2010 M7.2 El Mayor–Cucapah Earthquake
Pixel offset tracking is an important complement to measure large ground displacements in both azimuth and range dimensions where SAR interferometry is not feasible. However, it is limited by redundant computation and incorrect estimations on decorrelated patches. We proposed a simple strategy that performs offset tracking on detected point-like targets (PT). We first detected image patches within bright PT using a sinc-like template from a single SAR image, and then performed offset tracking on them to estimate the shift of a PT. Compared with the standard method, the application on the 2010 M7.2 El Mayor–Cucapah earthquake shows that the proposed PT offset tracking can significantly increase the cross-correlation and thus result in both efficiency and reliability improvements [Hu et al., 2014, IEEE GRSL].
Figure 1. Comparison between the number of the prominent match patches of (a) standard and (b) PT offset tracking in sub-sampled grids. In (a) and (b), the color bar indicates the number of measurements in each 5 km × 5 km block. (c) and (d) Subsampled azimuth and range offsets from PT offset tracking in meters. In (c) and (d), the color bar indicates offsets in meters.
Figure 2. Master-slave cross-correlation comparison