Laser Scanner ToF Correction for Overlapping Reflected Pulses
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Solution Overview
Problem
Laser scanner apparatuses face challenges in accurately determining Time-of-Flight (ToF) measurements due to overlapping reflected pulses from closely spaced objects, which complicates waveform analysis and can lead to inaccurate distance determinations.
Innovation Solution
The apparatus classifies reflected pulses as either single or merged pulses based on pulse attributes, using different ToF algorithms for each type. For single pulses, it determines ToF based on rising and falling edges, while for merged pulses, it compensates for wider pulse widths by adjusting the ToF calculation with a programmed offset.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If a single ToF algorithm is used for all reflected pulses, then the device complexity is reduced, but the measurement precision deteriorates due to inaccurate distance determination for merged pulses
Solution Approach 1:
The patent segments the ToF measurement process by dividing reflected pulses into two categories: single pulses and merged pulses. Different ToF algorithms are assigned to each category based on pulse classification. This segmentation allows each algorithm to be optimized for its specific pulse type, improving measurement precision while maintaining manageable system complexity through systematic categorization.
2Productivity
If the apparatus monitors for reflected pulses at high measurement speeds, then the productivity is improved, but the difficulty of detecting and measuring increases due to waveform complexities
Solution Approach 1:
The patent applies preliminary action by classifying reflected pulses as single or merged pulses before performing ToF calculations. This preliminary classification step simplifies subsequent waveform analysis by pre-identifying the appropriate analysis method, thereby reducing the difficulty of detecting and measuring waveform characteristics at high measurement speeds.
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 enhances the accuracy of distance determinations in scenarios with overlapping reflections, ensuring reliable and precise object detection.
Implementation Method 1
A laser scanner apparatus emits a laser pulse
Implementation Method 2
detects one or more 'reflection' pulses, as backscattered from one or more objects
Implementation Method 3
a photodetector that outputs a photodetector signal that varies responsive to backscattered light impinging on the photodetector
Implementation Method 4
Determining the temporal offset—the timewise location—of such signal pulses in relation to the transmission time of the outgoing laser pulse allows the apparatus to estimate object distance, according to ToF calculations
Data Source
AI summary
A laser scanner apparatus emits a laser pulse and monitors for pulse reflections, with the relative timing of a reflected pulse detected by the apparatus being translated into an object distance according to Time-of-Flight (ToF) measurements performed by the apparatus. According to an example configurations or an example method of operation, the apparatus adjusts its ToF determination for reflected pulses that are characterized as merged pulses formed by two or more overlapping reflected pulses. Among other advantages, the adjusted ToF determination yields a more accurate distance determination with respect to the earliest-arriving one(s) among the overlapping reflected pulses.