Babbage | Infrared imaging

Hot or not?

Thermal cameras could be coming to a mobile phone near you

By D.H.

THERE is a long list of technical innovations that start out as the preserve of the military or academia but end up ubiquitous. The last stage of the spread seems to be integration into mobile phones—as has happened with digital photography and GPS-enabled location services.

This month will see the first encroachment onto the mobile phone of another technology that was once far out of the average consumer’s reach: thermal imaging. This is not the green-tinted imagery of “night-vision” gadgets, which amplify a tiny amount of reflected light. Thermal cameras instead capture the infrared light coming directly from objects, each temperature corresponding to a different false colour that together make up an image. A thermal camera, in effect, is a thermometer that can take pictures.

Such kit—developed by the US military and first deployed during the Korean War—has already found diverse uses. Firefighters employ thermal cameras to see through smoke, and search-and-rescue teams use them to search and rescue. The high-end models of Mercedes and Audi offer thermal cameras to spot pedestrians in dark or foggy conditions. Even birds benefit; in the Cambridgeshire Fens, the Royal Society for the Protection of Birds uses them to monitor corncrakes hiding in reed beds.

More quotidian applications make use of subtle temperature differences, such as those created near leaky windows and doors, or along a length of pipe in which there is a blockage or a damp patch. All animals have a heat signature, so pest controllers can use thermal imagers to spot mice, rats and even wasps’ nests inside cavity walls.

But affordable, handheld versions available to DIY-minded consumers have been painfully primitive by comparison to their industrial cousins. That now looks set to change as a number of efforts aim to put the technology in far more hands, by linking it to mobile phones.

In late 2012, Andy Rawson decided to build his own crude thermal imager, which he attached to his phone, overlaying a thermal image with that from his phone’s own camera. Internet fans of such "hacking and modding" predictably went wild; the ensuing crowdfunding effort to raise $20,000 instead brought in $196,000 and the resulting IR-Blue product sold out on both sides of the Atlantic. The next version of the technology, dubbed the Hema-imager, is the subject of another crowdfunding campaign. Mu Optics was founded in early 2013 and found similar crowdfunding success. It is taking pre-orders for a higher-resolution device than the Hema-imager. Established players in the market will also have their say. This month, Apple will begin selling the FLIR ONE, a slickly iPhone-integrated thermal imager from FLIR, the biggest firm in the infrared-imaging market, along with a suite of apps to make use of it.

But are these merely expensive toys destined to be used a few times, or could they spread as digital photography has? In the first instance, average consumers will benefit from using the devices in the way that professionals already do. Spotting heat loss, insulation gaps and damp patches that are invisible to the eye might help the domestic thermal imager pay for itself.

Plants also have a slightly different temperature to the background, and this can be an indicator of health. Farmers already use thermal scans to detect signs of moisture stress, providing advance indication that trees or crops need watering; gardens might be next.

On the medical side, thermal imaging can detect fevers from a distance. Airlines used it during the SARS outbreak to identify passengers who might be at risk. A mass-market version could help schools and nurseries with the everyday problem of spotting feverish children carrying infections. Closer up, inflammation often marks the site of tissue damage, and thermal imaging is used in both sports medicine and equine medicine to help identify leg injuries.

FLIR Systems chief executive Andy Teich says that over 2,000 developers signed up to write apps for the FLIR ONE, covering the full range of traditional infrared imaging applications. There were also a few “left-field” ideas that nobody had thought of previously—ideas about which he is guarded. Expect to see more thermal images and, indeed, thermal imagers as they crop up online. In time, they may even find their place inside phones, rather than tacked onto them.

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