基于新型MRTD模型研究扫描型红外热像仪的视距

New MRTD model for range prediction of scanning thermal imager

基于人眼视觉系统可感知的阈值信噪比,提出预测红外热像仪最小可分辨温差(MRTD)方法。该方法根据频谱理论和红外热成像系统的二维调制传递函数,并结合匹配滤波器的概念,描述4条带标准靶的空间频谱函数。利用此空间频谱函数研究了4条带标准靶经过红外热成像系统的调制传递之后人眼视觉系统的感知信噪比。基于人眼视觉系统可感知的阈值信噪比,建立一个新的MRTD模型。依据此MRTD模型和视距模型,实现红外热像仪视距的预测。仿真结果表明,该方法预测的视距与实验数据有很好的一致性。

This paper presents a method for predicting the minimum resolvable temperature difference（MRTD） of thermal imager based on the perceived threshold signal-to-noise ratio of the human visual system.According to the frequency spectrum theory and two-dimensional modulation transfer function of infrared thermal imaging system,combined with the concept of matched filter,the method describes the spatial frequency spectral function of 4 standard bars.After the 4 standard bars are modulated and transferred by the infrared thermal imaging system,the perceived signal-to-noise ratio of the human visual system can be researched by using the spatial frequency spectral function.A new MRTD model based on the perceived threshold signal-to-noise ratio of the human visual system was established.The visual range prediction of thermal imager was achieved based on the MRTD model and visual range model.Simulation results show that the predicted visual range agrees with the experimental data.