Sep 27, 2007

Camera sorts by weight, color, shape and defects

At the new packing plant at Gilbert Orchards, a packing line recedes into the distance. Red Delicious apples are moving in individual cradles on eight parallel tracks. There are 38 packing stations along the line, where apples gently drop off for hand packing into cell trays and boxes.

A computer controls where the apples drop. As they enter the sorter at the start of the process, each apple is put on a pedestal and spun in front of a camera, where it is scanned and weighed. Each apple gets a PLU sticker – and the computer remembers where it is, what it looks like and signals it to drop when it reaches its appointed destination, perhaps minutes later and hundreds of feet away.

What started out looking like a pretty uniform lot of Red Delicious apples was broken into 43 combinations based on weight, color, shape and defects. In one of the fancier-shaped lots, long, slender apples – banana-like caricatures of Red Delicious – were going into boxes heading for China.

On size alone, apples can be divided into boxes of from 198- to 56-count, according to Sean Gilbert, who is systems manager and oversees packing in the fruit warehouse.

About 100 fruit people watched the operation in June, during a plant tour that hosted members of the International Fruit Tree Association. The Gilbert Orchards plant is in Wiley City, in the heart of its 1,800-acre fruit growing and packing operation in Washington’s western Yakima Valley.

Much of the company story is told on its Web site, www.gilbertfruit.com.

The Gilbert Fruit warehouse was rebuilt from the ground up in 2004 after a fire destroyed the original. The expanded, state-of-the-art warehouse and cold storage facility now packs and stores about 1.5 million boxes of fruit, both conventional and organic, year round.

The family business has been in operation more than 100 years.

Apple varieties include Braeburn, Gala, Pink Lady, Red Delicious, Honeycrisp, Golden Delicious, Granny Smith, Jonagold and Fuji. Peaches, nectarines and pluots are available from mid-July to the end of September. Pear varieties include Bosc, Anjou and Bartlett. In recent years, the orchards have expanded into sweet cherries and into vineyards, growing grapes and making wine under the Gilbert Cellars label.

The new packing facility contains two packing lines, the large one doing about 400 bins of apples a day. The smaller line handles about 150 bins a day of peaches and nectarines and all the organic products. Capacity is larger than current use.

Conventionally grown fruit is sold wholesale, domestically and internationally through Oneonta/Starr Ranch Growers.

“In addition, we have a strong partnership with some of the best organic marketers in Washington state,” according to the company. “This is a crucial element in the increasingly competitive organic market.”

Fruit also is sold retail locally.

A closer look

Twenty-five years ago, camera systems that could sort fruit and vegetables debuted in the industry.

There has been much technological progress since then – advances in camera technology, speed and digital image processing – and there are three major companies strutting their stuff in packinghouses around the world.

Members of the International Fruit Tree Association saw one of them in action during a tour of Gilbert Fruit Company’s new packinghouse in Wiley, Wash.

The system there was installed by engineers from Aweta-Autoline in Yakima, Wash., a subsidiary of the Netherlands-based company Aweta, which was one of the first to introduce camera sorting.

Engineer Rudy Freiberg designed the line at Gilbert and, in an interview, described the system, including Aweta’s Powervision Defect Sorting System, which comes into play after apples are initially cleaned, washed, waxed and dried.

Apples enter in bins, which are submerged in water to float out the apples. Bins continue on to a stacker while apples move to an elevator, where two workers remove trash and obviously bad apples.

The apples are brushed, cleaned, polished and waxed before they go toward another sorting area, where workers remove apples with major defects. Then they head toward the cameras.

The apples are oriented using V-belts, and each apple is positioned in a cup, where the camera takes a series of photos and constructs a three-dimensional image of it. During that process, a computer decides where the apple will be dropped.

Here’s the process as described by Aweta.

• As the apple moves and rotates under the camera, images are taken at four different angles.
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• From this stereo information, a three-dimensional view of the apple is computed.
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• Contrast filters compute the position of all scars and blemishes on the product. This is done with a combined image using visible and infrared light.
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• The stem and calyx are detected.
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• The color and diameter are determined.
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• The type of defect is identified, using more than a hundred stored properties.
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• With the requirements set by the user, apples are sorted into a specific quality class.
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The apple is evaluated on the Gilbert line for weight, color, defects and shape. The company also offers ProSort 3D, which uses beams of infrared light to determine internal defects, but that is not in place on the Gilbert line, Freiberg said.

“Each apple is directed toward a certain drop,” he said. “We know where every apple is along the line.”

The system moves fast. At Gilbert’s, eight lines of cups run side by side – and three cameras each evaluate 10 apples per second.

The system is programmed by the user, who can decide what size of dent or bitter pit mark constitutes a defect and just how red an apple has to be to join a certain group.

“Typical color systems are only capable of measuring average color and accumulated surface areas,” according to Aweta’s Web site. “Powervision can identify tiny scars from half a millimeter upwards, using more than a hundred parameters. Where a traditional quality sorting system classifies defects on the basis of a library of samples in the system, Powervision can be ‘trained’ by the user to evaluate deviations in these defects. By simply ‘showing’ examples to the system, Powervision can subdivide the product into different quality classes by the type of defects that are detected.”

On the Gilbert line, Frieberg said, there are 38 packing stations for apples in trays, plus four places where apples move into a bagging system and one additional area for cull apples.

The Aweta-Autoline name reflects a combination of the Aweta sizing and sorting technology with Autoline’s packing line design and installation.

While much of their work is in Washington, Freiberg said, the company’s territory covers Canada and the northern half of the United States. Installations are underway in New York, Minnesota, Ontario and Michigan, he said.