中英文资料外文翻译文献
附录1
数字摄影测量的发展与展望
由于新一代传感器、定位系统的迅速发展与应用,以及数字摄影测量工作站的发展及其大规模的推广,这样对摄影测量自身发展提出一个非常严峻而又现实的问题:摄影测量向何处去? 除了摄影测量与新一代遥感传感器、GIS、GPS 更进一步地结合外,摄影测量自身从理论到实际将如何发展? 还有没有发展前景?
在国际上同样对摄影测量发展提出了“疑虑”,美国Ohio 大学Schenk 教授在其著作《数字摄影测量学》的序言中指出:“摄影测量与猫一样,他们有一个共同的特点,他们都有几次生命,摄影测量的终结已经被多次预测。”但是他对此问题作了明确的回答:“数字摄影测量是一门相对年轻的、并且迅速发展的学科。它的许多基本概念与方法来自影像处理与计算机视觉。但是不管它们对它的影响有多强烈,数字摄影测量还是一门有自己特色的学科。”[Schenk 1999] 。
由20 世纪初期,以纯精密、光机的模拟摄影测量仪器为特征的摄影测量一直持续了半个多世纪,30 年代德国著名的摄影测量学家V. Gruber 指出:“摄影测量是一门可以避免技术的技术”。因为摄影测量的模拟测图仪本身就是一台“模拟计算机”,它直接由输入的像点坐标获得输出的地面坐标。在此期间摄影测量的教学、极少量的科研,除所谓的变换光束理论研究以外,多数是围绕欧洲的几个著名厂商生产的模拟摄影测量仪器进行。到50 年代末数字电子计算机开始进入摄影测量时代,摄影测量的研究领域得到了很大的扩展:如解析法空中三角测量、在线空中三角测量、区域网平差、粗差检测理论、正射纠正、数字测图等。90 年代随着数字摄影测量时代的到来,相对于传统的模拟、解析摄影测量,其最大的特点是将计算机视觉、模式识别技术应用到摄影测量,实现了内定向、相对定向、空中三角测量、DEM 生成等的(半) 自动化。数字摄影测量不仅仅将传统摄影测
量仪器各种功能全部计算机化,提高了工效,降低了对作业员的要求,而且正在不
断地扩充摄影测量的功能。但是我们必须清醒地认识到: ①一些数字摄影测量工作站(DPW) 只是解析测图仪的替代品[ HeipkeC. 2001 ] ; ②目前的DPW主要只
适合于航空、航天摄影测量, 而近景、地面摄影测量与它有很大差异(Mikhail E.M. 等2001 ,p. 251) ,将数字摄影测量适应于近景摄影测量,摄影测量的理论
必须进一步发展;③即使是当前自动化程度较高的DPW,摄影测量的主要研究也还
仅仅是在“同名点”的影像匹配技术上(Major R&D efforts were spent on image matching tech2niques ?) (Heipke C. 2001 ,p. 35) 。这就是说,DPW虽然对
摄影测量生产、教学产生了飞跃的发展,但是在理论上除了初步解决“用计算机
代替人眼观测同名点”以外,摄影测量本身在理论上并没有太大的实质性发展。
作者认为:由于用计算机代替人眼观测,我们必须跳出传统摄影测量的束缚,
必须根据计算机的特点考虑数字摄影测量的理论发展,这样就使数字摄影测量为
其理论与实践的发展提出了崭新的契机,例如:
1) 灭点(Vanishing points) 理论与应用
众所周知:灭点是空间一组平行线的无穷远点在影像上的构像,即该组平行
线在影像上的直线影像的交点,我们可以认为该空间的无穷远点与对应的灭点是
一对“对应点”,它们满足共线方程。例如：航空影像,除“底点”(空间一组铅
垂线的灭点) 位于影像内,一般它不是“明显点”,其他的“灭点”多数位于影像外。当航空影像接近水平时,水平方向的灭点几乎在“无穷远”处。因此在模拟、解析摄影测量中,灭点不可能有任何实用意义,除了其定义外,它的理论也没有多
少研究。但是,在数字摄影测量、计算机图形学中,对空间平行线的自动分类、灭点的提取、应用是一个重要的研究方向,它不仅仅是利用单张非量测相机所获得
的影像进行建筑物三维重建的基础(张祖勋等2001 ,Cipolla R. etc. 1999) ,
而且它将成为利用城市大比例尺地形图进行空中三角测量控制的信息,并被用于
城市大比例尺地形图的数据更新。
2) 广义点(Generalized points) 理论与应用
由于摄影测量渊源于测量学中“测点”的“前方交会”与“后方交会”,因
此共线方程(即物点、像点与摄影中心位于一条直线上) 是整个摄影测量的核心。但是在建筑物的提取、建筑摄影测量、工业零件测量中,大量存在的是“直线”,由此,基于直线的摄影测量(即“共面方程”) 得到了深入的研究与应用(F. A.Van. den Heuvel ,1999 等) 。但是在现实世界中,还存在大量的“曲线”,例如地面
上的道路、河流、湖泊等,建筑测量、工业测量中的园、圆弧、曲线等。另外,
在实际生产(特别是利用影像进行地图修测) 中,目前一般是要在地形图与影像
之间确定对应“点”作为控制,这是一项比较困难的任务。因为,一般情况下明显点: 独立点( dot point ) 、角点( cornerpoint) 较少,并也难以精确“配准”,因此能否利用地图与影像上存在的大量的“线”作为控制信息进行配准,将具有重大的理论与现实意义。为此作者提出了“广义点”理论。在传统的摄影测量中的“点”: 指的是“物理”意义上(或称为“可视”) 的点,而广义点则是“数学”意义上的点,因为任何一条“线”都是由“点”组成。由“广义点”理论:曲线(或直线) 上任意一个点都可以被用为“控制点”,而且可以直接应用“共线方程”,但是只能在两个( x 、y) 共线方程中选取一个。因此我们很容易将点、直线、园、圆弧、任意曲线归纳为一个数学模型:共线方程,进行统一平差。
3) 多基线立体(Multi - base stereo)
到目前为止,人都是由一条眼基线的“双眼”感受3 维世界,而摄影测量(无论是模拟、解析、数字摄影测量) 多是沿用“由1 条基线、2 张影像,构成的一个立体像对”进行测量。但是进入数字摄影测量时代,我们将利用计算机“匹配”替代“人眼”测定影像同名点,这要求构成立体像对的“交会角”愈小愈好,才能使匹配的可靠性愈高,由此产生了“多目立体匹配”(章毓晋2000) 。为解决周期性重复特征所引起的误匹配,计算机界提出了对倒距离的SSD (Sum of Square Difference) 求和(Okutomi 1993) 。但是从测量的交会的误差理论而言,“交会角”愈小,精度愈低,由此要求对于“多目立体匹配”,摄影测量界可利用众所周知的空中三角测量原理,对多度重叠点进行“多方向的前方交会”,既能较有效地解决任意的误匹配问题, 又能满足测量精度要求。多基线立体(multi - base stereo) 对于数字近景摄影测量十分重要,对于数码航空摄影(如Zeiss 的DMC) 的大重叠影像同样具有重要的应用前景。
附录2
Future Development and Prospect of Digital Photogrammetry
As a new generation of sensors, positioning system and the rapid development of applications, and digital photogrammetry workstations and the development of large-scale promotion, This right Photogrammetry own development and a very grim reality : Photogrammetry go? In addition to the new generation of photogrammetry and remote sensing sensors, GIS, further integration of GPS, Photogrammetry itself from the theoretical to the practical how? there are no prospects for development? Similarly international development for Photogrammetry the "worries" USA Ohio University Professor Schenk in his book "digital photographic surveying" the preamble : "Photogrammetry and cats, they have one common feature, they have several lives, Photogrammetry has been the end of many forecasts. "But he made this clear answer : "Digital Photogrammetry is a relatively young, and rapid development of the subjects. Many of its basic concepts and methods from image processing and computer vision. But whether they how the effects of a strong, Digital photography is a measurement has its own characteristics of the subjects. "[Schenk 1999].
By the early 20th century, pure sophistication, - ray machine simulation equipment for Photogrammetry characteristics of photogrammetry has lasted more than a half century. Germany's 30 leading scientists Photogrammetry V. Gruber : "Photogrammetry is a technique to avoid the technology." Photogrammetry because Simulation Plotter itself is a "computer simulation" It imported directly from the image coordinates access to the output of the ground coordinates. In the meantime
Photogrammetry teaching, a very small amount of research, in addition to the so-called transform beam theory research, Most of Europe is on several well-known manufacturers of simulation equipment for Photogrammetry. To the late 1950s digital electronic computer has begun to enter the era of photogrammetry, Photogrammetry areas of research has been greatly extended : If analytical aerial triangulation, online aerial triangulation, Regional network adjustment, gross error detection theory, ortho-rectification, digital mapping and so on. 90's, with digital photogrammetry times, and compared to traditional simulation and analytical photogrammetry, its greatest feature is a computer vision, pattern recognition technology to photogrammetry, achieved within orientation relative orientation, Aerial Triangulation, the DEM Generation (semi-) automatic. Digital Photogrammetry not only traditional photographic instrument functions all computerized, high efficiency, lowering of the operating requirements and is continuously expanded photographic measurement. However, we must clearly understand that : ①Some of digital photogrammetric workstation (DPW) is Analytical Plotter substitutes [HeipkeC. 200 1]; ②the DPW mainly suitable for aerospace Photogrammetry and choppy, terrestrial photogrammetry and it has great differences (Mikhail Morgan. others 2001, pp. 251). Digital Photogrammetry will meet in Close-Range Photogrammetry, ISPRS theory must be further developed; ③ even higher degree of automation at present the DPW, Photogrammetry the main research is still only in "the same name point" image matching technology (Major R & D eff orts were spent on image matching tech2niques click ) (C Heipke. 2001, pp. 35). That is to say, although the DPW photogrammetry production, teaching in a leap in the development, However, in theory, in addition to the preliminary settlement "with the computer instead of the same name eyes observation point", Photogrammetry in theory itself is not very substantive development.
The author believes that : due to the use of computers instead of human eyes observation, we must go beyond traditional photogrammetry straitjacket, According to the computer must consider the characteristics of Digital Photogrammetry theory, As a result, digital photogrammetry theory and practice for the development of new opportunities, such as :
1) Vanishing Point (Vanishing points) theory and application is well known : Vanishing Point is room for a group of parallel lines infinite point on the picture of conformation, The group that is parallel lines on the picture of the intersection of linear video, We can think of the space of infinite points with the corresponding Vanishing Point is a "corresponding points", they meet a total equation. For example : aerial images, in addition to "end points" (a group of space plumb line in Vanishing Point) in the image, generally it is not "obvious point", Other "Vanishing Point" in the majority of images outside. When the air close to the level of image, the horizontal direction the vanishing point in almost "infinite" Department. So the simulation, analytical photogrammetry, the vanishing point can be no practical significance, in addition to its definition, Its theory is not much research. However, the digital photography, computer graphics, parallel lines of space automatic classification, the vanishing point of extraction, Application is an important research direction. It is not just the use of non-measurement leaflets camera acquired images for three-dimensional reconstruction of the building foundation (200 Zuxun 1, R Cipolla. etc.. 1999), but it will be the use of urban large-scale topographic maps for aerial triangulation control of the information, was used for large-scale urban topographic map data updates.
2) Generalized points (Generalized points) theory and application of photogrammetry as measured in Origin Science "measuring point" of the "front-line Trade Fair" and "rear Trade Fair", a total of equation (that is, objects, pixels and photography center at a straight line) is a photographic survey of the entire core. However, in building extraction, construction photogrammetry, industrial components measurement, there are a lot of "straight", which, Based on a linear Photogrammetry ( "coplanar equation") is an in-depth study and application (F. A. Van. de n Heuvel, 1999). But in the real world, there is a large number of "curve" on the ground such as roads, rivers, lakes, building surveying, Measurement of the industrial park, arcs, curves. In addition, the actual production (in particular, the use of image maps Surveying), The general is to topographic maps and images corresponding to establish between "point" as a control, and this is a more difficult task. Because, under normal circumstances obvious points : points (dot point). Corner (cornerpoint) less, and are
difficult to accurately "registration" it can make use of maps and images on the number of "lines" as a control for registration information. will be of great theoretical and practical significance. That the author of "generalized point theory." In the traditional photogrammetry "point" : it refers to a "physical" sense (or called "visualization"), and generalized point is the "math" in the sense, because any one "line" is the "point" component. "Generalized point" theory : curve (or linear), an arbitrary point can be used as the "control points" but can be applied directly, "a total equation," but only two (x, y) were selected equation 1. Therefore it is easy to point straight, the landscape, arc, arbitrary curves into a mathematical model : the total equation. unified adjustment.
3) Multi-baseline stereo (Multi-base stereo) so far, people are from a baseline of eyes "eyes" feel three-dimensional world, and Photogrammetry (both simulation and analysis, Digital Photogrammetry) are used "by a baseline, two images, consisting of a three-dimensional, as the" measured. But the digital photogrammetry era, we will use the computer "matching" alternative "eyes" image of the same name, This requires a three-dimensional form, as to the "contact angle" the smaller the better, can match the higher reliability, hence the "multi-purpose stereo matching" (Zhang Yujin, 2000). To address the cyclical repetition of the error caused by the match, Computer reversing the right distance from the SSD (Sum of Square Difference) Summation (Okutomi 1993). But measured from the intersection of error theory, "Rendezvous Point" and conversely, the lower the accuracy, This request for "multi-purpose stereo matching", ISPRS sector can use the well-known aerial triangulation principle, degrees of overlapping spots "over the direction of the intersection in front," can more effectively address the misuse of arbitrary matching, can meet the requirements of measurement precision. Multi-baseline stereo (multi-base stereo) for digital terrestrial photogrammetry important, For digital aerial photography (such as the Zeiss DMC) of overlapping images equally important prospect.