Vehicle Self-Positioning via Projected Light Patterns
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Solution Overview
Problem
Existing self-position calculating methods for vehicles face challenges in accurately determining vehicle position under adverse conditions, particularly when feature points are detected poorly due to factors like uneven road surfaces or reduced feature point visibility.
Innovation Solution
A self-position calculating apparatus and method that uses a light projector and camera to project a patterned light beam onto the road surface, with a CPU-controlled ECU processing images to extract feature points, calculate orientation and movement changes, and adjust for detection conditions, ensuring accurate positioning regardless of feature point quality.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If feature point detection is used to calculate vehicle movement, then vehicle position can be obtained, but accuracy deteriorates under bad detection conditions (uneven road surfaces, reduced visibility)
Solution Approach 1:
The patent introduces a light projector as an intermediary device that projects light patterns onto the road surface to create artificial feature points. This mediator ensures that feature points are always available for detection regardless of road surface conditions, thereby maintaining measurement precision and detection reliability simultaneously.
Solution Approach 2:
The system performs preliminary action by projecting light patterns onto the road surface before feature point detection is attempted. This pre-preparation of detectable features ensures that the camera can always find reference points for calculation, eliminating the reliability issue of feature point availability under various road conditions.
2Measurement precision
If additional sensors are added to improve detection accuracy, then measurement precision improves, but device complexity and cost increase
Solution Approach 1:
The light projector serves multiple functions: it illuminates the road surface for the camera to capture images, creates artificial feature points for movement calculation, and adapts to various road conditions. This multi-functionality allows the system to achieve high measurement precision using existing camera hardware without adding specialized sensors.
Solution Approach 2:
The system uses the vehicle's existing camera to detect the light patterns projected by the light projector. The camera serves itself by detecting the artificial features created by the projector, eliminating the need for additional dedicated sensors while maintaining high position estimation accuracy.
3Device complexity
If feature point detection relies on natural road features, then device complexity is low, but detection reliability deteriorates under adverse conditions
Solution Approach 1:
The light projector acts as an intermediary that transforms the road surface into a reliable detection target by projecting light patterns. This mediator ensures feature points are always detectable without complicating the overall system, as it only adds a single projector component while enabling the existing camera to function reliably under all conditions.
Solution Approach 2:
The system changes the parameter of feature point visibility by projecting light patterns that enhance contrast and create detectable features on the road surface. This parameter change ensures that feature points remain detectable under various lighting and road conditions while maintaining system simplicity.
Applied Scientific Principles
This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.
Function Achieved in This Case
The solution enables stable and accurate estimation of vehicle position by integrating movement changes and orientation angles, minimizing errors even under poor detection conditions, and reduces operational complexity and costs by not requiring additional sensors.
Implementation Method 1
a light projector (11) installed in the vehicle projects a patterned light beam (32a) on a road surface (31)
Implementation Method 2
a camera (12) installed in the vehicle obtains an image (38) of the road surface (31) around the vehicle, including an area onto which the patterned light beam (32a) is projected
Data Source
Figure 1
Figure 2
Figure 3(a)~3(b)
AI summary
A self-position calculating apparatus includes: a light projector 11 configured to project a patterned light beam 32a onto a road surface 31 around a vehicle; and a camera 12 configured to capture an image 38 of the road surface 31 around the vehicle including an area onto which the patterned light beam 32a is projected. The self-position calculating apparatus calculates an orientation angle of the vehicle 10 relative to the road surface 31 from a position of the patterned light beam on the image, and calculate an amount of change in orientation of the vehicle based on temporal changes in multiple feature points on the road surface which are detected from the image. The self-position calculating apparatus calculates current position and orientation angle of the vehicle by adding the amount of change in the orientation to initial position and orientation angle of the vehicle. If a condition under which the multiple feature points are detected does not satisfy a first criterion, the self-position calculating apparatus sets the current position of the vehicle at that time and the orientation angle of the vehicle calculated from the position of the patterned light beam at the initial position and orientation angle of the vehicle, and start to add the amount of change in the orientation to the initial position and orientation angle.