A face recognition scheme is proposed, wherein a face image is preprocessed by pixel averaging and energy normalizing to reduce data dimension and brightness variation effect, followed by the Fourier transform to esti...A face recognition scheme is proposed, wherein a face image is preprocessed by pixel averaging and energy normalizing to reduce data dimension and brightness variation effect, followed by the Fourier transform to estimate the spectrum of the preprocessed image. The principal component analysis is conducted on the spectra of a face image to obtain eigen features. Combining eigen features with a Parzen classifier, experiments are taken on the ORL face database.展开更多
With the development of seismic exploration,passive-source seismic data has attracted increasing attention.Ambient noise passive seismic sources exists widely in nature and industrial production.Passive seismic data i...With the development of seismic exploration,passive-source seismic data has attracted increasing attention.Ambient noise passive seismic sources exists widely in nature and industrial production.Passive seismic data is important in logging while drilling(LWD),large-scale structural exploration,etc.In this paper,we proposed a passive multiple reverse time migration imaging(PMRTMI)method based on wavefield decomposition and normalized imaging conditions method.This method differs from seismic interferometry in that it can use raw passive seismic data directly in RTM imaging without reconstruction of virtual active gather,and we use the wavefield decomposition method to eliminate the low frequency noise in RTM.Further,the energy normalized imaging condition is used in full wavefield decomposition,which can not only enhance the image quality of both edge and deep information but also overcome the wrong energy problem caused by uneven distribution of passive sources;furthermore,this method exhibits high efficiency.Finally,numerical examples with the Marmousi model show the effectiveness of the method.展开更多
Projectile perforation of concrete slabs will produce numerous concrete fragments on the rear face of the concrete slabs. These concrete fragments will cause serious secondary damage to the indoor personnel and equipm...Projectile perforation of concrete slabs will produce numerous concrete fragments on the rear face of the concrete slabs. These concrete fragments will cause serious secondary damage to the indoor personnel and equipment of protective structures.Accurately evaluating the damage area of concrete slabs is an important problem. Therefore, a theoretical model of a rigid projectile perforation of concrete slabs is constructed using the energy method in this paper. In this model, a new shear failure method is proposed to calculate the energy consumption of the shear formation by combining with the von-Mises failure criterion and failure strain. Based on the energy conservation and principle of minimum potential energy, explicit equations for the perforation performance are formulated. The theoretical predictions agree well with the experimental results. Furthermore,experiments on a high-speed projectile normal perforation of concrete are carried out to verify the accuracy of the corresponding theoretical prediction.展开更多
In this paper, we propose a novel method of cleaning up facial imperfections such as bumps and blemishes that may detract from a pleasing digital portrait. Contrasting with traditional methods which tend to blur facia...In this paper, we propose a novel method of cleaning up facial imperfections such as bumps and blemishes that may detract from a pleasing digital portrait. Contrasting with traditional methods which tend to blur facial details, our method fully retains fine scale skin textures (pores etc.) of the subject. Our key idea is to find a quantity, namely normalized local energy, to capture different characteristics of fine scale details and distractions, based on empirical mode decomposition, and then build a quantitative measurement of facial skin appearance which characterizes both imperfections and facial details in a unified framework. Finally, we use the quantitative measurement as a guide to enhance facial skin. We also introduce a few high-level, intuitive parameters for controlling the amount of enhancement. In addition, an adaptive local mean and neighborhood limited empirical mode decomposition algorithm is also developed to improve in two respects the performance of empirical mode decomposition. It can effectively avoid the gray spots effect commonly associated with traditional empirical mode decomposition when dealing with high-nonstationary images.展开更多
Given graphs Gand G, we define a graph operation on Gand G,namely the SSG-vertex join of Gand G, denoted by G★ G. Let S(G) be the subdivision graph of G. The SSG-vertex join G★Gis the graph obtained from S(G) and S(...Given graphs Gand G, we define a graph operation on Gand G,namely the SSG-vertex join of Gand G, denoted by G★ G. Let S(G) be the subdivision graph of G. The SSG-vertex join G★Gis the graph obtained from S(G) and S(G) by joining each vertex of Gwith each vertex of G. In this paper, when G(i = 1, 2) is a regular graph, we determine the normalized Laplacian spectrum of G★ G. As applications, we construct many pairs of normalized Laplacian cospectral graphs, the normalized Laplacian energy, and the degree Kirchhoff index of G★G.展开更多
文摘A face recognition scheme is proposed, wherein a face image is preprocessed by pixel averaging and energy normalizing to reduce data dimension and brightness variation effect, followed by the Fourier transform to estimate the spectrum of the preprocessed image. The principal component analysis is conducted on the spectra of a face image to obtain eigen features. Combining eigen features with a Parzen classifier, experiments are taken on the ORL face database.
基金sponsored by the Natural Science Foundation of China(No.41874139)the Natural Science Foundation of China(No.41674124)Jilin Province Foundation for Excellent Youths(No.20190103139JH)
文摘With the development of seismic exploration,passive-source seismic data has attracted increasing attention.Ambient noise passive seismic sources exists widely in nature and industrial production.Passive seismic data is important in logging while drilling(LWD),large-scale structural exploration,etc.In this paper,we proposed a passive multiple reverse time migration imaging(PMRTMI)method based on wavefield decomposition and normalized imaging conditions method.This method differs from seismic interferometry in that it can use raw passive seismic data directly in RTM imaging without reconstruction of virtual active gather,and we use the wavefield decomposition method to eliminate the low frequency noise in RTM.Further,the energy normalized imaging condition is used in full wavefield decomposition,which can not only enhance the image quality of both edge and deep information but also overcome the wrong energy problem caused by uneven distribution of passive sources;furthermore,this method exhibits high efficiency.Finally,numerical examples with the Marmousi model show the effectiveness of the method.
基金supported by the National Natural Science Foundation of China(Grant Nos.11390362&11521062)
文摘Projectile perforation of concrete slabs will produce numerous concrete fragments on the rear face of the concrete slabs. These concrete fragments will cause serious secondary damage to the indoor personnel and equipment of protective structures.Accurately evaluating the damage area of concrete slabs is an important problem. Therefore, a theoretical model of a rigid projectile perforation of concrete slabs is constructed using the energy method in this paper. In this model, a new shear failure method is proposed to calculate the energy consumption of the shear formation by combining with the von-Mises failure criterion and failure strain. Based on the energy conservation and principle of minimum potential energy, explicit equations for the perforation performance are formulated. The theoretical predictions agree well with the experimental results. Furthermore,experiments on a high-speed projectile normal perforation of concrete are carried out to verify the accuracy of the corresponding theoretical prediction.
基金supported by the National Natural Science Foundation of China under Grant Nos.60403038 and 60703084the NaturalScience Foundation of Jiangsu Province under Grant No.BK2007571the Natural Science Foundation of Liaoning Province under Grant No.20082176
文摘In this paper, we propose a novel method of cleaning up facial imperfections such as bumps and blemishes that may detract from a pleasing digital portrait. Contrasting with traditional methods which tend to blur facial details, our method fully retains fine scale skin textures (pores etc.) of the subject. Our key idea is to find a quantity, namely normalized local energy, to capture different characteristics of fine scale details and distractions, based on empirical mode decomposition, and then build a quantitative measurement of facial skin appearance which characterizes both imperfections and facial details in a unified framework. Finally, we use the quantitative measurement as a guide to enhance facial skin. We also introduce a few high-level, intuitive parameters for controlling the amount of enhancement. In addition, an adaptive local mean and neighborhood limited empirical mode decomposition algorithm is also developed to improve in two respects the performance of empirical mode decomposition. It can effectively avoid the gray spots effect commonly associated with traditional empirical mode decomposition when dealing with high-nonstationary images.
文摘Given graphs Gand G, we define a graph operation on Gand G,namely the SSG-vertex join of Gand G, denoted by G★ G. Let S(G) be the subdivision graph of G. The SSG-vertex join G★Gis the graph obtained from S(G) and S(G) by joining each vertex of Gwith each vertex of G. In this paper, when G(i = 1, 2) is a regular graph, we determine the normalized Laplacian spectrum of G★ G. As applications, we construct many pairs of normalized Laplacian cospectral graphs, the normalized Laplacian energy, and the degree Kirchhoff index of G★G.