大气光学特性对目标成像影响的分析

Analysis of the influence of the optical property of atmosphere on target imaging

大气吸收、散射和湍流效应导致地球大气中的图像恶化。大气光学特性具有复杂的空间和时间变化特性,不能简单地评价其对目标成像的影响。要透彻地了解红外成像系统在使用地区受大气影响的全貌,必须全面地分析各种可能的大气状态,使用概率进行评价。分析了导致图像恶化的大气因素和大气介质的调制传递函数。以大气消光系数和大气Fried参数为例说明了大气光学特性对红外目标成像影响的复杂性。介绍了图像恶化的修正方法以及应用这些方法时必须获取的大气光学参数和大气光学探测技术,为相关应用分析提供了示范。

The image obtained through the terrestrial atmosphere is degraded due to its absorption, scattering, and turbulence effects of light propagation. Optical properties of the atmosphere present complicated spatial and temporal characteristics, and their impacts on the imaging could not be judged simply. In order to have a thorough understanding about the influence of the atmosphere on the infrared imaging system on the spot, it is necessary to analyze imaging results under all possible atmospheric conditions and to describe the atmospheric effects in terms of probability. The modulation transfer functions of both turbid and turbulent atmospheric media, which result in image degradation, were analyzed in this paper. Two key parameters, i.e. the extinction coefficient and the Fried parameter, were presented as an example to illustrate the complicated behaviors of the influence of atmospheric optical properties on the infrared imaging of target. The atmospheric correction techniques for the degraded image, their required atmospheric parameters and related atmosphere optical monitoring devices were introduced. These techniques and devices could be applied in the corresponding imaging through atmosphere.