<html><head><meta http-equiv="content-type" content="text/html; charset=utf-8"></head><body dir="auto"><div style="-webkit-text-size-adjust: auto;">I have done something like this recently. You would be better off tearing out SURF & linking to OpenCV for all feature detection and extraction. Here is a link to the patch that OpenCV needs to support large & 16 bit imagery.</div><div style="-webkit-text-size-adjust: auto;"><br></div><div><span style="-webkit-text-size-adjust: auto;"><a href="https://github.com/Itseez/opencv/pull/1932">https://github.com/Itseez/opencv/pull/1932</a></span></div><div><span style="-webkit-text-size-adjust: auto;"><br></span><div style="-webkit-text-size-adjust: auto;">~Seth</div><div style="-webkit-text-size-adjust: auto;"><br></div><span style="-webkit-text-size-adjust: auto;">via iPhone</span></div><div style="-webkit-text-size-adjust: auto;"><br>On Mar 15, 2014, at 12:50 PM, Kshitij Kansal <<a href="mailto:kansal.k@gmail.com">kansal.k@gmail.com</a>> wrote:<br><br></div><blockquote type="cite" style="-webkit-text-size-adjust: auto;"><div><div dir="ltr">Hello Again,<div><br></div><div>@Dimitriy - Currently the <span style="font-family:arial,sans-serif;font-size:12.727272033691406px">GDALComputeMatchingPoints is using the SimpleSurf algorithm for matching points. Are you proposing that, I should implement the BRISK and then provide user the option of using either this or SimpleSurf(already implemented)? </span></div>
<div><font face="arial, sans-serif">This is indeed a very interesting thought but the problem in this is that, the </font><span style="font-size:12.727272033691406px;font-family:arial,sans-serif">GDALComputeMatchingPoints is developed with respect to the correlator project and I feel that SimpleSurf algorithm implemented there won't work on my Automatic geo-referencer as I would be considering the Multispectral Imagery and Large Datasets which are not handled in the current implementation.<b> So this will require modification to SimpleSurf as well.</b></span><br>
</div><div><span style="font-family:arial,sans-serif">I hope I have made my doubt clear? Please convey your views on this.</span><br></div><div><font face="arial, sans-serif"><br></font></div><div><font face="arial, sans-serif">@Chaitanya - In comparison to the SURF, BRISK can definitely handle the large imagery to great extent. But there is going to be some threshold upto which this algorithm will work because we must not forget that these algorithms are developed for Normal RGB images for Computer Vision related work and there usage to Remote Sensing requires some modification. I will try to look for this thing in more detail and then get back to you.</font></div>
<div><font face="arial, sans-serif"><br></font></div><div><font face="arial, sans-serif"><br></font></div><div><font face="arial, sans-serif">Also, should I prepare my initial draft of proposal based this BRISK idea only? </font></div>
<div><font face="arial, sans-serif">I have already started work in this direction and will soon post it, for review.<br></font><div><br></div></div><div>With Regards,</div><div><br></div><div class="gmail_extra"><div><div dir="ltr">
<blockquote style="margin:0px 0px 0px 0.8ex;border-left-width:1px;border-left-color:rgb(204,204,204);border-left-style:solid;padding-left:1ex">Kshitij Kansal</blockquote><blockquote style="margin:0px 0px 0px 0.8ex;border-left-width:1px;border-left-color:rgb(204,204,204);border-left-style:solid;padding-left:1ex">
Lab For Spatial Informatics,<br></blockquote><blockquote style="margin:0px 0px 0px 0.8ex;border-left-width:1px;border-left-color:rgb(204,204,204);border-left-style:solid;padding-left:1ex">IIIT Hyderabad<br></blockquote></div>
</div>
<br><br><div class="gmail_quote">On Sat, Mar 15, 2014 at 12:29 AM, Chaitanya kumar CH <span dir="ltr"><<a href="mailto:chaitanya.ch@gmail.com" target="_blank">chaitanya.ch@gmail.com</a>></span> wrote:<br><blockquote class="gmail_quote" style="margin:0 0 0 .8ex;border-left:1px #ccc solid;padding-left:1ex">
<p dir="ltr">Kshitij,</p>
<p dir="ltr">What is the performance of the proposed algorithms for very large rasters? If one of them is good with large images that's a cleaner choice without all the workaround with scaling the rasters.</p>
<p dir="ltr">--<br>
Best regards,<br>
Chaitanya Kumar CH</p>
<div class="gmail_quote"><div><div class="h5">On 15-Mar-2014 12:22 am, "Dmitriy Baryshnikov" <<a href="mailto:bishop.dev@gmail.com" target="_blank">bishop.dev@gmail.com</a>> wrote:<br type="attribution"></div>
</div><blockquote class="gmail_quote" style="margin:0 0 0 .8ex;border-left:1px #ccc solid;padding-left:1ex"><div><div class="h5">
<div text="#000000" bgcolor="#FFFFFF">
<div>Hi,<br>
<br>
I think we need to decide it here, not to create lot of proposals.
The second idea is very interesting. Maybe it worth to create some
common interface (or API) to add new methods BRISK, SURF, SIFT
etc. <br>
You can develop you realisation of BRISK and demonstrate how-to
one can use it via such common interface.<br>
E.g. in GDALComputeMatchingPoints add enum for algorithms or use
exist papszOptions.
<pre cols="72">Best regards,
Dmitry</pre>
<a href="tel:14.03.2014%2017" value="+911403201417" target="_blank">14.03.2014 17</a>:28, Kshitij Kansal пишет:<br>
</div>
<blockquote type="cite">
<div dir="ltr">Hello everyone
<div><br>
</div>
<div>Continuing the previous discussion, I would like to propose
something and the community's suggestions are welcomed/needed.
I can understand that this thread is a little old, so let me
remind you that its regarding the automatic geo-referencer
idea. The idea is also proposed on the GDAL ideas page (<a href="http://trac.osgeo.org/gdal/wiki/SummerOfCode" target="_blank">http://trac.osgeo.org/gdal/wiki/SummerOfCode</a>). </div>
<div><br>
</div>
<div>Based on the previous discussions, what came out was that
we can improve the current implementation of SIMPLE SURF in
GDAL which was developed as a part of 2012 GSOC GDAL
Correlator project, to support <b>large data</b> and <b>multi
spectral imagery</b>. And then apply this <b>modified</b> algorithm
for the geo-reference purposes. Now I have been in touch with
Chaitanya, who is willing to mentor this project, and there
are some things on which we would like to know community's
suggestions/response.</div>
<div><br>
</div>
<div>There are basically two things that can be done regarding
this project:</div>
<div><br>
</div>
<div>1. As mentioned above, we can modify the SIMPLE SURF
algorithm and make it much better for the geo-reference
purposes. Already, a lot had been discussed on this and we
have a fairly good idea about what is to be done.</div>
<div><br>
</div>
<div>2. One more thing that can be done is that we can implement
BRISK algorithm[1] instead of SURF along with the FLANN
matcher for this purpose. What advantages this thing offers is
that it is fairly fast and gives comparable outputs along with
that it works well with fairly large data sets. So we do not
need to segment the imagery as we would have done in the case
of SURF. Also added to this, this algorithm also has no patent
issues. We had a lot of problem regarding patent issues in
SIFT/SURF and we discussed them at length on the mailing list
as well. </div>
<div><br>
</div>
<div>One thing that I fell can be done is that two proposal can
be written, one for each and then community can decide
accordingly which one is more useful. Or we can decide it here
itself..? </div>
<div><br>
</div>
<div>Kindly provide your valuable comments and suggestion..</div>
<div><br>
</div>
<div>With Regards,</div>
<div class="gmail_extra"><br clear="all">
<div>
<div dir="ltr">
<blockquote style="margin:0px 0px 0px 0.8ex;border-left-width:1px;border-left-color:rgb(204,204,204);border-left-style:solid;padding-left:1ex">Kshitij
Kansal</blockquote>
<blockquote style="margin:0px 0px 0px 0.8ex;border-left-width:1px;border-left-color:rgb(204,204,204);border-left-style:solid;padding-left:1ex">Lab
For Spatial Informatics,<br>
</blockquote>
<blockquote style="margin:0px 0px 0px 0.8ex;border-left-width:1px;border-left-color:rgb(204,204,204);border-left-style:solid;padding-left:1ex">IIIT
Hyderabad<br>
<br>
</blockquote>
</div>
</div>
1. <a href="http://www.robots.ox.ac.uk/%7Evgg/rg/papers/brisk.pdf" target="_blank">http://www.robots.ox.ac.uk/~vgg/rg/papers/brisk.pdf</a><br>
<br>
<div class="gmail_quote"><br>
</div>
</div>
</div>
</blockquote>
</div>
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