As one of the most densely populated and rapidly growing metropolitan areas worldwide, Guangdong-Hong Kong-Macao Greater Bay Area (GBA) China has been developing extensive metro networks to relieve escalating traffic congestion inner cities shorten public transport time inter cities. Metro construction possibly triggers ground deformation, which may result in damage tunnel, pipeline, structures. Fast efficient monitoring deformation along lines is vital not only itself but also these This...

Terrestrial laser scanning (TLS) can accurately and thoroughly document the actual geometrical deformations surface conditions of metro tunnel structures using high-density point clouds. In addition, TLS record backscattered intensity values each simultaneously. Backscattered are significant measures spectral property scanned objects in near-infrared region electromagnetic spectrum. The water leakage regions theoretically lower than those background because high absorption coefficient Thus,...

Coastal regions are increasingly vulnerable to ground deformation hazards, which can cause structural damage and amplify flood risks. Accurately monitoring the evolution of such is crucial for hazard assessment. However, precision multi-temporal interferometric synthetic aperture radar (MT-InSAR), a powerful geodetic technique mapping deformation, often compromised by atmospheric phase screen (APS) effect. This more serious in coastal zones, where it bias detection turning points mislead...

Abstract The detailed spatial variations of strain accumulation and creep on major faults in the northern San Francisco Bay Area (North Bay), which are important for seismic potential evaluation natural hazards, remain poorly understood. Here we combine interferometric synthetic aperture radar data from ERS‐1/2 Envisat satellites between 1992 2010 with continuous campaign GPS to obtain a high temporal coverage ground deformation North Bay. SAR both ascending descending orbits combined...

Many geological hazards are associated with ground deformations. Prompt and accurate detection interpretation of deformation is therefore vital to geohazard mitigation. Multitemporal Interferometric Synthetic Aperture Radar (MT-InSAR) an effective geodetic technique for monitoring deformation. However, computation using InSAR often hindered by various errors a lack expert knowledge. We present new advanced deep learning model based on multi-task vision transformer (MT-ViT) automatically...

Astigmatism can lead to meridional amblyopia, an orientation-specific visual deficit. This study investigated the effects of astigmatism on anisotropy in contrast sensitivity (CS) and steady-state evoked potential (ssVEP) across a range spatial frequencies. Thirty-two young adults with best-corrected distance acuity logMAR 0 or better were categorized into two groups: highly astigmatic (HAS, n = 16) spherical-equivalent error (SE) ≥ -6.00 D cylindrical (Cyl) 2.00 DC, non-astigmatic (NAS, SE...

The accuracy of phase unwrapping in multi-temporal interferometric synthetic aperture radar (MT-InSAR) technology affect closely on the ground deformation monitoring. In urban area, infrastructures such as high-rise buildings present additional challenges to due sudden elevation changes. failure rate is often much higher areas, bringing more biases estimated and height values. We propose a new method for MT-InSAR especially monitoring areas. isolates propagation path information by...

Coherent point (including persistent and distributed scatterers) selection phase ambiguity treatment (or parameter estimation) are the key tasks involved in multitemporal InSAR (MTInSAR) algorithms, which usually conducted separately with empirical thresholds. It is not rare to see that due discrepancies on threshold setting, even for same MTInSAR technique data sets, it will raise different (sometimes quite notable) results affect applicability of techniques. We propose here an integrated...

Ground deformation related to mining activities may occur immediately or many years later, leading a series of mine geological disasters, such as ground fissures, collapses, and even earthquakes. Deformation monitoring has been carried out with techniques, multitemporal interferometric synthetic aperture radar (MTInSAR). Over the past decade, MTInSAR widely used in deformation, it is still difficult retrieve over dense vegetation areas. In this study, we use multiple-platform SAR images The...

Underground constructions are implemented in cities to relieve the pressure of urbanization. Ground deformation often occurs with improper construction activities. Such can be measured techniques such as multitemporal interferometric synthetic aperture radar (MT-InSAR). However, anomalies building horizontal tilt cause MT-InSAR line-of-sight (LOS) tend zero, deformed area is likely ignored when individual SAR dataset applied. In this study, we explore induced by underground To Kwa Wan (TKW)...

Discriminating leaf and wood components in terrestrial laser scanning (TLS) point clouds is a prerequisite for accurately estimating 3-D structural biophysical attributes of both individual trees entire forests. However, most existing separation methods are conducted at local (i.e., or plot) level. The level need presegmentation the acquired clouds, accuracy reliability greatly influenced by forest occlusion effect cloud qualities. A new generalized method merely based on differences...

This study employed remote sensing (optical and synthetic aperture radar) data analysis techniques to quantify vertical ground displacements assess their contribution coastline erosion. To provide evidence from Pakistan, we selected the coast of Karachi—a mega-city located along dynamic Indus River Delta—which has been experiencing severe coastal erosion during last few decades. Observations C-band Envisat/ASAR Sentinel-1A sensors over 2004–2010 2014–2016 periods, respectively, enabled us in...

Phase decorrelation, as one of the main error sources, limits capability interferometric synthetic aperture radar (InSAR) for deformation mapping over areas with low coherence. Although several methods have been realized to reduce decorrelation noise, example, by phase linking and spatial temporal filters, their performances deteriorate when coherence estimation bias exists. We present an arc-based approach that allows reconstructing unwrapped interval time-series based on iterative weighted...

Land subsidence, as one of the engineering geological problems in world, is generally caused by compression unconsolidated strata due to natural or anthropogenic activities. We employed interferometric point target analysis (IPTA) a multi-temporal synthetic aperture radar (MT-InSAR) technique on ascending and descending Sentinel-1A terrain observation with progressive scans SAR (TOPSAR) images acquired between January 2015 December 2018 analyze spatio-temporal distribution cause subsidence...

Interferometric synthetic aperture radar (InSAR) is one of the most popular geodetic techniques for studying earthquake-related crustal displacements. Satellite SAR signals interact with ionosphere when they travel through it during time. The condition and its variation can significantly affect spaceborne InSAR measurements. In this letter, we use Advanced Land Observation Phase Array-Type L-band data from 2009 southern Sumatra earthquake to evaluate effects ionospheric artifacts on slip...

Urban infrastructure is an important part of supporting the daily operation a city. The stability subject to various deformations related disasters, engineering activities, and loadings. Regular monitoring such critical identify potential risks take timely remedial actions. Among advanced geodetic technologies available, radar interferometry has been widely used for due its extensive coverage, high spatial resolution, accurate deformation measurements. Specifically, spaceborne InSAR...

Ground based interferometric radar (GBIR) is a revolutionary advanced measurement technique for geoscience and engineering geodesy. It powerful temporally spatially dense measurements of highly dynamic target with sub-millimetric accuracy, especially in man-made structures, e.g. buildings, towers, dams bridges. In this case study, we use real aperture system, the Gamma Portable Radar Interferometer (GPRI-II), to perform near-real-time deformation monitoring deck (back side) cable-stayed...

The paper researches on the relationship between image quality and performance of interest point detection. In this paper, we use metrics repeatability as measures detection respectively. Considering differences image's scene degradation factor, nine images covering three kinds classic scenes are selected experiment data, they respectively contaminated by Gaussian blur noise. results show that have a certain quantitative relationship, is reduced with decrease metrics. Moreover, can be...