Sensor and camera helps feed the chickens

Researchers at Raytek (Santa Cruz, CA) have come up with an innovative idea for remote infrared (IR) temperature measurements by integrating an IR thermometer with a visual-spectrum charge-coupled-device (CCD) camera.

Dec 1st, 2002
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Researchers at Raytek (Santa Cruz, CA) have come up with an innovative idea for remote infrared (IR) temperature measurements by integrating an IR thermometer with a visual-spectrum charge-coupled-device (CCD) camera. The device, which hit the market last fall, has managed to find applications in areas as diverse as airline kitchens, chicken coops, and oil platforms (see figure).

At the low end of the price-performance scale, simple IR thermometers cost between $650 and $1000, while IR imagers at the high end are generally one to two orders of magnitude more expensive, according to Raytek product manager Ken Pomper. So the company decided to combine the two into one device that lists for about twice the price of an IR thermometer by mounting a VGA or quarter-VGA visual-spectrum CCD camera on an IR thermometer with a coaxial laser-sighting system.


Combination infrared thermometry and CCD photography device projects bullseye onto measurement object.
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The laser-sighting system places a small bullseye on the spot where the temperature is actually scanned; the system also places a date and time stamp on the photograph to indicate when the measurement was taken. When connected to a personal computer, the system can monitor processes in real time and capture diagnostic images when high- or low-temperature thresholds are exceeded. The smallest temperature measurement spot size is about 0.75 in. at a distance of about 18 in. and increases at a ratio of about 60 to 1 with distance from the measurement object. A close-focus version of the device provides an even smaller spot size of 0.25 in.

"A catering company in Japan bought a few to document that they were delivering food to an airplane at the right temperature," Pomper said. "They needed a close-focus version to document that different foods in various parts of the food tray were all at the right temperature. So they just take photographs, store them, and are all set for governmental compliance."

An independent contractor who monitors automated feeding-track systems at chicken hatcheries in Oxfordshire, England uses the device to scan for and document abnormal rises in temperature in the various motors, switch gears, drives, and ventilation systems that ensure healthy chicken nutrition.

A 635-nm-emitting laser diode projects the bullseye onto the measurement object; the laser appears about twice as bright to the human eye as a 650-nm-emitting laser. "If they are using it in the daylight, they have a much better chance of seeing it," he said. A prism-ring optical system splits and rotates the beam in the coaxial laser-sighting system to provide a longitudinal profile in conformance with the profile geometry of IR emissions.

Actually integrating the two systems provided several technical challenges, Pomper said. "The camera has its own memory and the thermometer has its own memory, so we had to coordinate the storage and the association of the photos with the data. We also have to know when the photographic memory is consumed," he said. "Also, because they are sharing the same power source, we had to make sure the battery life was adequate, and alignment between the photography and the IR thermometry was critical."

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