Vehicle Control Device Using Front Rear Cameras for Travel Distance Estimation
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Solution Overview
Problem
Existing methods for estimating a vehicle's position using wheel speed sensors face accuracy issues due to changes in tire circumferential length, and previous solutions like camera-based systems have limitations in reference distance, angular resolution, and detection accuracy, making it difficult to improve measurement precision.
Innovation Solution
A vehicle control device equipped with front and rear cameras that capture images of a characteristic object on the road surface, allowing for accurate calculation of wheel speed pulse distance by collating data from both cameras while ensuring a favorable reference distance and optimizing camera angles for enhanced angular resolution.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Device complexity
If a single camera is used to capture characteristic objects for measuring vehicle speed pulse distance, then the device complexity is reduced, but the measurement precision deteriorates due to limited reference distance and angular resolution
Solution Approach 1:
The patent divides the measurement task into two segments: the front camera captures the characteristic object at one position, and the rear camera captures the same object after the vehicle has traveled. This segmentation allows each camera to operate within its optimal angular resolution range while collectively providing a sufficient reference distance for accurate measurement.
Solution Approach 2:
The patent adds the spatial dimension by placing cameras at both front and rear of the vehicle, creating a longitudinal measurement baseline. This dimensional expansion transforms a single-point measurement into a multi-point measurement system, enabling accurate distance calculation through coordinate comparison between different camera positions.
2Measurement precision
If the reference distance is increased to improve measurement accuracy, then the measurement precision improves, but the time required for measurement increases as the vehicle must travel longer distances
Solution Approach 1:
The front camera performs preliminary capture of the characteristic object before the vehicle completes the full measurement distance. This allows the system to prepare measurement data in advance, and the rear camera completes the measurement as the vehicle passes, thereby reducing the actual time the vehicle must travel for measurement without sacrificing the necessary reference distance.
3Length of stationary object
If the camera captures the characteristic object at a long distance to increase reference distance, then the reference distance is sufficient, but the angular resolution deteriorates leading to poor detection accuracy
Solution Approach 1:
The patent applies local quality by having the front camera capture the characteristic object at a closer distance with higher angular resolution, while the rear camera captures the same object at a different position. This ensures that at least one camera captures the object within its optimal angular resolution range, maintaining detection accuracy while establishing sufficient reference distance through the coordinate difference between the two captures.
Data Source
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AI summary
The present invention enhances estimation accuracy of a travel distance to estimate a position of a host vehicle. A vehicle control device 1 includes front and rear cameras 8 and 9 and a measurement control unit 23. The front and rear cameras 8 and 9 are provided at front and rear of a vehicle 10 to acquire information on an external world. The measurement control unit 23 calculate a travel distance of the vehicle 10 during traveling of the vehicle 10 in a predetermined driving state based on the information of an identical characteristic object 30 acquired by the front camera 8 and the rear camera 9, the rear camera 9 acquiring the information of the identical characteristic object 30 after the front camera 8 acquires the information.