HD cameras enhance SORTEX E digital sorters

IT'S highly unlikely that foreign materials will be found in a bag of frozen fruit or vegetable, thanks to digital sorters that detect and remove unwanted bits of stones, glass or plastic. Fast, reliable and barely missing, the technology has improved efficiency at processing stage. In 2007, Bühler pioneered the use of such optical sorters with InGaAs cameras. This year, the company introduced InGaAs cameras with twice the capability of its existing ones – which means these cameras can spot much smaller foreign materials compared to their predecessors.

SORTEX E with the latest InGaAs cameras

The smaller they get

With double the resolution, the new InGaAsHD cameras can detect foreign materials 50 percent smaller than previously possible. They will be available in the SORTEX E product range and will enable processors of frozen fruits and vegetables to meet the highest safety requirements, while ensuring maximum quality of their product.

Frozen fruits and vegetables, such as strawberries, green peas, sweet corn or baby carrots, are a fast growing market segment in the food industry. Not only do they meet the demand for food that is quick and easy to prepare, in or out of season, but they can even be nutritionally superior to retailed fresh produce, as they are harvested at their peak ripeness – when most nutritious –  and frozen soon after, preserving their vitamins and antioxidants. “While increasing amounts of frozen fruits and vegetables are being processed, food safety regulations are tightening in most countries and processors have to guarantee the safety and quality of their products,” said Stephen Jacobs, Global Product Manager at Bühler.

Among the biggest safety concerns are foreign materials, such as small stones, pieces of wood and glass, or slivers of plastic. If contained within packaged frozen food products, they will pose health risks – including lacerations, choking or broken teeth. For food processors, they may result in expensive product recalls and damage to reputation.

Sensitive cameras

With its vast range of optical sorting solutions, Bühler has worked for decades to enable food processors to efficiently identify and remove foreign materials. This is achieved by using a variety of sophisticated detection technologies. InGaAs cameras, for instance, are very effective for separating foreign materials from good product of the same color. They are based on semiconductor sensors made from indium gallium arsenide alloy and operate in the short wave infra-red range (SWIR). As a result, they are able to detect even the subtlest of color differences that cannot be seen in the visible spectrum.

Bühler started the use of this technology for use in the packing line, as a final check, to ensure that difficult–to-detect packaging materials such as light colored wood in potatoes, cardboard in carrots and coloured plastic in vegetable mixes, were quickly identified and accurately removed from the product stream.

The company has continued to advance this technology and the development of the new high definition InGaAsHD cameras now mark the latest step in this process: “By combining a new hardware, software and lens package, we were able to engineer a new camera with double the resolution. As a result of this in-house development, our sorter will be able to identify foreign material objects down to half the previous size,”  Benedict Deefholts, Head of Sensor Development at Bühler, describes the key advantage of the new HD cameras.

Thanks to this development, Bühler’s sorting solutions for processors of frozen fruits and vegetables now offer even better detection and removal capabilities for a wide range of foreign materials in several different stages of the processing and packing line and is particularly beneficial for processors with stringent safety specifications such as for the baby food market.

The latest InGaAsHD cameras are now available for Bühler’s SORTEX E product line. Processors that are already operating SORTEX E optical sorters with Enhanced InGaAs cameras will be offered an upgrade option, enabling them to benefit from the improved detection performance of the new HD cameras with their current solution.