Use of a Chirp-coded Excitation Method in Order to Improve Geometrical and Acoustical Measurements in Wood Specimen

Lasaygues, Philippe; Arciniegas, Andres; Brancheriau, Loïc

doi:10.1016/j.phpro.2015.08.083

Cited by 2 publications

(3 citation statements)

References 12 publications

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“…When a recognizable signature is sent through the media, such as chirp signal, input and output signals delay time can be obtained using cross-correlation [26,27,28]. The maximum value for the crosscorrelation function between two signals indicates their delay time.…”

Section: Cross-correlationmentioning

confidence: 99%

“…Automatic methods for detecting first arrivals have been proposed, including pickers based on the Akaike information criteria (AIC) [23,24] and the Hinkley criteria [25]. Alternatives include the transmission of encoded waveforms, such as the chirp-coded excitation method, where a recognizable signature is sent through the media and the TOF is estimated using a cross-correlation function [26,27,28]. In consideration of the wide range of signals and TOF detection techniques, the choice of pa-…”

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confidence: 99%

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Accuracy on the Time-of-Flight Estimation for Ultrasonic Waves Applied to Non-Destructive Evaluation of Standing Trees: A Comparative Experimental Study

Espinosa¹,

Bacca²,

Prieto³

et al. 2018

Acta Acustica united with Acustica

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Time-of-flight measurement is a critical step to per-2 form ultrasonic non-destructive testing of standing 3 trees, with direct influence on the precision of de-4 fect detection. Aiming to increase the accuracy on 5 the estimation, the characteristics of the ultrasonic 6 measurement chain should be adapted to the con-7 straints of wood testing in living condition. This 8 study focused on the excitation signal parameters, 9 such as shape, temporal duration, and frequency re-10 sponse, and then the selection of a suitable time-11 of-flight determination technique. A standing plane 12 tree was tested, placing ultrasonic receivers at four 13 different positions, with five different excitation sig-14 nals and three time-of-flight detection methods. The 15 proposed ultrasonic chain of measurement resulted in 16 high signal-to-noise ratios in received signals for all 17 configurations. A time-frequency analysis was used 18 to determine the power distribution in the frequency 19 domain, showing that only chirp signal could concen-20 trate the power around the resonant frequency of the 21 sensor. Threshold and Akaike information criterion 22 method performed similar for impulsive signals with 23 decreasing uncertainty as sensor position approached 24 to the radial direction. Those two methods failed to 25 accurate determine time-of-flight for Gaussian pulse 26 and chirp signals. Cross-correlation was only suitable 27 for the chirp signal, presenting the lower uncertainty 28 values among all configurations.

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Section: Cross-correlationmentioning

confidence: 99%

mentioning

confidence: 99%

Accuracy on the Time-of-Flight Estimation for Ultrasonic Waves Applied to Non-Destructive Evaluation of Standing Trees: A Comparative Experimental Study

Espinosa¹,

Bacca²,

Prieto³

et al. 2018

Acta Acustica united with Acustica

Self Cite

View full text Add to dashboard Cite

show abstract

“…Depending on the wavelength, this causes an overlap between the wave packets that results in a significant loss of information. Lasaygues et al [11] showed that the duration of the chirp signal had a weak influence on the calculation of physical parameters such as the thickness and the ultrasonic wave velocity.…”

Section: Introductionmentioning

confidence: 99%

Accuracy of coded excitation methods for measuring the time of flight: Application to ultrasonic characterization of wood samples

et al. 2018

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Ultrasound computed tomography (USCT) using the transmission mode is a way to detect and assess the extent of decay in wood structures. The resolution of the ultrasonic image is closely related to the different anatomical features of wood. The complexity of the wave propagation process generates complex signals consisting of several wave packets with different signatures. Wave paths, depth dependencies, wave velocities or attenuations are often difficult to interpret. For this kind of assessment, the focus is generally on signal pre-processing. Several approaches have been used so far including filtering, spectrum analysis and a method involving deconvolution using a characteristic transfer function of the experimental device. However, all these approaches may be too sophisticated and/or unstable. The alternative methods proposed in this work are based on coded excitation, which makes it possible to process both local and general information available such as frequency and time parameters. Coded excitation is based on the filtering of the transmitted signal using a suitable electric input signal. The aim of the present study was to compare two coded-excitation methods, a chirp- and a wavelet-coded excitation method, to determine the time of flight of the ultrasonic wave, and to investigate the feasibility, the robustness and the precision of the measurement of geometrical and acoustical properties in laboratory conditions. To obtain control experimental data, the two methods were compared with the conventional ultrasonic pulse method. Experiments were conducted on a polyurethane resin sample and two samples of different wood species using two 500 kHz-transducers. The relative errors in the measurement of thickness compared with the results of caliper measurements ranged from 0.13% minimum for the wavelet-coded excitation method to 2.3% maximum for the chirp-coded excitation method. For the relative errors in the measurement of ultrasonic wave velocity, the coded excitation methods showed differences ranging from 0.24% minimum for the wavelet-coded excitation method to 2.62% maximum for the chirp-coded excitation method. Methods based on coded excitation algorithms thus enable accurate measurements of thickness and ultrasonic wave velocity in samples of wood species.

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Use of a Chirp-coded Excitation Method in Order to Improve Geometrical and Acoustical Measurements in Wood Specimen

Cited by 2 publications

References 12 publications

Accuracy on the Time-of-Flight Estimation for Ultrasonic Waves Applied to Non-Destructive Evaluation of Standing Trees: A Comparative Experimental Study

Accuracy on the Time-of-Flight Estimation for Ultrasonic Waves Applied to Non-Destructive Evaluation of Standing Trees: A Comparative Experimental Study

Accuracy of coded excitation methods for measuring the time of flight: Application to ultrasonic characterization of wood samples

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