• The Journal of the Korea Contents Association
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• 제11권5호
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• pp.41-49
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• 2011

Recently, the infrastructure of stereoscopy is growing fast. Though, the stereoscopy producing capacity is insufficient to meet the demand of the market. Because, at the moment most people who produce the stereoscopy are skilled for the two-dimensional images. So the characteristics of the human stereopsis and stereoscopic cameras are not well considered, it occurs many problems to the viewer. According to this, we studied about the optical axis distance adjustment of stereoscopic camera considering size perception in human stereopsis. First, we measured the area of the object in the image which depends on the optical axis distance. Second, based on the output of first experiment, we conducted a survey and figured out that if we keep the optical axis distance between 3.9cm to 130cm, it wouldn't occur any size perception and will be possible to produce high quality stereoscopy.

• Journal of the Korea Institute of Information and Communication Engineering
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• 제19권2호
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• pp.486-492
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• 2015

Radiation source imaging system is essential for protecting of radiation leakage accidents and minimizing damages from the radioactive materials, and is expected to play an important role in the nuclear plant decommissioning area. In this study, the stereoscopic camera principle was applied to develop a new radiation imaging device technology that can extract the radiation three-dimensional position information. This radiation three-dimensional imaging device (K3-RIS) was designed as a compact structure consisting of a radiation sensor, a CCD camera, and a pan-tilt only. It features the acquisition of stereoscopic radiation images by position change control, high-resolution detection by continuous scan mode control, and stereoscopic image signal processing. The performance analysis test of K3-RIS was conducted for a gamma-ray source(Cs-137) in radiation calibration facility. The test result showed that a performance error with less than 3% regardless of distances of the objects.

• 한국가시화정보학회:학술대회논문집
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• 한국가시화정보학회 2002년도 추계학술대회 논문집
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• pp.23-26
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• 2002

The phase-averaged velocity fields of 3 dimensional turbulent wake behind a marine propeller measured by 2D PIV and stereoscopic PIV(SPIV) were compared directly. In-plane velocity fields obtained from the consecutive particle images captured by one camera in 2D PIV have perspective errors due to out-of-plane motion. However, the perspective errors can be removed by measuring three component velocity fields using SPIV method with two cameras. It is also necessary to measure three components velocity fields for the investigation of complicated near-wake behind the propeller for the suitable propeller design. 400 instantaneous velocity fields were measured for each of four different blade phases of $0^{\circ},\;18^{\circ},\;36^{\circ}C\;and\;54^{\circ}$. They were ensemble averaged to investigate the spatial evolution of the propeller wake in the downstream region. The phase-averaged velocity fields show the viscous wake developed along the blade surfaces and tip vortices were formed periodically. The perspective errors caused by the out-of-plane motion was estimated by the comparison of 2D PIV and SPIV results. The difference in the axial mean velocity fields measured by both techniques are nearly proportional to the mean out-of-plane velocity component which has large values in the regions of the tip and trailing vortices. The axial turbulence intensity measured by 2D PIV was overestimated since the out-of-plane velocity fluctuations influence the in-plane velocity vectors and increase the in-plane turbulence intensities.

• The Journal of Korean Institute of Communications and Information Sciences
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• 제38C권10호
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• pp.920-927
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• 2013

Chroma key technique which composes images by separating an object from its background in specific color has restrictions on color and space. Especially, unlike general chroma key technique, image composition for stereo 3D display requires natural image composition method in 3D space. The thesis attempted to compose images in 3D space using depth keying method which uses high resolution depth information. High resolution depth map was obtained through camera calibration between the DSLR and Kinect sensor. 3D mesh model was created by the high resolution depth information and mapped with RGB color value. Object was converted into point cloud type in 3D space after separating it from its background according to depth information. The image in which 3D virtual background and object are composed obtained and played stereo 3D images using a virtual camera.

• Journal of the Korea Institute of Information and Communication Engineering
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• 제10권10호
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• pp.1767-1772
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• 2006

Computer-generated integral imaging system is an auto-stereoscopic display system that users can see and feel the stereoscopic images when they see the pre-rendered elemental images through a lens array. The process of constructing elemental images using computer graphics is called image mapping. Viewpoint vector rendering (VVR) method is one of the image mapping algorithm specially designed for real-time graphics applications, which would not be affected by the size of the rendered objects or the number of elemental lenses used in the integral imaging system. This paper describes a new VVR framework which improved its rendering performance considerably. It also compares the previous VVR implementation with the new VVR work utilizing GPU and shows that newer implementation shows pretty big improvements over the old method.

• The Journal of the Korea Contents Association
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• 제16권1호
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• pp.515-520
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• 2016

Volumetric image system has many applications recently in education, 3D movie, medical images but these applications have several problems that need to be overcome. Volumetric display may process a amount of visual data and design the high efficient vision system for realtime display. In case of stereo system for volumetric display motion vectors, disparity vectors from the stereoscopic sequences and residual images with the reference images has been transmitted, and the stereoscopic sequences have been reconstructed at the receiver for volumetric display. So central issue for the design of efficient volumetric image system lies in selecting an appropriate stereo matching and robust vision system. In this paper, we proposed high efficient vision system, which design vision stage with rotating and moving horizontally, and match the successive stereo image efficiently. In experimental results with volumetric image system, the proposed method represents high efficiency with minimizing error and low computational load for volumetric display.

• Journal of the Korea Institute of Information and Communication Engineering
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• 제18권3호
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• pp.551-561
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• 2014

Since the depth and texture images have been widely used for generating 3-dimensional stereoscopic image, the security of them have been focused. In this paper, we propose a new watermarking technique for copyright of stereo and multiview images which is generated in an arbitrary viewpoint by depth and texture image. After the mark space is selected for preserving watermark through DIBR (depth-image-based rendering) process which uses 3D warping, the texture image is transformed to the frequency coefficient using 2D DCT (discrete cosine transform). Some parts of them are quantized, which is the corresponding process to watermarking. The embedded watermark is not conformed by eyes, so we identified the invisibility of the proposed method. In case of appling attacks of general image process, we also identified the robustness of it.

• Proceedings of the Korean Society of Broadcast Engineers Conference
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• 한국방송공학회 2010년도 추계학술대회
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• pp.14-17
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• 2010

Following the proliferation of three-dimensional video contents and displays, many terrestrial broadcasting companies prepare for starting stereoscopic 3DTV service. In terrestrial stereoscopic broadcast, it is a difficult task to code and transmit two video sequences while sustaining as high quality as 2DTV broadcast attains due to the limited bandwidth defined by the existing digital TV standards such as ATSC. Thus, a terrestrial 3DTV broadcasting system with heterogeneous video coding systems is considered for terrestrial 3DTV broadcast where the left image and right images are based on MPEG-2 and H.264/AVC, respectively, in order to achieve both high quality broadcasting service and compatibility for the existing 2DTV viewers. Without significant change in the current terrestrial broadcasting systems, we propose a joint rate control scheme for stereoscopic 3DTV service. The proposed joint rate control scheme applies to the MPEG-2 encoder a quadratic rate-quantization model which is adopted in the H.264/AVC. Then the controller is designed for the sum of two bit streams to meet the bandwidth requirement of broadcasting standards while the sum of image distortions is minimized by adjusting quantization parameter computed from the proposed optimization scheme. Besides, we also consider a condition on quality difference between the left and right images in the optimization. Experimental results demonstrate that the proposed bit rate control scheme outperforms the rate control method where each video coding standard uses its own bit rate control algorithm in terms of minimizing the mean image distortion as well as the mean value and the variation of absolute image quality differences.

• Journal of Broadcast Engineering
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• 제19권2호
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• pp.148-157
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• 2014

Various techniques have been developed for efficient compression of stereoscopic 3D videos. Mixed-resolution based approach is one representative bit-rate saving method based on the characteristics of human visual system that the mixed-resolution stereoscopic videos are perceived close to the higher resolution. However, when the difference between the left and right image resolutions is bigger than a certain threshold level, it causes the perceived quality degradation of the 3D images. Subsequently, several researches tried to find the correlation between the difference in resolution and the level of the perceived quality degradation, but they conducted the experiments just considering the difference in resolution without considering the viewing distances, so thereby different results were retrieved from test to test. In this work, we calculated the optimal viewing distance based on the human visual system, and conducted the subjective tests with the calculated viewing distance. With the results, we demonstrate that the fixed and mobile hybrid 3DTV, which is based on mixed-resolution stereoscopic images, can provide the high quality 3D services.

• Journal of Broadcast Engineering
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• 제13권4호
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• pp.427-439
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• 2008

This paper proposes a novel method to convert monoscopic soccer videos to stereoscopic videos. Through the soccer video analysis process, we detect shot boundaries and classify soccer frames into long shot or non-long shot. In the long shot case, the depth mapis generated relying on the size of the extracted ground region. For the non-long shot case, the shot is further partitioned into three types by considering the number of ground blocks and skin blocks which is obtained by a simple skin-color detection method. Then three different depth assignment methods are applied to each non-long shot types: 1) Depth estimation by object region extraction, 2) Foreground estimation by using the skin block and depth value computation by Gaussian function, and 3)the depth map generation for shots not containing the skin blocks. This depth assignment is followed by stereoscopic image generation. Subjective evaluation comparing generated depth maps and corresponding stereoscopic images indicate that the proposed algorithm can yield the sense of depth from a single view images.