Ultrasonic Multi-Resolution Imaging for Micro-Defect Quantification

Resolve Bottlenecks,
Find Innovative SolutionsGenerate Solutions

Solution Overview

Problem

Traditional ultrasonic testing methods struggle to simultaneously achieve high lateral resolution and detection depth for micro-defects, especially those smaller than the probe's focal column diameter, leading to reduced signal-to-noise ratio and limited detection capability, particularly in high-performance parts like 3D printed nickel-based superalloys.

Innovation Solution

A quantitative detection method using low-frequency ultrasonic multi-resolution scanning imaging, involving calibration, fast Fourier transform, band-pass filtering, and split spectrum processing to decompose signals into sub-signals with different center frequencies, enabling multi-resolution scanning images and directivity function analysis to accurately quantify defect sizes.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Measurement precision

If high-frequency ultrasonic probes are used to improve lateral resolution, then lateral resolution is improved, but detection depth is reduced and signal-to-noise ratio deteriorates

Engineering Contradiction:

Improvelateral resolutionVSAvoiddetection depth

Core Design Contradiction:

Measurement precisionVSReliability

Solution Approach 1:

The patent divides the ultrasonic signal spectrum into multiple frequency bands through spectral decomposition. By segmenting the signal processing into different frequency components, the system can analyze defects at multiple resolution levels simultaneously, achieving high lateral resolution for small defects while maintaining detection depth through lower frequency components.

Inventive Principle:

Principle #1Segmentation

Solution Approach 2:

The patent transforms the single-frequency ultrasonic detection into multi-frequency spectral analysis. By adding the frequency dimension to the traditional time-domain signal processing, the system can resolve defects of different sizes at different depth levels, effectively resolving the contradiction between lateral resolution and detection depth.

Inventive Principle:

Principle #17Another dimension (Dimensionality change)

2Measurement precision

If probe aperture is increased to improve lateral resolution, then lateral resolution is improved, but device complexity and cost increase

Engineering Contradiction:

Improvelateral resolutionVSAvoidprobe structure

Core Design Contradiction:

Measurement precisionVSDevice complexity

Solution Approach 1:

The patent changes the frequency parameter of the ultrasonic signal rather than physically modifying the probe aperture. By using spectral decomposition to create virtual high-resolution images from low-frequency signals, the system achieves improved lateral resolution without increasing probe complexity or cost.

Inventive Principle:

Principle #35Parameter changes

3Measurement precision

If focal length is reduced to improve lateral resolution, then lateral resolution is improved, but detection depth range is limited

Engineering Contradiction:

Improvelateral resolutionVSAvoiddetection depth range

Core Design Contradiction:

Measurement precisionVSLength of moving object

Solution Approach 1:

The patent segments the detection process into multiple frequency bands, each providing different resolution characteristics. Low-frequency components provide deep penetration while high-frequency components provide fine resolution, allowing the system to maintain both wide detection depth range and high lateral resolution simultaneously through multi-resolution image fusion.

Inventive Principle:

Principle #1Segmentation

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

The method enhances signal-to-noise ratio, detection depth, and lateral resolution, allowing accurate quantification of micro-defects down to hundreds of microns, overcoming limitations of high-frequency focusing probes and phased array ultrasonic imaging.

Implementation Method 1

collecting ultrasonic A-type echo signals

Methodology Applied

Scientific EffectUltrasonic reflection: Reflection

Implementation Method 2

low-frequency ultrasonic probe

Methodology Applied

Scientific EffectUltrasonic: Ultrasound

Implementation Method 3

Performing fast Fourier transform on the acquired echo signals x(t) to obtain an amplitude spectrum A(f) thereof

Methodology Applied

Scientific EffectFast Fourier transform:

Implementation Method 4

Performing band-pass filtering with the center frequency fi on the signals x(t) using split spectrum processing to decompose the signals x(t) into N sub-signals yi(t) with different center frequencies fi

Methodology Applied

Scientific EffectBand-pass filtering: Filter (electronic)

Data Source

PatentUS20260002909A1Qantitative detection method of micro-defects through low-frequency ultrasonic multi-resolution scanning imaging

Publication Date: 2026.01.01 DALIAN UNIV OF TECH

AI summary

In a quantitative detection method of micro-defects through low-frequency ultrasonic multi-resolution scanning imaging, the collected ultrasonic A-type scanning signals are decomposed through split spectrum processing into sub-signals with different center frequencies fi, amplitude imaging is performed on the same sub-signals fi, a defect size di detected by a half of the amplitude of the image is identified, linear fitting is performed on di with fi according to the sound field directivity function, and di corresponding to the slope k=−0.01 of the fitting curve is the quantitative size of the defect.