524 research outputs found
Multilevel Language and Vision Integration for Text-to-Clip Retrieval
We address the problem of text-based activity retrieval in video. Given a
sentence describing an activity, our task is to retrieve matching clips from an
untrimmed video. To capture the inherent structures present in both text and
video, we introduce a multilevel model that integrates vision and language
features earlier and more tightly than prior work. First, we inject text
features early on when generating clip proposals, to help eliminate unlikely
clips and thus speed up processing and boost performance. Second, to learn a
fine-grained similarity metric for retrieval, we use visual features to
modulate the processing of query sentences at the word level in a recurrent
neural network. A multi-task loss is also employed by adding query
re-generation as an auxiliary task. Our approach significantly outperforms
prior work on two challenging benchmarks: Charades-STA and ActivityNet
Captions.Comment: AAAI 201
Vision and language understanding with localized evidence
Enabling machines to solve computer vision tasks with natural language components can greatly improve human interaction with computers. In this thesis, we address vision and language tasks with deep learning methods that explicitly localize relevant visual evidence. Spatial evidence localization in images enhances the interpretability of the model, while temporal localization in video is necessary to remove irrelevant content. We apply our methods to various vision and language tasks, including visual question answering, temporal activity detection, dense video captioning and cross-modal retrieval.
First, we tackle the problem of image question answering, which requires the model to predict answers to questions posed about images. We design a memory network with a question-guided spatial attention mechanism which assigns higher weights to regions that are more relevant to the question. The visual evidence used to derive the answer can be shown by visualizing the attention weights in images. We then address the problem of localizing temporal evidence in videos. For most language/vision tasks, only part of the video is relevant to the linguistic component, so we need to detect these relevant events in videos. We propose an end-to-end model for temporal activity detection, which can detect arbitrary length activities by coordinate regression with respect to anchors and contains a proposal stage to filter out background segments, saving computation time. We further extend activity category detection to event captioning, which can express richer semantic meaning compared to a class label. This derives the problem of dense video captioning, which involves two sub-problems: localizing distinct events in long video and generating captions for the localized events. We propose an end-to-end hierarchical captioning model with vision and language context modeling in which the captioning training affects the activity localization. Lastly, the task of text-to-clip video retrieval requires one to localize the specified query instead of detecting and captioning all events. We propose a model based on the early fusion of words and visual features, outperforming standard approaches which embed the whole sentence before performing late feature fusion. Furthermore, we use queries to regulate the proposal network to generate query related proposals.
In conclusion, our proposed visual localization mechanism applies across a variety of vision and language tasks and achieves state-of-the-art results. Together with the inference module, our work can contribute to solving other tasks such as video question answering in future research
Video-Text Modeling with Zero-Shot Transfer from Contrastive Captioners
This work explores an efficient approach to establish a foundational
video-text model for tasks including open-vocabulary video classification,
text-to-video retrieval, video captioning and video question-answering. We
present VideoCoCa that reuses a pretrained image-text contrastive captioner
(CoCa) model and adapt it to video-text tasks with minimal extra training.
While previous works adapt image-text models with various cross-frame fusion
modules (for example, cross-frame attention layer or perceiver resampler) and
finetune the modified architecture on video-text data, we surprisingly find
that the generative attentional pooling and contrastive attentional pooling
layers in the image-text CoCa design are instantly adaptable to ``flattened
frame embeddings'', yielding a strong zero-shot transfer baseline for many
video-text tasks. Specifically, the frozen image encoder of a pretrained
image-text CoCa takes each video frame as inputs and generates token
embeddings per frame for totally video frames. We flatten
token embeddings as a long sequence of frozen video representation and apply
CoCa's generative attentional pooling and contrastive attentional pooling on
top. All model weights including pooling layers are directly loaded from an
image-text CoCa pretrained model. Without any video or video-text data,
VideoCoCa's zero-shot transfer baseline already achieves state-of-the-art
results on zero-shot video classification on Kinetics 400/600/700, UCF101,
HMDB51, and Charades, as well as zero-shot text-to-video retrieval on MSR-VTT
and ActivityNet Captions. We also explore lightweight finetuning on top of
VideoCoCa, and achieve strong results on video question-answering (iVQA,
MSRVTT-QA, MSVD-QA) and video captioning (MSR-VTT, ActivityNet, Youcook2). Our
approach establishes a simple and effective video-text baseline for future
research.Comment: Technical repor
μ΄μΌκΈ°ν μ€λͺ λ¬Έμ νμ©ν λκ·λͺ¨ λΉλμ€ νμ΅ μ°κ΅¬
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Όλ¬Έ (λ°μ¬) -- μμΈλνκ΅ λνμ : 곡과λν μ»΄ν¨ν°κ³΅νλΆ, 2021. 2. κΉκ±΄ν¬.Extensive contributions are being made to develop intelligent agents that can recognize and communicate with the world. In this sense, various video-language tasks have drawn a lot of interests in computer vision research, including image/video captioning, video retrieval and video question answering.
It can be applied to high-level computer vision tasks and various future industries such as search engines, social marketing, automated driving, and robotics support through QA / dialog generation for the surrounding environment.
However, despite these developments, video-language learning suffers from a higher degree of complexity.
This thesis investigates methodologies for learning the relationship between videos and free-formed languages, including explanations, conversations, and question-and-answers, so that the machine can easily adapt to target downstream tasks.
First, we introduce several methods to learn the relationship between long sentences and videos efficiently. We introduce the approaches for supervising human attention transfer for the video attention model, which shows the video attention mechanism can benefit from explicit human gaze labels. Next, we introduce the end-to-end semantic attention method, which further reduces the visual attention algorithm's complexity by using the representative visual concept word detected by the attention-based detector. As a follow-up study on previous methods, we introduce a JSFusion (Joint Sequence Fusion) method that enables efficient video search and QA by enabling many-to-many matching of attention model.
Next, we introduce the CiSIN(Character in Story Identification Network), which uses Attention to increase the performance of character grounding and character re-identification in the movie. Finally, we introduce Transitional Adaptation, which promotes the caption generation models to generates coherent narratives for long videos.
In summary, this thesis presents a novel approaches for automatic video description generation/retrieval and shows the benefits of extracting linguistic knowledge for object and motion in the video as well as the advantage of multimodal audio-visual learning for understanding videos. Since the proposed methods are easily adapted to any video-language tasks, it is expected to be applied to the latest models, bringing additional performance improvements.
Moving forward, we plan to design an unsupervised video learning framework that can solve many challenges in the industry by integrating an unlimited amount of video, audio, and free-formed language data from the web.μκ°-μΈμ΄ νμ΅μ μ΄λ―Έμ§/λΉλμ€ μΊ‘μ
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κ³μ λ§μ λμ λ₯Ό ν΄κ²°ν μ μλ λΉμ§λ νμ΅ λͺ¨λΈμ λ§λ€κ³ μ νλ€.Chapter 1
Introduction
1.1 Contributions . . . . . . . . . . . . . . . . . . . . . . . . . . . . .4
1.2 Outline of the thesis . . . . . . . . . . . . . . . . . . . . . . . . .8
Chapter 2
Related Work
2.1 Video Captioning . . . . . . . . . . . . . . . . . . . . . . . . . . .9
2.2 Video Retrieval with Natural Language . . . . . . . . . . . . . . 12
2.3 Video Question and Answering . . . . . . . . . . . . . . . . . . . 13
2.4 Cross-modal Representation Learning for Vision and LanguageTasks . . . . 15
Chapter 3 Human Attention Transfer for Video Captioning18
3.1 Introduction
3.2 Video Datasets for Caption and Gaze . . . . . . . . . . . . . . . 21
3.3 Approach . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 22
3.3.1 Video Pre-processing and Description . . . . . . . . . . . 22
3.3.2The Recurrent Gaze Prediction (RGP) Model . . . . . . . 23
3.3.3Construction of Visual Feature Pools . . . . . . . . . . . . 24
3.3.4The Decoder for Caption Generation . . . . . . . . . . . . 26
3.3.5Training . . . . . . . . . . . . . . . . . . . . . . . . . . . . 28
3.4 Experiments . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 29
3.4.1Evaluation of Gaze Prediction . . . . . . . . . . . . . . . . 29
3.4.2Evaluation of Video Captioning . . . . . . . . . . . . . . . 32
3.4.3Human Evaluation via AMT . . . . . . . . . . . . . . . . 35
3.5 Conclusion . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 36
Chapter 4 Semantic Word Attention for Video QA and VideoCaptioning
4.1 Introduction . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 37
4.1.1Related Work . . . . . . . . . . . . . . . . . . . . . . . . . 39
4.1.2Contributions . . . . . . . . . . . . . . . . . . . . . . . . . 40
4.2 Approach . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 41
4.2.1Preprocessing . . . . . . . . . . . . . . . . . . . . . . . . . 41
4.2.2An Attention Model for Concept Detection . . . . . . . . 42
4.2.3Video-to-Language Models . . . . . . . . . . . . . . . . . 45
4.2.4A Model for Description . . . . . . . . . . . . . . . . . . . 45
4.2.5A Model for Fill-in-the-Blank . . . . . . . . . . . . . . . . 48
4.2.6A Model for Multiple-Choice Test . . . . . . . . . . . . . 50
4.2.7A Model for Retrieval . . . . . . . . . . . . . . . . . . . . 51
4.3 Experiments . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 52
4.3.1The LSMDC Dataset and Tasks . . . . . . . . . . . . . . 52
4.3.2Quantitative Results . . . . . . . . . . . . . . . . . . . . . 54
4.3.3Qualitative Results . . . . . . . . . . . . . . . . . . . . . . 56
4.4 Conclusion . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 57
Chapter 5 Joint Sequnece Fusion Attention for Multimodal Sequence Data
5.1 Introduction . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 59
5.2 Related Work . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 61
5.3 Approach . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 63
5.3.1Preprocessing . . . . . . . . . . . . . . . . . . . . . . . . . 63
5.3.2The Joint Semantic Tensor . . . . . . . . . . . . . . . . . 65
5.3.3The Convolutional Hierarchical Decoder . . . . . . . . . . 66
5.3.4An Illustrative Example of How the JSFusion Model Works 68
5.3.5Training . . . . . . . . . . . . . . . . . . . . . . . . . . . . 69
5.3.6Implementation of Video-Language Models . . . . . . . . 69
5.4 Experiments . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 71
5.4.1LSMDC Dataset and Tasks . . . . . . . . . . . . . . . . . 71
5.4.2MSR-VTT-(RET/MC) Dataset and Tasks . . . . . . . . . 73
5.4.3Quantitative Results . . . . . . . . . . . . . . . . . . . . . 74
5.4.4Qualitative Results . . . . . . . . . . . . . . . . . . . . . . 76
5.5 Conclusion . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 78
Chapter 6 Character Re-Identification and Character Ground-ing for Movie Understanding
6.1 Introduction . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 79
6.2 Related Work . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 81
6.3 Approach . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 83
6.3.1Video Preprocessing . . . . . . . . . . . . . . . . . . . . . 84
6.3.2Visual Track Embedding . . . . . . . . . . . . . . . . . . . 85
6.3.3Textual Character Embedding . . . . . . . . . . . . . . . 86
6.3.4Character Grounding . . . . . . . . . . . . . . . . . . . . 87
6.3.5Re-Identification . . . . . . . . . . . . . . . . . . . . . . . 88
6.3.6Joint Training . . . . . . . . . . . . . . . . . . . . . . . . 90
6.4 Experiments . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 92
6.4.1Experimental Setup . . . . . . . . . . . . . . . . . . . . . 92
6.4.2Quantitative Results . . . . . . . . . . . . . . . . . . . . . 93
6.4.3Qualitative Results . . . . . . . . . . . . . . . . . . . . . . 95
6.5 Conclusion . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 97
Chapter 7 Transitional Adaptation of Pretrained Models forVisual Storytelling
7.1 Introduction . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 99
7.2 Related Work . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 101
7.3 Approach . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 103
7.3.1The Visual Encoder . . . . . . . . . . . . . . . . . . . . . 104
7.3.2The Language Generator . . . . . . . . . . . . . . . . . . 104
7.3.3Adaptation training . . . . . . . . . . . . . . . . . . . . . 105
7.3.4The Sequential Coherence Loss . . . . . . . . . . . . . . . 105
7.3.5Training with the adaptation Loss . . . . . . . . . . . . . 107
7.3.6Fine-tuning and Inference . . . . . . . . . . . . . . . . . . 107
7.4 Experiments . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 108
7.4.1Experimental Setup . . . . . . . . . . . . . . . . . . . . . 109
7.4.2Quantitative Results . . . . . . . . . . . . . . . . . . . . . 112
7.4.3Further Analyses . . . . . . . . . . . . . . . . . . . . . . . 112
7.4.4Human Evaluation Results . . . . . . . . . . . . . . . . . 115
7.4.5Qualitative Results . . . . . . . . . . . . . . . . . . . . . . 116
7.5 Conclusion . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 116
Chapter 8 Conclusion
8.1 Summary . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 117
8.2 Future Works . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 120
Bibliography ... 123
μμ½ ... 148
Acknowledgements ... 150Docto
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