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1.
Accurate three-dimensional representations of cultural heritage sites are highly valuable for scientific study, conservation, and educational purposes. In addition to their use for archival purposes, 3D models enable efficient and precise measurement of relevant natural and architectural features. Many cultural heritage sites are large and complex, consisting of multiple structures spatially distributed over tens of thousands of square metres. The process of effectively digitising such geometrically complex locations requires measurements to be acquired from a variety of viewpoints. While several technologies exist for capturing the 3D structure of objects and environments, none are ideally suited to complex, large-scale sites, mainly due to their limited coverage or acquisition efficiency. We explore the use of a recently developed handheld mobile mapping system called Zebedee in cultural heritage applications. The Zebedee system is capable of efficiently mapping an environment in three dimensions by continually acquiring data as an operator holding the device traverses through the site. The system was deployed at the former Peel Island Lazaret, a culturally significant site in Queensland, Australia, consisting of dozens of buildings of various sizes spread across an area of approximately 400 × 250 m. With the Zebedee system, the site was scanned in half a day, and a detailed 3D point cloud model (with over 520 million points) was generated from the 3.6 hours of acquired data in 2.6 hours. We present results demonstrating that Zebedee was able to accurately capture both site context and building detail comparable in accuracy to manual measurement techniques, and at a greatly increased level of efficiency and scope. The scan allowed us to record derelict buildings that previously could not be measured because of the scale and complexity of the site. The resulting 3D model captures both interior and exterior features of buildings, including structure, materials, and the contents of rooms.  相似文献   

2.
Leaves of common deciduous trees: the horse chestnut (Aesculus hippocastanum) and linden (Tilia spp.) from the park, near one of the most important cultural institutions, the National Library of Serbia, were studied as bioaccumulators of heavy metal (Cr, Fe, Ni, Zn, Pb, Cu, V, As and Cd) air pollution. The leaf samples were collected from the urban park exposed to the exhaust of heavy traffic. The May–September heavy metal accumulation in the leaves, and their temporal trends, were assayed in a multi-year period (2002–2006). Comparing the obtained concentration of the investigated elements from the beginning to the end of growing seasons, a significant rate of accumulation was determined for a majority of measured elements, and it was concluded that these tree species (horse chestnut and linden) can be used as bioaccumulators of the investigated heavy metals. The SEM-EDAX analysis of individual particles deposited on the leaves showed that the 50–60% belong to a class of fine particles (D < 2 μm), mainly of anthropogenic origin. Thus, the investigated tree species could be grown as a natural barrier against urban air pollution in the vicinity of libraries, museums and other buildings for cultural heritage storage.  相似文献   

3.
3D reconstructions of small objects are more and more frequently employed in several disciplines such as medicine, archaeology, restoration of cultural heritage, forensics, etc. The capability of performing accurate analyses directly on a three-dimensional surface allows for a significant improvement in the accuracy of the measurements, which are otherwise performed on 2D images acquired through a microscope. In this work we present a new methodology for the 3D reconstruction of small sized objects based on a multi-view passive stereo technique applied on a sequence of macro images. The resolving power of macro lenses makes them ideal for photogrammetric applications, but the very small depth of field is their biggest limit. Our approach solves this issue by using an image fusion algorithm to extend the depth of field of the images used in the photogrammetric process. The paper aims to overcome the problems related to the use of macro lenses in photogrammetry, showing how it is possible to retrieve the camera calibration parameters of the sharp images by using an open source Structure from Motion software. Our approach has been tested on two case studies, on objects with a bounding box diagonal ranging from 13.5 mm to 41 mm. The accuracy analysis, performed on certified gauge blocks, demonstrates that the experimental setup returns a 3D model with an accuracy that can reach the 0.05% of the bounding box diagonal.  相似文献   

4.
Image-based modeling is an appropriate technique to create 3D models of cultural heritage objects, which starts with the basic task of designing the camera network. This task is, however, quite crucial in practical applications because it needs a thorough planning and a certain level of experience. The optimal camera network is designed when certain accuracy demands are fulfilled with a reasonable effort, namely keeping the number of camera shots at a minimum. In this study, we report on the development of an automated method for designing the optimal camera network for a given cultural heritage building or statue. Starting from a rough point cloud derived from a video image stream, the initial configuration of the camera network is designed, assuming a high-resolution HR state-of-the-art non-metric camera. To improve the image coverage and accuracy, we use a mathematical non-linear optimization with constraints. Furthermore, synthetic images are created to guide the camera operator to the designed images. From the first experimental test, we found that a target accuracy of 10 mm could be maintained although the initial number of more than 300 high-resolution images got reduced to less than 90 for the final, optimized network.  相似文献   

5.
Durability is one of the most important engineering properties of cultural heritage monuments. For the purpose of the preservation of structures for future generations, the causes of damage should be determined for the proper choice of type and location of strengthening. The condition of the foundation is difficult to determine without an extensive investigation which is critical because most often the cause of damage is found in such foundations. Geotechnical investigation techniques require the damage and destruction of a building's surroundings or the damage of a foundation with a boring device. Non-destructive methods, such as geophysical methods, are less reliable and the results of such investigations must be combined with the results of subsurface exploration. This paper is a presentation of results achieved through the monitoring of the activity of a number of joints on the Cathedral of St. Lawrence in Trogir, Croatia, which is a cultural heritage monument protected by UNESCO. Excavations for the purpose of flagging replacement in the zone around the east frontage were made in 1979. A probe beneath the main apse uncovered a water cistern where the connection between the mid and north apses is located, and instead of a staggered foundation, a wall with a depth of more than 2.2 m beneath the flagging was discovered. With respect to the given that churches were built on existing ones, it is possible to assume that this is a wall of the late-antiquity church described by Constantin Porfirogenet in the 10th century, built on and later adapted to the foundation for the new structure. The displacement in time of the construction elements of the cathedral were measured and recorded using non-destructive methods. Fissure displacement behaviour, air temperature and air humidity were monitored. The monitoring of the air humidity did not lead to any useful conclusion, so it was quickly dismissed. Observations of data were performed during two periods with an interruption between the two caused by insufficient monetary resources. Data from almost 8 years of continuous measuring are available. The aim of this paper is to present the data of the measured fissure displacements which were correlated with air temperature changes and mathematical models which were based on statistical analysis. Correlation coefficients show that the analysed fissures react to the air temperature changes with different intensities. The obtained data lead to the conclusion that the causes of the structural damage are not found within a displacement or failure of the foundations. Instead, the causes of the damage were found in other parts of the structure.  相似文献   

6.
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7.
Red lake pigments and dyes used in works of art were characterized by microspectrofluorimetry, a new tool in the field of cultural heritage. Emission and excitation spectra were obtained with high spatial resolution (8–30 μm) in cross-sections from paintings by Vincent van Gogh and Lucien Pissarro and from millenary Andean textiles. The fluorophores were identified by comparing their spectra with those from historic reconstructions assembled in a database. In the paints, purpurin and eosin lakes were detected. In the Paracas and Nasca textiles, dated from 200 B.C. to A.D.1476, purpurin and pseudopurpurin were the red dyes used. Carminic acid was detected in textiles dated close to the Inca Empire, A.D. 1000–1476. The results obtained with this new technique were confirmed and are in agreement with those obtained with conventional methods, requiring microsampling, such as HPLC-DAD-MS and SEM-EDX.  相似文献   

8.
The microgravity method is one of the geophysical tools used in engineering and environmental and archaeological researches, where the detection of subsurface cavities or buried structures is essential. In this study, this technique has been revealed to be an efficient and respectful tool for use in Cultural Heritage restoration studies, such as those carried out in the restoration of historical sites in which the elements to be examined are beneath a shallow coating of material. Therefore, the aim of this microgravimetric survey is to define the exact position and dimensions of a subsurface structure (rainwater cistern) through microgravity response of the medium.For this purpose, the subsurface structure of San Gerónimo Cloister of the Vall de Crist Carthursian Monastery (14th century) has been researched. This monastery was known to be the largest Carthusian Monastery in the region of Valencia (Spain) and one of the most remarkable of the ancient Corona de Aragón. A rectangular grid of microgravity measurement station points was designed to cover the entire surface of the cloister. In addition, a microgravimetric profile was acquired along a hillside close to the Carthusian buildings in order to obtain the density value of the medium.The study was performed using a LaCoste&Romberg D203 gravimeter to detect and to map the shallow subsurface rainwater cistern that probably exits beneath it. This gravimeter has a sensitivity of approximately 1 μgal (μgal = 1.10−8 ms−2) and an accuracy of 3–5 μgal for relative gravity measurements.Two contour maps were calculated (observed gravity and Bouguer gravity values) in order to improve the interpretation results. On these maps we can observe the shape of the body that is causing the perturbation in gravity values. And what is more, it led us to deduce that the central area of the cavity is deeper than the border area. In addition, we can asses that the cavity is 8 m wide and 12 m long, and is symmetrical along its longitudinal axis, but not along its transversal axis.Also, a microgravimetric inversion was performed and the subsurface is split into 7 prisms and the depth and height of each is to be estimated separately. As a result of this inversion we can estimate that the ceiling of the cistern is located about 1 m under the cloister pavement and the cistern floor at a depth of 4 m. The cistern is slightly inclined towards one of its edges by about 20 cm.Finally, the 2D modelling derived by microgravimetric data has allowed us to determinate the shape, dimensions and location of the cistern accurately. In addition we have calculated the cistern capacity (288 m3, that is, 2880 Hl). This capacity was quite enough for the water necessities of 13 monks who lived there permanently, even for making it through the drought periods frequent in this kind of Mediterranean areas.  相似文献   

9.
The brown carpet beetle Attagenus smirnovi, Zhantiev 1973 (Coleoptera: Dermestidae) is an important pest of objects of organic origin in museums of cultural and natural history in Europe. Future climate changes are expected to lead to increasing temperatures, which will affect the pest status of this species. In the present study a laboratory investigation was conducted to elucidate the effect of temperature and humidity on the amounts of organic material consumed by larvae of A. smirnovi. In the case of new and old skin, consumption was approximately twice as high at 28 °C compared to 20 °C. Wool was consumed in the greatest amounts: 169 mg of wool was consumed in three months by 30 A. smirnovi larvae. The expected future climate changes in Scandinavia are assumed to lead to higher temperatures in museums and stores where climate is not regulated. Updated data on the present distribution of A. smirnovi in Europe show that it is widespread and common, also in regions with a climate that does not support its survival out of doors. Thus, dispersal of this pest probably only rarely occurs by flight, but usually with human activity. Due to the widespread distribution of A. smirnovi, it is likely that damages in museums and collections in Scandinavia due to this pest will increase as climate changes come into effect.  相似文献   

10.
Short crystallisation and deliquescence cycles of mirabilite, epsomite and gypsum are identified by using an automated monitoring system on-site. It consists of digital cameras and RH/T sensors which are computer-controlled and connected to the Internet. Digital images are processed to form a time-lapse movie, so that surface alterations are easily recognised. High resolution imaging (6 mega pixels) in combination with various lenses (12–24 mm zoom, 28–105 mm zoom, 20 mm inversed) results in a wide range of precise observation from 7 to 500 mm width of image. That is essential for discriminating phase transitions of single crystals at the same time as monitoring the evolution of the efflorescence as a whole. Crystallisation-deliquescence cycles are induced by small temperature and humidity variations. Mirabilite and epsomite undergo phase changes from crystallisation to deliquescence and vice versa at about 83% RH (15–20 °C). These equilibrium relative humidities are considerably reduced compared to the pure salt systems as a consequence of mixed salt solutions. Observations confirm predictions by ECOS simulation based on chemical analyses of water extracts from the site. Dehydration of mirabilite is observed when the relative humidity drops below 65% RH. Mirabilite exhibits the most pronounced and rapid phase changes in response to indoor climate variations. As an example, whisker crystals of 1–3 mm length grow within one up to some days. Epsomite responds fainter and slower. Crystallisation of gypsum is distinguished by the growth of new crystals on the stone surface. They have a size of about 10 μ – which is close to the image resolution – when they appear on the image. Crystallisation is associated with an increased granular disaggregation of the stone surface. Rhythmical crystallisation of gypsum appears to correlate with small relative humidity variations of ±2–5% within a band from 65 to 75% RH in the room. However, this needs to be clarified in detail.  相似文献   

11.
Two multivariate statistical tools – principal components analysis and cluster analysis – were applied to aid in the interpretation of the historical development of St. John the Baptist's church (?i?e, Slovenia). With these methods it was possible to distinguish between the types of mortar used in the Romanesque and Gothic time periods. The investigated structure is a ruin with poorly preserved fragments of historical mortars, so tracing the individual stages of its construction proved to be a demanding task. Its chemical composition was determined by inductively coupled plasma mass spectrometry (ICP-MS) and the results of the content of various oxides were statistically evaluated to interpret the age of the southern wall of the church.  相似文献   

12.
Xuan paper is a type of Chinese handmade paper produced for traditional calligraphy and painting in China since the Tang Dynasty (618–907 AD), and is therefore an important cultural heritage material. In this study, the fluorescence and photochemical properties of Xuan paper were investigated. Xuan paper exhibits auto-fluorescence in the blue spectral range (450–500 nm) and UVA photolysis of the paper resulted in a substantial reduction in the blue fluorescence together with the formation of chromophores absorbing in the visible spectrum, resulting in photoyellowing of the paper. A more significant yellowing of paper was observed when irradiated in the dry state than under wet conditions. The associated photogeneration of hydrogen peroxide and superoxide from three types of Xuan paper samples during irradiation showed a correlation between the yields of reactive oxygen species and their relative yellowing rates. The results are interpreted in terms of sensitised photooxidation via a mechanism of electron transfer involving the fluorophores in their excited singlet states being responsible for the photodegradation of Xuan paper. SEM/EDS analyses were performed on the Xuan paper samples to investigate their morphological and elemental characteristics. Silica-containing fibres characteristic of a special rice straw that grows in siliceous soil were observed in all types of Xuan paper. Micron-sized calcium precipitates possibly formed from the “lime-steaming” manufacture process were shown to protect against the acidification of paper during accelerated thermal ageing.  相似文献   

13.
Solid-phase microextraction (SPME)–gas chromatography (GC)–mass spectrometry (MS) has been applied to the analysis of acetic acid and furfural that are emitted from the fibres of Phormium tenax (Xanthorrhoeaceae) [New Zealand flax] during degradation. Accelerated hydrothermal ageing of fibres of the Ruawai cultivar of P. tenax for 55 days at 70 °C resulted in the production of acetic acid at a level greater or equal to 1.65 mg g–1 fibre. This corresponds to only 8.5% of the acetyl groups present in the fibres. These groups are an important source of acetic acid, which is capable of damaging the fibres. The rate of production of acetic acid suggests that a heritage object made from the fibres of P. tenax, that was stored in damp ambient conditions, would undergo significant deterioration after a relatively short period. Other volatile products released during ageing included furfural, a series of short to medium chain aliphatic aldehydes that were derived from the oxidation of long chain unsaturated fatty acids on the fibres and a small group of products that were derived from carotenoids. The levels of furfural were determined to be approximately 0.75% of the potential production but at these levels, furfural could contribute to unpleasant odours from unventilated items. Fibres from six cultivars of P. tenax were found to release acetic acid and furfural all at the same rate. The levels of acetic acid that can be generated from these fibres are sufficiently high that low moisture levels and continuous change of air is required to minimize degradation of cultural objects that are made from these fibres and displayed in museum halls.  相似文献   

14.
Acetic and formic acid vapors emitted from woodwork in historical organs are very important corrosive agents for lead pipes. These acids are slowly released from the wood both during playing and when the pipes are silent. To inhibit this emission process, the wood surface can be modified, by creating a protective layer with alkaline features. However, a coating of wood is not recommended since this could modify the appearance and create a layer not perfectly compatible with the substrate. For this reason, we propose to use some innovative nanotechnology that has been successfully applied for the deacidification of wood samples coming from the Vasa shipwreck. Application of calcium (or magnesium) hydroxide nanoparticles, with sizes ranging from 30–150 nm, allowed a homogeneous distribution of particles through the surface layer of wood simply by soaking (or spraying) it in a alcoholic (or mixed with less polar solvents) dispersion of nanoparticles. Nanoparticles do not modify the wood appearance and distribute randomly within the first layers of wood. The small size of particles accounts for the high reactivity with CO2 from the air, to give the alkaline reserve of carbonates that provide high efficacy in the neutralization of gaseous acids. The emission of volatile organic compounds (VOC) from the treated wood was determined by using an emission test cell, Field and Laboratory Emission Cell (FLEC). The results show that the emissions of acetic acid vapor from nanoparticles treated wood was very low (< 70 μg/m2 h) during the first 13 month. In contrast, untreated wood emitted high concentrations of acetic acid vapor (200–400 μg/m2 h).  相似文献   

15.
‘Marmor Misium’ was one of the most used granites of antiquity, especially for the manufacture of columns and slabs. It was quarried in the area of Kozak (Turkey) and used locally from the Late Hellenistic period and later, probably at the end of the 1st century AD, exported to Rome and other important Roman towns of the Mediterranean sea. It seems that ‘Marmor Misium’ continued to be quarried until the Early Byzantine time; it is now still quarried for local use (road paving, etc.). In spite of its historical importance and geological interest, this granite has never been the subject of detailed petrological studies. That is why in this work it has been sampled from various outcrops of the plutonite and in abandoned ancient quarries and characterised petrographically and geochemically. From the petrographic point of view, the plutonites of Kozak are medium-grained biotite-hornblende granite and granodiorite composed of 34.2–53 % (modal) zoned plagioclase, 23.7–35.4 % K-feldspar, 21.4–29 % anhedral quartz, 4.9–10 % brown biotite and 7.7 % green hornblende. These rocks are I-type metaluminous granitoids of high-k calc-alkaline orogenic series forming a crystallised body at a depth of about 10 km. The positive distinction between ‘Marmor Misium’ and two other granites used in antiquity and macroscopically very similar to it, those from the Elba and Giglio islands (Italy), is easily made by considering the absence of hornblende, the peraluminous character and the lower Sr and Ba and higher Rb contents for the latter.  相似文献   

16.
Assessment of multi-leaf stone masonry in earthquake-prone areas is mostly related to the evaluation of its texture, morphology, leaf detachment and structural cracking due to previous seismic activity, as well as disintegration due to material deterioration. For the plastered masonry with heritage or artistic value (paintings, frescoes etc.), both the type of structure and the extent of damage should be characterized with minimal interference to the structure, which could be overcome solely by non-destructive testing (NDT). However, due to the complexity of plastered multi-leaf masonry structure, the performance of well-known NDT methods could be significantly worsened. Therefore, as a prerequisite for applying NDT on multi-leaf stone masonry in practice, a validation process should be carried out. In this study, complementary ground penetrating radar (GPR) and infrared (IR) thermography measurements on plastered laboratory three-leaf stone masonry walls were performed. Apart from assessing the wall texture and morphology with the type of connection between the leaves, detection of gradual plaster delamination and crack propagation while subjecting the walls to an in-plane cyclic shear test was taken into account. The results showed that GPR could successfully visualize header stones passing through the whole depth of the specimen. The masonry texture behind the plaster could be well resolved by both methods, although GPR near-field effects worsened its localisation. For the detection of plaster delamination, IR thermography outperformed GPR by detecting delamination as small as 2 mm as well as structural crack patterns, whereas GPR only detected delamination larger than 8 mm. It was shown that the performance of both methods for defect detection could be further improved by image fusion based on unsupervised clustering methods.  相似文献   

17.
We report the first results of a research study aimed at developing a new strategy for the conservation of wooden structural elements present in historical buildings, based on moisture regulating systems. As has been happening for artefact preservation in museums, the idea is to develop systems based on the ability of some highly hygroscopic materials to moderate variations in relative humidity. These materials could adsorb and release moisture to reduce the extreme values of humidity in the micro-climate, for example between wooden beams and masonry. In order to experimentally verify this possibility using current, low cost and easy handling building materials, 5 bentonite samples were laboratory processed to improve their adsorbing properties by means of treatment with sodium carbonate at 3 concentrations: 2, 3 and 4% by weight. The effectiveness of ion exchange between sodium carbonate and bentonite was controlled by measuring the swelling volume of the bentonites. All the samples (n = 15) were tested for their hygroscopic properties. Adsorption isotherms were measured at 25 °C, using desiccators with silica gel, saturated salt solutions and bi-distilled water. A comparison between isotherms of one of the lower hygroscopic treated sample of bentonite and of a sample of wood and of a sample of brick and some numerical analyses with the Delphin code were made in order to evaluate the potential use of this bentonite as a moisture regulating system for the preservation of historical wooden elements. Results show that it seems to be possible to use bentonites as a moisture buffering material in order to reduce moisture content in wooden beams at least during their adsorption phase. It remains to investigate their desorption phase and their behaviour if they be in a saturation condition. Further studies are currently under way.  相似文献   

18.
Black crusts formed on limestone built into the King's Gate represent the most important process in stone deterioration that is occurring in this part of the monumental complex of the Belgrade Fortress (Serbia). Of special importance is the association of salts (namely gypsum and syngenite). Syngenite is a common secondary deposit on granite monuments and on medieval stained glass (i.e., on K-containing materials). However, its appearance over calcareous substrates is not apparent, particularly in cases where cement mortar was not used for bounding. The origins of the potassium and sulphate ions required for syngenite formation are related to meteoritic water, which penetrates the soil above the arch of King's Gate. Water dissolves some soil components and becomes enriched with various ions before coming into contact with the limestone blocks. Enriched water contains two times more K+ and SO42? ions than pristine meteoritic water does. The source of the required ions is potassium-sulphate that is present in agricultural fertilisers that are used above the monument. The proposed mechanism for syngenite formation was additionally supported with laboratory experiment. The results of X-ray diffractometry and SEM-EDS analyses of limestone treated with potassium-sulphate solution and sulphuric acid suggest the possibility that the syngenite was formed over calcite:CaCO3 + K2SO4 + H2SO4 → K2Ca(SO4)2 H2O + CO2↑However, the complex mechanisms of gypsum and syngenite formation under natural conditions (variable concentration of potassium and sulphate ions, intermediates phases, temperature changes, humidity, the amount of disposable water etc.) do not exclude the possibility of syngenite formation over gypsum.  相似文献   

19.
This study is aimed at an assessment of the properties of two polymeric products applied to Norway spruce (Picea abies) and White poplar (Populus alba) wood species. It contributes to ongoing research experiments on the consolidating properties of two synthetic resins and their potential synergic action on wood, resulting from their different interaction with the substrate: Paraloid B72 and Regalrez 1126. Experiments were carried out on a series of samples of the two wood varieties. The consolidants were applied alone and one after the other, with one coat of Regalrez and then one of Paraloid. Porosity and variations in pore size distribution were ascertained by mercury intrusion porosimetry (MIP). Colorimetric and IR spectroscopic measurements were also taken before and after aging by solar radiation and freeze/thaw cycles, to verify the possible slowing of photodegradation of the treated wood and the consolidating resistance. Results confirm that both products penetrate the wood with a different behaviour. After double treatment with Regalrez + Paraloid, a significant advantage was observed in terms of mechanical resistance and pore size distribution, although no advantages as regards resistance to photo-oxidizing processes or colour changes were observed.  相似文献   

20.
This work shows the capability of principal component analysis (PCA) to detect molecular, chemical and mineralogical changes in historic painting materials subjected to a thermal ageing test (< 250 °C). To simulate the heat-induced alterations an ageing accelerated process was performed on two sets of samples containing two mineral phases (hydroxyapatite and quartz) and two organic compounds (collagen and albumin). The chosen minerals behaved as internal standards during the tests since they are stable and chemically inert at the tested temperatures. Raman microscopy (RM) was applied to characterise one set of samples made of bone, containing ca. 70% hydroxyapatite and 30% collagen. Attenuated total reflectance-Fourier transform infrared (ATR-FTIR) spectroscopy was used to study the other set of samples made of four different quartz/albumin mixtures with quartz contents of 30%, 50%, 70% and 90% (w/w). The aim was to identify the ideal proportion of internal standard to be validated by ATR-FTIR and PCA, determined to be 70%. PCA analyses detected changes in the molecular structures of the organic components while the internal mineral standard remained stable. Moreover, the internal standard IR/Raman bands were constant during the tests and confirmed that the results of PCA analyses were independent of instrumental and technical factors, as well as sample collecting and handling. This demonstrates the potential benefits of our approach to study historical painting materials, which have suffered any type of heat-induced alteration.  相似文献   

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