TY - JOUR A1 - Osterloh, Kurt T1 - Computertomographie und Bildverarbeitung für die industrielle Radiologie, ein internationales Symposium PY - 2003 SN - 1616-069X SN - 0948-5112 VL - 86 SP - 12 EP - 14 PB - Deutsche Gesellschaft für Zerstörungsfreie Prüfung CY - Berlin AN - OPUS4-2787 LA - deu AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Osterloh, Kurt A1 - Ewert, Uwe A1 - Pries, A.R. T1 - Interaction of albumin with the endothelial cell surface KW - Electron spin resonance KW - Molecular mobility KW - Endothelial surface layer PY - 2002 SN - 0002-9513 VL - 283 SP - H398 EP - H405 PB - American Physiological Society CY - Bethesda, Md. AN - OPUS4-1980 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Osterloh, Kurt A1 - Ewert, Uwe T1 - Bedrohung durch Minen, können zerstörungsfreie Prüfmethoden zur Beseitigung beitragen? PY - 2002 SN - 1616-069X SN - 0948-5112 PB - Deutsche Gesellschaft für Zerstörungsfreie Prüfung CY - Berlin AN - OPUS4-2009 LA - deu AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Beckmann, Jörg A1 - Osterloh, Kurt A1 - Malitte, Hans-Joachim A1 - Ewert, Uwe T1 - Mobile Durchstrahlungsprüfung - Untersuchungen kampfstoffverdächtiger Objekte mit der Speicherfolientechnik PY - 2002 SN - 0025-5300 VL - 44 IS - 10 SP - 414 EP - 419 PB - Carl Hanser Verlag CY - München AN - OPUS4-2079 LA - deu AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Osterloh, Kurt T1 - Aims and objectives of the EFNDT working group: 'NDT for public safety and security' N2 - The preservation of human achievements and progress is undoubtedly a pillar of our society. This includes detecting threats in time to prevent disasters that may occur from forces of nature, defective technology, human failure or malicious intent. In this respect, there is arguably no difference between safety and security, though different institutions are involved in the regulation and control of them. However, the unifying rationale ought to result in the building of bridges between them. This is the Working Group's mission. KW - Bridging technical safety and public security PY - 2011 U6 - https://doi.org/10.1784/insi.2011.53.6.331 SN - 0007-1137 VL - 53 IS - 6 SP - 331 EP - 333 PB - British Institute of Non-Destructive Testing CY - Northampton AN - OPUS4-25065 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Osterloh, Kurt A1 - Bücherl, T. A1 - Lierse von Gostomski, C. A1 - Zscherpel, Uwe A1 - Ewert, Uwe A1 - Bock, S. T1 - Filtering algorithm for dotted interferences N2 - An algorithm has been developed to remove reliably dotted interferences impairing the perceptibility of objects within a radiographic image. This particularly is a major challenge encountered with neutron radiographs collected at the NECTAR facility, Forschungs-Neutronenquelle Heinz Maier-Leibnitz (FRM II): the resulting images are dominated by features resembling a snow flurry. These artefacts are caused by scattered neutrons, gamma radiation, cosmic radiation, etc. all hitting the detector CCD directly in spite of a sophisticated shielding. This makes such images rather useless for further direct evaluations. One approach to resolve this problem of these random effects would be to collect a vast number of single images, to combine them appropriately and to process them with common image filtering procedures. However, it has been shown that, e.g. median filtering, depending on the kernel size in the plane and/or the number of single shots to be combined, is either insufficient or tends to blur sharp lined structures. This inevitably makes a visually controlled processing image by image unavoidable. Particularly in tomographic studies, it would be by far too tedious to treat each single projection by this way. Alternatively, it would be not only more comfortable but also in many cases the only reasonable approach to filter a stack of images in a batch procedure to get rid of the disturbing interferences. The algorithm presented here meets all these requirements. It reliably frees the images from the snowy pattern described above without the loss of fine structures and without a general blurring of the image. It consists of an iterative, within a batch procedure parameter free filtering algorithm aiming to eliminate the often complex interfering artefacts while leaving the original information untouched as far as possible. KW - Neutron KW - Radiography KW - Tomography KW - Filtering KW - Evaluation KW - NECTAR PY - 2011 U6 - https://doi.org/10.1016/j.nima.2011.01.107 SN - 0168-9002 SN - 0167-5087 VL - 651 IS - 1 SP - 171 EP - 174 PB - Elsevier B.V. CY - Amsterdam AN - OPUS4-24917 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Osterloh, Kurt A1 - Fratzscher, Daniel A1 - Schwabe, A. A1 - Schillinger, B. A1 - Zscherpel, Uwe A1 - Ewert, Uwe T1 - Radiography and partial tomography of wood with thermal neutrons N2 - The effective high neutron scattering absorption coefficient of hydrogen (48.5 cm²/g) due to the scattering allows neutrons to reveal hydrocarbon structures with more contrast than X-rays, but at the same time limits the sample size and thickness that can be investigated. Many planar shaped objects, particularly wood samples, are sufficiently thin to allow thermal neutrons to transmit through the sample in a direction perpendicular to the planar face but not in a parallel direction, due to increased thickness. Often, this is an obstacle that prevents some tomographic reconstruction algorithms from obtaining desired results because of inadequate information or presence of distracting artifacts due to missing projections. This can be true for samples such as the distribution of glue in glulam (boards of wooden layers glued together), or the course of partially visible annual rings in trees where the features of interest are parallel to the planar surface of the sample. However, it should be possible to study these features by rotating the specimen within a limited angular range. In principle, this approach has been shown previously in a study with fast neutrons [2]. A study of this kind was performed at the Antares facility of FRM II in Garching with a 2.6×107/cm² s thermal neutron beam. The limit of penetration was determined for a wooden step wedge carved from a 2 cm×4 cm block of wood in comparison to other materials such as heavy metals and Lucite as specimens rich in hydrogen. The depth of the steps was 1 cm, the height 0.5 cm. The annual ring structures were clearly detectable up to 2 cm thickness. Wooden specimens, i.e. shivers, from a sunken old ship have been subjected to tomography. Not visible from the outside, clear radial structures have been found that are typical for certain kinds of wood. This insight was impaired in a case where the specimen had been soaked with ethylene glycol. In another large sample study, a planar board made of glulam has been studied to show the glued layers. This study shows not only the limits of penetration in wood but also demonstrates access to structures perpendicular to the surface in larger planar objects by tomography with fast neutrons, even with incomplete sets of projection data that covers an angular range of only 90° or even 60°. KW - Neutron computed tomography KW - Limited angle tomography KW - Wood KW - Annual rings PY - 2011 U6 - https://doi.org/10.1016/j.nima.2011.02.095 SN - 0168-9002 SN - 0167-5087 VL - 651 IS - 1 SP - 236 EP - 239 PB - Elsevier B.V. CY - Amsterdam AN - OPUS4-24918 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Osterloh, Kurt T1 - Der EFNDT WG5 Workshop in Berlin Köpenick vom 22. bis 24. Oktober 2012 PY - 2012 UR - http://www.dgzfp.de/Portals/24/Zeitung/Ausgaben/Zeitung132.pdf#page=10 SN - 1616-069X SN - 0948-5112 VL - 132 SP - 12 PB - Deutsche Gesellschaft für Zerstörungsfreie Prüfung CY - Berlin AN - OPUS4-27549 LA - deu AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Osterloh, Kurt A1 - Bücherl, T. A1 - Zscherpel, Uwe A1 - Ewert, Uwe T1 - Image recovery by removing stochastic artefacts identified as local asymmetries N2 - Stochastic artefacts are frequently encountered in digital radiography and tomography with neutrons. Most obviously, they are caused by ubiquitous scattered radiation hitting the CCD-sensor. They appear as scattered dots and, at higher frequency of occurrence, they may obscure the image. Some of these dotted interferences vary with time, however, a large portion of them remains persistent so the problem cannot be resolved by collecting stacks of images and to merge them to a median image. The situation becomes even worse in computed tomography (CT) where each artefact causes a circular pattern in the reconstructed plane. Therefore, these stochastic artefacts have to be removed completely and automatically while leaving the original image content untouched. A simplified image acquisition and artefact removal tool was developed at BAM and is available to interested users. Furthermore, an algorithm complying with all the requirements mentioned above was developed that reliably removes artefacts that could even exceed the size of a single pixel without affecting other parts of the image. It consists of an iterative two-step algorithm adjusting pixel values within a 3 × 3 matrix inside of a 5 × 5 kernel and the centre pixel only within a 3 × 3 kernel, resp. It has been applied to thousands of images obtained from the NECTAR facility at the FRM II in Garching, Germany, without any need of a visual control. In essence, the procedure consists of identifying and tackling asymmetric intensity distributions locally with recording each treatment of a pixel. Searching for the local asymmetry with subsequent correction rather than replacing individually identified pixels constitutes the basic idea of the algorithm. The efficiency of the proposed algorithm is demonstrated with a severely spoiled example of neutron radiography and tomography as compared with median filtering, the most convenient alternative approach by visual check, histogram and power spectra analysis. KW - Data processing methods KW - Image filtering KW - Pattern recognition KW - Cluster finding KW - Calibration and fitting methods PY - 2012 U6 - https://doi.org/10.1088/1748-0221/7/04/C04018 SN - 1748-0221 VL - 7 IS - April SP - 1 EP - 14 PB - Inst. of Physics Publ. CY - London AN - OPUS4-25877 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Osterloh, Kurt A1 - Rädel, Christoph A1 - Zscherpel, Uwe A1 - Meinel, Dietmar A1 - Ewert, Uwe A1 - Buecherl, T. A1 - Hasenstab, A. T1 - Fast neutron radiography and tomography of wood N2 - Wood is the material that has accompanied the whole development of mankind in various applications, for manufacturing tools and weapons, for buildings and constructions and also as fuel. It has various appearances and is subjected to decomposing changes, so there are sufficient arguments for non-destructive testing of wooden objects in the same way as is common practice with other technologically used materials. However, even today wood is rarely tested. Moreover, artefacts of cultural heritage containing wood are rare and delicate, so dismantling these for studying purposes is undesirable. Radiological inspection technologies are the methods of choice to provide a non-destructive insight. Interrogations of a specimen with various kinds of radiation provide different answers about their internal structures. High-quality detailed images are achievable with X-rays or gamma radiation in cases where heavy metals or other dense materials are not involved. Neutrons behave complementarily; they are avidly absorbed by light elements such as hydrogen on the one hand and yet are capable of easily penetrating heavy metals on the other. This provides an alternative for X-ray radiography and tomography when material characteristics are of primary interest rather than structural details, or when shielding with plates or sleeves of heavy metal severely impedes inspections with X-ray or gamma radiation technologies. However, due to the moderating effect of wooden samples it is essential to use fast neutrons for radiography and tomography of voluminous objects. Some typical examples described here will show the difference between neutron and X-ray photon-based radiographic technologies. KW - Materialgeschichtliches KW - Vergleich zwischen Röntgen- und Neutronenradiographie PY - 2008 U6 - https://doi.org/10.1784/insi.2008.50.6.307 SN - 0007-1137 VL - 50 IS - 6 SP - 307 EP - 311 PB - British Institute of Non-Destructive Testing CY - Northampton AN - OPUS4-18034 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Osterloh, Kurt T1 - EFNDT WG5: von Antipersonenminen zur öffentlichen Sicherheit KW - Themenerweiterung PY - 2006 SN - 1616-069X SN - 0948-5112 IS - 98 SP - 28 EP - 29 PB - Deutsche Gesellschaft für Zerstörungsfreie Prüfung CY - Berlin AN - OPUS4-14169 LA - deu AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Osterloh, Kurt A1 - Wrobel, Norma A1 - Kolkoori, Sanjeevareddy T1 - EFNDT Working Group 5 - der Brückenschlag zwischen technischer und öffentlicher Sicherhheit N2 - Die Arbeitsgruppe 5 der Europäischen Föderation für Zerstörungsfreie Prüfung (EFNDT Working Group 5 'Public Security and Safety', EFNDT WG 5) verfolgt weiterhin das Ziel, organisatorisch weit auseinanderliegende Zuständigkeiten und Arbeitsgebiete zusammenzuführen, die weitgehend mit gleichen, zumindest ähnlichen Prinzipien und Methoden arbeiten. Auf der Suche nach neuen Wegen stoßen beide Seiten auf Gemeinsamkeiten. Dies gilt auch für neue Ansätze und Bewertungsmethoden von Techniken, mit denen Risiken vermindert werden sollen. Hierzu hat in Berlin ein Workshop im Oktober 2012 stattgefunden, auf dem parallele Projekte zur Container- und Frachtsicherheit zusammengeführt werden konnten. Herausgestellt wurde die Komplementarität der laufenden Projekte, gemeinsame Aspekte sollen künftig auch zusammen bearbeitet werden. Darüber hinaus wurden neue Methoden und Vorgehensweisen vorgestellt, aber auch die Sichtweise der Europäischen Kommission mit ihren Vorstellungen zu einem europäischen Markt für Sicherheitstechnik dargestellt. Angesprochen wurden bestehende und vorgeschlagene europaweite Regulierungen und das europäische Referenznetz zum Schutz kritischer Infrastrukturen (ERNCIP), welches ein Netzwerk von Laboratorien für den Test von Sicherheitstechnik zum Ziel hat. Auf technischem Sektor standen Methoden im Vordergrund, mit denen die Gesamtmenge eines Gefahrstoffes wie z. B. Sprengstoff erkannt werden kann, und nicht nur Spuren als indirekter Hinweis. Die Arbeitsgruppe konnte somit erstmalig ein neutrales Forum für parallel laufende Projekte zur öffentlichen Sicherheit zur Verfügung stellen. Die auf den Workshops 2010 bis 2012 in Berlin gehaltenen Vorträge sind auf der Webseite des EFNDT WG 5 im geschützten Bereich zu finden. Nicht alles davon ist geeignet, es der allgemeinen Öffentlichkeit zugänglich zu machen. Deshalb sind alle Vorträge aus den Workshops in einem passwortgeschützten Verzeichnis abgelegt. Die Erteilung des Passwortes erfolgt über den Convenor der Arbeitsgruppe durch die EFNDT. Eine Erweiterung dieser Struktur zu einem Austauschforum ist vorgeschlagen. Zur Teilnahme daran sind nicht nur Mitglieder in den Gesellschaften für zerstörungsfreie Prüfung eingeladen, sondern auch diejenigen, die in den Anwendungsgebieten zur öffentlichen Sicherheit tätig sind. KW - Zerstörungsfreie Prüfung (ZfP) KW - Brücke zur öffentlichen Sicherheit PY - 2013 U6 - https://doi.org/10.3139/120.110479 SN - 0025-5300 VL - 55 IS - 7-8 SP - 582 EP - 587 PB - Hanser CY - München AN - OPUS4-29327 LA - deu AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Kolkoori, Sanjeevareddy A1 - Wrobel, Norma A1 - Osterloh, Kurt A1 - Zscherpel, Uwe A1 - Ewert, Uwe T1 - Novel X-ray backscatter technique for detection of dangerous materials: application to aviation and port security N2 - Radiological inspections, in general, are the nondestructive testing (NDT) methods to detect the bulk of explosives in large objects. In contrast to personal luggage, cargo or building components constitute a complexity that may significantly hinder the detection of a threat by conventional X-ray transmission radiography. In this article, a novel X-ray backscatter technique is presented for detecting suspicious objects in a densely packed large object with only a single sided access. It consists of an X-ray backscatter camera with a special twisted slit collimator for imaging backscattering objects. The new X-ray backscatter camera is not only imaging the objects based on their densities but also by including the influences of surrounding objects. This unique feature of the X-ray backscatter camera provides new insights in identifying the internal features of the inspected object. Experimental mock-ups were designed imitating containers with threats among a complex packing as they may be encountered in reality. We investigated the dependence of the quality of the X-ray backscatter image on (a) the exposure time, (b) multiple exposures, (c) the distance between object and slit camera, and (d) the width of the slit. At the end, the significant advantages of the presented X-ray backscatter camera in the context of aviation and port security are discussed. KW - Inspection with x-rays KW - Detection of explosives KW - Compton imaging KW - Detection of defects PY - 2013 U6 - https://doi.org/10.1088/1748-0221/8/09/P09017 SN - 1748-0221 VL - 8 IS - 9 SP - P09017-1 EP - P09017-18 PB - Inst. of Physics Publ. CY - London AN - OPUS4-29329 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Kolkoori, Sanjeevareddy A1 - Wrobel, Norma A1 - Osterloh, Kurt A1 - Redmer, Bernhard A1 - Deresch, Andreas A1 - Ewert, Uwe T1 - Hochenergieradiografie - Erkennung von Einzelheiten in großen, komplexen Schichttiefen N2 - Zur Durchstrahlung großer, dichter Objekte reichen die Energien, die mit normalen Röntgenröhren erzielt werden können, ab gewissen Schichtdicken nicht mehr aus. Als hochenergetische Strahlenquellen stehen Kobalt-60 und Elektronenbeschleuniger zur Verfügung. Als Einschränkung der Hochenergieradiografie ist der geringere Kontrast besonders beim Vorhandensein leichterer Objekte umgeben von Körpern bestehend aus schweren Elementen anzusehen. Es ist daher zu erwarten, dass Objekte aus organischen Substanzen hinter dicken Schwermetallwänden oder in Bohrungen von Metallblöcken schwer zu erkennen sind. Im Unterschied zu einem Gammastrahler wie Kobalt-60 mit den beiden Spektrallinien um 1,3 MeV besitzt die Bremsstrahlung aus einem Beschleuniger einen wesentlichen Anteil an niederenergetischer Strahlung, der fließend zu höheren Energien übergeht. Es wird hier untersucht, welche Signaturen von leichten Materialien in einer Umgebung aus Schwermetall bis zu welcher Dicke und bis zu welchem Komplexitätsgrad erkennbar sind. Mit einem Betatron (JME X-ray Betatron 7,5 MeV) und einem Matrixdetektor (Perkin Elmer XRD 1621) wurden Aufnahmen von unterschiedlichen leichten Objekten angefertigt, die zunehmend in eine Umgebung aus Schwermetallen gestellt wurden. Mit unterschiedlichen Energieeinstellungen wurde untersucht, inwieweit eine Materialerkennung hinter welcher Abschirmung möglich ist. Die experimentellen Ergebnisse werden mit Simulationen verglichen, die mit einer Software zur Modellierung von Durchstrahlungsverfahren (aRTist) erzeugt wurden. Dabei wird dem Problem der Aufhärtung bei Anwendung von Bremsstrahlung Rechnung getragen. Die Ergebnisse können sowohl zur Erkennung von Fremdkörpern in Maschinen oder Pumpen als auch zur Überprüfung von Frachtladungen im Bereich der öffentlichen Sicherheit und bei Zollkontrollen dienen. KW - Hochenergieradiographie KW - Containerprüfung KW - Materialerkennung PY - 2013 U6 - https://doi.org/10.3139/120.110492 SN - 0025-5300 VL - 55 IS - 9 SP - 683 EP - 688 PB - Hanser CY - München AN - OPUS4-29057 LA - deu AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Wrobel, Norma A1 - Kolkoori, Sanjeevareddy A1 - Osterloh, Kurt T1 - Röntgenrückstreuradiografie - Eindringen statt Durchdringen, aber Bilder mit Schatten N2 - Der große praktische Vorteil der Rückstreuradiografie allgemein ist, dass kein Bilddetektor am Objekt auf der der Strahlenquelle gegenüberliegenden Seite aufgestellt werden muss. Dieses ist immer dann gegeben, wenn sich das Untersuchungsobjekt in oder an einer Wand befindet oder es so groß ist, dass eine Durchstrahlung aufgrund der zu durchdringenden Schichtdicken nicht infrage kommt. Von der üblichen Methode, das Objekt mit einem wandernden ausgeblendeten Einzelstrahl ('Bleistiftstrahl') abzutasten und die gesamte rückgestreute Strahlung großflächig zu registrieren, unterscheidet sich das hier verwendete Verfahren grundsätzlich. Das Objekt wird voll von einem (unkollimierten) Kegelstrahl angestrahlt. Das Bild wird mit einer Kamera aus absorbierendem Material (Wolfram, Blei) aufgenommen, die einen Matrixdetektor als Bildempfänger enthält. Die 'Optik' besteht aus einer besonders geformten Schlitzblende, die nach einem erweiterten Lochkameraprinzip arbeitet, das auch dickere Blendenmaterialschichten zulässt. Die voneinander unabhängige Positionierung von Kamera und Strahlenquellen erlaubt unterschiedliche Einstrahlgeometrien, die verschiedene Ergebnisbilder liefern. So erscheint ein komplexer Gegenstand vor einer rückstreuenden Wand völlig anders, als wenn er frei im Raum steht. Röntgenrückstreubilder müssen deshalb abhängig von ihrer 'Ausleuchtung' mit der Röntgenstrahlung und näheren Umgebung interpretiert werden. KW - Röntgen-Rückstreuradiographie KW - Schlitzblende KW - Variable Einstrahlgeometrie PY - 2013 SN - 0025-5300 VL - 55 IS - 9 SP - 689 EP - 693 PB - Hanser CY - München AN - OPUS4-29058 LA - deu AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Hasenstab, A. A1 - Osterloh, Kurt A1 - Ewert, Uwe T1 - Mobile Röntgenblitzröhren zum Auffinden von Holzschäden N2 - "Um Holz auf Schäden hin zu untersuchen, müssen Verfahren auch vor Ort durchführbar sein. Mit Hilfe von mobilen, tragbaren Röntgenblitzröhren und digitalen Radiografiesystemen ist dies möglich. Um die Anzeichen einer Schädigung im digitalen Röntgenbild zu erkennen, ist eine Bildbearbeitung notwendig. Hier werden die Ergebnisse von Röntgenuntersuchungen mit Blitzgeneratoren, einem digitalen Radiografiesystem auf Halbleiterbasis und einer automatisch ablaufenden Bildbearbeitung vorgestellt. Bei den Beispielen handelt es sich jeweils um eine Probe aus Nadelholz und Laubholz, die von geschädigten Bäumen und Bauwerken entnommen wurden. Dem einbaufrischen Bauteil wurden künstliche Strukturen eingebracht. Die aufgeführten Beispiele demonstrieren, wie mit transportablen Geräten innere Schäden im Holz zerstörungsfrei aufgespürt werden können." (gekürztes Autorenreferat) Schadstellen und Fäulnis in trockenen Bäumen und in trockenen Holzbalken lassen sich mit den Mitteln der digitalen Radiographie darstellen. Diese Aufnahmetechniken kommen mit geringeren Strahlendosen als bei einer herkömmlichen Filmbelichtung aus. Die Verwendung digitaler Detektoren, kombiniert mit einer PC-basierten Bildbearbeitung, erlaubt eine schnelle Auswertung vor Ort. Die automatisierte Bildfilterung gestattet eine zügige Durchführung auch ohne tiefgehende Kenntnisse in der digitalen Bildauswertung. Diese spielt hier eine tragende Rolle, wobei die in den Rohbilddaten enthaltenen relevanten Informationen gegenüber denjenigen, die im Augenblick weniger oder nicht interessieren, hervorgehoben werden. Risse werden längs der Einstrahlrichtung gut sichtbar, senkrecht dazu verlaufende allerdings wegen mangelnder Kontrastunterschiede nicht. An dieser Stelle bietet sich die Ultraschall-Echotechnik als komplementäres Verfahren an. KW - Digitale Radiographie vor Ort KW - Holzfäule KW - Bauholz KW - Holzschäden PY - 2008 SN - 0018-3881 IS - 2 SP - 1 EP - 19(?) PB - DRW-Verl. Weinbrenner CY - Leinfelden-Echterdingen AN - OPUS4-20716 LA - deu AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Osterloh, Kurt A1 - Zscherpel, Uwe A1 - Ewert, Uwe T1 - X-ray backscatter radioscopy for security applications with a novel twisted slit collimator KW - Röntgenrückstreuung KW - Kamera für hochenergetische Strahlung PY - 2009 SN - 1619-2486 IS - 10 SP - 22 EP - 25 PB - ddp Goldenbogen CY - Dresden AN - OPUS4-20711 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Osterloh, Kurt A1 - Bellon, Carsten A1 - Hohendorf, Stefan A1 - Kolkoori, Sanjeevareddy A1 - Wrobel, Norma A1 - Nusser, A. A1 - Freitag, M. A1 - Bücherl, T. A1 - Bar, D. A1 - Mor, I. A1 - Tamin, N. A1 - Weiss-Babai, R. A1 - Bromberger, B. A1 - Dangendorf, V. A1 - Tittelmeier, K. T1 - Computed tomography with X-rays and fast neutrons for restoration of wooden artwork N2 - The objects of this investigation were sculptures taken from a ca. three hundred years old baroque epitaph of a church in Tonning, a town in Northern Germany. Around 1900 it was found in a disastrous state heavily damaged by wood-worm. At that time, the whole artwork was treated with the tar extract carbolineum as a remedy. Nowadays, this substance has been identified as carcinogenic, and its presence can be perceived by its stench and visually at certain spots on the surface where it has penetrated the covering paint. A gold-painted sculpture of a massive wooden skull was interrogated with X-rays and fast neutrons to investigate the internal distribution of the carbolineum. The X-ray tomography, with its excellent spatial resolution revealed galleries left over from the worm infestation in the outer areas and cracks in the central region. The golden color coating appeared as a thick and dense layer. In comparison the tomography with fast neutrons, though being of lower resolution and yet unresolved artefacts revealed sections of slightly different densities in the bulk of the wood. These differences we attribute to the differences in the distribution of the impregnant in the wood, visible due to its higher hydrogen content making it less transparent for neutrons. T2 - WCNR-10 - 10th World conference on neutron radiography CY - Grindelwald, Switzerland DA - 05.10.2014 KW - Computed tomography KW - Neutron radiology KW - Conservation of wooden artwork PY - 2015 U6 - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:kobv:b43-323050 SN - 1875-3892 VL - 69 SP - 472 EP - 477 PB - Elsevier B.V. CY - Amsterdam AN - OPUS4-32305 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Nusser, A. A1 - Osterloh, Kurt A1 - Freitag, M. A1 - Simon, S. ED - Reiche, I. T1 - Analyse von mit Carbolineum belastetem Kulturgut und modellhafte Erprobung konservatorischer Dekontaminierung N2 - The baroque epitaph Reyer (1704) at the St. Laurentius church in Tönning was treated with carbolineum as a wood preservation agent in 1903. The subsequent constant migration of carbolineum through the layers of paint to the surface has had a detrimental effect on the aesthetic appearance of the epitaph. Carbolineum is an oily, water-insoluble, flammable, dark brown mixture of coal tar oil components. Due to its content of polycyclic aromatic hydrocarbons (PAH), which are classified as carcinogenic and harmful to the environment, the use of carbolineum has been forbidden. The aim of the project is to develop an exemplary Conservation treatment (hat will reduce the toxic contents of the historical wooden object. The new method should be applicable to similar objects that are also contaminated with carbolineum. The historic carbolineum was identified by the GC-MS method and the X-Ray computed tomography revealed the biological wood damage and previous restoration measures. Several decontamination methods such as the extraction with supercritical C02, with dichloromethane vapour/fluids, with 1,3-dioxolane or with petrol ether by vaccum impregnation were investigated. This project is founded by the Deutsche Bundesstiftung Umwelt (DBU). KW - Kulturgut aus Holz KW - Holzschutz KW - Computertomographie PY - 2014 SN - 0344-5089 VL - 22 SP - 77 EP - 82 PB - Rathgen-Forschungslabor CY - Berlin AN - OPUS4-32516 LA - deu AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Osterloh, Kurt A1 - Jaenisch, Gerd-Rüdiger T1 - Rare events - a probability approach or an ill-posed problem? N2 - Rare events are understood to be events occurring once in a while but with dramatic consequences. Their occurrence cannot be predicted precisely, only a probability might be estimated, for example from past experiences. However, it might be rather misleading to attempt to describe them by distribution curves that apply for frequent or repeated observations, such as the Gaussian bell shape. Alternative distributions have been introduced to characterise the intervals at which a certain event may occur. It is the aim of technical safety and public security to prevent adverse events. Detectable indications that are typical for their course and are observable have to be identified before an incident occurs. Since they should be characteristic for such cases, they themselves also constitute rare events. The problem encountered in any detection system is that nothing is perfect. As in medical diagnostics, true indications may be missed or false test responses may pretend to be something that does not exist. Balancing missed indications with false positive calls is achieved with the aid of the so-called receiver operating characteristics (ROC). However, with the aid of Bayes’ inference it can be shown that identifying signs of a rarely occurring indication is like looking for a needle in a haystack, even with an excellent detection Approach with a low miss rate and an even lower probability of false calls. The inclusion of additionally available information may lead to a more effective search strategy. When employing imaging methods for detecting flaws or illicit items, the identification of rare indications can be impeded by blurring noise or overlapping items. The identification of the features sought can be supported by including information on their typical characteristics by regularisation algorithms. The strategy of such an approach is demonstrated in a simplified example with a plain geometric figure (circle) corrupted with structural noise. The shape of the original figure was clearly recovered. In general, search strategies should aim at an indication typical for the event to be prevented; otherwise, alternative approaches have to be considered, including, perhaps, serendipity. KW - Rare events KW - Bayes statistics KW - Ill-posed problems PY - 2016 U6 - https://doi.org/10.1784/insi.2016.58.1.46 SN - 0007-1137 VL - 58 IS - 1 SP - 46 EP - 51 PB - British Institute of Non-Destructive Testing CY - Northampton AN - OPUS4-35312 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Osterloh, Kurt A1 - Röhrs, S. A1 - Schwabe, A. A1 - Radujcovic, S. A1 - Bücherl, T. A1 - Dangendorf, V. A1 - Zscherpel, Uwe A1 - Reiche, I. A1 - Nüsser, A. ED - Zscherpel, Uwe ED - Kasperl, S. T1 - Elucidating the distribution of organic consolidants in wood by Neutron Tomography N2 - While the absorption of X-rays and gamma radiation is determined by the Z-number of the elements a specimen is composed of, it is the hydrogen making an effective contrast with neutron imaging. As a consequence, interrogating with neutrons presents a suitable tool to study the distribution of organic consolidants in materials such as wood as encountered in impregnated wooden artworks. Four different examples of objects are presented here to demonstrate the potential of neutron CT: 1) small wooden pieces of ship wrecks (< 2 cm thickness) interrogated with cold neutrons (0.5 meV at the ANTARES facility of the FRM II in Garching) to demonstrate the potential and the limitation of using low energy neutrons, 2) a wooden statue soaked with carbolineum (fission neutrons 1.8 MeV at the NECTAR facility of the FRM II), 3) a smaller wooden figure of a skull heavily soaked with carbolineum so it was too tight for the fission neutrons used before with accelerator neutrons (broad range about 5.5 MeV at the PTB in Braunschweig) and 4) pieces of charred wood to study the impregnation with a consolidant (NECTAR, FRM II). With the exception of the last example, all results have been combined with X-ray tomography (BAM 8.3 in Berlin). In the case of the charred wood specimens (example 4) the density histograms of the neutron tomography results were compared with those obtained from untreated references. The observed gain in specific density of the soaked specimens corresponded with an increase of specific weight. All results obtained so far showed distinct distribution patterns attributable to structural peculiarities or organic consolidants providing valuable support for subsequent restoration works. T2 - International symposium on digital industrial radiography and computed tomography DIR2019 CY - Fürth, Germany DA - 02.07.2019 KW - Neutron Imaging KW - Cold to fast neutron testing KW - Tomography of wood samples KW - Art restauration PY - 2019 U6 - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:kobv:b43-505326 UR - https://www.ndt.net/search/docs.php3?id=24740 SN - 1435-4934 VL - 24 IS - 11 SP - 1 EP - 8 PB - NDT.net CY - Kirchwald AN - OPUS4-50532 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER -