Re: OpenDroneMap-dev Digest, Vol 2, Issue 11

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Re: OpenDroneMap-dev Digest, Vol 2, Issue 11

Cole
What information do you have?  I don't understand what you are trying to do.  If you are trying to find the camera position from matched keypoints on different images you need to perform homography and have >= 4 matching keypoints.  http://en.wikipedia.org/wiki/Homography_%28computer_vision%29

If you are trying to find the distance to a single point you need the camera position and where the X, Y of the point in at least 2 frames.  Take a look at epipolar lines, and well as the homography link.  There is also an excellent book called multi-view geometry.

On Mon, Mar 30, 2015 at 3:01 PM, <[hidden email]> wrote:
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Today's Topics:

   1. Bundler transformation from image to world        coordinates
      (Bruno Oliveira)


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Message: 1
Date: Mon, 30 Mar 2015 19:19:02 +0100
From: Bruno Oliveira <[hidden email]>
To: opendronemap-users <[hidden email]>,
        [hidden email]
Subject: [OpenDroneMap-dev] Bundler transformation from image to world
        coordinates
Message-ID:
        <[hidden email]>
Content-Type: text/plain; charset="utf-8"

Hello,

does anyone know how to do the inverse bundler transform?
This is waht is in the manual (
http://www.cs.cornell.edu/~snavely/bundler/bundler-v0.3-manual.html) :

*P* = *R* * *X* + *t*       (conversion from world to camera
coordinates)*p* = -*P* / *P*.z        (perspective division)*p*' = *f*
* r(*p*) * *p*   (conversion to pixel coordinates)


This explains how to transform a world point X to camera coordinates.

But how do I do the inverse transformation? (for instance, how do I
get thr x point?.....)
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End of OpenDroneMap-dev Digest, Vol 2, Issue 11
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