Sökning: "bias field correction"

Visar resultat 1 - 5 av 7 avhandlingar innehållade orden bias field correction.

  1. 1. Contributions to deep learning for imaging in radiotherapy

    Författare :Attila Simkó; Joakim Jonsson; Tommy Löfstedt; Anders Garpebring; Tufve Nyholm; Veronika Cheplygina; Umeå universitet; []
    Nyckelord :MEDICIN OCH HÄLSOVETENSKAP; MEDICAL AND HEALTH SCIENCES; deep learning; medical imaging; radiotherapy; artefact correction; bias field correction; contrast transfer; synthetic CT; reproducibility;

    Sammanfattning : Purpose: The increasing importance of medical imaging in cancer treatment, combined with the growing popularity of deep learning gave relevance to the presented contributions to deep learning solutions with applications in medical imaging.Relevance: The projects aim to improve the efficiency of MRI for automated tasks related to radiotherapy, building on recent advancements in the field of deep learning. LÄS MER

  3. 2. Vision Beyond the Fovea: Evaluation and Stimuli Properties

    Författare :Abinaya Priya Venkataraman; Linda Lundström; Hema Radhakrishnan; KTH; []
    Nyckelord :NATURVETENSKAP; NATURAL SCIENCES; Peripheral vision; Visual optics; Optical correction; Orientation; Stimulus extent; Moving stimulus; Contrast sensitivity; Visual acuity; Central vision loss; Myopia; Biological Physics; Biologisk fysik;

    Sammanfattning : This research is about evaluating vision in the periphery. Peripheral vision is of fundamental importance in the performance of our everyday activities. The aim of this thesis is to develop methods suitable for the evaluation of peripheral vision and to assess how different visual functions vary across the visual field. LÄS MER

  4. 3. Error reduction strategies for quantitative PET with focus on hybrid PET/MRI

    Författare :Elin Wallstén; Anne Larsson; Jan Axelsson; Katrine Riklund; Ronald Boellaard; Umeå universitet; []
    Nyckelord :MEDICIN OCH HÄLSOVETENSKAP; MEDICAL AND HEALTH SCIENCES; Positron emission tomography; PET; PET MR; PET MRI; medical imaging; partial-volume effect; attenuation correction; radiofysik; radiation physics;

    Sammanfattning : Positron Emission Tomography (PET) is an important tool for detection, staging and follow-up in a wide range of diseases, including cancer and neurological disorders. As a functional imaging tool, PET can visualize biological processes, where positron emitting radioactive isotopes are connected to molecules with different functions in the body. LÄS MER

  5. 4. Analyses and Application of Ambient Seismic Noise in Sweden : Source, Interferometry, Tomography

    Författare :Hamzeh Sadeghisorkhani; Ólafur Gudmundsson; Ari Tryggvason; Roland Roberts; Frederik Tilmann; Uppsala universitet; []
    Nyckelord :NATURVETENSKAP; NATURAL SCIENCES; Seismic interferometry; Ambient noise; Surface wave; Wave propagation; Inverse theory; Sweden; Geofysik med inriktning mot seismologi; Geophysics with specialization in Seismology;

    Sammanfattning : Ambient seismic noise from generation to its application for determination of sub-surface velocity structures is analyzed using continuous data recordings from the Swedish National Seismic Network (SNSN). The fundamental aim of the thesis is to investigate the applicability of precise velocity measurements from ambient noise data. LÄS MER

  7. 5. Diffusion-encoded MRI for assessment of structure and microcirculation : Aspects of q-space imaging and improved IVIM modelling

    Författare :Anna Scherman Rydhög; Lund Medicinsk strålningsfysik; []
    Nyckelord :;

    Sammanfattning : Diffusion and perfusion MRI are valuable methods for investigating the microstructure and viability of tissue. One pure diffusion study was included in this thesis, with the purpose of studying microstructure and carrying out size estimations with the q-space diffusion imaging method. LÄS MER