Use a Blemish sensor to find flaws on a part (for example, scratches on a disc), or to make sure that a feature exists on a
part. Although verifying whether a feature is present on a part is more commonly an Area sensor application, a Blemish
sensor may be a better option when dealing with variable materials or uneven lighting.
Example applications include:
• Inspections that check for scratches on a part, and reject parts where the scratches are too numerous or larger than
acceptable
• Inspections that check for the presence of a label or marking on a part that may vary in color
To configure as a Blemish sensor, set the following parameters:
• ROI and Mask
• Sensitivity
• Edge Length Range
• Pass Count
Figure 43. Blemish Menu
ROI and Mask
Main Menu > Inspection > Sensors > [Sensor Type] > ROI and Mask
Note:
Sensor Type
in the menu path above refers to the sensor you are configuring or updating.
The Region of Interest (ROI) is the user-defined area on the screen that the sensor analyzes. The ROI type can be
rectangular, elliptical, or circular. From the drop-down list, select the ROI type to use for the inspection. Adjust the ROI as
appropriate for the inspection. An ROI can be as large as the entire Field of View (FOV).
Select the Enable Mask checkbox to allow mask ROIs to be used with the inspection ROI.
Sensitivity
Main Menu > Inspection > Sensors > Blemish > Sensitivity
Use Sensitivity to fine-tune how sensitive the sensor is to finding blemish or other edges within the ROI.
The sensitivity value helps account for light variations that might affect how well the sensor detects edges on inspected
parts. The sensitivity scale is from 0 to 100, where 0 means least sensitive and 100 means most sensitive. If set near 0, the
sensor only finds very sharp edges with strong contrast. If set near 100, the sensor finds very dim or blurry edges, and may
be unstable due to noise within the image.
Edge Length Range
Main Menu > Inspection > Sensors > Blemish > Edge Length Range
The sensor counts all the edge pixels it detects in the ROI. The bar at the bottom of the Edge Length Range screen shows
all the different contiguous edge segments found. Use the slider brackets to specify the edge length range in pixels. Edges
found within this range are considered to calculate the Pass Count. Edge segments within the two brackets [ ] are
highlighted in green and those outside the brackets are ignored and colored yellow. Move each bracket to add or remove
more of the edge segments from consideration. Zoom in to refine the range.
Pass Count (Pixels)
Main Menu > Inspection > Sensors > Blemish > Pass Count
The sensor aggregates all of the edge pixels that fall within the Edge Length Range and indicates the value with a small
colored bar at the bottom of the screen. If the result is within the range brackets, the bar is green, otherwise it is yellow.
iVu Plus TG and Color Gen2 Image Sensors
40
www.bannerengineering.com - Tel: + 1 888 373 6767