• Journal of Korea Multimedia Society
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• v.21 no.10
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• pp.1162-1170
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• 2018

This paper presents an augmented reality system for multiple users. The proposed system performs ar image-based pose estimation of users and pose of each user is shared with other uses via a network server. For camera-based pose estimation, we install multiple markers in a pre-determined space and select the marker with the best appearance. The marker is detected by corner point detection and for robust pose estimation. the marker's corner points are tracked by optical flow tracking algorithm. Experimental results show that the proposed system successfully provides an augmented reality application to multiple users even when users are rapidly moving and some of markers are occluded by users.

• Korean Journal of Cognitive Science
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• v.15 no.4
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• pp.49-59
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• 2004

An eye-tracking experiment was conducted to examine resolving processes of grammatical marking ambiguities of Korean. and to evaluate predictions from the garden-path model and the constraint-based models on the processing of Korean morphological information. The complex NP clause structure that can be parsed according to the minimal attachment principle was compared to the embedded relative clause structures that have one of the nominative marker (-ka), the delimiter (-man, which roughly corresponds to the English word 'only'), or the topic marker (-nun) on the first NPs. The results clearly showed that Korean marking ambiguities are resolved by the minimal attachment principle, and the topic marker affects reparsing procedures. The pattern of eye fixation times was more compatible with the garden-path model, and was not consistent with the predictions of the constraint-based accounts. Suggestions for further studies were made.

• Proceedings of the Korea Contents Association Conference
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• 2014.11a
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• pp.213-214
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• 2014

본 논문에서는 증강현실 저작도구를 사용 할 때 마커인식을 통하여 동영상의 Tracking 데이터를 추출하는 방법을 제안한다. 실험에 이용한 마커는 직사각형모양의 특징점이 잘 나타나는 물체로서, 사각형 마커인식을 위해 CornerDetection과 Matching기법을 사용하였다. Tracking을 활용하는 방식에는 동영상의 기준프레임을 활용하여 Tracking하는 방법과 각 프레임을 순차적으로 Tracking하여 비교하는 방법, 그리고 마커를 사용하지 않고 동영상의 Tracking데이터를 추출하는 방법이 있는데 본 논문에서는 이 세 가지 방법을 비교하여, 증강현실 저작도구의 상용화를 위한 최적화된 알고리즘을 제안한다.

• Journal of Advanced Navigation Technology
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• v.14 no.2
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• pp.272-277
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• 2010

AR(Augmented Reality) needs medium between real and virtual, world, and recognition techniques are necessary to track an object continuously. Optical tracking using marker is mainly used, but it takes time and is inconvenient to attach marker onto the target objects. Therefore, many researchers try to develop markerless tracking techniques nowaday. In this paper, we extract features and 3D position from 3D objects and suggest realtime tracking based on these features and positions, which do not use just coplanar features and 2D position. We extract features using SURF, get rotation matrix and translation vector of 3D object using POSIT with these features and track the object in real time. If the extracted features are nor enough and it fail to track the object, then new features are extracted and re-matched to recover the tracking. Also, we get rotation in matrix and translation vector of 3D object using POSIT and track the object in real time.

• 한국HCI학회:학술대회논문집
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• 2009.02a
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• pp.542-546
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• 2009

This paper introduces a Mixed-Reality based Software technology in Smart-Phone Environment. The field of Mixed-Reality in mobile environment is relatively young. but Cause to develop Mobile infra and improvement of mobile device, open-platform mobile OS, the request extended This paper suggest the method for Marker Detection and Marker Tracking method. This method is the one of some kind of a base-technology in Mixed Reality. this method is to effect to location and registration. This paper suggest the method in low CPU computing power. Using a deformable searching area, the method improve computing power. and Using a Cam-shift algorithm, we suggest a calibration free method.

• Korean Journal of Computational Design and Engineering
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• v.17 no.3
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• pp.208-215
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• 2012

Augmented reality can help to improve user's engineering abilities such as perception and decision making in industry field. Therefore we have studied on the maintenance-supporting applications for inspectors previously. The advantage of pre-existing marker system is that the making and using are easier than any other feature tracking and detection methods. However it must to be exposed to the sufficient light to be detected by computer image processing. The most of industry field is not in clean environment and there are not sufficient light as well. So, the normal marker system is not appropriated for industrial fields. This paper suggests RFID-based marker system to improve marker-detection ability in our AR maintenance system. RFID is not implemented by image processing but it is implemented by electromagnetic induction. Therefore we could more precisely detect markers even if the environment is low-light intensity condition.

• Journal of Korea Multimedia Society
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• v.22 no.10
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• pp.1142-1148
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• 2019

Reconstruction of the three-dimensional (3D) environment is a key aspect of augmented reality and augmented virtuality, which utilize and incorporate a user's surroundings. Such reconstruction can be easily realized by employing a Kinect device. However, multiple Kinect devices are required for enhancing the reconstruction density and for spatial expansion. While employing multiple Kinect devices, they must be calibrated with respect to each other in advance, and a marker is often used for this purpose. However, a marker needs to be placed at each calibration, and the result of marker detection significantly affects the calibration accuracy. Therefore, a user-friendly, efficient, accurate, and marker-less method for calibrating multiple Kinect devices is proposed in this study. The proposed method includes a joint tracking algorithm for approximate calibration, and the obtained result is further refined by applying the iterative closest point algorithm. Experimental results indicate that the proposed method is a convenient alternative to conventional marker-based methods for calibrating multiple Kinect devices. Hence, the proposed method can be incorporated in various applications of augmented reality and augmented virtuality that require 3D environment reconstruction by employing multiple Kinect devices.

• Proceedings of the Korean Institute of Information and Commucation Sciences Conference
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• 2011.05a
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• pp.69-72
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• 2011

In this paper, we propose a method to track the movement of camera from the video sequences. This method is useful for video analysis and can be applied as pre-processing step in some application such as video stabilizer and marker-less augmented reality. First, we extract the features in each frame using corner point detection. The features in current frame are then compared with the features in the adjacent frames to calculate the optical flow which represents the relative movement of the camera. The optical flow is then analyzed to obtain camera movement parameter. The final step is camera movement estimation and correction to increase the accuracy. The method performance is verified by generating a 3D map of camera movement and embedding 3D object to the video. The demonstrated examples in this paper show that this method has a high accuracy and rarely produce any jitter.

• Proceedings of the ESK Conference
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• 1996.10a
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• pp.160-165
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• 1996

This paper presents the development of video-based 3-dimensional tracking system. Measurement of human motion is important in the application of ergonomics. The system uses advanced direct video measurement technology. Passive retro-reflecting markers are attached to a subject and movements of markers are observed by two CCD cameras. Infrared light emitted near the CCD cameras is reflected by the markers and is detected by the cameras. The image ae captured by Samsung MVBO2 board and the center of markers is calculated by DSP program. The position of markers are transferred from MVB02 board to the computer through AT bus. The computer then tracks the position of each marker and saves the data. This system has dynamic accuracy with 1% error and the sampling rate to 6-10 Hz, and can analyse the trajectory and speed of the marker. The results of this study can be used for operators motion analysis, task analysis, and hand movement characteristic analysis.

• Journal of Drive and Control
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• v.17 no.4
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• pp.8-14
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• 2020

Intelligent devices using ICT technology have been introduced in the field of construction machinery to improve productivity and stability. Among the intelligent devices, Machine Guidance is a device that provides real-time posture, location, and work range to drivers by installing various sensors, controllers, and satellite navigation systems on construction machines. Conversely, the efficiency of equipment that requires location information, such as machine guidance, will be greatly reduced in buildings, and tunnels in the GPS blind spots. Thus, the other high-precision positioning technologies are required in the GPS blind spot zone. In this study, we will develop a relative position measurement system that provides precise location information such as construction machinery and robots in a local area where the GPS reception is difficult. A relative position measurement system tracks a marker in the form of a sphere installed on a vehicle by using the image base tracking technology, and measures the distance and direction information to the marker to calculate a position.