title: Interpretation of star test pattern images.
abstract: The star test pattern image contains a large amount of information about the focus OTF which is not presently used. A mathematical analysis of these images for the special case of separable and symmetrical focal spots is presented. Circular blur loci are identified and their changes over the imaging field are described. Harmonic distortion and its application are described. Sources of measurement error are discussed.
mesh_terms: D008962:Models, Theoretical; D055585:Physical Phenomena; D010825:Physics; D011859:Radiography / Q000592:standards*; D013679:Technology, Radiologic; D014965:X-Rays