多角度偏振成像仪相对光谱响应定标方法

Calibration Methods of Relative Spectral Response of Directional Polarization Camera

相对光谱响应是检测和评估多角度偏振成像仪性能的基本参数之一。采用基于激光泵浦氙灯光源的单色仪、消偏器、参考探测器和45°分束镜,搭建了一套多角度偏振成像仪相对光谱响应测量装置。采用分束镜同步测量的方法,降低光源的非稳定性影响;针对测试过程繁琐和测试时间长的问题,在基于现有不同开发平台开发的单色仪和数据采集系统的基础上,采用ActiveX控件与动态链接库技术,研制了一套相对光谱响应自动测试系统,降低时间非稳定性影响,提高测量精度和效率。采用多角度偏振成像仪490 nm和865 nm偏振通道作为应用案例,开展了相对光谱响应的整机测试实验。实验结果表明多角度偏振成像仪中心波长测量极差值与带宽均值的比值精度在0.11%以内,满足响应非一致性优于0.6%的定标要求。

The relative spectral respone is one of the basic parameters for detection and evaluation of the performance of the directional polarization camera. A set of devices to measure relative spectral response of the directional polarization camera was assembled, which consisted of laser pumping xenon light source monochromator, depolarizer, reference detector and 45° beam splitter. The synchronization measurement method of beam splitter was utilized to reduce the instability of the light source. On the basis of monochromator and data acquisition system developed by different development platforms, an automatic testing system for the relative spectral response was developed by using ActiveX and dynamic link library technology to solve problems of complex testing process and long testing time. This automatic testing system has reduced the impact of time stability, and improved accuracy and efficiency of the measurement.Taking 490 nm and 865 nm channel of the directional polarimetic camera as an example of application, the experiment of relative spectral response in instrumental level measurements was carried out. The experimental results showed that the accuracy of the ratio between measured range value of the center wavelength and the average value of the bandwidth of directional polarimetic camera is within 0.11%, which meets the responsivity non-uniformity calibration requirement of less than 0.6%.