在红外热像仪的外场应用中,温度变化会对热像仪的光学系统特性产生影响,导致光学系统产生离焦,造成图像模糊,影响成像质量。针对这一问题,提出了机电式无热技术,利用移动透镜进行主动补偿,以消除或降低温度变化对图像质量造成的影响。基于实验数据研究了温度变化对热像仪焦距的影响,得到温度对焦距变化影响的规律。基于分析结果,得到不同温度下调焦电机补偿码值,并增加了温度测量接口,设计了自动补偿软逻辑控制软件。最后,在红外热像仪上进行了实物实验验证,验证实验结果表明,该方法可使长时间工作的红外热像仪图像一直保持基本状态。提出的机电式主动补偿方法避免了光学系统重新设计,具有较好的实践性和经济性。

In practical field application, temperature variance has obvious influence on optical systems of infrared thermal imager. This problem will cause un-focusing effect in optical system, and lead blurring problem in IR images. For this problem, a motorized athermalizing technology is indicated in this paper. Lens is moved to compensate the un-focusing effect caused by temperature variance. Based on the experimental analysis of temperature change on focal length, the law between temperature and focal length is obtained. From the analysis results, the motor compensation code under different temperature is derived. After that, a temperature measurement interface is designed, and the auto compensation logical control software is realized. Finally, this method is verified in practical IR imager. The verification test shows that, this method can keep the IR image in clear level during long term operation. This active compensation method shows good practicability and cost-efficient, while it avoids re-designing the optical system.