Ambient noise imaging; enhanced spatial correlation algorithms and a way to combine independent images for improved stability and false-alarm rejection

2003 ◽  
Author(s):  
Choon Kiat Lim ◽  
J.R. Potter
Keyword(s):  
False Alarm ◽  
Spatial Correlation ◽  
Ambient Noise ◽  
Improved Stability

scholarly journals A spatial correlation model for the horizontal non-isotropic ocean ambient noise vector field

2017 ◽  
Vol 36 (2) ◽  
pp. 124-137 ◽  
Author(s):  
Jianbo Zhou ◽  
Shengchun Piao ◽  
Yiwang Huang ◽  
Shizhao Zhang ◽  
Ke Qu
Keyword(s):  
Vector Field ◽  
Spatial Correlation ◽  
Ambient Noise ◽  
Vibration Velocity ◽  
Ocean Bottom ◽  
Noise Field ◽  
Sonar System ◽  
Sensors Array ◽  
Ocean Environment ◽  
Von Mises

The ocean ambient noise is one of interference fields of underwater acoustic channel. The design and use of any sonar system are bound to be affected by ocean ambient noise, so to research the spatial correlation characteristics of noise field is of positive significance to improving the performance of sonar system. Only wind-generated noise is considered in most existing ambient noise models. In this case, the noise field is isotropic in horizontal direction. However, due to those influencing factors, like rainfall, ships and windstorm, etc. for a real ocean environment, noise field becomes anisotropic horizontally and the spatial structure of ambient field also changes correspondingly. This paper presents a spatial correlation of the acoustic vector field of anisotropic field by introducing Von Mises probability distribution to describe horizontal directivity. Closed-form expressions are derived which relate the cross-correlation among the sound pressure and three orthogonal components of vibration velocity, besides, the influence of the non-uniformity of noise field on the correlation characteristics of noise vector field was analysed. The model presented in this paper can provide theoretical guidance for the design and application of vector sensors array. Furthermore, the achievement could be applied to front extraction, Green’s function extraction, inversion for ocean bottom parameters, and so on.

scholarly journals Modeling of spatial correlation characteristics of broadband ocean ambient noise vector field

2022 ◽  
Vol 71 (2) ◽  
pp. 024301-024301
Author(s):  
Ren Chao ◽  
◽  
Huang Yi-Wang ◽  
Xia Zhi ◽  
◽  
...  
Keyword(s):  
Vector Field ◽  
Spatial Correlation ◽  
Ambient Noise

Hit and False-Alarm Rates of Selected ABR Indices in Differentiating Cochlear Disorders From Acoustic Tumors

1996 ◽  
Vol 5 (1) ◽  
pp. 90-96 ◽  
Author(s):  
Frank E. Musiek ◽  
Cynthia A. McCormick ◽  
Raymond M. Hurley
Keyword(s):  
False Alarm ◽  
Amplitude Ratio ◽  
High Specificity ◽  
Auditory Brainstem ◽  
Latency Difference ◽  
Cochlear Pathology ◽  
Brainstem Response ◽  
Absolute Latency ◽  
Two Indices ◽  
Low Sensitivity

We performed a retrospective study of 26 patients with acoustic tumors and 26 patients with otologically diagnosed cochlear pathology to determine the sensitivity (hit rate), specificity (false-alarm rate), and efficiency of six auditory brainstem response indices. In addition, a utility value was determined for each of these six indices. The I–V interwave interval, the interaural latency difference, and the absolute latency of wave V provided the highest hit rates, the best A’ values and good utility. The V/I amplitude ratio index provided high specificity but low sensitivity scores. In regard to sensitivity and specificity, using the combination of two indices provided little overall improvement over the best one-index measures.

The Fusion of False Alarm and False Hope

1985 ◽  
Vol 30 (3) ◽  
pp. 207-208
Author(s):  
Jeffrey Z. Rubin
Keyword(s):  
False Alarm
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