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Kim, Y.

Publications and source records attributed to Kim, Y..

At least 73 records · Page 4
All sourcesNASA NTRSDOE OSTI
NASA NTRS2002

On the relationshop between polarimetric parameters and soil moisture

In this paper, we examine the relationship between polarimetric parameters and soil moisture. For example, the co-polarization ratio is independent of surface roughness to the first order of the small perturbation approximation. As surface roughness increases, it can be shown that the co-polarization ratio depends on the surface slope under the tilted Bragg approximation. The coupling of the surface roughness to the co-polarization ratio is theoretically investigated. An algorithm to compensate the surface slope effect will be discussed. We will also study other polarimetric parameters such as the average alpha angle and eigenvalues to understand their relationship with soil moisture.

polarimetric parameters soil moisture↗
NASA NTRS2001

Machine vision guided sensor positioning system for leaf temperature assessment

A sensor positioning system was developed for monitoring plants' well-being using a non-contact sensor. Image processing algorithms were developed to identify a target region on a plant leaf. A novel algorithm to recover view depth was developed by using a camera equipped with a computer-controlled zoom lens. The methodology has improved depth recovery resolution over a conventional monocular imaging technique. An algorithm was also developed to find a maximum enclosed circle on a leaf surface so the conical field-of-view of an infrared temperature sensor could be filled by the target without peripheral noise. The center of the enclosed circle and the estimated depth were used to define the sensor 3-D location for accurate plant temperature measurement.

NASA Discipline Life Support Systems↗
NASA NTRS2001

Polarimetric and Interferometric SAR Calibration Verification Methods

It is necessary to calibrate SAR data in order to use the data for science applications. When both polarimetric and interferometric data are collected simultaneously, these SAR data can be used for cross-calibration and verification.

SAR calibration SAR polarimetry SAR interferometry↗
NASA NTRS2001

Comparison of Forest Parameter Estimation Techniques Using SAR Data

It is important to monitor forests in order to understand the impacts of global climate changes on terrestrial ecosystems. To characterize the forest changes, it is useful to parameterize a forest using several parameters.

SAR polarimetry SAR interferometry forest paramete↗
NASA NTRS2001

A quantitative comparison of soil moisture inversion algorithms

This paper compares the performance of four bare surface radar soil moisture inversion algorithms in the presence of measurement errors. The particular errors considered include calibration errors, system thermal noise, local topography and vegetation cover.

soil moisture↗
NASA NTRS2000

A New Coherent Radar for Ice Sounding in Greenland

This paper will discuss a new multifrequency dual channel coherent radar depth sounder for sounding ice. This sounder is unique since it is a fully coherent chirp radar design to operate at low (1500') as well as high altitudes (30,000').

radar↗