Showing papers on "Noise published in 2011"

Experimental evidence for real-time song frequency shift in response to urban noise in a passerine bird

Abstract: Research has shown that bird songs are modified in different ways to deal with urban noise and promote signal transmission through noisy environments. Urban noise is composed of low frequencies, th...

User-specific noise suppression for voice quality improvements

Abstract: Systems, methods, and devices for user-specific noise suppression are provided. For example, when a voice-related feature of an electronic device is in use, the electronic device may receive an audio signal that includes a user voice. Since noise, such as ambient sounds, also may be received by the electronic device at this time, the electronic device may suppress such noise in the audio signal. In particular, the electronic device may suppress the noise in the audio signal while substantially preserving the user voice via user-specific noise suppression parameters. These user-specific noise suppression parameters may be based at least in part on a user noise suppression preference or a user voice profile, or a combination thereof.

A Pitch Estimation Filter robust to high levels of noise (PEFAC)

Abstract: We present PEFAC, a fundamental frequency estimation algorithm that is able to identify the pitch of voiced frames reliably even at negative signal to noise ratios. The algorithm combines non-linear amplitude compression, to attenuate narrow-band noise components, with a comb-filter applied in the log-frequency power spectral domain, whose impulse response is chosen to attenuate smoothly varying noise components. We compare the performance of our algorithm with that of other widely used algorithms on a subset of the TIMIT database and demonstrate that it performs exceptionally well in both high and low levels of additive noise.

Anthropogenic noise affects song structure in red-winged blackbirds (Agelaius phoeniceus)

Abstract: Anthropogenic noise can mask animal signals that are crucial for communicating information about food, predators and mating opportunities. In response to noise masking, signallers can potentially improve acoustic signal transmission by adjusting the timing, frequency or amplitude of their signals. These changes can be a short-term modification in response to transient noise or a long-term modification in response to chronic noise. An animal's ability to adapt to anthropogenic noise can be crucial to its success. In this study, we evaluated the effects of anthropogenic noise on the structure of red-winged blackbird song. First, we manipulated the presence of anthropogenic noise by experimentally broadcasting either silence or low-frequency white noise to subjects inhabiting quiet marshes located away from roadsides. Subjects exhibited increased signal tonality when temporarily exposed to low-frequency white noise, suggesting that red-winged blackbirds can alter their signals rapidly in response to sudden noise. Second, we compared songs produced in quiet marshes located away from roadsides with songs produced during quiet periods at roadside marshes that are normally noisy. This allowed us to test whether birds that are exposed to chronic anthropogenic noise exhibit altered song structure during temporarily quiet periods. Subjects residing in roadside marshes that are normally polluted with anthropogenic noise sang songs with increased tonality during quiet periods. Overall, our results show that anthropogenic noise influences the structure of birdsong. These effects should be considered in conservation and wildlife management.

Effect of Stimulation Rate on Cochlear Implant Users’ Phoneme, Word and Sentence Recognition in Quiet and in Noise

Abstract: High stimulation rates in cochlear implants (CI) offer better temporal sampling, can induce stochastic-like firing of auditory neurons and can increase the electric dynamic range, all of which could improve CI speech performance. While commercial CI have employed increasingly high stimulation rates, no clear or consistent advantage has been shown for high rates. In this study, speech recognition was acutely measured with experimental processors in 7 CI subjects (Clarion CII users). The stimulation rate varied between (approx.) 600 and 4800 pulses per second per electrode (ppse) and the number of active electrodes varied between 4 and 16. Vowel, consonant, consonant-nucleus-consonant word and IEEE sentence recognition was acutely measured in quiet and in steady noise (+10 dB signal-to-noise ratio). Subjective quality ratings were obtained for each of the experimental processors in quiet and in noise. Except for a small difference for vowel recognition in quiet, there were no significant differences in performance among the experimental stimulation rates for any of the speech measures. There was also a small but significant increase in subjective quality rating as stimulation rates increased from 1200 to 2400 ppse in noise. Consistent with previous studies, performance significantly improved as the number of electrodes was increased from 4 to 8, but no significant difference showed between 8, 12 and 16 electrodes. Altogether, there was little-to-no advantage of high stimulation rates in quiet or in noise, at least for the present speech tests and conditions.

Method and apparatus for reducing the effect of environmental noise on listeners

Abstract: A method and apparatus for enhancing a desired audio signal for delivery through an electroacoustic channel include obtaining a noise estimate attributable to an external disturbance, applying the noise estimate to a dynamic noise compensation (DNC) process to thereby condition the desired audio signal as a function of the spectral characteristics of the noise estimate, applying the noise estimate to an adaptive equalization (AEQ) process to thereby condition the desired audio signal as a function of the electroacoustic response of the electroacoustic channel, and applying the noise estimate to an active noise cancelation (ANC) process configured to generate anti-noise for delivery into the electroacoustic channel.

Geotagged and weighted environmental audio for enhanced speech recognition accuracy

Abstract: Enhancing noisy speech recognition accuracy by receiving geotagged audio signals that correspond to environmental audio recorded by multiple mobile devices in multiple geographic locations, receiving an audio signal that corresponds to an utterance recorded by a particular mobile device, determining a particular geographic location associated with the particular mobile device, selecting a subset of geotagged audio signals and weighting each geotagged audio signal of the subset based on whether the respective audio signal was manually uploaded or automatically updated, generating a noise model for the particular geographic location using the subset of weighted geotagged audio signals, where noise compensation is performed on the audio signal that corresponds to the utterance using the noise model that has been generated for the particular geographic location.

Urban noise and male density affect songs in the great tit Parus major

Abstract: Since ambient noise interferes with sound transmission, urban noise can affect the acoustic structure of birdsong. Previous studies have examined song features (e.g. high minimum frequency) in urbanised areas; however, these studies did not exclude the effects of other factors. For example, the intensity of male–male competition is known to affect song structure. In 22 urban parks in Tokyo, Japan, we measured the effects of noise level and male density, an indicator of the intensity of competition among males, and examined the relationship between these factors (noise and male density) and song structure of the great tit, Parus major. We found that males in noisier parks sang songs with higher minimum frequencies, more phrases and longer durations. The frequency shift appeared to mitigate the acoustic masking of songs by low-frequency background noise, as has been shown in previous studies. Songs with repeated phrases and of longer duration are likely to be more detectable for receivers under noisy condit...

Hybrid audio delivery system and method therefor

Abstract: Methods and systems to produce audio output signals from audio input signals. In one embodiment, a first portion of the audio input signals can be pre-processed, with the output used to modulate ultrasonic carrier signals, thereby producing modulated ultrasonic signals. The modulated ultrasonic signals can be transformed into a first portion of the audio output signals, which is directional. Based on a second portion of the audio input signals, a standard audio speaker can output a second portion of the audio output signals. Another embodiment further produces distortion compensated signals based on the pre-processed signals. The distortion compensated signals can be subtracted from the second portion of the audio input signals to generate inputs for the standard audio speaker to output the second portion of the audio output signals. In yet another embodiment, noise can be added during pre-processing of the first portion of the audio input signals.

A threatened beluga (Delphinapterus leucas) population in the traffic lane: Vessel-generated noise characteristics of the Saguenay-St. Lawrence Marine Park, Canada

Abstract: The threatened resident beluga population of the St. Lawrence Estuary shares the Saguenay-St. Lawrence Marine Park with significant anthropogenic noise sources, including marine commercial traffic and a well-established, vessel-based whale-watching industry. Frequency-dependent (FD) weighting was used to approximate beluga hearing sensitivity to determine how noise exposure varied in time and space at six sites of high beluga summer residency. The relative contribution of each source to acoustic habitat degradation was estimated by measuring noise levels throughout the summer and noise signatures of typical vessel classes with respect to traffic volume and sound propagation characteristics. Rigid-hulled inflatable boats were the dominant noise source with respect to estimated beluga hearing sensitivity in the studied habitats due to their high occurrence and proximity, high correlation with site-specific FD-weighted sound levels, and the dominance of mid-frequencies (0.3–23 kHz) in their noise signatures. Median C-weighted sound pressure level (SPLRMS) had a range of 19 dB re 1 μPa between the noisiest and quietest sites. Broadband SPLRMS exceeded 120 dB re 1 μPa 8–32% of the time depending on the site. Impacts of these noise levels on St. Lawrence beluga will depend on exposure recurrence and individual responsiveness.

Audio segmentation of broadcast news in the Albayzin-2010 evaluation: overview, results, and discussion

Abstract: Recently, audio segmentation has attracted research interest because of its usefulness in several applications like audio indexing and retrieval, subtitling, monitoring of acoustic scenes, etc. Moreover, a previous audio segmentation stage may be useful to improve the robustness of speech technologies like automatic speech recognition and speaker diarization. In this article, we present the evaluation of broadcast news audio segmentation systems carried out in the context of the Albayzin-2010 evaluation campaign. That evaluation consisted of segmenting audio from the 3/24 Catalan TV channel into five acoustic classes: music, speech, speech over music, speech over noise, and the other. The evaluation results displayed the difficulty of this segmentation task. In this article, after presenting the database and metric, as well as the feature extraction methods and segmentation techniques used by the submitted systems, the experimental results are analyzed and compared, with the aim of gaining an insight into the proposed solutions, and looking for directions which are promising.

Anti-noise earmuff device with Bluetooth module and audio signal processor

Abstract: An anti-noise earmuff device includes an audio signal processor unit, a Bluetooth module, an audio mixer unit and an amplifier unit. The audio signal processor unit is arranged in the earmuffs for control audio signal output, protecting the user's eardrums against noise of high-decibel level. The Bluetooth module receives or communicates with a mobile communication device through an antenna, allowing the user to listen to the music and to communicate with people outside without needing taking off the earmuff device.

Audio watermarking robust against D/A and A/D conversions

Abstract: Digital audio watermarking robust against digital-to-analog (D/A) and analog-to-digital (A/D) conversions is an important issue. In a number of watermark application scenarios, D/A and A/D conversions are involved. In this article, we first investigate the degradation due to DA/AD conversions via sound cards, which can be decomposed into volume change, additional noise, and time-scale modification (TSM). Then, we propose a solution for DA/AD conversions by considering the effect of the volume change, additional noise and TSM. For the volume change, we introduce relation-based watermarking method by modifying groups of the energy relation of three adjacent DWT coefficient sections. For the additional noise, we pick up the lowest-frequency coefficients for watermarking. For the TSM, the synchronization technique (with synchronization codes and an interpolation processing operation) is exploited. Simulation tests show the proposed audio watermarking algorithm provides a satisfactory performance to DA/AD conversions and those common audio processing manipulations.

A pitch based noise estimation technique for robust speech recognition with Missing Data

Abstract: This paper presents a noise estimation technique based on knowledge of pitch information for robust speech recognition. In the first stage the noise is estimated by means of extrapolating the noise from frames where speech is believed to be absent. These frames are detected with a proposed pitch based VAD (Voice Activity Detector). In the second stage the noise estimation is revised in voiced frames using harmonic tunnelling thechnique. The tunnelling noise estimation is used at high SNRs as an upper bound of the noise rather than a suitable estimation. A spectrogram MD (Missing Data) recognition system is chosen to evaluate the proposed noise estimation. The proposed system is compared in Aurora-2 with other similar techniques like cepstral SS (Spectral Subtraction).

Age-related benefits of digital noise reduction for short-term word learning in children with hearing loss.

Abstract: Purpose To determine the rate of word learning for children with hearing loss (HL) in quiet and in noise compared to normal-hearing (NH) peers. The effects of digital noise reduction (DNR) were exa...

Noise exposure assessment in a dental school.

Abstract: Objectives: This cross-sectional study was performed in the Dental School of Prince of Songkla University to ascertain noise exposure of dentists, dental assistants, and laboratory technicians. A noise spectral analysis was taken to illustrate the spectra of dental devices. Methods: A noise evaluation was performed to measure the noise level at dental clinics and one dental laboratory from May to December 2010. Noise spectral data of dental devices were taken during dental practices at the dental services clinic and at the dental laboratory. A noise dosimeter was set following the Occupational Safety and Health Administration criteria and then attached to the subjects’ collar to record personal noise dose exposure during working periods. Results: The peaks of the noise spectrum of dental instruments were at 1,000, 4,000, and 8,000 Hz which depended on the type of instrument. The differences in working areas and job positions had an influence on the level of noise exposure (p < 0.01). Noise measurement in the personal hearing zone found that the laboratory technicians were exposed to the highest impulsive noise levels (137.1 dBC). The dentists and dental assistants who worked at a pedodontic clinic had the highest percent noise dose (4.60 ± 3.59%). In the working areas, the 8-hour time-weighted average of noise levels ranged between 49.7-58.1 dBA while the noisiest working area was the dental laboratory. Conclusion: Dental personnel are exposed to noise intensities lower than occupational exposure limits. Therefore, these dental personnel may not experience a noise-induced hearing loss.

Implementation of Direct Sequence Spread Spectrum steganography on audio data

Abstract: Image steganography has widely developed. There are also many algorithm developed for it. Meanwhile, the interest in using audio data as cover object in steganography can be spelled out late emergence than image data. This paper discusses the implementation of steganography in audio data using Direct Sequence Spread Spectrum method. Spread Spectrum method is often used to send hidden message through radio waves. This message is transmitted through noise-like wave. The same method can be applied to embed message in audio data. The embedded audio data will be heard as noise. The Spread Spectrum method used in this paper is Direct Sequence Spread Spectrum. A key is needed to embed messages into noise, this key is used to generate pseudo-noise wave. The information to be embedded must first modulated using the pseudo-noise. This paper discusses implementation of the method in audio data to hide text message. Spread Spectrum method is known to be very robust, but as a consequence the cost is very large, the implementation is relatively complex, and the information capacity is very limited. This problem will also be discussed in this paper.

The challenge of localizing vehicle backup alarms: effects of passive and electronic hearing protectors, ambient noise level, and backup alarm spectral content.

Abstract: A human factors experiment employed a hemi-anechoic sound field in which listeners were required to localize a vehicular backup alarm warning signal (both a standard and a frequency-augmented alarm) in 360-degrees azimuth in pink noise of 60 dBA and 90 dBA. Measures of localization performance included: (1) percentage correct localization, (2) percentage of right--left localization errors, (3) percentage of front-rear localization errors, and (4) localization absolute deviation in degrees from the alarm's actual location. In summary, the data demonstrated that, with some exceptions, normal hearing listeners' ability to localize the backup alarm in 360-degrees azimuth did not improve when wearing augmented hearing protectors (including dichotic sound transmission earmuffs, flat attenuation earplugs, and level-dependent earplugs) as compared to when wearing conventional passive earmuffs or earplugs of the foam or flanged types. Exceptions were that in the 90 dBA pink noise, the flat attenuation earplug yielded significantly better accuracy than the polyurethane foam earplug and both the dichotic and the custom-made diotic electronic sound transmission earmuffs. However, the flat attenuation earplug showed no benefit over the standard pre-molded earplug, the arc earplug, and the passive earmuff. Confusions of front-rear alarm directions were most significant in the 90 dBA noise condition, wherein two types of triple-flanged earplugs exhibited significantly fewer front-rear confusions than either of the electronic muffs. On all measures, the diotic sound transmission earmuff resulted in the poorest localization of any of the protectors due to the fact that its single-microphone design did not enable interaural cues to be heard. Localization was consistently more degraded in the 90 dBA pink noise as compared with the relatively quiet condition of the 60 dBA pink noise. A frequency-augmented backup alarm, which incorporated 400 Hz and 4000 Hz components to exploit the benefits of interaural phase and intensity cues respectively, slightly but significantly improved localization compared with the standard, more narrow-bandwidth backup alarm, and these results have implications for the updating of backup alarm standards.

Noise suppressing device

Abstract: A noise suppressing device is provided for suppressing noise of a first audio signal to generate a second audio signal. In the noise suppressing device, a noise acquisition unit acquires a plurality of noise components which are different from each other. A noise suppression unit generates each suppression component by suppressing each noise component from the first audio signal, thereby providing a plurality of suppression components different from each other in correspondence to the plurality of the noise components. A signal generation unit generates the second audio signal by summing the plurality of the suppression components that are provided from the noise suppression unit.

Improved Audio Watermarking Using DWT-SVD

Abstract: Digital audio watermarking involves the concealment of data within a discrete audio file. Applications for this technology are numerous. Intellectual property protection is currently the main driving force behind research in this area. In this paper we present an ef- ficient audio watermarking algorithm in the frequency domain by embedding an inaudible audio water mark. Comparison of two different algorithms i.e. Discrete Cosine Transform (DCT)-Singular Value Decomposition (SVD) and Discrete Wavelet Transform (DWT)-SVD is presented here. The effectiveness of these algorithms is verified by conducting experimentation. Experimental results show that the wa- termarked audio has good imperceptibility and is robust against different kinds of attacks, such as noise adding, re-sampling, cropping.

Robust dual-channel noise power spectral density estimation

Abstract: In this paper, we propose a novel noise power spectral density (PSD) estimator which is beneficial for speech enhancement systems with two microphones in diffuse noise environments. The algorithm has a low computational complexity and requires low memory usage. The main advantage is that arbitrary models of the noise field coherence can be employed and a scalable extension of existing single-channel speech enhancement systems to dual channels is also possible. Experiments demonstrate with simulated and measured data that the proposed algorithm outperforms related algorithms in diffuse noise conditions.

Masking by a remote-frequency noise band in children and adults.

Abstract: OBJECTIVE Werner and Bargones (1991) observed that a 4-10-kHz noise band can mask a 1-kHz signal during infancy. The purpose of this study was to examine whether remote-noise masking extends into the school-aged years. DESIGN Listeners were 4-6-yr-olds, 7-9-yr-olds, and adults. Detection thresholds were measured for the 1-kHz signal in quiet and in the presence of the remote-frequency noise. In separate conditions, masker level was either 40 or 60 dB SPL. RESULTS On average, thresholds for the 1-kHz signal were elevated in the presence of the remote-frequency noise for 4-6-yr-olds, but not for 7-9-yr-olds or adults. Group average thresholds were similar across masker levels, indicating nonperipheral effects. CONCLUSIONS Susceptibility to remote-frequency masking in children extends to 4-6 yrs of age for some children.

Voice denoising method based on audio recognition

Abstract: The invention provides a speech noise reduction method based on audio recognition, which reduces the noise of a receiving end by aiming at the speech communication under complex noise environment, belonging to the field of computer science and technology. Most of the existing noise reduction methods are only suitable for stable noise environment and can not remove the noise under the situations of complex noise environment, especially the situation of frequent mutagenicity noise and the like. The method leads a mode recognition idea in the communication speech noise reduction, divides an audio signal into a speech signal and a non-speech signal, automatically identifies the input signal by extracting the speech characteristic and designing a sorter model, and judges the audio type; if theaudio type is noise, the audio signal is removed; if the audio type is speech, the audio signal is remained and processed further. The method meets the real-time requirement and has better reduction noise effect at the same time, can be suitable for the situations with complex communication environments such as manned spaceflight speech communication, construction sites, battlefields and the like, and provides an idea and a method for the noise reduction of signals.