Non-contact Vibration Analysis via Pattern Cross-correlation

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Solution Overview

Problem

Current vibration analysis methods for rotating machines are complex, expensive, and not suitable for continuous monitoring due to the need for sensitive measurement techniques, especially in environments where direct measurement is challenging, such as aggressive gases or radioactive environments.

Innovation Solution

A device and method for vibration analysis using a detection device to capture images of a pattern on a surface, with an evaluation device comparing these images to a reference image to determine vibrations, employing cross-correlation and image sensors to provide robust and quick evaluation results with minimal computing power.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Measurement precision

If conventional optical vibration analysis methods are used, then vibration measurement capability is achieved, but device complexity and cost increase significantly

Engineering Contradiction:
Improvevibration measurement capabilityVSAvoidoptical system complexity
Core Design Contradiction:
Measurement precisionVSDevice complexity

Solution Approach 1:

The patent uses a camera to capture images of a pattern projected onto the workpiece surface, creating a visual copy of the surface geometry. This optical copy is then processed through image correlation algorithms to extract vibration information, replacing complex direct measurement optics with standard imaging equipment and computational methods.

Inventive Principle:
Principle #26Copying

Solution Approach 2:

The patent replaces complex mechanical/optical measurement systems with an image-based system. Instead of using sophisticated interferometric or Doppler-based optical devices, the invention uses a camera to capture pattern images and employs digital image processing (cross-correlation algorithms) to determine surface displacement and vibration, substituting mechanical/optical complexity with computational simplicity.

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

2Measurement precision

If sensitive measurement techniques are used for continuous monitoring, then vibration detection accuracy is improved, but system cost and complexity increase

Engineering Contradiction:
Improvevibration detection accuracyVSAvoidsystem complexity
Core Design Contradiction:
Measurement precisionVSDevice complexity

Solution Approach 1:

The system creates multiple image copies of the pattern at different time instances and uses cross-correlation to compare these copies, extracting displacement information. This approach allows continuous monitoring using standard cameras rather than requiring sophisticated continuous measurement instruments.

Inventive Principle:
Principle #26Copying

Solution Approach 2:

The patent projects a known pattern onto the workpiece surface before measurement begins. This pre-established reference pattern serves as a baseline for subsequent image comparisons, enabling the system to detect vibrations by measuring deviations from this predetermined pattern configuration.

Inventive Principle:
Principle #10Preliminary action

3Measurement precision

If complex optical devices are used, then measurement capability is achieved, but ease of operation and deployment deteriorates

Engineering Contradiction:
Improvevibration analysis capabilityVSAvoiddeployment simplicity
Core Design Contradiction:
Measurement precisionVSEase of operation

Solution Approach 1:

The system uses a camera to capture images of a projected pattern, creating visual representations of the workpiece surface. These image copies can be stored, transferred, and analyzed without requiring the original measurement setup, greatly simplifying operation and enabling remote analysis.

Inventive Principle:
Principle #26Copying

Solution Approach 2:

The patent introduces a projected pattern as an intermediary between the camera and the workpiece surface. This pattern acts as a mediator that converts surface geometry and vibration into visible image variations that can be captured by standard cameras and processed through image correlation, eliminating the need for complex direct measurement optics.

Inventive Principle:
Principle #24Intermediary (Mediator)

4Measurement precision

If high computing power is used for image evaluation, then vibration analysis accuracy is improved, but energy consumption and system cost increase

Engineering Contradiction:
Improvevibration analysis accuracyVSAvoidcomputing energy consumption
Core Design Contradiction:
Measurement precisionVSUse of energy by moving object

Solution Approach 1:

The patent extracts only the essential vibration information from the captured images by using cross-correlation to determine pattern displacement. Instead of performing comprehensive image analysis, the system extracts specifically the positional shift of the projected pattern, which contains the vibration information, thereby reducing computational requirements while maintaining measurement accuracy.

Inventive Principle:
Principle #2Taking out (Extraction)

Solution Approach 2:

The system uses cross-correlation to compare image copies and extract displacement information. This mathematical operation efficiently identifies the shift between patterns without requiring full image processing, providing an computationally efficient method for vibration analysis that maintains high accuracy.

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

Enables simple, robust, and cost-effective non-contact vibration analysis of rotating components, capable of detecting high-frequency vibrations with low-power computing, suitable for continuous monitoring without the need for complex optics or high-tech sensors.

Implementation Method 1

a detection device (12) which is designed to detect a pattern (14) from a surface (16) to be measured in order to provide a detected image (18) of the pattern (14)

Methodology Applied
Scientific EffectReflection: Reflection

Implementation Method 2

The evaluation device is designed to carry out the comparison based on a cross-correlation between the captured image and the reference image

Methodology Applied
Scientific EffectCross-correlation:

Data Source

PatentEP3755978B1Devices and method for vibration analysis
Publication Date: 2022.03.16 FRAUNHOFER GESELLSCHAFT ZUR FORDERUNG DER ANGEWANDTEN FORSCHUNG EV
  • EP3755978B1 patent drawingFigure 1
  • EP3755978B1 patent drawingFigure 2a~2c
  • EP3755978B1 patent drawingFigure 3

AI summary

The invention relates to a device for vibration analysis comprising a capture unit and an evaluation unit. The capture unit is designed to capture a pattern from a surface to be measured in order to provide a captured image of the pattern. The evaluation unit is designed to evaluate the capture image in order to obtain an evaluation result by comparing the captured image with a reference image, which evaluation result includes information relating to a vibration of the surface to be measured.