基于移轴成像的数字相机检校方法研究

发布时间：2018-06-17 08:50

本文选题：移轴成像 + 相机检校　；参考：《中国科学院大学(中国科学院遥感与数字地球研究所)》2017年硕士论文

【摘要】：近些年来为了满足多种领域对高分辨率空间数据及信息的迫切需求,在摄影测量领域,数字相机得到了广泛的应用,新型的数字化航空摄影测量系统也不断涌现。移轴相机由于其垂视摄影且视场可扩展的优势,已逐步开始应用于航空大面阵多相机系统中。通过相机检校,可以对测量工作的精度进行分析。相机检校是高精度摄影测量工作的重要保障。针对当前航空移轴大面阵多相机系统未检校或检校精度不高导致几何精度较低的问题,本文提出了一种基于移轴成像原理的数字相机几何检校方法。该方法建立了移轴相机像平面坐标系和基准像平面坐标系,并推导了两坐标系的转换关系,最后以此为基础构建了移轴相机的检校模型。实验表明论文提出的基于移轴成像的相机检校方法,能够满足测绘应用,并可为各种新型的移轴组合相机检校提供方法和思路。本文的主要研究内容和研究成果包括以下三个方面:(1)针对倾斜和平移两种移轴类型,分析了移轴相机的成像原理和特点。通过比较分析可知,平移类型的移轴更适合应用于航测相机。论文通过与倾斜成像作比较,体现了移轴成像的优势:1、通过平移方式的移轴既能够保证传统的中心投影的结构,又能够大大减少倾斜成像所引起的影像形变;2、由于移轴相机视场可扩展,通过多探测器多镜头拼接的成像方式可以实现大视场和宽覆盖、增加基高比和提高作业效率。(2)针对移轴相机的成像方式,建立了移轴影像像平面坐标系和基准像平面坐标系,并推导了两坐标系的转换关系。基于空间后方交会的原理,提出了一种针对移轴相机的检校方法。基于论文提出的移轴相机检校方法,利用室内三维检校场,设计了移轴相机的室内检校场检校实验。基于论文提出的移轴相机检校方法,编写了相机检校和可靠性验证程序,对论文提出的算法进行了验证。实验表明,利用论文提出的移轴相机检校方法对移轴相机进行检校,解算得到的检校参数具有较高的精度。针对检校结果,论文分析了不同移轴量下相机检校参数产生的变化,讨论了移轴量对检校参数的影响,最后通过空间前方交会的方式对检校结果进行可靠性验证。(3)基于移轴相机的成像模型,论文以多面阵移轴组合相机为例,分析了移轴组合相机的成像方式,并对论文提出的移轴相机的检校模型进行了扩展,建立了单面阵CCD像空间坐标系、子相机像空间坐标系和虚拟像空间坐标系,推导三坐标系的坐标转换关系。基于论文提出移轴相机检校方法,提出了针对多面阵移轴相机的子相机的检校方法和子相机之间的检校方法。
[Abstract]:In recent years, in order to meet the urgent needs of high-resolution spatial data and information in many fields, digital cameras have been widely used in the field of photogrammetry, and new digital aerial photogrammetry systems have been emerging. Because of its advantages of vertical photography and extensible field of view, shaft-shifting camera has been gradually applied to aerial large array multicamera systems. The accuracy of measurement can be analyzed by camera calibration. Camera calibration is an important guarantee for high precision photogrammetry. In order to solve the problem that the geometric accuracy is low due to the uncalibrated or the low accuracy of the large plane array multi-camera system, a geometric calibration method for digital camera based on the principle of shaft-shifting imaging is proposed in this paper. In this method, the image plane coordinate system and the reference image plane coordinate system are established, and the transformation relationship between the two coordinate systems is deduced. Finally, the calibration model of the shift axis camera is constructed. The experimental results show that the camera calibration method based on shaft-shifting imaging presented in this paper can meet the needs of surveying and mapping applications, and can also provide methods and ideas for the calibration of various new types of shaft-shifting combined cameras. The main research contents and results of this paper include the following three aspects: 1) aiming at the two types of tilt and translation, the imaging principle and characteristics of the shaft-shifting camera are analyzed. Through comparison and analysis, it can be seen that the shift shaft of translation type is more suitable for aerial camera. Comparing with oblique imaging, the paper shows the advantage of axial shift imaging: 1, and the traditional structure of center projection can be guaranteed by translation. It can also greatly reduce the distortion caused by tilt imaging. Because the field of view of the axial shift camera can be expanded, the large field of view and wide coverage can be realized by multi-detector and multi-lens splicing. The image plane coordinate system and the reference image plane coordinate system are established according to the imaging mode of the axial shift camera, and the conversion relationship between the two coordinate systems is deduced. Based on the principle of space rear rendezvous, a calibration method for shaft-shifting camera is proposed. Based on the calibration method proposed in this paper, an indoor calibration experiment of the shaft-shifting camera is designed by using the indoor three-dimensional calibration field. Based on the calibration method proposed in this paper, the program of camera calibration and reliability verification is developed, and the algorithm proposed in this paper is verified. The experimental results show that the calibration method proposed in this paper has a high accuracy. In view of the results of calibration, the paper analyzes the changes of camera calibration parameters under different shafts, and discusses the influence of axis shifting on calibration parameters. Finally, the reliability of the calibration results is verified by the way of space forward intersection. (3) based on the imaging model of the shaft-shifting camera, this paper analyzes the imaging mode of the moving-axis combined camera by taking the multi-plane array camera as an example. The calibration model of the camera is extended, and the coordinate system of CCD image space, the image space coordinate system of subcamera and the virtual image space coordinate system are established, and the coordinate transformation relationship of the three coordinate systems is deduced. Based on this paper, a calibration method for shaft-shift camera is proposed, and a calibration method for sub-camera of multi-plane array camera and a method for calibrating between sub-cameras are proposed.
【学位授予单位】：中国科学院大学(中国科学院遥感与数字地球研究所)
【学位级别】：硕士
【学位授予年份】：2017
【分类号】：TB852.1

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