Part-to-whole Registration of Histology and MRI using Shape Elements

Image registration between histology and magnetic resonance imaging (MRI) is a challenging task due to differences in structural content and contrast. Too thick and wide specimens cannot be processed all at once and must be cut into smaller pieces. This dramatically increases the complexity of the problem, since each piece should be individually and manually pre-aligned. To the best of our knowledge, no automatic method can reliably locate such piece of tissue within its respective whole in the MRI slice, and align it without any prior information. We propose here a novel automatic approach to the joint problem of multimodal registration between histology and MRI, when only a fraction of tissue is available from histology. The approach relies on the representation of images using their level lines so as to reach contrast invariance. Shape elements obtained via the extraction of bitangents are encoded in a projective-invariant manner, which permits the identification of common pieces of curves between two images. We evaluated the approach on human brain histology and compared resulting alignments against manually annotated ground truths. Considering the complexity of the brain folding patterns, preliminary results are promising and suggest the use of characteristic and meaningful shape elements for improved robustness and efficiency.Comment: Paper accepted at ICCV Workshop (Bio-Image Computing

The structure of manganese dioxide-hydrogen insertion compounds and some related stability studies

Six synthetic manganese dioxides (coded SBPA, Faradiser WSZ, IBA no.14, IBA no.19, R2 and Faradiser M) covering the range of crystal structures exhibited by battery active materials were studied by XRD (X-Ray Diffraction) and FTIR (Fourier Transform Infra-Red) spectroscopy when H was inserted with organic reductants. Initial x-ray diffraction patterns (i.e. before H insertion) indicated a structural series, the γ-γt-MnO2 series. where γ-MnO2 designates the phase defined by de Wolff's intergrowth model. This model described γ-MnO2 as a random alternation of two types of layers derived from the known structures of the minerals ramsdellite and pyrolusite. γ-MnO2 may be characterised by one parameter, p, the pyrolusite type layer fraction. p=0 corresponds to ramsdellite whereas p=1 corresponds to pyrolusite. The additional structural defect responsible for the γ-γt-MnO2 series was found to be that of microtwinning in accordance with the model proposed by Pannetier et al. Material SBPA possessed a low degree of microtwinning with p=0.204±O.OO5 whereas typical battery active manganese dioxides IBA no.19 and R2 possessed x-ray diffraction patterns consistent with a high degree of microtwinning and p-0.2. The other materials, except Faradiser M, displayed x-ray diffraction patterns intermediate between those of SBPA and IBA no. 19/R2. Faradiser M possessed a high degree of microtwinning but with p-0.7. The most H inserted compounds (i.e. of composition MnOOH1.0) also formed an analogous structural series. the δ-δt-MnOOH series. δ-MnOOH may be described as a random alternation of two types of layers derived from the known structures of the minerals groutite and manganite which are reduced isostructural derivatives of ramsdellite and pyrolusite. δ-MnOOH was successfully analyzed for the concentration of (presumed) manganite type layer defects (m) in an analogous manner to that required to determine p, which confirmed the existence of reduced intergrowth structures. m was found to be less than p unless the H insertion reaction temperature was lowered (-2°C) in which case m=p. This was consistent with the observed precipitation of small amounts of γ-MnOOH when H was inserted with chemical reductants in non-aqueous solvents. The level of H insertion may be represented by the formula r in MnOOHr, where -0.1≤r≤1.0 (r starts at a value greater than zero due to the non-stoichiometry of battery active materials). H insertion into EMD (Electrodeposited Manganese Dioxide) R2 led to approximate isotropic lattice expansion in the H insertion region 0.11≤r≤0.80. This observation was consistent with a homogeneous solid state reduction with formation of a solid solution in which H+ and e- were mobile. In the region 0.80≤r≤1.01'new' non-moving peaks emerged characteristic of the final product while the original lines continued to move. The line shift indicated anisotropic lattice expansion. The 'new' non moving peaks could not be interpreted on the basis that a new phase was emerging. An explanation for this behaviour based on the properties of the defect crystal structure of the original material has been found. It involved identification of a type of x-ray line shift characteristic of random layer structures. The effects observed were consistent with random precipitation of δ-MnOOH micro-domains within the solid solution. The 'new lines' which emerged represented a re-emergence of lines originally overlapped with other lines due to the particular effects of microtwinning. The appearance of microdomains of the end product crystallizing within the solid solution implied that H+ and e- were no longer mobile in the crystal structure but located or 'frozen' in position. The presence of 'frozen' H (i.e δ-MnOOH micro-domains) was supported by measurements of FTIR band areas at wavenumber regions where OH vibration modes occurred. The onset of OH vibration modes with increasing H insertion supported the interpretation of the x-ray patterns. Interpretation of the FTIR spectra of material SBPA indicated no OH bond formation in the H insertion region 0.068≤r≤0.35 and OH bond formation in the region 0.35≤r≤0.882. Examination of the XRD patterns indicated heterogeneous solid state reduction had occurred in the H insertion region 0.40≤r≤0.882. The onset of OH bond formation at r=0.35 was interpreted as a necessary precursor to heterogeneous reduction starting at r=OAO. Heterogeneous reduction was presumed to have occurred by H location in an outer particulate layer which propagated into the bulk. H insertion into the remaining materials was interpreted in a similar manner. That is beyond a certain r in MnOOHr H location, as indicated by OH bond formation, led to crystallization of δ-MnOOH micro-domains which either randomly precipitated in the solid solution or they associated in such a way that led to heterogeneous reduction. The r in MnOOHr at which H started to locate appeared to depend on the relative rates at which H was inserted and diffused into the solid. H location occurred at r-0.20 for Faradiser M in contrast to R2 in which it located at r=0.80. A complementary study of the stability of the H inserted compounds in 7M KOH was carried out. Results from potential measurements, x-ray diffraction and SEM were obtained. Over a period of six weeks potential measurements indicated development of a heterogeneous potential at deep H insertion levels. X-ray diffraction and SEM signified formation of δ-MnO2 and γ-MnOOH. The results confirm the proposition of Holton et al. that H inserted compounds are unstable in KOH and disproportionate into δ-MnO2 and γ–MnOOH. This work removes doubt concerning the above proposition since formation of δ-MnO2 n their work was not simply the result of instability. The H insertion level at which instability was observed appeared related to the formation of δ-MnOOH micro-domains, particularly for R2 in which instability occurred between 0.80≤r≤1.0. This coincides with the oxidation state, MnO1.6, beyond which alkaline manganese batteries cease to deliver useful power on prolonged intermittent discharge. Faradiser M possessed the largest instability region (0.48≤r≤1.0) and would, on this basis, be unsuitable for alkaline manganese batteries

Registration of histology and magnetic resonance imaging of the brain

Combining histology and non-invasive imaging has been attracting the attention of the medical imaging community for a long time, due to its potential to correlate macroscopic information with the underlying microscopic properties of tissues. Histology is an invasive procedure that disrupts the spatial arrangement of the tissue components but enables visualisation and characterisation at a cellular level. In contrast, macroscopic imaging allows non-invasive acquisition of volumetric information but does not provide any microscopic details. Through the establishment of spatial correspondences obtained via image registration, it is possible to compare micro- and macroscopic information and to recover the original histological arrangement in three dimensions. In this thesis, I present: (i) a survey of the literature relative to methods for histology reconstruction with and without the help of 3D medical imaging; (ii) a graph-theoretic method for histology volume reconstruction from sets of 2D sections, without external information; (iii) a method for multimodal 2D linear registration between histology and MRI based on partial matching of shape-informative boundaries

Nonlocal smoothing and adaptive morphology for scalar- and matrix-valued images

In this work we deal with two classic degradation processes in image analysis, namely noise contamination and incomplete data. Standard greyscale and colour photographs as well as matrix-valued images, e.g. diffusion-tensor magnetic resonance imaging, may be corrupted by Gaussian or impulse noise, and may suffer from missing data. In this thesis we develop novel reconstruction approaches to image smoothing and image completion that are applicable to both scalar- and matrix-valued images. For the image smoothing problem, we propose discrete variational methods consisting of nonlocal data and smoothness constraints that penalise general dissimilarity measures. We obtain edge-preserving filters by the joint use of such measures rich in texture content together with robust non-convex penalisers. For the image completion problem, we introduce adaptive, anisotropic morphological partial differential equations modelling the dilation and erosion processes. They adjust themselves to the local geometry to adaptively fill in missing data, complete broken directional structures and even enhance flow-like patterns in an anisotropic manner. The excellent reconstruction capabilities of the proposed techniques are tested on various synthetic and real-world data sets.In dieser Arbeit beschäftigen wir uns mit zwei klassischen Störungsquellen in der Bildanalyse, nämlich mit Rauschen und unvollständigen Daten. Klassische Grauwert- und Farb-Fotografien wie auch matrixwertige Bilder, zum Beispiel Diffusionstensor-Magnetresonanz-Aufnahmen, können durch Gauß- oder Impulsrauschen gestört werden, oder können durch fehlende Daten gestört sein. In dieser Arbeit entwickeln wir neue Rekonstruktionsverfahren zum zur Bildglättung und zur Bildvervollständigung, die sowohl auf skalar- als auch auf matrixwertige Bilddaten anwendbar sind. Zur Lösung des Bildglättungsproblems schlagen wir diskrete Variationsverfahren vor, die aus nichtlokalen Daten- und Glattheitstermen bestehen und allgemeine auf Bildausschnitten definierte Unähnlichkeitsmaße bestrafen. Kantenerhaltende Filter werden durch die gemeinsame Verwendung solcher Maße in stark texturierten Regionen zusammen mit robusten nichtkonvexen Straffunktionen möglich. Für das Problem der Datenvervollständigung führen wir adaptive anisotrope morphologische partielle Differentialgleichungen ein, die Dilatations- und Erosionsprozesse modellieren. Diese passen sich der lokalen Geometrie an, um adaptiv fehlende Daten aufzufüllen, unterbrochene gerichtet Strukturen zu schließen und sogar flussartige Strukturen anisotrop zu verstärken. Die ausgezeichneten Rekonstruktionseigenschaften der vorgestellten Techniken werden anhand verschiedener synthetischer und realer Datensätze demonstriert

Proceedings of the Third International Mobile Satellite Conference (IMSC 1993)

Satellite-based mobile communications systems provide voice and data communications to users over a vast geographic area. The users may communicate via mobile or hand-held terminals, which may also provide access to terrestrial cellular communications services. While the first and second International Mobile Satellite Conferences (IMSC) mostly concentrated on technical advances, this Third IMSC also focuses on the increasing worldwide commercial activities in Mobile Satellite Services. Because of the large service areas provided by such systems, it is important to consider political and regulatory issues in addition to technical and user requirements issues. Topics covered include: the direct broadcast of audio programming from satellites; spacecraft technology; regulatory and policy considerations; advanced system concepts and analysis; propagation; and user requirements and applications

MS FT-2-2 7 Orthogonal polynomials and quadrature: Theory, computation, and applications

Quadrature rules find many applications in science and engineering. Their analysis is a classical area of applied mathematics and continues to attract considerable attention. This seminar brings together speakers with expertise in a large variety of quadrature rules. It is the aim of the seminar to provide an overview of recent developments in the analysis of quadrature rules. The computation of error estimates and novel applications also are described

Generalized averaged Gaussian quadrature and applications

A simple numerical method for constructing the optimal generalized averaged Gaussian quadrature formulas will be presented. These formulas exist in many cases in which real positive GaussKronrod formulas do not exist, and can be used as an adequate alternative in order to estimate the error of a Gaussian rule. We also investigate the conditions under which the optimal averaged Gaussian quadrature formulas and their truncated variants are internal