Light Grid Passage Monitoring with Height-Based Object Evaluation
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Existing security surveillance methods using light grids for passage control lack flexibility in handling objects of varying shapes and sizes, requiring precise standardization and positioning, which increases complexity and storage requirements.
Innovation Solution
Dividing the light grid into two sub-areas for evaluation, where objects are initially 'muted' in the lower sub-area and only trigger the safety function if they interrupt the upper sub-area, using height information to determine if the object is permitted, eliminating the need for explicit shape recognition and reducing storage and evaluation efforts.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If complete contour comparison or complete line contour comparison is performed for object recognition, then measurement precision is improved, but device complexity and storage requirements increase significantly
Solution Approach 1:
The invention extracts only the essential feature (height information from uppermost/lowermost light beams) needed for object recognition, discarding unnecessary detailed contour information. This extraction approach maintains sufficient recognition accuracy while dramatically reducing evaluation complexity and storage requirements.
Solution Approach 2:
Instead of storing and comparing complete contour patterns, the invention uses simplified reference values representing only the critical height characteristics. This copying of essential features rather than full details reduces the data burden while preserving recognition capability.
2Reliability
If standardized objects with precise positioning are required for light grid muting, then reliability is improved, but adaptability to varying object shapes deteriorates
Solution Approach 1:
The invention applies different evaluation criteria to different regions of the light grid. The uppermost and lowermost light beams (critical regions) are evaluated for height information, while intermediate beams are not strictly required to match. This local differentiation maintains reliability for safety-critical measurements while providing flexibility for objects with varying intermediate characteristics.
Solution Approach 2:
The invention changes the evaluation parameter from complete contour matching to height-based evaluation using uppermost and lowermost light beams. This parameter transformation allows the system to maintain reliable safety monitoring while adapting to various object shapes, as long as the critical height parameters fall within acceptable ranges.
3Measurement precision
If a large number of light beams (e.g., 200 beams) are used in the light grid, then measurement precision is improved, but the effort for quick comparison and storage capacity increases
Solution Approach 1:
The invention extracts only the information from the uppermost and lowermost light beams that are critical for height determination, ignoring the intermediate beams for the purpose of object recognition comparison. This extraction maintains detection resolution while reducing comparison effort to evaluating only these critical beams.
Solution Approach 2:
The invention uses a partial evaluation approach, assessing only the essential uppermost and lowermost light beam positions rather than all light beams. This partial action provides sufficient measurement precision for safety monitoring while dramatically reducing the computational and storage burden compared to evaluating all 200+ beams.
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 flexibility and reliability in processing objects of different shapes, reduces storage requirements, and simplifies the monitoring process without affecting throughput speed or increasing complexity, ensuring high reliability and efficiency in passage control.
Implementation Method 1
transmitting units arranged one above the other emit light beams which are received by correspondingly arranged receiving units. The interruption of the light beams signals the passage of an object.
Data Source
Figure 1
Figure 2a~2h
Figure 3
AI summary
The method involves transporting an object on a carrier device (12) through a passage. The passage is protected by a light grid (16) with multiple light rays (22), which run above each other. The light grid is separated in a lower area (16a) and another upper area (16b). The lower area passes through the carrier device and the upper area passes through the object, where the light grid comprises an evaluation circuit. An independent claim is also included for a light grid with an evaluation unit for execution of a passage monitoring method.