透视投影

On the basis of the properties of central projection and orthographic projection, the differences of different rectification approaches based on orthographic projection are explained, and it is suggested that oblique-plane-rectified photograph can produce orthographic representation of flat terrain cover; differential rectification of RS imagery based on DEM can produce orthographic representation of waved terrain cover; and true orthographic rectification based on digital ground-object model can produce orthographic representation of single objects on ground.

根据中心投影和正射投影的特点，从理论上说明了不同正射投影纠正方法之间存在的差异，认为：基于透视变换的像片倾斜纠正可生成水平地表覆被的正射投影表达；基于DEM的正射影像微分纠正可生成起伏地表覆被的正射投影表达；基于数字地物模型的真正射纠正可生成独立地物的正射投影表达。

In this paper, a series of lunar map projection formulas are deduced including azimuthal projections, cylindrical projections and conical projections. The lunar map projections software is compiled. By caculating lunar map projection distortions, their projection distortion rules are found. Base on the lunar exploration mission, the lunar map projection scheme is given in this paper. The azimuthal conformal projection or the circumcenter perspective azimuthal projection is usually used in small areas, especially in two poles. When the whole map of the moon is needed, the azimuthal conformal projection or the circumcenter perspective azimuthal projection is used within 10° in the poles, and the traverse tangent cylindrical conformal projection or the normal secant conical conformal projection can be used in else areas, furthermore, band-division is necessary to reduce the projection distortion.

本文推导了基于月球参考球的各种投影公式，主要包括方位投影、圆柱投影和圆锥投影；编制了月球地图投影计算软件；对多种月球的投影变形进行了详细的计算，总结分析了各种月球投影的变形规律；结合月球探测的需要，给出了月球投影方案的建议：对于局部的面积较小的投影区域，建议使用等角方位投影或外心透视方位投影；如果绘制月面全图，在两极10°范围内采用等角方位投影或外心透视方位投影，其余区域可以采用等角横切圆柱投影和等角正割圆锥投影，并且要进行分带处理。

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 accelerated algorithm of volume rendering based on textures mapping and the wavelet-based multiresolution volume rendering in network are performed by using OpenGL 3D visualization technique. From the point of view of computer graphics, 3D visualization mechanism of volume rendering based on OpenGL textures mapping is studied, including modelview transformation, projection transformation, perspective division, viewport transformation and the ways to embed textures mapping and blending in above four transformations.

利用OpenGL三维可视化技术实现了本文所提出的基于纹理映射的体绘制加速算法和网络环境下基于小波的体数据的多分辨率体绘制，并从计算机图形学的角度，研究了基于OpenGL纹理映射技术的体绘制的三维可视化流程，包括OpenGL的模视变换、投影变换、透视除法、视区变换，以及纹理的定义、映射与融合等步骤在上述四个变换中的嵌入方法。

Finally, the run-length of data points are extracted by horizontal projection, and the modules corresponding to the run-length are taken to decode.

而拍照所造成条码边界的形变，利用反透视转换(Inverse Perspective Transformation)来校正。最后以水平投影的方式撷取出资料点的长度，转换成对应的模组来进行解码的动作。

Authors made use of shifted perspective, orthographic projection, approximations of axial or lateral projection, and approximations of parallel projection in illustrations depicting the detailed structures of machines and devices.

作者运用等同于移动透视、正投影、近似轴测投影和近似平行投影的画法和文字解说表达出机械、器物等的详细构造。

The surface of the region of interest textured in this manner is perspectively represented in the view such that the position of the slice or projection image can be recognized relative to the region of interest.

将如此结构化的感兴趣部位的表面(22)在视图中透视地显示，使得相对于该感兴趣部位的表面可以看出断面图像或者投影图像(21)的位置。

When representing cubic images, there are more people choose the range of 8 x 8pixel (34.1%, 37.8%) for horizontal projection and one-point perspective, and more people choose the range of 12 x 12pixel (35.4%, 48.8%) for two-point perspective and three-point perspective.

在水平投影与一点透视表现立方体的图像中，较多人选择8像素*8像素的范围（34.1%，37.8%）；在两点透视与三点透视表现立方体的图像中，较多人选择12像素*12像素的范围（35.4%，48.8%），显示出在制作立体图像时，在这些像素范围以上的图形能获得较佳的视认绩效。

Using camera objects in 3DS MAX, the method started from a coordinate transformation of objects in the scene based on principle of binocular stereo vision. Then the method carried out the perspective transformation to create left image and right image respectively.

该方法根据双目立体视觉的原理，利用3DS MAX中的摄像机对象对场景中的物体进行坐标变换和透视投影变换，分别生成左眼视图和右眼视图。

We propose novel methods for both techniques to monitor the surrounding area of a vehicle. For fisheye camera calibration, we proposed a novel photogrammetric calibration method using planar calibration objects together with a distortion model based on the design of the fisheye lens. By minimizing the residual error between observed and predicted image coordinates of feature points, a set of camera parameters that best describe the imaging process of the camera can be obtained.

在鱼眼摄影机校正中，我们提出基於摄影校正法的创新的校正方法，其中利用平面校正物进行鱼眼摄影校正，并以视野失真模型(field-of-view distortion model)作为鱼眼失真模型，透过降低摄影机校正误差进行非线性的摄影机参数最佳化，由已校正的鱼眼摄影机所拍摄的影像皆可经由失真校正将鱼眼影像还原至透视投影影像。

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。