Fig 8.

A sample change detection image, demonstrating the detection of changes which are subtle but which involve a large area. (a) T1 Post-Gd Time 0, (b) FLAIR Time 0, (c) T1 Post-Gd Time 1, (d) FLAIR Time 1, (e) Unthresholded color change map (which is dark because the change, while omnipresent, is of quite small membership). (f) Simple thresholded color change map, (g) adaptive thresholded change map. Note that the simple threshold has completely missed the change, but has not removed all noise, whereas the adaptive threshold technique eliminates virtually all noise and retains a large region of subtle change. The color scheme is shown in Figure 7; the region shown consists of an area of development of subtle enhancement.