Dynamic networks have been extensively explored as they can considerably improve the model's representation power with acceptable computational cost. The common practice in implementing dynamic networks is to convert given static layers into fully dynamic ones where all parameters are dynamic and vary with the input. Recent studies empirically show the trend that the more dynamic layers contribute to ever-increasing performance. However, such a fully dynamic setting 1) may cause redundant parameters and high deployment costs, limiting the applicability of dynamic networks to a broader range of tasks and models, and more importantly, 2) contradicts the previous discovery in the human brain that \textit{when human brains process an attention-demanding task, only partial neurons in the task-specific areas are activated by the input, while the rest neurons leave in a baseline state.} Critically, there is no effort to understand and resolve the above contradictory finding, leaving the primal question -- to make the computational parameters fully dynamic or not? -- unanswered. The main contributions of our work are challenging the basic commonsense in dynamic networks, and, proposing and validating the \textsc{cherry hypothesis} -- \textit{A fully dynamic network contains a subset of dynamic parameters that when transforming other dynamic parameters into static ones, can maintain or even exceed the performance of the original network.} Technically, we propose a brain-inspired partially dynamic network, namely PAD-Net, to transform the redundant dynamic parameters into static ones. Also, we further design Iterative Mode Partition to partition the dynamic- and static-subnet, which alleviates the redundancy in traditional fully dynamic networks. Our hypothesis and method are comprehensively supported by large-scale experiments with typical advanced dynamic methods.
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最近,我们看到了照片真实的人类建模和渲染的神经进展取得的巨大进展。但是,将它们集成到现有的下游应用程序中的现有网络管道中仍然具有挑战性。在本文中,我们提出了一种全面的神经方法,用于从密集的多视频视频中对人类表演进行高质量重建,压缩和渲染。我们的核心直觉是用一系列高效的神经技术桥接传统的动画网格工作流程。我们首先引入一个神经表面重建器,以在几分钟内进行高质量的表面产生。它与多分辨率哈希编码的截短签名距离场(TSDF)的隐式体积渲染相结合。我们进一步提出了一个混合神经跟踪器来生成动画网格,该网格将明确的非刚性跟踪与自我监督框架中的隐式动态变形结合在一起。前者将粗糙的翘曲返回到规范空间中,而后者隐含的一个隐含物进一步预测了使用4D哈希编码的位移,如我们的重建器中。然后,我们使用获得的动画网格讨论渲染方案,从动态纹理到各种带宽设置下的Lumigraph渲染。为了在质量和带宽之间取得复杂的平衡,我们通过首先渲染6个虚拟视图来涵盖表演者,然后进行闭塞感知的神经纹理融合,提出一个分层解决方案。我们证明了我们方法在各种平台上的各种基于网格的应用程序和照片真实的自由观看体验中的功效,即,通过移动AR插入虚拟人类的表演,或通过移动AR插入真实环境,或带有VR头戴式的人才表演。
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最近的神经人类表示可以产生高质量的多视图渲染,但需要使用密集的多视图输入和昂贵的培训。因此,它们在很大程度上仅限于静态模型,因为每个帧都是不可行的。我们展示了人类学 - 一种普遍的神经表示 - 用于高保真自由观察动态人类的合成。类似于IBRNET如何通过避免每场景训练来帮助NERF,Humannerf跨多视图输入采用聚合像素对准特征,以及用于解决动态运动的姿势嵌入的非刚性变形场。原始人物员已经可以在稀疏视频输入的稀疏视频输入上产生合理的渲染。为了进一步提高渲染质量,我们使用外观混合模块增强了我们的解决方案,用于组合神经体积渲染和神经纹理混合的益处。各种多视图动态人类数据集的广泛实验证明了我们在挑战运动中合成照片 - 现实自由观点的方法和非常稀疏的相机视图输入中的普遍性和有效性。
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b) MVS-NeRF no fine-tuning c) MVS-NeRF 6 min fine-tuning d) NeRF 5.1h optimization a) Source views SSIM:0.766 SSIM: 0.923 SSIM:0.924 * Equal contribution Research done when Anpei Chen was in a remote internship with UCSD.generalizable radiance field reconstruction. Moreover, if dense images are captured, our estimated radiance field representation can be easily fine-tuned; this leads to fast per-scene reconstruction with higher rendering quality and substantially less optimization time than NeRF.
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非结构化的文本中存在大量的位置信息,例如社交媒体帖子,新闻报道,科学文章,网页,旅行博客和历史档案。地理学是指识别文本中的位置参考并识别其地理空间表示的过程。虽然地理标准可以使许多领域受益,但仍缺少特定应用程序的摘要。此外,缺乏对位置参考识别方法的现有方法的全面审查和比较,这是地理验证的第一个和核心步骤。为了填补这些研究空白,这篇综述首先总结了七个典型的地理应用程序域:地理信息检索,灾难管理,疾病监视,交通管理,空间人文,旅游管理和犯罪管理。然后,我们通过将这些方法分类为四个组,以基于规则的基于规则,基于统计学学习的基于统计学学习和混合方法将这些方法分类为四个组,从而回顾了现有的方法参考识别方法。接下来,我们彻底评估了27种最广泛使用的方法的正确性和计算效率,该方法基于26个公共数据集,其中包含不同类型的文本(例如,社交媒体帖子和新闻报道),包含39,736个位置参考。这项彻底评估的结果可以帮助未来的方法论发展以获取位置参考识别,并可以根据应用需求指导选择适当方法的选择。
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本文介绍了一种基于代理的互相关(SBCC)框架,以提高两个图像信号之间的相关性能。 SBCC背后的基本思想是,提供一个原始图像的优化代理滤波器/图像将产生更强大的且更准确的相关信号。 SBCC的互相关估计与由替代丢失和相关稠度损失组成的目标函数。闭合溶液提供有效的估计。为了我们的意外,SBCC框架可以提供替代视图来解释一组广义互相关(GCC)方法并理解参数的含义。在我们的SBCC框架的帮助下,我们进一步提出了四种新的特定互联方法,并提供了一些提高现有GCC方法的建议。值得注意的事实是,通过纳入其他否定的上下文图像,SBCC可以增强相关性鲁棒性。考虑到粒子图像VELOCIMETRY(PIV)的子像素精度和鲁棒性要求,用粒子图像研究了目标函数中的每个术语的贡献。与最先进的基线方法相比,SBCC方法在合成数据集中表现出改善的性能(准确性和鲁棒性)和一些具有挑战性的真实实验PIV病例。
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Unsupervised domain adaptation (UDA) for semantic segmentation is a promising task freeing people from heavy annotation work. However, domain discrepancies in low-level image statistics and high-level contexts compromise the segmentation performance over the target domain. A key idea to tackle this problem is to perform both image-level and feature-level adaptation jointly. Unfortunately, there is a lack of such unified approaches for UDA tasks in the existing literature. This paper proposes a novel UDA pipeline for semantic segmentation that unifies image-level and feature-level adaptation. Concretely, for image-level domain shifts, we propose a global photometric alignment module and a global texture alignment module that align images in the source and target domains in terms of image-level properties. For feature-level domain shifts, we perform global manifold alignment by projecting pixel features from both domains onto the feature manifold of the source domain; and we further regularize category centers in the source domain through a category-oriented triplet loss and perform target domain consistency regularization over augmented target domain images. Experimental results demonstrate that our pipeline significantly outperforms previous methods. In the commonly tested GTA5$\rightarrow$Cityscapes task, our proposed method using Deeplab V3+ as the backbone surpasses previous SOTA by 8%, achieving 58.2% in mIoU.
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Different people speak with diverse personalized speaking styles. Although existing one-shot talking head methods have made significant progress in lip sync, natural facial expressions, and stable head motions, they still cannot generate diverse speaking styles in the final talking head videos. To tackle this problem, we propose a one-shot style-controllable talking face generation framework. In a nutshell, we aim to attain a speaking style from an arbitrary reference speaking video and then drive the one-shot portrait to speak with the reference speaking style and another piece of audio. Specifically, we first develop a style encoder to extract dynamic facial motion patterns of a style reference video and then encode them into a style code. Afterward, we introduce a style-controllable decoder to synthesize stylized facial animations from the speech content and style code. In order to integrate the reference speaking style into generated videos, we design a style-aware adaptive transformer, which enables the encoded style code to adjust the weights of the feed-forward layers accordingly. Thanks to the style-aware adaptation mechanism, the reference speaking style can be better embedded into synthesized videos during decoding. Extensive experiments demonstrate that our method is capable of generating talking head videos with diverse speaking styles from only one portrait image and an audio clip while achieving authentic visual effects. Project Page: https://github.com/FuxiVirtualHuman/styletalk.
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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.
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Increasing research interests focus on sequential recommender systems, aiming to model dynamic sequence representation precisely. However, the most commonly used loss function in state-of-the-art sequential recommendation models has essential limitations. To name a few, Bayesian Personalized Ranking (BPR) loss suffers the vanishing gradient problem from numerous negative sampling and predictionbiases; Binary Cross-Entropy (BCE) loss subjects to negative sampling numbers, thereby it is likely to ignore valuable negative examples and reduce the training efficiency; Cross-Entropy (CE) loss only focuses on the last timestamp of the training sequence, which causes low utilization of sequence information and results in inferior user sequence representation. To avoid these limitations, in this paper, we propose to calculate Cumulative Cross-Entropy (CCE) loss over the sequence. CCE is simple and direct, which enjoys the virtues of painless deployment, no negative sampling, and effective and efficient training. We conduct extensive experiments on five benchmark datasets to demonstrate the effectiveness and efficiency of CCE. The results show that employing CCE loss on three state-of-the-art models GRU4Rec, SASRec, and S3-Rec can reach 125.63%, 69.90%, and 33.24% average improvement of full ranking NDCG@5, respectively. Using CCE, the performance curve of the models on the test data increases rapidly with the wall clock time, and is superior to that of other loss functions in almost the whole process of model training.
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