Forward acoustic scattering by moving objects: Theory and experiment

Lei, Bo; Yang, Kunde; Ma, Yuanliang; Wang, Lu

doi:10.1007/s11434-011-4880-6

Cited by 13 publications

(4 citation statements)

References 14 publications

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“…When only one path exists for the signal, matrix K decreases to one dimension, and the expression is similar as (30) in [24]. The test statistic can be further expressed as…”

Section: Glrt Derivationsmentioning

confidence: 99%

“…In the event of the intruder crossing the source-receiver line, an aberration in the received signals occurs due to the interference between the direct blast and scattered signal. When an object crosses at midpoint between the source and receiver, the acoustic field aberration is at the minimum [30]. Hence, to show the performance of the method in forward detection, a worse situation is considered in the simulation.…”

Section: Experimental Configurationmentioning

confidence: 99%

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GLRT-based Detection in Bistatic Sonar under Strong Direct Blast with Multipath Propagation

Lei¹,

Zhang²,

Yang³

2020

Preprint

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Direct blast is a strong interference in bistatic sonar and difficult to suppress due to multipath propagation for blasts and signals. A generalized likelihood ratio test (GLRT) based detection scheme in the frequency domain of the received signals is proposed in this study, and the unknown parameters are estimated using Maximum Likelihood Estimates and Weighted Fourier Transform and Relaxation in a multipath environment. The distributions of the test statistic of detectors for known and unknown noise power are given in theory, and the detection probability is determined. The performance of the detector decreases by 4 dB when the noise power is evaluated with maximum likelihood estimates. Simulations show the effectiveness of the detector under a forward scattering detection configuration with a low signal-to-direct blast ratio. The sensitivity of many factors is discussed, and robustness is achieved.

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“…When only one path exists for the signal, matrix K decreases to one dimension, and the expression is similar as (30) in [24]. The test statistic can be further expressed as…”

Section: Glrt Derivationsmentioning

confidence: 99%

Section: Experimental Configurationmentioning

confidence: 99%

GLRT-based Detection in Bistatic Sonar under Strong Direct Blast with Multipath Propagation

Lei¹,

Zhang²,

Yang³

2020

Preprint

Self Cite

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show abstract

“…In summary, despite the different applications of existing three mainstream video encryption schemes in different application fields owing to their respective advantages and disadvantages, tradeoff problems are widely present in the aspects of security and compression ratio, security and operability, as well as security and universality. This paper preferably solves the tradeoff between security and real-timeliness through the encryption of moving objects only [9].…”

Section: Research Status and Requirements On Video Encryptionmentioning

confidence: 99%

Research on Real-Time Video Encryption Algorithm Based on Moving Objects

Chen¹,

Chang-an²

2014

TOCSJ

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How to ensure the security and efficiency of real-time video transmission in the existing network environment is increasingly becoming an urgent problem to be solved. This paper presents a moving object-based video encryption algorithm, which can satisfactorily resolve the tradeoffs between security and efficiency of real-time video transmission. A real-time video encryption algorithm based on moving objects is proposed, which combines the extraction of moving objects with the entropy coding-based encryption algorithm, and encrypt only the extracted moving objects. Experimental results show that the algorithm has small computational overhead, and good encryption real-timeliness, which can achieve favourable tradeoffs between security and coding efficiency, and meet real-timeliness requirements.

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“…At the laboratory scale, Marandet et al [7] experimentally demonstrated the detection and localization of a wavelength-sized target in a shallow ultrasonic waveguide between two source-receiver arrays at 3 MHz. Lei et al [8], [9] further combined PCA with array processing to enhance the aberrations of the recorded direct arrival data on a short vertical receiver array (VRA), validated the performance of the proposed method on the basis of a lake experiment, and identified the relationship between sound field aberration and crossing distance in theory and experiment. The adaptive processing scheme and PCA-based concept are executed after acquiring several pulses.…”

Section: Introductionmentioning

confidence: 99%

Detection of Sound Field Aberrations Caused by Forward Scattering From Underwater Intruders Using Unsupervised Machine Learning

Lei¹,

Zhang²,

Yang³

2019

IEEE Access

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Forward scattered waves are produced by underwater intruders that cross a source-receiver line. Strong direct blasts lead to a difficult detection of sound field aberrations caused by forward scattered waves. An unsupervised detection scheme that processes repeatedly transmitted pulses on a receiver array is proposed. For detection under strong blasts, the scheme performs unsupervised learning on spectra of normalized envelopes on an array output, which has the advantage of robustness for weak field aberrations and real-time detection after effective training. An experiment was carried out on the lake; the results show that the method has yielded reliable results in comparison with approximately 1-dB aberrations on the received pulse strengths caused by forward scattering from an intruder. Furthermore, the relationship between strength aberrations caused by forward scattering and the location of the intruder through the baseline is discussed further, and the capabilities of the scheme are further discussed with noise-added experimental data. INDEX TERMS Forward scattering, littoral water, sound field aberration, unsupervised machine learning.

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Forward acoustic scattering by moving objects: Theory and experiment

Cited by 13 publications

References 14 publications

GLRT-based Detection in Bistatic Sonar under Strong Direct Blast with Multipath Propagation

GLRT-based Detection in Bistatic Sonar under Strong Direct Blast with Multipath Propagation

Research on Real-Time Video Encryption Algorithm Based on Moving Objects

Detection of Sound Field Aberrations Caused by Forward Scattering From Underwater Intruders Using Unsupervised Machine Learning

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