2026-10-13T16:12:36Z https://www.scidb.cn/oai

10.57760/sciencedb.35446 2026-01-16T14:33:32Z

2026-01-16 High Precision Focus Error Detection Technology Based on the Astigmatic Method doi:10.57760/sciencedb.35446 en To improve the detection accuracy of astigmatism-based defocus detection systems, it is crucial to enhance the stability of the four-quadrant detector output signal. This study proposes a joint filtering method that integrates Kalman filtering with wavelet threshold denoising to suppress signal disturbances. Kalman filtering is first employed to mitigate low-frequency fluctuations, after which wavelet threshold denoising is applied to reduce the high-frequency residual errors introduced by the Kalman filter. This combination achieves effective suppression of both low- and high-frequency interferences. Experimental results show that the joint filtering method reduces the root-mean-square error and peak-to-peak error of the acquired signal by more than 70%, significantly improving signal stability. The minimum resolvable displacement is improved from 88 nm to 38 nm, corresponding to a 56.8% increase in detection accuracy. Compared with conventional methods, the proposed digital filtering strategy not only simplifies the optical system but also enhances the robustness and accuracy of signal acquisition. defocus detection; astigmatism method; kalman filter; wavelet threshold denoising; joint filtering zhang Ruan Hao Zhao Miao Tian Geng PUBLIC https://creativecommons.org/licenses/by-nc-nd/4.0/ dataset Science Data Bank