Optical Sensor Using Three-Beam Segmentation for Precise Object Detection
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Solution Overview
Problem
Current optical sensors face challenges in precisely detecting objects moving laterally within their scanning range due to factors like conveyor belt speed fluctuations, object and background reflectance, distance from the sensor, and optics soiling, leading to inconsistent object position detection and erroneous switching.
Innovation Solution
The method involves generating three transmitted light beams that strike the object sequentially, with reflections detected as received light spots, and combining these signals to produce a comparison result that exceeds or falls below a threshold, ensuring precise object detection independent of object properties and environmental conditions.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If a single transmitted light beam is used for object detection, then the device complexity is low, but the measurement precision of object position deteriorates due to dependence on object properties and environmental conditions
Solution Approach 1:
The single transmitted light beam is divided into three separate transmitted light beams (first, second, and third beams) that are directed at different positions on the object. Each beam generates a separate receiving light spot on the receiver, allowing the system to detect multiple points on the object simultaneously. This segmentation enables more precise object position detection by comparing the relative positions of multiple receiving light spots, while the overall device structure remains relatively simple.
2Measurement precision
If the transmitted light beam is intensified to improve detection precision, then the measurement precision improves, but the object-generated harmful factors increase due to light scattering and background interference
Solution Approach 1:
Instead of using a single intense light beam that causes scattering and interference, the system uses three separate transmitted light beams with moderate intensity. Each beam is directed at a specific position on the object, and the corresponding receiving light spots are evaluated independently. This segmentation reduces the harmful effects of light scattering and background interference while maintaining detection precision through comparative analysis of the multiple light spots.
Solution Approach 2:
Each transmitted light beam is targeted at a specific local position on the object, and the corresponding receiving light spot is evaluated in relation to the others. This local quality approach allows the system to detect object position by comparing the relative positions of light spots from different locations, reducing the impact of global background interference and scattering effects.
3Productivity
If the sensor operates at high speed to match conveyor belt speed, then the productivity increases, but the measurement precision deteriorates due to reduced integration time and increased speed fluctuations
Solution Approach 1:
The system uses three transmitted light beams that are activated in a periodic or sequential manner, with each beam generating a receiving light spot that is evaluated in relation to the others. This periodic action allows the system to maintain high detection speed by quickly cycling through the three beams, while the comparative evaluation of the multiple light spots provides robust position detection that is less sensitive to speed fluctuations and integration time variations.
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 provides a highly precise and reproducible detection of object edges, reducing erroneous detections and allowing for precise control of subsequent processes, regardless of object properties or sensor settings, thereby improving the reliability and accuracy of object detection.
Implementation Method 1
The transmitted light is reflected by the conveyed object or, if the object is not present, by a background
Implementation Method 2
From the position of the center of gravity of a received light spot 118 on the receiver 114, the distance of the reflection, i.e., the object 120, can be deduced using triangulation
Data Source
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AI summary
The invention relates to a method and an optical sensor for improved, precise detection of an object conveyed relative to the sensor in a conveying direction. The method comprises the following steps: - Conveying the object through a detection area of the sensor and, during conveying, repeatedly performing the following steps at the current object position in the conveying direction: - Generating transmitted light consisting of three transmitted light beams arranged as follows:are designed so that when the object is conveyed, the object is first struck by the first, then by the second, and finally by the third transmitted light beam; - reflecting the transmitted light off the conveyed object or, if the object is not present, possibly off a background; - detecting the reflections of light associated with the transmitted light beams as receiving light spots and generating first, second, and third receiving signals associated with the transmitted light beams with at least one receiver; - combining the first and third receiving signals to form a combination result; - comparing the combination result with the second receiving signal or a value derived from the second receiving signal to form a comparison result; - outputting an object detection signal if the comparison result exceeds or falls below a threshold value.