Trajectory-based anomalous behaviour
detection for intelligent traffic surveillance
ISSN 1751-956X
Received on 18th September 2014
Revised on 4th February 2015
Accepted on 21st February 2015
doi: 10.1049/iet-its.2014.0238
www.ietdl.org
Yingfeng Cai
1
, Hai Wang
2
✉
, Xiaobo Chen
1
, Haobin Jiang
2
1
Automotive Engineering Research Institute, Jiangsu University, Zhenjiang 212013, People’s Republic of China
2
School of Automotive and Traffic Engineering, Jiangsu University, Zhenjiang 212013, People’s Republic of China
✉ E-mail: wanghai1019@163.com
Abstract: This study proposes an efficient anomalous behaviour detection framework using trajectory analysis. Such
framework includes the trajectory pattern learning module and the online abnormal detection module. In the pattern
learning module, a coarse-to-fine clustering strategy is utilised. Vehicle trajectories are coarsely grouped into coherent
clusters according to the main flow direction (MFD) vectors followed by a three-stage filtering algorithm. Then a robust
K-means clustering algorithm is used in each c oarse cluster to get fine cl assification by which the outliers are
distinguished. Finally, the hidden Markov model (HMM) is used to establish the path pattern within eac h cluster. In the
online detection module, the new vehicle trajectory is compared against a ll the MFD distributions and the HMMs so
that the coherence with common motion patterns can be evaluated. Besides t hat, a real-time abnormal detection
method is proposed . The abnormal behaviour can be d etected when happening. Experimental results illustrate that the
detection rate of the proposed algorithm is close to t he state-of-the-art abnormal event detection systems. In addition,
the proposed system provides the lowest false detection rate among selected methods. It i s suitable for in telligent
surveillance applications.
1 Introduction
Intelligent visual surveillance is an important facet of machine vision
research. One of the most important goals of visual surveillance
systems is to track objects and further analyse their behaviours in
order to detect anomalies or predict potential anomalous
behaviours before occur [1, 2]. In traffic applications, the detection
of vehicle anomalous behaviours (such as wrong turn and illegal
parking), which can improve the road safety, is one main concern
of accident management department [3–5]. Nowadays, the
increasing number of cameras generates large amounts of video
data, making it infeasible for a human to accurately process.
Behaviour analysis systems can be employed to filter out relevant
data, focusing attention where it is needed most. By these reasons,
behaviour analysis research in the field of intelligent transportation
systems became very significant.
In most cases, vehicles in the traffic scene do not move randomly.
Instead, they usually follow specific motion patterns. So the
anomalous behaviours can be detected based on the learning of
normal trajectory patterns [6–8]. The general overview of the
trajectory-based abnormality detection system is given in Fig. 1.
The system is divided into two modules.
In the first module, trajectories captured from video sources are
filtered to remove the noise caused by wrong tracking. Then
trajectories are clustered to determine the common route models,
where clustering serves as a pre-processing step for further
modelling. By modelling of the common routes, normal vehicle
behaviours can be obtained.
In the second module, the new trajectories are extracted by vehicle
detection and tracking. Those that do not belong to any normal route,
can then be considered as anomalies.
1.1 Related work
The key tasks of trajectory analysis include trajectory clustering and
modelling. Jung et al. [3] proposed a method for event detection
based on trajectory clustering. In the training period, captured
trajectories were grouped into coherent clusters for which
four-dimensional (4D) motion histograms were built. In the test
period, each new trajectory was compared with the 4D histograms
of all the clusters. Piciarelli et al. [9] proposed a support vector
machine (SVM)-based anomalous event detection method. They
pointed out that the outliers in the training samples were the
anomalous events. On the basis of that, the trajectories were
clustered with a single-class SVM and the outliers were detected
by the geometric considerations in SVM feature space. Morris and
Trivedi [10] proposed a three-stage hierarchical framework for
unsupervised visual scene description and live analysis. Such
framework indicated important image points, connects them
through spatial routes, and probabilistically modelled
spatio-temporal dynamics with a hidden Markov model (HMM).
Once these path definitions were established, abnormal trajectories
were detected and future intent was predicted. A survey about
vision-based trajectory learning was also done by Morris and
Trivedi [11]. It presented common learning techniques in the
literature to extract automated scene modelling, automated activity
analysis and object interactions. Karavasilis et al. [12] presented a
model-based clustering method by trajectories’ Harris corners.
Clustering is achieved through a sparse regression mixture model
that embodies efficient characteristics in order to handle
trajectories of variable length, and to be translated in measurement
space. Hu et al. [13] used a hierarchic clustering method based on
spatial and temporal information of trajectories. In the work, each
motion pattern is represented with a chain of Gaussian
distributions. On the basis of the learned statistical motion
patterns, statistical methods are used to detect anomalies and
predict behaviours. Besides that, Hu et al. [14] also proposed a
Dirichlet process mixture model (DPMM) for trajectory clustering
and modelling. Each cluster of trajectories was learned by a
time-sensitive DPMM, and then, a parameterised index is
constructed for each cluster. Makris and Ellis [15] proposed a
method for labelling the scene with topological information, which
is then used within a Bayesian approach to detect anomalous
trajectories. Moreover, Bashir et al. [16], Hanwell and Mirmehdi
[17], Cohen et al. [18], Li et al. [19], Singha et al. [20] also made
IET Intelligent Transport Systems
Research Article
IET Intell. Transp. Syst., 2015, Vol. 9, Iss. 8, pp. 810–816
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