CHANGE DETECTION ON POINTS CLOUD DATA ACQUIRED W ITH A GROUND LASER SCANNER

Ground bas ed l as er s c anning is now wel l s ettl ed in the f iel ds of c ul tural heritage, as -buil t model l ing and monitoring appl ic ations . W e intend to us e l as er s c anning to detec t c hanges on buil ding s ites or ins ide f ac il ities , mainl y f or monitoring purpos es but al s o to be abl e to provide s ynthetic inf ormation in c as e of an emergenc y. I n both c as es , the main c ons traint is time. A minimum prec is ion on the meas ure of movements is al s o required, depending on the type of appl ic ation. Las er s c anner s eems to be the perf ec t tool f or s uc h appl ic ations as it quic kl y ac quires a l arge amount of ac c urate 3D data. But the c omparis on of s o huge datas ets impl ies the us e of appropriate s truc tures and ad-hoc al gorithms . A s pec if ic oc tree s truc ture is des c ribed, and then s everal s impl e c l oud-to-c l oud c omparis on tec hniques are pres ented. The bes t one, bas ed on the Haus dorf f dis tanc e c omputation is improved on various points . Al s o, as a f ul l automatic proc es s s eems s til l unac hievabl e, a s of tware f ramework has been devel oped. I t intends to minimiz e human intervention and theref ore prevents f rom was ting the LiDAR s peed in time-c ons uming pos t-proc es s ing operations .