Forest Fires

Forest fires are a common problem in the western part of the United States for fire fighters. Such fires generate a large volume of aerosols, typically appearing as light, opaque smoke that obscures vision to large areas of terrain. Because fire fighters must work in this environment, any means to improve visibility for air and ground crews could have significant value.

This video shows the scene from the air, switching between the obscured visible camera and the SWIR image. Note how the SWIR image reveals the actual fire location.

It turns out that the fine airborne particles seen in most forest fires often completely block light in the visible part of the spectrum, but allow SWIR light to pass through almost unaffected. The scenes above were taken in visible and SWIR wavelengths from an aircraft flying above a recent fire on Mount Hood in Oregon. The visible image shows large, billowing clouds of smoke; whereas, in the SWIR image, much of the smoke is transparent, allowing the capability to see flames and individual trees. Using SWIR, the actual progress of the fire, jumping from tree to tree, may be imaged and tracked. The video, is particularly dramatic in showing the benefits that Sensors Unlimited SWIR cameras offer; especially in terms of new capabilities for fire fighters. We stress that the ability of SWIR light to penetrate aerosols is seen in many, but not all situations. At some level of aerosol density, even SWIR wavelengths will not pass; however, as we have seen in fog SWIR continues to provide a substantial advantage when compared against visible, Silicon-based, imagers.

SWIR cameras can also see well in many otherwise dark conditions thanks to atmospheric "night glow", a night radiance that takes place with the recombination of hydrogen and oxygen in the upper atmosphere at night. Improved nighttime identification and contrast are possible with the addition of covert illumination.

The Mount Hood forest fire images were taken from a Cloud Cap TASE Duo gimbal that features a Sony visible camera and Sensors Unlimited SWIR camera.

Cloud Cap's TASE Duo stabilized gimbal was mounted on a manned Cessna 172 flown at ranges between 2km and 7km from the fire hot-spots.

For more information on Cloud Cap Technology products and the gimbal used here please visit www.cloudcaptech.com/default.shtm.

The Western wildfires burned more than 7 million acres in 2015

The U.S. Forest Service requested assistance from UTC Aerospace Systems, to provide them with additional Sensors Unlimited (SUI) SWIR Handheld Systems for the Aerial Observers who were tracking 15 active fires in Idaho and California.