The simplest case is the situation that the input and the reference images are already registered. Examples are images from hybrid acquisitions, images like parametric maps derived from a common data set, or images arising in a standard template space.
In this case, the images should already be aligned on the REFERENCE & MATCHING sub-page after loading. Please simply proceed to one of the post-processing options using the "Already matched" button indicated below.
It allows continuing in the selected environment without applying any matching procedure and. It assumes the images are aligned and that the input image was reslice to the resolution of the reference image.