一种点目标探测系统能量集中度计算方法

A Method for Calculating the Energy Concentration Degree of Point Target Detection System

在点目标探测系统中,光学系统的能量集中度决定了单个像元收集到点目标能量的水平,直接影响点目标探测系统的图像信噪比。在相机设计完成后,需要对相机的能量集中度进行测试,评价相机的性能。传统方法对点目标探测系统的能量集中度计算采用"中心像元法",由于相机探测器中心位置偏移和靶标尺寸的影响,计算结果存在很大误差。文章通过建立点源靶标成像模型,分析出靶标尺寸和探测器位置对点目标像斑的影响,提出了求解点目标能量集中度的一般过程,并设计出了一种容易实现的计算方法。通过对点目标像斑进行高斯拟合,然后通过两次反卷积去除探测器位置和靶标尺寸的影响,实现了对能量集中度的求解。计算结果表明,文中提出的方法比传统方法更接近实际情况,具有工程应用价值。

In point target detection system, the energy collected by a single pixel is determined by the energy concentration degree of the optical system, which directly affect the detection signal to noise ratio. It is necessary to test the energy concentration degree after the completion of the camera design to evaluate the performance of the detection system. Traditionally, the energy concentration degree is calculated by dividing the sum of the point image energy by the center pixel energy. But the influence of the center pixel position offset and the size of the point target will lead to a big error. Through the establishment of a point source target imaging model, the influence of the center pixel position offset and the size of the point target is analyzed. The general process is offered for solving the point target energy concentration degree. And an easily achievable calculation method is designed. After the Gaussian fitting of the sampling result, the deconvolution is applied twice to eliminate the influence of the center pixel position offset and the size of the point target, and then the high precision solution of energy concentration degree is obtained. The calculation results show that this method is more close to actual situation than the traditional method, which has engineering application value.