透视投影

Topics include: line generators, affine transformations, line and polygon clipping, splines, interactive techniques, perspective projection, solid modeling, hidden surface algorithms, lighting models, shading, and animation.

章节中包含：线的生成，仿射转换，线和多边形的裁切，样条线，互动技术，透视投影，实体模型，隐藏面算法，明暗模型，阴影，和动画。

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。

More complicated perspective projections can be composed by combining this one with rotations, scales, translations, and shears to move the image plane and center of projection wherever they are desired.

更加复杂的透视投影可以是与旋转、缩放、平移、切变等组合在一起对图像进行变换。

With the constraints of these feature points, perspective projection, coplanarity and colinearity, the curved surfaces can be recovered by minimizing the linearly constrained quadric objective function.

把特征点的位置、共面、共线、透视投影等作为约束，通过最小化线性约束下的二次目标函数实现曲面重建。

Research on calibration of cameras based on cross ratio invariability ;2. Firstly,order radial lens distortion parameters are computed by using cross ratio invariability .

该方法利用透视投影的交比不变性原理标定镜头的畸变系数，基于摄像机成像的单应性矩阵及内部参数的基本约束，线性标定出其他摄像机参数。

Vessel foreshortening in angiographic images may cause errors in the assessment of lesions or the selection and placement of stents, and can be influenced by the viewing angles.

在造影图像中，由于透视投影成像导致的血管缩短会引起血管狭窄估计及支架选择和放置错误，而血管缩短与造影角度的选择有关。

The accurate selecting of homonymous points has two situations: when labels exist in the scene, the label's central coordinate is obtained as the homonymous points; and when there are no labels in the scene, all points are firstly displayed in perspective projection's way in the OpenGL environment, and then the homonymous points are selected by man-machine interaction.

同名点的选取分为两种情况：当场景中有标签时，本文提取了标签的中心作为同名点；当地理场景中不存在标签时，本文将两站点云以透视投影的方式在OpenGL环境中显示出来，然后通过人机交互选择的方法获得同名点。

The intersection point S between this line and the plane is the perspective projection of that point.

这条直线与平面的交点S就是点P的透视投影。

By using projective geometry and camera intrinsic parameters and calculating the distance between ship and landmarks, a method of locating ship by measuring the distance based on monocular camera machine vision is presented in this paper.

利用透视投影几何关系和摄像机内部参数，计算船舶与各陆标之间的距离，提出一种基于单目机器视觉的船舶测距定位方法。

There is also usually a fourth view, an orthographic or perspective projection of the scene

大多数情况下，还会有第4个视图，即情景的正交投影或透视投影，用户可以调节每个视图的确切参数。

But we don't care about Battlegrounds.

但我们并不在乎沙场中的显露。

Ah! don't mention it, the butcher's shop is a horror.

啊！不用提了。提到肉，真是糟透了。