Volume Imaging Equation Correction for 3D Particle Velocity
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Existing methods for determining a three-dimensional velocity field in a volume, such as Particle Image Velocimetry and tomographic PIV, face challenges with particle density and calibration accuracy, leading to errors from overlapping particles and optical distortions.
Innovation Solution
A method that involves capturing a volume from multiple directions using at least two cameras, performing a coarse calibration to determine an initial imaging equation, and then calculating correction factors based on the differences between calculated and actual camera coordinates to ensure accurate particle association and minimize errors, allowing for precise triangulation and correction of imaging equations.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If particle density is increased to improve measurement signal, then velocity field determination becomes more robust, but particle overlapping increases leading to measurement errors
Solution Approach 1:
The patent divides the volume into multiple interrogation volumes and further segments particles into individual detectable entities within each volume. By processing particles in segmented spatial regions and using multi-camera triangulation to uniquely identify individual particles, the system can handle higher particle densities without overlapping errors affecting the entire measurement field.
Solution Approach 2:
The patent introduces an intermediary calibration and correction process that uses a calibration plate with known particle positions to establish accurate imaging equations. This intermediary step creates a reference framework that enables precise particle position determination even in high-density environments, mediating between the increased particle density and the need for measurement precision.
2Measurement precision
If calibration accuracy is improved to reduce optical distortion errors, then velocity field determination becomes more precise, but calibration complexity and time increase
Solution Approach 1:
The patent performs calibration as a preliminary action before actual velocity measurements. By establishing accurate imaging equations and correction factors in advance using a calibration plate, the system prepares the measurement framework beforehand, enabling precise velocity field determination without adding complexity to the ongoing measurement process.
Solution Approach 2:
The patent uses a calibration plate that creates a known copy or reference pattern of particle positions. This reference copy with precisely known coordinates serves as a template for determining accurate imaging equations, simplifying the calibration process by providing a standardized reference object rather than requiring complex iterative adjustments.
3Adaptability or versatility
If triangulation method is used to determine particle positions, then three-dimensional velocity field can be obtained, but erroneous particle associations occur leading to measurement errors
Solution Approach 1:
The patent implements feedback through the calibration process where known particle positions from the calibration plate are used to verify and correct the triangulation results. The imaging equations are refined based on feedback from the calibration data, ensuring that subsequent particle associations in the actual measurement are accurate and reducing erroneous associations.
Solution Approach 2:
The patent replaces direct mechanical/optical triangulation with a computational approach using pre-determined imaging equations. Instead of relying solely on geometric triangulation which can produce ambiguous results, the system substitutes a mathematical model based on calibration data that more reliably associates particles across multiple cameras, reducing erroneous associations.
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 enhances the accuracy of velocity field determination by correcting imaging equations and reducing errors, enabling more precise calibration and minimizing erroneous particle associations, even in high-density particle environments.
Implementation Method 1
the particles located in the volume radiating by illuminating the volume
Implementation Method 2
the (X, Y, Z) position of the particles is determined by triangulation
Data Source
AI summary
The subject matter of the invention is a method of correcting a volume imaging equation for more accurate determination of a velocity field of particles in a volume, said volume being captured from different directions by at least two cameras, a coarse calibration of the position of the cameras relative to each other and relative to the volume of concern being carried out first by determining an imaging equation that associates with the coordinates (X, Y, Z) of a point in the volume the corresponding camera picture coordinates xi, yi of each camera i, all the cameras then capturing simultaneously in the same unchanged position particles in a volume, the position (X, Y, Z) of a particle in the volume being approximated by means of a known triangulation method using the calculated position xi, yi of a particle in the camera pictures, this position (X, Y, Z) being imaged through the original imaging equation onto a position xi′, yi′ in the camera images of the at least two cameras, a correction factor for the imaging equation being calculated from the difference (dxi, dyi) between the coordinates (xi, yi) and (xi′, yi′) so that, thanks to the amended imaging equation, the point (xi, yi) becomes identical with the point (xi′, yi′) for all the cameras i, this correction occurring for many particles in the volume.