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基于局部像素嵌入的人脸图像超分辨率重构 被引量:1
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作者 胡宇 沈庭芝 +1 位作者 刘朋樟 赵三元 《北京理工大学学报》 EI CAS CSCD 北大核心 2011年第2期201-205,共5页
利用像素点在邻域空间的线性嵌入关系作为先验约束来重构高分辨率(HR)人脸图像.算法从HR训练样本集中选择与输入人脸最相近的K个样本进行配准,并以配准后的样本作为参考,学习目标图像中像素点的局部嵌入系数.在学习过程中,算法通过自适... 利用像素点在邻域空间的线性嵌入关系作为先验约束来重构高分辨率(HR)人脸图像.算法从HR训练样本集中选择与输入人脸最相近的K个样本进行配准,并以配准后的样本作为参考,学习目标图像中像素点的局部嵌入系数.在学习过程中,算法通过自适应调整各参考样本的权重来减小配准误差的影响,并利用总变差最小化约束嵌入系数的平滑度.结合局部像素嵌入关系以及降质模型,算法可以在最大后验估计的框架下实现对目标人脸的超分辨率重构.实验表明,重建的HR图像拥有更加细腻、清晰的局部特征,其平均峰值信噪比和结构相似度分别比对比算法高出1.26dB和0.04. 展开更多
关键词 超分辨率重构 局部像素嵌入 总变差最小化 人脸图像
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基于偏最小二乘的人脸超分辨率重构 被引量:1
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作者 胡宇 赵保军 +1 位作者 沈庭芝 刘朋樟 《北京理工大学学报》 EI CAS CSCD 北大核心 2010年第9期1098-1101,1130,共5页
提出了一种基于偏最小二乘(PLS)的超分辨率重构方法用于快速恢复高分辨率人脸图像.该算法利用主成分分析(PCA)方法将所有高、低分辨率人脸图像投影到各自的特征子空间中,通过PLS对高、低分辨率投影变量之间的统计关系进行回归建模.当输... 提出了一种基于偏最小二乘(PLS)的超分辨率重构方法用于快速恢复高分辨率人脸图像.该算法利用主成分分析(PCA)方法将所有高、低分辨率人脸图像投影到各自的特征子空间中,通过PLS对高、低分辨率投影变量之间的统计关系进行回归建模.当输入的低分辨率人脸图像给定时,对应的高分辨率人脸图像可以由训练后的回归模型导出.实验结果表明,在离线训练的情况下,所提出的算法可以快速地给出令人满意的重构解. 展开更多
关键词 偏最小二乘 特征投影 超分辨率人脸重构
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基于声卡的实时语音质量评价系统
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作者 刘文旭 沈庭芝 +1 位作者 田卉 刘朋樟 《电声技术》 2009年第11期60-63,67,共5页
针对目前语音质量评价系统成本高、设计复杂且不能实时评分,提出了基于声卡的实时评价系统。该系统以ITU-TP.862标准中的语音评价算法PESQ为核心,采用声卡作为语音播放和采集装置,利用多线程技术,以廉价的方式实现语音实时评分。并且,... 针对目前语音质量评价系统成本高、设计复杂且不能实时评分,提出了基于声卡的实时评价系统。该系统以ITU-TP.862标准中的语音评价算法PESQ为核心,采用声卡作为语音播放和采集装置,利用多线程技术,以廉价的方式实现语音实时评分。并且,以虚拟仪器Labwindows/CVI为平台,方便显示从PESQ算法中提出的语音参数。测试表明,该系统评分准确,可快速判断和分析语音设备的性能。 展开更多
关键词 PESQ 虚拟仪器 声卡 实时 多线程
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Novel algorithm for pose-invariant face recognition
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作者 刘朋樟 沈庭芝 +2 位作者 赵三元 岳雷 闫雪梅 《Journal of Beijing Institute of Technology》 EI CAS 2012年第2期246-252,共7页
By combining the AdaBoost modular locality preserving projection (AMLPP) algorithm and the locally linear regression (LLR) algorithm, a novel pose-invariant algorithm is proposed to realize high-accuracy face reco... By combining the AdaBoost modular locality preserving projection (AMLPP) algorithm and the locally linear regression (LLR) algorithm, a novel pose-invariant algorithm is proposed to realize high-accuracy face recognition under different poses. In the training stage of this algorithm, the AMLPP is employed to select the crucial frontal blocks and construct effective strong classifier. According to the selected frontal blocks and the corresponding non-frontal blocks, LLR is then applied to learn the linear mappings which will be used to convert the non-frontal blocks to visual frontal blocks. During the testing of the learned linear mappings, when a non-frontal face image is inputted, the non-frontal blocks corresponding to the selected frontal blocks are extracted and converted to the visual frontal blocks. The generated virtual frontal blocks are finally fed into the strong classifier constructed by AMLPP to realize accurate and efficient face recognition. Our algorithm is experimentally compared with other pose-invariant face recognition algorithms based on the Bosphorus database. The results show a significant improvement with our proposed algorithm. 展开更多
关键词 pose-invariant block-based virtual frontal view locally linear regression (LLR) FACERECOGNITION
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Face recognition using illuminant locality preserving projections
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作者 刘朋樟 沈庭芝 林健文 《Journal of Beijing Institute of Technology》 EI CAS 2011年第1期111-116,共6页
A novel supervised manifold learning method was proposed to realize high accuracy face recognition under varying illuminant conditions. The proposed method, named illuminant locality preserving projections (ILPP), e... A novel supervised manifold learning method was proposed to realize high accuracy face recognition under varying illuminant conditions. The proposed method, named illuminant locality preserving projections (ILPP), exploited illuminant directions to alleviate the effect of illumination variations on face recognition. The face images were first projected into low dimensional subspace, Then the ILPP translated the face images along specific direction to reduce lighting variations in the face. The ILPP reduced the distance between face images of the same class, while increase the dis tance between face images of different classes. This proposed method was derived from the locality preserving projections (LPP) methods, and was designed to handle face images with various illumi nations. It preserved the face image' s local structure in low dimensional subspace. The ILPP meth od was compared with LPP and discriminant locality preserving projections (DLPP), based on the YaleB face database. Experimental results showed the effectiveness of the proposed algorithm on the face recognition with various illuminations. 展开更多
关键词 locality preserving projections LPP illuminant direction illuminant locality preser ving projections (ILPP) face recognition
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Feature subset selection method for AdaBoost training
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作者 赵三元 沈庭芝 +2 位作者 孙晨升 刘朋樟 岳雷 《Journal of Beijing Institute of Technology》 EI CAS 2011年第3期399-402,共4页
The feature-selection problem in training AdaBoost classifiers is addressed in this paper. A working feature subset is generated by adopting a novel feature subset selection method based on the partial least square (... The feature-selection problem in training AdaBoost classifiers is addressed in this paper. A working feature subset is generated by adopting a novel feature subset selection method based on the partial least square (PLS) regression, and then trained and selected from this feature subset in Boosting. The experiments show that the proposed PLS-based feature-selection method outperforms the current feature ranking method and the random sampling method. 展开更多
关键词 dimensionality reduction Boosting method feature subset
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