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

Sensors ◽  
2018 ◽  
Vol 18 (12) ◽  
pp. 4099 ◽  
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.

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

2020 ◽  
Vol 10 (7) ◽  
pp. 2250 ◽  
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.

scholarly journals High Resolution, High Contrast Beamformer Using Minimum Variance and Plane Wave Nonlinear Compounding with Low Complexity

Sensors ◽  
2021 ◽  
Vol 21 (2) ◽  
pp. 394
Author(s):  
Xin Yan ◽  
Yanxing Qi ◽  
Yinmeng Wang ◽  
Yuanyuan Wang
Keyword(s):  
Plane Wave ◽  
Dimensional Space ◽  
Contrast Ratio ◽  
Low Complexity ◽  
Minimum Variance ◽  
Frame Rate ◽  
Channel Noise ◽  
Length Estimation ◽  
Lower Dimensional Space

The plane wave compounding (PWC) is a promising modality to improve the imaging quality and maintain the high frame rate for ultrafast ultrasound imaging. In this paper, a novel beamforming method is proposed to achieve higher resolution and contrast with low complexity. A minimum variance (MV) weight calculated by the partial generalized sidelobe canceler is adopted to beamform the receiving array signals. The dimension reduction technique is introduced to project the data into lower dimensional space, which also contributes to a large subarray length. Estimation of multi-wave receiving covariance matrix is performed and then utilized to determine only one weight. Afterwards, a fast second-order reformulation of the delay multiply and sum (DMAS) is developed as nonlinear compounding to composite the beamforming output of multiple transmissions. Simulations, phantom, in vivo, and robustness experiments were carried out to evaluate the performance of the proposed method. Compared with the delay and sum (DAS) beamformer, the proposed method achieved 86.3% narrower main lobe width and 112% higher contrast ratio in simulations. The robustness to the channel noise of the proposed method is effectively enhanced at the same time. Furthermore, it maintains a linear computational complexity, which means that it has the potential to be implemented for real-time response.

scholarly journals Converting Coherence to Signal-to-noise Ratio for Enhancement of Adaptive Ultrasound Imaging

2019 ◽  
Vol 42 (1) ◽  
pp. 27-40 ◽  
Author(s):  
Hideyuki Hasegawa ◽  
Ryo Nagaoka
Keyword(s):  
Ultrasound Imaging ◽  
Spatial Resolution ◽  
Signal To Noise Ratio ◽  
Frame Rate ◽  
Signal To Noise ◽  
High Frame Rate ◽  
Ultrasonic Echo ◽  
Wave Imaging ◽  
Noise Ratio ◽  
Phantom Experiments

High-frame-rate ultrasound is an emerging technique for functional ultrasound imaging. However, the lateral spatial resolution and contrast in high-frame-rate ultrasound with an unfocused transmit beam are inherently lower than those in conventional ultrasonic imaging based on the line-by-line acquisition using a focused ultrasonic beam because of the low directivity of the transmit beam. Coherence-based beamforming methods were introduced in ultrasound imaging for improvement of image quality. Such methods improve the lateral spatial resolution using the coherence among ultrasonic echo signals received by individual transducer elements. In this study, a new method based on the signal-to-noise ratio (SNR) among the element echo signals was developed for enhancement of the effect of the coherence factor (CF), which was previously developed for improvement in spatial resolution and contrast. In the proposed method, a new factor, namely, SNR factor, was introduced, and the relationship between the previously developed CF and SNR factor was discussed. The proposed method was implemented in plane wave imaging, and the performance was evaluated by simulated and phantom experiments. In simulation, the lateral spatial resolution and contrast obtained with the conventional CF were 0.23 mm and 47.0 dB, respectively, which were significantly better than 0.39 mm and 15.3 dB obtained by conventional delay-and-sum (DAS) beamforming. Using the proposed method, the lateral spatial resolution and contrast were further improved to 0.12 mm and 69.8 dB, respectively. Similar trends were found also in phantom experiments.

Low Complex Beam-Space Beamformer for Medical Ultrasound Imaging Based on Delay Multiply and Sum Method

2019 ◽  
Vol 9 (8) ◽  
pp. 1630-1638
Author(s):  
Ting Su ◽  
Shi Zhang ◽  
Dayu Li ◽  
Zhiwei Lv ◽  
Shengwei Dong
Keyword(s):  
Computational Complexity ◽  
Ultrasound Imaging ◽  
Contrast Ratio ◽  
Weight Vector ◽  
Minimum Variance ◽  
Medical Ultrasound Imaging ◽  
Adaptive Weight ◽  
Final Output ◽  
Simulation And Experiment ◽  
Low Complex

The beam-space minimum variance (BSMV) beamforming is an outstanding form of beam-space beamforming. However, its computational complexity is still high for real-time ultrasound imaging. To solve this problem, a beamforming named beam-space delay multiply and sum (BS-DMAS) beamforming was proposed in this paper. In the proposed method, similar decimation discrete cosine transform (DCT) matrix in BSMV was used to reduce the dimension of signal firstly. Then, the improved delay multiply and sum (DMAS) beamforming in parallel form was used to get the final output. Different from BSMV, instead of calculating the inverse of covariance matrix to get the adaptive weight vector, the proposed method just need to perform square root, sign and addition operation. By doing this, the computational complexity was reduced from PM + P3 + 3P2 + O(P) to PM + P2 + O(P) compared with BSMV. Finally, simulation and experiment was performed to evaluate the proposed method. Compared with DAS, the results indicate that BS-DMAS generates a 66% lower advantage at full width at half-maximum (FWHM), an 114% improvement at contrast noise ratio (CR) but slightly worse at contrast ratio (CNR). This demonstrates that the proposed method can improve the performance of imaging and reduce the computational complexity.

Subarray coherence based postfilter for eigenspace based minimum variance beamformer in ultrasound plane-wave imaging

Ultrasonics ◽  
2016 ◽  
Vol 65 ◽  
pp. 23-33 ◽  
Author(s):  
Jinxin Zhao ◽  
Yuanyuan Wang ◽  
Jinhua Yu ◽  
Wei Guo ◽  
Tianjie Li ◽  
...  
Keyword(s):  
Plane Wave ◽  
Minimum Variance ◽  
Wave Imaging
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