# Image Reconstruction Using Autofocus in Single-Lens System
## 4 Conclusions  
In this work, we insert a diffuser into the single-lens CDI system to improve the accuracy and robustness of the autofocus algorithm. Our proposed SCIE algorithm can reconstruct samples with fast iteration speed and robustness in a single-lens CDI. We proposed the use of NMSE and NSSIM in two-unknown-distance autofocusing with taking the pixel mean value of the reconstructed image data set as the reference input. The 2D CEF curves show good unimodality. This paper provides new strategies for reconstruction samples and auto-focusing in the single-lens imaging system, which provides imaging solutions for CDI systems with a lens. Experiments, methodology and writing, X.Z. ; investigation, X.W. ; visualization, Y.J. ; investigation, Y.L. ; review and editing, S.L. ; review, editing and supervision, Z.L. All authors have read and agreed to the published version of the manuscript. National Natural Science Foundation of China (11874132, 61975044, 12074094); Interdisciplinary Research Foundation of HIT (IR2021237). Not applicable. Figure 11: Auto-focusing curves and sample reconstruction results. (**a1–a3**) and (**b1–b3**) are the rough auto-focusing curves of NMSE and NSSIM, respectively; (**c1–c3**) and (**d1–d3**) are the fine auto-focusing curves of NMSE and NSSIM, respectively; (**c1,e2,f1,f2**) are the reconstruction results using the quasi-focal distances from (**c1,d1**), respectively; (**g**) pixel contrast curves. The white bar corresponds to 200 μm. Figure 10: CEFs experimental results of simultaneous scanning of object and image distances: (**a1–a9**) display the CEF curves under coherent illumination; (**b1–b9**) display the CEF curves under speckle illumination. **Informed Consent Statement:** Not applicable. **Data Availability Statement:** Data underlying the results presented in this paper are not publicly available at this time but may be obtained from the authors upon reasonable request. **Acknowledgments:** The authors would like to thank [PERSON] for his writing advice, [PERSON] for his experimental and methodological guidance, and [PERSON] and [PERSON] for their suggestions on the revision of the article. The authors would also like to thank the editors and the three reviewers who made valuable comments that helped us improve this paper. **Conflicts of Interest:** The authors declare no conflict of interest. * _[PERSON] et al. (1997)_ [PERSON]; [PERSON]; [PERSON]; [PERSON]; [PERSON]; [PERSON] Evaluation of autofocus functions in molecular cytogenetic analysis. _J. Microsc._**1997**, _188_, 264-272. [CrossRef]
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