Triangulation Sensor Scattered Light Compensation
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Solution Overview
Problem
Existing optoelectronic sensors face challenges in accurately detecting objects in surveillance spaces due to the influence of scattered light, such as from dirty windshields, which can lead to incorrect object detection, particularly in the close range, and require complex multi-channel processing to mitigate these issues.
Innovation Solution
The method employs a dual light source system with a primary transmission light diode and a diffuse light diode, where signals are weighted and processed using a multi-bit processing unit to differentiate between object reflections and scattered light, allowing for the adjustment of the diffuse light source's operating state based on threshold comparisons, thereby simplifying the processing to a few key steps.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If a dual light source system with diffuse light diode is used to compensate scattered light, then measurement precision is improved, but device complexity increases
Solution Approach 1:
The patent combines the diffuse light diode compensation function with the existing transmission light diode system into a unified signal processing pipeline. The signals from both light sources are processed through a single sampling stage and combined in a single adder, merging previously separate processing channels into one integrated flow that reduces overall system complexity while maintaining compensation capability.
Solution Approach 2:
The evaluation device is designed to handle signals from both transmission light diode and diffuse light diode through a universal processing path. The same sampling unit, weighting unit, and adder process signals regardless of which light source emitted them, creating a multi-functional system that can operate with either or both light sources without requiring separate dedicated processing channels.
2Measurement precision
If extensive multi-channel processing is used to mitigate scattered light effects, then measurement precision is improved, but device complexity increases
Solution Approach 1:
The patent extracts the essential compensation function from complex multi-channel processing and implements it through a simplified signal path. By taking out only the critical operations (single sampling, single weighting, single addition) needed to achieve scattered light compensation, the system maintains measurement precision while eliminating unnecessary processing complexity.
Solution Approach 2:
Instead of using multiple separate processing channels to handle scattered light compensation, the patent inverts the approach by using a single integrated processing channel that handles both transmission light and diffuse light signals together. This inversion from multi-channel to single-channel processing achieves the same compensation effect with reduced complexity.
3Measurement precision
If signals from near and far range are separately processed, then measurement precision is improved, but device complexity increases
Solution Approach 1:
The patent merges the processing of near-range and far-range signals into a single unified path. Both signal types pass through the same sampling unit, weighting unit, and adder, combining previously separate processing streams into one integrated flow that maintains range discrimination capability while reducing processing structure complexity.
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 effectively reduces the complexity of signal processing by limiting it to a single sampling and weighting stage, allowing for accurate object detection in the close range while minimizing errors from scattered light, without the need for extensive multi-channel processing.
Implementation Method 1
A transmission light source, in this case a light-emitting diode D 1, sends transmitted light pulses 20 into the surveillance space
Implementation Method 2
An object that may be in the light path reflects or remits such light that is imaged onto a receiver element arrangement by receiver optics
Implementation Method 3
a second light-emitting diode D2, which is designed to emit diffuse light and is also referred to here as a diffuse light-emitting diode D2
Implementation Method 4
A possible main application of such an arrangement is the detection of the presence of objects in the close range 52
Data Source
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AI summary
The invention relates to a method for determining the presence of an object in a monitoring space or a part thereof using an optoelectronic sensor operating on the triangulation principle. Light pulses from a first transmitting light source are sent towards the monitoring space. Expanded light pulses are then transmitted into the monitoring space by a second transmitting light source, with a time delay relative to the light pulses of the first transmitting light source. Light reflected or remitted by an object is received by a receiver element arrangement comprising a near-range section and a far-range section. Signals from receiver elements of the near-range section are multiplied with a first sign and signals from receiver elements of the far-range section with an opposite sign in a multiplication step and added in an addition step.The resulting summed signal is compared to a threshold value, and the comparison result signal, after multi-bit processing, is used as a presence signal. The signals received by the receiver arrangement during the first transmitted light pulses and the signals received during the light pulses of the second transmitting light source are weighted using weighting factors. The summed signal present after the addition step is sampled, and the sampled signal, after the weighting step, is compared to a threshold value. If a change occurs in the relationship between the presence signal after multi-bit processing and the comparison result signal, the operating state of the second transmitting light source is changed. The invention also relates to an optoelectronic sensor with which the method according to the invention can be carried out.