基于混合遗传算法优化的MLP神经网络的调制方式识别

提出了一种基于遗传算法与多层感知神经网络的调制识别方法,运用改进遗传算法优化的多层感知神经网络分类器对各种调制信号的特征矢量进行分类识别.利用遗传算法的高效全局特性,克服了传统BP算法易于陷入局部最优解的缺点,同时在遗传算法基础上增加梯度下降算子,加快了收敛速度,使得分类器的识别率、收敛速度和鲁棒性得到明显改善,仿真实验的结果证明了此方法的有效性和可行性.     

Novel averaging window filter for SIFT in infrared face recognition

The extraction of stable local features directly affects the performance of infrared face recognition algorithms.Recent studies on the application of scale invariant feature transform(SIFT) to infrared face recognition show that star-styled window filter(SWF) can filter out errors incorrectly introduced by SIFT.The current letter proposes an improved filter pattern called Y-styled window filter(YWF) to further eliminate the wrong matches.Compared with SWF,YWF patterns are sparser and do not maintain rotation invariance;thus,they are more suitable to infrared face recognition.Our experimental results demonstrate that a YWF-based averaging window outperforms an SWF-based one in reducing wrong matches,therefore improving the reliability of infrared face recognition systems.     

水下无线光OOK信道误码率分析

现有的矢量辐射输运（VRT）理论无法分析有限孔径条件下水下无线光通信信道特征,因此VRT误码率计算结果并不能很好地与实际系统相符。在分析水下光OOK信号激光传输模型的基础上,根据水下有限孔径光信道的特征,对三类海水中可见光水下通信系统的误码率进行了仿真和评估。仿真结果表明,水下光OOK系统可靠视频传输距离上限分别为远洋108m,近海65m和海湾11m,该结果为水下实时高码率激光通信系统设计提供了参考。     

Novel system for modulated lidar parameter optimization

We present a novel system for parameter design and optimization of modulated lidar. The system is realized by combining software simulation with hardware circuit. This method is more reliable and flexible for lidar parameter optimization compared with theoretical computation or fiber-simulated system. Experiments confirm that the system is capable of optimizing parameters for modulated lidar. Key parameters are analyzed as well. The optimal filter bandwidth is 200 MHz and the optimal modulation depth is 0.5 under typical application environment.     

1064nm红外激光大气布里渊频移量模型

1064nm激光常用于大气环境监测。以激光信号在传输介质中布里渊散射频移量模型为基础,依据相关大气数据建立1064nm激光大气中布里渊散射信号检测的大气探测模型。该模型将布里渊频移量归一为只与大气高度这一单参数相关的函数,详细地描述了0～1000km范围内大气布里渊频移量的连续分布状态。结果表明在0～1000km的海拔高度范围内,1064nm激光大气的布里渊散射频移量以非单调的形式分布在0.5～1.2GHz之间。     

激光单稳频指标的激光计量红外光谱仪精度分析

在傅里叶变换红外光谱仪中,采用激光计量光程差可提高光谱的测量精度。激光波长作为光程差测量的基准单位,其线宽和稳频特性直接决定了光程差的误差,进而影响光谱的测量精度。根据光谱仪的干涉原理,通过傅里叶逆变换和误差分析方法,建立了光谱测量相对误差与激光单稳频指标之间的理论模型,并对该模型进行了仿真计算。结果证明,该模型可作为设计激光计量光程差光谱仪系统的理论依据。