The development of acoustic imaging methods must meet the issue of reverberant environments. For the analysis of pathways, photoacoustic tomography (PAT) is a traditional method firstly conducted on a bus prototype, then tested to determine its relevance as a more operational method.
New tools are needed to integrate these technologies in order to validate their robustness and efficiency with the development of the two prototypes. This methods analysis coupled to the development of local models is able to better define noise reduction solutions.
The specific goal of this project is to integrate acoustics in these application fields to provide a high level of passenger comfort, thus facilitating the use of public transport, and a harmonious sound environment for local residents. The proposed approach relied on an experimental approach aimed to pursue technological innovations and implementation of local models to define solutions.
The proposed experimental approach was mostly based on a acoustic imaging technique and present two innovative aspects. The first one was to develop one (or more) imaging methods employable inside a cabin without being disturbed by glare. This required algorithmic developments and technological innovations for results visualization. The second innovation concerned the transfer paths identification techniques. The objective was to develop a much faster method than the traditional method called "PAT" to lead to industrial use of this method.
The new interior imaging tool developed by MicrodB within this project incorporated a dual-sphere patented system associated with a method of "Multiplicative spherical beamforming".
New architectures were tested and improved, such as back door, change rear glazing, and others. Concerning the external noise, an acoustic imaging tool developed by MicrodB did not bring really interesting information for Irisbus; however, Irisbus has developed a tool incorporating the telemetry which synchronized a system boarded on the bus to measure external noise standard pass. The correlation of these two entries leaded to an improved results interpretation.
The identification methodology of acoustic sources developed in the project resulted in significant time savings in the interior design about noise sources (cockpit, cabin, in railway compartment, automotive, aeronautics, etc.). MicrodB sold this method effectively through the services of the product. Addressed tracks such improved propagation models, coupling methods are areas of development that the LVA and MicrodB continues to explore.