859 research outputs found
Contextual anomaly detection in crowded surveillance scenes
AbstractThis work addresses the problem of detecting human behavioural anomalies in crowded surveillance environments. We focus in particular on the problem of detecting subtle anomalies in a behaviourally heterogeneous surveillance scene. To reach this goal we implement a novel unsupervised context-aware process. We propose and evaluate a method of utilising social context and scene context to improve behaviour analysis. We find that in a crowded scene the application of Mutual Information based social context permits the ability to prevent self-justifying groups and propagate anomalies in a social network, granting a greater anomaly detection capability. Scene context uniformly improves the detection of anomalies in both datasets. The strength of our contextual features is demonstrated by the detection of subtly abnormal behaviours, which otherwise remain indistinguishable from normal behaviour
Abnormal Event Detection in Videos using Spatiotemporal Autoencoder
We present an efficient method for detecting anomalies in videos. Recent
applications of convolutional neural networks have shown promises of
convolutional layers for object detection and recognition, especially in
images. However, convolutional neural networks are supervised and require
labels as learning signals. We propose a spatiotemporal architecture for
anomaly detection in videos including crowded scenes. Our architecture includes
two main components, one for spatial feature representation, and one for
learning the temporal evolution of the spatial features. Experimental results
on Avenue, Subway and UCSD benchmarks confirm that the detection accuracy of
our method is comparable to state-of-the-art methods at a considerable speed of
up to 140 fps
Learning Behavioural Context
The original publication is available at www.springerlink.co
Visual Crowd Analysis: Open Research Problems
Over the last decade, there has been a remarkable surge in interest in
automated crowd monitoring within the computer vision community. Modern
deep-learning approaches have made it possible to develop fully-automated
vision-based crowd-monitoring applications. However, despite the magnitude of
the issue at hand, the significant technological advancements, and the
consistent interest of the research community, there are still numerous
challenges that need to be overcome. In this article, we delve into six major
areas of visual crowd analysis, emphasizing the key developments in each of
these areas. We outline the crucial unresolved issues that must be tackled in
future works, in order to ensure that the field of automated crowd monitoring
continues to progress and thrive. Several surveys related to this topic have
been conducted in the past. Nonetheless, this article thoroughly examines and
presents a more intuitive categorization of works, while also depicting the
latest breakthroughs within the field, incorporating more recent studies
carried out within the last few years in a concise manner. By carefully
choosing prominent works with significant contributions in terms of novelty or
performance gains, this paper presents a more comprehensive exposition of
advancements in the current state-of-the-art.Comment: Accepted in AI Magazine published by Wiley Periodicals LLC on behalf
of the Association for the Advancement of Artificial Intelligenc
Automatic human behaviour anomaly detection in surveillance video
This thesis work focusses upon developing the capability to automatically evaluate
and detect anomalies in human behaviour from surveillance video. We work with
static monocular cameras in crowded urban surveillance scenarios, particularly air-
ports and commercial shopping areas. Typically a person is 100 to 200 pixels high
in a scene ranging from 10 - 20 meters width and depth, populated by 5 to 40 peo-
ple at any given time. Our procedure evaluates human behaviour unobtrusively to
determine outlying behavioural events,
agging abnormal events to the operator.
In order to achieve automatic human behaviour anomaly detection we address
the challenge of interpreting behaviour within the context of the social and physical
environment. We develop and evaluate a process for measuring social connectivity
between individuals in a scene using motion and visual attention features. To do this
we use mutual information and Euclidean distance to build a social similarity matrix
which encodes the social connection strength between any two individuals. We de-
velop a second contextual basis which acts by segmenting a surveillance environment
into behaviourally homogeneous subregions which represent high tra c slow regions
and queuing areas. We model the heterogeneous scene in homogeneous subgroups
using both contextual elements. We bring the social contextual information, the
scene context, the motion, and visual attention features together to demonstrate
a novel human behaviour anomaly detection process which nds outlier behaviour
from a short sequence of video. The method, Nearest Neighbour Ranked Outlier
Clusters (NN-RCO), is based upon modelling behaviour as a time independent se-
quence of behaviour events, can be trained in advance or set upon a single sequence.
We nd that in a crowded scene the application of Mutual Information-based social
context permits the ability to prevent self-justifying groups and propagate anomalies
in a social network, granting a greater anomaly detection capability. Scene context
uniformly improves the detection of anomalies in all the datasets we test upon.
We additionally demonstrate that our work is applicable to other data domains.
We demonstrate upon the Automatic Identi cation Signal data in the maritime
domain. Our work is capable of identifying abnormal shipping behaviour using joint
motion dependency as analogous for social connectivity, and similarly segmenting
the shipping environment into homogeneous regions
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