• 한국정보디스플레이학회:학술대회논문집
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• 2007.08b
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• pp.1135-1138
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• 2007

This paper presents motion picture artifacts measured with a high-speed camera. Measurement results of the high-speed camera on moving targets will be evaluated and compared with motion blur data derived from step responses measured on stationary test patterns with a spot-photodetector.

• Current Industrial and Technological Trends in Aerospace
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• v.6 no.2
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• pp.125-132
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• 2008

High speed camera is very important and essential device to analyze the motion of fast moving object in detail. This paper describes the basic concepts of the high speed film camera and high speed digital camera and the history and future technical trends in high speed camera industry. In addition, application field of high speed camera in Korea as well as other countries and future plan to use high speed camera in Naro Space Center has been descried.

• KSTLE International Journal
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• v.8 no.1
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• pp.16-20
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• 2007

This study introduces a new approach to a falling ball viscometer by using a high speed motion camera to measure the viscosity of both Newtonian and non-Newtonian fluids from the velocity-time data. This method involves capturing continuous photographs of the entire falling motion of the ball as the ball accelerates from the rest to the terminal velocity state. The velocity of a falling ball was determined from the distance traversed by the ball by examining video tape frame by frame using the marked graduations on the surface of the cylinder. Each frame was pre-set at 0.01. Glycerin 74% was used for Newtonian solution, while aqueous solutions of Polyacrylamide and Carboxymethyl Cellulose were for non-Newtonian solutions. The experimental viscosity data were in good agreements with the results obtained from a rotating Brookfield viscometer.

• Journal of the Korean Society for Precision Engineering
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• v.19 no.10
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• pp.163-170
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• 2002

The dynamic model of a high-speed vacuum circuit breaker mechanism with spring-actuated cam and linkage is derived to simulate the high-speed closing and opening operations. Its validation for an analysis of high-speed motion behavior is checked through experiments. The characteristics of the friction on the camshaft are investigated using the nonlinear pendulum experiment. The parameters of the friction model are estimated using the optimization technique. The analysis exhibits that the friction of the pendulum depends on stick-slip, Stribeck effect and viscous damping. Comparing simulation results with actual responses using a high-speed camera, the appropriateness of derived dynamic models for the rapid closing and opening operations is shown. The spring motion, which has much influence on the closing responses, is observed.

• Proceedings of the KSME Conference
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• 2007.05b
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• pp.3015-3020
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• 2007

An experimental study of the dynamic characteristics of the free rising oblate spherical bubble is investigated. As noted by Saffman, the characteristics of the spiral motion are defined with parameters of the spiral frequency, spiral radius, and rising velocity. High speed camera recorded every detail information of free rising bubble. The spiral number, the bubble rise velocity, and the angular velocities were measured for the bubble size between 1.0mm to 20.0mm in diameter. In order to make clear trajectory, we employed the Fast Fourier Transformation for the normal digital camera data to synchronize with the high speed camera data. It was found that the spiral number suggested here was monotonically decreased as the bubble size increases. The present observation, however tells us that previous Saffman's formulation shows a good agreement with the trend, but over estimated spiral number. Therefore, it is recommended that Saffman's theoretical study is needed to be improved.

• Proceedings of the Korean Institute of Information and Commucation Sciences Conference
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• 2017.10a
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• pp.536-538
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• 2017

UHD high speed digital camera system will be installed around launch pad and launch complex tower to acquire high speed image for motion analysis of integral parts of launch vehicle during the lift-off of KSLV-II in the Naro space center. In this paper, We compared configuration of high speed digital camera system operating in the Naro space center with UHD high speed digital camera system for mission of KSLV-II.

• Physical Therapy Korea
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• v.29 no.4
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• pp.262-268
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• 2022

Background: Virtual reality (VR) programs based on motion capture camera are the most convenient and cost-effective approaches for remote rehabilitation. Assessment of physical function is critical for providing optimal VR rehabilitation training; however, direct muscle strength measurement using camera-based kinematic data is impracticable. Therefore, it is necessary to develop a method to indirectly estimate the muscle strength of users from the value obtained using a motion capture camera. Objects: The purpose of this study was to determine whether the pedaling speed converted using the VR engine from the captured foot position data in the VR environment can be used as an indirect way to evaluate knee muscle strength, and to investigate the validity and reliability of a camera-based VR program. Methods: Thirty healthy adults were included in this study. Each subject performed a 15-second maximum pedaling test in the VR and built-in speedometer modes. In the VR speedometer mode, a motion capture camera was used to detect the position of the ankle joints and automatically calculate the pedaling speed. An isokinetic dynamometer was used to assess the isometric and isokinetic peak torques of knee flexion and extension. Results: The pedaling speeds in VR and built-in speedometer modes revealed a significantly high positive correlation (r = 0.922). In addition, the intra-rater reliability of the pedaling speed in the VR speedometer mode was good (ICC [intraclass correlation coefficient] = 0.685). The results of the Pearson correlation analysis revealed a significant moderate positive correlation between the pedaling speed of the VR speedometer and the peak torque of knee isokinetic flexion (r = 0.639) and extension (r = 0.598). Conclusion: This study suggests the potential benefits of measuring the maximum pedaling speed using 3D depth camera in a VR environment as an indirect assessment of muscle strength. However, technological improvements must be followed to obtain more accurate estimation of muscle strength from the VR cycling test.

• Journal of the Korean Society for Precision Engineering
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• v.27 no.9
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• pp.43-51
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• 2010

Speed, accuracy and smoothness are the important properties of pan-tilt camera. In the case of a high ratio zoom lens system, low vibration characteristic is a crucial point in driving pan-tilt mechanism. In this paper, a novel micro-stepping controller with a function of reducing vibration was designed using field programmable gate arrays (FPGA) technology for high zoom ratio pan-tilt camera. The proposed variable reference current (VRC) control scheme reduces vibration decently and optimizing coil current in order to prevent the step motor from occurring missing steps. By employing VRC control scheme, the vibration in low speed could be significantly minimized. The proposed controller can also make very high speed of 378kpps micro-step driving, and increase maximum acceleration in motion profiles.

• Journal of Digital Contents Society
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• v.15 no.3
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• pp.425-432
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• 2014

4K high speed camera shooting enables shooting of fast subjects in Full HD 4 times resolution without motion blur due to increase in resolution and shutter speed. However, this shooting incurs several limitations including focus, intensity of radiation and increase in data quantity. As lack of intensity of radiation may occur due to increased shutter speed, it is shoot by opening aperture and limitation in focusing follows. In addition, there is limitation in shooting records since it has restriction in storage due to increased resolution and frame rate. In this regard, this study aims to analyze the limitations shown above through production case of 4K high speed camera (Phantom Flex 4K) and to design effective workflow to overcome this.

• Proceedings of the Korean Society for Noise and Vibration Engineering Conference
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• 2008.11a
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• pp.61-68
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• 2008

A set of modal parameters of a stay-cable have been extracted from a moving picture captured by a digital camera supported by shaking hands. It is hard to identify the center of targets attached on the cable surface from the blurred cable motion image, because of the high speed motion of cable, low sampling frequency of camera, and the shaking effect of camera. This study proposes a multi-template matching algorithm to resolve such difficulties. In addition, a sensitivity-based system identification algorithm is introduced to extract the natural frequencies and damping ratios from the ambient cable vibration data. Three sets of vibration tests are conducted to examine the validity of the proposed algorithms. The results show that the proposed technique is pretty feasible for extracting modal parameters from the severely shaking motion pictures.