CMSC828D : Algorithms and systems for capture and playback of spatial audio.
Time: MW from 3:304:45; 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 midterm 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 midterm 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%, MidTerm 25%, Final 35%
DATE 
LECTURE 
CONTENTS 
01/25/2006 
Introduction to the course and audio in computing 

01/30/2006 
Physical Acoustics 

02/01/2006 
The wave equation. Helmholtz equation. Boundary Conditions. Properties of solutions. 

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 

02/08/2006 
Separation of Variables. Fourier Series. 

02/13/2006 
FFT Homework Problems 1, 2, 8 

02/15/2006 
Introduction to Signal Processing (based on material from CERN) 

02/20/2006 
Convolution, Impulse Response (based on Berkeley EE course) 

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”) 

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 

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 

03/08/2006 
Beamforming 

03/13/2006 
Spherical arrays 

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, 

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 
Planewave representation HRTF and spherical array based playback 

04/05/2005 
Transaural rendering Commercial speakerbased spatial audio systems 

04/10/2006 
Room Acoustics 

04/12/2006 
Lecture 21 
Room Acoustics HRTF Measurement 
04/17/2006 


04/19/2006 
Wave Field Synthesis 

04/24/2006 
Cortical Model 

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 

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.) 












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