A fast and precise registration method for repeat-pass interferometric ALOS PALSAR data through baseline estimation

The precise co-registration is a premise in repeat-pass interferometric SAR (In-SAR) applications. To obtain a sub-pixel registration, the correlation coefficient of image patches is usually used to find the tie points in the re-sampled images. This procedure is computationally-expensive with a lot of re-sampling operations. Thus, an automatic gross registration is needed to reduce the times of re-sampling operations before the fine registration. In order to geometrically register the reference and repeat-pass data, the records of the satellite orbit and imaging geometry can be used. However, when this method is applied to repeat-pass ALOS PALSAR data, there is an offset of 20–30 pixels in the azimuth direction. As the interference baseline needs to be established before In-SAR information is derived, it is found that the positions of the satellite can be used to register the reference and repeat-pass data in the azimuth direction with less than one pixel offset. In this paper, this method was applied to a pair of ALOS PALSAR images acquired in northern Toronto, Ontario, Canada, on October 8^th and November 23^rd in 2008. The experimental result shows that the proposed method can obviously reduce the amount of the re-sampling operations and decrease the cost of computation.