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Markerless Tracking using Planar Structures in the Scene

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19
lami88
05-03-2017
03:50 AM ET (US)
Wow. cool post. I’d like to write like this too – taking time and real hard work to make a great article… but I put things off too much and never seem to get started. Thanks though.I'm common rail come from sensor .
18
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06-14-2010
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  Messages 17-14 deleted by author between 10-07-2008 02:22 AM and 07-15-2008 02:32 AM
13
kalison
07-07-2008
05:39 AM ET (US)

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10
x iaoqi
06-12-2008
03:59 AM ET (US)
guangpanzhizuo
  Messages 9-7 deleted by author between 05-16-2008 08:08 AM and 07-22-2006 09:27 AM
6
Shinko Cheng
11-24-2003
10:35 PM ET (US)
I have been pondering how is it that those folks at NFL made such a stable Yellow line for the first-down line. I guess this homoraphy tracking system is one way about it. Interested readers may like to know that htere's an article in teh Spectrum from IEEE last month regarding the awesome looking yellow line on the football field and teh 2 years and 2 million dollars they spent to create such a system.

Potentially, initialization can be done by having the camera face a perfectly planar surface. Using the same point correspondence algorithm over time, it can be determined automaitcally, via neighborhood correlation matching or some such measure, that the observed is planar, and the poitns can be taken as is to compute an initial H.
5
Mike McCracken
11-20-2003
01:22 PM ET (US)
I'm a little concerned about the initialization as well - it seems like you'd need to re-initialize every time the registered planar object moved out of the frame. Would I need to manually pick out something trackable to this algorithm every time I changed what I was looking at?
4
Neil Alldrin
11-20-2003
04:06 AM ET (US)
In the first paper, I'm wondering how well the "automatic plane detection" works. They argue that the best homography for the whole image will correspond to the homography for the largest plane in the image, but I'm not sure how robust this is. I'm also a little confused about how much hand initialization is going on. They say they specify the plane for the initial homography, but then they say something about setting "the boundary to the convex hull of the 2D points" for initialization...

And I guess my answer to Matt's question about where this will fail: scenes without planar surfaces, scenes where the planar surface has no texture (no corners will be detected), sequences where the initial plane moves out of view before a second plane becomes visible...

The outer space scenario is somewhat interesting. Since any translational motion will be miniscule compared to the distances between stars, all motion will be approximately rotational, meaning a homography will exist. The problem of course is that this doesn't really provide a frame of reference for synthesized objects since translation can't be detected.
3
Matt Clothier
11-20-2003
02:57 AM ET (US)
I've got a "fun" scenario where the plane technique will fail. For you Star Trek fans out there, imagine trying to do AR in outer space. If you have an image of just stars, there really is no way to determine a plane (especially since each star could exist in its own plane). Of course, I don't think this is something that we will have to worry about for a while. ;)
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