Photogrammetria最新文献

Image optimization and classification procedures are comparatively analyzed and discussed relative to their possibilities and limitations for distinct applications. To meet the objectives LANDSAT Thematic Mapper data of two test-sites in different climatic areas (Saudi-Arabia and southwest Germany) have been chosen.

For optimized presentation of TM-imagery, a basic concept was developed through which structural as well as spectral image contents can be enhanced within one product. By choice of bands and processing parameters the concept can be modified and fitted to various applications. Supervised and unsupervised classification methods are applied, to separate surface phenomena by use of original, enhanced, and preprocessed data. Comparative evaluations have shown, that both methods give best results using not more than three spectral bands for one evaluation step. By qualitative and quantitative analysis it could be demonstrated, that classifying with original, enhanced or preprocessed components leads to the same results. For geologic applications in arid areas a standard band combination could be defined, which offers optimized conditions for rock discrimination and possibilities for separating diagnostic features. Concerning landuse applications, the various spectral behaviours of different surface phenomena cannot be meaningfully represented within one optimization product. The lack of structural (relief) information on classification results however could be compensated by special merging techniques under additional use of image optimization products.

Information retrieval requires a database and a host computer. Most scientific fields nowadays have their own database. However, in the field of photogrammetry and remote sensing we do not as yet have a comprehensive database. Information on the literature in our field is scattered over many databases, making retrieval cumbersome and expensive.

This paper analyzes the present state of affairs and summarizes details for establishing ISPRS-IRS, the Information Retrieval System of the International Society for Photogrammetry and Remote Sensing, which is tailored to cover surveying and mapping, including remote sensing. ISPRS-IRS should be available online and should be free-of-charge, using the postcard approach. In order to decide whether there is at present really a need to implement ISPRS-IRS, the next phase should be to collect data to judge the capabilities, efficiency, reliability and costs of the bibliographic and factual information which is available at present.

The scope of the discipline of artificial intelligence is reviewed and its relevance for the discipline of photogrammetry is analyzed. The most appropriate artificial-intelligence techniques are delt with more in detail, especially the usage of heuristics in algorithms, rule-based knowledge representation and programming, and also object-oriented programming. Urgent need for using expert-system technology is seen when replacing semiautomatic man-machine systems with fully automatic systems. In building expert systems, especially in gathering of knowledge as rules, a system-analytical approach is considered to be a necessity. It is concluded that the key issue will be the structuring task in the building of complex systems for photogrammetric analysis — also when gathering the knowledge-base for rule-based programming. In the future, it will be increasingly difficult to distinguish between the techniques and methods used in artificial intelligence and, on the other hand, those used in more conventional system design and software engineering.

Photogrammetry has passed through the phases of plane-table, analogue and analytical photogrammetry and we are now facing the next step, digital photogrammetry. In a transition period between phases, old concepts are transferred more or less unchanged to new technology. Examples of transition are given for concepts like DEM measurements in model space, epipolar geometry, adjustment by elements to estimate unknowns, error propagation, and datasnooping. These concepts are used in multi-point-matching and multi-image-matching in order to increase performance and reliability. Photogrammetrists and computer experts have to co-operate so as to develop and improve digital photogrammetry.

The Wadi El Allaqi area is the site of ancient and intermittent, recent activity in gold exploration and mining. The present work examines the application of remote sensing techniques to gold exploration under the natural conditions prevailing in this area. The geologic-lithologic units in the Wadi El Allaqi area have influenced the deposition of gold mineralizations. Rock units over 600 million years old act as hosts to the gold. Aerial photographs on a scale of 1:20,000 have been interpreted to delineate geologic-lithologic units, structural lineaments, and drainage and geomorphology. The results are compared with interpretations of Landsat imagery.