Virtual Calibration Plate for PIV Measurement Arrangement

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Solution Overview

Problem

The existing methods for calibrating Particle Image Velocimetry (PIV) measuring arrangements require a calibration plate, which increases the setup costs and complexity, and there is a need for a more efficient method that eliminates the need for a physical calibration plate.

Innovation Solution

A method that uses a computer system to create a three-dimensional computer model of the PIV measurement arrangement with a virtual calibration plate, generating artificial images using ray tracing to simulate the calibration process, thereby eliminating the need for a physical calibration plate and reducing the overall effort.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Measurement precision

If a calibration plate is used for calibrating the PIV measuring arrangement, then the calibration accuracy is ensured, but the setup costs and complexity increase

Engineering Contradiction:
Improvecalibration accuracyVSAvoidsetup complexity
Core Design Contradiction:
Measurement precisionVSDevice complexity

Solution Approach 1:

The patent creates a virtual copy of the calibration plate within a three-dimensional computer model of the measurement arrangement. This virtual calibration plate serves the same calibration function as a physical plate but eliminates the need for manufacturing, positioning, and handling actual hardware, thereby reducing setup complexity while maintaining calibration accuracy through precise digital modeling and ray-tracing-based image generation.

Inventive Principle:
Principle #26Copying

2Measurement precision

If a calibration plate is used for calibrating the PIV measuring arrangement, then the calibration process can be performed, but the effort and time required increase

Engineering Contradiction:
Improvecalibration capabilityVSAvoidcalibration time
Core Design Contradiction:
Measurement precisionVSLoss of time

Solution Approach 1:

The patent performs preliminary calibration by generating artificial calibration images from a three-dimensional computer model before actual measurements begin. The virtual calibration plate and its images are pre-computed using ray-tracing methods, allowing the calibration data to be ready in advance. This eliminates the time-consuming steps of physically setting up and adjusting a real calibration plate during the measurement process.

Inventive Principle:
Principle #10Preliminary action

Solution Approach 2:

The patent replaces the mechanical calibration process involving physical plates, cameras, and manual adjustments with a computational approach. Three-dimensional computer modeling and ray-tracing algorithms generate calibration images digitally, substituting mechanical operations with automated computer-based calculations that are faster and more consistent.

Inventive Principle:
Principle #28Mechanics substitution (Replace mechanical system)

3Measurement precision

If a physical calibration plate is used, then calibration images can be captured, but additional hardware and setup requirements are introduced

Engineering Contradiction:
Improvecalibration image qualityVSAvoidsetup requirements
Core Design Contradiction:
Measurement precisionVSEase of manufacture

Solution Approach 1:

The patent creates a virtual representation of the calibration plate within a three-dimensional computer model, eliminating the need to manufacture and physically handle a real calibration plate. The virtual plate is positioned and oriented digitally within the simulated measurement scene, and calibration images are generated through ray-tracing calculations that simulate camera captures, providing all necessary calibration data without physical hardware.

Inventive Principle:
Principle #26Copying

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 allows for a low-cost and efficient calibration process with minimal error, using the artificially generated images for rough and further calibration steps, while maintaining the accuracy of the conventional calibration method.

Implementation Method 1

the images from the cameras are artificially generated on the basis of the computer model, in particular using a ray tracing method

Methodology Applied
Scientific EffectRay tracing:

Data Source

PatentEP3924741B1Method for calibrating a piv measurement arrangement
Publication Date: 2023.08.23 VOITH PATENT GMBH
  • EP3924741B1 patent drawingFigure 1
  • EP3924741B1 patent drawingFigure 2
  • EP3924741B1 patent drawingFigure 3

AI summary

The invention relates to a method for calibrating a PIV measurement arrangement, the measurement arrangement comprising at least two cameras (1), and the method comprising three steps (V1, V2, V3), wherein: in the first step (V1), the measurement arrangement is provided; in the second step (V2), a computer system (4) is provided and the computer system (4) is used to create a three-dimensional computer model (5) of the measurement arrangement, the computer model (5) comprising a virtual calibration board (6) which is arranged inside the computer model (5) such that it is situated within the field of view of the cameras (1); and in the third step (V3), the images (3) of the cameras (1) are generated artificially on the basis of the computer model (5) with the application of a ray-tracing method.