scholarly journals Ultrasound Imaging Algorithm: Half-Matrix Focusing Method Based on Reciprocity

2021 ◽  
Vol 2021 ◽  
pp. 1-11
Author(s):  
Xufei Guo ◽  
Yan Han ◽  
Pengfei Nie
Keyword(s):  
Phased Array ◽  
Linear Array ◽  
Signal To Noise Ratio ◽  
Industrial Applications ◽  
Signal To Noise ◽  
Full Matrix ◽  
Calculation Process ◽  
Ultrasonic Phased Array ◽  
Data Capturing ◽  
Noise Ratio

The ultrasonic phased array total focusing method (TFM) has the advantages of high imaging signal-to-noise ratio (SNR) and high defect resolution, but the problem of large amount data capturing and processing limits its practical industrial applications. To reduce the imaging calculation demand of the total focusing method, a half-matrix focusing method (HFM) is proposed based on the acoustic reciprocity. The method simplifies the calculation process of full-matrix data capturing (FMC) and total focus imaging. The experimental results show that the signal obtained by the linear array transceiver sensor is highly consistent, and the imaging resolution and signal-to-noise ratio of the half-matrix focusing method are slightly lower than those of full-matrix focusing method and higher than those of the B-scan imaging. However, compared with TFM, data acquisition and computational efficiency using the HFM have been improved significantly.

A hybrid neural network goal attain optimization for failed sensor(s) radiation pattern in linear array

2019 ◽  
Vol 4 (4) ◽  
pp. 101-109
Author(s):  
Navaamsini Boopalan ◽  
Agileswari K. Ramasamy ◽  
Farrukh Hafiz Nagi
Keyword(s):  
Neural Network ◽  
Radiation Pattern ◽  
Array Signal Processing ◽  
Linear Array ◽  
Signal To Noise Ratio ◽  
Beam Pattern ◽  
Sensor Failure ◽  
Signal To Noise ◽  
Hybrid Neural Network ◽  
Noise Ratio

Array sensors are widely used in various fields such as radar, wireless communications, autonomous vehicle applications, medical imaging, and astronomical observations fault diagnosis. Array signal processing is accomplished with a beam pattern which is produced by the signal's amplitude and phase at each element of array. The beam pattern can get rigorously distorted in case of failure of array element and effect its Signal to Noise Ratio (SNR) badly. This paper proposes on a Hybrid Neural Network layer weight Goal Attain Optimization (HNNGAO) method to generate a recovery beam pattern which closely resembles the original beam pattern with remaining elements in the array. The proposed HNNGAO method is compared with classic synthesize beam pattern goal attain method and failed beam pattern generated in MATLAB environment. The results obtained proves that the proposed HNNGAO method gives better SNR ratio with remaining working element in linear array compared to classic goal attain method alone. Keywords: Backpropagation; Feed-forward neural network; Goal attain; Neural networks; Radiation pattern; Sensor arrays; Sensor failure; Signal-to-Noise Ratio (SNR)

scholarly journals Network and Field Analysis of Koch Snowflake Fractal Geometry Radiofrequency Coils for Sodium MRI

2021 ◽  
Vol 9 ◽  
Author(s):  
Cameron E. Nowikow ◽  
Paul Polak ◽  
Norman B. Konyer ◽  
Natalia K. Nikolova ◽  
Michael D. Noseworthy
Keyword(s):  
Phased Array ◽  
Signal To Noise Ratio ◽  
Surface Coil ◽  
Homogeneous Field ◽  
Signal To Noise ◽  
Sodium Mri ◽  
Circular Coil ◽  
Radiofrequency Coils ◽  
Koch Snowflake ◽  
Noise Ratio

Sodium is one of the most abundant physiological cations and is a key element in many cellular processes. It has been shown that several pathologies, including degenerative brain disorders, cancers, and brain traumas, express sodium deviations from normal. Therefore, sodium magnetic resonance imaging (MRI) can prove to be valuable for physicians. However, sodium MRI has its limitations, the most significant being a signal-to-noise ratio (SNR) thousands of times lower than a typical proton MRI. Radiofrequency coils are the components of the MRI system directly responsible for signal generation and acquisition. This paper explores the intrinsic properties of a Koch snowflake fractal radiofrequency surface coil compared to that of a standard circular surface coil to investigate a fractal geometry’s role in increasing SNR of sodium MRI scans. By first analyzing the network parameters of the two coils, it was found that the fractal coil had a better impedance match than the circular coil when loaded by various anatomical regions. Although this maximizes signal transfer between the coil and the system, this is at the expense of a lower Q, indicating greater signal loss between the tissue and coil. A second version of each coil was constructed to test the mutual inductance between the coils of the same geometry to see how they would behave as a phased array. It was found that the fractal coils were less sensitive to each other than the two circular coils, which would be beneficial when constructing and using phased array systems. The performance of each coil was then assessed for B1+ field homogeneity and signal. A sodium phantom was imaged using a B1+ mapping sequence, and a 3D radial acquisition was performed to determine SNR and image quality. The results indicated that the circular coil had a more homogeneous field and higher SNR. Overall while the circular coil proved to generate a higher signal-to-noise ratio than the fractal, the Koch coil showed higher versatility when in a multichannel network which could prove to be a benefit when designing, constructing, and using a phased array coil.

Artifacts by Misalignment of Cardiac Magnetic Resonance Phased-array Coil Elements: From Simulation to In vivo Test

2019 ◽  
Vol 15 (3) ◽  
pp. 301-307
Author(s):  
Daniele De Marchi ◽  
Alessandra Flori ◽  
Nicola Martini ◽  
Giulio Giovannetti
Keyword(s):  
Cardiac Magnetic Resonance ◽  
Magnetic Resonance ◽  
Phased Array ◽  
Signal To Noise Ratio ◽  
Whole Body ◽  
Signal To Noise ◽  
Phased Array Coil ◽  
Noise Ratio ◽  
Array Coil

Background: Cardiac magnetic resonance evaluations generally require a radiofrequency coil setup comprising a transmit whole-body coil and a receive coil. In particular, radiofrequency phased-array coils are employed to pick up the signals emitted by the nuclei with high signal-tonoise ratio and a large region of sensitivity. Methods: Literature discussed different technical issues on how to minimize interactions between array elements and how to combine data from such elements to yield optimum Signal-to-Noise Ratio images. However, image quality strongly depends upon the correct coil position over the heart and of one array coil portion with respect to the other. Results: In particular, simple errors in coil positioning could cause artifacts carrying to an inaccurate interpretation of cardiac magnetic resonance images. Conclusion: This paper describes the effect of array elements misalignment, starting from coil simulation to cardiac magnetic resonance acquisitions with a 1.5 T scanner. </P><P> Phased-array coil simulation was performed using the magnetostatic approach; moreover, phantom and in vivo experiments with a commercial 8-elements cardiac phased-array receiver coil permitted to estimate signal-to-noise ratio and B1 mapping for aligned and shifted coil.

scholarly journals Investigation on the Inspection Technology of GH3535 Alloy Butt Weld With Linear Array Probe

2021 ◽  
Author(s):  
Xiaodan Yuan A ◽  
Yuan Zhang B ◽  
Zhijun Li ◽  
Kun Yu C ◽  
Jinlong Wang D
Keyword(s):  
Linear Array ◽  
Signal To Noise Ratio ◽  
Ultrasonic Inspection ◽  
Acoustic Beam ◽  
Signal To Noise ◽  
Butt Weld ◽  
Array Probe ◽  
Columnar Grains ◽  
Noise Ratio ◽  
Linear Array Probe

Abstract The critical problem to accurately characterizing defects in GH3535 alloy weld is the deflection of the acoustic beam and scattering due to the coarse columnar grains. Signal-to-noise ratio is an important index to indicate whether the grain scattering is severein the ultrasonic inspection. In this paper, the phased array ultrasonic testing of GH3535 alloy butt weld was studied using sector scan mode with linear array probe. The soundfield characteristics of the linear array probe with different focusing parameters were analyzed, and the signal-to-noise ratio in the detection was calculated. The results show that: the acoustic beam of the linear array probe can cover the weld,based on the removal of weld reinforcement. The signal-to-noise ratio of transverse hole with φ3mm located at the weld-fusion lineis more than 15dB, when the front end ofthe probe is located directly above the transverse hole of weld-fusion line.

Novel splittable N-Tx/2N-Rx transceiver phased array to optimize both signal-to-noise ratio and transmit efficiency at 9.4T

2015 ◽  
Vol 76 (5) ◽  
pp. 1621-1628 ◽  
Author(s):  
Nikolai I. Avdievich ◽  
Ioannis A. Giapitzakis ◽  
Anke Henning
Keyword(s):  
Phased Array ◽  
Signal To Noise Ratio ◽  
Signal To Noise ◽  
Noise Ratio

Computationally rapid method of estimating signal-to-noise ratio for phased array image reconstructions

2011 ◽  
Vol 66 (4) ◽  
pp. 1192-1197 ◽  
Author(s):  
Curtis N. Wiens ◽  
Shawn J. Kisch ◽  
Jacob D. Willig-Onwuachi ◽  
Charles A. McKenzie
Keyword(s):  
Rapid Method ◽  
Phased Array ◽  
Signal To Noise Ratio ◽  
Signal To Noise ◽  
Image Reconstructions ◽  
Noise Ratio
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