pwc-archive/papers-with-abstracts huggingface dataset:
Evade Deep Image Retrieval by Stashing Private Images in the Hash Space
Authors: Yanru Xiao,  Cong Wang,  Xing Gao
Date: 2020-06-01 00:00:00
Proceeding: CVPR 2020 6
Tasks: Image Retrieval, Retrieval

With the rapid growth of visual content, deep learning to hash is gaining popularity in the image retrieval community recently. Although it greatly facilitates search efficiency, privacy is also at risks when images on the web are retrieved at a large scale and exploited as a rich mine of personal information. An adversary can extract private images by querying similar images from the targeted category for any usable model. Existing methods based on image processing preserve privacy at a sacrifice of perceptual quality. In this paper, we propose a new mechanism based on adversarial examples to "stash" private images in the deep hash space while maintaining perceptual similarity. We first find that a simple approach of hamming distance maximization is not robust against brute-force adversaries. Then we develop a new loss function by maximizing the hamming distance to not only the original category, but also the centers from all the classes, partitioned into clusters of various sizes. The extensive experiment shows that the proposed defense can harden the attacker's efforts by 2-7 orders of magnitude, without significant increase of computational overhead and perceptual degradation. We also demonstrate 30-60% transferability in hash space with a black-box setting. The code is available at: https://github.com/sugarruy/hashstash
Advisable Learning for Self-Driving Vehicles by Internalizing Observation-to-Action Rules
Authors: Jinkyu Kim,  Suhong Moon,  Anna Rohrbach,  Trevor Darrell,  John Canny
Date: 2020-06-01 00:00:00
Proceeding: CVPR 2020 6
Tasks: Explanation Generation, Semantic Segmentation

Humans learn to drive through both practice and theory, e.g. by studying the rules, while most self-driving systems are limited to the former. Being able to incorporate human knowledge of typical causal driving behaviour should benefit autonomous systems. We propose a new approach that learns vehicle control with the help of human advice. Specifically, our system learns to summarize its visual observations in natural language, predict an appropriate action response (e.g. "I see a pedestrian crossing, so I stop"), and predict the controls, accordingly. Moreover, to enhance interpretability of our system, we introduce a fine-grained attention mechanism which relies on semantic segmentation and object-centric RoI pooling. We show that our approach of training the autonomous system with human advice, grounded in a rich semantic representation, matches or outperforms prior work in terms of control prediction and explanation generation. Our approach also results in more interpretable visual explanations by visualizing object-centric attention maps. Code is available at https://github.com/JinkyuKimUCB/advisable-driving.
ProAlignNet: Unsupervised Learning for Progressively Aligning Noisy Contours
Authors: VSR Veeravasarapu,  Abhishek Goel,  Deepak Mittal,  Maneesh Singh
Date: 2020-06-01 00:00:00
Proceeding: CVPR 2020 6

Contour shape alignment is a fundamental but challenging problem in computer vision, especially when the observations are partial, noisy, and largely misaligned. Recent ConvNet-based architectures that were proposed to align image structures tend to fail with contour representation of shapes, mostly due to the use of proximity-insensitive pixel-wise similarity measures as loss functions in their training processes. This work presents a novel ConvNet, "ProAlignNet," that accounts for large scale misalignments and complex transformations between the contour shapes. It infers the warp parameters in a multi-scale fashion with progressively increasing complex transformations over increasing scales. It learns --without supervision-- to align contours, agnostic to noise and missing parts, by training with a novel loss function which is derived an upperbound of a proximity-sensitive and local shape-dependent similarity metric that uses classical Morphological Chamfer Distance Transform. We evaluate the reliability of these proposals on a simulated MNIST noisy contours dataset via some basic sanity check experiments. Next, we demonstrate the effectiveness of the proposed models in two real-world applications of (i) aligning geo-parcel data to aerial image maps and (ii) refining coarsely annotated segmentation labels. In both applications, the proposed models consistently perform superior to state-of-the-art methods.
Weakly Supervised Fine-Grained Image Classification via Guassian Mixture Model Oriented Discriminative Learning
Authors: Zhihui Wang,  Shijie Wang,  Shuhui Yang,  Haojie Li,  Jianjun Li,  Zezhou Li
Date: 2020-06-01 00:00:00
Proceeding: CVPR 2020 6
Tasks: Fine-Grained Image Classification, Fine-Grained Image Recognition, General Classification, image-classification, Image Classification

Existing weakly supervised fine-grained image recognition (WFGIR) methods usually pick out the discriminative regions from the high-level feature maps directly. We discover that due to the operation of stacking local receptive filed, Convolutional Neural Network causes the discriminative region diffusion in high-level feature maps, which leads to inaccurate discriminative region localization. In this paper, we propose an end-to-end Discriminative Feature-oriented Gaussian Mixture Model (DF-GMM), to address the problem of discriminative region diffusion and find better fine-grained details. Specifically, DF-GMM consists of 1) a low-rank representation mechanism (LRM), which learns a set of low-rank discriminative bases by Gaussian Mixture Model (GMM) in high-level semantic feature maps to improve discriminative ability of feature representation, 2) a low-rank representation reorganization mechanism (LR ^2 M) which resumes the space information corresponding to low-rank discriminative bases to reconstruct the low-rank feature maps. It alleviates the discriminative region diffusion problem and locate discriminative regions more precisely. Extensive experiments verify that DF-GMM yields the best performance under the same settings with the most competitive approaches, in CUB-Bird, Stanford-Cars datasets, and FGVC Aircraft.
Learning User Representations for Open Vocabulary Image Hashtag Prediction
Authors: Thibaut Durand
Date: 2020-06-01 00:00:00
Proceeding: CVPR 2020 6
Tasks: Prediction, Retrieval

In this paper, we introduce an open vocabulary model for image hashtag prediction - the task of mapping an image to its accompanying hashtags. Recent work shows that to build an accurate hashtag prediction model, it is necessary to model the user because of the self-expression problem, in which similar image content may be labeled with different tags. To take into account the user behaviour, we propose a new model that extracts a representation of a user based on his/her image history. Our model allows to improve a user representation with new images or add a new user without retraining the model. Because new hashtags appear all the time on social networks, we design an open vocabulary model which can deal with new hashtags without retraining the model. Our model learns a cross-modal embedding between user conditional visual representations and hashtag word representations. Experiments on a subset of the YFCC100M dataset demonstrate the efficacy of our user representation in user conditional hashtag prediction and user retrieval. We further validate the open vocabulary prediction ability of our model.
Sketch Less for More: On-the-Fly Fine-Grained Sketch-Based Image Retrieval
Authors: Ayan Kumar Bhunia,  Yongxin Yang,  Timothy M. Hospedales,  Tao Xiang,  Yi-Zhe Song
Date: 2020-06-01 00:00:00
Proceeding: CVPR 2020 6
Tasks: Cross-Modal Retrieval, Image Retrieval, On-the-Fly Sketch Based Image Retrieval, Retrieval, Sketch-Based Image Retrieval

Fine-grained sketch-based image retrieval (FG-SBIR) addresses the problem of retrieving a particular photo instance given a user's query sketch. Its widespread applicability is however hindered by the fact that drawing a sketch takes time, and most people struggle to draw a complete and faithful sketch. In this paper, we reformulate the conventional FG-SBIR framework to tackle these challenges, with the ultimate goal of retrieving the target photo with the least number of strokes possible. We further propose an on-the-fly design that starts retrieving as soon as the user starts drawing. To accomplish this, we devise a reinforcement learning based cross-modal retrieval framework that directly optimizes rank of the ground-truth photo over a complete sketch drawing episode. Additionally, we introduce a novel reward scheme that circumvents the problems related to irrelevant sketch strokes, and thus provides us with a more consistent rank list during the retrieval. We achieve superior early-retrieval efficiency over state-of-the-art methods and alternative baselines on two publicly available fine-grained sketch retrieval datasets.
Few-Shot Pill Recognition
Authors: Suiyi Ling,  Andreas Pastor,  Jing Li,  Zhaohui Che,  Junle Wang,  Jieun Kim,  Patrick Le Callet
Date: 2020-06-01 00:00:00
Proceeding: CVPR 2020 6
Tasks: Few-Shot Learning

Pill image recognition is vital for many personal/public health-care applications and should be robust to diverse unconstrained real-world conditions. Most existing pill recognition models are limited in tackling this challenging few-shot learning problem due to the insufficient instances per category. With limited training data, neural network-based models have limitations in discovering most discriminating features, or going deeper. Especially, existing models fail to handle the hard samples taken under less controlled imaging conditions. In this study, a new pill image database, namely CURE, is first developed with more varied imaging conditions and instances for each pill category. Secondly, a W2-net is proposed for better pill segmentation. Thirdly, a Multi-Stream (MS) deep network that captures task-related features along with a novel two-stage training methodology are proposed. Within the proposed framework, a Batch All strategy that considers all the samples is first employed for the sub-streams, and then a Batch Hard strategy that considers only the hard samples mined in the first stage is utilized for the fusion network. By doing so, complex samples that could not be represented by one type of feature could be focused and the model could be forced to exploit other domain-related information more effectively. Experiment results show that the proposed model outperforms state-of-the-art models on both the National Institute of Health (NIH) and our CURE database.
Learning Temporal Co-Attention Models for Unsupervised Video Action Localization
Authors: Guoqiang Gong,  Xinghan Wang,  Yadong Mu,  Qi Tian
Date: 2020-06-01 00:00:00
Proceeding: CVPR 2020 6
Tasks: Action Localization, Clustering, Temporal Action Localization, Triplet

Temporal action localization (TAL) in untrimmed videos recently receives tremendous research enthusiasm. To our best knowledge, this is the first attempt in the literature to explore this task under an unsupervised setting, hereafter referred to as action co-localization (ACL), where only the total count of unique actions that appear in the video set is known. To solve ACL, we propose a two-step "clustering + localization" iterative procedure. The clustering step provides noisy pseudo-labels for the localization step, and the localization step provides temporal co-attention models that in turn improve the clustering performance. Using such two-step procedure, weakly-supervised TAL can be regarded as a direct extension of our ACL model. Technically, our contributions are two-folds: 1) temporal co-attention models, either class-specific or class-agnostic, learned from video-level labels or pseudo-labels in an iterative reinforced fashion; 2) new losses specially designed for ACL, including action-background separation loss and cluster-based triplet loss. Comprehensive evaluations are conducted on 20-action THUMOS14 and 100-action ActivityNet-1.2. On both benchmarks, the proposed model for ACL exhibits strong performances, even surprisingly comparable with state-of-the-art weakly-supervised methods. For example, previous best weakly-supervised model achieves 26.8% under mAP@0.5 on THUMOS14, our new records are 30.1% (weakly-supervised) and 25.0% (unsupervised).
Learning to Measure the Static Friction Coefficient in Cloth Contact
Authors: Abdullah Haroon Rasheed,  Victor Romero,  Florence Bertails-Descoubes,  Stefanie Wuhrer,  Jean-Sebastien Franco,  Arnaud Lazarus
Date: 2020-06-01 00:00:00
Proceeding: CVPR 2020 6
Tasks: Friction

Measuring friction coefficients between cloth and an external body is a longstanding issue in mechanical engineering, never yet addressed with a pure vision-based system. The latter offers the prospect of simpler, less invasive friction measurement protocols compared to traditional ones, and can vastly benefit from recent deep learning advances. Such a novel measurement strategy however proves challenging, as no large labelled dataset for cloth contact exists, and creating one would require thousands of physics workbench measurements with broad coverage of cloth-material pairs. Using synthetic data instead is only possible assuming the availability of a soft-body mechanical simulator with true-to-life friction physics accuracy, yet to be verified. We propose a first vision-based measurement network for friction between cloth and a substrate, using a simple and repeatable video acquisition protocol. We train our network on purely synthetic data generated by a state-of-the-art frictional contact simulator, which we carefully calibrate and validate against real experiments under controlled conditions. We show promising results on a large set of contact pairs between real cloth samples and various kinds of substrates, with 93.6% of all measurements predicted within 0.1 range of standard physics bench measurements.
Visual-Textual Capsule Routing for Text-Based Video Segmentation
Authors: Bruce McIntosh,  Kevin Duarte,  Yogesh S Rawat,  Mubarak Shah
Date: 2020-06-01 00:00:00
Proceeding: CVPR 2020 6
Tasks: Action Localization, Referring Expression Segmentation, Sentence, Video Segmentation, Video Semantic Segmentation

Joint understanding of vision and natural language is a challenging problem with a wide range of applications in artificial intelligence. In this work, we focus on integration of video and text for the task of actor and action video segmentation from a sentence. We propose a capsule-based approach which performs pixel-level localization based on a natural language query describing the actor of interest. We encode both the video and textual input in the form of capsules, which provide a more effective representation in comparison with standard convolution based features. Our novel visual-textual routing mechanism allows for the fusion of video and text capsules to successfully localize the actor and action. The existing works on actor-action localization are mainly focused on localization in a single frame instead of the full video. Different from existing works, we propose to perform the localization on all frames of the video. To validate the potential of the proposed network for actor and action video localization, we extend an existing actor-action dataset (A2D) with annotations for all the frames. The experimental evaluation demonstrates the effectiveness of our capsule network for text selective actor and action localization in videos. The proposed method also improves upon the performance of the existing state-of-the art works on single frame-based localization.
Counterfactual Vision and Language Learning
Authors: Ehsan Abbasnejad,  Damien Teney,  Amin Parvaneh,  Javen Shi,  Anton van den Hengel
Date: 2020-06-01 00:00:00
Proceeding: CVPR 2020 6
Tasks: counterfactual, Question Answering, Visual Question Answering, Visual Question Answering (VQA)

The ongoing success of visual question answering methods has been somwehat surprising given that, at its most general, the problem requires understanding the entire variety of both visual and language stimuli. It is particularly remarkable that this success has been achieved on the basis of comparatively small datasets, given the scale of the problem. One explanation is that this has been accomplished partly by exploiting bias in the datasets rather than developing deeper multi-modal reasoning. This fundamentally limits the generalization of the method, and thus its practical applicability. We propose a method that addresses this problem by introducing counterfactuals in the training. In doing so we leverage structural causal models for counterfactual evaluation to formulate alternatives, for instance, questions that could be asked of the same image set. We show that simulating plausible alternative training data through this process results in better generalization.
TA-Student VQA: Multi-Agents Training by Self-Questioning
Authors: Peixi Xiong,  Ying Wu
Date: 2020-06-01 00:00:00
Proceeding: CVPR 2020 6
Tasks: Diversity, Question Answering, Visual Question Answering, Visual Question Answering (VQA)

There are two main challenges in Visual Question Answering (VQA). The first one is that each model obtains its strengths and shortcomings when applied to several questions; what is more, the "ceiling effect" for specific questions is difficult to overcome with simple consecutive training. The second challenge is that even the state-of-the-art dataset is of large scale, questions targeted at a single image are off in format and lack diversity in content. We introduce our self-questioning model with multi-agent training: TA-student VQA. This framework differs from standard VQA algorithms by involving question-generating mechanisms and collaborative learning questions between question-answering agents. Thus, TA-student VQA overcomes the limitation of the content diversity and format variation of questions and improves the overall performance of multiple question-answering agents. We evaluate our model on VQA-v2, which outperforms algorithms without such mechanisms. In addition, TA-student VQA achieves a greater model capacity, allowing it to answer more generated questions in addition to those in the annotated datasets.
Improving Convolutional Networks With Self-Calibrated Convolutions
Authors: Jiang-Jiang Liu,  Qibin Hou,  Ming-Ming Cheng,  Changhu Wang,  Jiashi Feng
Date: 2020-06-01 00:00:00
Proceeding: CVPR 2020 6
Tasks: Instance Segmentation, Keypoint Detection, object-detection, Object Detection, Representation Learning, Semantic Segmentation

Recent advances on CNNs are mostly devoted to designing more complex architectures to enhance their representation learning capacity. In this paper, we consider how to improve the basic convolutional feature transformation process of CNNs without tuning the model architectures. To this end, we present a novel self-calibrated convolutions that explicitly expand fields-of-view of each convolutional layers through internal communications and hence enrich the output features. In particular, unlike the standard convolutions that fuse spatial and channel-wise information using small kernels (e.g., 3x3), self-calibrated convolutions adaptively build long-range spatial and inter-channel dependencies around each spatial location through a novel self-calibration operation. Thus, it can help CNNs generate more discriminative representations by explicitly incorporating richer information. Our self-calibrated convolution design is simple and generic, and can be easily applied to augment standard convolutional layers without introducing extra parameters and complexity. Extensive experiments demonstrate that when applying self-calibrated convolutions into different backbones, our networks can significantly improve the baseline models in a variety of vision tasks, including image recognition, object detection, instance segmentation, and keypoint detection, with no need to change the network architectures. We hope this work could provide a promising way for future research in designing novel convolutional feature transformations for improving convolutional networks. Code is available on the project page.
One-Shot Adversarial Attacks on Visual Tracking With Dual Attention
Authors: Xuesong Chen,  Xiyu Yan,  Feng Zheng,  Yong Jiang,  Shu-Tao Xia,  Yong Zhao,  Rongrong Ji
Date: 2020-06-01 00:00:00
Proceeding: CVPR 2020 6
Tasks: Adversarial Attack, Object, Object Tracking, Visual Object Tracking, Visual Tracking

Almost all adversarial attacks in computer vision are aimed at pre-known object categories, which could be offline trained for generating perturbations. But as for visual object tracking, the tracked target categories are normally unknown in advance. However, the tracking algorithms also have potential risks of being attacked, which could be maliciously used to fool the surveillance systems. Meanwhile, it is still a challenging task that adversarial attacks on tracking since it has the free-model tracked target. Therefore, to help draw more attention to the potential risks, we study adversarial attacks on tracking algorithms. In this paper, we propose a novel one-shot adversarial attack method to generate adversarial examples for free-model single object tracking, where merely adding slight perturbations on the target patch in the initial frame causes state-of-the-art trackers to lose the target in subsequent frames. Specifically, the optimization objective of the proposed attack consists of two components and leverages the dual attention mechanisms. The first component adopts a targeted attack strategy by optimizing the batch confidence loss with confidence attention while the second one applies a general perturbation strategy by optimizing the feature loss with channel attention. Experimental results show that our approach can significantly lower the accuracy of the most advanced Siamese network-based trackers on three benchmarks.
Action Genome: Actions As Compositions of Spatio-Temporal Scene Graphs
Authors: Jingwei Ji,  Ranjay Krishna,  Li Fei-Fei,  Juan Carlos Niebles
Date: 2020-06-01 00:00:00
Proceeding: CVPR 2020 6
Tasks: Action Recognition, Few-Shot action recognition, Few Shot Action Recognition, Spatio-temporal Scene Graphs

Action recognition has typically treated actions and activities as monolithic events that occur in videos. However, there is evidence from Cognitive Science and Neuroscience that people actively encode activities into consistent hierarchical part structures. However, in Computer Vision, few explorations on representations that encode event partonomies have been made. Inspired by evidence that the prototypical unit of an event is an action-object interaction, we introduce Action Genome, a representation that decomposes actions into spatio-temporal scene graphs. Action Genome captures changes between objects and their pairwise relationships while an action occurs. It contains 10K videos with 0.4M objects and 1.7M visual relationships annotated. With Action Genome, we extend an existing action recognition model by incorporating scene graphs as spatio-temporal feature banks to achieve better performance on the Charades dataset. Next, by decomposing and learning the temporal changes in visual relationships that result in an action, we demonstrate the utility of a hierarchical event decomposition by enabling few-shot action recognition, achieving 42.7% mAP using as few as 10 examples. Finally, we benchmark existing scene graph models on the new task of spatio-temporal scene graph prediction.