基于混合相关滤波信息融合再检测的目标跟踪算法

为了减小在目标跟踪过程中目标形变和复杂背景变化对跟踪效果的影响,提出一种基于混合相关滤波信息融合再检测的目标跟踪算法。首先,利用相关滤波算法提取到目标的方向梯度直方图HoG特征,利用颜色模板得到目标的颜色特征,计算两个模板的采样得分;其次,再将两者的特征信息用线性组合的形式进行特征信息融合确定目标位置,跟踪过程中,根据设定的阈值条件选择两个模板采样较大的得分再检测目标的位置;最后,输出所有帧目标位置的结果。与其他的算法进行比较,该算法在应对目标形变和背景杂波方面有较好的跟踪效果。     

基于重叠光栅和啁啾光栅的双波长光纤激光器

研究光寻址电位传感器(LAPS)的器件噪声特性 。通过对LAPS半导体场效应器件的结构分析,建 立LAPS的理论模型,并进一步分析LAPS器件噪声信号的来源、种类及特性。以 pH缓冲液中H离子 浓度为检测对象,搭建基于NI采集卡和Labview环境的LAPS测试系统,对影响LAPS信号噪声 特性的光源 波长、光源调制频率、光源强度和Si衬底厚度等因素进行了仿真和实验研究。结果表明,增 大光源波长和光源强度 是提高输出信号幅值和信噪比(SNR)的最有效方法。     

Periodical rocking long period gratings in PANDA fibers for high temperature and refractive index sensing

We report periodical rocking long period gratings (PR-LPGs) in PANDA fibers fabricated with CO2 laser. The PR-LPGs achieve very high coupling efficiency of 19 dB with 12 periods and a 3.5° twist angle in just one scanning cycle, which is much more effective than the conventional CO2 laser fabrication technique. This type of LPGs exhibits polarization-selective resonance dips which demonstrate different sensitivities to environmental parameters. The high temperature and external refractive index sensitivities are measured simultaneously, so it can be used as a wavelength-selective polarization filter and sensor. This work has been supported by the National Natural Science Foundation of China (No.61605168), the Natural Science Foundation of Hebei Province (No.F2016203392), the College and University Natural Science Foundation of Hebei Province (No.QN2016078), the Science and Technology Project of Qinhuangdao City (No.201601B050), and the Intramural Doctoral Foundation of Yanshan Universtiy (No.B1011). E-mail:jinwa@ysu.edu.cn      

All-fiber mode converter based on superimposed long period fiber gratings

In this paper, a novel broadband all-fiber mode converter is proposed and experimentally demonstrated. Through writing a pair of superimposed long period fiber gratings (SLPFGs) in tow-mode fiber (TMF) with a CO₂ laser, the mode converter can realize the conversion from LP₀₁ to LP₁₁ owing to the phase matching condition. Numerical and experimental results show that the bandwidth of this mode converter is 3 times broader than that of a single grating converter. The converter has low loss, high coupling efficiency, small size and is easy to fabricate, so it can be widely used in mode-division multiplexing.     

A multi-wavelength fiber laser based on superimposed fiber grating and chirp fiber Bragg grating for wavelength selection

In this paper, a new type of multi-wavelength fiber laser is proposed and demonstrated experimentally. Superimposed fiber grating (SIFG) and chirp fiber Bragg grating (CFBG) are used for wavelength selection. Based on gain equalization technology, by finely adjusting the stress device in the cavity, the gain and loss are equal, so as to suppress the modal competition and achieve multi-wavelength lasing at room temperature. The experimental results show that the laser can output stable multi-wavelength lasers simultaneously. The laser coupling loss is small, the structure is simple, and it is convenient for integration, so it can be widely used in dense wavelength division multiplexing (DWDM) system and optical fiber sensors.