• Journal of the Korean Society for Aeronautical & Space Sciences
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• v.34 no.5
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• pp.81-87
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• 2006

In this paper, an experimental optical head tracker system is designed and constructed. The system is composed of the infrared LEDs and two infrared CCD cameras to filter out the interference of another light in the limited environment like the cockpit. Then the optical head tracker algorithm is designed by using the feature detection algorithm and the 3D motion estimation algorithm. The feature detection algorithm, used to obtain the 2D position coordinates of the features on the image plane, is implemented by using the thresholding and the masking techniques. The 3D motion estimation algorithm which estimates the motion of a pilot's head is implemented by using the extended Kalman filter (EKF). Also, we used the precise rate table to verify the performance of the experimental optical head tracker system and compared the rotational performance of this system with the inertial sensor.

• Journal of Broadcast Engineering
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• v.19 no.2
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• pp.205-214
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• 2014

Minimization of visual fatigue is important for production of high quality stereoscopic 3D contents. Vertical disparity of stereo images occurred during contents production is considered as the main factor of visual fatigue. To ensure correct stereoscopy vertical disparity needs to be eliminated. In this paper, a method for automated image alignment was proposed for Stereoscopic 3D contents generation and post-processing steps. The proposed method consists of two parts: rectification for image alignment and camera motion detection. The proposed method showed that its rectification performance was the most superior among the existing methods tested and that camera motion detection had a success rate of 98.35%. Through these evaluations, we confirmed that the proposed method can be effectively applied to 3D contents production.

• Korean Journal of Applied Biomechanics
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• v.31 no.3
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• pp.183-188
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• 2021

Objective: The purpose of this study was to develop a stretchable joint motion sensor that is based on silver nano-particle. Through this sensor, it can be utilized as an equipment for rehabilitation and analyze joint movement. Method: In this study, precursor solution was created, after that, nozel printer (Musashi, Image master 350PC) was used to print on a circuit board. Sourcemeter (Keithley, Keithley-2450) was used in order to evaluate changes of electric resistance as the sensor stretches. In addition, the sensor was attached on center of a knee joint to 2 male adults, and performed knee flexion-extension in order to evaluate accurate analysis; 3 infrared cameras (100 Hz, Motion Master 100, Visol Inc., Korea) were also used to analyze three dimensional movement. Descriptive statistics were suggested for comparing each accuracy of measurement variables of joint motions with the sensor and 3D motions. Results: The change of electric resistance of the sensor indicated multiple of 30 times from initial value in 50% of elongation and the value of electric resistance were distinctively classified by following 10%, 20%, 30%, 40% of elongation respectively. Through using the sensor and 3D camera to analyze movement variable, it showed a resistance of 99% in a knee joint extension, whereas, it indicated about 80% in flexion phase. Conclusion: In this research, the stretchable joint motion sensor was created based on silver nanoparticle that has high conductivity. If the sensor stretches, the distance between nanoparticles recede which lead gradual disconnection of an electric circuit and to have increment of electric resistance. Through evaluating angle of knee joints with observation of sensor's electric resistance, it showed similar a result and propensity from 3D motion analysis. However, unstable electric resistance of the stretchable sensor was observed when it stretches to maximum length, or went through numerous joint movements. Therefore, the sensor need complement that requires stability when it comes to measuring motions in any condition.

• Korean Journal of Applied Biomechanics
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• v.13 no.2
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• pp.89-100
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• 2003

In this research was to analyze 3-D kinematics variables for handspring of basic motion in the heavy gymnastics in order to investigate kinematical difference between expert and novice. Therefore, the purpose of this research was provide quantitative information, systematic provision, rules, establishment of basic skill for improving skill and teaching athletes. And in the research, results were as followings. 1. In the time variables, total time was that expert took 0.745sec and novice took 0.829sec, and as duration time of each event, expert was faster than novice in the all motion event except till second event of the preparation motion. 2. In the center of body variables, vertical direction variables, the displacement of body center hight was that expert showed 61.26% and novice showed 54.48% in the third event of all motion, also all event were showed expert was higher displacement than novice except first of event in preparatory stage. 3. In the angle displacement of main joint, the right direction was that expert showed 154.12degree and novice showed 174.85degree and the left direction was that expert showed 159.29degree and novice showed 171.46degree In the second event of main joint curved point at the same time hand was reached floor. In the angle displacement of knee joint in the third event of all motion, expert showed 155.25degree and novice showed 154.00degree In right, and expert showed 155.24degree and novice showed 154.55degree in left. In this result, both were same motion type. In the angle displacement of hip joint in the third event of the all motion, expert showed 142.80degree and novice showed 134.17degree in right, and expert showed 140.28degree and novice showed 144.94degree in left. In this result, motion pattern of expert was same both sides, but novice was different. According to the results, to increase efficiency of motion and aesthetic effect in the all motion, it should stretch displacement and height of body center and make similarly angle of right and left joint.

• Journal of Information Processing Systems
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• v.2 no.1
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• pp.18-22
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• 2006

This paper proposes the framework of the scenario-based 3D image synthesizing system that allows common users who envision a scenario in their mind to realize it into the segments of cool animation. We focused on utilization of the existing motions to synthesize new motions for the objects. The framework is useful to build a 3D animation in game programming with a limited set of 3D objects. We also propose a practical algorithm to reuse and expand the objects. This algorithm is based on motion path modification rules. Both linear and nonlinear curve-fitting algorithms were applied to modify an animation by key frame interpolation and to make the motion appear realistic.

• Journal of the Institute of Electronics Engineers of Korea SD
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• v.46 no.2
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• pp.85-92
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• 2009

This paper proposes a full-search block-matching motion estimation circuit with hybrid architecture combining systolic arrays and adder trees for an MPEG-4 encoder. The proposed circuit uses systolic arrays for motion estimation with a small number of clock cycles and adder trees to reduce required circuit resources. The interpolation circuit for 1/2 pixel motion estimation consists of six adders, four subtracters and ten registers. We improved the circuit performance by resource sharing and efficient scheduling techniques. We described the motion estimation circuit for integer and 1/2 pixels at RTL in Verilog HDL. The logic-level circuit synthesized by using 130nm standard cell library contains 218,257 gates and can process 94 D1($720{\times}480$) image frames per second.

• International Journal of Fuzzy Logic and Intelligent Systems
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• v.10 no.3
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• pp.203-209
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• 2010

This paper presents a hierarchical fuzzy motion planner for humanoid robots in 3D uneven environments. First, we define both motion primitives and locomotion primitives of humanoid robots. A high-level planner finds a global path from a global navigation map that is generated based on a combination of 2.5 dimensional maps of the workspace. We use a passage map, an obstacle map and a gradient map of obstacles to distinguish obstacles. A mid-level planner creates subgoals that help the robot efficiently cope with various obstacles using only a small set of locomotion primitives that are useful for stable navigation of the robot. We use a local obstacle map to find the subgoals along the global path. A low-level planner searches for an optimal sequence of locomotion primitives between subgoals by using fuzzy motion planning. We verify our approach on a virtual humanoid robot in a simulated environment. Simulation results show a reduction in planning time and the feasibility of the proposed method.

• 전자공학회논문지 IE
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• v.47 no.2
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• pp.21-26
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• 2010

This paper proposed an efficient algorithm to reduce the amount of calculation for Scalability Extension which takes a great deal of the operational time in H.264/AVC. This algorithm decides a search range according to the direction of predicted motion vector, and then performs an adaptive spiral search for the candidates with JM(Joint Model) FME(Fast Motion Estimation) which employs the rate-distortion optimization(RDO) method. Experimental results by applying the proposed method to various video sequences showed that the process time was decreased up to 80% comparing to the previous prediction methods. The degradation of video Quality was only from 0.05dB to 0.19dB and the compression ratio decreased as small as 0.58% in average. Therefore, we are sure that the proposed method is an efficient method for the fast inter prediction.

• Journal of the Korean Society for Precision Engineering
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• v.21 no.8
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• pp.164-170
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• 2004

The skin movement artifacts are referred to as the relative motion of skin with respect to the motion of underlying bones. This is of great importance in joint biomechanics or internal kinematics of human body. This paper describes a novel experiment that measures the skin movement of a hand based on MR(magnetic resonance) images in conjunction with surface modeling techniques. The proposed approach consists of 3 phases: (1) MR scanning of a hand with surface makers, (2) 3D reconstruction from the MR images, and (3) registration of the 3D models. The MR images of the hand are captured by 3 different postures. And the surface makers which are attached to the skin are employed to trace the skin motion. After reconstruction of 3D models from the scanned MR images, the global registration is applied to the 3D models based on the particular bone shape of different postures. The results of registration are then used to trace the skin movement by measuring the positions of the surface markers.

• Proceedings of the Korean Society of Broadcast Engineers Conference
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• 1998.06b
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• pp.147-153
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• 1998

This paper provides a method for video augmentation using image interpolation. In computer graphics or augmented reality, 3D information of a model object is necessary to generate 2D views of the model, which are then inserted into or overlayed on environmental views or real video frames. However, we do not require any three dimensional model but images of the model object at some locations to render views according to the motion of video camera which is calculated by an SFM algorithm using point matches under weak-perspective (scaled-orthographic) projection model. Thus, a linear view interpolation algorithm is applied rather than a 3D ray-tracing method to get a view of the model at different viewpoints from model views. In order to get novel views in a way that agrees with the camera motion the camera coordinate system is embedded into model coordinate system at initialization time on the basis of 3D information recovered from video images and model views, respectively. During the sequence, motion parameters from video frames are used to compute interpolation parameters, and rendered model views are overlayed on corresponding video frames. Experimental results for real video frames and model views are given. Finally, discussion on the limitations of the method and subjects for future research are provided.