I know the basic flow or process of the Image Registration/Alignment but what happens at the pixel level when 2 images are registered/aligned i.e. similar pixels of moving image which are transformed to the fixed image are kept intact but what happens to the pixels which are not matched, are they averaged or something else?
And how the correct transformation technique is estimated i.e. how will I know that whether to apply translation, scaling, rotation, etc and how much(i.e. what value of degrees for rotation, values for translation, etc.) to apply?
Also, in the initial step how the similar pixel values are identified and matched?