• Korean Journal of Computational Design and Engineering
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• v.16 no.4
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• pp.277-284
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• 2011

In tangible augmented reality (AR) environments for virtual prototyping, the user interacts with virtual products by manipulating tangible objects with his or her hands, but the user often encounter awkward situations in which his or her hands are occluded by augmented virtual objects, which reduces both immersion and ease of interaction. In this paper, we present how to resolve such hand region occlusion in order to enhance natural interaction and immersive visualization. In the AR environment considered, we use two types (product-type and pointer-type) of tangible objects for tangible user interaction with a virtual product of interest. Holding the tangible objects with his or her hands, the user can create input events by touching specified regions of the product-type tangible object with the pointer-type tangible object. We developed a method for resolving hand region occlusion frequently arising during such user interaction, It first detect hand region in a real image and refines the rendered image of the virtual object by subtracting the hand region from the rendered image, Then, it superimposes the refined image onto the real image to obtain an image in which the occlusion is resolved. Incorporated into tangible AR interaction for virtual prototyping of handheld products such as cellular phones and MP3 players, the method has been found by a preliminary user study that it is not only useful to improve natural interaction and immersive visualization of virtual products, but also helpful for making the users experience the products' shapes and functions better.

• Journal of the Korea Computer Graphics Society
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• v.9 no.1
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• pp.19-27
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• 2003

Most interaction schemes in virtual environment are indirect in one way or another. ln particular, without a haptic device (which introduces its own problems due to its cumbersomeness), users must rely on visual (or/and aural) feedback, and can not directly appreciate the 3Dness of the interaction object even with stereoscopy. This causes a drop in object presence because people are used to, for instance, observing objects in one's hand, rotating and manipulating them with physical contact. To alleviate this problem, this paper proposes a hand-held cubic screen, named TangibleScreen, on which the appearance of the target interaction object is projected. We choose the Relief Texture Mapping as the rendering method to correctly generate the viewer dependent textures to be projected on the non-planar surfaces of the TangibleScreen.

• Korean Journal of Computational Design and Engineering
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• v.16 no.1
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• pp.1-10
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• 2011

In this paper, we propose an AR-based tangible interaction using a finger fixture for virtual evaluation of digital handheld products. To realize tangible interaction between a user and a product in a computer-vision based AR environment, we uses two types of tangible objects: a product-type object and a finger fixture. The product-type object is used to acquire the position and orientation of the product, and the finger fixture is used to recognize the position of a finger tip. The two objects are fabricated by RP technology and AR markers are attached to them. The finger fixture is designed to satisfy various requirements with an ultimate goal that the user holding the finger fixture in his or her index finger can create HMI events by touching specified regions (buttons or sliders) of the product-type object with the finger tip. By assessing the accuracy of the proposed interaction, we have found that it can be applied to a wide variety of digital handheld products whose button size is not less than 6 mm. After performing the design evaluation of several handheld products using the proposed AR-based tangible interaction, we received highly encouraging feedback from users since the proposed interaction is intuitive and tangible enough to provide a feeling like manipulating products with human hands.

• Korean Journal of Computational Design and Engineering
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• v.17 no.6
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• pp.417-425
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• 2012

In recent years, great attention has been paid to using simple physical objects as tangible objects to improve user interaction in augmented reality (AR) environments. In this paper, we address AR-based user interaction using tangible objects, which has been used as a key component for virtual design evaluation of engineered products including digital handheld products. We herein consider the use of two types (product-type and pointer-type) of tangible objects. The user creates input events by touching specified parts of the product-type object with the pointer-type object, and the virtual product reacts to the events by rendering its visual and auditory contents on the output devices. The product-type object is used to reflect the geometric shape of a product of interest and to determine its position and orientation in the AR environment. The pointer-type object is used to recognize the reference position of the pointer (or finger) in the same environment. The rapid prototype of the product is employed as a good alternative to the product-type object, but various alternatives to the pointer-type object can be considered according to fabrication process and touching mechanism. In this paper, we present four alternatives to the pointer-type object and investigate their strong and weak points by performing experimental comparison of their various aspects including interaction accuracy, task performance, and qualitative user experience.

• Korean Journal of Computational Design and Engineering
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• v.13 no.3
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• pp.209-216
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• 2008

This paper presents a novel approach to design evaluation of portable consumer electronic (PCE) products using augmented reality (AR) based tangible interaction and functional behavior simulation. In the approach, the realistic visualization is acquired by overlaying the rendered image of a PCE product on the real world environment in real-time using computer vision based augmented reality. For tangible user interaction in an AR environment, the user creates input events by touching specified regions of the product-type tangible object with the pointer-type tangible object. For functional behavior simulation, we adopt state transition methodology to capture the functional behavior of the product into a markup language-based information model, and build a finite state machine (FSM) to controls the transition between states of the product based on the information model. The FSM is combined with AR-based tangible objects whose operation in the AR environment facilitates the realistic visualization and functional simulation of the product, and thus realizes faster product design and development. Based on the proposed approach, a product design evaluation system has been developed and applied for the design evaluation of various PCE products with highly encouraging feedbacks from users.

• 제어로봇시스템학회:학술대회논문집
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• 2004.08a
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• pp.1093-1097
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• 2004

We propose 'the haptic primitive' for haptic rendering without the need to solve complicated parametric equations. To develop 'the haptic primitive', we adopted "the God-Object Method" as a haptic rendering algorithm and applied 'Constructive Solid Geometry' to manage haptic objects. Besides being used in the 'ghost library' of $PHANToMTM^{TM}$ our method can be used as a basic component for developing tools and libraries that aim to simplify haptic modeling. It can also be applied to tactile display modules and temporal display modules. Ultimately it can be developed into a one-stop haptic modeling tool that enables the user to more conveniently create a tangible CAD systems or a tangible e-ommerce system.

• 한국HCI학회:학술대회논문집
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• 2007.02b
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• pp.264-269
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• 2007

본 논문에서는 감각형 객체(Tangible Object)를 이용한 테이블에서의 2D/3D 상호작용 시스템을 제안한다. 제안된 시스템은 기존의 ARTable[1]에 직육면체 형태의 감각형 객체와 카메라가 장착된 이동형 모니터를 추가하여 제작되었다. 감각형 객체는 모든 면에 ARToolkit[3]에서 쓰이는 마커가 부착되어 있으며, 내부에는 진동자와 불루투스 통신 모듈이 삽입되어 있다. 또한 카메라가 달린 모니터는 모니터 암에 연결되어 사용자가 이동하며 ARTable 상판을 관측할 수 있도록 부착되어 있다. 이 시스템를 이용하여 사용자는 디스플레이형 테이블인 ARTable 위에서 가상공간을 네비게이션(2D 상호작용)할 때 정확한 길을 찾아가기 위한 도움을 받을 수 있을 뿐만 아니라, 증강현실 환경에서 가상객체와 3D 상호작용을 할 수 있다. 또한 진동 모듈과 이를 제어하기 위한 블루투스 모듈이 내장 되어있어, 특정한 이벤트 발생시 진동자를 이용하여 사용자에게 촉각 감응 효과를 줄 수 있다. 제안된 시스템은 교육, 엔터테이먼트, 등 다양한 분야에서 사용될 수 있다.

• Journal of the Institute of Electronics Engineers of Korea CI
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• v.49 no.4
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• pp.71-81
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• 2012

In order to support simple authoring an application of augmented reality for diverse users, the process for the object registration comprised of tracking and recognizing the object should be accomplished intuitively and simple. Although many 3D reconstruction methods to be applied to the object registration have been developed, the methods have not beyond the experimental level yet. In this paper, we proposed a novel marker-based tangible interfaces for various users to manipulate the object with intuitive and simple approaches during an authoring applications fo augmented reality. The proposed method make use of marker as intuitive interface to obtain 3D geometric information of 3D reconstruction. 3D geometric information of an object surface is acquired by touching the object directly with the proposed tangible interfaces. The tangible interfaces not only support 3D reconstruction for graphical modeling but also offer features information which is used for augmented reality. Finally, we verify efficiency of the proposed method with demonstration of an augmented reality application using the proposed method.

• 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.

• Journal of KIISE:Software and Applications
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• v.31 no.10
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• pp.1356-1363
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• 2004

We propose Tangible Media Control System (TMCS), which allows users to manipulate media contents with physical objects in an intuitive way. Currently, most people access digital media contents by exploiting GUI. However, It provides limited manipulations of the media contents. The proposed system, instead of mouse and keyboard, adopts two types of tangible objects, i.e RFID-enabled object and tracker-embedded object. The TMCS enables users to easily access and control digital media contents with the tangible objects. In addition, it supports an interactive media controller which users can synthesize media contents and generate new media contents according to users' taste. It also offers personalized contents, which is suitable for users' preferences, by exploiting context such as user's profile and situational information. Therefore. the proposed system can be applied to various interactive applications such as multimedia education, entertainment and multimedia editor.