Indonesian Journal of Electrical Engineering and Computer Science Vol. 17, No. 2, February 2020, pp. 594~605 ISSN: 2502-4752, DOI: 10.11591/ijeecs.v17.i2.pp594-605  594 Journal homepage: http://ijeecs.iaescore.com Image processing based foot plantar pressure distribution analysis and modeling Ali Hussein Sabry 1 , W. Z. Wan Hasan 2 , Mohd Nazim Mohtar 3 , Raja Mohd Kamil Raja Ahmad 4 , Hafiz Rashidi Ramli 5 , S. P. Ang 6 , Zainidi Haji Abdul Hamid 7 1 Automated Manufacturing Department, Al-Khawarizmi College of Engineering, University of Baghdad, Iraq 2,5 Electrical and Electronics Department, Faculty of Engineering, Universiti Putra Malaysia, Malaysia 2,3,4,5 Advanced Technology Institute (ITMA), Universiti Putra Malaysia, Malaysia 6,7 Electrical and Electronics Engineering, Faculty of Engineering, University Technology Brunei, Brunei Darul Salam Article Info ABSTRACT Article history: Received Jun 1, 2019 Revised Aug 2, 2019 Accepted Aug 16, 2019 Although many equipments and techniques are available for plantar pressure analysis to study foot pressure distributions, there is still a need for mathematical modelling references to compare the acquired measurements. In order to derive formulas in this concern, this research proposes a measurement-based method which adopts the reference measured parameters such as; the weight of a subject, contact-area size, age, and the pressure level distribution over a plantar image captured by the EMED plantar pressure system. The proposed analysis and algorithm were verified by a group 79 volunteers through data collection with four various measurement conditions. Three mathematical modelling equations have been proposed that describe the relationships between the foot plantar pressure leve ls and the subject’s body mass, foot size, and age. The modelling of foot plantar pressure could be useful for various applications such as gait analysis, hospitals, clinics, custom shoe making, and early detection of ulceration in the case of diabetic patients. Keywords: Data analysis Foot plantar pressure Image processing Mathematical modeling Copyright © 2020 Institute of Advanced Engineering and Science. All rights reserved. Corresponding Author: Hafiz Rashidi Ramli, Department of Electrical and Computer Engineering, Faculty of Engineering, Universiti Putra Malaysia, Serdang, 43400 Selangor, Malaysia. Email: hrhr@upm.edu.my 1. INTRODUCTION Plantar pressure distribution analysis is an increasingly popular research area in the study of foot diagnosis and gait evaluation. There are many types of plantar pressure measurement systems that are commercially available and have different constraints such as the high cost, and the data linkages as collected by the computer [1]. Previous studies have classified plantar pressure measuring equipments according to the sensing method used: images or electronic sensor [2, 3]. The ink-based plantar pressure system may not be able to acquire data dynamically, whereas the image-based system derives the plantar pressure distributions from the light intensity of a grayscale image captured through a camera fixed within [4]. Despite some active research in the area circa 1980s, the use of such devices were not widespread due to the limitations in resolution and system cost. However, information extracted from captured images are considered as a useful parameter in gait analysis. One study described the differences for a joint ankle's angles through the use of static and dynamic plantar images [5]. A relationship between foot structure and the static balance system is was studied to investigate a child’s footprint image in [6]. Based also on the image measurements, [7] found the