Interfakultativer Kreativworkshop Bild und Videoverarbeitung und Computergraphik

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Interfakultativer KreativworkshopBild- und
Videoverarbeitung und Computergraphik

• 19. Mai 2006

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Agenda

• 900 Vorstellung der Arbeitsgruppen
• 1025 Kaffeepause
• 1040 Weitere Vorstellung der Arbeitsgruppen
• 1200 Gemeinsames Mittagessen
• 1400 Vier Brainstorming Sessions
• 1600 Vorstellung der Ergebnisse und
  Abschlussdiskussion
• 1700 Ausklang

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Info-Veranstaltung

• Kplus Zentren ftwVrVis wollen neues IKT Zentrum
  (K2 Zentrum) bilden
• Infoveranstaltung am 14.6 um 1630Uhr im
  Kontaktraum
• Ebenso wird aus KplusZentrum ACV ein neues
  K1-Zentrum für Bildverarbeitung entstehen (in
  Zusammenarbeit mit ARCS)
• Infoveranstaltung vmtl. 28.6 um 1500Uhr im
  Kontaktraum.
• Geodäsie bitte mich erinnern, Informationsmaterial
  zu schicken.

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Multimedia over Wireless
19.5.2006

• Prof. Dr. Markus Rupp
• Dipl.-Ing. Olivia Nemethova

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Research focus video over wireless

• low resolutions
• QCIF (144x176 pixels)
• CIF (288x352 pixels)
• SIF (240x320 pixels)
• high compression
• bit rates 30-300 kbit/s
• frame rates 5-15 fps
• real-time or quasi real-time processing
• video conferencing applications
• streaming (playout buffer of 2-5 sec)
• broadcasting

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Topics and people
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Logical transmission chain
sender
channel
receiver
static or dynamic feedback
source encoding
perceived quality
processing for error resilience
error concealment
source decoding
QoS mapping, protocols
network environment (packet loss)
error detection, recovery
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Content preprocessing

• ball game video streaming
• the ball carries the most important information
• after compression small objects can disappear
• proposed approach
• initial recognition
• on line tracking of the ball
• ball sharpening/replacement

• content classification
• scene cut detection
• zoom/pan detection
• feature extraction

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System overview
initial search
Y
original sequence
processed sequence
template first N positions field color
scene change?
ball replacement
N
on the fly tracking
compression
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Initial search

• search of template ball set within the whole
  frame
• playfield presence dominant color detection
• template matching using sum of absolute
  differences
• set of candidate ball trajectories
• polygon nearest to a parabolic curve assumed as
  trajectory
• ? time consuming, not suitable for real-time

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On the fly tracking

• next position of the ball predicted
• search only in ROI centered in the predicted
  position
• adaptive ROI dimension
• partial occlusion handling

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Error propagation

• temporal (motion) prediction
• spatial prediction
• variable length (entropy) coding

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Error resilience

• structure of the stream
• size of the packets
• data partitioning (content of the packets)
• unequal error protection
• resynchronization and error detection (VLC)
• entropy code resynchronization
• error detection by watermarking
• error detection by parity
• joint source channel en-/decoding
• sequential decoding of entropy code

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Reconstruction of losses

• error concealment methods
• spatial interpolation
• temporal interpolation
• hybrid methods
• decision tree based method choice
• character of motion
• spatial information
• type and quantity of lost data
• performance criteria
• quality vs. complexity

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Video quality - encoder settings
Content Provider
End-user quality (mobile handheld terminals)

• Live TV Channels

Network Operator

• Video on Demand

Choice of codec/streaming settings

• Sports
• Movies, Music

• Interactive content

• etc

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Metric design

• test of subjective quality
• choice of objective parameters
• temporal information
• spatial information
• impairments
• design of quality metrics
• reflecting subjective
• quality

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Mean opinion score data collection
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Approaches for MOS estimation

• knowledge of the original
• distortion type
• objective parameters?quality indicators
• mixed media influence
• least squares model
• other models

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Network modelling

• measurement of the physical layer
• modelling of the error characteristic

PS Packet Switched UDP User Datagram Protocol
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Logical transmission chain
sender
channel
receiver
static or dynamic feedback
source encoding
perceived quality
processing for error resilience
error concealment
source decoding
QoS mapping, protocols
network environment (packet loss)
error detection, recovery
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Network optimization

• scheduling and priority handling
• link error prediction
• adaptive scheduling
• rate-distortion modelling
• detection of losses
• modelling of distortion
• retransmission control

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Cooperation partners

• mobilkom austria
• austrian mobile operator
• ftw.
• forschungszentrum telekommunikation wien
• NewCOM
• european network of excellence in wireless
  communications
• COST290
• traffic and QoS management in wireless multimedia
  networks

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The end


Thank you for your attention.