This website uses cookies primarily for visitor analytics. Certain pages will ask you to fill in contact details to receive additional information. On these pages you have the option of having the site log your details for future visits. Indicating you want the site to remember your details will place a cookie on your device. To view our full cookie policy, please click here. You can also view it at any time by going to our Contact Us page.

Assuring food quality with infrared

03 August 2010

As the sophistication of IR cameras continues to increase, along with associated hardware and software, their use in automated systems is growing rapidly

Thanks to their combined imaging and temperature measurement capabilities they can be very cost effective for those involved in automated food production.

Thermographic cameras and their associated software can recognise the size, shape and relative location of target objects. Moreover, the electronics in the latest IR cameras provide fast signal processing that allows high video frame rates (60Hz or higher) to capture relatively fast-moving items on a production line.

Enabling technology The features of IR cameras that enable their use in vision applications are Gigabit Ethernet (GigE) connectivity, GigEVision compliance, a GenICam interface and a wide range of third party software that supports these cameras.

Other camera hardware features are also important. Generally, ultra-high detector resolutions are not needed in the targeted applications, so a typical focal plane array would be 320x240 pixels.

Nevertheless, outputting a 16-bit image stream of 76,800 pixels at a 60Hz frame rate amounts to about 74Mb/sec. While this is much slower than the capacity of a 1000-baseT Ethernet system, multiple cameras may be involved as well as a lot of other traffic on the network between image transmissions.

To speed up image transfers, data analysis and decision making must take place outside the camera. This is the reason there’s a good market for third party thermographic software. Another factor is most machine vision systems are custom-designed for specific production processes. And naturally, IR camera manufacturers supply various types of software to support their products and facilitate applications in these systems.

The food processing industry is one in which high level analytics are used with IR cameras for automated machine vision applications.

A broad field in which IR excels is the inspection of cooked food items coming out of a continuous conveyor oven. The primary concern is that the food has been thoroughly cooked which can be determined by the IR camera measuring the temperature. This is illustrated by a system inspecting hamburgers (pictured).

This can be done by defining measurement spots or areas corresponding to the locations of the burgers as they exit the oven. If the temperature of the burger is too low, the machine vision programme logic not only provides an alarm, but also displays an image to the oven operator to show the specific burger that should be removed from the line.

As in other applications, minimum, maximum and average temperatures can be collected for specific burgers or the field of view as a whole. This data can then be used for trending and summary of product characteristics (SPC) purposes.

In another example involving chicken fillets (pic 2), temperature is again used to check for thorough cooking. The pieces come out of the oven and drop onto another conveyor in more or less random locations. The operator can use the thermographic image to locate undercooked items and then remove them from the conveyor.

In the production of frozen entrées, IR machine vision can use pattern recognition software to check the efficient filling of food tray compartments. Similarly, it can be used for 100% inspection of the heat-sealed cellophane cover over the finished dish. An added function could be laser marking of a bad item so that it can be removed at the inspection station.

In summary, IR machine vision and temperature measurements can be applied to an infinite number of automated processes. IR images such as the FLIR A320 provide a stream of digitised IR images at fast frame rates for relatively high-speed processes, which can be transmitted over GigE networks to remote locations.

Compliance with GigE Vision and GenICam standards means that such cameras can be integrated with a wide variety of similarly compliant equipment and supported by a broad range of third party software.

Trigger and synchronisation capabilities allow them to control, or be controlled by, a host of other types of equipment. The availability of wireless and fibre optic line adaptors allow these cameras to be used almost anywhere, including over long distances.

Contact Details and Archive...

Print this page | E-mail this page


Article image A smart approach to vision inspection and code reading

STEMMER IMAGING, Europe’s largest independent supplier of vision technology and services to OEMs, system Integrators and reseller markets, will be showing a comprehensive range of vision systems at the PPMA Show.Full Story...

Article image Infrared vision system detects missing lids

While thermal imaging was once the preserve of high-end applications with large budgets, today’s technology is eminently affordableFull Story...

New top-port bench-top spectrophotometer

The Key to the chips


Article image A smart approach to vision inspection and code reading

STEMMER IMAGING, Europe’s largest independent supplier of vision technology and services to OEMs, system Integrators and reseller markets, will be showing a comprehensive range of vision systems at the PPMA Show.Full Story...


Article image Spray and save on the glazing process

Food glazes are widely used in the bakery sector to improve the look and taste of baked products. Traditionally, this coating process has resulted in substantial waste. Technology advances mean that this is no longer the case. Full Story...

Article image Your flexible friend in the food factory

Suzanne Gill finds out where thermal imaging technology can help around the factory. Full Story...

A dry-ageing process improvement

Self diagnostics: an enabler for predictive maintenance

What role does refrigeration play in the supply chain?