虽然先前以语音为导向的说话面部生成方法在改善合成视频的视觉质量和唇部同步质量方面取得了重大进展，但它们对唇部运动的关注较少，从而极大地破坏了说话面部视频的真实性。是什么导致运动烦恼，以及如何减轻问题？在本文中，我们基于最先进的管道对运动抖动问题进行系统分析，该管道使用3D面表示桥接输入音频和输出视频，并通过一系列有效的设计来改善运动稳定性。我们发现，几个问题可能会导致综合说话的面部视频中的烦恼：1）输入3D脸部表示的烦恼； 2）训练推导不匹配； 3）视频帧之间缺乏依赖建模。因此，我们提出了三种有效的解决方案来解决此问题：1）我们提出了一个基于高斯的自适应平滑模块，以使3D面部表征平滑以消除输入中的抖动； 2）我们在训练中对神经渲染器的输入数据增加了增强的侵蚀，以模拟推理中的变形以减少不匹配； 3）我们开发了一个音频融合的变压器生成器，以模拟视频帧之间的依赖性。此外，考虑到没有现成的指标来测量说话面部视频中的运动抖动，我们设计了一个客观的度量标准（运动稳定性指数，MSI），可以通过计算方差加速度的倒数来量化运动抖动。广泛的实验结果表明，我们方法对运动稳定的面部视频生成的优越性，其质量比以前的系统更好。

注释的医学图像昂贵，有时甚至无法在一定程度上获得地标检测精度。半监督学习通过利用未标记的数据来了解解剖标志性的人口结构来减轻对大规模注释数据的依赖。全局形状约束是解剖标识的固有属性，为更加一致的伪标签提供了有价值的指导，这些指南在先前的半监督方法中被忽略。在本文中，我们通过完全考虑全局形状约束，提出了一种用于半监控地标检测的模型 - 不可知的形状调节的自我训练框架。具体而言，为了确保伪标签是可靠且保持一致的，基于PCA的形状模型调整伪标签并消除异常。一种新的区域注意力损失，使网络自动关注伪标签周围的结构一致区域。广泛的实验表明，我们的方法优于其他半监督方法，并在三个医学图像数据集中实现了显着的改进。此外，我们的框架是灵活的，可用作集成到最具监控方法的即插即用模块，以进一步提高性能。

在本文中，我们建议使用注意机制和全球环境进行图像分类的一般框架，该框架可以与各种网络体系结构结合起来以提高其性能。为了调查全球环境的能力，我们比较了四个数学模型，并观察到分开的条件生成模型中编码的全球环境可以提供更多的指导，因为“知道什么是任务无关紧要的，也将知道什么是相关的”。基于此观察结果，我们定义了一个新型的分离全球环境（CDGC），并设计了一个深层网络来获得它。通过参加CDGC，基线网络可以更准确地识别感兴趣的对象，从而改善性能。我们将框架应用于许多不同的网络体系结构，并与四个公开可用数据集的最新框架进行比较。广泛的结果证明了我们方法的有效性和优势。代码将在纸上接受公开。

Talking face generation aims at generating photo-realistic video portraits of a target person driven by input audio. Due to its nature of one-to-many mapping from the input audio to the output video (e.g., one speech content may have multiple feasible visual appearances), learning a deterministic mapping like previous works brings ambiguity during training, and thus causes inferior visual results. Although this one-to-many mapping could be alleviated in part by a two-stage framework (i.e., an audio-to-expression model followed by a neural-rendering model), it is still insufficient since the prediction is produced without enough information (e.g., emotions, wrinkles, etc.). In this paper, we propose MemFace to complement the missing information with an implicit memory and an explicit memory that follow the sense of the two stages respectively. More specifically, the implicit memory is employed in the audio-to-expression model to capture high-level semantics in the audio-expression shared space, while the explicit memory is employed in the neural-rendering model to help synthesize pixel-level details. Our experimental results show that our proposed MemFace surpasses all the state-of-the-art results across multiple scenarios consistently and significantly.

Deep learning models can achieve high accuracy when trained on large amounts of labeled data. However, real-world scenarios often involve several challenges: Training data may become available in installments, may originate from multiple different domains, and may not contain labels for training. Certain settings, for instance medical applications, often involve further restrictions that prohibit retention of previously seen data due to privacy regulations. In this work, to address such challenges, we study unsupervised segmentation in continual learning scenarios that involve domain shift. To that end, we introduce GarDA (Generative Appearance Replay for continual Domain Adaptation), a generative-replay based approach that can adapt a segmentation model sequentially to new domains with unlabeled data. In contrast to single-step unsupervised domain adaptation (UDA), continual adaptation to a sequence of domains enables leveraging and consolidation of information from multiple domains. Unlike previous approaches in incremental UDA, our method does not require access to previously seen data, making it applicable in many practical scenarios. We evaluate GarDA on two datasets with different organs and modalities, where it substantially outperforms existing techniques.

The development of social media user stance detection and bot detection methods rely heavily on large-scale and high-quality benchmarks. However, in addition to low annotation quality, existing benchmarks generally have incomplete user relationships, suppressing graph-based account detection research. To address these issues, we propose a Multi-Relational Graph-Based Twitter Account Detection Benchmark (MGTAB), the first standardized graph-based benchmark for account detection. To our knowledge, MGTAB was built based on the largest original data in the field, with over 1.55 million users and 130 million tweets. MGTAB contains 10,199 expert-annotated users and 7 types of relationships, ensuring high-quality annotation and diversified relations. In MGTAB, we extracted the 20 user property features with the greatest information gain and user tweet features as the user features. In addition, we performed a thorough evaluation of MGTAB and other public datasets. Our experiments found that graph-based approaches are generally more effective than feature-based approaches and perform better when introducing multiple relations. By analyzing experiment results, we identify effective approaches for account detection and provide potential future research directions in this field. Our benchmark and standardized evaluation procedures are freely available at: https://github.com/GraphDetec/MGTAB.

As one of the prevalent methods to achieve automation systems, Imitation Learning (IL) presents a promising performance in a wide range of domains. However, despite the considerable improvement in policy performance, the corresponding research on the explainability of IL models is still limited. Inspired by the recent approaches in explainable artificial intelligence methods, we proposed a model-agnostic explaining framework for IL models called R2RISE. R2RISE aims to explain the overall policy performance with respect to the frames in demonstrations. It iteratively retrains the black-box IL model from the randomized masked demonstrations and uses the conventional evaluation outcome environment returns as the coefficient to build an importance map. We also conducted experiments to investigate three major questions concerning frames' importance equality, the effectiveness of the importance map, and connections between importance maps from different IL models. The result shows that R2RISE successfully distinguishes important frames from the demonstrations.

Compressed videos often exhibit visually annoying artifacts, known as Perceivable Encoding Artifacts (PEAs), which dramatically degrade video visual quality. Subjective and objective measures capable of identifying and quantifying various types of PEAs are critical in improving visual quality. In this paper, we investigate the influence of four spatial PEAs (i.e. blurring, blocking, bleeding, and ringing) and two temporal PEAs (i.e. flickering and floating) on video quality. For spatial artifacts, we propose a visual saliency model with a low computational cost and higher consistency with human visual perception. In terms of temporal artifacts, self-attention based TimeSFormer is improved to detect temporal artifacts. Based on the six types of PEAs, a quality metric called Saliency-Aware Spatio-Temporal Artifacts Measurement (SSTAM) is proposed. Experimental results demonstrate that the proposed method outperforms state-of-the-art metrics. We believe that SSTAM will be beneficial for optimizing video coding techniques.

We propose a distributionally robust return-risk model for Markov decision processes (MDPs) under risk and reward ambiguity. The proposed model optimizes the weighted average of mean and percentile performances, and it covers the distributionally robust MDPs and the distributionally robust chance-constrained MDPs (both under reward ambiguity) as special cases. By considering that the unknown reward distribution lies in a Wasserstein ambiguity set, we derive the tractable reformulation for our model. In particular, we show that that the return-risk model can also account for risk from uncertain transition kernel when one only seeks deterministic policies, and that a distributionally robust MDP under the percentile criterion can be reformulated as its nominal counterpart at an adjusted risk level. A scalable first-order algorithm is designed to solve large-scale problems, and we demonstrate the advantages of our proposed model and algorithm through numerical experiments.

Witnessing the impressive achievements of pre-training techniques on large-scale data in the field of computer vision and natural language processing, we wonder whether this idea could be adapted in a grab-and-go spirit, and mitigate the sample inefficiency problem for visuomotor driving. Given the highly dynamic and variant nature of the input, the visuomotor driving task inherently lacks view and translation invariance, and the visual input contains massive irrelevant information for decision making, resulting in predominant pre-training approaches from general vision less suitable for the autonomous driving task. To this end, we propose PPGeo (Policy Pre-training via Geometric modeling), an intuitive and straightforward fully self-supervised framework curated for the policy pretraining in visuomotor driving. We aim at learning policy representations as a powerful abstraction by modeling 3D geometric scenes on large-scale unlabeled and uncalibrated YouTube driving videos. The proposed PPGeo is performed in two stages to support effective self-supervised training. In the first stage, the geometric modeling framework generates pose and depth predictions simultaneously, with two consecutive frames as input. In the second stage, the visual encoder learns driving policy representation by predicting the future ego-motion and optimizing with the photometric error based on current visual observation only. As such, the pre-trained visual encoder is equipped with rich driving policy related representations and thereby competent for multiple visuomotor driving tasks. Extensive experiments covering a wide span of challenging scenarios have demonstrated the superiority of our proposed approach, where improvements range from 2% to even over 100% with very limited data. Code and models will be available at https://github.com/OpenDriveLab/PPGeo.