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2014-01-21 07:30:28 -0600 asked a question solvepnp(), transformation output from which coordinate system?

The documentation of solvepnp is a bit unclear to me. Is the output tvec (translation) the distance from the checkerboard to the camera coordinate system? And rvec the rotation of the camera coordinate system relative to the checkerboard coordinate system?

In other words how can I use the rvec and tvec to get the position of the checkerboard frame in the camera coordinate system?

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2013-12-22 15:25:10 -0600 asked a question SolvePnP fluctuating results

I am using SolvePnP to determine the camera position. But results in world coordinates fluctuate a lot, also estimated rotation changes a lot. Are there best practices for this or recommended settings to improve the results?

I am now currently not using any flags like 'CV_ITERATIVE' but could this help?

2013-12-01 10:24:39 -0600 asked a question Initialize OutputArray for solvePnpRansac

How should the output array argument of solvePnPRansac() be initialized? I do cv::OutputArray array. But I get a:

 error: ‘array’ declared as reference but not initialized

I am not sure how big the array will be.

2013-11-08 15:18:34 -0600 answered a question How to actualize windows events without cvWaitKey

There is an answer listed here: http://stackoverflow.com/questions/18701236/cvwaitkey-slowing-capture-process-significantly-workaround

But you can also use a very short time.

2013-11-08 09:55:41 -0600 received badge  Editor (source)
2013-11-08 09:55:25 -0600 asked a question SolvePnP(), flags: which is the best method?

The solvePnP() function can use different methods:

  • CV_ITERATIVE
  • CV_P3P
  • CV_EPNP

And there is also solvePnPRansac. I can find some papers describing the methods but not a real comparison of all methods. Is there somewhere a study that compares all these methods and gives the best method per situation? Or has someone some recommendations?