Laplacian-based focus measure allows rapid focus estimation of annular regions in gray-scale images

Masetti, Ettore and Giardini, Mario Ettore and Ruggeri, Marco and Rovati, Luigi; (2023) Laplacian-based focus measure allows rapid focus estimation of annular regions in gray-scale images. In: 2023 IEEE International Instrumentation and Measurement Technology Conference (I2MTC). IEEE International Instrumentation and Measurement Technology Conference . IEEE, MYS. ISBN 9781665453837 (https://doi.org/10.1109/i2mtc53148.2023.10176114)

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Abstract

Important ophthalmic imaging techniques, such as fundus camera imaging, utilize light sources that need to be focused on an annular section of an eye surface. In order to be performed dynamically, this requires real-time control of the focus plane of the illumination optics. When considering adaptive focusing in ophthalmic instruments, liquid lenses represent the best compromise in terms of tunability, tuning range, compactness, numerical aperture, and speed. In recent years, several compact eye imaging devices using liquid lenses have been described in the literature. These would benefit from low computational complexity algorithms for adaptive local auto-focus on an annular region, to allow the illumination optics to be controlled by low-cost and low-power electronics. In this paper, we propose a novel radial-focus evaluation method based on a revised version of a more traditional Laplacian-based focus estimator. This radial focus evaluation is targeted to focusing annular sections of an image, with the advantage of a drastic reduction of computational complexity.

ORCID iDs

Masetti, Ettore, Giardini, Mario Ettore ORCID logoORCID: https://orcid.org/0000-0003-4849-9683, Ruggeri, Marco and Rovati, Luigi;
  • Item type:Book Section
    ID code:86297
    Dates:
    Date
    Event
    13 July 2023
    Published
    13 January 2023
    Accepted
    Notes:© 2023 IEEE. Personal use of this material is permitted. Permission from IEEE must be obtained for all other uses, in any current or future media, including reprinting /republishing this material for advertising or promotional purposes, creating new collective works, for resale or redistribution to servers or lists, or reuse of any copyrighted component of this work in other works.
    Subjects:Technology > Electrical engineering. Electronics Nuclear engineering > Electrical apparatus and materials
    Department:Faculty of Engineering > Biomedical Engineering
    Depositing user: Pure Administrator
    Date deposited:27 Jul 2023 10:30
    Last modified:11 Nov 2024 15:33
    URI:https://strathprints.strath.ac.uk/id/eprint/86297
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