• Journal of The Korean Astronomical Society
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• v.29 no.spc1
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• pp.409-410
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• 1996

Speckle Interferometer equipped with an ITT intensified CCD have been used on the NCUO ( National Central University Observatory, Taiwan) 24-inch telescope for studying the orbits of bright binary systems selected from the Yale's Bright Star Catalogue. The high resolution and high sensitivity ITT intensified solid state video camera ( F4577 ) has external gain and gate control functions which will simplify the design of the speckle camera and allow us to do precise speckle photometry. The goal of this project is trying to study the bright binary systems with separations between the average size of seeing disk and the diffraction limit of the 24-inch telescope. Recently some observing data have been reduced and compared with the other teams' results. We are now improving the data reduction technology and trying to use real time observing mode on the monthly routine observation.

• The Bulletin of The Korean Astronomical Society
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• v.42 no.2
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• pp.41.3-42
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• 2017

The mass function of massive high-z clusters is extremely sensitive to the cosmological parameters. However, it is challenging to estimate their accurate masses. The "See Change" HST programme offers a rare opportunity to measure them using weak gravitational lensing. In this talk, we study SPT-CL J0205-5829 (z=1.322) and MOO1014+0038 (z=1.24) discovered in the SPT-SZ survey and MaDCoW Survey, respectively. We perform weak lensing analysis with the Advanced Camera for Surveys (ACS) and Wide Field Camera 3 (WFC3) images by carefully taking into account the instrumental effect. We successfully detect weak lensing signals which produce cluster masses consistent with those from non-lensing methods based on hydrostatic equilibrium.

• The Bulletin of The Korean Astronomical Society
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• v.35 no.2
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• pp.28.2-28.2
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• 2010

We investigate star clusters in the Stephan's Quintet using Wide Field Camera 3 of the Hubble Space Telescope and three filters (F438W, F606W, F814W). Stephan's Quintet located at ~ 85 Mpc, so most star clusters are seen like point source even in HST image. We perform the Point Spread Funtion fitting photometry to find star clusters. Then we have selected 749 star cluster candidates by visual inspection. Usinng simple steallr population models (Bruzual & Charlot, 2003), we estimate ages of these star clusters. Many young star clusters found in tidal features of NGC 7318 and NGC 7319. Also star clusters in the shocked region of NGC7318 have younger age than those in NGC 7319 tidal tail. These result implies interaction which distrupt NGC 7319 first, and collision between NGC 7318 A/B occurred. In contrast, old star clusters are mainly located in NGC 7317 and in the center of other galaxies. Implications of these result will be discussed.

• Journal of Korean Society of Coastal and Ocean Engineers
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• v.18 no.1
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• pp.63-68
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• 2006

Time series of waterline changes during a flood/ebb cycle can be utilized for supplementary data for measuring bottom topography. The waterlines extracted from consecutive images are substituted for depth contours using water level data. The distances between contours are quantified through a rectification image process. This technique is applied to the Keunpoolan beach in the Daeijak Island near Incheon. A camera monitoring technique supported by natural water level changes produces bottom topography with high precision. It is also less time consuming and more economical. The technique also can be utilized effectively to the physical modeling f3r measuring bottom changes in the three dimensional basin.

• Journal of Welding and Joining
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• v.17 no.1
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• pp.71-76
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• 1999

The real-time holographic interferometer with digital high-speed camera is applied to the experimental study of laser induced plasma/plume in pulsed Nd:YAG laser welding. A pulsed Nd:YAG laser with 1.2 kW average power is applied to generate laser induced plume. The recording speed of the high-speed camera is 3,000 f/s. The high speed photographs of weld plume without another visualization method, are compared with the visualization photographs with holographic interferometer. The radiation intensity from the laser induced plume is recorded by the high speed photographs, which fluctuated during laser radiation and disappeared after laser end. The density distribution of the plume is recorded by the holographic visualization method. The experimental results show the process of generation of the laser induced plasma/plume, and give the feasibility of quantitative measurement of laser induced plume in laser welding.

• Journal of the Korean Graphic Arts Communication Society
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• v.26 no.2
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• pp.65-77
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• 2008

The color reproduction of digital still camera does not, in general, match those of the final prints. Because color gamut of these devices is different, it is therefore necessary to take account of a way to match. The way uses the optimized profile to print an image. This paper proposed a way to create the input profile of digital still camera for standardization printing process. The results of proposed way showed that for input profiles equivalent, good results relatively. In this paper, an experiment was done where the illumination sources used as the standard illumination 5200K and illuminated at a $45^{\circ}$ angle in the best illumination efficiently. The white balance was in mode 'custom': aperture F11, exposure time 1/60s, ISO50, focal length 80mm. The images were exported and saved as 16bit RGB tiff(AdobeRGB, sRGB, ProphotoRGB) images. To do the test, the RGB values of the RGB tiff images are processed through the ICC input profile to arrive at processed $CIEL^*a^*b^*$ values. A profiling tool such as ProfileMaker 5.0 and Monacoprofile 4.8 are used to do this. The processed CIEL*a*b* values are compared to the reference CIEL*a*b* values and these two values are used to calculate a ${\Delta}E$.

• Nuclear Medicine and Molecular Imaging
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• v.43 no.4
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• pp.253-258
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• 2009

Bone scintigraphy using $^{99m}$Tc-labeled phosphate agents has long been the standard evaluation method for whole skeletal system. However, recent shortage of $^{99m}$Tc supply and advanced positron emission tomography (PET) technology evoked the attention to surrogate radiopharmaceuticals and imaging modalities for bone. Actually, fluorine-18 ($^{18}$F) was the first bone seeking radiotracer before the introduction of $^{99m}$Tc-labeled agents even though its clinical application failed to become pervasive anymore after the rapid spread of Anger type gamma camera systems in early 1970s. However, rapidly developed PET technology made us refocus on the usefulness of $^{18}$F as a PET tracer. Early study comparing $^{18}$F-Na PET scan and planar bone scintigraphy reported that PET has higher sensitivity and specificity in the diagnosis of metastatic bone lesions than planar bone scan. Subsequent reports comparing between PET and both planar and SPECT bone image also revealed better results of PET scan in similar study groups. Rapid clinical application of PET/CT also accumulated considerable amount of experiences in skeletal evaluation and this modality is known to have better diagnostic power than stand alone PET system as well as bone scan. Furthermore $^{18}$F-Na PET/CT revealed better or at least equal results in detection of primary and metastatic bone lesions compared with CT and MRI. Therefore, it is obvious that $^{18}$F-Na PET/CT has potential to become new imaging modality for practical skeletal evaluation so continuous and careful evaluation of this modality and radiopharmaceutical must be required.

• Proceedings of the Korean Institute of Information and Commucation Sciences Conference
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• 2001.10a
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• pp.375-379
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• 2001

This paper describes a development of remote measurement robot with vision system. The developed robot consists of robot controller and host PC program. The robot and camera can move with 2 degree of freedom by independent remote controlling a user friendly designe joystick. A visual image and command data translated through 900MHz and 447MHz RF controller, respectively. To show the validity of the developed system, operations of the robot in the field area were illustrated.

• Proceedings of the Korean Institute of Information and Commucation Sciences Conference
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• 2002.11a
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• pp.457-461
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• 2002

This paper describes a development of a robot working in hazard environment. The developed robot consists of robot controller with vision system and host PC program. The robot and camera can move with 2 degree of freedom by independent remote controlling a user friendly designed joystick. An environment is recognized by the vision system and ultra sonic sensors. The visual image and command data translated through 900MHz and 447MHz RF controller, respectively. To show the validity of the developed system, operations of the robot in the field area were illustrated.

• Journal of the Optical Society of Korea
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• v.20 no.2
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• pp.283-290
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• 2016

This study presents an 8x four-group inner-focus zoom lens with one-moving group for a compact camera by use of a focus tunable lens (FTL). In the initial design stage, we obtained the powers of lens groups by paraxial design based on thin lens theory, and then set up the zoom system composed of four lens modules. Instead of numerically analytic analysis for the zoom locus, we suggest simple analysis for that using lens modules optimized. After replacing four groups with equivalent thick lens modules, the power of the fourth group, which includes a focus tunable lens, is designed to be changed to fix the image plane at all positions. From this design process, we can realize an 8x four-group zoom system having one moving group by employing a focus tunable lens. The final designed zoom lens has focal lengths of 4 mm to 32 mm and apertures of F/3.5 to F/4.5 at wide and tele positions, respectively.