Normalize ellipses based on rotation

I know this is not a deep learning problem but I thought someone might know how.
I fitted an ellipse around multiple different objects and I’m trying to retrieve the x and y of the small objects inside each ellipse. Those coordinates however depend on the rotation of the ellipse I want them to be normalized based on the axes for example.

These are the ellipses I want to find the coordinates of the objects inside of each one and normalize them