M16758 – Influence of views and depth compression onto quality of synthesized views July, 2009, London Krzysztof Wegner Krzysztof Klimaszewski Marek Domański team supervisor: Marek Domański Chair of Multimedia Telecommunications and Microelectronics Poznań University of Technology, Poland
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M16758 – Influence of views and depth compression onto quality of synthesized views July, 2009, London Krzysztof Wegner Krzysztof Klimaszewski Marek Domański.
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M16758 – Influence of views and depth compression onto quality
of synthesized views
July, 2009, London
Krzysztof WegnerKrzysztof Klimaszewski
Marek Domański
team supervisor: Marek DomańskiChair of Multimedia Telecommunications and Microelectronics
Poznań University of Technology, Poland
M16758 – Influence of views 2
Multiview system
RectificationCorrection
Depth M apEstim ation
V iewSynthesis
Rendering
V iew and Depth M ap
Transm ission
D isplay
Com
pres
sion
Dec
ompr
essi
on
M16758 – Influence of views 3
Multiview system
RectificationCorrection
Depth M apEstim ation
V iewSynthesis
Rendering
V iew and Depth M ap
Transm ission
D isplay
Com
pres
sion
Dec
ompr
essi
on
M16758 – Influence of views 4
Depth map compression issues
How to compress depth maps? Can MVC be used?
How to share bandwidth between views and depth maps? Which one is more important? What is the optimal ratio?
M16758 – Influence of views 5
Depth map features Differences between depth maps and
viewsDepth Maps Viewsonly one color
componentthree color
componentslimited texture abundance of texture
prominent contoursless prominent
contoursaccurate depth value
importantaccurate value not
necessary
M16758 – Influence of views 6
Depth map decimation What is the influence of depth map
decimation on the view synthesis process?
1024
76 8
x2
1024
76 8
512
384
256
192x4
M16758 – Influence of views 7
Test setup
M VCC om pression
ViewSynthesis
A
B
C
M VCC om pression
M VCD ecom pression
M VCD ecom pression
D epth M aps
ViewsView A
View C
Depth M ap A
Depth M ap C
Transm
ission B'
M16758 – Influence of views 8
View quality measurement
M VCC om pression
ViewSynthesis
A
B
C
M VCC om pression
M VCD ecom pression
M VCD ecom pression
D epth M aps
ViewsView A
View C
Depth M ap A
Depth M ap C
Transm
ission B'
M16758 – Influence of views 9
Cameras and software The following software and camera
A single-stimulus test was conducted 15 spectators quality was rated from
5 (“imperceptible artifacts”) to 0 (“very bad with annoying artifacts”)
The original video from actual real camera was used as hidden reference.
M16758 – Influence of views 17
Subjective quality 1/3
M16758 – Influence of views 18
Subjective quality 2/3
M16758 – Influence of views 19
Subjective quality 3/3
M16758 – Influence of views 20
Optimal QD for depth map
Depth quantization parameter index QD has negligible (less than 0.2 dB decrease) impact on synthesized view quality as long its value is smaller than the following threshold estimated from the experiments
M16758 – Influence of views 21
T hresho ld QD 49 0.005 76 QP 2
M16758 – Influence of views 22
Conclusions 1/2 it is possible to transmit the depth maps using
MVC codec with sufficient quality view quality is much more important than depth
quality in terms of synthesized view quality depth bitrate can be kept as low as 10 - 20 % of
total bitrate without significant loss of synthesized view quality (for decimated depth map)
M16758 – Influence of views 23
Conclusions 2/2
for a certain range of values of quantization parameter index for depth compression (QD) , no change of synthesized view quality is noticeable
higher compression rate with comparable quality can be obtained by decimating the depth map by a factor of 2
M16758 – Influence of views 24
Recommendations We recommend to consider usage of
decimated depth map in future depth map coding experiments.