投影

Back projection display apparatus includes an optical engine, and display screen of back projection.

一种背投影显示装置及其背投影显示屏幕，背投影显示装置包括一光学引擎与背投影显示屏幕，光学引擎所提供的影像光束透过背投影显示屏幕显示影像。

Whereas parallel projections are used to project points onto the image plane along parallel lines, the perspective projection projects points onto the image plane along lines that emanate from a single point, called the center of projection.

与平行投影沿着平行线将物体投影到图像平面上不同，透视投影按照从投影中心这一点发出的直线将物体投影到图像平面。

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。

This paper established a new kind of relation on projection——conic projection analogue by introducing the latitude circle and longitude circle analogues, then discussed the best choice of the conic vertex angle in this projection, and found the mathematical model and the applicable scope of this projection.

摘 要：本文通过引入类纬圈和类经圈，建立了一种新的投影关系——类圆锥投影，进而探讨了类圆锥投影中圆锥顶角的最佳选择，找到了类圆锥投影的数学模型和适用范围。

According to their processes of construction, the projection methods are classified into three types in the present paper, namely, the Helmholtz-Hodge decomposition projection methods, the operator splitting projection methods and the local continuous projection methods.

本文根据投影方法的构造思路，将众多的投影方法分成了3类，即： Helmholtz-Hodge分解类投影方法、算子分裂类投影方法和局部连续投影方法，并详细的介绍了3类投影方法的发展历程和求解步骤。

The first section is descriptive geometry, including basic knowledge of cartography and projection, projections of point, beeline, plane and their interrelations, projection transformation, curve, curving plane, the projection of curving plane solids, line of section, line of intersection, section and segmentation, elevation projection, dimetric projection.

第一部分为画法几何：其中有制图基本知识，投影的基本知识，点、直线、平面的投影及它们之间的关系，投影变换，曲线、曲面及曲面立体的投影，截交线与相贯线，剖面图与断面图，标高投影，轴测投影等。

We expect it will benefit the industry field to break through the optical measuring limits at present by offering some new ideas. Optical measuring research based on moire interferometry has developed for several decades. The main idea of this research is to utilize the moire effect caused by two superimposed gratings of identical or similar spatial frequency. One is the reference grating and it is a virtual grating created by a computer program in this research; The other grating is the image of grating projected on the measured surface by the DLP projector, and this grating will distort because of the different sloped profile of the surface. To superimpose the program-created grating and the captured distorted grating will derive the so-called moire effect. This research combined the basic theory of optical interferometry and moire effect to project the different phases of the projected grating fringes by the phase-shifting method and compute the principal value of arguments between -π,π. In the end, the phase unwrapping program based on discrete Fourier transform of solving PDEs is used to unwrap the phase of the measured surface, and finally the surface profile is derived by the optical measuring system.

以叠纹干涉术为基础的光学检测研究之发展早已行之有年，而在本研究中所采用的投影叠纹法(Projection moiré)之主要精神在於藉由两道空间频率相近或相同的光栅相互叠加而成的效应，其中一道为参考光栅，而本研究中的参考光栅是以程式产生可调整不同空间频率的虚拟光栅；另一道则为投影至待测物表面的光栅影像，而在起伏高度不一的待测表面上的光栅影像会受到待测物表面起伏状况不同而在观测方向产生光栅投影条纹影像的歪曲变形，将电脑产生的参考光栅与由影像撷取装置所获取投影於待测物表面的光栅影像作叠合，便会产生所谓的叠纹效应；利用基本的光学干涉理论与叠纹效应结合，本研究中以相移法来改变投影於待测表面的光栅相位，再以相移法的理论反运算出在带有待测面各点高度资讯之介於-π，π相位主幅角，再以离散傅立叶转换解偏微分方程的相位重建程式还原待测面的相位值，以得知待测面之表面轮廓。

This paper studies and analyses the map projection transformation, using VC ++ programming language to realize three projection transformation: inclined position projection, Mercator projection and Gaussian M- Ke Lvge projection, and makes the application tests.

本文对地图投影变换做了尝试性的分析研究，利用VC++编程语言实现了斜轴等积方位投影、墨卡托投影和高斯-克吕格投影三种投影变换，并做了应用测试。

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The absorption and distribution of chromium were studied in ryeusing nutrient culture technique and pot experiment.

采用不同浓度K2CrO4(0，0.4，0.8和1.2 mmol/L)的Hoagland营养液处理黑麦幼苗，测定铬在黑麦体内的亚细胞分布、铬化学形态及不同部位的积累。

By analyzing theory foundation of mathematical morphology in the digital image processing, researching morphology arithmetic of the binary Image, discussing two basic forms for the least structure element: dilation and erosion.

通过分析数学形态学在图像中的理论基础，研究二值图像的形态分析算法，探讨最小结构元素的两种基本形态：膨胀和腐蚀；分析了数学形态学复杂算法的基本原理，把数学形态学的部分并行处理理念引入到家实际应用中。