Quantitative Texture Analysis Research Articles

Quantitative texture analysis from powder-like electron diffraction data

The textures of an Al thin film and of α-MnS nanocrystals deposited on a carbon film grid have been analysed using powder electron diffraction. For each sample a series of powder electron diffraction patterns tilted with respect to two orthogonal axes were collected, to adapt to this type of data the texture analysis procedures commonly used in synchrotron X-ray transmission geometry. Both pattern sets have been analysed with the Rietveld procedure embedded in the softwareMAUD. The fit is satisfactory with agreement factors of 7.03% for the Al film and 3.42% for α-MnS and reveals in both cases a (111) preferred orientation with a pronounced cylindrical symmetry. The (111) and (100) pole figures, plotted in terms of multiples of random distribution (m.r.d.), show a fairly strong lattice preferred orientation in the Al thin film and a stronger one in the deposited α-MnS nanocrystals, with maxima, for the (111) pole figures, of 8.8 and 19.7 m.r.d., respectively.

Contrasted textural and taphonomic properties of high-energy wave deposits cemented in beachrocks (St. Bartholomew Island, French West Indies)

This study investigates the preservation potential of high-energy wave deposits by beachrocks located along shores contrastingly exposed to storms. In order to discriminate between clast populations originating in different formational and depositional conditions, namely fair-weather vs. extreme wave conditions, the applicability of quantitative textural and taphonomic analyses of sand- to boulder-sized sediments was evaluated using samples from beachrocks and non-cemented coarse-grained coastal deposits. The size, shape and roundness of coarse clasts were characterized by measuring axial dimensions (L, I and S), from which shape descriptors were derived. Taphonomic scores were established at macroscopic and microscopic (thin-section) scales by rating the degree of physical and biologically-mediated alteration of skeletal material. Combined with the examination of depositional morphologies and facies architectures, the procedure enables characterization of fair-weather and extreme wave-generated deposits, and provides criteria to distinguish between single-event deposits and reworked material resulting from the coalescence of sediments produced during multiple events. The distinction of single short-lived event deposits from those reflecting long-term reworking is crucial for correctly interpreting similar deposits in the geological record and evaluating the historical hazard along coastlines. Site-dependent controls such as the nature of available sediments, the geomorphology of coastal depositional settings, and the tectono-climatic context proved to be important for interpreting the origin of the high-energy wave deposits studied here. In the ongoing debate on the signatures of tsunamigenic and storm sediments in fringing coastal settings, the present study demonstrates that one promising research direction is the use of multiple sedimentological criteria to characterize event materials, including their morphology and taphonomy, combined with the precise characterization of site-specific controls.

Calculating anisotropic physical properties from texture data using the MTEX open-source package

Abstract This paper presents the background for the calculation of physical properties of an aggregate from constituent crystal properties and the texture of the aggregate in a coherent manner. Emphasis is placed on the important tensor properties of 2nd and 4th rank with applications in rock deformation, structural geology, geodynamics and geophysics. We cover texture information that comes from pole figure diffraction and single orientation measurements (electron backscattered diffraction or EBSD, electron channelling pattern, Laue pattern, optical microscope universal-stage). In particular, we provide explicit formulae for the calculation of the averaged tensor from individual orientations or from an orientation distribution function (ODF). For the latter we consider numerical integration and an approach based on the expansion into spherical harmonics. This paper also serves as a reference paper for the mathematical tensor capabilities of the texture analysis software MTEX, which is a comprehensive, freely available MatLab toolbox that covers a wide range of problems in quantitative texture analysis, for example, ODF modelling, pole figure to ODF inversion, EBSD data analysis and grain detection. MTEX offers a programming interface which allows the processing of involved research problems as well as highly customizable visualization capabilities; MTEX is therefore ideal for presentations, publications and teaching demonstrations.

Generalized Kearns texture factors and orientation texture measurement

A generalization of the Kearns texture factors is presented. Mathematical relationships are derived that relate the generalized texture factors to other measures commonly used in quantitative texture analysis. In addition, values of the generalized texture factors for random orientation texture, numerical bounds for the texture factors, and estimates for experimental uncertainty are given. Kearns’ method for measuring texture factors from θ − 2 θ X-ray diffraction scans is extended for use in measuring higher order texture factors. A comparison of generalized texture factors measured through three common experimental techniques is presented.

Magma Solidification Processes beneath Kilauea Volcano, Hawaii: a Quantitative Textural and Geochemical Study of the 1969-1974 Mauna Ulu Lavas

Kilauea volcano is a very intensively studied, active basaltic magmatic system and thus represents an ideal location to study magma solidification processes in a natural environment. Understanding solidification is important in refining models of magma chamber dynamics and its detailed study may improve our knowledge of magma system evolution. In this study magma solidification processes are examined and quantified using samples from the 1969–1974 Mauna Ulu (MU) rift eruption. We have collected major and trace element whole-rock data plus in situ olivine compositions, along with crystal size distribution data on 11 lava samples. The observed whole-rock chemical variation was partly produced by olivine addition within the Kilauea edifice. At least two distinct olivine populations are inferred from quantitative textural analysis: (1) a 3–40-year-old population characterized by a low crystal density, greater crystal length and flatter slopes of the crystal size distributions (CSDs); (2) a 1·5–15-year-old population marked by a high density of smaller crystals and steep CSD slopes. The range in olivine composition suggests that all these crystals grew from a range of different magmas, probably closely related by crystal fractionation. The ubiquitous presence of deformed olivine crystals shows that population 1 reflects a component that must have mostly originated by disruption of a deformed cumulate. This antecrystic olivine population represents an earlier-coarsened and aggregated, cumulate-forming magma component. In contrast, the phenocrystic population 2 represents a late magma component formed in the summit magma storage region. Our results are consistent with the hypothesis that the components of the MU magmas followed two different routes. The deformed-olivine-bearing magma moved along the deep basal décollement then rose through vertical pipe-like conduits under the MU rift. The undeformed-olivine-bearing magma rose via the main conduit to the summit reservoir and then moved out along the rift zone, where the magmas mixed in small chambers. The presence of narrow, reversely zoned olivine rims suggests that the mixing occurred just prior to eruption.

Crystallization and textural evolution of a closed-system magma chamber: insights from a crystal size distribution study of the Lilloise layered intrusion, East Greenland

AbstractThe recognition that postcumulus processes significantly modify primary textures in layered mafic intrusions has thrown into question many early observations on which classical crystallization theories are based. Petrographic observations combined with quantitative textural analysis of samples from various stratigraphic levels of the Lilloise intrusion, East Greenland, demonstrate that postcumulus textural modification of cumulates, formed during the solidification of a closed system magma chamber, may be detected. Crystal size distribution (CSD) measurements of Lilloise cumulates and the resulting CSD profiles are compared to predicted theoretical closed system CSD profiles. Similarities between the measured CSD profiles and published predicted CSD profiles support Lilloise magma evolving in a closed system chamber and indicate that primary crystallization processes can be distinguished using quantitative textural techniques. Textural coarsening driven by syn-magmatic deformation is suggested to be the dominant postcumulus process affecting CSD plot morphology. CSD slope values and profiles (plot shapes) remain relatively constant for a given liquidus mineral (particularly olivine and clinopyroxene), so that the number of phases on the liquidus at any one time affects mineral modal abundances. As a result, CSDs generally exhibit overall smaller grainsizes and progressively lower nucleation densities at higher levels in the intrusion.

Fabric Development in a Middle Devonian Intraoceanic Subduction Regime: The Careón Ophiolite (Northwest Spain)

A Middle Devonian suprasubduction zone ophiolite, the Careón Unit (northwest Spain), displays amphibolite‐facies ductile deformation fabrics related to the onset of the Rheic Ocean closure. Two different fabrics, an early high‐T foliation and a subsequent lower‐T foliation, each of which characterized by distinct deformation mechanisms, have been identified in two distinct crustal‐scale shear zones of the same ophiolitic thrust sheet. Combined quantitative texture analysis by electron backscattered diffraction and time‐of‐flight neutron diffraction, were carried out on the shear zones and correlated with micro‐ and macrostructural data. The results indicate that the regional lineation and shear zone kinematics (east‐west, top‐to‐the‐east) represent fabrics developed essentially during the intraoceanic subduction of the Rheic Ocean, and their orientation may be considered a reference vector for convergence models in this part of the Variscan belt.

Brittle plus plastic deformation of gypsum aggregates experimentally deformed in torsion to high strains: quantitative microstructural and texture analysis from optical and diffraction data

Abstract This contribution presents a quantitative microstructural analysis of a polycrystalline aggregate of gypsum, deformed in torsion ( T =70–90 °C) at γ (shear strain) ranging from 0 to 4.82. Quantitative microstructural analysis is used to compare the evolution of microstructures observed by optical microscope with those obtained from analysis of X-ray and neutron diffraction data. This analysis shows that during experimental deformation, gypsum accommodated strain by brittle and plastic deformation mechanisms, developing Riedel-like microfaults with plastic foliations and crystallographic preferred orientation (CPO). The relations of microstructures show that with increasing strain, the Riedel systems start from R planes with an angle of ≈30° to the Imposed Shear Plane. This angle decreases (5°–15°) when strain increases, and Y planes develop. Quantitative texture analysis (QTA) shows that S-foliations start developing at low γ and maintain their orientation up to high γ, and that the most active slip system is the (010) along normal to (100) and the [001]-axis. Shape preferred orientation (SPO) of gypsum does not coincide with the theoretical orientation as it does not decrease with increasing strain. This discrepancy is explained by the role of the brittle shear planes that impose a back rotation to gypsum. No brittle to plastic transition occurs. But both plastic and brittle structures contemporaneously accommodate and localize strain.

Quantitative Texture Analysis and Transesophageal Echocardiography to Characterize the Acute Myocardial Contusion

Quantitative Texture Analysis and Transesophageal Echocardiography to Characterize the Acute Myocardial Contusion

Texture analysis of a turbostratically disordered Ca-montmorillonite

Turbostratic disorder, consisting in a disorder in which different layers have different rotations with respect to an axis, is commonly found in montmorillonite. The effect of this kind of disorder on diffraction profiles is significant and must be taken into account, especially in quantitative phase analysis. The effect of the turbostratic disorder in textured materials has never been investigated. In the present work, we have developed a strategy to perform quantitative texture analysis on turbostratically disordered Ca-montmorillonite aggregates that were uniaxially compressed. Synchrotron diffraction images were analyzed with a Rietveld method and disordered and ordered models are compared. The method proved to be reliable and ready for further applications.

The modified component method for calculation of orientation distribution function from pole figures

The main problem of the quantitative texture analysis is discussed. The sharp texture of nanocrystalline magnesium is under investigation. The well-known harmonic (Roe–Bunge) method of texture determination does not give good results for the materials with low sample symmetry. The robust component fit method for the determination of the orientation distribution function from the set of incomplete X-ray pole figures is used in this work. A unique and reliable solution is achieved.

Texture research of metals and rocks on the KSN-2 neutron diffractometer

From the industrial point of view the research activities of the Laboratory of Neu- tron Diffraction (Faculty of Nuclear Sciences and Physical Engineering CTU Prague) are concentrated to the quantitative texture analysis based on the ODF (orientation distribution function). We have developed the experimental and data treatment procedures for this type research. The texture experiments were carried out on the neutron diffractometer KSN-2 using the TG-1 texture goniometer. This diffraction device offers good intensity with wave- lengths in the range 0.095 to 0.141 nm. Experimental data in form of the pole figures or the inversion pole figures were treated by means of these codes: popLA, TODF-N, MAUD, GSAS. Quantitative texture analysis by means neutron diffraction data were used on the investigation of the many samples of the technically interesting materials. For example, we have determined the texture parameters on the oriented Si steel sheets and rock materials (limestone test samples).

X-ray Quantitative Texture Analysis onHelix Aspersa Aspera(Pulmonata) Shells Selected or Not for Increased Weight

X-ray Quantitative Texture Analysis (QTA) results are examined for the outer aragonitic shell layers of Helix aspersa aspersa (Müller, 1774) to probe the relevance of the approach to non-flat surfaces. Two sets of H. aspersa aspersa were studied, for a total of 29 samples. Quantitative texture analysis showed that although the nature of the texture present was roughly constant, the textural strength varied significantly among specimens because of biologically inherited surface irregularities. A statistical analysis showed that textural strength exhibited larger standard deviations for snails selected for greater shell weight than for control snails. The H. aspersa aspersa aragonite texture is the same as observed in previous studies, with <110> shell growth directions. This texture causes elastic behavior of the mineral part of the shell, which accommodates moderate shear and compression. We furthermore determine that the colored bands at the shell surface were aligned with the <020> crystal directions.

Using Individual Spectra Simulation for the Study of Pole Figures Errors

Crystallographic texture is described by pole figures. In this paper, we continue to study experimental pole figure errors. In other words it can be named pole figure measurement errors. These errors are connected with the experimental procedure and do not depend on any further computations. In our previous works it was shown that the qualitative behaviour of pole figure measurement errors is similar to peak width determination errors. To check this conclusion a set of diffraction spectra were measured for Mg + 4.5%Al + 1%Zn sample on the spectrometer for quantitative texture analysis (SKAT) at FLNP, JINR, Dubna. Then we simulated the individual spectra and used these spectra for the pole figure extraction and the pole figure error determination. Such simulation enabled to confirm conclusions concerning the main role of the peak width determination error in the pole figure error. Additionally, we simulated individual spectra using model pole figures and extracted pole figures and pole figures errors from those spectra. For this case we also confirmed the same qualitative behaviour of pole figure measurement errors and peak width determination errors. The model pole figures were calculated on the basis of normal distributions.

Microstructure and texture analysis of YBCO thick film with peritectic growth on unoriented silver substrate

YBCO textured thick film was prepared by direct peritectic growth method. Microstructure of the film was characterized. Electron backscattered diffraction (EBSD) technique was applied to the film for quantitative texture analysis. The main difficulty in resolving the orientation of YBCO pseudo-cubic structure was investigated. Automated orientation mapping was performed on YBCO thick film. Local texture was presented in the form of orientation maps. Misorientation distribution and crystal growth characterization in the YBCO thick film were revealed. Large domains with well-aligned YBCO grains were formed. Each domain presented clear in-plane and out-plane textures.

A theoretical solution to MAP‐EM partial volume segmentation of medical images

Voxels near tissue borders in medical images contain useful clinical information, but are subject to severe partial volume (PV) effect, which is a major cause of imprecision in quantitative volumetric and texture analysis. When modeling each tissue type as a conditionally independent Gaussian distribution, the tissue mixture fractions in each voxel via the modeled unobservable random processes of the underlying tissue types can be estimated by maximum a posteriori expectation-maximization (MAP-EM) algorithm in an iterative manner. This paper presents, based on the assumption that PV effect could be fully described by a tissue mixture model, a theoretical solution to the MAP-EM segmentation algorithm, as opposed to our previous approximation which simplified the posteriori cost function as a quadratic term. It was found out that the theoretically-derived solution existed in a set of high-order non-linear equations. Despite of the induced computational complexity when seeking for optimum numerical solutions to non-linear equations, potential gains in robustness, consistency and quantitative precision were noticed. Results from both synthetic digital phantoms and real patient bladder magnetic resonance images were presented, demonstrating the accuracy and efficiency of the presented theoretical MAP-EM solution.

Quantitative Texture Analysis and Transesophageal Echocardiography to Characterize the Acute Myocardial Contusion

Myocardial contusion (MC) is a common injury following blunt chest trauma without any specific symptoms.Several techniques such as electrocardiogram, estimation of myocardial band fraction of creatine phosphokinase, chest radiography and the scintiscanning missed efficiency to characterize the MC.Another technique based on transesophageal echocardiography [TEE] allows to visualize the structures of the heart with a good spatial resolution.We postulated that the quantitative texture analysis of regional image texture in two- dimensional [2D] TEE echocardiograms would be an accurate method to differentiate normal from abnormal myocardial wall.This preliminary experimental study demonstrated the feasibility of the proposed technique.

Coregistered FDG PET/CT-Based Textural Characterization of Head and Neck Cancer for Radiation Treatment Planning

Coregistered fluoro-deoxy-glucose (FDG) positron emission tomography/computed tomography (PET/CT) has shown potential to improve the accuracy of radiation targeting of head and neck cancer (HNC) when compared to the use of CT simulation alone. The objective of this study was to identify textural features useful in distinguishing tumor from normal tissue in head and neck via quantitative texture analysis of coregistered 18F-FDG PET and CT images. Abnormal and typical normal tissues were manually segmented from PET/CT images of 20 patients with HNC and 20 patients with lung cancer. Texture features including some derived from spatial grey-level dependence matrices (SGLDM) and neighborhood gray-tone-difference matrices (NGTDM) were selected for characterization of these segmented regions of interest (ROIs). Both K nearest neighbors (KNNs) and decision tree (DT)-based KNN classifiers were employed to discriminate images of abnormal and normal tissues. The area under the curve (AZ) of receiver operating characteristics (ROC) was used to evaluate the discrimination performance of features in comparison to an expert observer. The leave-one-out and bootstrap techniques were used to validate the results. The AZ of DT-based KNN classifier was 0.95. Sensitivity and specificity for normal and abnormal tissue classification were 89% and 99%, respectively. In summary, NGTDM features such as PET Coarseness, PET Contrast, and CT Coarseness extracted from FDG PET/CT images provided good discrimination performance. The clinical use of such features may lead to improvement in the accuracy of radiation targeting of HNC.

Mechanical properties of textured ceramics from muscovite–kaolinite alternate layers

An organized network of mullite anisotropic crystals embedded in a silico-aluminate matrix material is obtained at interfaces of sintered alternate layers of muscovite and kaolinite minerals. The nucleation and growth of mullite anisotropic crystals occur preferentially along the muscovite basal planes through topotactic reaction with the high temperature form of muscovite. Simultaneously to structural transformations, dehydroxylation of muscovite induces an exfoliation process, which is temperature and time dependent. The kinetics of this process was controlled using an appropriate thermal cycle and uniaxial load. During sintering, the control of mullite size mainly depends in temperature and the addition of a small quantity of low-temperature liquid phase also favors the growth of mullite. But liquid induces the weakening of the organization degree of the mullite network. Quantitative texture analysis (QTA) and SEM were used to characterize microstructural characteristics. Flexural strength, Young modulus and fracture toughness are closely related to size and organization degree of the mullite network. In general, mullite length favors the increase of strength and fracture toughness. But a high organization degree of the mullite network favors the occurrence of interconnected crystals and increases mechanical properties.

Discrimination of annealed and dynamic fabrics: Consequences for strain localization and deformation episodes of large-scale shear zones

Large-scale shear zones are often characterized by long lasting deformation with complex strain localization behavior. Based on a drill core across polymineralic carbonate mylonites of the Doldenhorn nappe (Helvetic Alps, Switzerland), the present study uses spatially resolved microstructural variations to discriminate unambiguously deformation microstructures from annealed ones, to infer the deformation mechanisms, and to reconstruct the strain localization history. These goals require quantitative microstructural and textural analyses of sample suites in sections across the shear zone. Particularly the occurrence of two distinct Zener trends, i.e., the relationship between grain size and volume fraction of matrix and second phase grains, allows for the identification of annealed from dynamic microstructures. The data presented here indicate that continued shearing after peak metamorphic conditions and during exhumation-induced cooling resulted in progressive strain localization at the base of the shear zone, while the inactive parts of the formerly high temperature shear zone were progressively overprinted by annealing.