2024-03-29T03:38:42Z
https://eoge.ut.ac.ir/?_action=export&rf=summon&issue=9128
Earth Observation and Geomatics Engineering
Earth Observ. Geomat. Eng.
2588-4352
2588-4352
2018
2
2
Feasibility Assessment of Exploitation of Distributed Scatterers in InSAR Stacks over Pasture Areas for Different SAR Satellite Missions
Sami
Samiei Esfahany
Ramon
Hanssen
During the last decades, time-series interferometric synthetic aperture radar (InSAR) has emerged as a powerful technique to measure various surface deformation phenomena of the earth. Early generations of time-series InSAR methodologies, i.e. Persistent Scatterer Interferometry (PSI), focused on point targets, which are mainly man-made features with a high density in urban areas and associated infrastructure. Later, methodologies were introduced aiming to extract information from other targets known as distributed scatterers (DS), which are associated with ground resolution cells occurring mainly in rural areas. For some terrain types, such as agricultural terrain or pastures, the feasibility of DS-methodologies is not straightforward. In this paper, we investigate the feasibility of DS exploitation in pasture areas over a case study area over a solution salt mining-induced subsidence field in Veendam, the Netherlands. Based on the temporal coherence behavior of the DS-pixels in the pasture areas, we assess the feasibility of exploiting the DS-pixels by different satellite missions. The results show that assuming a three-year stack of data, the information content in DS-pixels from current C-band and X-band missions is not enough for the successful utilization of their entire time-series. However by using intermittent series, e.g., by processing individual coherent periods, the results indicate that DS-pixels can be exploited: based on the proposed decorrelation model, the short repeat times of Sentinel-1 (6 or 12 days) results in a sufficient number of coherent interferograms over each winter period, enabling DS exploitation even over agricultural and pasture areas.
InSAR
Temporal decorrelation
Radar interferometry
Distributed scatterers
2018
12
01
64
73
https://eoge.ut.ac.ir/article_68754_10502fa38afbf8d8efae389e32591ea1.pdf
Earth Observation and Geomatics Engineering
Earth Observ. Geomat. Eng.
2588-4352
2588-4352
2018
2
2
Applicability analysis of the two-dimensional discrete wavelet transform for de-striping of GRACE products
Amirreza
Moradi
Ali
Ashrafzadeh Afshar
Gravity field models derived from the Gravity Recovery and Climate Experiment (GRACE) satellite mission are affected by the orbital arrangement of the satellites of this mission and the spatial dependence of the gravity field coefficients, which manifest themselves in the form of north to south strips in the maps of corresponding products. One of the common ways to deal with this phenomenon is to use a Gaussian filter to reduce the contribution of higher-order coefficients and to extract realistic images of the surface-mass variability. In this paper, the applicability of the two-dimensional wavelet transforms as a non-statistical method to reduce the effect of vertical components in GRACE products including the mentioned strips, has been tested and the results for different levels of transformation, as well as for using various base functions have been evaluated and this results have been compared with the result of applying Gaussian filter on the data of mass change derived from GRACE in Iran. The results indicate that although the two-dimensional wavelet transform can inherently be used to reduce the striping error of images, the wavelet-based de-striping of GRACE products is at most as effective as using the Gaussian filter of 100km, while previous studies showed that the application of the Gaussian filter of 350km would be the optimal radius to extract the hydrological signals in Iran. However in the case of wavelet transformation, the most important issue is the number of transformation levels such that applying the wavelet transforms at levels 3 and 4 have led to the closest results to the outputs of Gaussian filtering.
Grace
De-striping
Two-Dimensional wavelet transform
Applicability analysis
2018
12
01
74
81
https://eoge.ut.ac.ir/article_69193_071e31b4a5528d67b72bac00d17d87b8.pdf
Earth Observation and Geomatics Engineering
Earth Observ. Geomat. Eng.
2588-4352
2588-4352
2018
2
2
Firefly optimization algorithm for change detection in urban areas using remote sensing images
Mehdi
Moradi
Mahmoud Reza
Sahebi
Shaheen
Ghayourmanesh
change detection is an interesting topic for researchers, especially with the availability of high spatial resolution images. However, the use of high-resolution imagery increases variability within homogenous land-cover classes and leads to low-accuracy results. To overcome this problem and to generate a more accurate change mask, several features have been used and spatial information has been extracted from images. The firefly algorithm (FA), as one of the newest optimization algorithms for finding the optimum subspace, is then evaluated. The urban areas under study are Azadshahr (in Tehran province, Iran) and Shiraz (Iran). Two high-resolution images at two different time points are captured from each study area. To detect intra-class changes, a two-class classification of differential features is used, which also helps with the poor radiometric condition of the images (especially in Azadshahr images). The performance of the FA is then compared with a particle swarm optimization (PSO) algorithm and a genetic algorithm (GA). The results show that FA outperformed both PSO and GA algorithms with an overall accuracy and kappa coefficient of [95.17%, 0.90] versus [93.45%, 0.87] and [91.03%, 0.82] in Azadshahr study area and [94.87%, 0.90] versus [94.44%, 0.89] and [93.16%, 0.86] in Shiraz study area, respectively. The proposed methodology is also compared with the results of two other studies conducted on Azadshahr area and outperformed them as well. To analyze the contribution and importance of each feature type in change detection results, three indices, i.e. Effectiveness, Partial Effectiveness and Overall Effectiveness, are introduced in this paper. The result shows that features extracted from grey level co-occurrence matrix and features of other color spaces are the most effective features selected by FA to be used in change detection of high-resolution images; also these indices have revealed the weakness of using only spectral information for change detection of high-resolution images.
Firefly Algorithm
Change detection
Particle Swarm Optimization
genetic algorithm
Effectiveness Index
2018
12
01
82
99
https://eoge.ut.ac.ir/article_69194_eb9e0570595cbe7e4dcb7d0c6ea60073.pdf
Earth Observation and Geomatics Engineering
Earth Observ. Geomat. Eng.
2588-4352
2588-4352
2018
2
2
A Comparative Assessment of Selected Algorithms on Multi Domain Registration of Remote Sensing Images
Fatemeh
Alidoost
Hossein
Arefi
With the development of remotely sensed data acquisition techniques, the integration of complementary data has found a key role in many applications. The prerequisite of the data integration is the data registration. There are many approaches for image registration that they can be categorized based on the nature of data sources as the multi domain and single domain methods. The multi domain methods employ the data sources with different properties of gray values such as irradiance, the return strength of the laser pulse, and the height values. The different aspects of multi domain registration methods include the matching algorithm as feature-based or intensity-based, the level of automation, availability of initial registration parameters, the implementation cost, and so on. In this study, a number of multi domain registration algorithms are selected and compared based on the mentioned aspects and then, an automatic multi domain registration method is proposed to register an intensity image of LiDAR and a satellite image without using initial registration parameters. For this, the combination of the Scale Invariant Feature Transform (SIFT) detector and the mutual information theory is employed to use the strengths of both feature-based and intensity-based matching algorithms to decrease the difficulty of multi domain image registration. The final registration results prove that the combination of the feature-based and the intensity-based matching algorithms could be an efficient solution of multi domain image registration problem, especially for registration between the LiDAR intensity and the satellite images with the RMSE of one pixel.
Multi domain registration
Image matching
Mutual information
SIFT
LiDAR
2018
12
01
100
110
https://eoge.ut.ac.ir/article_69379_c24c49b40074d59acc0305410ec37666.pdf
Earth Observation and Geomatics Engineering
Earth Observ. Geomat. Eng.
2588-4352
2588-4352
2018
2
2
Displacement the Overlapping Sensors to Heal the Coverage Holes in a Wireless Sensor Network
Marjan
Ghanbari
Farid
Karimipour
Ali
Esmaeily
Providing a global coverage in wireless sensor networks with least possible numbers of sensor nodes has an important effect on the quality of a service and collection of information. Following a local approach, a set of nodes are first randomly distributed in the desired region, and then are moved or new nodes added iteratively until the existing holes are covered. In this study, a local approach is proposed, which improves an existing (tree-based) method for detecting coverage holes and adding new nodes. The advantage of the proposed approach is that the coverage holes are covered using the existing overlapping nodes as much as possible. It means, when a coverage hole is detected, the existing nodes with an overlapping coverage are detected and moved in order to cover the hole; new nodes are added only when required. The experimental results show the efficiency of the proposed method in terms of the number of nodes as well as the number of iterations and time complexity.
Wireless Sensor Network
Mobile Sensor Node
Coverage Hole
Tree-Base Method
Gravity Method
2018
12
01
111
117
https://eoge.ut.ac.ir/article_69965_173d134583016c4fb90298c7154480e7.pdf
Earth Observation and Geomatics Engineering
Earth Observ. Geomat. Eng.
2588-4352
2588-4352
2018
2
2
Determination of optimal gravity mission for the coseismic earthquake signals detection
Abolfazl
SHAHAMAT
The gravity field of the earth has temporal variations and our instruments are unfortunately defective and imperfect to measure that. Therefore, our knowledge of the gravity field of the earth is not complete. After launching satellite gravity missions, gravity data has been collected with a remarkable quality. One of the changes that takes place under the surface of the earth is a mass movement, which occurs as a result of several earthquakes. In the case of using multiple satellites, we might be able to achieve an additional amplification of the gravity signal through inter-satellite tracking between two low orbits. In this paper, five scenarios were simulated and compared with one another. For a better comparison, five different simulated faults in three deferent positions were considered to the orbit simulation scenarios. We also used the simulated data of both the earthquake and orbit propagation scenarios. In addition, we added normal noises in satellites orbit propagation step. Then, the 1964 earthquake caused by the Alaska () fault was investigated as a case study. For the Alaska fault, the seawater effect was considered, as well. The results indicated that the observations made by Helix and Pendulum scenarios had a better susceptibility to earthquake signals, and GRACE and GRACE-FO had the least susceptibility. Therefore, the radial track is considered to be an important part of observations as well as cross-track and along-track to be in the next order, respectively.
Earthquake signal
Gravity changing
Satellite gravity
Coseismic
Numerical simulation
2018
12
01
118
128
https://eoge.ut.ac.ir/article_70474_08831ebeaa20ce15e24103133392ed18.pdf