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 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 In-vivo synthetic aperture and plane wave high frame rate cardiac imaging

2014 ◽  
Author(s):  
Matthias Bo Stuart ◽  
Jonas Jensen ◽  
Andreas Hjelm Brandt ◽  
Svetoslav Ivanov Nikolov ◽  
Michael Bachmann Nielsen ◽  
...  
Keyword(s):  
Plane Wave ◽  
Cardiac Imaging ◽  
Frame Rate ◽  
Synthetic Aperture ◽  
High Frame Rate

scholarly journals Topology of synaptic connectivity constrains neuronal stimulus representation, predicting two complementary coding strategies

2020 ◽  
Author(s):  
Michael W Reimann ◽  
Henri Riihimäki ◽  
Jason P Smith ◽  
Jānis Lazovskis ◽  
Christoph Pokorny ◽  
...  
Keyword(s):  
Dimensional Space ◽  
Brain Regions ◽  
Synaptic Connectivity ◽  
Dimensional Manifold ◽  
Coding Strategies ◽  
Stimulus Identity ◽  
Encoding Strategies ◽  
Lower Dimensional Space ◽  
Lower Dimensional

In motor-related brain regions, movement intention has been successfully decoded from in-vivo spike train by isolating a lower-dimension manifold that the high-dimensional spiking activity is constrained to. The mechanism enforcing this constraint remains unclear, although it has been hypothesized to be implemented by the connectivity of the sampled neurons. We test this idea and explore the interactions between local synaptic connectivity and its ability to encode information in a lower dimensional manifold through simulations of a detailed microcircuit model with realistic sources of noise. We confirm that even in isolation such a model can encode the identity of different stimuli in a lower-dimensional space. We then demonstrate that the reliability of the encoding depends on the connectivity between the sampled neurons by specifically sampling populations whose connectivity maximizes certain topological metrics. Finally, we developed an alternative method for determining stimulus identity from the activity of neurons by combining their spike trains with their recurrent connectivity. We found that this method performs better for sampled groups of neurons that perform worse under the classical approach, predicting the possibility of two separate encoding strategies in a single microcircuit.

scholarly journals Topology of synaptic connectivity constrains neuronal stimulus representation, predicting two complementary coding strategies

PLoS ONE ◽  
2022 ◽  
Vol 17 (1) ◽  
pp. e0261702
Author(s):  
Michael W. Reimann ◽  
Henri Riihimäki ◽  
Jason P. Smith ◽  
Jānis Lazovskis ◽  
Christoph Pokorny ◽  
...  
Keyword(s):  
Dimensional Space ◽  
Brain Regions ◽  
Synaptic Connectivity ◽  
Dimensional Manifold ◽  
Coding Strategies ◽  
Stimulus Identity ◽  
Encoding Strategies ◽  
Lower Dimensional Space ◽  
Lower Dimensional

In motor-related brain regions, movement intention has been successfully decoded from in-vivo spike train by isolating a lower-dimension manifold that the high-dimensional spiking activity is constrained to. The mechanism enforcing this constraint remains unclear, although it has been hypothesized to be implemented by the connectivity of the sampled neurons. We test this idea and explore the interactions between local synaptic connectivity and its ability to encode information in a lower dimensional manifold through simulations of a detailed microcircuit model with realistic sources of noise. We confirm that even in isolation such a model can encode the identity of different stimuli in a lower-dimensional space. We then demonstrate that the reliability of the encoding depends on the connectivity between the sampled neurons by specifically sampling populations whose connectivity maximizes certain topological metrics. Finally, we developed an alternative method for determining stimulus identity from the activity of neurons by combining their spike trains with their recurrent connectivity. We found that this method performs better for sampled groups of neurons that perform worse under the classical approach, predicting the possibility of two separate encoding strategies in a single microcircuit.

scholarly journals Efficient Transmit Delay Calculation in Ultrasound Coherent Plane-Wave Compound Imaging for Curved Array Transducers

2019 ◽  
Vol 9 (13) ◽  
pp. 2752
Author(s):  
Dooyoung Go ◽  
Jinbum Kang ◽  
Ilseob Song ◽  
Yangmo Yoo
Keyword(s):  
Computational Complexity ◽  
Plane Wave ◽  
Frame Rate ◽  
Steering Angle ◽  
In Vivo Experiments ◽  
Array Transducer ◽  
Multiple Plane ◽  
Curved Array Transducer ◽  
New Applications

The recently introduced plane-wave compounding method based on multiple plane-wave excitation has enabled several new applications due to its high frame rate (>1000 Hz). In this paper, a new efficient transmit delay calculation method in plane-wave compound imaging for a curved array transducer is presented. In the proposed method, the transmit delay is only calculated for a steering angle of 0° and is shifted along the element of the transducer to obtain other transmit delays for different steering angles. To evaluate the performance of the proposed method, the computational complexity was measured for various transmission conditions. For the number of elements and plane-wave excitations of 128 and 65, respectively, the number of operations was substantially decreased in the proposed method compared with the conventional method (256 vs. 8320). The benefits of the proposed method were demonstrated with phantom and in vivo experiments, where coherent plane-wave compounding with 65 excitations provided larger CR and CNR values compared to nine excitations (−22.5 dB and 2.7 vs. −11.3 dB and 1.9, respectively). These results indicate the proposed method can effectively reduce the computational complexity for plane-wave compound imaging in curved array transducers.

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