• 대한공간정보학회지
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• 제6권2호
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• pp.11-20
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• 1998

수치지도를 생성하거나 갱신하기 위해 항공사진측량을 이용하지만 각종 지상시설물에 대한 위치와 속성자료를 항공사진측량만으로 작성하기 어려우므로 현장조사를 통해 지상시설물에 대한 정보를 얻고 있다. 따라서 본 연구에서는 현장조사의 정확도와 신뢰성을 향상시키기 위해 고해상 디지털카메라에 의해 입체영상을 얻고 DLT기법을 적용하여 3차원위치결정을 할 수 있는 비디오사진측량기법을 개발하였다. 또한 개발된 비디오 사진측량기법은 생성된 3차원위치자료에 속성자료를 연결시키는 기능을 이용하여 수치지도의 위치와 속성자료를 생성 및 갱신 할 수 있도록 개발하였다.

• 대한공간정보학회지
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• 제11권4호
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• pp.13-19
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• 2003

본 연구는 비측량용 디지털 비디오 카메라를 이용하여 석조문화재인 석탑을 대상으로 촬영하였다. 비측량용 카메라인 디지털 비디오 카메라는 기존의 측량용 또는 준측량용 카메라에서 하지 못하는 방법이 있으며, 이는 촬영된 동영상을 가지고 분석하고자 하는 부분을 손쉽게 정지영상으로 취득할 수가 있었다. 비측량용인 디지털 비디오 카메라로 문화재 3차원 해석에 있어서 $2mm{\sim}4mm$의 정확도를 얻을 수 있었다. 차후 문화재 원형 보존에 대한 계획의 수행에 있어서 문화재에 대한 자세한 정보를 제공하기 위해 효율적이고 경제적인 방법을 제시하고자 한다.

• KSII Transactions on Internet and Information Systems (TIIS)
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• 제6권4호
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• pp.1128-1139
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• 2012

With the development of three-dimensional display and related technologies, depth video coding becomes a new topic and attracts great attention from industries and research institutes. Because (1) the depth video is not a sequence of images for final viewing by end users but an aid for rendering, and (2) depth video is simpler than the corresponding color video, fast algorithm for depth video is necessary and possible to reduce the computational burden of the encoder. This paper proposes a fast mode decision algorithm for depth video coding based on depth segmentation. Firstly, based on depth perception, the depth video is segmented into three regions: edge, foreground and background. Then, different mode candidates are searched to decide the encoding macroblock mode. Finally, encoding time, bit rate and video quality of virtual view of the proposed algorithm are tested. Experimental results show that the proposed algorithm save encoding time ranging from 82.49% to 93.21% with negligible quality degradation of rendered virtual view image and bit rate increment.

• 방송공학회논문지
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• 제2권2호
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• pp.125-135
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• 1997

This paper is concerned with realistic mainpulation of content in video sequences. Manipulation of content in video sequences is one of the content-based functionalities for MPEG-4 Visual standard. We present an approach to synthesizing video sequences by using the intermediate outputs of three-dimensional (3D) motion and depth analysis. For concreteness, we focus on video showing 3D motion of an observer relative to a scene containing planar runways (or roads). We first present a simple runway (or road) model. Then, we describe a method of identifying the runway (or road) boundary in the image using the Point of Heading Direction (PHD) which is defined as the image of, the ray along which a camera moves. The 3D motion of the camera is obtained from one of the existing 3D analysis methods. Then, a video sequence containing a runway is manipulated by (i) coloring the scene part above a vanishing line, say blue, to show sky, (ii) filling in the occluded scene parts, and (iii) overlaying the identified runway edges and placing yellow disks in them, simulating lights. Experimental results for a real video sequence are presented.

• 한국방송∙미디어공학회:학술대회논문집
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• 한국방송공학회 2002년도 정기총회 및 학술대회
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• pp.169-172
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• 2002

Embedding information into video data is a topic that recently gained increasing attention. This paper proposes a new approach for digital watermarking and secure copyright protection of video, the principal aim being to discourage illicit copying and distribution of copyrighted material. The method presented here is based on the three dimensional discrete cosine transform of video scene, in contrast with previous works on video watermarking where each video frame was marked separately, or where only intra-frame or motion compensation parameters were marked in MPEG compressed videos. The watermark sequence used is encrypted, pseudo-noise signal to the video. The performance of the presented technique is evaluated experimentally

• Archives of Plastic Surgery
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• 제50권1호
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• pp.125-129
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• 2023

Three-dimensional (3D) video exoscopes are high-magnification stereo cameras that project onto monitors mounted in the operating room, viewable from different angles. Outside of plastic surgery, exoscopes have been shown to successfully improve the ergonomics of microsurgery, though sometimes with prolonged operating times. We compare a single surgeon's early experience performing free flap procedures from 2020 to 2021 using either a binocular microscope or a 3D video exoscope. Ten procedures were performed with the standard operating microscope and 8 procedures with the 3D exoscope. The microsurgeon, having minimal prior experience using an exoscope, reported less neck discomfort following the free flap procedures performed with the exoscope compared with the binocular surgical microscope. Total average operating time was comparable between the standard surgical microscope and the 3D exoscope (13.7 vs. 13.4 hours, p = 0.34). Our early experience using a 3D exoscope in place of a standard optical microscope demonstrated that the exoscope shows promise, offering an ergonomic alternative during microvascular reconstruction without increasing overall operating times. Future studies will compare free flap ischemia time between cases performed using the exoscope and the conventional binocular microscope. Medical Subject Headings authorized following words: free tissue flaps; operating rooms; ergonomics; microsurgery.

• Physical Therapy Rehabilitation Science
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• 제3권1호
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• pp.7-12
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• 2014

Objective: The purpose of this study was to investigate the effects of a three dimensional balance trainer in combination with a video-game system and visual feedback on balance recovery and gait function in subacute stroke patients. Design: Randomized controlled trial. Methods: Twenty-three subacute stroke patients were assigned to either an experimental (n=12) or a control group (n=11) using a random permuted block design and sealed envelopes. The experimental group received additional 3-dimensional balance training combined with visual feedback and a game program for 30 min/day, 5 days/week for 4 weeks. Both groups received 30-min of conservative physical therapy sessions based on neurodevelopmental therapy. Before and after the 20 sessions, walking abilities were evaluated by the the GaitRite system and balances were evaluated using the Berg Balance Scale (BBS). The Trunk Impairment Scale (TIS) was used to assess trunk muscle performances. Results: After the 4-week intervention, BBS and TIS scores were significantly increased in both groups (p<0.05), and increases in these scores were significantly greater in the experimental group (p<0.05). After the 4-week intervention, gait speed and cadence were significantly increased in both groups (p<0.05), and as was observed for BBS and TIS scores, changes of gait speed and cadence were significantly greater in the experimental group (p<0.05). Conclusions: The study shows that the 3-dimensional balance trainer combined with visual biofeedback and a video-game system provides a therapeutic means for improving balance and gait ability in subacute stroke patients.

• 한국해안해양공학회지
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• 제7권1호
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• pp.70-74
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• 1995

고화질의 그래픽 컴퓨터와 영상장치를 이용한 지진해일의 전파 및 이에 부수되는 쳐오름 과정의 3차원 영상화에 관하여 기술하였다. 실제로, 1960년 칠레지진에 의해 발생한 지진해일이 태평양에서 진행하는 과정 및 하와이 힐로만에서의 범람하는 과정에 관한 수치해석의 결과를 3차원으로 영상화하였다.

• Journal of Electrical Engineering and Technology
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• 제7권6호
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• pp.990-1000
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• 2012

In this paper, we propose an algorithm that creates three-dimensional (3D) stereoscopic video from two-dimensional (2D) video encoded by H.264 instead of using two cameras conventionally. Very accurate motion vectors are available in H.264 bit streams because of the availability of a variety of block sizes. 2D/3D conversion algorithm proposed in this paper can create left and right images by using extracted motion information. Image type of a given image is first determined from the extracted motion information and each image type gives a different conversion algorithm. The cut detection has also been performed in order to prevent overlapping of two totally different scenes for left and right images. We show an improved performance of the proposed algorithm through experimental results.

• 대한원격탐사학회:학술대회논문집
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• 대한원격탐사학회 2002년도 Proceedings of International Symposium on Remote Sensing
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• pp.117-122
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• 2002

In this paper, we propose Media GIS web service architecture using 3D geographical database and GPS-related data resulted from 4S-Van. We introduce a novel interoperable geographical data service concept; so-called, Virtual World Mapping (VWM) that can map 3D graphic world with real-world video. Our proposed method can easily retrieve geographical in-formation and attributes to reconstruct 3D virtual space according to certain frame in video sequences. Our proposed system architecture also has an advantage that can provide geographical information service with video stream without any image processing procedures. In addition to, describing the details of our components, we present a Media GIS web service system by using GeoVideo Server, which performs VWM technique.