基于非特定图像的红外成像系统调制 传递函数自动测量方法

机载红外成像系统的性能评估对于战机任务执行效能具有重要意义。 调制传递函数(MTF)是衡量红外成像系统性能 的典型指标。 现阶段 MTF 的测量依赖于特定的图像特征与人工操作,难以实现实时与批量评估。 为此,提出了一种基于非特 定图像的 MTF 自动测量方法,以倾斜刃边法为基础,通过图像刃边检测、目标区域提取以及改进的刃边计算方法,从不含有特 定景物特征的实拍图像中自动获得 MTF 点值,并构造红外成像系统等效物理模型以实现 MTF 曲线的拟合,进一步滤除随机误 差。 最后,以某型号无人机红外成像系统作为验证对象,将实验室测得的 MTF 与基于非特定实拍图像计算的 MTF 进行对比, 两者的绝对误差在 0. 06 以内,证明了方法的可行性与有效性。 该自动测量方法能够较为准确且实时地得到系统的 MTF,为不 便进行地面实验的红外成像系统提供了一种新的性能测试思路。

Automatic measurement method for modulation transfer function in infrared imaging system based on non-specific images

The performance evaluation of the airborne infrared imaging system is very important for the task performance of aircraft. modulation transfer function (MTF) is a typical index to measure the performance of the infrared imaging system. At present, MTF measurement depends on specific image features and manual operation. Hence, it is difficult to achieve real-time and batch evaluation. In this article, an automatic MTF measurement method based on non-specific images is proposed. The method can automatically obtain MTF values from actual scene images without any specific features, which is realized through image edge detection, target region extraction, and the improved slanted edge method. Then, an equivalent physical model of the infrared imaging system is established to achieve MTF curve fitting and filter out random errors. Finally, a certain type of UAV infrared imaging system is taken as the verification object, and the absolute error between the MTF measured in the laboratory and the MTF calculated based on non-specific actual scene images is less than 0. 06, which proves the feasibility and effectiveness of the proposed method. This automatic measurement method not only can evaluate the MTF accurately in real time, but also provide a new performance testing idea for infrared imaging system which is inconvenient to conduct ground experiments.