An accurate and low-cost level measurement method based on acoustic resonance is presented. The method is useful in the cases that measurements are noisy which might be due to environment noise or due to low-cost instruments used in the measurement process. An iterative nonlinear filtering algorithm, called the “Unscented Kalman filter” (UKF) has been employed to obtain a good estimate of the n...

Active Noise Reduction (ANR) technique has been available for hearing protectors and communication headsets for years. However, no standard testing method for ANR headsets has emerged. In this study, we measured insertion losses of four types of commercially available ANR headsets using an Acoustic Test Fixture (ATF) to examine the feasibility of using ATF for this kind of measurement. The meas...

In medical imaging for clinical diagnosis and biomedical research magnetic resonance imaging (MRI) is one of the prevailing techniques. A lot of subjects of MRI are annoyed by the loud noise that MRI generates. In the present study computer simulation of active control of the noise induced by MRI was performed. The sound generated by the measurement sequences for the brain was recorded with an ...

Background: Noise mapping in industry can be useful to assess the risks of harmful noise, or to monitor noise in machine rooms. Using GIS -based software for plot of noise maps in an indoor noisy work environment can be helpful for occupational hygienists to monitor noise pollution. Methods: This study was carried out in noisy packaging unit of a food industry in Ghazvin industrial zone, to ev...

This paper presents the comparative performance analysis of two adaptive algorithms to control the attenuation of acoustic noise. Active noise control (ANC) is one of the most popular applications for adaptive filters. The basic idea behind the active control of acoustic noise is to inject a secondary sound (anti-noise) into an environment so as to cancel the primary sound using destructive int...

Statistically optimized near field acoustic holography (SONAH) is usually based on the assumption that all sources are on one side of the measurement plane whereas the other side is source free. An extension of the SONAH procedure based on measurement with an array of pressure-velocity probes has recently been suggested. An alternative method uses a double layer array of pressure transducers. B...

Remote distribution of optical frequency references, based on multifrequency sources such as femtosecond frequency combs, holds many advantages over its single-frequency counterpart. However, characterizing the excess noise caused by the transmission links or external perturbations in a multifrequency scheme posts new challenges. We have experimentally demonstrated direct measurement of excess ...

Functional magnetic resonance imaging (fMRI) studies involve substantial acoustic noise. This review covers the difficulties posed by such noise for auditory neuroscience, as well as a number of possible solutions that have emerged. Acoustic noise can affect the processing of auditory stimuli by making them inaudible or unintelligible, and can result in reduced sensitivity to auditory activatio...

A computationally eecient approach to the automatic segmentation (labeling) of noise disturbed speech is presented. The segmentation algorithm employs short term spectrum based feature vectors and a subspace representation of the sound classes. The two sound classes of vowels and unvoiced frica-tives are trained with the TIMIT acoustic phonetic continuous speech corpus. The sound class detector...