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Left: HCU graphical user interface (GUI) for the automatic workflow of Bundler/PMVS2; right: GUI for accelerated data processing with VisualSFM.
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Constant improvements in the performance of internet and computer technologies combined with rapid advancements in computer vision algorithms now make it possible to efficiently and flexibly reconstruct the 3D geometry of objects. Objects of different sizes can be modelled using image sequences from commercial digital cameras that are processed by...
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... gener- ate 3D models that are quite attractive visually when the archaeological objects are small and relatively rotund. A moai at the volcano crater Poike on Easter Island (Chile) was acquired in 27 surrounding photos with a Nikon D70 (Nikkor zoom lens with 35 mm). The result from 123D Catch Beta provided an almost- complete, textured 3D model ( Fig. 10) with 169,131 triangles (from 85,092 points) while with Bundler/PMVS2 despite measurement of nearly 630,000 points, some gaps at the neck and at the bottom of the figure were ...
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... to 2 mm grid spacing, and from 123D Catch Beta with the reference data was carried out in Geomag- ic after ICP registration of each model to the eschweizerbart_xxx successfully generated using 123D Catch Beta, because both laser scanner IMAGER 5006i and Bundler/PMVS2 could only meas- ure very noisy point clouds with each includ- ing some gaps (Fig. 11). For measurements A geometrical accuracy analysis of this data could not be carried out due to the absence of reference ...
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... 3D model of the rear of a moai eye, carved from Obsidian stone, could only be for the upper and lower object part (Fig. 12). Using the measuring scale (10 cm), which was additionally placed into object space for the photographs, the scaling of the two datasets could be carried out. Firstly, the upper and lower 3D point clouds were registered using ICP algorithm. Secondly the 3D model was generated using the common point cloud with 0.5 mm grid spacing. ...
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... clouds were registered using ICP algorithm. Secondly the 3D model was generated using the common point cloud with 0.5 mm grid spacing. Finally, a 3D compari- son between model and reference was comput- ed in Geomagic. This showed that differences larger than 1 mm only occurred at the bound- ary regions and in those areas with large cur- vatures (Fig. 12). These differences can be ex- plained by the higher resolution of the image- ry compared to the more smoothed scan data. The average deviation between image-based and range-based 3D model is 1 mm, while the standard deviation is 1.4 mm (Tab. ...
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... The image data was pro- cessed with VisualSFM using the full image resolution of the photographs for each image block producing two point clouds (595,933 points in total with grid spacing of 1 mm). Af- ter registration of the two point clouds with ICP algorithm a combined meshed 3D mod- el (approximately 1,135,284 triangles in total) was computed (Fig. 13 left in each ...
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... from the Pentax Optio X (2560 x 1920 pixel) with 10 mm focal length, b) ten photos from a Nikon D70 (3008 x 2000 pixel) with a focal length of approx. 40 mm, and c) eleven photos from a Nikon D80 (3872 x 2592 pixel) with a focal length of 50 mm. The textured 3D model of the moai eye gener- ated with 123D Catch Beta consists of 291,613 triangles (Fig. 11, right), while in total only 214,940 points were measured with Bundler/ PMVS2 and only 95,820 points were scanned with the IMAGER 5006i. Although 3D com- parison with reference data could not be con- ducted for accuracy analysis, subjective com- parison of the provided 3D model suggests that it corresponds very well to the original. The model ...
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... the next two examples (pottery/ceramic and architectural fragment from Yeha/Ethio- pia) reference data were available. The pottery (ceramic(s)) was acquired by camera and la- ser scanner in order to compare image-based and range-based object recording. The pottery (Fig. 12) was photographed in the upper part with 50 photos and in the lower part with 30 photos using a Nikon D40 (Nikkor zoom lens, focal length 34 mm). With the terrestrial la- ser scanner IMAGER 5006h nine scans were required to achieve complete recording of the object. The triangle meshing of the pottery (approx. 160,590 triangles) was ...
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... 160,590 triangles) was computed us- ing the registered scans in Geomagic. The im- age data was processed with Bundler/PMVS2 using a reduced image resolution of 2400 pix- els, i.e. a point cloud was separately generated eschweizerbart_xxx performed in Geomagic producing the results of the front and rear sides of the fragment pre- sented in Fig. 14. Differences from the image- based data to the reference, which are below 1 mm in the average (Tab. 2), are depicted in green. This comparison demonstrated that the dataset corresponds most closely to the result from laser scanning in the range of ±1 mm. Since the image data obviously supplied more details with a higher resolution than ...
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... data to the reference, which are below 1 mm in the average (Tab. 2), are depicted in green. This comparison demonstrated that the dataset corresponds most closely to the result from laser scanning in the range of ±1 mm. Since the image data obviously supplied more details with a higher resolution than the smoothed scanning data in this case study (Fig. 14), these comparisons should primarily raw data at 10 m distance is 0.5 mm for a re- flectivity of 14% (black), 0.4 mm for a reflec- tivity of 37% (dark grey), and 0.3 mm for a re- flectivity of 80% (white). The registered point cloud (2,072,781 points) was filtered and re- duced in Geomagic to a regular point distance of 2 mm, resulting ...
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... data at 10 m distance is 0.5 mm for a re- flectivity of 14% (black), 0.4 mm for a reflec- tivity of 37% (dark grey), and 0.3 mm for a re- flectivity of 80% (white). The registered point cloud (2,072,781 points) was filtered and re- duced in Geomagic to a regular point distance of 2 mm, resulting in a mesh of approximate- ly 1,120,580 triangles (Fig. 13). First the scan data was slightly smoothed using a noise filter. After ICP registration of the meshed model from image-based data with the meshed mod- el from laser scanning a 3D comparison was ...
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The documentation of cultural heritage is an essential part of appropriate care of historical monuments, representing a part of our history. At present, it represents the current issue, for which considerable funds are being spent, as well as for the documentation of immovable historical monuments in a form of castle ruins, among the others. Non-co...
Citations
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... After the initial point cloud was optimized, a dense point cloud was generated and used to construct a continuous mesh surface that was then triangulated and rendered with the sequential images to create textured 3D digital surface models representing the coral assemblage at Wai'ōpae. The 84 coordinates were annotated onto the 3D model in GeoMagic 3D annotation software that represented the actual sampling sites where tissue samples were taken from each coral [37]. Coordinates were matched with each sample file from LC-MS/MS and 16S OTU feature tables. ...
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... For the second requirement, 3D reconstruction of the parts unavailable for scanning from preserved traditional 2D archiving materials such as manual drawings, photographs, and documents is needed. Many studies use image-based methods to digitize CH using multiple photos from different directions [13][14][15]. However, in many cases, no good photos for such methods remain. ...
... For the destroyed or inaccessible parts of CH sites, 3D reconstruction from previously preserved 2D archiving materials is widely studied. Many works [8,13,14,26,27] have created 3D models of CH sites from historical/open-source photographs and videos. Bruha et al. [28] combined diverse 3D data sources as well as referential terrain models to reconstruct the vanished medieval town of Sekanka and the surrounding landscape. ...
... Remote Sens. 2021,13, 5024 ...
The preservation and analysis of tangible cultural heritage sites have attracted enormous interest worldwide. Recently, establishing three-dimensional (3D) digital archives has emerged as a critical strategy for the permanent preservation and digital analysis of cultural sites. For extant parts of cultural sites, 3D scanning is widely used for efficient and accurate digitization. However, in many historical sites, many parts that have been damaged or lost by natural or artificial disasters are unavailable for 3D scanning. The remaining available data sources for these destroyed parts are photos, computer-aided design (CAD) drawings, written descriptions, etc. In this paper, we achieve an integrated digital archive of a UNESCO World Heritage site, namely, the Borobudur temple, in which buried reliefs and internal foundations are not available for 3D scanning. We introduce a digitizing framework to integrate three different kinds of data sources and to create a unified point-cloud-type digital archive. This point-based integration enables us to digitally record the entire 3D structure of the target cultural heritage site. Then, the whole site is visualized by stochastic point-based rendering (SPBR) precisely and comprehensibly. The proposed framework is widely applicable to other large-scale cultural sites.
... With the advancement of image processing, photogrammetry has become a relatively easy and inexpensive method for 3D reconstruction of cultural heritage (Nocerino et al. 2017). Consequently, there is a tendency to develop software solutions, available through free, commercial and open-source programs, that generate reliable 3D solutions in docu-menting cultural heritage (Bartoš et al. 2014;Kersten and Lindstaedt 2012;Gonizzi-Barsanti et al. 2012), providing users with different levels of automation, visualization and integration with other technologies, such as virtual reality . Today, photogrammetry software allows image processing to be performed by non-professional users by having only an integrated camera on their mo-bile devices (Tanskanen et al. 2013). ...
Recently, photogrammetry has become a relatively easy and low-cost method for cultural heritage 3D reconstruction. Plenty of free and open-source photogrammetry programs have been developed, but not all of them provide an adequate solution for the 3D reconstruction of cultural heritage. In this research, an overview of the state-of-the-art open-source photogrammetry programs was done. In order to investigate whether among the open-source software packages there is an adequate alternative to the commercial software for the purpose of cultural heritage 3D reconstruction, the open-source software-AliceVision Meshroom was compared to the most commonly used commercial software Agisoft Metashape. The programs were compared on the examples of cultural heritage objects and according to the predefined criteria that are important for achieving detailed and accurate 3D reconstruction. The results of testing and comparing the 3D reconstructions obtained using Meshroom and Metashape were illustrated and explained through two case studies of antic objects of cultural heritage, characterized by similar materialization, but different geometric shapes.
... In addition, most SfM programs allow for dense matching, meshing and orthophoto generation, which is a standard photogrammetric post-processing after bundle adjustment. SfM integrates a number of established methods, developed for non-targeted image data sets, to reconstruct a three-dimension structure or object in digital space from the motion of a camera (Kersten and Lindstaedt 2012;Luhmann et al. 2019). ...
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