Systems using numerous cameras are emerging in many fields due to their ease of production and reduced cost, and one of the fields where they are expected to be used more actively in the near future is in image-based ...Systems using numerous cameras are emerging in many fields due to their ease of production and reduced cost, and one of the fields where they are expected to be used more actively in the near future is in image-based rendering （IBR）. Color correction between views is necessary to use multi-view systems in IBR to make audiences feel comfortable when views are switched or when a free viewpoint video is displayed. Color correction usually involves two steps： the first is to adjust camera parameters such as gain, brightness, and aperture before capture, and the second is to modify captured videos through image processing. This paper deals with the latter, which does not need a color pattern board. The proposed method uses scale invariant feature transform （SIFT） to detect correspondences, treats RGB channels independently, calculates lookup tables with an energy-minimization approach, and corrects captured video with these tables. The experimental results reveal that this approach works well.展开更多
针对多视图立体网络在弱纹理或非朗伯曲面等挑战性区域重建效果差的问题,首先提出一个基于3个并行扩展卷积和注意力机制的多尺度特征提取模块,在增加感受野的同时捕获特征之间的依赖关系以获取全局上下文信息,从而提升多视图立体网络在...针对多视图立体网络在弱纹理或非朗伯曲面等挑战性区域重建效果差的问题,首先提出一个基于3个并行扩展卷积和注意力机制的多尺度特征提取模块,在增加感受野的同时捕获特征之间的依赖关系以获取全局上下文信息,从而提升多视图立体网络在挑战性区域特征的表征能力以进行鲁棒的特征匹配。其次在代价体正则化3D CNN部分引入注意力机制,使网络注意于代价体中的重要区域以进行平滑处理。另外建立一个神经渲染网络,该网络利用渲染参考损失精确地解析辐射场景表达的几何外观信息,并引入深度一致性损失保持多视图立体网络与神经渲染网络之间的几何一致性,有效地缓解有噪声代价体对多视图立体网络的不利影响。该算法在室内DTU数据集中测试,点云重建的完整性和整体性指标分别为0.289和0.326,与基准方法CasMVSNet相比,分别提升24.9%和8.2%,即使在挑战性区域也得到高质量的重建效果;在室外Tanks and Temples中级数据集中,点云重建的平均F-score为60.31,与方法UCS-Net相比提升9.9%,体现出较强的泛化能力。展开更多
In this paper we deal with Twitter and the presence of the keyword “Macedonia” in tweets over a period of time. We searched for the same term in three different languages, i.e. “Μακεδονíα”, “Macedoni...In this paper we deal with Twitter and the presence of the keyword “Macedonia” in tweets over a period of time. We searched for the same term in three different languages, i.e. “Μακεδονíα”, “Macedonia” and “Македонска - Македониjа”, since we are primarily interested in views from Greece and FYROM without excluding views from other regions. We use methods from Social Network Analysis (SNA) in order to create networks of users, calculate some main network metrics, measure user importance and investigate the presence of possible fragmentations—communities among them. We furthermore proceed to a form of content analysis, using pairs of words within tweets, in order to obtain main ideas, trends and public views that circulated over the network.展开更多
针对在基于深度学习技术的特征提取网络中,深层次的卷积神经网络提取的特征缺乏低级语义信息的问题,该文提出了语义增强的多视立体视觉方法。首先,提出了一种ConvLSTM(Convolutional Long Short-Term Memory)语义聚合网络,通过使用ConvL...针对在基于深度学习技术的特征提取网络中,深层次的卷积神经网络提取的特征缺乏低级语义信息的问题,该文提出了语义增强的多视立体视觉方法。首先,提出了一种ConvLSTM(Convolutional Long Short-Term Memory)语义聚合网络,通过使用ConvLSTM网络结构,对多个卷积层提取的特征图进行预测,得到融合每层语义信息的特征图,有助于在空间上层层抽取图像的高级特征时,利用长短期记忆神经网络结构的记忆功能来增强高层特征图中的低级语义信息,提高了弱纹理区域的重建效果,提高了3D重建的鲁棒性和完整性;其次,提出了一种可见性网络,在灰度图的基础上,通过突出特征图上可见区域的特征,加深了可见区域在特征图中的影响,有助于提高三维重建效果;最后,提取图像的纹理信息,并进入ConvLSTM语义聚合网络提取深层次特征,提高了弱纹理区域的重建效果。与主流的多视立体视觉重建方法相比,重建效果较好。展开更多
文摘Systems using numerous cameras are emerging in many fields due to their ease of production and reduced cost, and one of the fields where they are expected to be used more actively in the near future is in image-based rendering （IBR）. Color correction between views is necessary to use multi-view systems in IBR to make audiences feel comfortable when views are switched or when a free viewpoint video is displayed. Color correction usually involves two steps： the first is to adjust camera parameters such as gain, brightness, and aperture before capture, and the second is to modify captured videos through image processing. This paper deals with the latter, which does not need a color pattern board. The proposed method uses scale invariant feature transform （SIFT） to detect correspondences, treats RGB channels independently, calculates lookup tables with an energy-minimization approach, and corrects captured video with these tables. The experimental results reveal that this approach works well.
文摘针对多视图立体网络在弱纹理或非朗伯曲面等挑战性区域重建效果差的问题,首先提出一个基于3个并行扩展卷积和注意力机制的多尺度特征提取模块,在增加感受野的同时捕获特征之间的依赖关系以获取全局上下文信息,从而提升多视图立体网络在挑战性区域特征的表征能力以进行鲁棒的特征匹配。其次在代价体正则化3D CNN部分引入注意力机制,使网络注意于代价体中的重要区域以进行平滑处理。另外建立一个神经渲染网络,该网络利用渲染参考损失精确地解析辐射场景表达的几何外观信息,并引入深度一致性损失保持多视图立体网络与神经渲染网络之间的几何一致性,有效地缓解有噪声代价体对多视图立体网络的不利影响。该算法在室内DTU数据集中测试,点云重建的完整性和整体性指标分别为0.289和0.326,与基准方法CasMVSNet相比,分别提升24.9%和8.2%,即使在挑战性区域也得到高质量的重建效果;在室外Tanks and Temples中级数据集中,点云重建的平均F-score为60.31,与方法UCS-Net相比提升9.9%,体现出较强的泛化能力。
文摘In this paper we deal with Twitter and the presence of the keyword “Macedonia” in tweets over a period of time. We searched for the same term in three different languages, i.e. “Μακεδονíα”, “Macedonia” and “Македонска - Македониjа”, since we are primarily interested in views from Greece and FYROM without excluding views from other regions. We use methods from Social Network Analysis (SNA) in order to create networks of users, calculate some main network metrics, measure user importance and investigate the presence of possible fragmentations—communities among them. We furthermore proceed to a form of content analysis, using pairs of words within tweets, in order to obtain main ideas, trends and public views that circulated over the network.
文摘针对在基于深度学习技术的特征提取网络中,深层次的卷积神经网络提取的特征缺乏低级语义信息的问题,该文提出了语义增强的多视立体视觉方法。首先,提出了一种ConvLSTM(Convolutional Long Short-Term Memory)语义聚合网络,通过使用ConvLSTM网络结构,对多个卷积层提取的特征图进行预测,得到融合每层语义信息的特征图,有助于在空间上层层抽取图像的高级特征时,利用长短期记忆神经网络结构的记忆功能来增强高层特征图中的低级语义信息,提高了弱纹理区域的重建效果,提高了3D重建的鲁棒性和完整性;其次,提出了一种可见性网络,在灰度图的基础上,通过突出特征图上可见区域的特征,加深了可见区域在特征图中的影响,有助于提高三维重建效果;最后,提取图像的纹理信息,并进入ConvLSTM语义聚合网络提取深层次特征,提高了弱纹理区域的重建效果。与主流的多视立体视觉重建方法相比,重建效果较好。
