CODEWITHSUNDEEP
c++image-processingopencv
beaver
beaver

Reputation: 570

How to rotate an image about the image center using homography?

I am using opencv warpPerspective to generate images with different rotation to evaluate my feature point detection algorithm.

In homography matrix, the up-left 2x2 matrix is the rotation matrix, as referred here.

But the result is a rotation about the origin( the up-left corner), how can I modify the homography matrix to rotate the image about its center?

Regards.

Upvotes: 3

Views: 2217

Answers (1)

fireant
fireant

Reputation: 14530

See this matrix

enter image description here

an affine transformation that translates and rotates, center is the center of rotation. To get a homography from this just need to add the last raw [ 0 0 1]. You can use getRotationMatrix2D to compute this matrix, and then either use warpAffine or form the homography and use warpPerspective. Please let us know how it goes.

Upvotes: 4

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