Figure 7 shows the two image related classes, Image and StereoImage. The Image class is a conceptual image as defined in Section 1.4. It records the image's dimensions (
x 
and the colour depth), the raw image data and possibly
an identifier, used to tag images for correlation (as described in Section 2.3.1).
The Image class really exists to serve StereoImage, which is basically comprised of two Image objects. A StereoImage may have a left Image only, a right Image only or both a left and right Image. Exactly which Images it has at any point depends on the context, and can be tested with the HasLeft(), HasRight() and HasBoth() boolean-valued methods.
