Assessment of lower limb joint kinematics using a 2-D hybrid markerless approach applied to a video camcorder acquisition

In this study, a 2-D hybrid markerless technique is proposed to estimate the lower limb joint kinematics from data recorded using a video camcorder. The presented markerless methodology is defined as hybrid because garments like high-cut underwear and ankle socks were used as \u201csegmental markers\u201d. High-cut underwear contributed in defining the pelvis segment and ankle socks are used for the definition of the foot segment. The method was applied to a video sequence acquired with a video camcorder. The method was validated by using a stereophotogrammetric marker-based system. Correlation and Root Mean Square Deviation (RMSD) of the joint kinematics estimates obtained with the two techniques were found to be similar. The proposed hybrid technique can be considered as an easy-to-configure and affordable alternative to marker-based photogrammetric systems for the estimation of the lower limb joint kinematics