已被证明在改善神经电机翻译(NMT)系统方面有效的深度编码器,但是当编码器层数超过18时,它达到了翻译质量的上限。更糟糕的是,更深的网络消耗了很多内存,使其无法实现有效地训练。在本文中,我们呈现了共生网络,其包括完整的网络作为共生主网络(M-Net)和另一个具有相同结构的共享子网,但层数较少为共生子网(S-Net)。我们在变压器深度(M-N)架构上采用共生网络,并在NMT中定义M-Net和S-Net之间的特定正则化损耗$ \ mathcal {l} _ {\ tau} $。我们对共生网络进行联合培训,并旨在提高M净性能。我们拟议的培训策略在CMT'14 en-> De,De-> EN和EN-> FR任务的经典培训下将变压器深(12-6)改善了0.61,0.49和0.69 BLEU。此外,我们的变压器深(12-6)甚至优于经典变压器深度(18-6)。
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最近,非自动增加(NAT)模型并行地预测输出,与自回归(AT)模型相比,实现了产生速度的大量改进。在对原始数据上表现更差的同时,大多数NAT模型都被培训为在教师模型生成的蒸馏数据上的学生模型,称为序列级知识蒸馏。提高模型性能的有效培训策略是自蒸馏混合(SDM)培训,预先训练原始数据模型,通过预先训练的模型本身产生蒸馏数据,最后重新列举模型原始数据和蒸馏数据的组合。在这项工作中,我们的目标是查看NAT模型的SDM,但发现直接采用SDM到NAT模型在翻译质量方面没有改进。通过仔细分析,我们观察失效与教师模型与NAT学生模型的建模和确认偏差相关。基于这些发现,我们提出了一种增强的策略,通过向经典SDM添加两个阶段来提高名为SDMRT的策略:一个是在自蒸馏数据上进行预重磅,另一个是对滤波后的教师蒸馏数据进行微调。我们的结果在多个NAT模型上以0.6至1.2 bleu表示基础。作为另一个奖励,对于迭代细化NAT模型,我们的方法可以在半迭代号内倾斜基线,这意味着2x加速度。
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In recent years, the Transformer architecture has shown its superiority in the video-based person re-identification task. Inspired by video representation learning, these methods mainly focus on designing modules to extract informative spatial and temporal features. However, they are still limited in extracting local attributes and global identity information, which are critical for the person re-identification task. In this paper, we propose a novel Multi-Stage Spatial-Temporal Aggregation Transformer (MSTAT) with two novel designed proxy embedding modules to address the above issue. Specifically, MSTAT consists of three stages to encode the attribute-associated, the identity-associated, and the attribute-identity-associated information from the video clips, respectively, achieving the holistic perception of the input person. We combine the outputs of all the stages for the final identification. In practice, to save the computational cost, the Spatial-Temporal Aggregation (STA) modules are first adopted in each stage to conduct the self-attention operations along the spatial and temporal dimensions separately. We further introduce the Attribute-Aware and Identity-Aware Proxy embedding modules (AAP and IAP) to extract the informative and discriminative feature representations at different stages. All of them are realized by employing newly designed self-attention operations with specific meanings. Moreover, temporal patch shuffling is also introduced to further improve the robustness of the model. Extensive experimental results demonstrate the effectiveness of the proposed modules in extracting the informative and discriminative information from the videos, and illustrate the MSTAT can achieve state-of-the-art accuracies on various standard benchmarks.
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由于激光雷达扫描数据的大规模,噪音和数据不完整,注册Urban Point Clouds是一项艰巨的任务。在本文中,我们提出了SARNET,这是一个新型的语义增强注册网络,旨在在城市规模上实现有效的城市点云的注册。与以前仅在点级空间中构建对应关系的方法不同,我们的方法完全利用语义特征来提高注册精度。具体而言,我们提取具有高级语义分割网络的每点语义标签,并构建先前的语义零件到部分对应关系。然后,我们将语义信息纳入基于学习的注册管道中,该管道由三个核心模块组成:基于语义的最远点采样模块,以有效地滤除异常值和动态对象;一个语义增强的特征提取模块,用于学习更多的判别点描述符;语义改制的转换估计模块,该模块利用先前的语义匹配作为掩码,通过减少错误匹配以更好地收敛来完善点对应关系。我们通过使用来自城市场景的大区域的现实世界数据并将其与替代方法进行比较,从而广泛评估所提出的SARNET。该代码可在https://github.com/wintercodeforeverything/sarnet上找到。
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从单个图像重建高保真3D面部纹理是一个具有挑战性的任务,因为缺乏完整的面部信息和3D面和2D图像之间的域间隙。最新作品通过应用基于代或基于重建的方法来解决面部纹理重建问题。尽管各种方法具有自身的优势,但它们不能恢复高保真和可重新可传送的面部纹理,其中术语“重新可调剂”要求面部质地在空间地完成和与环境照明中脱颖而出。在本文中,我们提出了一种新颖的自我监督学习框架,用于从野外的单视图重建高质量的3D面。我们的主要思想是首先利用先前的一代模块来生产先前的Albedo,然后利用细节细化模块来获得详细的Albedo。为了进一步使面部纹理解开照明,我们提出了一种新颖的详细的照明表示,该表现在一起与详细的Albedo一起重建。我们还在反照侧和照明方面设计了几种正规化损失功能,以便于解散这两个因素。最后,由于可怜的渲染技术,我们的神经网络可以以自我监督的方式有效地培训。关于具有挑战性的数据集的广泛实验表明,我们的框架在定性和定量比较方面显着优于最先进的方法。
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A recent study has shown a phenomenon called neural collapse in that the within-class means of features and the classifier weight vectors converge to the vertices of a simplex equiangular tight frame at the terminal phase of training for classification. In this paper, we explore the corresponding structures of the last-layer feature centers and classifiers in semantic segmentation. Based on our empirical and theoretical analysis, we point out that semantic segmentation naturally brings contextual correlation and imbalanced distribution among classes, which breaks the equiangular and maximally separated structure of neural collapse for both feature centers and classifiers. However, such a symmetric structure is beneficial to discrimination for the minor classes. To preserve these advantages, we introduce a regularizer on feature centers to encourage the network to learn features closer to the appealing structure in imbalanced semantic segmentation. Experimental results show that our method can bring significant improvements on both 2D and 3D semantic segmentation benchmarks. Moreover, our method ranks 1st and sets a new record (+6.8% mIoU) on the ScanNet200 test leaderboard. Code will be available at https://github.com/dvlab-research/Imbalanced-Learning.
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Weakly-supervised object localization aims to indicate the category as well as the scope of an object in an image given only the image-level labels. Most of the existing works are based on Class Activation Mapping (CAM) and endeavor to enlarge the discriminative area inside the activation map to perceive the whole object, yet ignore the co-occurrence confounder of the object and context (e.g., fish and water), which makes the model inspection hard to distinguish object boundaries. Besides, the use of CAM also brings a dilemma problem that the classification and localization always suffer from a performance gap and can not reach their highest accuracy simultaneously. In this paper, we propose a casual knowledge distillation method, dubbed KD-CI-CAM, to address these two under-explored issues in one go. More specifically, we tackle the co-occurrence context confounder problem via causal intervention (CI), which explores the causalities among image features, contexts, and categories to eliminate the biased object-context entanglement in the class activation maps. Based on the de-biased object feature, we additionally propose a multi-teacher causal distillation framework to balance the absorption of classification knowledge and localization knowledge during model training. Extensive experiments on several benchmarks demonstrate the effectiveness of KD-CI-CAM in learning clear object boundaries from confounding contexts and addressing the dilemma problem between classification and localization performance.
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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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In this work, we focus on instance-level open vocabulary segmentation, intending to expand a segmenter for instance-wise novel categories without mask annotations. We investigate a simple yet effective framework with the help of image captions, focusing on exploiting thousands of object nouns in captions to discover instances of novel classes. Rather than adopting pretrained caption models or using massive caption datasets with complex pipelines, we propose an end-to-end solution from two aspects: caption grounding and caption generation. In particular, we devise a joint Caption Grounding and Generation (CGG) framework based on a Mask Transformer baseline. The framework has a novel grounding loss that performs explicit and implicit multi-modal feature alignments. We further design a lightweight caption generation head to allow for additional caption supervision. We find that grounding and generation complement each other, significantly enhancing the segmentation performance for novel categories. We conduct extensive experiments on the COCO dataset with two settings: Open Vocabulary Instance Segmentation (OVIS) and Open Set Panoptic Segmentation (OSPS). The results demonstrate the superiority of our CGG framework over previous OVIS methods, achieving a large improvement of 6.8% mAP on novel classes without extra caption data. Our method also achieves over 15% PQ improvements for novel classes on the OSPS benchmark under various settings.
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Nearest-Neighbor (NN) classification has been proven as a simple and effective approach for few-shot learning. The query data can be classified efficiently by finding the nearest support class based on features extracted by pretrained deep models. However, NN-based methods are sensitive to the data distribution and may produce false prediction if the samples in the support set happen to lie around the distribution boundary of different classes. To solve this issue, we present P3DC-Shot, an improved nearest-neighbor based few-shot classification method empowered by prior-driven data calibration. Inspired by the distribution calibration technique which utilizes the distribution or statistics of the base classes to calibrate the data for few-shot tasks, we propose a novel discrete data calibration operation which is more suitable for NN-based few-shot classification. Specifically, we treat the prototypes representing each base class as priors and calibrate each support data based on its similarity to different base prototypes. Then, we perform NN classification using these discretely calibrated support data. Results from extensive experiments on various datasets show our efficient non-learning based method can outperform or at least comparable to SOTA methods which need additional learning steps.
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