PHYS1008 Lecture Notes - Lecture 9: Dynamic Range, Spatial Frequency, Digital Image Processing
Document Summary
The most important characteristics of radiographic image quality are: spatial resolution, contrast resolution, noise, artefacts. Resolution is the ability to image two separate objects and visually distinguish one from the other. Spatial resolution: ability to image small objects that have high subject contrast. The fundamental concept of spatial frequency does not refer to size but to the lien pair. A line pair is a black line on a light background. One line pair consists of the line and an interspace of the same width as the line. Spatial frequency relates the number of line pairs in a given length, expressed as cm or mm. the unit spatial frequency as used in medical imaging describes line pair per mm (lp/mm) An imaging system with higher spatial frequency has better spatial resolution. Contrast resolution: ability to distinguish anatomical structures of similar subject contrast. The principal descriptor for contrast resolution is grey-scale (dynamic range)
