• KSII Transactions on Internet and Information Systems (TIIS)
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• v.4 no.4
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• pp.618-632
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• 2010

This paper presents a novel approach to control the augmented reality (AR) objects robustly in a marker-less AR system by fingertip tracking and hand pattern recognition. It is known that one of the promising ways to develop a marker-less AR system is using human's body such as hand or face for replacing traditional fiducial markers. This paper introduces a real-time method to manipulate the overlaid virtual objects dynamically in a marker-less AR system using both hands with a single camera. The left bare hand is considered as a virtual marker in the marker-less AR system and the right hand is used as a hand mouse. To build the marker-less system, we utilize a skin-color model for hand shape detection and curvature-based fingertip detection from an input video image. Using the detected fingertips the camera pose are estimated to overlay virtual objects on the hand coordinate system. In order to manipulate the virtual objects rendered on the marker-less AR system dynamically, a vision-based hand control interface, which exploits the fingertip tracking for the movement of the objects and pattern matching for the hand command initiation, is developed. From the experiments, we can prove that the proposed and developed system can control the objects dynamically in a convenient fashion.

• Proceedings of the Korean Institute of Information and Commucation Sciences Conference
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• 2017.05a
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• pp.297-299
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• 2017

Recently, the application fields of augmented reality(AR) are rapidly increasing, and related contents are also increasing in demand. In this way, object-based marker recognition is required for service of AR contents in mobile environment. At this time, in order to provide information corresponding to the marker, a technique of generating and servicing a virtual object corresponding to a specific marker is used. However, when a virtual object corresponding to a marker is held on the AR screen, a phenomenon occurs that an object of the marker unstably shakes due to various reasons such as camera shake and camera movement. As described above, the AR service based on the mobile device has a problem that it is difficult to represent objects stably. In this paper, we propose a stable marker recognition and tracking technique by applying the filtering technique according to the physical state change of the device when recognizing fixed markers in mobile AR environment.

• Journal of information and communication convergence engineering
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• v.20 no.1
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• pp.65-72
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• 2022

With the mark of the fourth industrial revolution, the smart factory is evolving into a new future manufacturing plant. As a human-machine-interactive tool, augmented reality (AR) helps workers acquire the proficiency needed in smart factories. The valuable data displayed on the AR device must be delivered intuitively to users. Current AR applications used in smart factories lack user movement calibration, and visual fiducial markers for position correction are detected only nearby. This paper demonstrates a marker-based object detection using perspective projection to adjust augmented content while maintaining the user's original perspective with displacement. A new angle, location, and scaling values for the AR content can be calculated by comparing equivalent marker positions in two images. Two experiments were conducted to verify the implementation of the algorithm and its practicality in the smart factory. The markers were well-detected in both experiments, and the applicability in smart factories was verified by presenting appropriate displacement values for AR contents according to various movements.

• Korean Journal of Computational Design and Engineering
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• v.18 no.5
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• pp.374-383
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• 2013

Various interaction techniques have been studied for providing the feeling of touch and improve immersion in augmented reality (AR) environments. Tangible AR interaction exploiting two types (product-type and pointer-type) of simple objects has earned great interest for cost-effective design evaluation of digital handheld products. When the sizes of markers attached to the objects are kept big to obtain better marker recognition, the pointer-type object frequently and significantly occludes the product-type object, which deteriorates natural visualization and level of immersion in an AR environment. In this paper, in order to overcome such problems, we propose tangible AR interaction using fingertip touch combined with small-sized markers. The proposed approach facilitates the use of convex polygons to recover the boundaries of AR markers which are partially occluded. It also properly enlarges the pattern area of each AR marker to reduce the sizes of AR markers without sacrificing the quality of marker detection. We empirically verified the quality of the proposed approach, and applied it in the process of design evaluation of digital products. From experimental results, we found that the approach is comparably accurate enough to be applied to the design evaluation process and tangible enough to provide a pseudo feeling of manipulating virtual products with human hands.

• Proceedings of the Korean Institute of Information and Commucation Sciences Conference
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• 2017.05a
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• pp.288-290
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• 2017

Recently, interest and demand of Augmented Reality(AR) contents are increasing as an application field of AR. Generally, when the AR contents are served in the outdoor environment, the position information using the GPS signal is used to control the display of the object on the AR screen, or a marker based on the image of the object is used. However, there is a problem that location information can not be used in an indoor environment. If the service is provided using only the marker, there is a problem that the recognition of the marker due to the moving obstacle in the vicinity is unstable. and there is a problem that information displayed on the AR screen is not displayed in a fixed state at a specific position, it moves according to the movement of the camera. In this paper, we have studied the object control method for displaying the object to be displayed on the AR screen by using iBeacon using indoor location recognition and specific markers.

• Korean Journal of Artificial Intelligence
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• v.12 no.3
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• pp.9-15
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• 2024

This paper addresses the critical need for quadcopters in GPS-denied indoor environments by proposing a novel attitude control mechanism that enables autonomous navigation without external guidance. Utilizing AR marker detection integrated with a dual PID controller algorithm, this system ensures accurate maneuvering and positioning of the quadcopter by compensating for the absence of GPS, a common limitation in indoor settings. This capability is paramount in environments where traditional navigation aids are ineffective, necessitating the use of quadcopters equipped with advanced sensors and control systems. The actual position and location of the quadcopter is achieved by AR marker detection technique with the image processing system. Moreover, in order to enhance the reliability of the attitude PID control, the dual closed loop control feedback PID control with dual update periods is suggested. With AR marker detection technique and autonomous attitude control, the proposed quadcopter system decreases the need of additional sensor and manual manipulation. The experimental results are demonstrated that the quadrotor's autonomous attitude control and operation with the dual closed loop control feedback PID controller with hierarchical (inner-loop and outer-loop) command update period is successfully performed under the non-GPS aided indoor environment and it enhanced the reliability of the attitude and the position PID controllers within 17 seconds. Therefore, it is concluded that the proposed attitude control mechanism is very suitable to GPS-denied indoor environments, which enables a quadcopter to autonomously navigate and hover without external guidance or control.

• Journal of Korea Multimedia Society
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• v.24 no.6
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• pp.753-759
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• 2021

During tensile test, tensile strain of tensile tester is measured by movement distance of upper zig and initial specimen's length. Conventional tensile tester program obtains the tensile strain after the end of the test, however the method is not appropriate in real time because the results are calculated until the test is finished. We suggest a real-time measurement system of tensile strain using ArUco Marker in OpenCV library. The system is designed to detect marker attached on the upper zig and calculate specimen's tensile strain. According to comparison of the calculated data and the results of the tester, errors approximately showed 0.128 mm on 3840×2160 video resolution.

• Korean Journal of Computational Design and Engineering
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• v.16 no.5
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• pp.361-369
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• 2011

As smartphones came into wide use recently, it has become increasingly popular not only among young people, but middle-aged people as well. Most smartphones use capacitive full touch screen, so touch commands are made by fingers unlike the PDAs in the past that use touch pens. In this case, a significant portion of the smartphone's screen is blocked by the finger so it is impossible to see the screens around the finger touching the screen, and difficulty occurs in precise control used for small buttons such as qwerty keyboard. To solve this problem, this research proposes a method of using simple AR markers to improve the interface of smartphones. Sticker-form marker is attached to fingernails and placed in front of the smartphone camera Then, the camera image of the marker is analyzed to determine the orientation of the marker to perceive as onRelease() or onPress() of the mouse depending on the marker's angle of rotation, and use its position as the position of the mouse cursor. This method can enable click, double-click, drag-and-drop used in PCs as well as touch, slide, long-touch-input in smartphones. Through this research, smartphone inputs can be made more precise and simple, and show the possibility of the application of a new concept of smartphone interface.

• Journal of Convergence for Information Technology
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• v.12 no.1
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• pp.1-6
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• 2022

As augmented reality technology becomes more common and prevelant, marker-based AR contents are applied in various ways. However AR contents are still hardly utilized due to the low recognition rate of marker images. In order to increase the recognition rate of AR marker images, this paper experiment and analyzed how much the recognition rate of markers could be improved when image correction and design changes was applied. The experimental result shows that the image correction task could significantly improve the number of image characteristics and the recognition grade if the image was modified in a way its saturation value is increased. Moreover, the recognition rate was improved even more when regular pattern design was added to the original marker image. In conclusion, it was possible to make the marker well recognized through proper correction of the image and additional process of pattern design in the process of producing the marker image.

• ETRI Journal
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• v.35 no.6
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• pp.1048-1057
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• 2013

In recent years, augmented reality (AR) technologies have been the subject of great interest among many communities. In education applications, old-fashioned materials (or textbooks) are still used, despite remarkable AR developments in the industrial area. We present an AR system for education. Our system consists of an authoring tool that can be used to create educational content, a viewer that plays that content, and an engine to manage the tool and viewer. In our system, a marker unit recognizes a marker printed on a plane or a cubic plane by adaptively adjusting the threshold to have an excellent recognition rate in diverse environments and acquires corresponding data of the marker. Based on the system, we test 142 elementary school students for increased educational benefits using our system.