17 October 2013 Robust tie points selection for InSAR image coregistration
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Image coregistration is an important step in SAR interferometry which is a well known method for DEM generation and surface displacement monitoring. A practical and widely used automatic coregistration algorithm is based on selecting a number of tie points in the master image and looking for the correspondence of each point in the slave image using correlation technique. The characteristics of these points, their number and their distribution have a great impact on the reliability of the estimated transformation. In this work, we present a method for automatic selection of suitable tie points that are well distributed over the common area without decreasing the desired tie points’ number. First we select candidate points using Harris operator. Then from these points we select tie points depending on their cornerness measure (the highest first). Once a tie point is selected, its correspondence is searched for in the slave image, if the similarity measure maximum is less than a given threshold or it is at the border of the search window, this point is discarded and we proceed to the next Harris point, else, the cornerness of the remaining candidates Harris points are multiplied by a spatially radially increasing function centered at the selected point to disadvantage the points in a neighborhood of a radius determined from the size of the common area and the desired number of points. This is repeated until the desired number of points is selected. Results of an ERS1/2 tandem pair are presented and discussed.
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Takieddine Skanderi, Takieddine Skanderi, Boulerbah Chabira, Boulerbah Chabira, Belkacem Afifa, Belkacem Afifa, Aichouche Belhadj Aissa, Aichouche Belhadj Aissa, "Robust tie points selection for InSAR image coregistration", Proc. SPIE 8892, Image and Signal Processing for Remote Sensing XIX, 88921B (17 October 2013); doi: 10.1117/12.2029248; https://doi.org/10.1117/12.2029248

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