نتایج جستجو برای: مدلهای غیر شعاعی sar

تعداد نتایج: 94029  

Journal: :The Plant cell 2008
Nancy Hofmann

Systemic acquired resistance (SAR) is a response to pathogen infection that renders plants more resistant to subsequent infection (reviewed in Grant and Lamb, 2006). It is characterized by salicylic acid (SA) accumulation both at the initial point of infection and throughout the plant and involves the induction of certain pathogenesis-related (PR) genes. The plant hormone abscisic acid (ABA) is...

Journal: :EURASIP J. Adv. Sig. Proc. 2005
Mark L. Williams Mark Preiss

A theoretical model is developed to describe the interferometric coherency between pairs of SAR images of rough soil surfaces. The model is derived using a dyadic form for surface reflectivity in the Kirchhoff approximation. This permits the combination of Kirchhoff theory and spotlight synthetic aperture radar (SAR) image formation theory. The resulting model is used to describe the interferom...

2003
L. Ferro-Famil A. Reigber E. Pottier W. M. Boerner

Conventional SAR processing techniques generally assume that targets have a stationary behavior during the SAR integration. However, SAR sensors operating at lower frequencies, like Land P-band, have a wide antenna characteristic in azimuth; i.e. during the formation of the synthetic aperture, multiple squint-angles are integrated to build the full-resolution SAR image. In this paper, a fully p...

2010
Andrea Cantini Fabrizio Lombardini Matteo Pardini

Multibaseline (MB) SAR tomography (Tomo-SAR) is an advanced mode of SAR interferometry, allowing full 3D imaging of volumetric and layover scatterers along the azimuth, range and height dimensions. Recently, this technique has also been extended in a polarimetric sense (PolTomo-SAR), exploiting MB SAR data acquired with different polarization channels. In this way, the joint estimation is possi...

2015
Ling Wang Birsen Yazıcı H Cagri Yanik

Antenna trajectory or motion errors are pervasive in synthetic aperture radar (SAR) imaging. Motion errors typically result in smearing and positioning errors in SAR images. Understanding the relationship between the trajectory errors and position errors in reconstructed images is essential in forming focused SAR images. Existing studies on the effect of antenna motion errors are limited to cer...

پایان نامه :وزارت علوم، تحقیقات و فناوری - دانشگاه یزد - دانشکده منابع طبیعی 1389

چکیده افزایش جمعیت و لزوم افزایش تولیدات کشاورزی استفاده از آب هایی با کیفیت پایین را جهت آبیاری در مناطق خشک اجتناب ناپذیر می کند. از طرفی دیگر اینگونه آب ها باعث تخریب خصوصیات فیزیکی و شیمیایی خاک می شوند. در این تحقیق به بررسی استفاده از آب های شور بر نسبت جذب سدیم (sar) خاک های منطقه حسین آباد دشت یزد- اردکان پرداخته شده است. جهت انجام تحقیق از اراضی که با آب های با کیفیت مختلف شامل: آب ...

2006
Huadong Guo

The Spaceborne Imaging Radar-c/X-band Synthetic Aperture Radar (SIR-C/X-SAR) mission was a cooperative endeavor of the United States, Germany, and Italy. The SIR-C/X-SAR scientific research program was a large international cooperative program of radar for Earth observation in which 13 countries participated, including China. SIR-C/X-SAR, with the ability to acquire polarimetric SAR and integer...

2007
Maurice Rüegg Daniel Nüesch Alois Rüegg

Ground moving target indication (GMTI) for synthetic aperture radar (SAR) provides information on non-static objects in radar imagery of a static ground scene. While general applications cover a wide area of topics from ocean current measurements to glacier ice flow, millimeter wave (mmW) SAR is well suited for traffic monitoring, reconnaissance, and identification of special target movements i...

Journal: :Ecology 2013
Fangliang He Stephen Hubbell

Researchers commonly use species-area relationships (SAR) to estimate extinction rates caused by habitat loss by reversing the SAR, extrapolating backward from area to calculate expected species loss. We have previously shown that the backward SAR method considerably overestimates extinction rates due to a previously unrecognized sampling artifact. Jacob Bock Axelsen, Uri Roll, Lewi Stone, and ...

1998
Jose G. Gonzalez Mark J. T. Smith Ingo S. Hontsch Lina J. Karam Kamesh Namuduri Harold Szu

This paper treats the compression of Synthetic Aperture Radar (SAR) imagery. SAR images are di cult to compress, relative to natural images, because SAR contains an inherent high frequency speckle. Today's state-of-the-art coders are designed to work with natural images, which have a lower frequency content. Thus, their performance on SAR is under par. In this paper we give an overview performa...

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