A new speckle noise suppression technique using cross-correlation of array sub-apertures in ultrasonic NDE of coarse grain materials

Lardner, Timothy; Li, Minghui; Gongzhang, Rui; Gachagan, Anthony

doi:10.1063/1.4789135

Cited by 13 publications

(24 citation statements)

References 0 publications

Supporting

Mentioning

Contrasting

Unclassified

Order By: Relevance

“…In particular, phased array was introduced and several practical techniques based on it have already achieved promising results, such as the widely used Focused B-scan [7], Total Focusing Method (TFM) [7], minimum variance beamforming and adaptive processing [8,9], and spatial diversity based techniques like Spatially Averaged Sub-Array Correlation Imaging (SASACI) [10]. However, phased array techniques are not always available, e.g.…”

Section: Introductionmentioning

confidence: 99%

Robust frequency diversity based algorithm for clutter noise reduction of ultrasonic signals using multiple sub-spectrum phase coherence

Gongzhang¹,

Xiao³

et al. 2014

AIP Conference Proceedings

Self Cite

View full text Add to dashboard Cite

This paper presents a robust frequency diversity based algorithm for clutter reduction in ultrasonic A-scan waveforms. The performance of conventional spectral-temporal techniques like Split Spectrum Processing (SSP) is highly dependent on the parameter selection, especially when the signal to noise ratio (SNR) is low. Although spatial beamforming offers noise reduction with less sensitivity to parameter variation, phased array techniques are not always available. The proposed algorithm first selects an ascending series of frequency bands. A signal is reconstructed for each selected band in which a defect is present when all frequency components are in uniform sign. Combining all reconstructed signals through averaging gives a probability profile of potential defect position. To facilitate data collection and validate the proposed algorithm, Full Matrix Capture is applied on the austenitic steel and high nickel alloy (HNA) samples with 5MHz transducer arrays. When processing A-scan signals with unrefined parameters, the proposed algorithm enhances SNR by 20dB for both samples and consequently, defects are more visible in B-scan images created from the large amount of A-scan traces. Importantly, the proposed algorithm is considered robust, while SSP is shown to fail on the austenitic steel data and achieves less SNR enhancement on the HNA data

show abstract

Section: Introductionmentioning

confidence: 99%

Robust frequency diversity based algorithm for clutter noise reduction of ultrasonic signals using multiple sub-spectrum phase coherence

Gongzhang¹,

Xiao³

et al. 2014

AIP Conference Proceedings

Self Cite

View full text Add to dashboard Cite

show abstract

“…Ultrasonic phased arrays are typically deployed to non-invasively image into solid structures, for example for defect detection in non-destructive evaluation [1,2] or medical diagnosis of patients [3]. Ultrasound imaging has a specific advantage over optical-based methods as it can image into optically opaque materials [1].…”

Section: Introductionmentioning

confidence: 99%

Enhanced phased array imaging through reverberating interfaces

Ingram

Gachagan

Mulholland

et al. 2019

AIP Conference Proceedings

View full text Add to dashboard Cite

A key challenge to achieve non-invasive industrial process analysis is the transmission of information through the vessel wall. Typical non-invasive technologies, such as Raman spectroscopy, require an optically transparent 'window' into the process to acquire the process data. In this work, ultrasonic phased arrays were used to image a dynamic process through planar steel vessel walls into a fluid load. Due to the acoustic impedance mismatch at the steel-fluid interface, only a small fraction of the excitation energy comes back to the receiver in the form of useful echoes from the process. Also, the ultrasonic energy that is not transmitted across the steel-fluid interface reverberates within the vessel wall, masking signals that are reflected from within the process. Here, the ultrasonic array was deployed using Full Matrix Capture (FMC) followed by the Total Focusing Method (TFM) that focusses the ultrasonic beam at every pixel in the image. However, the TFM algorithm is not spatial resolved, leading to multiples of the reverberations interfering throughout the desired image region. To extract the signals corresponding to the process fluid, a method has been developed called the Reverberation Pattern Gain Correction Method (RP-GCM). Firstly, the algorithm uses ray-tracing to predict the path length of reverberations from the steel-fluid interface. The signals in the FMC data set corresponding to those reverberations are then windowed and a gain filter applied, prior to application of the regular TFM process. The RP-GCM has been applied to a simulated FMC data set, developed in PZFlex (OnScale, USA). Initial results demonstrate the effectiveness of this method in separating the vessel reverberations from the ultrasonic echoes of interest relating to the process.

show abstract

“…Whilst imaging performance for NDE applications can be defined by these two indicators, the challenge lies in how to quantify them. Various methodologies have been adopted to compare imaging algorithms [17,[21][22][23][24]; an alternative method is reasoned below by considering detection and characterisation.…”

Section: Imaging Performance Definitionmentioning

confidence: 99%

“…Answering this question however first requires a widely accepted definition of performance and a robust method of measuring it. Various methodologies have previously been adopted to compare imaging algorithms [17,[21][22][23][24], where Signal-to-Noise Ratio (SNR) enhancement is commonly used to convey relative merits. As there exists no widely accepted method, to our knowledge, there remains an opportunity to define an objective method and find a basis for future comparisons.…”

Section: Introductionmentioning

confidence: 99%

A methodology for evaluating detection performance of ultrasonic array imaging algorithms for coarse-grained materials

Pamel

Brett²,

Lowe

2014

IEEE Trans. Ultrason., Ferroelect., Freq. Contr.

View full text Add to dashboard Cite

Abstract-Improving the ultrasound inspection capability for coarse grain metals remains of longstanding interest and is expected to become increasingly important for next generation electricity power plants. Conventional ultrasonic A, B, and C-scans have been found to suffer from strong background noise due to grain scattering which can severely limit the detection of defects. However, in recent years, array probes and Full Matrix Capture (FMC) imaging algorithms have unlocked exciting possibilities for improvements. In order to progress and compare these algorithms we must rely on robust methodologies to quantify their performance. This article proposes such a methodology to evaluate the detection performance of imaging algorithms. For illustration, the methodology is applied to some example data using three FMC imaging algorithms; Total Focusing Method (TFM), Phase Coherent Imaging (PCI), and Decomposition of the Time Reversal Operator with Multiple Scattering Filter (DORT MSF). However it is important to note that this is solely to illustrate the methodology; this article does not attempt the broader investigation of different cases that would be needed to compare the performance of these algorithms in general. The methodology considers the statistics of detection, presenting the detection performance as Probability of Detection (POD) and probability of False Alarm (PFA). A test sample of coarse grained INCONEL 625, manufactured to represent materials used for future power plant components and containing some simple artificial defects, is used to illustrate the method on the candidate algorithms. The data is captured in pulse-echo mode using 64 element array probes at centrefrequencies of 1MHz and 5MHz. In this particular case, it turns out that all three algorithms are shown to perform very similarly when comparing their flaw detection capabilities.

show abstract

A new speckle noise suppression technique using cross-correlation of array sub-apertures in ultrasonic NDE of coarse grain materials

Cited by 13 publications

References 0 publications

Robust frequency diversity based algorithm for clutter noise reduction of ultrasonic signals using multiple sub-spectrum phase coherence

Robust frequency diversity based algorithm for clutter noise reduction of ultrasonic signals using multiple sub-spectrum phase coherence

Enhanced phased array imaging through reverberating interfaces

A methodology for evaluating detection performance of ultrasonic array imaging algorithms for coarse-grained materials

Contact Info

Product

Resources

About