Inclined Optical Path Image Correlation Displacement Sensor
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Solution Overview
Problem
Image correlation displacement sensors struggle to accurately measure displacement along a direction perpendicular to a target surface due to the limitations of speckle field imaging, which is typically aligned normal to the detector and target surface.
Innovation Solution
The implementation of an image correlation displacement sensor with a compact and economical configuration that includes inclined optical paths and a deflection element to capture speckle fields, allowing for the measurement of displacement along both parallel and perpendicular directions to the target surface using a single detector.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If speckle fields are imaged along a direction normal to the detector and target surface, then the imaging system is simple and economical, but the displacement measurement capability is limited to directions parallel to the target surface
Solution Approach 1:
The patent introduces inclined optical paths that are not normal to the target surface, adding a new dimension to the measurement capability. By using optical paths at angles (first optical path at an angle, second optical path at a different angle), the system can measure displacements in multiple directions including perpendicular to the surface, thereby resolving the contradiction between measurement versatility and optical simplicity
Solution Approach 2:
The imaging system is segmented into multiple independent optical paths (first optical path and second optical path), each capable of capturing speckle field images from different angles. This segmentation allows the system to measure different displacement components simultaneously, enhancing versatility without requiring a completely complex integrated system
2Measurement precision
If multiple optical paths are used to measure displacement in multiple directions, then measurement precision is improved, but device complexity increases
Solution Approach 1:
Each optical path is designed to serve multiple functions: capturing speckle field images for displacement measurement in specific directions. The first optical path measures displacement in one direction while the second optical path measures in another direction, allowing a single system to perform multiple measurement functions simultaneously, thereby achieving high precision without proportionally increasing complexity
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 high-accuracy measurement of positional displacement in multiple degrees of freedom, including six degrees of freedom, with a simple and cost-effective setup.
Implementation Method 1
A speckle field is produced by illuminating an optically rough surface with the coherent light source. Specifically, a target surface is illuminated with coherent light, and light scattered from the target surface is detected
Implementation Method 2
an element which deflects at least one of the first and second optical paths
Data Source
AI summary
An image correlation displacement sensor for measuring a displacement component along a direction perpendicular to a target surface, with a simple configuration. The sensor may include: an illumination portion (130′) which emits illumination light; an imaging portion including at least two optical paths (A and B′) which are used to capture multiple images of a speckle field produced by the target surface (300), one of which (A) is inclined with respect to a normal to the target surface in proximity to the target surface, and an element (110′) which deflects an at least one of the optical paths (A and B′); and a processing portion (200) which measures a displacement relative to the target surface along a direction which includes a component normal to the target surface (300) in accordance with the correlation of multiple images captured in the optical paths (A) and (B′).