OpenCV Q&A Forum - RSS feedhttp://answers.opencv.org/questions/OpenCV answersenCopyright <a href="http://www.opencv.org">OpenCV foundation</a>, 2012-2018.Fri, 08 Dec 2017 04:04:25 -0600does recoverPose() return up-to-scale or correct translation?http://answers.opencv.org/question/179981/does-recoverpose-return-up-to-scale-or-correct-translation/ The function recoverPose() returns the rotation and translation. While Rotation seems straight-forward to be achieved. I have doubt about the translation. Would it be a real or an up-to-scale one?Thu, 07 Dec 2017 19:04:38 -0600http://answers.opencv.org/question/179981/does-recoverpose-return-up-to-scale-or-correct-translation/Answer by Eduardo for <p>The function recoverPose() returns the rotation and translation. While Rotation seems straight-forward to be achieved. I have doubt about the translation. Would it be a real or an up-to-scale one?</p>
http://answers.opencv.org/question/179981/does-recoverpose-return-up-to-scale-or-correct-translation/?answer=180007#post-id-180007Refer to the literature, for instance: [Multiple view geometry in computer vision](https://www.robots.ox.ac.uk/~vgg/hzbook/hzbook2/HZepipolar.pdf).
> 9.6.2 Extraction of cameras from the essential matrix
>
> The essential matrix
> may be computed directly from (9.11)
> using normalized image coordinates, or
> else computed from the fundamental
> matrix using (9.12). (Methods of
> computing the fundamental matrix are
> deferred to chapter 11). Once the
> essential matrix is known, the camera
> matrices may be retrieved from E as
> will be described next. In contrast
> with the fundamental matrix case,
> where there is a projective ambiguity,
> the camera matrices may be retrieved
> from the essential matrix up to scale
> and a four-fold ambiguity. That is
> there are four possible solutions,
> except for overall scale, which cannot
> be determined.
Also, to estimate correctly the Essential matrix, the points should be in general configuration (planar points are degenerate case, see [Two-View Geometry (Course 23, Lecture D), Jana Kosecka](http://www.vision.jhu.edu/teaching/vision05/Lecture-D.pdf)).Fri, 08 Dec 2017 04:04:25 -0600http://answers.opencv.org/question/179981/does-recoverpose-return-up-to-scale-or-correct-translation/?answer=180007#post-id-180007