• Journal of Korea Multimedia Society
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• v.14 no.10
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• pp.1229-1237
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• 2011

The volume ray-casting method is one of the direct volume rendering methods that produces high-quality images as well as manipulates semi-transparent object. Although the volume ray-casting method produces high-quality image by sampling in the region of interest, its rendering speed is slow since the color acquisition process is complicated for repetitive memory reference and accumulation of sample values. Recently, the GPU-based acceleration techniques are introduced. However, they require pre-processing or additional memory. In this paper, we propose efficient point-primitive based method to overcome complicated computation of GPU ray-casting. It presents semi-transparent objects, however it does not require preprocessing and additional memory. Our method is fast since it generates point-primitives from volume dataset during sampling process and it projects the primitives onto the image plane. Also, our method can easily cope with OTF change because we can add or delete point-primitive in real-time.

• Journal of the Korea Institute of Information and Communication Engineering
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• v.21 no.1
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• pp.215-222
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• 2017

An active synthetic aperture sonar mounted on small UUV is generated various trajectory disturbances in the traveling path by the influence of external underwater environments. That is the phase mismatch occurs in the synthetic aperture processing of the signals reflected from seabed objects and fetches the detection performance decreases. In this paper, we compensated deteriorated images by the active SAS autofocus processing using DPC and analyzed the effects of detection performance when the periodic trajectory disturbances occur in the side direction at a constant velocity and straight movement of UUV. Through simulations, the deteriorated images according to the periodic disturbance magnitudes and period variations in the platform were compensated using difference phases processing of the overlapping displaced phase centers on the adjacent transmitted ping signals, and we conformed the improved performance characteristics of azimuth resolution and detection images at 3dB reference point.

• Journal of Broadcast Engineering
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• v.20 no.5
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• pp.718-727
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• 2015

In this paper, we present a novel segmentation method that can extract new foreground objects from a current frame in real-time. It is performed by detecting differences between the current frame and reference frame taken from a fixed camera. We minimize computing complexity for real-time video processing. First DCT (Discrete Cosine Transform) is utilized to generate rough binary segmentation maps where foreground and background regions are separated. DCT shows better result of texture analysis than previous methods where texture analysis is performed in spatial domain. It is because texture analysis in frequency domain is easier than that in special domain and intensity and texture in DCT are taken into account at the same time. We maximize run-time efficiency of DCT by considering color information to analyze object region prior to DCT process. Last we use Guided filter for natural matting of the generated binary segmentation map. In general, Guided filter can enhance quality of intermediate result by incorporating guidance information. However, it shows some limitations in homogeneous area. Therefore, we present an additional method which can overcome them.

• The Journal of the Institute of Internet, Broadcasting and Communication
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• v.12 no.6
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• pp.199-206
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• 2012

Attempt to use as a marker of natural objects directly in the real world, but there is a way to use the accelerometer of the smartphone, to convert the Frontal-View virtual, because it asks only the pitch of the camera, from the side there is a drawback that can not be converted to images. The proposed algorithm, to obtain the rotation matrix of axis 3 pitch, roll, yaw, we set the reference point of the yaw of the target image. Then, to compensate for the rotation matrix to determine Myon'inji any floor, wall, the ceiling of the target image. Finally, to obtain the homography matrix for obtaining the Frontal-View to account for the difference between the gyro sensor coordinate system and image coordinate system, so we can get the Frontal-View from the captured images through the projection transformation was designed. Was tested to convert Frontal-View the picture was taken in an environment smartphone environment surrounding floor, walls and ceiling in order to evaluate the conversion program Frontal-View has been implemented, in this paper, design and The conversion algorithm implementation, it was confirmed that to convert a regular basis Frontal-View footage taken from multiple angles.

• The Bulletin of The Korean Astronomical Society
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• v.35 no.2
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• pp.84.1-84.1
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• 2010

Globular clusters (GCs) are known to be one of the oldest objects in the Milky Way. Therefore the dynamical informations of GCs are very important to understand the formation and evolution of our Galaxy. Motion of GCs in the halo of Galaxy can be traced by radial velocities of individual stars and proper motions of GCs. Measuring the radial velocities of stars in GCs has been challenging for decades because the brightness of stars (even for the brightest stars) in GCs are too faint (V>14) to measure the radial velocities. The available large telescopes (D>4m) enable us to observe the spectra of stars in the red giant branch of GCs, and it is now more plausible to measure the radial velocities of stars in GCs. On the contrary it is still very difficult to measure the sky-projected two-dimensional motion of GCs in Galaxy even with the large telescopes because the distance to GCs is quite large (~10kpc) compared to the spatial resolution of present-day large ground-based telescopes. Instruments on-board Hubble Space Telescope are ideal to study the proper motion of GCs thanks to their extremely high spatial resolution (~0.05arcsec). We report a study of proper motion of NGC 104, one of the most metal-rich Milky Way GCs, based-on archival images of NGC 104 observed using HST/ACS. Using the stars in Small Magellanic Cloud as reference coordinate, we are able to measure the proper motions of individual stars in NGC 104 with a high precision. We discuss the internal dynamics of stars in NGC 104 by comparing proper motion results based-on shorter (<1yr) and longer (~7yrs) time durations.

• Journal of Korea Game Society
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• v.14 no.6
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• pp.49-58
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• 2014

In particle-based fluid simulation, the yield stress is required for the deformation of the viscoelastic material like gel. von Mises's yield condition has been proposed to implement deformation of viscoelastic objects, but did not express the explosion. Furthermore, von Mises's yield condition is hard to approximate. We propose an ideal yield condition for viscoelastic object that reference from Tresca's yield condition. Unlike conventional particle-based simulation approximate the external power by the deformed length of the object, this paper is approximate the external power by area of the object. We check up that explosion was realistic when a viscoelastic object is compressed under the ideal yield condition.

• Journal of Korea Multimedia Society
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• v.8 no.2
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• pp.164-173
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• 2005

Painterly rendering may bring various results through the parameters that determine the characteristics of brush strokes such as, color, orientation, size, and shape. In this paper, we propose the most adaptive brush stroke generation for source images, using reference data. Our algorithm used Colors formed by actual palette colors from artists. To create the palette, we have referred mostly to colors used in Van Gogh's works and determined the color of brush strokes by transferring it to the most similar one, through comparing colors used in source images and the palette colors. Also, In order to emulate a brush stroke with dynamic properties like Van Gogh styles we have applied a brush stroke orientation that surrounds the edges by referring to the edge orientation of source images. The sizes were determined depending on the different sizes of the objects from wide to narrow brushes. Finally, we applied spline curve shapes to simulate curves and swirls like Van Gogh styles. The brush strokes created in such method, were applied separately according to its segmented images, and composed after rendering.

• Proceedings of the Korean Institute of Information and Commucation Sciences Conference
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• 2008.10a
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• pp.348-353
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• 2008

Despite the increasing popularity of wireless sensor network, indoor positioning using low power IEEE 802.15.4 compliant radio had attracted an interest of many researchers in the last decade. Old fashionable indoor location sensing information has been presented in dull and unpleasant 2D image standard. This paper focused on visualizing high precision 3 dimensional RSSI-based (received signal strength indication) spatial sensing information in an interactive virtual reality on PDA. The developed system operates by capturing and extracting signal strength information at multiple pre-defined reference nodes to provide information in the area of interest, thus updating user's location in 3D indoor virtual map. VRML (Virtual Reality Modeling Language) which specifically developed for 3D objects modeling is utilized to design 3D indoor environment.

• Journal of Broadcast Engineering
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• v.18 no.2
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• pp.159-166
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• 2013

In this paper, we propose a transmission rate compensation method to remove a haze of an image by using edge information of a haze image and image segmentation. With a hazed image, it is difficult not only to recognize objects in the image but also to use an image processing method. One of the famous defogging algorithm named 'Dark Channel Prior'(DCP) is used to predict fog transmission rate using dark area of an image, and eliminates fog from the image. But there is a big possibility to calculate a wrong transmission rate if the area of high RGB values is larger than the area of the reference area. Therefore we eliminate color distortion area to calculate transmission rate by using the propose method, and obtain a natural clean image from a hazed image.

• The Journal of Korean Institute of Communications and Information Sciences
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• v.33 no.9C
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• pp.712-719
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• 2008

Temporal error concealment indicates the algorithm that restores the lost video data using temporal correlation between previous frame and current frame with lost data. It can be categorized into the methods of block-based and pixel-based concealment. The proposed method in this paper is for pixel-based temporal error concealment using affine transform. It outperforms especially when the object or background in lost block has geometric transform which can be modeled using affine transform, that is, rotation, magnification, reduction, etc. Furthermore, in order to maintain good performance even though one or more motion vector represents the motion of different objects, we defines a cost function. According to cost from the cost function, the proposed method adopts affine error concealment adaptively. Simulation results show that the proposed method yields better performance up to 1.9 dB than the method embedded in reference software of H.264/AVC.