CODEWITHSUNDEEP
openglopencvrotationimage-rotation
aranga
aranga

Reputation: 377

Obtain Rotation Axis from Rotation Matrix and translation vector in OpenCV

I have a chessboard in two images with some angle of rotation. Lets find the rotation angle of second image with reference of first image.

For that I found the Rotation Matrix (3x3) and translation matrix (3x1) of those objects.

How can I find the Rotation Angle and Rotation Axis of object using those matrices?

Upvotes: 8

Views: 16948

Answers (2)

jochen
jochen

Reputation: 413

Already working wih openCV I would rcommend using the Rodrigues method: cv::Rodrigues(src, dst, jacobian), that computes the rotation vector if you have a rotation matrix for an argument and vice versa.

Upvotes: 1

Jav_Rock
Jav_Rock

Reputation: 22245

For every type of conversion between rotation representations you have this website euclidean space.

You will find theory and code samples of:

  • Rotation matrix to quaternion: link

  • Quaternion to axis angle: link

  • Rotations in general and all representations: link

And in relation to your question you have Axis Angle. If you have the rotation matrix R (3x3), you can obtain the angle and axis this way (see Matrix to Axis Angle):

  • angle = acos(( R00 + R11 + R22 - 1)/2);

  • Axis x,y,x:

    x = (R21 - R12)/sqrt((R21 - R12)^2+(R02 - R20)^2+(R10 - R01)^2);

    y = (R02 - R20)/sqrt((R21 - R12)^2+(R02 - R20)^2+(R10 - R01)^2);

    z = (R10 - R01)/sqrt((R21 - R12)^2+(R02 - R20)^2+(R10 - R01)^2);

Upvotes: 12

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