IR camera system with an advanced image processing technologies

Abstract

We have developed image processing technologies for resolving issues caused by the inherent UFPA (uncooled focal plane array) sensor characteristics to spread its applications. For example, large time constant of an uncooled IR (infra-red) sensor limits its application field, because motion blur is caused in monitoring the objective moving at high speed. The developed image processing technologies can eliminate the blur and retrieve almost the equivalent image observed in still motion. This image processing is based on the idea that output of the IR sensor is construed as the convolution of radiated IR energy from the objective and impulse response of the IR sensor. With knowledge of the impulse response and moving speed of the objective, the IR energy from the objective can be de-convolved from the observed images. We have successfully retrieved the image without blur using the IR sensor of 15 ms time constant under the conditions in which the objective is moving at the speed of about 10 pixels/60 Hz. The image processing for reducing FPN (fixed pattern noise) has also been developed. UFPA having the responsivity in the narrow wavelength region, e.g., around 8 μm is appropriate for measuring the surface of glass. However, it suffers from severe FPN due to lower sensitivity compared with 8–13 μm. The developed image processing exploits the images of the shutter itself, and can reduce FPN significantly.