Case Studies


Machine Vision System to Detect Defects

Posted in Machine Vision, Test & Measurement Automation


DMC developed a machine vision system to inspect chrome bars, identify defects, and group them into categories based on defect size.


Control-panel-in-a-factoryThe client wanted to improve their quality control, so they came to DMC to design a system that detects irregularities in their product: chrome bars. As a solution, DMC developed a system which used a line-scan camera to capture images of the chrome bars as they were rotated in front of the camera. This allows for the vision system to full inspect all sides of these 3D parts and identify all defects on all sides of the part. Due to the reflective nature of the parts to be inspected, careful consideration was taken to ensure that the selected camera and illumination would minimize impacts of glare which could appear as a false defect in the inspection.

In addition to performing the image inspection, the software is designed to communicate with PLC controlling the line, using digital inputs and outputs. The digital outputs are used to notify the PLC system when a defect was found. The software had to be able to handle multiple different lengths of chrome bars. Therefore, the system used digital inputs from the PLC to identify whether a bar was present for inspection or not. The software provided a user interface which provided the following key functionality:

  • Display of live images with defects highlighted 
  • Configuration of defect sizes for small, medium, and large defects
  • Recent defective images were buffered in memory
  • Functionality to support saving images to disk

Learn more about DMC's Test and Measurement Automation expertise and contact us with any project inquiries.

Customer Benefits

  • Easily detect defects and their severity
  • Configurable criteria for defect size
  • Reliable quality control


  • National Instruments LabVIEW
  • National Instruments PCI-6518 Digital I/O Device
  • National Instruments PCIe-1429 High-Performance Camera Link
  • Dalsa 1024-pixel monochrome line-scan camera - CameraLink
  • Chromasens CORONA II LED line scan illuminator