CCD的输出响应与相机MTF测试

Output response of CCD and MTF test of CCD camera

以往在测试CCD相机的调制传递函数 (MTF)时 ,通常未考虑CCD像元的输出响应对测试的影响 ,因而导致了相机的MTF测试数据与理论计算值存在着一定的偏差。在采用高对比度靶标对线阵CCD相机MTF进行测试时 ,根据对测试数据的分析 ,发现在CCD像元的响应中包含着一种不同于像元暗电流的基底响应。通过考察CCD在不同照度下的输出响应 ,将以往的CCD绝对定标公式进行扩展 ,可以得出CCD像元的基底响应与暗电流对计算相机MTF的影响关系。据此 ,可以在CCD相机系统测试过程中得到相机的真实MTF数据 。

When testing MTF of CCD camera, the response of pixels at low irradiance is usually neglected, which causes relative large deviation between test value and theoretical value of MTF High contrast target pattern is used to test MTF of CCD camera It is found that there exists a kind of zero input response other than dark current The relationship between the response characteristics of CCD at different irradiances, especially zero input response and dark current, and output modulation of camera is deduced Moreover, absolute calibration formula of CCD is expanded to better describe the response characteristics of CCD Therefore, it is possible to obtain relative accurate MTF values At the same time, it provides a good way to process the images of CCD camera