An adaptive image enhancement algorithm and real time implementation for an infrared imaging system

摘要

Present day thermal imaging systems are designed based on highly sensitive infrared focal plane arrays (IRFPA), in which most of the preprocessing is done on the focal plane itself. In spite of many advances in the design of IRFPAs, it has inherent non-uniformities and instabilities, which limits its sensitivity, dynamic range and other advantages. Whenever there is little or no thermal variation in the scene, the thermal imager suffers from its inability to separate out the target of interest from its background. Thus, most of the infrared imagery suffers from poor contrast and high noise. This results in object not being visible clearly. The problem becomes complicated because of dynamic background and non-availability of background clutter characteristics. In this paper, we present a adaptive approach for image contrast enhancement that expands the range of the digital numbers in a self-adaptive manner. This algorithm has been tested on the field-recorded data and is observed that this technique offers excellent results for thermal imager operating in both 3-5 μm and 8-12 μm wavelength regions.