Normalized edge intensity vs. time (minutes) for loaded (solid line) and unloaded (dashed line) ROIs shown in fig. 5.

<p>Typically, the noise threshold of the edge intensity algorithm is somewhere between R<sub>I</sub> [0.1, 0.2]. Note the large differences in degradation time between loaded and unloaded ROIs when R<sub>I</sub>  = 0.1 or R<sub>I</sub>  = 0.2 are used as end points (110 or 120 min. respectively).</p>