Edge Detector

Detects edges in grayscale images.

Main Tab

The following controls are available on the Main tab.

• Step Name—Name to give the step.
• Reposition Region of Interest—When enabled, the step dynamically repositions the region of interest based on a coordinate system you built in a previous step.
• Reference Coordinate System—Coordinate system to which you want to link the region of interest.

Edge Detector Tab

The following controls are available on the Edge Detector tab.

• Edge Detector

  Simple Edge Tool	Finds step edges along a selected path based on a threshold of the grayscale values along the path. The Simple Edge Tool can return the first, both the first and the last, or all the edges found along the path.
  Advanced Edge Tool	Finds edges along a path defined in the image. A kernel operator is applied to the search region to detect edges in the image.

• Look For

  First Edge	Finds and labels only the first edge along the line selected with the ROI tool.
  First & Last Edge	Finds and labels only the first and last edge along the line selected with the ROI tool.
  All Edges	Finds and labels all edges along the line selected with the ROI tool.
  Best Edge	Finds the strongest edge in the search region.

Advanced Edge Tool Controls

The following controls are available when the Edge Detector control is set to Advanced Edge Tool.

• Edge Polarity

  All Edges	Searches for all edges.
  Rising Edges	Searches for rising edges.
  Falling Edges	Searches for falling edges.

• Interpolation Type

  Zero Order	Rounds to the nearest integral edge location.
  Bilinear	Uses bilinear interpolation to compute the edge location.
  Bilinear Fixed	Uses the fixed-point computation of bilinear interpolation to determine the edge location.

• Kernel Size—Specifies the size of the edge detection kernel.
• Width—Specifies the number of pixels averaged perpendicular to the search direction to compute the edge profile strength at each point along the search ROI.
• Min Edge Strength—Specifies the minimum edge strength required for a detected edge.
• Edge Strength Profile—Plots the variations of intensity along the selected ROI.
• Edges Found—Number of edges found along the selected ROI according to the parameters you set.

Simple Edge Tool Controls

The following controls are available when the Edge Detector control is set to Simple Edge Tool.

• Level Type

  Absolute Value	Specifies the threshold level in pixel values.
  Relative Value	Specifies the threshold level as a percentage of the intensity range found along the ROI path.

• Threshold Level—Specifies the intensity level, expressed either in pixel values or as a percentage, that you expect to constitute an edge in the image. For example, when you set Absolute Value to 128, an edge occurs when there is a transition from below 128 to above 128.
• Line Profile—Plots the variations of intensity along the selected ROI.
• Edges Found—Number of edges found along the selected ROI according to the parameters you set.