range if the fixed distance to which the camera system is calibrated is the far range, and occurring in the far range if the fixed distance to which the camera is calibrated is the close range.

18. The operating method according to claim 17 , wherein the interrupting is performed by blanking-out all of the digital data of the respective image or images.

19. The method according to claim 17 , wherein the at least one environment parameter is one of a vehicle speed related variable and a vehicle distance related variable.