Acoustical Virtual Reality for automotive applications Seminar

Abstract

The traditional approach for sound recording and playing back in the automotive field has been dominated by the binaural approach for decades, providing additional "spatial" information which was lost using just omnidirectional microphones.

In the last few years an alternative approach emerged, driven by recent developments in the so-called "spatial  audio" technology employed for the emerging technology based on using Virtual Reality devices, such as panoramic cameras and stereoscopic visors.

Three methods are competing for providing "spatial audio" accompanying VR video footage: "Quad Binaural", "Ambisonics" and "Spatial PCM Sampling". The three methods differ mostly at the recording side, making use of different microphone arrays. However transcoding is possible, as creating purely virtual soundtracks (for example, as the result of computer simulations). The rendering is typically done using an HMD (Head mounted Display, such as an Oculus visor) and headphones, with head-tracked binaural rendering, which keeps the perceived position of sound source perfectly coherent with the visual rendering.

The seminar will provide the basics of the three methods, and of the transcoding technology required for converting from one to the other. Several examples will be presented, related to the automotive field, showing both recording and playback of audio and video tracks, both inside the cockpit or along the road, during the vehicle's pass-by.

Finally it will be shown how from Ambisonics, or, better, SPS recordings it is possible to obtain "objective" analysis of the sound field, by means of pseudo-color maps showing the spatial distribution of the sound intensity and of other psychoacoustically-relevant parameters such as Loudness, Roughness, Sharpness, Fluctuation Strength, etc.

Such continuously-changing pseudo-colors maps can be superposed to the panoramic video and displayed on the HMD, allowing to "see", and of course to hear, where disturbing noise is coming from.

Speaker Biography

• Angelo graduated at the University of Bologna in 1982 (5-years "laurea" degree in Civil Engineering );
• At the same University he got a Ph.D. in Technical Physics in 1987. In both cases the theses were about Applied Acoustics topics.
• In 1986 he became Researcher in Environmental Technical Physics , initially at the University of Bologna, and since March 1992 at the University of Parma.
• He became Associated Professor in Environmental Technical Physics on 1 November 1998 at the University of Parma, and since then he is holding courses of Technical Physics and Applied Acoustics at the faculties of Engineering, Architecture and Medicine.
• Since 1 May 2005 he is Full Professor in Environmental Technical Physics

Angelo conducted wide and deep research in almost all the fields of Acoustics, and particularly he worked on digital signal processing techniques for acoustical measurements and audio effects, and on numerical models for the sound field estimation in closed and open spaces.

Angelo has coded a lot of software for the design of theatres and concert halls, sound diffusion systems, workplaces and for the dimensioning of sound reduction devices both indoors and outdoors. Some of these programs were released as commercial software, published both in Italy and in other countries: at the beginning of 1993, RAMSETE was launched. It is a Pyramid Tracing program for the simulation of the sound propagation in closed spaces and outdoors. One year later, AURORA was released: it is a suite of software tools which makes it possible to measure impulse responses or to recover them from Ramsete simulations, and to use them as filters for making Virtual Acoustics Reality simulations (auralisations). The coupling of the two programs produces audible simulations (on headphones or a suitable set of loudspeaker) of the various design hypotheses, starting from anechoic speech, music or noise.

In the last few years, Angelo focused mostly on the usage of massive transducer arrays, for different applications: microphone arrays for sound recording in theatres and TV studios, hydrophone arrays for underwater acoustical imaging and passive sonar, loudspeaker arrays for emulating sound sources with a prescribed directivity and for reproducing sound waves inside confined spaces.

For processing these massive multichannel streams, Angelo developed a general approach, completely "theoryless", based on numerical inversion of many impulse responses measured on the array to be controlled.

Angelo is the author of 4 patents and almost 300 scientific papers , which are all made available in full text on the author's web site , as Angelo is a strong supporter of the Open Science movement, and a strong opponent of Bibliometrics , the dummy science which rates the work of a researcher mostly on where the results are published and how much they are cited inside the circuit of Scopus-indexed journals.