scholarly journals An Efficient Destructive Interference Based on Side Lobe Suppression Method in SONAR Beamforming

2021 ◽  
Vol 16 (1) ◽  
pp. 107-120
Author(s):  
S. Pillai ◽  
T. Santhanakrishnan ◽  
R. Rajesh
Keyword(s):  
Side Lobe ◽  
Beam Pattern ◽  
Primary Beam ◽  
Main Lobe ◽  
Destructive Interference ◽  
Rectangular Window ◽  
Window Functions ◽  
Suppression Method ◽  
Beamforming Technique ◽  
Side Lobe Suppression

A novel beamforming technique that resembles the principle of interference is proposed for sonar arrays to suppress the side lobes while the main lobe is kept intact. It uses two window functions. The first one is a rectangular function that produces a primary beam pattern. A secondary new window function is derived and its beam pattern is steered such that the null or trough of the main lobe of the new window coincides with the peak or crest of the first side lobe of the rectangular window and so on to other major side lobes. Pattern multiplication was used to get a final beam pattern. The approach is simulated and verified through a sonar array with 24 hydrophone sensors.

scholarly journals A Side-Lobe Suppression Method Based on Coherence Factor for Terahertz Array Imaging

IEEE Access ◽  
2018 ◽  
Vol 6 ◽  
pp. 5584-5588 ◽  
Author(s):  
Yanwen Jiang ◽  
Yuliang Qin ◽  
Hongqiang Wang ◽  
Bin Deng ◽  
Kang Liu ◽  
...  
Keyword(s):  
Side Lobe ◽  
Coherence Factor ◽  
Suppression Method ◽  
Array Imaging ◽  
Side Lobe Suppression

Excitation series design and pulse compression synthesis for high-resolution Lamb wave inspection

2018 ◽  
Vol 18 (5-6) ◽  
pp. 1464-1478
Author(s):  
Jiadong Hua ◽  
Liang Zeng ◽  
Jing Lin ◽  
Liping Huang
Keyword(s):  
Lamb Wave ◽  
Pulse Compression ◽  
Lamb Waves ◽  
Dispersion Compensation ◽  
Synthesis Method ◽  
Side Lobe ◽  
Main Lobe ◽  
Window Functions ◽  
Windowing Technique ◽  
Lobe Width

Lamb wave pulse compression is a promising technique for ultrasonic nondestructive evaluation and structural health monitoring, in which the excitation waveform is designed to exhibit attractive auto-correlation characteristics including short main-lobe width and small side-lobe amplitude. However, narrowing main-lobe will increase side-lobe amplitude, and vice versa. Conventional time windowing technique is a balance between main-lobe width and side-lobe amplitude. An improvement over time windowing is proposed using pulse compression synthesis method. In this method, a series of excitation waveforms are used to actuate Lamb waves, each response is processed by pulse compression, and all the compression signals are summed together. The excitation series are constructed as linear chirps weighted with different combinations of rectangular and Hanning window functions. The selection of the combination coefficients is optimized to ensure best signal summation. The effectiveness of the proposed method is demonstrated by an experiment, and the robustness to inaccuracy in dispersion compensation is also evaluated. Application of the proposed method for damage detection is demonstrated by a further experiment.

Multifrequency and Nonuniformly-Spaced Arrays: Effects on Grating Lobe Amplitude

1982 ◽  
Vol 4 (4) ◽  
pp. 351-354
Author(s):  
B. G. Bardsley ◽  
D. A. Christensen ◽  
T. A. Pryor
Keyword(s):  
Computer Simulation ◽  
Simulation Study ◽  
Ultrasonic Transducer ◽  
Side Lobe ◽  
Beam Pattern ◽  
Periodic Array ◽  
Main Lobe ◽  
Computer Simulation Study ◽  
Grating Lobe ◽  
Transducer Arrays

A computer simulation study on the effects of multifrequency and aperiodic ultrasonic transducer arrays has shown that both methods improve grating lobe response when compared to a periodic array of the same aperture and element spacing. The multifrequency array produces a better beam pattern than either the aperiodic or combination aperiodic/multifrequency array. Both the aperiodic and multifrequency arrays have a narrower main lobe and higher side lobe response than a periodic array with reduced element spacing and an equal number of elements.

Study of SAR Side-lobe Suppression Based on Compressed Sensing

2011 ◽  
Vol 32 (12) ◽  
pp. 3022-3026 ◽  
Author(s):  
Bo Kou ◽  
Hai Jiang ◽  
Lei Liu ◽  
Bing-chen Zhang
Keyword(s):  
Compressed Sensing ◽  
Side Lobe ◽  
Side Lobe Suppression

ULTRASONIC IMAGING SYSTEM USING A 2D ENVELOPE BEAMFORMING TECHNIQUE: IN-HOMOGENEITIES LOCATION

2004 ◽  
Vol 12 (04) ◽  
pp. 571-585
Author(s):  
L. MEDINA ◽  
E. MORENO
Keyword(s):  
Imaging System ◽  
Side Lobe ◽  
Ultrasonic Pulse ◽  
Image Resolution ◽  
Synthetic Aperture ◽  
Water Tank ◽  
Synthetic Aperture Focusing ◽  
Longitudinal Resolution ◽  
Synthetic Aperture Focusing Technique ◽  
Beamforming Technique

An algorithm has been developed to implement synthetic aperture focusing technique for B-scan. This is made at a several transmitter/receiver locations to form a map of ultrasonic reflectivity on the insonified region, considering the path travelled by the ultrasonic pulse from the transducer to the target and back again. To reconstruct the image, a time domain beam-former is applied to the envelope of the detected signals. This method minimizes the side-lobe amplitude and the restriction of λ/2 distance between two adjacent transducer positions can be neglected without loosing image resolution. The present work is focused on the location of the in-homogeneities, caused by the presence of a phantom immersed in a water tank. The results are presented when the distance between two adjacent transducer positions are varied from 0.5λ to 2.5λ showing that the longitudinal resolution is not affected but the lateral resolution becomes poorer when the distance is about 2λ. The error in the longitudinal location of in-homogeneities is within the minimum detectable distance of the system, while the lateral location error is increased when the distance between any two adjacent transducer positions is larger than 1.5λ.

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