• Journal of the Society of Naval Architects of Korea
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• v.58 no.6
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• pp.382-390
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• 2021

The present study suggests the application of a depth camera for wave height field measurement, focusing on the calibration procedure and test setup. Azure Kinect system is used to measure the water surface elevation, with a field of view of 800 mm × 800 mm and repetition rate of 30 Hz. In the optimal optical setup, the spatial resolution of the field of view is 288 × 320 pixels. To detect the water surface by the depth camera, tracer particles that float on the water and reflects infrared is added. The calibration consists of wave height scaling and correction of the barrel distortion. A polynomial regression model of image correction is established using machine learning. The measurement results by the depth camera are compared with capacitance type wave height gauge measurement, to show good agreement.

• Journal of the Korean Society of Manufacturing Technology Engineers
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• v.21 no.5
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• pp.708-713
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• 2012

The indented geometry for rockwell hardness indenter has been configured by using Confocal Laser Scanning Microscopy (CLSM). For this purpose, the CLSM can be well suited to construct the three-dimensional indented volume from the indented surface by rockwell hardness tester. Furthermore, the height data of HEI(height encoded image) by CLSM must be acquired at first and converted to indented surface later. And the indented surface patterns enable us to predict the indenter shape and volume. This volume can be used to study the rockwell hardness model as a volume parameter. As a result, the technique performed in this study by combining the CLSM with compensation technique is an excellent one to obtain the geometries of indented surfaces over a wide range of surface resolution in a micro scale. And it can be used for micro volume calculation.

• The Korean Journal of Pain
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• v.24 no.4
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• pp.235-238
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• 2011

Vertebral compression fractures result in vertebral height loss and alter sagittal spinal alignment, which in turn can lead to increased morbidity and mortality. Acute osteoporotic vertebral compression fractures are known to increase mobility and instability of the spine. There are limited published data correlating the degree of dynamic mobility and the efficacy of kyphoplasty on vertebral compression fractures. Here we report a 73-year-old female with a severe acute osteoporotic L2 compression fracture who obtained total vertebral height restoration following kyphoplasty, with resolution of back pain.

• Journal of the Korean Institute of Illuminating and Electrical Installation Engineers
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• v.20 no.6
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• pp.26-34
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• 2006

In this paper, We proposed he algorithm for defect extraction and a study of the stereo image modeling o inspect defect for the ball height of BGA(ball grid way) device using 2-dimensional images captured by the BGA device of using the high resolution CCD cameras. This paper propose the package/ball area extraction of BGA device part, the FOV(field of view) calibration part, the top point matching part, and ball height measurement method. Each BGA device propose extraction method by defect, Through the experiment, we verified the result.

• Journal of the Korean Society of Surveying, Geodesy, Photogrammetry and Cartography
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• v.18 no.1
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• pp.59-66
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• 2000

This study describes the precise DTM by image processing method through scanning the positive film of aerial photo using scanner instead of plotter. First, scanned the positive film of aerial photo by drum scanner and flatbed scanner in different resolution, and then compared the height from image processing method using auto correlation method with height which is taken using $50^m{\times}50^m$ grid in 1 :5,000 geographical map. It shows that heights from aerial photo image of high resolution obtained from scanner are comparable to the heights from 1：5,000 geographical map.

• Journal of Korean Society for Geospatial Information Science
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• v.17 no.3
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• pp.71-79
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• 2009

We expanded the 3D building information extraction method using shadow and vertical line from single high resolution image with meta information into the method for single high resolution image without meta information. Our method guesses an azimuth angle and an elevation angle of the sensor and the sun using reference building, selected by user, on an image. For test, we used an IKONOS image and an image extracted from the Google Earth. We calculated the Root Mean Square (RMS) error of heights extracted by our method using the building height extracted from stereo IKONOS image as reference, and the RMS error from the IKONOS image and the Google Earth image was under than 3 m. We also calculated the RMS error of horizontality position by comparison between building position extracted from only the IKONOS image and it from 1:1,000 digital map, and the result was under than 3 m. This test results showed that the height pattern of building models by our method was similar with it by the method using meta information.

• Korean Journal of Optics and Photonics
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• v.19 no.5
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• pp.376-380
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• 2008

This paper presents the Projection Moire method using a line scan camera. The high resolution feature of a line scan camera makes it possible to scan an image quickly, thus enabling a much quicker 3D profile. This method uses a high resolution line scan camera making it possible to scan an image at high speed simultaneously measuring the 3D profile of a large FOV. When using a high resolution scan camera, a full FOV is scanned, thus requiring just one movement of a projection grating. As a result, the number of grating movements is reduced drastically. The end result is a faster and more accurate 3D measurement. Moving the grating too quickly causes vibration in the imaging system, which will normally be required to apply a stitching technique when using an area scan camera. However the technique is not required when using a line scan camera. Compared with the previous techniques, it has the advantages of simple hardware without moving mechanical parts - single exposure for obtaining three-dimensional information. A method using a high resolution line scan camera can be used in mass production to measure the bump height of wafers or the bump height of package substrates.

• Atmosphere
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• v.26 no.4
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• pp.673-686
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• 2016

Understanding limitation of simulation for Planetary Boundary Layer (PBL) height in mesoscale meteorological model is important for accurate meteorological variable and diffusion of air pollution. This study examined the accuracy for simulated PBL heights using two different PBL schemes (MYJ, YSU) in Weather Research and Forecasting (WRF) model during the radiosonde observation period. The simulated PBL height were verified using atmospheric sounding data obtained from radiosonde observations that were conducted during 5 months from August to December 2014 over the Gumi weir in Nakdong river. Four Dimensional Data Assimilation (FDDA) using radiosonde observation data were conducted to reduce error of PBL height in WRF model. The assessment result of PBL height showed that RMSE with YSU scheme were lower than that with MYJ scheme in the day and night time, respectively. Especially, the WRF model with YSU scheme produced lower PBL height than with the MYJ scheme during night time. The YSU scheme showed lower RMSE than the MYJ scheme on sunny, cloudy and rainy day, too. The experiment result of FDDA showed that PBL height error were reduced by FDDA and PBL height at the nudging coefficient of $3.0{\times}10^{-1}$ (YSU_FDDA_2) were similar to observation compared to the nudging coefficient of $3.0{\times}10^{-4}$ (YSU_FDDA_1).

• Korean Journal of Remote Sensing
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• v.24 no.4
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• pp.351-358
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• 2008

KOMPSAT-5 will be launched in 2010 carrying a SAR (Synthetic Aperture Radar) system to obtain high resolution images of the earth surface regardless of weather or solar condition. In this paper, the orbits of KOMPSAT-5 and the imaging modes of SAR were analyzed for radargrammetry, and the best image pairs were suggested. We set the pass number from the nearest orbit to a given ground point and selected image pairs for radargrarnmetry, with height sensitivity of parallax higher than 0.5 to achieve enough height resolution and with the value lower than 0.8 to avoid errors from geometric distortion. On the equator, for example, where the distance between two adjacent passes is fixed to 95 km, we solved the orbit geometry and found that the image pairs with the pass numbers of 3-2 and 5-3 are suitable for radargrarnmetry. As the examples with arbitrary latitude, we selected Daejeon and Sejong Antarctic stations and calculated the orbital elements by using STK software. Three image pairs (5-4, 7-5 and 8-5) were found suitable for radargrammetry at Daejeon while 10 pairs (8-6, 9-7, 10-7, 11-8, 12-8, 13-9, 14-9, 15-9, 15-10 and 15-11) at Sejong Antarctic station.

• Journal of the Korean Society of Surveying, Geodesy, Photogrammetry and Cartography
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• v.35 no.6
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• pp.563-572
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• 2017

The purpose of the study is to investigate the effect of flight height, flight speed, exposure time of camera shutter and autofocusing on the visual resolution of the image in order to obtain ultra-high resolution images with a GSD less than 1cm. It is also aimed to evaluate the ease of recognition of various types of aerial targets. For this purpose, we measured the visual resolution using a 7952*5304 pixel 35mm CMOS sensor and a 55mm prime lens at 20m intervals from 20m to 120m above ground. As a result, with automatic focusing, the visual resolution is measured 1.1~1.6 times as the theoretical GSD, and without automatic focusing, 1.5~3.5 times. Next, the camera was shot at 80m above ground at a constant flight speed of 5m/s, while reducing the exposure time by 1/2 from 1/60sec to 1/2000sec. Assuming that blur is allowed within 1 pixel, the visual resolution is 1.3~1.5 times larger than the theoretical GSD when the exposure time is kept within the longest exposure time, and 1.4~3.0 times larger when it is not kept. If the aerial targets are printed on A4 paper and they are shot within 80m above ground, the encoded targets can be recognized automatically by commercial software, and various types of general targets and coded ones can be manually recognized with ease.