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We study the scattering of a vegetation canopy consisting of a large number of thin cylindrical scatterers using Numerical Maxwell Model in 3D Simulations (NMM3D). The full wave approach for solving Maxwell equations is based on the Foldy-Lax multiple scattering equations (FL) combined with the Method of Moments for bodies of revolution (BOR). The accuracy of the method FL-BOR is first validated by...
The aim of this research is to analyze the potential use of Global Navigation Satellite System (GNSS) signals for the monitoring of local vegetation characteristics. A new instrument, based on the use of a pair of low-cost receivers and antennas, providing continuous measurements of all the available Global Positioning System (GPS) satellite signals is proposed for the determination of signal attenuation...
Spaceborne SAR interferometry (InSAR) has the potential of mapping the forest height on a global scale and a monthly/weekly basis, which can improve our understanding of the global carbon dynamics. In previous work, repeat-pass SAR interferometry from spaceborne sensors is utilized to create large-scale forest height maps based on a newly developed approach. This paper thus serves as a summary paper...
Establishment of protected areas is one of the most important approaches for biodiversity conservation. Up to 2015, China has established 2740 sites for nature reserves with a total area of 1470300 km2, covering 14.8% of Chinese land surface. Based on remote sensing inversion, model simulation and spatial analysis methods, we analyzed spatial and temporal variations of habitat from the vegetation...
Sliding spotlight synthetic aperture radar (SAR) is a rising imaging mode, whose azimuth resolution is higher and imaged area is larger. When processing data, two key problems should be considered. Firstly, system's pulse repetition frequency (PRF) is always insufficient, which introduces aliasing into the azimuth spectrum. Secondly, the effect of motion error enhances because of longer synthetic...
In this work, a diversified deep structural metric learning is proposed for remote sensing image classification. Firstly, a deep structural metric learning is introduced to take full advantage of structural information of training batches. Secondly, we impose a diversity regularization over the factors of deep structural metric learning to encourage them to be uncorrelated, such that each factor tends...
Building extraction from remote sensing images is a longstanding topic in land use analysis and applications of remote sensing. Variations in shape and appearance of buildings, occlusions and other unpredictable factors increase the hardness of automatic building extraction. Numerous methods have been proposed during the last several decays, but most of these works are task oriented and lack of generalization...
This works presents a simplified Vertical Azimuth Display (VAD) motion simulator for off-shore wind lidars. The simulator is rooted to the case of a conically-scanning lidar (e.g., the Zephyr lidar), where the wind speed vector is retrieved from the Line-of-Sight velocities over one scan period. The methodological part addresses the geometrical foundations of the simulator and how the lidar attitude...
Monthly methane concentration (CH4) level over Zoige alpine wetland, China from October of 2002 to December of 2006 was analyzed based on the SCIAMACHY data. The level was low and might decrease from January to March then increase until August (except for 2006), and then decreased until fall or early winter. The linkage of the CH4, air temperature, precipitation, and soil temperature and moisture...
Synthetic Aperture Radar (SAR) remote sensing has become a valuable tool for maritime pollution monitoring with three major requirements: 1) low noise floor, 2) large area coverage, and 3) polarization diversity to maximize detection and discrimination of pollution features. In order to reconcile the advantages of fully polarimetric SAR with larger area coverage, compact polarimetry (CP) acquisitions...
In this paper, a superpixel-based segmentation method is proposed for PolSAR images by utilizing hierarchical region merging and segment refinement. The loss of the energy function, which determines the consistency of two adjacent regions from the statistical aspect, is applied to guide the merging procedure. In addition to the edge penalty term, the homogeneity measurement is also employed to prevent...
Within this paper we describe a methodology to retrieve ocean surface currents from video data of ocean surface waves. The video sequences were acquired at nadir by an off the shelf quadcopter in the range of visible light. The quadcopter is equipped with an actively controlled gimbal for stabilization of the video camera and records all the information needed to geocode the video data. The geocoded...
Recently the bistatic radar systems have seen increasing attention and development for the advantages in remote sensing of ocean surfaces. With the considerable merits of spatial diversity, bistatic systems supplement the retrieval of ocean physical parameters with conventional monostatic systems. For instance, an emerging bistatic radar technique, global navigation satellite signal reflectometry...
Based on laboratory experiments, the logarithmic dependence of X-band cross-polarized NRCS on wind friction velocity was found for high wind conditions. Using this dependency, surface drag parameterizations at hurricane wind and available collocated field data on radar backscattering and wind speed, the geophysical model function (GMF) as NRCS via 10-m wind speed is derived. The GMP is applicable...
In the coastal ocean, rivers provide a major source of biogeochemical, ecological, hydrographic and dynamical variability. Freshwater input by rivers produces buoyant low salinity plumes impacting ocean currents and stratification, which in turn influence air-sea heat exchange and oceanic vertical mixing. Rivers are also sources of nutrients and organic material, which can be transported far from...
This paper is dedicated to the “40 Years of Ocean Remote Sensing — a Session to Honor W. Alpers on the Occasion of his 80th Birthday”. In this paper, a list of Alpers' research contributions in understating the atmospheric gravity waves and oceanic internal waves are highlighted along with up-to-date research finding in these fields. On the atmospheric side, we presented the SAR observation of atmospheric...
An innovative method applied for suppression sidelobe in synthetic aperture radar (SAR) images is presented in this paper. The basic idea is to decompose the chirp signal into the unrelated chaos frequency modulation (CFM) signals uniformly in CFM space and add up their pulse compression results. As various CFM signal has different ideal thumbtack autocorrelation function, the energy from the sidelobe...
An adaptive speckle reduction algorithm for Polarimetric SAR (PolSAR) data, based on the combination of Gaussian Markov Random Field (GMRF) and Wavelet Edge Detection (WED) is proposed in this paper. The algorithm has three major steps: (a) first-time speckle reduction based on the GMRF model, (b) detail preservation using a WED approach, and (c) second-time speckle reduction using a least square...
Because of the large variety of sensors and spacecraft collecting data, planetary science needs to integrate various multisensor and multitemporal images. These multiple data represent a precious asset, as they allow the study of target spectral responses and of changes in the surface structure. Because of their variety, they also require accurate and robust registration. A new crater detection algorithm,...
In this paper, we focus on the 3D crater detection problem on lunar surface, which helps high-precision spacecraft landing and rover navigation in moon exploration projects. A random structured forests method is firstly applied to detect the 2D edges of craters, and then dense correspondence between CCD stereo images estimates the elevations of craters. Finally, we propose a 3D crater detection model,...
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