Triangulation Light Sensor Adaptive Thresholding
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Solution Overview
Problem
Triangulation light sensors face challenges in reliably detecting objects on a conveying path due to fluctuations in the distance between the sensor and the background, leading to false positive and false negative object detection signals when the distance change is significant compared to the object height, especially with flat objects and mechanical fluctuations in the conveying path.
Innovation Solution
The evaluation unit dynamically adapts the distance threshold value by replacing it with a new value based on current distance measurements, using predefined hysteresis values to account for vertical fluctuations, and employs multiple light sources to ensure accurate detection by verifying distance consistency across multiple points of incidence.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a fixed distance threshold value is used for object detection, then the device structure is simple, but false detection occurs when the distance between the sensor and conveying path fluctuates
Solution Approach 1:
The system performs self-calibration by automatically adapting the distance threshold value based on background distance measurements. The evaluation unit continuously monitors the conveying path background and adjusts the threshold without external intervention, enabling the system to compensate for mechanical fluctuations and maintain reliable detection under varying conditions.
2Measurement precision
If multiple light sources are used to verify distance consistency, then measurement precision is improved, but device complexity increases
Solution Approach 1:
Multiple light sources create multiple light spots on the light receiver, providing redundant measurements of the same distance. By comparing the positions of these replicated light spots, the system verifies measurement consistency and eliminates false detections caused by background fluctuations, thereby improving measurement precision through redundancy.
3Reliability
If the distance threshold is dynamically adapted, then false positive and false negative signals are reduced, but the processing time and complexity increase
Solution Approach 1:
The system performs preliminary background scanning to determine the distance to the conveying path before object detection begins. This advance measurement allows the evaluation unit to pre-adapt the distance threshold value, so that when objects are detected, the threshold is already optimized for current conditions, reducing false signals without adding significant processing delay.
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 detection security by reducing false signals and ensuring reliable object recognition even with changes in the conveying path's vertical location, maintaining accurate object detection across varying conditions.
Implementation Method 1
The light receiver comprises at least one array of photosensitive reception elements
Implementation Method 2
The position of a light spot generated by remitted light on the light receiver in the triangulation direction changes in dependence on the distance between the triangulation light sensor and the remitting object
Data Source
AI summary
The present invention relates to a triangulation light sensor for the detection of objects on a conveying path having a light transmitter for transmitting transmitted light into a detection zone that extends over a part region of the conveying path, having a light receiver, a reception optics arranged in an optical path between the detection zone and the light receiver, and an evaluation unit that is configured for generating an object detection signal from the received signals.