High-Speed Optics Enable Inline Strip Product Inspections

A new optical inspection system examines strip products like wire, pipe and rail much faster than any human ever could.

The Wire-AOI wire inspection system uses four cameras collectively to deliver 40,000 analyzed images of a moving workpiece per second. Courtesy of the Fraunhofer Institute for Physical Measurement Techniques.

The Wire-AOI wire inspection system, developed at the Fraunhofer Institute for Physical Measurement Techniques (IPM), uses a ring of cameras and processors to analyze the product during the manufacturing process. The system reviews workpieces moving up to 10 m/s, capturing 40,000 images every second and finding microscale defects in real time based on user-defined thresholds for depth, width and length.

The system consists of four cameras, each of which shoots 10,000 images per second and processes them in real time; the image processing system is based on cellular neuronal networks.

“Only a handful of models for industrial camera inspection are able to record this number of images in the first place, much less analyze them in real time,” said Dr. Daniel Carl, group manager for Inline Measurement Techniques at IPM.

The workpieces are illuminated by a specialized blinking LED. Because of the flash rate, the LED is eye safe despite its brightness.

When it detects a defect, the system triggers an alarm. Workers can then see the processed defects on a monitor and remove the corresponding pieces. The system marks the defect’s location and stores the associated camera image in a database. This way, the makers of strip products can identify, classify and document defects during production.

The researchers said the inspection system already has been used successfully by wire manufacturers.

For more information, visit: www.fraunhofer.de