ELECTRONICS BY GLENN HAYES
Thermal Imaging Technology
W
e all know that operating a boat at night with limited visibility can be a stressful undertaking. If you’re lucky, you may have radar aboard to help alleviate some of the stress, but it isn’t always a perfect solution. Thermal imaging is a technology that was once only available to the military but is now being used by boaters to help with situational awareness when visibility might otherwise be an issue.
(Top) A typical image from a FLIR marine thermal imaging device. (Above) A FLIR ONE.
GLENN HAYES is a marine writer and photographer whose background in the marine industry and in marine electronics spans almost three decades and many thousands of miles at sea traveling the world. He can be reached at HAYESSTUDIOS.COM .
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A P R I L 2021
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What is it? Thermal imaging is not the same as night vision, although the two are often confused. Night vision pumps up or amplifies any ambient light that may exist and creates an image based on that amplified light. Thermal imaging works by detecting and displaying tiny differences in temperature (everything emits a heat signature) and creates a digital image based on those differences. The sensors in thermal imagers are thousands of times more sensitive than the sensor in your digital camera, although they operate in a similar manner. Infrared radiation detects subtle differences in heat through sensors that can distinguish wavelengths up to 14,000 nanometers, which translate into differences in temperature up to thousandths of a degree. These ultra-sensitive sensors create an image with differences in temperature represented with different shades of grey. This results in an impressive black and white image (that can then be colorized in different ways depending on the thermal imaging equipment) of a scene that is otherwise not visible to the naked eye. The technology can turn a dark and indiscernible scene into one that looks like a daytime black and white image of the same scene. FLIR (Forward Looking Infrared), the parent company of Raymarine, has developed this technology for all kinds of applications, such as law enforcement, military, industrial, and marine and maritime uses. Boaters can now take advantage of this technology with several models and versions of thermal imaging equipment. FLIR offers high-end thermal imagers that can be mounted aboard and controlled from the helm, with imagery displayed on multifunction displays. There are also handheld scopes and even a small and simple device called FLIR ONE, which attaches to your smartphone and turns it into a thermal imager.
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Benefits of thermal imaging There are advantages of using thermal imagers over traditional night vision. Because night vision works on amplifying existing ambient light, it can get blown out by bright lights, like city lights when entering an inlet, flashing lights, spotlights, etc. When this happens, the image is suppressed because the night vision can’t handle the very bright light and the image gets washed out. This is not the case with thermal imaging, which actually works just as well in daylight and bright haze. It can also be used when bright sunlight restricts visibility. Another advantage of thermal imaging over night vision is night vision requires some kind of ambient light to exist in order to operate; it can’t amplify light if there isn’t any. Thermal imaging detects subtle differences in temperature and as such can operate in zero light. It will work just as well on those dark, moonless nights on the water as it does any other time. Handheld thermal imagers can also be used to analyze onboard systems, looking through bulkheads and hoses to detect problems such as obstructions in cooling systems and electrical overloads. I have even used a handheld device to check the condition of the wheel bearings on my trailer during a long road trip while towing my boat. Thermal imaging can help boaters see better in low light or even super bright lighting conditions, such as solar glare. The technology can assist in situational awareness seeing markers, crab pots, small paddle craft and other navigation obstructions that may not show on radar. They are also incredibly effective at finding a person in a man overboard situation, with the heat from the individual’s head clearly showing on your thermal imaging display. Thermal imagers do have one weakness, however, because they detect subtle differences in heat signatures. Rain and fog can sometimes obscure the image by masking some of these temperature differences and reduce its range, clarity and effectiveness. Using it in conjunction with radar when these conditions occur is a prudent idea. FLIR does offer thermal imagers that combine the thermal image with low-light visual cameras, so you end up with images that take advantage of the strengths of both imaging devices. ★
TOP PHOTO COURTESY OF FLIR; PHOTO LEFT BY GLENN HAYES
Afraid of the dark? Don’t be.
