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3d point reconstruction

asked 2014-05-17 06:58:36 -0500

GiulSDU gravatar image

Hi, i have two 2d points from two rectified images, they match. How can i now compute the 3d point? I have both projection matrix. thank you

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  • if you have a stereo-rig, and did stereocalibration, you can build disparity via blockmatching, and use reprojectimageto3d

  • if you don't have a Q-matrix, you will need more than 2 images, and use triangulation

berak gravatar imageberak ( 2014-05-17 07:32:30 -0500 )edit

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answered 2014-05-17 17:14:30 -0500

You could use cv::triangulatePoints:

http://docs.opencv.org/modules/calib3d/doc/camera_calibration_and_3d_reconstruction.html#triangulatepoints

It gives you homogeneous 3D points from two projection matrices and corresponding pixels.

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that works fine thanks!! i tried to crop the original images a little bit and to use the same matching algorithm as before..the problem is that i get very different 3d-points coordinates...but the object is just the same....and i did not change the position..i just cropped the image..aren t i suppose to get the same 3d point regardless to the xy coordinate of the object in the image? can you see the error somewhere? thank you

GiulSDU gravatar imageGiulSDU ( 2014-05-18 08:37:35 -0500 )edit
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Asked: 2014-05-17 06:58:36 -0500

Seen: 263 times

Last updated: May 17 '14