GrainAutLine: an Environment for Semi-Automatic Processing of Marble Thin Section Images

GrainAutLine is an interdisciplinary microscopy image analysis tool with domain specific smart functions to partially automate the processing of marble thin section images. It allows the user to create a clean grain boundary image which is a starting point of several archaeometric and geologic analyses. The semi-automatic tools minimize the need for carefully drawing the grain boundaries manually, even in cases where twin crystals prohibit the use of classic edge detection based boundary detection. Due to the semi-automatic approach, the user has full control over the process and can modify the automatic results before finalizing a specific step. This approach guarantees high quality results both in cases where the process is easy to automate, and also if it needs more help from the user. This paper presents the basic operation of the system and details about the provided tools as a case study for an interdisciplinary, semi-automatic image processing application

5000 Jahre Marmorgeschichte in Troia und in der Troas. Petroarchäologische Untersuchungen zur Herkunftsanalyse von weißen Marmoren in West Anatolien

This study presents the first archaeometric results on Trojan white marble artifacts, using a multitude of analytic techniques. These artifacts were provided by the Troia Project, led by the late Professor Korfmann, and date from the Prehistoric to the Roman Empire. The primary goal of the study was to determine the provenance of the raw materials from which these marble objects were made. Previous archaeometric results on Turkish and Greek marbles showed that provenance questions are often difficult to answer, even if a number of methods are available to study the material. A review of the existing data revealed that the archaeometric data are incomplete and, in turn, some sources seemed to be missing or were not yet analysed in detail. In order to increase our knowledge of the local material, the characterisation of a great number of marbles from West Anatolia was carried out for provenance purposes. During the provenance analysis, a number of methods were applied to the Trojan archaeological samples and on marbles of the nearby regions, especially in the Troad and neighborhood. Many traditional techniques were used, such as macroscopic and microscopic investigation, grain size analyses, chemical investigations (RFA, AAS), the use of stable isotopic ratios (δ18O und δ13C), and, furthermore cathodoluminescence studies. In order to determine the mineralogical composition XRD and EMPA were used. Additionally, 87Sr/86Sr ratios were measured. The quantitative textural analyses (QTA) that were used from time to time since the 1990s; were applied to the Trojan and West Anatolian marbles, moreover this method was improved and refined for the purposes of determining the provenance of the marbles. Despite the fact that marble is a common material in the Troad and neighboring area, scarcely any of the investigated raw material stems from these quarries, neither in the Prehistoric nor Hellenistic nor Roman periods. The raw material of the investigated archaeological objects of the Prehistoric times stems from quarries in Southwest Anatolia; a few of them can be categorized as imported goods from Paros and Naxos. The raw material of the building stones of the Hellenistic and Roman periods was transported predominantly from Marmara, while a few of them also stem from Paros and Thasos. However, one new marble type can be recognized: it originated from Karabiga, close to Troia on the mainland of the Biga Peninsula on the opposite side of Marmara Island. As a “by-product” of the study, a decision tree was developed, primarily for the Trojan and related marble material that defines a logically ordered sequence of measurement techniques, depending on the results of preceding measurements. Thus, this decision tree can be used to minimize the amount of the sample that has to be removed for analyses and also reduce the costs involved while maximizing the chances of determination the place of origin. Since marble raw materials are available for study in different forms, like powder or fragments and in some cases thin sections cannot be created for quantitative textural or cathodoluminescence analyses, sample-type-specific decision trees were constructed, based on applicable methods. These decision trees may turn to be useful in provenance studies of other white marble occurrences as well.In dieser Studie werden die ersten Ergebnisse der archäometrischen Untersuchungen von Artefakten und Baumaterialien aus weißem Marmor aus Troia/Türkei vorgestellt. Die untersuchten Objekte stammen aus einer Zeitspanne vom Chalkolithikum bis zur Römischen Kaiserzeit und wurden vom Troia Projekt (damals unter der Leitung vom Prof. Korfmann) zur Verfügung gestellt. Das primäre Ziel der Studie war es, die Herkunft der Rohmaterialien dieser Marmor-Funde zu bestimmen. Vorherige archäometrische Untersuchungen an anatolischen und griechischen Marmoren zeigten, dass die Frage nach der Herkunft oft schwierig zu beantworten ist, obwohl zahlreiche Methoden zur Verfügung stehen. Eine erste Zusammenstellung der vorhandenen Daten ergab, dass die Informationen und Daten über das Rohmaterial Marmor unvollständig sind. Einerseits wurden noch nicht alle Marmorvorkommen untersucht, außerdem sind die angewandten Methoden von Lokalität zu Lokalität sehr unterschiedlich. Aufgrund dieser Problematik und um unser Wissen über die lokalen Materialien zu ergänzen, wurde im Rahmen dieser Arbeit die Charakterisierung einer großen Anzahl von Marmor-Lagerstätten aus West Anatolien, zu Zwecken der Provenienzforschung durchgeführt. Um die Herkunft der Rohmaterialien der untersuchten Objekte aus Troia zu bestimmen, wurden eine Reihe von traditionellen Untersuchungsmethoden angewandt sowohl an den archäologischen Materialien (62 Proben) als auch an den Rohstoffen (239 Proben), wobei schwerpunktmäßig die Marmorvorkommen in der Troas und Umgebung aufgesucht, beprobt und untersucht worden sind. Die Untersuchungsmethoden reichten von makroskopischen und mikroskopischen Beobachtungen, Korngrößenanalysen, Kathodolumineszenz-Mikroskopie, Bestimmung der mineralogischen Zusammensetzung (XRD, EMPA), chemische Analysen (RFA, AAS) bis zur Bestimmung von stabilen Isotopenverhältnisse (δ18O und δ13C). Weiterhin wurden die 87Sr/86Sr Verhältnisse bestimmt, gerade auch im Bezug auf die Frage, ob und in welchem Ausmaß diese Methode für die Herkunftsbestimmung von Marmoren angewendet werden kann. Desweiteren wurde die quantitative Struktur Analyse (quantitative texture analysis; QTA), welche erst seit den 1990er Jahren im Einsatz ist, zu diesem Zwecke benutzt, bzw. verbessert und verfeinert. Trotz der Tatsache, dass Marmor ein sehr verbreitetes Material in der Troas und der näheren Umgebung ist, wurden diese Rohstoffe nicht für die Herstellung von prähistorischen Marmorobjekten und kaum zur Konstruktion von hellenistischen und römischen Bauten in Troia benutzt. Die Rohstoffe der untersuchten archäologischen Objekte der prähistorischen Zeit stammen meist aus Südwest-Anatolien, neben einigen wenigen Objekten, deren Rohstoffe aus Paros und Naxos von den Kykladen stammen. Die Baumaterialien aus der hellenistischen und römischen Zeit wurden überwiegend auf der Insel Marmara gebrochen, wobei auch Rohstoffe aus Paros und Thasos vorhanden sind. Weiterhin konnte eine Marmorsorte aus dem in der näheren Umgebung gelegenen Karabiga identifiziert werden. Diese Lagerstätte liegt auf dem Festland an der gegenüberliegenden Seite des Marmara Island in der Nähe von Troia. Als ein "Nebenprodukt" der Studie wurden Entscheidungspfade entwickelt, die in erster Linie zur Bestimmung der Herkunft der trojanischen, archäologischen Materialien aus Marmor in Troia dienen, aber auch für weitere Herkunftsbestimmungen an Marmoren, insbesondere im Ost-Mediterranen Raum zur Verfügung stehen. Der Entscheidungspfad definiert eine logisch geordnete Folge von Analysenverfahren, abhängig von den Ergebnissen der vorangegangenen Erkenntnisse. Somit kann man die Probenmenge, welche für die Untersuchungen an den wertvollen archäologischen Objekten entnommen werden muss, minimieren. Darüber hinaus besteht die Möglichkeit, die anfallenden Kosten der Analytik zu senken. Andererseits werden die Chancen für eine sichere Herkunftsbestimmung deutlich verbessert. Da die untersuchten Materialien in unterschiedlicher Form zur Verfügung standen, wie zum Beispiel als Fragmente oder als Pulver, konnten nicht alle Methoden bei jeder Probe verwendet werden. Die Kathodolumineszenz-Mikroskopie oder quantitative Struktur Analyse können zum Beispiel nicht an Pulver-Proben durchgeführt werden. Um dieses Problem zu lösen, wurden die spezifischen Entscheidungspfade konstruiert

Grainautline – a Supervised Grain Boundary Extraction Tool Supported by Image Processing and Pattern Recognition

Marble provenancing is often based on stable isotopic ratios and maximum grain size (MGS). Methods for retrieving a reliable MGS value sufficiently accurate for provenancing require the observation of many grains. As this involves significant work, automation of the process is desirable. GrainAutLine, the software tool proposed in this paper is designed to find grain boundaries in a semi-automatic way and ensure high quality results. This allows marble provenancing approaches to use statistics derived from the exact boundaries, like grain-size histograms. GrainAutLine is like a very specialized drawing program featuring several sophisticated tools for boundary detection and correction. It allows the users to segment thin section, or other high resolution images including twin crystal lines and boundary discontinuities much faster than doing it manually. Segmentation results can then be exported into industry-standard shape files and further analyzed for example by GIS applications

Influence of Pre-Sintered Zirconia Surface Conditioning on Shear Bond Strength to Resin Cement

This study analyzed the shear bond strength (SBS) of resin composite on zirconia surface to which a specific conditioner was applied before sintering. After sintering of either conditioner-coated or uncoated specimens, both groups were divided into three subgroups by their respective surface modifications (n = 10 per group): no further treatment; etched with hydrofluoric acid; and sandblasted with 50 µm Al2O3 particles. Surfaces were characterized by measuring different surface roughness parameters (e.g., Ra and Rmax) and water contact angles. Half of the specimens underwent thermocycling (10,000 cycles, 5–55 °C) after self-adhesive resin cement build-up. The SBSs were measured using a universal testing machine, and the failure modes were analyzed by microscopy. Data were analyzed by nonparametric and parametric tests followed by post-hoc comparisons (α = 0.05). Conditioner-coated specimens increased both surface roughness and hydrophilicity (p < 0.01). In the non-thermocycled condition, sandblasted surfaces showed higher SBSs than other modifications, irrespective of conditioner application (p < 0.05). Adhesive fractures were commonly observed in the specimens. Thermocycling favored debonding and decreased SBSs. However, conditioner-coated specimens upon sandblasting showed the highest SBS (p < 0.05) and mixed fractures were partially observed. The combination of conditioner application before sintering and sandblasting after sintering showed the highest shear bond strength and indicated improvements concerning the failure mode

Optical characterization of translucent stone subject to degradation

Marble is an aesthetically appealing and thermodynamically ‘cool’ building material. However, when subject to weathering, marble building facade elements undergo surface degradation that result in changes to appearance and optical properties. These changes impact both the aesthetics and the thermal characteristics of the marble. This chapter highlights an experimental approach for the characterization of these changes, and numerical simulations for studying the corresponding impact on building energy performance when marble is used as an envelope finishing layer. Optical characteristics studied include gloss, solar reflectance, transmittance and absorbance. Changes in the optical characteristics of marble are used to assess the effect of degradation on it’s thermal properties