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Effects of the intervals of tie points used in co‐registration on the accuracy of digital elevation models generated by INSAR
Author(s) -
Zou Weibao,
Li Zhilin,
Ding Xiaoli
Publication year - 2006
Publication title -
the photogrammetric record
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.638
H-Index - 51
eISSN - 1477-9730
pISSN - 0031-868X
DOI - 10.1111/j.1477-9730.2006.00382.x
Subject(s) - interferometric synthetic aperture radar , pixel , synthetic aperture radar , digital elevation model , remote sensing , elevation (ballistics) , point (geometry) , interval (graph theory) , artificial intelligence , computer science , geodesy , computer vision , geology , mathematics , geometry , combinatorics
Abstract Interferometric Synthetic Aperture Radar (InSAR) is a new measurement technology, making use of the phase information contained in Synthetic Aperture Radar (SAR) images. InSAR has been recognised as a potential tool for the generation of digital elevation models (DEMs) and the measurement of ground surface deformation. In InSAR data processing for the generation of DEMs, the first step is image co‐registration, which brings both images into the same coordinate system for the generation of an interferogram for further processing. The accuracy of the resultant DEM will certainly be affected by the quality of the co‐registration, which is in turn affected by the set of tie points used and some other factors. In this study, only the interval of tie points is considered. This means that other factors are kept unchanged. Four pairs of SAR images with size of 1760 × 400 pixels were used for testing. The effects are assessed by a relative measure for the quality of the resultant interferogram and an absolute measure for the accuracy of the resultant DEM. Results show that the effect of tie point interval on the accuracy of the final DEM is not linear. When the tie point interval is smaller than 273 × 44 pixels (273 pixels in row and 44 pixels in column), the variation in the resultant DEM accuracy is not significant. It is also noticeable that an interval of 205 × 34 pixels always results in the best or very good results. Therefore, it seems that an interval of around 200 × 30 pixels (200 pixels in row and 30 pixels in column) is an appropriate choice for the selection of tie points for image co‐registration in hilly areas.