After a novel speed function based on local gradients of differencing image , object variances and background variances was defined , an improved evolution equation for segmentation curve was obtained , and then different moving objects were segmented 定义了一种新的基于差分图像的局部梯度、目标的方差和背景的方差的速度函数,得到了改进的分割曲线的演化方程,分割出不同的运动目标。
Using the approximation form of lumped mass matrix instead of the mass matrix in finite element discretization in space , backward differencing scheme in time , an implicit computational scheme is yielded , it proved the convergence estimate for this implicit scheme 对有限元离散中引起较大误差的质量矩阵,采用了近似形式的集总质量矩阵来代替,时间项采用向后差分,得到了一个隐式的计算格式,证明了计算格式的收敛性及其收敛速度估计。
The discretization process is deduced in detail , and the final iteration formula is given . in the discretization equations , higher order upwind differencing scheme is introduced into the calculation of the convection flux , whereas as for diffusion term , a central differencing scheme is taken into account 文中就具体离散过程进行了推导,给出了最终的迭代公式,其中,对微分方程的离散采用显式格式、对流项采用高阶迎风差分格式、扩散项应用中心差分格式。
Become a kind of new electronics circuit - current - mode circuit . it is replacing the traditional design method of the voltage - mode in the high frequency high - speed signal processing realm 。 this thesis mainly discussed the modified second - generation current conveyors based on the current - mode kinds of new cuicuit components , they are stronger modified standard current - mode parts in fuctions on this foundation . mainly including the modified differential difference current conveyor ( mddccii ) 、 the fully balanced second generation current conveyor ( fbccii ) 、 ( full balances ) four - terminal floating nullor ( fbftfn ) and the current differencing buffered amplifier ( cdba ) , they are all function very strong standard current - mode parts , they all can provide some circuit functions of better than general operation amplifier , because they have the voltage importation and the current importation , therefore use it since can carry out the voltage - mode signal processing circuit expediently , can also carry out the current - mode signal processing circuit expediently , and have to increase the benefit bandwidth to accumulate more widely than the voltage - mode , but have their advantages more according to the current - mode filter of the modified current conveyor , because it constitutes in brief , the filter wave function is stronger and they are better than in general use operation amplifier of many advantages , be easy to composing for example 、 high speed 、 frequency bandwidth 、 the power supply voltage requests low 、 consume small , the impedance is different from etc . advantages , otherwise they have biggish dynamic range , and flexible circuit synthesize , so they are the best active parts 从第二代电流传输器ccii入手,重点研究了以下几种改进型的第二代电流传输器:改进的差动差分电流传输器mddccii 、全平衡第二代电流传输器fbccii 、多输出四端浮地零器ftfn 、全平衡四端浮地零器fbftfn 、电流差分缓冲放大器cdba的电路结构及其模型。然后在此基础上系统地研究了基于这几种改进型的第二代电流传输器的滤波器的设计方法,主要方法和结果如下:利用mddccii设计了差分式连续时间电流模式低通、带通滤波器;电流模式跳耦结构考尔低通滤波器;利用fbccii设计了带通二阶节滤波器及电流模式双二阶通用滤波器;设计了基于多输出端ftfn的电流模式二阶通用滤波器电路;通过数字化开关选择的基于fbftfn的电流模式通用滤波器;设计了基于最少个数电流缓冲放大器(两个cdba )的多功能通用电流模式滤波器及其在非理想因素情况下分析。设计滤波器的主要方法是采用级联设计、运算模拟(信号流图法)和反馈设计(跳耦法) 。
Because of the low angle is often beyond the distinguishing range of music algorithm , to get better doa estimation results , we make use of the well performance elevation distinguishing of the transform based covariance differencing algorithm , improve and apply it to doa estimation , which can both reduce the correlation between signals and improve target ’ s elevation distinguishing 但是由于低空目标的仰角常常超出了music算法的角度分辨范围,为了获得较好的仰角估计效果,本文利用基于变换的协方差对消算法在角度分辨上的良好性能,将其与改进,应用于低空目标doa估计,既减小的信号的相关性,又提高了角度的分辨率。
Moreover , video control program to implement internal function of fpga is designed including video capture time sequence control , ping - pang frame buffer read and write time sequence control and lcd display time sequence control , and program ' s simulation and analysis is also provided . at last , this paper presents a portable iv ' s video processing system , and proposes three buffer strategy to control capture buffer . and a moving object detection algorithm of combing an adaptive background subtraction technique with a three - frame differencing is adopted 设计了基于fpga系统结构的车载视频显示电路板;利用单片机io口模拟i2c时序,实现了视频解码芯片控制;利用fpga实现视频控制,研究了采集通道时序控制、双帧存ram读写时序控制及lcd显示时序控制的方法,并进行了软件仿真和分析;设计了车载视频检测系统方案,给出了管理采集缓冲区的三帧缓冲策略,采用综合三帧差分和自适应背景相减的算法实现运动检测,连通体检测去除虚目标,仿真实验证明其有效性,同时分析了该算法在dsp视频检测系统中的简单实现方法。
Some features and feature groups that can well show the characteristics of urban environment are founded through experiment to compare the performances of different features . for all the researches in this paper , the radarsat images in 1998 and 2000 and the spot image in 2000 of beijing and field survey data are used to validate . the experimental result demonstrates that a higher change detect accuracy can be obtained < wp = 4 > through the texture differencing method than through the image differencing method based on gray level and the wide application of texture differencing method for urban change detection in sar images 本文开展的各项研究工作,均使用北京地区1998年、 2000年radarsat图像、 2000年spot图像及实地考察数据进行了验证,实验结果表明,与灰度差值法相比,本文所提出的纹理差值变化检测方法获得了更好的检测结果,也表明了纹理差值变化检测方法在合成孔径雷达图像和变化检测中良好的应用前景。
Through the empirical studies on the issue of static beta stability , the author has the following findings : ( 1 ) the estimation of beta will not be invariant to the length of the differencing interval over which the returns of stocks are measured . ( 2 ) most stocks have intra - period stable betas . ( 3 ) 总的来看,研究普遍认同导致系数差异的影响因素主要有三大类:宏观经济因素(如经济周期、利率、通货膨胀等) 、公司的基本特征(如公司的规模、财务结构等)和公司的行业类别及所归属的经济部门。