Image Stabilisation
Guillaume EmontIgalia
Image StabilisationHoliday pictures
that picture is not by me(it is © 2011 Ugo Riboni)
...but I was there!
with a plan!
What the balloon sees
Let's go higher
Higher!
HIGHER!
I said: HIIIGHEEEER!
Ok, that will do
We wanted to take pictures for 7 days
The balloon agreed to 4 hours and a half
There was an intimate ceremonywith family and friends
Nice pics! ...now what?
Time lapse!
-- [timelapse-theory.png] [fit] [text-align=center] <span font="20">(image from wikipedia under GFDL)</span> -- [timelapse-theory.png] [fit] [text-align=center] Crazier: one frame per minute!
Removing the training wheels:No tripod.
(luckily, we have OpenCV)
Stabilisation in post-processing:
1. detect the movement (optical flow)
Optical flow: position changes of features
Stabilisation in post-processing:
2. compensate
Compensation:
OpenCV provides nice tools(but we won't talk about them here)
Optical flow: a few algorithms
Horn-Schunck
Lucas-Kanade
gst-launch-0.10 filesrc location=shaky-hippo.ogg ! decodebin ! ffmpegcolorspace ! opticalflowcorrector algorithm=1 ! ffmpegcolorspace ! xvimagesink
Err, yeah but...What about the balloon pictures?
Horn-Schunck
Lucas-Kanade
SpeededUpRobustFeature
SURF
Woohoo!
Bonus track
TODO:Check out the optical flow work by David Jordan (used for slow motion)and try to apply it to stabilisation
TODO:better compensation (tesselation?)
TODO:try more algorithms (BRIEF and ORB)
TODO:automatic optimal choice of algorithm and parameters
TODO:reimplement in C and put in -bad?
TODO:for videos: movement prediction/averaging(follow the intended movement of the cameraman)
questions?
Image credits:training wheels: CC BY-NC-SA 2.0 Dale Basler http://www.flickr.com/photos/baslercast/surf: CC BY-NC-SA 2.0 Guilherme Meneghelli http://www.flickr.com/people/iberere/last one: CC BY-NC-SA 2.0 Martin Ibert http://www.flickr.com/photos/mar_ibert/
Thanks! http://www.gitorious.org/gststabilizerhttp://balloonfreaks.mooo.com/http://emont.org/blog/http://www.igalia.com/[email protected]
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