Ultramap: The All in One Photogrammetric Solution (original) (raw)
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DSM and True Ortho Generation with the Ultracam-L -- a Case Study
2010
Dense Matching is used to match a huge number of pixels automatically to generate a surface model from a set of overlapping digital images. Once a DSM has been processed, it then can be used to generate a so called true-ortho image. Such a true-ortho image has significant advantages over a standard ortho image. Typically, two sensors are used to generate such a true-ortho image: a Lidar sensor system to generate the DSM and an aerial camera to generate the aerial image. Currently another approach is under development which is based on aerial images only. The DSM will be generated by a dense match of the aerial images. The advantage is obvious: only one sensor is required and the expected quality of the true-ortho images is higher due to the higher resolution of the underlying DSM. This case study shows the results of such a dense matching, DSM and true-ortho image generation process based on survey flights undertaken with the new UltraCamL. The UltraCamL is the so called "large...
Ultramap V3 – a Revolution in Aerial Photogrammetry
ISPRS - International Archives of the Photogrammetry, Remote Sensing and Spatial Information Sciences, 2012
In the last years, Microsoft has driven innovation in the aerial photogrammetry community. Besides the market leading camera technology, UltraMap has grown to an outstanding photogrammetric workflow system which enables users to effectively work with large digital aerial image blocks in a highly automated way. Best example is the project-based color balancing approach which automatically balances images to a homogeneous block. UltraMap V3 continues innovation, and offers a revolution in terms of ortho processing. A fully automated dense matching module strives for high precision digital surface models (DSMs) which are calculated either on CPUs or on GPUs using a distributed processing framework. By applying constrained filtering algorithms, a digital terrain model can be derived which in turn can be used for fully automated traditional ortho texturing. By having the knowledge about the underlying geometry, seamlines can be generated automatically by applying cost functions in order to minimize visual disturbing artifacts. By exploiting the generated DSM information, a DSMOrtho is created using the balanced input images. Again, seamlines are detected automatically resulting in an automatically balanced ortho mosaic. Interactive block-based radiometric adjustments lead to a high quality ortho product based on UltraCam imagery. UltraMap v3 is the first fully integrated and interactive solution for supporting UltraCam images at best in order to deliver DSM and ortho imagery.
Digital True Orthophotos Generation
2005
Orthophoto is a photographic document on which effects of terrain height and camera attitudes are removed. It constitutes hence a document on which precise measurement can be done similar to the map. With the advances in digital techniques, digital orthophotos are becoming very popular within the GIS community. However, as orthophotos do not generally take into account the surface model in the rectification, superimposition of vector data on orthos in urban or sub urban areas is unsatisfactory, mainly when height differences are important. The generation of digital true orthophotos using a digital surface model is the only way to correct these effects.
TS 27 – Remote Sensing Digital True Orthophotos Generation
Orthophoto is a photographic document on which effects of terrain height and camera attitudes are removed. It constitutes hence a document on which precise measurement can be done similar to the map. With the advances in digital techniques, digital orthophotos are becoming very popular within the GIS community. However, as orthophotos do not generally take into account the surface model in the rectification, superimposition of vector data on orthos in urban or sub urban areas is unsatisfactory, mainly when height differences are important. The generation of digital true orthophotos using a digital surface model is the only way to correct these effects.
The Generation of True Orthophotos Using a 3D Building Model in Conjunction with a Conventional DTM
1998
For the time being usual orthophotos do not place general 3D objects (buildings, bridges, etc) on their geometrically correct positions because conventional algorithms are based on 2.5D digital terrain models (DTM) thus limiting significantly the possibility of describing the real 3D shape of the objects and inhibiting the correct calculation of visibility. For large and medium scale image maps quite often the effect of wrong mapping cannot be tolerated any more and the generation of so-called true orthophotos becomes obligatory. In addition to the DTM 3D digital building models (DBM) must be introduced. Here three approaches are presented dependent on the complexity of the object surface. The methods differ in the way to treat the DTM and DBM in the rectification process and in the visibility analysis. Open areas with simple buildings do not need visibility analysis at all, while in urban areas with complex buildings visibility analysis within the DBM becomes compulsory. The most general approach performs a visibility analysis within the DSM (digital surface model) which is a common data base of DBM and DTM. A true orthophoto program has been developed, that can create all three types of orthophotos from aerial as well as close-range photographs.
… of SilviLaser 2008, 8th …, 2008
The combined analysis of lidar and image datasets for information extraction of forest structural attributes and composition requires that the image-to-lidar geometric correspondence be known accurately. We propose a series of methods for producing a 10 cm high quality true orthomosaic of Vexcel UltraCam images perfectly adjusted to the lidar digital surface model (DSM). First, we introduce a technique for filling the small cavities visible on lidar raster DSMs. We then assess the image-to-lidar registration using visualization and quantitative approaches. The small geometric discrepancy measured between the two datasets is then corrected. In the image overlap areas, the true orthomosaic is created by choosing the contributing image that has the smallest distance to the corresponding DSM pixel. Occluded pixels that can not be seen from any centre of perspective are then filled with synthetic values calculated according to their sunlit/shadowed state at the time the images were taken. The resulting true orthomosaic is perfectly registered to the lidar dataset, is complete (considering occluded pixels receive synthetic values), is not radiometrically altered, and shows no visible cut lines. The proposed process should greatly help the simultaneous analysis of lidar and image datasets.
A Simpler Method for Large Scale Digital Orthophoto Production
… of the Photogrammetry, Remote sensing and …, 2008
Digital orthophotography has been a powerful tool for large scale geometric documentation of monuments for over a decade. However, several factors prevent the smooth implementation of commercially available software for the production of digital orthophotos. The production of orthophotographs presents even more special problems, as it usually is a case of a highly demanding true orthophoto. Special techniques have been proposed in the past to address these problems in the best possible way. However no clearly defined solution to the above has been implemented. Terrestrial laser scanning techniques have helped the situation a lot, as they are able to provide a more detailed description of the object's surface, a fact which contributes to a more successful implementation of traditional orthophoto production algorithms. However, even this solution is by no means complete, as it imposes limitations to the orientation of the stereopairs, the position of the projective planes for the final orthophoto and, of course, to the completeness of the final product. Several attempts have been reported in the past in order to help overcome these limitations. In this paper a novel and simple method developed for the production of orthophotography at large scales is described and assessed. This method successfully attempts to produce orthophotos at large scales using a point cloud and freely taken pictures of the object, thus achieving two goals. Firstly the user may work independently from the practical constraints imposed by the commercially available software and secondly there is no need for specialized knowledge for implementing complicated photogrammetric techniques, or specialized photogrammetric or pre-calibrated cameras, since self-calibration may take place, thus making the method attractive to non-photogrammetrists.
New Methodologies for True Orthophoto Generation
Photogrammetric Engineering & Remote Sensing, 2007
Orthophoto production aims at the elimination of sensor tilt and terrain relief effects from captured perspective imagery. Uniform scale and the absence of relief displacement in orthophotos make them an important component of GIS databases, where the user can directly determine geographic locations, measure distances, compute areas, and derive other useful information about the area in question. Differential rectification has been traditionally used for orthophoto generation. For large scale imagery over urban areas, differential rectification produces serious artifacts in the form of double mapped areas at object space locations with sudden relief variations, e.g., in the vicinity of buildings. Such artifacts are removed through true orthophoto generation methodologies which are based on the identification of occluded portions of the object space in the involved imagery. Existing methodologies suffer from several problems such as their sensitivity to the sampling interval of the digital surface model (DSM) as it relates to the ground sampling distance (GSD) of the imaging sensor. Moreover, current methodologies rely on the availability of a digital building model (DBM), which requires an additional and expensive pre-processing. This paper presents new methodologies for true orthophoto generation while circumventing the problems associated with existing techniques. The feasibility and performance of the suggested techniques are verified through experimental results with simulated and real data.
Proceedings of the 16th ACM SIGSPATIAL international conference on Advances in geographic information systems - GIS '08, 2008
Commercial aerial imagery websites, such as Google Maps, MapQuest, Microsoft Virtual Earth, and Yahoo! Maps, provide high-seamless orthographic imagery for many populated areas, employing sophisticated equipment and proprietary image postprocessing pipelines. There are many areas of the world with poor coverage where locals might benefit from recent, high-resolution orthographic imagery, but which do not fit into the schedules and scaling model of the big sites.