• Title/Summary/Keyword: Remote sensing technique

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Development of Remote Sensing Reflectance and Water Leaving Radiance Models for Ocean Color Remote Sensing Technique (해색 원격탐사를 위한 원격반사도 및 수출광 모델의 개발)

  • 안유환
    • Korean Journal of Remote Sensing
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    • v.16 no.3
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    • pp.243-260
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    • 2000
  • Ocean remote sensing reflectance of just above water level was modeled using inherent optical properties of seawater contents, total absorption (a) and backscattering(bb) coefficients ($R_{rs}$=0.046 $b_b$/(a+$b_b$). This modeling was based on the specific absorption and backscattering coefficients of 5 optically active seawater components; phytoplankton pigments, non-chlorophyllous suspended particles, dissolved organic matters, heterotrophic microorganisms, and the other unknown particle components. Simulated remote sensing reflectance($R_{rs}$) and water leaving radiance(Lw) spectra were well agreed with in-situ measurements obtained using a bi-directional fields remote spectrometer in coastal waters and open ocean. $R_{rs}$ values in SeaWiFS bands from the model were analyzed to develop 2-band ratio ocean color chlorophyll with those observed insitu. Also, chlorophyll algorithm based on remote reflectance developed in this study fell in those obtained by a SeaBAM working group. The model algorithms were examined and compared with those observed insitu. Also, chlorophyll algorithm based on remote reflectance developed in this study fell in those obtained by a SeaBAM working group. The remote reflectance model will be very helpful to understand the variation of water leaving radiances caused by the various components in the seawater, and to develop new ocean color algorithm for CASE-II water using neural network method or other analytical method, and in the model of fine atmospheric signal correction.

RGB Composite Technique for Post Wildfire Vegetation Monitoring Using Sentinel-2 Satellite Data (산불 후 식생 회복 모니터링을 위한 Sentinel-2 위성영상의 RGB 합성기술)

  • Kim, Sang-il;Ahn, Do-seob;Kim, Seung-chul
    • Korean Journal of Remote Sensing
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    • v.37 no.5_1
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    • pp.939-946
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    • 2021
  • Monitoring of post wildfire provides important information for vegetation restoration. In particular, remote sensing data are known to provide useful information necessary for monitoring. However, there are insufficient research results which is monitoring the vegetation recovery using remote sensing data. This study is directed to monitoring post-wildfire vegetation restoration. It proposes a method for monitoring vegetation restoration using Sentinel-2 satellite data by compositing Tasseled Cap linear regression trend in a post wildfire study sites. Although it is a simple visualization technique using satellite images, it was able to confirm the possibility of effective monitoring.

New Simple Decomposition Technique for Polarimetric SAR Images (완전편파 SAR영상의 새로운 영상 분해 기법)

  • Lee, Kyung-Yup;Oh, Yi-Sok
    • Korean Journal of Remote Sensing
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    • v.26 no.1
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    • pp.1-7
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    • 2010
  • This paper proposes a new decomposition technique for polarimetric synthetic aperture radar (SAR) images. This new decomposition technique is based on the degree of polarization (DoP) and co-polarized phase-difference (CPD) of the measured polarimetric backscattering coefficients. This decomposition technique is compared with the existing three- and four-component decomposition techniques with the ALOS PALSAR full polarimetric L-band data acquired in 2009. It is shown that the new decomposition technique is better or comparable to the existing techniques for the study areas such as sea, bare soil, forest, and urban area.

Current status and prospects of plant diagnosis and phenomics research by using ICT remote sensing system (ICT 원격제어 system 이용 식물진단, Phenomics 연구현황 및 전망)

  • Jung, Yu Jin;Nou, Ill Sup;Kim, Yong Kwon;Kim, Hoy Taek;Kang, Kwon Kyoo
    • Journal of Plant Biotechnology
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    • v.43 no.1
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    • pp.21-29
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    • 2016
  • Remote Sensing (RS) is a technique to obtain necessary information in a non-contact and non-destructive method by using various sensors on the surface, water or atmospheric phenomena. These techniques combine elements such as sensors, and platform and information communication technology (ICT) for mounting the sensor. ICT has contributed significantly to the success of smart agriculture through quantification and measurement of environmental factors and information such as weather, crop and soil management to distribution and consumption stage, as well as the production stage by the cloud computer. Remote sensing techniques, including non-destructive non-contact bioimaging (remote imaging) is required to measure the plant function. In addition, bioimaging study in plant science is performed at the gene, cellular and individual plant level. Recently, bioimaging technology is considered the latest phenomics that identifies the relationship between the genotype and environment for distinguishing phenotypes. In this review, trends in remote sensing in plants, plants diagnostics and response to environment and status of plants phonemics research were presented.

Monitoring of the Volcanic Ash Using Satellite Observation and Trajectory Analysis Model (인공위성 자료와 궤적분석 모델을 이용한 화산재 모니터링)

  • Lee, Kwon-Ho;Jang, Eun-Suk
    • Korean Journal of Remote Sensing
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    • v.30 no.1
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    • pp.13-24
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    • 2014
  • Satellite remote sensing data have been valuable tool for volcanic ash monitoring. In this study, we present the results of application of satellite remote sensing data for monitoring of volcanic ash for three major volcanic eruption cases (2008 Chait$\acute{e}$n, 2010 Eyjafjallaj$\ddot{o}$kull, and 2011 Shinmoedake volcanoes). Volcanic ash detection products based on the Moderate Resolution Imaging Spectro-radiometer (MODIS) observation data using infrared brightness temperature difference technique were compared to the forward air mass trajectory analysis by the HYbrid Single-Particle Lagrangian Integrated Trajectory (HYSPLIT) model. There was good correlation between MODIS volcanic ash image and trajectory lines after the volcanic eruptions, which support the feasibility of using the integration of satellite observed and model derived data for volcanic ash forecasting.

Topography, Vertical and Horizontal Deformation In the Sulzberger Ice Shelf, West Antarctica Using InSAR

  • Kwoun Oh-Ig;Baek Sangho;Lee Hyongki;Sohn Hong-Gyoo;Han Uk;Shum C. K.
    • Korean Journal of Remote Sensing
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    • v.21 no.1
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    • pp.73-81
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    • 2005
  • We construct improved geocentric digital elevation model (DEM), estimate tidal dynamics and ice stream velocity over Sulzberger Ice Shelf, West Antarctica employing differential interferograms from 12 ERS tandem mission Synthetic Aperture Radar (SAR) images acquired in austral fall of 1996. Ice, Cloud, and land Elevation Satellite (ICESat) laser altimetry profiles acquired in the same season as the SAR scenes in 2004 are used as ground control points (GCPs) for Interferometric SAR (InSAR) DEM generation. 20 additional ICESat profiles acquired in 2003-2004 are then used to assess the accuracy of the DEM. The vertical accuracy of the OEM is estimated by comparing elevations with laser altimetry data from ICESat. The mean height difference between all ICESat data and DEM is -0.57m with a standard deviation of 5.88m. We demonstrate that ICESat elevations can be successfully used as GCPs to improve the accuracy of an InSAR derived DEM. In addition, the magnitude and the direction of tidal changes estimated from interferogram are compared with those predicted tidal differences from four ocean tide models. Tidal deformation measured in InSAR is -16.7cm and it agrees well within 3cm with predicted ones from tide models. Lastly, ice surface velocity is estimated by combining speckle matching technique and InSAR line-of-sight measurement. This study shows that the maximum speed and mean speed are 509 m/yr and 131 m/yr, respectively. Our results can be useful for the mass balance study in this area and sea level change.

Remote Impedance-based Loose Bolt Inspection Using a Radio-Frequency Active Sensing Node

  • Park, Seung-Hee;Yun, Chung-Bang;Inman, Daniel J.
    • Journal of the Korean Society for Nondestructive Testing
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    • v.27 no.3
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    • pp.217-223
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    • 2007
  • This paper introduces an active sensing node using radio-frequency (RF) telemetry. This device has brought the traditional impedance-based structural health monitoring (SHM) technique to a new paradigm. The RF active sensing node consists of a miniaturized impedance measuring device (AD5933), a microcontroller (ATmega128L), and a radio frequency (RF) transmitter (XBee). A macro-fiber composite (MFC) patch interrogates a host structure by using a self-sensing technique of the miniaturized impedance measuring device. All the process including structural interrogation, data acquisition, signal processing, and damage diagnostic is being performed at the sensor location by the microcontroller. The RF transmitter is used to communicate the current status of the host structure. The feasibility of the proposed SHM strategy is verified through an experimental study inspecting loose bolts in a bolt-jointed aluminum structure.

SUBPIXEL UNMIXING TECHNIQUE FOR DETECTION OF USEFUL MINERAL RESOURCES USING HYPERSPECTRAL IMAGERY

  • Hyun, Chang-Uk;Park, Hyeong-Dong
    • Proceedings of the KSRS Conference
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    • 2008.10a
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    • pp.66-67
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    • 2008
  • Most mineral resources are located in subsurface but mineral exploration starts with a step of investigation in wide-area to find evidence of buried ores. Conventional technique for exploration on wide-area as a preliminary survey is an observation using naked eyes by geologist or chemical analysis using lots of samples obtained from target area. Hyperspectral remote sensing can overcome those subjective and time consuming survey and can produce mineral resources distribution map. Precise resource map requires information of mineral distribution in a subpixellevel because mineral is distributed as rock components or narrow veins. But most hyperspectral data is composed of pixels of several meters or more than ten meters scale. We reviewed subpixel unmixing algorithms which have been used for geological field and tested detection ability with Hyperion imagery, geological map and seven spectral curves of mineral and rock specimens which were obtained from study areas.

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ESTIMATION OF VULNERABLE AREA IN KANGWONDO USING 2-PASS DINSAR TECHNIQUE

  • Jung, Jae-Hoon;Sohn, Hong-Gyoo;Yun, Kong-Hyun
    • Proceedings of the KSRS Conference
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    • 2007.10a
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    • pp.445-448
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    • 2007
  • Korea Peninsula is exposed to landslide problems because large regions of Korea are composed of mountain. As a result, we have a great loss of life and property every year, such as road, bridge, and building. However, conventional survey has many restrictions of time and man power. In recent days, instead of field surveying, remote sensing has our attention for detecting damaged place. Synthetic Aperture Radar (SAR) provides the all-weather capability and complements information available. And through the 2-pass DInSAR technique, we can measure even very small displacement effect. In this study, we generated six interferograms of Kangwondo between 1992 and 1998, and estimated the vulnerable place for landslide.

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