This paper introduces a learned hierarchical B-frame coding scheme in response to the Grand Challenge on Neural Network-based Video Coding at ISCAS 2023. We address specifically three issues, including (1) B-frame coding, (2) YUV 4:2:0 coding, and (3) content-adaptive variable-rate coding with only one single model. Most learned video codecs operate internally in the RGB domain for P-frame coding. B-frame coding for YUV 4:2:0 content is largely under-explored. In addition, while there have been prior works on variable-rate coding with conditional convolution, most of them fail to consider the content information. We build our scheme on conditional augmented normalized flows (CANF). It features conditional motion and inter-frame codecs for efficient B-frame coding. To cope with YUV 4:2:0 content, two conditional inter-frame codecs are used to process the Y and UV components separately, with the coding of the UV components conditioned additionally on the Y component. Moreover, we introduce adaptive feature modulation in every convolutional layer, taking into account both the content information and the coding levels of B-frames to achieve content-adaptive variable-rate coding. Experimental results show that our model outperforms x265 and the winner of last year's challenge on commonly used datasets in terms of PSNR-YUV.
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One of the key challenges in deploying RL to real-world applications is to adapt to variations of unknown environment contexts, such as changing terrains in robotic tasks and fluctuated bandwidth in congestion control. Existing works on adaptation to unknown environment contexts either assume the contexts are the same for the whole episode or assume the context variables are Markovian. However, in many real-world applications, the environment context usually stays stable for a stochastic period and then changes in an abrupt and unpredictable manner within an episode, resulting in a segment structure, which existing works fail to address. To leverage the segment structure of piecewise stable context in real-world applications, in this paper, we propose a \textit{\textbf{Se}gmented \textbf{C}ontext \textbf{B}elief \textbf{A}ugmented \textbf{D}eep~(SeCBAD)} RL method. Our method can jointly infer the belief distribution over latent context with the posterior over segment length and perform more accurate belief context inference with observed data within the current context segment. The inferred belief context can be leveraged to augment the state, leading to a policy that can adapt to abrupt variations in context. We demonstrate empirically that SeCBAD can infer context segment length accurately and outperform existing methods on a toy grid world environment and Mujuco tasks with piecewise-stable context.
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Weakly-supervised learning (WSL) has been proposed to alleviate the conflict between data annotation cost and model performance through employing sparsely-grained (i.e., point-, box-, scribble-wise) supervision and has shown promising performance, particularly in the image segmentation field. However, it is still a very challenging problem due to the limited supervision, especially when only a small number of labeled samples are available. Additionally, almost all existing WSL segmentation methods are designed for star-convex structures which are very different from curvilinear structures such as vessels and nerves. In this paper, we propose a novel sparsely annotated segmentation framework for curvilinear structures, named YoloCurvSeg, based on image synthesis. A background generator delivers image backgrounds that closely match real distributions through inpainting dilated skeletons. The extracted backgrounds are then combined with randomly emulated curves generated by a Space Colonization Algorithm-based foreground generator and through a multilayer patch-wise contrastive learning synthesizer. In this way, a synthetic dataset with both images and curve segmentation labels is obtained, at the cost of only one or a few noisy skeleton annotations. Finally, a segmenter is trained with the generated dataset and possibly an unlabeled dataset. The proposed YoloCurvSeg is evaluated on four publicly available datasets (OCTA500, CORN, DRIVE and CHASEDB1) and the results show that YoloCurvSeg outperforms state-of-the-art WSL segmentation methods by large margins. With only one noisy skeleton annotation (respectively 0.14%, 0.02%, 1.4%, and 0.65% of the full annotation), YoloCurvSeg achieves more than 97% of the fully-supervised performance on each dataset. Code and datasets will be released at https://github.com/llmir/YoloCurvSeg.
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Interoperability issue is a significant problem in Building Information Modeling (BIM). Object type, as a kind of critical semantic information needed in multiple BIM applications like scan-to-BIM and code compliance checking, also suffers when exchanging BIM data or creating models using software of other domains. It can be supplemented using deep learning. Current deep learning methods mainly learn from the shape information of BIM objects for classification, leaving relational information inherent in the BIM context unused. To address this issue, we introduce a two-branch geometric-relational deep learning framework. It boosts previous geometric classification methods with relational information. We also present a BIM object dataset IFCNet++, which contains both geometric and relational information about the objects. Experiments show that our framework can be flexibly adapted to different geometric methods. And relational features do act as a bonus to general geometric learning methods, obviously improving their classification performance, thus reducing the manual labor of checking models and improving the practical value of enriched BIM models.
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3D车道检测是自动驾驶系统的组成部分。以前的CNN和基于变压器的方法通常首先从前视图图像中生成鸟类视图(BEV)特征映射,然后使用带有BEV功能映射的子网络作为输入来预测3D车道。这种方法需要在BEV和前视图之间进行明确的视图转换,这本身仍然是一个具有挑战性的问题。在本文中,我们提出了一种基于单阶段变压器的方法,该方法直接计算3D车道参数并可以规避困难的视图变换步骤。具体而言,我们通过使用曲线查询来将3D车道检测作为曲线传播问题。 3D车道查询由动态和有序的锚点集表示。通过这种方式,在变压器解码器迭代中具有曲线表示的查询可完善3D车道检测结果。此外,引入了曲线交叉意见模块,以计算曲线查询和图像特征之间的相似性。此外,提供了可以捕获曲线查询更多相对图像特征的上下文采样模块,以进一步提高3D车道检测性能。我们评估了合成数据集和现实数据集的3D车道检测方法,实验结果表明,与最先进的方法相比,我们的方法实现了有希望的性能。每个组件的有效性也通过消融研究验证。
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提出了基于视觉变压器(VLT)的新型场景文本识别器。受NLP领域的Levenshtein Transformer的启发,提出的方法(命名为Levenshtein OCR和Short Levocr)探索了一种自动从裁剪自然图像中自动转录文本内容的替代方法。具体而言,我们将场景文本识别的问题视为迭代序列完善过程。由纯视觉模型产生的初始预测序列被编码并馈送到跨模式变压器中,以与视觉特征相互作用并融合,以逐渐近似地面真理。改进过程是通过两个基本字符级操作完成的:删除和插入,它们是通过模仿学习来学习的,并允许并行解码,动态长度变化和良好的解释性。定量实验清楚地表明,Levocr在标准基准上实现最新性能,定性分析验证了拟议的Levocr算法的有效性和优势。代码将很快发布。
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多年来,场景文本识别(STR)一直是计算机视觉的积极研究主题。为了解决这个具有挑战性的问题,已经提出了许多创新的方法,并将语言知识纳入STR模型最近已成为一个显着的趋势。在这项工作中,我们首先从视觉变压器(VIT)的最新进展中汲取灵感来构建一个概念上简单而强大的视觉str模型,该模型建立在VIT和胜过以前的现场文本识别的先前最新模型,包括纯视觉模型和语言增强方法。为了整合语言知识,我们进一步提出了一种多粒性预测策略,以隐式方式将信息从语言模式注入模型,即NLP中广泛使用的子字表示(BPE和Wordpiece)被引入输出空间,除了传统的字符级别表示外,不采用独立语言模型(LM)。所得的算法(称为MGP-STR)能够将Str的性能包络提高到更高的水平。具体而言,它的平均识别精度在标准基准上达到93.35%。代码将很快发布。
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在前景点(即物体)和室外激光雷达点云中的背景点之间通常存在巨大的失衡。它阻碍了尖端的探测器专注于提供信息的区域,以产生准确的3D对象检测结果。本文提出了一个新的对象检测网络,该对象检测网络通过称为PV-RCNN ++的语义点 - 素voxel特征相互作用。与大多数现有方法不同,PV-RCNN ++探索了语义信息,以增强对象检测的质量。首先,提出了一个语义分割模块,以保留更具歧视性的前景关键。这样的模块将指导我们的PV-RCNN ++在关键区域集成了更多与对象相关的点和体素特征。然后,为了使点和体素有效相互作用,我们利用基于曼哈顿距离的体素查询来快速采样关键点周围的体素特征。与球查询相比,这种体素查询将降低从O(N)到O(K)的时间复杂性。此外,为了避免仅学习本地特征,基于注意力的残留点网模块旨在扩展接收场,以将相邻的素素特征适应到关键点中。 Kitti数据集的广泛实验表明,PV-RCNN ++达到81.60 $ \%$,40.18 $ \%$,68.21 $ \%$ \%$ 3D地图在汽车,行人和骑自行车的人方面,可以在州,甚至可以在州立骑行者,甚至更好地绩效-艺术。
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昼夜节律的破坏是阿尔茨海默氏病(AD)患者的基本症状。人类脑中基因表达的完整昼夜节律编排及其与AD的固有关联仍然很大程度上是未知的。我们提出了一种新颖的综合方法,即Prime,以检测和分析在多个数据集中不合时宜的高维基因表达数据中的节奏振荡模式。为了证明Prime的实用性,首先,我们通过从小鼠肝脏中的时间课程表达数据集作为跨物种和跨器官验证来对其进行验证。然后,我们将其应用于研究来自19个对照和AD患者的19个人脑区域的未接收基因组基因表达中的振荡模式。我们的发现揭示了15对控制大脑区域中清晰,同步的振荡模式,而这些振荡模式要么消失或昏暗。值得注意的是,Prime在不需要样品的时间戳而发现昼夜节律的节奏模式。 Prime的代码以及在本文中复制数字的代码,可在https://github.com/xinxingwu-uk/prime上获得。
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本文回顾了AIM 2022上压缩图像和视频超级分辨率的挑战。这项挑战包括两条曲目。轨道1的目标是压缩图像的超分辨率,轨迹〜2靶向压缩视频的超分辨率。在轨道1中,我们使用流行的数据集DIV2K作为培训,验证和测试集。在轨道2中,我们提出了LDV 3.0数据集,其中包含365个视频,包括LDV 2.0数据集(335个视频)和30个其他视频。在这一挑战中,有12支球队和2支球队分别提交了赛道1和赛道2的最终结果。所提出的方法和解决方案衡量了压缩图像和视频上超分辨率的最先进。提出的LDV 3.0数据集可在https://github.com/renyang-home/ldv_dataset上找到。此挑战的首页是在https://github.com/renyang-home/aim22_compresssr。
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