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1.
The rational function model (RFM) is widely used as an alternative to physical sensor models for 3D ground point determination with high-resolution satellite imagery (HRSI). However, owing to the sensor orientation bias inherent in the vendor-provided rational polynomial coefficients (RPCs), the geo-positioning accuracy obtained from these RPCs is limited. In this paper, the performances of two schemes for orientation bias correction (i.e., RPCs modification and RPCs regeneration) is presented based on one separate-orbit QuickBird stereo image pair in Shanghai, and four cases for bias correction, including shift bias correction, shift and drift bias correction, affine model bias correction and second-order polynomial bias correction, are examined. A 2-step least squares adjustment method is adopted for correction parameter estimation with a comparison with the RPC bundle adjustment method. The experiment results demonstrate that in general the accuracy of the 2-step least squares adjustment method is almost identical to that of the RPC bundle adjustment method. With the shift bias correction method and minimal 1 ground control point (GCP), the modified RPCs improve the accuracy from the original 23 m to 3 m in planimetry and 17 m to 4 m in height. With the shift and drift bias correction method, the regenerated RPCs achieve a further improved positioning accuracy of 0.6 m in planimetry and 1 m in height with minimal 2 well-distributed GCPs. The affine model bias correction yields a geo-positioning accuracy of better than 0.5 m in planimetry and 1 m in height with 3 well-positioned GCPs. Further tests with the second-order polynomial bias correction model indicate the existence of potential high-order error signals in the vendor-provided RPCs, and on condition that an adequate redundancy in GCP number is available, an accuracy of 0.4 m in planimetry and 0.8 m in height is attainable.  相似文献   

2.
传统的后方交会最小二乘解法需要良好的外方位元素初值。在无初值或者初值不够精确的情况下,最小二乘迭代不容易收敛。在近景摄影测量或者计算机视觉等领域,往往不提供良好的初值,无法适用传统的后方交会解法。针对上述情况,本文提出了一种基于单应性矩阵的后方交会直接解法,在不需要初值的情况下,获取外方位元素的直接解。该方法根据单应性矩阵所描述的平面几何关系,利用单应性矩阵内在的约束条件,将后方交会问题转换为一个二元二次方程组的求解问题。该方法受舍入误差影响小,在无偶然误差的情况下,解算精度能达到10–9量级,能够避免传统直接解法计算复杂的问题,为传统的平差迭代解法提供良好的初值。此外,在多个控制点共面的情况下,该方法能够直接获得外方位元素的精确解。实验结果表明:在各种不同倾角拍摄的情况下,该方法均能够获得稳定的外方位元素,为后续的后方交会最小二乘算法提供良好的初值。采用本文方法计算的初值参与平差,能够达到与人工给定初值平差一致的精度,且迭代收敛速度是人工给定初值平差的2倍以上。在控制点共面的情况下,该方法的反投影精度能够达到亚像素级,且精度优于大部分主流的直接解法。  相似文献   

3.
光学卫星摄影无控定位精度分析   总被引:4,自引:2,他引:2  
王任享  王建荣  胡莘 《测绘学报》2017,46(3):332-337
"全球连续覆盖"和"局部区域覆盖"是卫星摄影测量常用的两种摄影模式,两种模式应用目标和无控定位实现途径也各有特点。本文简要介绍了两种模式典型的卫星无控定位精度情况,阐述了光束法平差的关键技术,重点对前方交会和光束法平差无控定位精度进行试验分析。试验结果表明,姿态误差是影响无控定位精度的重要因素,影像分辨率对其影响较小。当外方位角元素误差大于0.5″时,即使影像分辨率为5m,光束法平差后,其无控定位精度也优于0.5m分辨率影像前方交会精度。  相似文献   

4.
卫星摄影姿态测定系统低频误差补偿   总被引:1,自引:0,他引:1  
王任享  王建荣  胡莘 《测绘学报》2016,45(2):127-130
姿态测定系统不仅存在高频误差,还存在与卫星轨道纬度及时间有关的低频误差,严重影响无地面控制点测量精度。本文分析了产生低频误差的因素及相关解决措施,并在天绘一号(TH-1)卫星工程中,利用光束法平差实现低频误差的自动检测与补偿处理,消除低频误差对定位精度的影响,最后进行了试验验证。试验结果表明:低频误差补偿技术,很好地解决了无地面控制定位系统误差问题,为实现天绘一号卫星全球定位精度的一致性发挥了重要作用。  相似文献   

5.
This paper describes a method for pass processing of IRS-1C/1D imagery acquired by the three CCD arrays of the panchromatic (PAN) camera. It is based on the fact that during a single pass, the image data stream from the three CCD arrays of the PAN camera can be adjusted together as a single image, exploiting the knowledge of the internal geometry and the angular relationships between the CCD arrays. The geometry of this extended image can be rectified with a single ground control point (GCP). A full PAN scene consists of nine subscenes, each with a dimension of 23.5 km×23.5 km. The method is not restricted in the number of continuous full scenes (in the same pass) that can be adjusted. The scale variations between the images from the three detectors are corrected by computing the relative focal lengths of detectors 1 and 3 with respect to detector 2. Two tests were conducted to verify the accuracy of the adjustment procedure. Average root-mean-square (RMS) errors of ±10.5 m in the latitude direction and ±11.3 m in the longitude direction were obtained with a single surveyed GCP and a set of survey points used as checkpoints. The results of the tests show that the adjustment of full PAN scenes, as proposed in this paper, is an effective means of reducing the number of GCPs required for precise determination of ground coordinates.  相似文献   

6.
针对大区域多航带InSAR(干涉合成孔径雷达)影像定位及拼接时缺少GCP(地面控制点)的问题,提出了一种多航带InSAR影像联合定位的方法。该方法借鉴摄影测量中的光束法平差思想,并利用InSAR干涉定标后得到影像上各点高程值。通过对四川绵阳地区的多航带InSAR实际数据的实验,验证了本方法的可行性,且精度达到了各景影像独立校正的水平。分析了控制点数量、位置、重叠区域范围、地形起伏对平差精度的影响,并给出了控制点布放原则。  相似文献   

7.
This paper presents an automatic mosaicking method for generating building facade textures from a monocular close-range digital image sequence. The process begins with the computation of the camera parameters (except the coordinates of the projective center), which are determined by combining vanishing point geometry with constraints of a straight line bundle as well as prior information of parallel lines in object space. The raw images are later rectified for the purpose of eliminating their salient geometric distortion. Next, automatic retrieval of the relevant image segment is implemented using the detecting range variance by means of the histogram of projective differences between the corresponding points for each of the facades from the raw image sequence. A strip model of the least-squares adjustment, which is similar to the strip block adjustment in aerial triangulation, is employed to determine the spatial alignment of each of the image segments in order to generate the facade textures from the relevant image segments. Afterwards, the entire building facade texture is mosaicked by ortho-image generation. Two refining strategies are proposed to optimize the mosaic result. One is refining the mosaic region where corresponding points are difficult to match but plenty of horizontal lines are available, and the constraint of corresponding horizontal lines is introduced to implement this process. The other strategy is to refine the unsatisfactory mosaic region by densifying the corresponding points by means of the spatial alignment of the relevant image segment computed by the strip method. The experimental results indicate that this method is widely applicable and compares well with other reported approaches with regard to automation level and applicability, for uncalibrated images as well as images with large geometric distortions.  相似文献   

8.
ICESat激光高程点辅助的天绘一号卫星影像立体区域网平差   总被引:1,自引:1,他引:0  
无地面控制点(简称无控)区域网平差是实现卫星影像无控测图的一项重要技术,对于境外和外业测控困难区域的测图具有重要意义。然而,无控区域网平差的定位精度一般难以满足对应比例尺测图规范要求。利用公开、可稳定获取的公众地理信息数据辅助区域网平差,是提高卫星影像无控定位精度的有效途径,其中ICESat激光高程点便是一种良好的高程控制数据。为了提高天绘一号卫星影像无控定位精度,本文提出ICESat激光高程点辅助的卫星影像模型法立体区域网平差方法。首先,以30 m分辨率SRTM估算的地形坡度作为限制条件,结合激光高程点自身质量评价信息,自动提取高质量ICESat激光高程点;其次,利用自动匹配的连接点进行模型法自由网平差,实现卫星影像几何定位精度的相对一致性(内部一致性);最后,将激光高程点自动量测至卫星影像作为控制点,其平面坐标根据自由网平差结果前方交会计算而得,高程坐标取自激光点高程,再次进行区域网平差精化定向参数,提高卫星影像的绝对高程精度。最后本文利用山东全省的天绘一号卫星影像进行试验,验证了本文方法的有效性和可行性。  相似文献   

9.
基于GCP库的星载SAR图像自动精校正   总被引:1,自引:0,他引:1  
近年来,合成孔径雷达(SAR)技术已取得巨大进步,人们也越来越重视其潜在的应用前景。但是,雷达侧视成像性质和地形起伏的影响导致SAR图像的几何畸变非常复杂,大大影响了SAR图像的应用。几何精校正是SAR图像广泛应用的前提,但是校正过程中需要大量地面控制点(GCPs),以往的人工选点方法费时费力。本文提出了一种基于控制点自动匹配的控制点选点方法,用以提高点位精度和工作效率。该方法包括纠正区域GCP库的建立和GCP图像片的自动匹配。试验结果表明,该方法具有较好的应用价值。  相似文献   

10.
何敏  何秀凤 《遥感学报》2008,12(1):23-27
针对目前SAR干涉测量中基线估计现存的问题,提出了利用Kalman滤波和配准参数进行基线估计的方法.所提出的方法具有不需地面控制点、不受地形限制和不依赖于轨道参数等优点,并可以估计时变的基线参数.利用南京地区的ERS-1/2 tandem数据进行了试验研究,并对提出的方法进行了验证.结果表明,在精确的卫星轨道数据和地面控制点不能获取时,所提出的方法仍能有效地估计InSAR基线.这在一定程度上补偿了轨道偏移带来的误差,为获取高精度的DEM奠定了基础.  相似文献   

11.
Use of high-resolution and historic CORONA satellite photographs for mapping and other purposes requires Ground Control Points (GCPs), as ephemeris data and image parameters are not available. However, the alterations in landscape in last 34 years (i.e., since the acquisition of these photographs) prevent identification and collection of large number of GCPs in the field. This paper presents a methodology for collection of GCPs for CORONA photographs. The advantages and limitations of the methodology are discussed. For a study site, situated in Siwaliks and Lower Himalayas, the GCPs were identified in CORONA photographs and their WGS84 coordinates were estimated through a process of datum transformation and georeferencing. Estimated GCP coordinates from the topo sheets and 2D and 3D views of photographs, helped in identifying the GCP locations in field, which were observed using DGPS. Investigations were carried out to relate Differential Global Positioning System (DGPS) accuracy with base line length and time of observation. Abase line of 350 km and half an hour observation were found appropriate to yield accuracy in GCP collection by DGPS method, which conforms to CORONA resolution of 3 m.  相似文献   

12.
The major contribution of this paper relates to the practical advantages of combining Ground Control Points (GCPs), Ground Control Lines (GCLs) and orbital data to estimate the exterior orientation parameters of images collected by CBERS-2B (China–Brazil Earth Resources Satellite) HRC (High-resolution Camera) and CCD (High-resolution CCD Camera) sensors. Although the CBERS-2B is no longer operational, its images are still being used in Brazil, and the next generations of the CBERS satellite will have sensors with similar technical features, which motivates the study presented in this paper. The mathematical models that relate the object and image spaces are based on collinearity (for points) and coplanarity (for lines) conditions. These models were created in an in-house developed software package called TMS (Triangulation with Multiple Sensors) with multi-feature control (GCPs and GCLs). Experiments on a block of four CBERS-2B HRC images and on one CBERS-2B CCD image were performed using both models. It was observed that the combination of GCPs and GCLs provided better bundle block adjustment results than conventional bundle adjustment using only GCPs. The results also demonstrate the advantages of using primarily orbital data when the number of control entities is reduced.  相似文献   

13.
In the absence of either satellite ephemeris information or camera model, rational functions are introduced by many investigators as mathematical model for image to ground coordinate system transformation. The dependency of this method on many ground control points (GCPs), numerical complexity, particularly terms selection, can be regarded as the most known disadvantages of rational functions. This paper presents a mathematical solution to overcome these problems. Genetic algorithms are used as an intelligent method for optimum rational function terms selection. The results from an experimental test carried out over a test field in Iran are presented as utilizing an IKONOS Geo image. Different numbers of GCPs are fed through a variety of genetic algorithms (GAs) with different control parameter settings. Some initial constraints are introduced to make the process stable and fast. The residual errors at independent check points proved that sub-pixel accuracies can be achieved even when only seven and five GCPs are used. GAs could select rational function terms in such a way that numerical problems are avoided without the need to normalize image and ground coordinates.  相似文献   

14.
This paper deals with the orientation of three-line imagery which has been taken during the MOMS-02/D2 experiment in spring 1993, and during the MOMS-2P/PRIRODA mission since April 1996. The reconstruction of the image orientation is based on a combined adjustment of the complete image, ground control, orbit and attitude information. The combined adjustment makes use of the orientation point approach or the orbital constraints approach. In the second case, the bundle adjustment algorithm is supplemented by a rigorous dynamical modeling of the spacecraft motion. The results of the combined adjustment using MOMS-02/D2 imagery and control information of orbit #75b are presented. Based on the orientation point approach an empirical height accuracy of up to 4 m (0.3 pixel) is obtained. In planimetry the empirical accuracy is limited to about 10 m (0.7 pixel), since the ground control points (GCP) and check points could not be identified in the imagery with the required accuracy. Computer simulations on MOMS-2P/PRIRODA image orientation based on realistic input information have shown that good accuracies of the estimated exterior orientation parameters and object point coordinates can be obtained either with a single strip and a few precise GCP or even without ground control information, if a block of several overlapping and crossing strips with high geometric strength (q≈60%) is adjusted.  相似文献   

15.
CE-1立体相机与激光高度计数据联合平差   总被引:1,自引:0,他引:1  
赵双明  冉晓雅  付建红  郭秋燕 《测绘学报》2014,43(12):1224-1229
CE-1三线阵立体相机和激光高度计主要用于获取月球形貌信息.CE-1沿轨运动过程中,可同时获取高分辨率的三线阵扫描影像和高精度的激光测高数据.在分析立体影像与激光高度计数据不一致性的基础上,为提高定位精度,将激光测距数据引入三线阵立体影像光束法平差处理.本文提出一种改进的外定向参数模型,采用3阶Lagrange多项式模型(LPM)建立外定向线元素内插模型,采用四元数球面线性内插建立外定向角元素模型,并根据改进模型建立激光高度计数据与影像数据的联合平差数学模型.试验表明,本文立体相机和激光高度计数据联合平差模型是有效的.  相似文献   

16.
用于行星探测车的视觉测程方法已经被广泛研究,但传统的视觉测程方法仅根据相邻的两帧影像进行运动估计,忽略了连续多帧影像间更强的几何约束。本文提出一种新的视觉测程方法,在连续多帧影像间进行特征追踪构成影像网,并用光束法平差进行运动估计。在特征追踪过程中,根据不同立体影像中欧氏距离的一致性剔除离群值,并自适应地选择几何关键帧。用蒙特卡罗方法分析了不同几何配置下视觉测程的精度。野外实验结果表明本文提出的新方法能有效提高探测车定位精度。  相似文献   

17.
ABSTRACT

In this paper, we propose a method to regenerate Rational Polynomial Coefficients (RPCs) using KOMPSAT-3A imagery and to reduce the geolocation error using minimum ground control points (GCPs). To estimate the new RPCs, the physical sensor model fitted to KOMPSAT-3A imagery was utilized and virtual GCPs over the study area were created. The size of the virtual grid used was 20x20x20. To remove the sensor-related errors in physical sensor model, three different image correction models (image coordinate translation model, shift and drift model, and affine transformation model) were additionally applied. We evaluated our proposed method in two areas within Korea, one in urban (Seoul) and one in rural (Goheung) areas. The results showed that there was a significant improvement after applying the suggested approach in the two areas. The image coordinate translation model is suggested in terms of GCP requirement and expected errors estimated from the error propagation analysis using Gauss–Markov Model (GMM).  相似文献   

18.
多影像空三平差辅助下的车载全景相机严密标定方法   总被引:1,自引:0,他引:1  
针对目前全景相机标定方法的研究现状,提出了一种多影像光束法空三平差辅助下的全景相机内参数严密标定方法。首先建立全景相机标定场,对组成全景相机的每台单相机的内参数进行标定;然后按照预先设计好的摄影参数,旋转摄影获取全景相机在标定场中多个不同摄影方向的影像,利用其中一个摄站的标定影像和物方控制点通过空间后方交会的方法解算单相机之间的初始相对方位元素,即粗标定;最后将所有摄站的标定影像构建区域网并进行光束法空三平差,获取精确的全景相机参数,即严密标定。试验表明,文中提出的全景相机标定方法可以提高标定结果的精度和可靠性,为全景影像的拼接、量测及真彩点云的生成等后续研究和应用奠定可靠的基础。  相似文献   

19.
In traditional GPS-supported aerotriangulation, differential GPS (DGPS) positioning technology is used to determine the 3-dimensional coordinates of the perspective centers at exposure time with an accuracy of centimeter to decimeter level. This method can significantly reduce the number of ground control points (GCPs). However, the establishment of GPS reference stations for DGPS positioning is not only labor-intensive and costly, but also increases the implementation difficulty of aerial photography. This paper proposes aerial triangulation supported with GPS precise point positioning (PPP) as a way to avoid the use of the GPS reference stations and simplify the work of aerial photography.Firstly, we present the algorithm for GPS PPP in aerial triangulation applications. Secondly, the error law of the coordinate of perspective centers determined using GPS PPP is analyzed. Thirdly, based on GPS PPP and aerial triangulation software self-developed by the authors, four sets of actual aerial images taken from surveying and mapping projects, different in both terrain and photographic scale, are given as experimental models. The four sets of actual data were taken over a flat region at a scale of 1:2500, a mountainous region at a scale of 1:3000, a high mountainous region at a scale of 1:32000 and an upland region at a scale of 1:60000 respectively. In these experiments, the GPS PPP results were compared with results obtained through DGPS positioning and traditional bundle block adjustment. In this way, the empirical positioning accuracy of GPS PPP in aerial triangulation can be estimated. Finally, the results of bundle block adjustment with airborne GPS controls from GPS PPP are analyzed in detail.The empirical results show that GPS PPP applied in aerial triangulation has a systematic error of half-meter level and a stochastic error within a few decimeters. However, if a suitable adjustment solution is adopted, the systematic error can be eliminated in GPS-supported bundle block adjustment. When four full GCPs are emplaced in the corners of the adjustment block, then the systematic error is compensated using a set of independent unknown parameters for each strip, the final result of the bundle block adjustment with airborne GPS controls from PPP is the same as that of bundle block adjustment with airborne GPS controls from DGPS. Although the accuracy of the former is a little lower than that of traditional bundle block adjustment with dense GCPs, it can still satisfy the accuracy requirement of photogrammetric point determination for topographic mapping at many scales.  相似文献   

20.
针对传统有理函数模型(RFM)区域网平差方法局限于姿态和轨道测量误差小、相机视场角小及影像交会角良好的情况,提出了附加视线向量修正的卫星影像区域网平差方法。首先利用影像附带的有理多项式系数(RPC)计算出像元视线向量,其次根据该视线向量恢复成像时刻虚拟位置和姿态信息,然后对恢复的虚拟位置和姿态构建误差补偿模型,最后通过最小二乘方法整体解算模型参数和连接点物方坐标。该方法从系统误差产生的原因构建补偿模型,可以规避传统区域网平差方法的近似假设和条件限制。通过对模拟数据以及多套测绘卫星和非测绘卫星数据进行试验的结果表明,该方法处理大姿态角误差、大视场角以及弱交会角等各种严苛条件下的卫星影像能达到比传统方法更好的效果。  相似文献   

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