• Journal of Environmental Science International
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• v.15 no.4
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• pp.373-378
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• 2006

The western coast of South Korea is famous for its large and broad tidal lands. Nevertheless, land reclamation, which has been conducted on a large scale, such as Sihwa embankment construction project has accelerated coastal environmental changes in the embankment inland. For monitoring of environmental change, vegetation change detecting of the embankment inland were carried out and field survey data compared with Landsat TM, ETM+, IKONOS, and EOC satellite remotely sensed data. In order to utilize multi-temporal remotely sensed images effectively, all data set with pixel size were analyzed by same geometric correction method. To detect the tidal land vegetation change, the spectral characteristics and spatial resolution of Landsat TM and ETM+ images were analyzed by SMA(spectral mixture analysis). We obtained the 78.96% classification accuracy and Kappa index 0.2376 using March 2000 Landsat data. The SMA(spectral mixture analysis) results were considered with comparing of vegetation seasonal change detection method.

• Journal of the Optical Society of Korea
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• v.20 no.1
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• pp.88-93
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• 2016

Recently laser speckle contrast (LSC) imaging has become a widely used optical method for in vivo assessment of blood flow in the animal brain. LSC imaging is useful for monitoring brain hemodynamics with relatively high spatio-temporal resolution. A speckle contrast imaging system has been implemented with electrical sensory stimulation apparatus. LSC imaging is combined with optical intrinsic signal imaging in order to measure changes in cerebral blood flow as well as neural activity in response to electrical sensory stimulation applied to the hindlimb region of the mouse brain. We found that blood flow and oxygen consumption are correlated and both sides of hindlimb activation regions are symmetrically located. This apparatus could be used to monitor spatial or temporal responses of cerebral blood flow in animal disease models such as ischemic stroke or cortical spreading depression.

• Journal of the Institute of Convergence Signal Processing
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• v.6 no.3
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• pp.120-126
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• 2005

This paper presents the 3D wavelet based video compression system using quad-tree algorithm. The 3D wavelet based video compression system removes the temporal correlation of the input sequences using the motion compensation filter and decomposes the spatio-temporal subband using the spatial wavelet transform. The proposed system allocates the higher bit rate to the low frequency image of the 3D wavelet sequences and improves the 0.64dB PSNR performance of the reconstructed image in comparison with that of H.263. In addition to the limitation on the propagation of the motion compensation error by the 3D wavelet transform, the proposed system progressively transmits the input sequence according to the resolution and rate scalability.

• Journal of the Korean Institute of Intelligent Systems
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• v.15 no.7
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• pp.852-857
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• 2005

This paper discusses a human body extraction method for intelligent robot system. The intelligent robot system requires more robust silhouette extraction method because it has internal vibration and low resolution. The new hybrid silhouette extraction method is proposed to overcome this constrained environment. The temporal and gradient information is combined as hybrid silhouette. The motion region model is used to adjust combining parameters in hybrid silhouette. Finally, the experimental results show the superiority of the proposed method.

• Korean Journal of Remote Sensing
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• v.28 no.6
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• pp.597-609
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• 2012

Leaf area index (LAI) is important in explaining the ability of the crop to intercept solar energy for biomass production and in understanding the impact of crop management practices. This paper describes a procedure for estimating LAI as a function of image-derived vegetation indices from temporal series of IKONOS, Landsat TM, and MODIS satellite images using empirical models and demonstrates its use with data collected at Missouri field sites. LAI data were obtained several times during the 2002 growing season at monitoring sites established in two central Missouri experimental fields, one planted to soybean (Glycine max L.) and the other planted to corn (Zea mays L.). Satellite images at varying spatial and spectral resolutions were acquired and the data were extracted to calculate normalized difference vegetation index (NDVI) after geometric and atmospheric correction. Linear, exponential, and expolinear models were developed to relate temporal NDVI to measured LAI data. Models using IKONOS NDVI estimated LAI of both soybean and corn better than those using Landsat TM or MODIS NDVI. Expolinear models provided more accurate results than linear or exponential models.

• Korean Journal of Soil Science and Fertilizer
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• v.46 no.4
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• pp.237-244
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• 2013

Radar remote sensing is appropriate for monitoring rice because the areas where this crop is cultivated are often cloudy and rainy. Especially, Synthetic Aperture Radar (SAR) can acquire remote sensing information with a high temporal resolution in tropical and subtropical regions due to its all-weather capability. This paper analyzes the relationships between backscattering coefficients of rice measured by RADARSAT-2 SAR and growth parameters during a rice growth period. We examined the temporal variations of backscattering coefficients with full polarization. Backscattering coefficients for all polarizations increased until Day Of Year (DOY 222) and then decreased along with Leaf Area Index (LAI), fresh weight, and Vegetation Water Content (VWC). Vertical transmit and Vertical receive polarization (VV)-polarization backscattering coefficients were higher than Horizontal transmit and Horizontal receive polarization (HH)-polarization backscattering coefficients in early rice growth stage and HH-polarization backscattering coefficients were higher than VV-polarization backscattering coefficients after effective tillering stage (DOY 186). Correlation analysis between backscattering coefficients and rice growth parameters revealed that HH-polarization was highly correlated with LAI, fresh weight, and VWC. Based on the observed relationships between backscattering coefficients and variables of cultivation, prediction equations were developed using the HH-polarization backscattering coefficients.

• The Bulletin of The Korean Astronomical Society
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• v.36 no.2
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• pp.88.1-88.1
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• 2011

Shocks are thought to be important in the dynamics and heating of the solar chromosphere. The observational determination of shock parameters, however, has been hardly done because of the difficulty of observation at a high spatial, temporal and spectral resolution, and the lack of an effective method of inferring physical parameters from spectral data. Our inversion of the spectral data of the $H{\alpha}$ and Ca II 854.2 nm lines simultaneously taken from an intranetwork area, produced temporal profiles of temperature as well as line-of-sight velocities, from which we infer that three-minute chromospheric oscillations prevailing in the upper chromosphere are in fact trains of strong shocks with a strength of about two and a propagation speed of 20 km s-1 that carry a mechanical energy flux of 500 W m-2 upward. Our result supports the notion that shocks dominate the heating of the upper chromosphere, and probably the corona as well, at least in intranetwork regions of the quiet sun.

• Journal of the Korean Society of Marine Environment & Safety
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• v.3 no.2
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• pp.23-31
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• 1997

The results of high speed photography, acoustic emission detection and plasma UV radiation intensity measurement during CO2 laser welding of stainless steel 304 are presented. Video images with high spatial and temporal resolution allowed to observe the melt dynamics and keyhole evolution. The existence of a high speed melt flow which originated from the part of weld pool and flowed along the sides wall of keyhole was confirmed by the slag motion on the weld pool. the characteristic frequencies of flow instability and keyhole fluctuations at different welding speed were measured and compared with the results of Fourier analyses of temporal acoustic emission (AE) and light emission (LE) spectra. The experimental results were compared with the newly developed numerical model of keyhole dynamics. (The model is based on the assumption that the propagation of front part of keyhole into material is due to the melt ejection driven by laser induced surface evaporation.) The calculations predict that a high speed melt flow is induced at the front part of keyhole when the sample travel speed exceeds several 10mm/s. The numerical analysis also shows the hump formation on the front keyhole wall surface. Experimentally observed melt behavior and transformation of the AE and LE spectra with variation of welding speed are qualitatively in good agreement with the model predictions.

• Journal of the Institute of Electronics Engineers of Korea SP
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• v.46 no.5
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• pp.25-31
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• 2009

The recently developed sampling theory, "compressed sensing" is gathering huge interest in MR reconstruction area because of its feasibility of high spatio-temporal resolution of dynamic MRI which has been limited in conventional methods based on Nyquist sampling theory. Since dynamic MRI usually has high redundant information along temporal direction, this can be very sparsely represented in most of cases. Therefore, compressed sensing that exploits the sparsity of unknown images can be effectively applied in most of dynamic MRI. This review article briefly introduces currently proposed compressed sensing based dynamic MR imaging algorithms and other methods exploiting sparsity. By comparing them with conventional methods, you may have insight how the compressed sensing based methods can impact nearly every area of clinical dynamic MRI.

• Korean Journal of Remote Sensing
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• v.24 no.1
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• pp.35-43
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• 2008

The purpose of this study is to evaluate the hydrological impact due to temporal land cover change by gradual urbanization of upstream watershed of Pyeongtaek gauging station of Anseong-cheon. WMS HEC-1 was adopted, and OEM with 200 m resolution and hydrologic soil group from 1:50,000 scale soil map were prepared. Land covers of 1986, 1990, 1994 and 1999 Landsat TM images were classified by maximum likelihood method. The watershed showed a trend that forest & paddy areas decreased and urban/residential area gradually increased during the four selected years. The model was calibrated at 2 locations (Pyeonglaek and Gongdo) by comparing observed with simulated discharge results for 5 summer storm events from 1998 to 2001. The watershed average CN values varied from 61.7 to 62.3 for the 4 selected years. To identify the impact of streamflow by temporal area change of a target land use, a simple evaluation method that the CN values of areas except the target land use are unified as one representative CN value was suggested. By applying the method, watershed average CN value was affected in the order of paddy, forest and urban/residential, respectively.