Background noise

About: Background noise is a research topic. Over the lifetime, 12671 publications have been published within this topic receiving 219820 citations. The topic is also known as: ambient noise.

Single channel speech enhancement based on masking properties of the human auditory system

Abstract: This paper addresses the problem of single channel speech enhancement at very low signal-to-noise ratios (SNRs) (<10 dB). The proposed approach is based on the introduction of an auditory model in a subtractive-type enhancement process. Single channel subtractive-type algorithms are characterized by a tradeoff between the amount of noise reduction, the speech distortion, and the level of musical residual noise, which can be modified by varying the subtraction parameters. Classical algorithms are usually limited to the use of fixed optimized parameters, which are difficult to choose for all speech and noise conditions. A new computationally efficient algorithm is developed based on masking properties of the human auditory system. It allows for an automatic adaptation in time and frequency of the parametric enhancement system, and finds the best tradeoff based on a criterion correlated with perception. This leads to a significant reduction of the unnatural structure of the residual noise. Objective and subjective evaluation of the proposed system is performed with several noise types form the Noisex-92 database, having different time-frequency distributions. The application of objective measures, the study of the speech spectrograms, as well as subjective listening tests, confirm that the enhanced speech is more pleasant to a human listener. Finally, the proposed enhancement algorithm is tested as a front-end processor for speech recognition in noise, resulting in improved results over classical subtractive-type algorithms.

All-pole modeling of degraded speech

Abstract: This paper considers the estimation of speech parameters in an all-pole model when the speech has been degraded by additive background noise. The procedure, based on maximum a posteriori (MAP) estimation techniques is first developed in the absence of noise and related to linear prediction analysis of speech. The modification in the presence of background noise is shown to be nonlinear. Two suboptimal procedures are suggested which have linear iterative implementations. A preliminary illustration and discussion based both on a synthetic example and real speech data are given.

The statistical performance of the MUSIC and the minimum-norm algorithms in resolving plane waves in noise

Abstract: This paper presents an asymptotic statistical analysis of the null-spectra of two eigen-assisted methods, MUSIC [1] and Minimum-Norm [2], for resolving independent closely spaced plane waves in noise. Particular attention is paid to the average deviation of the null-spectra from zero at the true angles of arrival for the plane waves. These deviations are expressed as functions of signal-to-noise ratios, number of array elements, angular separation of emitters, and the number of snapshots. In the case of MUSIC. an approximate expression is derived for the resolution threshold of two plane waves with equal power in noise. This result is validated by Monte Carlo simulations.

An Introduction to Underwater Acoustics¿Principles and Applications, (Second Edition)

Abstract: This textbook is a good overview of most of the aspects of underwater acoustics. It is comprehensive and covers some of the underwater acoustics fundamentals such as propagation, sound velocity profiles and their influence, background noise, scattering and target strength, absorption, transducers, arrays and array processing. In addition, it also covers applications of underwater acoustics—sonar, passive and active, sonar imaging, navigation aids, sub-bottom profiling, acoustic communications—including a discussion of the parameters that control the quality of the information in the application due to the effects of background noise, propagation and other underwater acoustics phenomena. In a chapter it treats underwater acoustics associated with marine mammals which is mostly descriptive, as one would expect, with data related to the hearing of mammals (audiograms), type and intensity of sound generated by mammals and the impact of natural and man-made sounds on the behavior of mammals. The material is presented in a way that allows someone who is not so familiar with underwater acoustics can use the book to gain a good background knowledge. Furthermore the book contains sufficient details so it can be used as a reference. While the textbook in general has all the right information, there are comments sprinkled throughout that may lead to a person to gain the wrong impression.