journal article·2025-07-26Open access

Evaluating Skin Tone Fairness in Convolutional Neural Networks for the Classification of Diabetic Foot Ulcers

Sara Seabra Reis, Luis Pinto-Coelho, Maria Carolina Sousa, Mariana Neto, Marta Silva, Miguela Sequeira

Applied Sciences· Volume 15· Issue 15

Abstract

The present paper investigates the application of convolutional neural networks (CNNs) for the classification of diabetic foot ulcers, using VGG16, VGG19 and MobileNetV2 architectures. The primary objective is to develop and compare deep learning models capable of accurately identifying ulcerated regions in clinical images of diabetic feet, thereby aiding in the prevention and effective treatment of foot ulcers. A comprehensive study was conducted using an annotated dataset of medical images, evaluating the performance of the models in terms of accuracy, precision, recall and F1-score. VGG19 achieved the highest accuracy at 97%, demonstrating superior ability to focus activations on relevant lesion areas in complex images. MobileNetV2, while slightly less accurate, excelled in computational efficiency, making it a suitable choice for mobile devices and environments with hardware constraints. The study also highlights the limitations of each architecture, such as increased risk of overfitting in deeper models and the lower capability of MobileNetV2 to capture fine clinical details. These findings suggest that CNNs hold significant potential in computer-aided clinical diagnosis, particularly in the early and precise detection of diabetic foot ulcers, where timely intervention is crucial to prevent amputations.
Source: crossref · Quality: baseline

Research context

OpenAlex topics: Diabetic Foot Ulcer Assessment and Management · Non-Invasive Vital Sign Monitoring · Infrared Thermography in Medicine

SciVX discovery tags are terminology-based. OpenAlex topics are source-provided classifications.

Affiliations

ISEP, Polytechnic of Porto, 4249-015 Porto, Portugal

CIETI, ISEP, Polytechnic of Porto, 4249-015 Porto, Portugal

INESC TEC—Institute for Systems and Computer Engineering Technology and Science, 4200-465 Porto, Portugal

References (53)

Show source-provided references
1. Diabetes Mellitus: Causas, Tratamento e Prevenção/Diabetes Mellitus: Causes, Treatment and Prevention10.34117/bjdv8n2-107 ↗
2. Pathophysiology of Diabetes: An Overview10.4103/ajm.ajm_53_20 ↗
4. Cholesterol Metabolism, Pancreatic β-Cell Function and Diabetes10.1016/j.bbadis.2019.04.012 ↗
5. Genetics of Diabetes Mellitus and Diabetes Complications10.1038/s41581-020-0278-5 ↗
6. Boulton, A.J.M., Armstrong, D.G., Hardman, M.J., Malone, M., Embil, J.M., Attinger, C.E., Lipsky, B.A., Aragón-Sánchez, J., Li, H.K., and Schultz, G. (2020). Diagnosis and Management of Diabetic Foot Infections, American Diabetes Association.10.2337/db2020-01 ↗
7. Plantar Pressure Thresholds as a Strategy to Prevent Diabetic Foot Ulcers: A Systematic Review10.1016/j.heliyon.2024.e26161 ↗
8. (2025, June 22). In-Shoe Plantar Pressure Measurement Technologies for the Diabetic Foot: A Systematic Review: Heliyon. Available online: https://www.cell.com/heliyon/fulltext/S2405-8440(24)05703-7.
9. Ansari, P., Akther, S., Khan, J.T., Islam, S.S., Masud, M.S.R., Rahman, A., Seidel, V., and Abdel-Wahab, Y.H.A. (2022). Hyperglycaemia-Linked Diabetic Foot Complications and Their Management Using Conventional and Alternative Therapies. Appl. Sci., 12.10.3390/app122211777 ↗
10. Castro-Martins, P., Marques, A., Pinto-Coelho, L., Fonseca, P., and Vaz, M. (2025). A Portable Insole System for Actively Controlled Offloading of Plantar Pressure for Diabetic Foot Care. Sensors, 25.10.3390/s25123820 ↗
11. (2021, December 22). World Health Organization Diabetes Fact Sheet. Available online: https://www.who.int/news-room/fact-sheets/detail/diabetes.
12. Diabetic Foot Ulcer Classifications: A Critical Review10.1002/dmrr.3272 ↗
13. Castro-Martins, P., Pinto-Coelho, L., and Campilho, R.D.S.G. (2024). Calibration and Modeling of the Semmes–Weinstein Monofilament for Diabetic Foot Management. Bioengineering, 11.10.20944/preprints202404.1560.v1 ↗
14. Prevention of Diabetic Foot Ulcer
15. Costa, T., Coelho, L., and Silva, M.F. (2022). Automatic Segmentation of Monofilament Testing Sites in Plantar Images for Diabetic Foot Management. Bioengineering, 9.10.3390/bioengineering9030086 ↗
16. Five Year Mortality and Direct Costs of Care for People with Diabetic Foot Complications Are Comparable to Cancer10.1186/s13047-020-00383-2 ↗
17. Pinto-Coelho, L. (2023). How Artificial Intelligence Is Shaping Medical Imaging Technology: A Survey of Innovations and Applications. Bioengineering, 10.10.20944/preprints202311.1366.v1 ↗
18. Das, S.K., Roy, P., Singh, P., Diwakar, M., Singh, V., Maurya, A., Kumar, S., Kadry, S., and Kim, J. (2023). Diabetic Foot Ulcer Identification: A Review. Diagnostics, 13.10.3390/diagnostics13121998 ↗
19. Fine-Grained Diabetic Wound Depth and Granulation Tissue Amount Assessment Using Bilinear Convolutional Neural Network10.1109/ACCESS.2019.2959027 ↗
20. Wang, C., Yu, Z., Long, Z., Zhao, H., and Wang, Z. (2024). A Few-Shot Diabetes Foot Ulcer Image Classification Method Based on Deep ResNet and Transfer Learning. Sci. Rep., 14.10.1038/s41598-024-80691-w ↗
21. DFU_QUTNet: Diabetic Foot Ulcer Classification Using Novel Deep Convolutional Neural Network10.1007/s11042-019-07820-w ↗
22. Yap, M.H., Cassidy, B., Pappachan, J.M., O’Shea, C., Gillespie, D., and Reeves, N.D. (2021, January 27–30). Analysis Towards Classification of Infection and Ischaemia of Diabetic Foot Ulcers. Proceedings of the 2021 IEEE EMBS International Conference on Biomedical and Health Informatics (BHI), Athens, Greece.10.1109/BHI50953.2021.9508563 ↗
23. Diabetic Foot Ulcer Ischemia and Infection Classification Using EfficientNet Deep Learning Models10.1109/OJEMB.2022.3219725 ↗
24. Anisuzzaman, D.M., Patel, Y., Rostami, B., Niezgoda, J., Gopalakrishnan, S., and Yu, Z. (2022). Multi-Modal Wound Classification Using Wound Image and Location by Deep Neural Network. Sci. Rep., 12.10.1038/s41598-022-21813-0 ↗
25. Alqahtani, A., Alsubai, S., Rahamathulla, M.P., Gumaei, A., Sha, M., Zhang, Y.-D., and Khan, M.A. (2023). Empowering Foot Health: Harnessing the Adaptive Weighted Sub-Gradient Convolutional Neural Network for Diabetic Foot Ulcer Classification. Diagnostics, 13.10.3390/diagnostics13172831 ↗
26. Sathya Preiya, V., and Kumar, V.D.A. (2023). Deep Learning-Based Classification and Feature Extraction for Predicting Pathogenesis of Foot Ulcers in Patients with Diabetes. Diagnostics, 13.10.3390/diagnostics13121983 ↗
27. Real-Time Diabetic Foot Ulcer Classification Based on Deep Learning & Parallel Hardware Computational Tools10.1007/s11042-024-18304-x ↗
28. Diabetic Foot Ulcer Classification Assessment Employing an Improved Machine Learning Algorithm10.1177/09287329241296417 ↗
29. Skin Pigmentation Impacts the Clinical Diagnosis of Wound Infection: Imaging of Bacterial Burden to Overcome Diagnostic Limitations10.1007/s40615-023-01584-8 ↗
30. Exploring Physiological Differences in Injury Response by Skin Tone: A Scoping Review10.1016/j.jtv.2025.100871 ↗
31. The DFUC 2020 Dataset: Analysis Towards Diabetic Foot Ulcer Detection10.17925/EE.2021.17.1.5 ↗
32. (2025, July 16). Pictures of Wounds and Surgical Wound Dressings. Available online: https://www.medetec.co.uk/files/medetec-image-databases.html.
33. Robust Application of New Deep Learning Tools: An Experimental Study in Medical Imaging10.1007/s11042-021-10942-9 ↗
34. Alzubaidi, L., Fadhel, M.A., Al-Shamma, O., Zhang, J., Santamaría, J., Duan, Y., and Oleiwi, S.R. (2020). Towards a Better Understanding of Transfer Learning for Medical Imaging: A Case Study. Appl. Sci., 10.10.3390/app10134523 ↗
35. Schwartz, R., Vassilev, A., Greene, K.K., Perine, L., Burt, A., and Hall, P. (2022). Towards a Standard for Identifying and Managing Bias in Artificial Intelligence.10.6028/NIST.SP.1270 ↗
36. A Survey on Dataset Quality in Machine Learning10.1016/j.infsof.2023.107268 ↗
37. The Validity and Practicality of Sun-Reactive Skin Types I through VI10.1001/archderm.1988.01670060015008 ↗
38. Skin Colour Typology and Suntanning Pathways10.1111/j.1467-2494.1991.tb00561.x ↗
39. Individual Typology Angle and Fitzpatrick Skin Phototypes Are Not Equivalent in Photodermatology10.1111/php.13562 ↗
40. Fijałkowska, M., Koziej, M., Żądzińska, E., Antoszewski, B., and Sitek, A. (2022). Assessment of the Predictive Value of Spectrophotometric Skin Color Parameters and Environmental and Behavioral Factors in Estimating the Risk of Skin Cancer: A Case–Control Study. J. Clin. Med., 11.10.3390/jcm11112969 ↗
41. Groh, M., Harris, C., Soenksen, L., Lau, F., Han, R., Kim, A., Koochek, A., and Badri, O. (2021, January 19–25). Evaluating Deep Neural Networks Trained on Clinical Images in Dermatology with the Fitzpatrick 17k Dataset. Proceedings of the 2021 IEEE/CVF Conference on Computer Vision and Pattern Recognition Workshops (CVPRW), Nashville, TN, USA.10.1109/CVPRW53098.2021.00201 ↗
42. İsmail Mendi, B., Kose, K., Fleshner, L., Adam, R., Safai, B., Farabi, B., and Atak, M.F. (2024). Artificial Intelligence in the Non-Invasive Detection of Melanoma. Life, 14.10.20944/preprints202410.0984.v1 ↗
43. Rathore, P.S., Kumar, A., Nandal, A., Dhaka, A., and Sharma, A.K. (2025). A Feature Explainability-Based Deep Learning Technique for Diabetic Foot Ulcer Identification. Sci. Rep., 15.10.1038/s41598-025-90780-z ↗
44. Abadi, M., Agarwal, A., Barham, P., Brevdo, E., Chen, Z., Citro, C., Corrado, G.S., Davis, A., Dean, J., and Devin, M. (2016). TensorFlow: Large-Scale Machine Learning on Heterogeneous Distributed Systems. arXiv.
45. Simonyan, K., and Zisserman, A. (2015). Very Deep Convolutional Networks for Large-Scale Image Recognition. arXiv.
46. Sandler, M., Howard, A., Zhu, M., Zhmoginov, A., and Chen, L.-C. (June, January ). MobileNetV2: Inverted Residuals and Linear Bottlenecks 2019. Proceedings of the 2018 IEEE/CVF Conference on Computer Vision and Pattern Recognition, Salt Lake City, UT, USA.10.1109/CVPR.2018.00474 ↗
47. Deep Learning: Definition and Perspectives for Thoracic Imaging10.1007/s00330-019-06564-3 ↗
48. Batch Normalization: Accelerating Deep Network Training by Reducing Internal Covariate Shift
49. Liu, Y., Agarwal, S., and Venkataraman, S. (2021). Autofreeze: Automatically Freezing Model Blocks to Accelerate Fine-Tuning. arXiv.
50. Bhatt, D., Patel, C., Talsania, H., Patel, J., Vaghela, R., Pandya, S., Modi, K., and Ghayvat, H. (2021). CNN Variants for Computer Vision: History, Architecture, Application, Challenges and Future Scope. Electronics, 10.10.3390/electronics10202470 ↗
51. Nikbakhtsarvestani, F., Ebrahimi, M., and Rahnamayan, S. (2023, January 1–4). Multi-Objective ADAM Optimizer (MAdam). Proceedings of the 2023 IEEE International Conference on Systems, Man, and Cybernetics (SMC), Maui, HI, USA.10.1109/SMC53992.2023.10394533 ↗
52. Intelligent Medical Detection and Diagnosis Assisted by Deep Learning10.54254/2755-2721/64/20241356 ↗
53. Zhang, H., and Ogasawara, K. (2023). Grad-CAM-Based Explainable Artificial Intelligence Related to Medical Text Processing. Bioengineering, 10.10.3390/bioengineering10091070 ↗