Documenting Archaeological Mortuary Features using High Dynamic Range (HDR) Imaging

This technical note presents a refined technique for photo‐documenting archaeological mortuary features using High Dynamic Range (HDR) imaging. Mortuary features in archaeological context can be complex and delicate given the wide variability in grave constructions and preservation of human skeletal remains. It is therefore critical to obtain the greatest detail possible when photo‐documenting these features. HDR techniques represent more contrast in photographs and provide greater detail across the DR of illumination within mortuary features—where complex arrangements of human remains can obscure or darken other elements or associated funerary objects, making them difficult to identify in traditional photographs. HDR can be employed with most standard digital single lens reflex cameras used for archaeological field projects, is easy to learn and employ (as described here), can be processed and produced with commonly used photo editing programs, and is ideal for use in unpredictable conditions that are often encountered with archaeological mortuary features and in field conditions. Copyright © 2013 John Wiley & Sons, Ltd.     

高光谱成像技术在中国古代书画分析中的应用研究综述

中国古代书画，因其年代久远，递藏情况复杂，多数屡经裁切割补、修复重装，故而有很多历史信息或被叠摞或被遮蔽，导致今人不能以肉眼直接观察而获得，而纸绢接补，墨迹、颜料、印鉴的残损也为书画研究者带来诸多悬而未决的问题。近年来，高光谱技术作为一种非侵入式的光谱成像技术，已逐步应用于各类彩绘文物中，该技术可为中国古代书画研究和保护提供更丰富的信息。本工作以文献调研为基础，简要介绍了高光谱成像的原理及技术特点，对高光谱技术在中国古代书画研究的实践进行总结，梳理了国内外研究者利用高光谱技术在书画、档案及相关彩绘文物的增强显示、物质识别、虚拟修复方面的应用案例，以期为相关研究者提供参考借鉴。     

基于电阻率成像法的莫高108窟墙体内水盐运移过程分析

非均质的砂砾石层是莫高窟壁画的主要墙体,但砂砾石层的非均质性如何在水盐运移过程中发挥作用却还不清楚。为此,通过在108窟西壁面上1 m×1 m和2 m×2 m范围的三维高密度电阻率成像监测,发现在这些区域上,墙体电阻率的空间分布都是非均匀的,低阻值区域在空间位置、大小和形状上都会随时间而变化。这明确说明在构成墙体的非均质砂砾石层内存在着重要的水分饱和与非饱和过程(再分配过程),正是这一不断重复的饱和与非饱和过程促进了墙体内水分的运移和盐分在一些特定区域的聚集。研究成果对全面认识莫高窟墙体内的水盐运移机理,减轻和防治壁画盐害都具有重要意义。     

Mapping of the Buried Yarmouth Roads Wreck, Isle of Wight, UK, using a Chirp Sub-Bottom Profiler

Remains of the 16th-century Yarmouth Roads wreck, buried in sediments, were imaged using high-resolution geophysical techniques. The remains appear as strong reflectors underlain by an acoustic blanking zone, which was used to create maps of the wreck material. Close survey line-spacing allowed the construction of contour maps and hull sections, which revealed that the bow and stern sections are tilted to port at different angles, implying that they are detached. The seismic data have enhanced our understanding of the site beyond what was known from conventional archaeological investigations and confirms that this wreck was once a large carrack.
© 2007 The Authors     

Electric and magnetic tomographic approach for the geophysical investigation of an unexplored area in the archaeological site of Pompeii (Southern Italy)

The joint application of electric and magnetic techniques for near-surface exploration represents a very useful tool for archaeological investigation and can provide a quantitative contribution to describe the spatial distribution of buried objects. In this work we show a new advanced tomographic approach, based on the parallel inversion of magnetic and electric observed data, aimed at the reconstruction of the subsoil of a still unexplored area of the archaeological site of Pompeii (Southern Italy). The survey was performed in collaboration with Pompeii's Archaeological Commission. The comparison between the results obtained from the tomographic inversions of both electrical and magnetic data was carried out in terms of the data inversions, which allowed us to obtain information about the location of the buried geophysical sources in the investigated subsoil. The results obtained seem to be in a good agreement, both for the position of the geophysical sources and for their dimensions.     

The digital restoration of painted patterns on the No. 2 Qin bronze chariot based on hyperspectral imaging

The No. 2 Qin bronze chariot unearthed from Qinshihuang's Mausoleum is world famous for its huge size and colourful painted patterns. However, since it had been buried for a long time and was affected by its harsh environment, its painted patterns have been severely damaged. The traditional restoration methods, which mainly rely on expert experience, are manual, inefficient and lack scientific support. Moreover, to protect the important cultural relics, any invasive operations, such as sampling analysis, are strictly prohibited. This paper presents a method that combines hyperspectral imaging and computer technology for the digital virtual restoration of the bronze chariot's patterns. It is non-destructive, more efficient and more scientific. The method reproduces the damaged patterns with the following approaches: restoring the missing edges of the patterns; and distinguishing the different pigments. The obtained result implies that the method can digitally reproduce some of the damaged patterns, and that it can be used as a reference for recreating the patterns of the other painted bronze.     

CT imaging of human mummies: a critical review of the literature (1979–2005)

The number of computerised tomography (CT) investigations of mummies has increased since the first published study in 1979. However, this approach has never been validated. We present a critical analysis of the literature (1979 to 2005). Relevant articles were selected via a MedLine search and analysed according to CT technique, methodology, and author's speciality. Thirty‐one original articles matched our selection criteria. Of these studies, 42% were authored by radiologists, while 26% had no contribution from radiologists. Hypothesis‐driven papers comprised only 9.7% of the total. While 84% of the studies had a stated purpose for conducting the CT study, only 67% of studies defined their CT protocol clearly. CT was used to study mummification techniques in 74% of instances, and/or to detect disease in 58%. Conclusions based on CT analysis were derived in 84% of studies, but only 32% of these answered specific questions. Furthermore, only 36% of these conclusions were related to the stated purpose of the study. Using the criteria of the grading system we developed, we found that 61% of studies were supported only by weak evidence. We conclude that evidence‐based research with better design should be encouraged in future palaeoradiological studies. Copyright © 2008 John Wiley & Sons, Ltd.     

Optical Coherence Tomography for the non-invasive investigation of the microstructure of ancient Egyptian faience

Optical Coherence Tomography (OCT) is a non-invasive subsurface 3D imaging technique based on the Michelson interferometer. The non-invasive nature of OCT and its speed of acquisition makes it possible to image large volumes of intact objects to yield a complete overview of the microstructure. The production methods for ancient Egyptian faience were first investigated using scanning electron microscopy (SEM) imaging of the microstructure in polished sections and microprobe analysis of the composition of the glass phases. These studies were based on original Egyptian faience objects and laboratory reproductions of faience beads made using three different production methods. The microstructure of the same laboratory samples and the Egyptian faience objects from the British Museum Research Laboratory Collection are re-examined using OCT. It is found that OCT virtual cross-section images can be used to group ancient faience objects into three categories on the basis of the morphology of the surface glaze layer and the glaze/core interaction layer. The OCT images correspond well with SEM images of polished sections of ancient faience objects and laboratory reproductions. The virtual cross-sections produced by OCT are somewhat limited by the penetration depth, which is affected by the high absorption coefficient of the material and, therefore, cannot always provide information on the presence or absence of interparticle glass that binds together the quartz particles in the core. Nevertheless, the top two layers are well imaged and since OCT images can be obtained rapidly and without the necessity of removing a sample, the method can be applied to a very much wider range of ancient faience objects than is possible by SEM examination of polished cross-sections. In summary, this paper examines to what extent OCT can assist the investigation of the production techniques of ancient Egyptian faience.     

Use of Computed Tomography and Three‐Dimensional Virtual Reconstruction for the Examination of a 16th Century Mummified Dog from a North German Peat Bog

The corpse of a well‐preserved dog was recovered from a peat bog in the region of Burlage, Germany, in 1953. The dog, which dates to the 16th century, retained extensive soft tissue and fur on the postcranial body, although the head is skeletonised. Computed tomography was used to determine the extent of the preservation of the soft tissue, to determine sex and age and to attempt to identify trauma, pathology and potential cause of death. The analysis of the CT data indicated that the dog was an immature or adolescent male. Substantial soft tissue was preserved, including some internal organs. The entire skeleton was present, with the exception of the mandible and parts of the paws; all of the bones were flattened and some were distorted because of demineralisation in the peat. Partial disarticulation of the vertebral column was postmortem, although there was no further evidence of trauma or pathology on the skeleton or soft tissue. The cause of death could not be conclusively determined. To the knowledge of the authors, this dog represents the only known example of a complete historical nonhuman bog body with preserved soft tissue. Copyright © 2011 John Wiley & Sons, Ltd.