Automatically estimating 3D skeleton, shape, camera viewpoints, and part articulation from sparse in-the-wild image ensembles is a severely under-constrained and challenging problem. Most prior methods rely on large-scale image datasets, dense temporal correspondence, or human annotations like camera pose, 2D keypoints, and shape templates. We propose Hi-LASSIE, which performs 3D articulated reconstruction from only 20-30 online images in the wild without any user-defined shape or skeleton templates. We follow the recent work of LASSIE that tackles a similar problem setting and make two significant advances. First, instead of relying on a manually annotated 3D skeleton, we automatically estimate a class-specific skeleton from the selected reference image. Second, we improve the shape reconstructions with novel instance-specific optimization strategies that allow reconstructions to faithful fit on each instance while preserving the class-specific priors learned across all images. Experiments on in-the-wild image ensembles show that Hi-LASSIE obtains higher quality state-of-the-art 3D reconstructions despite requiring minimum user input.
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本文总结了自动驾驶场景中流行的基于锚的探测器的模型改进和推理时间优化。根据专为通用检测场景而设计的高性能RCNN-RS和Verinanet-RS检测框架,我们研究了一组框架改进,以适应探测器以更好地检测人群场景中的小物体。然后,我们通过扩展输入分辨率和模型大小来提出模型缩放策略,以实现更好的速度准确性权衡曲线。我们在Waymo Open数据集(WOD)的实时2D检测轨道上评估了模型家庭。在V100 GPU的70毫秒/帧延迟约束中,我们最大的Cascade RCNN-RS型号可实现76.9%AP/L1和70.1%AP/L2,在WOD实时2D检测中获得新的最新技术。我们最快的视网膜RS模型达到6.3 ms/帧,同时保持合理的检测精度为50.7%AP/L1和42.9%AP/L2。
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通过手动创建或使用3D扫描工具来创建高质量的铰接3D动物3D模型。因此,从2D图像重建铰接的3D对象的技术至关重要且非常有用。在这项工作中,我们提出了一个实用问题设置,以估算只有几个(10-30)特定动物物种(例如马)的野外图像(Horse)的3D姿势和形状。与依赖于预定义模板形状的现有作品相反,我们不假设任何形式的2D或3D地面真相注释,也不利用任何多视图或时间信息。此外,每个输入图像合奏都可以包含具有不同姿势,背景,照明和纹理的动物实例。我们的主要见解是,与整体动物相比,3D零件的形状要简单得多,并且它们是强大的W.R.T.动物姿势关节。遵循这些见解,我们提出了Lassie,这是一个新颖的优化框架,以最少的用户干预以自我监督的方式发现3D部分。 Lassie背后的关键推动力是使用自我篇幅的深度功能实现2D-3D零件的一致性。与先前的艺术相比,关于Pascal-Part和自我收集的野生动物数据集的实验表明,3D重建以及2D和3D部分的发现都更好。项目页面:chhankyo.github.io/lassie/
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流行的对象检测度量平均精度(3D AP)依赖于预测的边界框和地面真相边界框之间的结合。但是,基于摄像机的深度估计的精度有限,这可能会导致其他合理的预测,这些预测遭受了如此纵向定位错误,被视为假阳性和假阴性。因此,我们提出了流行的3D AP指标的变体,这些变体旨在在深度估计误差方面更具允许性。具体而言,我们新颖的纵向误差耐受度指标,Let-3D-AP和Let-3D-APL,允许预测的边界框的纵向定位误差,最高为给定的公差。所提出的指标已在Waymo Open DataSet 3D摄像头仅检测挑战中使用。我们认为,它们将通过提供更有信息的性能信号来促进仅相机3D检测领域的进步。
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通过对比学习,自我监督学习最近在视觉任务中显示了巨大的潜力,这旨在在数据集中区分每个图像或实例。然而,这种情况级别学习忽略了实例之间的语义关系,有时不希望地从语义上类似的样本中排斥锚,被称为“假否定”。在这项工作中,我们表明,对于具有更多语义概念的大规模数据集来说,虚假否定的不利影响更为重要。为了解决这个问题,我们提出了一种新颖的自我监督的对比学习框架,逐步地检测并明确地去除假阴性样本。具体地,在训练过程之后,考虑到编码器逐渐提高,嵌入空间变得更加语义结构,我们的方法动态地检测增加的高质量假否定。接下来,我们讨论两种策略,以明确地在对比学习期间明确地消除检测到的假阴性。广泛的实验表明,我们的框架在有限的资源设置中的多个基准上表现出其他自我监督的对比学习方法。
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Convolutional neural network-based approaches for semantic segmentation rely on supervision with pixel-level ground truth, but may not generalize well to unseen image domains. As the labeling process is tedious and labor intensive, developing algorithms that can adapt source ground truth labels to the target domain is of great interest. In this paper, we propose an adversarial learning method for domain adaptation in the context of semantic segmentation. Considering semantic segmentations as structured outputs that contain spatial similarities between the source and target domains, we adopt adversarial learning in the output space. To further enhance the adapted model, we construct a multi-level adversarial network to effectively perform output space domain adaptation at different feature levels. Extensive experiments and ablation study are conducted under various domain adaptation settings, including synthetic-to-real and cross-city scenarios. We show that the proposed method performs favorably against the stateof-the-art methods in terms of accuracy and visual quality.
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Modern deep neural networks have achieved superhuman performance in tasks from image classification to game play. Surprisingly, these various complex systems with massive amounts of parameters exhibit the same remarkable structural properties in their last-layer features and classifiers across canonical datasets. This phenomenon is known as "Neural Collapse," and it was discovered empirically by Papyan et al. \cite{Papyan20}. Recent papers have theoretically shown the global solutions to the training network problem under a simplified "unconstrained feature model" exhibiting this phenomenon. We take a step further and prove the Neural Collapse occurrence for deep linear network for the popular mean squared error (MSE) and cross entropy (CE) loss. Furthermore, we extend our research to imbalanced data for MSE loss and present the first geometric analysis for Neural Collapse under this setting.
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This study proposes an approach for establishing an optimal multihop ad-hoc network using multiple unmanned aerial vehicles (UAVs) to provide emergency communication in disaster areas. The approach includes two stages, one uses particle swarm optimization (PSO) to find optimal positions to deploy UAVs, and the other uses a behavior-based controller to navigate the UAVs to their assigned positions without colliding with obstacles in an unknown environment. Several constraints related to the UAVs' sensing and communication ranges have been imposed to ensure the applicability of the proposed approach in real-world scenarios. A number of simulation experiments with data loaded from real environments have been conducted. The results show that our proposed approach is not only successful in establishing multihop ad-hoc routes but also meets the requirements for real-time deployment of UAVs.
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We introduce an approach for the answer-aware question generation problem. Instead of only relying on the capability of strong pre-trained language models, we observe that the information of answers and questions can be found in some relevant sentences in the context. Based on that, we design a model which includes two modules: a selector and a generator. The selector forces the model to more focus on relevant sentences regarding an answer to provide implicit local information. The generator generates questions by implicitly combining local information from the selector and global information from the whole context encoded by the encoder. The model is trained jointly to take advantage of latent interactions between the two modules. Experimental results on two benchmark datasets show that our model is better than strong pre-trained models for the question generation task. The code is also available (shorturl.at/lV567).
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2048 is a single-player stochastic puzzle game. This intriguing and addictive game has been popular worldwide and has attracted researchers to develop game-playing programs. Due to its simplicity and complexity, 2048 has become an interesting and challenging platform for evaluating the effectiveness of machine learning methods. This dissertation conducts comprehensive research on reinforcement learning and computer game algorithms for 2048. First, this dissertation proposes optimistic temporal difference learning, which significantly improves the quality of learning by employing optimistic initialization to encourage exploration for 2048. Furthermore, based on this approach, a state-of-the-art program for 2048 is developed, which achieves the highest performance among all learning-based programs, namely an average score of 625377 points and a rate of 72% for reaching 32768-tiles. Second, this dissertation investigates several techniques related to 2048, including the n-tuple network ensemble learning, Monte Carlo tree search, and deep reinforcement learning. These techniques are promising for further improving the performance of the current state-of-the-art program. Finally, this dissertation discusses pedagogical applications related to 2048 by proposing course designs and summarizing the teaching experience. The proposed course designs use 2048-like games as materials for beginners to learn reinforcement learning and computer game algorithms. The courses have been successfully applied to graduate-level students and received well by student feedback.
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