Multi-Camera Symbol Reader for Wide Distance Coverage
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Solution Overview
Problem
Existing optical information reading devices face challenges in rapid symbol reading due to sequential processing times and limited readable distance ranges, especially when dealing with symbols at varying distances and sizes.
Innovation Solution
An optical information reading device equipped with a first and second fixed-focus camera and a variable-focus camera, allowing simultaneous image capture across a wide range of distances by controlling the focal length of the variable-focus camera to fill gaps in readable areas.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Duration of action of stationary object
If a sequential operation of activating fixed focus camera after autofocus camera is used, then the frequency of using autofocus camera is reduced and mechanical lifespan is extended, but processing time increases when fixed focus camera imaging is deemed unsuitable
Solution Approach 1:
The imaging system is segmented into multiple fixed focus cameras with different focal lengths (first fixed focus camera for short distances, second fixed focus camera for long distances) and a variable focus camera, allowing parallel processing without sequential activation, thus reducing processing time while extending mechanical lifespan
Solution Approach 2:
The variable focus camera provides dynamic focus adjustment capability to fill gaps in readable distance ranges, enabling the system to adapt to symbols at varying distances simultaneously with fixed focus cameras, eliminating the need for sequential operation
2Area of stationary object
If fixed focus camera with four eyes is used to reduce discrepancy in reading area, then reading area coverage is improved, but for smaller code sizes the readable distance range becomes narrower creating gaps
Solution Approach 1:
The reading system is divided into multiple distance segments, with each fixed focus camera handling specific distance ranges (first for short distances, second for long distances), and the variable focus camera filling intermediate gaps, ensuring continuous coverage from close to far distances
Solution Approach 2:
The focal length parameter is varied across different cameras (first focal length for short distance, second focal length for long distance, and variable focal length for intermediate ranges), allowing the system to adapt to different code sizes and distances without creating gaps in readable areas
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
Enables rapid and reliable reading of symbols over a wide distance range without the need for sequential processing, improving operability and controllability while expanding the overall readable area.
Implementation Method 1
an imaging element that converts the light received by the optical system into an electrical signal to generate an image
Data Source
AI summary
The imaging device comprises a first fixed-focus camera, a second fixed-focus camera, and a variable focus camera. The control device reads information of the symbol based on the first image from the first fixed-focus camera, the second image from the second fixed-focus camera, and the third image from the variable focus camera. The control device controls the focal length changing device of the variable focus camera such that the focal length of the variable focus camera is longer than the first focal length of the first fixed-focus camera and shorter than the second focal length of the second fixed-focus camera. The control device reads the information of the symbol based on the third image, which is focused at a distance farther than the first image and closer than the second image, generated by the variable focus camera under the controlled focal length.