Optoelectronic Sensor Signal Evaluation for Interference Suppression
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Optoelectronic sensors face challenges in efficiently suppressing interference signals, leading to erroneous object detection signals due to noise and interference frequencies, which is critical in security applications where accuracy is paramount.
Innovation Solution
The method involves using different light signals with specific pulse structures and evaluation techniques to differentiate and suppress interference frequencies by analyzing the entire course of received signals, including pulse duration, height, and shape, rather than just counting individual pulses, allowing for effective noise suppression without prior identification of interference.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If light signals with several consecutive individual pulses are used to increase signal frequency for better interference filtering, then low interference frequencies can be filtered out more effectively, but the efficiency of filtering out interference signals is still insufficient for certain applications
Solution Approach 1:
The patent segments the received signal evaluation into multiple distinct evaluation methods: pulse counting for signals with multiple pulses, and evaluation of signal course characteristics (duration, height, shape) for single pulses. This segmentation allows each evaluation method to be optimized for specific signal types, thereby improving both filtering efficiency and detection reliability without requiring a single complex filtering system.
2Reliability
If the entire course of received signals including pulse duration, height and shape is evaluated, then spurious signals can be efficiently suppressed, but the device complexity increases
Solution Approach 1:
The patent implements dynamic signal evaluation by adapting the evaluation method based on the detected signal characteristics. The system dynamically switches between pulse counting mode (for multi-pulse signals) and course evaluation mode (for single-pulse signals), optimizing the evaluation approach for each specific signal type rather than using a fixed complex evaluation system for all signals.
Solution Approach 2:
The patent changes evaluation parameters based on signal characteristics: using pulse count as the primary parameter for multi-pulse signals, and switching to course parameters (duration, height, shape) for single-pulse signals. This parameter adaptation allows effective spurious signal suppression while keeping the evaluation system relatively simple by only activating complex evaluations when necessary.
3Measurement precision
If different light signals with different frequency ranges are used, then different interference frequencies can be suppressed, but the device complexity and signal processing requirements increase
Solution Approach 1:
The patent employs periodic transmission of different light signal types (multi-pulse sequences alternating with single pulses) to address different interference frequency ranges. This periodic alternation allows the system to suppress various interference frequencies without requiring simultaneous complex processing of multiple signal types, as each signal type is processed using its optimized evaluation method in turn.
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 significantly enhances noise suppression, reducing the likelihood of erroneous object detection signals by ensuring that only valid signals meet multiple conditions, thereby increasing the reliability of object detection in optoelectronic sensors.
Implementation Method 1
it can be determined whether light emitted by the light transmitter is reflected or remitted by an object located in the surveillance area to the light receiver
Implementation Method 2
the received light signals passing through a filter arrangement in the evaluation unit of the light receiver is permeable essentially only for spectral components of the pulse repetition frequency
Data Source
Figure 1~2b
Figure 3a~4
AI summary
The invention relates to a method for operating an optoelectronic sensor, particularly a light barrier, during which a light emitter emits light signals having a time interval toward a monitoring area, at least some of the light signals being comprised of a number of successive individual pulses. A light receiver receives the emitted light signals. An evaluating unit processes received signals generated from the received light signals and outputs an object determination signal according to the evaluation result. According to the inventive method, a number of light signals are emitted in a regular sequence, the courses of the respective received signals being evaluated in a different manner. The invention also relates to an optoelectronic sensor that is suited for carrying out the aforementioned method.