Laser Scanner Point Cloud Alignment Using Reflection Prisms
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Solution Overview
Problem
Existing surveying methods using laser scanners require known points in the scanning range to connect point cloud data from multiple scans, which is time-consuming and inefficient.
Innovation Solution
A surveying method that performs first and second laser scans of reflection prisms at unknown positions, extracts their relative positions from point cloud data, and aligns the data using these prisms to create connection data without requiring known points in the scanning range.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If known points are included in the scanning range to connect point cloud data from multiple scans, then measurement precision is improved, but loss of time increases due to the need to survey and set known points before each scan
Solution Approach 1:
The patent introduces reflection prisms as intermediary objects with known relative positions to mediate the connection between multiple point cloud scans. These prisms serve as common reference points that enable accurate data fusion without requiring surveyors to manually measure and establish known points in the absolute coordinate system for each scan, thereby resolving the contradiction between measurement precision and time loss
Solution Approach 2:
The patent applies preliminary action by pre-establishing the relative positional relationships among reflection prisms through the first laser scan, and then using these pre-extracted relative positions as reference for subsequent scans. This eliminates the need for real-time surveying and setting of known points before each scan, reducing time loss while maintaining connection accuracy
2Reliability
If known points are required in each scan range, then reliability of data connection is improved, but ease of operation deteriorates due to complex surveying procedures
Solution Approach 1:
The system performs self-service by automatically extracting relative positions of reflection prisms from the point cloud data obtained during the first laser scan, and then using these automatically derived positions for aligning subsequent scans. This eliminates the need for manual surveying and setting operations, significantly improving ease of operation while maintaining reliable data connection through the use of reflection prisms as stable reference points
3Ease of operation
If multiple laser scans are performed without known points, then ease of operation is improved, but measurement precision deteriorates due to inability to accurately connect point cloud data
Solution Approach 1:
Reflection prisms serve as intermediary reference objects that enable accurate connection of multiple point cloud scans without requiring manual surveying. The prisms are distributed across the survey area and provide stable, detectable reference points that maintain measurement precision while allowing operations to proceed without known points in the absolute coordinate system
Solution Approach 2:
The patent segments the survey area into multiple scan ranges that can be independently processed, with reflection prisms serving as common reference points across segments. This segmentation allows each scan to be performed independently without requiring known points, while the relative positions of prisms enable accurate connection of all segments through computational alignment
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 the acquisition of point cloud data with high accuracy and reduced operational effort by eliminating the need for known points in each scan, allowing for efficient data collection over wide survey areas.
Implementation Method 1
a measurement method for obtaining point cloud data of a space by combining point clouds using a laser scanner
Implementation Method 2
first laser scan of multiple reflection prisms at unknown positions and a survey target range
Implementation Method 3
extraction of bright spots of light reflected from the optical reflection targets within laser scan data
Data Source
AI summary
The present disclosure allows the acquisition of point cloud data by multiple laser scans with a simple operation without including a known point in a scanning range for each scan. A surveying method using a laser scanner includes: first laser scan of multiple reflection prisms at unknown positions and a survey target range; second laser scan of a range including the multiple reflection prisms that were subjected to the first laser scan and that is different from the range of the first laser scan; extraction of relative positions of the reflection prisms from first point cloud data acquired by the first laser scan and second point cloud data acquired by the second laser scan; and creation of connection data by connecting the first point cloud data and the second point cloud data.