共查询到20条相似文献，搜索用时 671 毫秒
1.
线阵推扫式影像外定向的一种新算法 总被引：4，自引：2，他引：2
线阵推扫式影像外方位元素间的强相关性,导致法方程病态,外方位元素的最小二乘估计值误差较大.本文提出采用岭-压缩组合估计解决线阵列推扫式影像的外定向问题.该算法是综合岭估计和压缩估计的一种新有偏算法,它通过对最小二乘估计值的不同分量进行不同比例的压缩使估计值最优.文中采用10 m分辨率的SPOT 1全色影像和2.5 m分辨率的SPOT 5全色影像进行实验,并与商业遥感软件Erdas的实验结果进行比较.研究结果表明该算法能有效地克服线阵推扫式影像外方位元素间的相关性,定位精度较高,定向点精度在1个像素内,检查点精度在1.5个像素内,达到Erdas软件的定位精度. 相似文献
2.
Large area tree maps, important for environmental monitoring and natural resource management, are often based on medium resolution satellite imagery. These data have difficulty in detecting trees in fragmented woodlands, and have significant omission errors in modified agricultural areas. High resolution imagery can better detect these trees, however, as most high resolution imagery is not normalised it is difficult to automate a tree classification method over large areas. The method developed here used an existing medium resolution map derived from either Landsat or SPOT5 satellite imagery to guide the classification of the high resolution imagery. It selected a spatially-variable threshold on the green band, calculated based on the spatially-variable percentage of trees in the existing map of tree cover. The green band proved more consistent at classifying trees across different images than several common band combinations. The method was tested on 0.5 m resolution imagery from airborne digital sensor (ADS) imagery across New South Wales (NSW), Australia using both Landsat and SPOT5 derived tree maps to guide the threshold selection. Accuracy was assessed across 6 large image mosaics revealing a more accurate result when the more accurate tree map from SPOT5 imagery was used. The resulting maps achieved an overall accuracy with 95% confidence intervals of 93% (90–95%), while the overall accuracy of the previous SPOT5 tree map was 87% (86–89%). The method reduced omission errors by mapping more scattered trees, although it did increase commission errors caused by dark pixels from water, building shadows, topographic shadows, and some soils and crops. The method allows trees to be automatically mapped at 5 m resolution from high resolution imagery, provided a medium resolution tree map already exists. 相似文献
3.
4.
The relative abundance and distribution of trees in savannas has important implications for ecosystem function. High spatial resolution satellite sensors, including QuickBird and IKONOS, have been successfully used to map tree cover patterns in savannas. SPOT 5, with a 2.5 m panchromatic band and 10 m multispectral bands, represents a relatively coarse resolution sensor within this context, but has the advantage of being relatively inexpensive and more widely available. This study evaluates the performance of NDVI threshold and object based image analysis techniques for mapping tree canopies from QuickBird and SPOT 5 imagery in two savanna systems in southern Africa. High thematic mapping accuracies were obtained with the QuickBird imagery, independent of mapping technique. Geometric properties of the mapping indicated that the NDVI threshold produced smaller patch sizes, but that overall patch size distributions were similar. Tree canopy mapping using SPOT 5 imagery and an NDVI threshold approach performed poorly, however acceptable thematic accuracies were obtained from the object based image analysis. Although patch sizes were generally larger than those mapped from the QuickBird image data, patch size distributions mapped with object based image analysis of SPOT 5 have a similar form to the QuickBird mapping. This indicates that SPOT 5 imagery is suitable for regional studies of tree canopy cover patterns. 相似文献
5.
T. Westin 《The Photogrammetric Record》1991,13(78):923-929
A mathematical model for pass processing of SPOT imagery is formulated. It is based on the fact that during one pass, the image data stream from each of the instruments in SPOT forms one single very long image. The geometry of this extended image can thus be rectified with as few control points as for only one scene if orbital constraints and attitude measurements are properly taken into consideration. SPOT imagery is, however, not available as this single long image, but only sectioned into scenes. This creates problems which are accounted for in the solution. The possibility of gaps in the sequence of scenes is also taken into consideration. Extrapolation over gaps is of special interest and, by investigating attitude variability, it is shown that extrapolation is successful over multiple scene gaps which is also verified in a real data test. 相似文献
6.
基于物方空间几何约束最小二乘匹配的建筑物半自动提取方法 总被引：8，自引：0，他引：8
提出了一种从数字航空立体像对半自动提取建筑物的方法。操作员通过人机界面选择房屋的种类并输入初始位置，然后经过边缘检测、直线段提取和据此房屋几何模型的线段自动编组等处理得到各房屋角点的初始位置，最后，为了获得房屋的精确定位和符合物方严格几何约束的结果，基于物方空间几何约束的最小二乘匹配平差模型用于求取房屋直线边缘和物方几何模型的最优匹配，试验表明，该方法能提高建筑物的提取精度并可为半自动建筑物提取提供一个灵活的框架。 相似文献
7.
C.Y. Ji 《ISPRS Journal of Photogrammetry and Remote Sensing》1996,51(6):268-283
Agricultural field boundary information is important in the study of agricultural crops by remote sensing. In this paper, the dyadic wavelet transform is adopted to extract field boundaries directly from TM imagery. A field boundary is a set of locally connected pixels characterized by their abrupt spectral intensity variation (singularity) on the image. Preliminary extraction is made on the near-infrared Band 4 (0.76–0.90 μm) image. It is found that most of the boundaries are well characterized by the wavelet modulus maxima curves, particularly for fully vegetated fields, while better results are obtained from the NDVI image for cropped field boundaries. To extract additional boundaries while suppressing unwanted noisy edges, the wavelet transform is then applied to the Wetness image calculated by the Tasselled Cap Transform. A technique is implemented to integrate the edges extracted from each source. The combined results show that the majority of the field boundaries are delineated. The use of a single date image fails to delineate some of the fallow field boundaries and boundaries between two cropped fields with similar spectral properties. Although techniques have been applied to reduce noise, still great difficulties are encountered when trying to delineate edges that are field boundaries from all the detected singularities. Manual editing is still required to trace the remaining boundaries to obtain a complete boundary map. It is recommended that a multi-temporal data set be used to obtain a complete delineation with a fully automated algorithm. 相似文献
8.
The paper presents a general paradigm of semiautomatic building extraction from aerial stereo image pair. In the semiautomatic extraction system, the building model is defined by selected roof type through human-machine interface and input the approximation of area where the extracted building exists. Then under the knowledge of the roof type, low-level and mid-level processing including edge detection, straight line segments extraction and line segments grouping are used to establish the initial geometrical model of the roof-top. However, the initial geometrical model is not so accurate in geometry. To attain accurate results, a general least squares adjustment integrating the linear templates matching model with geometrical constraints in object-space is applied to refine the initial geometrical model. The adjustment model integrating the straight edge pattern and 3D constraints together is a well-studied optimal and anti-noise method. After gaining proper initial values, this adjustment model can flexibly process extraction of kinds of roof types by changing or assembling the geometrical constraints in object-space. 相似文献
9.
ZHANG ZuxunHU XiangyunZHANG Jianqing 《地球空间信息科学学报》2001,4(4):49-55
1 ＩｎｔｒｏｄｕｃｔｉｏｎＡｔｐｒｅｓｅｎｔ,ｍａｎｙｃｏｍｍｅｒｃｉａｌｄｉｇｉｔａｌｐｈｏｔｏｇｒａｍ ｍｅｔｒｉｃｗｏｒｋｓｔａｔｉｏｎｓ (ＤＰＷ )ｈａｖｅｂｅｅｎｄｅｖｅｌｏｐｅｄａｎｄａｐｐｌｉｅｄｉｎｔｏｐｒａｃｔｉｃａｌｐｒｏｄｕｃｔｉｏｎ .Ｍｏｓｔｏｆｔｈｅｍｃａｎａｕｔｏｍａｔｉｃａｌｌｙ ｇｅｎｅｒａｔｅｄｉｇｉｔａｌｔｅｒｒａｉｎｍｏｄｅｌ(ＤＴＭ)ａｎｄｄｉｇｉｔａｌｏｒｔｈｏ＿ｉｍａｇｅ (ＤＯＭ ) ,ｂｕｔｔｈｅｒｅａｒｅｎｏｔａｎｙｓｙｓｔｅｍｓｗｈｉｃｈｃａｎａｕｔｏｍａ… 相似文献
10.
岭-压缩组合估计在线阵推扫式影像外定向中的应用 总被引：4，自引：0，他引：4
针对线阵推扫式影像外定向中存在的法方程病态问题,提出了采用岭压缩组合估计进行解算,能提高定向精度,并分析了该算法的优点和应用方法。实验证明,该算法性能优异,精度很高。 相似文献
11.
稀少控制条件下的SPOT 5 HRS影像定向试验 总被引：1，自引：0，他引：1
通过生产试验,探讨了不同控制点数量及分布下的SPOT 5 HRS影像的定向精度问题,分析了稀少控制点定向后SPOT 5 HRS影像的误差分布情况,为SPOT 5 HRS影像在外业控制点获取困难地区的应用提供了可行方法。 相似文献
12.
Nathalie Pisot Jean-Paul Xavier Vronique Miegebielle Dominique Coquelet Pierre Leymarie 《ISPRS Journal of Photogrammetry and Remote Sensing》1993,48(6)
This paper illustrates the benefits of DTMs created from SPOT images for the exploration of sedimentary basins. We chose an example located in the Ebro sedimentary basin in Spain, characterized by good outcropping conditions and slight deformations. The data used consist of a pair of SPOT panchromatic images and a SPOT XS image. The work consists of making up a 3D database, followed by interpretation of stereo pairs computed from orthoimages and the DTM. This interpretation is made on a stereoscopic desk and results in a digital file containing in the form of vectors all the observed faults and lithology. These vectors are then used to make calculations on the geometry of the objects they represent: we demonstrate that we can accurately measure layer directions and dips, sediment thicknesses and fault throws. Synthesis of perspective views made at the same time provide a good understanding of the structures and help to test their geometric consistency. Thus knowledge about relief given by DTMs helps to interpret remote detection images in 3D space, and particularly to accurately quantify the results of this interpretation. 相似文献
13.
以"像方观测直线与像方预测直线必须重合"作为几何约束条件,以有理函数模型(RFM)作为高分辨率卫星影像的几何处理模型,提出了一种直线特征约束的高分辨率卫星影像区域网平差方法。本文方法仅需像方直线与物方直线相对应,无须像方直线上的像点与物方直线上的地面点一一对应。通过对圣迭戈试验区的两景IKONOS影像、斯波坎试验区的两景QuickBird影像和普罗旺斯试验区的两景SPOT-5影像进行试验,结果表明:本文方法可以充分利用直线特征作为控制条件,有效补偿RPC参数中的系统误差,获得的IKONOS、QuickBird和SPOT-5影像区域网平差的平面与高程精度均优于1个像素。 相似文献
14.
15.
利用MIVIS数据进行遥感图像模拟的研究 总被引：12，自引：0，他引：12
本文研究利用机载ＭＩＶＩＳ超光谱成像系统数据,运用光谱模拟,大气改正的方法,定量模拟了ＳＰＯＴ－ＨＲＶ ＸＳ１、ＸＳ２、ＸＳ３的地面反射率图像,并将模拟结果与相应的地面反射率实测值进行了对比。同时对成像系统ＭＴＦ的影响也进行了定量模拟分析。试验结果显示,ＳＰＯＴ图像的模拟值与地面实测值相一致。 相似文献
16.
本文从理论上分析了以全数字化方法从SPOT影象提取高程信息关键环节上的问题和所采取的方法。根据影象成象特点,采用时序变化的外方位元素数学模型,其中精确选取控制点、合理选取初值和确定等效焦距、线元素和角元素分开解算迭代是十分重要的措施。采用新的数据组织方法可以避免高程内插中的精度损失。利用卫星影象特点,实现由粗到精的多级影象匹配,同时引人改化的高精度最小二乘匹配,使整个匹配过程既保障了可靠性又满足精度要求。马赛地区SPOT象对窗的DEM生成结果表明,在影象质量得到保证,时差不大的前提下,可以达到10米高程精度。 相似文献
17.
Abstract Landsat MSS, TM and SPOT XS imageries were used in conjunction with unsupervised, supervised and hybrid classilication techniques to classify land cover types in semi‐arid savannas of Mathison Pastoral Station in the Katherine region of northern Australia. Accuracy assessment was based on field data from 246 ground survey sites over a 745‐km2 study area. Of 14 land cover classes identified by traditional mapping means, all combinations of imageries and classification techniques differentiated at least seven land cover types. The overall accuracy for these classifications ranged between 43% and 67%. SPOT XS image delivered the best accuracy followed by TM and MSS; unsupervised classification performed better than supervised and hybrid methods. User's and producer's accuracy of individual land units ranged from 0% to 100%. Riparian woodlands, woodland on limestone slopes, shrubland on clay plains, woodland on limestone plains and shadows were the best‐mapped classes. The land units that were associated with undulating hills were not mapped accurately. However, incorporation of a digital elevation model (DEM) in a GIS improved the overall accuracy. The user's and producer's accuracy of dominant land cover types were also enhanced. The classification results and the efficacy of the techniques at Mathison were similar to those found for a nearby semi‐arid area (Kidman Springs) about 200 km from Mathison. However, the overall accuracy was lower at Mathison than at Kidman Springs. Spectral classification masks were developed from the SPOT XS and TM imageries at Kidman Springs, and were applied to classify SPOT XS and TM imageries at Mathison. Initial results showed that the classification mask could be successfully extrapolated to map dominant land cover types but only with moderate accuracy (50%). 相似文献
18.
19.
SPOT立体影象具有良好的基高比和空间分辨率,可以利用解析摄影测量仪器对之进行精确而有效的处理,以求解外方位元素,测制或修测地形图,获取数字高程模型以及制作正射影象。本文分析了SPOT影象的几何特性,建立了SPOT立体象对求解的数学模型。利用作者研制的SPOT影象光束法平差程序、C-100解析测图仪上SPOT象对测图软件和在OR-1正射投影仪上制作SPOT正射影象的相应软件,对法国马赛地区的一对SPOT立体象对进行了试验,获得了满意的结果。 相似文献
20.
陈鹰 《武汉大学学报(信息科学版)》1988,(4)
本文从王之卓教授关于“数字图象处理将是摄影测量的一个新的作业领域”的观点出发,介绍了用数字图象处理的方法解决摄影测量问题方面的某些进展,主要是:快速数字微分纠正,影象增强与镶嵌,数字立体正射影象图,LANDSAT和SPOT卫星图象的参量估计与星历数据的利用。 相似文献