METHODOLOGY OF DETECTION OF THERMAL REFLECTIONS IN THE INFRARED RANGE
Keywords:thermal imager, polarization, thermal prints, Stokes vector, polarization state, fingerprint detection
Background. Thermal reflections are a common source of problems in the interpretation of infrared (IR) thermal images. In particular, wet or polished surfaces, such as glass, metals, as well as brick and concrete, can easily reflect infrared radiation but are often overlooked. If left unchecked, these thermal reflections can lead to incorrect detection and recognition of the object or misinterpretation of its actual temperature.
Objective. The purpose of a theoretical analysis between the thermal radiation of an object and its reflection is to develop methods for the possibility of attenuation or at least identification of such prints using optical methods.
Methods. Light becomes polarized when it interacts with an object or matter through various mechanisms, such as scattering, reflection, or transmission. One of the possibilities of implementing such methods is the use of IR polarizers in combination with thermal imaging surveillance system.
Results. Article describes the physical and mathematical model of fingerprint detection and the possibilities of their elimination. The reflected light is partially polarized, so the main approach to its identification is to find the Stokes parameters. The authors considered three main methods for analyzing the state of polarization: the use of a rotating polarizer in front of the observation system, a special matrix with polarizers located on top of each pixel at certain angles, and a method based on dividing the amplitude in the polarimeter. full Stokes vector.
Conclusions. The advantages and disadvantages of the considered methods were revealed. The main features of structures and the cost of their implementation, which are necessary for each method, were determined, with the further purpose of their use in the development of a polarizing thermal imaging camera for unmanned aerial vehicles.
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