What exactly do we do in non-rigid registration?

1. What is non rigid registration?
2. What is a rigid registration?
3. What is non rigid transformation?

What is non rigid registration?

Nonrigid image registration refers to a class of methods where the images to be registered have geometric differences that cannot be accounted for by similarity (global translation, rotation, and scaling) transformations.

What is a rigid registration?

In rigid image registration, the objects that needed to be aligned can simply be translated and rotated with respect to one another to achieve correspondence. In rigid image registration, the rotated images are then superimposed and registration is achieved.

What is non rigid transformation?

Non-rigid transformations change the size or shape of objects. Resizing (stretching horizontally, vertically, or both ways) is a non-rigid transformation.