Barker coded excitation with linear frequency modulated carrier for ultrasonic imaging

Fu, Jing; Wang, Gang; Huang, Qinghua; Ji, Fei; Feng, Yuanhua

doi:10.1016/j.bspc.2014.06.004

Cited by 12 publications

(6 citation statements)

References 20 publications

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“…Although the transducer with a centre frequency of 500 kHz is used in this experiment, the 13-bit sinusoid-Barker code excitation can still be extended to a high-frequency system to improve the spatial resolution. In addition, by combining the linear frequency modulation with the Barker coded sequence, a higher SNR with good spatial resolution is obtained in B-mode sonography, [39] which might be used to improve the performance of MAET measurement for biological tissues in further studies.…”

Section: Discussionmentioning

confidence: 99%

Performance improvement of magneto-acousto-electrical tomography for biological tissues with sinusoid-Barker coded excitation

Yan

et al. 2018

Chinese Phys. B

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By combining magnetics, acoustics and electrics, the magneto-acoustic-electrical tomography (MAET) proves to possess the capability of differentiating electrical impedance variation and thus improving the spatial resolution. However, the signal-to-noise ratio (SNR) of the collected MAET signal is still unsatisfactory for biological tissues with low-level electrical conductivity. In this study, the formula of MAET measurement with sinusoid-Barker coded excitation is derived and simplified for a planar piston transducer. Numerical simulations are conducted for a four-layered gel phantom with the 13-bit sinusoid-Barker coded excitation, and the performances of wave packet recovery with side-lobe suppression are improved by using the mismatched compression filter, which is also demonstrated by experimentally measuring a three-layered gel phantom. It is demonstrated that comparing with the single-cycle sinusoidal excitation, the amplitude of the driving signal can be reduced greatly with an SNR enhancement of 10 dB using the 13-bit sinusoid-Barker coded excitation. The amplitude and polarity of the wave packet filtered from the collected MAET signal can be used to achieve the conductivity derivative at the tissue boundary. In this study, we apply the sinusoid-Barker coded modulation method and the mismatched suppression scheme to MAET measurement to ensure the safety for biological tissues with improved SNR and spatial resolution, and suggest the potential applications in biomedical imaging.

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Section: Discussionmentioning

confidence: 99%

Performance improvement of magneto-acousto-electrical tomography for biological tissues with sinusoid-Barker coded excitation

Yan

et al. 2018

Chinese Phys. B

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“…The frequency-modulated signal with 8 µs length, 1 MHz center frequency, and 2 MHz bandwidth is used as a single code element to constitute the linear frequency modulation Barker (LFMB) code. The total length of the LFMB code is 104 µs, and the LFMB code is used in simulation to improve the accuracy of time delay calculations, which is expressed as [ 57 ]

…”

Section: Application Of Pulse Compression In Transcranial Phased Arra...mentioning

confidence: 99%

Transcranial Ultrasonic Focusing by a Phased Array Based on Micro-CT Images

Yin,

Yan,

Huang

et al. 2023

Sensors

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In this paper, we utilize micro-computed tomography (micro-CT) to obtain micro-CT images with a resolution of 60 μm and establish a micro-CT model based on the k-wave toolbox, which can visualize the microstructures in trabecular bone, including pores and bone layers. The transcranial ultrasound phased array focusing field characteristics in the micro-CT model are investigated. The ultrasonic waves are multiply scattered in skull and time delays calculations from the transducer to the focusing point are difficult. For this reason, we adopt the pulse compression method and the linear frequency modulation Barker code to compute the time delay and implement phased array focusing in the micro-CT model. It is shown by the simulation results that ultrasonic loss is mainly caused by scattering from the microstructures of the trabecular bone. The ratio of main and side lobes of the cross-correlation calculation is improved by 5.53 dB using the pulse compression method. The focusing quality and the calculation accuracy of time delay are improved. Meanwhile, the beamwidth at the focal point and the sound pressure amplitude decrease with the increase in the signal frequency. Focusing at different depths indicates that the beamwidth broadens with the increase in the focusing depth, and beam deflection focusing maintains good consistency in the focusing effect at a distance of 9 mm from the focal point. This indicates that the phased-array method has good focusing results and focus tunability in deep cranial brain. In addition, the sound pressure at the focal point can be increased by 8.2% through amplitude regulation, thereby enhancing focusing efficiency. The preliminary experiment verification is conducted with an ex vivo skull. It is shown by the experimental results that the phased array focusing method using pulse compression to calculate the time delay can significantly improve the sound field focusing effect and is a very effective transcranial ultrasound focusing method.

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“…Hence, it is modulated with a carrier using the BPSK modulation technique. The transmitted signal e[n] can be obtained as [13]:…”

Section: B Barker Code Encoding and Pulse Compression Schemementioning

confidence: 99%

“…To improve ultrasonic imaging quality in terms of axial resolution and SNR, a new Barker coded excitation based on a linear chirp carrier was proposed in [13]. Hereafter, the encoding excitation technique was introduced in other ultrasonic detection applications.…”

Section: Introductionmentioning

confidence: 99%

An Adaptive Peak Detection Method for Inspection of Breakages in Long Rails by Using Barker Coded UGW

et al. 2020

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For a broken rail detection system based on ultrasonic guided waves (UGW), the multimodal and dispersion of UGW degrade signal-to-noise ratio (SNR) and range resolution. To improve SNR of the received signals and range resolution, the pulse compression technique based on 13-bit Barker code is presented in this work. Through a PSpice model of the pitch-catch setup, as well as performing field tests, it is shown that coded UGW signals can efficiently improve SNR by 5 dB and have strong noise immunity. As the detection distance increases, the mainlobe width increases linearly while the sidelobe peak levels remain basically unchanged. In addition, to correctly and quickly identify the corresponding transmissions at the receivers, an adaptive peak detection algorithm is proposed, which is based on a digital bandpass tracking filter, moving averaging filters and Hilbert transform. By using some field tests under different detection distances, it is found that compared to the previous works, the proposed adaptive peak detection algorithm has stronger robustness and better anti-noise performance. In addition, the proposed method is easy to integrate into a real-time detection system by proper software design. INDEX TERMS Peaks detection, barker code, pulse compression, long rail breakages detection, UGW.

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Barker coded excitation with linear frequency modulated carrier for ultrasonic imaging

Cited by 12 publications

References 20 publications

Performance improvement of magneto-acousto-electrical tomography for biological tissues with sinusoid-Barker coded excitation

Performance improvement of magneto-acousto-electrical tomography for biological tissues with sinusoid-Barker coded excitation

Transcranial Ultrasonic Focusing by a Phased Array Based on Micro-CT Images

An Adaptive Peak Detection Method for Inspection of Breakages in Long Rails by Using Barker Coded UGW

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