scholarly journals Refined Model-Based and Feature-Driven Extraction of Buildings from PolSAR Images

2019 ◽  
Vol 11 (11) ◽  
pp. 1379 ◽  
Author(s):  
Hui Fan ◽  
Sinong Quan ◽  
Dahai Dai ◽  
Xuesong Wang ◽  
Shunping Xiao

Polarimetric synthetic aperture radar (PolSAR) building extraction plays an important role in urban planning, disaster management, etc. In this paper, a building extraction method using refined model-based decomposition and robust scattering feature is proposed. On the one hand, the newly proposed refined five-component decomposition and its derived scattering powers are applied to detect the buildings. On the other hand, by combining the matrix elements and co-polarization correlation coefficient, a robust feature is proposed to discriminate buildings and non-buildings. Both these two preliminary extraction results are obtained through thresholding segmentation. Finally, they are fused via the HX Markov random fields so as to further improve the extraction accuracy. The performance of the proposed method is demonstrated and evaluated with Gaofen-3 and uninhabited aerial vehicle SAR full PolSAR data over different test sites. Outputs show that the proposed method outperforms other state-of-the-art methods and provides an overall accuracy of over 90%.

2019 ◽  
Vol 11 (23) ◽  
pp. 2802 ◽  
Author(s):  
Hui Fan ◽  
Sinong Quan ◽  
Dahai Dai ◽  
Xuesong Wang ◽  
Shunping Xiao

Due to incomprehensive and inaccurate scattering modeling, the state-of-the-art polarimetric synthetic aperture radar (PolSAR) model-based target decompositions are incapable of effectively depicting the scattering mechanism of obliquely oriented urban areas. In this paper, a seven-component model-based decomposition scheme is proposed by constructing several sophisticated scattering models. First, an eigenvalue-based obliquely-oriented dihedral scattering model is presented to reasonably distribute the co-polarization and cross-polarization scattering powers in obliquely oriented urban areas, thus accurately characterizing the urban scattering. Second, the ±45° oriented dipole and ±45° quarter-wave reflector scattering models are incorporated for the purpose of accounting for the real and imaginary components of the T 13 element in the coherency matrix so as to fully utilize polarimetric information. Finally, according to their mathematical forms, several strategies for model parameter solutions are designed, and the seven-component decomposition is fulfilled. Experimental results conducted on different PolSAR data demonstrate that the proposed method considerably improves the PolSAR scattering interpretation in a more physical manner compared to other existing model-based decomposition, which can be applied for urban area detection, classification, and other urban planning applications.


Author(s):  
E. Kiana ◽  
S. Homayouni ◽  
M. A. Sharifi ◽  
M. R. Farid-Rohani

Abstract. This paper investigates and compares the potential of five model-based polarimetric decompositions, namely those developed by Eigenvector-based decomposition (Van Zyl), Model-based decomposition (Freeman-Durden three-component decomposition and Yamaguchi four-component decomposition), An & Yang3 and An & Yang4 for crop biomass detection over agricultural fields covered by various crops. The time series of Uninhabited Aerial Vehicle Synthetic Aperture Radar (UAVSAR) data and the ground truth of soil and vegetation characteristics collected during the Soil Moisture Active Passive (SMAP) Validation Experiment in 2012 (SMAPVEX12) were used to compare the five decomposition methods with related to the scattering mechanisms and the biomass retrieval performances. The results show that the performance of each decomposition method for biomass retrieval depends on the crop types and the crop phenological stages. Finally, an overall biomass underestimation was observed from the five decompositions, and the highest regression value of 99% was obtained from Freeman decomposition as a result of the enhanced volume scattering. Indeed, Freeman-Durden model provided the best results.


Author(s):  
M. R. Pinnel ◽  
A. Lawley

Numerous phenomenological descriptions of the mechanical behavior of composite materials have been developed. There is now an urgent need to study and interpret deformation behavior, load transfer, and strain distribution, in terms of micromechanisms at the atomic level. One approach is to characterize dislocation substructure resulting from specific test conditions by the various techniques of transmission electron microscopy. The present paper describes a technique for the preparation of electron transparent composites of aluminum-stainless steel, such that examination of the matrix-fiber (wire), or interfacial region is possible. Dislocation substructures are currently under examination following tensile, compressive, and creep loading. The technique complements and extends the one other study in this area by Hancock.The composite examined was hot-pressed (argon atmosphere) 99.99% aluminum reinforced with 15% volume fraction stainless steel wire (0.006″ dia.).Foils were prepared so that the stainless steel wires run longitudinally in the plane of the specimen i.e. the electron beam is perpendicular to the axes of the wires. The initial step involves cutting slices ∼0.040″ in thickness on a diamond slitting wheel.


2021 ◽  
Vol 2021 (2) ◽  
Author(s):  
Ashoke Sen

Abstract In a recent paper, Balthazar, Rodriguez and Yin found remarkable agreement between the one instanton contribution to the scattering amplitudes of two dimensional string theory and those in the matrix model to the first subleading order. The comparison was carried out numerically by analytically continuing the external energies to imaginary values, since for real energies the string theory result diverges. We use insights from string field theory to give finite expressions for the string theory amplitudes for real energies. We also show analytically that the imaginary parts of the string theory amplitudes computed this way reproduce the full matrix model results for general scattering amplitudes involving multiple closed strings.


Pharmaceutics ◽  
2021 ◽  
Vol 13 (6) ◽  
pp. 816
Author(s):  
Yuxuan Ge ◽  
Zhenhua Hu ◽  
Jili Chen ◽  
Yujie Qin ◽  
Fei Wu ◽  
...  

GLP-1 receptor agonists are a class of diabetes medicines offering self-regulating glycemic efficacy and may best be administrated in long-acting forms. Among GLP-1 receptor agonists, exenatide is the one requiring the least dose so that controlled-release poly(d, l-lactic-co-glycolic acid) (PLGA) microspheres may best achieve this purpose. Based on this consideration, the present study extended the injection interval of exenatide microspheres from one week of the current dosage form to four weeks by simply blending Mg(OH)2 powder within the matrix of PLGA microspheres. Mg(OH)2 served as the diffusion channel creator in the earlier stage of the controlled-release period and the decelerator of the self-catalyzed degradation of PLGA (by the formed lactic and glycolic acids) in the later stage due to its pH-responsive solubility. As a result, exenatide gradually diffused from the microspheres through Mg(OH)2-created diffusion channels before degradation of the PLGA matrix, followed by a mild release due to Mg(OH)2-buffered degradation of the polymer skeleton. In addition, an extruding–settling process comprising squeezing the PLGA solution through a porous glass membrane and sedimentation-aided solidification of the PLGA droplets was used to prepare the microspheres to ensure narrow size distribution and 95% encapsulation efficiency in an aqueous continuous phase. A pharmacokinetic study using rhesus monkey model confirmed the above formulation design by showing a steady blood concentration profile of exenatide with reduced CMAX and dosage form index. Mg·(OH)2


Sensors ◽  
2019 ◽  
Vol 19 (21) ◽  
pp. 4644 ◽  
Author(s):  
Naus ◽  
Marchel ◽  
Szymak ◽  
Nowak

The paper presents the results of research on assessing the accuracy of angular position measurement relative to the sea horizon using a camera mounted on an unmanned bathymetric surveying vehicle of the Unmanned Surface Vehicle (USV) or Unmanned Aerial Vehicle (UAV) type. The first part of the article presents the essence of the problem. The rules of taking the angular position of the vehicle into account in bathymetric surveys and the general concept of the two-camera tilt compensator were described. The second part presents a mathematical description of the meters characterizing a resolution and a mean error of measurements, made on the base of the horizon line image, recorded with an optical system with a Complementary Metal-Oxide Semiconductor (CMOS) matrix. The phenomenon of the horizon line curvature in the image projected onto the matrix that appears with the increase of the camera height has been characterized. The third part contains an example of a detailed analysis of selected cameras mounted on UAVs manufactured by DJI, carried out using the proposed meters. The obtained results including measurement resolutions of a single-pixel and mean errors of the horizon line slope measurement were presented in the form of many tables and charts with extensive comments. The final part presents the general conclusions from the performed research and a proposal of directions for their further development.


1993 ◽  
Vol 6 (1) ◽  
pp. 61-80 ◽  
Author(s):  
John D'Arcy May

Do human rights in their conventional, Western understanding really meet the needs of Pacific peoples? This article argues that land rights are a better clue to those needs. In Aboriginal Australia, Fiji, West Papua and Papua New Guinea, case studies show that people's relationship to land is religious and implicitly theological. The article therefore suggests that rights to land need to be supplemented by rights of the land extending to the earth as the home of the one human community and nature as the matrix of all life.


2011 ◽  
Vol 2011 ◽  
pp. 1-11 ◽  
Author(s):  
Matthew Rhudy ◽  
Yu Gu ◽  
Jason Gross ◽  
Marcello R. Napolitano

Using an Unscented Kalman Filter (UKF) as the nonlinear estimator within a Global Positioning System/Inertial Navigation System (GPS/INS) sensor fusion algorithm for attitude estimation, various methods of calculating the matrix square root were discussed and compared. Specifically, the diagonalization method, Schur method, Cholesky method, and five different iterative methods were compared. Additionally, a different method of handling the matrix square root requirement, the square-root UKF (SR-UKF), was evaluated. The different matrix square root calculations were compared based on computational requirements and the sensor fusion attitude estimation performance, which was evaluated using flight data from an Unmanned Aerial Vehicle (UAV). The roll and pitch angle estimates were compared with independently measured values from a high quality mechanical vertical gyroscope. This manuscript represents the first comprehensive analysis of the matrix square root calculations in the context of UKF. From this analysis, it was determined that the best overall matrix square root calculation for UKF applications in terms of performance and execution time is the Cholesky method.


2010 ◽  
Vol 2010 ◽  
pp. 1-9 ◽  
Author(s):  
Juntong Qi ◽  
Dalei Song ◽  
Lei Dai ◽  
Jianda Han ◽  
Yuechao Wang

This paper describes recent research on the design, implement, and testing of a new small-scaled rotorcraft Unmanned Aerial Vehicle (RUAV) system—ServoHeli-40. A turbine-powered UAV weighted less than 15 kg was designed, and its major components were tested at the Shenyang Institute of Automation, Chinese Academy of Sciences in Shenyang, China. The aircraft was designed to reach a top speed of more than 20 mps, flying a distance of more than 10 kilometers, and it is going to be used as a test-bed for experimentally evaluating advanced control methodologies dedicated on improving the maneuverability, reliability, as well as autonomy of RUAV. Sensors and controller are all onboard. The full system has been tested successfully in the autonomous mode using the multichannel active modeling controller. The results show that in a real windy environment the rotorcraft UAV can follow the trajectory which was assigned by the ground control station exactly, and the new control method is obviously more effective than the one in the past year's research.


Author(s):  
Ori Soltes

Religious and cultural syncretism, particularly in visual art in the Jewish and Christian traditions since the 19th century, has expressed itself in diverse ways and reflects a broad and layered series of contexts. These are at once chronological—arising out of developments that may be charted over several centuries before arriving into the 19th and 20th centuries—and political, spiritual, and cultural, as well as often extending beyond the Jewish–Christian matrix. The specific directions taken by syncretism in art is also varied: it may be limited to the interweave of two religious traditions—most often Jewish and Christian—in which most often it is the minority artist seeking ways to create along lines consistent with what is created by the majority. It may also interweave three or more traditions. It may be a matter of religion alone, or it may be a matter of other issues, such as culture or gender, which may or may not be obviously intertwined with religion. The term “syncretism” has, in certain specifically anthropological and theological circles, acquired a negative connotation. This has grown out of the increasing consciousness, since the 1960s, of the political implications of that term in the course of Western history, in which hegemonic European Christianity has addressed non-Christian religious perspectives. This process intensified in the Colonial era when the West expanded its dominance over much of the globe. An obvious and particularly negative instance of this is the history of the Inquisition as it first affected Jews in late-15th-century Spain and later encompassed indigenous peoples in the Americas, Asia, and Africa. While this issue is noted—after all, art has always been interwoven with politics—it is not the focus of this article. Instead “syncretism” will not be treated as a concept that needs to be distinguished from “hybridization” or “hybridity,” although different modes of syncretism will be distinguished. Syncretistic preludes to visual artists in the 19th and 20th centuries, suggesting some of the breadth of possibility, include Pico della Mirandola, Kabir, and Baruch/Benedict Spinoza. Specific religious developments and crises in Europe from the 16th century to the 18th century brought on the emancipation of the Jews in some places on the one hand, and a contradictory continuation of anti-Jewish prejudice on the other, the latter shifting from a religious to a racial basis. This, together with evident paradoxes regarding secular and spiritual perspectives in the work of key figures in the visual arts, led to a particularly rich array of efforts from Jewish artists who revision Jesus as a subject, applying a new, Jewishly humanistic perspective to transform this most traditional of Christian subjects. Such a direction continued to spread more broadly across the 20th century. The Holocaust not only raised new visual questions and possibilities for Jewish artists, but also did so from the opposite direction for the occasional Christian—particularly German—artist. Cultural syncretism sometimes interweaves religious syncretism—which can connect and has connected Christianity or Judaism to Eastern religions—and a profusion of women artists in the last quarter of the century has added gender issues to the matrix. The discussion culminates with Siona Benjamin: a Jewish female artist who grew up in Hindu and Muslim India, attended Catholic and Zoroastrian schools, and has lived in America for many decades—all these aspects of her life resonate in her often very syncretistic paintings.


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