A Neural Network for Image Anomaly Detection with Deep Pyramidal Representations and Dynamic Routing

Image anomaly detection is an application-driven problem where the aim is to identify novel samples, which differ significantly from the normal ones. We here propose Pyramidal Image Anomaly DEtector (PIADE), a deep reconstruction-based pyramidal approach, in which image features are extracted at different scale levels to better catch the peculiarities that could help to discriminate between normal and anomalous data. The features are dynamically routed to a reconstruction layer and anomalies can be identified by comparing the input image with its reconstruction. Unlike similar approaches, the comparison is done by using structural similarity and perceptual loss rather than trivial pixel-by-pixel comparison. The proposed method performed at par or better than the state-of-the-art methods when tested on publicly available datasets such as CIFAR10, COIL-100 and MVTec

Dynamic instance generation for few-shot handwritten document layout segmentation (short paper)

Historical handwritten document analysis is an important activity to retrieve information about our past. Given that this type of process is slow and time-consuming, the humanities community is searching for new techniques that could aid them in this activity. Document layout analysis is a branch of machine learning that aims to extract semantic informations from digitised documents. Here we propose a new framework for handwritten document layout analysis that differentiates from the current state-of-the-art by the fact that it features few-shot learning, thus allowing for good results with little manually labelled data and the dynamic instance generation process. Our results were obtained using the DIVA - HisDB dataset

"Forget" the Forget Gate: Estimating Anomalies in Videos using Self-contained Long Short-Term Memory Networks

Abnormal event detection is a challenging task that requires effectively handling intricate features of appearance and motion. In this paper, we present an approach of detecting anomalies in videos by learning a novel LSTM based self-contained network on normal dense optical flow. Due to their sigmoid implementations, standard LSTM's forget gate is susceptible to overlooking and dismissing relevant content in long sequence tasks like abnormality detection. The forget gate mitigates participation of previous hidden state for computation of cell state prioritizing current input. In addition, the hyperbolic tangent activation of standard LSTMs sacrifices performance when a network gets deeper. To tackle these two limitations, we introduce a bi-gated, light LSTM cell by discarding the forget gate and introducing sigmoid activation. Specifically, the LSTM architecture we come up with fully sustains content from previous hidden state thereby enabling the trained model to be robust and make context-independent decision during evaluation. Removing the forget gate results in a simplified and undemanding LSTM cell with improved performance effectiveness and computational efficiency. Empirical evaluations show that the proposed bi-gated LSTM based network outperforms various LSTM based models verifying its effectiveness for abnormality detection and generalization tasks on CUHK Avenue and UCSD datasets.Comment: 16 pages, 7 figures, Computer Graphics International (CGI) 202

Unsupervised Activity Extraction on Long-Term Video Recordings employing Soft Computing Relations

International audienceIn this work we present a novel approach for activity extraction and knowledge discovery from video employing fuzzy relations. Spatial and temporal properties from detected mobile objects are modeled with fuzzy relations. These can then be aggregated employing typical soft-computing algebra. A clustering algorithm based on the transitive closure calculation of the fuzzy relations allows finding spatio-temporal patterns of activity. We present results obtained on videos corresponding to different sequences of apron monitoring in the Toulouse airport in France

Anomalous trajectory detection using support vector machines

One of the most promising approaches to event analysis in video sequences is based on the automatic modelling of common patterns of activity for later detection of anomalous events. This approach is especially useful in those applications that do not necessarily require the exact identification of the events, but need only the detection of anomalies that should be reported to a human operator (e.g. video surveillance or traffic monitoring applications). In this paper we propose a trajectory analysis method based on Support Vector Machines; the SVM model is trained on a given set of trajectories and can subsequently detect trajectories substantially differing from the training ones. Particular emphasis is placed on a novel method for estimating the parameter v, since it heavily influences the performances of the system but cannot be easily estimated apriori. Experimental results are given both on synthetic and real-world dat

Surveillance-Oriented Event Detection in Video Streams

The field of computer vision covers a large number of research topics, ranging from low-level processing aspects up to high-level image and video interpretation problems. This article gives a short introduction to security-oriented event analysis systems, whose aim is to give a semantic interpretation to video sequences in order to detect anomalous, dangerous or forbidden situations. The two main approaches to event analysis are here described, highlighting their advantages and limits. For each approach, a practical example is given, showing how events can be explicitly recognized in terms of their structure, or alternatively how they can be classified according to their degree of anomaly

PTZ network configuration for optimal 3D coverage

2nonenonePiciarelli C; Foresti GLPiciarelli, Claudio; Foresti, Gian Luc