3D scanning method for foot medial arch description

This contribution introduces a new system for foot arch 3D scanning. The aim of this scanning is mainly automatic arch deformity detection and treatment efficiency evaluation in comparison among alternative therapeutic methods. Common arch deformities, which should be scaled and measured by the proposed method, are well known pes planus and pes cavus. Contemporary methods of their detection and description are based on plantogram analysis. Platogram is a poorly defined method of arch orthogonal projection to transversal plane, which could be influenced by the technical equipment used. Also the accuracy of its analysis could be affected by the method used and experience of the evaluator. Our method is based on 3D medial arch scanning by phase shift profilometry method utilization. Sets of periodical patterns are projected to the foot and captured by camera. Images are then segmented and continuous surface of the skin is mapped in space. On the basis of this depth map and colour image, a 3D model of the scanned arch could be created. The paper contains a deep theoretical analysis of applying the proposed method and recommendations how to set optimal parameters of a scanning system for this application.