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In this work we discuss the differences between SAR tomographic analyses produced by direct 3D focusing, which we refer to as coherent tomography, and by processing simultaneous interferometric pairs collected in different passes, which we refer to as incoherent tomography. While the application of coherent tomography using space-borne sensors is often hindered by temporal decorrelation, incoherent...
This study aims to evaluate the potential of coherent change detection using multi-temporal polarimetric interferometric SAR data. One of the limitations in damage area extraction is that the decorrelation caused by the disaster is commonly coupled with the natural changes. Also, the interpretation of the coherence is troublesome and requires the coherence model. The approach used in this study is...
We propose a method for generating precise digital elevation models from high resolution SAR data in PolInSAR, focusing on the pixel-by-pixel variety of scattering mechanisms. We show the effectiveness of the proposed method by using ALOS-2 SAR data.
The problem of image encryption on the telemedicine platform was discussed in this paper. The Arnold algorithm was introduced firstly, then based on the analyzing of those advantages and disadvantages in the encryption algorithm, a modified encryption algorithm was proposed by using the sensitivity of the initial value and the internal randomness of chaotic functions. Finally, effect evaluation was...
In this paper, we first determine the optimal window size for ALOS2-PALSAR2 data is 7 × 7. To preserve the accuracy of incoherent interpretation and the high resolution of original data, simultaneously, we proposed the combination use of various window sizes in Stokes vector based data interpretation. The experimental results show that the proposed method can provide interpretation results in success...
This article focuses on the mapping of fire burn scars, fire severity and soil erosion susceptibility using multi-sensoral satellite data. An automatic procedure for the mapping of fire affected areas and for the estimation of fire severity using Sentinel-2 data is presented. The Sentinel-2 based classification results are compared to a burn scar derived by a semi-automatic object-based approach using...
This paper briefly presents a case for a global wind pathfinder mission using the proven coherent DWL technology as a component in a global wind observing strategy that also includes CMV/AMV, OVW, CYGNSS, near-future small sats, etc. The proposed lower energy per pulse/high PRF coherent DWL addresses the challenge of making precise measurements in the presence of clouds.
In the multi-temporal InSAR technique, a deformation map is obtained by arc integration. Therefore, the reliability of an arc solution directly influences the precision of the final result. Many methods have been proposed to estimate arc parameters, but few have evaluated the arc quality. In this study, the influence of phase ambiguity is analyzed and two indicators are defined to identify the arcs...
On the 11th of August 2012 two earthquakes within 11 minutes struck NW Iran with considerable fatalities and damages. Four Synthetic Aperture Radar (SAR) images from Wide Multi-look Fine mode of RADARSAT-2 data have been considered for rapid damage assessment through SAR interferometry processing. All images are from ascending orbits with 8 m spatial resolution. The first pair (2012.04.13 and 2012...
The vertical structure of firn below the surface of the Greenland ice sheet is driven by meteorological conditions like the intensity and duration of melting periods. The formation of ice inclusions through meltrefreeze processes leads to strong scatterers whose vertical distribution influences interferometric coherences. Interferometric coherence profiles from quad-pol SAR data show clear sensitivity...
In this paper, we focus on the topographic effects of InSAR interferometric land use (ILU) images and a corresponding terrain correction method is proposed. Firstly, Effective scattering area correction and angular variation effect correction are performed for intensity information. Secondly, for the coherence information, a novel difference equation method of terrain correction based on the SINC...
This paper made a coherence analysis to access the ability of snow extraction based on the Terra-SAR X-HH data, and develop a method using multi-temporal coherence combined with the traditional method. Two pairs of Terra-SAR data with the same temporal baseline and similar spatial baseline were chosen, before and after snowfall. Traditional method was used to remove the snow free area with relative...
In order to overcome the influence of decorrelation phenomenon in multi-baseline InSAR techniques, the phase reconstruction technique has been developed in recent years and has become one of the hottest focuses in radar interferometry. In this paper, our recently developed simplified coherence network phase reconstruction technique is reported. With the use of Sentinel-1 data, it is firstly engaged...
In this paper we investigate interferometric pairs of SAR images acquired by Tandem-X with the monostatic pursuit and the alternative bistatic modes for sea ice segmentation. The individual SAR images are modelled as non-Gaussian, and from the modelled data different features are extracted, stacked together and clustered. The interferometric coherence is regarded as an additional feature and utilized...
Feature extraction is an important issue for image interpretation, many valuable feature extraction methods have been proposed to address synthetic aperture radar (SAR) image registration. However, the current methods care little about changes over multi-temporal SAR images, which result in unstable output features. The unstable property is a latent factor to affect the accuracy of SAR image registration...
Forest height is a key measurement for determining aboveground carbon in forests and forest biomass. DLR's TANDEM-X mission provides paired scenes that can be used for forest height measurement. We have demonstrated this in [1,2,3] for scenes with some moderate topography. This paper discusses issues for estimating forest canopy heights in mountainous terrain. Multiple dates and baselines of TanDEM-X...
Traditional dehazing techniques, as a well-studied topic in image processing, are now widely used to eliminate the haze effects from individual images. However, even the state-of-the-art dehazing algorithms may not provide sufficient support to video analytics, as a crucial pre-processing step for video-based decision making systems (e.g., robot navigation), due to the limitations of these algorithms...
In this paper we address various geometric properties of frames, such as spark, coherence, restricted isometry property, and frame order statistics. These properties play crucial role in various signal processing problems, including compressive sensing, phase retrieval, and quantization. We focus on a particular case of structured frames, namely on Gabor frames, where frame vectors are time and frequency...
We study the Orthogonal Greedy Algorithm (OGA) for frames in Hilbert spaces. Various approximate Parseval results for frames are also obtained. We also discuss the relationship between coherence and upper bound of frames. Finally, Lebesgue-type inequalities are proved so as to obtain upper estimates for the errors of the Orthogonal Greedy Algorithm for Riesz frames and frames which are norm bounded...
We report on a theoretical and experimental study performed on AlAs/GaAs micropillar cavities containing InGaAs quantum dots as active medium. The devices have the interesting property of having almost all emission (spontaneous and stimulated) channelled into one cavity mode. They are excellent experimental platforms for studying laser physics because their emission behaviours question our understanding...
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