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Hi-Tech Camera "Tastes" Apples to Ensure Quality

By Don Comis
August 7, 2002

Wouldn't it be nice to check an apple's taste before buying it, without chomping down? You surely wouldn't want an inspector pre-tasting the apple you buy, but how about a robot?

The robotic inspection cameras envisioned by Agricultural Research Service scientist Renfu Lu would "taste" every single apple by bouncing light off it to sense sugar content and firmness, the top two things that make an apple taste great.

Lu has developed mathematical equations that relate sugar content to the amount of light absorbed by an apple, and firmness to the amount of light bounced off the apple. Lu is an agricultural engineer at the ARS Sugarbeet and Bean Research Unit in East Lansing, Mich., the third largest U.S. apple-producing state.

Washington State produces almost half the nation's apples--and is partially funding Lu's work--while New York and Michigan together produce another 20 percent. Lu's research is critical to these and all apple-producing states.

Apple packinghouses currently rely on digital camera imagery to sort apples by surface appearance only, flagging those that are visibly defective or the wrong size or color. The current system can't detect bruises beneath the skin--or flavor and other internal qualities.

Lu looks deeper by adding lights and spectroscopy to analyze various wavelengths of reflected light. When the system is fully developed, specially designed software will allow a computer to sort apples by the internal quality attributes--firmness, ripeness and taste--required for various grades.

Lu's digital imagery system can easily be merged with those in packinghouses and adapted to other fruits such as peaches and pears. He is currently working with cherries as well as apples.

More information on robotic inspection for taste in apples can be found in the August 2002 issue of Agricultural Research magazine.

ARS is the U.S. Department of Agriculture's chief scientific research agency.