• 대한기계학회논문집A
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• 제29권2호
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• pp.176-187
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• 2005

This paper presents an evaluation of joint configurations of a robotic finger based on kinematic analysis. The evaluation is based on an assumption that the current control methods for the fingers require that the contact state specified by the motion planner be maintained during manipulation. Various finger-joint configurations have been evaluated for different contact motions. In the kinematic analysis, the surface of the manipulated object was represented by B-spline surface and the surface of the finger was represented by cylinders and a half ellipsoid. Three types of contact motion, namely, 1) pure rolling, 2) twist-roiling, and 3) slide-twist-rolling are assumed in this analysis. The finger-joint configuration best suited for manipulative motion is determined by the dimension of manipulation workspace. The evaluation has shown that the human-like fingers are suitable for maintaining twist-rolling and slide-twist-rolling but not for pure rolling. A finger with roll joint at its fingertip link, which is different from human fingers, proved to be better for pure rolling motion because it can accommodate sideway motions of the object. Several kinds of useful finger-joint configurations suited for manipulating objects by fingertip surface are proposed.

• 한국정밀공학회지
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• 제16권1호통권94호
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• pp.42-48
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• 1999

A control method for a robot hand grasping a object in a partially unknown environment will be proposed, where a proximate sensor detecting the distance between the fingertip and object was used. Particularly, the finger joints were driven servo-pneumatically in this study. Based on the proximate sensor signal the finger motion controller could plan the grasping process divided in three phases ; fast aproach, slow transitional contact and contact force control. That is, the fingertip approached to the object with full speed, until the output signal of the proximate sensor began to change. Within the perating range of the proximate sensor, the finger joint was moved by a state-variable feedback position controller in order to obtain a smooth contact with the object. The contact force of fingertip was then controlled using the blocked-line pressure sensitivity of the flow control servovalve for finger joint control. In this way, the grasping impact could be reduced without reducing the object approaching speed. The performance of the proposed grasping method was experimentally compared with that of a open loop-controlled one.

• 한국CDE학회논문집
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• 제18권5호
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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.

• 한국방송∙미디어공학회:학술대회논문집
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• 한국방송공학회 2009년도 IWAIT
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• pp.290-293
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• 2009

In this paper, we propose a method to estimate pointing region in real-world from images of cameras. In general, arm-pointing gesture encodes a direction which extends from user's fingertip to target point. In the proposed work, we assume that the pointing ray can be approximated to a straight line which passes through user's face and fingertip. Therefore, the proposed method extracts two end points for the estimation of pointing direction; one from the user's face and another from the user's fingertip region. Then, the pointing direction and its target region are estimated based on the 2D-3D projective mapping between camera images and real-world scene. In order to demonstrate an application of the proposed method, we constructed an ICGS (interactive cinema guiding system) which employs two CCD cameras and a monitor. The accuracy and robustness of the proposed method are also verified on the experimental results of several real video sequences.

• Archives of Plastic Surgery
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• 제39권4호
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• pp.404-410
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• 2012

Background First suggested by Brent in 1979, the pocket principle is an alternative method for patients for whom a microsurgical replantation is not feasible. We report the successful results of a modified palmar pocket method in adults. Methods Between 2004 and 2008, we treated 10 patients by nonmicrosurgical replantation using palmar pocketing. All patients were adults who sustained a complete fingertip amputation from the tip to lunula in a digits. In all of these patients, the amputation occurred due to a crush or avulsion-type injury, and a microsurgical replantation was not feasible. We used the palmar pocketing method following a composite graft in these patients and prepared the pocket in the subcutaneous layer of the ipsilateral palm. Results Of a total of 10 cases, nine had complete survival of the replantation and one had 20% partial necrosis. All of the cases were managed to conserve the fingernails, which led to acceptable cosmetic results. Conclusions A composite graft and palmar pocketing in adult cases of fingertip injury constitute a simple, reliable operation for digital amputation extending from the tip to the lunula. These methods had satisfactory results.

• 한국컴퓨터정보학회논문지
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• 제19권2호
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• pp.125-132
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• 2014

본 논문에서는 저가의 웹 카메라를 사용하여 마커 없이 손끝과 붓을 트래킹 하는 시스템을 제시한다. 트래킹 시스템은 CUDA를 사용하여 병렬처리를 적용했다. 이 트래킹 시스템은 노트북이나 데스크탑과 같은 환경에서 수행이 가능하고, 실시간 애플리케이션에 사용 가능한 성능을 가진다. 또한 본 논문에서는 사적인 수성 사인펜 드로잉 모델을 제시하고 구현된 결과를 보여준다. 제안하는 시스템은 손끝과 붓을 트래킹 하는 저가의 실시간 트래킹 시스템으로 사실적 드로잉 애플리케이션과 연동하여 미래 최첨단 교육 환경 구축의 테스트베드로의 활용을 기대한다.

• Archives of Plastic Surgery
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• 제39권4호
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• pp.411-411
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• 2012

• Archives of Reconstructive Microsurgery
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• 제21권1호
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• pp.27-33
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• 2012

We studied the results of the immediate microsurgical reconstruction of the distal digit injury with short vascular pedicled partial toe transfer. Thirteen patients with amputation or crush injury of the distal digit who underwent partial toe transfer at the authors' institute over 8-year period were reviewed. Delay between initial injury and reconstruction ranged from 1 to 9 days. All flaps were harvested on a short vascular pedicle, with anastomoses performed at a proximal interphalangeal joint level on the fingers and metacarpophalangeal joint level on the thumbs. Good to excellent cosmetic and functional results were obtained in all cases, with nearly normal-looking fingertip. The mean static two point discrimination was 10 mm. Immediate reconstruction with short vascular pedicled partial toe transfer is an excellent option for the reconstruction of the compostie defect of the distal digit.

• International Journal of Contents
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• 제6권4호
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• pp.49-56
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• 2010

In this paper we present a system that enables the user to interact with large display system even without touching the screen. With two infrared sensitive cameras mounted on the bottom left and bottom right of the display system pointing upwards, the user fingertip position on the selected region of interest of each camera view is found using vertical intensity profile of the background subtracted image. The position of the finger in two images of left and right camera is mapped to the display screen coordinate by using pre-determined matrices, which are calculated by interpolating samples of user finger position on the images taken by pointing finger over some known coordinate position of the display system. The screen is then manipulated according to the calculated position and depth of the fingertip with respect to the display system. Experimental results demonstrate an efficient, robust and stable human computer interaction.

• 대한전기학회논문지
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• 제40권8호
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• pp.825-835
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• 1991

This paper deals with a case for robotic hands to grasp the objects using inner link contact as well as fingertip contact. And the case is proved to be more efficient than the case of using only fingertip contact in terms of stability and uniform distribution of the contact forces. The general algorithm for the determination of the optimal ocntact force is developed for the soft finger contact as well as the point contact with friction. To show the validity of the proposed algorithm a numerical example is illustated by employing a robotic hand with three fingers each of which has four joints.