Lidar System Prism Segmentation for 3D Point Cloud Density
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Solution Overview
Problem
Current lidar systems for 3D point cloud measurement are limited by their ability to achieve a broad field of view with high pixel density and fast refresh rates, which is crucial for autonomous navigation, especially in complex environments like highways, where they often compromise on either field of view or update rate, and struggle with seeing objects outside their limited range.
Innovation Solution
A lidar-based 3D point cloud measuring system with a rotary motor and multiple photon transmitter-detector pairs, allowing for a 360-degree horizontal field of view and high refresh rates, using a single detector shared among several lasers or dividing a single laser beam, and incorporating a proprietary filter to reject sunlight and dynamically adjust power for clear reflections.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Area of stationary object
If a single laser emitter/detector combination with a rotating mirror is used to achieve a broad field of view, then the field of view is expanded, but the point cloud density decreases and the system can only render 2-D point clouds
Solution Approach 1:
The patent divides the laser beam into multiple layers using a prism, creating multiple beams with different vertical angles. This segmentation allows the system to capture multiple layers of distance points simultaneously, increasing point cloud density while maintaining a broad field of view through the rotating mirror mechanism.
Solution Approach 2:
The patent transitions from 2-D to 3-D point cloud rendering by adding vertical layering through the prism. The multiple layers created by the prism provide the third dimension, enabling 3-D point cloud generation while the rotating mirror maintains the horizontal field of view coverage.
2Area of stationary object
If the laser path is altered using mirrors or prisms to achieve broader field of view, then the coverage area increases, but the point cloud becomes less dense
Solution Approach 1:
The prism segments the single laser beam into multiple layers, effectively multiplying the number of pixels captured in each horizontal scan line. This segmentation allows the system to maintain high pixel density across a broad coverage area by capturing multiple vertical layers simultaneously.
Solution Approach 2:
The rotating mirror continuously scans the multiple laser layers across the field of view, ensuring continuous coverage without gaps. This continuous scanning action maintains high pixel density by systematically capturing distance points across the entire coverage area in rapid succession.
3Quantity of substance
If multiple lasers and detectors are added to a rotating mirror unit to increase pixel density, then the number of pixels increases, but the image rotates and becomes unsuitable for sideways views
Solution Approach 1:
The patent creates a universal scanning system where a single rotating mirror assembly handles both horizontal scanning and vertical layering through the prism. This multi-functional design allows the system to maintain a fixed image orientation while achieving high pixel density, making it adaptable to various viewing directions including sideways views.
4Adaptability or versatility
If the entire instrument is actuated on a gimbal to provide 3-D point cloud coverage, then 3-D coverage is achieved, but the system complexity and size increase
Solution Approach 1:
The patent extracts the vertical scanning function from the mechanical gimbal system and replaces it with an optical prism that divides the laser beam into multiple vertical layers. This extraction eliminates the need for complex mechanical actuation while maintaining 3-D coverage capability, significantly reducing system complexity.
Solution Approach 2:
The patent replaces the mechanical gimbal system with an optical solution using a prism and rotating mirror. This substitution eliminates complex mechanical actuation mechanisms while achieving the same 3-D point cloud coverage, reducing device complexity and improving reliability.
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 provides a compact, rugged, and highly detailed 3D terrain map with high point cloud density and refresh rates, enabling accurate obstacle detection and navigation, capable of operating under various lighting and weather conditions, and can see through fog and heavy rain.
Implementation Method 1
the time it takes for that pulse of light to return to a detector mounted near the emitter is measured, and a distance can then be derived from that measurement with high accuracy
Implementation Method 2
the use of a pulse of light to measure distance is well known
Implementation Method 3
incorporating a proprietary filter to reject sunlight and dynamically adjust power for clear reflections
Data Source
AI summary
A lidar-based 3-D point cloud measuring system and method. An example system includes a base, a housing, a plurality of photon transmitters and photon detectors contained within the housing, a rotary motor that rotates the housing about the base, and a communication component that allows transmission of signals generated by the photon detectors to external components. The rotary component includes a rotary power coupling configured to provide power from an external source to the rotary motor, the photon transmitters, and the photon detectors. In another embodiment, the photon transmitters and detectors of each pair are held in a fixed relationship with each other. In yet another embodiment, a single detector is “shared” among several lasers by focusing several detection regions onto a single detector, or by using a single, large detector.