刀口法是一种利用人眼观察刀口在测量光路中形成的阴影图像，定性估计被测元件面形误差的检测技术，它方便易用，成本低廉，长期以来广泛应用于光学加工的检测中。随着数控加工技术在光学制造领域中应用日益广泛，实现刀口法的定量化，不仅符合数控光学加工技术的发展要求，同时还可以减少刀口阴影图像判读过程中人为因素的影响，发挥刀口法设备简单、抗干扰能力强、检测精度较高的优势。论文对刀口测量原理进行了分析，提出刀口定量测量方法，搭建实验平台，对光学元件进行定量化面形检测实验。测量球面反射镜是刀口法最广泛的应用，因此论文研究了具有环带误差的光学球面面形的数字化刀口法。对采集到的球面镜的刀口阴影图像进行数字化离散，将离散化后的图像按照像素宽度进行环带划分。利用刀口法可以准确判断每个环带对应的焦点位置的特点，测量得到每个环带相对于焦点的轴向偏移。通过建立环带面形误差与轴向偏移之间的关系，重构出光学球面面形。在此基础上，论文构建了采用虚拟刀口狭缝光源的数字化测量装置，利用该装置对球面典型光学元件开展了定量测量实验，并通过误差分析探讨了引入测量误差的因素及其对面形测量精度的影响。

The knife-edge method is a kind of Schlieren technique, by blocking out one part of a plane traversed by rays or diffracted light so that a shadow appears over the aberrated region. The operator’s eye, positioned just behind the knife-edge, views the shadow image and the errors on the surface are evaluated based on its principle. The main advantages of the knife-edge technique are its high sensitivity and simplicity, both in apparatus and in qualitative interpretation. So this method is wildly used in the optical shop test. However, with the applications of the computer controlled technology in optical polishing and grinding, the traditional knife-edge method cannot meet the demand of advanced optical manufacturing process. Therefore, a new method based on knife-edge test to quantitatively characterize local surface deformations of aspheric surface is developed, which can restrain the measurement errors introduced by human disturbance and maintain the advantages of the knife-edge method. By analyzing the principle of the knife-edge test, we brought up the digital knife-edge method. A set-up was designed and built to perform the measurements. Detecting spherical surfaces is the widespread application of the knife-edge method. So the digital method was used to measure the rotating deformations on the spherical surface, and the analysis was carried out on this measurement system. When the knife-edge was moving under the control of the stepping motor along the optical axis, the CCD camera record the shadow pictures. The model of the measure of the local deformations was built in accordance with the character of the light intensity distribution. The focus locations of the rings were determined according to the ring-shaped light intensity distribution and the spherical mirror with ring-shaped errors was rebuilt.The improved automatic experiment equipment with a virtual slit source was built to enhance the measuring accuracy and perform automatic measurement. After the deformations on the spherical surface was detected under the improved equipment, the error analysis of the test-measurement equipment was provided.