变焦光学系统的景/焦深延拓及其分析

Application and analysis of the extension of depth of field and focus in zoom system

变焦光学系统在连续变焦过程中,由于变焦曲线的计算和加工精度,导致实际像面离焦,成像质量下降。变焦系统的特点是长焦距对应窄视场,短焦距对应宽视场。将波前编码技术应用于变焦系统,在系统的光瞳面设置相位掩模,则扩展了原系统的焦深和景深,使调制传递函数对离焦不敏感,同时提高短焦距宽视场的边缘成像质量。文章对原系统和应用波前编码技术的新系统的成像特性进行了分析和对比,随后讨论了掩模板的相位因子对系统的景深、焦深延拓以及对像质的稳定作用。仿真显示:变焦波前编码光学系统对离焦不敏感,可以很好地扩大系统的焦深和景深、稳定边缘视场的像质,具有很高的实用价值。

Because the calculating and processing accuracy of zoom curve lead to imaging defocused, the image quality of the zoom system declined. The features of zoom system are that long focal length corresponds to narrow field of view and short focal length corresponds to wide field of view. The masked aperture surface can extend the depth of focus and field of view of system, while it improves the imaging quality of the fringe field of view. The technology makes the modu lated of function (MTF) insensitive to the defocus. The imaging characteristics of original system and the wavefront cod- ingsystemareanalyzed.Thesimulationresultspresentthatthesysteminsensitivetothedefocushasalargerangofdepth of focus and depth of field while stabilizing the fringe field angle image quality, which has more value to apply.