Laser Scanner Horizontal Rotation Axis for Moving Target Precision
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Solution Overview
Problem
Conventional terrestrial laser scanners (TLS) have limitations in 3D measurement, including restricted vertical measurement due to fan angle limitations and imprecise horizontal movement detection, especially for targets like tree trunks in windy conditions, requiring repeated measurements and increased time and effort to reduce errors.
Innovation Solution
A TLS with a horizontal axis of rotation and a swivel drive that allows the scanning unit to pivot, enabling horizontal scanning at the speed of beam fanning rather than rotational movement, and flexible vertical adaptation, along with optional additional scanning compartments and a digital camera for enhanced precision and efficiency.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Area of stationary object
If the scanning unit rotates around a vertical axis to achieve 3D measurement, then the measurement coverage is improved, but the measurement precision of horizontally moving targets deteriorates due to slow rotational movement
Solution Approach 1:
The patent changes the rotation axis from vertical to horizontal, fundamentally altering the scanning geometry. This dimensional change allows the scanning fan to sweep horizontally at high speed while maintaining vertical coverage, resolving the contradiction between measurement coverage and precision for moving targets
Solution Approach 2:
The patent changes the rotation speed parameter by rotating the scanning unit around a horizontal axis rather than a vertical axis. This parameter change enables the scanning fan to cover the same area much faster, improving measurement precision for horizontally moving targets while maintaining full 3D measurement coverage
2Area of stationary object
If the fan angle is increased to improve vertical measurement coverage, then the measurement coverage is improved, but the device complexity increases due to complex intervention in deflecting optics
Solution Approach 1:
By changing the rotation axis from vertical to horizontal, the patent enables vertical measurement coverage to be achieved through the horizontal rotation of the scanning fan rather than by increasing the fan angle. This avoids the need for complex intervention in the deflecting optics while still achieving complete vertical coverage
Solution Approach 2:
The horizontal rotation of the scanning unit makes the scanning system multi-functional: it simultaneously achieves complete vertical coverage (equivalent to 360 degrees) and fast horizontal scanning, eliminating the need to increase the fan angle for improved vertical coverage
3Measurement precision
If repeated measurements are performed to reduce measurement errors, then the measurement precision is improved, but the measurement time increases
Solution Approach 1:
The patent changes the fundamental scanning parameter from vertical rotation to horizontal rotation, which enables the scanning fan to capture horizontally moving targets at high speed. This single measurement configuration achieves high precision without requiring repeated measurements, thereby reducing measurement time while maintaining or improving measurement 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
This configuration enhances measurement precision and efficiency, allowing for precise 3D measurement of horizontally moving targets without repetition and flexible vertical adjustment, while maintaining overall resolution and reducing measurement time and effort.
Implementation Method 1
The scanning unit 4, which is rotatably mounted relative to the tripod 3, emits modulated or pulsed laser beams 5
Implementation Method 2
which are fanned out by beam-deflecting optics of the scanning unit 4, e.g. rotating mirrors or prisms, over a fan angle φ around a scanning axis 6'
Implementation Method 3
If an emitted laser beam 5 strikes a target in the environment 1, e.g., a tree trunk 10 (see point of impact 11), it is reflected therefrom and the reflected laser beam 5* is received in the scanning unit 4
Implementation Method 4
In an evaluation unit connected to the scanning unit 4 and the rotary drive 12', the received laser beams 5* are evaluated according to their emission direction and their travel time
Implementation Method 5
a rotary drive 12' which rotates the scanning unit 4 and thus the scanning fan 7' through a rotation angle δ' around a vertical rotation axis 13'
Implementation Method 6
a pivot drive which is connected to the evaluation unit and is designed to pivot the scan unit through a predetermined pivot angle about a vertical pivot axis relative to the tripod
Data Source
Figure 1
Figure 2
Figure 3a~3c
AI summary
Laser scanner (1) for 3D measurement of an environment (1) using a time-of-flight laser method, comprising a tripod (3) for setting up in the environment (1), a scan unit (4) rotatably mounted on the tripod (3), which emits a largely flat scan fan (7) of laser beams (5) fanned out about a scan axis (6) and receives laser beams (5*) reflected from targets (10) in the environment (1), a rotary drive (12) which rotates the scan unit (4) about a predetermined rotation angle (δ) about an axis of rotation (13) normal to the scan axis (6) and to a beam direction (R) lying within the scan fan (7) relative to the tripod (3), an evaluation unit connected to the scan unit (4) and the rotary drive (12) for evaluating the received laser beams (5*), wherein the axis of rotation (13) is horizontal when the tripod (3) is set up in the environment (1).