Case Studies

Good Filter

Line Scan Vision Inspection of Molded Automotive Filter

Posted in Automotive, Machine Vision, Manufacturing Automation and Intelligence, Test & Measurement Automation


DMC designed a line scan vision inspection system for cylindrical molded filter components.  The system performs inspections of the complete circumference of each filter, rejecting defective parts.

Defect Part

Defect Part

Cognex DVT LS Camera

Cognex DVT LS Camera


The system's first inspection station rotates the part 360 degrees while the line scan camera, triggered by encoder feedback, takes images.  The line scan camera creates a composite image that consists of the complete circumference of the part.  Parts are rejected for molding defects such as blocked filtration holes, short shots (non-fills), flash, and improper dimensions.  Prior to implementation, DMC determined the optimum lighting and lens setup in DMC's vision lab, and verified the ability to detect the required defects.  An innovative lighting technique allows for a detailed inspection and short exposure times, lending to short cycle times.  The system has a second inspection station consisting of a standard 2-D camera inspection from the top of the part.

Although the inspection algorithm is sophisticated, DMC provided the customer with a user friendly system.  Tolerance parameters are stored in one central location, allowing for easy rejection criteria modifications.  Image marking is used to highlight out of tolerance areas on the display.  This provides the customer with a visual indication of the failure reason.

Customer Benefits

  • Improved quality through 100% automated inspection with detailed defect detection
  • Flexible tolerance parameters allows quick rejection criteria modifications
  • High production capacity with quick cycle time of inspection


  • Cognex DVT LS Line Scan Camera
  • Cognex DVT 545 SmartSensor Camera
  • Cognex DVT Intellect Vision Software