On Monday, 10th of September 2018, Philipp Bulling sucessfully defended his dissertation on speech enhancement for in-car communication systems. His work focused mainly on the control of adaptive feedback cancellation filters (details can be found here). After an excellent talk Philipp gave very good answers to the questions of the committee and at around 11:30 h everythings war over and we had a small celebration (thanks also to Philipp's parents for preparing that part of the defense). An finally of course: contratulations to Philipp - very well done!
Last Friday we clebrated our yearly summer event in combinantion with the summer meeting of the Gesellschaft für angewandte Signalverarbeitung e.V. First, the year was reviewed from the perspective of the professors (talk from Gerhard Schmidt), the Ph.D. students (talk from Finn Spitz), and the bachelor and master students (talk from Jonas Weiss and Alexander Wilbrandt). Afterwards Eric Elzenheimer (as beeing member of the executive Committee of GaS e.V.) handed over the price for the best thesis in the area of applied signal processing to Tobias Klawonn (congratulations once again). Finally, Michael Klein from the company Berner talked to the audience before we had our yearly barbecue and our get-together. This year also the weather was really nice, allowing us to stay outside until late night.
Anton and Alexej are ready now with the preparation of our new low-delay hardware for our embedded lab. The hardware, so-called bela boards, can handle up to 10 inputs and 10 outputs and can operate with a round-trip delay of about 1 ms. The boards are programmed in C/C++ and allow for very "nice" audio examples.
Currently we implement speech enhancement algorithms, anti-noise systems, and virtual reality approaches (in terms of "audio-only reality") as student projects using the boards.
If you are interested, have a look on the website of our new embedded lab that will start in the winter term 2018/2019.
On July, 19th we christened our (first) small ship. It got the name "MISSy", which stands for "MIMO SONAR System". We did this at the "Kitzeberger Strand". Beside having a small party due to the event, we also did several measurements. One of them was testing a first version of our underwater telephone system. One subscriber was located at the pier, while the second one were Thorben and Alexej cruising with MISSy about 100 to 200 m in front of the pier. We had quite good signal quality, even when operating in so-called full-duplex mode (both subsribers can talk simultaneously). Several people tested the phone - even very young ones, as you can see on the picture.
Thanks again to all people who helped us to let MISSy see finally the water (Matthias, Martin, Dietmar, Jan, and all the others).
Starting this winter term the DSS group offers a new lecture entiteled "Fundamentals of Acoustcs". The lecture is given by Dr. Jan Abshagen (see picture). It will be a 3+1 lecture which takes place once a week. The lecture will cover the following topics:
- fundamentals of vibrations,
- theory of sound fields,
- sound and systems,
- sound-structure interaction,
- ship acoustics,
- acoustic sensor systems,
- underwater noise measurement,
- impulsive underwater noise ,
- oceanographic instruments.
Further details can be found here.
On Friday, 29th of June, the Faculty of Engineering had the traditional summer event. During that event also the best finshing students of each study programme were honored.
Christin Bald who started last year her Ph.D. in our group was the best finishing student in the Master programme "Wirtschaftsingenieurwesen". Christin, congratulations from all of us.
Furthermore, Seedo Paul, who attended virtually all of the DSS lectures and did also his master thesis with us (anti-noise helmets for fire fighters), was honered as well. Seedo was the best "finisher" in the Master programme "Digital Communications". Seedo, also congratulations from the entire DSS team.
On July, 28th we had our next test with MISSy. This time our second approach of our steering concept as well as the GPS module in KiRAT were tested in terms of hard- and software. Furthermore, we decided to go to an (for us) unknown beach area and see if we were able to put MISSy quickly and savely into water.
The "water test" including the test of our trailor extenstion was very successful. Everythink works as expected. However, we still had some ideas for further improvements - as usual.
Also the GPS module works as expected. We guess that we had an average error of 1 to 3 m, which is o.k. for us. Special thanks to Frederik Kühne, who implemented the GPS module as part of his Bachelor thesis. However, while using the module some ideas for further improvments came up.
Our new steering concept works much better comparted to the previous one. However, since rather strong forces appeare when steering MISSy our gear transmission was not strong enough. Well, something to do for the next test. Anyhow, we had a lot of fun while performing this next MISSy test.
On Wednesday the 20th of June, several highschool students of the first senior classes of the Isarnwohld School Gettorf visited the DSS department. Therefore, Prof. Schmidt gave a talk about possible professions for electrical engineers (especially with focus on signal processing) at the Isarnwohld School two days before. So the highschool students could think about the addressed topics and are prepared for the applications shown on Wednesday. At the event on Wednesday first some students of the electrical engineering department talked about the experiences they made during studies and afterwards the doctoral candidates showed some of their work and some demos. We are pretty happy that the Isarnwohld School visited us today and we hoped that the highschool students and the teachers had also some fun visiting us! Special thanks to their very committed teacher, Jan Heidrich.
Prof. Anja Leue from the psychology department of our university organized a lecture series on the topic "language and society". Also the DSS group participated in that event and we presented some of our results on speech in disturbed environments. The lecture took place on Thursday, 5th of May, in one of the lecture rooms in the Audimax building. After the talk, a nice, interesting (and for our field) long discussion took place. Here is the contents of the DSS talk:
Nowadays technical systems allow for voice communication even in very disturbed environments. Examples are communication masks for firefighters, swim googles for under water speech communication or speech communication within cars. In the latter example, the speech of dialog partners is impaired by several factors. Depending on the driving speed, a moderate or even high level of background noise superposes to the speech signals generated by the passengers or by loudspeakers that emit the signals from communication partners connected via mobile phones. Due to the seat adjustment (position and orientation) the front passengers do not speak into the direction of the rear passengers and face-to-face communication among the passengers is not as easy as in a “normal” communication.
If so-called ICC systems (ICC abbreviates in-car communication) are used, the passengers are recorded using microphones. After appropriate signal processing (mainly noise, echo, and feedback reduction) the enhanced signals of the talkers are played back via loudspeakers close to the ears of the listening passengers. At first glance such systems face the same problems as hands-free or speech dialog systems but due to the closed electro-acoustic loop that they have to operate in special problems arise, e.g. correlation of the local signals with the loudspeaker signals that lead to problems when performing system identification with adaptive filters. Furthermore, the enhancement usually leads to a better signal-to-noise ratio at the ears of the listeners. However, the more the signal-to-noise ratio is improved for the listening passengers the more the speaking passengers are aware of or even disturbed by their own voices due to echo perception.
In this talk, I will try to mention most of the challenges that one faces when building enhancement systems for speech in disturbed environments. The solution to these challenges is usually a “cocktail” of individual processing units where the ingredients are low-delay filterbanks, adaptive structures for system identification, spectral suppression rules, decorrelation schemes, and adaptive mixing approaches. In most cases a compromise between the needs of the talking and the listening passengers has to be found which makes this application a very interesting challenge.
If one combines pure ICC systems with other speech and audio systems in a car such as hand-free, anti-noise, or music playback systems the complexity of the resulting system increases. However, the system components mentioned before can be combined such that they can overcome some of the problems, which is again an interesting challenge.
Let me finally mention that even after decades of great and continuous improvement in speech and audio signal processing the communication of people in highly disturbed environments could still be improved. Thus, speech signal enhancement remains “a rocky road” – to say it with the words of one of the early German speech processing researches.
Also in the week of DAGA but between the 21st to the 23rd March the Biosignals Workshop took place in the protestant monastery of St. Augustine in Erfurt. The topic was innovative processing of bioelectric and biomagnetic signals and was organized by the technical VDE committees „Biosignals“ and „Magnetic Methods in Medicine“. The DSS group (Christin and Eric) participated with two contributions in cooperation with the Physikalisch-Technische Bundesanstalt at the workshop. We would like to thank the committees and the organization team for the great workshop!
On 19th to 22nd March the 44th DAGA conference was held in Munich, Germany with about 1500 participants. The DSS group also participated with 9 contributions and the attendance at the conference.
On the occasion of 150 years TUM it was a double conference together with the GAMM Conference of the Society of Applied Math and Mechanic.
Topics like machine learning for speech diagnostics, evaluation of speech communication systems, detection and tracking for SONAR systems, underwater acoustics, anti-noise systems for firefighter helmets, speech perception using an ICC system, head-orientation estimation in motor vehicles and deep learning for bandwidth extension were presented and discussed.
We would like to thank the organizing teams for a great conference.
The 62th German Society for Clinical Neurophysiology and Functional Imaging (DGKN) conference was held in Berlin with about 1778 participants on 15th to 17nd March. Eric (DSS group) and Franziska Weitkamp (Department of Neurology, UKSH) also participated with one Poster and the attendance at the conference. We presented a new electrical approach to optimize the diagnostic specificity. We presented multichannel electric nerve conduction studies in combination with ultrasound, which resulted in a finer grained functional-spatial characterization of the nerve. We would like to thank Prof. Schulte-Mattler (Dept. of Neurology, University of Regensburg) for a great discussion regarding our CRC-Project and for all further support.
Beside the DGKN conference it was a very nice and enjoyable time with all other PhDs of the Department of Neurology. Special thanks to PD Dr. Helmut Laufs (Department of Neurology, UKSH) for organization of the complete trip.