点变换

词组短语

point transformation

与点变换相关的网络例句 [注：此内容来源于网络，仅供参考]

At the same time, combining with the actual condition of delivery pipeline of our country and some prevalent leak detection and location methods, this paper raised a method, which is based on wavelet analysis and negative- pressure-wave to detect and locate the leakage. Jobs in the paper are as follows:As affected by gas density, pressure, specific heat and pipe material, the velocity of negative-pressure-wave improved depending on the energy conservation. At one time, taking the affection of velocity of gas flow, the location formula was modified in some degree.When locating the leaks with location formula, the iterative approach algorithm was adopted as a new method to increase the location accuracy level of system.Multi-scale decomposition and reconstruction of wavelet transform is utilized to filter the noise of negative-pressure-wave, which was brought by leakage. With the capacity to detect the signal singularity fast and accurately, wavelet transform was used to catch the break point of pressure signal. The work improved the accuracy of At in location formula, accordingly improved the location accuracy.Wavelet is a suitable tool for signal analysis. The distinct character is that the mother-wavelet is of optional. That means choosing different mother-wavelet will get different analysis result. So we studied how to choose mother-wavelet and its scale for signal singularity detection. The method is to choose a wavelet by regularities of the wavelet and the signal.Finally, a plan, which bases on SCADA system for inspection and detection of natural gas leakage, is proposed in the article.

其中，主要进行了以下几方面的工作：针对泄漏产生的负压波在管道中的传播速度受媒介的密度、压力、比热及材质等因素的影响，而非声波在空气中传播的速度，本文利用能量守恒原理，对其进行了修正；考虑到管内气体流速对压力波速的影响，对原始的负压波定位公式进行了一定程度的改进，并在利用定位公式进行泄漏点定位时采用逐步迭代逼近算法，提高了系统的定位精度；利用小波变换的多分辨率分解和重构技术，对采集到的管道发生泄漏时产生的负压波信号进行了降噪处理；并利用小波变换技术对信号奇异点的快速、准确的识别能力，对经上述消噪后的负压波信号进行了奇异点捕捉，精确捕捉的结果提高了定位公式中上下游站点采集到的负压波奇异点的时间差△t的精度，从而进一步提高了定位的精度；考虑到小波变换是一种基波可变的信号分析工具，也就是说，不同的小波基波对信号分析的结果将有很大差别，这势必影响最终的处理结果，因此，我们又对比分析了本课题中小波基及尺度的选择问题，依据规则性系数相似性原理对母小波的选择进行了探索性研究；最后，还提出了基于SCADA的泄漏检测与定位系统的软件开发构想及系统的嵌入方案。

For the diffractive optical element realizing beam shaping in the fractional Fourier transform domain,the transform matrix calculated by the discrete sampling points was compared with that calculated by the Fresnel integral,and the discretization error of the intensity distribution on the output plane was qualitatively obtained.

针对分数傅里叶变换衍射光学光束整形器件，比较了按离散点与按菲涅耳积分计算得到的变换矩阵间的差距，从中分析得出按离散点计算的变换矩阵引入的离散化误差与分数傅里叶变换系统参数的关系。

For reducing boundary distortion area, the elevations of grid DEM are viewed as a discrete sequence under a generalized coordinate, so that the boundary problem of two-dimensional discrete wavelet transform is turned into the boundary problem of one-dimensional discrete wavelet transform, which not only greatly reduces the boundary distortion area, improves the precision of reconstructed DEM data near the boundary, but also decreases the number of zeros adding on the boundary for wavelet transform, and boosts the compression ratio. On the basis of analyzing the distribution characteristics of coefficients in low and high frequency bands, a mixed entropy coding plan is applied, and a high efficient quantizator called"self-adaptive hard threshold"is established, which is helpful for improving the precision of the reconstructed DEM data and for enhancing compression ratio.

为了减小小波变换山区格网DEM数据压缩中边界失真区域，将山区格网DEM高程值视为广义坐标下的离散随机序列，把二维离散小波变换中的边界问题转换为一维离散小波变换中的边界问题，不仅大大减少了小波变换边界失真区域，提高了重构DEM数据边界点的精度，而且减少了边界补零个数，提高了压缩比；通过对山区格网DEM数据小波变换低频区和高频区变换系数分布特点的分析，采取了霍夫曼—游程混合熵编码方案，设计了高效、低失真的"自适应硬阈值"量化器，即对低频区变换系数不进行量化，直接进行霍夫曼编码；对高频区变换系数则先用"自适应硬阈值"方法量化处理，再进行游程编码。

According to if there exists a one to one mapping between the two point sets to be matched, PPM can be divided into the case of complete matching and the case of incomplete matching. According to transformation type between the two point sets, PPM can be divided into the affine (including Euclidean and similarity) case and the projective case.

点模式匹配问题，根据待匹配的两个点模式是否存在一一对应的匹配关系，可分为完全匹配情形和不完全匹配情形；根据两个点模式之间满足的几何变换关系，可分为仿射变换（包括相似变换和欧氏变换）情形和射影变换情形。

A method based on linear singularity analysis of image is presented. The improved method, called Directional Beamlet Transform is better than traditional Beamlet transform about directional information of image and has the ability of representing linear-singularity of image. According to the analysis of linear singularity, edge detection is transferred to detecting singularity point in the coefficient matrix of DBT.

针对基于图像像素点分析的边缘提取方法存在无法同时满足高抑噪性、连续性、定位性等问题，本文提出了方向Beamle 变换方法，在定义图像线奇异性的理论基础上，利用DBT 对图像进行线奇异性分析，依据Beamlet 变换具有的线段提取能力，将图像边缘检测问题转化为方向Beamlet 变换系数矩阵中奇异点的检测问题，以降低噪声点对边缘检测结果的影响。

When the viewpoint is changing quickly, the rendering algorithm ignores some details of the diffuse component, otherwise the scene is rendered more precisely. The Specula highlight is dependent of the viewpoint, it must be processed in real time. We present an algorithm to get rid of the area that does not contain specula highlight quickly and calculate only the area that contains the specula highlight. In order to calculate the specula reflection and refraction component, we presented a new raytracing algorithm based on the environment map transformation. The environment maps are constructed at the sample points of the scene in the preprocessing phase. We add depth information in the environment maps and generate the exact reflection and refraction intensity with the transformation of a few pixels.

对于表面光亮度漫射分量，由于它与视点无关，可以把面片按照光照细节的分布预剖分成层次结构，然后在实时漫游时根据场景变化的快慢决定绘制的细致程度；对于镜面高光分量，由于它与视点有关，必须实时处理，我们提出了一种快速高光裁剪算法，通过简单测试，去除那些不包含高光的区域，只处理包含高光的区域；对于镜面反射分量和折射分量，我们提出了一种基于环境映照变换的快速光线跟踪算法，预先在场景的离散采样点处建立环境映照，然后根据入射点的位置，把邻近采样点处的环境映照上相关象素处的可见点变换过来，求取反射分量和折射分量。

Firstly, we study the theory and application of jump points and sharp cusp points detection by wavelet transform. The studied object is from white noise to correlated noise. We have studied the properties of correlated noise in wavelet transform, and the properties of deterministic function with jumps and sharp cusps in wavelet transform.

首先研究了研究了小波变换在突变点与尖点检测中的理论与应用，研究的对象由白噪到相关噪声，研究了相关噪声在小波变换的性质，以及对具有突变点和尖点的函数在小波变换下的性质，有关这些性质，我们均以定理形式给出，并给出了详细的证明。

In the inliers sub-set, perspective transformation model was used to estimate the point transformation matrix between two images accurately.

在内点域内运用透视变换模型精确地估计出图像间的点变换关系。

In this algorithm, Harris corner detector is used to extract feature points, which gains sub pixel precision for features extraction. Then, a pseudo matching set is obtained by comparing local neighborhoods of features through intensity cross correlation method and these pseudo matches are divided into inliers and outliers using robust RANSAC algorithm.

此算法采用 Harris角检测算子进行特征点提取，使提取的精度达到了亚像素级，然后以特征点邻域灰度互相关法进行特征点匹配得到了初步的伪匹配集合，并运用稳健的RANSAC算法将伪匹配点集合划分为内点和外点，在内点域上运用 L M优化算法精确地估计出了图像间的点变换关系，最后采用颜色插值对交接处进行颜色过渡。

By this algorithm, the image point transformation of multisource image data can be timely completed.

利用本算法，可以实时地完成多源图象的各种点变换处理

与点变换相关的网络解释 [注：此内容来源于网络，仅供参考]

alteration switch：变换转移点

allowable switching current 容许合闸电流 | alteration switch 变换转移点 | alternation switch 变更开关; 交替开关; 转换开关

extended point transformation：开拓的点变换

extended plane 扩张平面 | extended point transformation 开拓的点变换 | extended predicate calculus 广义谓词演算

extended point transformation：开拓点变换

extended pitch chain 加长节距链 | extended point transformation 开拓点变换 | extended precedence grammar 扩充优先文法

internal transformation：内点变换

internal tangent of two circles 二圆的内切线 | internal transformation 内点变换 | internal vertex 内部顶点

floating point truncation：浮点截断

浮点变换 floating point transformation | 浮点截断 floating point truncation | 浮点类型 floating point type

contraflexure：反挠 反挠曲 反弯曲 反向曲线变换点 反向弯曲

contraflailrowcleaner反击甩刀式行间清理器 | contraflexure反挠 反挠曲 反弯曲 反向曲线变换点 反向弯曲 | contraflexurepoint反挠点

extended point transformation：开拓点变换

extended pitch chain ==> 加长节距链 | extended point transformation ==> 开拓点变换 | extended precedence grammar ==> 扩充优先文法

floating point transformation：浮点变换

浮点制 floating point system | 浮点变换 floating point transformation | 浮点截断 floating point truncation

point curve transformation：点线变换

点对应 point correspondence | 点线变换 point curve transformation | 点方程 point equation

point surface transformation：点面变换

点球 point sphere | 点面变换 point surface transformation | 点全步法 point total step method