The fire industry is continuously tackling challenging situations where adverse conditions can affect rescue operations. Smoke from fire is a major disruption during a rescue operation and a camera that can see through smoke provides a fundamental advantage in solving some of the key challenges.
Cameras that operate in the visible spectral range cannot penetrate through smoke. This is due to the wavelength across 400-700nm (nanometres) being absorbed rather than reflected back. In contrast, short wave infrared wavelengths (SWIR) can penetrate through smoke therefore one can easily see through smoke particles in the air.
Infrared camera developer Emberion has created a camera based on nanostructured materials allowing it to capture an image from a visible range of 400nm to extended SWIR range up to 2000nm.
VIS-SWIR and SWIR lenses
Kowa’s HC-VIS-SW lens series is perfectly suited for Emberion’s wide spectral sensors. It has been specially designed to cover both the visible and SWIR spectrum. It shows minimal chromatic aberration and virtually no focus shift from visible up to 2000 nm. The lens range covers six focal lengths from 8mm to 50mm to meet any application requirements. For applications of long distance, Kowa offers a choice of long range zoom lenses optimized for the SWIR spectrum.
SWIR camera for challenging outdoor applications
A challenging area for outdoor imaging is bad weather conditions, for example when there is smoke, haze, or fog in the air. This can be addressed by SWIR imaging cameras. This technology can be utilised to see through smoke in outdoor conditions. During a test, the images captured by the Emberion VS20 camera with a Kowa VIS-SWIR lens clearly gives a clearer picture when taken through smoke than those shot with a standard CMOS camera, for example a smartphone image.
The camera can capture from 400-2000nm. The visible range (400nm-700nm) needs to be cut-off to only allow the SWIR wavelength to be detected to penetrate the smoke particles. Due to this factor, the image captured with the Emberion VS20 SWIR camera is achieved by utilising a 1000nm band pass filter in front of the KOWA lens. The addition of the filter actively cuts the visible light and is the key precondition to see through the smoke effectively. The comparison images clearly illustrate the difference in the scene using a CMOS camera and the Emberion VS20 camera which allows imaging through the heavy smoke generated from the campfire.
In a similar application, chemical or party smoke was generated to demonstrate the capability of such cameras. It was observed that the SWIR images clearly see through the chemical smoke which was impossible to see through with the naked eye.
SWIR technology offers advantages for fire safety
Seeing through smoke or harsh conditions provides added advantages in surveillance and fire safety applications as it can assist with early detection and assessment of the scene. It can help fire safety professionals in heavy smoke environments checking for trapped individuals or objects through glass windows or in a rescue operation using SWIR cameras. These cameras have a wide range of uses and the form factor can vary allowing fire safety professionals to use them as handheld units or smaller size cameras as detachable body gear units for flexibility in operation. For more information on Emberion visit: https://www.emberion.com/applications/
This is a collaborative publication by Emberion & KOWA.
Author: Dr Samiul Haque, Senior Product Manager, Emberion