• Journal of the Korea Computer Graphics Society
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• v.21 no.3
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• pp.1-10
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• 2015

One way to create a visually immersive environment is to utilize a front projection system. Especially, when enough space is not available behind the screen, it becomes difficult to install a back projection system, making the front projection an appropriate choice. A drawback associated with the front projection is, however, the interference of shadow. The shadow can be cast on the screen when the user is located between the screen and the projector. This shadow can negatively affect the user experience and reduce the sense of immersion by removing important information. There have been various attempts to eliminating shadows cast on the screen by using multiple projectors that compensate for each other with missing information. There is trade-off between calculataion time and desired accuracy in this mutual compensation. Accurate estimation of the shadow usually requires heavy computation while simple approaches suffer from inclusion of non-shadow regions in the result. We propose a novel approach to removing shadows created in the front projection system using the skeleton data obtained from a depth camera. The skeleton data helps accurately extract the shape of the shadow that the user cast without requiring much computation. Our method also utilizes a distance field to remove the afterimage of shadow that may occur when the user moves. We verify the effectiveness of our system by performing various experiments in an interactive environment created by a front projection system.

• Journal of Institute of Control, Robotics and Systems
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• v.19 no.3
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• pp.219-226
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• 2013

A distortion correction technique is presented to enhance the 3D scanning performance of a micro-size camera-projector system. Recently, several types of micro-size digital projectors and cameras are available. However, there have been few effort to develop a micro-size 3D scanning system. We develop a micro-sized 3D scanning system which is based on the structured light technique. Three images of phase-shifted sinusoidal patterns are projected, captured, and analyzed by the system to reconstruct 3D shapes of very small objects. To overcome inherent optical imperfection of the micro 3D sensor, we correct the vignetting and blooming effects which cause distortions in the phase image. Error analysis and 3D scanning results on small real objects are presented to show the performance of the developed 3D scanning system.

• Annual Conference of KIPS
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• 2003.11a
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• pp.601-604
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• 2003

본 논문은 프로젝션 화면에서 사용자와 컴퓨터간의 상호작용을 위한 인터페이스인 리바이저를 제안한다. 리바이저는 프로젝션 화면에서 사용자의 손 제스처로 문서교정 부호를 인식하여 전자문서를 교정하는 인터페이스 시스템이다. 프로젝션 화면에서 이러한 제스처를 인식하려면 두 가지 문제가 있다. 하나는 다양한 빛의 변화와 복잡한 배경을 가지는 프로젝션 화면에서 전방물체를 검출하는 것이고, 다른 하나는 사용자의 연속적인 움직임에서 사용자의 의도를 알아내는 것이다. 전방물체를 검출하기 위해 프로젝터로 입력되는 영상과 카메라에 의해 캡쳐된 영상 사이의 색상정보를 사용한다. 이 색상정보는 다양한 빛의 변화와 복잡한 배경에서 전방물체를 구별할 수 있게 한다. 연속된 제스처를 인식하기 위해 적출과 인식이 포함된 새로운 제스처 적출방법을 제안한다. 실험결과 제안된 시스템에서 의미없는 움직임이 포함된 제스처 시퀀스에서 사용자 제스처의 인식률은 평균 93.22%로 만족할만한 결과를 보였다.

• Proceedings of the Korean Information Science Society Conference
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• 2005.11b
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• pp.907-909
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• 2005

체감형 게임의 재미를 극대화 하기 위해서 몰입감있는 게임화면이 제공되어야 한다. 곡면, 반구형 스크린은 일반 평면 스크린을 사용할 때 보다 더 높은 몰입감을 줄 수 있지만 투사시 생기는 왜곡영상 보정에 많은 계산이 요구되는 문제가 있다. 정지된 영상(프리젠테이션 화면)이나 비디오 영상은 메모리 버퍼링을 통해 시스템이 요구하는 속도를 보장할 수 있으나, 사용자와 상호작용이 요구되는 게임에서는 사용자의 반응을 처리한 후 매 프레임 마다 빠른 워핑(warping) 처리를 요구하게 되는데, 렌더링될 화면을 미리 보정할 수가 없기 때문에 시스템 처리속도 저하의 원인이 된다. 본 논문에서는 체감형 게임을 곡면에 투사하는 방법과 GPU를 이용한 빠른 영상 보정을 제안함으로써 게임에서 요구하는 처리 속도를 보장하고 고해상도의 게임화면을 사용할 수 있도록 했다. 웹카메라를 이용하여 스크린과 프로젝터될 영상간의 호모그래피(homographpy)를 정의해서 워핑했고 워핑 연산을 HLSL로 작성하여 GPU를 이용했다. 실험결과로 반구형 스크린에서 몰입감 있는 AR 탁구게임을 보인다.

• Journal of the Institute of Electronics Engineers of Korea SP
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• v.45 no.2
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• pp.29-36
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• 2008

In this paper we propose a real-time method to estimate a pointing region from two camera images. In general, a pointing target exists in the face direction when a human points to something. Therefore, we regard the direction of pointing as the straight line that connects the face position with the fingertip position. First, the method extracts two points in the face and the fingertips region by using detecting the skin color of human being. And we used the 3D geometric information to obtain a pointing detection and its region. In order to evaluate the performance, we have build up an ICIGS(Interactive Cinema Information Guiding System) with two camera and a beam project.

• The Journal of the Korea Contents Association
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• v.14 no.1
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• pp.24-29
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• 2014

This paper proposes a kinect-based human motion recognition model for the 3D contents control after tracking the human body gesture through the camera in the infrared kinect project. The proposed human motion model in this paper computes the distance variation of the body movement from shoulder to right and left hand, wrist, arm, and elbow. The human motion model is classified into the movement directions such as the left movement, right movement, up, down, enlargement, downsizing. and selection. The proposed kinect-based human motion recognition model is very natural and low cost compared to other contact type gesture recognition technologies and device based gesture technologies with the expensive hardware system.

• The Journal of the Korea Contents Association
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• v.11 no.6
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• pp.98-105
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• 2011

Recent advances in computer technologies support real-time image processing and special effects on personal computers. This paper presents and analyzes a real-time interactive video system. The motivation of this work is to realize an artistic concept that aims at transforming the timeline visual variations in a video of sea water waves into sound in order to provide an audience with an experience of overlapping themselves onto the nature. In practice, the video of sea water waves taken on a beach is processed using an optical flow algorithm in order to extract the information of visual variations between the video frames. This is then masked by the silhouette of an audience and the result is projected on a gallery space. The intensity information is extracted from the resulting video and translated into piano sounds accordingly. This work generates an interactive space realizing the intended concept.

• Journal of the Institute of Electronics Engineers of Korea CI
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• v.41 no.1
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• pp.27-37
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• 2004

The detection of foreground objects in a projection display using color information can be hard due to changing lighting conditions and complex backgrounds. Accordingly, the current paper proposes a foreground object detection method using color information that is obtained from the input image to the Projector and an image captured by a camera above the projection display. After pixel correspondences between the two images are found by calibrating the geometry distortion and color distortion, the natural color variations are estimated for the projection display. Then, any pixel that has another variation not resulting from natural geometry or color distortion is considered a part of foreground objects, because a foreground object in a projection display changes the values of pixels. As shown by experimental results, the proposed foreground detection method is applicable to an interactive projection display system such as the DigitalDesk