Sökning: "ring artifacts"

Hittade 4 avhandlingar innehållade orden ring artifacts.

  1. 1. High-resolution biomedical phase-contrast tomography

    Författare :William Twengström; Hans Hertz; Anna Burvall; Marco Stampanoni; KTH; []
    Nyckelord :NATURVETENSKAP; NATURAL SCIENCES; MEDICIN OCH HÄLSOVETENSKAP; MEDICAL AND HEALTH SCIENCES; x-ray; x-ray imaging; biomedical; phase contrast; tomography; zebrafish; coronary artery; virtual histology; ring artifacts; phase retrieval; mummy; Fysik; Physics;

    Sammanfattning : Improved three-dimensional biomedical imaging can give a better understanding of tissue structure, growth and diseases. Most present imaging techniques that provide cellular spatial resolution are based on visible or infrared light. These methods cannot image deeper than a millimeter into tissue. LÄS MER

  3. 2. On perfusion estimation using ultrasound

    Författare :Tomas Jansson; Avdelningen för Biomedicinsk teknik; []
    Nyckelord :TEKNIK OCH TEKNOLOGIER; ENGINEERING AND TECHNOLOGY; Instrumentation technology; Speckle; Artifacts; Perfusion; Ultrasound; Doppler; Mät- och instrumenteringsteknik;

    Sammanfattning : This thesis has the main focus on ways to improve the blood perfusion estimate, as obtained from a continuous wave Doppler system. Earlier studies have shown large temporal variations in the detected perfusion estimate, due to speckle. LÄS MER

  4. 3. Spectral Computed Tomography with a Photon-Counting Silicon-Strip Detector

    Författare :Mats Persson; Mats Danielsson; Hans Bornefalk; Jiang Hsieh; KTH; []
    Nyckelord :NATURVETENSKAP; NATURAL SCIENCES; TEKNIK OCH TEKNOLOGIER; ENGINEERING AND TECHNOLOGY; Photon-counting; silicon-strip detector; spectral computed tomography; ring artifacts; fluence rate; basis material decomposition; sub-pixel information; Fysik; Physics;

    Sammanfattning : Computed tomography (CT) is a widely used medical imaging modality. By rotating an x-ray tube and an x-ray detector around the patient, a CT scanner is able to measure the x-ray transmission from all directions and form an image of the patient’s interior. LÄS MER

  5. 4. Image analysis for volumetric characterisation of microstructure

    Författare :Maria Axelsson; Sveriges lantbruksuniversitet; Sveriges lantbruksuniversitet; []
    Nyckelord :TEKNIK OCH TEKNOLOGIER; ENGINEERING AND TECHNOLOGY;

    Sammanfattning : Digital image analysis provides methods for automatic, fast, and reproducible analysis of images. The main contribution of this thesis is new image analysis methods for volumetric characterisation of microstructure with application in the field of material science. LÄS MER