Superframing: scene dynamic range extension of infrared cameras

Infrared cameras are often used to capture high-speed digital video of scenes with enormous ranges in in-band brightness. A simple example of this would be a man standing next to a hot fire. Under normal operating conditions, it can be next to impossible to fully span a scene like this with the brightness dynamic range of an infrared camera. The brightest or hottest parts of the image will often be saturated, while at the same time the darkest or coldest parts of the scene may be buried in the noise floor of the camera and appear black in the image. Varying the exposure by changing the integration time is necessary to maximize the useful information recorded by the camera, but sometimes a single integration time is not enough to fully encompass a scene's variations. The technique of superframing consists of varying the integration time of the camera from frame to frame in a cyclic manner, then combining the resulting subframes into single superframes with greatly extended dynamic ranges. The technique and some sample data are described in this paper.