Detection of echoes in noisy environments for multilayer structure characterization

Digital signal processing techniques set up to detect echoes in noisy environments and to thus carry out thickness measurements in thin multilayer structures are discussed. In particular, the cepstrum and the segmented chirp Z-transform are analyzed and compared, highlighting their performances in relation to noise characteristics. A suitable operating procedure was set up, based on an initial emulation phase in which simulated signals are considered, followed by a second phase in which signals were processed. The results show that optimum performances can be achieved by using the segmented chirp Z-transform together with a high flexible window. >

[1]  Chiou-Shiun Chen,et al.  Cepstral processing using spread spectra for cable diagnostics , 1981, IEEE Transactions on Instrumentation and Measurement.

[2]  Reinhold Ludwig,et al.  The chirp-Z transform applied to adhesively bonded structures , 1991 .

[3]  J. Ophir,et al.  Optimization of speed-of-sound estimation from noisy ultrasonic signals , 1989, IEEE Transactions on Ultrasonics, Ferroelectrics and Frequency Control.

[4]  L. Verrazzani,et al.  Spectral characterization of tissues microstructure by ultrasounds: a stochastic approach , 1990, IEEE Transactions on Ultrasonics, Ferroelectrics and Frequency Control.

[5]  D.P. Skinner,et al.  The cepstrum: A guide to processing , 1977, Proceedings of the IEEE.

[6]  L. Bluestein.  A linear filtering approach to the computation of discrete Fourier transform , 1970 .

[7]  Tapan K. Sarkar,et al.  Enhancement of Poles in Spectral Analysis , 1981, IEEE Transactions on Geoscience and Remote Sensing.

[8]  R.W. Schafer,et al.  Digital representations of speech signals , 1975, Proceedings of the IEEE.

[9]  T. T. Wang,et al.  The segmented chirp Z-transform and its application in spectrum analysis , 1990 .

[10]  F. Tseng,et al.  Design of array and line-source antennas for Taylor patterns with a null , 1979 .

[11]  L. Rabiner,et al.  The chirp z-transform algorithm and its application , 1969 .

[12]  D J Coleman,et al.  In vivo choroidal thickness measurement. , 1979, American journal of ophthalmology.

[13]  L. Van Biesen,et al.  High accuracy location of faults on electrical lines using digital signal processing , 1990 .

[14]  Cepstrum technique for multilayer structure characterization , 1990, IEEE Symposium on Ultrasonics.

[15]  S. Tane,et al.  The microscopic biometry of the thickness of human retina, choroid and sclera by ultrasound , 1987 .

[16]  A. Nuttall.  Some windows with very good sidelobe behavior , 1981 .

[17]  P. Daponte,et al.  On the use of a special window in power harmonic analysis , 1990 .

[18]  F. Harris.  On the use of windows for harmonic analysis with the discrete Fourier transform , 1978, Proceedings of the IEEE.

[19]  D. A. Seggie,et al.  Deterministic approach towards ultrasound speckle reduction , 1987 .

[20]  Tapan K. Sarkar,et al.  A novel window for harmonic analysis , 1981 .

[21]  J. C. Rogers,et al.  Measurement of acoustic reflection coefficients using the power cepstrum , 1986, IEEE Transactions on Instrumentation and Measurement.

[22]  P.L. Carson,et al.  What a Hospital Physicist Needs in a Transducer Characterization Standard: Are Tissue-Equivalent Test Objects Necessary? , 1979, IEEE Transactions on Sonics and Ultrasonics.

[23]  F. Dunn,et al.  In Vivo Measurement of Thickness or of Speed of Sound in Biological Tissue Structures , 1983, IEEE Transactions on Sonics and Ultrasonics.

[24]  Donald G. Childers,et al.  Signal detection and extraction by cepstrum techniques , 1972, IEEE Trans. Inf. Theory.