Glossary Definition

MWIR (Mid-Wave Infrared) Cooled Thermal Imaging Surveillance Cameras Longer Range than LWIR Uncooled

Cooled thermal refers to a thermal camera that utilizes an integrated cryogenic cooler. Since thermal cameras work by detecting radiated heat, any extra heat in the camera increases unwanted background noise in the image. The cryocooler chills the thermal image core to temperatures as low as -196°C (-321°F), which increases the sensitivity and accuracy of the thermal image, dramatically increasing both range and performance.

A Medium-wave infrared (MWIR) surveillance camera is IR camera that is sensitive to thermal energy (Heat) between 3 to 5 micrometer  (3-5μm 3,000-5000nm.  Most MWIR camera are cooled thermal which means they have an integrated cryogenic cooler that dramatically increases the sensitivity of the camera by cooling them down to as low as 77° Kelvin (-196°C or -321°F).  Cooled Thermal cameras see longer range than uncooled cameras as their greater sensitivity allows for bigger less efficient (higher F-stop) lens than LWIR uncooled cameras. Infiniti's 85~1400mm cooled thermal cameras provide up to 55km for vehicle detection based on DRI military standards making them the best choice for long range night vision.  One drawback is MWIR cooled thermal cameras are higher cost than standard uncooled LWIR cameras.   Infiniti offers both MWIR Cooled and LWIR Uncooled infrared modules in 640x512 1024x720 1280x1024, 1920x1080up to 5MP. We sell as open frame modules (lens and sensor attached) or as complete integrated PTZ cameras with Visible and SWIR sensors for ultra long-range imaging and threat detection even in complete darkness. 

Most cooled thermal cameras are InSb and need to be cooled to 77° Kelvin (-196°C or -321°F). These coolers need to run continuously, requiring replacement roughly every 8,000 to 10,000 hours of operation. Infiniti has options that run at a higher temperature, such as our X-Hot sensor which comes in 15μm, 10μm and 5μm pixel pitch (size of the pixels) . Since our X-Hot sensor doesn’t need to be cooled as low, the coolers have longer lifetimes which reduce the cost of ownership. Of course, all cooled thermal cameras will require maintenance at some point; even if the cooler itself does not fail, sometimes the seal and dewar assembly can, which is why cooled thermal cameras have higher maintenance costs compared to uncooled thermal or visible cameras.

Since cooled thermal IR cameras are so sensitive to tiny temperature differences, they can spot a target with only a few degrees temperature difference from its background. They work on mid-wave infrared wavelengths (MWIR) and typically use wavelengths of 3-5µm (3000nm to 5000nm). The combination of the cooled image core and the ability to work on the MWIR spectrum, when used with Infiniti’s long-range optics, means ultra-long range detection capabilities (up to 20 miles or 30km) even if there are only a few degrees temperature variance between the target and background. While cooled cameras are a significant investment and are considerably more expensive then uncooled, their superior range and performance allows them to deliver results that uncooled thermal cameras simply can’t achieve, making them a vital solution for certain applications such as coastal surveillance, and a cost-effective solution in applications such as border security, where the longer range of cooled thermal can cover the same perimeter length of up to 5-8 individual uncooled thermal cameras. 

Infiniti optics custom builds all types of EO/IR solutions and can offer them as open frame modules (lens and sensor attached) or as complete integrated PTZ cameras with Visible and SWIR sensors for ultra long-range imaging and threat detection even in complete darkness. 

For more information about thermal infrared imaging for night vision and surveillance see our Thermal Imaging Explained page.

 

Full Glossary