Optoelectronic Safety Barrier Using Camera-Image Comparison
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Solution Overview
Problem
Conventional optoelectronic safety barriers with reflecting mirrors are cumbersome, sensitive to alignment, prone to blind spots, and costly, requiring wiring for both columns and being vulnerable to tampering.
Innovation Solution
An optoelectronic safety barrier with cameras on one active column and patterns on a passive column, where cameras capture images of the patterns and compare them to a reference image to detect intrusions, reducing the need for wiring and simplifying alignment, while being less sensitive to vibrations and tampering.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Device complexity
If reflecting mirrors are used on both columns to create a passive column, then wiring complexity is reduced, but alignment precision and setup complexity increase dramatically
Solution Approach 1:
The patent removes the mirrors from the passive column entirely, extracting the problematic alignment requirement. Instead of using mirrors to reflect light back, the system uses direct optical paths from LEDs on the active column to photodiodes on the passive column, eliminating the need for precise mirror alignment while maintaining the wireless passive column architecture.
Solution Approach 2:
The patent inverts the traditional approach by placing LEDs and photodiodes on the same side (active column) rather than opposite columns. This inversion allows the passive column to remain simple and wire-free without requiring mirrors, as the active column contains all the active optical components needed to create and detect the optical beam.
2Use of energy by moving object
If mirrors are used to create a passive column, then power supply to both columns is avoided, but the system becomes more sensitive to vibration
Solution Approach 1:
The patent removes mirrors from the system entirely, extracting the vibration sensitivity problem associated with mirror alignment. By using direct optical paths between LEDs and photodiodes on the active column, the system maintains the energy-efficient passive column design while eliminating vibration-induced alignment errors.
3Ease of operation
If cameras are positioned close to the passage for gate protection, then replacement of conventional barriers is achieved, but blind spots are created in surveillance
Solution Approach 1:
The patent uses multiple cameras positioned at different locations on the active column, each viewing a specific portion of the passive column. This segmentation of the visual field allows comprehensive coverage of the passage area, eliminating blind spots while maintaining the compact gate protection configuration.
Solution Approach 2:
The patent transitions from a single-camera system to a multi-camera array, adding spatial dimensionality to the surveillance coverage. By distributing cameras across multiple positions on the active column, the system achieves three-dimensional coverage of the passage, eliminating blind spots that would exist in a single-plane configuration.
4Reliability
If multiple LED-photodiode pairs are placed on the same column, then detection capability is improved, but setup complexity and alignment difficulty increase dramatically
Solution Approach 1:
The patent merges multiple LED-photodiode pairs onto a single active column, combining their detection capabilities while using a shared power supply and control system. This consolidation maintains enhanced detection capability through multiple optical paths while reducing overall system complexity compared to distributing pairs across multiple columns.
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
The solution provides a cost-effective, easy-to-set-up, and reliable surveillance system with reduced blind spots, capable of detecting intrusions and tampering attempts, and operates with power supply only to the active column.
Implementation Method 1
both the LEDs and the photodiodes are located on one column only, while the opposite column is passive, and only has mirrors reflecting the rays emitted from the LEDs back to the photodiodes
Data Source
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AI summary
An optoelectronic safety barrier wherein two columns define entry to a danger zone, an active one (10) bearing two cameras and a passive one (12) bearing two identical geometrical patterns (18, 20) aligned on the same optical axes. A control system (22) cyclically receives and processes respective images from the cameras, flips one of the images about a line orthogonal to the active column (10), compares each of the resulting images with a stored reference image (E), and issues an alarm signal whenever a difference is found between the reference image (E) and either one of said resulting images. The geometrical configuration of patterns and cameras allows for comparison with the reference image of the image from the first camera as it is, and the image of the second camera after overturn and alignment. Correct setup and alignment can also be verified by the same image comparison.