Optical Encoder Position Detection Using Virtual Image Shifting
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Solution Overview
Problem
Optical encoders face challenges in achieving high accuracy without increasing the size of the disc or the resolution of patterns, which would hinder miniaturization and increase costs, leading to reduced competitiveness.
Innovation Solution
An optical encoder system that includes a disc with a pattern, a sensor to capture images of the pattern, and a processor that shifts reference images to compare with the captured image, allowing for increased resolution without enlarging the disc or increasing pattern resolution by determining the position based on similarity and calibration phases.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If the size of the code plate is increased to improve measurement precision, then the accuracy of the detected position is improved, but the miniaturization of the encoder is hindered
Solution Approach 1:
The patent creates multiple virtual copies of the code pattern through software processing. The single physical code plate is captured by the sensor, and then multiple virtual code plates are generated by shifting and comparing the captured image data. This allows the system to achieve high measurement precision without requiring a physically larger code plate, effectively resolving the contradiction between measurement precision and device size.
2Measurement precision
If the resolution of the patterns on the code plate is increased to improve measurement precision, then the accuracy of the detected position is improved, but the cost increases which reduces market competitiveness
Solution Approach 1:
Instead of manufacturing code plates with higher physical resolution, the patent captures the existing code plate image and creates multiple high-resolution virtual copies through software processing. The captured image is shifted in multiple directions and compared to generate virtual code plates with effectively higher resolution, eliminating the need for expensive high-resolution manufacturing while achieving improved measurement precision.
Solution Approach 2:
The patent changes the parameter of resolution from a physical manufacturing parameter to a software processing parameter. By capturing the code plate image and processing it through shifting and comparison operations, the system achieves effective high resolution without the cost penalties of manufacturing high-resolution physical patterns. This transforms resolution from a costly hardware parameter to a computationally achieved parameter.
3Measurement precision
If multiple code plates are used to improve measurement precision through comparison, then the accuracy is improved, but the device complexity increases
Solution Approach 1:
The patent eliminates the need for multiple physical code plates by creating multiple virtual code plates from a single captured image. The processor generates multiple virtual copies by shifting the captured image data in different directions and comparing them, achieving the benefits of multiple code plate comparison while using only one physical code plate, thus reducing device complexity while maintaining improved measurement precision.
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 enhances accuracy by effectively determining the position of a rotatable mechanism with increased resolution without the need for larger discs or higher resolution patterns, thus maintaining miniaturization and reducing costs.
Implementation Method 1
The sensor is configured to obtain an image of a portion of the pattern
Implementation Method 2
The sensor is configured to obtain an image of a portion of the pattern
Data Source
AI summary
An encoder connected to an object is provided. The encoder includes a plate, a sensor, a memory and a processor. The plate has a pattern thereon. The sensor is configured to obtain an image of a portion of the pattern. The memory is configured to store a first set of reference images corresponding to a portion of the pattern and angle and/or position information corresponding to the first set of images. The processor is configured to shift the first set of reference images to obtain a second set of reference images and to compare the obtained image with the first set of reference images and/or the second set of reference images.