Accuracy Analysis and Surface Mapping Using Spot 5 Stereo Data (original) (raw)
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Assessment of Dem Accuracy Derived from SPOT5 High Resolution Stereoscopic Imagery
This paper describes the derivation of Digital Surface Models (DSMs) from 3-fold along-track stereoscopic SPOT-5 imagery in the scope of the HRS (High Resolution Stereoscopic) study, organized by the Centre Nacional d'Études Spatiales (CNES) and the International Society of Photogrammetry and Remote Sensing (ISPRS). The orientation of SPOT-5 is reconstructed by bundle adjustment using a functional model based on correction polynomials. It resulted in an RMS-error of 2 m in Easting, Northing and Height at 17 check points. DSMs are produced for 4 test sites, which are located in different terrain types (mountainous, moderate and urban). An automatic region growing image matching process generates a dense point cloud in image space, which later is rigorously transformed into the object space and converted into a regular spaced DSM. The comparison with a digital terrain model (DTM) of superior accuracy yields standard deviations better than 5 m (1σ) in flat and moderate terrain and...
Evaluation of Mapping Accuracy of High-Resolution Stereoscopic Satellite Images
American Scientific Research Journal for Engineering, Technology, and Sciences, 2019
High resolution satellite images is still used in large scale mapping due to the need to produce fast products. High resolution stereoscopic satellite images present good enough 3d products that include the benefits of large-scale coverage and low-cost products. A stereopair of IKONOS satellite is used in this research that covers a part of North Sudan country. The study handles the 3d mapping accuracy of using stereoscopic satellite images. The study gives a spotlight on the accuracy in X, Y, Z and the space vector R. Another view of this study the N, E and elevation is indicated. The research environment is mainly ENVI software due to its capabilities of topographic processing module. Some distributed set of ground points (control and tie) was determined on the images and then observed using GPS surveying. Several experiments have been performed to evaluate the resulted mapping product.
Topographical Mapping from Stereo Satellite Data-Preliminary Findings
Proceeding of Asian …, 1992
The advent of high resolution Charged-Coupled-Device (CCD) and steerable capability of sensor on board the SPOT satellite provides necessary geometry for the restitution of 3-D vision requirements from its overlapping scenes acquired from the east and west orbit. Unlike the perspective geometry of conventional aerial photography, CCD sensor produces dynamic digital images which can be restituted digitally by auto-stereocorrelation technique. This paper reports the preliminary assessment of 3-dimensional mapping using SPOT-1 PLA data. Results of the test area covering 13km2 north and Kualal Lumpur revealed an accuracy with a standard deviation of 38.7m in planimetry and 18.6m in height. Refinement of ground control point framework and the algorithms adopted in this study is suggested to obtain the required accuracy for producing topographical maps. Due to the limitations in the system, it is suggested to restrict the area of work to consist only one particular terrain in order to achieve the goal.
SPOT Revisited: Accuracy Assessment, DEM Generation and Validation from Stereo Spot 5 HRG Images
SPOT 5 HRG Level 1A and 1B stereo scenes covering Zonguldak testfield in north-west Turkey have been analysed. They comprise the left and right image components with base to height ratio of 0.54. The pixel size on the ground is 5 m. The bundle orientation was executed by the PCI Geomatica V9.1.4 software package and resulted in 3D geopositioning to sub-pixel accuracies in each axis provided that at least six control points were used in the computation. Root mean square error (rmse) values and vectors of residual errors for Levels 1A and 1B are similar, even for different control and check point configurations. Based on the scene orientation, Level 1A and 1B digital elevation models (DEMs) of the testfield have been determined by automatic matching and validated by the reference DEM digitised from the 1:25 000 scale topographic maps, interferometric DEMs from Shuttle Radar Topography Mission (SRTM) X- and C-band SAR data and the GPS profiles measured along the main roads in the testfield. Although the accuracies of reference data-sets are too similar to the generated SPOT DEMs, these are the only high quality reference materials available in this area. Sub-pixel height accuracy was indicated by the comparison with profile points. However, they are in favourable locations where matching is always successful, so such a result may give a biased measure of the accuracy of the corresponding DEMs.
SPOT-5 HRS Along-Track Stereo Data Evaluation
2004
As part of CNES-ISPRS HRS Study Team investigation, SPOT-5 HRS along-track stereo data over Montmirail (France) and Melbourne (Australia) test sites were evaluated using the modified IRS-1C/1D stereo photogrammetric software Saphire and PCI Geomatica Orthoengine (version 9) software. Both the stereo pairs were processed using the four corners and one center pixel planimetric coordinates for each individual image as control points. The linearly interpolated satellite state vectors were used in the space resection module of the modified Saphire software to compute the updated attitude angles based on the control point coordinates, separately for each image. Conjugate points were automatically identified using interest points based hierarchical image matching. Using the space intersection module, (planimetric coordinates and) heights were computed at each conjugate point. These were interpolated to generate a uniform DEM grid of required spacing. For Montmirail, the DEM generated was c...
2010
The Working Group 4 of Commission I on “Geometric and Radiometric Modelling of Optical Spaceborne Sensors” will provide on its website several stereo data sets from high and very high resolution spaceborne stereo sensors. Among these are data from the 2.5 meter class like ALOS-PRISM and Cartosat-1 as well as, in near future, data from the highest resolution sensors (0.5 m class) like GeoEye-1 and Worldview-1. The region selected is an area in Catalonia, Spain, including city areas (Terrassa), rural areas and forests in flat and medium undulated terrain as well as steep mountainous terrain. In addition to these data sets, ground truth data like orthoimages from airborne campaigns and Digital Elevation Models (DEM) produced by laser scanning, all data generated by the Institut Cartografic de Catalunya (ICC), are provided as reference for comparison. The goal is to give interested scientists of the ISPRS community the opportunity to test their algorithms on DEM generation, to see how t...
GIScience & Remote Sensing, 2010
The launch of the Very High Resolution (VHR) sensor satellites has paved the way for further exploitation of the capabilities of satellite stereo imaging for many applications. The objective of this paper is to evaluate the level of accuracy that can be achieved by using stereo satellite images for different applications involving significantly different types of terrain. Three mathematical models for satellite sensor modeling are used: Rational Function Model (RFM), 3D polynomial model, and 3D affine model. Three stereo pairs of image datasets are tested from different satellites for different areas: (a) Indian Remote Sensing (IRS)-1D stereo images for topographic mapping and digital terrain elevation modeling for an area in Egypt; (b) IKONOS stereo images for highway alignments extraction in Toronto, Canada; and (c) IKONOS stereo images for topographic mapping and geometric parameter extraction for highway alignments in Hong Kong, China. The accuracy was evaluated by comparing the results of the data extracted using stereo satellite images and those extracted from conventional techniques, including Global Positioning System, field measurements, and aerial photogrammetry. The accuracy of the extracted features was found to be within a pixel-level. The results of this paper should be of interest to professionals from different disciplines exploring the use and accuracy of satellite stereo images for topographic and transportation applications.
Accuracy analysis, dem generation and validation using russian tk-350 stereo-images
The Photogrammetric Record, 2004
ABSTRACT TK-350 stereo-scenes of the Zonguldak testfield in the north-west of Turkey have been analysed. The imagery had a base-to-height ratio of 0·52 and covered an area of 200 km × 300 km, with each pixel representing 10 m on the ground. Control points digitised from 1:25 000 scale topographic maps were used in the test. A bundle orientation was executed using the University of Hanover program BLUH and PCI Geomatica OrthoEngine AE software packages. Tests revealed that TK-350 stereo-images can yield 3D geopositioning to an accuracy of about 10 m in planimetry and 17 m in height. A 40 m resolution digital elevation model (DEM) was generated by the PCI system and compared against a reference DEM, which was derived from digitised contour lines provided by 1:25 000 scale topographic maps. This comparison showed that accuracy depends mainly on the surface structure and the slope of the local terrain. Root mean square errors in height were found to be about 27 and 39 m outside and inside forested areas, respectively. The matched DEM demonstrated a systematic shift against the reference DEM visible as an asymmetric shift in the frequency distribution. This is perhaps caused by the presence of vegetation and buildings.RésuméOn a étudié des couples stéréoscopiques TK-350 sur le polygone d'essai ZONGULDAK au Nord-Ouest de la Turquie. Le rapport base-sur-altitude des couples était de 0,52 et la zone couverte atteignait 200 km × 300 km, avec une valeur au sol de chaque pixel de 10 m. On a saisi des points d'appui par numérisation à partir des cartes topographiques à l’échelle de 1:25 000. On a effectué l‘orientation des faisceaux en utilisant un ensemble de logiciels de l'Université de Hanovre tels que BLUH et « PCI Geomatica Ortho Engine AE ». Les essais ont montré que les stéréo-couples TK-350 pouvaient fournir une précision d'environ 10 m en planimétrie et 17 m en altimétrie sur le géopositionnement 3D. On a réalisé un MNA d'une résolution de 40 m avec le système PCI, que l'on a pu comparer avec un MNA de référence obtenu par numérisation des courbes de niveau des cartes topographiques au 1:25 000. La comparaison a montré que la précision dépendait essentiellement de la nature du terrain et de la pente locale. C'est ainsi que les erreurs moyennes quadratiques en altimétrie atteignent 39 m dans les zones boisées, contre 27 m en dehors. De plus, le MNA obtenu a présenté des systématismes par rapport au MNA de référence, sous la forme de décalages asymétriques dans la répartition des fréquences. La cause en est peut-être la présence de bâtiments et de végétation.ZusammenfassungIn diesem Beitrag wird über die Analyse von TK-350 Stereoszenen im Zonguldak Testfeld im Nordwesten der Türkei berichtet. Die Bilddaten hatten ein Basis-Höhenverhltnis von 0·52 und deckten ein Gebiet von 200 × 300 km mit einer Bodenpixelgröße von 10 m ab. Für den Test wurden Passpunkte aus einer Topographischen Karte im Maßstab 1:25 000 digitalisiert. Die Bündelausgleichung wurde mit dem Programmsystem BLUH der Universitt Hannover durchgeführt, weitere Analysen mit dem Paket PCI Geomatica OrthoEngine. Die Tests zeigten, dass mit TK-350 Stereoszenen eine 3D Geopositionierung mit einer Lagegenauigkeit von ca. 10 m und einer Höhengenauigkeit von 17 m möglich ist. Mit dem PCI System wurde ein DHM mit einer Gitterweite von 40 m erzeugt und mit einem Referenz-DHM, das aus digitalisierten Höhenlinien der Topographischen Karte 1:25 000 abgeleitet wurde, verglichen. Es zeigte sich, dass die Genauigkeit im wesentlich von der Gelndestruktur und der lokalen Gelndeneigung abhngt. Der mittlere quadratische Höhenfehler lag bei 27 m außerhalb von Waldgebieten und bei 39 m innerhalb von Waldgebieten. Das durch Bildzuordnung erzeugte DHM zeigte eine systematische Verschiebung gegenüber dem Referenzdatensatz, was an der asymmetrischen Verschiebung in der Hufigkeitsverteilung zu sehen ist. Diese wird vermutlich durch Vegetation und Gebude verursacht.ResumenEn este artículo se analizan imágenes estéreo TK-350 correspondientes a la zona de ensayo Zonguldak, en el noroeste de Turquía. Las imágenes tienen una razón base-altura de 0,52, cubren un área de 200 × 300 km, y tienen una resolución espacial de 10 m. Los puntos de control utilizados en el ensayo se han digitalizado a partir de mapas topográficos a escala 1:25 000 y se utilizaron los programas BLUH de la Universidad de Hannover y Geomatica OrthoEngine AE de PCI para la orientación. Las pruebas muestran que las imágenes estéreo TK-350 pueden alcanzar una exactitud de hasta 10 m en planimetría y de 17 m en altura en la georeferenciación 3D. Se generó un modelo digital de elevaciones (MDE) con una resolución de 40 m mediante el programa de PCI que se comparó con el MDE de referencia calculado a partir de las curvas de nivel digitalizadas de los mapas topográficos a escala 1:25 000. La comparación muestra que la exactitud depende principalmente de la estructura de la superficie y de la…
Accuracy and Completeness of Topographic Mapping from Spot Imagery
The Photogrammetric Record, 2006
A previous paper described the geometric model used to find the exterior orientation of dynamic SPOT imagery. The present paper considers the results of measurement and interpretation tests performed on a number of stereomodels. The image quality is assessed in comparison with the original digital data. Level 1A stereomodels with diflerent base:height ratios, numbers of control points and with different control point accuracies are compared. Accuracies obtained with level 1P and 1B data are also reported. The information content of the imagery is assessed by feature plotting followed by comparison with the 1:SO 000 and 1:lOO 000 scale maps of the area. The importance of high quality photographic imagery and operator experience are noted.
Sensors, 2012
The use of the small format digital action cameras has been increased in the past few years in various applications, due to their low budget cost, flexibility and reliability. We can mount these small cameras on several devices, like unmanned air vehicles (UAV) and create 3D models with photogrammetric technique. Either creating or receiving these kind of databases, one of the most important questions will always be that how accurate these systems are, what the accuracy that can be achieved is. We gathered the overlapping images, created point clouds, and then we generated 21 different digital surface models (DSM). The differences based on the number of images we used in each model, and on the flight height. We repeated the flights three times, to compare the same models with each other. Besides, we measured 129 reference points with RTK-GPS, to compare the height differences with the extracted cell values from each DSM. The results showed that higher flight height has lower errors, and the optimal air base distance is one fourth of the flying height in both cases. The lowest median was 0.08 meter, at the 180 meter flight, 50 meter air base distance model. Raising the number of images does not increase the overall accuracy. The connection between the amount of error and distance from the nearest GCP is not linear in every case.