Method and device for camera-based determination of a distance of a moving object in the surroundings of a motor vehicle

A device for camera-based determination of a distance of a moving object in the surroundings of a motor vehicle, comprising:

• a camera for capturing the surroundings;
• and
• an evaluation circuit;
• wherein the camera is configured to capture a first surroundings image of the surroundings at a first time and a second surroundings image of the surroundings at a subsequent second time;
• and wherein the evaluation circuit is configured:
• to identify the moving object in the captured surroundings images;
• to identify at least one stationary object in the captured surroundings images and to select said stationary object in the captured surroundings images according to a distinguished geometric relationship relative to the moving object in the first surroundings image;
• to determine an image size ratio between an image size of the moving object and an image size of the stationary object in the first surroundings image;
• to determine an image size of the stationary object in the second surroundings image, wherein determining the image size ratio comprises determining a first number of image elements in the first surroundings image for a height and/or a width of the moving object and a second number of image elements in the first surroundings image for a height and/or a width of the stationary object and determining the image size ratio based on the first number of image elements and the second number of image elements;
• to determine distances of the stationary object at the first time and at the second time and an object size of the stationary object on the basis of the determined image sizes of the stationary object and a vehicle speed;
• and
• to determine distances of the moving object at the first time and at the second time on the basis of the determined image size ratio, the determined distances and the determined object size of the stationary object.

A method for camera-based determination of a distance of a moving object in the surroundings of a motor vehicle, comprising:

• capturing a first surroundings image of the surroundings at a first time and a second surroundings image of the surroundings at a subsequent second time using a camera;
• identifying the moving object in the captured surroundings images;
• identifying at least one stationary object in the captured surroundings images and selecting the at least one stationary object according to a distinguished geometric relationship relative to the moving object in the first surroundings image;
• determining an image size ratio between an image size of the moving object and an image size of the stationary object in the first surroundings image;
• determining an image size of the stationary object in the second surroundings image;
• determining distances of the stationary object at the first time and at the second time and an object size of the stationary object on the basis of the determined image sizes of the stationary object and a vehicle speed;
• and
• determining distances of the moving object at the first time and at the second time on the basis of the determined image size ratio, the determined distances and the determined object size of the stationary object;
• determining and providing a relative speed of the moving object with respect to the motor vehicle on the basis of the determined distances of the moving object and a time difference between the first time and the second time;
• and
• determining and providing an absolute speed of the moving object, wherein for this purpose the determined relative speed and a vehicle speed of the motor vehicle are added together.