4,450 research outputs found

    Action Recognition in Videos: from Motion Capture Labs to the Web

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    This paper presents a survey of human action recognition approaches based on visual data recorded from a single video camera. We propose an organizing framework which puts in evidence the evolution of the area, with techniques moving from heavily constrained motion capture scenarios towards more challenging, realistic, "in the wild" videos. The proposed organization is based on the representation used as input for the recognition task, emphasizing the hypothesis assumed and thus, the constraints imposed on the type of video that each technique is able to address. Expliciting the hypothesis and constraints makes the framework particularly useful to select a method, given an application. Another advantage of the proposed organization is that it allows categorizing newest approaches seamlessly with traditional ones, while providing an insightful perspective of the evolution of the action recognition task up to now. That perspective is the basis for the discussion in the end of the paper, where we also present the main open issues in the area.Comment: Preprint submitted to CVIU, survey paper, 46 pages, 2 figures, 4 table

    Face analysis and deepfake detection

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    This thesis concerns deep-learning-based face-related research topics. We explore how to improve the performance of several face systems when confronting challenging variations. In Chapter 1, we provide an introduction and background information on the theme, and we list the main research questions of this dissertation. In Chapter 2, we provide a synthetic face data generator with fully controlled variations and proposed a detailed experimental comparison of main characteristics that influence face detection performance. The result shows that our synthetic dataset could complement face detectors to become more robust against specific features in the real world. Our analysis also reveals that a variety of data augmentation is necessary to address differences in performance. In Chapter 3, we propose an age estimation method for handling large pose variations for unconstrained face images. A Wasserstein-based GAN model is used to complete the full uv texture presentation. The proposed AgeGAN method simultaneously learns to capture the facial uv texture map and age characteristics.In Chapter 4, we propose a maximum mean discrepancy (MMD) based cross-domain face forgery detection. The center and triplet losses are also incorporated to ensure that the learned features are shared by multiple domains and provide better generalization abilities to unseen deep fake samples. In Chapter 5, we introduce an end-to-end framework to predict ages from face videos. Clustering based transfer learning is used to provide proper prediction for imbalanced datasets

    Multimodal human hand motion sensing and analysis - a review

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    Multimedia Forensics

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    This book is open access. Media forensics has never been more relevant to societal life. Not only media content represents an ever-increasing share of the data traveling on the net and the preferred communications means for most users, it has also become integral part of most innovative applications in the digital information ecosystem that serves various sectors of society, from the entertainment, to journalism, to politics. Undoubtedly, the advances in deep learning and computational imaging contributed significantly to this outcome. The underlying technologies that drive this trend, however, also pose a profound challenge in establishing trust in what we see, hear, and read, and make media content the preferred target of malicious attacks. In this new threat landscape powered by innovative imaging technologies and sophisticated tools, based on autoencoders and generative adversarial networks, this book fills an important gap. It presents a comprehensive review of state-of-the-art forensics capabilities that relate to media attribution, integrity and authenticity verification, and counter forensics. Its content is developed to provide practitioners, researchers, photo and video enthusiasts, and students a holistic view of the field

    Interactive videos: Plausible video editing using sparse structure points

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    Video remains the method of choice for capturing temporal events. However, without access to the underlying 3D scene models, it remains difficult to make object level edits in a single video or across multiple videos. While it may be possible to explicitly reconstruct the 3D geometries to facilitate these edits, such a workflow is cumbersome, expensive, and tedious. In this work, we present a much simpler workflow to create plausible editing and mixing of raw video footage using only sparse structure points (SSP) directly recovered from the raw sequences. First, we utilize user-scribbles to structure the point representations obtained using structure-from-motion on the input videos. The resultant structure points, even when noisy and sparse, are then used to enable various video edits in 3D, including view perturbation, keyframe animation, object duplication and transfer across videos, etc. Specifically, we describe how to synthesize object images from new views adopting a novel image-based rendering technique using the SSPs as proxy for the missing 3D scene information. We propose a structure-preserving image warping on multiple input frames adaptively selected from object video, followed by a spatio-temporally coherent image stitching to compose the final object image. Simple planar shadows and depth maps are synthesized for objects to generate plausible video sequence mimicking real-world interactions. We demonstrate our system on a variety of input videos to produce complex edits, which are otherwise difficult to achieve
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