Increased frame rate for plane wave imaging without loss of image quality

Plane Wave Imaging (PWI) has been recently proposed for fast ultrasound inspections in the Non-Destructive-Testing (NDT) field. By using a single (or a reduced number) of plane wave emissions and parallel beamforming in reception, frame rates of hundreds to thousands of images per second can be achieved without significant image quality losses with regard to the Total Focusing Method (TFM) or Phased Array (PA). This work addresses the problem of applying PWI in the presence of arbitrarily shaped interfaces, which is a common problem in NDT. First, the mathematical formulation for generating a plane wave inside a component of arbitrary geometry is given, and the characteristics of the resultant acoustic field are analyzed by simulation, showing plane wavefronts with non-uniform amplitude. Then, an imaging strategy is proposed, accounting for this amplitude effect. Finally, the proposed method is experimentally validated, and its application limits are discussed.

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Two-Dimensional Spatial Coherence for Ultrasonic DMAS Beamforming in Multi-Angle Plane-Wave Imaging

Applied Sciences ◽

10.3390/app9193973 ◽

2019 ◽

Vol 9 (19) ◽

pp. 3973 ◽

Cited By ~ 3

Author(s):

Che-Chou Shen ◽

Pei-Ying Hsieh

Keyword(s):

Image Quality ◽

Plane Wave ◽

Spatial Coherence ◽

P Value ◽

Two Dimensional ◽

One Dimensional ◽

Wave Imaging ◽

Artifact Suppression ◽

Simulation Results ◽

Acquisition Delay

Ultrasonic multi-angle plane-wave (PW) coherent compounding relies on delay-and-sum (DAS) beamforming of two-dimensional (2D) echo matrix in both the dimensions PW transmit angle and receiving channel to construct each image pixel. Due to the characteristics of DAS beamforming, PW coherent compounding may suffer from high image clutter when the number of transmit angles is kept low for ultrafast image acquisition. Delay-multiply-and-sum (DMAS) beamforming exploits the spatial coherence of the receiving aperture to suppress clutter interference. Previous attempts to introduce DMAS beamforming into multi-angle PW imaging has been reported but only in either dimension of the 2D echo matrix. In this study, a novel DMAS operation is proposed to extract the 2D spatial coherence of echo matrix for further improvement of image quality. The proposed 2D-DMAS method relies on a flexibly tunable p value to manipulate the signal coherence in the beamforming output. For p = 2.0 as an example, simulation results indicate that 2D-DMAS outperforms other one-dimensional DMAS methods by at least 9.3 dB in terms of ghost-artifact suppression. Experimental results also show that 2D-DMAS provides the highest improvement in lateral resolution by 32% and in image contrast by 15.6 dB relative to conventional 2D-DAS beamforming. Nonetheless, since 2D-DMAS emphasizes signal coherence more than its one-dimensional DMAS counterparts, it suffers from the most elevated speckle variation and the granular pattern in the tissue background.

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Ultrasound DMAS Beamforming for Estimation of Tissue Speed of Sound in Multi-Angle Plane-Wave Imaging

Applied Sciences ◽

10.3390/app10186298 ◽

2020 ◽

Vol 10 (18) ◽

pp. 6298

Author(s):

Che-Chou Shen ◽

Kuan-Lin Tu

Keyword(s):

Image Quality ◽

Plane Wave ◽

Speed Of Sound ◽

Experimental Dataset ◽

Low Coherence ◽

Wave Imaging ◽

Lateral Width ◽

Pixel Value ◽

Receive Channel ◽

Optimal Beamforming

Various methods have been proposed to estimate the tissue speed of sound (SOS) of propagating medium using the curvature of received channel waveform or the analysis of resultant image quality. In our previous study, baseband delay-multiply-and-sum (DMAS) beamforming methods have been developed for multi-angle plane-wave (PW) imaging which relies on signal coherence among transmit events (Tx-DMAS) or receive channel (Rx-DMAS) or both (2D-DMAS) to suppress low-coherence clutters. In this study, we further extend our DMAS beamforming to quantify the level of signal coherence for determining the average SOS in multi-angle PW imaging. The signal coherence in multi-angle PW imaging is represented as the DMAS coherence factor (DCF) which can be easily estimated from the magnitude ratio of the pixel value of DMAS image to that of DAS image. By searching the beamforming velocity that provides the highest signal coherence of echo matrix, the average tissue SOS of the imaged object can be determined. For the PICMUS experimental dataset, the optimal beamforming velocity (Copt) estimated by the proposed DCF method does provide the best image quality. For the Prodigy dataset, the estimated tissue SOS is 1426 ± 6 m/s which is very close to the actual tissue SOS of 1427 m/s and the estimated SOS also corresponds to the Copt with the minimal −6-dB lateral width and the maximal contrast within an error of 10 m/s. Estimation of tissue SOS in the proposed DCF method is also robust even in the presence of transmit delay error due to deviation of SOS.

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2-D Minimum Variance Based Plane Wave Compounding with Generalized Coherence Factor in Ultrafast Ultrasound Imaging

Sensors ◽

10.3390/s18124099 ◽

2018 ◽

Vol 18 (12) ◽

pp. 4099 ◽

Cited By ~ 4

Author(s):

Yanxing Qi ◽

Yuanyuan Wang ◽

Jinhua Yu ◽

Yi Guo

Keyword(s):

Plane Wave ◽

Ultrasound Imaging ◽

Contrast Ratio ◽

Minimum Variance ◽

Frame Rate ◽

In Vivo Studies ◽

Coherence Factor ◽

Wave Imaging ◽

Phantom Experiments

Plane wave compounding (PWC) is an effective modality for ultrafast ultrasound imaging. It can provide higher resolution and better noise reduction than plane wave imaging (PWI). In this paper, a novel beamformer integrating the two-dimensional (2-D) minimum variance (MV) with the generalized coherence factor (GCF) is proposed to maintain the high resolution and contrast along with a high frame rate for PWC. To specify, MV beamforming is adopted in both the transmitting aperture and the receiving one. The subarray technique is therefore upgraded into the sub-matrix division. Then, the output of each submatrix is used to adaptively compute the GCF using a 2-D fast Fourier transform (FFT). After the 2-D MV beamforming and the 2-D GCF weighting, the final output can be obtained. Results of simulations, phantom experiments, and in vivo studies confirm the advantages of the proposed method. Compared with the delay-and-sum (DAS) beamformer, the full width at half maximum (FWHM) is 90% smaller and the contrast ratio (CR) improvement is 154% in simulations. The over-suppression of desired signals, which is a typical drawback of the coherence factor (CF), can be effectively avoided. The robustness against sound velocity errors is also enhanced.

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Observation and modulation of the dissolution of histotripsy-induced bubble clouds with high-frame rate plane wave imaging

Physics in Medicine and Biology ◽

10.1088/1361-6560/ab1a64 ◽

2019 ◽

Vol 64 (11) ◽

pp. 115012 ◽

Cited By ~ 2

Author(s):

Kenneth B Bader ◽

Samuel A Hendley ◽

Gregory J Anthony ◽

Viktor Bollen

Keyword(s):

Plane Wave ◽

Frame Rate ◽

High Frame Rate ◽

Wave Imaging ◽

Bubble Clouds

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A United Sign Coherence Factor Beamformer for Coherent Plane-Wave Compounding with Improved Contrast

Applied Sciences ◽

10.3390/app10072250 ◽

2020 ◽

Vol 10 (7) ◽

pp. 2250 ◽

Cited By ~ 2

Author(s):

Chen Yang ◽

Yang Jiao ◽

Tingyi Jiang ◽

Yiwen Xu ◽

Yaoyao Cui

Keyword(s):

Image Quality ◽

Plane Wave ◽

Contrast Ratio ◽

Spatial Coherence ◽

Frame Rate ◽

In Vivo Studies ◽

Angular Dimension ◽

One Dimensional ◽

Coherence Factor

In this study, we present a united sign coherence factor beamformer for coherent plane-wave compounding (CPWC). CPWC is capable of reaching an image quality comparable to the conventional B-mode with a much higher frame rate. Conventional coherence factor (CF) based beamformers for CPWC are based on one-dimensional (1D) frameworks, either in the spatial coherence dimension or angular coherence dimension. Both 1D frameworks do not take into account the coherence information of the dimensions of each other. In order to take full advantage of the radio-frequency (RF) data, this paper proposes a united framework containing both spatial and angular information for CPWC. A united sign coherence factor beamformer (uSCF), which combines the conventional sign coherence factor (SCF) and the united framework, is introduced in the paper as well. The proposed beamformer is compared with the conventional 1D SCF beamformers (spatial and angular dimension beamformers) using simulation, phantom and in vivo studies. In the in vivo images, the proposed method improves the contrast ratio (CR) and generalized contrast-to-noise ratio (gCNR) by 197% and 20% over CPWC. Compared with other 1D methods, uSCF also shows an improved contrast and lateral resolution on all datasets.

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Comparison and optimisation of fast array-based ultrasound testing

Insight - Non-Destructive Testing and Condition Monitoring ◽

10.1784/insi.2021.63.4.209 ◽

2021 ◽

Vol 63 (4) ◽

pp. 209-218

Author(s):

K Prashar ◽

M Weston ◽

B Drinkwater

Keyword(s):

Image Quality ◽

Imaging Techniques ◽

Frame Rate ◽

Destructive Testing ◽

Full Matrix ◽

Wave Imaging ◽

Scan Speed ◽

Major Loss ◽

Intuitive View ◽

Imaging Algorithms

Phased array ultrasonic testing (PAUT) is now a widely used technique in industry for non-destructive testing. Arrays offer an intuitive view of the interior of a component from which geometric features and defects can be observed. Arrays also offer detailed information about the nature and extent of any defects. In recent years, full matrix capture (FMC) and the total focusing method (TFM) have attracted significant interest due to the high resolution of the images possible throughout an inspection volume. Due to the requirement of transmitting on each element separately, full matrix capture-based imaging techniques limit the maximum frame rate and scan speed achievable. Recently, to increase the speed of data acquisition, new techniques such as plane wave imaging (PWI) and virtual source aperture (VSA) have been introduced. They allow a significant reduction in the number of firings to be achieved without contributing to any major loss of image quality. In this paper, an in-depth comparison of these techniques using a hybrid linear system model and the analysis of experimental data is performed to assess the image quality of these emerging imaging algorithms and hence identify the optimal parameters for faster imaging.

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Micro Non-Uniform Linear Array (MNULA) for Ultrasound Plane Wave Imaging

Sensors ◽

10.3390/s21020640 ◽

2021 ◽

Vol 21 (2) ◽

pp. 640

Author(s):

Yujia Tang ◽

Zhangjian Li ◽

Yaoyao Cui ◽

Chen Yang ◽

Jiabing Lv ◽

...

Keyword(s):

Plane Wave ◽

Linear Array ◽

Near Field ◽

Uniform Linear Array ◽

Imaging Technology ◽

Linear Arrays ◽

Imaging Quality ◽

Imaging Results ◽

Wave Imaging ◽

Laboratory Technology

Ultrasound plane wave imaging technology has been applied to more clinical situations than ever before because of its rapid imaging speed and stable imaging quality. Most transducers used in plane wave imaging are linear arrays, but their structures limit the application of plane wave imaging technology in some special clinical situations, especially in the endoscopic environment. In the endoscopic environment, the size of the linear array transducer is strictly miniaturized, and the imaging range is also limited to the near field. Meanwhile, the near field of a micro linear array has serious mutual interferences between elements, which is against the imaging quality of near field. Therefore, we propose a new structure of a micro ultrasound linear array for plane wave imaging. In this paper, a theoretical comparison is given through sound field and imaging simulations. On the basis of primary work and laboratory technology, micro uniform and non-uniform linear arrays were made and experimented with the phantom setting. We selected appropriate evaluation parameters to verify the imaging results. Finally, we concluded that the micro non-uniform linear array eliminated the artifacts better than the micro uniform linear array without the additional use of signal processing methods, especially for target points in the near-field. We believe this study provides a possible solution for plane wave imaging in cramped environments like endoscopy.

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A Color-Doppler Shear-Wave-Imaging Phase-reconstruction Method Using Four Color Flow Images

Ultrasonic Imaging ◽

10.1177/0161734616680985 ◽

2016 ◽

Vol 39 (3) ◽

pp. 172-188

Author(s):

Naoki Sunaguchi ◽

Yoshiki Yamakoshi ◽

Takahito Nakajima

Keyword(s):

Image Quality ◽

Shear Wave ◽

Initial Phase ◽

Color Doppler ◽

Reconstruction Method ◽

Phase Reconstruction ◽

Color Flow ◽

Shear Wave Imaging ◽

Wave Imaging ◽

Phase Map

This study investigates shear wave phase map reconstruction using a limited number of color flow images (CFIs) acquired with a color Doppler ultrasound imaging instrument. We propose an efficient reconstruction method to considerably reduce the number of CFIs required for reconstruction and compare this method with Fourier analysis-based color Doppler shear wave imaging. The proposed method uses a two-step phase reconstruction process, including an initial phase map derived from four CFIs using an advanced iterative algorithm of optical interferometry. The second step reduces phase artifacts in the initial phase map using an iterative correction procedure that cycles between the Fourier and inverse Fourier domains while imposing directional filtering and total variation regularization. We demonstrate the efficacy of this method using synthetic and experimental data of a breast phantom and human breast tissue. Our results show that the proposed method maintains image quality and reduces the number of CFIs required to four; previous methods have required at least 32 CFIs to achieve equivalent image quality. The proposed method is applicable to real-time shear wave elastography using a continuous shear wave produced by a mechanical vibrator.

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DMAS Beamforming with Complementary Subset Transmit for Ultrasound Coherence-Based Power Doppler Detection in Multi-Angle Plane-Wave Imaging

Sensors ◽

10.3390/s21144856 ◽

2021 ◽

Vol 21 (14) ◽

pp. 4856

Author(s):

Che-Chou Shen ◽

Yen-Chen Chu

Keyword(s):

Plane Wave ◽

Power Doppler ◽

P Value ◽

Low Resolution ◽

Ensemble Averaging ◽

Stationary Tissue ◽

Wave Imaging ◽

Acquisition Delay ◽

Complementary Subset ◽

Low Resolution Images

Conventional ultrasonic coherent plane-wave (PW) compounding corresponds to Delay-and-Sum (DAS) beamforming of low-resolution images from distinct PW transmit angles. Nonetheless, the trade-off between the level of clutter artifacts and the number of PW transmit angle may compromise the image quality in ultrafast acquisition. Delay-Multiply-and-Sum (DMAS) beamforming in the dimension of PW transmit angle is capable of suppressing clutter interference and is readily compatible with the conventional method. In DMAS, a tunable p value is used to modulate the signal coherence estimated from the low-resolution images to produce the final high-resolution output and does not require huge memory allocation to record all the received channel data in multi-angle PW imaging. In this study, DMAS beamforming is used to construct a novel coherence-based power Doppler detection together with the complementary subset transmit (CST) technique to further reduce the noise level. For p = 2.0 as an example, simulation results indicate that the DMAS beamforming alone can improve the Doppler SNR by 8.2 dB compared to DAS counterpart. Another 6-dB increase in Doppler SNR can be further obtained when the CST technique is combined with DMAS beamforming with sufficient ensemble averaging. The CST technique can also be performed with DAS beamforming, though the improvement in Doppler SNR and CNR is relatively minor. Experimental results also agree with the simulations. Nonetheless, since the DMAS beamforming involves multiplicative operation, clutter filtering in the ensemble direction has to be performed on the low-resolution images before DMAS to remove the stationary tissue without coupling from the flow signal.

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