Research For Micro-Polarizer Array Long-Wave Infrared Imaging System's Calibration Method

Infrared polarization imaging detection can be an effective complement to conventional infrared imaging detection,with advantages in highlighting camouflage targets.Micro-polarizer array long-wave infrared imaging systems have gradually become a research hotspot in recent years,under the Micro-polarizer array manufacture error and focal plane array response error,the system's precision is low before calibrate,following the appear of indigenous systems,the research on calibration methods has practical significance.For the purpose of improving precision and image quality,a polarization calibration method by stepwise calculating parameters such as polarization direction and extinction ratio is designed,and an imaging correction method combining blind pixels and non-uniform correction is proposed.Finally,the quantitative and the real scene experiments show that this method is beneficial to improve the system's accuracy.The key aspects are summarized as follows:(1)Comprehensively analyze the imaging process of Micro-polarizer array longwave infrared imaging system,mathematically analyze polarization information calculation principle,under the analysis of Micro-polarizer array manufacture error and focal plane array response error,introduce the shortcomings of the existing calibration methods,and the process with polarization calibration and imaging correction is designed.(2)A polarization calibration model of multi-polarization parameter stepwise calculation for this system is designed,by determining the relationship between the pixel level response values and the incident light power,introduce the generalized optical transmittance,design the experimental method to calculate the polarization direction and extinction ratio step by step,independent of large-scale equations to obtaining the Muller matrix at each position,using the calculate method of polarimetric information under normal conditions,the Stokes vector of the incident light is quickly calculated;(3)An imaging correction method combining blind pixels and non-uniform correction is proposed,double directional derivative operation detect blind pixels in Stokes vector image,introducing the nearest neighbor super pixel and reference super pixel,discuss classification method of blind pixels and point targets,and a high-precision calibrate method is realized according to the polarization parameter distribution in the blind pixel's neighborhood.And a non-uniform correction method is proposed,which using parameters such as amplitude and offset,realize the approximation of each position response value to the optimal response value,fit the relationship between amplitude,offset and incident light power,so the adaptive process is described.(4)Through the quantitative and the real scene experiment's result,tested the polarization calibration model and the imaging correction method's practicability,reflect the effectiveness of the methods as mesh before and after calibration,use the mean square error as an indicator to quantify the polarization calibration accuracy.The results show that this methods has positive significance for improving the system's practicality...