• 제목/요약/키워드: Dynamic Motion

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A Guideline for Motion-Image-Quality Improvement of LCD-TVs

  • Kurita, Taiichiro
    • 한국정보디스플레이학회:학술대회논문집
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    • 2009.10a
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    • pp.1164-1167
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    • 2009
  • Motion-image-quality of LCD-TVs is discussed by dynamic spatial frequency response. Smaller temporal aperture or higher frame rate can improve dynamic response, but an increase of motion velocity easily cancels the improvement. A guideline for deciding the desirable temporal aperture and frame rate of LCD-TVs is described, under the condition that camera and display have the same parameters. Two candidates of the desirable parameter sets will be (240 or 300 Hz, 50 to 100% aperture) and (120Hz, 25 to 50% aperture), from the viewpoint of "limit of acceptance" on motion-imagequality-deterioration for critical picture materials.

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The Application of Dynamic Acquisition with Motion Correction for Static Image (동적 영상 획득 방식을 이용한 정적 영상의 움직임 보정)

  • Yoon, Seok-Hwan;Seung, Jong-Min;Kim, Kye-Hwan;Kim, Jae-Il;Lee, Hyung-Jin;Kim, Jin-Eui;Kim, Hyun-Joo
    • The Korean Journal of Nuclear Medicine Technology
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    • v.14 no.1
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    • pp.46-53
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    • 2010
  • Purpose: The static image of nuclear medicine study should be acquired without a motion, however, it is difficult to acquire static image without movement for the serious patients, advanced aged patients. These movements cause decreases in reliability for quantitative and qualitative analysis, therefore re-examination was inevitable in the some cases. Consequently, in order to improve the problem of motion artifacts, the authors substituted the dynamic acquisition technique for the static acquisition, using motion correction. Materials and Methods: A capillary tube and IEC body phantom were used. First, the static image was acquired for 60 seconds while the dynamic images were acquired with a protocol, 2 sec/frame${\times}$30 frames, under the same parameter and the frames were summed up into one image afterwards. Also, minimal motion and excessive motion were applied during the another dynamic acquisition and the coordinate correction was applied towards X and Y axis on the frames where the motion artifact occurred. But the severe blurred images were deleted. Finally, the resolution and counts were compared between the static image and the summed dynamic images which before and after applying motion correction, and the signal of frequency was analysed after frequency spatial domain was transformed into 2D FFT. Supplementary examination, the blind test was performed by the nuclear medicine department staff. Results: First, the resolution in the static image and summed dynamic image without motion were 8.32 mm, 8.37 mm on X-axis and 8.30 mm, 8.42 mm on Y-axis, respectively. The counts were 484 kcounts, 485 kcounts each, so there was nearly no difference. Secondly, the resolution in the image with minimal motion applying motion correction was 8.66 mm on X-axis, 8.85 mm on Y-axis and had 469 kcounts while the image without motion correction was 21.81 mm, 24.02 mm and 469 kcounts in order. So, this shows the image with minimal motion applying motion correction has similar resolution with the static image. Lastly, the resolution in the images with excessive motion applying motion correction were 9.09 mm on X-axis, 8.83 mm on Y-axis and had 469 kcounts while the image without motion correction was 47.35 mm, 40.46 mm and 255 kcounts in order. Although there was difference in counts because of deletion of blurred frames, we could get similar resolution. And when the image was transformed into frequency, the high frequency was decreased by the movement. However, the frequency was improved again after motion correction. In the blind test, there was no difference between the image applying motion correction and the static image without motion. Conclusion: There was no significant difference between the static image and the summed dynamic image. This technique can be applied to patients who may have difficulty remaining still during the imaging process, so that the quality of image can be improved as well as the reliance for analysis of quantity. Moreover, the re-examination rate will be considerably decreased. However, there is a limit of motion correction, more time will be required to successfully image the patients applying motion correction. Also, the decrease of total counts due to deletion of the severe blurred images should be calculated and the proper number of frames should be acquired.

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Dynamic Analysis of a Slider in Near-field Optical Recording Disk Drive (근접장 광기록용 슬라이더의 동특성 분석)

  • 안채헌;임경화
    • Transactions of the Korean Society for Noise and Vibration Engineering
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    • v.13 no.3
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    • pp.164-171
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    • 2003
  • Dynamic analysis using impulse responses is formulated to estimate effect of slider rail shape on dynamic responses in near-field optical recording drive. Impulse responses are obtained on numerical nonlinear model including rigid motion of a slider and fluid motion of an air bearing under the slider. Dynamic characteristics of slider motion are evaluated by utilizing the decay ratio of impulse responses and modal frequencies from frequency response functions. The dynamic characteristics of the designed NFR slider are checked by comparing those of a HDD slider(Nutcracker). Also, sensitivities of slider Position conditions and rotation speed on the dynamic characteristics are investigated.

A Study on the Dynamic Load Model of Truss Bridge subjected to Moving Train Loads (열차하중을 받는 트러스교의 동적하중모형 연구)

  • 안주옥;박상준
    • Proceedings of the Computational Structural Engineering Institute Conference
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    • 1996.04a
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    • pp.111-118
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    • 1996
  • Dynamic load models which show the practical behavior of truss bridge subjected to moving train load are presented. Three basically approaches are available for evaluating structural response to dynamic effects : moving force, moving mass, and influence moving force and mass. Simple warren truss bridge model is selected in this research, and idealized lumped mass system, modelled as a planar structure. In the process of dynamic analysis, the uncoupled equation of motion is derived from simultaneous equation of the motion of truss bridge and moving train load. The solution of the uncoupled equations of motion is solved by Newmark-$\beta$ method. The results show that dynamic response of moving mass and static analysis considering the impact factor specified in the present railway bridge code was nearly the same. Generally, the dynamic response of moving force is somewhat greater than that of moving mass. The dynamic load models which are presented by this study are obtained relatively adequate load model when apply to a truss bridge.

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Dynamic Analysis of NFR Slider (NFR 슬라이더의 동특성 분석)

  • 안채헌;임경화
    • Proceedings of the Korean Society for Noise and Vibration Engineering Conference
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    • 2001.11b
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    • pp.586-591
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    • 2001
  • Dynamic analysis using impulse responses is formulated to estimate effect of slider rail shape on dynamic responses. Impulse responses are obtained on numerical nonlinear model including rigid motion of slider and fluid motion of air bearing under the slider. Dynamic characteristics of slider motion are evaluated by utilizing the decay ratio of impulse responses and modal frequencies from frequency response functions. The dynamic characteristics of the developed NFR(Near Field Recording) slider are checked by comparing those of HDD sider(Nutcracker). Also, sensitivities of slider position conditions and rotation speed on the dynamic characteristics are investigated. The researches show that the utilized method is a good indicator of designing the better slider.

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Appropriate Input Earthquake Motion for the Verification of Seismic Response Analysis by Geotechnical Dynamic Centrifuge Test (동적원심모형 시험을 이용한 부지응답해석 검증시 입력 지진의 결정)

  • Lee, Jin-Sun
    • Journal of the Earthquake Engineering Society of Korea
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    • v.17 no.5
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    • pp.209-217
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    • 2013
  • In order to verify the reliability of numerical site response analysis program, both soil free-field and base rock input motions should be provided. Beside the field earthquake motion records, the most effective testing method for obtaining the above motions is the dynamic geotechnical centrifuge test. However, need is to verify if the motion recorded at the base of the soil model container in the centrifuge facility is the true base rock input motion or not. In this paper, the appropriate input motion measurement method for the verification of seismic response analysis is examined by dynamic geotechnical centrifuge test and using three-dimensional finite difference analysis results. From the results, it appears that the ESB (equivalent shear beam) model container distorts downward the propagating wave with larger magnitude of centrifugal acceleration and base rock input motion. Thus, the distortion makes the measurement of the base rock outcrop motion difficult which is essential for extracting the base rock incident motion. However, the base rock outcrop motion generated by using deconvolution method is free from the distortion effect of centrifugal acceleration.

Development of a Real-time Vehicle Driving Simulator

  • Kim, Hyun-Ju;Park, Min-Kyu;Lee, Min-Cheoul;You, Wan-Suk
    • 제어로봇시스템학회:학술대회논문집
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    • 2001.10a
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    • pp.51.2-51
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    • 2001
  • A vehicle driving simulator is a virtual reality device which makes a human being feel as if the one drives a vehicle actually. The driving simulator is effectively used for studying interaction of a driver-vehicle and developing the vehicle system of new concepts. The driving simulator consists of a motion platform, a motion controller, a visual and audio system, a vehicle dynamic analysis system, a vehicle operation system and etc. The vehicle dynamic analysis system supervises overall operation of the simulator and also simulates dynamic motion of a multi-body vehicle model in real-time. In this paper, the main procedures to develop the driving simulator are classified by 4 parts. First, a vehicle motion platform and a motion controller, which generates realistic motion using a six degree of freedom Stewart platform driven hydraulically. Secondly, a visual system generates high fidelity visual scenes which are displayed on a screen ...

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Modeling and Motion Control of Piezoelectric Actuator for the Inchworm : Part 2. Motion Control of Inchworm Using Sliding Mode Method (이송자벌레를 위한 압전소자의 모델링 및 운동제어 : 2. 슬라이딩 모드법에 의한 이송자벌레의 운동제어)

  • Kim, Young-Shik;Park, Euncheol;Kim, In-Soo
    • Transactions of the Korean Society for Noise and Vibration Engineering
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    • v.15 no.7 s.100
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    • pp.878-884
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    • 2005
  • This paper presents an algorithm for the precision motion control based on the dynamic characteristics of piezoelectric actuators in the inchworm. The dynamic characteristics are identified by the frequency domain modeling technique using the experimental data. For the motion control, the hysteresis behavior is compensated by the inverse hysteresis model. The dynamic stiffness of an inchworm is generally low compared to its driving condition, so mechanical vibration may degenerate the motion accuracy of the inchworm. The Sliding mode controller and the Kalman filter are designed for motion control of the inch-worm.

Parallel-Jaw Grasp Planning of Polygonal Parts in Uncertain Dynamic Environments (불확실 동적 환경에서 다각형 부품의 평행-턱 파지 계획)

  • Han, Inhwan;Cho, Jeongho
    • Journal of the Korean Society for Precision Engineering
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    • v.14 no.4
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    • pp.126-135
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    • 1997
  • A sensorless motion planner which succeeds in grasping a polygonal part firmly into a desired orientation has been developed through the dynamic analysis. The analytical results on the impact process with friction are used for modeling the contact motionduring the parallel-jaw grasp operation, which is com- posed of the pushing and the squeezing process. The developed planner succeeds in grasping a part into a specified orientation in the face of uncertainties of initial position and orientation of the part, motion direction of the finger, and the physical parameters such as the coefficients of friction and restitution. The motion planner has been fully implemented into a viable package on the computer system, and verified experimentally. The motion of parts is recorded using a high-speed video camera, and then compared to the results of the planner and the graphic simulation results that illustrate the simulated motion of the grasp operation.

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The Prediction of the Dynamic Transmission Error for the Helical Gear System (헬리컬 기어계의 동적 전달오차의 예측)

  • Park, Chan-Il;Cho, Do-Hyun
    • Transactions of the Korean Society of Mechanical Engineers A
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    • v.28 no.9
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    • pp.1359-1367
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    • 2004
  • The purpose of this study is to predict the dynamic transmission error of the helical gear system. To do so, the equations of motion in the helical gear system which consists of motor, coupling, gear, torque sensor, and brake are derived. As the input parameters, the mass moment of inertia by a 3D CAD software and the equivalent stiffness of the bearings and shaft are calculated and the coupling stiffness is measured. The static transmission error as an excitation is calculated by in-house program. Dynamic transmission error is predicted by solving the equations of motion. Mode shape, the dynamic mesh force and the bearing force are also calculated. In this analysis, the relationship between the dynamic mesh force and the bearing force and mode shape behavior in gear mesh are checked. As a result, the magnitude of mesh force is highly related with the gear mesh behavior in mode shape. The finite element analysis is conducted to find out the natural frequency of gear system. The natural frequencies by finite element analysis have a good agreement with the results by equation of motion. Finally, dynamic transmission error is measured by the specially designed experiment and the results by equation of motion are validated.