Laser Scanning Device With Overlapping Scan Compartments
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Solution Overview
Problem
Current laser scanning devices face limitations in simultaneously achieving high sensitivity and transmission power for both weakly reflective and highly reflective scanning points, as well as precise distance measurements across varying distances, due to conflicting requirements in pulse width, divergence, and noise handling, which affects the creation of accurate 3D point clouds.
Innovation Solution
The device employs multiple scanning units with adjustable pulse repetition rates, angular velocity profiles, and pivot angles to overlap scanning compartments, allowing for simultaneous measurement of scanning points with different properties using varying sensitivity, transmission power, pulse widths, and beam divergences, enabling precise and multi-target capable scanning.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If high sensitivity and high transmission power are used to measure weakly reflecting or distant scanning points, then measurement capability for weakly reflecting points is improved, but the laser receiver saturates at strongly reflecting or near scanning points and cannot detect subsequent pulses
Solution Approach 1:
The patent divides the measurement task into multiple scanning units, each with different sensitivity and transmission power characteristics. This segmentation allows the system to measure both weakly reflecting and strongly reflecting points simultaneously without receiver saturation, as each unit is optimized for specific reflection conditions.
Solution Approach 2:
Different scanning units are assigned different local qualities (sensitivity levels and transmission powers) according to the specific requirements of different scanning points. Units with higher sensitivity are used for distant or weakly reflecting points, while units with lower sensitivity are used for near or strongly reflecting points, optimizing measurement for each local condition.
2Measurement precision
If shorter pulse widths are used to accurately determine propagation time and distinguish multiple target reflections, then distance measurement accuracy is improved, but received signals from weakly reflecting or distant points are lost in receiver noise
Solution Approach 1:
Different scanning units employ different pulse widths according to their specific measurement conditions. Units measuring distant or weakly reflecting points use longer pulse widths to ensure sufficient signal energy, while units measuring near or strongly reflecting points use shorter pulse widths for accurate time-of-flight measurement and multiple target separation.
3Adaptability or versatility
If larger sampling points are used to enable multi-target capability in inhomogeneous environments, then ability to measure multiple targets simultaneously is improved, but scan direction determination becomes imprecise
Solution Approach 1:
The patent segments the measurement function across multiple scanning units with different beam divergences. Some units use larger beam divergences to achieve multi-target capability in inhomogeneous environments, while other units use smaller beam divergences for precise scan direction determination, allowing both requirements to be satisfied simultaneously.
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 enables the creation of highly accurate and informative 3D point clouds by allowing multiple scanning of the same points with different scanning units, improving signal-to-noise ratio and multi-target capability, thereby enhancing the precision and range of laser scanning.
Implementation Method 1
a laser transmitter for emitting a pulse train of laser pulses
Implementation Method 2
the associated laser pulses reflected from first scanning points of the environment
Implementation Method 3
which they traverse with a predeterminable angular velocity profile
Implementation Method 4
measuring the time of flight of the associated laser pulses reflected from first scanning points of the environment
Data Source
Figure 1~2
Figure 3a~3d
Figure 4~5
AI summary
Device (1) for measuring an environment (2), comprising a first and at least one further scan unit (6k), each for emitting a pulse train (4k) of laser pulses (5k,n) over successive deflection periods (APk,p) with a pulse repetition rate (PRR), wherein the laser pulses (5k,n) falling within each deflection period (APk,p) form a scan fan (8k) per deflection period (APk,p), which they traverse with a predefinable angular velocity profile (ω), and for receiving the associated laser pulses (5k,n) reflected from scanning points (Pk,n), wherein all scan fans (8k) overlap when viewed in the direction of one of the scan axes (7k), and a control device (29) connected to the at least one further scan unit (6k), which is configured toto pivot the scan compartments (8k) of each additional scan unit (6k) relative to the scan compartments (8k-1) of an adjacent scan unit (6k-1) by a swivel angle (λk,k-1) dependent on the pulse repetition rate (PRR) and the angular velocity profile (ω) such that their scanning points (Pk,n) coincide.