tokens: For the purpose of ablation studies , we report the results of 1 ) NMSR , using only one scale and neural self - supervised optimization , 2 ) NMSR ( 1/8 ) , the coarsest scale of neural multi - scale self - supervised registration , 3 ) NMSR ( 1/4 ) , the second coarsest scale of NMSR , 4 ) NMSR ( 1/2 ) , the third coarsest scale of NMSR , 5 ) NMSR ( 1 ) , the final scale of NMSR after sequential multi - scale optimization , 6 ) NMSRV , NMSRV ( * ) , which use training - data optimized NMSR as an initialization and conduct self - supervised neural optimization afterwards , and 7 ) NMSRVI ( * ) , which use the neural weights from the last scale as an initialization .