Precise geometric description of river sediment trails in the sea may assist in a better understanding of the complex processes happening in this type of environment. By means of stereo restitution of a Space Shuttle ...
Precise geometric description of river sediment trails in the sea may assist in a better understanding of the complex processes happening in this type of environment. By means of stereo restitution of a Space Shuttle Large Format Camera photo pair it could be shown that a three-dimensional survey of the margins of individual sediment trails is possible. It turns out, however, that the positioning of the measuring mark is not always easy, and that this type of plotting needs a well-experienced operator. The bathymetric information obtained is brought in relation to sedimentological aspects.
Three-dimensional restitution of images with unconventional imaging geometry can be performed in an operational mode using existing commercial analytical plotters without any extra investments in hardware. The paper p...
Three-dimensional restitution of images with unconventional imaging geometry can be performed in an operational mode using existing commercial analytical plotters without any extra investments in hardware. The paper presents two programme systems developed for the Kern DSR analytical stereo-plotter for mapping with spaceborne stereo-imagery, one for images acquired by the SPOT HRV sensor, the other one for stereo-mensuration of SAR images. Due to the movement of the satellite platforms the software requires appropriate algorithms for the consideration of time-varying orientation parameters like sensor position, sensor attitude or others. The performance of the programme systems is demonstrated with practical results derived from Space Shuttle SIR-B imagery as well as from SPOT images showing realistically achievable accuracies of a few pixels in planimetry.
作者：
Kainz, WolfgangResearch Cent Joanneum
Inst for Image Processing & Computer Graphics Graz Austria Research Cent Joanneum Inst for Image Processing & Computer Graphics Graz Austria
This paper presents data structures and procedures for attribute assignment in geographical information system. Despite suggestions to apply conventional data base management systems for the manipulation of both spati...
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This paper presents data structures and procedures for attribute assignment in geographical information system. Despite suggestions to apply conventional data base management systems for the manipulation of both spatial and attribute data we take a different approach. Spatial data is stored in a way which takes into account the special nature of spatial information. Thematic information is represented hierarchically. For each subject a global theme file describes the hierarchy, data fields and types of each attribute item for each level. A copy of this structure gives the local theme file. Attributes may be assigned to spatial items, and vice versa, by an interactive process during or after digitization. Relations between corresponding items are established via a link file with pointers in either direction thus providing even multiple assignments.
Spring and summer acquired Thematic Mapper data of a spruce forest growing in southeastern Austria show the normalised differences ND1 and ND3, ratio R41, band differences BD1 and BD3, and the greenness index TMG empl...
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In this paper we consider the limitations of Linear Discriminative Analysis (LDA) when applying it for large-scale problems. Since LDA was originally developed for two-class problems the obtained transformation is sub...
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ISBN:
(纸本)9789898111692
In this paper we consider the limitations of Linear Discriminative Analysis (LDA) when applying it for large-scale problems. Since LDA was originally developed for two-class problems the obtained transformation is sub-optimal if multiple classes are considered. In fact, the separability between the classes is reduced, which decreases the classification power. To overcome this problem several approaches including weighting strategies and mixture models were proposed. But these approaches are complex and computational expensive. Moreover, they were only tested for a small number of classes. In contrast, our approach allows to handle a huge number of classes showing excellent classification performance at low computational costs. The main idea is to split the original data into multiple sub-sets and to compute a single LDA space for each sub-set. Thus, the separability in the obtained subspaces is increased and the overall classification power is improved. Moreover, since smaller matrices have to be handled the computational complexity is reduced for both, training and classification. These benefits are demonstrated on different publicly available datasets. In particular, we consider the task of object recognition, where we can handle up to 1000 classes.
Possibilities and techniques for the combined use of SAR and high resolution optical satellite imagery are discussed. Differences in imaging geometry and scene illumination complicate the analysis of multi-sensor data...
Spaceborne stereo-imagery can serve two major purposes: relief mapping and extraction of thematic information. Not only camera-acquired photogrammetric data of conventional and super-large format, but also hand-held p...
The analysis of images can take advantage of existing knowledge;this may be denoted as data-driven or knowledge-based image analysis. One example is the use of topographic maps in the study of aerial imagery. We repor...
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Grain size of forged nickel alloy is an important feature for the mechanical properties of the material. For fully automatic grain size evaluation in images of micrographs it is necessary to detect the boundaries of e...
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