Play with the theta parameters?

[FengLoveBella]

Rotation-only spatial transformer networks. I want to learn a theta parameters which only rotation support. I know rotation mean [cos(theta), -sin(theta),sin(theta),cos(theta)], but how to constrain the these parameters to let the stn only support rotation.

[daerduoCarey]

You have to write your own layer to use the input theta to generate output 2x2 matrix. It is not hard to do. Or, you can just predict the four values and put some additional loss to constraint the matrix to be a rotation matrix.