• Journal of Korea Multimedia Society
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• v.8 no.6
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• pp.844-855
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• 2005

This paper proposes a human action recognition scheme for Intelligent Web Browser. Based on the principle that a human action can be defined as a combination of multiple articulation movements, the inference of stochastic grammars is applied to recognize each action. Human actions in 3 dimensional (3D) world coordinate are measured, quantized and made into two sets of 4-chain-code for xy and zy projection planes, consequently they are appropriate for applying the stochastic grammar inference method. We confirm this method by experiments, that various physical actions can be classified correctly against a set of real world 3D temporal data. The result revealed a comparatively successful achievement of $93.8\%$ recognition rate through the experiments of 8 movements of human head and $84.9\%$ recognition rate of 60 movements of human upper body. We expect that this scheme can be used for human-machine interaction commands in a web browser.

• The Journal of the Korea Contents Association
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• v.11 no.11
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• pp.19-27
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• 2011

In this paper, we present an emulation library for the essential features and their API function calls provided by Direct3D, the most actively used API for computer game-related application programs on the MS-Windows-based desktop's, with OpenGL library in the Linux environment. In typical Linux-based systems, only the X window system and OpenGL graphics library are available. There are lots of needs for this kind of emulation library to convert the Direct3D-based game applications and user interfaces on these systems. Through carefully selecting the essential API functions from the DirectX version 9.0, we obtained the prototype implementation of that emulation library, to finally get the final full-scale DirectX implementation. Our implementation currently covers 3D coordinate transformations, light and material processing, texture mapping, simple animation features and more. We showed its feasibility through successfully executing a set of Direct3D demonstration programs including a real-world game character animation on our implementation.

• Proceedings of the Korean Institute of Information and Commucation Sciences Conference
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• 2022.05a
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• pp.587-588
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• 2022

In this paper, we propose a rigid body tracking method in 3D space using 2D passive marker images from multiple motion capture cameras. First, a calibration process using a chess board is performed to obtain the internal variables of individual cameras, and in the second calibration process, the triangular structure with three markers is moved so that all cameras can observe it, and then the accumulated data for each frame is calculated. Correction and update of relative position information between cameras. After that, the three-dimensional coordinates of the three markers were restored through the process of converting the coordinate system of each camera into the 3D world coordinate system, the distance between each marker was calculated, and the difference with the actual distance was compared. As a result, an error within an average of 2mm was measured.

• Journal of Korea Spatial Information System Society
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• v.5 no.1 s.9
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• pp.83-89
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• 2003

The GIS which is analysis of the real world to construction of 3D virtual city develop s in rapid growth. 3D virtual city is simulated by use of a GIS, Computer graphics, virtual reality and Spatial database. In this paper 3D topographical basemap which have the geographic coordinate of world was constructed by digital map. And build the Cyber city with combining the building that have elevation and 3D topographical basemap. By using server/client system for the cyber city. 3D cyber city web service implemented. We proposed the hybrid base web service method rather than the image or vector base web service. By the spatial and attribute search in the 3D Cyber City, overcome the existing simple visibility of Web 3D technology, and exhibited development direction to the Web 3D GIS.

• Proceedings of the Korea Institute of Convergence Signal Processing
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• 2001.06a
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• pp.173-176
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• 2001

In this thesis, a new measurement system is implemented for depth data extraction based on the camera calibration of the known pattern. The relation between 3D world coordinate and 2D image coordinate is analyzed. A new camera calibration algorithm is established from the analysis and then, the internal variables and external variables of the CCD camera are obtained. Suppose that the measurement plane is horizontal plane, from the 2D plane equation and coordinate transformation equation the approximation values corresponding minimum values using Newton-Rabbson method is obtained and they are stored into the look-up table for real time processing . A slit laser light is projected onto the object, and a 2D image obtained on the x-z plane in the measurement system. A 3D shape image can be obtained as the 2D (x-z)images are continuously acquired, during the object is moving to the y direction. The 3D shape images are displayed on computer monitor by use of OpenGL software. In a measuremental result, we found that the resolution of pixels have $\pm$ 1% of error in depth data. It seems that the error components are due to the vibration of mechanic and optical system. We expect that the measurement system need some of mechanic stability and precision optical system in order to improve the system.

• Journal of Korea Game Society
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• v.5 no.3
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• pp.3-10
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• 2005

We present the computer table tennis game using player's swing motion. We need to transform a real world coordinate into a virtual world coordinate in order to hit the virtual ball. We can not get a correct 3-dimension position of racket in environment that using one camera or simple image processing. Therefore we use Augmented Reality (AR) concept to develop the game. This paper shows the AR table tennis game using gesture and method to develop the 3D interaction game that only using one camera without any motion detection device or stereo cameras. Also, we use a scan line method to recognize gesture for speedy processing. The game is developed using ARtoolkit and DirectX that is popular tool of SDK for game development.

• Proceedings of the Korea Institute of Convergence Signal Processing
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• 2005.11a
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• pp.190-200
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• 2005

In this paper, the image modelling of road's lane markings is established using view frustum(VF) modeling. This algorithm also involve the real time processing of the 3D position coordinate and the distance data from the camera to the points on the 3D world coordinate by the camera calibration. In order to reduce their measurement error, an useful algorithm for which analyze the geometric variations clue to traveling vehicle's fluctuation using VF model is proposed. In experiments, without correction, for instance, the $0.4^{\circ}$ of pitching rotation gives the error of $0.4^{\sim}0.6m$ at the distance of 10m, but the more far distance cause exponentially the more error. We confirmed that this algorithm can be reduced less than 0.1m of error at the same condition.

• Proceedings of the Korean Institute of Intelligent Systems Conference
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• 2006.05a
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• pp.56-58
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• 2006

Camera calibration in machine vision is the process of determining the intrinsic cameara parameters and the three-dimensional (3D) position and orientation of the camera frame relative to a certain world coordinate system. On the other hand, Takagi-Sugeno-Kang (TSK) fuzzy system is a very popular fuzzy system and approximates any nonlinear function to arbitrary accuracy with only a small number of fuzzy rules. It demonstrates not only nonlinear behavior but also transparent structure. In this paper, we present a novel and simple technique for camera calibration for machine vision using TSK fuzzy model. The proposed method divides the world into some regions according to camera view and uses the clustered 3D geometric knowledge. TSK fuzzy system is employed to estimate the camera parameters by combining partial information into complete 3D information. The experiments are performed to verify the proposed camera calibration.

• Journal of the Optical Society of Korea
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• v.15 no.1
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• pp.30-37
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• 2011

Binocular-pair images obtained from two cameras can be used to calculate the three-dimensional (3D) world coordinate of a feature point. However, to apply this method, measurement accuracy of binocular vision depends on some structure factors. This paper presents an experimental study of measurement distance, baseline distance, and baseline direction. Their effects on camera reconstruction accuracy are investigated. The testing set for the binocular model consists of a series of feature points in stereo-pair images and corresponding 3D world coordinates. This paper discusses a method to increase the baseline distance of two cameras for enhancing the accuracy of a binocular vision system. Moreover, there is an inflexion point of the value and distribution of measurement errors when the baseline distance is increased. The accuracy benefit from increasing the baseline distance is not obvious, since the baseline distance exceeds 1000 mm in this experiment. Furthermore, it is observed that the direction errors deduced from the set-up are lower when the main measurement direction is similar to the baseline direction.

• Journal of the Korean Society for Precision Engineering
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• v.32 no.6
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• pp.537-542
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• 2015

The measurement of 3D shape is important in inspecting the quality of product. In this paper, we present a 3D shape measurement system of fastener using a camera and a slit laser. Calibration structure with slits is used in the extrinsic calibration of the camera and laser. The pose of the camera and laser is computed under the same world coordinate system in the calibration structure. Reflection of laser light on the metal surface causes many difficulties in the robust detection of them on image. We overcome this difficulty by using color and dynamic programming. Motor stage is used to rotate the fastener to recover the whole 3D shape of the surface of it.