Vehicle Self-Positioning Using Reflectors and Wavelength Control
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Solution Overview
Problem
Existing techniques for estimating self-position, such as those using feature points from images, face accuracy issues in low-light conditions and high-luminance saturated regions, and can lead to misdetection due to direct light interference from oncoming vehicles.
Innovation Solution
A signal processing system that uses a light projection unit to project light at adjusted wavelengths, detects reflectors, and integrates orientation estimation results from reflector usage, image usage, and GPS/IMU data using Bayesian filtering to enhance self-position estimation accuracy.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If feature points are extracted from images to estimate self-position, then the system can recognize surrounding objects and estimate position, but the accuracy is reduced in dark conditions and high-luminance saturated regions
Solution Approach 1:
The patent uses a light projection unit to actively change the illumination parameter by projecting light at specific wavelengths onto reflectors in the environment. This transforms the passive imaging condition into an active controlled lighting scenario, ensuring sufficient light intensity for accurate feature extraction regardless of ambient lighting conditions.
Solution Approach 2:
The patent introduces reflectors as intermediary objects that receive projected light and reflect it back to the image pickup device. These reflectors act as mediators between the light source and the imaging system, enhancing the light signal in dark conditions while the saturation judgment unit filters out overly bright saturated regions that would compromise accuracy.
2Measurement precision
If feature points are extracted from images including high-luminance saturated pixel regions, then the system can process images quickly, but the accuracy of extracting feature points is reduced
Solution Approach 1:
The patent converts the harmful effect of high-luminance saturated regions into a beneficial filtering mechanism. The saturation judgment unit identifies and excludes these saturated pixel regions from feature point extraction, transforming what would be sources of error into a controlled filtering step that improves overall accuracy.
Solution Approach 2:
The patent extracts and removes the harmful saturated pixel regions from the image processing pipeline. By identifying and excluding these regions before feature point extraction, the system prevents them from degrading the accuracy of position estimation while maintaining efficient processing of valid image data.
3Adaptability or versatility
If the same light projection system is used by oncoming vehicles, then resource utilization is improved, but direct light from projectors leads to misdetection
Solution Approach 1:
The patent makes the light projection system dynamic by adjusting the wavelength of projected light based on detection results. When another vehicle's projector is detected, the system changes its operating wavelength to avoid interference, transforming a static conflicting scenario into a dynamic adaptive solution that maintains detection accuracy.
Solution Approach 2:
The patent implements feedback control where the detection results from the image pickup device are used to adjust the light projection parameters. When saturation or interference is detected, the system feeds this information back to modify the projection wavelength, creating a closed-loop control system that resolves conflicts with other vehicles' projectors.
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 system significantly improves self-position estimation accuracy by reducing interference and maintaining accuracy in low-light conditions and bright environments, while minimizing misdetection from oncoming vehicles.
Implementation Method 1
a light-receiving unit configured to receive light at a predetermined wavelength
Implementation Method 2
a wavelength adjustment unit configured to adjust a wavelength of light to be projected by the light projection unit
Implementation Method 3
integrates orientation estimation results from reflector usage, image usage, and GPS/IMU data using Bayesian filtering
Data Source
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AI summary
To improve estimation accuracy of a self-position. Light at a predetermined wavelength is projected. An image of a reflector with a reflectance higher than a predetermined reflectance is taken by receiving reflected light of the projected light reflected by the reflector. Own orientation is estimated on the basis of the taken image of the reflector. As a result, the self-position can be highly accurately estimated on the basis of the reflector even at night. The present disclosure can be applied to an on-board system.