In order to overcome the shortcomings that the reconstructed spectral reflectance may be negative when using the classic principal component analysis （PCA）to reduce the dimensions of the multi-spectral data, a nonne...In order to overcome the shortcomings that the reconstructed spectral reflectance may be negative when using the classic principal component analysis （PCA）to reduce the dimensions of the multi-spectral data, a nonnegative constrained principal component analysis method is proposed to construct a low-dimensional multi-spectral space and accomplish the conversion between the new constructed space and the multispectral space. First, the reason behind the negative data is analyzed and a nonnegative constraint is imposed on the classic PCA. Then a set of nonnegative linear independence weight vectors of principal components is obtained, by which a lowdimensional space is constructed. Finally, a nonlinear optimization technique is used to determine the projection vectors of the high-dimensional multi-spectral data in the constructed space. Experimental results show that the proposed method can keep the reconstructed spectral data in [ 0, 1 ]. The precision of the space created by the proposed method is equivalent to or even higher than that by the PCA.展开更多
Metal-dielectric subwavelength gratings under s-polarized and p-polarized visible radiation are studied for discovering their intriguing behaviors of spectral resonance and color property.The dependence of their reson...Metal-dielectric subwavelength gratings under s-polarized and p-polarized visible radiation are studied for discovering their intriguing behaviors of spectral resonance and color property.The dependence of their resonance and color on grating parameters as well as angle of incidence and position of plane of incidence is also analyzed.For s-polarized light,the behavior of spectral resonance with single peak and higher peak efficiency is found.While transmission spectra for p-polarized light are not able to achieve a behavior like that of s-polarization,creating a perceived color is feasible.Moreover,a security grating with distinctive color shifts has been designed and its resonant properties as well as related color variation have also been provided.展开更多
基金The Pre-Research Foundation of National Ministries andCommissions (No9140A16050109DZ01)the Scientific Research Program of the Education Department of Shanxi Province (No09JK701)
文摘In order to overcome the shortcomings that the reconstructed spectral reflectance may be negative when using the classic principal component analysis （PCA）to reduce the dimensions of the multi-spectral data, a nonnegative constrained principal component analysis method is proposed to construct a low-dimensional multi-spectral space and accomplish the conversion between the new constructed space and the multispectral space. First, the reason behind the negative data is analyzed and a nonnegative constraint is imposed on the classic PCA. Then a set of nonnegative linear independence weight vectors of principal components is obtained, by which a lowdimensional space is constructed. Finally, a nonlinear optimization technique is used to determine the projection vectors of the high-dimensional multi-spectral data in the constructed space. Experimental results show that the proposed method can keep the reconstructed spectral data in [ 0, 1 ]. The precision of the space created by the proposed method is equivalent to or even higher than that by the PCA.
基金Supported by the National Natural Science Foundation of China (61008036)China Postdoctoral Science Foundation(20110490779)
文摘Metal-dielectric subwavelength gratings under s-polarized and p-polarized visible radiation are studied for discovering their intriguing behaviors of spectral resonance and color property.The dependence of their resonance and color on grating parameters as well as angle of incidence and position of plane of incidence is also analyzed.For s-polarized light,the behavior of spectral resonance with single peak and higher peak efficiency is found.While transmission spectra for p-polarized light are not able to achieve a behavior like that of s-polarization,creating a perceived color is feasible.Moreover,a security grating with distinctive color shifts has been designed and its resonant properties as well as related color variation have also been provided.
