Continuous gesture recognition from articulated poses

This paper addresses the problem of continuous gesture recognition from articulated poses. Unlike the common isolated recognition scenario, the gesture boundaries are here unknown, and one has to solve two problems: segmentation and recognition. This is cast into a labeling framework, namely every site (frame) must be assigned a label (gesture ID). The inherent constraint for a piece-wise constant labeling is satisfied by solving a global optimization problem with a smoothness term. For efficiency reasons, we suggest a dynamic programming (DP) solver that seeks the optimal path in a recursive manner. To quantify the consistency between the labels and the observations, we build on a recent method that encodes sequences of articulated poses into Fisher vectors using short skeletal descriptors. A sliding window allows to frame-wise build such Fisher vectors that are then classified by a multi-class SVM, whereby each label is assigned to each frame at some cost. The evaluation in the ChalearnLAP-2014 challenge shows that the method outperforms other participants that rely only on skeleton data. We also show that the proposed method competes with the top-ranking methods when colour and skeleton features are jointly used.