How to Match Colors

Template Selection Interface

1. Draw a region of interest around an area of the image that contains the reference color or colors. This region becomes the color template.
2. Click OK to accept the template.

Main Tab

3. In the Step Name control, enter a descriptive name for the step.
4. 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.

        Note  Hold down the <Ctrl> key to draw additional regions of interest.

   • Select a previously defined region of interest from the Region of Interest listbox.
5. 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.

Template Tab

6. Select the Color Sensitivity to set how detailed you want the color matching algorithm to represent the color template.
7. Select a Saturation Threshold value that distinguishes colors of the same hue value adequately enough for your application needs.
8. Enable the Ignore White control if you want the step to ignore the white content of the color template. Enable the Ignore Black control if you want the step to ignore the black content of the color template.

Settings Tab

9. Set the Minimum Match Score that a region of interest can have to be valid. Refer to the Matches table to determine this score. The table lists the match score and Pass/Fail status of each region you defined. You can use the Matches table to choose a Minimum Match Score value that finds the number of matches you request but excludes unwanted matches.

Limits Tab

10. Set the minimum and/or maximum number of matches you expect to find.

Tip  Use the Logic Calculator step or Calculator step to make an inspection decision based on the Pass/Fail status of each region of interest in the Match Colors step.