制冷型热红外焦平面成像系统数据处理的关键技术

Key Techniques of Data Processing for Cooled Thermal Infrared Focal Plane Array Imaging System

长波红外（8～12.5 μm）焦平面的性能在很多方面弱于中短波红外器件,其非均匀性及盲元状况较严重.本课题首次在国内引进了法国Sofradir公司的320×256像元HgCdTe长波红外焦平面探测器MARS VLW RM4,其波长响应范围为7.7～12 μm.基于一套高帧频低噪声信息获取系统,经过动态范围标定,实现了一套动态范围为250～330K、噪声等效温差（Noise Equivalent Temperature Difference,NETD）小于50 nK的热红外成像系统.针对焦平面各像元的响应特性,研究了适用于热红外成像系统的非均匀性及盲元校正方法,提出了基于辐射定标的非均匀性校正和盲元检测.经实验验证,其校正效果优于两点定标法,且易于工程实现,基于辐射定标的结果可实现精确的温度反演.

A long wave infrared （8-12.5 μm） focal plane array can not operate better than medium and short wave ones in many respects. Its non-uniformity and blind-pixel problems are quite serious. A MARS VLW RM4 320-256 HgCdTe long wave infrared focal plane array detector with a wavelength response range from 7.7 μm to 12 μm is imported from Sofradir Company in France. On the basis of a high frame frequency and low-noise information acquisition system of which the dynamic range is calibrated, a thermal infrared imaging system is developed. Its dynamic range is from 250 K to 330 K and Noise Equivalent Temperature Difference （NETD） is less than 50 mK. According to the response characteristics of the pixels in the array detector, the non-uniformity and blind-pixel correction method suitable for thermal infrared imaging systems are studied. A non-uniformity and blind-pixel detection method based on radiation calibration is put forward. The experimental result shows that the method is better than the two-point method. It is easy to be implemented in engineering. The result based on radiation calibration is useful for more precise temperature inversion.