Laser Distance Module Polarization Analysis Multiple Reflections
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Solution Overview
Problem
Current distance measurement technologies face challenges in accurately determining distances due to multiple reflections, especially in scenarios with rough or metallic surfaces, leading to artifacts and incorrect measurements, as they often fail to differentiate between single and multiple reflections effectively.
Innovation Solution
The method involves transmitting a laser signal in a defined polarization state, allowing the detection of polarization identifiers in the received signal to differentiate between single and multiple reflections, using Stokes parameters and polarization analysis to correct distance measurements.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If conventional distance measurement methods are used without polarization analysis, then the device complexity remains low, but measurement precision deteriorates due to inability to differentiate between single and multiple reflections
Solution Approach 1:
The patent applies parameter changes by utilizing the polarization state of the laser signal as an additional measurement parameter. By analyzing changes in polarization identifiers (Stokes parameters) between transmitted and received signals, the system can differentiate between single reflections and multiple reflections, thereby improving distance measurement accuracy without requiring complex hardware modifications
Solution Approach 2:
The patent uses polarization analysis as an intermediary mechanism to indirectly identify multiple reflections. Instead of directly detecting multiple reflection paths, the system uses polarization state changes as a mediator to infer the presence of multiple reflections and correct distance measurements accordingly
2Measurement precision
If polarization analysis is added to differentiate single and multiple reflections, then measurement precision improves, but device complexity increases due to additional processing requirements
Solution Approach 1:
The patent implements partial action by selectively applying polarization analysis only when multiple reflections are suspected or when measurement uncertainty exists. The system processes polarization identifiers to the extent necessary to identify and correct multiple reflection artifacts, avoiding unnecessary full polarization analysis in all measurement scenarios
Solution Approach 2:
The patent extracts only the relevant polarization identifiers (Stokes parameters) from the complete polarization state information. By focusing on specific polarization parameters that are most indicative of multiple reflections, the system reduces processing complexity while maintaining measurement precision
3Reliability
If polarization identifiers are used to identify multiple reflections, then reliability of distance measurement improves, but loss of information increases due to need to process additional signal characteristics
Solution Approach 1:
The patent performs preliminary action by pre-calculating and storing reference polarization states for different surface types and reflection scenarios. During actual measurement, the system compares received polarization identifiers against these pre-established references, reducing real-time processing requirements while maintaining high reliability in identifying multiple reflections
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 detection and correction of artifacts caused by multiple reflections, improving the accuracy of distance measurements by identifying and accounting for polarization changes in the received signal, thus enhancing measurement precision.
Implementation Method 1
transmitting unit (2) for sending a transmit signal, in particular a pulsed signal series
Implementation Method 2
wherein the transmit signal is sent and the received signal is acquired in such a way that a polarization identifier of the polarization state of the transmitted signal can be derived
Data Source
Figure 1a~1b
Figure 2a~2b
Figure 2c
AI summary
The present invention relates to a distance measurement method and an electronic laser distance measurement module, in particular for use in a handheld distance measuring device (1, 1', 1", 1''), laser scanner, profiler, laser tracker, or total station, for determining a distance to a target object, wherein a transmitting unit of the laser distance measurement module emits the transmit signal (20) with selected polarization states. The transmit signal (20) is emitted and the received signal is acquired in such a way that a polarization identifier of the polarization state of the transmit signal (20) is attached to the received signal, and an evaluation of the received signal is derived based on the polarization identifier in order to take multiple reflections into account when processing the received signal for determining the distance.