Optoelectronic Sensor Edge Detection Using Multi-Point Triangulation
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Solution Overview
Problem
Existing optoelectronic sensors face challenges in reliably detecting object edges, especially for fast-moving, colorful, shiny, or reflective objects with narrow gaps, as conventional methods are either expensive, prone to errors, or not robust enough for accurate edge detection.
Innovation Solution
An optoelectronic sensor using at least two light transmitters with collimated transmission beams scans objects at multiple points, combining intensity and triangulation data to form a robust edge detection signal, which effectively distinguishes object edges from surfaces and background, even in challenging conditions.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If conventional light sensors or triangulation sensors are used, then the sensor structure is simple, but the edge detection reliability is poor for fast-moving objects with narrow gaps
Solution Approach 1:
The patent divides the detection task into multiple independent light transmitters (at least two) that scan different points on the object simultaneously. Each transmitter provides independent detection data, and the evaluation unit combines these segmented measurements to achieve reliable edge detection even for fast-moving objects with narrow gaps, without requiring complex mechanical structures
Solution Approach 2:
The patent transitions from single-point detection to multi-point simultaneous detection by introducing multiple light transmitters spaced at different positions. This dimensional expansion in the detection space allows the system to capture object edges more reliably and distinguish them from surface features, improving detection reliability without mechanical complexity
2Measurement precision
If camera-based sensors with image analysis are used, then edge detection capability is improved, but the cost and resistance to stray light deteriorate
Solution Approach 1:
The patent employs pulsed light transmission where light transmitters emit light in periodic pulses rather than continuously. This periodic action creates time-gated detection windows that reject continuous stray light background, allowing precise edge detection comparable to camera systems while maintaining immunity to stray light interference
Solution Approach 2:
The patent replaces complex camera-based image analysis systems with a simpler array of light transmitters and photodetectors. By substituting the mechanical/optical complexity of cameras with a more straightforward light emission and detection array, the system achieves comparable edge detection precision while naturally resisting stray light through the pulsed operation mode
3Reliability
If multiple light transmitters are used to scan multiple points, then edge detection robustness is improved, but the device complexity increases
Solution Approach 1:
The patent segments the detection function across multiple light transmitters, where each transmitter independently scans a specific point on the object. The evaluation unit then combines these segmented detection results through logical operations to achieve robust edge detection. This segmentation approach improves reliability without requiring a single complex transmitter
Solution Approach 2:
The patent merges the detection signals from multiple light transmitters in the evaluation unit through logical combination. By merging the simple detection results from multiple transmitters using logical OR operations, the system achieves enhanced detection robustness while keeping each individual transmitter simple and the overall device complexity manageable
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 closely spaced object edges with reduced switching errors, improved robustness against extraneous light, and eliminates the need for complex teach-in processes, enhancing detection performance in high-speed conveyor applications.
Implementation Method 1
two light transmitters (12a, b) with collimated transmission beams (16a, b)
Implementation Method 2
The object distance can then be determined by means of triangulation from the center of gravity of the received light on the receiver unit
Data Source
Figure 1~2
Figure 3a~4
Figure 5a~6c
AI summary
The sensor (10) has a spatially resolved-light receiver (26) receiving a light spot (20a) generated on transmitted light beams (16a, 16b) on objects (18). An evaluating unit (30) outputs an object detection signal during the detection of edge from receiver intensity of the light spot and/or from a determined distance with a triangulation of a position of another light spot (20b) to the receiver. The evaluating unit evaluates difference of the receiver intensity determined from the former light spot and/or distance determined from the former light spot and recognizes the edge. An independent claim is also included for a method for detecting objects moved relative to a sensor in a surveillance region based on object edges.