变换

Such characteristic vector can be applied to further signal processing and fault diagnosis of high current LIA.

应用小波变换具有良好的时频局部特性，通过对强流直线感应加速器脉冲信号的去噪声、信号突变点检测以及时间间隔测量等处理，表明小波变换在LIA信号处理中有广泛的应用前景；利用小波包分析的每个节点都代表了对应频带的信号特征的特点，对"神龙一号"快脉冲波形数据进行小波包变换，以各频带信号能量为元素构造特征向量，实现了高维波形数据的特征值提取，达到了数据压缩和降维的目的，为进一步实现LIA故障智能诊断、预测维护提供了一种可行的途径。

In the new algorithm,the circle detection problem is decomposed into two stages consisting of a 2D Hough transform to find circle centre and a 1D Hough transform to determine the radius.

利用局部梯度信息将检测圆所需的3D Hough变换转化为一个2D Hough变换检测圆心位置和一个1D Hough变换检测圆的半径。

This dissertation selects two-dimension binary image as watermark information, and selects audio as embedding object, and embed the watermark in the coefficient of the DFT domain, the DCT domain, the DWT domain.

本文以直观的二值图像作为水印信息，以音频数据为嵌入对象，分别在离散傅立叶变换域、离散余弦变换域、离散小波变换域的系数上嵌入水印。

Its mean function, variance function and correlation coefficient function can be gained by the method in time domain.

该方法首先在时域进行全程分析，得到相关系数平稳过程的均值函数、方差函数和相关系数函数，然后可以对其进行傅里叶变换、短时傅里叶变换或小波变换，给出相关系数平稳过程的谱密度，同时提出了随机项谱密度和趋势项谱密度的概念。

From the history of Matrix and Transformation and the development of curriculum at home and abroad, putting matrix combined with the transformation, and orienting the study in 2×2 rank matrix, boosting matrix up the geometrical visualization as a algebra objects are a new perspective on knowing matrix.

从矩阵和变换的历史发展过程和国内外矩阵和变换的课程设置来看，把矩阵与变换相结合，并定位在2×2阶上研究矩阵，增强作为代数对象的矩阵的几何直观性，是认识矩阵的一个新视角。

In order to eliminate the influence caused by the nonminimum phase characteristic of a common Boost DC／DC converter, Viswanathan K has proposed a novel tristate Boost DC／DC converter. For enhancing performance, the statespace averaging model of this converter was first presented in this paper. Due to the nonlinear nature in this model, an inputoutput feedback linearization technique was adopted, and a complete controllable linear system was obtained. Then a statefeedback control strategy was designed based on this linear system. Simulation results show that the proposed control strategy can assure constant output voltage in a wide range, so as to realize the stability of the system during large fluctuation of power supply and load disturbance. Good dynamic performance can also be achieved.

针对 Viswanathan K为消除普通BOOST DC／DC变换器的非最小相位特性而提出的三态Boost DC／DC变换器，为进一步提高这种电路拓扑的性能，在建立了变换器状态空间平均模型的基础上，针对其多变量、非线性特点，采用输入输出线性化将其转化为一个完全可控的线性系统，在此基础上应用现有成熟的线性控制策略进行了控制系统的设计，并且采用MATLAB进行仿真验证，结果表明：这种非线性控制策略可以确保输出电压在大范围内恒定可调，且即使存在大范围扰动(输入电压和负载变化均较大)的情况下，系统也可以确保稳定性和良好的动态性能。

In the first step,through using the formula of the conformal transformation,a continuous medium with regulation boundary in original area could be transformed to a homogeneous medium with anomalous boundary in complex area,so the new constant velocity field could be more adapt to the current Stolt migration's conditions.

首先，利用保角变换法可将不规则边界的单连通区域转变成规则边界的原理，将规则边界的连续介质场转变成不规则边界的均匀介质场，使该均匀介质场更适应现有Stolt等偏移方法对速度场的要求；其次，对改变了区域的模型地震记录进行常规的偏移成像处理；再利用推导出的反变换公式对成像结果进行反变换，得出模型的真实偏移成像结果。

Chapter 1 briefs the relation between invariance and computer vision and summarizes the research and application of invariance in computer vision. Chapter 2 first derives the transformations of three camera models, then makes the correpondences between the models and three typical geometrical transformation groups by analysing the transformations respectively. The correspondences supply the theoretical basis for applying geometrical invariants to resolve the problems of computer vision. In Chapter 3, we describe the geometrical invariant theory and prove some geometrical invariants of coplanar points, lines or conics by algebraic method. In order to use the invariants of conic pairs to describe general 2D shapes, we discuss the perspectively invariant representation of planar curves using conies in detail. A system consisted of two TMS320C25 and based on moment invariants is introduced in Chapter 5. The system can recognize more than 30 different shapes of object model or more than 10 plane models with similar shape in real time.

第一章简述了不变性与计算机视觉的关系，以及计算机视觉中的不变性研究和应用概况；第二章推导了计算机视觉中常用三种投影模型的变换关系，通过对这三种变换关系的分析，分别建立了这三种投影模型和几何学中的三种变换群之间的一一对应关系，为几何不变性在计算机视觉中的应用提供了理论基础；在第三章中，我们介绍了几何不变性的理论，并且用代数方法证明了共面点、直线、二次曲线的几何不变量和射影不变量；为了把二次曲线的不变量用于一般二维形状描述，在第四章中我们详细地讨论了用二次曲线实现一般平面曲线的透视不变性表示的方法；第五章介绍了用两片TMS320C25构成的、基于不变矩形特征的运动目标实时识别系统。

The results show that the frequency characteristic corresponds with vortex structures; the detail and approximate characteristics of signal are reflected by wavelet coefficient at different scales; the coefficient map of continuous wavelet transformation reveals the self-similarity of the signal.

采用傅里叶变换和小波变换技术，实现了混合层密度脉动信号的频谱与多分辨率分析，结果表明：信号的频域特性与流场的涡结构相对应，不同层面的离散小波系数反映了不同尺度下信号与图像的细节和平滑近似特征，连续小波变换系数图定性的反映了信号的自相似特征。

A logicaldomain is used as a reference and the mesh movingis implemented according to an appropriate domain transformation.With sometraditional moving mesh methods,the meshes in physical domain may be tangled.To avoid this,the transformations are constructed based on harmonic mapping.Agood feature of the adaptive methods based on harmonic mapping is that existence,uniqueness and non-singularity for the continuous map can be guaranteed fromthe theory of harmonic maps.

在移动网格方法中，需要引进一个逻辑区域作为参考，网格的移动往往通过一个区域变换来实现，网格可能发生缠绕的问题是移动网格方法中一个一直没有解决的问题，我们利用调和映射来构造区域间的变换，使得变换的存在唯一生有了理论的保证，这就为避免网格缠绕打下了基础。

On the other hand, the more important thing is because the urban housing is a kind of heterogeneity products.

另一方面，更重要的是由于城市住房是一种异质性产品。

Climate histogram is the fall that collects place measure calm value, cent serves as cross axle for a few equal interval, the area that the frequency that the value appears according to place is accumulated and becomes will be determined inside each interval, discharge the graph that rise with post, also be called histogram.

气候直方图是将所收集的降水量测定值，分为几个相等的区间作为横轴，并将各区间内所测定值依所出现的次数累积而成的面积，用柱子排起来的图形，也叫做柱状图。