Laser Scanner Multi-Intensity Pulse Distance Measurement
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Solution Overview
Problem
Conventional distance-measuring laser scanners face challenges in achieving high measurement accuracy due to signal clipping and distortion, especially in environments with varying surface properties and distances, leading to increased measurement errors and reduced robustness.
Innovation Solution
The use of multiple transmitted light pulses of different intensities allows for precise determination of the time position of received pulses, achieving a high signal-to-noise ratio without overdriving signals, and utilizing these pulses for distance measurement and correction, reducing the need for complex electronics and correction tables.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If a transimpedance amplifier is used to handle large received signals, then the dynamic range is extended, but the signal is overdriven causing clipping and distortion
Solution Approach 1:
The received signal is divided into multiple segments corresponding to different transmitted light pulses with different intensities. By segmenting the signal processing into multiple intensity levels, the system can select appropriate segments based on signal strength to avoid overdriving while maintaining dynamic range coverage.
Solution Approach 2:
The system dynamically selects which transmitted light pulse intensity level to use for distance measurement based on the received signal characteristics. This dynamic adaptation allows the system to adjust to varying signal conditions without fixed amplifier settings, preventing clipping while covering the full dynamic range.
2Measurement precision
If the dynamic range is adapted to strong received signals to avoid clipping, then signal distortion is reduced, but weak received signals are poorly detected
Solution Approach 1:
Different transmitted light pulses have different intensities tailored to specific detection needs. Weak pulses are used for detecting low-reflectivity objects without overdriving, while strong pulses handle high-reflectivity objects. Each pulse intensity level has optimized local quality suited for its specific detection scenario.
Solution Approach 2:
Multiple transmitted light pulses with different intensities are emitted, using more action than a single pulse would provide. This partial/excessive approach ensures that at least one pulse intensity level is appropriate for the current signal conditions, guaranteeing reliable detection across all object types.
3Measurement precision
If correction tables are used to compensate for pulse shape distortion, then measurement accuracy is improved, but device complexity and production costs increase
Solution Approach 1:
The system uses itself to generate the correction data by emitting multiple light pulses and analyzing the received signal characteristics. The evaluation unit automatically determines which pulse intensity level provides accurate timing without external correction tables, making the system self-calibrating and eliminating complex correction infrastructure.
Solution Approach 2:
The system performs preliminary evaluation of received signal characteristics before final distance calculation. By analyzing signal quality metrics in advance, the system pre-determines the appropriate pulse intensity level to use, avoiding the need for complex real-time correction during the measurement process.
4Measurement precision
If multiple transmitted light pulses of different intensities are used, then measurement accuracy across dynamic range is improved, but the number of transmitted pulses increases
Solution Approach 1:
Multiple transmitted light pulses are emitted in a periodic sequence with different intensities. This periodic multi-intensity approach allows the system to gather information from multiple pulse levels efficiently, selecting the most appropriate pulse for distance measurement while maintaining high measurement speed through the structured periodic emission pattern.
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 high measurement accuracy across a wide dynamic range with minimal additional effort, improving robustness and reducing production costs, while maintaining accuracy across varying environmental conditions.
Implementation Method 1
A light beam generated by a laser periodically scans a surveillance area
Implementation Method 2
the distance of the object from the laser scanner is also determined from the travel time of light using the speed of light
Implementation Method 3
The light is remitted to objects in the surveillance area and evaluated in the scanner
Data Source
Figure 1~2
Figure 3a~3c
AI summary
The scanner (10) has a light transmitter (12) i.e. laser, transmitting light rays (14) with light pulses. Light deflecting units (16a, 16b) periodically scan a surveillance region (18) with the pulses. A light receiver (24) produces receiving signals from the pulses emitted by an object. An evaluating unit (34) determines a distance of the object from running time of the pulses, and electronically controls the transmitter in different ways so that a weak light pulse and a strong light pulse are transmitted. The weak light pulse is weaker than the strong light pulse around magnitudes. An independent claim is also included for a method for detecting objects in a surveillance region.