Sökning: "forward projection"

Visar resultat 1 - 5 av 15 avhandlingar innehållade orden forward projection.

  1. 1. Combining analytical and iterative reconstruction in helical cone-beam CT

    Författare :Johan Sunnegårdh; Gösta Granlund; Per-Erik Danielsson; Michel Defrise; Linköpings universitet; []
    Nyckelord :TEKNIK OCH TEKNOLOGIER; ENGINEERING AND TECHNOLOGY; cone-beam tomography; forward projection; image reconstruction; iterative reconstruction; ordered subsets; regularization; WFBP; Signal processing; Signalbehandling;

    Sammanfattning : Contemporary algorithms employed for reconstruction of 3D volumes from helical cone beam projections are so called non-exact algorithms. This means that the reconstructed volumes contain artifacts irrespective of the detector resolution and number of projection angles employed in the process. LÄS MER

  3. 2. Neuromodulation shapes interneuron communication in the mouse striatum

    Författare :Matthijs Constantijn Dorst; Karolinska Institutet; Karolinska Institutet; []
    Nyckelord :;

    Sammanfattning : A proper understanding of cognition relies on detailed knowledge about the functional connectivity within and between brain areas. The striatum is generally regarded as the input structure to the basal ganglia, a group of subcortical nuclei that have been demonstrated to be involved in motor function and reward, amongst other functions. LÄS MER

  4. 3. Inverse Problems in Tomography and Fast Methods for Singular Convolutions

    Författare :Fredrik Andersson; Matematik LTH; []
    Nyckelord :NATURVETENSKAP; NATURAL SCIENCES; Mathematics; Matematik; Unequally spaced FFT; Integral transforms; Singular integrals; Lippmann?Schwinger equation; Helmholtz equation; Inverse problems; Fast Gauss transform; Fast summation; Convolution; Radon transform; Tomography;

    Sammanfattning : There are two, partially interlaced, themes treated in this thesis; inverse problems of tomographic type and fast and accurate methods for the application of convolution operators. Regarding the first theme, the inverse problem of Doppler tomography is considered and the Doppler moment transform is introduced for that purpose. LÄS MER

  5. 4. Model Order Reduction with Rational Krylov Methods

    Författare :K. Henrik A. Olsson; Axel Ruhe; Volker Mehrmann; KTH; []
    Nyckelord :NATURVETENSKAP; NATURAL SCIENCES; Model order reduction; dual rational Arnoldi; rational Krylov; moment matching; eigenvalue computation; stability analysis; heat exchanger model; Numerical analysis; Numerisk analys;

    Sammanfattning : Rational Krylov methods for model order reduction are studied. A dual rational Arnoldi method for model order reduction and a rational Krylov method for model order reduction and eigenvalue computation have been implemented. It is shown how to deflate redundant or unwanted vectors and how to obtain moment matching. LÄS MER

  7. 5. Problems and experiments in cone-beam tomography

    Författare :Jan Eriksson; Stefan Challer; Linköpings universitet; []
    Nyckelord :;

    Sammanfattning : Two-dimensional detectors for cone-beam exposure are now introduced in medical as well as industrial computer tomography. This thesis starts with a review of basic 2D reconstruction algorithms and the first proposal for cone-beam tomography due to Feldkamp et al.Exact reconstruction is possible only if complete projection data are avail­ able. LÄS MER