Effective composite image detection method based on feature inconsistency of image components

This paper proposes an effective composite image detection method that uses the feature inconsistency of image components of the composite image to detect tampered regions. The composite image is first divided into image components. Next, the variance of the noise remaining after de-noising in each image component is calculated and used as a feature. Finally, tampered regions are detected using this feature based on a tampering detection rule. Experimental results show that the proposed method has good composite image detection performance.     

磁共振多通道射频接收线圈性能评估

磁共振成像技术追求高信噪比和快速扫描。与单通道线圈相比,多通道线圈具有高信噪比、高分辨率和成像速度快的特点。为服务于射频线圈设计和制作,开发了基于磁共振k空间数据的多通道射频线圈性能评估软件。此软件可以准确方便地计算多通道线圈噪声耦合矩阵和信噪比。     

Convergence Analysis of Wireless Remote Iterative Learning Control Systems with Channel Noise

Channel noise, including sensor‐to‐controller(SC) noise and controller‐to‐actuator(CA) noise, impacts the convergence of wireless remote iterative learning control (ILC) system significantly. In this paper, the relationship between output error, SC noise and CA noise is obtained firstly by super‐vector formulation, and then the norm of output error vector covariance matrix is employed to analyze the convergence of the system in presence of SC noise and CA noise. Upper bound of the norm at any sample time reveals that the SC noise is accumulated only in iteration domain, while the CA noise is accumulated not only in iteration domain but also in time domain. Furthermore, the accumulated effect of the CA noise in time domain is ruled by system matrices, so the values of which determine the effect of the CA noise is greater or less than that of the SC noise on convergence of the system. Finally, some simulation results are given to illustrate correctness of the result.     

复杂背景下弱小目标的检测*

复杂背景下低信噪比弱小目标的检测是当今目标捡测的一个热点课题。为了检测到弱小目标,首先对图像进行复杂背景抑制,以达到抑制背景、提高信噪比的目的,然后比较三种方法的背景抑制能力,最后对抑制效果好的图像进行图像分割来进行弱小目标检测。     

噪声系数的测量方法研究

该文介绍了三种测量噪声系数的方法：增益法,Y因子法和冷源法。重点介绍了当我们做精确测量时Y因子法的不足和冷源法的突破以及给出了这两种方法的实际测试例子。     

基于数据库语言的网站后台编程的技术分析

数据库系统在整个动态Web站点中具有重要的支撑作用,网站的数据库系统主要伴随网站的后台而存在。本文主要是针对数据库在网站中的关键作用进行分析,探讨数据库对网站后台编程的影响因素,从而作出相关的编程技术分析,并以数据库设计为出发点,提出网站后台编程的相关优化建议。     

噪声信道下输出耦合复杂动态网络的状态估计

文中研究了一类带有噪声的复杂动态网络的状态估计问题,不同于现有的根据节点的状态变量构造观测器的方法,文中利用节点的输出变量构造观测器,并基于积分控制的思想提出了一种估计网络状态的新方案。根据李雅普诺夫稳定性判据,所提出的构思的可行性得到了论证,并且以线性矩阵不等式的形式给出了状态估计的充分条件。分别以无标度网络和小世界网络为模型,以Lorenz混沌映射作为复杂网络的节点进行数值化仿真。研究表明,这种方法能够使系统状态的估计误差收敛于0,仿真的结果进一步证明了文中所提方案的有效性。     

动态背景下的运动目标检测

针对动态背景下运动目标检测的问题,最大限度地降低背景对运动目标检测的影响,提出了一种基于相位相关法和傅里叶梅林变换的动态背景下运动目标检测算法.动态背景下运动目标检测的主要部分是背景运动补偿,首先利用相位相关法和傅里叶梅林变换估计全局运动参量,然后根据全局运动参量利用双线性内插法进行背景匹配,最后对配准后的图像利用帧间差分法提取运动目标.实验表明,该算法具有一定的鲁棒性,能有效地检测动态背景下的运动目标.