How to Find Edges (Legacy)

Note  This step is deprecated. The replacement step is Find Edges, which incorporates the functionality of the original Find Edges step and provides additional functionality.

Main Tab

1. In the Step Name control, enter a descriptive name for the step.
2. Choose one of the following methods to specify the region of interest for the step:
   • Create a new region of interest.
     1. Select Constant from the Region of Interest listbox.
     2. Select a tool from the menu toolbar that matches the type of region of interest you want to specify.
     3. Draw a region of interest on the image.

        Tip  Hold down the <Ctrl> key to specify a region of interest containing several contours using the same or different tools. Hold down the <Shift> key to draw a horizontal or vertical line.

   • Select a previously defined region of interest from the Region of Interest listbox.

   When you specify a region of interest, the step automatically tries to locate edge points along the region. The located edges are marked on the image with blue and red squares.

3. Verify that the Reposition Region of Interest option is enabled if you want to link the region of interest specified in this step to a previously defined coordinate system.

   Link the region of interest to a coordinate system if the position of the object under inspection changes from image to image, and you need to adjust the position of the region of interest to match the new location of the object.

Settings Tab

4. If the automatically located edges correspond to the edges you expected to find, proceed to step 5. Otherwise, disable the Auto Setup control and manually adjust the edge location parameters.
   1. Choose the type of edges you want to detect from the Look For control. You can choose from All Edges, First Edge Only, and First & Last Edge Only.
   2. Select the polarity of the edges you want to locate.
   3. If the Edge Strength Profile contains peaks that correspond to all the edges you want to find, adjust the yellow edge strength line so that it lies slightly below the top of the shortest edge peak.

      If the Edge Strength Profile does not contain peaks that correspond to all the edges, adjust the Smoothing and Steepness controls until the peaks appear.

Limits Tab

5. Set the minimum and/or maximum number of edges you want locate.