Polarization state imaging in long-wave infrared for object detection

摘要

The article discusses the use of modern imaging polarimetry from the visible range of the spectrum to the far infrared. The paper presents the analyzes the potential for imaging polarimetry in the far infrared for remote sensing applications. In article a description of measurement stand is presented for examination of polarization state in LWIR. The stand consists of: infrared detector array with electronic circuitry, polarizer plate and software enabling detection method. The article also describes first results of measurements in presented test bed. Based on these measurements it was possible to calculate some of the Stokes parameters of radiation from the scene. The analysis of the measurement results show that the measurement of polarization state can be used to detect certain types of objects. Measuring the degree of polarization may allow for the detection of objects on an infrared image, which are not detectable by other techniques, and in other spectral ranges. In order to at least partially characterize the polarization state of the scene it is required to measure radiation intensity in different configurations of the polarizing filter. Due to additional filtering elements in optical path of the camera, the NETD parameter of the camera with polarizer in proposed measurement stand was equal to about 240mK. In order to visualize the polarization characteristics of objects in the infrared image, a method of imaging measurement results imposing them on the thermal image. Imaging of measurement results of radiation polarization is made by adding color and saturation to black and white thermal image where brightness corresponds to the intensity of infrared radiation.