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Signal Processing for Spatial Sound Control - ei.rub.de · PDF file• Dolby Axon → Audio Demonstration ... Earthquake on Feb 22, ... • Frequently used in textbooks for illustration

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Text of Signal Processing for Spatial Sound Control - ei.rub.de · PDF file• Dolby Axon →...

  • Signal Processing for Spatial Sound Control

    Dr.-Ing. Gerald Enzner

    Institut fr Kommunikationsakustik (IKA)

    Winter term, 2010/2011

  • Spatial Audio Systems Digital Signal Processing Rapid Prototyping Course Organization Student Project

    Outline

    Spatial Audio Systems

    Digital Signal Processing

    Rapid Prototyping with Matlab

    Course Organization

    Previous Student Project: HRIR Demonstrator

    Dr.-Ing. Gerald Enzner Ruhr-Universitt Bochum 2/31

  • Spatial Audio Systems Digital Signal Processing Rapid Prototyping Course Organization Student Project

    Motivation of Spatial Sound Control

    The Dimension of Spatial Sound

    spaciousness or outdoorness (e.g., wind, backgroundnoise, roads, towns, birds, distant objects)

    indoor sound characteristics (e.g., room size,reverberation, timbre, reflections, closer objects)

    sound source properties (e.g., direction, distance, size,focus, diffuseness, directivity)

    Dr.-Ing. Gerald Enzner Ruhr-Universitt Bochum 3/31

  • Spatial Audio Systems Digital Signal Processing Rapid Prototyping Course Organization Student Project

    Motivation of Spatial Sound Control

    The Dimension of Spatial Sound

    spaciousness or outdoorness (e.g., wind, backgroundnoise, roads, towns, birds, distant objects)

    indoor sound characteristics (e.g., room size,reverberation, timbre, reflections, closer objects)

    sound source properties (e.g., direction, distance, size,focus, diffuseness, directivity)

    Human Auditory System

    resolves spatial sound cues (sound characteristics)

    interacts with the acoustical environments

    performs auditory scene analysis (grouping andsegregation of sound sources)

    Dr.-Ing. Gerald Enzner Ruhr-Universitt Bochum 3/31

  • Spatial Audio Systems Digital Signal Processing Rapid Prototyping Course Organization Student Project

    Spatial Sound Using Loudspeakers

    Dr.-Ing. Gerald Enzner Ruhr-Universitt Bochum 4/31

  • Spatial Audio Systems Digital Signal Processing Rapid Prototyping Course Organization Student Project

    History and Driving Forces

    Basic Evolution of Loudspeaker Reproduction Systems

    stereophonic sound: Aders experiments 1881, Blumleinspatent 1931, consumer stereo after 1950s (Vinyl and FM)

    multi-channel stereo (3,4,5,6-channel): first, using analogmatrix encoding, then, digital low-bit-rate encoding

    standardization: ITU-R 5.1 surround loudspeaker format

    Dr.-Ing. Gerald Enzner Ruhr-Universitt Bochum 5/31

  • Spatial Audio Systems Digital Signal Processing Rapid Prototyping Course Organization Student Project

    History and Driving Forces

    Basic Evolution of Loudspeaker Reproduction Systems

    stereophonic sound: Aders experiments 1881, Blumleinspatent 1931, consumer stereo after 1950s (Vinyl and FM)

    multi-channel stereo (3,4,5,6-channel): first, using analogmatrix encoding, then, digital low-bit-rate encoding

    standardization: ITU-R 5.1 surround loudspeaker format

    Accelerators

    moving pictures industry (music industry less successful):Dolby, Digital Theater Systems, Sony, MPEG

    storage media and audio codecs: CD, DVD, Blu-ray

    consumer electronics and related technical sound quality(i.e., SNR, dynamic range, frequency range)

    low-cost integrated circuits: DSP, ASIC, FPGA

    Dr.-Ing. Gerald Enzner Ruhr-Universitt Bochum 5/31

  • Spatial Audio Systems Digital Signal Processing Rapid Prototyping Course Organization Student Project

    Aders Stereo Experiment

    Figure 3-1: The first stereophonic transmission by Clement Ader in the year 1881 (from

    Daniels, 2002): Listeners enjoy a performance of the Paris opera house transmitted by two

    telephone lines. Ader patented this stereo telephone.

    Dr.-Ing. Gerald Enzner Ruhr-Universitt Bochum 6/31

  • Spatial Audio Systems Digital Signal Processing Rapid Prototyping Course Organization Student Project

    Dolby Sorround Sound Formats

    Dolby Sorround(for home media)

    Mono OpticalSoundtrack

    Dolby Digital 5.1 (AC3 Transform Audio Coding)Dolby Digital Sorround EX (plus rearcenter channel)

    1976

    Dolby SR1987

    19991992

    (improved dynamic range)

    Dolby Stereo(left, center, right, surround)

    Dr.-Ing. Gerald Enzner Ruhr-Universitt Bochum 7/31

  • Spatial Audio Systems Digital Signal Processing Rapid Prototyping Course Organization Student Project

    Dolby Stereo/Surround Playback

    Source: Surround Sound: Past, Present, and Future, Dolby

    Dr.-Ing. Gerald Enzner Ruhr-Universitt Bochum 8/31

  • Spatial Audio Systems Digital Signal Processing Rapid Prototyping Course Organization Student Project

    Dolby Digital Playback

    Source: Surround Sound: Past, Present, and Future, Dolby

    Dr.-Ing. Gerald Enzner Ruhr-Universitt Bochum 9/31

  • Spatial Audio Systems Digital Signal Processing Rapid Prototyping Course Organization Student Project

    Virtual Auditory Space using Headphones

    Examples of Auditory Virtual Environments (AVEs):

    Dolby Axon Audio Demonstration (www.dolby.com)

    IKA-SIM (Institut fr Kommunikationsakustik)

    Dr.-Ing. Gerald Enzner Ruhr-Universitt Bochum 10/31

  • Spatial Audio Systems Digital Signal Processing Rapid Prototyping Course Organization Student Project

    Head-Related Impulse Responses (HRIRs)

    replacements

    x(k)

    yr(k)

    y(k)

    head-related impulse responses hr/(k, k) describe thefree-field acoustical transfer from sound sources to thehuman ear canal including reflection, diffraction, andrefraction of sound waves at head, pinnae, and torso:

    yr/(k) =N

    =0 hr/(, k)x(k )

    Dr.-Ing. Gerald Enzner Ruhr-Universitt Bochum 11/31

  • Spatial Audio Systems Digital Signal Processing Rapid Prototyping Course Organization Student Project

    Numerous Applications of AVEs

    auditory displays, e.g., in aircrafts and flight simulators

    design and evaluation of performance rooms / music halls

    audio effects, e.g., spatializers

    music, games, television

    usability research and product-sound design, e.g., in cars

    augmented reality, e.g., in navigation

    virtual museum, virtual tourism, audiological self-screening

    tele-conferencing, tele-presence, tele-operation

    individual interactive movie sound

    www interfaces, e.g., second-life

    . . .

    Dr.-Ing. Gerald Enzner Ruhr-Universitt Bochum 12/31

  • Spatial Audio Systems Digital Signal Processing Rapid Prototyping Course Organization Student Project

    Research Topics in Spatial Audio

    Rendering of 3D-Auditory Virtual Environments

    3D-Audio Reproduction Systems (Beyond 5.1, 7.1, 10.2)

    Increased Compatibility of Sound Systems

    Standardization of Advanced Audio Formats and Codecs

    Spatial Sound Reproduction for Telecommunications:Telepresence, Hands-free Communication

    Binaural Sound for Digital Hearing Aids

    Acoustic Fiction or Physically Precise Rendering?

    ...

    Dr.-Ing. Gerald Enzner Ruhr-Universitt Bochum 13/31

  • Spatial Audio Systems Digital Signal Processing Rapid Prototyping Course Organization Student Project

    Outline

    Spatial Audio Systems

    Digital Signal Processing

    Rapid Prototyping with Matlab

    Course Organization

    Previous Student Project: HRIR Demonstrator

    Dr.-Ing. Gerald Enzner Ruhr-Universitt Bochum 14/31

  • Spatial Audio Systems Digital Signal Processing Rapid Prototyping Course Organization Student Project

    What is a Signal ?

    A signal is a function of one or more variables, e.g., time orlocation:

    x : t x(t)

    x : t ~x(t)

    x : (u, v) x(u, v)

    Examples are:

    audio signals (captured by a microphone)

    image and video signals (captured by a camera)

    radio signals (captured by an antenna)

    biological signals (e.g., captured by electrodes)

    seismic signals (captured by accelerometers)

    Dr.-Ing. Gerald Enzner Ruhr-Universitt Bochum 15/31

  • Spatial Audio Systems Digital Signal Processing Rapid Prototyping Course Organization Student Project

    Example: Speech Signal

    0 1 2 3 4 50.8

    0.6

    0.4

    0.2

    0

    0.2

    0.4

    0.6

    0.8

    t/s

    x(t)

    Dr.-Ing. Gerald Enzner Ruhr-Universitt Bochum 16/31

  • Spatial Audio Systems Digital Signal Processing Rapid Prototyping Course Organization Student Project

    Example: CT Image

    Dr.-Ing. Gerald Enzner Ruhr-Universitt Bochum 17/31

  • Spatial Audio Systems Digital Signal Processing Rapid Prototyping Course Organization Student Project

    Example: Seismic Signals

    Earthquake on Feb 22, 2003 with centre in the Vogese and with magnitude

    5.5 (http://sdac.hannover.bgr.de).

    Dr.-Ing. Gerald Enzner Ruhr-Universitt Bochum 18/31

  • Spatial Audio Systems Digital Signal Processing Rapid Prototyping Course Organization Student Project

    What is Signal Processing ?

    Signal processing is the art of modifying signals for thepurpose of analysis, transmission, synthesis, etc.

    Typical signal processing tasks are

    filtering (e.g. highpass, lowpass)

    signal analysis and pattern recognition (e.g. ASR)

    signal compression (e.g. GSM/UMTS voice codecs)

    signal enhancement (e.g. echo and noise reduction)

    signal synthesis (e.g. auditory virtual environments)

    Various applications: audio signal processing, image andvideo signal processing, signal processing for radiocommunications, medical signal processing, etc.

    Dr.-Ing. Gerald Enzner Ruhr-Unive

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