• Korean Journal of Optics and Photonics
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• v.19 no.2
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• pp.95-102
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• 2008

An advantage of parallax barrier displays is that they can also display 2D and 3D contents and can be automatically switched between the two types. But, as the viewer changes position, different views of the scene will be directed by the barrier to the visual system. Moving horizontally beyond a certain point will produce "image flipping" of the different views of the scene. These limitations make unavoidable the use of another autostereoscopic display solutions like eye tracking or increasing the number of views. In this paper, a method of the moving parallax barrier design is introduced to supplement a disadvantage of the fixed parallax barrier that provides observation at specific locations. For making the moving parallax barrier, the cross connector with 640 lines FPC is designed. A commercially available web camera is utilized to implement eye-tracking system and shows the experimental result.

• The Journal of the Korea Contents Association
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• v.18 no.11
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• pp.447-454
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• 2018

This paper proposes a depth image generation algorithm of stereo images using a deep learning model composed of a CNN (convolutional neural network). The proposed algorithm consists of a feature extraction unit which extracts the main features of each parallax image and a depth learning unit which learns the parallax information using extracted features. First, the feature extraction unit extracts a feature map for each parallax image through the Xception module and the ASPP(Atrous spatial pyramid pooling) module, which are composed of 2D CNN layers. Then, the feature map for each parallax is accumulated in 3D form according to the time difference and the depth image is estimated after passing through the depth learning unit for learning the depth estimation weight through 3D CNN. The proposed algorithm estimates the depth of object region more accurately than other algorithms.

• Journal of Broadcast Engineering
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• v.11 no.4 s.33
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• pp.495-506
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• 2006

In this paper, we propose a self-calibration of a multi-camera system using factorization techniques for realistic contents generation. The traditional self-calibration algorithms for multi-camera systems have been focused on stereo(-rig) camera systems or multiple camera systems with a fixed configuration. Thus, it is required to exploit them in 3D reconstruction with a mobile multi-camera system and another general applications. For those reasons, we suggest the robust algorithm for general structured multi-camera systems including the algorithm for a plane-structured multi-camera system. In our paper, we explain the theoretical background and practical usages based on a projective factorization and the proposed affine factorization. We show experimental results with simulated data and real images as well. The proposed algorithm can be used for a 3D reconstruction and a mobile Augmented Reality.

• Journal of Broadcast Engineering
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• v.18 no.1
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• pp.31-42
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• 2013

This paper proposes a photogrammetric rectification method based on Bayesian approach as a method that eliminates vertical parallax between stereo images to minimize visual fatigue of 3D contents. The image rectification consists of two phases; geometry estimation and epipolar transformation. For geometry estimation, coplanarity-based relative orientation algorithm was used in this paper. To ensure robustness for mismatch and localization error occurred by automation of tie point extraction, Bayesian approach was applied by introducing several prior constraints. As epipolar transformation perspective transformation was used based on condition of collinearity to minimize distortion of result images and modification for input images. Other algorithms were compared to evaluate performance. For geometry estimation, traditional relative orientation algorithm, 8-points algorithm and stereo calibration algorithm were employed. For epipolar transformation, Hartley algorithm and Bouguet algorithm were employed. The evaluation results showed that the proposed algorithm produced results with high accuracy, robustness about error sources and minimum image modification.

• Journal of the Institute of Electronics and Information Engineers
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• v.54 no.1
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• pp.165-170
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• 2017

Web 3D technology can be used to simulate the experiments of scientific, medical, engineering and multimedia visualization. On the web environment, 3D virtual reality can be accessed well without strictly on operating system, location and time. Virtual Reality (VR) is used to depict a three-dimensional, computer generated realistic images, sound and other sensations to replicated a real environment or an imaginary setting which can be explored and interacted with by a person. That person is immersed within virtual environment and is able to manipulate objects or perform a series of action. Virtual environment can be created with X3D which is the ISO standard for defining 3D interactive, web-based 3D content and integrating with multimedia. In this paper, we discuss about X3D VR stereo rendering scene and propose new X3D nodes for the HMD VR (head mounted display virtual reality). The proposed nodes are visualized by the web browser X3DOM of X3D.

• Electronics and Telecommunications Trends
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• v.27 no.6
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• pp.49-56
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• 2012

본고는 3DTV, UHDTV(Ultra High Definition Television)와 같은 실감방송 환경에서 실감 오디오 서비스를 제공하기 위한 초다채널 오디오 기술의 최근 연구 및 개발 동향을 소개한다. 스테레오와 5.1 채널로 대표되는 기존의 오디오 기술은 2차원 평면상에서만 음장을 형성할 수 있다는 표현의 한계를 가지고 있다. 3D 영화의 성공과 UHDTV로 대표되는 초고화질 비디오와 부합하기 위해서는 오디오도 3차원 공간상에서 표현되어야 하며 이를 위해서는 필연적으로 출력채널 수가 증가하여야 한다. 이러한 초다채널 오디오는 22.2 채널과 같은 대용량의 오디오 데이터를 압축하는 기술뿐만 아니라 다양한 오디오 출력 환경에 적응적으로 오디오 콘텐츠를 표현하는 기술에 대한 연구/개발이 필요하다.

• Journal of the Semiconductor & Display Technology
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• v.16 no.2
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• pp.70-74
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• 2017

Given two stereo images of a scene, it is possible to recover a 3D understanding of the scene. This is the primary way that the human visual system estimates depth. This process is useful in applications like robotics, where depth sensors may be expensive but a pair of cameras is relatively cheap. In this work, we combined our interests to implement a graph cut algorithm for stereo correspondence, and performed evaluation against a baseline algorithm using normalized cross correlation across a variety of metrics. Experimental trials revealed that the proposed descriptor exhibited a significant improvement, compared to the other existing methods.

• Convergence Security Journal
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• v.13 no.3
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• pp.9-15
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• 2013

Calculating of matching cost is an important for efficient stereo matching. To investigate the performance of matching process, the concepts of the existing methods are introduced. Also we analyze the performance and merits of them. The simplest matching costs assume constant intensities at matching image locations. We consider matching cost functions which can be distinguished between pixel-based and window-based approaches. The Pixel-based approach includes absolute differences (AD) and sampling-intensitive absolute differences (BT). The window-based approach includes the sum of the absolute differences, the sum of squared differences, the normalized cross-correlation, zero-mean normalized cross-correlation, census transform, and the absolute differences census transform (AD-Census). We evaluate matching cost functions in terms of accuracy and time complexity. In terms of the accuracy, AD-Census method shows the lowest matching error ratio (the best solution). The ZNCC method shows the lowest matching error ratio in non-occlusion and all evaluation part. But it performs high matching error ratio at the discontinuities evaluation part due to blurring effect in the boundary. The pixel-based AD method shows a low complexity in terms of time complexity.

• The Journal of the Acoustical Society of Korea
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• v.28 no.7
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• pp.589-598
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• 2009

As mobile devices become multi-functional, and converge into a single platform, there is a strong need for a codec that is able to provide consistent quality for speech and music content MPEG-D USAC standardization activities started at the 82nd MPEG meeting with a CfP and approved WD3 at the 88th MPEG meeting. MPEG-D USAC is converged technology of AMR-WB+ and HE-AAC V2. Specifically, USAC utilizes three core codecs (AAC ACELP and TCX) for low frequency regions, SBR for high frequency regions and the MPEG Surround tool for stereo information. USAC can provide consistent sound quality for both speech and music content and can be applied to various applications such as multi-media download to mobile device Digital radio Mobile TV and audio books.

• Journal of the Korea Computer Graphics Society
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• v.22 no.3
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• pp.11-20
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• 2016

This paper introduces an effective method for generating 3D stereoscopic images that gives immersive 3D experiences to viewers using mobile-based binocular HMDs. Most of previous AR systems with monocular cameras have a common limitation that the same real-world images are provided to the viewer's eyes without parallax. In this paper, based on the assumption that viewers focus on the marker in the scenario of marker based AR, we recovery the binocular disparity about a camera image and a virtual object using the pose information of the marker. The basic idea is to generate the binocular disparity for real-world images and a virtual object, where the images are placed on the 2D plane in 3D defined by the pose information of the marker. For non-marker areas in the images, we apply blur effects to reduce the visual discomfort by decreasing their sharpness. Our user studies show that the proposed method for 3D stereoscopic image provides high depth feeling to viewers compared to the previous binocular AR systems. The results show that our system provides high depth feelings, high sense of reality, and visual comfort, compared to the previous binocular AR systems.