Littérature scientifique sur le sujet « Photomodeling »

Abstract. This paper presents some experiments on the use of an alternative technique, Nerf, based on artificial intelligence, which can be used in the survey of architectural structures or parts of them. The Nvidia video cards supported by the new RTX architectures are now able to manage an enormous amount of data both in the calculation of lighting and the rendering of digital shaders, and in the management of the number of polygons that can be displayed in real time in the scene. The support of artificial intelligence has further improved the three-dimensional digitization process in order to support the hardware power of algorithms that use neural networks to optimize and reduce calculation times, improving various aspects of the graphics and also of the digital representation, also influencing the representation on “image based” 3D acquisition methods, currently the most used low-cost systems in the photomodeling of objects or three-dimensional scenes. At the current state of the art, many commercial companies and research organizations, first Nvidia with its Instant Nerf, are betting on algorithms based on the Neural Radiance Field. The paper highlights the criticalities of this new system and shows the discrete results and the expandable research scenarios that can involve the impossible survey with photomodeling methodology related to works of art or architecture, due to the intrinsic nature of the materials that they compose them or because it is impossible or very difficult to photograph them.

In recent years, an increase in international investment in hardware and software technology to support programs that adopt algorithms for photomodeling or data management from laser scanners significantly reduced the costs of operations in support of Augmented Reality and Virtual Reality, designed to generate real-time explorable digital environments integrated to virtual stereoscopic headset. The research analyzes transversal methodologies related to the acquisition of these technologies in order to intervene directly on the phenomenon of acquiring the current VR tools within a specific workflow, in light of any issues related to the intensive use of such devices , outlining a quick overview of the possible "virtual migration" phenomenon, assuming a possible integration with the new internet hyper-speed systems, capable of triggering a massive cyberspace colonization process that paradoxically would also affect the everyday life and more in general, on human space perception. The contribution aims at analyzing the application systems used for low cost 3d photogrammetry by means of a precise pipeline, clarifying how a 3d model is generated, automatically retopologized, textured by color painting or photo-cloning techniques, and optimized for parametric insertion on virtual exploration platforms. Workflow analysis will follow some case studies related to photomodeling, digital retopology and "virtual 3d transfer" of some small archaeological artifacts and an architectural compartment corresponding to the pronaus of Aurum, a building designed in the 1940s by Michelucci. All operations will be conducted on cheap or free licensed software that today offer almost the same performance as their paid counterparts, progressively improving in the data processing speed and management.

This research deals with an efficient and low cost methodology to obtain a metric and photorealstic survey of a complex architecture. Photomodeling is an already tested interactive approach to produce a detailed and quick 3D model reconstruction. Photomodeling goes along with the creation of a rough surface over which oriented images can be back-projected in real time. Lastly the model can be enhanced checking the coincidence between the surface and the projected texture. The challenge of this research is to combine the advantages of two technologies already set up and used in many projects: spherical photogrammetry (Fangi, 2007,2008,2009,2010) and structure for motion (Photosynth web service and Bundler + CMVS2 + PMVS2). The input images are taken from the same points of view to form the set of panoramic photos paying attention to use well-suited projections: equirectangular for spherical photogrammetry and rectilinear for Photosynth web service. The performance of the spherical photogrammetry is already known in terms of its metric accuracy and acquisition quickness but time is required in the restitution step because of the manual homologous point recognition from different panoramas. In Photosynth instead the restitution is quick and automated: the provided point clouds are useful benchmarks to start with the model reconstruction even if lacking in details and scale. The proposed workflow needs of ad-hoc tools to capture high resolution rectilinear panoramic images and visualize Photosynth point clouds and orientation camera parameters. All of them are developed in VVVV programming environment. 3DStudio Max environment is then chosen because of its performance in terms of interactive modeling, UV mapping parameters handling and real time visualization of projected texture on the model surface. Experimental results show how is possible to obtain a 3D photorealistic model using the scale of the spherical photogrammetry restitution to orient web provided point clouds. Moreover the proposed research highlights how is possible to speed up the model reconstruction without losing metric and photometric accuracy. In the same time, using the same panorama dataset, it picks out a useful chance to compare the orientations coming from the two mentioned technologies (Spherical Photogrammetry and Structure for Motion).

Abstract. The aim of the proposal is to illustrate how expeditious procedures of urban survey carried out through photomodeling can be the most suitable representation tool in combination with an expeditious procedure for assessing the seismic vulnerability of the historic building heritage in Italian city centres. For some years, in fact, the research group is developing a protocol for the rapid assessment of the seismic vulnerability of masonry aggregate buildings in Italian historic centres.The protocol is based on the determination of synthetic indicators providing a preventive quantification of the possible earthquake damage. This evaluation procedure is oriented to prevent and reduce the current vulnerability, aiming at the conservation and preservation of the historic building heritage. The synthetic indicators are defined by identifying expeditious evaluation procedures based on the typical evolutionary processes suffered by each aggregate in its planimetric and height development, on the construction techniques and on the design concepts used in the local area; these aspects are directly correlated to failure modes.The application of the entire process (starting from the rapid survey phases up to the final restitution of the seismic vulnerability assessment results) is illustrated for the historic centre of Imola. The ancient nucleus of this city constitutes an excellent example, as it is clearly representative of the Emilian historical architecture both for the processes of formation and transformation of the inhabited area, both for what concerns the constructive characterization deriving from the local building traditions.

Photomodelling is a new and fast solution for 3D modelling, based on the same principles of photogrammetry. The comparison between photomodelling and the metrological technique of structured light 3D scanning, provided by the Creaform Go Scan 50 with metrological certification, is the aim of this paper, defining performances and verifying the potential of this innovative, simple and economical technique.

Abstract. In accordance with the “Declaration of Rome on architectural survey”, we can affirm that recording and interpretation of colour information in photographic surveying, in photogrammetric surveying and in photomodelling requires careful planning of Colour Imaging processes. Information acquired by an optical sensor is influenced not just by the actual photographed scene, but also by the spectral sensitivity of the sensor. We have adopted, from the field of Cultural Heritage, a method of colourimetric calibration for digital photographs and have proposed some adjustments to finalise this process for the purposes of Architectural Survey. With the use of a colourimetric target and a non-linear transformation algorithm, our Colour Imaging method statistically reconstructs colours conventionally unrecordable by a commercial camera. In addition, this method reconstructs colours as if the photographed object were exposed to a standard illuminant, assessing a colour error parameter value for each photo. By including the colourimetric target in every shot and by applying the calibration algorithm to all photographs taken, the process correlates all data sets to a single standard illuminant: regarding photomodelling, this leads to a more uniform and detailed representation of the surfaces of virtual models. We present two successful examples of application: one focused on a design object with physioplastic decoration and another regarding a circular fountain in a historic villa.

Abstract. Thanks to the development of new Cuda technologies applied to graphics cards and to a more accessible and growing use by professionals in various commercial, artistic and research sectors, the latest generation digital instruments have implemented new methods of photogrammetric surveying and remote sensing, progressively reducing the cost of the instruments and that related to the application development of the different SfM algorithms, now widely used also in numerous open source software. The research presented in the article compares two of the most recently used free programs with the most satisfactory results in the field of 3D photogrammetric survey and photomodelling: Meshroom, developed by AliceVision and Regard3D, an open source software, compiled in 2015 by the Swiss IT engineer freelance Roman Hiestand. The test case study will concern the photo-modelling, through the free tools previously discussed, of medium size complex decorative details, one of the monumental gates of the ancient Roman city of Sepino, an archaeological site in Molise (IT) located at the foot of the Matese and extending over the Tammaro valley, so as to be able to fully test the capture characteristics and the trend and structure of the pipeline of the two software examined.

Abstract. The promotion and dissemination of architectural heritage for cultural enhancement and touristic enjoyment are increasingly focused on innovative ICTs, including 3D Geographic Information Systems, photorealistic models and scenes, and VR/AR immersive digital environments, which enable the interaction of visitors with a variety of informational contents, both educational and specialist. Within the above-mentioned framework, this paper will firstly outline the general objectives of the project “3D-IMP-ACT”, which has been funded under the international cooperation programme IPA CBC Interreg Italy-Albania-Montenegro. In this research, some ICT tools are tested and validated to create “virtual networks” of international ancient architectures and sites, based on the identification of “physical networks” of common historic, environmental and technical characteristics and infrastructural connections, in order to address coordinated strategies and transversal policies for development and management. Then, the paper will describe and discuss some results from the design and implementation of the project WebGIS system, which integrates virtual tours of 360° panoramas, 3D models from photomodelling of pictures taken by drones, multimedia contents, and 2D/3D historic evolution schemes within a single platform, where the users are supported in recognizing and exploring the tangible and intangible correspondences among the project pilot-cases. In conclusion, some remarks will be proposed on the potential benefits of the platform as an expert system which supports the technical assessment and control of architectural heritage toward maintenance, refurbishment and conservation.

Abstract/ITA La tesi di dottorato proposta vuole esplicitamente affrontare il tema delle metodologie di rilievo e rappresentazione per la documentazione e l’analisi dell’architettura in legno. La ricerca è stata condotta non solo affrontando il tematica da un punto di vista pratico o semplicemente operativo, ma ha voluto approfondire le attività di ricognizione e studio per la comprensione del luogo, del genius loci, delle tradizioni e della vita di questi contesti. La ricerca proposta vuole esplicitamente affrontare la trattazione del tema dell’architettura in legno con un duplice approccio: di tipo teorico e di tipo operativo metodologico, per poter definire e sviluppare sistemi rappresentativi adeguati allo studio delle opere lignee. La tesi è composta da tre parti, più una quarta dedicata alle conclusioni. La prima affronta le tematiche relative al costruire in legno considerando il tema da un punto di vista teorico, relazionato al dibattito di natura filosofica sul concetto di ”capanna primitiva”, offrendo una panoramica sulle principali teorie sostenute da personaggi illustri come Vitruvio, Laugier, Semper e Rykwert fino ad arrivare ai nostri giorni e riguardando l’architettura del legno da un punto di vista tecnologico, legato alla definizione delle caratteristiche generali del materiale e all’individuazione delle principali tecniche costruttive. In questa parte sono presentate le diverse tradizioni architettoniche presenti nei paesi del Nord Europa, proponendo un panorama di esempi e documentazioni di architetture in legno. La seconda parte è dedicata nello specifico all’area di studio della Carelia (Federazione Russa), con un approccio metodologioco che va dal generale (inquadramento territoriale, sociale e paesaggistico) al particolare (introduzione alle metodologie operative di studio e presentazione dei casi analizzati). Nella terza parte vengono illustrate le diverse metodologie di rilevamento e le procedure necessarie per svolgere le diverse indagini, presentando i villaggi careliani scelti come aree campione per lo sviluppo delle metodologie di analisi e i risultati ottenuti su ciascun caso studio in base alle finalità descrittive stabilite. La quarta parte, dedicata alle conclusioni, vuole fondere gli aspetti teorici approfonditi con i risultati pratici e tecnici ottenuti dalle attività di rilievo e rappresentazione; vengono tracciate le linee guida per lo sviluppo di protocolli metodologici atti alla documentazione, analisi, rappresentazione e gestione sul patrimonio territoriale e architettonico della Carelia. Il principale contributo che questa ricerca vuole offrire è lo sviluppo e l’elaborazione di procedure scientifiche, tecniche e operative, per la documentazione di strutture in legno, maturate grazie alle esperienze condotte sui villaggi lignei tradizionali in Carelia all’interno del progetto europeo Wooden Architecture. La ricerca pone le basi per determinare le modalità di esecuzione dell’indagine, individuando gli aspetti fondamentali per l’analisi e per il censimento di sistemi complessi. E’ stato elaborato un confronto tra modelli culturali che ha permesso di considerare gli elementi principali del rilievo, della rappresentazione dell’architettura e dell’ambiente in un percorso dove la ricerca teorica abbraccia la sperimentazione pratica e viceversa con l’intento di stabilire le linee guida fondamentali per il rilievo dell’architettura in legno. Abstract/ENG The doctoral thesis proposal originally wanted to address the issues of how-to-do research on wooden buildings, a comparison and analysis not only practical matters or simply linked to detection techniques, but also going deeper to know the place, in the sense of understanding of genius loci, the traditions, the life that exists around and inside these contexts. The thesis consists of two main section: a theoretical and a practical approach, their interaction and meeting with the practice. The index structure of the thesis is mainly composed of three parts, plus a fourth part devoted to conclusions. The first part deals with the general characteristics and aspects related to wooden architecture. In Chapter 1 deals with the theoretical discourse of the concept of “primitive hut” offering a wide scenery of the main theories or historical thesis supported by the great personalities of architecture, from Vitruvius, Laugier, Semper Ryckwert until a reflection on modern age. Chapter two, however, approaches the topic from a technological point of view and more related to the investigation on the wooden material, its characteristics from a static point of view and structural, on the positive and negative aspects related to its use within construction. The third chapter is devoted to the illustration of the different traditions of wooden architecture in several European countries, offering a wide panorama of cases and examples of architecture and building techniques peculiar to different geographical areas. The second part, aims to introduce the research area, entering into specific in the context of architecture in Northern Europe, particularly in Karelia. Starting from the description of the aspects of a general nature, landscape and environment, you get to have a detailed knowledge about the architecture of wood in this particular context. The third part is the most scientific and technical, which are addressed in the different survey methods of detection, direct, indirect, laser scanners, photo modeling, illustrating the specific procedures necessary to carry out this type of investigation and presenting the results according to stated purposes. The discussion of these topics ranges from technical explanations and case studies to practical matters in which it is possible to have a direct feedback and interaction between practical and theoretical approaches. The fourth part, combines and blends the more theoretical aspects of the opening chapters with the practical part of the subsequent chapters. Drawn from the global experience there are offered excellent considerations which are made of the theoretical study and archive research and practical experience of evaluation and validation of the research objects. Research-theory-practice triangle always offers new insights into the world of wooden architecture. The main, important contribution that this research has investigated is the development and elaboration of scientific-technical and operational protocols and tools for the documentation of wooden structures. Understanding how the survey should be performed, locating the primary aspects fundamental to the analysis at the moment when one is confronted with wooden artifacts. To develop the census system, filing with which to define the descriptions useful for the technician who may devote attention to architecture. When this part is well taken care of, also the value assessment of wooden architecture becomes easier.

The constant development and improvement of laser scanning instruments together with the digital rebirth of photogrammetry (photomodelling) has triggered the operative and methodological evolution that in many aspects has already facilitated the acquisition phase, especially referring to the time required for the procedure. The present paper, however, investigates the methodological changes occurred especially in the last decade concerning surveying and its representation. We shall describe the peculiarities and articulations of these methods aiming at pointing out some conceptual issues involving measurement, interpretation and representation. The final objective is to construct an “operative critical method” which seems indispensable to standardize and regulate the procedures of data collection, elaboration and representation of architectural artifact providing results more objective and reliable: in other words more scientific.