Mohd Tamrin, Mohd Izzuddin and Turaev, Sherzod and Sase, Takumi and Che Azemin, Mohd. Zulfaezal and Tengku Sembok, Tengku Mohd (2026) Canthus-scaled 468-landmark FaceMesh framework for pupillary distance estimation using nested AutoML calibration. International Journal of Advanced Computer Science and Applications, 17 (6). pp. 438-445. ISSN 2158-107X E-ISSN 2156-5570
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Abstract
Pupillary distance (PD) is an important ocular measurement for optical dispensing and vision-related applications, but standard MediaPipe FaceMesh outputs do not provide true pupil-centre or iris-boundary landmarks when only the 468-landmark representation is available. This study proposes a canthus-scaled 468-landmark framework for estimating PD using facial landmarks and Malay young-adult normative palpebral fissure width. A dataset of 44 subjects was used, where each record contained ground-truth PD and 1,404 coordinate values representing 468 FaceMesh landmarks in three dimensions. Since true pupil centres were unavailable, medial and lateral canthus landmarks were used to construct eye-centre proxies and to compute a subject-specific millimetre scale. A direct canthus-scaled proxy was first evaluated as a deterministic baseline, after which canthus-scaled geometric features were used in a nested AutoML calibration framework. Model development used repeated nested cross-validation, with an outer repeated 5-fold design and an inner 4-fold model-selection loop. The direct proxy achieved a mean absolute error (MAE) of 4.26 mm and showed systematic overestimation. The calibrated nested AutoML model improved performance, achieving a subject-level MAE of 3.510 mm, root mean squared error of 4.22 mm, a bias of −0.08 mm, and 75.0% of predictions within ±5 mm. The calibrated nested AutoML model improved overall error and reduced systematic bias compared with the direct canthus-scaled proxy. However, the Bland–Altman limits of agreement remained wide, indicating that the proposed method should be interpreted as an approximate proxy-based estimation approach rather than a substitute for clinical pupillometer- or ruler-based PD measurement. The framework is most relevant for research settings or datasets where only standard 468-landmark FaceMesh data are available, and iris-refined landmarks are absent.
| Item Type: | Article (Journal) |
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| Uncontrolled Keywords: | Pupillary distance, MediaPipe FaceMesh, facial landmarks, canthus scaling, palpebral fissure width, AutoML, nested cross-validation, computer vision |
| Subjects: | T Technology > TK Electrical engineering. Electronics Nuclear engineering > TK7800 Electronics. Computer engineering. Computer hardware. Photoelectronic devices > TK7885 Computer engineering |
| Kulliyyahs/Centres/Divisions/Institutes (Can select more than one option. Press CONTROL button): | Kulliyyah of Allied Health Sciences Kulliyyah of Allied Health Sciences > Department of Optometry and Visual Science Kulliyyah of Information and Communication Technology Kulliyyah of Information and Communication Technology |
| Depositing User: | Mohd Izzuddin Mohd Tamrin |
| Date Deposited: | 06 Jul 2026 08:56 |
| Last Modified: | 06 Jul 2026 08:56 |
| Queue Number: | 2026-07-Q3937 |
| URI: | http://irep.iium.edu.my/id/eprint/129759 |
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