Scan Direction: Determines whether the tool will scan for an edge from top to bottom, left to right, right to left, or bottom to top.
Polarity: Determines whether to measure a dark or light object with respect to the background. Light to Dark Edges searches for edges that transition from a light background to a dark object. Dark to Light Edges searches for edges that transition from a dark background to a light object. Any Edge searches for edges of any polarity.
Sharpness: Determines the sharpness of the edge. Very Sharp Edges (+/-1) calculates gradients by looking 1 pixel before and 1 pixel after the analysis pixel. Sharp Edges (+/-2) calculates gradients by looking 2 pixels before and 2 pixels after the analysis pixel. Blurry Edges (+/-3) calculates gradients by looking 3 pixels before and 3 pixels after the analysis pixel. Very Blurry Edges (+/-4) calculates gradients by looking 4 pixels before and 4 pixels after the analysis pixel.
Straightness: Filters which edge points are used by the line fit algorithm as shown in the diagrams below. Extra Straight only uses the points that are within +/- 0.10 pixels of the line, and discards the others. This may result in a failure to find the edge if it is not perfectly straight. Rough will use all points that are within +/- 2.75 pixels of the line. This is useful for finding normal edges that are not perfectly straight. Testing has shown that Rough produces the best results for most applications.
Edge Strength: The Measure Tool provides a gradient plot to assist with the setting of the edge threshold. The plot shows you how strong the transitions from dark to light or light to dark (gradients) are within the tool’s region of interest. The plot is calculated down the center of the ROI, left-to-right when measuring width, top-to-bottom when measuring height, and at the user-defined angle when measuring angle. A red horizontal line shows where the current threshold is set. Use the slider to adjust the threshold to an optimum value.
Nominal Angle: Set the expected angle measurement in degrees. (Range: -270.0 to 270.0)
+/- Angle Tolerance: Set the range the angle can vary from the nominal angle in degrees. (Range: 0 to 180.0)
See the Image Pre-Processing section.