Ivan Tashev
Principal Architect
Speech Technology Group

 Research interests

• Multichannel audio signals processing
• Algorithms for arrays of transducers (microphones, speakers, antennas)
• Processing of signals for enhancement, de-noising, de-reverberation, etc.
• Statistical processing of audio, biological, radio signals

 Background

Education

• Several short specializations in the area of eLearning in France (ENIC, ENSEA) and Italy (Bologna University) (1995-1996).
• Ph.D. in Computer Science, 1990, Technical University of Sofia, Bulgaria.
• Master's Degree in Electronics, 1984, Technical University of Sofia, Bulgaria.

Career

• Microsoft Corporation, Redmond, USA: various positions in COM+ and Application Center teams, 1998-2001. Joined Microsoft Research in 2001.
• Technical University of Sofia, Bulgaria: Assistant Professor, 1989-1998, Faculty of Electronic Engineering and Technology (lectures and labs for "Data and Signal Processing" and "Real time systems programming").
• Technical University of Sofia, Bulgaria: Researcher, 1986-1989, Research and Development Department
• Technical University of Sofia, Bulgaria: R&D engineer, 1984-1986, Research and Development Department

Resume

Click here

 Publications

More than 50 publications, 30 patents (issued and pending), one book and two book chapters. For the full list click here. 

Recent Publications

• Ivan Tashev, Jasha Droppo, Michael Seltzer, Alex Acero. “Robust Design of Wideband Loudspeaker Arrays”. International Conference on Audio, Speech and Signal Processing ICASSP 2008, Las Vegas, USA, April 2008. [PDF]
• Nilesh Madhu, Ivan Tashev, Alex Acero. “An EM-based Probabilistic Approach for Acoustic Echo Suppression”. International Conference on Audio, Speech and Signal Processing ICASSP 2008, Las Vegas, USA, April 2008. [PDF]
• Ivan Tashev, Michael L. Seltzer, Yun-Cheng Ju, Dong Yu, Alex Acero. "Commute UX: Telephone Dialog System for Location-based Services". Proceedings of SIGdial Workshop on Disclosure and Dialogue 2007, Antwerp, Belgium, September 2007. [PDF]
• Michael L. Seltzer, Yun-Cheng Ju, Ivan Tashev, Alex Acero. "Robust Location Understanding in Spoken Dialog Systems Using Intersections". Proceedings of Interspeech 2007, Antwerp, Belgium, August 2007. [PDF]
• Ivan Tashev, Henrique Malvar. “Stationary-tones Interference Cancellation Using Adaptive Tracking”. International Conference on Audio, Speech and Signal Processing ICASSP 2007, Honolulu, USA, April 2007. [PDF]
• Byung-Jun Yoon, Ivan Tashev, Alex Acero. “Robust Adaptive Beamforming Algorithm Using Instantaneous Direction of Arrival with Enhanced Noise Suppression Capability”. International Conference on Audio, Speech and Signal Processing ICASSP 2007, Honolulu, USA, April 2007. [PDF]
• Michael L. Seltzer, Ivan Tashev, Alex Acero. “Microphone Array Post-Filter Using Incremental Bayes Learning to Track the Spatial Distribution of Speech and Noise”. International Conference on Audio, Speech and Signal Processing ICASSP 2007, Honolulu, USA, April 2007. [PDF]
• Ivan Tashev, Alex Acero. Microphone Array Post-Processor Using Instantaneous Direction of Arrival. International Workshop on Acoustic, Echo and Noise Control IWAENC 2006, Paris, France, September 2006. [PDF]
• Yong Rui, Eric Rudolph, Li-wei He, Rico Malvar, Michael Cohen, Ivan Tashev. PING: A Group-to-Individual Distributed Meeting System. International Conference Multimedia and Expo ICME’06, Toronto, Ontario, Canada, July 2006. [PDF]
• Ivan Tashev, Jasha Droppo, Alex Acero. Suppression Rule for Speech Recognition Friendly Noise Suppressors. Eight International Conference Digital Signal Processing and Applications DSPA’06, Moscow, Russia, March 2006. [PDF]
• Zicheng Liu, Michael Seltzer, Alex Acero, Ivan Tashev, Zhengyou Zhang, Mike Sinclair. "A Compact Multi-Sensor Headset for Hands-Free Communication". Workshop on Applications of Signal Processing to Audio and Acoustics, New Paltz, NY, USA, October 2005. [PDF]
• Ivan Tashev. "Beamformer Sensitivity to Microphone Manufacturing Tolerances". Nineteenth International Conference Systems for Automation of Engineering and Research SAER 2005, St. Konstantin Resort, Bulgaria, September 2005. [PDF]
• Ivan Tashev, Michael Seltzer, Alex Acero. "Microphone Array for Headset with Spatial Noise Suppressor". Proceedings of Ninth International Workshop on Acoustic, Echo and Noise Control IWAENC 2005, Eindhoven, The Netherlands, September 2005. [PDF]
• Ivan Tashev, Henrique S. Malvar. "A new beamformer design algorithm for microphone arrays". Proceedings of International Conference of Acoustic, Speech and Signal Processing ICASSP 2005, Philadelphia, PA, USA, March 2005. [PDF]
• Ivan Tashev, Daniel Allred. "Reverberation reduction for improved speech recognition". Proceedings of Hands-Free Communication and Microphone Arrays, Piscataway, NJ, USA, March 2005. [PDF]
• Ivan Tashev. "Gain Self-Calibration Procedure for Microphone Arrays". Proceedings of International Conference for Multimedia and Expo ICME 2004, Taipei, Taiwan, June 2004. [PDF]
• Ivan Tashev. "Improving Meetings with Microphone Array Algorithms". Machine Learning Meets the User Interface Workshop, Neural Information Processing Systems NIPS 2003, Whistler, Canada, December 2003. [PDF]
• Ross Cutler, Yong Rui, Anoop Gupta, JJ Cadiz, Ivan Tashev, Li-wei He, Alex Colburn, Zhengyou Zhang, Zicheng Liu, Steve Silverberg. “Distributed Meetings: A Meeting Capture and Broadcasting System”. Proceedings of ACM Multimedia 2002, Nice, France, December 2002. [PDF]
   

Selected Presentations

• "Commute UX: Telephone Dialog System for Location-based Services". Presentation during SIGdial Workshop on Disclosure and Dialogue 2007, Antwerp, Belgium, September 2007. [PDF]
• "Defeating Ambient Noise: Practical Approaches for Noise Reduction and Suppression". Tutorial during IEEE International Conference of Acoustic, Speech and Signal Processing ICASSP 2006, Toulouse, France, May 2006. [Slides, References]
• "Microphone Array for Headset with Spatial Noise Suppressor". Presentation during Ninth International Workshop on Acoustic, Echo and Noise Control IWAENC 2005, Eindhoven, The Netherlands, September 2005. [PDF]
• "Microphone Array Support in Windows Longhorn". Presentation during Windows Hardware Experience Conference WinHEC 2005, Seattle, USA, May 2005. The same talk given during WinHEC 2005, Taipei, Taiwan, June 2005. [PDF]
• "Microphone Array Project in Microsoft Research: Approach and Results". Presentation in National Taiwan University and Academia Sinica, July 2004, Taipei, Taiwan. [PDF]
• "Improving Meetings with Microphone Array Algorithms". Presentation during Machine Learning Meets the User Interface Workshop, Neural Information Processing Systems NIPS 2003, Whistler, Canada, December 2003. [PDF]
• "Application Center 2000 Interoperability and Reliability". Presentation during Application Center 2000 Airlift, Redmond, USA, May 2001. [PDF]

 Professional Activities

Senior Member of IEEE and member of AES. Served as member of the Technical Program Committee of ICME 2002 and ICME 2003, session chair in ICME 2003. Co-founder in 1986 and organizational secretary for 12 years of the International Conference Systems for Automation of Engineering and Research (SAER), now serving as member of the International Organizing Committee. Member of the TC of International Workshop on Acoustics, Echo and Noise Control (IWAENC) since 2006. Member of the TC of Workshop on Applications of Signal Processing to Audio and Acoustics (WASPAA) since 2006.

 Projects

Here are some of the projects I enjoyed during my career in no particular order. 

  Microphone Array Project

Providing a hands free sound capture in modern computers for the needs of real-time communication and speech recognition (voice commands and dictation) is a technologically difficult and challenging task. Designing a real-time microphone array processing algorithm for optimal noise suppression, besides being a interesting research problem, provides additional challenges when the time comes for productizing of the software and hardware. After building the first prototypes of USB linear four element array for office use and circular eight element array for the center of the conference room table started the difficult transition from "microphone array algorithms" to "algorithms for manufactureable microphone arrays". The whole process includes working with product teams inside Microsoft and evangelization of this technology to laptop, tablet and computer monitor manufacturers outside Microsoft by publishing white papers and giving talks. The project is in very advanced phase for shipping as integrated in Windows Vista microphone array support. Article about the project is posted here, a video containing interview with Rico Malvar talking about the project can be found here. More details can be found on the Microphone Array Project web page.

  Control system for Universal Laser Ranging System ULIS-630

In the pre-GPS era the way to measure precisely the geographical coordinates of given point was by watching satellites and measure the distance to them using laser ranging systems. Universal Laser Ranging System ULIS-630 was a large international project with participation of research and academic organizations from Eastern Europe (Academy of Sciences of the ex-Soviet Union in Moscow, Lithuanian Technical University in Riga, Bulgarian Academy of Sciences in Sofia, Moscow Electro-technical Institute, Technical University of Sofia, others). The optical system is with so called horizontal mount and consists of two paired telescopes: transmitting (Galileo type, focal length of 12 meters, green laser with 1 J energy of the 1ns long pulse) and receiving (Cassegrain type, 630 mm main mirror diameter, 11.5 meters focal length and photo-multiplier tube as receiver). It is controlled by a distributed computer system for tracking the visible trajectory of the satellite, firing the laser, collecting and processing the results. My work here become the core of my Ph.D. thesis. The system itself, besides everything else, offered decent view of planets and celestial objects (see picture of Jupiter here)

  Application Center 2000 Pre-Flight Checks

Microsoft Application Center is a web and component clusters management software. Targeting middle range web sites it offers set of innovative features. The "Application Center 2000 Pre-Flight Checks" was designed to improve out-of-the-box experience of the IT personnel, but become the unofficial tutorial of the product. I enjoyed finding the easiest way to demonstrate the product features with minimum additional software. Parts of this document were used in the Application Center Resource Kit. 

  Distributed Meetings System

This was my first project in Microsoft Research. It was a big, complex system for meetings capture and recording. The capturing devices were 360 degrees RingCam, eight element circular microphone array, overview camera, whiteboard camera, etc. The project combined technologies, designed in the Collaboration, Communication and Multimedia Team and included deployment of ten of these systems in various conference rooms in Microsoft to study the users behavior and to get some feedback. See our ACM paper for more details.

  Dereverberation Project

The project started with simple goal to reduce the word error rate for speech recognition purposes for distances of up to 1.5 meters. This was the summer project of my intern Daniel Allred, Ph.D. student in GeorgiaTech. During his the second internship in Microsoft Research the project was extended and re-scoped to cover some perceptual scenarios as well.  More details can be found on Dereverberation Project web page.

  Speaker Array Project

This is pure research project for now. With my colleagues Jasha Droppo and Mike Seltzer, we decided to see what can be reused from our experience in beamforming design for microphone arrays. The loudspeaker array consists of sixteen inexpensive speakers and has linear geometry. The project was demonstrated during Microsoft Research TechFest 2007 as "Personal Audio Space" and definitely had the "Wow!" effect among the visitors in our booth. We demonstrated focusing the sound in given area and dual beam mode when you hear one music channel in one place and a second music channel in another. The attending journalists liked the demo and it was widely published in the press: WIRED Blog Network, Seattle PI, MIT Technology Review, MSR web site, many others, in different languages and from different countries. Currently we are exploring various scenarios and potential applications for this technology.

E-mail: ivantash--at--microsoft--dot--com
Postal Mail: Microsoft Corporation, One Microsoft Way, Redmond WA, 98052-6399, USA
Tel: (425) 706-1667
Fax: (425) 936-7329 (This is the main MS FAX number so make sure to send documents to my attention)