3 Questions for Dr Franz Graf...

3 Questions for DI Dr Franz Graf on Acoustic Sensor Technologies

Dr Franz Graf in the motorway tunnel equipped with acoustic sensors, Credit: JOANNEUM RESEARCH/ Bergmann

DI Dr Franz Graf is the head of the Intelligent Acoustic Solutions research group at the DIGITAL Institute.


What are the advantages of acoustic sensor technologies compared to other sensor technologies?

The "artificial" reproduction of human perception and its senses is one of the great goals of us researchers. The technical counterpart of the sense of hearing is acoustic sensors. These have many technological advantages and - as with human perception - complement the other senses, or rather the sensors.

Unlike video cameras, acoustic sensors allow you to "hear around the corner". They work in darkness, fog and smoke just as well as in fine weather and backlighting. These are very crucial properties in real-life applications and 24/7 operation. Furthermore, they are very small, inexpensive and the bandwidth of the signals is lower than, for example, with video cameras, which also makes it easier to process audio signals with embedded systems or in larger numbers in parallel using artificial intelligence.

What successes can you report from AKUT, the acoustic tunnel monitoring?

We are currently operating AKUT in 30 road tunnels with about 1,800 microphones with a tube length of more than 144 km. That roughly corresponds to the distance from Graz to Wiener Neustadt. By quickly detecting critical events, we have been able to help minimise the impact of many accidents in tunnels in recent years. The last major fire in the Gleinalm Tunnel in autumn 2018 was also first reported by AKUT.

In accordance with the framework agreement with ASFINAG, another 26 tunnels will follow by 2029, which means that we will operate about 3,500 microphones in Austria in the final stage. But we are also active abroad despite the worldwide pandemic: for example, we are about to commission the first installation in the Czech Republic.

How did you originally come to your profession?

As with most acousticians, the path to acoustics leads through music. That was also the case for me. After my A-levels at an HTBL for electrical engineering and my military service, I had the choice between a musical-artistic and a technical career. I then decided to study electrical engineering and sound engineering in order to be able to combine both worlds. In the end, the technical path I chose became established in the course of my studies. But music still plays an important role in my life - even if it is now "only" my favourite hobby and not my profession.