Monitoring algorithm of tilt angle based on sub-block plane fitting for high-resolution imaging

The limitation of mechanical structure and misoperations can result in a small tilt angle formed by the sample and the focal plane, which will decrease the resolution of the imaging system. Moreover, the small tilt angle is difficult to be observed. In order to solve this problem, a monitoring algorithm of tilt angle based on sub-block plane fitting for high-resolution imaging systems has been proposed, which is used to measure the initial angle of most 2D samples before imaging and assist users to determine the tilt degree of the sample. Experiments demonstrate that the proposed method can measure the tilt angle with a high measurement precision of 0.007 degrees and a low residual tilt angle of 0.004 degrees, indicating that the algorithm has high measurement precision and stability. Further results show that the quality of the image will be improved by 20%-27% when the tilt angle is 0.3056 degrees, which means that the small degree of tilt of the sample can seriously damage the image quality. Therefore, the study of tilt angle measurement has great significance for high-resolution imaging systems. (C) 2019 Optical Society of America