tailieunhanh - Biomedical Engineering 2012 Part 16

Tham khảo tài liệu 'biomedical engineering 2012 part 16', kỹ thuật - công nghệ, cơ khí - chế tạo máy phục vụ nhu cầu học tập, nghiên cứu và làm việc hiệu quả | 592 Biomedical Engineering à n a The center of one patch in Sa 2 b Initialization of its correspondence assignment in Sb 1 c The center of one patch in Sb 2 d Initialization of its correspondence assignment in Sa 1 Fig. 6. The initialization for the mutual registration between level 2 and 1 using the assignment results at level 3 a b c d e f g h Fig. 7. The result of mutual registration between level 2 and 1 a e centers of two patches in Sa 2 b f centers of their correspondent patches in Sb 1 c g centers of two patches in Sb 2 where most probable correspondence assignment in Sb 1 of a e are their subpatches d h centers of the correspondent patches of c g in Sa 2 the size of the dots in b d f h represents the probability of the correspondence assignment The correspondence assignment using the graphical model based mutual registration is then carried out on them. The underlying graph topology G is selected as a random graph in which the degree of each node is at least 5 connected with 5 nearest neighbours and the íĩí d ill í. ri Íii. 1 íi A r ĩ ìí nơ rr2 rr2. CT2 1 1 ill f ill 1 e I li il YY cTt-. d 1 1 A avcidgc egiee o one noe s 0. 21 ag U D u A u AL n s seiecie as u D Al A UAL 20 . The results of the mutual registration at the coarsest level l 3 and l 2 are shown in Fig. 5. Obviously the two surfaces are already roughly aligned at the coarsest level and this shows that the proposed algorithm does not ask for any initialization. The registration result at coarser level is then used to initialize the correspondence assignment at finer level as shown in Fig. 6. It can be observed that the number of candidates of each landmark at a finer level is greatly reduced due to the initialization. The advantage of the parallel mutual registration between the two surfaces can be observed from Fig. 7. The mutual registration can explore the shape information of two surfaces and exchange correspondence assignment information between them. This Automatic Mutual Nonrigid .