During contraction and stretching, muscles change shape and size, and produce a deformation of skin tissues and a modification of the body segment shape. In human motion analysis, it is very important to take into account these phenomena. The aim of this work is the evaluation of skin and muscular deformation, and the modeling of body segment elastic behavior obtained by analysing video sequences that capture a muscle contraction. The soft tissue modeling is accomplished by using triangular meshes that automatically adapt to the body segment during the execution of a static muscle contraction. The adaptive triangular mesh is built on reference points whose motion is estimated by using non linear operators. Experimental results, obtained by applying the proposed method to several video sequences, where biceps brachial isometric contraction was present, show the effectiveness of this technique.
Carli, M., Goffredo, M., Schmid, M., & Neri, A. (2006). Study of muscular deformation based on surface slope estimation. In SPIE Proceedings Vol. 6064 Image Processing: Algorithms and Systems, Neural Networks, and Machine Learning (pp.271-278) [10.1117/12.642813].