Search for dissertations about: "Iterative reconstruction algorithms"

Showing result 1 - 5 of 16 swedish dissertations containing the words Iterative reconstruction algorithms.

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

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

    Abstract : 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. READ MORE

  4. 2. Algebraic Reconstruction Methods

    Author : Touraj Nikazad; Tommy Elfving; Constantin Popa; Linköpings universitet; []
    Keywords : NATURVETENSKAP; NATURAL SCIENCES; iterative methods; image reconstruction; ART; Cimmino; Kaczmarz; Landweber; sequential iteration; simultaneous iteration; block iteration; semi-convergence; relaxation parameters; stopping rules; discrepancy principle; Numerical analysis; Numerisk analys;

    Abstract : Ill-posed sets of linear equations typically arise when discretizing certain types of integral transforms. A well known example is image reconstruction, which can be modeled using the Radon transform. After expanding the solution into a finite series of basis functions a large, sparse and ill-conditioned linear system occurs. READ MORE

  5. 3. The Use of Landweber Algorithm in Image Reconstruction

    Author : Touraj Nikazad; Tommy Elfving; George Baravdish; Linköpings universitet; []
    Keywords : NATURVETENSKAP; NATURAL SCIENCES; convex feasibility; projection methods; simultaneous algorithms; iterative methods; stopping rules; semi-convergence; Numerical analysis; Numerisk analys;

    Abstract : Ill-posed sets of linear equations typically arise when discretizing certain types of integral transforms. A well known example is image reconstruction, which can be modelled using the Radon transform. After expanding the solution into a finite series of basis functions a large, sparse and ill-conditioned linear system arises. READ MORE

  6. 4. Iterative Filtered Backprojection Methods for Helical Cone-Beam CT

    Author : Johan Sunnegårdh; Michael Felsberg; Michel Defrise; Linköpings universitet; []
    Keywords : TEKNIK OCH TEKNOLOGIER; ENGINEERING AND TECHNOLOGY; Iterative reconstruction; filtered backprojection; regularization; cone-beam CT; Medical engineering; Medicinsk teknik;

    Abstract : State-of-the-art reconstruction algorithms for medical helical cone-beam Computed Tomography (CT) are of type non-exact Filtered Backprojection (FBP). They are attractive because of their simplicity and low computational cost, but they produce sub-optimal images with respect to artifacts, resolution, and noise. READ MORE

  7. 5. Low kilovoltage computed tomography to reduce contrast medium dose in patients at risk of acute kidney injury

    Author : Fredrik Holmquist; Lund Diagnostisk radiologi; []
    Keywords : MEDICIN OCH HÄLSOVETENSKAP; MEDICAL AND HEALTH SCIENCES; Computed tomography; Image quality; Radiation dosimetry; contrast medium induced nephropathy; Iterative reconstruction algorithms;

    Abstract : Background: Patients with reduced renal function may be at risk of contrast medium-induced acute kidney injury (CI-AKI) following intravenous iodine contrast medium (CM) enhanced computed tomography (CT). Reducing the CM dose may reduce this risk. READ MORE