A Filtered Delay Weight Multiply and Sum (F-DwMAS) Beamforming for Ultrasound Imaging: Preliminary Results
01 Apr 2020-pp 312-315
TL;DR: The image quality improved by F-DwMAS compared to DAS and F-DMAS, a minimum-redundancy synthetic aperture technique for achieving high-quality imaging in low complex ultrasound systems.
Abstract: In this paper, the development of a modified beamforming method, named as, Filtered Delay Weight Multiply and Sum (F-DwMAS) beamforming is reported. The developed F-DwMAS method was investigated on a minimum-redundancy synthetic aperture technique, called as 2 Receive Synthetic Aperture Focussing Technique (2R-SAFT), which uses one element in the transmit and two consecutive elements in the receive, for achieving high-quality imaging in low complex ultrasound systems. Notably, in F-DwMAS, an additional aperture window function is designed and incorporated to the recently introduced F-DMAS method. The different methods of F-DwMAS, F-DMAS and Delay and Sum (DAS) were compared in terms of Lateral Resolution (LR), Axial Resolution (AR), Contrast Ratio (CR) and contrast-to-noise ratio (CNR) in a simulation study. Results show that the proposed F-DwMAS resulted in improvements of LR by 22.86 % and 25.19 %, AR by 5.18 % and 11.06 % and CR by 152 % and 112.8 % compared to those obtained using F-DMAS and DAS, respectively. However, CNR of F-DwMAS was 12.3 % less compared to DAS, but 103.09 % more than F-DMAS. Hence, it can be concluded that the image quality improved by F-DwMAS compared to DAS and F-DMAS.
Citations
More filters
07 Sep 2020
TL;DR: In this paper, a weighted nonlinear beamforming method called Filtered Delay Weighted Multiply and Sum (F-DwMAS) was proposed for Synthetic Transmit Aperture (STA) technique.
Abstract: In this paper, the development of weighted nonlinear beamformer, called as Filtered Delay Weighted Multiply and Sum (F-DwMAS) is reported. This method was investigated on Synthetic Transmit Aperture (STA) technique. The performance of the developed F-DwMAS method was compared with Delay and Sum (DAS) and recently introduced F-DMAS beamforming methods. Importantly, in the method proposed, an extra window stage is added after the delay stage in the F-DMAS method. The different methods of DAS, F-DMAS and F-DwMAS were compared in terms of the resulting image quality metrics, Lateral Resolution (LR), Axial Resolution (AR), Contrast Ratio (CR) and contrast-to-noise ratio (CNR), in experiments on tissue-mimicking phantoms. Experimental results show that, for STA technique, F-DwMAS resulted in improvements of AR by 46.91% and 30.19%, LR by 61.35% and 52.48%, CR by 84.68% and 27.51%, and CNR by 5.45% and 34.4% compared to those obtained using DAS and F-DMAS, respectively. Hence, it can be concluded that the image quality is improved by F-DwMAS compared to DAS and F-DMAS.
6 citations
Cites methods from "A Filtered Delay Weight Multiply an..."
...Most recently, a method named Filtered Delay weight Multiply and Sum (F-DwMAS) beamforming was proposed, which utilized an optimal weighting strategy for F-DMAS to improve the reconstructed image quality for the data acquired using 2-element Receive Synthetic Aperture Focusing Technique (2R-SAFT) scheme [27]....
[...]
11 Sep 2021
TL;DR: In this article, a modified nonlinear beamforming method, named as, Spatio-Temporal Delay Multiply and Sum (ST-DMAS), was investigated on a sparse-transmit Synthetic Transmit Aperture technique (sparse-STA) that used just 8 transmits to form the final ultrasound image.
Abstract: This work reports a modified nonlinear beamforming method, named as, Spatio-Temporal Delay Multiply and Sum (ST-DMAS). The developed ST-DMAS method was investigated on a sparse-transmit Synthetic Transmit Aperture technique (sparse-STA) that used just 8 transmits to form the final Ultrasound (US) image. This method allows for achieving high-quality imaging with improved frame rates. The different methods of Delay and Sum (DAS), Filtered Delay Multiply and Sum (F-DMAS) and ST-DMAS were compared in terms of Lateral Resolution (LR), Axial Resolution (AR), Contrast Ratio (CR) and contrast-to-noise ratio (CNR) in experimental studies. Experimental results show that ST-DMAS resulted in improvements of AR by 57 % and 49 %, LR by 61 % and 55 %, CR by 74 % and 43 %, and CNR by 45 % and 32 % in comparison to images reconstructed using DAS and F-DMAS, respectively. Hence, a conclusion can be drawn that both the image quality and frame rate of an US system can be improved by ST-DMAS compared to DAS and F-DMAS.
5 citations
11 Sep 2021
TL;DR: In this paper, a new non-linear beamforming method, namely, Filtered Delay Adaptively Weighted Multiply and Sum (F-DawMAS) beamforming is reported for conventional focusing technique (CFT).
Abstract: This work reports a new non-linear beamforming method, namely, Filtered Delay adaptively-weighted Multiply and Sum (F-DawMAS) beamforming is reported for Conventional Focusing Technique (CFT). The proposed F-DawMAS beamformer was compared against the routinely used Delay and Sum (DAS) and Filtered Delay Multiply and Sum (F-DMAS) beamforming methods. Notably, in the proposed method optimal adaptive weights are computed for each pixel to compensate for the effects due to spatial variations in beam pattern in CFT technique. The proposed F-DawMAS is compared with F-DMAS, and DAS in terms, Lateral Resolution (LR), Axial Resolution (AR), Contrast Ratio (CR) and contrast-to-noise ratio (CNR), estimated from experiments performed on tissue-mimicking phantom. Experimental results show that F-DawMAS resulted in improvements of AR by 58 % and 49 %, LR by 60 % and 53 %, CR by 73 % and 43 %, and CNR by 40 % and 28 % compared to DAS and F-DMAS, respectively. Thus, a conclusion can be drawn that the newly proposed F-DawMAS outperforms F-DMAS and DAS.
4 citations
TL;DR: In this paper, a novel non-linear beamforming method, namely, filtered delay optimally-weighted multiply and sum (F-DowMAS) beamforming is reported for conventional focused beamforming (CFB) technique.
Abstract: A novel non-linear beamforming method, namely, filtered delay optimally-weighted multiply and sum (F-DowMAS) beamforming is reported for conventional focused beamforming (CFB) technique. The performance of F-DowMAS was compared against delay and sum (DAS), filtered delay multiply and sum (F-DMAS), filtered delay weight multiply and sum (F-DwMAS) and filter delay Euclidian weighted multiply and sum (F-DewMAS) methods. Notably, in the proposed method the optimal adaptive weights are computed for each imaging point to compensate for the effects due to spatial variations in beam pattern in CFB technique. F-DowMAS, F-DMAS, and DAS were compared in terms of the resulting image quality metrics, Lateral resolution (LR), axial resolution (AR), contrast ratio (CR) and contrast-to-noise ratio (CNR), estimated from experiments on a commercially available tissue-mimicking phantom. The results demonstrate that F-DowMAS improved the AR by 57.04% and 46.95%, LR by 58.21% and 53.40%, CR by 67.35% and 39.25%, and CNR by 44.04% and 30.57% compared to those obtained using DAS and F-DMAS, respectively. Thus, it can be concluded that the newly proposed F-DowMAS outperforms DAS and F-DMAS. As an aside, we also show that the optimal weighting strategy can be extended to benefit DAS.
4 citations
10 Oct 2022
TL;DR: In this article , a hybrid two-element scanner (HyTES) was proposed for high-frequency ultrasound imaging, which utilizes a combination of a focused and an unfocused highfrequency transducer elements to improve the quality of reconstructed image.
Abstract: This paper presents a novel hybrid two-element scanner (HyTES) for high-frequency ultrasound imaging. The proposed scanner utilizes a combination of a focused and an unfocused high-frequency transducer elements to improve the quality of reconstructed image. An experimental prototype of the proposed scanner is made to serve as proof-of-concept. The scan data obtained from the proposed scheme is beamformed using the recently proposed non-linear beamformer of F-DewMAS, and the results are compared with state-of-the-art monostatic Delay-And-Sum (DAS) and recently proposed Virtual -source-in-front of the transducer with DAS (VS-DAS) beamforming that uses data from only the focused element. As a minor innovation, Virtual Source beamforming is adapted to Delay-Multiply-And-Sum to develop VS-DMAS, which is utilized to reconstruct two element data and the results are compared with other methods. The proposed scanning technology with F-DewMAS beamforming is able improve the image quality by more than 52 % and 63 % in terms of resolution and by more than 44 % and 57 % in terms of CNR and GCNR compared to the recent VS-DAS and monostatic DAS, respectively. Further, the newly proposed VS-DMAS was able to improve resolution and contrast compared to existing methods. However, the performance in terms of the image quality metrics were not as much as obtained with the proposed HyTES. The proposed technology has the potential to improve the image quality without the need for an array, manufacturing of which is a challenge at High-frequencies.
1 citations
References
More filters
TL;DR: Multi-element synthetic aperture imaging methods suitable for applications with severe cost and size limitations are explored in this article, where each method uses different spatial frequencies and acquisition strategies for imaging, and therefore different sets of active transmit/receive element combinations.
Abstract: Multi-element synthetic aperture imaging methods suitable for applications with severe cost and size limitations are explored. Array apertures are synthesized using an active multi-element receive subaperture and a multi-element transmit subaperture defocused to emulate a single-element spatial response with high acoustic power. Echo signals are recorded independently by individual elements of the receive subaperture. Each method uses different spatial frequencies and acquisition strategies for imaging, and therefore different sets of active transmit/receive element combinations. Following acquisition, image points are reconstructed using the complete data set with full dynamic focus on both transmit and receive. Various factors affecting image quality have been evaluated and compared to conventional imagers through measurements with a 3.5 MHz, 128-element transducer array on different gel phantoms. Multielement synthetic aperture methods achieve higher electronic signal to noise ratio and better contrast resolution than conventional synthetic aperture techniques, approaching conventional phased array performance. >
595 citations
"A Filtered Delay Weight Multiply an..." refers background in this paper
...Several efforts have been made to reduce the cost and complexity of the US system to make it suitable for point of care application in rural and resource-poor settings [1-5]....
[...]
TL;DR: Results show that the DMAS beamformer outperforms DAS in both simulated and experimental trials and that the main improvement brought about by this new method is a significantly higher contrast resolution, which turns out into an increased dynamic range and better quality of B-mode images.
Abstract: Most of ultrasound medical imaging systems currently on the market implement standard Delay and Sum (DAS) beamforming to form B-mode images. However, image resolution and contrast achievable with DAS are limited by the aperture size and by the operating frequency. For this reason, different beamformers have been presented in the literature that are mainly based on adaptive algorithms, which allow achieving higher performance at the cost of an increased computational complexity. In this paper, we propose the use of an alternative nonlinear beamforming algorithm for medical ultrasound imaging, which is called Delay Multiply and Sum (DMAS) and that was originally conceived for a RADAR microwave system for breast cancer detection. We modify the DMAS beamformer and test its performance on both simulated and experimentally collected linear-scan data, by comparing the Point Spread Functions, beampatterns, synthetic phantom and in vivo carotid artery images obtained with standard DAS and with the proposed algorithm. Results show that the DMAS beamformer outperforms DAS in both simulated and experimental trials and that the main improvement brought about by this new method is a significantly higher contrast resolution (i.e., narrower main lobe and lower side lobes), which turns out into an increased dynamic range and better quality of B-mode images.
376 citations
"A Filtered Delay Weight Multiply an..." refers background or methods in this paper
...In standard DMAS the acquired raw RF data is delayed to make them in phase and combinatorially coupled and multiplied before being summed [6]....
[...]
...A new beamforming method called as Delay Multiply and Sum beamforming (DMAS) proposed in the microwave literature was recently adapted to the US imaging with some modifications and was named as Filtered Delay Multiply and Sum beamforming (F-DMAS) [6]....
[...]
...Also, the developed method was used to reconstruct the data acquired using 2R-SAFT, instead of conventional focused beamforming or plane wave imaging or Synthetic Transmit Aperture (STA) where the use of FDMAS has been reported [6,9,10]....
[...]
...Due to the multiplication of the signals with similar frequency content a DC and a second harmonic component appears in the spectrum of DMAS, therefore a further step of bandpass filtering was introduced to filter the DC and higher frequency components and is named as filtered DMAS (F-DMAS)[6]....
[...]
TL;DR: A new coherent array imaging method - phased subarray (PSA) imaging - is proposed that performs partial transmit and receive beam-forming using a subset of adjacent elements at each firing step, reducing the complexity of the front-end hardware while achieving image quality approaching that of FPA imaging.
Abstract: The front-end hardware complexity of a coherent array imaging system scales with the number of active array elements that are simultaneously used for transmission or reception of signals. Different imaging methods use different numbers of active channels and data collection strategies. Conventional full phased array (FPA) imaging produces the best image quality using all elements for both transmission and reception, and it has high front-end hardware complexity. In contrast, classical synthetic aperture (CSA) imaging only transmits on and receives from a single element at a time, minimizing the hardware complexity but achieving poor image quality. We propose a new coherent array imaging method - phased subarray (PSA) imaging - that performs partial transmit and receive beam-forming using a subset of adjacent elements at each firing step. This method reduces the number of active channels to the number of subarray elements; these channels are multiplexed across the full array and a reduced number of beams are acquired from each subarray. The low-resolution subarray images are laterally upsampled, interpolated, weighted, and coherently summed to form the final high-resolution PSA image. The PSA imaging reduces the complexity of the front-end hardware while achieving image quality approaching that of FPA imaging
75 citations
"A Filtered Delay Weight Multiply an..." refers background in this paper
...Several efforts have been made to reduce the cost and complexity of the US system to make it suitable for point of care application in rural and resource-poor settings [1-5]....
[...]
TL;DR: The introduced method, namely double-stage DMAS (DS-DMAS), results in an approximately 25% lower level of side lobes compared with DMAS, and leads to 23%, 22% and 43% improvement in signal-to-noise ratio, full width at half-maximum and contrast ratio, respectively, compared with the DMAS beamformer.
Abstract: In ultrasound (US) imaging, delay and sum (DAS) is the most common beamformer, but it leads to low-quality images. Delay multiply and sum (DMAS) was introduced to address this problem. However, the reconstructed images using DMAS still suffer from the level of side lobes and low noise suppression. Here, a novel beamforming algorithm is introduced based on expansion of the DMAS formula. We found that there is a DAS algebra inside the expansion, and we proposed use of the DMAS instead of the DAS algebra. The introduced method, namely double-stage DMAS (DS-DMAS), is evaluated numerically and experimentally. The quantitative results indicate that DS-DMAS results in an approximately 25% lower level of side lobes compared with DMAS. Moreover, the introduced method leads to 23%, 22% and 43% improvement in signal-to-noise ratio, full width at half-maximum and contrast ratio, respectively, compared with the DMAS beamformer.
70 citations
"A Filtered Delay Weight Multiply an..." refers background in this paper
...researchers proposed a double stage DMAS and showed that it resulted in the improvement of Full-Width-HalfMaximum (FWHM) and contrast [7]....
[...]
TL;DR: Baseband DMAS (BB-DMAS) beamforming provides flexible manipulation of image quality by introducing baseband spatial coherence in the ultrasonic imaging by reducing the need for oversampling.
41 citations
Additional excerpts
...Another research group came up with Baseband-DMAS (BB-DMAS) where p root of delayed RF data is computed and after the summation the power is restored by p power and showed an improvement in the contrast of the reconstructed US image [8]....
[...]