Dual Light-Sheet Flow Measurement for 3D Particle Positioning
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Solution Overview
Problem
Current methods for measuring the three-dimensional velocity field of a moving fluid are either intrusive or require high computing power and have low accuracy, and there is no non-intrusive, efficient method for determining turbulence topology.
Innovation Solution
A device and method using two light sheets with different electromagnetic properties, such as wavelengths or polarizations, to measure the position of objects in a moving fluid, allowing for three-dimensional positioning through image processing that combines light intensity values from both sheets.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Object-affected harmful factors
If particle imaging velocimetry (PIV) is used to measure flow velocity, then non-intrusive measurement is achieved, but only single-plane measurement is possible resulting in uncertainty in three-dimensional velocity topology
Solution Approach 1:
The patent transitions from single-plane (2D) measurement to three-dimensional (3D) measurement by introducing a second light sheet oriented perpendicular to the first. This allows simultaneous measurement in multiple dimensions, capturing the full three-dimensional velocity topology without requiring complex defocusing procedures.
2Loss of information
If defocusing method is used for three-dimensional PIV measurement, then three-dimensional position measurement becomes possible, but image processing requires very high computing power and accuracy is reduced
Solution Approach 1:
The patent segments the measurement space into two distinct planes illuminated by two separate light sheets with different electromagnetic properties. This segmentation allows independent detection and processing of each plane's data, simplifying the overall image processing compared to attempting to extract 3D information from a single defocused image.
Solution Approach 2:
The patent changes the electromagnetic parameters (wavelength or polarization) of the two light sheets to create distinguishable signals. This parameter differentiation enables straightforward identification and processing of particles in each light sheet, avoiding the complex deconvolution required in defocusing methods.
3Loss of information
If defocusing method is used for three-dimensional PIV measurement, then depth information can be obtained, but measurement accuracy is low because it depends on edge detection in blurred images
Solution Approach 1:
Instead of extracting depth information from blurred images through complex edge detection, the patent uses two distinct light sheets with different electromagnetic properties. This allows direct measurement of position in the third dimension by detecting which light sheet illuminates the particle, providing accurate depth information without blurring artifacts.
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, non-intrusive, and accurate measurement of three-dimensional positions and velocities of objects in a moving fluid by simplifying image processing and reducing computational complexity.
Implementation Method 1
a light emission module; a first light sheet and a second light sheet, said first and second light sheets being emitted by the light emission module
Implementation Method 2
A sensor for light scattered by the object
Data Source
Figure 1~2
Figure 3a~3b
Figure 4a~4b
AI summary
Device (3) for measuring the position of an object (3.1) in a moving fluid, said device comprising: - a light-emitting module (30, 31); - a first light sheet (32) and a second light sheet (33), said first and second light sheets (32, 33) being emitted by the light-emitting module (30, 31), each light sheet extending in a sheet plane and having a variable light intensity along a direction substantially normal to the sheet plane, the sheet plane of the first light sheet (32) being substantially parallel to the sheet plane of the second light sheet (33); - A light sensor (34) diffused by the object (3.1); - A control module (35) connected to the light-emitting module (30, 31) and to the light sensor (34).