Anthropometric Stereo Vision System for Measuring Foot Arches Angles in Three Dimensions

This article presents a 3-D anthropometric vision system, free of ionizing radiation for measuring the medial longitudinal arch (MLA) and longitudinal arch angle (LAA) of the foot, essential for evaluating foot arch disorders that can affect a person's lifestyle. Existing 2-D techniques for determining MLA based on anthropometric tests have limitations because they exclude important information about foot such as pronation, dorsiflexion, and rotation. To overcome these limitations, the proposed system uses stereo vision and a landmark detection algorithm to measure the 3-D MLA and LAA, considering the z -axis perpendicular to the sagittal plane. The proposed system is compared with a commercial LIDAR using a tridimensional grid (ground truth), obtaining a root mean square error (RMSE) of 1.2° for the proposed system and an RMSE of 4.8° for LIDAR. The proposed system offers several advantages over traditional techniques, including low error, 3-D measurement capabilities, and free of ionizing radiation. In addition, the system's application in human subjects showed a variability range between 3-D and 2-D measurements for MLA, which is consistent with previous research. Overall, the proposed system has the potential to improve the evaluation and treatment of foot arch disorders, thereby enhancing a person's quality of life.