### Width Measure Tool Parameters

See the Width Measure Tool Parameters section for details.

- ROI: Set the start point coordinates (x, y), width, height, and tilt angle of the region of interest (ROI).

- Measurement Direction: Select the measurement direction.
  [Width Measurement]: Measure the width.
  [Height Measurement]: Measure height.

- 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.

- Threshold: Set the Edge Strength threshold. 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.

- Distance Type: Determines how the distance between two edges of the object should be calculated. Point to Line Distance measures the perpendicular distance from the first edge’s center point to the second edge’s best fit line. Choose Point to Line Distance when measuring between parallel lines. Point to Point Distance measures the distance from the center points of two edges. Choose Point to Point Distance when measuring between non-parallel lines, or when you want the rotation of the lines to be ignored.

- Lower/Upper Tolerance: Lower and upper tolerance in pixels.