STOCHASTIC ASSESSMENT OF TERRESTRIAL LASER SCANNER MEASUREMENTS TO IMPROVE DATA REGISTRATION INTRODUCTION

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1 SOCHASIC ASSESSMEN OF ERRESRIAL LASER SCANNER MEASUREMENS O IMPROVE DAA REGISRAION Isma Ekhahy *, M.S. Wofgang Nemee, Pof. Insttut fü Geodäse und Photogammete ehnshe Unvestät Baunshweg Gaußstaße, 386 Baunshweg, Gemany.ekhahy@tu-bs.de w.nemee@tu-bs.de ABSRAC he egstaton of pont ouds that ae aqued fom mutpe vewponts s a fundamenta task fo ase sanne data poessng. o egste the smutaneous adjaent sans, evey san has spea tagets attahed onto the objet(s) ke pan eto-efetve, bak-whte tagets as we as suh tagets, whh have we-known geometa 3D shapes (e.g. sphees, panes, yndes, et.). hese tagets o shapes ae used as andmaks and the 3D ente oodnates ae modeed fom the ase sanne pont ouds n a oa oodnate system. o tansfom a the adjaent sans to a efeene san, the east squaes souton was used as a fttng agothm to fnd the paametes of the mode tansfomaton. Athough, east stohast modeng fo data egstaton s st a dffut task to aompsh n pate, both funtona and stohast modes need to be aefuy defned. In ths pape the mxed east squae souton was used to auate the tansfomaton paametes. Usng ths mode, the oodnates of egstaton tagets n eft and ght sans ae onsdeed as obsevatons. he advantage of ths appoah s gvng the same egstaton taget dffeent weghts n evey two adjaent sans. A stohast assessment poedue has been deveoped to take nto aount the ange between the sanne and the egstaton tagets n the eft and ght san. A ompason between uent study esuts and othe ommea avaabe softwae (Cyone 5., Austas and Panda) ndated that the eabty of the estmated tansfomaton paametes between the adjaent sans s mpoved. INRODUCION Hgh esouton tpod-mounted ase sannes ae used fo ahtetue, vtua eaty, hetage doumentaton, pesevaton and ots of v engneeng appatons. he maket offes a ot of teesta ase sannes wth (LS) dffeent system spefatons. 3D ase sannes ae assfed nto dffeent ways, but a the sanne ae vey sma to the efeto ess tota staton. Eah suveyng pojet an be dvded nto thee majo steps: data aquston, data poessng and data vsuazaton. Most of the pojets w be sanned n sevea sans that must be put togethe n a ommon efeene oodnate system. he tem egstaton o mathng ae used to desbe the same task; the egstaton of eah san nto a pedefned oodnate system s usuay pefomed by usng gound onto ponts (GCPs) whh used n Photogammet method. Dependng on eonoma, manufatue, tehna o pata easons, (LS's) data oud be egsteed by one of the foowng methods:. Fo egstaton to a pedefned oodnate system: fx the oodnates of the egstaton tagets fom tota staton gound oodnate system (GCPs) and tansfom the oa oodnates of evey san to t. he dsadvantage of ths method s usng an exta nstument (tota staton) whh w ase the ost of the pojets.. Fo egstaton to a oa oodnate system, If thee ae te ponts avaabe Fx the oodnate system fo the fst san and tansfom a the neghboung sans nto the fst one. But a the sans must be oveapped. he man dawbak of the seond method s that sans must oveapped * Coespondng Autho ASPRS 6 Annua Confeene Reno, Nevada May -5, 6

2 n a age pat, but t s pefeabe n some appatons whee the egstaton tagets usng (GCPs) ae dffut to aheve. If thee s no set of te ponts fom the ate ase, many tehnques oud be used to auate tansfomaton paametes and these tehnques depend on wthe a set of te ponts avaabe o not. If thee ae no te ponts avaabe, estabshng a set of oespondng ponts fom two data sets an be used (J. Bes et a., 99). Anothe tehnque (Djkman et a., ) by mathng dffeent sufae modes. Wth these two tehnques a the sans must be oveapped dung sannng step. None of the two tehnques s desgned to egste data smutaneousy. If we have a set of te ponts o egstaton tagets the east squaes oud be used to auate the tansfomaton paametes. he east squaes souton povdes a set of quaty paametes fo the unknowns whh measue the goodness of the ft. A. Bak-whte pan taget B. Cya aget C. Sphee tagets Fgue. Regstaton tagets. Lase Sannes ae sphea measuement systems that measue the aea of nteest wth a vey hgh fequeny. Fo eah pont one obque dstane ρ and two othogona anges θ and α ae measued, togethe wth the addtonay egsteed ntensty of the etunng sgna dstane. Eah pont s desbed n a thee dmensona oa oodnate system. he geomet eaton between these measuements and thee-dmensona nfomaton of the sannng ponts an be auated fom equaton. x snθ snα = y ρ osθ snα y osα () whee x, y and z ae oud pont oodnate, ρ s the sope dstane between ase sanne nstument and objet, θ s the hozonta ange and α s the veta ange. Bak sghtng a taget annot be aed out by usng (LS). It ASPRS 6 Annua Confeene Reno, Nevada May -5, 6

3 sans a the objets n hs fed of vew. In data poessng step, oodnates of the egstaton tagets s known when usng a spea poessng agothms. Some of (LSs) spea tagets (see fgue ) an be dstbuted n the fed of vew befoe san poess. hese tagets ae nethe eto-efetve no made fom spea mateas. he 3- D oodnates extated by some (LS) data poessng softwae, fo exampe (Lea HDS Cyone 5. and Z+F ase onto v6.6..). 3-D oodnates fo pan tagets oud be aso measued wth a tota staton n a gound oodnate system befoe o afte the sannng poess fo the egstaton pupose. Auay of aqung the oodnates of egstaton tagets depends on the auay of the measuements ( ρ,θ and α ). he dstane auay s nfuened by sevea paametes. he man paametes ae the sufae popetes (e.g. matea, oughness, and oo), the ange of ndene and the dstane. he pesent atmosphee (tempeatue, a pessue) an aso nfuene the dstane auay. he auay of the fna ompete san objet w depends on the auay of the tansfomaton paametes between a the sans. he auay of aqung the oodnates of egstaton tagets depends on the ange between the sanne and the tagets and aso the dstbuton of these tagets aodng to fed of vew of the sanne. wo types of spea egstaton tagets have been used n ths wok. Fst type s bak-whte and seond type s poystyene sphees, the sufae oud ponts wee expoted and the ente oodnates ae ftted by usng east squaes souton. Estmaton of tansfomaton paametes oud be soved ethe by usng the ombned o paamet east squaes adjustment poedue. In ths pape, the ombned mode s utzed based on assumng set of tagets oodnates n adjaent two efeene systems ae obsevatons. A stohast assessment poedue has been deveoped to take nto aount the ange between the sanne and the egstaton tagets n the eft and ght san. Resuts of tansfomaton paametes fom the used egstaton tagets have been ompaed. Dffeent stohast modes wee empoyed wth the east squaes souton. REGISRAION MODEL he egstaton of eah san wod n any pojet s edued to the omputaton of a 3D onfoma tansfomaton. he east squaes egstaton agothm has been used to auate the egstaton paametes. Assumng that two sans and the oodnates of the egstaton tagets n two adjaent sans ae avaabe, t s equed to tansfom one of the two sans onened (e.g. the ght one ) nto the nne efeene system of the fst san (e.g. the eft one) as shown n fgue (). Assume we have the oodnates n the two systems as foowng: X = [, X, Y, Z, ] and x = [, x, y, z, ] whee X oodnate veto fo denta te tagets fom eft san and x oodnate veto fo denta te tagets fom ght san. Sae fato s not assumed between the adjaent sans, assumng the ase sanne nstument s abated befoe takng the measuements. he eaton between the two oodnate systems usng sx tansfomaton paametes w be as foowng. X Y Z = x y z x y z () whee: x, y, z ae tansatons of the ogn n the x, y, z detons and s the otaton matx. he defntons of the eements of the otaton matx s gven as foowng. ASPRS 6 Annua Confeene Reno, Nevada May -5, 6

4 = osφ osκ = osω snκ + snω snφ snκ 3 = snω snκ osω snφ osκ = osφ snκ = osω osκ snω snφ snκ = snω osκ osω snφ snκ 3 + = snφ 3 = snω osφ 3 33 = osω osφ whee ω,φ and κ ae otatons about the x, y, z axes espetvey. Fgue. Coodnate tansfomatons of mut- sannng pont ouds. ansfomaton of oodnates an be ethe nea o non-nea. In nea souton ase, the unknown s numbe w be tweve (nne fom otaton eements matx and thee tansaton) afte negetng the nfuene of the sae fato between the adjaent sans. heefoe the numbe of egstaton tagets to be measued fo evey adjaent san shoud be fou, but a hghe numbe s stongy eommended to nease the numea stabty and eabty of the souton. Fo non-nea souton, oodnates of mnmum thee taget ponts n evey adjaent sans s equed to ompute the egstaton paametes o the oentaton to the objet system but an appoxmaton vaues fo the paametes ae vey mpotant. Consdeng ony two sans to egste, the obsevatons w be the oodnates of the taget ponts fom the two sans. Fo evey egstaton taget thee equatons ae equed n the mathemata mode as foow: f f f ( x + y + z ) X L ( x + y + z ) YL ( x + y + z ) Z L = x + 3 = y + 3 = z (3) (4) 3 (5) ASPRS 6 Annua Confeene Reno, Nevada May -5, 6

5 hs mode an be soved usng the ombned east squaes adjustment mode, whh has the foowng mathemata mode: ( ˆ, xˆ ) = f (6) whee ˆ s the veto of adjusted obsevatons, xˆ s the veto of adjusted tansfomaton paametes. Wth the ombned east squaes adjustment souton the stohast mode o the vaane-ovaane matx w take the fom: σ x C Q σ (7) = σ X whee σ x and σ X ae ovaane matx of obsevatons and ndates that a ovanes ae zeo. he weght matx of the obsevatons w take the foowng fom Qx P = Q = (8) Qx Assumng that the set of oodnates n the fst san wod ae eo ess (fxed), aso equaton () oud be soved by usng the paamet east squaes adjustment mode whh take the foowng fom: ˆ = f ( xˆ) (9) he stohast mode o the vaane-ovaane matx w onsde ony the obsevaton fom the ght san, aso the weght matx of the obsevatons w take the foowng fom: [ ] P Q Q () = = x Detas of ombned east squaes souton an be found esewhee (Nemee, ). Appoxmate ansfomaton Paametes Lneazaton of the equatons need sx appoxmate vaues fo the sx unknown paametes (thee otatons anges and tansaton veto) of eah mode to the goba efeene system, beause the equatons of the tansfomaton ae not nea, and a east squaes teatve souton s apped. Many agothms an be found n teatue, to oveome ths dffuty, e.g. based on quatenon (Sanso. F, 973), othogona poustes anayss (Benat et a., ) and veto ageba (Dewtt, 996). In ths wok the appoxmaton paametes have been auated usng the onept of (Dewtt, 996) the otaton anges ae detemned n seven steps: ASPRS 6 Annua Confeene Reno, Nevada May -5, 6

6 . Seet the thee geometay stongest ponts whh wdey dstbuted base. A fomua fo the squae of the attude s gven by the equaton h a + b = b ( ) () a whee h s attude fo evey thee ponts, a, b and ae the engths of the tange see fgue 3. Fgue 3. Attude fom ongest sde and noma veto to pane Compute the noma vetos at the stongest ponts n the two sans. 3. Detemne tt and azmuth fo the noma n eah san fom equatons and 3. = tt tan + 9 () k + j azmuth = tan (3) j 4. Pefom an nta otaton of ponts n the two sans usng oespondng vaues of tt and azmuth. 5. Detemne swng by dffeene n azmuths fo the ommon ne. 6. Combne the two tts, two azmuths, and one swng nto one ovea otaton matx. 7. Fom otaton matx and ompute vaues fo ω,φ and κ. ansfomaton equaton s nea n tems of tansaton veto nta vaues ae not equed. Howeve, t oud be auated by eaange the equaton and auate a the vaues of tansaton veto. ASPRS 6 Annua Confeene Reno, Nevada May -5, 6

7 ES FIELD In ode to test the egstaton agothm and get the esuts, ase system IMAGER 53 fom the Zoe+Foehh ompany has been used to san the oss seton Wenden (about 5 ko mete away fom Baunshweg ty ente). he sanned aea s appoxmatey 5m (W) x 4m (L). abe. Image 53 System Spefatons. Measuement tehnque phase shft Veta Fed of Vew: 3 Hozonta Fed of Vew: 36 Veta Resouton:.8 Hozonta Resouton.9 Veta Auay. ms Hozonta Auay:. ms Max. veta sannng speed :, pm Max. numbe of pxes veta 5, Max. numbe of pxes hozonta: 8, Sannng tme (8, x 8, 4 se. pxe mage, tota fed of vew) Fgue 4. he ase system IMAGER 53. Fgue 5. Coss seton Wenden, dstbuton of sphee tagets and two san postons. Fgue 4 and tabe desbe the sanne system and the tehna spefatons. Fo the egstaton pupose, bak -whte pane squae tagets pnted wth sze DIN A4 have been paed and aso uneebated 4 poystyene ASPRS 6 Annua Confeene Reno, Nevada May -5, 6

8 sphees wth spea hode. Fgue 5 desbes the two postons of the san and the dstbuton of the 4 sphee egstaton tagets. Fo the two san postons, two ASCII fes fom the softwae Z+F Lase onto have been egsteed, one fe pe san; *.zfs fe wth szes: 6 and 57MB. Fgue 6 shows the two sans expoted fom the softwae Z+F Lase onto wth an ntensty mage. A. Left san B. Rght san Fgue 6. Intensty mages of the sans. Extatng Coodnates of Regstaton agets he sannng pogam Z+F Lase onto has a spea on to fnd ony the bak-whte tagets. o do ths, the use shoud manuay fnd and adjust the mouse as ose as possbe to the oss whh sepaate the bak-whte n the taget. A measued tagets have been abeed and the oodnates expoted nto the ASCII fes 4 oumns pont numbe x, y, z. hs opeaton shoud be done n evey san. abe shows the tansfomaton paametes and fttng quaty by usng the best 5 bak-whte tagets ustated. Aso, the tansfomaton paametes fom some avaabe softwae s ae ompaed, these softwae s ae Lea Geosystems HDS Cyone 5. s 3D pont oud poessng softwae fo ase sanne obsevaton. Austas s a softwae system fo automated off-ne dgta ose ange photogammet mage measuement, oentaton tanguaton and senso abaton. Panda s a pogam fo the adjustment of the netwoks and defomaton anayss wh eenty deveoped fo handng D-, D- and 3D-netwoks n engneeng suveyng (Nemee et a., 99). abe shows the esuts of the egstaton usng ou mode and ts fttng quaty as we as the esut fom Cyone, Austas and Panda softwae. We noted that no quaty fttng to desbe the goodness of the paametes when usng Cyone softwae, the dffeenes n the otaton anges ω, φ and κ wee 6'57'', 9'55'' and '8'', espetvey, aso the dffeenes n tansaton veto x, y and z wee 8.4, 6.8 and 3. mm, espetvey. he foowng seton w ove the auaton o modeng the ente of a sphee to use t as a te ponts between the adjaent sans fo the uent study. Fttng a Sphee to Pont Couds fo Data Regstaton he two sans data wee mpoted fom *.zfs data to *.mp data by usng Cyone 5.. Wth ths pogam t s possbe to wok wth 3D wndows to seet and expot the oud ponts fo evey sphee nto ASCII fes 4 oumns (x, y, z, ntensty). Sphees sanned fom dffeent postons n dffeent sans ae used as thee-dmensona tagets. he man advantage of the sphea tagets s the vewng fom any ase standpont. In ou tests, 4 poystyene sphees wth nun abated adus about 5 m. ASPRS 6 Annua Confeene Reno, Nevada May -5, 6

9 abe. ansfomaton paametes and fttng quaty by usng bak-whte tagets Paametes Fttng quaty of the paametes Ou souton Cyone Austas& Panda Ou souton Cyone Austas& Panda ω - 6'4'' - 33''' - 6'4'' 359'' na * 3'' φ '6'' - ''' '6'' 77'' na 58'' κ -44 '39'' -44 '47'' 44 '39'' 59'' na 4'' x m m m 3.9 mm na 6. mm y m m m 7.5 mm na 6. mm z.8 m.797 m.8 m.7 mm na 8.5 mm o be abe to use the sphees, the paametesaton shoud not depend on the sphee wthe t s paty ouded o not. A sphee an be desbed as foows: he adus ( ) he ente o-odnates (, ) x y, z Fndng the paametes of a sphee s an teatve poess, theefoe, nta vaues have to be detemned befoehand. he adus and the ente of the sphee an be soved fom the foowng equaton: ( x x ) + ( y y ) + ( z z ) = (4) x y, z x y, z Whee:, Cente oodnate,, Sufae oodnates fo the sphees fom ase sanne. hs method s based on mnmzng the mean squae dstane fom the sphee to the data ponts. Sne ths s a nonnea pobem, nta vaues ae needed fo the paametes of the sphee. v = ( x x ) + ( y y ) + ( z z ) (5) Appoxmate vaues fo the paametes ae povded by (Ebey, D.999) agothm. he poposed agothm has been mpemented n C++ pogam, n ode to auate the paametes of sphee. he foowng two fgues desbe the eaton between the dstane fom the sphee tagets to the sanne and the ente oodnates auay. Fgue 7 epesents the eaton between the auay of ente oodnates of modeed 4 sphees fom two sans. he esuts show good eaton between the ange fom the sanne and the auay of sphee paametes. * na means not avaabe by the softwae ASPRS 6 Annua Confeene Reno, Nevada May -5, 6

10 9 8 5 StDev_x Auay of ente oodnates (mm) StDev_x StDev_y StDev_z StDev_xyz Auay of ente oodnates (mm) 4 3 StDev_y StDev_z StDev_xyz Range fom the sanne (m) Range fom the sanne (m) A. San B. San Fgue 7. Auay of ente oodnates of modeed sphees aodng to the ange fom Lase sanne. Stohast Assessment fo aget Coodnates Lase sanne obsevatons ae ontamnated by sevea knds of eos and bases, namey, the sufae popetes (e.g. matea, oughness and oo), the ange of ndene and the dstane between the sanne and the taget. Aso fo ong ange appatons the pesent atmosphee (tempeatue and a pessue) nfuenes the dstane auay. Due to the ompex natue of these eos, goous modeng, n genea, annot be aheved.he emanng eo omponents must be modeed stohastay though the east squae stohast mode (the obsevaton ovaane matx). he vaanes (dagona eements of the ovaane matx) desbe the statsta quaty whe the ovaane (off-dagona eements) desbes the oeaton between the obsevatons. he eatve auay 3D oodnates of te ponts whh used n data egstaton s aounted by weghtng the moe pese one hghe than the ess one. Equaton 6 shows a mode of the eatve weght matx fo one te pont whh has 3D oodnates fom two adjaent san. ρ P = ρ ρ ρ ρ ρ (6) whee ρ s the ange between the sanne and egstaton taget n ght san and ρ the ange between the sanne and the same egstaton taget n eft san. Aodng to the assumpton that the vaane of ente oodnates of the sphee te taget s popotona to the ange between the sphee ente and the sanne, thee anddates o modes fom the eatve weght matx wee used wth the east squae souton to auate tansfomaton paametes and the mpat on the quaty of the unknowns that wee anaysed: An dentty weght matx (Equa weghts) P =. he ange between the sanne and the taget dependent (.e. σ = σ x = σ y = σ z ange ). he ange squae between the sanne and the taget dependent (.e. σ = σ = σ = σ ange ). x y z ASPRS 6 Annua Confeene Reno, Nevada May -5, 6

11 Wth the ast two eatve weght modes, the nfuene of the ess pese te pont s edued and the moe pese s neased that means bette esuts fo the data egstaton s expeted. abe 3. ansfomaton paametes and the fttng quaty by usng sphees tagets. Equa weghts Paametes Weghted ange Weghted ange Fttng quaty of the paametes Equa weghts Weghted ange Weghted ange ω - 6'4'' - 6'4'' - 6'4'' 53'' 7'' 86'' φ - '45'' - '46'' - '46'' 39'' 3'' 6'' κ -44 4'57'' -44 4'54'' -44 4'47'' '' 9'' 3'' x m 4.44 m m 9. mm 7.7 mm 7. mm y m m m.7 mm 9.5 mm 8.8 mm z.955 m.955 m.955 m. mm.4mm 9.8 mm abe 3 shows the tansfomaton paametes and the fttng quaty by usng thee dffeent eatve weght matx modes. he ange squae dependant mode gave the best esuts. CONCLUDING REMARKS In ths pape, a bakgound about the agothms and some tehnques fo data egstaton has been pesented. he ombned east squaes as a method fo data egstaton has been used to auate the tansfomaton paametes. It maxmzes the auay of the ompete 3D san mode by aowng eah ndvdua oodnate of egstaton tagets n both goba and oa systems to be weghted. A ea test has been aed out n ode to evauate the egstaton paametes and the fttng quaty by usng two types fom spea egstaton tagets (bak-whte and poystyene sphee tagets). By usng the softwae Z+F Lase onto, t s possbe to extat manuay the 3D nfomaton fo the bak-whte tagets. Agothms fo fttng a sphee to pont ouds to be used fo data egstaton wee aso pesented. est esuts wth ea data have been done, esuts fom ou souton and some ase sanne data poessng softwae suh as, Cyone 5., Austas and Panda, wee ompaed. Aodng to the egstaton tagets type, the sphee tagets gave the best esuts. he auay of extatng sphee paametes s ange dependent. By usng ange wth the eatve weght matx whh used n ombned mode to auate tansfomaton paametes between adjaent san the esuts ae mpoved. REFERENCES Austas use s manua, (5). Bahndof, J. (5). Veknüpfung von LaseSans, 65. DVW-Semna eestshes Lasesannng (LS). Band 48, Wßne-Veag, Augsbug. Benat, A., Cosa, F., (). Geneazed Poustes Anayss fo Sze and Shape 3-D Objet Reonstutons. In: Guen, A., Kahmen, H. (Eds.), Opta 3-D Measuement ehnques V, Venna, pp Bes, P.J. and MKay, N.D., (99). A Method fo Regstaton of 3-D Shapes. IEEE ansatons on Patten Anayss and Mahne Integene, 4(): Cyone use s manua, Deembe. Dewtt, B. (996). Inta appoxmaton fo the thee-dmensona onfoma oodnate tansfomaton. Photogamet Engneeng and Remote Sensng, 6: Djkman, S.., van den Heuve, F.A., (). Sem Automat Regstaton of Lase sanne Data. IAPRS, XXXIV- 5: -7. ASPRS 6 Annua Confeene Reno, Nevada May -5, 6

12 Ebey, D. (999). Least Squaes Fttng of Data. In: sft.pdf, aessed mash 3. Ekhahy, I. and Nemee, W. (6). Fttng sphee tagets and the mpat on data egstaton auay fo eesta ase sanne. Ffth Intenatona symposum uksh-geman Jont Geodet Days. Mah 9-3, Ben, Gemany. Ekhahy, I. and Nemee, W. (6). Optmzaton and Stength Aspets fo the Geoefeenng Data wth eesta ase sanne. 3 d IAG Symposum on Geodesy fo Geotehna Stutua Engneeng and the th FIG Defomaton Measuement Symposum. Fabo, R. (3). Fom pont oud to sufae the modeng and vsuazaton pobem. Intenatona Ahves of Photogammety, Remote Sensng and Spata Infomaton Senes, XXXIV-5/W Godon, S,J. and D.D. Lht, (4). eesta ase sannes wth a naow fed of vew: the effet on 3D eseton souton. Suvey Revew, 37(9). Johansson, M. () Expoaton nto the Behavou of hee Dffeent Hgh-Resouton Gound-Based Lase Sannes n the But Envonment. Poeedngs of the CIPA WG 6 Intenatona Wokshop on Sannng fo Cutua Hetage Reodng. Ken, F. (3). Automatsete Modeeung von Bauweksgeometen aus 3D-Lasesanne-Daten. PhD thess, U Baunshweg, Insttut fü Geodäse und Photogammete, Gemany. Lea Geosystems HDS Cyone 5.: 3D Pont Coud Poessng Softwae fo Suveyos and Engnees. Saon, M. and Foan, G. (3). Independent Mode anguaton of eesta Lase Sanne Data. he Intenatona Ahves of the Photogammety, Remote Sensng and Spata Infomaton Senes, XXXIV, Pat 5/W. Nemee, W. (). Ausgehungsehnung. Ben-New Yok: Wate de Guyte. Nemee, W. and engen, D. (99). PANDA he Softwae Pakage fo Pese Engneeng Netwoks. Po. nd Aeeat. Wokshop, DESY, Hambug. Nemee, W., homsen, S. and Shäfe, M. (). 3-D Geometeefassung mt eestshen Lase- sannen. In Luhmann,. (Ed.), Photogammete und Lasesannng Anwendung fü As-But- Dokumentaton und Faty-Management, (pp. 5-6), Hedebeg. Hebet Whmann. Nemee, W. and Wd, P. (995). Ensatz von Lasesannen fü de Efassung von Gebäudegeometen. In Shade, B. (Ed.), Gebäudenfomatonssysteme, (pp ), Stuttgat. Konad Wttwe. Shftenehe DVW. Sanso, F. (973). An exat souton of the oto-tansaton pobem. Photogammeta, 9, Shemme, H. (996). Gundagen de Sensok. Hedebeg, Gemany: Whmann. Stage, R. (3). eesta ase sannng tehnoogy, systems and appatons. nd FIG Regona Confeene Maakeh, Mooo. Z+F LaseConto, (5). ASPRS 6 Annua Confeene Reno, Nevada May -5, 6