Segmented Linear Sensor Array for Distance-Aware Symbol Decoding
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Solution Overview
Problem
Existing machine-readable symbol readers face challenges in accurately decoding symbols at varying distances due to limitations in distance measurement and focusing, which affects the quality of image capture and decoding efficiency.
Innovation Solution
A miniaturized imaging system with a linear image sensor and a range finder, utilizing a portion of the sensor array for imaging symbols and another portion for estimating the reading distance, allowing for extended depth of field and precise distance measurement, enabling effective decoding of symbols across different scanning distances.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Device complexity
If a conventional imaging system uses a single sensor array for both imaging and distance measurement, then the device complexity is reduced, but the measurement precision and imaging quality deteriorate due to competing requirements for sensor allocation
Solution Approach 1:
The sensor array is segmented into two distinct functional regions: a first portion dedicated to imaging machine-readable symbols and a second portion dedicated to range finding. This segmentation allows each portion to be optimized for its specific function, with the imaging portion capturing symbol information and the range finding portion measuring distance by detecting the periphery of the projected light pattern, thereby resolving the conflict between system simplicity and measurement precision
Solution Approach 2:
Different regions of the sensor array are assigned different functional qualities: the first portion has imaging quality optimized for capturing machine-readable symbols, while the second portion has range finding quality optimized for detecting light pattern periphery. This local differentiation enables each region to perform its specific function with high precision without compromising the other
2Manufacturing precision
If the imaging system focuses on a single distance plane, then the imaging quality is optimized for that specific distance, but the adaptability to decode symbols at varying distances deteriorates
Solution Approach 1:
The range finder provides real-time feedback about the distance to the target object by measuring the periphery of the projected light pattern. This distance information is fed back to the processor, which then adjusts the focusing of the imaging system to match the measured distance, enabling the system to maintain optimal image capture quality across varying distances while decoding machine-readable symbols
3Manufacturing precision
If the system uses a larger sensor array to improve imaging resolution, then the imaging quality improves, but the device size and cost increase
Solution Approach 1:
The sensor array is segmented into two functional portions, allowing the total array size to be smaller than what would be required if the entire array were dedicated to imaging. The first portion handles imaging while the second portion handles range finding, enabling the system to achieve adequate imaging resolution for symbol decoding without requiring a large sensor array, thus reducing device size and cost
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 system enables successful decoding of machine-readable symbols at various distances by providing accurate distance information for localization and decoding processes, improving the overall efficiency and accuracy of symbol reading.
Implementation Method 1
a linear array of photosensitive elements which focuses light from a target object onto the linear array to capture an image of the target object
Implementation Method 2
an illumination subsystem which includes at least one light source that projects light onto the target object
Implementation Method 3
utilizing a portion of the sensor array for imaging symbols and another portion for estimating the reading distance
Data Source
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AI summary
Systems and methods of operation for a machine-readable symbol reader for estimating the distance of a scanned target object or item labeled with indicia, such as a machine-readable symbol. The reader may include an illumination subsystem which projects a light pattern (e.g., line) out from the reader. The reader may capture an image of the target object while the light pattern is projected thereon and analyze at least one detectable characteristic of the pattern to estimate distance of the target object relative to the reader. A one-dimensional sensor array of the reader may be exploited in part for imaging a symbol and in part for imaging detectable characteristics (e.g., edges) of the projected illumination pattern which allows for estimation of the reading distance. A central portion of the one-dimensional sensor array may be dedicated to imaging a machine-readable symbol and lateral portions may be dedicated to implementing a range finder.