• Korean Journal of Remote Sensing
• /
• v.2 no.2
• /
• pp.117-131
• /
• 1986

The purpose of this study was to develop techniques acquiring hydrologic parameters that affect runoff conditions from Landsat imagery. Runoff conditions in a study area were analyzed by employing the U.S. Soil Conservation Service(SCS) Method. SCS runoff curve numbers(CN) were estimated by the computer analysis of Landsat imagery and digiral terrain model(DTM) data. The SCS Method requires land use/cover and soil conditions of the area as input parameters. A land use/cover map of 5 hydrological classes was produced from the Landsat multi-spectral scannerr imagery. Slope-gradient and contour and contour maps were also made using the DTM topographic data. Inundation areas depending on reservoir levels were able to be mapped on the Landsat scene by combining the contour data.

• Proceedings of the KSRS Conference
• /
• 2007.10a
• /
• pp.18-21
• /
• 2007

Digital image watermarking is a technology used in copyrighting of digital images by embedding unremovable informations. In this paper, a pixel-domain look-up-table-based watermarking algorithm is presented. With this methodology, the watermark was embedded in the host image, but we did not observe any distortion at certain specific region of interest. This means the proposed method is preferred in case of satellite images. Then, the image manipulation tool which is called 'StirMark' will be used to perform many kinds of attacks such as rotation, scaling, filtering and compression on the watermarked image. Finally, the effectiveness of a watermarking technique in terms of 'robustness' and 'data integrity' criteria will be measured by calculating PSNR of watermark and watermarked image.

• Journal of the Korean Society for Precision Engineering
• /
• v.16 no.8
• /
• pp.16-22
• /
• 1999

In this paper, an efficient algorithm for estimating real edge locations to subpixel values is described. Digital images are acquired by projection into image plane and sampling process. However, most of real edge locations are lost in this process, which causes low measurement accuracy. For accurate measurement, we propose an algorithm which estimates the real boundary between two adjacent pixels in digital imagery, with subpixel accuracy. We first define 1D edge operator based on the moment invariant. To extend it to 2D data, the edge orientation of each pixel is estimated by the LSE(Least Squares Error)line/circle fitting of a set of pixels around edge boundary. Then, using the pixels along the line perpendicular to the estimated edge orientation the real boundary is calculated with subpixel accuracy. Experimental results using real images show that the proposed method is robust in local noise, while maintaining low measurement error.

• Journal of the Korean Society of Surveying, Geodesy, Photogrammetry and Cartography
• /
• v.14 no.2
• /
• pp.189-197
• /
• 1996

Digital Elevation Model, Ortho-image, and 3-D positional data of terrain features are indispensable elements for producing 3-D image information. In this research, digital pbotogrammetric studies were conducted to measure the 3-D positional data on high performance computer systems in order to replace analytical stereo-plotter-oriented tasks with those of digital workstations. Especially, technical approaches to measure these data on stereo workstation were developed and then the results were applied on SPOT satellite images. As the result of this study, the possibilities of the proposed technologies were tested and proved based on the ap-plication of the digital photogrammetric processes to extract 3-D ground coordinates of terrain features from digital satellite imagery.

• Journal of Digital Convergence
• /
• v.11 no.8
• /
• pp.235-242
• /
• 2013

This study aimed to evaluate the effectiveness of imagery training on upper limb function and activities of daily living in subacute stroke patients. This study included 16 voluntary participants with subacute stroke. Subjects were randomly assigned to either experimental or control group, with 8 in each group. Imagery training group performed imagery training during 30 minutes and then task-oriented training 30 minutes a day, 5 times a week for 4 weeks. Control group performed task-oriented training during 30 minutes during a day, 5 times a week for 4 weeks. Assessments were made using the Wolf Motor Function Test (WMFT) and Fugl-Meyer motor function assessment (FMA) to evaluate the changes of upper function. And modified Barthel Index (MBI) was measured to evaluate the activities of daily living. The results showed that imagery training group was more significant increase than control group in WMFT, FMA, and MBI (p<.05). Small to huge effect sizes of 1.59, 2.02, 0.37 were observed for WMFT, FMA, and MBI, respectively. This study indicated that imagery training may be helpful in improving the upper limb function and activities of daily living for subacute stroke patients, and support the clinical feasibility of the imagery training.

• The Journal of the Korea Contents Association
• /
• v.7 no.3
• /
• pp.168-175
• /
• 2007

The flood caused landslide disaster each year because of climate change. And the change of topography from an earthquake makes topographical analysis impossible. This paper performed an investigation about a utilization methods and generation DEM(Digital Elevation Model) after digital aerial photographs quickly when the topographical change happens. Stereo imagery that was collected through digital aerial photographs made a generation of DEM possible. A standard deviation of generated DEM is 0.864m which is somewhat high but shows the real topography. As a result, it should be possible to generate DEM by using aerial photographs in case of the change of topography.

• Proceedings of the KSRS Conference
• /
• 2002.10a
• /
• pp.775-779
• /
• 2002

Currently, high-resolution satellite imagery such as KOMPSAT and IKONOS has been tentatively utilized to various types of urban engineering problems such as transportation planning, site planning, and utility management. This approach aims at software development and followed applications of remotely sensed imagery to transportation geographic analysis. At first, GDPA (Gradient Direction Profile Algorithm) and main modules in it are overviewed, and newly implemented results under MS visual programming environment are presented with main user interface, input imagery processing, and internal processing steps. Using this software, road network are automatically generated. Furthermore, this road network is used to transportation geographic analysis such as gamma index and road pattern estimation. While, this result, being produced to do-facto format of ESRI-shapefile, is used to several types of road layers to urban/transportation planning problems. In this study, road network using KOMPSAT EOC imagery and IKONOS imagery are directly compared to multiple road layers with NGI digital map with geo-coordinates, as ground truth; furthermore, accuracy evaluation is also carried out through method of computation of commission and omission error at some target area. Conclusively, the results processed in this study is thought to be one of useful cases for further researches and local government application regarding transportation geographic analysis using remotely sensed data sets.

• Proceedings of the Korea Water Resources Association Conference
• /
• 2018.05a
• /
• pp.30-30
• /
• 2018

Research on mapping levees is an important task for assessing levee stability. The drone imagery acquired in river basins is useful for generating real-time levee maps. This research proposes a robust methodology for mapping levees in river basins using the drone imagery. In the first step, the multiple imagery taken in the test bed was acquired by the drone. Then, the orthorectified image and DEM (Digital Elevation Model) were generated by the photogrammetry and image processing process. Finally, the significant features on levee surfaces such as levee tops, levee lines, levee slopes, eroded areas were detected from the generated DEM and orthorectified image by manual labors and automatic methods. In future research, the automatic procedure for identifying the significant levee features from the drone imagery would be proposed.

• Proceedings of the Korean Society of Surveying, Geodesy, Photogrammetry, and Cartography Conference
• /
• 2003.04a
• /
• pp.479-484
• /
• 2003

The renewal of digital map takes much time and the manual process. LiDAR data allows reduction of time, automatic manner, and acquisition of the precise position. So it is used to renew the digital map of 1:5,000 scale. From the accuracy test results using aerial imagery and digitizing, renewal of digital map are feasible in automatic manner to some extent.

• Journal of the Korea Institute of Information and Communication Engineering
• /
• v.10 no.3
• /
• pp.593-598
• /
• 2006

High-resolution satellite imagery has many benefits, compared to aerial photo in the wide area as well as multi-spectral character. So, it can be used well for constructing GIS data when making digital map. This study analysed the possibilities that road information derived automatically from IKONOS can be used for making ITS system or updating digital map of the urban areas where change frequently and producing satellite image map. In this study, Sobel was applied for road edge dectection after low pass filtering. As the results, it's possible for low pass filtering and high pass filtering to be used as the basic data for ITS construction when extracting edge roads and constructs according to the characteristic of high-resolution satellite imagery.