ABSTRACT
Computed tomography (CT) images of the human lungs show intensity variations that form certain repeated patterns, also referred to as texture. Some of these variations are due to noise and artifacts, but others are due to properties of the imaged tissue. Abnormal lung tissue can often be distinguished from healthy lung tissue based on its texture. The texture of the abnormal lung tissue depends on the type and severity of the abnormality. Three examples of regions of lung tissue extracted from CT are presented in Figure 15.1, an example of normal, healthy lung tissue in Figure 15.1(a) and two examples of abnormal lung tissue, in this case emphysema, in Figures 15.1(b) and 15.1(c). The normal lung tissue exhibits a noisy, gray pattern with thin, bright structures, which are mainly vessels and airway walls. The abnormal lung tissue is in this case characterized by black blobs, due to missing lung tissue, of varying sizes within the normal appearing tissue.
