Generation of High-Resolution Mosaic for Photo-Realistic Texture-Mapping of Cultural Heritage 3D Models

Transcription

1 The 5th Internatonal Symposum on Vrtual Realty, Archaeology and Cultural Hertage VAST (004) K. Can, Y. Chrysanthou, F. Nccolucc, N. Slberman (Edtors) Generaton of Hgh-Resoluton Mosac for Photo-Realstc Texture-Mappng of Cultural Hertage 3D Models Fabo Remondno and Jana Nederoest Insttute for Geodesy and Photogrammetry ETH Zurch, Swtzerland E-mal: Web: Abstract The work nvestgates the problem of how nformaton contaned n dfferent overlappng mages of a scene can be combned to produce larger mages of hgher qualty. The resulted mages can be used for dfferent applcatons lke forensc mage analyss, computer anmaton, specal effects, 3D model texture mappng or panorama mosac. In our case, hgh-resoluton mage mosacs of mural frescos are requred for the texturng of a 3D model that wll be used n a move producton. We developed a novel method for the dervaton of a hgh qualty mosac usng mult-resoluton and mult-temporal mages acqured from arbtrary postons and cameras. Ths method named ëconstraned mesh-wse affne transformatoní allows for seamless enhancement of the scene n the areas where hgher resoluton mages are avalable. In ths paper, we also dscuss alternatve procedures for the texture mappng of a 3D model usng exstng mult-resoluton and mult-temporal magery. The work has been done wthn a project amed at a vrtual and physcal reconstructon of the destroyed Buddha statues of Bamyan, Afghanstan. 1. Introducton The generaton of mage mosac has been deeply nvestgated n the last years. A mosac s an mage constructed by stckng together many other mages, wth the man goal of enlargng the feld of vew (ëpanoramaí) but also of ncreasng the spatal resoluton, reducng the nose and elmnatng movng objects or blur. Image mosacng nvolves the geometrc regstraton and radometrc correcton of dfferent mages, possbly acqured from the same poston. In the vson communty, the mosacng wth the am of restorng the poor qualty of the nput mages,.e. the generaton of a hgher-resoluton mage from lower resoluton mages, s called super-resoluton. In the generated hgher resoluton mage, the sharpness s mproved and the pxel sze s smaller than the lower resoluton mages. Usually a combnaton of deblurrng and fne resolvng s appled together wth a transformaton descrbed n a smple parametrc form or scene dependent. Varous algorthms have been proposed for super-resoluton [IP91, MP94, EF97, CB97, BS98, CZ98, BK00] and several software systems are avalable on the market [VI, VF]. Many algorthms work n the Fourer doman and are based on translatonal mage moton, affne, bquadratc or planar projectve mage transformatons. The success of the algorthms depends on the accuracy of the mage processng model and a wrong transformaton can degrade the fnal mage rather than enhance t. The generaton of mosac and hgher resoluton mages has many possble applcatons, lke forensc analyss, panorama mosac or 3D model texture mappng. Concernng panoramc/mosac mages, more than 30 commercal systems are avalable on the market to mosac mages acqured wth a rotatng camera. The software dstngushes n the extent of the automaton and n the requrements for the nput data and, after the sttchng, the panorama mage s warped applyng a partcular projecton for better vsualzaton [PA]. In ths artcle we report about several photogrammetrc procedures to generate frescos mage mosacs usable for the photo-realstc texturng of 3D dgtal models of cultural hertage scenes. The cultural hertage area s the Bamyan valley, Afghanstan, whle the frescos were located n the nche of the Great Buddha. The emphass of the work s put on the use of varous mages of a non planar surface, acqured wth dfferent cameras, n dfferent postons and at dfferent tme. Under these condtons, probably most of the common approaches and software systems would fal. We present a new method based on constraned mesh-wse affne transformaton, whch shows ts capabltes for correct mage mosacng, edges straghtness preservaton and mage sharpness (Secton 4.3). At frst, the scope of the project and the frescos n the nche of a destroyed Great Buddha statue are descrbed (Secton ), followed by the presentaton of the avalable mages for the requred hgh-resoluton mosacng (Secton 3). Then, we focus on the dervaton of mage mosacs usng several methods such as planar projectve mage regstraton (Secton 4.1), transformaton between mages and dgtal surface model (Secton 4.) and fnally the mentoned constraned mesh-wse affne transformaton, whch delvered satsfactory results (Secton 4.3). The full hgh-resoluton mosac s then used for the texture mappng of a 3D model. We descrbe ths procedure n the Secton 5 whle also (c) The Eurographcs Assocaton 004.

2 F. Remondno, J. Nederoest / Generaton of Hgh-Resoluton Mosac for Photo-Realstc Texture-Mappng of Cultural Hertage 3D Models dscussng some alternatve solutons for ths purpose. The photogrammetrcally reconstructed photo-realstc 3D model of the Buddha statue [GRZ04] ncludng the texture-mapped nche wll be used n a move producton whch s planned to be shown n move theatres and on TV n The Frescos n the Nches of Bamyan The famous Bamyan Buddha statues, as well as other small statues n Folad and Kakrak areas, have been destroyed by the Taleban mlta n March 001. In 003 the World Hertage Commttee has decded to nclude the cultural landscape and archaeologcal remans of the Bamyan valley n the UNESCO World Hertage Lst [UN]. The whole area contans more than 750 caves and t s n a fragle state of conservaton as t has suffered from abandonment, mltary actons and explosons. The major dangers are the rsk of mmnent collapse of the Buddha nches wth the remanng fragments of the statues, further deteroraton of stll exstng mural pantngs n the caves, lootng and llct excavaton. Among the destroyed Buddhas statues, the best known was the west Great Buddha. Its nche was excavated from the yellow rock of the clff and s approxmately 58 m hgh and 35 m depth at the base. The celng part of the nche (approxmately 15 m of dameter and 16 m depth) was rch of mural pantngs, of many dfferent colours, representng Buddha-lke fgures, brght-coloured persons, ornaments, flowers and hangng curtans (Fgure 1). 3. The Avalable Images The avalable mages of the eastern part of the Great Buddha nche were acqured wth dfferent cameras, from dfferent postons and wth dfferent objectves. As the frescos are depcted on a cave celng, the mages represent a non-planar surface and due to the dfferent acquston tmes ther radometry vares. Altogether 15 mages depctng the eastern part of the frescos were avalable for mosacng. Four of them show the full sde of the celng n the low resoluton; the rest eleven depct small detals n hgh resoluton (Fgure, 3 and 4). All mages - orgnally analogue dapostves - were scanned wth a resoluton of 0 mcrons. Low-resoluton overvew mage Detal of the low-resoluton overvew mage Part of a hgh resoluton mage Fgure : One low-resoluton overvew mage (above) and an enlarged detal of t (bottom left). The fgure at bottom rght depcts a central part of the left fgure n another, hghresoluton mage. Fgure 1: The frescos n the celng of the Great Buddha nche. The marked area n the eastern part of the nche was the subject of the hgh-resoluton mosacng. In June 003, a ceremony was held n front of the nche of the destroyed Great Buddha. The Mnster of Informaton and Culture of the Transtonal Islamc State of Afghanstan, the Ambassador of Japan and the Drector of UNESCO's Afghanstan offce, sgned a jont protocol to assst n the preservaton of the Buddhst mural pantngs of the caves surroundng the large Buddha nches. As all the pantngs of the two bg nches have been destroyed durng the explosons, the only way of documentaton and vsualzaton of the lost arts s the generaton of an accurate and photorealstc 3D model. For the dgtal reconstructon of the frescos a number of mages taken before the destructon can be used. 1 3 Fgure 3: Sketch of the whole fresco on the eastern sde of the nche [BAM01] wth the postons of 4 low- resoluton mages (No 1-4, thck lnes) as well as one hgh-resoluton mage (No 5). 5 4 (c) The Eurographcs Assocaton 004.

3 F. Remondno, J. Nederoest / Generaton of Hgh-Resoluton Mosac for Photo-Realstc Texture-Mappng of Cultural Hertage 3D Models 14 mosac. For these reasons we contnued wth the dervaton of a full mosac usng alternatve methods Fgure 4: Postons of 10 hgh-resoluton mages n the upper part of the fresco (No. 6-15). 4. Generaton of a Hgh-Resoluton Mosac In ths secton the procedures and results for the generaton of a hgh-resoluton mosac are presented. We frst descrbe a projectve mage regstraton, contnue wth the mage rectfcaton by usng the Dgtal Surface Model (DSM) and end up wth the descrpton of the constraned mesh-wse transformaton method. 4.1 Projectve Image Regstraton Two or more overlappng mages can be consdered related wth a projectve transformaton (8 parameters) f: 1. The maged scene s planar and there s an arbtrary camera moton (e.g. rotaton and translaton).. A generc 3D scene s maged wth a camera rotatng around ts vertcal axs and/or zoomng. 3. The camera s freely movng and vewng a very far away scene (e.g. aeral or satellte magery). In these cases, we can relate the D mage correspondences to a unque 3D pont. Feature based, drect or texture correlaton based approaches [CZ98, IA00, SZE94] can be employed for the mage regstraton and the parameters of the transformaton are found usng a maxmum lkelhood method or a least squares soluton. For the mosacng of the 10 hgh-resoluton mages of the upper part of the fresco (Fgure 4) we employed a commercal software package [PAN] as well as our own software for projectve mage transformaton. Thank to rch texture detals the defnton of correspondng ponts between adjacent mages was not a partcular problem. As shown n Fgure 5, the geometrc regstraton s correctly performed and the radometrc adjustment could be easly done n mage processng software (colour balance and brghtness & contrast adjustment e.g. n Photoshop). However, the horzontal whte edge s not preserved as straght as t must be (compare Fgure and Fgure 5). In addton, the further combnaton of ths projectve mosac wth the other mages was not possble, due to dstorted geometry of the projectve Fgure 5: A part of the mosac generated wth a projectve transformaton. Due to the non co-centrc mages and non planar scene, the straght edges such as the long horzontal lne at the bottom are not preserved (dashed lne n the upper mage). The lower mage shows the good geometrc ft of three adjacent mages n detal (arrows mark the begnnng and the end of seamlnes). 4. Transformaton between mages and DSM Havng a Dgtal Surface Model (DSM) avalable, an mage can be rectfed usng a projectve transformaton and at least 4 control ponts. The rectfcaton can be performed f the DSM, n the area covered by the mage, s planar or f the scene s far away from the camera. In our case, the most complcated part s to fnd control ponts between the hghly detaled contents of the frescos, as now the frescos are gone. Therefore t would be possble to rectfy and merge only mage 3 and 4 of Fgure 3, usng the corners of the small wndows as control nformaton. Due to these problems, ths knd of transformaton could not be used for our case study. 4.3 Constraned Mesh-Wse Affne Transformaton The method called ëconstraned mesh-wse affne transformatoní allows for seamless combnaton of multresoluton mages of arbtrary geometry whle preservng the orgnal form of lnear mage features. The only pre-requste s the exstence of a sutable master mage; nto the geometry of ths master mage one or more (hgher resoluton) slave mages wll be transformed. As opposed to tradtonal affne or projectve transformaton, where the transformaton parameters between two mages are the same for the whole transformed mage, the parameters of mesh-wse affne transformaton have local valdty. After defnng a mesh of dentcal trangles n both mages, the transformaton parameters are determned for each correspondng trangle. Then, the mage content of the slave mage s transformed to the geometry of the master mage trangle by trangle (Fgure 6). Such mesh-wse approach has been used e.g. for the geometrc correcton of hstorcal maps, where the old map s transformed to the geometry of a modern "master" map (c) The Eurographcs Assocaton 004.

4 F. Remondno, J. Nederoest / Generaton of Hgh-Resoluton Mosac for Photo-Realstc Texture-Mappng of Cultural Hertage 3D Models [FSM98, Bal00, Ne0]. For the dervaton of the hghresoluton mage mosacs we constran the trangular mesh generaton by defnng some ëbreaklnesí along the lnear mage features, n order to avod possble deformatons after the transformaton. 3. Computaton of transformaton parameters for each correspondng trangle. The planar affne 6-parameters transformaton s appled for ths purpose: X = a + a x a y Y = a + a x + a y (1) wth X, Y - coordnates n the master mage x, y - coordnates n the slave mage a 1 -a 6 - unknown transformaton parameters Slave mage (hgh-res) Part of the master mage (low-res) As there are always 3 dentcal ponts and thus 6 observatons, the searched 6 unknown parameters can be easly obtaned wthout adjustment. 4. Transformaton of the slave mage trangle by trangle. For each pxel X, Y of the new transformed mage, the algorthm fnds a trangle n whch t les. Ths s done by defnng a horzontal rghtward lne startng from the actual pxel and computng the number of ts ntersectons wth each trangle. When ths number s one, the pxel must lay n that partcular trangle. Usng the 6 transformaton parameters a 1 -a 6 of ths trangle, the correspondng pxel n the slave mage s found by the nverse affne transformaton: a3 x = a a ( Y a4 ) a5 ( X a a + a a a ( Y a4 ) a5 ( X a1) y = a a + a a a1) X a + a 1 () Combnaton of hgh-res (left) and low-res (rght) mage Fgure 6: Prncple of a constraned mesh-wse affne transformaton (above) and a fnal upsampled master mage (below, before radometrc adjustment). The algorthm works n the followng way: 1. Defnton of dentcal ponts between master and slave mage. The measurement of the mage coordnates can be performed manually or sem-automatcally wth least square matchng.. Generaton of the trangular mesh. It s mportant to defne the trangles n the master mage and then project them to the slave mage (not vce versa). In ths way the deformaton of the defned trangles due to the dfferent mage geometres can be avoded. Moreover, n order to preserve lnear mage features, they must be assgned as ëbreaklnesí or constrans for the trangulaton. For ths purpose, dentcal ponts lyng on the to-be-preserved lne must be defned and connected along the lne. If the defnton of constrans s not done correctly (.e. f the trangle edge cross the lne wthout an dentcal pont), the orgnally straght lnes could break on that partcular trangle edge after the transformaton. A good transton between adjacent hgh-resoluton mages can be acheved by the use of same trangles at the mage borders. The trangulaton can be done ether automatcally (n case that the Delaunay trangulator can deal wth the gven constrans) or manually. The grey value of the pxel at the poston x, y s taken for colourng the actual pxel X, Y of the new transformed mage. When more slave mages of dfferent resolutons are transformed to the geometry of the master mage, the result wll be a mult-resoluton mage. Its number of pxels n both drectons and the pxel sze n object space (pxel footprnt) are determned as follows: 1. Estmaton of a pxel footprnt for the master mage as well as for all slave mages. In our case, the pxel sze n object space was approxmately 15 mm for the master mage and 3 mm for all slave mages. For better co-referencng of the transformed mages, we performed the computaton n object space; thus, all the mage coordnates are multpled by the correspondng pxel footprnt before the transformaton.. Determnaton of a transformaton scale for each slave mage. As the parameters of mesh-wse affne transformaton are only vald wthn each partcular trangle, the transformaton scale can be approxmated as an average of scale parameters of all trangles. For our slave mages we obtaned average scale factors of Defnton of a pxel sze of each transformed slave mage by multplyng the orgnal pxel footprnt wth an approxmated transformaton scale. Ths value can be rounded up reasonably. We have set an object space pxel sze of 5 mm for all transformed slave mages. The reason for the ncrease of the pxel sze s the fact that most of the (c) The Eurographcs Assocaton 004.

5 F. Remondno, J. Nederoest / Generaton of Hgh-Resoluton Mosac for Photo-Realstc Texture-Mappng of Cultural Hertage 3D Models orgnal slave mages are frontal n respect to the photographed wall, whereas the master mage (whch s a "template" for all transformed mages) was acqured from an oblque angle. Moreover, as the slave mages depct only a small part of the scene, they represent nearly planar object, what s not the case by larger master mage. 4. Fnal geometrc mosacng. The transformed slave mages are composed and combned wth the master mage. The number of pxels and the geometrc resoluton of the fnal mage are gven by the transformed slave mages, n general by a slave mage wth the hghest resoluton. The master mage n the background s reszed accordngly (Fgure 7). In the descrbed example t needed to be magnfed 3-tmes (rato between the orgnal pxel footprnt of 15 mm and fnal one of 5 mm). Thus, the master mage has n fact the same resoluton as the transformed slave mages (5 mm), but ts grey values are dentcal for groups of 3 x 3 pxels. Image A Image B Master mage Pxels Groups of dentcal grey values Fgure 7: Mult-resoluton prncple of the fnal mosac obtaned by the constraned mesh-wse transformaton. The pxel sze and number of pxels are gven by the hghestresoluton mage (mage A). The other mages are reszed accordngly; ther grey values are not anymore unque for each pxel (mage B and master mage). Once all mages are regstered together, the radometrc dfferences between the adjacent mages can be adjusted. We use commercal mage processng packages for ths purpose (colour balance and brghtness & contrast adjustment n Photoshop). Fgure 8 and Fgure 9 show the result of mosacng n the upper and bottom part of the fresco. The upper part s a composton of 1 mages. Seven of them (No. 6-1 of Fgure 4) were transformed to the geometry of the master mage (No. 1 of Fgure 3) usng the mesh-wse approach. The other 4 border mages (No., 13, 14, 15 n Fgure 3 and Fgure 4) were transformed by applyng the tradtonal affne or projectve transformaton as descrbed n Secton 4.1, because they were not completely depcted n the master mage. The lower part of the fresco nstead conssts of 3 mages (No. 3, 4 and 5 of Fgure 3). Two of them were regstered together wth a projectve transformaton and then supermposed by the thrd, hgh-resoluton mage obtaned by a mesh-wse affne transformaton (Fgure 9). Fgure 8: Fnal hgh-resoluton mosac of the upper part of the fresco (composton of 1 mages) and two detaled vews of the hgh-resoluton contents of the frescos (arrows and lne segments mark the transton between adjacent low- and hgh-resoluton mages). Fgure 9: Fnal hgh-resoluton mosac of the bottom part of the fresco (composton of 3 mages, above). Below, a detal of a hgh-resoluton mage wth a lne (marked by the two arrows) to separate the low-resoluton part s shown. (c) The Eurographcs Assocaton 004.

6 F. Remondno, J. Nederoest / Generaton of Hgh-Resoluton Mosac for Photo-Realstc Texture-Mappng of Cultural Hertage 3D Models 5. Texture Mappng Once a 3D dgtal model of a scene s created, wth the technque of texture mappng, grey-scale or true colour mages are mapped onto the 3D geometrc surface n order to acheve photo-realstc vrtual models. Knowng the parameters of nteror and exteror orentaton of the cameras, to each trangular face of the 3D surface the correspondng mage coordnates are calculated. Then the gray-scale or colour RGB values wthn the projected trangle are attached to the face. Usually texture mappng s performed usng a frontal mage for a related part of the object. Unfortunately n close-range applcatons ths s often not satsfactory, due to varyng lght condtons durng mage acquston and not enough mage nformaton for fully or partally occluded object parts. To overcome these problems, dfferent preprocessng technques and methods of texture mappng were developed [NB95, HLM96, DTM96, PAD98, VZG01, RCM0, BR03, KP04] based on weghted functons related to the cameraís vewng angle or combnatons of optmal mage patches for each trangle of the 3D model or computng a ërato lghtngí of the textures and derve a common lght from them. Often dfferent factors affect the photo-realsm of the textured 3D vrtual model: - Image radometrc dstorton: ths effect comes from the use of dfferent mages acqured n dfferent postons or wth dfferent cameras or n dfferent daly moments (e.g. varyng lght condtons). Therefore n the 3D textured model dscontnutes and artfacts are present along the edges of adjacent trangles textured wth dfferent mages. To avod these, blendng methods based on weghted functons can be used. - Image dynamc range: dgtal mages have always a lower dynamc range than the scene. Therefore brght areas are often saturated whle dark parts contan low sgnal to nose (S/N) rato. Radometrc adjustment can be performed wth common mage processng tools. - Scene geometrc dstorton: ths knd of error s generated from an ncorrect camera calbraton and orentaton, an mprecse mage regstraton, too large trangles mesh or errors n the surface reconstructon. All these sources do not preserve detaled contents lke straght edges or bg dscontnuty changes of the surface. Accurate photogrammetrc bundle adjustment, precse mage regstraton and polygons refnement must be employed to reduce or mnmze these geometrc errors. In the followng, two methods of texture mappng of a Great Buddha nche are descrbed. Frst, nstead of the prevously generated full mosac, the orgnal mages are all orented and mapped onto the 3D model (Secton 5.1). In the second procedure we orent only the full mosac and overlay t onto the 3D model of the nche (Secton 5.). 5.1 Mult-Image Texture All the avalable mages are mported n a photogrammetrc bundle adjustment n order to recover the camera nteror and exteror parameters. As nput of the self-calbratng bundle adjustment, mage coordnates of correspondng ponts, approxmated object coordnates, approxmatons of camera postons and rotaton angles as well as approxmated camera parameters are requred. Fgure 10 shows the recovered camera poses. Afterwards each orented mage s used for the texturng of the 3D model wth our texture mappng software. The fnal textured model s exported nto VRML-format for vsualzaton. Fgure 10: The recovered camera poses. The mages of the frescos were acqured from the head of the Great Buddha as well as from a cave on the western sde of the nche (upper left corner). Because of the geometrc as well as radometrc problems, the fnal mult-mage texture mappng result was not satsfactory (Fgure 11). The geometrc nconsstences are caused by small errors of the mage orentaton, as only a lttle a-pror knowledge was avalable. These errors of the photo-trangulaton phase are then emphassed n the 3D textured model, n partcular near the border between the dfferent mages. At these places also consderable radometrc dfferences appear. Although the orgnal mages can be equalzed n the pre-processng stage, small nconsstences reman. Because the fnal texture map conssts of multple mages separately mapped onto the 3D surface, t s not easy to detect and remove them pror to the texture mappng phase. Fgure 11: The textured 3D model of the frescos. Dfferent radometrc and geometrc nconsstences are vsble n the rendered vew. 5. Full Mosac Texture After the generaton of the full mosac of the fresco usng the constraned mesh-wse transformaton, the two hghresoluton mages are orented usng a self-calbratng bundle-adjustment. Afterwards the orented mages are mapped onto the 3D geometrc model and exported n (c) The Eurographcs Assocaton 004.

7 F. Remondno, J. Nederoest / Generaton of Hgh-Resoluton Mosac for Photo-Realstc Texture-Mappng of Cultural Hertage 3D Models Fgure 1: A vew of the 3D textured model of the frescos n the nche of the Great Buddha of Bamyan, Afghanstan. On the left the textured 3D model obtaned usng the low-resoluton mages. On the rght the textured 3D model created wth the hgh-resoluton frescos mosac. VRML-format for vsualzaton (Fgure 1 and Fgure 13). In ths way the fnal photo-realstc model whch fulfls the geometrc and radometrc requrements of the move makers s obtaned. Fgure 13: A closest vew of the texture-mapped 3D model of the nche of the Great Buddha (upper mosac). 6. Conclusons In ths artcle we presented a novel method for the dervaton of accurate hgh-resoluton mage mosac usng mult-resoluton mages acqured wth dfferent cameras and from arbtrary postons. The constraned mesh-wse affne transformaton method showed the enhancement of the scene n the areas where hgher resoluton mages are avalable and the preservaton of edges straghtness. The fnal photo-realstc 3D model fulfls now the requred geometrc and radometrc accuracy. On the other hand the other dscussed approaches dd not produce satsfactory and accurate results. The presented mage-based renderng and modelng shows the potental of these technques, n partcular n case of cultural hertage areas where only mult-resoluton and mult-temporal mages are avalable for the documentaton and vsualzaton of the scenes. The unque requrement s the exstence of an ëovervewí mage to be used as master mage n the transformaton, whch s a common case n ths knd of applcatons. Therefore the presented method for the dervaton of hghresoluton mage mosac can be easly used n many other felds lke mage restoraton, text enhancements or computer generated specal effects. (c) The Eurographcs Assocaton 004.

8 F. Remondno, J. Nederoest / Generaton of Hgh-Resoluton Mosac for Photo-Realstc Texture-Mappng of Cultural Hertage 3D Models Acknowledgements The authors would lke to thank P. Bucherer, Drector of the Afghanstan Museum n Bubendorf, Swtzerland, H. Baumgartner, Enzersdorf, Austra and Dr. Vogt, KAVA, Germany, for the mages of the frescos. References [Bal00] C. Balett. Analytcal and quanttatve methods for the analyss of the geometrcal content of hstorcal cartography. IAPRS, Vol. XXXIII, Part B5, pp.30-37, 000. [BAM01] Bamyan ñ Art and Archaeologcal Researches on the Buddhst cave Temples n Afghanstan Publcaton of the Kyoto Unversty Archaeologcal Msson to Central Asa. Edted by Prof. T.Hguch, 4 Volumes, Dohosha Meda Plan, 001. [BK00] S. Baker and T. Kanade, ì Lmts on Superresoluton and How to Break Them,î Proceedngs of CVPRí000, pp , 000. [BS98] S. Borman and R.L. Stevenson, ìspatal Resoluton Enhancement of Low-Resoluton Image Sequences: A Comprehensve Revew wth Drectons for Future Research,î Techncal Report, Unversty of Notre Dame, [BR03] E. Beauchesne and S.Roy, ì Automatc Relghtng of Overlappng Textures of a 3D Modelî. Proceedngs of CVPR, pp , 003. [CB97] M. Chang and T. Boult. Local blur estmaton and superresoluton. Proceedngs of CVPR, pp 81-86, [CZ98] D. Capel and Z. Zssermann. Automated mosacng wth super-resoluton zoom. Proceedngs of CVPR98, pp , [DTM96] P.E. Debevec, C.J. Taylor, and J. Malk. Modelng and renderng archtecture from photographs: a hybrd geometry- and mage-based approach. SIGGRAPH 96 Conference Proceedngs, pages 11ñ0, [EF97] M. Elad and A. Feuer. Restoraton of Sngle Super-resoluton Image from Several Blurred, Nosy and Down-sampled Measured Images. IEEE Trans. on Image Processng, Vol. 6, no. 1, pp , [FSM98] T. Fuse, E. Shmzu, S. Morch. A study on geometrc correcton of hstorcal maps. IAPRS, Vol. XXXII, Part 5, pp , [GRZ04] A. Gruen, F. Remondno, L. Zhang. Photogrammetrc Reconstructon of the Great Buddha of Bamyan, Afghanstan. The Photogrammetrc Record, Vol.19, No.107, pp , 004. [HLM96] P. Havaldar, M.-S. Lee, and G. Medon. Vew synthess from unregstered -D mages. Proceedngs of Graphcs Interface í96, pages 61ñ69, [KP04] Km S.J. and M. Pollefeys, ì Radometrc Self- Algnment of Image Sequencesî. Proceedngs of CVPR, pp , 004. [IA00] M. Iran and P. Anandan. About drect methods. In Trggs, Zssermann, Szelsk edts, Vson Algorthms: Theory and Practce, LNCS, Sprnger Verlag, 000. [IP91] M. Iran and S. Peleg, ì Improvng Resoluton by Image Restoraton,î Computer Vson, Graphcs, and Image Processng, Vol. 53, pp , [MP94] S. Mann and R. Pcard. Vrtual Bellow: Constructng hgh qualty stlls from vdeo. Internatonal Conference on Image Processng, pp , [Ne0] J. Nederˆ st. Landscape as a Hstorcal Object: 3D-Reconstructon and Evaluaton of a Relef Model from the 18th Century. IAPRS, Vol. XXXIV, Part 5/W3, 00. [NB95] W. Nem and H. Broszo. Mappng texture from multple camera vews onto 3D-object models for computer anmaton. Proceedngs of the Internatonal Workshop on Stereoscopc and Three Dmensonal Imagng, [PA] Panogude: [PAD98] K. Pull, H. Ab-Rached, T. Duchamp, L.G. Shapro, W. Stuetzle. Acquston and vsualzaton of colored 3-D objects. Proc. ICPR, pp , [PAN] Panofactory: [RCM0] C. Rocchn, P. Cgnon, C. Montan, R. Scopgno. Acqurng, stchng and blendng dffuse appearance attrbutes on 3D models. The Vsual Computer, 18, pp , 00. [SZE94] R. Szelsk. Image mosacng for tele-realty applcatons. TR, Dgtal Equpment Corporaton, Cambrdge, USA, [UN] UNESCO World Hertage Lst: whc.unesco.org/ [VI] Vdeo Investgator, Cogntech: [VF] Vdeo Focus, Salent Stlls: [VZG01] Vsnovcova (Nederoest), J., Zhang, L., Gruen, A. Generatng a 3D model of a Bayon tower usng nonmetrc magery. IAPRS, Vol. XXXIV, Part 5/W1, pp , 001. (c) The Eurographcs Assocaton 004.