基于高精度三维模型的大型石窟类文物等比例复制

文物复制是文化遗产(尤其是超大型不可移动文物)保护、传承和发展的重要基础,三维激光扫描、3D打印等新兴技术的发展为文物复制提供了新的思路。本研究以云冈第18窟为研究对象,首次探索并建立了基于高精度三维模型的超大型文物等比例高保真复制技术体系,主要包括:高保真数据获取、三维重建、复制模型分块、打印与安装、高保真涂料喷绘。该方法已应用在云冈第18窟等大型石窟类文物的等比例高保真复制工程。结果表明,本方法能够实现大型石窟类文物的高保真等比例复制,复制成果满足可移动的实际需求。该方法可为类似的文化遗产保护工作提供一定的借鉴和指导。     

Laser scanning for conservation and research of African cultural heritage sites: the case study of Wonderwerk Cave,South Africa

The ‘African Cultural Heritage and Landscape Database’ project, initiated and directed by the senior author and administered by Aluka (www.aluka.org), is aimed at the creation of a digital library of spatial and non-spatial materials relating to cultural heritage sites in Africa. The archaeological site of Wonderwerk Cave (South Africa) is one of the 19 sites documented to date using laser scanning, conventional survey, digital photogrammetry and 3D modelling. To date, it is one of the few archaeological caves worldwide to be fully scanned. This paper explores the different uses to which the spatial data derived from this cave have been, or will be, put – for historical and educational purposes, scientific research and site conservation and development.     

试论数据采集与虚拟修复在大足石刻修复中的应用

文物作为一种不可再生的宝贵资源,其本体上的保护修复工作均需慎之又慎,需遵循国际上规定的“最小干预”及“可逆性”基本原则.为此,虚拟修复成为对文物动手修复时的重要辅助手段.然而,多数文物具有复杂立体结构和色彩,传统的虚拟修复技术难以实现逼真效果.三维激光扫描是近年来飞跃发展的一项高新测绘与信息技术,具有无损、空间精度高、速度快等突出优势,在文物数字留存及相关保护应用中发挥了重要作用.三维激光扫描技术与高清摄影技术相结合,为文物的虚拟修复带来新的契机.本文结合文物虚拟修复基本需求分析,提出了基于三维激光扫描技术的文物虚拟修复关键技术与工作流程,并以国家一号石质文物保护工程——大足石刻宝顶山千手观音造像的保护修复为例,进行了应用实践,综合历史资料和现有数据的分析,实现了三维形态及色彩的虚拟修复.结果表明,基于三维扫描的虚拟修复能够提供更为逼真的三维虚拟修复模型,供修复专家研究参考.     

三维激光扫描在文物考古中应用述评

对文物和遗址遗存进行精确描述和测绘一直是文物保护和考古发掘工作中的一个重要内容。相较于传统测绘方法,三维激光扫描具有快速、准确、无需接触文物表面等优势,已被广泛采用于文物保护和考古发掘工作中。本文对三维激光扫描的原理和工作流程进行简要介绍,并对其近期在文物保护和考古工作中的应用情况做出综述和评论。     

多种科技方法在古月桥勘察修缮设计中的应用

建于南宋嘉定六年(公元1213年),位于浙江省义乌市的古月桥是折边拱桥这种桥梁发展过渡形式中不可多见的典型实证,具有极高的历史、科学、艺术、文化和社会价值。为了明确古月桥目前的状态,分析其主要威胁及病害原因,判断结构稳定性,进而制定有针对性的修缮方案,采用多种科技方法对古月桥进行了勘察和综合判断。面对桥身残破的现状,工作组采取了三维激光扫描、微观实验、结构分析等多种科技方法综合勘察,不仅较为清晰的地了解了古月桥的病害威胁,也分析了其背后致因及相互之间的联系;最终对古月桥稳定性及保存状况做出了综合判断。上述多种方法的应用,不仅相互印证了勘察结论,也为后续保护工作提供了重要的依据。     

山西省万荣县寿圣寺塔的多视角影像三维重建

为了制定山西省万荣县寿圣寺塔的保护规划方案,需制作具有真实纹理的三维模型,但砖塔等大型不可移动文物的三维重建难度很大,制作成本一直很高。为此,本研究运用无人机拍摄和地面拍摄多视角影像的技术,制作寿圣寺塔的三维模型,生成各个立面的正射影像图,量算砖塔的高度、宽度等尺寸数据,为这类文物的三维重建提供一种新的技术和方法。     

Performance evaluation of a multi-image 3D reconstruction software on a low-feature artefact

Nowadays, multi-image 3D reconstruction is an active research field and a number of commercial and free software tools have been already made available to the public. These provide methods for the 3D reconstruction of real world objects by matching feature points and retrieving depth information from a set of unordered digital images. This is achieved by exploiting computer vision algorithms such as Structure-From-Motion (SFM) and Dense Multi-View 3D Reconstruction (DMVR). In this work, we evaluate the performance of a low-cost commercial SFM–DMVR software by digitising a Cycladic woman figurine. Although the surface properties of the specific artefact are considered 3D laser scanner friendly, its almost featureless white-grey surface composes a challenging digitisation candidate for image based methodologies as no strong feature points are available. We quantify the quality of the 3D data produced by the SFM–DMVR software in relation to the data produced by a high accuracy 3D laser scanner in terms of surface deviation and topological errors. We question the applicability and efficiency of two digitisation pipelines (SFM–DMVR and laser scanner) in relation to hardware requirements, background knowledge and man-hours. This is achieved by producing a complete 3D digital replica of the Cycladic artefact by following both pipelines.     

Combining photogrammetry and laser scanning for the recording and modelling of the Late Intermediate Period site of Pinchango Alto,Palpa, Peru

This paper describes the 3D modelling of Pinchango Alto, Peru, based on a combination of image and range data. Digital photogrammetry and laser scanning allow archaeological sites to be recorded efficiently and in detail even under unfavourable conditions. In 2004 we documented Pinchango Alto, a typical site of the hitherto poorly studied Late Intermediate Period on the south coast of Peru, with the aim of conducting spatial archaeological analyses at different scales. The combined use of a mini helicopter and a terrestrial laser scanner, both equipped with a camera, allowed a fast yet accurate recording of the site and its stone architecture. In this paper we describe the research background, the 3D modelling based on different image and range data sets, and the resulting products that will serve as a basis for archaeological analysis.     

From Hand Survey to 3D Laser Scanning: A Discussion for Non-Technical Users of Heritage Documentation

Abstract

Digital technology has changed our approaches to cultural heritage documentation radically and promises to continue to bring rapid changes. Photographic and non-photographic (graphic) documentation tools are merging in one process, in which digital photographic technology is the main base. Due to digital technology, there is an increasing gap between specialist technicians and non-technical users involved in heritage documentation. 3D approaches are still not popular among users in cultural heritage. However, in order to build a bridge between the specialist and non-technical users, a dialogue between them needs to be developed, not only to discuss issues of data precision and 3D accuracy, but also visualization production systems, which can now easily be achieved by modern digital photographic technology.

This paper presents a comparative evaluation and synthesis of cultural heritage documentation methods and survey techniques currently available, focusing on the needs and requirements of non-technical users of heritage documentation. It attempts to clarify some new aspects in cultural heritage documentation and to assess the impact of current technology. The paper undertakes a comparative evaluation of the potential application of digital methods in documentation — and examines issues such as quality, accuracy, time, costs and specific skills required — from pre-electronic techniques (hand measurement) to 3D laser scanning, which today represents the most advanced technology available for measuring and documenting objects, structures and landscapes.     

3D Digital Documentation,Assessment, and Damage Quantifi cation of the Al-Deir Monument in the Ancient City of Petra,Jordan

Abstract

The rock-cut monuments in the ancient city of Petra in Jordan form an outstanding tangible heritage site. Unfortunately, this important part of the world's cultural heritage is gradually being diminished due to weathering and erosion problems. In this research, an approach combining in situ surveying and laboratory analysis is applied in order to provide sufficient and comprehensive data regarding the documentation and evaluation of the status of the Al-Deir monument in Petra. The purpose was not only to quantify the damage, but also to make a first step towards creating a 3D monitoring programme of the deterioration rate. The approach presents a correlation study between the environmental condition and the surface weathering damage, using 2D mapping of the weathering form and accurate 3D realistic modelling from laser scanning and digital photogrammetry. The 2D mapping provides detailed weathering damage information for the entire stone surface of the monument, whereas the 3D modelling provides information on the spatial distribution and texture of the damage. Additionally, the 3D digital model can provide reference data as an exact guide to the restoration needed. In order to support the visual presentation of 3D surface details, a hybrid approach combining data from laser scanning and digital imagery was developed.

Studies of stone texture and spatial distribution of soluble salts were carried out at the monument in order to explain the mechanism of the weathering problem. Relative humidity, temperature, and wind are the main factors in the salt damage process. In order to study the effect of these conditions in the salt crystallization process a series of fieldwork investigations and laboratory work were undertaken. The results show that visible zoning of weathering damage is correlated to different salt concentrations.     

文物真三维数字建模技术在秦始皇兵马俑博物馆中的应用——以一号坑陶俑为例

随着高新技术的发展,文保应用研究中引入了三维扫描技术。通过对秦兵马俑一号坑陶俑的扫描实例,介绍了一套利用三维激光扫描技术建立文物真三维模型的基本流程及方法,并通过文物真三维数据管理系统对模型进行展示、分析与研究。文物真三维数据模型的建立,使全面观察研究、再现和重建遗迹及文物成为可能,为文物的数字化展示、数字博物馆的建立、文物鉴赏以及文化遗产的保存提供了新思路。     

Developing a documentation system for desert palaces in Jordan using 3D laser scanning and digital photogrammetry

Desert palaces in Jordan are unique pieces of art scattered in the desert as standing symbols of ancient civilizations. Due to their location, these palaces witness different environmental conditions which affect their status and sustainability. This raises the need to have a 3D documentation system reporting all spatial information for each palace, which can be used later for monitoring purposes. Digital photogrammetry is a generally accepted technique for the collection of 3D representations of the environment. For this reason, this image-based technique has been extensively used to produce high quality 3D models of heritage sites and historical buildings for documentation and presentation purposes. Additionally, terrestrial laser scanners are used, which directly measure 3D surface coordinates based on the run-time of reflected light pulses. These systems feature high data acquisition rates, good accuracy and high spatial data density. Despite the potential of each single approach, in our opinion, maximum benefit is to be expected by a combination of data from both digital cameras and terrestrial laser scanners. By these means the efficiency of data collection as well as the geometric accuracy and visual quality of the collected textured 3D models can be optimized. Within the paper, a 3D documentation system for Umayyad desert palaces in the Jordan desert will be presented using digital photogrammetry and laser scanning. The approach is demonstrated by generating high realistic 3D textured models for Amra and Kharanah palaces.     

Commercial Archaeology and 3D Web Technologies

ABSTRACT

This contribution summarizes the multiple uses of 3D web technologies in commercial archaeology. Considering the breadth of this topic, we will describe each different branch of these technologies with the example of case studies based on work of the Italian company Arc-Team. Our overview begins with 3D visualization for scientific purposes, showing a project funded by the Autonomous Province of South Tyrol (Italy) in order to improve knowledge about WWI. Second, we analyze a similar project, funded by the Autonomous Province of Trentino (Italy), but with the aim to increase tourism at a high alpine WWI site. The third example is the development of another prototype for tourism: a 3D web-map for the cultural valorization of the historical border (1753) between the region Tyrol and the Most Serene Republic of Venice. In the forth case study, we discuss the implementation of 3D within web platforms for archaeological project management of RAPTOR (Ricerca Archivi e Pratiche per la Tutela Operativa Regionale), a webGIS developed to aid in preservation and conservation efforts of cultural heritage for the Italian Ministry of Cultural Heritage and Activities and Tourism (MiBACT). Fifth, we explore recent uses of 3D models for web-coworking during the process of excavation management, thanks to the developments of real-time 3D acquisition techniques based on SLAM algorithms and archeorobotic devices. Finally, 3D web-coworking is also analyzed illustrating some simple web tools that afford rapid feedback in data visualization, considering not only excavation field-work but also exploration projects. This overview, based on six different case studies, represents the four fields in which 3D web technologies are currently used in commercial archaeology: scientific communication; tourism improvement; preservation of cultural heritage; and real time field-work management. Some specific topics such as tourism improvement and field-work management are investigated in greater depth in order to allow us to analyze variables deriving from customer requests (e.g. restrictions regarding sensitive geolocation or preferences for specific web platforms) and from differences among data acquisition technologies based on various sensors.     

New tools for rock art modelling: automated sensor integration in Pindal Cave

This paper presents the integration of automated sensors based on a terrestrial laser scanner and an amateur digital camera with the aim of generating a photorealistic three-dimensional (3D) model of the Principal Panel in Pindal Cave (Spain). The approach developed for 3D modelling overcomes many of the problems related to the independent implementation of photogrammetry and laser scanning. Particularly, a sequential and hierarchical approach was developed based on the processing and matching of images from the camera (camera image) and the laser scanner (range image). The results obtained demonstrate that the workflow for this model is automatic, effective, and accurate. The presented approach was found to create hyper-realistic models, even improving upon human visual capabilities.     

基于海量点云数据的大雁塔三维重建

古建筑三维重建已成为历史遗迹保护与修复的重要内容。为了探讨三维激光扫描数据的获取流程、数据处理方法,以三维激光扫描获取的大雁塔海量点云数据为例,研究了古建筑三维重建中点云数据获取与处理的详细过程。联合Cyclone、AutoCAD和3D-Max软件的优点构建了大雁塔真实的横面、剖面、立面模型,其中重点研究了海量点云数据在Cyclone软件中分块建模的方法。结果表明:将拼接好的大雁塔海量点云数据分块建模,不仅加快了数据处理的速度,而且符合精度要求。在点云数据拼接时采用标靶拼接和同名点拼接相结合及测站间两两拼接之后再整体拟合平差的方法,减少了拼接中的误差,使每站拼接误差都不超过3cm。在建模过程中的墙体拟合是上万个点云经过平差计算得到,精度高达2mm。最后在3D-Max软件中组合、渲染和贴图,真实地构建了大雁塔三维立体模型。为古建筑数字化存档和后期的修缮工作提供了重要的依据。     

3D geometrical modeling of excavation units at the archaeological site of Tell ‘Acharneh (Syria)

3D geometric modeling consists of representing geometric and spatial relationships of volumetric objects. We think it could be helpful in the context of archaeological excavation units representation and analysis. This article presents a procedure developed to generate 3D models from GPS positions taken at the top and the bottom of the excavation units boundaries on the archaeological site of Tell ‘Acharneh (Syria). It shows and discusses two geometrical modeling approaches (voxel and tetrahedral) used in the Gocad 3D modeling tool. Once excavation units are geometrically modeled, it is possible to refer them within a trench or the entire archaeological site, to handle them in various ways (zoom, rotation, translation), to perform on them 3D spatial analysis such as volumetric calculus or intersection computation, to make various kinds of queries such as to find out excavation units that have a certain number of artefacts, to generate sections anywhere in the 3D model, and finally to publish it with VRML (Virtual Reality Modular Language). As well as improving data analysis techniques, we think that if this 3D modeling operation can be done during the excavation, it could greatly help archaeologists to plan more efficiently their daily excavation strategy.     

缺失彩绘的虚拟三维重建——秦俑彩绘

利用三维测量技术和计算机技术,以及科学的数据计算,计算机可以制造出虚拟三维形象,便于展示与交流。至今为止,秦俑坑中出土的大多数陶俑的彩绘留存不多甚至没有。色。大部分原始彩绘均已脱落,只有极少部分彩绘保留至今。本文以虚拟三维模型重构了秦俑原始彩绘,显示了其功能与意义。俑（T21G18-03）是这次工作的对象。陶俑主要显现出灰暗的陶一尊将军俑（T9：1）和一尊跪射陶俑出土时彩绘的纪录档案是重构工作的出发点。通过三维扫描仪将陶俑表面形状进行数据记录,这是重构工作的基础。然后通过数码照片记录彩绘现状,并将这些照片进行三维机理处理。采用三维绘制软件进行重建和摹绘工作。数据模型过程可以模拟和大多数彩绘和表面情况。这项工作的开展通过几件典型陶俑,将秦俑的原始状态展示给大家。通过计算机模拟,多彩的秦俑军阵活灵活现的呈现在观众面前。     

现代测绘技术在古建烫样数字化项目中的应用

烫样是研究清代皇家建筑的珍贵文物,为配合文物信息数字化工作的开展,针对烫样数据的采集和处理方法进行了深入研究。在综合考虑多种数据采集方法的特点及烫样数字化记录的难点后,选择使用手持式三维扫描仪与多视角三维重建技术相结合的方式来进行烫样的基础数据采集,并通过实践总结出了一套完整的数据采集和处理工作流程。与此同时,针对成果可能的应用方式做了些许尝试,且为数据的后期维护与进一步利用拟定了数据管理系统的建设方案。     

Modeling and deterioration mapping of façades in historical urban context by close-range ultra-lightweight UAVs photogrammetry

Deterioration mapping of façades may be a challenging task in historical urban contexts, often characterized by narrow streets and tall buildings. In these situations, the application of Terrestrial Laser Scanning or Terrestrial Photogrammetry does not provide satisfactory results. Furthermore, the use of Unmanned Aerial Vehicles, the so-called “drones”, is generally forbidden in crowded places for safety reasons unless they are lighter than a weight imposed by the regulations in force in each country. This article presents the application of a very small and ultra-lightweight drone (less than 300 g) equipped with a low-cost camera, particularly suitable for operating in very narrow spaces. A close range photogrammetric survey performed to analyze a huge historical building façade in Bologna (Italy) pointed out a good accuracy level, confirmed by the validation of the results carried out by a 3D laser scanner survey. Moreover, a map of the degradation has been realized to support further restoration analysis, demonstrating that this low-cost, fast, and easy-to-use survey technique can be applied to other similar urban contexts at the same time.     

Ancient standards of volume: negevite Iron Age pottery (Israel) as a case study in 3D modeling

Hand-made cylindrical vessels unearthed in excavations of Iron Age IIA sites in the Negev Highlands constitute the largest and most dominant ceramic assemblage of simple-shaped vessels found in Israel. The volumes and linear dimensions of these vessels were analyzed based on computer 3D models reconstructed according to their drawn profiles. This analysis revealed the rules that could have been employed by the ancient potters in order to produce vessels of given volumes. These rules demonstrate the human ability to reveal approximate (but inherent) geometric relationships between form and volume and deploy them in everyday life.