Mapping by matching: a computer vision-based approach to fast and accurate georeferencing of archaeological aerial photographs

To date, aerial archaeologists generally apply simple rectification procedures or more expensive and time-consuming orthorectification algorithms to correct their aerial photographs in varying degrees for geometrical deformations induced by the topographical relief, the tilt of the camera axis and the distortion of the optics. Irrespective of the method applied, the georeferencing of the images is commonly determined with ground control points, whose measurement and identification is a time-consuming operation and often limits certain images from being accurately georeferenced. Moreover, specialised software, certain photogrammetric skills, and experience are required. Thanks to the recent advances in the fields of computer vision and photogrammetry as well as the improvements in processing power, it is currently possible to generate orthophotos of large, almost randomly collected aerial photographs in a straightforward and nearly automatic way. This paper presents a computer vision-based approach that is complemented by proven photogrammetric principles to generate orthophotos from a range of uncalibrated oblique and vertical aerial frame images. In a first phase, the method uses algorithms that automatically compute the viewpoint of each photograph as well as a sparse 3D geometric representation of the scene that is imaged. Afterwards, dense reconstruction algorithms are applied to yield a three-dimensional surface model. After georeferencing this model, it can be used to create any kind of orthophoto out of the initial aerial views. To prove the benefits of this approach in comparison to the most common ways of georeferencing aerial imagery, several archaeological case studies are presented. Not only will they showcase the easy workflow and accuracy of the results, but they will also prove that this approach moves beyond current restrictions due to its applicability to datasets that were previously thought to be unsuited for convenient georeferencing.     

A new method to remove copper corrosion stains from stone surfaces

This paper reports on a methodological study carried out in order to propose a cleaning procedure to remove stains produced by bronze corrosion products on surface of limestone (namely travertine); the procedure is effective and more environmentally friendly than the methods commonly used today. Several copper complexing or chelating agents were considered, including three amino acids and compared with some ion exchange resins. After a first laboratory phase on pure copper products and on artificially stained quarry samples, the optimized procedure was tested on the pedestal of a bronze statue in the Sapienza campus, in Rome. Colorimetry and ICP/OES were used to evaluate the efficiency of the cleaning procedure.     

A novel method for integrated age and sex determination from archaeological cattle mandibles

Analysis of ancient cattle husbandry is compromised by the need for conventional analysis of sex and age at death to use different elements of the skeleton, usually from different individuals. We demonstrate a technique using aDNA acquired from cattle mandibles and combined with age-at-death estimation based on dental eruption in the same specimens. Application to small sample groups from two sites in Na h-Eileanan Siar (the Scottish Western Isles) show a high success rate, and demonstrates the potential for a more nuanced interpretation of ancient cattle husbandry.     

A method for chronological apportioning of ceramic assemblages

Artifact assemblages from long-inhabited sites may include ceramic types and wares from multiple time periods, making temporal comparisons between sites difficult. This is especially problematic in macro-regional data sets compiled from multiple sources with varying degrees of chronological control. We present a method for chronological apportioning of ceramic assemblages that considers site occupation dates, ceramic production dates, and popularity distribution curves. The chronological apportioning can also be adjusted to take into account different population sizes during the site occupation span. Our method is illustrated with ceramic data from late prehispanic sites in the San Pedro Valley and Tonto Basin, Arizona, U.S.A., compiled as part of the Southwest Social Networks Project. The accuracy of the apportioning method is evaluated by comparing apportioned assemblages with those from nearby contemporaneous single component sites.     

A new method for identifying sherd refits: A case study from the Neolithic of Northumbria,U.K.

Abstract

Here we present a flexible, quantitative methodology for refitting handmade ceramics. Rather than analyzing the physical joins between sherds, we assess the likelihood that non-adjoining sherds of similar appearance are from the same vessel. The customary disregard of non-adjoining sherds in refitting experiments prompts us to address this issue. Using the Neolithic ceramic assemblage from Thirlings (Northumberland, U.K.) as a case study, we test several scoring systems for assessing the probability of two sherds pertaining to the same vessel. The utility of this approach is supported by the comparison of a set of percentage scores statistically verified using Spearman’s rank correlation coefficient. We conclude with a discussion of the contribution of the new method to post-excavation ceramic analyses, and its applicability to other assemblages.     

Detection of chloride from pottery as a marker for salt: A new analytical method validated using simulated salt-making pottery and applied to Japanese ceramics

Salt is an essential mineral in the human diet, and ancient peoples obtained salt either directly from rock salt, from salt lakes, or by concentrating saline waters from salt springs or seawater in pottery vessels. However, because sodium chloride, the major component of salt, is soluble in water, it has been thought unlikely that any trace of salt would remain in the pottery after a long period of time. A new methodology for retrieval of water-insoluble (retainable) chloride ion trapped within a pottery matrix is presented as a method for detecting previous use of the pottery for salt making. Simulated salt-making pottery was used to make salt by repeatedly boiling seawater over a fire. After chloride had been extracted with distilled water, to mimic the removal of chloride by natural waters such as rainwater and groundwater, an aqueous ammonium fluoride solution was shown to be capable of extracting chloride ions remaining in the pottery. A chloride-selective electrode was used to quantify the amount of extracted chloride in the presence of fluoride. This method was then successfully applied to excavated Japanese pottery vessels suspected of having been used for making salt. Identification of retainable chloride in pottery can offer insights into salt trading networks, which reflect the growth and affluence of an ancient society.     

A spatial method for integrating data of different types

Systematically recording archaeological, historical, ethnographic, and other information in a geographical-temporal frame has great advantages. The method allows the logical ordering of disparate facts, error checking, making connections that might otherwise go undetected, better comparison, manipulating temporal and spatial scales, and specifying the fields within which causal processes do and do not operate. The application of this spatial method in the Valley of Oaxaca, Mexico, generated new hypotheses about the late prehispanic-earlies colonial transition; it brings us closer to a single history, as opposed to segregated prehistory and history.     

A method for estimating edge length from flake dimensions: use and implications for technological change in the southern African MSA

This paper presents a method for estimating edge length from flake dimensions. Comparison of estimated values with data from measured flake edges demonstrates the robusticity of the method. Building on the work of Braun (Braun, D.R., 2005. Examining flake production strategies: examples from the Middle Paleolithic of Southwest Asia. Lithic Technology 30, 107–125; Braun, D.R., Harris, J.W.K., 2003. Technological developments in the Oldowan of Koobi Fora: innovative techniques of artifact analysis and new interpretations of Oldowan behavior, in Mora, R., de la Torre, I. (Eds.), Oldowan: Rather More than Smashing Stones. Treballs d’ Arqueologia 9, pp. 132–144) this estimate is used to generate an edge length to mass value for complete flakes—taken to be a proxy for flaking efficiency. It is shown that this value is useful in tracking the onset, variability and decline of a well known technological phase—the Howiesons Poort of South Africa. The results suggest that the Howiesons Poort was a time in which flaking efficiency was emphasised. Furthermore, comparison of upper limits of edge to mass values for different raw materials may provide an insight into changes in raw material selection.     

Ancient Iberian horses: a method to recover DNA from archaeological samples buried under sub-optimal conditions for preservation

Existing methods to extract, amplify, and sequence ancient DNA (aDNA) from horse bone and teeth were optimized to recover DNA from a depositional environment of highly permeable acidic soil. DNA was successfully retrieved using 0.10g of bone powder from horse (Equus sp.) remains dating to 25 K years utilizing the methods optimized for this archaeological material. The genetic analyses were performed in a facility that is dedicated to ancient DNA research (Paleo-DNA Laboratory, Thunder Bay, ON, Canada) and has not been previously used to analyse modern or ancient horse DNA. Research was replicated to obtain reliable sequencing results for six samples from the Iberian Peninsula that were consistent with published sequences of Equus caballus. The archaeological sequence data obtained support hypotheses that promote the significance that the Iberian Peninsula has had to the multi-focal centres of origin for horse domestication and distribution of modern horse breeds. The data presented may provide evidence of the existence of an Iberian refugium for Equus during the last glacial period, 10 K years BP. Further molecular data analyses will enhance the ideas presented by this data and our understanding of horse domestication and phylogeny. The optimization of molecular techniques to successfully obtain DNA using minimally destructive, cosmetically sensitive techniques from archaeological remains endeavours to foster further cooperation between museums and researchers.     

Dental wash: a problematic method for extracting microfossils from teeth

A variety of microfossils, originating from plant foods, become trapped in the dental calculus matrix. Processing of dental calculus allows extraction of these microfossils. The resulting data can be used to reconstruct diet at the individual and population levels as the identification of microfossils like starch grains and phytoliths to the generic level, and sometimes to the species level, is possible. However, in some archaeological sites, dental calculus deposits do not preserve well enough to be processed. To prevent the loss of information in such cases, we present a technique, called “dental wash”. It permits extracting microfossils from cryptic dental calculus deposits. In the two experimental archaeological cases presented herein we identified phytoliths, starch grains as well as a diatom fragment with this method, whereas in a control sample no microfossils were found. Moderate damage to the teeth was detected when they were already friable due to poor preservation. Minor damage to the surface of well-preserved teeth was observed. This indicates that the proposed method is efficient in recovering microfossils, but unacceptable because of damage to teeth. If the method can be refined, it will expand the potential of dental calculus analysis to a greater range of archeological sites.     

A statistical view for Chinese zooarchaeology: from the Neolithic to Pre-Han periods

More than 80 years have passed since zooarchaeology first began in China in the early 1930s. Currently, this discipline is one of the most active fields in Chinese archaeology, engaging with other sub-disciplines such as archaeogenetics, archaeobotany, and stable isotopic studies. But how did we end up like this? This paper explores this question by surveying existing zooarchaeological publications from the Neolithic to Pre-Han periods (c. 8000–202 bc). Results show that journals are the most popular publishing type, followed by archaeological reports. Postgraduate theses are also taken into account. With consideration of publication numbers, three chronological periods can be recognised. These phases are associated with political/social events of the twentieth century in China. While the majority of articles concern basic identification, there has been an increasing interest on human-animal interactions during recent years. In addition, while central China is the overwhelming focus of zooarchaeological research, some areas may have been overlooked.     

A new method for the quantitative analysis of cutmark micromorphology

Cutmarks found on the fossilised bones of butchered animals provide direct evidence for the procurement of meat through technological means. As such, they hold some of the oldest available information on cognitive ability and behaviour in human evolution. Here we present a new method that allows a three-dimensional reconstruction of cutmark morphology and the quantification of profile parameters. We have tested this new technique on cutmarks that were experimentally inflicted on a pig rib using a steel knife and an un-retouched flint flake at different angles. The method allows for the cross-sectional shape, the sharpness and depths of the resulting cutmarks to be quantified. The data show that knife mark sections are characterised by a V-shape or √-shape depending on the inclination of the knife. Cutmarks produced with the flint flake were less clearly defined and generally less sharp than those produced by the knife. We discuss the method's potential to provide new information on butchery technique and cognitive abilities developed by the human lineage, from the earliest tool-using hominins through to modern Homo sapiens.     

王国维致沈曾植的一通信札

嘉兴博物馆藏有王国维致沈曾植的一通信札,为沈曾植之子沈慈护（1898—1963年,名颎）于1959年捐赠。该信札共四页,＂小蓬莱阁＂红印宣笺,纵23.7、横16.1厘米。按顺序二页缀合,用硬白纸托裱成二册页,册页纵28.5、横18.5厘米。首页前钤＂沈颎之印＂、＂慈护长寿＂二白文方印,后页末钤＂静俭斋藏＂白文方印,证为沈慈护所收藏。信札全文按原件释录如下：乙乡先生大人尊鉴：里闬相望,不及百里;向往之切,又逾十年。而踪迹睽违,未得一奉几杖。其为企仰,何可胜言。每从蕴公处得读书疏并及诗翰,读＂道穷诗亦尽,愿在世无绝＂之句,始知圣贤、仙佛去人不远。