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。     

Laboratory Excavation of a Neolithic Grave from Avignon-La Balance-Ilot P (France): Burial Practices and Garment Reconstruction

The grave of La Balance-Ilot P, in Avignon, southern France, is an individual and isolated burial, attributed in the 1970′s to the Mesolithic or the Early Neolithic. The grave, partially unearthed, was exhibited and stored at the Calvet Museum until its rediscovery and laboratory excavation in 2009. We used 3D laser recording and field anthropological methods, followed by a multidisciplinary approach. The deceased, an adult male, was buried in primary deposition without any architectural features preserved. For the first time in the Mediterranean early Neolithic, this study led to the identification of a garment adorned with sophisticated embroidery using 158 red-colored Columbella rustica shells and 16 red deer canines. Calibrated AMS dates allow us to reliably place it in the early 5th millennium b.c. reinforcing evidence for long distance intercultural relationships in Europe during the Neolithic.     

运用科学技术方法对清代珐琅的研究

作者运用原子发射光谱、扫描电子显微镜、偏光显微镜和金相显微镜,对故宫博物院藏清代珐琅残片进行了实验分析。研究中.对构成珐琅的硅酸盐材料、铜材料、焊接材料以及镀金层的元素组成进行了测试;对珐琅残片断面的焊接层和镀金层的微观形貌、焊接层的金相组织进行了观察和鉴别。在此基础上,运用结晶学、矿物学、金属学和金相学的基础理论对珐琅原料种类、各种原料的作用、珐琅料的熔制与烧蓝、铜材料与焊接材料的合金属性、焊层的金相组织、掐丝珐琅的烧制工艺等问题加以探讨,试图藉现代科技手段揭示清代珐琅所包含的科学技术内涵。     

INTIMATE (Integration of Ice-core,Marine and Terrestrial Records) 20 Years on: Retrospect and Prospect

The INTIMATE (Integration of ice-core, marine and terrestrial records) project, the successor to the North Atlantic Seaboard Programme of International Geological Correlation Programme (IGCP-253) ‘Termination of the Pleistocene’, began in 1995 with the aim of integrating proxy climate records from around the North Atlantic during the Last Termination (18–8?ka BP). The INTIMATE remit has since expanded geographically to include the entire Atlantic basin and Australasia, while an extended temporal framework now covers the early Holocene and the Last Glacial cycle. This short paper outlines the principal achievements of the INTIMATE research community, which include the development of an event stratigraphy for the North Atlantic region; the establishment of protocols for ice–land–ocean correlation; important contributions to geochronology, most notably to tephrochronology, and to palaeoenvironmental and palaeoclimatic reconstructions; and the designation of the Greenland ice-core record as the global stratotype for the Pleistocene–Holocene boundary. Future directions of the INTIMATE programme are also briefly considered.     

A new approach to recording and monitoring wet-preserved archaeological wood using three-dimensional laser scanning

The analysis and preservation of organic materials preserved within wetland environments represents one of the most costly parts of any post-excavation strategy. This paper outlines the application of high-resolution terrestrial laser scanning to one class of preserved material, worked archaeological wood. Scanning allowed the recording of the artefacts in three dimensions and the identification of features such as toolmarks. Features can be measured and volumetrically modelled within the digital environment, which may not always be possible for these often fragile materials using conventional techniques. Repeat scanning of the artefacts provided an opportunity to use comparative analysis software to investigate changes in the morphology of artefacts under contrasting conditions of short-term storage. The results suggest that immersion in water results in the least deterioration, whereas both freezing and air-drying caused distortion and degradation. This paper demonstrates that laser scanning provides a viable alternative post-excavation method for the recording, analysis and long-term ‘virtual archiving’ of organic archaeological materials, which may be more cost-effective in some instances than other methods of preservation.     

Flake scar patterns of Clovis points analyzed with a new digital morphometrics approach: evidence for direct transmission of technological knowledge across early North America

Clovis points are the principal diagnostic artifacts of a Clovis complex that spread across North America between ca. 11,050–10,800 radiocarbon years before present. Clovis may be the best documented Paleoamerican culture in North America, but much remains to be learned about the movement and interactions of Clovis peoples. Similarities among Clovis points from geographically diverse locations have led some researchers to suggest that a uniform projectile point technology existed across North America during Clovis times. Others have rejected this idea, proposing local and independent technological adaptations to different regional environments. To investigate these ideas, we used digital morphometrics to analyze 50 Clovis points from nine different contexts. First, 3D surface models of the points were created with a portable laser scanner. Next, these models were digitally cross-sectioned through both faces, yielding two-dimensional isoheight contours of flake scar patterns that reflect the original reduction techniques used to shape the projectile points. In the final step, the contours were transformed with elliptic Fourier analysis into Fourier coefficient series, and patterns of variation and symmetry were explored with principal components analysis. When compared to modern Clovis point replicas made by an expert knapper, the flake scar contours of the ancient Clovis points showed little morphological variation and a large degree of bifacial symmetry. Our results support the existence of a widespread standardized “Clovis” knapping technique, most likely transmitted through direct interaction between knappers from different groups.     

三维激光扫描技术在土遗址保护中的应用——以隋唐洛阳城定鼎门遗址唐代道路遗址保护为例

在隋唐洛阳城定鼎门遗址唐代道路遗址保护中,运用三维激光扫描技术完整地收集了遗址表面的形貌信息,并建立了相关数据库。以此为例,说明三维激光扫描技术在土遗址保护中的作用和意义。     

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。     

3D imaging of Skoteino Cave,Crete, Greece: Successes and difficulties

Abstract

Interpreting cave use, especially from antiquity, requires the perception of subterranean space in all dimensions (floor to ceiling to lateral extent) including spatial variability resulting from geological factors. Subterranean conditions, coupled with variable atmospheric conditions, create a special environment not readily conveyed by conventional mapping techniques limited to two-dimensional floor plans. Skoteino Cave in north central Crete, Greece was used as a ritual and refuge site in the Bronze Age and later. Mapping of the cave attempted to depict and interpret prehistoric and historical use of this space by employing two mapping techniques: EDM total station mapping and terrestrial/point cloud laser scanning. Comparisons with earlier methods used to map cave show the advantages and disadvantages of various mapping schemes. To date, this was the first use of three-dimensional (3D) scanning to explore the complex shapes and space of a subterranean archaeological site on Crete (and the second such use in Greece), and this use demonstrates its own consequent successes and difficulties.     

Measuring core reduction using 3D flake scar density: a test case of changing core reduction at Klasies River Mouth,South Africa

A new core reduction index is presented, calculated as the ratio of flake scar number to 3D surface area (SDI). The index is tested experimentally on five types of core (blade, discoid, Levallois, biface and multiplatform cores) and then applied to the core assemblages from five sub-stages of the Middle Stone Age at Klasies River Mouth, South Africa. Preliminary results indicate that the SDI possesses the desirable attributes of a successful reduction index and is a significant improvement on traditional proxy measures of core reduction. The results of the archaeological case study confirm previous untested observations that cores from the Howiesons Poort and MSAIII sub-stages are more heavily reduced than preceding and following stages, and that local and exotic raw materials as well as different types of cores are all more heavily reduced during these periods. The SDI fills a significant lacuna in available core reduction measures.