Liquid Surface Inclination Sensor Error Reduction
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Solution Overview
Problem
Liquid surface reflection type inclination sensors face errors due to unnecessary reflected light from the container ceiling and optical components, which cannot be completely eliminated by existing designs.
Innovation Solution
The sensor includes a storage section for detection images and illumination control values when the liquid surface is removed from the optical path, allowing the arithmetic section to subtract and adjust for these reflections, ensuring accurate inclination angle calculations by equalizing illumination control values and using proportional relationships to predict detection images.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Object-affected harmful factors
If the ceiling of the container is formed into an inclined surface to deflect reflected light, then unnecessary reflected light from the container ceiling is reduced, but water bubbles attach to the corner forming at the end portion of the inclined surface and create error images
Solution Approach 1:
The patent extracts and removes the harmful reflected light component by capturing an image when the liquid surface is removed from the optical path, then subtracting this extracted interference pattern from the measurement image, thereby eliminating the error source while preserving the measurement capability
Solution Approach 2:
The patent performs preliminary action by pre-capturing the interference image when the liquid surface is removed, storing it in memory, and then using this pre-acquired data to eliminate errors during actual inclination measurements, allowing real-time correction without requiring physical modifications during measurement
2Illumination intensity
If optical components are added to the optical path to control light reflection, then light control improves, but reflection occurs on the surface of optical components and creates additional unnecessary reflected light
Solution Approach 1:
The patent extracts the complete interference pattern including all reflections from optical components by capturing an image with the liquid surface removed, then subtracts this extracted pattern from measurement images, thereby eliminating errors from both container ceiling and optical component reflections simultaneously
Solution Approach 2:
The patent creates a copy of the interference pattern by capturing an image when the liquid surface is removed, storing this copy in memory, and then using this copied pattern to subtract and eliminate the interference from subsequent measurement images, avoiding the need for additional physical interference suppression components
3Measurement precision
If the liquid surface is used for reflection-based measurement, then inclination detection is achieved, but the reflectance of the liquid surface is low and most light flux is transmitted through, causing errors from images reflected by the container ceiling
Solution Approach 1:
The patent introduces an intermediary approach by using image processing and arithmetic subtraction as a mediator between the weak reflected light signal and the final measurement result, eliminating the need to increase light intensity or add complex optical components while achieving accurate inclination detection
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
This approach effectively eliminates the influence of unnecessary reflected light, reducing errors and improving the accuracy of inclination angle measurements.
Implementation Method 1
light is irradiated onto the barcode pattern 13 from the illumination section 11 and reflected by the surface of the liquid 18
Implementation Method 2
a λ/4 plate 17
Data Source
AI summary
To eliminate influences of unnecessary reflected light other than a liquid surface in a liquid surface reflection type inclination sensor. In order to attain the object described above, an inclination sensor includes a liquid that forms a liquid surface, an illumination section, a barcode pattern to be illuminated by the illumination section, an optical system that projects the barcode pattern on the liquid surface, a light receiving element that detects the barcode pattern, a storage section that stores a detection image when the liquid surface is removed from an optical path of the optical system, and an arithmetic section that calculates an inclination angle by subtracting the detection image when the liquid surface is removed from a detection image when the liquid surface is present on the optical path of the optical system.