An orbital angular momentum acoustic metasurface for underwater defect detection

2021 ◽  
Author(s):  
Qiujun Ma ◽  
Chunyao Lu ◽  
Igor V. Minin ◽  
Oleg V. Minin ◽  
Kangyu Wang ◽  
...  
Keyword(s):  
Angular Momentum ◽  
Orbital Angular Momentum ◽  
Defect Detection ◽  
Phased Array ◽  
Simple Structure ◽  
Detection Method ◽  
Signal To Noise Ratio ◽  
High Signal ◽  
Reference Library ◽  
Reference Pattern

Abstract Fourier diffraction theorem can rapidly predict scattering characteristics of scatterers. This paper theoretically proposes Orbital Angular Momentum (OAM) to simplify the reference library in the underwater Fourier diffraction theorem. An acoustic metasurface is designed to replace the traditional phased array, meanwhile the underwater defect detection combining OAM and Fourier diffraction theorem is verified in the simulation. This acoustic metasurface has a high signal-to-noise ratio (SNR) when used for underwater defect detection. Compared with the traditional underwater defect detection method, the underwater defect detection method proposed in this paper has the advantages of simple structure and no reference pattern library.

Interferometric Detection Method for Orbital Angular Momentum of Vortex Beams

2019 ◽  
Vol 56 (14) ◽  
pp. 140502
Author(s):  
裴春莹 Chunying Pei ◽  
茅志翔 Zhixiang Mao ◽  
徐素鹏 Supeng Xu ◽  
夏勇 Yong Xia ◽  
尹亚玲 Yaling Yin
Keyword(s):  
Angular Momentum ◽  
Orbital Angular Momentum ◽  
Detection Method ◽  
Vortex Beams ◽  
Interferometric Detection

scholarly journals Blind audio source separation based on a new system model and the Savitzky-Golay filter

2021 ◽  
Vol 72 (3) ◽  
pp. 208-212
Author(s):  
Pengfei Xu ◽  
Yinjie Jia ◽  
Mingxin Jiang
Keyword(s):  
Simple Structure ◽  
Signal To Noise Ratio ◽  
Source Separation ◽  
System Model ◽  
High Signal ◽  
Audio Signals ◽  
Signal To Noise ◽  
Proposed Model ◽  
Source Signals ◽  
New System

Abstract Blind source separation (BSS) is a research hotspot in the field of signal processing. This scheme is widely applied to separate a group of source signals from a given set of observations or mixed signals. In the present study, the Savitzky-Golay filter is applied to smooth the mixed signals, adopt a simplified cost function based on the signal to noise ratio (SNR) and obtain the demixing matrix accordingly. To this end, the generalized eigenvalue problem is solved without conventional iterative methods. It is founded that the proposed algorithm has a simple structure and can be easily implemented in diverse problems. The obtained results demonstrate the good performance of the proposed model for separating audio signals in cases with high signal to noise ratios.

scholarly journals Coherent Fourier scatterometry using orbital angular momentum beams for defect detection

2020 ◽  
Author(s):  
Chen-Ting Liao ◽  
Bin Wang ◽  
Michael Tanksalvala ◽  
Zhe Zhang ◽  
Yuka Esashi ◽  
...  
Keyword(s):  
Angular Momentum ◽  
Orbital Angular Momentum ◽  
Defect Detection

scholarly journals Optical vortex beams with controllable orbital angular momentum using an optical phased array

OSA Continuum ◽  
2020 ◽  
Vol 3 (12) ◽  
pp. 3399
Author(s):  
David R. Gozzard ◽  
James T. Spollard ◽  
Paul G. Sibley ◽  
Lyle E. Roberts ◽  
Daniel A. Shaddock
Keyword(s):  
Angular Momentum ◽  
Orbital Angular Momentum ◽  
Phased Array ◽  
Optical Vortex ◽  
Vortex Beams ◽  
Optical Phased Array

scholarly journals Defining Effective Gain for Evaluation of Orbital Angular Momentum Links

2021 ◽  
Vol 6 (2) ◽  
pp. 117-127
Author(s):  
Elaheh Shamoushaki ◽  
Hadi Aliakbarian
Keyword(s):  
Angular Momentum ◽  
Radio Frequency ◽  
Radiation Pattern ◽  
Orbital Angular Momentum ◽  
Phased Array ◽  
Communication Link ◽  
Phased Array Antennas ◽  
Array Antennas ◽  
Link Budget ◽  
First Time

In this paper, a communication link based on circular phased array antennas generating orbital angular momentum (OAM) beams at radio frequency is investigated. The presence of a null in the radiation pattern of OAM antennas is the main drawback of them. This problem makes it difficult to establish a telecommunication link using OAM systems and calculate the link budget for such a system. To solve this problem, we have defined two new gain parameters by using Friis Transmission Equation. The new formulas can help to calculate the effective gain of OAM antennas. Also, we have defined the effective OAM gain in detail for the first time in order to evaluate the performance of the OAM links. By using the proposed formulas, a capable and secure link based on the orthogonality of OAM beams can be designed.

High Signal-to-Noise Ratio Ultrasonic Point Detection Method using a Fused Quartz Rod as a Pulse Compression Filter and a Sensor

1997 ◽  
Vol 36 (Part 1, No. 5B) ◽  
pp. 3157-3159 ◽  
Author(s):  
Masasumi Yoshizawa ◽  
Norio Tagawa ◽  
Eiki Watanabe ◽  
Tadashi Moriya ◽  
Shin-ichi Yagi
Keyword(s):  
Pulse Compression ◽  
Detection Method ◽  
Signal To Noise Ratio ◽  
High Signal ◽  
Signal To Noise ◽  
Fused Quartz ◽  
Noise Ratio ◽  
Point Detection

Ultrasonic Phased Array Industrial Imaging Research with Compressed Sensing

2013 ◽  
Vol 347-350 ◽  
pp. 317-321 ◽  
Author(s):  
Xian Yue Ouyang ◽  
Guang Zhi Dai ◽  
Ren Fa Li ◽  
Qing Guang Zeng
Keyword(s):  
Compressed Sensing ◽  
Defect Detection ◽  
Phased Array ◽  
Signal To Noise Ratio ◽  
Sparse Sampling ◽  
Spectrum Estimation ◽  
Experiment System ◽  
Recovery Algorithm ◽  
Ultrasonic Phased Array ◽  
Focus Detection

this study presents an eight array ultrasonic signal phased array sparse sampling experiment system based ultrasonic phased array technology and Compressed Sensing (CS). Proposed system considers recovery ultrasonic beam signal received eight phased array elements with sparse samples captured using sub-Nyquist model in CS recovery algorithm. We have the block defect detection test in the system. The test result approximated the actual block defect position. Based on block defect detection test, We compared sparse sampling value using spectrum estimation to Compressed Sensing recovery algorithm imaging, and no focus and focus detection effect, proved the phased array experiment system based on Compressed Sensing .it can greatly improve the detection signal to noise ratio (SNR) and sensitivity. So we verify the phased array focus can improve the detection ability.

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