Vignetting can occur due to the altered ray path , when the eyepiece ' s lenses are not large enough in diameter to allow all the rays to make it through 装饰图案可以发生是由于蚀变射线路径，当目镜的镜头是不是足够大的直径，让所有的光线，使之通过。
3.
For example , the geometric effect and vignetting are simulated with the synthetic method in which they are modeled with ray tracing and then simulated with pixel - based processing . the effects of detector noise on imaging are simulated with the three - dimension model . the theory of pixel transfer function is extended and developed , and microscanned images of four patterns are simulated with good results 本文具有如下几个突出特点：用光线追迹法分析建模，而用基于象素处理的综合方法，模拟了光学系统中的几何效应和渐晕现象；利用三维噪声模型，模拟了探测器噪声对图像质量的影响；对象素传递函数理论进行了扩展和延伸，给出四种工作模式的微扫描成像系统的象素传递函数的具体数学表达式，并利用这些表达式模拟了探测器的空间效应和微扫描成像的图像效果。
4.
On the base of studying imaging theory of lens , the imaging theory of laser confocal scanning microscopy was analyzed in detail in this paper , and the advancement of that the optical fiber was applied to the system was described ; on the base of completed the demonstration for whole project , the experiment scheme was designed ; the relationship between the main parameters of key devices and the resolution was deduced , and the requirements of coupling efficiency and vignetting effects to optical system was analyzed ; the design of optical system and the planar scanning controlling circuit was completed ; a new method was put forward to resolved the inherent non - liner scanning problem of the galvanometer scanner by using software liner controlling in circuit design , and the perfect planar scanning was realized ; at last the low noise , high multiple and non - distortion amplify circuit of photoelectric detector was completed 本文在透镜成像理论的基础上，系统、深入地分析了共焦扫描显微成像的机理，论述了应用单模光纤的激光共焦扫描显微成像系统的优点；进行了总体方案的论证，并设计确定了单模光纤激光共焦扫描显微成像系统的总体方案；从理论上推导分析了分辨率要求与试验系统中相关器件主要参数之间的关系，分析了系统耦合效率和渐晕现象对光学系统的设计要求；完成了方案中光学系统和二维扫描控制电路的设计，并在电路设计中采用了用软件解决检流计式光学扫描器(振镜)非线性问题的新方法，能够实现较为理想的二维模拟扫描；完成了高增益、低噪声和低失真的探测接收系统的设计和调试。
