Subsurface material recognition based on infrared time variation characteristics

Abstract

According to the problem of substrate recognition for coating materials, this paper proposes a technical approach to identify the under-coating materials based on the infrared time variation characteristics. Five specimens with the same coating and different kinds of substrates are designed; pulsed stimulation is applied on the surface of the specimens, and the infrared radiation variation is captured by an infrared camera. The thermal images sequences and temperature vs. time curve are processed, and the logarithmic temperature vs. time curve is analyzed; the deviation degree of the logarithmic curves from the -1/2 slope line (the theoretical logarithmic curve of single-layer material) is defined as the characteristic value of the logarithmic curves of different substrate materials. Therefore, different types of the substrate materials can be recognized. For practical application, a characteristic value database is needed, and this method can effectively identify subsurface materials with different thermodynamic parameters by comparing with the database.