Target-detection and localization in multilayered media through mixed TR–RTM method

Abstract

The problem of target detection and localization in layered media can be solved by the mixed TR–RTM. The highlight of this paper is on multilayer media, where the target is harder to detect than in double-layered media, due to the interference of multiple interface reflection signals. The core idea of the TR–RTM mixed method, namely the RTM isochronism principle, is applied for the three cases. Typically, a target under a TR–RTM process can form a mountain-like acoustic field distribution. For the interface whose reflected signal is an interference, the acoustic field distribution is disordered and inhomogeneous, with a smaller amplitude. The TR–RTM greatly improves the signal-to-interference ratio, where the position of the summit is the just position of the target, thus, detecting and localizing the target.

KEYWORDS:

• Time reversal
• reversed-time migration
• ultrasonic test
• layered media

2010 MATHEMATICS SUBJECT CLASSIFICATIONS:

• 00
• 60

Disclosure statement

No potential conflict of interest was reported by the author(s).

Additional information

Funding

This work is supported by National Natural Science Foundation of China [Grant Number 12004018 and 11772013], Project funded by China Postdoctoral Science Foundation [2019M660372], the State Key Laboratory of Acoustics, Chinese Academy of Sciences, Beijing Postdoctoral Research Foundation.