A significant part of my career so far (Master's, Ph.D. and Post-Doc) was focussed on
acoustics and Bayesian methods (sequential Monte Carlo), with significant research work carried
out on various aspects of microphone array processing, acoustic beamforming, and acoustic
source localisation and tracking.
This simple web site aims to provide some basic information about who I
am and what I do. Please feel free to contact me directly if you would
like more specific information about me or my work.
Thanks for visiting! I hope you find these few pages interesting and useful...
On this web page...
Here is a summary of the information that you will find further below on this web page:
I was born in
Porrentruy, Jura, Switzerland, and
spent the first 20 to 25 years of my life around that place doing all
sorts of stuff.
Then in 1999, after finishing my undergraduate studies at the ETHZ in Zurich, I challenged
myself to go and study overseas for a while. That turned out to work pretty
well as I spent about 5 years at the ANU in Canberra, followed by a 3 year postdoc
with WATRI in Perth, Australia, and I am now
holding a permanent position of Research Scientist with CSIRO, also
in Western Australia. On March 23, 2009, I also officially became a citizen of Australia.
The best way to describe myself is probably as a chronic
perfectionist who enjoys cooking, playing pool (billiards), swimming,
horse riding, and playing guitar and didgeridoo, among lots of other things. One way or
another, I also grew up to become a fanatical addict of LaTeX, Linux,
and the Calvin & Hobbes comic strips.
Short bio:if you prefer something more
formal...
Eric Lehmann graduated
in 1999 from the Swiss Federal Institute of Technology in Zurich (ETHZ),
Switzerland, with a Diploma in Electrical Engineering (Master equivalent).
He received the M.Phil. and Ph.D. degrees, both in Electrical Engineering,
from the Australian National University (Canberra) in 2000 and 2004 respectively.
Between 2004 and 2008, he held various research positions with National ICT Australia (NICTA) in
Canberra, ACT, as well as the Western Australian
Telecommunications Research Institute (WATRI) in Perth, WA. He is now working
as a Research Scientist for the Commonwealth Scientific and Industrial Research Organisation (CSIRO)
in Perth, within the division of Mathematics, Informatics and Statistics.
His current scientific interests include various aspects of signal processing (including acoustics,
remote sensing, speech, array and image processing), statistical methods for data integration,
as well as Bayesian estimation and tracking (with particular emphasis on the application of
sequential Monte Carlo methods, i.e., particle filters).
Curriculum:
here are links to my Curriculum Vitæ (version May 2011): full-blown version. Or simply
see below for online information...
Ph.D. in Engineering, Research School
of Information Sciences and Engineering, the Australian National
University, Canberra, Australia
Topic: "Particle Filtering Methods
for Acoustic Source Localisation and Tracking"
1999
- 2000
M.Phil. in Engineering, Faculty of
Engineering and Information Technology, The Australian National
University, Canberra, Australia
Topic: "Real-Time Implementation of
a Nearfield Broadband Acoustic Beamformer"
Undergraduate
1994
- 1999
Dipl. El.-Ing. ETH (electrical
engineering), Department of Electrical Engineering, Swiss Federal
Institute of Technology, Zurich, Switzerland (ETHZ)
Specialisation in Signal
Processing. Diploma work: "Implementation of Control Algorithms for a Satellite Laser
Pointing Mechanism"
Work
experience
2008
- present
Research Scientist with the Commonwealth Scientific
and Industrial Research Organisation (CSIRO), within the division of Mathematics, Informatics
and Statistics in Floreat, Western Australia. This position currently involves the
use of image processing techniques for remote sensing data such as airborne and
satellite imagery, as well as synthetic aperture radar (SAR). The focus is on the
multi-sensor integration and analysis of spatial and temporal data in order to provide accurate
information on environmental factors such as vegetation cover and land use, as well
as their changes over time. These projects are carried out in collaboration with
various industrial and governmental organisations in Australia and overseas.
Main research activities (current and past) include:
Radar remote sensing: data fusion of synthetic aperture radar (SAR) data with optical
Landsat imagery for forest mapping and monitoring (part of the GEO Forest Carbon Task)
Model—data fusion techniques: data assimilation of soil moisture observations (remote sensing)
with model estimates for water resources assessment across Australia (part of the WIRADA partnership between
CSIRO and Australia's Bureau of Meteorology, see more info
here)
Vegetation trends product: derivation and computation of vegetation trends across Australia since 1972
(part of Australia's National
Carbon Accounting System, NCAS)
Sparse vegetation monitoring: classification of sparsely vegetated zones (5-20% canopy cover) across
Australia since 1989 (part of NCAS)
Seabed mapping: development of spatial tools for mapping coastal seabed condition using acoustic swath
data (multi-beam echosounder) and video data
2005
- 2008
Research Fellow within the Signal Processing
Laboratory at the Western Australian Telecommunications Research Institute (WATRI),
Perth, Australia. My research at WATRI dealt with various aspects of array
signal processing, acoustic speaker tracking and speech enhancement. An example of the
type of research I was working on can be found here.
As part of my work at WATRI, I was involved in the LaMP research project
carried out in collaboration with, and partly funded by NICTA.
Main research activities include:
Source tracking: acoustic speaker localisation and tracking by means of array signal processing
and sequential Monte Carlo (SMC) methods
Voice activity detection: integration of VAD data into SMC algorithm for acoustic speaker tracking
Dynamics tracking: optimisation of dynamics models for speaker tracking using SMC and evolutionary
algorithms
Room acoustics: reverberation modelling for the simulation of room impulse responses
Other research: speech onset detection for improved time-delay estimation; minimum statistics (noise
tracking) for voice activity detection; circular array processing for angle-of-arrival speaker tracking;
joint audio-video speaker tracking
2004
(3 months)
Research Engineer with National ICT
Australia Ltd (NICTA). This work involved the implementation of a real-time
algorithm for localising and tracking an acoustic source in reverberant
environments, using an array of microphones. This algorithm was based
on a particle filtering method using importance sampling, developed
during my previous Ph.D. research. Some demonstration results from
this application can be found here.
Other achievements
Member of the Technical Program Committee for
WASPAA 2011
Member of the Technical Program Committee for
WASPAA 2009
Member of the Technical Program Committee for
WASPAA
2007
Paper reviewer for various conferences/workshops and scientific journals, including:
My Ph.D. research
project focused on the study of sequential Monte Carlo
methods as a new tool for carrying out various signal processing
tasks. More specifically, I was working on the problem of acoustic
source localisation and tracking in reverberant environments, using
array signal processing principles. In this specific case, particle
filters offer an efficient way of dealing with the complex problem of
reverberation. The project involved primarily the development and test
of several particle filter algorithms using recordings of real audio
data.
As a major result of this research, a particle filter using the
principle of importance sampling was designed and successfully tested.
This algorithm allows the automatic detection of new speakers entering
the acoustic scene and also automatically recovers following the
occurrence a track loss (for instance as a result of a pause in the
speech signal). This specific particle filter was also implemented in
real-time on a standard Linux-based desktop computer and tested in a
typical office room equipped with a 16 sensor array. Some tracking
examples from this algorithm have been recorded (originally running in
real-time) and can be found for demonstration purposes here.
My Ph.D. led me to
focus principally on Bayesian estimation and Sequential Monte Carlo
methods, acoustic source localisation and tracking, and array signal
processing. More generally however, my main research interests also
include (in random order):
acoustics
digital signal processing
speech processing and enhancement
algorithms for real-time audio processing
multimedia information processing and human-machine interaction
I also highly enjoy any kind of software programming and GUI development
in general (Assembler, Matlab, C, etc.).
Notes:
In the lists below, publications listed in green
are the result of my work with the CSIRO division of Mathematics, Informatics and Statistics.
[...]*: publications flagged with an asterisk indicate presentations at conferences/workshops that
did not result in a full paper (usually based on an extended abstract only).
Theses
[T2]
"Particle Filtering Methods for Acoustic
Source Localisation and Tracking", Ph.D. Thesis (Engineering), ANU,
July 2004.
[PDF (4.2MB), gzipped postscript (2.1MB), BibTeX+Abstract] Cross-ref.: see also [J1],
[J2], [C1], [N1] and [R1] for related and/or updated contents.
[T1]
"Real-Time Implementation of a Nearfield
Broadband Acoustic Beamformer", M.Phil. Engineering Thesis, ANU, November
2000.
[PDF (2MB), gzipped postscript (2.2MB), BibTeX+Abstract]
Journal papers (peer-reviewed)
[J7]
Eric A. Lehmann, Peter A. Caccetta, Zheng-Shu Zhou, Stephen J. McNeill, Xiaoliang Wu
and Anthea L. Mitchell, Joint processing of Landsat and
ALOS-PALSAR data for forest mapping and monitoring, IEEE Transactions on Geoscience
and Remote Sensing, vol. 50, nr. 1, pp. 55-67, January 2012.
[PDF Preprint (1.2MB), BibTeX+Abstract, published
paper]
[J6]
Eric A. Lehmann and Anders M. Johansson, Diffuse
Reverberation Model for Efficient Image-Source Simulation of Room Impulse
Responses, IEEE Transactions on Audio, Speech and Language Processing,
vol. 18, no. 6, pp. 1429-1439, August 2010.
[PDF Preprint (340kB), BibTeX+Abstract, supplementary material, published
paper]
[J5]
Anders M. Johansson and Eric A. Lehmann,
Evolutionary Optimization of Dynamics Models
in Sequential Monte Carlo Target Tracking, IEEE Transactions
on Evolutionary Computation, vol. 13, no. 4, pp. 879-894, August 2009.
[PDF Preprint (715kB), BibTeX+Abstract, published
paper]
[J4]
Eric A. Lehmann and Anders M. Johansson,
Prediction of Energy Decay in Room Impulse
Responses Simulated with an Image-Source Model, Journal of the Acoustical
Society of America, vol. 124, nr. 1, pp. 269-277, July 2008.
[PDF Preprint (450kB), BibTeX+Abstract, supplementary material, published
paper] Cross-ref.: see also [C7] and
[R4] for related work.
[J3]
Eric A. Lehmann and Anders M. Johansson,
Particle Filter with Integrated Voice
Activity Detection for Acoustic Source Tracking, EURASIP
Journal on Advances in Signal Processing, vol. 2007, Article ID 50870, 11 pages,
2007.
[PDF Preprint (270kB), BibTeX+Abstract, published
paper] Cross-ref.: see also [C3],
[C4] and [R2] for related work.
[J2]
Eric A. Lehmann and Robert C. Williamson,
Particle Filter Design using Importance
Sampling for Acoustic Source Localisation and Tracking in Reverberant
Environments, EURASIP Journal on Applied Signal Processing, special
issue on Advances in Multi-Microphone Speech Processing, vol. 2006, Article
ID 17021, 9 pages, 2006.
[PDF Preprint (330kB), BibTeX+Abstract, supplementary material, published
paper] Cross-ref.: see also [N1]
for related work.
[J1]
Darren B. Ward, Eric A. Lehmann, and
Robert C. Williamson, Particle Filtering
Algorithms for Tracking an Acoustic Source in a Reverberant Environment,
IEEE Transactions on Speech and Audio Processing, vol. 11, nr. 6, pp. 826-836,
November 2003.
[PDF Preprint (500kB), BibTeX+Abstract, published
paper] Cross-ref.: see also [C1]
for related work.
Conference and workshop papers (peer-reviewed)
[C10]
G. Chiu and E. Lehmann, Bayesian hierarchical modelling: incorporating
spatial information in water resources assessment and accounting, International Congress on Modelling
and Simulation (MODSIM'2011), pp. 3349-3355, Perth, Australia, December 2011.
[published paper, appendix]
[C9]
B. Henderson, L. Renzullo, A. Van Dijk, G. Chiu, W. Jin, E. Lehmann, S. Barry, and A. Frost,
Balancing models and data: Model data fusion for improved continental
water resource assessment, WIRADA Science Symposium, Melbourne, Australia, August 2011.
[C8]
E. Lehmann, Z.-S. Zhou, P. Caccetta, A. Mitchell, A. Milne, K. Lowell and S. McNeill, Combined Analysis of Optical and SAR Remote Sensing Data for Forest Mapping and
Monitoring, International Symposium on Digital Earth (ISDE7), Perth, Australia, August 2011.
[PDF Preprint (1.8MB), BibTeX+Abstract, published
paper]
[C7]
Eric A. Lehmann, Anders M. Johansson, and Sven Nordholm, Reverberation-Time Prediction Method for Room Impulse Responses Simulated with
the Image-Source Model, Proceedings of the IEEE Workshop on Applications of Signal
Processing to Audio and Acoustics (WASPAA'07), pp. 159-162, New Paltz, NY, USA, October 2007.
[PDF Preprint (148kB), Revised PDF (150kB), BibTeX+Abstract, supplementary material, published
paper] Note: the revised version of
this paper contains a number of minor corrections made to the paper after its publication in WASPAA. Cross-ref.: see also [J4] and
[R4] for related work.
[C6]
Eric A. Lehmann, Anders M. Johansson, and Sven Nordholm,
Modeling of Motion Dynamics and its Influence
on the Performance of a Particle Filter for Acoustic Speaker Tracking,
Proceedings of the IEEE Workshop on Applications of Signal Processing to Audio and
Acoustics (WASPAA'07), pp. 98-101, New Paltz, NY, USA, October 2007.
[PDF Preprint (235kB), BibTeX+Abstract, published
paper] Cross-ref.: see also [R3] for related work.
[C5]
Thorsten Kühnapfel, Tele Tan, Svetha Venkatesh, and Eric Lehmann,
Calibration of Audio-Video Sensors for Multi-Modal
Event Indexing, Proceedings of the IEEE International Conference on Acoustics, Speech
and Signal Processing (ICASSP'07), vol. 2, pp. 741-744, Honolulu, HI, USA, April 2007.
[PDF Preprint (375kB), BibTeX+Abstract, published
paper]
[C4]
Anders M. Johansson, Eric A. Lehmann, and Sven Nordholm,
Real-time Implementation of a Particle Filter
with Integrated Voice Activity Detector for Acoustic Speaker Tracking,
Proceedings of the IEEE Asia Pacific Conference on Circuits and Systems (APCCAS'06),
pp. 1004-1007, Singapore, December 2006.
[PDF Preprint (127kB), BibTeX+Abstract, supplementary material, published
paper] Cross-ref.: see also [J3], [C3],
and [R2] for related work.
[C3]
Eric A. Lehmann and Anders M. Johansson,
Experimental Performance Assessment of a
Particle Filter with Voice Activity Data Fusion for Acoustic Speaker
Tracking, Proceedings of the IEEE Nordic Signal Processing
Symposium (NORSIG'06), pp. 126-129, Reykjavik, Iceland, June 2006.
[PDF Preprint (154kB), BibTeX+Abstract, published
paper] Cross-ref.: see also [J3],
[C4] and [R2] for related work.
[C2]
Eric A. Lehmann, Particle Filtering Approach to Adaptive Time-Delay Estimation,
Proceedings of the IEEE International Conference on Acoustics, Speech, and Signal
Processing (ICASSP'06), vol. 4, pp. 1129-1132, Toulouse, France, May 2006.
[PDF Preprint (110kB), BibTeX+Abstract, published
paper]
[C1]
Eric A. Lehmann, Darren B. Ward, and Robert
C. Williamson, Experimental Comparison of
Particle Filtering Algorithms for Acoustic Source Localization in a Reverberant
Room, Proceedings of the IEEE International Conference on Acoustics,
Speech, and Signal Processing (ICASSP'03), vol. 5, pp. 177-180, Hong Kong,
China, April 2003.
[PDF Preprint (140kB), BibTeX+Abstract, published
paper] Note: due to the cancelation of
ICASSP'03 following the SARS epidemic, this paper was presented at the IEEE
Workshop on Applications of Signal Processing to Audio and Acoustics (WASPAA'03),
New Paltz, New York, October 2003. Cross-ref.: see also [J1]
for related work.
Non-refereed conference/workshop papers
[N17]*
G. Chiu and E. Lehmann, Bayesian hierarchical modelling: incorporating
spatial information in the AWRA inference framework, The International Environmetrics Society (TIES) Conference,
Hyderabad, India, January 2012.
[N16]*
G. Chiu and E. Lehmann, Making use of multiple soil moisture
products through spatial modelling, The International Environmetrics Society (TIES) Conference,
Hyderabad, India, January 2012.
[N15]*
T. Milne, A. Mitchell, I. Tapley, K. Lowell, P. Caccetta, E. Lehmann and Z.-S. Zhou,
Assessment of forest information derived from the interoperability of
radar and optical data, International Asia-Pacific Conference on Synthetic Aperture Radar (APSAR),
Seoul, South Korea, September 2011.
[N14]*
A. Mitchell, A. Milne, I. Tapley, K. Lowell, E. Lehmann, Z.-S. Zhou and P. Caccetta,
Forest information monitoring in Tasmania using synthetic aperture
radar data, International Symposium on Digital Earth (ISDE7), Perth, Australia, August 2011.
[N13]*
G. Chiu and E. Lehmann, Bayesian hierarchical modelling: incorporating
spatial information in the AWRA framework, WIRADA Science Symposium, Melbourne, Australia, August
2011.
[N12]
Z.-S. Zhou, P. Caccetta, E. Lehmann, S. McNeill, A. Mitchell, A. Milne, I. Tapley and K. Lowell,
Dual Polarised Entropy/Alpha Decomposition and Coherence
Optimisation for Improved Forest Biomass Mapping, IEEE International Geoscience and
Remote Sensing Symposium (IGARSS 2011), pp. 3951-3954 , Vancouver, Canada, July 2011.
[published paper]
[N11]
A. L. Mitchell, T. Milne, I. Tapley, K. Lowell, P. Caccetta, E. Lehmann, Z.-S. Zhou and A. Held,
Interoperability of Radar and Optical Data for Forest
Information Assessment, IEEE International Geoscience and Remote Sensing Symposium
(IGARSS 2011), pp. 1397-1400, Vancouver, Canada, July 2011.
[published paper]
[N10]
E. Lehmann, P. Caccetta, Z.-S. Zhou, A. Mitchell, I. Tapley, A. Milne, A. Held, K.
Lowell, and S. McNeill, Forest Discrimination Analysis
of Combined Landsat and ALOS-PALSAR Data, 34th International Symposium on
Remote Sensing of Environment (ISRSE 2011), Sydney, Australia, April 2011.
[PDF Preprint (1.8MB), BibTeX+Abstract, published paper]
[N9]
Z.-S. Zhou, E. Lehmann, X. Wu, P. Caccetta, S. McNeill, A. Mitchell, A. Milne, I.
Tapley, and K. Lowell, Terrain Slope Correction and
Precise Registration of SAR Data for Forest Mapping and Monitoring, 34th
International Symposium on Remote Sensing of Environment (ISRSE 2011), Sydney, Australia,
April 2011.
[published paper]
[N8]
A. L. Mitchell, A. Milne, I. Tapley, K. Lowell, P. Caccetta, E. Lehmann, Z.-S. Zhou,
and A. Held, Key Outcomes of the Tasmania 'National
Demonstrator': A Project for the GEO Forest Carbon Tracking Task, 34th
International Symposium on Remote Sensing of Environment (ISRSE 2011), Sydney, Australia,
April 2011.
[published paper]
[N7]
K. Lowell, A. Mitchell, I. Tapley, A. Milne, E. Lehmann, Z.-S. Zhou, P. Cacetta,
and A. Held, Evaluating and Characterising Image
Classification Interoperability, 34th International Symposium on Remote
Sensing of Environment (ISRSE 2011), Sydney, Australia, April 2011.
[published paper]
[N6]
Anthea L. Mitchell, Tony Milne, Ian Tapley, Kim Lowell, Peter Caccetta, Eric Lehmann, and
Zheng-Shu Zhou, Wall-to-Wall Mapping of Forest Extent
and Change in Tasmania using ALOS Palsar Data,
IEEE International Geoscience and Remote Sensing Symposium (IGARSS 2010), pp. 1230-1233, Honolulu, Hawaii,
July 2010.
[published paper]
[N5]*
Anthea L. Mitchell, Tony Milne, Ian Tapley, Kim Lowell, Peter Caccetta, Eric Lehmann,
Zheng-Shu Zhou, and Alex Held, Mapping of Forest Extent
and Change in Tasmania using ALOS Palsar Data in Support of the GEO Forest Carbon Tracking,
European Space Agency Living Planet Symposium, Bergen, Norway, June-July 2010.
[N4]
Zheng-Shu Zhou, Eric Lehmann, Peter Caccetta, and Stephen McNeill, Use of ALOS-PALSAR Data Associated with Landsat Imagery for Precise Forest Mapping:
Tasmanian Pilot, European Conference on Synthetic Aperture Radar (EUSAR 2010),
pp. 98-101, Aachen, Germany, June 2010.
[published paper]
[N3]*
Z.-S. Zhou, E. A. Lehmann, P. A. Caccetta, A. L. Mitchell, T. Milne, and I. Tapley,
Experiments in Radar-Optical Forest Monitoring:
Tasmanian Pilot, Workshop on Progress in Radar Research (PIRR 2010),
Adelaide, Australia, April 2010.
[N2]
Suzanne L. Furby, Peter A. Caccetta, Jeremy F. Wallace, Eric A. Lehmann, and Katherine
Zdunic, Recent Development in Vegetation Monitoring
Products from Australia’s National Carbon Accounting System, Proceedings of the
IEEE International Geoscience & Remote Sensing Symposium (IGARSS 2009), vol. IV, pp. 276-279, Cape Town, South
Africa, July 2009.
[published paper]
[N1]*
Eric A. Lehmann and Robert C. Williamson,
Importance Sampling Particle Filter for
Robust Acoustic Source Localisation and Tracking in Reverberant
Environments, Joint Workshop on Hands-Free Speech
Communication and Microphone Arrays (HSCMA'05), Rutgers University,
Piscataway, New Jersey, USA, March 17-18 2005.
[PDF Preprint (120kB), BibTeX] Cross-ref.: see also [J2]
for related work.
Technical and client reports (internally reviewed)
[R8]
R. Lagerstrom, M. Berman, G. Stone, A. Traylen and E. Lehmann, Unmixing
a time series of Landsat Thematic Mapper images of Tasmania, CSIRO Technical Report EP114256, June 2011.
[R7]
B. Henderson, G. Chiu, W. Jin, E. Lehmann, and S. Barry, AWRA
model-data fusion: Evaluation, error characterisation and blending, Client Report, CSIRO
Water for a Healthy Country Flagship, 2011.
[R6]
B. Henderson, L. Renzullo, A. van Dijk, S. Barry, G. Chiu, B. Gouweleeuw, W. Jin, E. Lehmann, J. Lerat,
Z. Paydar, M. Stenson, Road map for AWRA-L model-data fusion,
Client Report, CSIRO Water for a Health Country Flagship, 2011.
[R5]
S. L. Furby, K. Zdunic, and E. Lehmann, Monitoring Woody
Vegetation Trends: NCAS Trends Product Version 1.0, CSIRO MIS Technical Report 2008/140,
2008.
[R4]
Eric A. Lehmann and Anders M. Johansson, Prediction of Energy
Decay in Room Impulse Responses Simulated with the Image Source Model, NICTA/WATRI
Technical Report PRJ-NICTA-PM-025, Western Australian Telecommunications Research Institute,
Perth, Australia, June 2008.
[PDF (750kB), BibTeX+Abstract, supplementary material] Cross-ref.: this work was published in [C7] and [J4].
[R3]
Eric A. Lehmann and Anders M. Johansson, Dynamics Models
for Acoustic Speaker Tracking—Preliminary Results, NICTA/WATRI Technical Report PRJ-NICTA-PM-023,
Western Australian Telecommunications Research Institute, Perth, Australia, August 2007.
[PDF (510kB), BibTeX+Abstract] Cross-ref.: this work was published in [C6].
[R2]
Eric A. Lehmann and Anders M. Johansson, Particle
Filter with Integrated Voice Activity Detection for Acoustic Source Tracking,
NICTA/WATRI Technical Report PRJ-NICTA-PM-008, Western Australian Telecommunications
Research Institute, Perth, Australia, December 2006.
[PDF (550kB), BibTeX+Abstract] Cross-ref.: this work was published in
[J3], [C3] and [C4].
[R1]
Eric A. Lehmann and Robert C. Williamson, Posterior
Cramér-Rao Bound for Acoustic Source Tracking in Reverberant Environments, NICTA
Technical Report ISSN 1833-9646, National ICT Australia, Canberra, Australia, December 2006.
[PDF (390kB), BibTeX+Abstract]
Eric A.
Lehmann
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