Photogrammetric point determination and DEM generation using MOMS-2P/PRIRODA three-line imagery (original) (raw)
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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…
Sensor Integration And Calibration Of Digital Airborne Three-Line Camera Systems
The determination of the exterior orientation parameters is an essential pre-requisite for the evaluation of any imagery from terrestrial, airborne or satellite based sensors. Normally, this georeferencing processing is solved indirectly by using a number of well known ground control points and their corresponding image coordinates. Using a mathematical model for the relation between image and object space the exterior orientations can be calculated and the local image coordinates are related to the global ground coordinate system. In principle this approach can be applied for georeferencing of push-broom line scanner imagery, but this process is highly inefficient. Due to the large number of unknowns a large number of tie and control points is necessary for orientation determination. To allow an operational processing the direct measurement of exterior orientation using GPS and INS and additional information is inevitable. Within this article the geometric processing of high resolu...
Local, Regional and Global Point Determination Using Three-Line Imagery and Orbital Constraints
2007
The emphasis of that paper is point determination using spaceborne 3-line imagery and orbital constraints. In order to properly utilize the image information contained in conjugate point coordinates and the orbit information contained in tracking data, both data types have to be evaluated in a combined adjustment process. To this end, the conventional bundle block adjustment algorithm is supplemented by a rigorous dynamical modeling of the satellite motion to take orbital constraints into account. For the forthcoming Mars96 HRSC/WAOSS experiment computer simulations on point determination have been performed to obtain a survey of the attainable accuracy at local, regional and global levels. Since WAOSS will image the entire planet, a closed block covering the entire Martian surface may be processed under ideal circumstances. Because of the extraordinary strength of the closed block and based on the complete image, orbit, attitude and ground control information, 60 m accuracy in X, Y...
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The current state of the art in checking the planimetric accuracy of Digital Elevation Models derived from Airborne Laser Scanning is analyzed. The principle of a proposed method is presented including the mathematical equations. Special emphasis is given to the precision of derived points which are used for the comparison with true values. Least squares adjustment is applied and the influence of blunders in the observations is reduced by means of the iterative determination of weights as a function of the size of the corrections. Practical tests have been carried out with data from the new Digital Elevation Model of Denmark. The required reference values were derived by means of aerial images and photogrammetric techniques. A few ground control points were determined by GPS. The reliability and practicability of the method is then discussed on the basis of the experiences obtained from the practical usage of the method. It is concluded that the proposed method is accurate, robust a...
Accuracy Analysis of Dems Derived from Aster Imagery
ASTER acquires along track stereoscopic imagery, with a spatial resolution of 15 meters. Automatic generation of Digital Elevation Models (DEMs) from these images is a well established process, implemented in many commercial software packages. It can provide relief information for areas with poor coverage of topographic mapping. This paper presents a study of the accuracy achieved in DEMs extracted from ASTER, for an area in Portugal, using the PCI OrthoEngine software. Images were orientated with ground control points (GCP) obtained from topographic maps. Experiments were carried out in reducing the number of GCPs. A number of 5 or 6 GCPs was always required to orient the images, in order to keep the accuracy achieved with larger numbers of points. It was possible to conclude that more use could have been done of the approximate orientation provided in the image header. A grid of points derived from the sensor position and attitude, estimated by onboard equipment, is given in the i...
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.
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...
Calibration of Industrial Cameras for Aerial Photogrammetric Mapping
Remote Sensing, 2020
This paper details the development of a camera calibration method purpose-built for use in photogrammetric survey production. The calibration test field was established in a hangar, where marker coordinates were measured using a high-precision survey methodology guaranteeing very high accuracy. An analytical model for bundle adjustment was developed that does not directly use the coordinates of field calibration markers but integrates bundle adjustment and survey observations into a single process. This solution, as well as a classical calibration method, were implemented in a custom software, for which the C++ source code repository is provided. The method was tested using three industrial cameras. The comparison was drawn towards a baseline method, OpenCV implementation. The results point to the advantages of using the proposed approach utilizing extended bundle adjustment.
This paper describes the methodology of a DEM generation from stereo aerial images and the results of experiments in terms of accuracy of generated DEM. In this study, Images, which have 1/10000 and 1/16000 scale, and a test area established about 1 km 2 in Selcuk University Campus Area were used. Aerial photographs were scanned by ZEISS SCAI Photogrammetric Scanner (pixel size is 21µ). Aerial images, which have 1/10000 scale, were restitutied by Zeiss Planicomp P3 Analytical Instrument. The DEM, which belong to test area, were produced by progressive, selective and composite sampling methods. We have developed a new software on PC's that can automatically generate DEM from stereo aerial images for restitution of images 1/16000 scale. In this software, pixel and image coordinates of points in left and right image are calculated by using colinearity equations. Left and right windows are matched and this process is repeated in various ±∆Z range. Elevation values obtained from the best-fixed matching are automatically selected as optimum elevation value. Elevation values of points in the test area are calculated by bilinear interpolation method which uses coordinates of above points (X,Y,Z). Moreover, Elevations of points in test area are manually produced from PHOTOMOD software. RMS obtained from both analytical and digital methods are compared with similar study in the relevant literature.
In unmanned aerial vehicle (UAV) photogrammetric surveys, the camera can be pre-calibrated or can be calibrated "on-the-job" using structure-from-motion and a self-calibrating bundle adjustment. This study investigates the impact on mapping accuracy of UAV photogrammetric survey blocks, the bundle adjustment and the 3D reconstruction process under a range of typical operating scenarios for centimetre-scale natural landform mapping (in this case, a coastal cliff). We demonstrate the sensitivity of the process to calibration procedures and the need for careful accuracy assessment. For this investigation, vertical (nadir or near-nadir) and oblique photography were collected with 80%-90% overlap and with accurately-surveyed (σ ≤ 2 mm) and densely-distributed ground control. This allowed various scenarios to be tested and the impact on mapping accuracy to be assessed. This paper presents the results of that investigation and provides guidelines that will assist with operational decisions regarding camera calibration and ground control for UAV photogrammetry. The results indicate that the use of either a robust pre-calibration or a robust self-calibration results in accurate model creation from vertical-only photography, and additional oblique photography may improve the results. The results indicate that if a dense array of high accuracy ground control points are deployed and the UAV photography includes both vertical and oblique images, then either a pre-calibration or an on-the-job self-calibration will yield reliable models (pre-calibration RMSE XY = 7.1 mm and on-the-job self-calibration RMSE XY = 3.2 mm). When oblique photography was excluded from the on-the-job self-calibration solution, the accuracy of the model deteriorated (by 3.3 mm horizontally and 4.7 mm vertically). When the accuracy of the ground control was then degraded to replicate typical operational practice (σ = 22 mm), the accuracy of the model further deteriorated (e.g., on-the-job self-calibration RMSE XY went from 3.2-7.0 mm). Additionally, when the density of the ground control was reduced, the model accuracy also further deteriorated (e.g., on-the-job self-calibration RMSE XY went from 7.0-7.3 mm). However, our results do indicate that loss of accuracy due to sparse ground control can be mitigated by including oblique imagery.