Liquid Lens Code Reader Voltage Table Correction
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Solution Overview
Problem
Liquid lenses used in code reading apparatuses face a challenge in maintaining accurate and fast focusing over time due to changes in the properties of the liquids, leading to a gradual shift in the relationship between focal distance and applied voltage, which affects the ability to keep a subject in focus.
Innovation Solution
A code reading apparatus and computer program product that include a liquid lens, a focus drive section, an image pickup section, a light emitting section for laser focus adjustment, a contrast focus section for adjusting focus based on image data contrast, and a correction section to update the applied voltage table based on the distance to the subject and the voltage required for focus, ensuring continuous accuracy and speed.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a table of the initial relationship between focal distance and applied voltage is kept and used, then the device structure is simple and initial focusing is fast, but as time passes the focus accuracy deteriorates due to liquid property changes
Solution Approach 1:
The system performs self-correction by automatically detecting focus accuracy and updating the applied voltage table without external intervention. The correction section uses image data and contrast information to self-adjust the focal distance-voltage relationship, allowing the liquid lens system to maintain accuracy despite liquid property degradation over time.
Solution Approach 2:
The system implements feedback by continuously monitoring focus quality through image data analysis and using this information to correct the applied voltage table. The correction section receives feedback from the image pickup section about actual focus conditions and adjusts the voltage-focal distance mapping accordingly, creating a closed-loop control system that adapts to liquid property changes.
2Reliability
If the applied voltage table is dynamically corrected, then focus accuracy is maintained over time, but the processing time and computational load increase
Solution Approach 1:
The system performs preliminary correction by proactively updating the applied voltage table before significant focus degradation occurs. The correction section periodically or event-driven updates the voltage-focal distance relationship based on detected focus conditions, preventing accumulation of errors and maintaining accuracy without requiring constant real-time computation.
Solution Approach 2:
The system applies partial correction by updating only the necessary portions of the applied voltage table rather than completely recalculating all values. The correction section selectively adjusts voltage mappings based on actual focus deviations, reducing computational load while maintaining sufficient accuracy for the application.
3Speed
If laser focus adjustment is used, then focusing speed is fast, but the measurement precision of focal distance decreases due to bright point position detection limitations
Solution Approach 1:
The system merges two focus adjustment methods: laser focus adjustment for rapid initial focusing and contrast focus adjustment for precise focal distance measurement. The laser section provides fast feedback on whether the subject is in focus, while the contrast section refines the focal distance measurement by analyzing image contrast characteristics, combining the speed advantage of laser with the precision advantage of contrast analysis.
Solution Approach 2:
The contrast focus adjustment section acts as an intermediary that bridges the laser focus section and the final focus determination. It receives the rapid laser focus indication and uses image contrast analysis to mediate between the fast laser measurement and the required precise focal distance, translating the laser's speed advantage into accurate focus positioning.
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 enables the code reading apparatus to maintain accurate and fast focusing by dynamically correcting the applied voltage table, ensuring the liquid lens can maintain focus on a subject despite changes in liquid properties over time, thereby extending the apparatus's operational period.
Implementation Method 1
a liquid lens; a focus drive section which applies an applied voltage to the liquid lens to adjust a focal distance of the liquid lens
Implementation Method 2
a light emitting section which emits a laser light beam in the image pickup direction; a laser focus section which makes the image pickup section obtain image data of a subject in a state in which the laser light beam is emitted, and finds a distance from the liquid lens to the subject based on a position of a bright point formed by the laser light beam
Implementation Method 3
an image pickup section which obtains image data in an image pickup direction in which the liquid lens faces; a contrast focus section which makes the image pickup section obtain image data of the subject while changing the focal distance of the liquid lens within a preset change range, so as to perform contrast focus adjustment such that the subject is brought into focus based on a magnitude of contrast of the subject included in the obtained image data
Data Source
AI summary
A code reading apparatus includes: a storage section storing an applied voltage table showing a relationship between a focal distance of a liquid lens and an applied voltage to the liquid lens; a laser focus section performing laser focus adjustment; a contrast focus section performing contrast focus adjustment; and a correction section correcting a content of the applied voltage table based on a distance from the liquid lens to a subject found by the laser focus section and a corresponding applied voltage with which the subject is brought into focus by the contrast focus section.