逼真的触觉需要高保真的身体建模和忠实的驾驶才能使动态合成的外观与现实无法区分。在这项工作中，我们提出了一个端到端框架，该框架解决了建模和推动真实人的全身化身方面的两个核心挑战。一个挑战是驾驶头像，同时忠实地遵守细节和动态，而这些细节和动态无法被全球低维参数化（例如身体姿势）所捕捉。我们的方法支持驾驶穿着皱纹和运动的衣服化身，而真正的驾驶表演者展出了训练语料库。与现有的全局状态表示或非参数屏幕空间方法不同，我们介绍了Texel对准功能 - 一种本地化表示，可以利用基于骨架的参数模型的结构先验和同时观察到的稀疏图像信号。另一个挑战是建模临时连贯的衣服头像，通常需要精确的表面跟踪。为了避免这种情况，我们通过将体积原语的混合物扩展到清晰的物体，提出了一种新型的体积化头像表示。通过明确合并表达，我们的方法自然而然地概括了看不见的姿势。我们还介绍了局部视点条件，从而导致了依赖视图的外观的概括。拟议的体积表示不需要高质量的网格跟踪作为先决条件，并且与基于网格的对应物相比，具有显着的质量改进。在我们的实验中，我们仔细研究了我们的设计选择，并证明了方法的功效，超过了最新方法在挑战驾驶方案方面的最新方法。

尽管最近在开发动画全身化身方面取得了进展，但服装的现实建模（人类自我表达的核心方面之一）仍然是一个开放的挑战。最先进的物理模拟方法可以以交互速度产生现实行为的服装几何形状。但是，建模光真逼真的外观通常需要基于物理的渲染，这对于交互式应用来说太昂贵了。另一方面，数据驱动的深度外观模型能够有效地产生逼真的外观，但在合成高度动态服装的几何形状和处理具有挑战性的身体套构型方面挣扎。为此，我们通过对服装的明确建模介绍了姿势驱动的化身，这些化身表现出逼真的服装动力学和从现实世界数据中学到的逼真的外观。关键的想法是引入一个在显式几何形状之上运行的神经服装外观模型：在火车时，我们使用高保真跟踪，而在动画时期，我们依靠物理模拟的几何形状。我们的关键贡献是一个具有物理启发的外观网络，能够生成具有视图依赖性和动态阴影效果的影像逼真的外观，即使对于看不见的身体透明构型也是如此。我们对我们的模型进行了彻底的评估，并在几种受试者和不同类型的衣服上展示了不同的动画结果。与以前关于影迷全身化身的工作不同，我们的方法甚至可以为宽松的衣服产生更丰富的动力和更现实的变形。我们还证明，我们的配方自然允许服装与不同人的头像一起使用，同时保持完全动画，因此首次可以采用新颖的衣服来实现逼真的化身。

虚拟网格是在线通信的未来。服装是一个人身份和自我表达的重要组成部分。然而，目前，在培训逼真的布置动画的远程介绍模型的必需分子和准确性中，目前无法使用注册衣服的地面真相数据。在这里，我们提出了一条端到端的管道，用于建造可驱动的服装代表。我们方法的核心是一种多视图图案的布跟踪算法，能够以高精度捕获变形。我们进一步依靠跟踪方法生产的高质量数据来构建服装头像：一件衣服的表达和完全驱动的几何模型。可以使用一组稀疏的视图来对所得模型进行动画，并产生高度逼真的重建，这些重建忠于驾驶信号。我们证明了管道对现实的虚拟电视应用程序的功效，在该应用程序中，从两种视图中重建了衣服，并且用户可以根据自己的意愿进行选择和交换服装设计。此外，当仅通过身体姿势驱动时，我们表现出一个具有挑战性的场景，我们可驾驶的服装Avatar能够生产出比最先进的面包质量明显更高的逼真的布几何形状。

Many problems in machine learning involve bilevel optimization (BLO), including hyperparameter optimization, meta-learning, and dataset distillation. Bilevel problems consist of two nested sub-problems, called the outer and inner problems, respectively. In practice, often at least one of these sub-problems is overparameterized. In this case, there are many ways to choose among optima that achieve equivalent objective values. Inspired by recent studies of the implicit bias induced by optimization algorithms in single-level optimization, we investigate the implicit bias of gradient-based algorithms for bilevel optimization. We delineate two standard BLO methods -- cold-start and warm-start -- and show that the converged solution or long-run behavior depends to a large degree on these and other algorithmic choices, such as the hypergradient approximation. We also show that the inner solutions obtained by warm-start BLO can encode a surprising amount of information about the outer objective, even when the outer parameters are low-dimensional. We believe that implicit bias deserves as central a role in the study of bilevel optimization as it has attained in the study of single-level neural net optimization.

By optimizing the rate-distortion-realism trade-off, generative compression approaches produce detailed, realistic images, even at low bit rates, instead of the blurry reconstructions produced by rate-distortion optimized models. However, previous methods do not explicitly control how much detail is synthesized, which results in a common criticism of these methods: users might be worried that a misleading reconstruction far from the input image is generated. In this work, we alleviate these concerns by training a decoder that can bridge the two regimes and navigate the distortion-realism trade-off. From a single compressed representation, the receiver can decide to either reconstruct a low mean squared error reconstruction that is close to the input, a realistic reconstruction with high perceptual quality, or anything in between. With our method, we set a new state-of-the-art in distortion-realism, pushing the frontier of achievable distortion-realism pairs, i.e., our method achieves better distortions at high realism and better realism at low distortion than ever before.

In this paper, we introduce neural texture learning for 6D object pose estimation from synthetic data and a few unlabelled real images. Our major contribution is a novel learning scheme which removes the drawbacks of previous works, namely the strong dependency on co-modalities or additional refinement. These have been previously necessary to provide training signals for convergence. We formulate such a scheme as two sub-optimisation problems on texture learning and pose learning. We separately learn to predict realistic texture of objects from real image collections and learn pose estimation from pixel-perfect synthetic data. Combining these two capabilities allows then to synthesise photorealistic novel views to supervise the pose estimator with accurate geometry. To alleviate pose noise and segmentation imperfection present during the texture learning phase, we propose a surfel-based adversarial training loss together with texture regularisation from synthetic data. We demonstrate that the proposed approach significantly outperforms the recent state-of-the-art methods without ground-truth pose annotations and demonstrates substantial generalisation improvements towards unseen scenes. Remarkably, our scheme improves the adopted pose estimators substantially even when initialised with much inferior performance.

Fine-grained semantic segmentation of a person's face and head, including facial parts and head components, has progressed a great deal in recent years. However, it remains a challenging task, whereby considering ambiguous occlusions and large pose variations are particularly difficult. To overcome these difficulties, we propose a novel framework termed Mask-FPAN. It uses a de-occlusion module that learns to parse occluded faces in a semi-supervised way. In particular, face landmark localization, face occlusionstimations, and detected head poses are taken into account. A 3D morphable face model combined with the UV GAN improves the robustness of 2D face parsing. In addition, we introduce two new datasets named FaceOccMask-HQ and CelebAMaskOcc-HQ for face paring work. The proposed Mask-FPAN framework addresses the face parsing problem in the wild and shows significant performance improvements with MIOU from 0.7353 to 0.9013 compared to the state-of-the-art on challenging face datasets.

Deep unfolding networks (DUNs) have proven to be a viable approach to compressive sensing (CS). In this work, we propose a DUN called low-rank CS network (LR-CSNet) for natural image CS. Real-world image patches are often well-represented by low-rank approximations. LR-CSNet exploits this property by adding a low-rank prior to the CS optimization task. We derive a corresponding iterative optimization procedure using variable splitting, which is then translated to a new DUN architecture. The architecture uses low-rank generation modules (LRGMs), which learn low-rank matrix factorizations, as well as gradient descent and proximal mappings (GDPMs), which are proposed to extract high-frequency features to refine image details. In addition, the deep features generated at each reconstruction stage in the DUN are transferred between stages to boost the performance. Our extensive experiments on three widely considered datasets demonstrate the promising performance of LR-CSNet compared to state-of-the-art methods in natural image CS.

The number of international benchmarking competitions is steadily increasing in various fields of machine learning (ML) research and practice. So far, however, little is known about the common practice as well as bottlenecks faced by the community in tackling the research questions posed. To shed light on the status quo of algorithm development in the specific field of biomedical imaging analysis, we designed an international survey that was issued to all participants of challenges conducted in conjunction with the IEEE ISBI 2021 and MICCAI 2021 conferences (80 competitions in total). The survey covered participants' expertise and working environments, their chosen strategies, as well as algorithm characteristics. A median of 72% challenge participants took part in the survey. According to our results, knowledge exchange was the primary incentive (70%) for participation, while the reception of prize money played only a minor role (16%). While a median of 80 working hours was spent on method development, a large portion of participants stated that they did not have enough time for method development (32%). 25% perceived the infrastructure to be a bottleneck. Overall, 94% of all solutions were deep learning-based. Of these, 84% were based on standard architectures. 43% of the respondents reported that the data samples (e.g., images) were too large to be processed at once. This was most commonly addressed by patch-based training (69%), downsampling (37%), and solving 3D analysis tasks as a series of 2D tasks. K-fold cross-validation on the training set was performed by only 37% of the participants and only 50% of the participants performed ensembling based on multiple identical models (61%) or heterogeneous models (39%). 48% of the respondents applied postprocessing steps.

Modern machine learning pipelines are limited due to data availability, storage quotas, privacy regulations, and expensive annotation processes. These constraints make it difficult or impossible to maintain a large-scale model trained on growing annotation sets. Continual learning directly approaches this problem, with the ultimate goal of devising methods where a neural network effectively learns relevant patterns for new (unseen) classes without significantly altering its performance on previously learned ones. In this paper, we address the problem of continual learning for video data. We introduce PIVOT, a novel method that leverages the extensive knowledge in pre-trained models from the image domain, thereby reducing the number of trainable parameters and the associated forgetting. Unlike previous methods, ours is the first approach that effectively uses prompting mechanisms for continual learning without any in-domain pre-training. Our experiments show that PIVOT improves state-of-the-art methods by a significant 27% on the 20-task ActivityNet setup.