• 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 the Korea Institute of Information and Communication Engineering
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• v.23 no.12
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• pp.1492-1499
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• 2019

This paper propose how to track the position of the observer to control the viewing zone using an adaptive parallax barrier. The pose is estimated using a Constrained Local Model based on the shape model and Landmark for robust eye-distance measurement in the face pose. Camera's correlation converts distance and horizontal location to centimeter. The pixel pitch of the adaptive parallax barrier is adjusted according to the position of the observer's eyes, and the barrier is moved to adjust the viewing area. This paper propose a method for tracking the observer in the range of 60cm to 490cm, and measure the error, measurable range, and fps according to the resolution of the camera image. As a result, the observer can be measured within the absolute error range of 3.1642cm on average, and it was able to measure about 278cm at 320×240, about 488cm at 640×480, and about 493cm at 1280×960 depending on the resolution of the image.

• Journal of the Korean Institute of Landscape Architecture
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• v.35 no.2 s.121
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• pp.55-63
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• 2007

The purpose of this study is to create a planting design for progressive realization. For this, visual preferences as measured via questionnaire were evaluated by the Scenic Beauty Estimation(SBE) and paired comparison methods. The results can be summarized as follows. Through photo observation, the average visual blockage ratio was 38% and the range of degree of the visual blockage ratio was $30{\sim}50%$. The sketch simulation and filtered pattern received the highest preference score and fumed out to be the most practical pattern out of all the patterns evaluated. Also, in the sketch simulation, the high preference values were observed for a distance of 9 to 12m from the view point to the blockage tree with a D/H ratio of 2. The preference score significantly decreased with the increase of the visual blockage ratio having a turning point at $30{\sim}35%$ of the visual blockage ratio, even though the distance parameters were more important than the visual blockage ratio in the scores. An outstanding view must be handled properly to be preserved or accentuated. Framed, open, enclosed, screened or filtered pattern views should be completely revealed only from their best vantage point, not given away at first glimpse. It this sense, parallax spatial beauty with trees could be improved through the visual aspects of plan arrangements and seems to be an effective design technique for landscape planning and planting design.

• Proceedings of the Korean Society of Broadcast Engineers Conference
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• 2011.11a
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• pp.333-336
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• 2011

스테레오스코픽 3D 입체영상은 좌/우 영상의 시차(視差)를 이용하여 시청자로 하여금 2D 영상에서 느낄 수 없었던 가상의 입체감을 느낄 수 있도록 한다. 이러한 가상의 입체감은 주로 좌/우 영상의 수평시차를 통해서 구현되며, 수평시차의 많고 적음에 의하여 피사체의 원근(遠近)이 조절된다. 시차가 지나치게 작을 경우 3D 입체영상은 2D와 다를 바 없이 평면으로 보이거나, 피사체의 볼륨감이 사라져서 종이인형들이 단순히 층을 나뉘어서 배열된 것처럼 보이게 된다. 반대로 시차가 지나치게 클 경우 좌/우 영상은 하나로 융합되어 입체감을 형성하지 못하고 이중상으로 관측되게 된다. 이렇듯 3D 입체영상에서 수평시 차의 크기는 핵심적인 기능을 수행하고 있음에도, 프로그램 제작시 적절한 시차를 결정하는 판단기준이 부족하며 최대 시차에 대한 기준도 모호하여, 촬영자나 컴퓨터 그래픽스 작업자의 감(感)에 의하여 입체영상 콘텐츠 제작이 이루어지고 있어, 고품질 3D 영상 제작의 장애요인이 되고 있다. 본 논문에서는 NPP(Native Pixel Parallax) 계산을 바탕으로 입체영상의 시차는 스크린 크기별로 달라질 수 있음을 살펴보고, 좌/우 영상의 시차가 가상깊이로 환산되는 과정을 분석하여, 3D 방송에 적합한 최대 시차를 제안하고자 한다.

• Korean Journal of Remote Sensing
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• v.21 no.5
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• pp.383-392
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• 2005

Vegetation classes, especially grass and tree classes, are often confused in classification when conventional spectral pattern recognition techniques are used to classify urban areas. This paper reports on a study to improve the classification results by using an automated process of considering height information in separating urban vegetation classes, specifically tree and grass, using three-band, high-spatial resolution, digital aerial imagery. Height information was derived photogrammetrically from stereo pair imagery using cross correlation image matching to estimate differential parallax for vegetation pixels. A threshold value of differential parallax was used to assess whether the original class was correct. The average increase in overall accuracy for three test stereo pairs was $7.8\%$, and detailed examination showed that pixels reclassified as grass improved the overall accuracy more than pixels reclassified as tree. Visual examination and statistical accuracy assessment of four test areas showed improvement in vegetation classification with the increase in accuracy ranging from $3.7\%\;to\;18.1\%$. Vegetation classification can, in fact, be improved by adding height information to the classification procedure.

• Korean Journal of Optics and Photonics
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• v.32 no.1
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• pp.22-28
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• 2021

We try to extract three-dimensional information, such as the distance from a camera and the actual width and height of an object, from still photographs by a multilens smartphone camera, by means of parallax error. To obtain this information, we develop several formulas and design a method for experimental instrumentation. If the results from this paper were included in algorithms of multilens smartphone cameras, there would be various kinds of applications, such as in the workplace of architectural and civil engineering to obtain an actual dimension, or on a golf course to measure how far away a pin flag is. We expect many more applications of this study, because the multilens smartphone camera is already an important necessity of life.

• Journal of the Korean Society of Surveying, Geodesy, Photogrammetry and Cartography
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• v.36 no.4
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• pp.287-293
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• 2018

It is prerequisite to generate epipolar resampled images by reducing the y-parallax for accurate and efficient processing of satellite stereo images. Minimizing y-parallax requires the accurate sensor modeling that is carried out with ground control points. However, the approach is not feasible over inaccessible areas where control points cannot be easily acquired. For the case, a relative orientation can be utilized only with conjugate points, but its accuracy for satellite sensor should be studied because the sensor has different geometry compared to well-known frame type cameras. Therefore, we carried out the bias-compensation of RPCs (Rational Polynomial Coefficients) without any ground control points to study its precision and effects on the y-parallax in epipolar resampled images. The conjugate points were generated with stereo image matching with outlier removals. RPCs compensation was performed based on the affine and polynomial models. We analyzed the reprojection error of the compensated RPCs and the y-parallax in the resampled images. Experimental result showed one-pixel level of y-parallax for Kompsat-3 stereo data.

• The Bulletin of The Korean Astronomical Society
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• v.27 no.1
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• pp.58-58
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• 2002

• 한국정보디스플레이학회:학술대회논문집
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• 2004.08a
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• pp.440-441
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• 2004

A volumetric three-dimensional (3D) display system was presented, which utilizes a rotating two-dimensional (2D) display panel of light emitting diodes (LEDs) to generate more than 10 million volume pixels (voxels) within a cylindrical volume of 165 mm in height and 292 mm in diameter. Due to persistence of vision, momentarily addressed voxel information is perceived and fused into a 3D image. Important cues for depth perception, such as binocular parallax, accommodation, convergence and motion parallax are satisfied automatically and naturally, thus it is suitable for individual or group viewing, without the need for any special visual aids.

• Proceedings of the Optical Society of Korea Conference
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• 2002.07a
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• pp.24-25
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• 2002

밀레니움을 전후하여 세계적으로 8m급 초대형 망원경들이 만들어지고 있다. ESO (European Southern Observatory)의 VLT (Very Large Telescopes) 4기, 미국 영국 카나다 등의 연합 Gemini telescope 2기, 일본의 Subaru 1기 등, 10여기의 망원경들이 완성되었고, 차세대 망원경들이 50m급으로 디자인되고 있다. 우주망원경도 지름 2.4m인 허블 우주망원경(Nubble Space Telescope)의 뒤를 이어 6m급의 차세대 우주망원경 (Next Generation Space Telescope)이 개발되고 있어서 2010년경에 발사될 예정이다. (중략)