本文旨在解决多视图设置下图像变形的新任务，该任务将两组多视图像作为输入，并生成中间渲染，不仅在两个输入集之间表现出平滑的过渡，还可以确保在不同视图的视觉一致性之间任何过渡状态。为了实现这一目标，我们提出了一种称为多视频再生变形的新颖方法，该方法将变形过程制定为优化，以求解刚性转换和最佳传输插值。鉴于源场和目标场景的多视图输入图像，我们首先学习了一个体积表示，该图表为每个场景的几何形状和外观建模以实现新视图的渲染。然后，通过求解瓦斯林指标的两个体积表示之间的最佳运输来获得两个场景之间的变形。我们的方法不依赖用户指定的对应关系或2D/3D输入网格，并且我们不假定源场和目标场景的任何预定义类别。所提出的一致性插值方案直接在多视图图像上起作用，以产生多视图自由形式变形的新颖且视觉上合理的效果。

我们提出了一种可自行的方法Mask2Hand，该方法学会了解决从2D二进制式掩护的手动剪影/阴影中预测3D手姿势和形状的具有挑战性的任务，而无需其他手动注释的数据。鉴于摄像机空间中的固有摄像头参数和参数手模型，我们采用可区分的渲染技术将3D估计投影到2D二进制轮廓空间上。通过在渲染的轮廓和输入二进制面膜之间应用量身定制的损失组合，我们能够将自我借记机制集成到我们的端到端优化过程中，以限制全球网格注册和手部姿势估计。实验表明，我们的方法将单个二进制掩码作为输入，可以在不对齐和对齐设置作为需要RGB或深度输入的最新方法上实现可比的预测准确性。我们的代码可在https://github.com/lijenchang/mask2hand上找到。

我们提出了一种姿势自适应少量射门学习程序和两阶段数据插值正规化，被称为姿势自适应双混合（PADMIX），用于单图像3D重建。虽然通过插值特征标签对的增强在分类任务中有效，但它们在形状预测中缺失，可能由于两个图像和卷渲染观点未知时的两个图像和卷之间的不一致而缺失。 Padmix针对此问题，使用两组混合过程顺序执行。我们首先执行输入混合，该输入混合，与姿势自适应学习过程相结合，有助于学习2D特征提取和构成自适应潜在编码。 StageWise训练允许我们建立在构成不变的表示上，以在特征和地面卷之间的一对一对应项下执行后续潜在混合。 Padmix在ShapEnet​​ DataSet上的几个拍摄设置上显着优于先前的文献，并在更具挑战性的真实世界Pix3D数据集中设置新的基准。

我们介绍了一种超快速的收敛方法来重建从一组图像中捕获具有已知姿势的场景的图像的每场辐射场。该任务通常适用于新颖的视图综合，最近是由神经辐射领域（NERF）彻底改革为其最先进的质量和灵活性。然而，NERF及其变体需要漫长的训练时间来为单个场景的数小时到几天。相比之下，我们的方法实现了NERF相当的质量，并通过单个GPU在不到15分钟内从划痕中迅速收敛。我们采用由密度体素网格组成的表示，用于场景几何形状和具有浅网络的特征体素网格，用于复杂的视图依赖性外观。用明确和离散化卷表示的建模并不是新的，但我们提出了两种简单而非琐碎的技术，有助于快速收敛速度和高质量的输出。首先，我们介绍了体素密度的激活后插值，其能够以较低的网格分辨率产生尖锐的表面。其次，直接体素密度优化容易发生次优几何解决方案，因此我们通过施加多个前沿来强制优化过程。最后，对五个内向的基准评估表明，我们的方法匹配，如果没有超越Nerf的质量，但它只需15分钟即可从头开始训练新场景。

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.