Decay regions segmentation from color images of ancient monuments using fast marching method

This work faces the problem of detecting decay zones from color images of stone materials. In Cultural Heritage, the extraction of degradation regions from images of ancient monuments represents an important step forward in studying and analyzing the state of preservation of historical buildings. Generally the decay diagnosis is provided by “naked eye” analysis done by expert scientists “walking around” the artifact and recording the conservation state of each individual element they observe. In addition to this kind of investigation, the application of an image segmentation strategy to color images of stony materials can be used in order to extract regions characterized by a visible chromatic alteration, changes in color, for example, as oxidation or concretion. This paper features a color image segmentation approach founded on the fast marching numerical method. We have applied this technique for its possibility to work locally, that is, only the contour of the region under study is processed. In addition to this method, we present a global approach, that is, the possibility to extract decay regions from the entire image; these regions are spatially disconnected but with similar colorimeter value. The main aim of the present work is to provide a tool that helps the expert to contour the degraded regions. In this sense even if the results of the proposed procedure depend on the expert evaluation, the approach can be a contribution to improve the efficiency of the boundary detection process. The study case concerns the impressive remains of the Roman Theatre in the city of Aosta (Italy). In the image segmentation process the color space L*a*b* is utilized.     

The Government's Choice of Bureaucratic Organisation: An Application to Italian State Museums

Italian state museums are characterised by a rigid bureaucratic structure and are almost completely financed by government transfers. In this paper we develop a simplified two-stage model in an attempt to explain how the government's preferences for differentiated museum functions may affect museum organisation. The model shows that the government prefers that complementary functions (e.g., conservation and scientific research) be produced by a single museum, whereas it prefers that substitutable functions (e.g., conservation and access by the general public) be produced by two museums. We use this prediction for an empirical analysis of the organisational structure of Italian state museums. On the basis of the unique ISTAT census of the Italian museum system, we test with two separate probit models the probability of observing in a state museum the concentration of either scientific activities of conservation and research or promotion activities for education and the general public. Higher classes of centralisation for the state museums are also considered by means of an ordered probit model. The results seem to suggest that the Italian state museum structure, as surveyed in the early 1990s, fully reflected the traditional policy model viewing museums as institutions devoted to conservation, scientific research and education. JEL-Classification: D73, Z11     

A color image segmentation method as used in the study of ancient monument decay

In the cultural heritage area, it is of fundamental importance to characterize and classify the conservation state of the materials constituting ancient monuments, in order to study and monitor their decay. Generally, the decay diagnosis is provided by “naked eye” analysis done by expert scientists “walking around” the artifact and recording the conservation state of each individual element they observe. In this paper, a color image segmentation approach, based on histogram threshold and edge detection techniques is presented, to extract degradation regions, characterized by holes or cavities, from color images of stone-materials. The goal is to provide an aid to the decay diagnosis by segmenting degraded regions from color images, computing quantitative data, such as the area and perimeter of the extracted zones, and processing qualitative information, such as various levels of depth detected into the same zones. Since color is a powerful tool in the distinction between objects, a segmentation technique based on color, instead of intensity only, has been used to provide a clearer discrimination between regions. The study case concerns the impressive remains of the Roman Theatre in the city of Aosta (Italy). In particular, we have processed and analyzed some color images of the theatre puddingstones, acquired by a camera.     

风土建筑挑战和身份认知方式:英国乡村保护的价值认知与保护制度初探

在乡村振兴的目标下,建成遗产该如何保护和存续在许多国家均是难题。通过追溯英国处置乡村中的风土建筑这一建成遗产的重要组构部分的整体特点,对其价值认知、保护历程及规划体系的形成,进一步结合科兹沃尔德乡村保护案例的规划政策分析,从三个方面分析了英国风土建筑保护的策源力。即包括贵族乡绅在内的精英阶层对乡村自然景观营造和保护旨趣一直有其社会传统性;赞美自然和乡村生活的浪漫主义者进一步通过包含风土建筑在内的英国风景建构为英格兰的民族身份认知物;英国作为工业革命的产生地,较早开始对工业文明的进程带来的后果进行反思,保护乡村的建成遗产及其整体环境作为善性立法和公共利益优先的原则的体现,并较早地通过制度建立被纳入正当化、合法性的保护框架中。最后指出英国社会普遍达成的有关风土建筑及其文化地景整体性保护的共识与规划制度的配合是英国乡村大范围的建成遗产能够被成功保护的关键所在。     

Water dispersed polymers for textile conservation: a molecular, thermal, structural, mechanical and optical characterisation

With the aim of identifying new water dispersed polymers for textile conservation, the structure and properties of three commercial polyacrylates and one commercial polyvinylacetate were analysed. The characteristics of these materials, not previously used in the conservation and restoration fields, were compared with that shown by Primal AC33 and Mowilith DMC2 and SDM5, widely used as consolidating or adhesive agents of ancient textiles. To achieve a thorough characterisation of each polymer, molecular, thermal, structural and mechanical investigation techniques were applied on film samples, obtained from polymer water dispersions through water casting at room temperature and/or compression moulding. The photo-oxidative resistance of these materials was also assessed by artificial weathering of water cast films and by measuring the Yellowing Index (YI) as a function of the exposure time under xenon-arc lamp. Collected data were used to appropriately compare the performances shown by these polymers when applied on artefacts consisting of natural fibres. In particular it was found that, among the products not previously used in the conservation and restoration fields, a high potential for carrying out treatments on textiles is shown by the samples commercialised with the trade names of Acrilem RP6005 and Acrilem 30WA. These products, in fact, exhibit properties that make them suitable as substitutes for Primal AC33 and Mowilith DMC2 and SDM5, respectively, depending upon conservation needs. It was very interesting to note that Acrilem 30WA, also after aging, shows YI values lower than that shown by Mowilith DMC2 and SDM5.     

Developing a toolkit for mapping and displaying stone alteration on a web-based documentation platform

Stone conservation at Chambord Castle and monitoring of its changes over time is actually an urgent necessity in order to preserve and enhance this historic and tourist site. Its porous stones suffer from degradation problems depending on physical and chemical parameters that are the origin of frequent restorations. The goal of this research is to supply authorities of the castle with a tool for scientific monitoring and decision support, based on the acquisition of alteration mapping and on the estimation of degradation patterns, in order to permit rational programming operations of restorations. This paper proposes an approach for digital documentation about the conservation state of buildings. The approach is based on the connection between a structured 3D model and structured 2D mapping data. In particular, in the NUBES web platform, a specific interface has been implemented, permitting the displaying and cross-reference of 2D mapping data on the 3D model in real time, by means of structured 2D layer-like annotations concerning stone degradation, dating, and material.     

An integrated and automated segmentation approach to deteriorated regions recognition on 3D reality-based models of cultural heritage artifacts

In the field of Cultural Heritage, image analysis represents an indispensable practice for restorers to collect information about the state of preservation of monuments and artifacts and plan restoration interventions. In addition, during the last two decades, the wide spread of remote sensing technologies and the possibility to build 3D reality-based models of artifacts allow the extension of image analysis to 3D environments. In this context, the purpose of this contribution is to show the results of investigations held in order to provide a methodology for the automatic detection of deteriorated areas within architectures and artifacts using colour images as a field of examination. Using both 2D and 3D segmentation approaches, our methodology aims at speeding and efficiently performing the automatic detection of deteriorated zones within Cultural Heritage and therefore segment 3D digital models acquired using different survey technologies. Within our investigations, we selected case studies concerning recurrent deteriorations, such as, for example, detachments, cracks and chromatic alterations; we run them both to manual and to automatic recognition and selection tests, in order to compare the results obtained using these approaches and evaluate the reliability of the automatic one. Results comparison included computational and user time, quantification of the deteriorated area error between manual and automatically detected zones. Additional parameters characterizing the specific type of deteriorations were also computed for each case study. Comparison between the automatic and the manual procedure showed that the automatic detection is faster and reliable in all our selected case studies, with evident improvements in the efficient evaluation of the entity and extension of deteriorated areas on 3D geometry.     

A multilevel approach for the damage assessment of Historic masonry towers

In the paper some case studies of damaged towers in Italy are presented: the Tower Masserano of Palace Ferrero - La Marmora at Biella, the bell tower of the Collegiata of San Vittore at Arcisate, and three medieval towers in Alba. A methodology is put forward for combining laboratory and nondestructive testing methods with monitoring systems in order to reach the goal of evaluating the state of conservation of historic towers and its evolution in time.     

An NDT electro-optic system for mosaics investigations

Electronic speckle pattern interferometry (ESPI) is a well-known tool in cultural heritage diagnostics. It is also suitable to reveal cracks and debondings of tiles in ancient mosaics of Roman and Medieval age. This paper describes a portable electro-optic system as a diagnostic tool to evaluate the state of conservation of ancient mosaics. The proposed system is based on the integration of ESPI and local speckle correlation techniques. Some experiments have been carried out on real, ancient, mosaics in laboratory and in situ. The different features of each technique are outlined and a comparison with holographic interferometry is also given.     

Assessing Quality in Cultural Goods: The Hedonic Value of Originality in Rembrandt's Prints

The definition of quality, and its consistent assessment, is a fundamental issue when dealing with collectibles. We analyze how originality is priced by the market. The market for prints by Rembrandt is considered. An original database has been built including almost 5,000 transactions in the international auction market during the period 1985–1998. The data allow us to control for many different characteristics (market, aesthetic, originality, authenticity, rarity, art history, techniques, conservation, etc.). The concept of “state” is used to measure originality. In printmaking a state is defined as the artist's creative phase, which occurs on the plate before inking and printing. We test whether (non-original) posthumous states are sold at prices lower than Rembrandt's own (original) states. The implicit price associated with the state has been found to significantly decrease if the state was later printed by someone else when it was no longer the master's intervention on the plate. Furthermore, a decreasing value among subsequent original states has proved to positively account for Rembrandt's direct invention. JEL classification: Z11, D46, C52     

Assessment of the state of conservation of stone artworks after laser cleaning: comparison with conventional cleaning results on a two-decade follow up

The utilization of laser light to produce fine and selective cleaning of superficial deposits and encrustation from stones was originally proposed more than 20 years ago by John Asmus who performed pioneering trials of laser cleaning on stone façades in Venice, Cremona and Padua. The opportunity to collect stone samples from these sites allowed us to carry out an original study aimed at evaluating the conservation state of stone surfaces cleaned 10–20 years ago by means of three different techniques: Nd:YAG laser radiation, micron sandblasting and chemical pads. Samples of various stone types, as Istria limestone, Botticino limestone and Nanto sandstone were collected and examined by means of optical and SEM microscopy, FT/IR, and EDAX analyses. The results provided preliminary indications that the state of conservation of stone surfaces previously subjected to laser cleaning is generally better in comparison with those which concurrently underwent mechanical and chemical cleaning.     

Painting technique and state of conservation of wall paintings at Qusayr Amra,Amman – Jordan

The state of conservation of the frescoes at Qusayr Amra was investigated by integrated physico-chemical measurements, particularly optical and scanning electron microscopy, μ-infrared spectroscopy, mass spectrometry and X-ray powder diffraction.The frescoes appear darkened and severely damaged owing to the deterioration of surface treatments and to the widespread presence of different salts. These caused significant detachments of the painting layers.The materials used in the painting and preparation layers and in the wall plaster were characterized in order to clarify the painting technique. Different pigments have been identified on the pictorial layers: the original ones correspond to green earth, yellow and red ochre, realgar, bone black and lapis lazuli and others, such as titanium white and cobalt blue, ascribed to recent restoration works. Proteinaceous materials (egg or yolk) have been identified as binders for the pigments, indicating a tempera painting technique.Three different products, belonging to restoration interventions, have been also identified: the natural product shellac, ascribable to next-to-last restoration and scarcely removed during last restoration also because of its insolubility, the synthetic vinyl acetate and acrylic polymers. Particularly the latter one indicates an on-going degradation of the applied fixatives.The extensive deterioration of the surfaces is also due to the widespread presence of salts, such as chloride, nitrate and sulphate clearly identified by XRD measurements.The obtained results give a comprehensive overview on the employed painting technique and its state of preservation and on the causes of the painting deterioration. Therefore, they are a fundamental tool to develop durable and compatible materials and methodologies for a future conservation strategy of this site.     

Neorenaissance/Neobaroque stained glass windows from Madrid: a characterisation study on some panels signed by the Maumejean Fréres company

This paper reports results derived from a chemico-physical characterisation study undertaken on an important ensamble of early 20th century stained glass windows from Madrid and signed by the prestigious and well-known Maumejean Fréres company. The study is part of an on-going project of restoration and conservation carried out by the National Glass Centre Foundation (FCNV, La Granja de San Ildefonso, Segovia, Spain). The basic aim of the research was to assess their current state of conservation and to study the degree of damage suffered throughout the last century by different materials employed in their production, namely colourless and coloured glasses, grisailles, lead cames, and putties used to fix glass pieces into the lead cames. Selected samples from these materials were characterised through optical microscopy (OM), X-ray fluorescence (XRF), scanning electron microscopy (SEM), energy dispersive X-ray microanalysis (EDX), VIS spectrophotometry, and X-ray diffraction (XRD). As a general rule, most of them presented an acceptable state of conservation, without any of the known degradation phenomena of more ancient stained glasses (e.g. Medieval, Renaissance, etc.). However, some remarkable alterations were observed. Important deposits of soot and dirt particles coming from a polluted urban environment were detected, producing a slow blackening of the panels. Resulting data have been useful to design and optimise a combined conservation and restoration strategy in the recovery of this valuable legacy of early 20th century stained glass windows from Madrid.     

Integrated reflectography and thermography for wooden paintings diagnostics

The need of inspecting a masterpiece of fine art without affecting it led to develop non destructive methods of investigation. In the field of art conservation, several diagnostic techniques are being widely used to inspect works of art, giving different but complementary results. The present work deals with two of these methods, reflectography and thermography, both techniques examining objects in the infrared spectrum but in different wavelength bands. Their integrated data potentially provide a powerful tool for mapping hidden features and alterations of artworks. This was confirmed during the inspections of a 13th century panel painting under restoration at the Opificio delle Pietre Dure laboratories (Florence, Italy). A graphical user interface was also designed to aid operators in the field of conservation dealing with the results of the two IR methods. Many options such as image adjustment, comparison, overlaying and transparency variation, in addition to thermographic elaborations, have been made available to users. Imaging data integration provides a multi-layered and multi-spectral representation of the painting that yields a comprehensive diagnosis confirms the anomalies individuation and reduces the ambiguities of information coming from a single diagnostic method.     

The scientific approach to the restoration and monitoring of mural paintings at S. Girolamo Chapel – SS. Annunziata Church in Florence

The scientific approach to the restoration and monitoring of mural paintings, at S. Girolamo Chapel – SS. Annunziata Church in Florence, is reported as a fruitful example of the synergic collaboration between restorers and scientists in the planning and development of conservative interventions. Before restoration, the painting technique and the state of preservation of the pictorial cycle have been investigated firstly by close examination of the painted surfaces and then by optical and/or SEM-EDS microscopy and μFT-IR spectroscopy on appropriately selected samples. In particular, the original constituent materials and those belonging to subsequent restorations were characterized together with those originating from decay processes. In this mural painting cycle, a peculiar “fresco” technique has been used although an auxiliary binder for pigment distemper has been also employed. The use of this technique, sometimes in an improper way together with uncorrected restoration interventions, are the main responsible of the unsatisfactory state of conservation of many painted areas. Preliminary conservation trials and scientific studies were carried out to design the most convenient restoration intervention and to verify the correctness and non-invasive of the necessary operations. Special attention was devoted to cleaning procedures, continuously monitored by a physico-chemical methodology, mainly based on microinvasive, microscopic and spectroscopic investigations, to evaluate the efficiency, advantages and drawbacks of the proposed cleaning procedures and define the most appropriate ones. Finally, specific decay markers have been recognized, by a comparison of the results obtained from the detached samples with those deriving from artificially aged models, to be used for a correct future monitoring and maintenance of the wall paintings.     

Preventive thermographic diagnosis of historical buildings for consolidation

Conserving architectural heritage usually requires a multidisciplinary approach involving a variety of professionals and organizations. Since the evaluation of the state of conservation of historical buildings using destructive techniques should be avoided to prevent the integrity of the cultural heritage, the development of non-destructive and non-contact techniques is very important. InfraRed (IR) thermography is a non-destructive powerful tool for fast and accurate building diagnostics. In the investigation of historical structures, where a restoration or conservation treatment can cause irreversible damage to the structure, it is considered to be of most importance. A campaign of thermographic surveys were conducted on a large part of the historical cultural heritage of L’Aquila and its surroundings. In this paper we present the results of the study for the Church of Santa Maria ad Cryptas (XIII century), one of the most ancient buildings in the surroundings of L’Aquila and one of the best examples of Gothic art in Abruzzo, with the aim to evaluate the correspondence between the damage induced by the earthquake and the previous thermographic results, in order to validate the effectiveness of thermography and its role in preventive diagnosis.     

Natural lighting in the Hall of Two Hundred. A proposal for exhibition of its ancient tapestries

The present paper provides a qualitative and quantitative approach to natural lighting design for the Hall of Two Hundred in Palazzo Vecchio (the present town hall) in Florence. Starting from transient simulation of natural lighting inside the Hall in its present state, using the commercial software Radiance, a design proposal was suggested, detecting the optimal conditions for tapestry conservation and maintenance and taking into account their periodical exhibition, designing a proper wall show-case solution. The suggested design does not modify the architecture and structure of the building. The distribution of natural lighting and consequently of the illuminance and luminance inside the ambient, suggested a solution for exhibition of the historical tapestries, which can guarantee not only tapestry conservation but also the Hall structure and its present uses. The design proposal provides a comfortable lighting environment, rehabilitation and improvement of the historical perception and sight of these works of art, under variable sun and sky conditions throughout the year.     

Diagnostic of the conservation state of antique Italian paintings on panel carried out at the Laboratorio di Restauro dell'Opificio delle Pietre Dure in Florence,Italy with ESPI-based portable instrumentation

The aim of this work was to use non-destructive optical measurement techniques to assess the conservation state of ancient Italian paintings and to experiment outside of the laboratory with the most recent ESPI (electronic speckle pattern interferometry) portable instruments developed within the Photonic Technologies and Diagnostic Laboratory of the European Commission Joint Research Centre of Ispra, Italy. The measurements described here took place at the Laboratori di Restauro dei Dipinti dell'Opificio delle Pietre Dure in Florence, Italy. The technique detects hardly visible and invisible defects on paintings on panel during the restoration phase and allowed the production of both qualitative and quantitative data, owing to its high resolution and sensitivity to thermal deformation. The system used allowed the inspection of a larger area (400×300 mm) in comparison to that reported in literature concerning continuous wave portable ESPI systems applied in the conservation field.     

Combining the travel cost and contingent behavior methods to value cultural heritage sites: Evidence from Armenia

This paper combines the travel cost method (TCM) with contingent behavior questions to estimate domestic visitors’ use values for cultural heritage sites in Armenia, a transition economy in which conservation of cultural monuments is hampered by limited resources. Respondents intercepted at four cultural monuments provided information on their visitation patterns, experience at the site, perception of the state of conservation of the monuments, and rating of the quality of the services and infrastructure. We combine actual trips with stated trips under hypothetical programs that would enhance the conservation of the monuments and improve one of (i) the cultural experience at the site, (ii) the quality of the infrastructure, or (iii) the quality of the services, and use the combined actual and stated trips to fit a panel data model. Our study is one of the few applications of the TCM to value cultural heritage sites. Our investigation shows that (i) significant use values are associated with the four study monuments, and (ii) conservation programs and initiatives that improve the cultural experience, or simply make it easier for the respondent to reach and spend time at the monument, are valued by domestic visitors and would encourage higher visitation rates. Actual and intended trips reported by the respondents exhibit good construct validity, in the sense that they are well predicted by price, location, hypothetical scenario and other individual characteristics of the respondents.

Heat and moisture promoted deterioration of raw silk estimated by amino acid analysis

Silks are amongst the most precious artifacts of our textile heritage. While most silk fabrics are made from degummed silk, some in collections, such as ancient Chinese Juan, are composed of raw or just partially degummed silk. Such silks with remnant sericin gum may require special consideration for their optimum preservation. Conservators and curators then need to know which of the silks in their collections are in this category, and what effect the sericin has on the ageing of silk fibres. In the study reported here, the artificial heat and moisture ageing of raw silk was investigated by means of amino acid analysis. Amongst various amino acid molar ratios, Asp/Gly proved a valuable indicator of residual sericin gum on aged silk. Measurement of the tyrosine content was also useful for gauging the conservation state of silk in some circumstances. The results of the amino acid analyses when combined with those for tensile tests suggested that sericin did not inhibit fibroin deterioration under the ageing conditions employed.