• 한국HCI학회:학술대회논문집
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• 2009.02a
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• pp.631-636
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• 2009

Foreground segmentation methods have steadily been researched in the field of computer vision. Especially, background subtraction which extracts a foreground image from the difference between the current frame and a reference image, called as "background image" have been widely used for a variety of real-time applications because of low computation and high-quality. However, if the background scene was dynamically changed, the background subtraction causes lots of errors. In this paper, we propose an efficient background subtraction method in dynamic environment with both static and dynamic scene. The proposed method is a hybrid method that uses the conventional background subtraction for static scene and depth information for dynamic scene. Its validity and efficiency are verified by demonstration in dynamic environment, where a video projector projects various images in the background.

• Journal of KIISE:Software and Applications
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• v.31 no.12
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• pp.1611-1620
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• 2004

MPEG-4 supports dynamic scene composition through add/delete/replace of object or change of object's properties. Other existing MPEG-4 players focus on transmitting and playing the multimedia data according to MPEG-4 standard. It is insufficient for MPEG-4's characteristic such as playback of various objects and playback of dynamic scene composition. In this paper, we propose an effective scene compositor which is the core component of MPEG-4 player The scene compositor is an optimized processor that searches efficiently the scene graph, creates the data structure for independent management of object information and improves processing ability of user interaction. The scene compositor supports sufficiently scene description information, and is managed independently in player for component extension and application of mobile environment.

• Proceedings of the Korean Society of Broadcast Engineers Conference
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• 1999.06a
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• pp.15.1-21
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• 1999

Radiosity method is a global illumination model for image synthesis. It computes all energy interactions among diffuse elements in a virtual environment. One of the major drawbacks if its time consuming computation. Existing radiosity algorithms for static scene is difficult to be applicable to dynamic environments. In this paper we proposed an hierarchical scene partition scheme to speedup the link update computations in the dynamic environments. Since the proposed spatial data structure is global, it not only can be used to speedup the culling of non-affected links after geometry change, but also can be used to accelerate the subsequent visibility computation. Several empirical tests are given to show the efficiency of our improved algorithm.

• The Journal of Korea Robotics Society
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• v.3 no.3
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• pp.245-254
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• 2008

Recently, many vision-based navigation methods have been introduced as an intelligent robot application. However, many of these methods mainly focus on finding an image in the database corresponding to a query image. Thus, if the environment changes, for example, objects moving in the environment, a robot is unlikely to find consistent corresponding points with one of the database images. To solve these problems, we propose a novel navigation strategy which uses fast motion estimation and a practical scene recognition scheme preparing the kidnapping problem, which is defined as the problem of re-localizing a mobile robot after it is undergone an unknown motion or visual occlusion. This algorithm is based on motion estimation by a camera to plan the next movement of a robot and an efficient outlier rejection algorithm for scene recognition. Experimental results demonstrate the capability of the vision-based autonomous navigation against dynamic environments.

• 제어로봇시스템학회:학술대회논문집
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• 2000.10a
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• pp.311-311
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• 2000

We propose a DP-based formulation for matching line patterns by defining a robust and stable geometric representation that is based on the conceptual organizations. Usually, the endpoint proximity and collinearity of image lines, as two main conceptual organization groups, are useful cues to match the model shape in the scene. As the endpoint proximity, we detect junctions from image lines. We then search for junction groups by using geometric constraint between the junctions. A junction chain similar to the model chain is searched in the scene, based on a local comparison. A Dynamic Programming-based search algorithm reduces the time complexity for the search of the model chain in the scene. Our system can find a reasonable matching, although there exist severely distorted objects in the scene. We demonstrate the feasibility of the DP-based matching method using both synthetic and real images.

• Proceedings of the IEEK Conference
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• 2007.07a
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• pp.233-234
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• 2007

It is needed many images with different exposure to acquire high dynamic range (HDR) image of a scene using digital still camera. This paper proposed to acquire HDR image with small error using reduced number of image. Proposed method takes two pictures with different exposure and estimates dynamic range of scene using information two images, and takes three pictures with calculated proper exposure to acquire HDR image.

• Proceedings of the Korean Society of Broadcast Engineers Conference
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• 1995.06a
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• pp.77-81
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• 1995

Video composition is to integrate multiple image materials into one scene. It considerably enhances the degree of freedom in producing various scenes. However, we need to adjust the viewing point sand the image planes of image planes of image materials for high quality video composition. In this paper, were propose an intelligent video composition technique concentrating on the composition of CG and real scene. We first model the camera system. The projection is assumed to be perspective and the camera motion is assumed to be 3D rotational and 3D translational. Then, we automatically extract camera parameters comprising the camera model from real scene by a dedicated algorithm. After that, CG scene is generated according to the camera parameters of the real scene. Finally the two are composed into one scene. Experimental results justify the validity of the proposed method.

• Journal of the Korean Institute of Telematics and Electronics
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• v.26 no.8
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• pp.1247-1256
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• 1989

In this paper, we propose the dynamic scene segmentation algorithm using a cross mask and edge information. This method, a combination of the conventioanl feature-based and pixel-based approaches, uses edges as features and determines moving pixels, with a cross mask centered on each edge pixel, by computing similarity measure between two consecutive image frames. With simple calcualtion the proposed method works well for image consisting of complex background or several moving objects. Also this method works satisfactorily in case of rotaitional motion.

• Journal of the Korean Institute of Intelligent Systems
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• v.2 no.3
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• pp.22-28
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• 1992

One of the challenging problems in dynamic scene analysis is the correspondence problem. Points and lines have been two major entities for establishing the correspondence among suxcessive frmes and gave rise to discrete approach to dynamic scene analysis. SOme researchers take continuous approach to analyse the motion. There it is usually assumed that some sort of region correspondence has already been established. In this paper, we propose a method based on fuzzy membership function for solving region correspondence problem.

• The KIPS Transactions:PartB
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• v.9B no.3
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• pp.293-302
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• 2002

Gradual scene change detection is known as more difficult problem then abrupt scene change detection on video data analysis for contents based retrieval. In this paper, we present a new method for scene change detection far both abrupt and gradual change using the variable dynamic threshold arid cut frame difference (CFD). For this, We present the characteristics arid mathematical models of gradual transitions anti then, how can be detected by the CFD. And also we present new scene change detection algorithm based on cut frame difference. By the experimental result using real world video data indicate that the proposed method detect various scene changes both abrupt and gradual change efficiently without time-consuming computation and any dependency on a kind of gradual change effects.