• Journal of the Korea Society of Computer and Information
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• v.16 no.12
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• pp.93-102
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• 2011

This paper presents a walking guidance system for blind pedestrians in an outdoor environment using just one single camera. Unlike many existing travel-aid systems that rely on stereo-vision, the proposed system aims to get necessary information of the road environment by using just single camera fixed at the belly of the user. To achieve this goal, a top-view image of the road is used, on which obstacles are detected by first extracting local extreme points and then verified by the polar edge histogram. Meanwhile, user motion is estimated by using optical flow in an area close to the user. Based on these information extracted from image domain, an audio message generation scheme is proposed to deliver guidance instructions via synthetic voice to the blind user. Experiments with several sidewalk video-clips show that the proposed walking guidance system is able to provide useful guidance instructions under certain sidewalk environments.

• Journal of the Korean Society of Surveying, Geodesy, Photogrammetry and Cartography
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• v.19 no.4
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• pp.373-383
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• 2001

This study conducted pilot mapping project to know the possibility of mapping with medium resolution satellite imageries. For this purpose, mapping experiments were conducted with each stereo model imageries of SPOT, KOMPSAT, and IRS- lC. And positional accuracy, analysis of detectable and describable features, and comparison with existing digital map were checked, possible mapping scale and cost analysis were conducted with these results. Regarding SPOT imagery, digital photogrammetric workstation was used for stereoplotting. Regarding KOMPSAT and IRS-lC imageries, because there were data format support problems. head-up digitizing was performed with ortho imageries rectified with DEMs generated by image matching. The results of experiments show that such features as wide road, river, coast line, etc are possible to detect and depict but many other features are not for SPOT, KOMPSAT, and IRS-lC imageries. On the aspect of mapping, therefore, SPOT is available for 1/50,000 topographic map revision, KOMPSAT and IRS-lC for 1/25.000 topographic map revision.

• Journal of the Korean Society of Surveying, Geodesy, Photogrammetry and Cartography
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• v.27 no.5
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• pp.529-534
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• 2009

In this study, we investigate the feasibility of modeling entire image strips that has been acquired from the same orbital segments. We tested sensor models based on satellite orbit and attitude with different sets(Type1 ~ Type4) of unknowns. We checked the accuracy of orbit modeling by establishing sensor models of one scene using control points extracted from the scene and by applying the models to adjacent scenes within the same orbital segments. Results indicated that modeling of individual scenes with 1st or 2nd order unknowns was recommended. We tested the accuracy of around control points, digital map using the HIST-DPW (Hanjin Information Systems & Telecommunication Digital Photogrammetric Workstation) As a result, we showed that the orbit-based sensor model is a suitable sensor model for making 1/25,000 digital map.

• Proceedings of the KSR Conference
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• 2009.05a
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• pp.1003-1009
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• 2009

The Spatial Image contents of Geomorphology 3-D environment is focused by the requirement and importance in the fields such as, national land development plan, telecommunication facility management, railway construction, general construction engineering, Ubiquitous city development, safety and disaster prevention engineering. The currently used DEM system using contour lines, which embodies geographic information based on the 2-D digital maps and facility information has limitation in implementation in reproducing the 3-D spatial city. Moreover, this method often neglects the altitude of the rail way infrastructure which has narrow width and long length. This As the results, We confirmed the solutions of varieties application for railway facilities management using 3-D spatial image contents and database design. Also, I suggested that U-city using railway modeling about matching methods of high density elevation value using 3-D aerial photo with laser data are best approach for detail stereo modeling and simulation.

• Korean Journal of Remote Sensing
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• v.26 no.4
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• pp.439-449
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• 2010

This paper reports experiments and analysis work done to find out the cause of Y parallex for stereo pairs of KOMPSAT-2 images and means to improve the Y parallex problem. We could conclude that the Y parallex problem was caused by resampling errors of KOMPSAT-2 PANchromatic bands, induced by the process of warping PANchromatic band with reference to multispectral bands. We could also conclude that a rigorous warping process could improve resampling of KOMPSAT-2 PANchromatic band and remove the Y parallex problem significantly. We also confirmed that a rigorous warping process could also remove blocky brightness patterns present on KOMPSAT-2 PANchromatic band. Therefore, by implementing more rigorous warping process within KOMPSAT-2 scene generation procedures, KOMPSAT-2 geometric and radiometric quality will be improved.

• Journal of Practical Engineering Education
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• v.12 no.2
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• pp.309-319
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• 2020

Billiards is a fun and popular sport, but both route planning and cueing prevent beginners from becoming skillful. A beginner in billiards requires constant concentration and training to reach the right level, but without the right motivating factor, it is easy to lose interests. This study aims to induce interest in billiards and accelerate learning by utilizing billiard path prediction and visualization on a highly immersive augmented reality platform that combines a stereo camera and a VR headset. For implementation, the placement of billiard balls is recognized through the OpenCV image processing program, and physics simulation, path search, and visualization are performed in Unity Engine. As a result, accurate path prediction can be achieved. This made it possible for beginners to reduce the psychological burden of planning the path, focus only on accurate cueing, and gradually increase their billiard proficiency by getting used to the path suggested by the algorithm for a long time. We confirm that the proposed AR billiards is remarkably effective as a learning assistant tool.

• Tunnel and Underground Space
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• v.19 no.6
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• pp.517-525
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• 2009

Stereophotogrammetry is used to extract spatial information of an interested object by constructing a stereo-image from two or more photos. In this study, the stereophotogrammetry was adopted for a rock joint survey in mine tunnels. The orientations of discontinuities were measured from two mine tunnels with a clinocompass. To evaluate the effect of photographing light level on the stereophotogrammetry analysis, the light intensity was changed within a predefined range for every photograph. Those photographs were analyzed by using a commercial code for stereophotogrammetry - ShapeMetriX 3D, and the results from the analysis were compared with the manual measurement using a clinocompass.

• Proceedings of the Korean Society of Broadcast Engineers Conference
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• 2010.11a
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• pp.311-314
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• 2010

최근 3D 영상에 대한 대중화가 급속히 진행되고 있음에도 불구하고 한 번 만들어진 영상/비디오를 재사용하거나 조작하여 다양한 형태의 콘텐츠를 만들지 못하고 있다. 본 논문에서는 깊이영상과 양안(스테레오) 영상 또는 깊이영상과 단안 영상이 주어졌다고 가정하고 깊이영상을 조작하여 양안 시차(parallax)를 변화시키는 방법을 제안한다. 시차변화의 대상은 부분영상이며, 특정 개체를 추출하여 깊이정보를 수정하고, 이를 바탕으로 스테레오 영상을 재구성한다. 본 논문에서는 정지영상만을 대상으로 하며, 동일한 방법을 동영상에 적용하면 동영상 또한 시차를 변화시킨 결과를 얻을 수 있다. 실험은 Middlebury의 테스트 영상들을 대상으로 제안한 방법을 적용하여 자연스러운 스테레오 영상을 얻을 수 있음을 보인다.

• Journal of Korea Multimedia Society
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• v.18 no.9
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• pp.1008-1018
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• 2015

In this paper, we propose a method that constructs a saliency map in which important regions are accurately specified and the colors of the regions are less influenced by the similar surrounding colors. Our method utilizes LBP(Local Binary Pattern) histogram information to compare and analyze texture information of surrounding regions in order to reduce the effect of color information. We extract the saliency of stereoscopic images by integrating a 2D saliency map with depth information of stereoscopic images. We then measure the distance between two different sizes of the LBP histograms that are generated from pixels. The distance we measure is texture difference between the surrounding regions. We then assign a saliency value according to the distance in LBP histogram. To evaluate our experimental results, we measure the F-measure compared to ground-truth by thresholding a saliency map at 0.8. The average F-Measure is 0.65 and our experimental results show improved performance in comparison with existing other saliency map extraction methods.

• Proceedings of the Korean Society of Broadcast Engineers Conference
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• 2008.11a
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• pp.117-120
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• 2008

본 논문은 스테레오 비디오 데이터 압축 및 복원을 위한 그리드(Grid) 기반 2D 워핑 방법을 제안한다. 스테레오 비디오에 대한 데이터 표현 방법으로 깊이지도 및 매쉬(mesh)를 이용한 방법이 주로 사용되어 왔으며 매쉬를 이용한 방법은 두 영상간의 매칭되는 노드를 이용하여 데이터 압축 효율을 높일 수 있다. 그러나, 두 영상에서 매칭되는 노드의 위치를 찾는 것은 매우 어려운 일일 뿐만 아니라 매쉬에 의해서 워핑된 영상과 목적이 되는 스테레오 영상의 좌측 또는 우측 영상간의 왜곡이 불가피하다. 따라서 이러한 왜곡을 보정하기 위하여 잔여영상(Residual image) 정보를 추가로 요구하게 된다.제안된 논문은 이러한 잔여영상 정보를 최소화 하기 위하여 반복적으로 2D워핑을 수행하며 최적화된 워핑 영상을 생성함으로써 목적영상과의 오차를 최소로 유지하여 추가정보인 잔여 영상의 데이터 용량을 최소화 한다. 전체영상에 대하여 2D워핑을 수행하며 각각의 노드를 변경하는 것은 많은 비용을 감수해야 하기 때문에 오차영역에 대하여 지역단위로 분할하고 단계적으로 최적화를 이루는 분할정복 방법을 사용하였다. 본 논문의 실험에서는 스테레오 영상에 대하여 각각의 신호대 잡음비(PSNR)를 통해 제안한 방법의 품질을 평가하였을 뿐만 아니라 기존의 메쉬 기반한 방법과 깊이지도를 이용한 방법과의 데이터량을 비교하였다. 실험결과를 통하여 제안한 방법의 데이터 압축의 효율성 및 품질의 우수성을 확인하였다.