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Computer Vision to Detect Foreign Objects

Published by the American Society of Agricultural and Biological Engineers, St. Joseph, Michigan

Citation:  Paper number  056015,  2005 ASAE Annual Meeting . (doi: 10.13031/2013.19544) @2005
Authors:   John Stewart
Keywords:   Machine vision, foreign material, food safety

The detection of foreign objects and contaminants in food is a critical safety task. With the level of automation at every level of food production and the rates at which food is being produced, it is becoming increasingly more important to have systems that can automatically detect foreign matter along the way.

Plastic is common in the food processing industry and is used in liners, containers, disposable gloves, food testing instruments, hearing protection, identity badges, conveyor parts, and guides along conveyors. Plastic conveyor parts are a particular risk because they are hard and small pieces can be created if a conveyor becomes jammed or if parts are improperly inspected. Regular inspection of conveyor and accounting for production parts is common practice, but pieces worn plastic parts may not be discovered until after the product has left a facility.

This paper describes a color vision system designed to find non-metallic, foreign objects larger than 1.5mm in a processed meat stream. Many processing operations have already standardized on blue color for non-metallic objects that are present in production areas to make those objects easier for human inspectors to see. The same blue color scheme could make an computer vision system very practical for foreign object detection and removal. The system to screen for blue plastic parts can be integrated into the kick-off devices used with preinstalled metal detectors, so the system could be inexpensive to implement.

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