• KSII Transactions on Internet and Information Systems (TIIS)
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• v.10 no.4
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• pp.1846-1863
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• 2016

High dynamic range (HDR) images can present the perfect real scene and rich color information. A commonly encountered problem in practical applications is how to well visualize HDR images on standard display devices. In this paper, we propose a multi-scale decomposition method using guided filtering for HDR image tone mapping. In our algorithm, HDR images are directly decomposed into three layers：base layer, coarse scale detail layer and fine detail layer. We propose an effective function to compress the base layer and the coarse scale detail layer. An adaptive function is also proposed for detail adjustment. Experimental results show that the proposed algorithm effectively accomplishes dynamic range compression and maintains good global contrast as well as local contrast. It also presents more image details and keeps high color saturation.

• Journal of Institute of Control, Robotics and Systems
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• v.16 no.2
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• pp.114-119
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• 2010

Network technology has been developed rapidly for digital service in these days. ZigBee, one of the IEEE 802.15.4 protocols, supporting local communication has become the core technology in the wireless network area. In this paper we designed an integrated fire monitoring system using a mobile robot and the ZigBee sensor nodes which are deployed to monitor fires. When a fire breaks out, the image information of the scene of a fire is transmitted by an autonomous mobile robot and we also monitor the current position of the robot. Furthermore, the data around the place where the fire breaks out and the positions of the sensor nodes can be transmitted to a server via the multi-hop communication in the real time.

• The Journal of Korea Robotics Society
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• v.17 no.3
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• pp.314-321
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• 2022

Depth information used in SLAM and visual odometry is essential in robotics. Depth information often obtained from sensors or learned by networks. While learning-based methods have gained popularity, they are mostly limited to RGB images. However, the limitation of RGB images occurs in visually derailed environments. Thermal cameras are in the spotlight as a way to solve these problems. Unlike RGB images, thermal images reliably perceive the environment regardless of the illumination variance but show lacking contrast and texture. This low contrast in the thermal image prohibits an algorithm from effectively learning the underlying scene details. To tackle these challenges, we propose multi-channel remapping for contrast. Our method allows a learning-based depth prediction model to have an accurate depth prediction even in low light conditions. We validate the feasibility and show that our multi-channel remapping method outperforms the existing methods both visually and quantitatively over our dataset.

• Journal of the Korea Computer Graphics Society
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• v.4 no.1
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• pp.67-77
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• 1998

In this paper we describe a development of a multi user game using 3D graphics and multicasting. First, we represent a virtual reality world by 3D graphics technology. Next, we use computer communication technology for the purpose of interaction among multi users. As a result, multi users share 3D graphics objects and play games. The goal of this paper is a development of a system that enables multi users to play games sharing a virtual world represented by 3D graphics. We use the OpenInventor library and C++ language for 3D graphics scene representation, and IP multicasting protocols for computer communication. The system allows to use Polhemus Fastrak 3D input device that recognizes the 3D position and 3D orientation. As an example we present a game that demonstrates the effect of piano concert by multi piano players who are distributed in a computer network.

• Korean Journal of Remote Sensing
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• v.32 no.6
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• pp.551-566
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• 2016

In the satellite remote sensing, the operational environment of the satellite sensor causes image degradation during the image acquisition. The degradation results in noise and blurring which badly affect identification and extraction of useful information in image data. Especially, the degradation gives bad influence in the analysis of images collected over the scene with complicate surface structure such as urban area. This study proposes a multi-stage image restoration to improve the accuracy of detailed analysis for the images collected over the complicate scene. The proposed method assumes a Gaussian additive noise, Markov random field of spatial continuity, and blurring proportional to the distance between the pixels. Point-Jacobian Iteration Maximum A Posteriori (PJI-MAP) estimation is employed to restore a degraded image. The multi-stage process includes the image segmentation performing region merging after pixel-linking. A dissimilarity coefficient combining homogeneity and contrast is proposed for image segmentation. In this study, the proposed method was quantitatively evaluated using simulation data and was also applied to the two panchromatic images of super-high resolution: Dubaisat-2 data of 1m resolution from LA, USA and KOMPSAT3 data of 0.7 m resolution from Daejeon in the Korean peninsula. The experimental results imply that it can improve analytical accuracy in the application of remote sensing high resolution panchromatic imagery.

• Proceedings of the IEEK Conference
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• 2005.11a
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• pp.549-552
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• 2005

This paper presents a 3D video content generation technique and system that uses the multi-view images and the depth map. The proposed uses 3-view video and depth inputs from the 3-view video camera and depth camera for the 3D video content production. Each camera is calibrated using Tsai's calibration method, and its parameters are used to rectify multi-view images for the multi-view stereo matching. The depth and disparity maps for the center-view are obtained from both the depth camera and the multi-view stereo matching technique. These two maps are fused to obtain more reliable depth map. Obtained depth map is not only used to insert a virtual object to the scene based on the depth key, but is also used to synthesize virtual viewpoint images. Some preliminary test results are given to show the functionality of the proposed technique.

• IEIE Transactions on Smart Processing and Computing
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• v.2 no.1
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• pp.27-35
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• 2013

This paper proposes a face tracking algorithm for a viewpoint adaptive multi-view synthesis system. The original scene captured by a depth camera contains a texture image and 8 bit gray-scale depth map. From this original image, multi-view images that correspond to the viewer's position can be synthesized using geometrical transformations, such as rotation and translation. The proposed face tracking technique gives a motion parallax cue by different viewpoints and view angles. In the proposed algorithm, the viewer's dominant face, which is established initially from a camera, can be tracked using the statistical characteristics of face colors and deformable templates. As a result, a motion parallax cue can be provided by detecting the viewer's dominant face area and tracking it, even under a heterogeneous background, and synthesized sequences can be displayed successfully.

• Proceedings of the Korean Society of Broadcast Engineers Conference
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• 2005.11a
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• pp.209-212
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• 2005

This paper introduces interactive multi-view contents authoring system based on MPEG-4. The MPEG-4 standard, which aims to provide an object based audiovisual coding tool, has been developed to address the emerging needs from communications, interactive broadcasting as well as from mixed service models resulting from technological convergence. Due to the feature of object based coding, it has been considered that MPEG-4 is the most suitable for interactive broadcasting content production. This feature is suitable for creation of the content which provides multiple views of object or scene in interactive manner. In this paper, we categorize the multi-view visual content into two types: panoramic multi-view content and object multi-view content. And design and implementation of the authoring system for interactive multi-view contents is presented. We believe that the proposed method can be effectively used for further deployment of MPEG-4 content to various interactive applications.

• Proceedings of the Korean Society of Broadcast Engineers Conference
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• 1996.06b
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• pp.88-93
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• 1996

We developed a visualization system for sports broadcasting that informs TV viewers of a sports player's sequential performing forms and locus in detail when gymnastic game such as‘vault’is broadcasted. It records the corresponding frames while a player is performing, extracts only the player's performing forms from background scenes by a proposed algorithm, superposes them sequentially on a background scene, and broadcasts them with slow speed. This system named as‘Multi-Motion’has ever been used in NHK live broadcasting for 1995 World Gymnastics Championships held in Japan.

• Proceedings of the Korean Society of Broadcast Engineers Conference
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• 2022.06a
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• pp.1275-1277
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• 2022

Structure-from-Motion(SfM), Multi-view Stereo(MVS)이 이용되는 3D Reconstruction 과정에서 생성된 3D 포인트 클라우드는 RGB 영상에 기반하여 생성되므로 실제 객체 혹은 Scene 과 달리 point 와 point 간에 존재하는 빈 공간이 발생한다. 이를 개선하기 위하여 3D 포인트 클라우드를 이용하여 3D Mesh 를 복원하는 Mesh Reconstruction 과정을 거치게 된다. 본 논문에서는 Mesh Reconstruction 과정에서 자유공간 지지도에 기반해 수정한 가중치를 이용하는 효율적인 방법을 제안한다. 실험을 통하여 제안한 알고리즘을 이용한 복원 결과가 기존보다 개선됨을 보인다.