Mid-wave infrared polarization imaging system for detecting moving scene

In this Letter, a polarimetric analyzer is designed for a mid-wave infrared camera. This kind of infrared camera transforms into the mid-wave infrared polarization imaging system to measure the infrared polarization characteristics of the object in the moving scene. The polarimetric analyzer is designed by using the ultra-high-speed and high-position method to drive the polarizer to rotate uniformly at the speed of 900 rpm. The polarization state of the object scene is changed, and the mid-wave infrared camera synchronously acquires the infrared intensity image in different polarized directions, those of 0 degrees, 120 degrees, and 240 degrees. Then, a Stokes vector model is established with the basic rotation angles, and a sort-iteration method is proposed to process the original infrared intensity image. Three continuously neighboring infrared intensity images are used to calculate the degree of linear polarization (DoLP) and the angle of polarization (AoP), which make the infrared polarization image the same imaging frame as the infrared intensity image. Test results show that the mid-wave infrared polarization imaging system can complete the acquisition of the DoLP and the AoP images well with the frame frequency of 45 fps, which is suitable for the infrared polarization detection of the moving scenes. The study has great potential for polarization remote sensing and marine object detection. (C) 2020 Optical Society of America