• Journal of Mechanical Science and Technology
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• v.15 no.12
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• pp.1775-1783
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• 2001

For two decades, there has been an active research to enhance the performances of Particle Image Velocimetry (PIV) systems. However, the resulting systems are somewhat very costly, cumbersome and delicate. In this paper, we address the design and some first experimental results of a PIV system belonging to the opposite paradigm. The Miniature PIV or MPIV system feature relatively modest performances, but is considerably smaller (out MPIV could hold in dia. 40 mm$\times$120 mm), cheaper (out MPIV total cost is less than $500) and easy to handle. Potential applications include industrial velocity sensors. The proposed MPIV system uses a one-chip-only CMOS camera with digital output. Only two other chips are needed, one for a buffer memory and one for an interfacing logic that controls the system. Images are transferred to a personal computer (PC or laptop) via its standard parallel port. No extra hardware is required (in particular, no frame grabber board is needed). In our first MPIV prototype presented in this paper, the strobe lighting is generated by a cheap 5 mW laser pointer diode. Experimental results are presented and discussed.

• Journal of IKEEE
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• v.24 no.2
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• pp.492-496
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• 2020

The visibility deteriorates in hazy weather and it is difficult to accurately recognize information captured by the camera. Research is being actively conducted to remove haze so that camera-based applications such as object localization/detection and lane recognition can operate normally even in hazy weather. In this paper, we propose a nonlinear model for depth map estimation through an extensive analysis that the difference between brightness and saturation in hazy image increases non-linearly with the depth of the image. The quantitative evaluation(MSE, SSIM, TMQI) shows that the proposed haze removal method based on the nonlinear model is superior to other state-of-the-art methods.

• Journal of the Korean Society of Visualization
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• v.6 no.2
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• pp.3-8
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• 2008

A new 3D-PTV algorithm(a Volume PTV) based upon a hybrid fitness function has been constructed. A coherency fitness function is introduced using the information of space and time to sort out the correct particle pairs between the two camera images. The measurement system consists of two-high-definition-cameras($1k{\times}1k$), a Nd-Yag laser and a host computer. The developed algorithm has been employed to investigate the flow features of the cylinder wake. The Reynolds numbers with the cylinder diameter(d=10 mm) are 360, 540, 720, 900, 1080 and 1260. Two-dimensional displacements of the particles of each camera's image and neighbouring constraints were introduced to reduce the calculation loads. More than 10,000 instantaneous 3D vectors have been obtained by the constructed algorithm. The constructed algorithm could recover more than $80{\sim}90%$ of the particle numbers in the image condition.

• Journal of Institute of Control, Robotics and Systems
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• v.19 no.6
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• pp.547-554
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• 2013

This paper proposes a novel formation algorithm of identical robots based on object tracking method using omni-directional images obtained through fisheye lenses which are mounted on the robots. Conventional formation methods of multi-robots often use stereo vision system or vision system with reflector instead of general purpose camera which has small angle of view to enlarge view angle of camera. In addition, to make up the lack of image information on the environment, robots share the information on their positions through communication. The proposed system estimates the region of robots using SURF in fisheye images that have $360^{\circ}$ of image information without merging images. The whole system controls formation of robots based on moving directions and velocities of robots which can be obtained by applying Lucas-Kanade Optical Flow Estimation for the estimated region of robots. We confirmed the reliability of the proposed formation control strategy for multi-robots through both simulation and experiment.

• Journal of Korea Multimedia Society
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• v.13 no.3
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• pp.400-409
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• 2010

This paper presents a position error recognition system when the wafer is mounted in cleaning equipment among the wafer manufacturing processes. The proposed system is to enhance the performance in cost and reliability by preventing the wafer cleaning system from damaging by alerting it when it is put in correct position. The key algorithms are the calibration method between image acquired from camera and physical wafer, a infrared lighting and the design of the filter, and the extraction of wafer boundary and the position error recognition resulting from generation of circle based on least square method. The system is to install in-line process using high reliable and high accurate position recognition. The experimental results show that the performance is good in detecting errors within tolerance.

• Proceedings of the Korean Institute of Navigation and Port Research Conference
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• 2002.11a
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• pp.121-126
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• 2002

This paper introduces a method that can get information for the movement of a spreader and skew in order to drive ALS(Automatic Landing System) in the crane used at the harbor. Some methods that use 3D laser scanner sensor or laser range finder to obtain the information in ALS are used presently. But these have some defects respectively in economical efficiency and performance. Therefore, to recover these defects, we propose a method acquiring the information for the movement of a spreader and skew using CCD camera for image processing and laser range finder

• Proceedings of the Korean Society of Broadcast Engineers Conference
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• 2009.01a
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• pp.601-605
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• 2009

We have proposed a measurement system for measuring a whole shape of an object easily. The proposed system consists of a camera and a cylinder whose inside is coated by a mirror layer. A target object is placed inside the cylinder and an image is captured by the camera from right above. The captured image includes sets of points that are observed from multiple viewpoints: one is observed directly, and others are observed via the mirror. Therefore, the whole shape of the object can be measured using stereo vision in a single shot. This paper shows that a prototype of the proposed system was implemented and an actual object was measured using the prototype. A method based on a pattern matching which uses a value of SSD (Sum of Squared Difference), and a method based on DP (Dynamic Programming) are employed to identify a set of corresponding points in warped captured images.

• Proceedings of the Korean Society of Broadcast Engineers Conference
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• 2009.01a
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• pp.760-763
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• 2009

"Watoji" is a Japanese traditional book binding technique. An aim of this research develops a support system which everyone can make Watoji easily by. This system uses a working situation by recognizing a position of a needle and annotating to a book directly by mixed reality technique. Additionally, a technique of recognizing a working situation at a book is sewn by a needle is proposed. The proposed system of recognizing a position of a needle is build, then we experiment recognizing of a needle from an image. Furthermore, setting up Watoji on the system, we experiment recognizing of a position of a needle. An experimental result shows recognizing a needle from an acquired image from a camera. Using this result, a working situation can be recognized. Then, suitable information to a working situation can be presented.

• Proceedings of the KSME Conference
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• 2000.04b
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• pp.673-679
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• 2000

LNG Carriers are currently known as sole commercial means of shipping natural gas on the sea. They are designed to proven dangerous explosion for shipping a lot of gas over long distance. In this study. In this study, a scaled model chamber was made to investigate ventilation characteristics of the hood room in LNG carrier. Experimental study was performed in model using visualization equipments with laser apparatus and image intensifier CCD camera gated by an AOM controller Twelve different kinds of measuring area were selected as experimental condition. Instant simultaneous velocity vectors at whole field were measured by using 2-D PIV system which software adopts two-frame grey-level cross correlation algorithm. To look into stagnation area of hood room for LNG carrier, a three-dimensional numerical simulation with standard ${\kappa}-{\varepsilon}$ model was carried out by using PHOENICS for three kinds of Reynolds number, $6.5{\times}10^3$, $9.7{\times}10^3\;and\;1.29{\times}10^4$, based on the cavity inlet velocity and cavity height. The flow pattern showed the large scale counter-clockwise forced-vortex rotated at center area, small eddies at each corner and stagnation area located at left-back upper side of model.

• Journal of Korea Society of Digital Industry and Information Management
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• v.8 no.2
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• pp.95-104
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• 2012

In this paper, an estimation of person height and 3D location of a moving person by using the pan/tilt-embedded stereo tracking system is suggested and implemented. In the proposed system, face coordinates of a target person is detected from the sequential input stereo image pairs by using the YCbCr color model and phase-type correlation methods and then, using this data as well as the geometric information of the stereo tracking system, distance to the target from the stereo camera and 3-dimensional location information of a target person are extracted. Basing on these extracted data the pan/tilt system embedded in the stereo camera is controlled to adaptively track a moving person and as a result, moving trajectory of a target person can be obtained. From some experiments using 780 frames of the sequential stereo image pairs, it is analyzed that standard deviation of the position displacement of the target in the horizontal and vertical directions after tracking is kept to be very low value of 1.5, 0.42 for 780 frames on average, and error ratio between the measured and computed 3D coordinate values of the target is also kept to be very low value of 0.5% on average. These good experimental results suggest a possibility of implementation of a new stereo target tracking system having a high degree of accuracy and a very fast response time with this proposed algorithm.