The thesis is concerned with an investigation of the possibilities of generating metric information and carrying out topographic mapping operations from side-looking radar images acquired from Earthorbiting satellites, as exemplified by the synthetic aperture radar (SAR) system flown onboard the Seasat satellite, Besides the theoretical analysis of the problem, several images covering test areas with different topographic characteristics have been used for extensive and comprehensive tests of the geometric accuracy of the SAR system; for experiments with digital monoplotting techniques applied to the SAR images; and for tests concerned with the detection and"interpretation of objects appearing on these images. The results show that metric information of a limited accuracy can be obtained from satellite SAR images. This could act as the basis for reconnaissance-type mapping at scales of 1: 250,000 and smaller. The geometric accuracy actually achieved does, however, depend heavily on the method used initially to process the SAR image data. In this respect, the results obtained with the digitally processed images are superior to those obtained with the optically processed images. The influence of the topographic relief present on the ground is also noticeable and various techniques have been devised and used to eliminate or substantially reduce this effect. The use of digital monoplotting techniques did not produce as good or as complete a rectification as expected due to the difficulties experienced with the interpretation of the terrain objects recorded on the SAR images. These result partly from the constraints in imaging direction that are an inherent feature of SAR imaging and which make the detection and interpretation of certain objects on an SAR image rather arbitrary. A further difficulty is the presence of background clutter on all the Seasat SAR images but which is especially noticeable on the optically processed images tested. At the present stage of the development and application of satellite SAR imagery for mapping, the limitations are centered around shortcomings in the image resolution and quality rather than the geometric characteristics of the imagery or the rectification techniques which have been devised and implemented for mapping purposes.
| Identifer | oai:union.ndltd.org:bl.uk/oai:ethos.bl.uk:237304 |
| Date | January 1982 |
| Creators | Ali, Abdalla Elsadig |
| Publisher | University of Glasgow |
| Source Sets | Ethos UK |
| Detected Language | English |
| Type | Electronic Thesis or Dissertation |
| Source | http://theses.gla.ac.uk/4060/ |
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