Optical Sensor Extraneous Light Detection via Time-Gated Evaluation
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Solution Overview
Problem
Existing optical sensors require a change in transmission mode to detect extraneous light, which complicates the reliable detection of objects and can lead to interference in surveillance systems.
Innovation Solution
The optical sensor employs a design where transmitted light pulses are emitted within predetermined expectation time intervals based on distance, allowing for the detection of extraneous light pulses outside these intervals without altering the transmitter's operation, using an extraneous light evaluation stage to differentiate between object and external light signals.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If the transmitter changes transmission mode to detect extraneous light, then extraneous light detection capability is improved, but device complexity and operational reliability deteriorate
Solution Approach 1:
The patent segments the detection function into two independent parts: the transmitter continues its normal object detection function while the extraneous light evaluation unit independently analyzes light pulses during transmission pauses. This segmentation allows extraneous light detection without requiring the transmitter to change its transmission mode, thus maintaining operational simplicity while improving detection capability.
Solution Approach 2:
The receiver serves multiple functions: it receives light pulses for object detection during active transmission periods and simultaneously detects extraneous light during transmission pauses. This multi-functionality eliminates the need for separate detection mechanisms, reducing device complexity while maintaining comprehensive surveillance capability.
2Measurement precision
If the transmitter changes transmission mode to detect extraneous light, then extraneous light detection capability is improved, but object detection reliability deteriorates
Solution Approach 1:
The system performs preliminary detection of extraneous light during transmission pauses before object detection occurs. By identifying and flagging extraneous light sources in advance, the system can compensate for or ignore these interference signals during subsequent object detection, thereby maintaining high object detection reliability while gaining extraneous light detection capability.
Solution Approach 2:
The extraneous light evaluation unit provides feedback information about detected extraneous light to the overall evaluation unit. This feedback mechanism allows the system to adjust its object detection algorithm to account for identified interference, maintaining accurate object detection even in the presence of extraneous light sources.
3Speed
If transmission pauses are used for extraneous light detection, then extraneous light detection speed is improved, but productivity deteriorates
Solution Approach 1:
The system maintains continuous surveillance by performing extraneous light detection during transmission pauses without interrupting the overall object detection process. The transmitter-receiver pairs continue their normal operation cycles, ensuring that object detection throughput is maintained while simultaneously monitoring for extraneous light sources during the otherwise idle pause periods.
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 enables reliable detection of pulsed extraneous light without modifying the transmitter's operation, ensuring high object detection reliability and minimizing interference, with signaling mechanisms to alert of critical extraneous light levels.
Implementation Method 1
a transmitter (2) emitting transmitted light pulses and a receiver (3), which are arranged at opposite edges of the surveillance area such that, when the surveillance area is clear, the transmitted light pulses from the transmitter (2) are directed to the receiver (3)
Implementation Method 2
a receiver (3)... The sensor also comprises an evaluation unit (9) in which an object detection signal is generated depending on the received signals from the receiver (3)
Data Source
Figure 1
Figure 2~3
AI summary
The invention relates to an optical sensor (1) for detecting objects within a monitoring area, comprising a transmitter (2) emitting light pulses and a receiver (3), which are arranged at opposite edges of the monitoring area such that, when the monitoring area is clear, the light pulses from the transmitter (2) are directed to the receiver (3), and an evaluation unit (9) in which an object detection signal is generated depending on the received signals from the receiver (3). The transmitter (2) emits the light pulses periodically within scan cycles, and the light pulses emitted by the transmitter (2) are received by the receiver (3) within predetermined expectation time intervals.An extraneous light evaluation stage is provided which evaluates light pulses registered at the receiver (3) within an observation period that is smaller than the scan cycle as extraneous light pulses if they are received outside the expected time interval.