Edge Locator Edge Magnitude expresses the strength of a potential edge. The (green) magnitude curve, represents magnitude values across the region of interest. Potential edges must have a mag- nitude greater than the upper threshold, or lower than the lower threshold. See the following figure. Interpreting the Magnitude Threshold in the display area l All peaks on the edge magnitude curve that fall between the two red magnitude threshold lines are not considered. l All peaks on the edge magnitude curve that are above the upper threshold or below the lower threshold are considered as potential edges.
l Sometimes unwanted edges, such as those corresponding to shadows, have mag- nitude values CLOSE to those of valid edges. When possible, do NOT use the mag- nitude threshold to reject such edges because in some images, lighting variations may cause edges of interest to also fall below the threshold. Instead, use polarity and pos- ition constraints that are not affected by lighting variations from one image to another. Edge Constraint Editor This tool uses a form for defining the constraints. To set constraints, from the object editor: 1. Select Configuration > Properties > Search Parameters Click Search Parameters to select it. 2. Click the browse icon ( ). The following window opens.
ACEUser's Guide, 3.6.x, 18316-000 Rev A Page 473