A computer-vision system that automatically detects and removes plastic and other colored foreign objects in finished food products is in its final development stages. The system, which sits above the production line adjacent to metal detectors, is first trained to identify the conveyor belt background and desired characteristics for the food product. This information then is stored in the computer's hard drive.

As the product moves along the conveyor, the computer-vision system captures digital pictures and analyzes them. If the system sees an object it does not recognize, it records the digital image and activates an alarm and kick-off device that removes the product from the line.

Although this system can determine a full range of color, lab tests have focused on finding blue and green objects. Blue has become a standardized color for plastic used in the food-processing environment.

“Few foods are blue, so food processors hope that line workers will recognize any foreign objects making their way into the product stream,” said John Stewart a research engineer of the Georgia Tech Research Institute who is leading the computer-vision system development team.

Although people are easily trained, they are also easily distracted, said GTRI research engineer Doug Britton, who is also working on the project.

“The product stream is moving very quickly -- about 12 feet per second, which is the equivalent of eight miles per hour. If a person blinks or looks away for even a second, they can miss a problem,” Britton explained. “In contrast, machine vision is very diligent. It doesn't get tired or bored.”

GTRI's Traditional Industries Program for Food Processing funds the project with additional support from industrial partners.