Case Study

Using Lasers to Identify Substandard Food

Published: April 28, 2009

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Alerting technicians in a food processing plant about a substandard item on the processing line could be much easier in the future with a laser projection system developed by GTRI researchers.

"We've developed a system that shines a laser light symbol onto the imperfect food product so that it can be removed from the conveyor belt, allowing the technicians to maintain their focus on the product stream without the need to look up at a monitor," said GTRI research scientist Simeon Harbert.

With funding from GTRI's Agricultural Technology Research Program, Harbert designed and fabricated the system, which consists of equipment installed in two plant-ready waterproof enclosures. One contains a laser, high-speed laser-pointing mirrors and a small camera, while the other houses the controller and power systems, and software to control the system.

The camera is used to track the substandard product while galvanometers move the mirrors that reflect the laser beam and essentially create line drawings of geometric shapes - such as circles, squares, triangles and stars - on top of the food product. Different symbols are used for the various types of defects.

"The inspectors will know immediately what's wrong with the food item based on the symbol and they can make adjustments to the forming, cooking or conveyor equipment as needed," explained Harbert.

The laser projection hardware is driven by software with several modules:

  • A product list module that keeps information about multiple product items in the laser projection area,
  • A tracking module that uses the built-in camera to track locations of product in the viewing area,
  • A laser projection control module that translates the product list information into laser projection symbols on the product, and
  • A computer server that receives product defect information relayed by an inspection system.

Harbert recently integrated the laser projection system with an inspection system designed by GTRI research scientist Colin Usher. The researchers are currently inspecting sausage patties for defects and relaying that information to the laser projection system. They plan to test the combined system in a food processing plant soon and envision that the laser projection system could be used for other applications.

"Because the system is modular and self-contained, it can be used whenever information that is not readily apparent to a worker viewing the product needs to be relayed," said Harbert.