Units of image points for solvePnP

asked 2015-06-02 08:43:12 -0500

Zeno gravatar image

Hi, I am new to this subject, so please forgive the silly question. To use solvePnP, are the positions of image points needed in pixel coordinates or mm? I.e. my 2D images are x ray images. Do I need to consider image spacing?


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it's all in pixels / voxels, not mm(opencv does not know anything about your resolution/dpi here.

(just curious, - how do you get your 3d correspondences from the x-ray images?)

berak gravatar imageberak ( 2015-06-03 00:28:27 -0500 )edit

Currently, I define correspondences manually. Do you have an idea for automating this?

Zeno gravatar imageZeno ( 2015-06-10 03:52:12 -0500 )edit

depends on what you're doing. in my simple case, it was for faces, and i could easily use a premodelled 3d head, and dlib landmarks for the 2d points

berak gravatar imageberak ( 2015-06-10 05:25:08 -0500 )edit

For my understanding: The imagePoints are given in pixels. I have the objectPoints in 3d coordinate system of a tracking system in mm. Now: the pose of the object in which coordinate system??

Zeno gravatar imageZeno ( 2015-06-10 06:56:49 -0500 )edit