无穷远平面

The numerical algorithm based on theories of projecting and Laguerre,such as homology,circular points and ω of absolute conic is established,an iterative elimination method is applied to boost the nonlinear problem solving.

通过调和射影及Laguerre定理的推论求解出平面圆环点的共轭虚像，利用平行六面体照片存在的三对圆环点的虚像，构造对无穷远平面绝对二次曲线的像ω的约束，使用辗转相除法求解非线性问题。

We systemically discuss how to uniquely decide an infinite plane homography matrix by using the structure information in scene and how to evaluate a homography matrix which convert affine reconstruction to Euclidean reconstruction by solving absolute conic images.

系统地讨论了如何利用场景中的结构信息，来唯一地确定无穷远平面的单应矩阵，进而由射影重构恢复仿射重构，以及如何通过绝对二次曲线的像求解将仿射重构变换为欧氏重构的单应矩阵。

In the first part, depending on three or more images, the main research work are listed as follows:(1) using SVD decomposition to realize projective reconstruction;(2) realizing camera self-calibration by solving Kruppa's equation;(3) recovering Euclidean reconstruction from projective reconstruction. Depending on only two images, the main researches are:(1) making out infinite plane homography matrix by using scene structure information, then recovering affine reconstruction from projective reconstruction;(2) making out the absolute conic images by using scene structure information, and then recovering Euclidean reconstruction from projective reconstruction.

在第一部分中，针对三幅及三幅以上的图像，主要研究：①利用矩阵奇异值分解实现射影重构，②通过求解Kruppa方程实现摄像机自标定，③由射影重构恢复欧氏重构；针对只有两幅图像的情况，主要研究：①利用场景结构信息求解无穷远平面的单应矩阵，由射影重构恢复仿射重构，②利用场景结构信息求解绝对二次曲线的像，由仿射重构恢复欧氏重构。

According to the stability of vanishing points of the projected lines on the image of a group of lines at infinity,the algorithms for camera calibration and indoor visual navigation of the autonomous mobile platform based on parallel s are proposed.

根据一组空间直线上的无穷远线素集在视平面上所形成的消失点对直线的平移具有稳定性的特点，提出了基于平行线的摄像机参数标定和自主移动平台室内视觉导航算法。

We analyze the essence of affine reconstruction and prove the sufficient conditions that a reversible matrix can be an infinite plane homography matrix and we can not uniquely decide an infinite plane homography matrix from fundamental matrix.

详细分析了仿射重构的本质，证明了可逆矩阵为无穷远平面单应矩阵的充分条件，以及从基本矩阵无法唯一确定无穷远平面单应矩阵。

At last, the isochronous center of infinity of a class of quintic systems is studied and all conditions of center and isochronous center are obtained for infinity of this system, which is the first time for the research on the isochronous center of infinity.

最后，研究了一类实平面五次系统的无穷远点的等时中心，给出了系统无穷远点为中心和等时中心的全部条件。这是迄今对无穷远点等时中心进行的首次研究。

Secondly, in the determination of the homography of the plane at infinity, it relies neither on projective reconstruction nor on the homography of a space plane, it needs only some image correspondences and epipoles, which are basic requirements for any camera self-calibration technique.

该方法主要优点在于：在确定无穷远平面的单应性矩阵的过程中，不需要射影重构，也不需要有限远平面信息，唯一所需要的信息是图象极点，从而简化了文献中现有的算法。

In addition, we prove that for a given set of camera motions such as {(R,t1),(R,t2)},if (t1 ,t2) are not linearly dependent, then the homography of the plane at infinity under this motion set can be linearly and uniquely determined.

另外同时给出了由极点确定关于无穷远平面单应性矩阵的充分必要条件。

That is because the model is based on the ideal situation to presume the viewpoint as infinitely far away from the target. So it doesn't include the information of projection plane changing.

这是由于传统的模型是基于二维的平面运动模型，假设为投影点无穷远的情况，并不包含三维透视投影平面变化的信息，因此不能处理。

This paper studies the global topological structure of a kind of plane homogeneous fifth system with three special direction Suppose the system has are only one finite singular point (0,0), then we can assume b50=0, which special directions are determined by equation G=0, introduce Poincare transformation to discuss infinite singular points, according to the coefficient conditions, list all possible infinite singular points and special directions, judging their type, drawing out all kinds of phase portraits when it has three special direction.

研究了一类平面齐五次系统当其只有唯一的有限远奇点且具有三对特殊方向时的全局拓扑结构及系数条件。假设系统只有唯一的有限远奇点(0，0)，不妨设b50=0其特殊方向由示性方程G=0给出，引进poincare变换研究无穷远奇点，再根据定理中的系数条碎，列出系统所有可能的无穷远奇点和特殊方向，并判断其类型，由此画出系统具有三对特殊方向时的全局相图。

Cynanchum Lingtai apricot production in the average weight 65 grams, the brightly-colored fruit, juicy rich, sweet-sour taste, sweet from the nucleolus, when the late Qing Dynasty famous Shaanxi, Gansu provinces, the Qing imperial court Tongzhi tribute for years.

灵台生产的牛心杏平均单果重65克，果实色泽鲜艳，汁多味浓，甜酸适口，离核仁甜，清末时就驰名陕、甘两省，清同治年间曾为朝廷贡品。

Chenopodium album,Solanum nigrum, and Amaranthus retroflexus were very susceptible to the herbicides. Polygonum persicaria and Abutilon theophrasti were relatively less susceptible to the herbicides, and Lycopersicon esculentum was not susceptible to it. The relationship between reduction rates of weed biomass and PPM values of weed leaves 2,4, and 6 days after treatment was established.

供试的6种杂草对该混剂的敏感性存在显著差异：红心藜Chenopodium album、龙葵Solanum nigrum和反枝苋Amaranthus retroflexus对该混剂最敏感，ED90值分别为47.65、71.67和29.17g/hm2；春蓼Polygonum persicaria和苘麻Abutilon theophrasti敏感，ED90值分别为96.91、114.20g/hm2；而番茄不敏感。