红外目标模拟系统DMD成像非均匀性分析及校正

Nonuniformity analysis and correction of DMD imaging in infrared target simulation system

基于数字微镜阵列(DMD)的红外目标模拟系统具有高分辨率、高帧率和大温度范围等优点,能够经济、有效地检测和评估红外探测系统的工作性能。为了研究基于DMD的红外目标模拟系统中照明系统的结构设计对成像均匀性的影响并减小像面照度不均匀性,提出了一种消除成像不均匀的方法,对DMD照明系统的结构参数进行了分析和设计,以成像光束截面积之比作为相对照度指标,建立了数学模型,用软件进行数值仿真,得到了能消除因渐晕导致的照度不均匀现象的结构参数和像面各点相对照度分布在88.75%~1;并用TracePro验证了理论分析的结果,得到像面各点相对照度分布在90.91%~1,与理论分析结果相符,证明了在DMD照明系统结构参数设计合理的情况下,该方法可以有效降低因渐晕导致的像面照度不均匀性,为红外目标模拟系统结构参数的设计和像面照度分析提供了参考。

The infrared target simulation system based on the digital micromirror device(DMD)has the advantages of high resolution,high frame rate and large temperature range,which can detect and evaluate the working performance of the infrared detection system economically and effectively.In order to study the influence of the structure design for illumination system on the imaging uniformity and reduce the illumination uniformity of the image surface in the infrared target simulation system based on the DMD,a method to eliminate the imaging nonuniformity was proposed.In which the structure parameters of the DMD illumination system were analyzed and designed,the ratio of the imaging beam cross-sectional area was taken as the relative illumination index,the mathematical model was established with the software for numerical simulation,and the structure parameters which could eliminate the illuminance nonuniformity caused by the vignetting was obtained.The relative illuminance distribution of each point on the image plane was ranged from 8.75%~1;the results of the theoretical analysis were verified by the TracePro,and the relative illuminance distribution of each point on the image plane was ranged from 90.91%~1,which was consistent with the theoretical analysis results.It was proved that in the case of the rational design of the structure parameters for DMD illumination system,the image plane illuminance nonuniformity caused by the vignetting could be reduced effectively,which provided a reference for the design of structural parameters for infrared target simulation system and image plane illuminance analysis.