ABSTRACT
IN Chapter 5, we presented a number of techniques for visualizing scalarfields. Three-dimensional (volumetric) scalar fields are a particular case poses additional problems and difficulties for visualization. Such datasets are common in many application domains. In particular, in medical sciences, there are several types of data-acquisition processes that generate volumetric datasets, such as computed tomography (CT), magnetic resonance imaging (MRI), positron emission tomography (PET), single photon emission computed tomography (SPECT), and ultrasound scans. Such techniques can be used to record anatomical information, such as the shape and composition of various tissues in the human body, but also functional information, such as the concentration of various substances in living tissues (functional MRI). Moreover, these techniques can be used to record still, time-independent scans as well as scans that reveal the dynamic processes in the human body, such as the flow of blood or motion of muscles. As we have seen, such three-dimensional scalar fields can be visualized using techniques such as slice planes and isosurfaces. However, such techniques are limited in showing only a subset of the entire scalar volume.
