Landmark digitization is essential in geometric morphometrics. It enables the quantification of biological shapes, such as facial structures. Traditional landmarking, which identifies specific anatomical points, can be complemented by semilandmarks when precise locations are challenging to define. However, manual placement of numerous landmarks is time-consuming and prone to human error, leading to inconsistencies across studies. To address this, we introduce FaceDig, an AI-powered tool designed to automate landmark placement with human-level precision, focusing on anatomically sound facial points. FaceDig is open-source and integrates seamlessly with analytical platforms like R and Python. It was trained using one of the largest and most ethnically diverse face dataset, applying a landmark configuration optimized for 2D enface photographs. Our results demonstrate that FaceDig provides reliable landmark coordinates, comparable to those placed manually by experts. The tool's output is compatible with the widely-used TpsDig2 software, which facilitates adoption and ensures consistency across studies. Users are advised to work with standardized facial images and visually inspect the results for potential corrections. Despite the growing preference for 3D morphometrics, 2D facial photographs remain valuable due to their cultural and practical significance. Future enhancements to FaceDig will include support for profile views, further expanding its utility. By offering a standardized approach to landmark placement, FaceDig promotes reproducibility in facial morphology research and provides a robust alternative to existing 2D tools.

Department of Philosophy and History of Science Faculty of Science Charles University Prague Czech Republic

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Antar, J. C. & Stephen, I. D. Facial shape provides a valid cue to sociosexuality in men but not women. DOI

Marcinkowska, U. M. et al. Changes in facial shape throughout pregnancy—a computational exploratory approach. DOI

Marcinkowska, U. M. & Holzleitner, I. J. Stability of women’s facial shape throughout the menstrual cycle. PubMed DOI PMC

Bookstein, F. L.

Wärmländer, S. K. T. S., Garvin, H., Guyomarc’h, P., Petaros, A. & Sholts, S. B. Landmark typology in applied morphometrics studies: what’s the point?. PubMed DOI

Rohlf, F. J. The tps series of software.

tpsDig2, Version 2.32. Department of Ecology and Evolution, State University of New York at Stony Brook (2021).

Kleisner, K. et al. African and European perception of African female attractiveness. DOI

Kleisner, K. et al. How and why patterns of sexual dimorphism in human faces vary across the world. PubMed DOI PMC

Kleisner, K. et al. Distinctiveness and femininity, rather than symmetry and masculinity, affect facial attractiveness across the world. DOI

Kleisner, K. Morphological uniqueness: the concept and its relationship to indicators of biological quality of human faces from equatorial Africa. DOI

Kleisner, K., Kočnar, T., Rubešová, A. & Flegr, J. Eye color predicts but does not directly influence perceived dominance in men. DOI

Fink, B. et al. Second to fourth digit ratio and face shape. PubMed DOI PMC

Mitteroecker, P., Windhager, S., Müller, G. B. & Schaefer, K. The morphometrics of" masculinity" in human faces. PubMed DOI PMC

Mitteroecker, P., Gunz, P., Windhager, S. & Schaefer, K. A brief review of shape, form, and allometry in geometric morphometrics, with applications to human facial morphology.

Schaefer, K., Fink, B., Mitteroecker, P., Neave, N. & Bookstein, F. L. Visualizing facial shape regression upon 2(nd) to 4(th) digit ratio and testosterone. PubMed

Schaefer, K. et al. Female appearance: Facial and bodily attractiveness as shape.

James Rohlf, F. & Marcus, L. F. A revolution morphometrics. PubMed DOI

Bookstein, F. L. Landmark methods for forms without landmarks: Morphometrics of group differences in outline shape. PubMed DOI

Gunz, P. & Mitteroecker, P. Semilandmarks: a method for quantifying curves and surfaces.

Rohlf, F. J. tpsSuper64, Version 2.06. (2021).

Lakshmi, A., Wittenbrink, B., Correll, J. & Ma, D. S. The India face set: international and cultural boundaries impact face impressions and perceptions of category membership. PubMed DOI PMC

Třebický, V., Havlíček, J., Roberts, S. C., Little, A. C. & Kleisner, K. Perceived aggressiveness predicts fighting performance in mixed-martial-arts fighters. PubMed DOI

Courset, R. et al. The Caucasian and North African French faces (CaNAFF) a face database. DOI

Danel, D. P., Dziedzic-Danel, A. & Kleisner, K. Does age difference really matter? Facial markers of biological quality and age difference between husband and wife. PubMed DOI

Marcinkowska, U. M. et al. Oxidative stress as a hidden cost of attractiveness in postmenopausal women. PubMed DOI PMC

Saribay, S. A., Tureček, P., Paluch, R. & Kleisner, K. Differential effects of resource scarcity and pathogen prevalence on heterosexual women’s facial masculinity preferences. PubMed DOI PMC

Pavlovič, O., Fiala, V. & Kleisner, K. Congruence in European and Asian perception of Vietnamese facial attractiveness, averageness, symmetry and sexual dimorphism. PubMed DOI PMC

Lugaresi, C.

LeCun, Y. et al. Backpropagation applied to handwritten zip code recognition. DOI

Peng, T., Li, M., Chen, F., Xu, Y. & Zhang, D. Learning efficient facial landmark model for human attractiveness analysis. DOI

Jones, A. L., Schild, C. & Jones, B. C. Facial metrics generated from manually and automatically placed image landmarks are highly correlated. DOI

Feng, Z.-H., Kittler, J., Awais, M., Huber, P. & Wu, X.-J. Wing loss for robust facial landmark localisation with convolutional neural networks. Preprint at 10.48550/arXiv.1711.06753 (2018).

Boudníková, O. & Kleisner, K. AI-generated faces show lower morphological diversity than real faces do. DOI