3B-1 Flaw Detection in Layered Media Based on Parametric Modeling of Overlapping Ultrasonic Echoes

Author

Hagglund, Fredrik ; Martinsson, Jesper ; Carlson, Johan E.

Author_Institution

Dept. of Comput. Sci. & Electr. Eng., Lulea Univ. of Technol.

fYear

2006

fDate

2-6 Oct. 2006

Firstpage

136

Lastpage

139

Abstract

In materials consisting of several thin layers, multiple reflections within the structure give rise to received ultrasonic signals composed of overlapping echoes. In this paper we present a parametric model that can be used to decompose such signals into the individual reflections. We derive a maximum likelihood estimator for the the model parameters, which are then used in a generalized likelihood ratio test (GLRT) to detect flaws in multi-layered structures. We show with simulations how the presence of a thin bonding layer in a three-layer structure can be detected. The probability of detection is shown to be ap96%, for a signal-to-noise ratio (SNR) of 15 dB and a probability of false alarm of 5 %

Keywords

flaw detection; maximum likelihood estimation; multilayers; ultrasonic materials testing; ultrasonic reflection; flaw detection; generalized likelihood ratio test; maximum likelihood estimator; multilayered structure; multiple reflection; overlapping ultrasonic echoe; parametric modeling; signal-to-noise ratio; thin bonding layer; Bonding; Detectors; Maximum likelihood detection; Maximum likelihood estimation; Nonhomogeneous media; Parametric statistics; Reflection; Signal to noise ratio; Student members; Testing;

fLanguage

English

Publisher

ieee

Conference_Titel

Ultrasonics Symposium, 2006. IEEE

Conference_Location

Vancouver, BC

ISSN

1051-0117

Print_ISBN

1-4244-0201-8

Electronic_ISBN

1051-0117

Type

conf

DOI

10.1109/ULTSYM.2006.47

Filename

4151903