41 research outputs found
TagBook: A Semantic Video Representation without Supervision for Event Detection
We consider the problem of event detection in video for scenarios where only
few, or even zero examples are available for training. For this challenging
setting, the prevailing solutions in the literature rely on a semantic video
representation obtained from thousands of pre-trained concept detectors.
Different from existing work, we propose a new semantic video representation
that is based on freely available social tagged videos only, without the need
for training any intermediate concept detectors. We introduce a simple
algorithm that propagates tags from a video's nearest neighbors, similar in
spirit to the ones used for image retrieval, but redesign it for video event
detection by including video source set refinement and varying the video tag
assignment. We call our approach TagBook and study its construction,
descriptiveness and detection performance on the TRECVID 2013 and 2014
multimedia event detection datasets and the Columbia Consumer Video dataset.
Despite its simple nature, the proposed TagBook video representation is
remarkably effective for few-example and zero-example event detection, even
outperforming very recent state-of-the-art alternatives building on supervised
representations.Comment: accepted for publication as a regular paper in the IEEE Transactions
on Multimedi
Evaluation of Automatic Video Captioning Using Direct Assessment
We present Direct Assessment, a method for manually assessing the quality of
automatically-generated captions for video. Evaluating the accuracy of video
captions is particularly difficult because for any given video clip there is no
definitive ground truth or correct answer against which to measure. Automatic
metrics for comparing automatic video captions against a manual caption such as
BLEU and METEOR, drawn from techniques used in evaluating machine translation,
were used in the TRECVid video captioning task in 2016 but these are shown to
have weaknesses. The work presented here brings human assessment into the
evaluation by crowdsourcing how well a caption describes a video. We
automatically degrade the quality of some sample captions which are assessed
manually and from this we are able to rate the quality of the human assessors,
a factor we take into account in the evaluation. Using data from the TRECVid
video-to-text task in 2016, we show how our direct assessment method is
replicable and robust and should scale to where there many caption-generation
techniques to be evaluated.Comment: 26 pages, 8 figure
Deep CNN Framework for Audio Event Recognition using Weakly Labeled Web Data
The development of audio event recognition models requires labeled training
data, which are generally hard to obtain. One promising source of recordings of
audio events is the large amount of multimedia data on the web. In particular,
if the audio content analysis must itself be performed on web audio, it is
important to train the recognizers themselves from such data. Training from
these web data, however, poses several challenges, the most important being the
availability of labels : labels, if any, that may be obtained for the data are
generally {\em weak}, and not of the kind conventionally required for training
detectors or classifiers. We propose that learning algorithms that can exploit
weak labels offer an effective method to learn from web data. We then propose a
robust and efficient deep convolutional neural network (CNN) based framework to
learn audio event recognizers from weakly labeled data. The proposed method can
train from and analyze recordings of variable length in an efficient manner and
outperforms a network trained with {\em strongly labeled} web data by a
considerable margin
AudioPairBank: Towards A Large-Scale Tag-Pair-Based Audio Content Analysis
Recently, sound recognition has been used to identify sounds, such as car and
river. However, sounds have nuances that may be better described by
adjective-noun pairs such as slow car, and verb-noun pairs such as flying
insects, which are under explored. Therefore, in this work we investigate the
relation between audio content and both adjective-noun pairs and verb-noun
pairs. Due to the lack of datasets with these kinds of annotations, we
collected and processed the AudioPairBank corpus consisting of a combined total
of 1,123 pairs and over 33,000 audio files. One contribution is the previously
unavailable documentation of the challenges and implications of collecting
audio recordings with these type of labels. A second contribution is to show
the degree of correlation between the audio content and the labels through
sound recognition experiments, which yielded results of 70% accuracy, hence
also providing a performance benchmark. The results and study in this paper
encourage further exploration of the nuances in audio and are meant to
complement similar research performed on images and text in multimedia
analysis.Comment: This paper is a revised version of "AudioSentibank: Large-scale
Semantic Ontology of Acoustic Concepts for Audio Content Analysis