Infrared imaging of buried heat sources and material nonuniformities

Using a recently developed PtSi IR focal plane array imaging system, ZAE Bayern develops new IR measurement techniques for industrial and medical applications. In this paper we present three examples for the analysis of material nonuniformities and a buried heat source. A new method for detecting the surface moisture of porous solids has been developed. The water content at the surface is determined by using an infrared filter tuned to the water-specific spectral line at (lambda) equals 2.92 micrometer. With a numerical simulation of the water transport we determined the effective diffusion coefficient. Surface temperature transients are recorded after a short infrared irradiation excitation at a frame rate of 50 Hz to localize voids or blisters in solid materials. The method is tested for a glass substrate. The analysis is in quantitative agreement with the test configuration. Furthermore we show that it is possible to localize leaks in heat pipelines a few meters below the earth surface by dynamical infrared imaging techniques.