Processing Of Environmental Sounds Research Articles

Signal acquisition system based on wireless transmission for environmental sound monitoring system

In today’s technological era, the ability to access information through digital signals, especially voice, requires sophisticated and comprehensive applications that can convert physical signals into electrical signals. Its purpose is to assist humans in displaying and analysing structured and automated data obtained from tools with their unique set of features. In this study, we used signal data for different sounds, such as rock songs, birdsong, acoustic sounds, and conversational sounds. The data is checked using software and undergoes a data acquisition process. The results of the study are expected to reinforce that environmental sound processing is predicted to assist the development of more sophisticated automated monitoring systems capable of combining voice and visual data in a complementary way.

Crossmodal processing of environmental sounds and everyday life actions: An ERP study

To investigate the processing of environmental sounds, previous researchers have compared the semantic processing of words and sounds, yielding mixed results. This study aimed to specifically investigate the electrophysiological mechanism underlying the semantic processing of environmental sounds presented in a naturalistic visual scene. We recorded event-related brain potentials in a group of young adults over the presentation of everyday life actions that were either congruent or incongruent with environmental sounds. Our results showed that incongruent environmental sounds evoked both a P400 and an N400 effect, reflecting sensitivity to physical and semantic violations of environmental sounds’ properties, respectively. In addition, our findings showed an enhanced late positivity in response to incongruous environmental sounds, probably reflecting additional reanalysis costs. In conclusion, these results indicate that the crossmodal processing of the environmental sounds might require the simultaneous involvement of different cognitive processes.

Basic auditory skills evaluation battery for online testing of cochlear implant users

Cochlear implant (CI) performance varies considerably across domains of auditory function, but clinical testing is typically restricted to speech intelligibility. Although other domains, including environmental sound and music perception or speech comprehension, are considered important to quality-of-life and personal safety, their adaptation into clinical use has been limited. The basic auditory skills evaluation (BASE) battery was developed to provide online access to such comprehensive assessment using the Internet as a test delivery platform. It includes 17 3–5 min tests to evaluate (1) basic spectro-temporal processing, (2) processing of environmental sounds and music, and (3) speech perception and comprehension in quiet and background noise. Two groups of 18 and 25 postlingual adult CI users were tested either at home following online instructions or in the lab by an audiologist. Results revealed a range of performance across tests from near ceiling to close to chance. No significant differences in group performance on any of the tests were observed, suggesting that BASE battery can assess a diverse array of abilities online, with varying difficulty levels. These findings provide preliminary support for the use of the test battery for an Internet-based comprehensive assessment of ecologically relevant aspects of auditory perception in adult CI users.

Activating Semantic Knowledge During Spoken Words and Environmental Sounds: Evidence From the Visual World Paradigm.

Two visual world experiments investigated the activation of semantically related concepts during the processing of environmental sounds and spoken words. Participants heard environmental sounds such as barking or spoken words such as "puppy" while viewing visual arrays with objects such as a bone (semantically related competitor) and candle (unrelated distractor). In Experiment 1, a puppy (target) was also included in the visual array; in Experiment 2, it was not. During both types of auditory stimuli, competitors were fixated significantly more than distractors, supporting the coactivation of semantically related concepts in both cases; comparisons of the two types of auditory stimuli also revealed significantly larger effects with environmental sounds than spoken words. We discuss implications of these results for theories of semantic knowledge.

Atypical Sound Perception in ASD Explained by Inter-Trial (In)consistency in EEG.

A relative indifference to the human voice is a characteristic of Autism Spectrum Disorder (ASD). Yet, studies of voice perception in ASD provided contradictory results: one study described an absence of preferential response to voices in ASD while another reported a larger activation to vocal sounds than environmental sounds, as seen in typically developed (TD) adults. In children with ASD, an absence of preferential response to vocal sounds was attributed to an atypical response to environmental sounds. To have a better understanding of these contradictions, we re-analyzed the data from sixteen children with ASD and sixteen age-matched TD children to evaluate both inter- and intra-subject variability. Intra-subject variability was estimated with a single-trial analysis of electroencephalographic data, through a measure of inter-trial consistency, which is the proportion of trials showing a positive activity in response to vocal and non-vocal sounds. Results demonstrate a larger inter-subject variability in response to non-vocal sounds, driven by a subset of children with ASD (7/16) who do not show the expected negative Tb peak in response to non-vocal sounds around 200 ms after the start of the stimulation due to a reduced inter-trial consistency. A logistic regression model with age and clinical parameters allowed demonstrating that not a single parameter discriminated the subgroups of ASD participants. Yet, the electrophysiologically-based groups differed on a linear combination of parameters. Children with ASD showing a reduced inter-trial consistency were younger and characterized by lower verbal developmental quotient and less attempt to communicate by voice. This data suggests that a lack of specialization for processing social signal may stem from an atypical processing of environmental sounds, linked to the development of general communication abilities. Discrepancy reported in the literature may arise from that heterogeneity and it may be inadequate to divide children with ASD based only on intellectual quotient or language abilities. This analysis could be a useful tool in providing complementary information for the functional diagnostic of ASD and evaluating verbal communication impairment.

Deep Learning for Audio Signal Processing

Given the recent surge in developments of deep learning, this article provides a review of the state-of-the-art deep learning techniques for audio signal processing. Speech, music, and environmental sound processing are considered side-by-side, in order to point out similarities and differences between the domains, highlighting general methods, problems, key references, and potential for cross-fertilization between areas. The dominant feature representations (in particular, log-mel spectra and raw waveform) and deep learning models are reviewed, including convolutional neural networks, variants of the long short-term memory architecture, as well as more audio-specific neural network models. Subsequently, prominent deep learning application areas are covered, i.e. audio recognition (automatic speech recognition, music information retrieval, environmental sound detection, localization and tracking) and synthesis and transformation (source separation, audio enhancement, generative models for speech, sound, and music synthesis). Finally, key issues and future questions regarding deep learning applied to audio signal processing are identified.

Environmental sound processing and its applications

As part of the effort to develop techniques for understanding environments using sound, many studies in the field of computational auditory scene analysis have focused on using computers to perform functions carried out naturally by the human auditory system. Thanks to recent progress in machine‐learning techniques, these environmental sound‐processing techniques have significantly improved and a widening variety of applications has resulted in considerable interest in this field. In this review, we introduce the fundamental techniques of environmental sound processing, as well as recent advances in front‐end and back‐end processing and potential applications for these techniques. Prospects for further progress in the field of environmental sound processing and the challenges still to be overcome are also discussed. © 2019 Institute of Electrical Engineers of Japan. Published by John Wiley & Sons, Inc.

Alternative Silver Production by Environmental Sound Processing of a Sulfo Salt Silver Mineral Found in Bolivia

Very often, the production of silver causes devastating environmental issues, because of the use of toxic reagents like cyanide and mercury. Due to severe environmental damage caused by humans in the last decades, the social awareness regarding the sustainable production processes is on the rise. Terms like “sustainable” and “green” in product descriptions are becoming more and more popular and producers are forced to satisfy the rising environmental awareness of their customers. Within this work, an alternative environmental sound silver recovery process was developed for a vein type silver ore from Mina Porka, Bolivia. A foregoing characterization of the input material reveals its mineral composition. In the following mineral processing, around 92.9% silver was concentrated by separating 59.5 wt. % of non-silver minerals. Nitric acid leaching of the generated concentrate enabled a silver recovery of up to 98%. The dissolved silver was then separated via copper cementation to generate a metallic silver product of >99% purity. Summarizing all process steps, a silver yield of 87% was achieved in lab scale. A final upscaling trial was conducted to prove the process’ robustness. Within this trial, almost 4 kg of metallic silver with a purity of higher than 99.5 wt. % was produced.

An open development platform for auditory real-time signal processing

Algorithms that are used in real-time hearing devices, such as hearing aids or cochlear implants, need to work with a short time latency in the order of 10 ms and must be efficient enough to run on battery power. Furthermore, in order to evaluate ecological validity such algorithms often need to be validated in the development stage using real-time processing of environmental sounds. However, researchers often lack the ability to access to the technology and they use offline schemes instead. In order to allow more and less specialised researchers access to the necessary technology and make it as easy and straightforward to develop real-time algorithm, we have developed an auditory real-time processing algorithm platform (“Open Development Platform”, ODP). The ODP is designed to help the development from existing offline algorithms to novel real-time algorithms by introducing a clear set of rules for development and evaluation. ODP has a software component that works in MATLAB/Simulink and a hardware component that works on the Speedgoat® Target machine. We also explain several algorithms from the available library that have low latency and low power consumption: filter bank, envelop power estimator, frequency shifter, and adaptive feedback canceller. As example of a complete project, we demonstrate here, how they can be combined to a fully functional hearing aid for research purposes.

Music as environment: an ecological and biosemiotic approach.

This paper provides an attempt to conceive of music in terms of a sounding environment. Starting from a definition of music as a collection of vibrational events, it introduces the distinction between discrete-symbolic representations as against analog-continuous representations of the sounds. The former makes it possible to conceive of music in terms of a Humboldt system, the latter in terms of an experiential approach. Both approaches, further, are not opposed to each other, but are complementary to some extent. There is, however, a distinction to be drawn between the bottom-up approach to auditory processing of environmental sounds and music, which is continuous and proceeding in real time, as against the top-down approach, which is proceeding at a level of mental representation by applying discrete symbolic labels to vibrational events. The distinction is discussed against the background of phylogenetic and ontogenetic claims, with a major focus on the innate auditory capabilities of the fetus and neonate and the gradual evolution from mere sensory perception of sound to sense-making and musical meaning. The latter, finally, is elaborated on the basis of the operational concepts of affordance and functional tone, thus bringing together some older contributions from ecology and biosemiotics.

On the spatial organization of sound processing in the human temporal lobe: A meta-analysis

In analogy to visual object recognition, proposals have been made that auditory object recognition is organized by sound class (e.g., vocal/non-vocal, linguistic/non-linguistic) and linked to several pathways or processing streams with specific functions. To test these proposals, we analyzed temporal lobe activations from 297 neuroimaging studies on vocal, musical and environmental sound processing. We found that all sound classes elicited activations anteriorly, posteriorly and ventrally of primary auditory cortex. However, rather than being sound class (e.g., voice) or attribute (e.g., complexity) specific, these processing streams correlated with sound knowledge or experience. Specifically, an anterior stream seemed to support general, sound class independent sound recognition and discourse-level semantic processing. A posterior stream could be best explained as supporting the embodiment of sound associated actions and a ventral stream as supporting multimodal conceptual representations. Vocalizations and music engaged these streams evenly in the left and right hemispheres, whereas environmental sounds produced a left-lateralized pattern. Together, these results both challenge and confirm existing proposal of temporal lobe specialization. Moreover, they suggest that the temporal lobe maintains the neuroanatomical building blocks for an all-purpose sound comprehension system that, instead of being preset for a particular sound class, is shaped in interaction with an individual's sonic environment.

The role of context in the perception of environmental sounds

Past work has shown involvement of context in the perception of sequences of meaningful speech sounds. The present study extended investigation to meaningful environmental sounds, evaluating the accuracy in identifying individual sources in sequences of five environmental sounds that were either likely or not to have occurred together in place and time. Rating of sequence coherence confirmed the subjective distinction between sequence types. In the main task, young normal-hearing listeners were instructed to identify and order each sound they heard by selecting from among 20 randomly selected labels. Listeners were significantly more accurate in reporting both the names and order of the sounds of the coherent sequences in which sounds were more likely to have occurred together. If not scored in terms of source order, a smaller but still significant difference was obtained between coherent and incoherent sequences. For both sequence types, there was a trend for best performance for the initial and final sources of the sequences. Overall, results are consistent with speech findings and demonstrate a positive effect of context in the perceptual processing of environmental sounds. [Work supported by NIH/NIDCD.]

Bilateral reorganization of posterior temporal cortices in post‐lingual deafness and its relation to cochlear implant outcome

Post-lingual deafness induces a decline in the ability to process phonological sounds or evoke phonological representations. This decline is paralleled with abnormally high neural activity in the right posterior superior temporal gyrus/supramarginal gyrus (PSTG/SMG). As this neural plasticity negatively relates to cochlear implantation (CI) success, it appears important to understand its determinants. We addressed the neuro-functional mechanisms underlying this maladaptive phenomenon using behavioral and functional magnetic resonance imaging (fMRI) data acquired in 10 normal-hearing subjects and 10 post-lingual deaf candidates for CI. We compared two memory tasks where subjects had to evoke phonological (speech) and environmental sound representations from visually presented items. We observed dissociations in the dynamics of right versus left PSTG/SMG neural responses as a function of duration of deafness. Responses in the left PSTG/SMG to phonological processing and responses in the right PSTG/SMG to environmental sound imagery both declined. However, abnormally high neural activity was observed in response to phonological visual items in the right PSTG/SMG, i.e., contralateral to the zone where phonological activity decreased. In contrast, no such responses (overactivation) were observed in the left PSTG/SMG in response to environmental sounds. This asymmetry in functional adaptation to deafness suggests that maladaptive reorganization of the right PSTG/SMG region is not due to balanced hemispheric interaction, but to a specific take-over of the right PSTG/SMG region by phonological processing, presumably because speech remains behaviorally more relevant to communication than the processing of environmental sounds. These results demonstrate that cognitive long-term alteration of auditory processing shapes functional cerebral reorganization.

Hearing living symbols and nonliving icons: Category specificities in the cognitive processing of environmental sounds

The neurocognitive processing of environmental sounds and linguistic stimuli shares common semantic resources and can lead to the activation of motor programs for the generation of the passively heard sound or speech. We investigated the extent to which the cognition of environmental sounds, like that of language, relies on symbolic mental representations independent of the acoustic input. In a hierarchical sorting task, we found that evaluation of nonliving sounds is consistently biased toward a focus on acoustical information. However, the evaluation of living sounds focuses spontaneously on sound-independent semantic information, but can rely on acoustical information after exposure to a context consisting of nonliving sounds. We interpret these results as support for a robust iconic processing strategy for nonliving sounds and a flexible symbolic processing strategy for living sounds.

Environmental sound processing: Distinct cortical regions for knowledge about furry, noisy Australian animals.

 Four conditions tapped into different types of object information, and within each of these conditions there were two possible questions relating to the heard sounds: 1. Visual perceptual question: Does it have fur? Is it made of metal? 2. Encyclopaedic question: Does it live in Australia? Is it a tool? 3. Categorical question: Is it living? Is it manmade? 4. Auditory perceptual question: Does the sound get louder? Does the sound get quieter?  There were 40 auditory stimuli in total (20 animals, 20 manmade objects, 1500ms duration), presented in mono through MR-compatible headphones. Determining the cortical regions engaged by environmental sounds has often been confined to the investigation of differences between meaningful and meaningless sounds1,2, speech and non-speech sounds3,4 or differences in semantic category membership,5,6,7. By comparing neuronal responses to different knowledge types for the same sounds, we expected to observe differential regions activated within the auditory object processing network and hypothesised that these would reflect the different types of information required to perform the task. The aim of this fMRI study was to compare and contrast a wider spectrum of different types of auditory object knowledge – perceptual, categorical and encyclopaedic – within the same experiment and using the same set of environmental sounds.

Infants' Recognition of Meaningful Verbal and Nonverbal Sounds

To examine how young children recognize the association between two different types of meaningful sounds and their visual referents, we compared 15-, 20-, and 25-month-old infants' looking time responses to familiar naturalistic environmental sounds (e.g., the sound of a dog barking) and their empirically matched verbal descriptions (e.g., “Dog barking”) in an intermodal preferential looking paradigm. Across all three age groups, performance was indistinguishable over the two domains. Infants with the largest vocabularies were more accurate in processing the verbal phrases than the environmental sounds. However, after taking into account each child's verbal comprehension/production and the onomatopoetic test items, all cross-domain differences disappeared. Correlational analyses revealed that the processing of environmental sounds was tied to chronological age, while the processing of speech was linked to verbal proficiency. Overall, while infants' ability to recognize the two types of sounds did not differ behaviorally, the underlying processes may differ depending on the type of auditory input.

Familiarity affects environmental sound processing outside the focus of attention: An event-related potential study

This study investigated the influence of the familiarity of an environmental sound on sound processing outside the focus of attention. By comparing ERPs elicited by a familiar, animal sound and an acoustically matched, but unfamiliar, complex sound, three issues were addressed: (a) general differences in the processing of the familiar and the unfamiliar sound, (b) influences of sound familiarity on the processing of deviants unrelated to familiarity and (c) familiarity-specific processing depending on the sound context. Participants watched a silent, subtitled movie. The familiar sound elicited a centro-parietal enhancement of the N1, a frontocentrally enhanced P2 and an additional P250. Auditory deviance processing elicited by deviants in sound location was not influenced by the familiarity of the sounds. However, after an involuntary switch of attention to the deviant, an N400-like deflection indicated enhanced semantic analysis of the familiar deviant. Familiarity-specific ERP effects as a consequence of the sound context occurred between 300 and 500 ms after stimulus onset. Whereas familiarity of an environmental sound elicited enhanced stimulus processing before 300 ms, influences of the sound context were observed subsequent to 300 ms. Familiarity of a complex environmental sound influences several stages of auditory processing outside the focus of attention.

Developmental phonagnosia: A selective deficit of vocal identity recognition

Phonagnosia, the inability to recognize familiar voices, has been studied in brain-damaged patients but no cases due to developmental problems have been reported. Here we describe the case of KH, a 60-year-old active professional woman who reports that she has always experienced severe voice recognition difficulties. Her hearing abilities are normal, and an MRI scan showed no evidence of brain damage in regions associated with voice or auditory perception. To better understand her condition and to assess models of voice and high-level auditory processing, we tested KH on behavioural tasks measuring voice recognition, recognition of vocal emotions, face recognition, speech perception, and processing of environmental sounds and music. KH was impaired on tasks requiring the recognition of famous voices and the learning and recognition of new voices. In contrast, she performed well on nearly all other tasks. Her case is the first report of developmental phonagnosia, and the results suggest that the recognition of a speaker's vocal identity depends on separable mechanisms from those used to recognize other information from the voice or non-vocal auditory stimuli.

Probing category selectivity for environmental sounds in the human auditory brain

Earlier studies reported evidence suggesting distinct category-related auditory representations for environmental sounds such as animal vocalizations and tool sounds in superior and middle temporal regions of the temporal lobe. However, the degree of selectivity of these representations remains to be determined. The present study combined functional magnetic resonance imaging (fMRI) adaptation with a silent acquisition protocol to further investigate category-related auditory processing of environmental sounds. To this end, we consecutively presented pairs of sounds taken from the categories ‘tool sounds’ or ‘animal vocalizations’ with either the same or different identity/category. We examined the degree of selectivity as evidenced by adaptation effects to both or only one sound category in the course of whole-brain as well as functionally and anatomically constrained region of interest analyses. While most regions predominately in the temporal cortex showed an adaptation to both sound categories, particularly the left superior temporal gyrus (STG) and the left posterior middle temporal gyrus (pMTG) selectively adapted to animal vocalizations and tool sounds, respectively. However, the activation profiles of these regions differed with respect to the general responsiveness to sounds. While tool sounds still produced fMRI signals significantly different from fixation baseline in the STG, this was not the case for animal vocalizations in pMTG. Consistent with the interpretation of STG as an intermediate auditory processing stage, this region might differentiate auditory stimuli into categories based on variations of physical stimulus properties. However, processing in left pMTG seems to be even more restricted to action-related sounds of man-made objects.

A developmental ERP study of verbal and non-verbal semantic processing

To clarify how different the processing of verbal information is from the processing of meaningful non-verbal information, the present study characterized the developmental changes in neural responses to words and environmental sounds from pre-adolescence (7–9 years) through adolescence (12–14 years) to adulthood (18–25 years). Children and adults' behavioral and electrophysiological responses (the N400 effect of event-related potentials) were compared during the processing of words and environmental sounds presented in semantically matching and mismatching picture contexts. Behavioral accuracy of picture–sound matching improved until adulthood, while reaction time measures leveled out by age 12. No major electrophysiological changes in the N400 effect were observed between pre-adolescence and adolescence. When compared to adults, children demonstrated significant maturational changes including longer latencies and larger amplitudes of the N400 effect. Interestingly, these developmental differences were driven by stimulus type: the Environmental Sound N400 effect decreased in latency from adolescence to adulthood, while no age effects were observed in response to Words. Thus, while the semantic processing of single words is well established by 7 years of age, the processing of environmental sounds continues to improve throughout development.