Impact of SAR Image Resolution on Polarimetric Persistent Scatterer Interferometry With Amplitude Dispersion Optimization

Abstract

Polarimetric persistent scatterer interferometry (PolPSI) takes advantage of polarimetric optimization algorithms that enhance interferograms' phase quality by adequately combining the available polarization channels (e.g., HH, VV, HV, and VH) into an improved one. Amplitude dispersion ( D A ) is one of the commonly used phase quality metrics for this optimization. The resolution of the images is supposed to have an impact on the performance of D A -based PolPSI in terms of both pixel density and quality. In this research, this impact is investigated. Specifically, 30 quad-pol RADARSAT-2 images over Barcelona with a resolution around 5 m in both range and azimuth are employed to generate additional data sets with degraded resolutions, ranging from 7.5 to 20 m. The results confirm that, in all cases, the ability of D A to select high-quality pixels, i.e., persistent scatterers, decreases when the spatial resolution worsens because the loss of resolution increases the number of scatterers present in a resolution cell. In addition, it would be expected that the performance of the polarimetric optimization of D A would tend to decrease when the spatial resolution worsens. However, for all employed resolutions, the polarimetric optimization improves the density and quality of PSs with respect to that of any single polarimetric channel. Moreover, this improvement is more noticeable, in relative terms, as the image resolution degrades.

Assessment of the Contribution of Polarimetric Persistent Scatterer Interferometry on Sentinel-1 Data

“…7), whereas the city centre is stable. This result is in accordance with previous studies [13], [15]- [17], [29].…”

“…A wide variety of scenarios are present in this region, i.e., airport, harbour, and urban areas which exhibit diverse orientations of streets and buildings with respect to the acquisition geometry. Ground deformation is expected over some areas due to settlement of recent constructions and in the harbour, as it has been reported in the past [17], [29].…”

Polarimetric Persistent Scatterer Interferometry for Ground Deformation Monitoring with VV-VH Sentinel-1 Data

“…Therefore, the existing PolPSI techniques could be employed for ground deformation monitoring over most places of the world with dual-pol Sentinel-1 data. However, as PolPSI algorithms' performances are affected by PolSAR images' resolution [40], the suitability of PolPSI with the medium resolution Sentinel-1 PolSAR images has to be investigated. In 2018, Roghayeh Shamshiri incorporates VH channel Sentinel-1 images with commonly used VV one for Trondheim city ground deformation monitoring using the PolPSI-ADI method, demonstrating the advantages of employing sentinel-1 dual-pol SAR images for PSI applications [41].…”

ACE-OT: Polarimetric SAR Data-Based Amplitude Contrast Enhancement Algorithm for Offset Tracking Applications

“…The differences in the results between Sentinel-1 and Radarsat-2 data can be mainly associated to the differences in the resolution: around 5.0 × 5.0 m for Radarsat-2 and 3.2 × 22.0 m for Sentinel-1. Low-resolution pixels then to increase speckle and mix the polarimetric features making more difficult its separation and categorization [21].…”