1 太原理工大学 信息工程学院, 太原 030024
2 太原理工大学 大数据学院, 太原 030024
为了最大限度地保留多光谱图像的光谱特性和全色图像的空间细节, 提出基于最小Hausdorff距离和非下采样剪切波变换(NSST)的遥感图像融合方法.首先, 将原多光谱图像进行主成分分析(PCA)获得其第一主分量, 选择NSST对第一主分量和全色图像分别进行分解, 得到相应的低频子带系数和高频子带系数.其次, 对低频子带系数采用基于稀疏表示的融合策略, 稀疏系数与区域空间频率相结合, 根据区域空间频率选择权值, 对稀疏系数进行加权; 对于高频子带系数充分考虑其邻域系数相关性, 提出采用最小Hausdorff距离表征相应区域相关性, 根据相关性不同采用不同的融合策略.最后, 对融合系数进行NSST逆变换得到融合后的第一主分量, 再将新的第一主分量与其他高阶主分量进行PCA逆变换得到融合图像.选择三组QuickBird卫星图像和一组SPOT卫星图像进行测试, 与传统的融合策略算法相比, 本文方法获得的融合结果客观评价指标更优, 且主观视觉效果更好.
遥感图像融合 最小Hausdorff距离 非下采样剪切波变换 主成分分析 稀疏表示 Remote sensing image fusion Minimum Hausdorff distance Nonsubsampled Shearlet transform Principal component analysis Sparse representation
Author Affiliations
Abstract
1 Key Lab of Advanced Transducers and Intelligent Control Systems, Ministry of Education and Shanxi Province, Taiyuan 030024, China
2 Institute of Optoelectronic Engineering, College of Physics & Optoelectronics, Taiyuan University of Technology, Taiyuan 030024, China
3 Fiber Optics Group, Department of Physics, University of Ottawa, Ottawa K1N 6N5, Canada
To obtain high spatial resolution over a long sensing distance in Brillouin optical correlation domain reflectometry (BOCDR), a broad laser spectrum and high pump power are used to improve the signal-to-noise ratio (SNR). In this Letter, we use a noise-modulated laser to study the variation of the Brillouin spectrum bandwidth and its impact on the coherent length of BOCDR quantitatively. The result shows that the best spatial resolution (lowest coherent length) is achieved by the lowest pump power with the highest noise-modulation spectrum. Temperature-induced changes in the Brillouin frequency shift along a 253.1 m fiber are demonstrated with a 19 cm spatial resolution.
060.2370 Fiber optics sensors 060.4080 Modulation 120.5820 Scattering measurements Chinese Optics Letters
2017, 15(8): 080603
Author Affiliations
Abstract
1 Key Lab of Advanced Transducers and Intelligent Control System, Ministry of Education and Shanxi Province, Taiyuan University of Technology, Taiyuan 030024, China
2 Institute of Optoelectronic Engineering, College of Physics and Optoelectronics, Taiyuan University of Technology, Taiyuan 030024, China
We propose and demonstrate a scheme to measure the distribution of temperature along an optical fiber based on pseudo-random sequence modulation. In our experimental work, current modulation with a pseudo-random bit sequence (PRBS) is applied to a laser diode that serves as the Brillouin pump light and reference light. Because of the independence of the spatial resolution on the PRBS length, the measurement range can be extended while maintaining high spatial resolution using a long PRBS length. Temperature-induced changes in a Brillouin frequency shift of 250 m fiber sections are clearly observed with 54 cm spatial resolution by this method.
060.2370 Fiber optics sensors 060.4080 Modulation 120.5820 Scattering measurements 290.5830 Scattering, Brillouin Chinese Optics Letters
2015, 13(8): 080604
1 太原理工大学 新型传感器与智能控制教育部与山西省重点实验室,太原 030024
2 太原理工大学 物理与光电工程学院 光电工程研究所,太原 030024
根据光纤布里渊频移量随温度变化的特性,提出一种基于布里渊光相干反射技术的分布式光纤温度传感器.利用噪声信号的无周期特性,采用高斯白噪声信号对系统的光源进行电流调制,克服了现有布里渊光相干反射技术无法同时兼顾传感距离和空间分辨率的问题.实验研究表明,该传感器在253m的普通单模光纤上实现了分布式温度测量,获得了54.6cm的空间分辨率和±1.07℃的温度测量准确度.
光纤传感器 布里渊散射 高斯噪声 调制 温度传感 Optical sensors Brillouin scattering Gaussian noise Modulation Temperature sensor 光子学报
2015, 44(10): 1006004
