Anomaly Detection and Activity Perception Using Covariance Descriptor for Trajectories

2016-10-16
In this work, we study the problems of anomaly detection and activity perception through the trajectories of objects in crowded scenes. For this purpose, we propose a novel representation for trajectories via covariance features. Representing trajectories via feature covariance matrices enables us to calculate the distance between the trajectories of different lengths. After setting this proposed representation and calculation of distances between trajectories, anomaly detection is achieved by sparse representations on nearest neighbors and activity perception is achieved by extracting the dominant motion patterns in the scene through the use of spectral clustering. Conducted experiments show that the proposed method yields results which are outperforming or comparable with state of the art.

Suggestions

Anomaly Detection in Trajectories
Ergezer, Hamza; Leblebicioğlu, Mehmet Kemal (2016-05-19)
In this work, we study the problem of anomaly detection of the trajectories of objects in a visual scene. For this purpose, we propose a novel representation for trajectories utilizing covariance features. Representing trajectories via covariance features enables us to calculate the distance between the trajectories of different lengths. After setting this proposed representation and calculation of distances, anomaly detection is achieved by sparse representations on nearest neighbours. Conducted experiment...
Visual object representations: effects of feature frequency and similarity
Eren Kanat, Selda; Hohenberger, Annette Edeltraud; Department of Cognitive Sciences (2011)
The effects of feature frequency and similarity on object recognition have been examined through behavioral experiments, and a model of the formation of visual object representations and old/new recognition has been proposed. A number of experiments were conducted to test the hypothesis that frequency and similarity of object features affect the old/new responses to test stimuli in a later recognition task. In the first experiment, when the feature frequencies are controlled, there was a significant increas...
Object detection through search with a foveated visual system
Akbaş, Emre (2017-10-01)
Humans and many other species sense visual information with varying spatial resolution across the visual field (foveated vision) and deploy eye movements to actively sample regions of interests in scenes. The advantage of such varying resolution architecture is a reduced computational, hence metabolic cost. But what are the performance costs of such processing strategy relative to a scheme that processes the visual field at high spatial resolution? Here we first focus on visual search and combine object det...
Abnormal Crowd Behavior Detection Using Novel Optical Flow-Based Features
Direkoglu, Cem; Sah, Melike; O'Connor, Noel E. (2017-09-01)
In this paper, we propose a novel optical flow based features for abnormal crowd behaviour detection. The proposed feature is mainly based on the angle difference computed between the optical flow vectors in the current frame and in the previous frame at each pixel location. The angle difference information is also combined with the optical flow magnitude to produce new, effective and direction invariant event features. A one-class SVM is utilized to learn normal crowd behavior. If a test sample deviates si...
Parameter extraction and image enhancement for catadioptric omnidirectional cameras
Baştanlar, Yalın; Çetin, Yasemin; Department of Information Systems (2005)
In this thesis, catadioptric omnidirectional imaging systems are analyzed in detail. Omnidirectional image (ODI) formation characteristics of different camera-mirror configurations are examined and geometrical relations for panoramic and perspective image generation with common mirror types are summarized. A method is developed to determine the unknown parameters of a hyperboloidal-mirrored system using the world coordinates of a set of points and their corresponding image points on the ODI. A linear relati...
Citation Formats
H. Ergezer and M. K. Leblebicioğlu, “Anomaly Detection and Activity Perception Using Covariance Descriptor for Trajectories,” 2016, vol. 9914, Accessed: 00, 2020. [Online]. Available: https://hdl.handle.net/11511/39144.