Laser Scanner Threshold Segmentation for Flat Object Measurement
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Solution Overview
Problem
Laser scanners face challenges in reliably measuring flat objects due to noise-induced high threshold values, which hinder accurate detection of flat objects in applications like parcel and letter sorting.
Innovation Solution
Determine separate threshold values for different ranges of measurement points based on quality criteria such as statistical noise, angle of incidence, and measured distance, allowing for regionally lower threshold values to improve measurement accuracy.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a high threshold value is used to filter noise in laser scanner measurements, then measurement reliability is improved, but the ability to measure flat objects deteriorates
Solution Approach 1:
The patent applies local quality by determining separate threshold values for different ranges of measurement points instead of using a single uniform threshold. The evaluation unit divides the measurement range into multiple ranges and assigns specific threshold values to each range based on local noise characteristics and quality criteria, allowing flat objects to be measured accurately in ranges where lower thresholds are applied while maintaining reliability in ranges with higher noise.
2Device complexity
If a single threshold value is used for all measurement points, then device complexity is reduced, but measurement precision for different object types deteriorates
Solution Approach 1:
The patent applies segmentation by dividing the measurement points into multiple ranges and determining separate threshold values for each range. The evaluation unit segments the measurement data based on position or other criteria and applies different thresholding strategies to each segment, improving overall measurement precision while keeping the complexity manageable through automated range determination and threshold calculation.
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 reliable and stable measurement of flat objects by using lower threshold values specific to each measurement point, enhancing the accuracy of laser scanner measurements.
Implementation Method 1
a light transmitter for transmitting light signals, a light deflection unit (formed, for example, by a rotating mirror) for the periodic deflection into a detection zone of the light signals transmitted by the light transmitter and comprises a light receiver for receiving light reflected back by an object located in the detection zone
Implementation Method 2
The distance is calculated by the laser scanner for this purpose e.g. by means of a transmit time measurement of the light signal at the respective measurement point or at a phase shift of a modulated signal caused by the transit time
Data Source
AI summary
A method of measuring an object by means of at least one first laser scanner is described which detects measured values for a plurality of measurement points, wherein only measured values which lie above a predefined threshold value are used for measuring the object. The method is characterized in that threshold values are determined separately for at least two ranges of measurement points of the laser scanner or laser scanners and the threshold value used for a measurement point is selected in dependence on a quality criterion.