+1 to what Matt and Francois have said; having rectangular trackers is very useful in some specific cases - here's a screenshot of the first example I could find: <a href="http://dl.dropbox.com/u/1470205/123531.png" target="_blank">http://dl.dropbox.com/u/1470205/123531.png </a> (it's not very clear - sorry!)<br>
Having the tracker as a smaller square would mean the pattern wouldn't be as unique, so the tracker would probably slide to the similar areas at the right, while making it a larger square would make the pattern grab the foreground area (it's hard to see, but the foreground is on the left of the image, separated by a diagonal line), also resulting in sliding, or a shorter-lived tracker.<div>
<br></div><div><meta http-equiv="content-type" content="text/html; charset=utf-8">-Nathaniel<br>
<br><div class="gmail_quote">On 21 July 2011 20:54, François T. <span dir="ltr"><<a href="mailto:francoistarlier@gmail.com" target="_blank">francoistarlier@gmail.com</a>></span> wrote:<br><blockquote class="gmail_quote" style="margin:0 0 0 .8ex;border-left:1px #ccc solid;padding-left:1ex">
<font size="2"><font face="trebuchet ms,sans-serif">@julien : they can be useful in some cases yes, especially for 2.5D tracking, corner pin, Roto,.... check out what people do with it (<a href="http://www.imagineersystems.com" target="_blank">http://www.imagineersystems.com</a>) To be honest, it wouldnt be my priority at least for matchmoe, but it is a very powerful tool, so at some point if you guys feel like it sure why not ;-) <br>
I personaly use it for all corner pin stuff. (The tutorial Sebastian did ? it's 10 times easier and faster with planar tracking) and for removal object as well, but not for matchmove purposes <br><br>@Keir : found an example just right now of a case where I add to use rectangular pattern w/o any chance to do otherwise <i>(Of course I cannot share the footage with you, so you'll have to trust me on that one, or make the test yourself :) )</i><br>
LED + motion blur. They used LED as markers on set. With motion blur the LED becomes a strip but for a start the pattern has to be as small as the LED otherwise you will get jittering. but when you get motion blur, the LED gets wider and the pattern needs to stay at the center of this strip be correct, so if the pattern is not wider than the blur LED, the marker will drift. And if you keep it square it might become a big pattern where the LED brightness is so little compare to the all rest, that the tracker won't care too much about LED anymore but mostly about what does surround it, which result also as drift<br>
<br>hope you got it :p<br><br>cheers<br><font color="#888888">F.<br></font></font></font><div><div></div><div><br><div class="gmail_quote">2011/7/21 julien michot <span dir="ltr"><<a href="http://julien.michot.fr" target="_blank">julien.michot.fr</a>@<a href="http://gmail.com" target="_blank">gmail.com</a>></span><br>
<blockquote class="gmail_quote" style="margin:0pt 0pt 0pt 0.8ex;border-left:1px solid rgb(204, 204, 204);padding-left:1ex">This is not *yet* a planar tracker!<br><br>What do you think about planar trackers, are they more efficient or easier to use? <br>
Would it be useful to implement one in libmv?<br><font color="#888888">
<br>-julien</font><div><div></div><div><br><br><div class="gmail_quote">On Wed, Jul 20, 2011 at 10:28 PM, François T. <span dir="ltr"><<a href="mailto:francoistarlier@gmail.com" target="_blank">francoistarlier@gmail.com</a>></span> wrote:<br>
<blockquote class="gmail_quote" style="margin:0pt 0pt 0pt 0.8ex;border-left:1px solid rgb(204, 204, 204);padding-left:1ex">
<font size="2"><font face="trebuchet ms,sans-serif">I don't know why you would need that. This is not planar tracking, so it really doesn't matter at the end.<br></font></font><div><font face="'trebuchet ms', sans-serif"><br>
</font></div><div><font face="'trebuchet ms', sans-serif">F.</font></div><div><font face="'trebuchet ms', sans-serif"><br></font><div class="gmail_quote">
2011/7/20 Sergey I. Sharybin <span dir="ltr"><<a href="mailto:g.ulairi@gmail.com" target="_blank">g.ulairi@gmail.com</a>></span><br>
<blockquote class="gmail_quote" style="margin:0pt 0pt 0pt 0.8ex;border-left:1px solid rgb(204, 204, 204);padding-left:1ex">
<div bgcolor="#FFFFFF" text="#000000">
<font size="-1"><font face="Tahoma">Hi everyone!<br>
<br>
It was got discussion today in #lbmv at <a href="http://irc.freenode.net" target="_blank">irc.freenode.net</a> related
on forcing pattern/search area be square.<br>
<br>
Main question: is non-square shape of marker useful in motion
tracking workflow?<br>
<br>
Some quick cases i could think could be solved just adding
offset to search area or by resizing this areas. But we've
checked some tracking applications and they allow to use
non-square markers. So</font></font><font size="-1"><font face="Tahoma"> i'm not sure it'll be good idea to stick to
squares.<br>
<br>
P.S. From UI point of view, search are could be rectangular,
just "missing" areas could be filled with black when it's
passing to libmv which would probably be optimized for squares.<br>
</font></font>
<pre cols="72">--
With best regards, Sergey I. Sharybin</pre>
</div>
<br>_______________________________________________<br>
Bf-vfx mailing list<br>
<a href="mailto:Bf-vfx@blender.org" target="_blank">Bf-vfx@blender.org</a><br>
<a href="http://lists.blender.org/mailman/listinfo/bf-vfx" target="_blank">http://lists.blender.org/mailman/listinfo/bf-vfx</a><br>
<br></blockquote></div><br><br clear="all"><br>-- <br>____________________<br>François Tarlier<br><a href="http://www.francois-tarlier.com" target="_blank">www.francois-tarlier.com</a><br><a href="http://www.linkedin.com/in/francoistarlier" target="_blank">www.linkedin.com/in/francoistarlier</a><br>
</div>
<br>_______________________________________________<br>
Bf-vfx mailing list<br>
<a href="mailto:Bf-vfx@blender.org" target="_blank">Bf-vfx@blender.org</a><br>
<a href="http://lists.blender.org/mailman/listinfo/bf-vfx" target="_blank">http://lists.blender.org/mailman/listinfo/bf-vfx</a><br>
<br></blockquote></div><br>
</div></div><br>_______________________________________________<br>
Bf-vfx mailing list<br>
<a href="mailto:Bf-vfx@blender.org" target="_blank">Bf-vfx@blender.org</a><br>
<a href="http://lists.blender.org/mailman/listinfo/bf-vfx" target="_blank">http://lists.blender.org/mailman/listinfo/bf-vfx</a><br>
<br></blockquote></div><br><br clear="all"><br>-- <br>____________________<br>François Tarlier<br><a href="http://www.francois-tarlier.com" target="_blank">www.francois-tarlier.com</a><br><a href="http://www.linkedin.com/in/francoistarlier" target="_blank">www.linkedin.com/in/francoistarlier</a><br>
</div></div><br>_______________________________________________<br>
Bf-vfx mailing list<br>
<a href="mailto:Bf-vfx@blender.org" target="_blank">Bf-vfx@blender.org</a><br>
<a href="http://lists.blender.org/mailman/listinfo/bf-vfx" target="_blank">http://lists.blender.org/mailman/listinfo/bf-vfx</a><br>
<br></blockquote></div><br>
</div>