Surface Shape Measurement with Rotary Optical Sectioning
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Solution Overview
Problem
Conventional surface shape measuring devices for rotating bodies, such as cylinders and doughnuts, are time-consuming due to the use of point lasers requiring repeated main-scanning and sub-scanning.
Innovation Solution
A surface shape measuring device utilizing an optical sectioning method with a rotary table, encoder, and optical sectioning sensor to quickly and accurately measure the surface shape by scanning with band-shaped or line-shaped light, generating three-dimensional images of the measurement surface.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If a point laser is used for surface shape measurement, then measurement precision can be maintained, but measurement time increases due to repeated main-scanning and sub-scanning
Solution Approach 1:
The patent transitions from point-by-point measurement (0D/1D scanning) to line-shaped light illumination that captures optical section lines across the entire measurement surface simultaneously (2D/3D imaging). This dimensional change allows the entire cross-section of the rotating body to be measured in one rotation cycle rather than requiring multiple scanning passes, thereby reducing measurement time while maintaining precision through the optical sectioning method
Solution Approach 2:
The patent replaces the mechanical scanning system (point laser with moving stages for main-scan and sub-scan) with an optical sectioning system using line-shaped light and image sensors. This substitution eliminates the need for complex mechanical scanning movements, allowing simultaneous capture of multiple measurement points along the illumination line, thus dramatically reducing measurement time while preserving measurement accuracy
2Productivity
If band-shaped or line-shaped light is used for optical sectioning, then measurement speed increases, but device complexity increases
Solution Approach 1:
The patent employs a rotary table that serves multiple functions: it rotates the measurement object, provides precise angular positioning through the encoder, and enables single-pass measurement of the entire circumference. This multi-functional component reduces the need for separate scanning mechanisms, thereby increasing measurement speed without proportionally increasing overall device complexity
Solution Approach 2:
The encoder acts as an intermediary between the rotary table's mechanical rotation and the measurement system's data acquisition. It provides precise angular position information that triggers image capture at specific rotation angles, enabling synchronized measurement without requiring complex real-time coordination between the light source, sensor, and rotary motion, thus simplifying the control system while maintaining high measurement speed
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
Enables rapid and precise measurement of rotating body surfaces, allowing for efficient dimensional confirmation and inspection, and the creation of three-dimensional models for easy viewing and dimension specification.
Implementation Method 1
an optical sectioning sensor that irradiates a band-shaped light or a line-shaped light onto the measurement surface and acquires optical section line image data for each rotation angle by sequentially capturing optical section lines generated by the band-shaped light or the line-shaped light
Data Source
AI summary
A surface shape measuring device measures the three-dimensional shape of a measurement surface in an object to be measured shaped as a rotating body or an approximate rotating body. The surface shape measuring device includes: a rotary table that rotates the object to be measured; an encoder that sequentially outputs signals according to the rotation angle of the rotary table; an optical sectioning sensor that irradiates light onto the measurement surface and acquires a plurality of optical section line image data by sequentially capturing optical section lines generated by the irradiated light, which move across the measurement surface as the rotary table rotates, triggered by a signal output from the encoder; and an image processing unit that generates an image showing the surface shape of the measurement surface by sequentially arranging the respective optical section line image data according to the corresponding rotation angle.