Compensation of the Size-of-Source Effect of Infrared Cameras Using Image Processing Methods

While many infrared camera-specific properties are considered for practical application, the influence of the radiation distribution surrounding the measuring spot is often neglected for thermal cameras. However, this has a significant influence on the uncertainty of thermal imaging cameras when measuring absolute temperatures, referred to as the size-of-source effect. Since thermal cameras acquire information about the radiation distribution around a potential point of interest through their spatially resolved measurement, neighborhood pixels could be used to reduce the uncertainty. In this paper, a convolution filter is presented whose parameters are optimized with regard to the compensation of the size-of-source effect for two different infrared cameras. The results show that the filter can reduce the effect significantly for different object geometries or even at the border of a thermal image. The algorithm could be applied to infrared cameras as a post-processing step in the future.