# Infrared Imaging System with a Local Polarization Channel for Target Detection
## 1 Introduction  
Infrared imaging technology [1; 2; 3] perceives the difference in radiation energy between objects and their backgrounds; thus, it achieves target detection and identification. The demand for all types of infrared imaging devices [4; 5; 6] is continually growing in numerous fields, such as remote sensing [7], civil safety [8], and industrial production [9]. However, with the development of infrared stealth and camouflage techniques, conventional infrared imaging systems exhibit poor performance in detecting targets in complex environments because of their inability to sense small temperature differences. Infrared polarization imaging [10; 11] visually characterizes the polarized information of matter, which offers significant advantages for describing their physical parameters, such as shapes and surface roughness. In target detection applications, we need to accurately identify and locate targets in complex environments. Traditional infrared imaging systems may have limited performance when facing targets with infrared stealth and camouflage technologies. By developing an infrared imaging system with a local polarization channel, we can simultaneously obtain the infrared intensity information and polarization information of the target, thereby improving the accuracy and reliability of target detection. Therefore, as a supplementary tool to traditional intensity imaging, infrared polarization imaging [12; 13; 14] is capable of identifying objects and their backgrounds in complicated environments, particularly for discriminating artificial targets from natural backgrounds. However, similar to other imaging methods, polarization imaging has certain disadvantages [12; 15; 16]. For instance, the primary disadvantages of the division of aperture polarimeter [17; 18], which is a typical polarization imaging system, are the loss of spatial resolution, larger volume, and weight. Hence, it is necessary for imaging devices to combine the functions of infrared intensity and polarization imaging and employ either of them according to the circumstances. Notably, a locally magnifying imaging system, also called a foveated imager [19], has beencaching massive attention. These foveated imagers often work in visible wavelengths and are taken into account in many fields, such as medical instruments [20] and target detection and tracking [21].  
In this study, an infrared imaging system with a local polarization channel is proposed. The proposed system satisfies the infrared intensity imaging requirements of a wide field of view (FOV) and acquires magnified polarization images of objects in the field of interest (FOI) [22]. This system employs two infrared imaging channels: a peripheral channel for target searching and tracking and a dynamic local polarization channel for target recognition in the FOI. The two-channel images are on the same plane. An imaging simulation [23; 24] was performed using the system, and it demonstrated that the system could acquire local infrared and polarization information of the target while thoroughly monitoring the entire wide FOV. The results presented in this study have significant value for target detection, endoscopy, video surveillance, and agricultural monitoring.