Abstract

Vision based articulated hand pose estimation and hand shape classification are challenging problems. This paper proposes novel algorithms to perform these tasks using depth sensors. In particular, we introduce a novel randomized decision forest (RDF) based hand shape classifier, and use it in a novel multi–layered RDF framework for articu- lated hand pose estimation. This classifier assigns the input depth pixels to hand shape classes, and directs them to the corresponding hand pose estimators trained specifically for that hand shape. We introduce two novel types of multi–layered RDFs: Global Expert Network (GEN) and Local Expert Network (LEN), which achieve significantly better hand pose estimates than a single–layered skeleton estimator and generalize better to previously unseen hand poses. The novel hand shape classifier is also shown to be accurate and fast. The methods run in real–time on the CPU, and can be ported to the GPU for further increase in speed.