Higher-order spatial correlation coefficients of ultrasonic backscattering signals using partial cross-correlation analysis

Yongfeng Song, Christopher Kube, Jie Zhang, Xiongbing Li

Research output: Contribution to journalArticle (Academic Journal)peer-review

2 Citations (Scopus)
31 Downloads (Pure)

Abstract

The spatial correlation properties of ultrasonic backscattering signals in random media have important implications. For example, they can be used for microstructural characterization and flaw detection in engineering materials. However, the traditional spatial correlation coefficient (SCC) is only a leading order quantity that does not capture the true spatial correlations of random media. This is caused by neglecting confounding variables such as non-zero means or other non-zero odd-order moments. Here, the SCC is generalized from zeroth- to general-order through partial cross-correlation analysis. A series of indicators are defined to quantify the SCC curve at zero time lag, and the maximum time shift curve, which are both functions of lateral separation between two sensor positions. A stainless-steel specimen and a focused ultrasonic transducer are used to verify the method. Scattering measurements show that the higher-order SCC can consistently capture spatial correlations whereas the zeroth-order SCC is inadequate. The zeroth-order SCC is shown to predict a step size that can be more than six times too large. Thus, the present method can provide better understanding of statistical correlations and conditions to measure uncorrelated backscattering signals.
Original languageEnglish
Article number757 (2020)
Pages (from-to)757-768
Number of pages12
JournalJournal of the Acoustical Society of America
Volume147
Issue number2
Early online date5 Feb 2020
DOIs
Publication statusE-pub ahead of print - 5 Feb 2020

Fingerprint Dive into the research topics of 'Higher-order spatial correlation coefficients of ultrasonic backscattering signals using partial cross-correlation analysis'. Together they form a unique fingerprint.

Cite this