为了研究采用星点法的小视场镜头畸变测量，选择星点像中心判读和星点选择两方面作为切入点。针对星点像中心判读，在对比了传统的质心算法的基础上，采用将最大类间方差算法与重心计算相结合的方法以提高星点定位的准确性。针对星点选择，为保证星点定位的稳定性以及畸变计算的精准度，用实验方法分析了星点大小的不同对于畸变测量中星点像定位稳定性的影响，选择整个视场内同一水平线下不同位置的y坐标值均方差为1/71像元的星点进行实验，通过实验测得了实际镜头的绝对畸变和相对畸变。结果表明，该方法测得的镜头畸变精度高，可达到航天级应用要求。

In order to measure the distortion of the narrow field of view (NFOV) lens by means of star point method, both star point center orientation and star size, affecting the accuracy of the distortion measurement, were studied. First of all, in order to improve the star positioning accuracy, Otsu algorithm and the barycenter calculation were combined to calculate the location of star point. At the same time, the calculated results were compared with the traditional centroid algorithm. Then, the effect of the star size on the stability of the star point positioning was analyzed in the experiments. Finally, the absolute and relative distortion of the lens was measured for the star points whose mean square error of coordinates is 1/71 pixel. The results show that the distortion of the NFOV lens can be measured with high precision and this method can meet space application.