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SWrucWural Analysis of HisWorical ConsWrucWions – Jerzy Jasieńko (ed) © 2012 DPNH ProcławH PolandH ISSN 0860-2395H ISBN 978-83-7125-216-7

Nbt TlliS clo sfSrAi ASSbSSMbNT lc BrfiafNd abcloMATflNS iuís MaíeusNI kelson BriíoOI sicíor cerreiraPI Margarida Barbosa4I gosé AguiarR ABSToACT qhis paper deãçnstrates the use çf terrestrial laser scanning EqipF and autçãatic digital phçtçJgraããetric EAamF tççls tç depict shapes and defçrãatiçnsI tç dynaãically perceive the spatial patterns çf building defçrãatiçns and tç quantify thçse defçrãatiçns in the built structure. qhree case studies will be presentedW iF qhe Arch çf oua AugustaI a ufuth century buildingJsculpture in qrade pquareI the river dççrway çf iisbçnI iiF salflçres malaceI a usfth century oenaissance building alãçst in ruins in içuresI and iiiF a sãall hçuse in Cçiãbra’s dçwntçwnI lçcated within the prçtected area çf “gardiã da janga” natiçnal ãçnuãent. qhe first case study assessed the deviatiçn çf the built structure frçã its theçretical and cçnceptual ãçdelI the secçnd illustrates a three diãensiçnal ãçdel enhanced with depth ãaps tç visualize the aãçunt çf defçrãatiçn çf the ãasçnry walls. qhe third case study used the qip data tç visualize the building geçãetry and defçrãatiçns thrçugh dynaãic and interactive sectiçningI and tç evaluate the pçtential çf less expensive sçlutiçns that recur tç phçtçgraããetric ãçdels generated by traditiçnal caãeras and flying drçnes. eaving in ãind that histçrical cçnstructiçns pçpulate çur city centresI this paper clarifies the advantages and liãitatiçns çf qip and Aam Elçwer cçstF ãçdels. heywords: iaser scanningI Auíomaíic éhoíogrammeíryI sisual assessmeníI

aeformaíion analysisI Building uégradeI Building reírofií NK fNTolarCTflN Architectural cçnservatiçn requires a cçãprehensive analysis çf the built structureI and tç this gçal several analysis ãçdels can be cçnsideredW iF icçnicI iiF distributiveI iiiF cçnstructiveI ivF state çf cçnservatiçnI vF stratigraphicI and viF structural xNI OzI intertwined infçrãatiçn that cçntributes tç ãake better and ãçre cçnsistent decisiçns. qhe visual inspectiçn that anticipates the initial stages çf the structural analysis can be assisted and enhanced by the visualizatiçn çf three diãensiçnal ãçdels çbtained either by terrestrial laser scanning EqipF çr autçãatic digital phçtçgraããetry EAamF. tith this apprçachI defçrãatiçn patterns can be recçgnized and dçcuãented fçr cçntinuçus assessãentI and latter that can help in the calibratiçn çf the cçãputatiçnal ãçdeling çf the structural behaviçr. qhis study exeãplifies the use çf qip çr Aam surveys as geçãetric ãçdels fçr the architectural and structural analysis. OK TboobSTofAi iASbo SCANNfNd ANa afdfTAi melTldoAMMbToY oecçrding ãethçds can be classified intç direct and indirect. tith direct ãethçdsI the çbject is discretized in the field while recçrding is taking place. ln the çther handI with indirect ãethçds the çbject is thçrçughly recçrded and discretizatiçnI if it happensI takes place in a later stage at the çffice

N Assistant mrçfessçrI qechnical rniversity çf iisbçn – caculty çf ArchitectureI lããateus]fa.utl.pt O fnvited lecturerI jinhç rniversity – Civil bngineering aepartãentI nelsçn.britç]civil.uãinhç.pt P Assistant mrçfessçrI qechnical rniversity çf iisbçn – caculty çf ArchitectureI victçr]fa.utl.pt 4 mha studentI qechnical rniversity çf iisbçn – caculty çf ArchitectureI ãargarida.j.barbçsa]gãail.cçã R Assçciate mrçfessçrI qechnical rniversity çf iisbçn – caculty çf ArchitectureI jaguiar]fa.utl.pt

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xPz. qip and Aam are such ãethçdsI where the first is active and range based and the secçnd is passive and iãage based x4z. qhis ãeans that qip priãary dataI pçint clçudsI is already three diãensiçnal whilst in Aam the priãary dataI twç diãensiçnal iãagesI later relies çn a ãatheãatical ãçdel tç recçver the three diãensiçnal infçrãatiçn cçrrespçnding tç the features depicted in the iãages. ft alsç ãeans that qip systeãs have their çwn radiatiçn sçurce ElaserF that is used tç ãeasureI ãaking theã independent çf the site illuãinatiçn cçnditiçns and allçwing night use. As Aam systeãs usually recçrd the envirçnãent radiatiçnI their use is ãçre dependent çn the illuãinatiçn cçnditiçns çf the site. OKNKNK Tip workflow qip wçrkflçw cçnsists çn three stagesW iF planning the surveyI iiF field surveyI iiiF data prçcessing. mlanning cçnsists inW aF chçice çf ãçst suitable systeãI bF definitiçn çf the equipãent pçsitiçns during the surveyI accçrding tç the prçcessing ãethçdçlçgyI cF setting the pçint clçud density accçrding tç the desired level çf detail fçr dçcuãentatiçnI dF estiãating the executiçn tiãe çf the fieldwçrk. purvey executiçn cçrrespçnds tçW aF target placeãent Eif neededFI bF tçpçgraphic survey Eif neededFI cF pçint clçud acquisitiçn. aata prçcessing cçnsists çfW aF pçint clçud cleaningI bF pçint clçud çrientatiçnI cF target identificatiçnI dF ãçdel çrientatiçnI eF infçrãatiçn extractiçn and analysis. After the capture and the reãçval çf spuriçus dataI pçint clçuds are çriented relative tç a cçããçn reference systeã. iastly the ãçdel is çriented with the cçntrçl pçintsI resulting in a true scale cçherent pçint clçud ãçdelI frequently with cçlçur assigned. qhe pçint clçud ãçdel is a first prçduct çf qipI frçã which çther prçducts ãay be generatedI in particular the traditiçnal Oa drawingsI that are still the suppçrt çf chçice aãçng architects and engineers fçr the develçpãent çf their planning actiçns. BrieflyI tç prçduce a drawing it is necessary tçW iF çrientate sectiçnLprçjectiçn planesI iiF expçrt sectiçns prçduced by these planesI iiiF expçrts iãages resulting frçã the prçjectiçn çf the pçint clçuds çn thçse planesI ivF edit the iãages tç generate a final çrthç iãageI and vF iãpçrt sectiçns and çrthç iãages in CAa sçftware and prçceed tç the graphic restitutiçn. qip is nçt dependent çf textureI but it has bad perfçrãance if used tç dçcuãent specular surfaces EglassI ãirrçrsI pçlished ãetalsF çr very dark Elçw reflectanceF surfaces. qhe range çf the systeãs alsç has effect çn what can be recçrded and the precisiçn and quality çf the recçrding. OKNKOK Aam workflow Aam wçrkflçw can be divided in twç stagesW iF iãage acquisitiçnI and iiF iãage prçcessing. fãage acquisitiçn has tç fçllçw sçãe specific rules if it is intended tç prçcess theã with the pcj apprçach. fãages have tç be redundantI and features tç be recçnstructed shçuld appear in three çr ãçre iãages. Cçnsecutive iãages shçuld be taken with sãall base distancesI and the tçtal nuãber çf iãages can be ãçre than çne thçusandI resulting that it is better tç use less resçlutiçn iãages and in bigger quantity than high resçlutiçn iãages in sãall quantitiesI and spatial resçlutiçn can be achieved with sãaller distances between caãera and çbject. Aam prçcessing cçnsists çfW iF feature detectiçn in iãagesI iiF iãage ãatchingI iiiF caãera calibratiçnI ivF caãera çrientatiçn Erelative çrientatiçnFI and vF geçãetry recçnstructiçn. qhe user çnly has tç select what iãages are gçing tç be used and tç define a set çf paraãeters that have effect çn the quality and density çf the recçnstructiçn. After the recçnstructiçn is cçãpleteI it is pçssible tç scale and çrient the ãçdel. te refer tç this fçrã çf phçtçgraããetry as Aam as until recent tiães these steps were dçne ãanually with tççls like mhçtçãçdeler çr seãiJautçãatically with tççls like fãage jasterI a cuãbersçãe and tiãe cçnsuãing task where an çperatçr had tç pick ãultiple pçints çn ãultiple iãages. qçday it is pçssible tç perfçrã all thçse steps in a fully autçãatic wayI alãçst unattendedI fçr instance with the ptructure frçã jçtiçn EpcjF and jultiJview ptereç EjspF ãethçdçlçgies using tççls like sisualpcj xRz and mjspLCjsp xSzF that are able tç deal easily with several hundred iãages siãultaneçusly. Aam is highly dependent çn the texture çf çbjects since the algçrithãs used tç perfçrã the three diãensiçnal recçnstructiçn rely çn ãatching features identified in ãultiple iãages. pçI features ãust existI çtherwise autçãatic recçnstructiçn is nçt pçssible. eistçric buildings usually are rich in texturesI resulting çf Aam prçcessing dense textured pçint clçuds that in sçãe cases can equal çr supersedeI in densityI the qip pçint clçuds. lne the advantages çf Aam çver qipI is that it is ãçre versatile. cçr instanceI a caãera can be easily placed in a flying drçneI a ballççn çr a kite tç recçrd higher parts çf a building. lne çf the disadvantages

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is that it is always needed extra infçrãatiçn tç scale and çrient the ãçdels prçduced that can be cçllected with çther ãeasuring systeãs. fn çur çpiniçnI the pçssibility çf recçvering the geçãetry çf a building with a ãethçd that is less expensive and ãçre versatile than qipI represents a new field çf çppçrtunities fçr the architectural recçrding and analysis. ff a geçJreferenced ãçdel is neededI bçth situatiçns Eqip and AamF require a tçpçgraphic survey çf sçãe cçntrçl pçints. PK Teb CASb STrafbS

PKNK The “Arco da oua Augusta” qhe “Arcç da oua Augusta” Ecig. NFI built in the ufuth centuryI is a mçrtuguese natiçnal ãçnuãentI lçcated in iisbçn. fn çrder tç plan a cçnservatiçn interventiçnI a very detailed survey was required. qip was the ãain survey ãethçd and it was used tçgether with a tçpçgraphic survey tç çrient the final pçint clçud ãçdel. qhe planning çf this survey was partially ãade in the field in çrder tç include and predict cçnstraints and çbstaclesI çr perceive pçssibilities that cçuld enhance the systeã. fn this survey abçut NTS pçint clçuds were capturedI 4O çf theã using a telescçpic platfçrã lift. AdditiçnallyI OP cçntrçl pçints were surveyed with a tçtal statiçn.

cágK N pectiçn çf the “Arcç da oua Augusta” with reflectance infçrãatiçn assçciated

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fn this case studyI twç diãensiçnal data generated frçã the Pa ãçdelI and the Pa ãçdel itselfI have prçven tç be twç cçãpleãentary sçurces çf infçrãatiçn fçr the understanding çf the built structure. qwç diãensiçnal data allçwed recçgnizing the theçretical ãçdel çf the geçãetry underlying the cçnstructiçnI in particularI the stereçtçãy çf the ãain dçãe çf the arch. qhe reasçn why this was easily dçne with the analysis çf twç diãensiçnal data was because that replicated the cçnceptual and çperative fraãewçrk çf the architectI the ãultiple views systeã derived frçã descriptive geçãetry. crçã that layçut it was pçssible tç place a hypçthesis çn the geçãetric rules Ecig. OF

cágK O deçãetric reasçning abçut the cçnceptual nature çf the dçãe geçãetry Ecçnçidal tangent surfacesF crçã the three diãensiçnal data it was pçssible tç prçve that the hypçthesis was cçrrect Ecig. PF.

cágK P Cçãparing the theçretical ãçdel EblueI red and ãagentaF with the surveyed ãçdel EyellçwF using

hçãçlçgçus sectiçns

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qwç iãpçrtant çutcçães have resulted frçã this analysis. cirstI it was pçssible tç understand that the building represents the ãçst relevant technical and scientific knçwledge çf the tiãe çf its cçnstructiçnI what allçws us tç recçgnize a particular value çn it. pecçndI the deviatiçns frçã the theçretical ãçdel and the real cçnstructiçn are very sãall what ãeans thatI althçugh it has ãçre than NRM yearsI it dçesn’t appear tç have any significant defçrãatiçns. PKOK The “malácáo de salflores” qhis palaceI and respective farãI lçcated in içures EmçrtugalFI is a unique exaãple çf mçrtuguese civil architecture çf the usfth century. fn the last fçrty years it has been used as an agricultural warehçuse and cçrralI but recently the ãunicipality bçught the prçperty and is planning an interventiçn. qhe ãain building presents severe defçrãatiçns çn slabs and wallsI ançãalies prçbably deriving frçã the absence çf rççfs. A direct visual inspectiçn allçwed tç verify that defçrãatiçns existI that there are cracks çn wallsI and even tç perceive sçãe defçrãatiçn patternsI althçugh nç ãetric infçrãatiçn is accessible çnly by this apprçach. pince a rehabilitatiçn and restçratiçn planning is taking placeI a qip survey çf the building was accçãplished in çrder tç generate graphic data fçr that planning. qhis survey enabled an enhanceãent çf the direct visual inspectiçn. aynaãic visualizatiçn çf the three diãensiçnal ãçdel with a particular kind çf ãappingI allçwed the quantificatiçn and better understanding çf the walls defçrãatiçn. qç illustrate these defçrãatiçns depth ãaps where usedI placing reference plans and ãeasuring the distance frçã the pçint clçud tç theãI and plçtting thçse distances with a cçlçur based cçde Ecig. 4F.

cágK 4 siew çf the three diãensiçnal ãçdel with defçrãatiçn data ãapped çn the surfaces çf ãain walls

qhis kind çf infçrãatiçn can then be usedI latter tç better ãçdel the structural behaviçur çf the structure and tç plan structural interventiçn. kçtice that sçãe çf the infçrãatiçn çf the depth ãaps is related with the absence çf filling ãçrtars çn the walls and that alsç gives iãpçrtant infçrãatiçn fçr instance if cçnsçlidatiçn ãeasures are being cçnsidered. PKPK Small house án Coámbra’s downtown qhe abçve referred case studies deãçnstrate that the qip is the ãçst cçãplete and reliable sçlutiçn fçr data acquisitiçn and infçrãatiçn stçrageI but its cçst and physical restrictiçns as pçints çf sightI natural çbstaclesI weightI tiãe fçr scanningI can iãply incçãplete ãçdels. PKPKNK Coméaring Tip survey wiíh Aam survey As it was previçusly statedI phçtçgraããetry is ãçre versatile because a single caãera is all that is needed fçr data acquisitiçn in the field. Althçugh ãçbile phçne çr videç caãeras ãçunted çn a drçne can be used fçr this purpçseI the quality çf iãages will have effect çn the prçcessed three diãensiçnal ãçdels. qhis study used the spcj and mjspLCjsp sçftware tç prçcess the iãages xRI Sz.

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lur experience with the cçãparisçn çf qip and Aam ãçdels Ecig. R and cig. SF has shçwn that the çverall geçãetry and defçrãatiçns can be satisfactçry depicted using this technique. qhis is an iãpçrtant result if we nçtice that Aam is ãuch ãçre versatile and cheap than qip and ãuch ãçre accessible even tç less specialized users.

cágK R Cçãparisçn çf qip ãçdel EleftF with Aam ãçdel ErightF recçnstructed with apprçxiãately NSMM iãages

taken with an imhçne 4p fãages were taken with an imhçne 4p caãera in half a day and all the prçcessing tççk apprçxiãately twç days. qhe cçunterpart çf this apprçach is that it has high hardware requireãentsI but since cçãputers are evçlving very fastI this will nç lçnger be a prçbleã in a shçrt tiãe. ft is pçssible tç partially çvercçãe this prçbleã using çnJline sçlutiçns such as mhçtçsynth Ewww.phçtçsynth.netF çr ArcPa Ewww.arcPd.beF but using a restricted nuãber çf iãagesI liãited up tç abçut PMM iãages in the phçtçsynth server.

cágK S Cçãparisçn çf qip ãçdel EleftF with Aam ãçdel EcenterF with çverlapping ErightF

qhe iãages Ecig. R rightI and cig. S centreF shçw that in the place where the texture çf surfaces was pççrer the geçãetric recçnstructiçn was alsç inexistentI which cçnstitutes çne çf the ãajçr liãitatiçns çf this techniqueI but the data retrieved can still describe the çverall geçãetry çf the cçnstructiçn. qhe cçãparisçn çf the ãçdels allçwed the çbservatiçn çf differences up tç O cãI illustrating the issues çf this technique. piãultaneçusly the difficulty in cçnnecting the inside and çutside çf a building in a single ãçdel and çccasiçnal pççr texture ãakes three diãensiçnal recçnstructiçns harderI and even ãçre difficult due tç sçãe ãçtiçn blur intrçduced by the caãera. qhe linkage çf the interiçr and exteriçr iãages çf the building was çnly achieved after a cçãprehensive series çf phçtçs çf dççrs and windçws cçnnectiçn pçints that prçvided ãçre rçbust ãçdels. PKPKOK aeformaíion assessmení After the three diãensiçnal ãçdel is prçducedI it can be further used as sçurce çf infçrãatiçn fçr several kind çf analyses. By sectiçning the ãçdel it is alsç pçssible tç extract data tç prçduce the usual twç diãensiçnal dçcuãentatiçn EplansI sectiçns and elevatiçnsFI that is what is needed fçr the general cases çf rehabilitatiçn dçcuãentatiçn.

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aefçrãatiçn analysis can be dçne with qip çr Aam ãçdelsI and can be visually assessed by dynaãically sectiçning the ãçdel with a ãçbile plan Ecig. TFI using free çpen sçurce sçftware like jeshiab sçftware. ff we cçnsider an hçrizçntal reference plan and ãçve it up and dçwnI it is pçssible tç see hçw the walls thickness changesI and tç have an idea çf walls inclinatiçn with respect tç the pluã line referenceI and further analyze these defçrãatiçns using vertical reference plans and cçlçr cçded representatiçns as shçwn abçve.

cágK T aefçrãatiçn assessãent thrçugh dynaãic sectiçning çf three diãensiçnal pçint clçud ãçdel

4K ClNCirSflNS qhis paper deãçnstrates that terrestrial laser scanning EqipF and autçãatic digital phçtçgraããetric EAamF can visually enhance the assessãentI dçcuãentatiçn and analysis çf the building geçãetry and eventual defçrãatiçns. qhe exaãples cçver several types çf building with different scales and cultural valueI and deãçnstrate that qip and eãerging technçlçgies such as Aam can be used as effective tççls tç derive significant and accurate infçrãatiçn fçr better structural analysisI better cçnservatiçn interventiçnsI and cçntribute tçwards a respectful inclusiçn çf centuryJprçven structures within the energy efficiency upgrade and sustainability xTz cçnteãpçrary effçrts xUz. pince data gathered with qip is very accurate and reliable it is pçssible tç reasçn deeply abçut the geçãetric prçperties çf the buildings and their current deviatiçns frçã the underlying theçretical ãçdelsI as deãçnstrated in the “Arcç da oua Augusta” exaãple where ufuth century stateJçfJtheJart geçãetry was recçgnizedI recçgnizing a specific value tç the building and elucidating the technical and cultural level çf the teaã that cçnceived such structure. qhe cçãparisçn çf qip and Aam three diãensiçnal ãçdels prçved that Aam ãçdels can be efficiently used fçr a cçãprehensive survey çf histçric centersI bçth frçã the exteriçr and interiçrI çpening ways tçwards a lçwer cçst apprçach tç recçrdI dçcuãentI analyze and plan in the histçric centersI with better accuracyI sãaller huãan resçurces and in shçrter tiãe than with the traditiçnal direct ãethçds. ft is iãpçrtant tç underline that it is always iãpçrtant tç cçnsider a cçstLbenefit apprçach when recçrding and dçcuãentingI and that the gçals çf the analyses tç be perfçrãed shçuld infçrã the requireãents and specificatiçns fçr the cçrrespçnding surveys. lur experience with the cçãparisçn xOz çf qip and Aam ãçdels Ecig. R and cig. SF has shçwn that the çverall geçãetry and defçrãatiçns can be satisfactçry depicted using this techniqueI an iãpçrtant result if we nçtice that Aam is ãuch ãçre versatile and cheap than qip and ãuch ãçre accessible even tç less specialized users. jçre research tç develçp surveying ãethçdçlçgies based çn Aam wçuld enable a fast and accurate survey fçr the analysis and upgrades planning in city centers whereI ãany tiãesI site cçnditiçns iãpçse severe cçnstraints due tç narrçw streets and sãall rççãs. qhe integratiçn çf flying drçnes çr ãasts cçuld present an iãpçrtant upgrade tç traditiçnal ãanual surveyingI and a real alternative tç qip survey in terãs çf cçstsI tiãe cçnsuãptiçn and alternative depictiçn çf building features and geçãetric defçrãatiçns. A better assessãent çf the built eleãents will certainly cçntribute tçwards a ãçre adequate architectural and engineering interventiçn.

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AChNltibadbMbNTS qhe authçrs wish tç thank tç cCq Ecçundatiçn fçr pcience and qechnçlçgyF fçr funding the research where the first tç case studies presented were integratedI naãely the research prçject “Cçntributiçns tç Architectural eeritage CçnservatiçnW açcuãentary jethçdçlçgy based in terrestrial digital phçtçgraããetry and Pa laser scanning”I ref.W mqaCLAroLSS4TSLOMMSI and the suppçrt fçr investigatiçn prçvided by the pcoeLBaLRNMNTLOMNM cCq grant. obcbobNCbS xNz ceifer C. ENVUVF fl prçgettç di cçnservaziçne. jilanW crancç Angeli iibri. xOz jateus i. EOMNOF Cçntributçs para ç prçjectç de cçnservaçãçI restaurç e reabilitaçãç – rãa

ãetçdçlçgia dçcuãental baseada na fçtçgraãetria digital e varriãentç laser Pa terrestres. mhd thesisI iisbçnI qechnical rniversity çf iisbçn.

xPz Bçehler t.I eeinz d ENVVVF açcuãentatiçnI surveyingI phçtçgraããetry. fn mroceedings of íhe usff CfmA pyméosium. llinda. Brazil.

x4z oeãçndinç c. EOMMSF fãageJbased ãçdelling fçr çbject and huãan recçnstructiçn. mhd thesisI wurichI pwiss cederal fnstitute çf qechnçlçgy EbqeF.

xRz tu C. EOMNNF sisual ptructure crçã jçtiçn EsçftwareF. oetrieved frçã httpWLLwww.cs. washingtçn.eduLhçãesLccwuLvsfã.

xSz curukawa v.I mçnce g. EOMMVF AccurateI aense and oçbust jultiJview ptereçpsis. fn fbbb Transacíions on maííern Analysis and Machine fníelligence EmAMf OMMVF. sçluãe POI issue U. pp. NPSOJNPTS.

xTz Britç k.I jateus i.I daãeirç j. EOMNOF rpgrade çppçrtunities fçr buildings in city centres. in mATloobB OMNO mroceedings.

xUz airective OMNMLPNLbr çf the burçpean marliaãent and çf the Cçuncil çf NV jay OMNM çn the energy perfçrãance çf buildings – accessed OMNN.NN.NM at httpWLLeurJlex.eurçpa.eu.