Development of a geometric model for an all-reflective camera system     

《ISPRS Journal of Photogrammetry and Remote Sensing》2013

Currently in photogrammetry conventional camera optics, which are based on a combination of lenses, are solely used. These systems are also called refractive systems. The usage of refractive systems implies a general drawback for some applications. Due to the chromatic aberration of lenses, i.e. slightly different imaging functions for different spectral bands, a significant loss of image quality and geometric accuracy has to be accepted. This fact is important especially for applications that require imaging a wide spectral range. Conventional cameras are not able to satisfactorily capture the ultraviolet or near infrared spectral range in addition to the visible.These chromatic aberration problems can be completely be avoided in all-reflective optical systems, i.e. camera objectives which are completely based on mirrors. The paper will briefly describe the developed all-reflective optical systems designed for optical metrology purposes.A general disadvantage of the design of normal or wide angle all-reflective systems is the asymmetry of the mirror arrangement, which leads to large asymmetric geometric image distortions. These distortions cannot be modeled with standard methods of photogrammetry. Furthermore, the complete system is also more sensitive to local deviations from the ideal mirror surface. Therefore we developed a suitable geometric model, which is adapted to the special case. The model is based on the collinearity condition, extended by a specific additional parameter set optimized with regard to the characteristics of an all-reflective unobscured system. We will show various model variants based on the additional parameter sets of Brown, Ebner and Grün as well as Legendre polynomials, Chebyshev polynomials and Fourier series. The paper discusses the potential of these models to correct the distortion of an all-reflective unobscured optical system prototype based on four aspherical mirrors on the basis of test field self-calibration and describes different approaches to consider local deviations from the nominal aspherical mirror surface with the help of the finite elements method.  相似文献   

非量测数码相机内方位元素测量研究     

喻忠伟;王金鑫 《东北测绘》2013,(2):67-68,72

阐述了非量测数码相机内方位元素的概念、测定的原理和方法,以及在成像过程中产生误差的来源。使用共线条件方程的基本原理,选取合适的模型,利用澳大利亚墨尔本大学的Australis软件解算得到内方位元素,并分析结果的可靠性。  相似文献   

天绘一号卫星无地面控制点摄影测量关键技术及其发展历程   总被引：4，自引：0，他引：4  

王任享 《测绘科学》2013,38(1):5-7,43

本文介绍了天绘一号卫星立项前的预先研究和试验工作、摄影测量研究历程框架以及关键的学术思想。EFP多功能光束法平差结果表明:无地面控制点目标定位精度达到工程技术指标,并与美国SRTM相对精度相当。此外,笔者还简要地介绍了国外主要传输型卫星无地面控制点摄影测量历程。  相似文献   

多面阵数字航摄仪地面检校方法     

齐艳青  李英成  刘晓龙  徐斌 《测绘科学》2013,38(1):13-15

多面阵数字航摄仪具有高分辨率和大幅面覆盖能力的特点,平台检校是其中关键的一步。本文针对多面阵数字航摄仪的特点,通过公式推导,提出了一种计算地面检校初值的方法,并经过数据测试证明该方法能快速得到较为稳定的相对外方位元素。  相似文献   

Camera calibration from profile of revolution     

Zheng Shunyi  Yang Ling  Sun Mingwei 《地球空间信息科学学报》2013,16(1):38-44

This paper focuses on the problem of calibrating a pinhole camera from images of profile of a revolution. In this paper, the symmetry of images of profiles of revolution has been extensively exploited and a practical and accurate technique of camera calibration from profiles alone has been developed. Compared with traditional techniques for camera calibration, for instance, it may involve taking images of some precisely machined calibration pattern (such as a calibration grid), or edge detection for determining vanish points which are often far from images center or even do not physically exist or calculation of fundamental matrix and Kruppa equations which can be numerically unstable, the method presented here uses just profiles of revolution, which are commonly found in daily life (e. g. bowls and vases), to make the process easier as a result of the reduced cost and increased accessibility of the calibration objects. This paper firstly analyzes the relationship between the symmetry property of profile of revolution and the intrinsic parameters of a camera, and then shows how to use images of profile of revolution to provide enough information for determining intrinsic parameters. During the process, high-accurate profile extraction algorithm has also been used. Finally, results from real data are presented, demonstrating the efficiency and accuracy of the proposed methods.  相似文献   

Rapid texture mapping from image sequences for building geometry model     

Zhang Zuxun  Wu Jun  Zhang Jianqing 《地球空间信息科学学报》2013,16(3):8-15

An effective approach, mapping the texture for building model based on the digital photogrammetric theory, is proposed. The easily-acquired image sequences from digital video camera on helicopter are used as texture resource, and the correspondence between the space edge in building geometry model and its line feature in image sequences is determined semiautomatically. The experimental results in production of three-dimensional data for car navigation show us an attractive future both in efficiency and effect.  相似文献   

Calibration of digital camera integration accuracy for low-cost oblique aerial photogrammetry     

Likun Liu  Zhenfeng Shao 《地球空间信息科学学报》2013,16(2-3):90-96

This work describes a calibration process for inexpensive consumer cameras integrated into a low cost and compact aerial multi-view imager for remote sensing and photogrammetry. The main advantage of this design is to make the filming component lightweight and rapidly deployable, as well as reducing cost when compared with mainstream commercial oblique imagery. An in situ flight test was carried out in Guiyang. In that experiment, a meridian convergence-based approach was adopted to adjust preprocessing, the residue error and the captured images’ exterior orientation linear and angular parameters were calculated by means of the direct geo-referencing approach yielding a favorable outcome for exterior orientation linear parameters of the camera, around 0.2–0.3 m deviation from the actual measured results at 1000 m flight above ground level. The camera’s exterior orientation angular parameters φ, ω whose difference compared with the standard aerial aero triangulation approach reached a high accuracy level within the intended endurance of 0.005°. These results indicate that the compact implementation of the oblique aerial imager comprised of consumer level off-the-shelf digital cameras achieved competitive accuracy at a low cost and high versatility.  相似文献   

A New Bolide Station at the High Tatra Mountains     

Jan Svoren  Pavel Spurny  Vladimir Porubcan  Zuzana Kanuchova 《Earth, Moon, and Planets》2008,102(1-4):253-256

The European Fireball Network (EN) is operating since 1963 and one of its stable stations, from the very beginning, is the station at the Skalnate Pleso Observatory in the High Tatras. The station is sited at a height of 1788 m. More than 2900 expositions has been made at the Skalnate Pleso station since 1964 and among them one significant and spectacular event was recorded––bolide Turji-Remety in 2001 followed by a fall of about 450 kg meteorite (Spurny and Porubcan [in: Warmbein (ed.) Asteroids Comets Meteors, 2002]). A systematic search for the meteorite was unsuccessful. The new station having an ideal horizon will be operating since July 2007 on the top of Lomnicky Stit (2636 m above the sea level). This station will be equipped with an Autonomous Fireball Observatory of the Astronomical Institute of the Czech Academy of Sciences, which are already utilized in the Czech part of the EN for several years.  相似文献   

Assessment of the UV camera sulfur dioxide retrieval for point source plumes     

Marika P. Dalton  I. Matthew Watson  Patricia A. Nadeau  Cynthia Werner  William Morrow  Jeremy M. Shannon 《Journal of Volcanology and Geothermal Research》2009

Digital cameras, sensitive to specific regions of the ultra-violet (UV) spectrum, have been employed for quantifying sulfur dioxide (SO₂) emissions in recent years. The instruments make use of the selective absorption of UV light by SO₂ molecules to determine pathlength concentration. Many monitoring advantages are gained by using this technique, but the accuracy and limitations have not been thoroughly investigated. The effect of some user-controlled parameters, including image exposure duration, the diameter of the lens aperture, the frequency of calibration cell imaging, and the use of the single or paired bandpass filters, have not yet been addressed. In order to clarify methodological consequences and quantify accuracy, laboratory and field experiments were conducted. Images were collected of calibration cells under varying observational conditions, and our conclusions provide guidance for enhanced image collection. Results indicate that the calibration cell response is reliably linear below 1500 ppm m, but that the response is significantly affected by changing light conditions. Exposure durations that produced maximum image digital numbers above 32 500 counts can reduce noise in plume images. Sulfur dioxide retrieval results from a coal-fired power plant plume were compared to direct sampling measurements and the results indicate that the accuracy of the UV camera retrieval method is within the range of current spectrometric methods.  相似文献   

面阵数码航摄像控测量布设的思考     

张惠军 《地理空间信息》2012,10(4):112-114

对在像控测量布设中遇到的2个问题进行了阐述,得出航线网精度估算式仍然适用,但数码航摄仪的像控点数量应多于光学航摄仪的结论。另外,在满足一定的条件下可进行跨航线布点,像控点的选点目标需要顾及成图精度要求,不能照搬现有规范要求。  相似文献