browsing large image datasets through voronoi diagrams
DESCRIPTION
Browsing large image datasets through Voronoi diagrams. Paolo Brivio , Marco Tarini , Paolo Cignoni. Targeted image datasets. Fairly large datasets (i.e. 1000s images) cannot be all visible at the same time Non-uniform image aspect ratio landscape vs portrait image orientation - PowerPoint PPT PresentationTRANSCRIPT
Browsing large image datasetsthrough Voronoi diagramsPaolo Brivio, Marco Tarini, Paolo Cignoni
• Fairly large datasets (i.e. 1000s images)• cannot be all visible at the same time
• Non-uniform image aspect ratio• landscape vs portrait• image orientation
• Total ordering• e.g. time of shot, some ordering defined over calibration,
user-defined sequence, etc.• Allow to specify per-image importance• i.e. each image represents a subset of the dataset
Targeted image datasets
• Rectangular grid of image thumbnails• [opt] on scrolling panels
Conventional image browsers (fullscreen)
Explorer
by Microsoft
Image
by Google
FastStone
Picasa3
by Google
• Sequence of image thumbnails• [opt] scrollbars or buttons
PhotoC
loudby IS
TI-CN
RFastS
toneConventional image browsers (thumbnail bars)
Picasa3 by G
oogle
Other drawbacks: non-uniform aspect ratios
wasted space
Google Im
age
A new type of thumbnail bar
focusimage
Thumbnail sizes
focusimage
far from focus:small thumbnails
near to focus:large thumbnails
Thumbnail sizes
focusimage
thum
bnai
l siz
e
distance from focusin image list0
(focus image)±10 ±20
Clustering images
focusimage
far from focus:each thumbnail
represents many images
near to focus:1 thumbnailfor 1 image
Selecting visible images
focusimage
41 2 3 5 6 7
visibleimage
hiddenimage
repr
esen
tativ
enes
s
imagenumber
custo
m
fuctio
n
focus
Spatial ordering
focusimage
previous imagesin the ordering
following imagesin the ordering
x-axis: image ordering respected
y-ax
is:
arbi
trar
y
• Define a parametric domain in which the ordering is enforced• Arbitrary thumbnail-bar shape
custom parametric
function
Not only horizontal thumbnail bars
Parametric domain
Thumbnail-bar shape
enforce ordering
Transitions
focusimage
new focus
focusimage
Packing of thumbnails• arbitrary bar shape• irregular shaped
thumbnails• varying size• fitting
aspect/orientation• image ordering respected• 1 thumbnail per image
cluster
Transitions
newfocus
Packing of thumbnails• arbitrary bar shape• irregular shaped
thumbnails• varying size• fitting
aspect/orientation• image ordering respected• 1 thumbnail per image
cluster
Animated transition
withtemporal
coherence
Autorecentering Voronoi diagrams
• Voronoi diagram:• given a set of 2D “seeds” inside a 2D figure F• partition F into as many “regions”• a point belongs to the region of the closest seed
• Autorecentering step (Lloyd relaxation):• move seed (●) of each region in its barycenter (+)
x nx 1
Taming autorecentering Voronoi diagrams
Taming autorecentering Voronoi diagrams 1/2
• Weighting for region size differentiation• Power Diagram
• Dynamic weight balancing • match required region sizes• smooth transitions
• including: smooth appear/disappear of regions• Ordering enforcing (over “x”)• interleaved with recentering step
• Anisotropy: make regions appropriate• …aspect ratio• …orientation (non axis-aligned)
Taming autorecentering Voronoi diagrams 2/2
• Stabilization• prevent oscillations
• Small extra forces• pulling regions toward expected positions• accelerate convergence
• Accept user “dragging” mouse gesture• Real time computation• efficient GPU implementation
Tamed autorecentering Voronoi diagrams
Packing of thumbnails• arbitrary bar shape• irregular shaped
thumbnails• varying size• fitting
aspect/orientation• image ordering respected• 1 thumbnail per image
cluster
optional bulge-out effect
Animated transition
withtemporal
coherence
Thumbnail creationor
igin
al
imag
ere
gion
sh
ape
+ resizing- cropping
- resizing+
cropping
+
Thumbnail creation: with per-image orientationor
igin
al
imag
ere
gion
sh
ape
+ resizing- cropping
- resizing+
cropping
+
Example
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