CONVENTIONAL OR AUTOMATED PHOTOGRAMMETRY FOR CULTURAL HERITAGE DOCUMENTATION?

During the past 15 years photogrammetric practice has experienced an unprecedented change by the influence of computer vision algorithms, which support an almost completely automated processing. It is widely acknowledged that this fact has “democratized” Photogrammetry a lot, in the sense that it has become almost everyone’s tool. However, this radical change has been met by scepticism by traditional photogrammetrists, who claim that such tools may lead to geometrically wrong and inaccurate results if not accompanied by thorough projection and error checks and evaluation of the correctness of results.In this paper, the two approaches are briefly described on the basis of the geometric documentation of a cultural heritage funerary monument situated in the archaeological site of Messini in Southern Greece. An effort is made for highlighting the obvious advantages of each approach but also indicating their disadvantages. Applications, subject to different requirements and processing procedures are identified, rationalizing that conventional photogrammetric procedures still cannot be easily replaced.</p

3D DOCUMENTATION AND VIRTUAL ARCHAEOLOGICAL RESTORATION OF MACEDONIAN TOMBS

Archaeology as a science is based on finding and displaying the remains of the past. In recent years, with the progress of technology, the science of archeology has been expanding and evolving. Three-dimensional digitization has become an integral part of the archiving, documentation and restoration effort of cultural heritage, offering important benefits in studies for reconstruction and restoration tasks of architectural creations, archaeological sites, historic monuments and objects of art in general. The three-dimensional models are now available for many applications. In this paper such 3D models of two prominent Macedonian tombs in Northern Greece were exploited for their virtual restoration. Virtual restoration of monuments is of special importance to archaeological research, as it provides the necessary tools to investigate alternative solutions to the serious issue of archaeological restoration. These solutions do not interfere with the real monument, thus respecting its value and the international conventions. Digital 3D models have begun to be more beneficial in a science such as archaeology as they offer easy access to both archaeological and geometric information to a wider audience as well as a high degree of interaction possibilities with the user

3D VISUALIZATION FOR VIRTUAL MUSEUM DEVELOPMENT

The interest in the development of virtual museums is nowadays rising rapidly. During the last decades there have been numerous efforts concerning the 3D digitization of cultural heritage and the development of virtual museums, digital libraries and serious games. The realistic result has always been the main concern and a real challenge when it comes to 3D modelling of monuments, artifacts and especially sculptures. This paper implements, investigates and evaluates the results of the photogrammetric methods and 3D surveys that were used for the development of a virtual museum. Moreover, the decisions, the actions, the methodology and the main elements that this kind of application should include and take into consideration are described and analysed. It is believed that the outcomes of this application will be useful to researchers who are planning to develop and further improve the attempts made on virtual museums and mass production of 3D models

UNDERWATER PHOTOGRAMMETRY IN VERY SHALLOW WATERS: MAIN CHALLENGES AND CAUSTICS EFFECT REMOVAL

In this paper, main challenges of underwater photogrammetry in shallow waters are described and analysed. The very short camera to object distance in such cases, as well as buoyancy issues, wave effects and turbidity of the waters are challenges to be resolved. Additionally, the major challenge of all, caustics, is addressed by a new approach for caustics removal (Forbes et al., 2018) which is applied in order to investigate its performance in terms of SfM-MVS and 3D reconstruction results. In the proposed approach the complex problem of removing caustics effects is addressed by classifying and then removing them from the images. We propose and test a novel solution based on two small and easily trainable Convolutional Neural Networks (CNNs). Real ground truth for caustics is not easily available. We show how a small set of synthetic data can be used to train the network and later transfer the learning to real data with robustness to intra-class variation. The proposed solution results in caustic-free images which can be further used for other tasks as may be needed

UNDERWATER PHOTOGRAMMETRY IN VERY SHALLOW WATERS: MAIN CHALLENGES AND CAUSTICS EFFECT REMOVAL

In this paper, main challenges of underwater photogrammetry in shallow waters are described and analysed. The very short camera to object distance in such cases, as well as buoyancy issues, wave effects and turbidity of the waters are challenges to be resolved. Additionally, the major challenge of all, caustics, is addressed by a new approach for caustics removal (Forbes et al., 2018) which is applied in order to investigate its performance in terms of SfM-MVS and 3D reconstruction results. In the proposed approach the complex problem of removing caustics effects is addressed by classifying and then removing them from the images. We propose and test a novel solution based on two small and easily trainable Convolutional Neural Networks (CNNs). Real ground truth for caustics is not easily available. We show how a small set of synthetic data can be used to train the network and later transfer the learning to real data with robustness to intra-class variation. The proposed solution results in caustic-free images which can be further used for other tasks as may be needed

Virtual anatomy museum: Facilitating public engagement through an interactive application

Digitisation has become a common practice in the preservation of museum collections. Recent development of photogrammetry techniques allows for more accessible acquisition of three-dimensional (3D) models that serve as accurate representations of their originals. One of the potential applications of this is presenting digital collections as virtual museums to engage the public. Medical museums, particularly, would benefit from digitisation of their collections as many of them are closed to the public.The aim of this project was to design and create an interactive virtual museum which would represent the Anatomy Museum at the University of Glasgow with key specimens digitised using photogrammetry techniques. Members of the general public (25 participants) were asked to evaluate the usability and effectiveness of the interactive application by completing questionnaires.A process to digitise anatomical specimens using photogrammetry and convert them into game-ready 3D models was developed. The results demonstrated successful generation of 3D models of specimens preserved using different techniques, including specimens preserved in fluid and glass jars. User tests and evaluation of the application by members of the general public were positive, with participants agreeing that they would now consider visiting the real museum after using the virtual version