基于CMOS的调制传递函数测试系统的研究

【作者】 樊翔；

【导师】 倪旭翔；

【作者基本信息】 浙江大学 ， 测试计量技术及仪器， 2004， 硕士

【摘要】 光学传递函数是目前评价光学系统成像质量最客观、最有效的方法之一，广泛地应用于光学系统设计的过程控制和光学成像系统的像质评价与检测中。本文详细讨论了一种采用全新计算方法，并以CMOS为图像接收器件的调制传递函数测量系统。 本系统以傅立叶光学为依据，以刀口为目标物，以CMOS为图像接收器件，采用独特的算法，从刀口图像的灰度直方图中获得其刀口边缘函数，经微分和FFT运算，得到待测镜头的MTF，从而得知其成像品质。本系统测量的空间频率范围和焦距范围都比较大。 论文阐述光学传递函数测量的原理，分析了各种测量方法，描述国内外同类仪器的发展现状，总结今后发展趋势，重点介绍了系统的硬件和软件的组成。硬件部分主要包括光源、图像传感器、图像采集设备等，并详细介绍了系统硬件的完善部分，即通过与计算机的双向通信，实现了9个CMOS的选通控制，从而提高全视场MTF的测量精度。软件设计方面，提出了一种独特的计算边缘扩展函数的方法，以及各种数据处理的方法。最后介绍了在Matlab平台下开发的用户界面，以及具体的实验结果，并分析了产生误差的各种原因。 本论文也对系统以后的改进作了一些探讨。更多还原

【Abstract】 OTF, one of the most objective and effective methods that are proposed to evaluate the imaging quality of the optical system, is extensively used in the process control of the optical system design and the imaging quality evaluation and detection of the optical imaging system. In this paper the MTF system, using a new counting method and CMOS sensor as device for image reception, is discussed in detail.The system is on the basis of Fourier Optics. By using knife edge as object, CMOS sensor as device for image reception, we get edge spread function from the image histogram and use differential operation and FFT to achieve MTF of the lens, then its image quality is obtained. The system is with a broad spatial frequency and focus ranges.This paper introduces the theory of OTF testing, analyzes various testing methods and the hardware and the software of the proposed system are expatiated. The hardware mainly includes light, image sensor, image collector. The improvement of hardware, which can realize gate control of the 9 CMOS by the two-way communication with the computer, and can improve the MTF measurement accuracy of the whole field of view, is introduced in detail. In the software design, a particular method of counting ESF is provided and other related data handling methods are also introduced. In the end, the paper gives the outline of the user interface based on Matlab, achieves the experimental results and analyzes the reasons of making errors.The paper also discusses how to improve the performance of the proposed testing system in the future.更多还原