Saturday, 14 September 2013

New IR camera is user-configurable


New near-infrared cameras are few and far between and there is an increasing choice of thermal imagers, even if they tend (with a notable exception) to be very expensive. However, cameras working in the gap between the two are much rarer beasts.

Episensors of Bolingbrook, Illinois have announced a new camera working in the short wave infrared (which lies just beyond photographic/near infrared) and which is intriguing, not just because they describe it as 'low cost' (not sure just how low) but also because of its versatility. Here's a paragraph from their press-release.
The infrared camera company Episensors, Inc. recently launched a new type of portable infrared camera called the Night SWEEP-1 (“NS-1”). Infrared cameras can see light that is invisible to the human eye and provide imaging at night and through obscurants like smoke and fog. What sets NS-1 apart is its portability and customizability, which allows scientists, researchers, and others to utilize the camera in the field, without sacrificing the capability of swapping between short-wave, mid-wave and long-wave infrared focal plane arrays, lenses and other components. Based on a patent-pending design, this infrared camera system is fully customizable. The camera can be configured with a pour fill Dewar or a closed cycle Integrated Dewar Cooler Assembly (IDCA) depending on the customer’s preference.
An excellent technical note on their web site explains the wavelength domain this camera covers. It's notable not just because the user can change the imaged band but that the extended SWIR (short-wave-ir) band, between 1 and 3 µm (1000 and 3000 nm) not only has some haze and smoke penetration ability but also contains a sweet spot where there is some smoke penetration but also the radiation goes through glass. Output resolution is 320 by 256 with plans for 640 by 512. The digital resolution is 14 bit and I assume having a supercooled sensor (that Dewar referred to in the note is a thermos flask of something like liquid nitrogen) will give a low noise floor.

So this camera is a kind of infrared SLR and operates between photographic infrared (which ends around 1500 nm) and the thermal bands and operates using reflected radiation (from the sun for example) while thermal imagers show radiation from the objects themselves. I believe this mid-infrared imaging is sometimes referred to as reflectography and has applications in art restoration amongst other things.

Check out the videos on the web site. They look like photographic infrared rather than thermal but you will notice some smoke penetration. It'll come down to particle size and by configuring the camera the user will be able to balance haze and smoke penetration against things like glass transparency. The nearest I've seen to this in other devices is where a single unit combines two different cameras.

Whether we will see the NS1 on this side of the Atlantic is currently debatable as some of the technology is export-restricted.

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