7,307 research outputs found
Learning to Detect Violent Videos using Convolutional Long Short-Term Memory
Developing a technique for the automatic analysis of surveillance videos in
order to identify the presence of violence is of broad interest. In this work,
we propose a deep neural network for the purpose of recognizing violent videos.
A convolutional neural network is used to extract frame level features from a
video. The frame level features are then aggregated using a variant of the long
short term memory that uses convolutional gates. The convolutional neural
network along with the convolutional long short term memory is capable of
capturing localized spatio-temporal features which enables the analysis of
local motion taking place in the video. We also propose to use adjacent frame
differences as the input to the model thereby forcing it to encode the changes
occurring in the video. The performance of the proposed feature extraction
pipeline is evaluated on three standard benchmark datasets in terms of
recognition accuracy. Comparison of the results obtained with the state of the
art techniques revealed the promising capability of the proposed method in
recognizing violent videos.Comment: Accepted in International Conference on Advanced Video and Signal
based Surveillance(AVSS 2017
Convolutional Drift Networks for Video Classification
Analyzing spatio-temporal data like video is a challenging task that requires
processing visual and temporal information effectively. Convolutional Neural
Networks have shown promise as baseline fixed feature extractors through
transfer learning, a technique that helps minimize the training cost on visual
information. Temporal information is often handled using hand-crafted features
or Recurrent Neural Networks, but this can be overly specific or prohibitively
complex. Building a fully trainable system that can efficiently analyze
spatio-temporal data without hand-crafted features or complex training is an
open challenge. We present a new neural network architecture to address this
challenge, the Convolutional Drift Network (CDN). Our CDN architecture combines
the visual feature extraction power of deep Convolutional Neural Networks with
the intrinsically efficient temporal processing provided by Reservoir
Computing. In this introductory paper on the CDN, we provide a very simple
baseline implementation tested on two egocentric (first-person) video activity
datasets.We achieve video-level activity classification results on-par with
state-of-the art methods. Notably, performance on this complex spatio-temporal
task was produced by only training a single feed-forward layer in the CDN.Comment: Published in IEEE Rebooting Computin
Flow-Guided Feature Aggregation for Video Object Detection
Extending state-of-the-art object detectors from image to video is
challenging. The accuracy of detection suffers from degenerated object
appearances in videos, e.g., motion blur, video defocus, rare poses, etc.
Existing work attempts to exploit temporal information on box level, but such
methods are not trained end-to-end. We present flow-guided feature aggregation,
an accurate and end-to-end learning framework for video object detection. It
leverages temporal coherence on feature level instead. It improves the
per-frame features by aggregation of nearby features along the motion paths,
and thus improves the video recognition accuracy. Our method significantly
improves upon strong single-frame baselines in ImageNet VID, especially for
more challenging fast moving objects. Our framework is principled, and on par
with the best engineered systems winning the ImageNet VID challenges 2016,
without additional bells-and-whistles. The proposed method, together with Deep
Feature Flow, powered the winning entry of ImageNet VID challenges 2017. The
code is available at
https://github.com/msracver/Flow-Guided-Feature-Aggregation
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