opencv rvec to polar coordinates
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I am using opencv solvePnP to get the rotation and translation vectors for an image. I am not sure how to use the rotation vector. I would like to convert it to polar coordinates because then it would be easier for me to use. 

I created some test cases: 
3d point locations: (0,0,0) (0,0,1) (1,0,1) (1,0,0)
camera location: (.5, -1, .5) 
rotation vector: (1.57, 0, 0) (facing the positive y direction) 

and when I flip the corresponding pixel location corresponding points so the camera is located at (.5, 1, .5) (facing the negative y direction) the rotation vector is (1.2, 1.2, -1.2) (facing the negative y direction). I am not sure how this last vector makes it face the negative y direction...

Any advice on how this works would be much appreciated.