ABSTRACT
A number of investigators have developed experimental techniques based on the Rose model to evaluate object detectability at the threshold of human visibility in a medical image. One commonly used method, known as contrast-detail (C-D) curve analysis (Figure 7.1) is based on a graph that relates the threshold contrast necessary to perceive an object in an image as a function of object diameter. Larger objects can be visualized at a lower contrast, while smaller objects require a higher contrast to be visualized. Therefore, if the threshold contrast is displayed on the vertical axis and detail (or object size) on the horizontal axis, the C-D curve starts at the upper left corner (high contrast, small detail) and declines asymptotically toward the lower right corner (low contrast, large detail) in the shape of a hyperbola.
