The ever-increasing amount of SAR data motivates the development of
automatic processing chains to fully exploit the opportunities offered
by these large databases.
The InSAR Mass processing Toolbox for Multidimensional time series
(MasTer) is an optimized tool to automatically download SAR data, select
the interferometric pairs, perform the interferometric mass processing,
compute the geocoded deformation maps, invert and display the velocity
maps and the 2D time series on a web page updated incrementally as soon
as a new image is available.
New challenges relate to data management and processing load. We address
them through methodological improvements dedicated to optimizing the
InSAR pair selection.
The proposed algorithm narrows the classical selection based on the
shortest temporal and spatial baselines thanks to a coherence proxy and
balances the use of each image as Primary and Secondary images thanks to
graph theory methods.
We apply the processing to three volcanic areas characterized with
different climate, vegetation and deformation characteristics: the
Virunga Volcanic Province (DR Congo), the Reunion Island (France) and
the Domuyo and Laguna del Maule area (Chile-Argentina border).
Compared to pair selection based solely on baseline criteria, this new
tool produces similar velocity maps while reducing the total number of
computed differential InSAR interferograms by up to
75\%, which drastically reduces the computation time.
The optimization also allows to reduce the influence of DEM errors and
atmospheric phase screen, which increase the signal-to-noise ratio of
the inverted displacement time series.