@article{isprs-archives-XLVI-M-1-2021-739-2021,

title = {3D HOLISTIC DOCUMENTATION OF HERITAGE MONUMENTS IN RHODES},

author = {S Tapinaki and M Skamantzari and A Anastasiou and S Koutros and E Syrokou and A Georgopoulos},

url = {https://www.int-arch-photogramm-remote-sens-spatial-inf-sci.net/XLVI-M-1-2021/739/2021/},

doi = {10.5194/isprs-archives-XLVI-M-1-2021-739-2021},

year  = {2021},

date = {2021-08-28},

urldate = {2021-08-28},

journal = {The International Archives of the Photogrammetry, Remote Sensing and Spatial Information Sciences},

volume = {XLVI-M-1-2021},

pages = {739--744},

keywords = {3D reconstruction, Cultural heritage, geometric documentation, Image based modelling, laser scanning},

pubstate = {published},

tppubtype = {article}

}

@article{isprs-archives-XLIII-B2-2021-583-2021,

title = {3D AND HYPERSPECTRAL DATA INTEGRATION FOR ASSESSING MATERIAL DEGRADATION IN MEDIEVAL MASONRY HERITAGE BUILDINGS},

author = {P Kolokoussis and M Skamantzari and S Tapinaki and V Karathanassi and A Georgopoulos},

url = {https://www.int-arch-photogramm-remote-sens-spatial-inf-sci.net/XLIII-B2-2021/583/2021/},

doi = {10.5194/isprs-archives-XLIII-B2-2021-583-2021},

year  = {2021},

date = {2021-06-28},

urldate = {2021-06-28},

journal = {The International Archives of the Photogrammetry, Remote Sensing and Spatial Information Sciences},

volume = {XLIII-B2-2021},

pages = {583--590},

keywords = {3D reconstruction, Cultural heritage, Hyperspectral Images, Material Analysis, Photogrammetry},

pubstate = {published},

tppubtype = {article}

}

@article{rs13061053,

title = {Semantically Derived Geometric Constraints for MVS Reconstruction of Textureless Areas},

author = {Elisavet Konstantina Stathopoulou and Roberto Battisti and Dan Cernea and Fabio Remondino and Andreas Georgopoulos},

url = {https://www.mdpi.com/2072-4292/13/6/1053},

doi = {10.3390/rs13061053},

issn = {2072-4292},

year  = {2021},

date = {2021-03-10},

urldate = {2021-03-10},

journal = {Remote Sensing},

volume = {13},

number = {6},

abstract = {Conventional multi-view stereo (MVS) approaches based on photo-consistency measures are generally robust, yet often fail in calculating valid depth pixel estimates in low textured areas of the scene. In this study, a novel approach is proposed to tackle this challenge by leveraging semantic priors into a PatchMatch-based MVS in order to increase confidence and support depth and normal map estimation. Semantic class labels on image pixels are used to impose class-specific geometric constraints during multiview stereo, optimising the depth estimation on weakly supported, textureless areas, commonly present in urban scenarios of building facades, indoor scenes, or aerial datasets. Detecting dominant shapes, e.g., planes, with RANSAC, an adjusted cost function is introduced that combines and weighs both photometric and semantic scores propagating, thus, more accurate depth estimates. Being adaptive, it fills in apparent information gaps and smoothing local roughness in problematic regions while at the same time preserves important details. Experiments on benchmark and custom datasets demonstrate the effectiveness of the presented approach.},

keywords = {3D reconstruction, dense point cloud, depth estimation, multi view stereo (MVS), PatchMatch, Plane detection, RANSAC, semantic segmentation},

pubstate = {published},

tppubtype = {article}

}

@article{Tentoma2020,

title = {COMPARATIVE INVESTIGATION OF THE 3D REPRESENTATIONS OF THE HOLY AEDICULE OF THE TOMB OF CHRIST},

author = {Nefeli Tentoma and Andreas Georgopoulos and Grazia Tucci},

url = {https://doi.org/10.4995/Arqueologica9.2021.12153},

doi = {10.4995/Arqueologica9.2021.12153},

year  = {2020},

date = {2020-04-01},

journal = {Arqueol. 2.0 - 9th Int. Congr. 3rd GEORES - GEOmatics Preserv.},

abstract = {The significance of preservation of cultural heritage is undeniable, which is why both their geometric documentation and the creation of their digital "twins", i.e., reconstructions and replicas at any scale, are essential procedures. A special category of cultural heritage is sacred sites which combine historical, spiritual and religious values. The most sacred monument of Christianity is the Holy Aedicule covering the Tomb of Christ in the Church of the Holy Sepulchre in Jerusalem. This paper aims to investigate and compare the various three-dimensional representations of the Holy Aedicule of the Tomb of Christ, which exist both in physical and in digital form. Initially, the main structural phases of the Aedicule are presented, including its destructions and restorations. Moreover, the different categories of the three-dimensional representations of the monument are defined. With reference to the replicas, both the reasons of their construction and their list in the form of a dataset table are presented. More specifically, in the context of this research, the three-dimensional representations of the Aedicule are divided into two major categories: the replicas constructed worldwide and the geometric documentations of the monument's condition through the years. Regarding the replicas, a list of the discovered representations is created, and this database is visualized and depicted in an online web map along with essential information with the use of an open-source Geographic Information System (GIS). Based on this visualization an online web map has been created. Furthermore, the previous geometric documentations and surveys of the Holy Aedicule of the Tomb of Christ are presented. A comparison is conducted between the 3D models of the Aedicule, which were created by the University of Florence in 2007-8 and the National Technical University of Athens in 2015-17. The impact of the Holy Aedicule across the world is examined through statistics based on the type, date of construction and location of the replicas. The possible deformations of the monument's structure are detected from the assessment of the results from both the processing and the comparison of the 3D models. In conclusion, future works are suggested focusing on the discovery of the total number of replicas worldwide and the monitoring of the condition of the Aedicule.},

keywords = {3D reconstruction, Cultural heritage, digital photogrammetry, geometric documentation, online webmap, three-dimensional representations},

pubstate = {published},

tppubtype = {article}

}

@article{Kontogianni2019,

title = {EVALUATING THE EFFECT OF USING MIRRORS IN 3D RECONSTRUCTION OF SMALL ARTEFACTS},

author = {Georgia Kontogianni and M Lindstaedt and T P Kersten and Andreas Georgopoulos},

url = {https://www.int-arch-photogramm-remote-sens-spatial-inf-sci.net/XLII-2-W15/633/2019/},

doi = {10.5194/isprs-archives-XLII-2-W15-633-2019},

issn = {2194-9034},

year  = {2019},

date = {2019-08-01},

journal = {ISPRS - Int. Arch. Photogramm. Remote Sens. Spat. Inf. Sci.},

volume = {XLII-2/W15},

number = {2/W15},

pages = {633--638},

publisher = {International Society for Photogrammetry and Remote Sensing},

abstract = {Abstract. Small artefacts pose many challenges to 3D documentation techniques due to their often complex details, which are very difficult to capture completely in 3D. Small objects may also have characteristics that are not optimal for 3D documentation, e.g. glossiness, shininess, textureless surfaces, etc. Furthermore, hidden parts of the artefact cause occlusions and obstructions, which may complicate the data acquisition process, since additional images or scan data are necessary in order to compensate for these restrictions. All these aspects increase acquisition and data processing times. Currently, the two main categories of 3D documentation methods are Image Based Modelling (IBM) and Range Based Modelling (RBM). In this paper, preliminary investigations aimed at evaluating the accuracy and performance of a front surface mirror in Image Based Modelling for small artefacts are presented. These results are then compared to a reference model generated from the artefact using a structured light system.},

keywords = {3D reconstruction, front surface mirror, small artefact},

pubstate = {published},

tppubtype = {article}

}

@article{Kontogianni2017a,

title = {ENHANCING CLOSE-UP IMAGE BASED 3D DIGITISATION WITH FOCUS STACKING},

author = {Georgia Kontogianni and Regina Chliverou and A Koutsoudis and G Pavlidis and Andreas Georgopoulos},

url = {https://www.int-arch-photogramm-remote-sens-spatial-inf-sci.net/XLII-2-W5/421/2017/},

doi = {10.5194/isprs-archives-XLII-2-W5-421-2017},

issn = {2194-9034},

year  = {2017},

date = {2017-08-01},

journal = {ISPRS - Int. Arch. Photogramm. Remote Sens. Spat. Inf. Sci.},

volume = {XLII-2/W5},

pages = {421--425},

abstract = {The 3D digitisation of small artefacts is a very complicated procedure because of their complex morphological feature structures, concavities, rich decorations, high frequency of colour changes in texture, increased accuracy requirements etc. Image-based methods present a low cost, fast and effective alternative because laser scanning does not meet the accuracy requirements in general. A shallow Depth of Field (DoF) affects the image-based 3D reconstruction and especially the point matching procedure. This is visible not only in the total number of corresponding points but also in the resolution of the produced 3D model. The extension of the DoF is a very important task that should be incorporated in the data collection to attain a better quality of the image set and a better 3D model. An extension of the DoF can be achieved with many methods and especially with the use of the focus stacking technique. In this paper, the focus stacking technique was tested in a real-world experiment to digitise a museum artefact in 3D. The experiment conditions include the use of a full frame camera equipped with a normal lens (50mm), with the camera being placed close to the object. The artefact has already been digitised with a structured light system and that model served as the reference model in which 3D models were compared and the results were presented.},

keywords = {3D reconstruction, Focus Stacking, small artifacts},

pubstate = {published},

tppubtype = {article}

}

@article{Kontogianni2017b,

title = {INVESTIGATING THE EFFECT OF FOCUS STACKING ON SFM-MVS ALGORITHMS},

author = {Georgia Kontogianni and Regina Chliverou and A Koutsoudis and G Pavlidis and Andreas Georgopoulos},

url = {https://www.int-arch-photogramm-remote-sens-spatial-inf-sci.net/XLII-2-W3/385/2017/},

doi = {10.5194/isprs-archives-XLII-2-W3-385-2017},

issn = {2194-9034},

year  = {2017},

date = {2017-02-01},

journal = {ISPRS - Int. Arch. Photogramm. Remote Sens. Spat. Inf. Sci.},

volume = {XLII-2/W3},

pages = {385--389},

abstract = {The Depth of Field (DoF) is a vital factor in photogrammetric applications. Its effect is in most cases pretty obvious especially when capturing small artefacts. It is very important to observe its behaviour as it affects the ability to capture all the details of an object. Focus stacking is a technique in computational photography, in which a set of images focused on different planes with limited DoF are combined in order to considerably extend the DoF. Today, there is a number of focus stacking methods that can be applied in order to produce a full-focus image. In this paper, we investigate the application and effects of focus stacking on SfM-MVS 3D reconstruction. Specifically, our experiment involves the 3D reconstruction of a selected artefact using both traditional all-focus photography and focus stacking. The artefact has already been digitised with a high accuracy and resolution structured light 3D scanner, and that 3D model served as the reference model, with which SfM models were compared. We discuss on these fist results and present some preliminary assessment on the application of focus stacking for the SfM-MVS-based 3D reconstruction.},

keywords = {3D reconstruction, Focus Stacking, SfM-MVS},

pubstate = {published},

tppubtype = {article}

}