Lidar Scanning Density Adjustment for Point Cloud Consistency
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Solution Overview
Problem
Lidar systems experience varying point cloud densities with distance, leading to inconsistencies in data analysis, particularly in detecting surface defects like cracks on buildings.
Innovation Solution
An optical sensing system with a three-dimensional scanner that dynamically adjusts scanning density based on distance to the measurement point or luminance of reflected light, using methods like direct time of flight or frequency modulated continuous wave, to maintain consistent point cloud density.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If a fixed scanning density is used in Lidar scanning, then the scanning process is simple and fast, but the point cloud density varies with distance causing inconsistency in data analysis
Solution Approach 1:
The patent implements dynamic scanning density adjustment by modifying the scanning control unit to real-time adjust scanning parameters based on measured distance. The scanning frequency or line spacing is dynamically changed according to distance to maintain consistent point cloud density across different ranges, transforming a static scanning system into an adaptive one that responds to varying target distances.
Solution Approach 2:
The patent changes scanning parameters (such as scanning frequency, line spacing, or angular resolution) based on distance measurements. When the target is farther away, the system increases scanning density by reducing line spacing or increasing scans per second, while closer targets use lower density. This parameter adaptation resolves the contradiction between measurement precision and device complexity.
2Measurement precision
If scanning density is increased for distant targets to maintain point cloud density, then measurement precision improves, but scanning time and data processing load increase
Solution Approach 1:
The patent applies different scanning densities to different spatial regions based on distance. Distant regions receive higher scanning density while near regions use lower density. This localized adaptation ensures that each region contributes equally to the overall point cloud quality without uniformly increasing scanning time across the entire field of view, thus resolving the time penalty.
Solution Approach 2:
The system dynamically adjusts scanning density in real-time based on detected distance variations. By using feedback from distance measurements to modulate scanning parameters on-the-fly, the system optimizes point cloud density consistency while adapting scanning time to actual scene requirements rather than using a conservative fixed high-density mode throughout.
3Productivity
If scanning density is decreased for near targets to reduce scanning time, then productivity improves, but point cloud density becomes inconsistent
Solution Approach 1:
The patent implements spatially varying scanning density where near targets use lower scanning density and distant targets use higher density. This local optimization allows the system to reduce scanning time for close objects while maintaining adequate point cloud density for far objects, achieving overall productivity improvement without sacrificing measurement precision consistency across the scene.
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
This approach ensures consistent point cloud density across varying distances, enhancing the accuracy of defect detection and analysis by adjusting scanning parameters in real-time.
Implementation Method 1
measuring a distance to a distance measurement point by scanning the measurement target with laser light L1 and receiving reflected light L2
Implementation Method 2
receiving reflected light of the laser light
Data Source
AI summary
The optical sensing system includes a three-dimensional scanner and a scanning density determination means. The three-dimensional scanner measures a distance to a measurement target by scanning the measurement target with a laser light and receiving reflected light of the laser light. The scanning density determination means dynamically determines a scanning density based on a distance to a distance measurement point or luminance of the reflected light during scanning of the three-dimensional scanner so as to suppress variation in a point cloud density caused by a length of the distance to the distance measurement point.