1
|
Shen CC, Huang CL. Improvement in Multi-Angle Plane Wave Image Quality Using Minimum Variance Beamforming with Adaptive Signal Coherence. Sensors (Basel) 2024; 24:262. [PMID: 38203125 PMCID: PMC10781243 DOI: 10.3390/s24010262] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/13/2023] [Revised: 12/26/2023] [Accepted: 12/29/2023] [Indexed: 01/12/2024]
Abstract
For ultrasound multi-angle plane wave (PW) imaging, the coherent PW compounding (CPWC) method provides limited image quality because of its conventional delay-and-sum beamforming. The delay-multiply-and-sum (DMAS) method is a coherence-based algorithm that improves image quality by introducing signal coherence among either receiving channels or PW transmit angles into the image output. The degree of signal coherence in DMAS is conventionally a global value for the entire image and thus the image resolution and contrast in the target region improves at the cost of speckle quality in the background region. In this study, the adaptive DMAS (ADMAS) is proposed such that the degree of signal coherence relies on the local characteristics of the image region to maintain the background speckle quality and the corresponding contrast-to-noise ratio (CNR). Subsequently, the ADMAS algorithm is further combined with minimum variance (MV) beamforming to increase the image resolution. The optimal MV estimation is determined to be in the direction of the PW transmit angle (Tx) for multi-angle PW imaging. Our results show that, using the PICMUS dataset, TxMV-ADMAS beamforming significantly improves the image quality compared with CPWC. When the p value is globally fixed to 2 as in conventional DMAS, though the main-lobe width and the image contrast in the experiments improve from 0.57 mm and 27.0 dB in CPWC, respectively, to 0.24 mm and 38.0 dB, the corresponding CNR decreases from 12.8 to 11.3 due to the degraded speckle quality. With the proposed ADMAS algorithm, however, the adaptive p value in DMAS beamforming helps to restore the CNR value to the same level of CPWC while the improvement in image resolution and contrast remains evident.
Collapse
Affiliation(s)
- Che-Chou Shen
- Department of Electrical Engineering, National Taiwan University of Science and Technology, Taipei 106335, Taiwan
| | | |
Collapse
|
2
|
Escárate P, Coronel M, Carvajal R, Agüero JC. An Optimal Integral Controller for Adaptive Optics Systems. Sensors (Basel) 2023; 23:9186. [PMID: 38005572 PMCID: PMC10675203 DOI: 10.3390/s23229186] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/04/2023] [Revised: 11/04/2023] [Accepted: 11/07/2023] [Indexed: 11/26/2023]
Abstract
Integral controllers are commonly employed in astronomical adaptive optics. This work presents a novel tuning procedure for integral controllers in adaptive optics systems which relies on information about the measured disturbances. This tuning procedure consists of two main steps. First, it models and identifies measured disturbances as continuous-time-damped oscillators using Whittles´s likelihood and the wavefront sensor output signal. Second, it determines the integral controller gain of the adaptive optics system by minimizing the output variance. The effectiveness of this proposed method is evaluated through theoretical examples and numerical simulations conducted using the Object-Oriented Matlab Adaptive Optics toolbox. The simulation results demonstrate that this approach accurately estimates the disturbance model and can reduce the output variance. Our proposal results in improved performance and better astronomical images even in challenging atmospheric conditions. These findings significantly contribute to adaptive optics system operations in astronomical observatories and establish our procedure as a promising tool for fine-tuning integral controllers in astronomical adaptive optics systems.
Collapse
Affiliation(s)
- Pedro Escárate
- School of Electrical Engineering, Pontificia Universidad Católica de Valparaíso (PUCV), Av. Brasil 2147, Valparaíso 2362804, Chile;
| | - María Coronel
- Department of Electricity, Universidad Tecnológica Metropolitana (UTEM), Av. Jose Pedro Alessandri 1242, Santiago 7800002, Chile;
| | - Rodrigo Carvajal
- School of Electrical Engineering, Pontificia Universidad Católica de Valparaíso (PUCV), Av. Brasil 2147, Valparaíso 2362804, Chile;
| | - Juan C. Agüero
- Electronics Engineering Department, Universidad Técnica Federico Santa María, Av. España 1680, Valparaíso 2390123, Chile;
| |
Collapse
|
3
|
Mukaddim RA, Varghese T. Spatiotemporal Coherence Weighting for In Vivo Cardiac Photoacoustic Image Beamformation. IEEE Trans Ultrason Ferroelectr Freq Control 2021; 68:586-598. [PMID: 32795968 PMCID: PMC8011040 DOI: 10.1109/tuffc.2020.3016900] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/20/2023]
Abstract
Photoacoustic (PA) image reconstruction generally utilizes delay-and-sum (DAS) beamforming of received acoustic waves from tissue irradiated with optical illumination. However, nonadaptive DAS reconstructed cardiac PA images exhibit temporally varying noise which causes reduced myocardial PA signal specificity, making image interpretation difficult. Adaptive beamforming algorithms such as minimum variance (MV) with coherence factor (CF) weighting have been previously reported to improve the DAS image quality. In this article, we report on an adaptive beamforming algorithm by extending CF weighting to the temporal domain for preclinical cardiac PA imaging (PAI). The proposed spatiotemporal coherence factor (STCF) considers multiple temporally adjacent image acquisition events during beamforming and cancels out signals with low spatial coherence and temporal coherence, resulting in higher background noise cancellation while preserving the main features of interest (myocardial wall) in the resultant PA images. STCF has been validated using the numerical simulations and in vivo ECG and respiratory-signal-gated cardiac PAI in healthy murine hearts. The numerical simulation results demonstrate that STCF weighting outperforms DAS and MV beamforming with and without CF weighting under different levels of inherent contrast, acoustic attenuation, optical scattering, and signal-to-noise (SNR) of channel data. Performance improvement is attributed to higher sidelobe reduction (at least 5 dB) and SNR improvement (at least 10 dB). Improved myocardial signal specificity and higher signal rejection in the left ventricular chamber and acoustic gel region are observed with STCF in cardiac PAI.
Collapse
|
4
|
Yan X, Qi Y, Wang Y, Wang Y. High Resolution, High Contrast Beamformer Using Minimum Variance and Plane Wave Nonlinear Compounding with Low Complexity. Sensors (Basel) 2021; 21:s21020394. [PMID: 33429947 PMCID: PMC7826701 DOI: 10.3390/s21020394] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 12/09/2020] [Revised: 12/31/2020] [Accepted: 01/05/2021] [Indexed: 12/05/2022]
Abstract
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.
Collapse
Affiliation(s)
- Xin Yan
- Department of Electronic Engineering, Fudan University, Shanghai 200433, China; (X.Y.); (Y.Q.); (Y.W.)
| | - Yanxing Qi
- Department of Electronic Engineering, Fudan University, Shanghai 200433, China; (X.Y.); (Y.Q.); (Y.W.)
| | - Yinmeng Wang
- Department of Electronic Engineering, Fudan University, Shanghai 200433, China; (X.Y.); (Y.Q.); (Y.W.)
| | - Yuanyuan Wang
- Department of Electronic Engineering, Fudan University, Shanghai 200433, China; (X.Y.); (Y.Q.); (Y.W.)
- Key Laboratory of Medical Imaging Computing and Computer Assisted Intervention of Shanghai, Shanghai 200032, China
- Correspondence:
| |
Collapse
|
5
|
Qi Y, Wang Y, Yu J, Guo Y. 2-D Minimum Variance Based Plane Wave Compounding with Generalized Coherence Factor in Ultrafast Ultrasound Imaging. Sensors (Basel) 2018; 18:s18124099. [PMID: 30477114 PMCID: PMC6308455 DOI: 10.3390/s18124099] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 10/28/2018] [Revised: 11/20/2018] [Accepted: 11/21/2018] [Indexed: 11/16/2022]
Abstract
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.
Collapse
Affiliation(s)
- Yanxing Qi
- Department of Electronic Engineering, Fudan University, Shanghai 200433, China.
| | - Yuanyuan Wang
- Department of Electronic Engineering, Fudan University, Shanghai 200433, China.
- Key Laboratory of Medical Imaging Computing and Computer Assisted Intervention (MICCAI) of Shanghai, Shanghai 200032, China.
| | - Jinhua Yu
- Department of Electronic Engineering, Fudan University, Shanghai 200433, China.
- Key Laboratory of Medical Imaging Computing and Computer Assisted Intervention (MICCAI) of Shanghai, Shanghai 200032, China.
| | - Yi Guo
- Department of Electronic Engineering, Fudan University, Shanghai 200433, China.
- Key Laboratory of Medical Imaging Computing and Computer Assisted Intervention (MICCAI) of Shanghai, Shanghai 200032, China.
| |
Collapse
|
6
|
Schecklman S, Zurk LM. Terahertz Imaging of Thin Film Layers with Matched Field Processing. Sensors (Basel) 2018; 18:E3547. [PMID: 30347738 DOI: 10.3390/s18103547] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 09/16/2018] [Revised: 10/07/2018] [Accepted: 10/09/2018] [Indexed: 11/16/2022]
Abstract
Terahertz (THz) time of flight (TOF) tomography systems offer a new measurement modality for non-destructive evaluation (NDE) of the subsurface layers of protective coatings and/or laminated composite materials for industrial, security and biomedical applications. However, for thin film samples, the time-of-flight within a layer is less than the duration of the THz pulse and consequently there is insufficient range resolution for NDE of the sample under test. In this paper, matched field processing (MFP) techniques are applied to thickness estimation in THz TOF tomography applications, and these methods are demonstrated by using measured THz spectra to estimate the the thicknesses of a thin air gap and its depth below the surface. MFP methods have been developed over several decades in the underwater acoustics community for model-based inversion of geo-acoustic parameters. It is expected that this research will provide an important link for THz researchers to access and apply the robust methods available in the MFP literature.
Collapse
|
7
|
Mozaffarzadeh M, Mahloojifar A, Orooji M, Kratkiewicz K, Adabi S, Nasiriavanaki M. Linear-array photoacoustic imaging using minimum variance-based delay multiply and sum adaptive beamforming algorithm. J Biomed Opt 2018; 23:1-15. [PMID: 29405047 DOI: 10.1117/1.jbo.23.2.026002] [Citation(s) in RCA: 47] [Impact Index Per Article: 7.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/18/2017] [Accepted: 01/08/2018] [Indexed: 05/20/2023]
Abstract
In photoacoustic imaging, delay-and-sum (DAS) beamformer is a common beamforming algorithm having a simple implementation. However, it results in a poor resolution and high sidelobes. To address these challenges, a new algorithm namely delay-multiply-and-sum (DMAS) was introduced having lower sidelobes compared to DAS. To improve the resolution of DMAS, a beamformer is introduced using minimum variance (MV) adaptive beamforming combined with DMAS, so-called minimum variance-based DMAS (MVB-DMAS). It is shown that expanding the DMAS equation results in multiple terms representing a DAS algebra. It is proposed to use the MV adaptive beamformer instead of the existing DAS. MVB-DMAS is evaluated numerically and experimentally. In particular, at the depth of 45 mm MVB-DMAS results in about 31, 18, and 8 dB sidelobes reduction compared to DAS, MV, and DMAS, respectively. The quantitative results of the simulations show that MVB-DMAS leads to improvement in full-width-half-maximum about 96%, 94%, and 45% and signal-to-noise ratio about 89%, 15%, and 35% compared to DAS, DMAS, MV, respectively. In particular, at the depth of 33 mm of the experimental images, MVB-DMAS results in about 20 dB sidelobes reduction in comparison with other beamformers.
Collapse
Affiliation(s)
- Moein Mozaffarzadeh
- Tarbiat Modares University, Department of Biomedical Engineering, Tehran, Iran
| | - Ali Mahloojifar
- Tarbiat Modares University, Department of Biomedical Engineering, Tehran, Iran
| | - Mahdi Orooji
- Tarbiat Modares University, Department of Biomedical Engineering, Tehran, Iran
| | - Karl Kratkiewicz
- Wayne State University, Department of Biomedical, Detroit, Michigan, United States
| | - Saba Adabi
- Wayne State University, Department of Biomedical, Detroit, Michigan, United States
| | | |
Collapse
|
8
|
Zhao J, Wang Y, Yu J, Guo W, Zhang S, Aliabadi S. Short-lag Spatial Coherence Ultrasound Imaging with Adaptive Synthetic Transmit Aperture Focusing. Ultrason Imaging 2017; 39:224-239. [PMID: 28068874 DOI: 10.1177/0161734616688328] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/06/2023]
Abstract
The short-lag spatial coherence (SLSC) imaging has been demonstrated to be advantageous over the traditional B-mode ultrasound imaging. With focused scanning beams, the SLSC imaging has an excellent performance in clutter reduction and lesion detection, especially in the low signal-to-noise ratio (SNR) scenarios. The synthetic aperture (SA) imaging is an appropriate mode for the SLSC imaging as the dynamic transmit focusing could keep a good focusing quality at any depth. However, the SLSC image may still suffer a bad resolution performance when a low lag value is used in the coherence summation to ensure the contrast enhancement. In this paper, an adaptive synthetic transmit (Tx) aperture focusing strategy is proposed for the SLSC imaging with the SA mode. Based on the achievements of adaptive beamforming, a minimum variance beamformer is applied in the Tx aperture to realize adaptive focusing. Spatial coherence is then measured in the receive aperture to form the SLSC image. Simulation and experimental studies were conducted to evaluate the proposed method. Experiments showed that the proposed method not only improved the poor resolution of the original SLSC image but also enhanced the speckle performance, which led to increased contrast-to-noise ratio and speckle SNR values.
Collapse
Affiliation(s)
- Jinxin Zhao
- 1 Department of Electronic Engineering, Fudan University, Shanghai, China
| | - Yuanyuan Wang
- 1 Department of Electronic Engineering, Fudan University, Shanghai, China
- 2 Key Laboratory of Medical Imaging Computing and Computer Assisted Intervention of Shanghai, Shanghai, China
| | - Jinhua Yu
- 1 Department of Electronic Engineering, Fudan University, Shanghai, China
- 2 Key Laboratory of Medical Imaging Computing and Computer Assisted Intervention of Shanghai, Shanghai, China
| | - Wei Guo
- 1 Department of Electronic Engineering, Fudan University, Shanghai, China
| | - Shun Zhang
- 1 Department of Electronic Engineering, Fudan University, Shanghai, China
| | - Saeid Aliabadi
- 1 Department of Electronic Engineering, Fudan University, Shanghai, China
| |
Collapse
|
9
|
Li J, Chen X, Wang Y, Li W, Yu D. Eigenspace-Based Generalized Sidelobe Canceler Beamforming Applied to Medical Ultrasound Imaging. Sensors (Basel) 2016; 16:E1192. [PMID: 27483272 DOI: 10.3390/s16081192] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 05/26/2016] [Revised: 07/22/2016] [Accepted: 07/26/2016] [Indexed: 11/16/2022]
Abstract
The use of a generalized sidelobe canceler (GSC) can significantly improve the lateral resolution of medical ultrasound systems, but the contrast improvement isn’t satisfactory. Thus a new Eigenspace-based generalized sidelobe canceler (EBGSC) approach is proposed for medical ultrasound imaging, which can improve both the lateral resolution and contrast of the system. The weight vector of the EBGSC is obtained by projecting the GSC weight vector onto a vector subspace constructed from the eigenstructure of the covariance matrix, and using the new weight vector instead of the GSC ones leads to reduced sidelobe level and improved contrast. Simulated and experimental data are used to evaluate the performance of the proposed method. The Field II software is applied to obtain the simulated echo data of scattering points and circular cysts. Imaging of scattering points show that EBGSC has the same full width at half maximum (FWHM) as GSC, while the lateral resolution improves by 35.3% and 52.7% compared with synthetic aperture (SA) and delay-and-sum (DS), respectively. Compared with GSC, SA and DS, EBGSC improves the peak sidelobe level (PSL) by 23.55, 33.11 and 50.38 dB, respectively. Also the cyst contrast increase by EBGSC was calculated as 16.77, 12.43 and 26.73 dB, when compared with GSC, SA and DS, respectively. Finally, an experiment is conducted on the basis of the complete echo data collected by a medical ultrasonic imaging system. Results show that the proposed method can produce better lateral resolution and contrast than non-adaptive beamformers.
Collapse
|
10
|
Aliabadi S, Yu J, Wang Y. Enhance contrast in PCA based beamformers using smoothing kernel. Biomed Mater Eng 2015; 26 Suppl 1:S1613-21. [PMID: 26405926 DOI: 10.3233/bme-151460] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/15/2022]
Abstract
The contrast and resolution have trade-off in medical ultrasound imaging. Most of adaptive beamformer can enhance the imaging resolution significantly but not improve the contrast at the same time. The principal component analysis (PCA) based beamformers such as the eigenspace-based minimum variance (ESBMV) beamformer provide a good imaging resolution. Neighbors of the focal point include the common noise, interface and signal components. Echo signal of the neighbor points can be used to suppress the noise and extract the signal component of the focal point. Based on this idea, in order to improve the quality of PCA based beamformers both in the imaging contrast and resolution, a novel beamforming method is proposed. This proposed beamformer utilizes a kernel to select neighbor points. The number of eigenvectors is estimated by using any PCA method. Then the number of selected eigenvectors for each focal point is compared with the number of selected eigenvectors of its neighbor points and is changed to a new value. The selected eigenvectors of the covariance matrix is used to construct the signal subspace. The estimated signal subspace is projected onto the minimum variance (MV) weight vector to calculate the desire weight vector. Results of experiments show that the proposed beamformer can improve the imaging contrast significantly while keeping the resolution quality similar to ESBMV beamformer.
Collapse
Affiliation(s)
- Saeid Aliabadi
- Department of Electronic Engineering, Fudan University, Shanghai 200433, China
| | - Jinhua Yu
- Department of Electronic Engineering, Fudan University, Shanghai 200433, China.,Key laboratory of Medical Imaging Computing and Computer Assisted Intervention of Shanghai, Shanghai 200433, China
| | - Yuanyuan Wang
- Department of Electronic Engineering, Fudan University, Shanghai 200433, China.,Key laboratory of Medical Imaging Computing and Computer Assisted Intervention of Shanghai, Shanghai 200433, China
| |
Collapse
|