1-1-9 
sequential no.. When doing pair-wise registration, 23 pairs 
of views were succeeded (shown in solid lines), while 6 
pairs failed (shown in dotted lines). Reasons for failure are 
® lack of linear features for registration; e.g. building 
surfaces are hidden under large trees in view #23~#27; 
© lack of common features due to occlusion, e.g. view 
(#6,#7) and view (#27,#28). © Large jump between 
views, e.g. view #24~#27. For those failed in automatic 
registration, assign an coarse matching by manual 
operation is required as the start point for fine adjustment. 
It is not a difficult thing when using Z-lmages, since one 
can slide or rotate a Z-lmage on another one easily by 
keyboard operations. With the help of this half-automatic 
registration method, the 29 views of laser range image 
were successfully aligned in a common coordinate system 
(Figure 11.a). However, an obvious conflicting situation 
exists between view#15 and view#16 because of error 
accumulation. Minimizing the violation to local matching is 
shown in Figure 12 and Figure 13. The final result of 
multiple views’ registration is shown in Figure 11.b. 
Figure 10. Pair-wise registering 29 views of laser range 
image of the buildings in IIS, Univ. of Tokyo. Star marks 
stand for the location of viewpoint, characters for the 
sequential no. of view. Solid line stands for a successful 
pair wise registration, while dotted lines for failed. 
(a) Aligning multiple views by pair-wise registration to 
the sensor’s coordinate system of view #1 
(b) Minimizing the violations to local matching 
Figure 11. Result of multiple views’ registration 
Figure 12. Convergence in minimizing the violation to local 
matching using hill climbing method 
Com parng the angfe between two successve vew pars w ith 
paiw ise registration result 
sequential no. 
before adjistment “HK—after adjistm ent] 
Figure 13. Violation to local matching before and after 
multiple views’ registration