CMSC828D : Algorithms and systems for capture and playback of spatial audio.
Time: MW from 3:30-4:45; Spring 2006.
Instructor:
Prerequisites: The course will be somewhat mathematical, and you should be comfortable or willing to work with some differential equations and do some (Matlab) programming.
Exams: There will be a mid-term and a final exam. In addition there will be homework that either involves short problem sets, or require reading of research papers.
Credit: For computer science students, the class will count as a PhD qualifying course, and a MS qualifying course in Visual and Geometric Computing. The MS comp grades will be based on the mid-term and final exam.
Short outline:
Audio is a fundamental mode of human perception, and becoming increasingly important in machine perception. The principles of the way humans perceive their space via audition are beginning to be understood. Similarly, machine systems that track and locate objects via the sound they emanate are becoming practical and widely deployed. This course will serve as a broad introduction to graduate work in the field.
The course will survey the field of audio capture, processing and playback. A series of introductory lectures by the instructor will provide the physical, mathematical and signal processing basis for the course. The course will then move on to a discussion of papers and systems dealing with various aspects of spatial audio.
Detailed outline:
A survey of the field and applications;
Some basic principles of physical acoustics;
Partial differential equations governing acoustic wave propagation
Notions of frequency and the Fourier transform;
An introduction to the human auditory system
An introduction to signal processing
Source localization and beamforming with arrays of microphones.
Human spatial hearing: The physical and psychoacoustical basis of sound localization and space perception.
Room acoustics: sound propagation in rooms. Modeling. The influence of short and long term reverberation.
Head related transfer functions
Modeling Room impulse responses and head related impulse responses.
An introduction to commercial systems for surround sound and spatial audio.
Emerging Spatial Audio Playback systems: Wave Field Synthesis. Ambisonics.
Research systems being developed at the
Selected Research topics
Policy: Honor code http://www.studenthonorcouncil.umd.edu/code.html
Grading: Homework 40%, Mid-Term 25%, Final 35%
DATE |
LECTURE |
CONTENTS |
01/25/2006 |
Introduction to the course and audio in computing |
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01/30/2006 |
Physical Acoustics |
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02/01/2006 |
The wave equation. Helmholtz equation. Boundary Conditions. Properties of solutions. |
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02/06/2006 |
(Guest lecture by Dr. Elena Grassi). Using Matlab to do digital audio Analog_in.m makesignal.m Analog_out.m filters.m Fig1.m Figure2.m |
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02/08/2006 |
Separation of Variables. Fourier Series. |
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02/13/2006 |
FFT Homework Problems 1, 2, 8 |
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02/15/2006 |
Introduction to Signal Processing (based on material from CERN) |
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02/20/2006 |
Convolution, Impulse Response (based on Berkeley EE course) |
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02/22/2006 |
Fourier analysis by the auditory system http://www.doc.ic.ac.uk/~phwl/teaching/mm/cochleaWeb3.mov Homework question: Plot spectrograms of different sounds (“words”) |
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02/27/2006 |
Dimensions of “auditory” space. Capacity of humans to detect
intensity, pitch, location. Based on a tutorial lecture by Prof. Simon Carlile of |
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03/01/2006 |
Lecture 11 |
A continuation of material in lecture 10. Microphone arrays: Reading material Chapter 1 and 2 of Michael Brandstein’s Ph.D. thesis (1995). |
03/06/2006 |
Time delay estimation |
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03/08/2006 |
Beamforming |
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03/13/2006 |
Spherical arrays |
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03/15/2006 |
Lecture 15 (see previous class notes) |
Spherical arrays |
03/20/2006 |
No class |
Spring break |
03/27/2006 |
Head Related Transfer functions Papers: Spherical Model: Duda and Martens, 1998, Head and Torso Models: Algazi et al. 2002, |
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03/29/2006 |
Lecture 17 (see previous class notes) |
Recreation of Spatial Audio: Zotkin et al. 2004, The CIPIC HRTF Database: Algazi et al. 2001 Homework 4 Allen and Berkley, 1979 Dmitry’s Snowman HRTF code shrtf.c |
04/03/2006 |
Plane-wave representation HRTF and spherical array based playback |
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04/05/2005 |
Transaural rendering Commercial speaker-based spatial audio systems |
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04/10/2006 |
Room Acoustics |
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04/12/2006 |
Lecture 21 |
Room Acoustics HRTF Measurement |
04/17/2006 |
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04/19/2006 |
Wave Field Synthesis |
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04/24/2006 |
Cortical Model |
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04/26/2006 |
Projects: 1. Independent Component Analysis for Audio 2. Automatic Echo Cancellation, Noise removal and noise suppression 3. Creating room transfer functions for graphically prescribed models 4. Others in the lecture |
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05/01/2006 |
Lecture 25 |
Graphics based algorithms for Architectural Acoustics Sttetner and Greenberg (1989) Takala and Hahn (1992) Funkhouser et al. (Siggraph 98, 99) Tsingos et al. (Siggraph
2001) Course notes
Siggraph 2002 (Funkhouser
et al.) |
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Useful Links
MATLAB resources:
Introductory Tutorials
Slightly more advanced Tutorials
MATLAB tutorial from University of New Hampshire
MATLAB tutorial/reference from University of Florida
MATLAB tutorial from Michigan Technological University
More complete references/tutorials/FAQs