Optical Code Reader Dynamic Conversion for Varying Light
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Solution Overview
Problem
Optical information reading devices face challenges in maintaining reading accuracy due to varying light conditions and low contrast codes, particularly when the distance between the code and camera changes, leading to issues like blur, noise, and reduced decoding accuracy.
Innovation Solution
An optical information reading device that includes an imaging part, a conversion part, and a decoding part, with a storage for different conversion characteristics, allowing for the selection of an optimal conversion characteristic based on analysis of decoded images to enhance reading accuracy under varying light conditions and low contrast scenarios.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Length of stationary object
If the diaphragm of the lens is reduced to increase reading depth, then the reading depth is improved, but the light amount received by the imaging element becomes insufficient
Solution Approach 1:
The patent applies parameter changes by adjusting the diaphragm opening degree as a controllable parameter. Instead of fixing the diaphragm to a small opening for deep reading depth, the system dynamically changes the diaphragm opening degree based on actual reading conditions, allowing optimization of both reading depth and light amount for different scenarios
2Illumination intensity
If the exposure time is increased to compensate for light amount deficiency, then the light amount is improved, but motion blur occurs on moving workpieces
Solution Approach 1:
The patent applies dynamics by making the exposure time a dynamic parameter that adjusts according to the movement state of workpieces and lighting conditions. The system automatically selects appropriate exposure time values from multiple preset options based on real-time conditions, enabling the balance between light amount and image clarity to change adaptively rather than remaining fixed
3Illumination intensity
If the gain is increased to compensate for light amount deficiency, then the light amount is improved, but noise increases and reading accuracy deteriorates
Solution Approach 1:
The patent applies parameter changes by adjusting the gain as a controllable parameter with multiple preset values. The system automatically selects appropriate gain levels based on actual lighting conditions and code contrast, preventing excessive noise amplification while ensuring sufficient signal strength for accurate reading
4Measurement precision
If multiple conversion characteristics are stored and selected based on analysis, then the reading accuracy is improved, but the device complexity increases
Solution Approach 1:
The patent applies preliminary action by pre-calculating and storing multiple conversion characteristics (lookup tables) during system initialization or setup. These pre-prepared conversion characteristics are then simply selected based on analyzed image conditions, avoiding the need for complex real-time calculations and reducing processing complexity during actual operation
Data Source
AI summary
[Object] To enhance a reading accuracy of a code even when a light amount, which can be received by an imaging element, varies greatly. [Means to solve the problems] A plurality of second images in response to a plurality of different conversion characteristics is generated by using the first image obtained at the time of setting of an optical information reading device. The results, in which codes included in the generated second images are respectively decoded by a decoding part, are analyzed, and one of the conversion characteristics is selected. The second image in response to the selected conversion characteristic is generated by using the first image at the time of operation of the optical information reading device.