Photoacoustic correlation signal-to-noise ratio enhancement by coherent averaging and optical waveform optimization

Telenkov, Sergey A.; Alwi, Rudolf; Mandelis, Andreas

doi:10.1063/1.4825034

Cited by 28 publications

(23 citation statements)

References 11 publications

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“…The FD pulse compression technique analyzes the entire record of a relatively long signal to identify the presence of signals with characteristics of the known reference signal, while pulse-based PA performs a single-point time-resolved measurement. 67,68,85 There are many variables involved in optical modulation by a chirp waveform. For optimization of optical LFM waveform design in the CW-based PA modality, Lashkari and Mandelis 48 suggested doing so with respect to the maximum SNR of the processed signal.…”

Section: Generation Of Conventional Cw-based Pa Signalsmentioning

confidence: 99%

Review of the state of the art in cardiovascular endoscopy imaging of atherosclerosis using photoacoustic techniques with pulsed and continuous-wave optical excitations

Choi

Mandelis

2019

J. Biomed. Opt.

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Review of the state of the art in cardiovascular endoscopy imaging of atherosclerosis using photoacoustic techniques with pulsed and continuous-wave optical excitations," J.Abstract. Intravascular photoacoustics (IV-PA) is an emerging atherosclerosis imaging modality that provides chemical-specific optical information of arterial walls with acoustic depth penetration and resolution. As lipid composition of atherosclerotic plaques is considered to be one of the primary indicators for plaque vulnerability, many IV-PA applications are calibrated so as to target plaque necrotic cores. Based on the mode of optical excitation and the corresponding signal processing technique, IV-PA is categorized into two different modalities. The pulse-based IV-PA has been the universal IV-PA imaging mode with its high peak power and straightforward time-domain signal processing technique. As an alternative, the low power continuous-wave (CW)-based IV-PA has been under intense development as a radar-like frequency-domain signal processing modality. The two state-of-the-art types of IV-PA are reviewed in terms of their physics and imaging capabilities, with major emphasis on frequency-swept CW-based IV-PA that has been recently introduced in the field. © The Authors. Published by SPIE under a Creative Commons Attribution 4.0 Unported License. Distribution or reproduction of this work in whole or in part requires full attribution of the original publication, including its DOI.

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Section: Generation Of Conventional Cw-based Pa Signalsmentioning

confidence: 99%

Review of the state of the art in cardiovascular endoscopy imaging of atherosclerosis using photoacoustic techniques with pulsed and continuous-wave optical excitations

Choi

Mandelis

2019

J. Biomed. Opt.

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“…For simplicity, we henceforth assume that the amplitude A is unity. Equation (1) is the simplest and most popular FM chirp; however, alternatives to this have also been employed, for instance, nonlinear frequency sweeps [26] or square carrier waveforms [27], [28]. A GC is defined as a pair of N-bit length binary sequences, A(k)(k = 0, 1, .…”

Section: Design Of Weakly Correlated (Mismatched) Waveformsmentioning

confidence: 99%

“…Coherent averaging indicates that the phases of the individual signals affect the averaged value. The detailed description can be found elsewhere [28], [32]. Fig.…”

Section: Cross-correlation Reduction Between Mismatched Signalsmentioning

confidence: 99%

“…This arrangement facilitated an automated sweep through the subarrays and therefore provided a fairly fast acquisition rate with minimum complexity. The LabView program was employed to collect the response waveform of each subarray section and average the waveforms coherently [28]. Afterward, the CC signals of all channels with the transmitted signals were calculated.…”

Section: Instrumentation and System Implementationmentioning

confidence: 99%

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High-Frame-Rate Synthetic Aperture Ultrasound Imaging Using Mismatched Coded Excitation Waveform Engineering: A Feasibility Study

Lashkari

Zhang

Mandelis

2016

IEEE Trans. Ultrason., Ferroelect., Freq. Contr.

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Mismatched coded excitation (CE) can be employed to increase the frame rate of synthetic aperture ultrasound imaging. The high autocorrelation and low cross correlation (CC) of transmitted signals enables the identification and separation of signal sources at the receiver. Thus, the method provides B-mode imaging with simultaneous transmission from several elements and capability of spatial decoding of the transmitted signals, which makes the imaging process equivalent to consecutive transmissions. Each transmission generates its own image and the combination of all the images results in an image with a high lateral resolution. In this paper, we introduce two different methods for generating multiple mismatched CEs with an identical frequency bandwidth and code length. Therefore, the proposed families of mismatched CEs are able to generate similar resolutions and signal-to-noise ratios. The application of these methods is demonstrated experimentally. Furthermore, several techniques are suggested that can be used to reduce the CC between the mismatched codes.

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“…Signal averaging is commonly used to improve the SNR of PA images when the ultrasound transducer, light source, and target are fixed in the same position [13], [16], [18]. However, this type of averaging reduces frame rates for real-time imaging applications and has limited ability to reduce statistically dependent background noise [19], [20].…”

Section: Introductionmentioning

confidence: 99%

Spatial Angular Compounding ofPhotoacoustic Images

Kang

Bell

Guo

et al. 2016

IEEE Trans. Med. Imaging

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Photoacoustic (PA) images utilize pulsed lasers and ultrasound transducers to visualize targets with higher optical absorption than the surrounding medium. However, they are susceptible to acoustic clutter and background noise artifacts that obfuscate biomedical structures of interest. We investigated three spatial-angular compounding methods to improve PA image quality for biomedical applications, implemented by combining multiple images acquired as an ultrasound probe was rotated about the elevational axis with the laser beam and target fixed. Compounding with conventional averaging was based on the pose information of each PA image, while compounding with weighted and selective averaging utilized both the pose and image content information. Weighted-average compounding enhanced PA images with the least distortion of signal size, particularly when there were large (i.e. 2.5 mm and 7°) perturbations from the initial probe position. Selective-average compounding offered the best improvement in image quality with up 181, 1665, and 1568 times higher contrast, CNR, and SNR, respectively, compared to the mean values of individual PA images. The three presented spatial compounding methods have promising potential to enhance image quality in multiple photoacoustic applications.

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Photoacoustic correlation signal-to-noise ratio enhancement by coherent averaging and optical waveform optimization

Cited by 28 publications

References 11 publications

Review of the state of the art in cardiovascular endoscopy imaging of atherosclerosis using photoacoustic techniques with pulsed and continuous-wave optical excitations

Review of the state of the art in cardiovascular endoscopy imaging of atherosclerosis using photoacoustic techniques with pulsed and continuous-wave optical excitations

High-Frame-Rate Synthetic Aperture Ultrasound Imaging Using Mismatched Coded Excitation Waveform Engineering: A Feasibility Study

Spatial Angular Compounding ofPhotoacoustic Images

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