Title
Learning a discriminative mid-level feature for action recognition.
Abstract
In this paper, we address the problem of recognizing human actions from videos. Most of the existing approaches employ low-level features (e.g., local features and global features) to represent an action video. However, algorithms based on low-level features are not robust to complex environments such as cluttered background, camera movement and illumination change. Therefore, we propose a novel random forest learning framework to construct a discriminative and informative mid-level feature from low-level features of densely sampled 3D cuboids. Each cuboid is classified by the corresponding random forests with a novel fusion scheme, and the cuboid’s posterior probabilities of all categories are normalized to generate a histogram. After that, we obtain our mid-level feature by concatenating histograms of all the cuboids. Since a single low-level feature is not enough to capture the variations of human actions, multiple complementary low-level features (i.e., optical flow and histogram of gradient 3D features) are employed to describe 3D cuboids. Moreover, temporal context between local cuboids is exploited as another type of low-level feature. The above three low-level features (i.e., optical flow, histogram of gradient 3D features and temporal context) are effectively fused in the proposed learning framework. Finally, the mid-level feature is employed by a random forest classifier for robust action recognition. Experiments on the Weizmann, UCF sports, Ballet, and multi-view IXMAS datasets demonstrate that out mid-level feature learned from multiple low-level features can achieve a superior performance over state-of-the-art methods.
Year
DOI
Venue
2014
10.1007/s11432-013-4938-y
SCIENCE CHINA Information Sciences
Keywords
Field
DocType
action recognition, mid-level feature, feature fusion, temporal context
Histogram,Computer vision,Feature vector,Pattern recognition,Feature (computer vision),Feature extraction,Feature (machine learning),Artificial intelligence,Random forest,Optical flow,Discriminative model,Mathematics
Journal
Volume
Issue
ISSN
57
5
1869-1919
Citations 
PageRank 
References 
15
0.40
30
Authors
5
Name
Order
Citations
PageRank
Cuiwei Liu1543.04
Mingtao Pei224626.35
Xinxiao Wu327220.21
Yu Kong441224.72
Yunde Jia595884.33