6,235 research outputs found
Attacking Visual Language Grounding with Adversarial Examples: A Case Study on Neural Image Captioning
Visual language grounding is widely studied in modern neural image captioning
systems, which typically adopts an encoder-decoder framework consisting of two
principal components: a convolutional neural network (CNN) for image feature
extraction and a recurrent neural network (RNN) for language caption
generation. To study the robustness of language grounding to adversarial
perturbations in machine vision and perception, we propose Show-and-Fool, a
novel algorithm for crafting adversarial examples in neural image captioning.
The proposed algorithm provides two evaluation approaches, which check whether
neural image captioning systems can be mislead to output some randomly chosen
captions or keywords. Our extensive experiments show that our algorithm can
successfully craft visually-similar adversarial examples with randomly targeted
captions or keywords, and the adversarial examples can be made highly
transferable to other image captioning systems. Consequently, our approach
leads to new robustness implications of neural image captioning and novel
insights in visual language grounding.Comment: Accepted by 56th Annual Meeting of the Association for Computational
Linguistics (ACL 2018). Hongge Chen and Huan Zhang contribute equally to this
wor
Image Representations and New Domains in Neural Image Captioning
We examine the possibility that recent promising results in automatic caption
generation are due primarily to language models. By varying image
representation quality produced by a convolutional neural network, we find that
a state-of-the-art neural captioning algorithm is able to produce quality
captions even when provided with surprisingly poor image representations. We
replicate this result in a new, fine-grained, transfer learned captioning
domain, consisting of 66K recipe image/title pairs. We also provide some
experiments regarding the appropriateness of datasets for automatic captioning,
and find that having multiple captions per image is beneficial, but not an
absolute requirement.Comment: 11 Pages, 5 Images, To appear at EMNLP 2015's Vision + Learning
worksho
Deep Interactive Region Segmentation and Captioning
With recent innovations in dense image captioning, it is now possible to
describe every object of the scene with a caption while objects are determined
by bounding boxes. However, interpretation of such an output is not trivial due
to the existence of many overlapping bounding boxes. Furthermore, in current
captioning frameworks, the user is not able to involve personal preferences to
exclude out of interest areas. In this paper, we propose a novel hybrid deep
learning architecture for interactive region segmentation and captioning where
the user is able to specify an arbitrary region of the image that should be
processed. To this end, a dedicated Fully Convolutional Network (FCN) named
Lyncean FCN (LFCN) is trained using our special training data to isolate the
User Intention Region (UIR) as the output of an efficient segmentation. In
parallel, a dense image captioning model is utilized to provide a wide variety
of captions for that region. Then, the UIR will be explained with the caption
of the best match bounding box. To the best of our knowledge, this is the first
work that provides such a comprehensive output. Our experiments show the
superiority of the proposed approach over state-of-the-art interactive
segmentation methods on several well-known datasets. In addition, replacement
of the bounding boxes with the result of the interactive segmentation leads to
a better understanding of the dense image captioning output as well as accuracy
enhancement for the object detection in terms of Intersection over Union (IoU).Comment: 17, pages, 9 figure
Temporal Deformable Convolutional Encoder-Decoder Networks for Video Captioning
It is well believed that video captioning is a fundamental but challenging
task in both computer vision and artificial intelligence fields. The prevalent
approach is to map an input video to a variable-length output sentence in a
sequence to sequence manner via Recurrent Neural Network (RNN). Nevertheless,
the training of RNN still suffers to some degree from vanishing/exploding
gradient problem, making the optimization difficult. Moreover, the inherently
recurrent dependency in RNN prevents parallelization within a sequence during
training and therefore limits the computations. In this paper, we present a
novel design --- Temporal Deformable Convolutional Encoder-Decoder Networks
(dubbed as TDConvED) that fully employ convolutions in both encoder and decoder
networks for video captioning. Technically, we exploit convolutional block
structures that compute intermediate states of a fixed number of inputs and
stack several blocks to capture long-term relationships. The structure in
encoder is further equipped with temporal deformable convolution to enable
free-form deformation of temporal sampling. Our model also capitalizes on
temporal attention mechanism for sentence generation. Extensive experiments are
conducted on both MSVD and MSR-VTT video captioning datasets, and superior
results are reported when comparing to conventional RNN-based encoder-decoder
techniques. More remarkably, TDConvED increases CIDEr-D performance from 58.8%
to 67.2% on MSVD.Comment: AAAI 201
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