• Proceedings of the IEEK Conference
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• 2007.07a
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• pp.353-354
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• 2007

This paper proposes the method which estimates the pointing region at the real world. This paper uses the technique to easily calibrate a camera of Z. Zhang. First, we calculate the projection matrix of each camera by the technique. Next, we estimate the location of the shoulder and the fingertip. Then we compute the pointing region in 3D real world by using projection matrix of each camera. Experiment result showed that the error between estimated point and the plane center point is less than 5cm.

• Journal of Korea Multimedia Society
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• v.12 no.12
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• pp.1761-1768
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• 2009

In this paper, we implemented online real time strategy game using hand as the mouse in augmented reality. Also, we introduced the algorithm for detecting hand direction, finding fingertip of the index finger and counting the number of fingers for interaction between users and the virtual objects. The proposed method increases the reality of the game by combining the real world and the virtual objects. Retinex algorithm is used to remove the effect of illumination change. The implementation of the virtual reality in the online environment enables to extend the applicability of the proposed method to the areas such as online education, remote medical treatment, and mobile interactive games.

• Journal of Information Processing Systems
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• v.17 no.3
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• pp.505-517
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• 2021

This research presented an implementation of autostereoscopic virtual three-dimensional (3D) button device as non-contact style. The proposed device has several characteristics about visible feature, non-contact use and artificial intelligence (AI) engine. The device was designed to be contactless to prevent virus contamination and consists of 3D buttons in a virtual stereoscopic view. To specify the button pressed virtually by fingertip pointing, a simple deep learning network having two stages without convolution filters was designed. As confirmed in the experiment, if the input data composition is clearly designed, the deep learning network does not need to be configured so complexly. As the results of testing and evaluation by the certification institute, the proposed button device shows high reliability and stability.

• Journal of the Korean Society for Precision Engineering
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• v.13 no.9
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• pp.94-103
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• 1996

This paper is concerned with the theroretical and experimental study on the force control of a miniature robotic finger that grasps an object at three other positions with the fingertip. The artificial finger is uniform flexible cantilever beam equipped with a distributed set of compact grasping force secnsors. Control action is applied by a qiexoceramic bimorph strip placed at the base of the finger. The mathematical model of the assembled electro-mechanical system is developed. The distributed sensors are described by a set of concentrated mass-spring system. The formulated equations of motion are then applied to a control problem which the finger is commanded to grasp an object The PID-controller is introduced to drive the finger. The usefulness of the proposed control technique is verified by simulation and experiment.

• Journal of the Korean Society for Precision Engineering
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• v.13 no.8
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• pp.128-138
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• 1996

Based on the virtual stiffness model, the stiffness of a grasped object is characterized. Differing from the previous investigations, the effect of grasp force on the stiffness of a grasp is formulated in terms of additional stiffness, which is called additional stiffness in this paper, and it is addressed how this term affects the stability of a grasp. In addition, a method of controlling the stiffness of a grasp is proposed and validated by experiments using a two-fingered robot hand.

• ETRI Journal
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• v.46 no.2
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• pp.250-262
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• 2024

Air-writing recognition is relevant in areas such as natural human-computer interaction, augmented reality, and virtual reality. A trajectory is the most natural way to represent air writing. We analyze the recognition accuracy of words written in air considering five features, namely, writing direction, curvature, trajectory, orthocenter, and ellipsoid, as well as different parameters of a hidden Markov model classifier. Experiments were performed on two representative datasets, whose sample trajectories were collected using a Leap Motion Controller from a fingertip performing air writing. Dataset D₁ contains 840 English words from 21 classes, and dataset D₂ contains 1600 English words from 40 classes. A genetic algorithm was combined with a hidden Markov model classifier to obtain the best subset of features. Combination ftrajectory, orthocenter, writing direction, curvatureg provided the best feature set, achieving recognition accuracies on datasets D₁ and D₂ of 98.81% and 83.58%, respectively.

• Journal of Korea Multimedia Society
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• v.16 no.2
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• pp.138-146
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• 2013

In this paper, we propose a new 3D PUI(Physical User Interface) system in which the index fingertip points and moves a mouse position on a given monitor screen. There are two 3D PUI schemes to control smart devices like smart TVs remotely, the relative pointing one and the absolute pointing one. The former has a problem in that it does not match the human perception process, and the latter requires excessive movement of the body. We combined the relative one and the absolute one, and develop a new intuitive and user-friendly pointing method, 3D PUI. It requires an establishment of a pyramid shape visible area (view volume) to point a mouse position on a screen with the dominant eye. In order to maintain the real-time view volume, however, it requires large computation depending on the movement of the dominant eye. We optimized the computation of the view volume in which it determines the internal and external position on the screen. In addition, Kalman filter is applied with tracing of the mouse pointer position to stabilize the trembling of the pointer and offers the user ease of use.

• Journal of the Ergonomics Society of Korea
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• v.26 no.1
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• pp.11-18
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• 2007

The physiological and biochemical responses of healthy men and women to life stress were measured in order to temperature, blood pressure (BP), heart rate (HR) and galvanic skin response (GSR) were selected as physiological stress indices and salivary cortisol level was used as a biochemical stres biomarker. Twenty six (male 14 and female 13) colege students were participated in the experiment. Female showed the significant higher value of salivary cortisol level (p<0.01), diastolic BP (p<0.01), and HR (p<0.01) than male. The difference of skin temperature between forehead and fingertip correlated significantly with salivary cortisol level (p<0.01). The LF(low frequency)/HF(high frequency) ratio of HRV also correlated significantly with salivary cortisol level (p<0.01). However, BP, HR and GSR corelated insignificantly with salivary cortisol level. We suggest that LF/HF ratio of HRV and skin temperature may be good indices for the assessment of life stress, and may apply to measure the stress level of individual in real time.

• Transactions of the Korean Society of Mechanical Engineers A
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• v.29 no.2 s.233
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• pp.188-200
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• 2005

Control of a multi-fingered robotic hand is usually based on the theoretical analysis for kinematics and dynamics of fingers and of object. However, the implementation of such analyses to robotic hands is difficult because of errors and uncertainties in the real situations. This article presents the control method for estimating the kinematic constraint of an unknown object by active sensing. The experimental system has a two-fingered robotic hand suspended vertically for manipulation in the vertical plane. The fingers with three degrees-of-freedom are driven by wires directly connected to voice-coil motors without reduction gears. The fingers are equipped with three-axis force sensors and with dynamic tactile sensors that detect slippage between the fingertip surfaces and the object. In order to make an accurate estimation for the kinematic constraint of the unknown object, i.e. the constraint direction and the constraint center, four kinds of the active sensing and feedback control algorithm were developed: two position-based algorithms and two force-based algorithms. Furthermore, the compound and effective algorithm was also developed by combining two algorithms. Force sensors are mainly used to adapt errors and uncertainties encountered during the constraint estimation. Several experimental results involving the motion of lifting a finger off an unknown object are presented.

• Journal of Life Science
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• v.13 no.1
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• pp.42-46
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• 2003

Photoplethysmogram is widely used to measure heart rate and arterial blood oxygen saturation in human. This paper describes radial pulse waves recorded by photoplethysmogram with 940 nm wavelength infra red light. Radial pulse waves were varied according to the recording site. When recorded on the skin over radial artery, the radial pulse wave was inverted, comparing to the photoplethysmogram at fingertip. The mechanism of inverted pulse wave seemed to be caused by the change of the blood volume in the subcutaneous tissue between radial artery and the skin, which was reduced during systolic period and increased during diastolic period of the cardiac cycle. These results suggest that radial arterial wall may reflect infra red ray.