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Publications
Presentations and technical papers that have been presented by Norsonic at sound and vibrations conferences.
August 2024, Inter-Noise
A comparative study of noise event identification using AI in unattended monitoring
This paper explores the use of multi-microphone devices and artificial intelligence (AI) for identifying noise events in unattended noise monitoring. The primary focus is to assess the reliability of a machine learning model initially trained on a dataset representing a particular soundscape. We evaluate the performance of this model when applied to diverse datasets collected from similar yet distinct soundscapes, encompassing various environmental conditions and noise profiles. Through comparative analysis, we determine the model’s adaptability and potential limitations. The findings of this study offer insights into how well AI-based noise event identification models can work in different situations. This lays the groundwork for enhancing their applicability in diverse real-world settings and improving how well unattended noise monitoring systems function.
Authors: Karl Henrik Ejdfors and Naru Sato, Norsonic AS, Lars Andreas Sæle, Norconsult Norge AS
August 2024, Inter-Noise
Consideration and case study using a time-difference-of-arrival directional device for occupational noise measurement
To protect worker’s hearing in noisy workplaces, noise levels are measured periodically, and noise sources are located based on the results of recordings or video cameras. If the noise level is above a criterion level, noise abatement measures are taken, or workers are suggested to wear hearing protection. Measuring the noise level can be done simply by placing a sound level meter on the floor, but finding the noise abatement is a time-consuming task. It is necessary to listen to
the recordings one by one or review the video to find the noise abatement. We believe that a simple method of estimating noise abatement is very useful, since some noisy workplaces do not allow recordings or video cameras for privacy and confidentiality reasons. In this paper, noise source identification using a time-difference-of-arrival directional device in an indoor environment is examined. The results are analyzed in the context of room properties such as reverberation time, dimensions, and device localization. The paper also reports on practical usecases in actual sites.
Authors: Naru Sato, Karl Henrik Ejdfors and Erlend Fasting, Norsonic AS, Takeshi Nakaichi, RION Co., ltd. and Lars Andreas Sæle, Norconsult Norge
August 2024, Inter-Noise
Partial equivalent sound pressure level as an approach to manage irrelevant sounds in environmental noise measurements
Residual sound and unwanted events are known factors affecting the accuracy of environmental noise measurements. ISO 1996-2 provides methods to manage these irrelevant sounds, for example by applying correction factors, but the methods require a degree of knowledge of the irrelevant sounds that is not always practical or possible to obtain when performing long-term measurements with unattended monitoring stations in complex urban soundscapes. While
automatic detection of irrelevant sounds provides the required information, it also allows for new approaches not described in ISO 1996-2. In this paper, we discuss a metric called partial equivalent sound pressure level (Partial Leq), calculated after data samples with residual sound and unwanted events are identified automatically and replaced by project-specific values. Our hypothesis is that better estimates of equivalent sound pressure levels (Leq) can be achieved with this metric, compared with the general methods given in ISO 1996-2. Comparisons of results are presented, together with a discussion of applicability of the Partial Leq metric and experiences gathered from its use.
Authors: Daniela Toledo and Trond Iver Pedersen, Norsonic AS
August 2023, Inter-Noise
Automatic detection of source direction and exclusion of irrelevant sounds in unattended noise monitoring systems
A device featuring 8 MEMS microphones has been designed, which allows localizing dominant sound sources in 3D space by implementing techniques based on time difference of arrival. The device, also called Noise Compass, is intended to be used together with an outdoor measurement microphone in a noise monitoring terminal. By defining regions of interest in the vertical and horizontal planes in a monitoring and analysis system, non-relevant sounds can be automatically detected and excluded from the noise measurements. This article describes the direction detection mechanisms and shows two examples of system application: aircraft noise monitoring and a construction site with a road and railway nearby. Finally, other system applications are discussed.
Authors: Daniela Toledo and Erlend Fasting, Norsonic AS
