4th WCSET-2015 at Japan
Applied Sciences and Engineering:
Title:
A Single Depth Sensor based Human activity recognition
via Deep Belief Network
Authors:
S. B. Nam, S. U. Park, J. H. Park, T. S. Kim
Abstract: Human
activity recognition (HAR) from videos is a challenging
work towards various important application domains, such
as human-machine interaction, interactive entertainment,
smart surveillance, etc. In this paper, we present a
novel system to recognize human activities via Deep
Belief Network (DBN). We have employed Restricted
Boltzmann Machine (RBM) over the commonly used Hidden
Markov Models (HMMs). We train RBM with the
spatio-temporal features of human activities (i.e,
pre-training) via a contrastive divergence algorithm.
This pre-training step makes the network avoid an
over-fitting problem of the classical neural networks.
Once the networks are pre-trained, we utilize a back
propagation algorithm with known labels of the activity
training sets to fine tune the recognizer which is later
used for HAR. In order to verify our system, we have
compared the results of proposed methodology with the
HMM based HAR using a database of Microsoft Research
Cambridge-12 (MSRC-12). Our experimental results show
that the proposed approach is able to recognize various
human activities and it outperforms HMMs. We have
achieved the average recognition accuracy of 97.54% for
12 activities. The results are 5.05% more accurate than
that of the HMM based HAR and 60 times faster in
training time. Then we have implemented and tested our
proposed system for real-time HAR. In our real-time
system, we obtain sequential frames of human depth
silhouettes captured by a single depth camera. Then, we
utilize our trained Random Forests (RFs) to recognize
the 31 human body parts from the depth silhouettes. From
the body parts map, we extract a set of activity
features which is a vector of joint angles from the
recognized body parts from 50 sequential depth frames.
Finally, we apply the activity features to the proposed
DBN. We have verified the feasibility of HAR in
real-time.
Keywords: Human Activity
Recognition, Depth Sensor, Deep Learning, Deep Belief
Network, Restricted Boltzmann Machine
Pages:
015-019