Sharpness-statistics-based auto-focusing algorithm for optical ptychography
Abstract
In ptychography, the precise diffraction distance is critical to recover the object with high quality. An auto-focus algorithm is proposed which consists of a rough focusing step and a fine focusing step. These two steps make the sharpness statistics for the amplitude reconstructed from a single diffraction pattern and the amplitude retrieved with extended ptychographic iterative engine, respectively. Through the two focusing steps, the precise focal length is achievable at visible light wavelength. By using the refocused diffraction distance, we can acquire the ptychographic retrieved object with improved quality and resolution. The proposed algorithm has been verified by computer simulations and optical experiments, both in the ptychographic imaging of biological samples and the ptychographic microscopy of resolution targets.
- Publication:
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Optics and Lasers in Engineering
- Pub Date:
- May 2020
- DOI:
- 10.1016/j.optlaseng.2020.106053
- Bibcode:
- 2020OptLE.12806053M
- Keywords:
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- Optical ptychography;
- Auto-focusing algorithm;
- Microscopy;
- Experiment