Optoelectronic Sensor Threshold Sampling for Memory Reduction
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Solution Overview
Problem
Conventional optoelectronic sensors using the time-of-flight method face challenges in efficiently storing and processing data for accurate distance measurement, leading to high memory requirements and costs due to the need for powerful FPGAs and complex data handling.
Innovation Solution
The approach involves sampling received signals with both high and low thresholds, storing only derived variables and threshold crossings when the high threshold is exceeded, and using a control and evaluation unit to dynamically adapt the high threshold based on the distance and noise levels, thereby reducing data storage needs and using less expensive components.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If pulse averaging methods are used to improve signal-to-noise ratio, then measurement precision is improved, but memory requirements increase linearly with the number of individual measurements
Solution Approach 1:
The patent extracts only the essential information from received signals - specifically threshold crossing events - rather than storing complete signal waveforms. By identifying and storing only the time points where signals cross predefined thresholds, the system maintains measurement precision while dramatically reducing memory requirements from storing full waveforms to storing discrete event timestamps.
Solution Approach 2:
The patent changes the representation parameter of received signals from continuous waveform data to discrete threshold crossing events. By transforming the data from storing amplitude-time continuous functions to storing discrete time points where thresholds are crossed, the system achieves compression while preserving the essential temporal information needed for distance measurement.
2Measurement precision
If a finer time sampling grid is used to achieve more precise distance measurements, then measurement precision is improved, but data volume increases
Solution Approach 1:
The patent extracts only the critical temporal information - threshold crossing events - from the sampled signals. Instead of storing all sampled values from a fine time grid, the system identifies and stores only the specific time points where signals cross thresholds, thereby maintaining precise time-of-flight measurement capability while reducing data volume by eliminating redundant sampling points that do not contain threshold crossing information.
3Measurement precision
If multi-threshold sampling with amplitude resolution is used, then measurement precision is improved, but data volume increases significantly
Solution Approach 1:
The patent segments the amplitude range into multiple thresholds and processes each threshold independently to detect crossing events. By dividing the signal analysis into multiple threshold levels and recording crossing events for each, the system achieves amplitude resolution information while maintaining data efficiency through event-based recording rather than storing complete multi-level sampled waveforms.
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 method significantly reduces memory requirements, allowing for more precise and extended range measurements with simpler, less expensive hardware, and enables the evaluation of multiple measuring beams with the same electronics, while maintaining high precision and reliability.
Implementation Method 1
light pulses are repeatedly emitted by a light transmitter and received again by a light receiver
Data Source
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AI summary
An optoelectronic sensor (10) for detection and distance determination is described, comprising a light transmitter (12) for repeatedly emitting light pulses for each individual measurement, a light receiver (22) for generating a received signal from a light pulse remitted by the object (20), a first scanning unit (34) for scanning the received signal with a low threshold and a second scanning unit (36) for scanning the received signal with a high threshold, a memory (42) for storing sample values from the first scanning unit (34) and/or the second scanning unit (36) or quantities derived therefrom, and a control and evaluation unit (38, 40) which is designed toto determine a measured value for the light travel time from the sensor (10) to the object (20) after several individual measurements using the data stored in the memory (42) and furthermore to store sample values of the first sampling unit (34) or quantities derived therefrom in the memory (42) only if the second sampling unit (36) detects an exceedance of the high threshold for the same individual measurement.