采用低温面源黑体实现红外系统宽动态范围定标

针对大口径地基红外辐射测量系统在辐射定标时存在定标时间长、成本高和设备机动性差等缺点,提出一种仅采用低温面源黑体实现红外系统宽动态范围定标的方法.首先对红外系统中的衰减片进行标校,测量其实际透过率并计算其辐射量;然后采用低温面源黑体在两个积分时间下分别进行辐射定标,根据定标结果解算系统响应率、杂散辐射和探测器自身偏置;结合标校获得的衰减片特性对低温定标结果进行外推,即可获得宽动态范围定标结果.为验证该定标方法有效性,分别采用该方法和通用的高温黑体加大口径平行光管定标法,对Φ600mm红外系统进行宽动态范围辐射定标实验.实验结果表明:本文方法的宽动态范围定标误差小于10.25%,能够满足该系统的辐射定标精度要求.该方法只需要一个低温黑体即可实现红外系统的外场宽动态范围辐射定标,操作简单、实时性强,具有一定的应用价值.

Radiometric Calibration Based on Low-temperature Area Blackbody for Infrared Systems with High Dynamic Range

To overcome the restrictions of long calibration time, high cost and poor maneuverability for radiometric calibration of the ground-based infrared radiometric measurement systems with large aperture, a radiometric calibration method, which is based on low-temperature area blackbody, for infrared systems with high dynamic range was proposed.First of all, the neutral-density filter in the system was measured to obtain its actual transmissivity and calculate its radiance.Secondly, the radiometric calibration was performed using low-temperature blackbody at two integration times.The response and stray radiation of the system as well as the bias of the detector were obtained on the basis of the calibration results.Then, the calibration results at high dynamic range could be acquired by extrapolating the low-temperature calibration results, combined with the measured characteristics of the neutral-density filter.To verify the effectiveness of the proposed method, a Φ600mm infrared system was calibrated at high dynamic range, using the proposed method and the typical method of high-temperature blackbody and large aperture collimator.The experimental results indicate that the error of the proposed method is less than 10.25%, which means the proposed method can be used to perform calibration for the system.The radiometric calibration for infrared systems with high dynamic range can be achieved only with a low-temperature blackbody in the outfield.The proposed method, with the advantages of simple operation and strong real-time, has a value for application.