变换点

SIFT（Scale Invariant Feature Transform） local feature is chosen because of its scale invariance and the property of accurate key-point localization.The Euclidean distance between different SIFT feature vectors is defined as the measure of similarity to get the pre-matched key-point pairs.The affine transform model is used to realize the registration.In order to get the accurate affine transform parameter,the principal of affine transform error is used to get rid of mismatched key-point pairs from the pre-matched pairs.

该方法选取具有良好尺度、旋转不变性以及精确特征点定位能力的SIFT局部特征，使用其特征向量间的欧氏距离作为相似性度量进行特征点匹配，并依据仿射变换误差准则去除奇异匹配特征点对，采用仿射变换的几何模型，实现了遥感图像的快速自动配准。

This method represents the virtual objects in Euclidean space instead of in affine space, which is consistent with the popular graphics rendering tools such as OpenGL and is more common in practice. A new classification based local and global tracking strategy to match features between the reference image and the currently frame directly is presented, which enables the augmented reality system working effectively even under large changes of viewing angles. A novel affine coordinate system definition method based on a collection of feature points is also proposed, which makes the tracking method effective even when not all the reference points are detected during the whole process, as long as there are at least four pairs of reference points correspondences.

该方法以仿射变换为桥梁来建立欧氏空间下的摄像机坐标系与世界坐标系之间的变换关系，它与OpenGL等当前流行的图形渲染工具一致，具有更强的通用性；采用基于分类的自然特征匹配策略，能够在视角和视点发生大幅度变化情况下依然正常工作；提出基于特征点集合的仿射坐标系定义方法，使增强现实系统在最小配置下只需4点追踪成功即可完成注册，比需要6点的透视投影方法具有更好的健壮性和精确性。

Because the temperature along the pipeline is not a constant, it changes the velocity of the negative-pressure-wave; the Romberg algorithm of numeric integral and the searching for algorithm are emloyed to locate the leakage.Multi-scale decomposition and reconstruction of wavelet transform is applied 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 Δt in location formula, and the location accuracy is improved.

利用小波变换的多分辨分析和重构技术，对采集到的管道发生泄漏时产生的负压波信号进行了消噪处理；并利用小波变换技术对信号奇异点快速、准确的识别能力，对经过消噪处理后的负压波信号进行了奇异点捕捉，准确确定了定位公式中上、下游站点采集到的负压波奇异点的时间差△t，从而提高了定位的精度。

A detection method of double-threshold constant false alarm movement object on double-base synthetic aperture radar includes finalizing distance compression of various pulse-sampling, dividing orientation time to be multiple CPI, carrying out FFT in each CPI to enter orientation frequency domain, comparing data amplitude of frequency channel at external of clutter region with the first threshold and outputting point trace, making coagulation on point trace, making Hough transform in point trace domain and making decision of the second threshold.

本发明涉及一种用于双基地合成孔径雷达的双门限恒虚警运动目标检测方法，其特征在于：1对每个脉冲采样完成距离压缩；2把方位时间分割成多个相干处理间隔；3在每个CPI内做快速傅立叶变换进入方位频域；4把杂波区外的频率通道的数据幅度和第一门限比较做判决并输出点迹；5点迹凝聚；6在点迹域做Hough变换并做第二门限判决。

In every period, do the following operations:# For each 8*8 block, do the discrete cosine transform, then take out direct current coefficient in each block, using the transformation above for each DC coefficient, the gold stands for the code of the spread-spectrum we use when embedding the different watermark bit in different frames, after all of the watermark information which we want to embed is embedded, then do the inverse discrete cosine transformation, and store the current frame in a new file.

于是利用DCT变换域的这点重要的几何不变性，我们可以推导出一种能够抵抗几何攻击的视频水印算法，即将所需要嵌入的水印信息以127位扩频序列作为辅助，以求和值形式嵌入到DCT变换后的每个宏块的每个DC系数当中，具体嵌入和提取算法如下：根据使用的扩频序列的长度N，基于相关的嵌入器需要选取包含N帧的视频子序列，令这N帧视频子序列作为一个嵌入周期，对于每N帧视频子序列做如下的操作，#即对于每个8×8的像素块进行DCT变换，然后取出每个DCT变换后的直流分量，对于每个DC系数，做如上所述的变换，其中gold为在第k帧中嵌入第i位水印信息时使用的扩频码字值，待将所有需要嵌入的水印信息全部嵌入后，再做反DCT变换，保存当前帧。

Then, an optimization algorithm is used to optimize the initial projective transformation matrices by using area around each feature point, and complete the precise image mosaics.

方法的具体实现为：首先利用相位一致方法提取各图像中边缘上的角点特征，对特征角点进行初始匹配，然后利用初始匹配的角点计算变换矩阵的初始参数，再以光强度差的平方和为优化目标函数，在优化的过程中逐步获得变换矩阵的最佳参数，最后对重叠区域运用渐入渐出的方法实现了光强或颜色的自然过渡。

Firstly, based on the force acting on a single-particle, establish a discriminant formula of the sand threshold, and prove that the sand threshold belongs to the cusp catastrophe. Then establish the basic equation of the cusp catastrophe using coordinate transformation and catastrophe theory. Finally, while particle Reynold number and equivalend diameter are the state variables and Shields parameter is the control variables, we can obtain the model of cusp catastrophe of sand threshold, putting those variables into the basic equations of the cusp catastrophe. The model is derived from the mathematics, which has a certain mathematical theory foundation.

首先从单颗沙粒受力分析出发，建立沙床沙粒起动条件判别公式，进而证明了风沙起动属于尖点型突变；然后通过坐标变换和突变理论建立了尖点突变的基本方程；最后本文选择颗粒雷诺数和等效粒径作为控制变量，希尔兹参数作为状态变量，并把它们代入尖点突变的基本方程，经过拓扑变换得到风沙起动的尖点突变模型，并与前人的公式及实验数据进行比较。

The time-domain characteristic point and change of signal saltation edge of pulse signal were examined, according to the relationship between wavelet zero-crossing and signal saltation edge.

方法根据小波变换过零点和信号突变点之间的关系，分别运用小波变换过零点表征检测脉象时域特征点和各特征点脉搏信号变化的快慢。

Then the structure unit of hexangular lattice is found according to the principle of invariable symmetry. Renormalization transformation is processed when we regard the structure unit and the growth model as graphs before and after transformation respectively. After choosing the11thermodynamic function fugacity as parameter, we can write out the partition functions before and after transformation and the formula of renormalization transformation. At the same time, we also work out the fixed points of transformation.

然后根据对称性不变的原则，从整体晶格中选取结构单元，把结构单元和生长模型分别作为重整化变换前、后的图形来进行重整化变换，选取热力学函数易逸度为参量，写出了重整化变换前后的配分函数和重整化变换关系式，求出了这一变换的不动点。

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。

The split between the two groups can hardly be papered over.

这两个团体间的分歧难以掩饰。

This approach not only encourages a greater number of responses, but minimizes the likelihood of stale groupthink.

这种做法不仅鼓励了更多的反应，而且减少跟风的可能性。