X-ray computed tomography for fast and non-destructive multiple pearl inspection

Rosc, J.; Hammer, Vera M. F.; Brunner, Roland

doi:10.1016/j.csndt.2016.08.002

Cited by 6 publications

(3 citation statements)

References 11 publications

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“…therefore, the traditional identification methods have their limitations to some extent [1,2] . Among the current detection methods, X-ray radiography and X-CT methods face certain challenges in pearl inspection, including low spatial resolution, high cost, and the potential for radiation, which may lead to a decrease in the value of pearls [3][4][5] . Electron microscopy (SEM) has a high spatial resolution.…”

Section: Introductionmentioning

confidence: 99%

Polarization-sensitive OCT-based pearl feature detection

Cao,

Li,

et al. 2023

Third International Computing Imaging Conference (CITA 2023)

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In this study, a detection system based on Polarization-Sensitive Optical Coherence Tomography (PS-OCT) using Mueller Matrix Optical Coherence Tomography (MM-OCT) was developed. By employing PS-OCT technology, the system was able to fully detect all sixteen elements of the Mueller matrix. By comparing the intensity element M00 among the sixteen elements of the Mueller matrix, the texture structure of the pearl layers could be observed. This allowed for differentiation between freshwater and saltwater pearls, identification of genuine and fake pearls, detection of internal flaws in pearls, and differentiation between nucleated and non-nucleated pearls. The study also involved the labeling of connected regions in binary images, where pixels within the same connected region were assigned the same label. The labeled images were displayed to facilitate more intuitive qualitative analysis, and quantitative analysis was performed using gray-level co-occurrence matrices. Subsequently, pearl layer pixels were extracted from multiple angles in the images, and the thickness of the pearl layer was calculated using the extracted pixels and axial resolution. Finally, detection and classification of unknown pearls were conducted, yielding results consistent with the actual outcomes. The measured thickness results after sectioning matched the calculated results, providing evidence for the feasibility of the experimental method proposed in this study.

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Section: Introductionmentioning

confidence: 99%

Polarization-sensitive OCT-based pearl feature detection

Cao,

Li,

et al. 2023

Third International Computing Imaging Conference (CITA 2023)

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“…However, in some cases, radiographs are not sufficient for a certain identification. For this reason, the tomographic technique has recently been applied to gems and pearls [18][19][20][21], providing valuable information on the origin of the pearls through the visualization of their internal structure and the study of the X-ray absorption coefficient variation of the images in a non-invasive and non-destructive way (taking into account the preciousness of some of these objects).…”

Section: Introductionmentioning

confidence: 99%

X-ray Micro-Tomography as a Method to Distinguish and Characterize Natural and Cultivated Pearls

Vigorelli

Croce

Angelici³

et al. 2021

Condensed Matter

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Digital radiography and computed tomography are two fundamental diagnostic techniques in different fields of research, including cultural heritage studies and gemmology. The application of these physical methods of investigation has gained considerable importance as they are non-invasive techniques. The presented work has been mainly focused on micro-tomographic analysis. The project is concerned with the study of natural and cultivated pearls in order to develop an investigation methodology for the analysis, distinction and characterization of different types of pearls, some of them belonging to different precious jewels from private collections. The investigations, carried out on a total of 22 heterogeneous types of pearls, allowed us to establish their origin (natural or cultivated) or to confirm/deny if a hypothesis was already expressed, and as well to highlight the cultivation methodology used case by case. Furthermore, it was possible to ascertain how large and varied the market for cultured pearls is nowadays and how difficult is, in some particular cases, to ascertain their attribution to a certain origin.

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“…However, for decades by far the most important approach to identifying natural and cultured pearls has been X-radiography and, in more recent years, micro-CT (Anderson, 1932;Farn, 1986;Kennedy, 1998;Scarratt et al, 2000;Schlüter et al, 2005;Hänni, 2006;Strack, 2006;Wehrmeister et al, 2008;Sturman, 2009;Karampelas et al, 2010;Krzemnicki et al, 2010;Cartier and Krzemnicki, 2013;Rosc et al, 2016). Both methods enable the visualization and interpretation of internal features in pearls such as cavities, ring structures, dehydration fissures and bead structures.…”

Section: Introductionmentioning

confidence: 99%

Simultaneous X-Radiography, Phase-Contrast and Darkfield Imaging to Separate Natural from Cultured Pearls

Krzemnicki¹,

Hanser²,

Revol³

2017

Journ of Gemm

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The separation of natural from cultured pearls is mainly based on the interpretation of their internal structures, which traditionally have been visualized by X-radiography and more recently by X-ray computed microtomography (micro-CT). In this study, the authors present a new analytical approach using a grating interferometer, which simultaneously generates an X-radiograph, a phase-contrast image and a small-scale scattering or darkfield image. The latter two additional images provided by this technique offer detailed and complementary information, as they are especially sensitive for visualizing tiny material inhomogeneities in pearls such as fissures, organic layers and cavity structures. Using seven selected natural and cultured pearl samples and a strand of non-beaded freshwater cultured pearls, the authors demonstrate that this new analytical approach offers versatile and rapid pearl identification possibilities, especially as it is possible to analyse not only single loose pearls but also entire strands and necklaces. Compared to micro-focus digital radiography and micro-CT, certain limitations in resolution still remain with the described prototype setups, and as such this new methodology should be considered a helpful complementary technique to the classical radiography of pearls.

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X-ray computed tomography for fast and non-destructive multiple pearl inspection

Cited by 6 publications

References 11 publications

Polarization-sensitive OCT-based pearl feature detection

Polarization-sensitive OCT-based pearl feature detection

X-ray Micro-Tomography as a Method to Distinguish and Characterize Natural and Cultivated Pearls

Simultaneous X-Radiography, Phase-Contrast and Darkfield Imaging to Separate Natural from Cultured Pearls

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