提出了一种基于CEM(constrained energy minimum)的高光谱影像目标检测算法。利用虚拟维数实现高光谱影像端元数目的估计,进而获取目标端元。利用基于最大噪声分量算法对原始影像进行降维,在虚拟维数的基础上保留合理的主成分数量。根...提出了一种基于CEM(constrained energy minimum)的高光谱影像目标检测算法。利用虚拟维数实现高光谱影像端元数目的估计,进而获取目标端元。利用基于最大噪声分量算法对原始影像进行降维,在虚拟维数的基础上保留合理的主成分数量。根据提取的目标端元,利用一种改进的CEM算子进行目标检测。实验结果表明:该算法能够获得较高质量的目标检测效果。展开更多
A 20 cm focal length normal incidence vacuum ultraviolet （VUV_20 cm） monochromator with a fast time response has been developed for measuring edge impurity line emission in the wavelength range of 300-2000 A on an H...A 20 cm focal length normal incidence vacuum ultraviolet （VUV_20 cm） monochromator with a fast time response has been developed for measuring edge impurity line emission in the wavelength range of 300-2000 A on an HL-2A tokamak. An aberration corrected concave holographic grating with 1200 grooves/mm is adopted in the monochromator, which provides a wavelength dispersion of 40 A mm-1. The aperture is f/4.5. A channel electron multiplier is used as a detector. The time resolution of the system is 17 μs. Wavelength calibration of the system has been done by using a hollow cathode light source in the laboratory with helium and argon gases. The obtained signals of helium and argon spectra are very strong since the inner surface of the monochromator vacuum chamber is blackened and the stray light level is then significantly reduced. The optical property of the system has been examined by scanning the width of the entrance and exit slits. The system is then installed at the mid-port of the HL-2A tokamak and typical line emissions from the HL-2A plasma are measured. Time behaviors of edge impurity line emissions are observed with the fast time response system in different plasma confinement regimes, especially in the H-mode discharges. The result shows that the VUV_20 cm system works very well to measure the edge impurity line emissions in the edge localized modes phase of H-mode discharges.展开更多
文摘提出了一种基于CEM(constrained energy minimum)的高光谱影像目标检测算法。利用虚拟维数实现高光谱影像端元数目的估计,进而获取目标端元。利用基于最大噪声分量算法对原始影像进行降维,在虚拟维数的基础上保留合理的主成分数量。根据提取的目标端元,利用一种改进的CEM算子进行目标检测。实验结果表明:该算法能够获得较高质量的目标检测效果。
基金partly supported by National Natural Science Foundation of China (Nos. 11375057 and 11505051)the National Magnetic Confinement Fusion Program of China (Nos. 2014GB108003 and 2015GB104003)
文摘A 20 cm focal length normal incidence vacuum ultraviolet （VUV_20 cm） monochromator with a fast time response has been developed for measuring edge impurity line emission in the wavelength range of 300-2000 A on an HL-2A tokamak. An aberration corrected concave holographic grating with 1200 grooves/mm is adopted in the monochromator, which provides a wavelength dispersion of 40 A mm-1. The aperture is f/4.5. A channel electron multiplier is used as a detector. The time resolution of the system is 17 μs. Wavelength calibration of the system has been done by using a hollow cathode light source in the laboratory with helium and argon gases. The obtained signals of helium and argon spectra are very strong since the inner surface of the monochromator vacuum chamber is blackened and the stray light level is then significantly reduced. The optical property of the system has been examined by scanning the width of the entrance and exit slits. The system is then installed at the mid-port of the HL-2A tokamak and typical line emissions from the HL-2A plasma are measured. Time behaviors of edge impurity line emissions are observed with the fast time response system in different plasma confinement regimes, especially in the H-mode discharges. The result shows that the VUV_20 cm system works very well to measure the edge impurity line emissions in the edge localized modes phase of H-mode discharges.
