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面向RGB-D图像的多层特征提取算法综述

中国图象图形学报 2024年第5期29卷 1346-1363页

作者：李洋吴晓群北京工商大学计算机学院北京100048 食品安全大数据技术北京市重点实验室北京100048

RGB-D图像包含丰富的多层特征,如底层的线特征、平面特征,高层的语义特征,面向RGB-D图像的多层特征提取结果可以作为先验知识提升室内场景重建、SLAM(simultaneous localization and mapping)等多种任务的输出质量,是计算机图形学领域... 详细信息

RGB-D图像包含丰富的多层特征,如底层的线特征、平面特征,高层的语义特征,面向RGB-D图像的多层特征提取结果可以作为先验知识提升室内场景重建、SLAM(simultaneous localization and mapping)等多种任务的输出质量,是计算机图形学领域的热点研究内容之一。传统的多层特征提取算法一般利用RGB图像中丰富的颜色、纹理信息以及深度图像中的几何信息提取多层特征,此类提取算法依赖输入RGB-D图像的质量,而受采集过程中环境和人为因素的影响,很难得到高质量的RGB-D图像。随着深度学习技术的快速发展,基于深度学习的多层特征提取算法突破了这一限制,涌现出一批高质量的研究成果。本文对面向RGB-D图像的多层特征提取算法进行综述。首先,汇总了现有的常用于多层特征提取任务的RGB-D数据集和相关算法的质量评价指标。然后,按照特征所处的不同层次,依次对线、平面和语义特征相关算法进行了总结。此外,本文还对各算法的优缺点进行比较并结合常用算法质量评价标准进行了定量分析。最后,讨论了当前多层特征提取算法亟待解决的问题并展望了未来发展的趋势。

关键词： RGB-D图像多层特征线特征平面特征语义特征特征提取

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三维重建场景的纹理优化算法综述

中国图象图形学报 2024年第8期29卷 2303-2318页

作者：于柳吴晓群北京工商大学计算机与人工智能学院北京100048 食品安全大数据技术北京市重点实验室北京100048

三维重建场景的纹理优化是计算机图形学和计算机视觉等领域的基础任务之一,其目的是优化纹理映射,减小重建几何体和纹理之间的对齐误差,提升重建场景的细节表现。为了对三维重建场景纹理优化算法的现状进行全面研究,本文从传统优化算法... 详细信息

三维重建场景的纹理优化是计算机图形学和计算机视觉等领域的基础任务之一,其目的是优化纹理映射,减小重建几何体和纹理之间的对齐误差,提升重建场景的细节表现。为了对三维重建场景纹理优化算法的现状进行全面研究,本文从传统优化算法和基于深度学习的优化算法两个方面对现有三维重建场景的纹理优化算法进行综述。传统的纹理优化算法一般通过优化相机姿态、校正图像颜色、提高重建几何精度等步骤达到三维场景纹理优化的目的,按照优化方式的不同,主要包括基于图像融合的优化算法、基于图像拼接的优化算法以及纹理与几何联合优化算法,而基于深度学习的优化算法则利用神经网络优化三维场景纹理。同时,本文汇总了常用的三维重建场景纹理优化的数据集与评价指标,并重点讨论了不同数据集和评价指标的特点与用法。此外,本文对现有的各类纹理优化算法进行了定性分析和定量对比,重点阐述了这些算法的原理及优缺点,最后探讨了三维重建场景的纹理优化面临的挑战和发展方向。

关键词：场景重建纹理优化图像融合图像拼接联合优化

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基于结构引导边界增长的大孔洞深度补全算法

图学学报 2024年第3期45卷 548-557页

作者：赵盛吴晓群刘鑫北京工商大学计算机与人工智能学院北京100048 食品安全大数据技术北京市重点实验室北京100048

使用消费级深度相机采集深度信息时,受到设备、环境和物体材质等因素的影响,采集的深度信息往往存在缺失和孔洞,使得深度图像在后续的视觉任务中应用受限。现有的深度补全算法在解决大面积深度缺失时存在补全效果不佳和物体边界保持较... 详细信息

使用消费级深度相机采集深度信息时,受到设备、环境和物体材质等因素的影响,采集的深度信息往往存在缺失和孔洞,使得深度图像在后续的视觉任务中应用受限。现有的深度补全算法在解决大面积深度缺失时存在补全效果不佳和物体边界保持较差的问题。针对这2个问题,提出了基于结构引导边界增长的大孔洞深度补全算法。首先,结合RGB图像提供的边界信息,利用结构引导的边界增长策略补全物体边界处的深度缺失;最后,利用大孔洞切分填充与均值滤波相结合的方法,补全物体内部的大孔洞。实验结果表明,该算法能够在具有大面积缺失以及跨越物体缺失情况下有效地保持物体边界,同时能够补全大面积缺失的深度信息,并在多个数据集上的定量以及定性结果证明了该方法的有效性。

关键词：分割图像结构引导 Bézier曲线拟合大孔洞补全边界增长

Pinning Synchronization of Discrete-Time Complex Networks with Different Time-Varying Delays

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Journal of Systems Science & Complexity 2019年第6期32卷 1560-1571页

作者： ZHANG Qunjiao wu xiaoqun LIU Jie School of Mathematics and Computer Wuhan Textile UniversityWuhan 430073China School of Mathematics and Statistics Wuhan UniversityWuhan 430072China

This paper investigates pinning synchronization of discrete-time complex networks with differen t time-varying *** important lemma is presen ted and proved,t hen detailed analysis is given to yield some synchronization criteria for this kind of net *** results provide an effective way to synchronize discrete-time complex networks by reducing control ***,these theoretical results are illustrated by a complex network via two kinds of pinning *** simulations verify the feasibil计y of the proposed methods.

关键词： Different time-varying delays discrete・time complex networks pinning synchronization

BIDIRECTIONALLY COUPLED SYNCHRONIZATION OF THE GENERALIZED LORENZ SYSTEMS

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Journal of Systems Science & Complexity 2011年第3期24卷 433-448页

作者： Juan CHEN Jun-an LU xiaoqun wu School of Mathematics and Statistics Wuhan University Wuhan 430072 China

wu, Chen, and Cai （2007） investigated chaos synchronization of two identical generalized Lorenz systems unidirectionally coupled by a linear state error feedback controller. However, bidirec- tional coupling in real life such as complex dynamical networks is more universal. This paper provides a unified method for analyzing chaos synchronization of two bidirectionally coupled generalized Lorenz systems. Some sufficient synchronization conditions for some special coupling matrices （diagonal ma- trices, so-called dislocated coupling matrices, and so on） are derived through rigorously mathematical theory. In particular, for the classical Lorenz system, the authors obtain synchronization criteria which only depend upon its parameters using new estimation of the ultimate bounds of Lorenz system （Chaos, Solitons, and Fractals, 2005）. The criteria are then applied to four typical generalized Lorenz systems in the numerical simulations for verification.

关键词： Bidirectionally-coupled chaos generalized lorenz system synchronization ultimate bound.

The Rites of Mourning in Archaic and Classical Greece and in Pre-Qin China

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Fudan Journal of the Humanities and Social Sciences 2015年第2期8卷 235-270页

作者： xiaoqun wu Department of History Fudan University 220 Handan Road Shanghai 200433 Chinae-mail: xqwu@ ***

This article attempts to compare the mourning of the dead before burial in Archaic and Classical Greece with that in Pre-Qin China. It focuses on three main subjects of mourning before burial--lamentation, mourners＇ gestures and behaviors, and mourning apparel--to demonstrate the cultural function and social influence of the mourning rituals through the analysis of the function and purpose of the mourning of two ancient peoples. We find that there are some differences in these two ancient societies, although the rites of mourning share some basic and similar procedures and functions.

关键词： Archaic and Classical Greece Pre-Qin China Mourning apparel Lamentation Mourners' gestures and behaviors Cultural function

Variational reconstruction using subdivision surfaces with continuous sharpness control

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Computational Visual Media 2017年第3期3卷 217-228页

作者： xiaoqun wu Jianmin Zheng Yiyu Cai Haisheng Li Beijing Key Lab of Big Data Technology for Food Safety School of Computer and Information EngineeringBeijing Technology and Business University College of Engineering Nanyang Technological University

We present a variational method for subdivision surface reconstruction from a noisy dense mesh. A new set of subdivision rules with continuous sharpness control is introduced into Loop subdivision for better modeling subdivision surface features such as semi-sharp creases, creases, and corners. The key idea is to assign a sharpness value to each edge of the control mesh to continuously control the surface *** on the new subdivision rules, a variational model with L_1 norm is formulated to find the control mesh and the corresponding sharpness values of the subdivision surface that best fits the input mesh. An iterative solver based on the augmented Lagrangian method and particle swarm optimization is used to solve the resulting non-linear, non-differentiable optimization problem. Our experimental results show that our method can handle meshes well with sharp/semi-sharp features and noise.

关键词： variational model subdivision surface sharpness surface reconstruction L1 norm

Synchronizability of time-varying structured duplex dynamical networks with different intra-layer rewiring mechanisms

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Science China(Technological Sciences) 2022年第2期65卷 375-385页

作者： wu xiaoqun ZHOU Xiong LIU Jie YANG QiRui CHEN Yuan Yuan School of Mathematics and Statistics Wuhan UniversityWuhan 430072China Hubei Key Laboratory of Computational Science Wuhan UniversityWuhan 430072China Research Centre of Nonlinear Science Wuhan Textile UniversityWuhan 430073China School of Journalism and Communication Hubei University of EconomicsWuhan 430205China

Global synchronizability of duplex networks induced by three different intra-layer rewiring mechanisms is explored in this *** rewiring mechanisms are named as model-preserving rewiring(MPR), simply direct rewiring(SDR), and degree-preserving rewiring(DPR), respectively. It is found that high switching frequencies will certainly enhance global synchronizability for WSWS duplex networks(i.e., each layer is independently formed by the algorithm proposed by Watts and Strogatz for generating small-world networks), ER-ER duplex networks(i.e., each layer is independently generated by the algorithm proposed by Erd ¨os and Renyi) and BA-BA duplex networks(i.e., each layer is independently formed by the classical BA algorithm). Namely,the faster the intra-layer couplings are reconnected, the faster the duplex networks reach global synchronization. Furthermore,we find that by increasing the intra-or inter-coupling strengths, the WS-WS time-varying network’s global synchronizability is enhanced. Take the WS-WS time-varying network as an example, we find that SDR mechanism has greater impact on global synchronizability than MPR mechanism and DPR mechanism. The related dynamical networks can arrive at synchronization faster by SDR than by MPR or DPR. Thus, we only study the effects of SDR on ER-ER duplex networks and BA-BA duplex networks. In addition, we obtain the fact via numerical simulations that, switching intra-layer coupling topologies under SDR mechanism has the greatest impact on the BA-BA duplex network, followed by the ER-ER network, and has the weakest influence on the WS-WS duplex network in terms of improving the global synchronizability when all the intra-layer networks are sparse and have the same average degree. Finally, the global synchronizability of WS-WS and BA-BA time-varying networks is improved compared with static duplex networks, the reason being that the networks tend to be randomized under SDR according to analysis of the networks’ average clus

关键词： multiplex network time-varying networks intra-layer connection synchronizability reconnection

Topology inference of uncertain complex dynamical networks and its applications in hidden nodes detection

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Science China(Technological Sciences) 2016年第8期59卷 1232-1243页

作者： WANG YingFei wu xiaoqun FENG Hui LU JunAn LU JinHu School of Mathematics and Statistics Wuhan University Wuhan 430072 China Computational Science Hubei Key Laboratory Wuhan University Wuhan 430072 China Academy of Mathematics and Systems Science Chinese Academy of Sciences Beijing 100190 China

The topological structure of a complex dynamical network plays a vital role in determining the network＇s evolutionary mecha- nisms and functional behaviors, thus recognizing and inferring the network structure is of both theoretical and practical signif- icance. Although various approaches have been proposed to estimate network topologies, many are not well established to the noisy nature of network dynamics and ubiquity of transmission delay among network individuals. This paper focuses on to- pology inference of uncertain complex dynamical networks. An auxiliary network is constructed and an adaptive scheme is proposed to track topological parameters. It is noteworthy that the considered network model is supposed to contain practical stochastic perturbations, and noisy observations are taken as control inputs of the constructed auxiliary network. In particular, the control technique can be further employed to locate hidden sources （or latent variables） in networks. Numerical examples are provided to illustrate the effectiveness of the proposed scheme. In addition, the impact of coupling strength and coupling delay on identification performance is assessed. The proposed scheme provides engineers with a convenient approach to infer topologies of general complex dynamical networks and locate hidden sources, and the detailed performance evaluation can further facilitate practical circuit design.

关键词： complex dynamical network topology inference coupling delay stochastic perturbation hidden node