Dual Imaging Measuring Device for Surface Shape and Roughness
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Solution Overview
Problem
White light interferometers face noise issues near the surface of workpieces, leading to instability and false detection during shape and roughness measurements, which affects the accuracy of surface analysis.
Innovation Solution
A measuring device with a dual imaging system, where the first imaging unit captures a wider field and detects surface position and edges, while the second imaging unit uses white light interferometry for precise shape and roughness measurement, integrating data to enhance accuracy and reduce noise.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If white light interferometry is used for non-contact measurement of surface shape and roughness, then measurement capability is achieved, but noise is generated near the surface causing instability and false detection
Solution Approach 1:
The measurement system is divided into two independent imaging units: a first imaging unit for capturing wide-field images and a second imaging unit for high-precision interferometric measurements. By segmenting the measurement function, the patent allows each unit to specialize in specific tasks, with the first unit providing contextual information and the second unit providing precise measurements, thereby reducing noise interference in the final measurement results.
Solution Approach 2:
The patent merges the output of two different imaging units into a unified measurement system. The image processing unit combines data from both the first imaging unit (wide-field images) and the second imaging unit (interferometric images) to produce final measurement results. This merging allows the system to leverage the strengths of both approaches while mitigating their individual weaknesses, particularly the noise issues in white light interferometry.
2Measurement precision
If a single imaging unit is used for measurement, then device complexity is reduced, but measurement accuracy is compromised due to noise
Solution Approach 1:
The measurement function is segmented into two specialized imaging units, each performing a specific role: the first imaging unit captures wide-field images for contextual information and position detection, while the second imaging unit performs high-precision interferometric measurements. This segmentation allows each unit to be optimized for its specific function, improving overall measurement accuracy despite the increased device complexity.
Solution Approach 2:
The patent creates a multi-functional measurement system where the first imaging unit serves multiple purposes: capturing wide-field images, detecting surface position, and providing contextual information for the second imaging unit. The second imaging unit primarily performs high-precision interferometric measurements. This multi-functionality justifies the added complexity by maximizing the utility of each imaging unit.
3Measurement precision
If white light interferometry scans the surface in Z-axis direction, then shape and roughness can be measured, but noise is generated in the vicinity of the surface
Solution Approach 1:
The first imaging unit acts as an intermediary that captures wide-field images and provides contextual information about the surface position and geometry. This intermediary data is then used to guide and interpret the measurements from the second imaging unit, effectively filtering out noise by providing a reference framework that distinguishes true surface features from noise artifacts.
Solution Approach 2:
The system creates a complementary measurement approach by using the first imaging unit to capture the overall surface context and the second imaging unit to capture detailed interferometric data. The image processing unit then synthesizes these two different types of data, using the first unit's data as a reference copy to validate and interpret the second unit's measurements, thereby reducing noise interference.
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 device achieves accurate measurement of surface shape and roughness by combining data from both imaging units, effectively mitigating noise and improving detection precision.
Implementation Method 1
a second imaging unit configured to image the surface of the workpiece on the table, the second imaging unit allowing measurement of a shape and/or roughness of the surface of the workpiece according to a plurality of images taken by scanning the surface of the workpiece in a Z-axis direction
Data Source
AI summary
A measuring device includes a table on which a workpiece is to be mounted, a first imaging unit configured to image the surface of the workpiece on the table, a second imaging unit configured to image the surface of the workpiece on the table, the second imaging unit allowing measurement of a shape and/or roughness of the surface of the workpiece according to a plurality of images taken by scanning the surface of the workpiece in a Z-axis direction, and an image processing unit configured to process the image of the surface of the workpiece taken by the first imaging unit and the plurality of images taken by scanning the surface of the workpiece in the Z-axis direction by the second imaging unit, so as to measure the shape and/or the roughness of the surface of the workpiece.