Large range nano autofocus method based on differential centroid technique

Du, Jialin; Sun, Song; Li, Fanxing; Jiang, Jixin; Yan, Wei; Wang, Simo; Tian, Peng

doi:10.1016/j.optlastec.2022.109015

Cited by 5 publications

(1 citation statement)

References 24 publications

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“…Nevertheless, it's crucial to acknowledge that the optics-based autofocus method might be susceptible to environmental factors that could potentially impact the accuracy of the focus, as indicated by some studies [15]. Currently, numerous researchers are dedicated to enhancing the accuracy of optical autofocus, whether through improving hardware components [16,17] or employing advanced image processing techniques [1,[18][19][20][21][22]. Despite the beneficial aspects of various methods, it has been observed that, regardless of the means used to improve autofocus accuracy, the light spot detected by the light sensor may undergo significant distortion when the test object is near the focus point.…”

Section: Introductionmentioning

confidence: 99%

Design and Experimental Validation of an Optical Autofocusing System with Improved Accuracy

Hung,

Tu,

Hsu

et al. 2023

Photonics

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This study proposes a modified optical design to improve the issue of autofocus accuracy in existing optical systems. The proposed system uses lens offset to convert incident light into non-parallel light, achieving a focus shift and avoiding severe deformation of the light spot near the focal point of the objective lens. Based on triangulation theory and optical focusing theories such as the centroid method, the proposed optical design improves the shortcomings of existing technology. Experimental results demonstrate that the proposed optical autofocusing system has better autofocus accuracy than traditional systems while also reducing the difficulty of image processing. In summary, the proposed optical system is not only an effective autofocusing technology but also a highly valuable optical inspection and industrial application technology. This system has broader application and development opportunities for future research and practice.

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