• Korean Journal of Remote Sensing
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• v.32 no.1
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• pp.39-48
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• 2016

Yangon Mega City is densely populated and most urbanization area of Myanmar. Rapid urbanization is the main causes of Land Use and Land Cover (LULC) change and they impact on Land Surface Temperature (LST). The objectives of this study were to investigate on the LST with respect to LULC of Yangon Mega City. For this research, Landsat satellite images of 1996, 2006 and 2014 of Yangon Area were used. Supervised classification with the region of interest and calculated change detection. Ground check points used 348 points for accuracy assessment. The overall accuracy indicated 89.94 percent. The result of this paper, the vegetation area decreased from $1061.08sq\;km^2$ (24.5%) in 1996 to $483.53sq\;km^2$ (11.2%) in 2014 and built up area clearly increased from $485.33sq\;km^2$ (11.2%) in 1996 to $1435.72sq\;km^2$ (33.1%) in 2014. Although the land surface temperature was higher in built up area and bare land, lower value in cultivated land, vegetation and water area. The results of the image processing pointed out that land surface temperature increased from $23^{\circ}C$, $26^{\circ}C$ and $27^{\circ}C$ to $36^{\circ}C$, $42^{\circ}C$ and $43.3^{\circ}C$ for three periods. The findings of this paper revealed a notable changes of land use and land cover and land surface temperature for the future heat management of sustainable urban planning for Yangon Mega city. The relationship of regression experienced between LULC and LST can be found gradually stronger from 0.8323 in 1996, 0.8929 in 2006 and 0.9424 in 2014 respectively.

• Korean Journal of Remote Sensing
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• v.30 no.5
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• pp.617-625
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• 2014

The Rational Function Model has been used as a replacement sensor model in most commercial photogrammetric systems due to its capability of maintaining the accuracy of the physical sensor models. Although satellite images with rational polynomial coefficients have been used to determine three-dimensional position, it has limitations in the accuracy for large scale topographic mapping. In this study, high resolution stereo satellite images, QuickBird-2, were used to investigate how much the three-dimensional position accuracy was affected by the No. of ground control points, polynomial order, and distribution of GCPs. As the results, we can confirm that these experiments satisfy the accuracy requirements for horizontal and height position of 1:25,000 map scale.

• Korean Journal of Ecology and Environment
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• v.48 no.3
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• pp.188-194
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• 2015

River channel dredging and riparian development have been influenced morphology and quantity of natural river habitat. We compared distribution of riverside land and alluvial island in the Nakdong River with field survey and remote sensing analysis after the 4 Large River Project in South Korea. We digitized geomorphological elements, includes main channel, riverside land, and alluvial island by using georeferenced aerial photos taken in pre-dredging (2008) and post-dredging (2012) periods. Field survey was followed in 2012 for a ground truth of digitized boundaries and identification of newly constructed wetland types such as pond, channel, branch, and riverine type. We found that during the dredging period, riverside land and alluvial island were lost by 20.2% and 72.7%, respectively. Modification rate of riverside land was higher in the section of river kilometer 50~90, 140~180, and 210~270. Alluvial island had higher change rate in the section of river kilometer 50~70, 190~210, and 270~310. Average change rate for the riverside land and alluvial island was $-1.02{\pm}0.14km^2{\cdot}10km^{-1}$ and $-0.05{\pm}0.05km^2{\cdot}10km^{-1}$, respectively. Channel shaped wetlands (72.5%) constituted large portion of newly constructed wetlands.

• Korean Journal of Remote Sensing
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• v.26 no.2
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• pp.143-151
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• 2010

We carried out studies on InSAR techniques for time-series deformation monitoring using multi-temporal SAR. The PSInSAR method using permanent scatterer is much more complicate than the SBAS because it includes many non-linear equation due to the input of wrapped phase. It is conformed the PS algorithm is very sensitive to even PSC selection. On the other hand, the SBAS method using interferogram of small baseline subset is simple but sensitive to the accuracy of unwrapped phase. The SBAS is better method for expecting not significant unwrapping error while PSInSAR is more proper method for expecting local deformation within very limited area. We used 51 ERS-1/2 SAR data during 1992-2000 over Las Vegas, USA for the comparison between PSInSAR and SBAS. Both PSInSAR and SBAS show similar ground deformation value although local deformation seems to be detected in the PSInSAR method only.

• Korean Journal of Remote Sensing
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• v.16 no.1
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• pp.73-86
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• 2000

Commonly-used methods for camera modelling of pushbroom images were implemented and their performances were assessed. The models include Vector Propagation) model, Gugan and Downman(GD)'s model, Orun and Natarajan(ON)'s model, and Direct Linear Transformation(DLT) model The models were tested on a SPOT full-scene over Seoul. The number of ground control points(GCP) used range from 1 to 23. For less than 6 GCPs all other models fail except VP, with VP's accuracy being 2.7 pixels. With mode than 6 GCPs ON shows the best accuracy with 1pixel accuracy while the accuracy of VP is 1.5 pixels. GD fails in most cases due to the correlation among model parameters. The accuracy of DLT does not converge but fluctuates between 1 and 4 pixels subject to GCPs used. VP has an advantage in that its results can be used for the estimation of satellite orbit. Unresolved topics are: to remove errors in GCPs from the aforementioned accuracy value; to improve the performance of VP.

• Korean Journal of Remote Sensing
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• v.13 no.1
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• pp.57-73
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• 1997

This paper is related to the correction of radiometric distortions induced by topographic relief. RADARSAT SAR image data were obtained over the mountainous area near southern part of Seoul. Initially, the SAR data was geometrically corrected and registered to plane rectangular coordinates so that each pixel of the SAR image has known topographic parameters. The topographic parameters (slope and aspect) at each pixel position were calculated from the digital elevation model (DEM) data having a comparable spatial resolution with the SAR data. Local incidence angle between the incoming microwave and the surface normal to terrain slope was selected as a primary geometric factor to analyze and to correct the radiometric distortions. Using digital maps of forest stands, several fields of rather homogeneous forest stands were delineated over the SAR image. Once the effects of local incidence angle on the radar backscatter were defined, the radiometric correction was performed by an empirical fuction that was derived from the relationship between the geometric parameters and mean radar backscatter. The correction effects were examined by ground truth data.

• Korean Journal of Remote Sensing
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• v.24 no.3
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• pp.223-233
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• 2008

In the mid 90's, the U.S. government released images acquired by the first generation of photo reconnaissance satellite missions between 1960 and 1972. The Declassified Intelligent Satellite Photographs (DISP) from the Corona mission are of high quality with an astounding ground resolution of about 2 m. The KH-4A panoramic camera system employed a scan angle of $70^{\circ}$ that produces film strips with a dimension of $55\;mm\;{\times}\;757\;mm$. Since GPS/INS did not exist at the time of data acquisition, the exterior orientation must be established in the traditional way by using control information and the interior orientation of the camera. Detailed information about the camera is not available, however. For reconstructing points in object space from DISP imagery to an accuracy that is comparable to high resolution (a few meters), a precise camera model is essential. This paper is concerned with the derivation of a rigorous mathematical model for the KH-4A/B panoramic camera. The proposed model is compared with generic sensor models, such as affine transformation and rational functions. The paper concludes with experimental results concerning the precision of reconstructed points in object space. The rigorous mathematical panoramic camera model for the KH-4A camera system is based on extended collinearity equations assuming that the satellite trajectory during one scan is smooth and the attitude remains unchanged. As a result, the collinearity equations express the perspective center as a function of the scan time. With the known satellite velocity this will translate into a shift along-track. Therefore, the exterior orientation contains seven parameters to be estimated. The reconstruction of object points can now be performed with the exterior orientation parameters, either by intersecting bundle rays with a known surface or by using the stereoscopic KH-4A arrangement with fore and aft cameras mounted an angle of $30^{\circ}$.

• Korean Journal of Remote Sensing
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• v.26 no.1
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• pp.9-20
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• 2010

The LIDAR data can be efficiently utilized for automatic reconstruction of 3D models of objects on the terrain and the terrain itself. In this paper, we attempted to generate simulated waveforms of FW (Full-Waveform) LIDAR (LIght Detection And Ranging). We performed the geometric modeling of the sensor and objects, and the radiometric modeling of the waveform intensity. First, we compute the origins and directions of the sub-beams by considering the divergence effects of a laser beam. We then searched for the locations at which the sub-beams intersected with the objects, such as ground, buildings and trees. Finally, we generate the individual waveforms of the reflected sub-beams and the waveform of the entire beam by summing the individual ones. With the experimental results, we confirmed the waveforms were reasonably generated, showing the characteristics of the surfaces the beam interacted with.

• Korean Journal of Remote Sensing
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• v.23 no.4
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• pp.247-256
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• 2007

In this paper we introduced GB-SAR focusing algorithms for image formation and suggested an optimized solution. We compared the characteristics, advantages, and limitations of the Deramp-FFT (DF) algorithm and the Range-Doppler (RD) algorithm in terms of their image formation principles, memory usage and processing time. We found that DF algorithm is efficient in memory and processing time but can not focus the near range. The RD algorithm can focus the entire range but, considering the refinement on the rail length, it has much redundancy in memory and processing time. In conclusion, we optimized the GB-SAR focusing by using the DF algorithm for a far-range case and the RD algorithm for a near-range case separately.

• Korean Journal of Remote Sensing
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• v.22 no.4
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• pp.285-294
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• 2006

A numerical formula that presents relationship between a point of a satellite image and its ground position is called a sensor model. For precise geolocation of satellite images, we need an error-free sensor model. However, the sensor model based on GOES ephemeris data has some error, in particular after Image Motion Compensation (IMC) mechanism has been turned off. To solve this problem, we investigated three sensor models: collinearity model, direct linear transform (DLT) model and orbit-based model. We applied matching between GOES images and global coastline database and used successful results as control points. With control points we improved the initial image geolocation accuracy using the three models. We compared results from three sensor models. As a result, we showed that the orbit-based model is a suitable sensor model for precise geolocation of GOES-9 Images.