Laser Range Finder Vibration Compensation via Polarization Feedback
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Solution Overview
Problem
Laser range finders face issues with accurate obstacle detection due to vibrations causing erroneous detection of road surfaces as obstacles and failure to detect obstacles when the light projection direction is swung upward, leading to incorrect positioning and distance measurement.
Innovation Solution
A control apparatus and method that includes an object detection unit for projecting light and detecting reflections, a movable region normal detection unit to adjust the light projection direction orthogonally to the normal plane, and an environment mapping unit to generate accurate maps, utilizing a polarization camera to identify the normal direction of surfaces and correct light projection angles.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If the light projection direction of the laser range finder is rotated in a horizontal direction to detect obstacles, then the detection range is improved, but vibration of the moving body causes the light projection direction to swing up and down, leading to erroneous detection of road surface as obstacles or failure to detect actual obstacles
Solution Approach 1:
The system uses a polarization camera to detect the normal direction of the road surface and feeds this information back to adjust the light projection direction of the laser range finder. This feedback mechanism compensates for vibrations by continuously aligning the light projection direction to be orthogonal to the detected road surface normal, thereby maintaining reliable obstacle detection despite body movements.
Solution Approach 2:
The system changes the parameter of light projection direction based on the detected road surface normal direction. By dynamically adjusting the projection angle to maintain orthogonality with the road surface normal, the system adapts to vibration-induced position changes while preserving accurate obstacle detection capability.
2Measurement precision
If the light projection direction is swung upward to avoid detecting road surface as obstacles, then false positives are reduced, but obstacles on the road surface may no longer be detected
Solution Approach 1:
The system dynamically adjusts the light projection direction based on real-time road surface normal detection rather than using a fixed upward swing angle. This dynamic adaptation allows the system to maintain optimal detection coverage by aligning the projection direction orthogonally to the actual road surface orientation, ensuring both false positive reduction and complete obstacle detection.
3Device complexity
If the light projection direction is fixed in a horizontal direction, then the system structure is simple, but vibration causes the projection direction to deviate from the intended horizontal plane
Solution Approach 1:
The system replaces complex mechanical vibration compensation mechanisms with an optical sensing approach using a polarization camera to detect road surface normals. This substitution achieves precise projection direction control through optical field measurement and computational adjustment rather than mechanical stabilization, maintaining simplicity while improving precision.
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
Enables precise obstacle detection and generation of accurate environment maps by maintaining the light projection direction parallel to the road surface, reducing erroneous detections and ensuring obstacles are correctly identified.
Implementation Method 1
detects a direction and a distance in which the light is reflected, according to a difference time between a time of light projection and a time of light reception
Implementation Method 2
A polarization camera that captures polarized images with a plurality of polarization directions
Implementation Method 3
the object detection unit controls a light projection direction of light so as to change a direction along a plane orthogonal to the normal direction
Data Source
AI summary
A laser range finder projects light while changing a direction in a horizontal direction at a predetermined angle with respect to a vertical direction to also receive reflected light of the light, and detects a direction and a distance in which the light is reflected from an obstacle or the like, according to a difference time between a time of light projection and a time of light reception. A normal direction of a flat plane forming a road surface is detected on the basis of a polarized image. The laser range finder projects light such that the light has a predetermined angle with respect to the vertical direction so as to be orthogonal to the normal direction of the flat plane forming the road surface. The laser range finder can be applied to in-vehicle systems.