Event detection in surveillance videos: a review

Since 2008, a variety of systems have been designed to detect events in security cameras. There are also more than a hundred journal articles and conference papers published in this field. However, no survey has focused on recognizing events in the surveillance system. Thus, motivated us to provide a comprehensive review of the different developed event detection systems. We start our discussion with the pioneering methods that used the TRECVid-SED dataset and then developed methods using VIRAT dataset in TRECVid evaluation. To better understand the designed systems, we describe the components of each method and the modifications of the existing method separately. We have outlined the significant challenges related to untrimmed security video action detection. Suitable metrics are also presented for assessing the performance of the proposed models. Our study indicated that the majority of researchers classified events into two groups on the basis of the number of participants and the duration of the event for the TRECVid-SED Dataset. Depending on the group of events, one or more models to identify all the events were used. For the VIRAT dataset, object detection models to localize the first stage activities were used throughout the work. Except one study, a 3D convolutional neural network (3D-CNN) to extract Spatio-temporal features or classifying different activities were used. From the review that has been carried, it is possible to conclude that developing an automatic surveillance event detection system requires three factors: accurate and fast object detection in the first stage to localize the activities, and classification model to draw some conclusion from the input values.