Recognition of Hand Posture Based on a Point Cloud Descriptor and a Feature of Extended Fingers

Our work involves hand posture recognition based on 3D data acquired by the KinectTM sensor in the form of point clouds. We combine a descriptor built on the basis of the Viewpoint Feature Histogram (VFH) with additional feature describing the number of extended fingers. First, we extract a region corresponding to the hand and then a histogram of the edge distances from the palm center is built. Based on quantized version of the histogram we calculate the number of extended fingers. This information is used as a first feature describing the hand which, together with VFH-based features, form the feature vector. Before calculating VFH we rotate the hand making our method invariant to hand rotations around the axis perpendicular to the camera lens. Finally, we apply nearest neighbor technique for the posture classification. We present results of crossvalidation tests performed on a representative dataset consisting of 10 different postures, each shown 10 times by 10 subjects. The comparison of recognition rate and mean computation time with other works performed on this dataset confirms the usefulness of our approach.