INTEC Acoustics
Soundscapes and perception models
The purpose of this research line is to increase the understanding of the complex phenomena involved in perception and appraisal of external stimuli by constructing computational models based on available knowledge at a lower level of abstraction and investigating the outcome of such simulation. The envisaged human information processing models have a different focus than perception models aiming at e.g. speech recognition or good old fashioned artificial intelligence. For one, they are probably not the most efficient way of performing an human-like task on todays computer infrastructures. Nevertheless they may eventually lead to alternative ways of approaching such practical tasks.
Our research -a few examples are shown below- starts at a slightly more abstract and less biological level than neuro-informatics or studies of the auditory pathway generally do. These underlying systems nevertheless are a very fruitfull source of inspiration.
A notice-event model for noise annoyance
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How often do we actually notice environmental sound during our everyday life? Is it true that the more you notice the environmental sound the more you get annoyed by it? An answer to these questions can be provided by our notice-event model. This model traces exposure to environmental noise from different sources taking into account the situational context that is created by instanteneous activities of the modelled individual (MI) to estimate how often and how long each sound is noticed. The model relies on known psycho-acoustic and psychological phenomena which are all implemented as simplified mathematical formulas. When run for a population of diverse individuals, trends emerge that are also observed in noise annoyance surveys. E.g. differences in noise annoyance caused by highways and railways (the railway bonus).
The notice-event model and combined noise exposure
Another application of the notice-event model that is currently under investigation is the perception and appraisal of a multi environmental noise source environment. Of particular importance in modelling the effect of combined exposure is the attention focussing and habituation / adaptation part of the model. In situations where listening to environmental sound is more active such as during recreational visits to parks and natural areas, these adaptations are useful if not essential to model human soundcape perception accurately.
Associating meaning
The meaning associated to perception of the environment (in particular to hearing an environmental sound) is an important factor in its appraisal. Modelling the process used by people to associate meaning to such a stimulus in a given context is still in its early stages. In a learning phase, the model extracts fundamental relationships between concepts. Later, the fully educated model will react to stimuly depending on whether they match expectations. Inspiration for this model is found in recent developments in simulation thought.
Environmental soundscape research is an active topic at INTEC's Acoustics Group. In particular, new methods to take into account the temporal variations in the soundscape are studied. Below you will find some explanation on various parts of this research.
What are Soundscapes?
The term soundscape generally refers to a sonic environment (natural, rural, urban...), with a strong emphasis on how it is perceived by the observer. Since this concept was introduced in the late 1960's from an artistic point of view, it raised the interest of researchers all over the world. Soundscape research has now become an interdisciplinary field of science, bringing together acousticians and physicists, as well as psychologists, biologists, sociologists and researchers of numerous other fields.
Music in the temporal structure
A prerequisite for assessing temporal aspects of soundscapes are suitable physical indicators, able to grasp the special characteristics of a time-varying soundscape, and which have a clear relation to human perception. Our group has worked on a novel indicator, called music-likeness, which measures how well the temporal structure of the soundscape corresponds with that commonly found in music. The leitmotiv is the echo into the soundscape of the typical complex systems that form its sound sources.