• Journal of Positioning, Navigation, and Timing
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• v.5 no.2
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• pp.59-66
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• 2016

The International GNSS Service (IGS) provides the IGS-Real Time Service (IGS-RTS) corrections that can be used in stand-alone positioning in real time. In this study, the positioning accuracy before and after the application of the corrections to broadcast ephemeris by applying the IGS-RTS corrections at code pseudo-range based stand-alone positioning was compared with positioning result using precise ephemeris. The analysis result on IGS-RTS corrections showed that orbit error and clock error were 0.05 m and 0.5 ns compared to precise ephemeris and accuracy improved by about 8.5% compared to the broadcast ephemeris-applied result when the IGS-RTS was applied to positioning. Furthermore, regionally dispersed five observatories were selected to analyze the effect of external environments on positioning accuracy and positioning errors according to location and time were compared as well as the number of visible satellites and position dilution of precision by observatory were analyzed to verify a correlation with positioning error.

• Proceedings of the Korean Society of Broadcast Engineers Conference
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• 2017.11a
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• pp.204-206
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• 2017

최근에 개인용 카메라를 통해 개인의 추억을 파노라마 영상으로 기록하는 것에 관심이 급증하고 있다. 파노라마 영상에 관심이 급증함에 따라 파노라마 영상을 제작하는 방법에 대해 여러 분야에서 연구가 많이 진행되고 있다. 일반적으로 개인용 카메라를 손으로 잡고 촬영하는 경우가 대부분이다. 손으로 잡고 촬영한 영상은 손 떨림에 의해 흔들린 영상이 된다. 이는 파노라마 영상을 만들 때 어려운 요소를 야기한다. 그러므로 흔들린 영상을 정합하고 안정화하는 연구는 매우 중요하다. 따라서 본 연구의 목적은 최근에 연구된 비디오 정합(Video Stitching)과 비디오 안정화(Video Stabilization)의 정확도 및 경향을 파악을 통해 빛의 변화가 빈번하고 움직임이 많은 콘서트 영상 정합에 이용될 아이디어 추출에 있다.

• Proceedings of the Korean Society of Broadcast Engineers Conference
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• 2017.11a
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• pp.74-76
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• 2017

In this paper, we introduce the CNN-based in-loop technology for HEVC, and analyze the performance of these algorithms through comparative experiments. The current in-loop filters in HEVC are composed of a deblocking filter that removes noise and a sample adaptive offset filter that compensates for signal offsets. A couple of CNN-based filters replacing the roles of these two algorithms are selected and compared.

• Proceedings of the Korean Society of Broadcast Engineers Conference
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• 2017.11a
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• pp.218-220
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• 2017

Recently, stitching techniques are used for obtaining wide FOV, e.g., panorama contents, from normal cameras. Despite many proposed algorithms, the no objective quality evaluation method is developed, so the comparison of algorithms are performed only in subjective way. The paper proposes a 'Delaunay-triangulation based objective assessment method' for evaluating the geometric and photometric distortions of stitched or warped images. The reference and target images are segmented by Delaunay-triangulation based on matched points between two images, the average Euclidian distance is used for geometric distortion measure, and the average or histogram of PSNR for photometric measure. We shows preliminary results with several test images and stitching methods for demonstrate the benefits and application.

• Proceedings of the Korean Society of Broadcast Engineers Conference
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• 2009.01a
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• pp.466-469
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• 2009

This paper presents a modified QIM-JPEG2000 steganography which improves the previous JPEG2000 steganography using quantization index modulation (QIM). Post-embedding changes in file size and PSNR by the modified QIM-JPEG2000 are smaller than those by the previous QIM-JPEG2000. Steganalysis experiments to determine whether messages are embedded in given JPEG2000 images show that the modified QIM-JPEG2000 is more secure than the previous QIMJPEG2000.

• Proceedings of the Korean Society of Broadcast Engineers Conference
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• 2009.01a
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• pp.689-694
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• 2009

We developed a facial image generating technique that can manipulate facial impressions. The present study applied this impression transferring method to higher-order impressions such as "elegance" or "attractiveness" and confirmed the psychological validity of this method using the semantic differential method. Subsequently, we applied this method to two types of cognitive experiments. First, we examined the contributions of texture and shape on the facial impressions by using those face images for which the impressions have already been quantitatively manipulated based on this method. Second, we used such stimuli to examine the effect of facial impressions and attractiveness on the "mere exposure effect." Thus, we concluded that the impression transfer vector method is an effective tool to quantitatively manipulate the facial impressions in various cognitive studies.

• Proceedings of the Korean Society of Broadcast Engineers Conference
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• 2009.01a
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• pp.673-677
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• 2009

In this paper, a transmitting process of a sequence of holograms describing 3D moving objects over the communicating wireless-network system is presented. A sequence of holograms involves holograms is transformed into a bit stream data, and then it is transmitted over the wireless LAN and Bluetooth. It is shown that applying this technique, holographic data of 3D moving object is transmitted in high quality and a relatively good reconstruction of holographic images is performed.

• Proceedings of the Korean Society of Broadcast Engineers Conference
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• 2009.01a
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• pp.703-708
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• 2009

The present paper describes the application of an improved impression transfer vector method (Sakurai et al., 2007) to transform the three basic dimensions (Evaluation, Activity, and Potency) of higher-order impression. First, a set of shapes and surface textures of faces was represented by multi-dimensional vectors. Second, the variation among faces was coded in reduced parameters derived by applying principal component analysis. Third, a facial attribute along a given impression dimension was analyzed to select discriminative parameters from among principal components with higher sensitivity to impressions, and obtain an impression transfer vector. Finally, the parametric coordinates were changed by adding or subtracting the impression transfer vector and the image was manipulated so that its facial appearance clearly exhibits the transformed impression. A psychological rating experiment confirmed that the impression transfer vector modulated three dimensions of higher-order impression. We discussed the versatility of the impression transfer vector method.

• Proceedings of the Korean Society of Broadcast Engineers Conference
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• 2009.01a
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• pp.566-571
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• 2009

A calibration method for multiple sets of stereo vision cameras is proposed. To measure the three-dimensional shape of a very long object, measuring the object at different viewpoints and registration of the data are necessary. In this study, two lasers beams generate two strings of calibration targets, which form straight lines in the world coordinate system. An evaluation function is defined to calculate the sum of the squares of the distances between each transformed target and the fitted line representing the laser beam to each target, and the distances between points appearing in the data sets of two adjacent viewpoints. The calculation process for the approximation method based on data linearity is presented. The experimental results show the effectiveness of the method.

• Proceedings of the Korean Society of Broadcast Engineers Conference
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• 2012.11a
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• pp.155-158
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• 2012

본 논문에서는 차량용 알고리즘 테스트를 위한 가상의 가랑비 영상 생성 방법을 제안한다. 기존의 차량용 알고리즘을 테스트 하는 경우 조명 및 기상 환경의 제약조건이 많이 따른다. 때문에 다양한 조명 및 기상환경에서 실험할 수 있는 시뮬레이션 환경이 요구된다. 이를 위해 본 논문에서는 가상의 기상환경 중 가랑비 영상 생성 방법을 제안한다. 구체적으로는 컴퓨터가 생성한 가상영상 대신에 실제 가랑비의 컬러 특성(color property)과 경계값 특성(edge property)을 분석한 결과를 토대로 가상의 가랑비를 생성하였다. 실험을 통해 실제 가랑비 영상과 생성된 가상의 가랑비 영상은 픽셀 값의 분포로 비교한 결과 두 영상이 아주 유사함을 확인하였다.