• Journal of Broadcast Engineering
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• v.21 no.1
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• pp.43-50
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• 2016

In this paper, we present a distortion correction for wearable Augmented Reality (AR) on mobile phones. Head Mounted Display (HMD) using mobile phones, such as Samsung Gear VR or Google's cardboard, introduces lens distortion of the rendered image to user. Especially, in case of AR the distortion is more complicated due to the duplicated optical systems from mobile phone's camera and HMD's lens. Furthermore, such distortions generate mismatches of the visual cognition or perception of the user. In a natural way, we can assume that transparent wearable displays are the ultimate visual system which generates the least misperception. Therefore, the image from the mobile phone must be corrected to cancel this distortion to make transparent-like AR display with mobile phone based HMD. We developed a transparent-like display in the mobile wearable AR environment focusing on two issues: pincushion distortion and field-of view. We implemented our technique and evaluated their performance.

• Journal of the Korean Society of Surveying, Geodesy, Photogrammetry and Cartography
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• v.23 no.4
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• pp.401-408
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• 2005

Presently many constructions establish in underwater, but approaching to underwater constructions are difficult, for comparing with ground, underwater environment is different in media. Usually measurement methods for underwater constructions are using tapes, using depth gauges, using acoustic positioning systems. But, tapes are hard to measure the correct distance, for applying a right tension is not easy in underwater. Depth gauges have a weakness in settling, for it takes long time to do it. Acoustic positioning systems don't work well in confined spaces and cost a lot. Hence, the purpose of this study is, at first, to understand rays path in multimedia like water, glass and air. The second thing is to perform a camera calibration at the field to compare with the interior orientation parameter. And the third thing is to find out whether photogrammetry is applied for underwater object in using cube for accuracy examination. The last thing is to perform underwater photogrammetry about underwater object, which is pier model and riverbed. We came to the conclusion through this experiment that the applying underwater photogrammerty for underwater constructions and underwater ground is possible.

• Journal of Korea Multimedia Society
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• v.14 no.2
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• pp.171-181
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• 2011

A vision-based method for positioning and orienting of pallets is presented in this paper, which guides autonomous forklifts to engage pallets automatically. The method uses a single camera mounted on the fork carriage instead of two cameras for stereo vision that is conventionally used for positioning objects in 3D space. An image back-projection technique for determining the orient of a pallet without any fiducial marks is suggested in tins paper, which projects two feature lines on the front plane of the pallet backward onto a virtual plane that can be rotated around a given axis in 3D space. We show the fact that the rotation angle of the virtual plane on which the back-projected feature lines are parallel can be used to describe the orient of the pallet front plane. The position of the pallet is determined by using ratio of the distance between the back-projected feature lines and their real distance on the pallet front plane. Through a test on real pallet images, we found that the proposed method was applicable to real environment practically in real-time.

• Journal of the Korean Society of Visualization
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• v.5 no.1
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• pp.9-11
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• 2007

We introduce an in vivo imaging flow cytometer, which provides fluorescence images simultaneously with quantitative information on the cell population of interest in a live animal. As fluorescent cells pass through the slit of light focused across a blood vessel, the excited fluorescence is confocally detected. This cell signal triggers a strobe beam and a high sensitivity CCD camera that captures a snap-shot image of the cell as it moves down-stream from the slit. We demonstrate that the majority of signal peaks detected in the in vivo flow cytometer arise from individual cells. The instrument's capability to image circulating T cells and measure their speed in the blood vessel in real time in vivo is demonstrated. The cell signal irradiance variation, clustering percentage, and potential applications in biology and medicine are discussed.

• Transactions of the Korean Society of Mechanical Engineers B
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• v.34 no.11
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• pp.999-1004
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• 2010

Recently, many technologies have been developed in order to satisfy stringent emission regulations. However, in the case of diesel engines, the stringent emission regulations with respect to NOx and PM have not yet been satisfied. A dramatic reduction in the NOx and PM emissions could be achieved by using after-treatment systems such as lean NOx trap (LNT) and urea-SCR systems. However, the high temperature in the exhaust pipe affects the spray behavior of the secondary injector, which is used for supplying the Urea-SCR. Because of this high temperature, it is difficult to achieve uniform distribution of the reducing agent in the manifold. In this paper, the characteristics of a urea-SCR injector used for injecting in the exhaust pipe are presented. The purpose of this study was to investigate the spray characteristics of the injector, such as the spray angle, injection quantity, and SMD. In addition, laser diagnostics and high-speed-camera images were used to analyze the injector spray characteristics and to present a distribution of reduction in the transparent manifold.

• Journal of the Korean Society of Radiology
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• v.2 no.2
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• pp.23-30
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• 2008

X-ray microscopy with synchrotron radiation(SR) might be a useful tool for novel x-ray imaging in the clinical and laboratory settings. Microscopically, it enables us to observe detailed structure of animal organs samples with a great magnification power and an excellent resolution. The phase contrast mechanisms in image by X-ray are described. The phase-contrast X-ray imaging with SR from in-vivo and in-vitro mouse tail, rat nerve and rat lung were obtained with an 8 KeV monochromatic beam. The visual image was magnified using 10x microscope objective lens and captured using an digital CCD camera. The results showed more structural details and high resolution images with SR imaging system than conventional X-ray radiography system. The SR imaging system may have a potential for imaging in biological researches, material applications and clinical radiography.

• Journal of Biosystems Engineering
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• v.43 no.2
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• pp.103-109
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• 2018

Purpose: This study has been conducted to develop a potato yield monitoring system, consisting of a segmentation algorithm to detect potatoes scattered on a soil surface and a counting system to count the number of potatoes and convert the data from two-dimensional images to masses. Methods: First, a segmentation algorithm was developed using top-hat filtering and processing a series of images, and its performance was evaluated in a stationary condition. Second, a counting system was developed to count the number of potatoes in a moving condition and calculate the mass of each using a mass estimation equation, where the volume of a potato was obtained from its two-dimensional image, and the potato density and a correction factor were obtained experimentally. Experiments were conducted to segment potatoes on a soil surface for different potato sizes. The counting system was tested 10 times for 20 randomly selected potatoes in a simulated field condition. Furthermore, the estimated total mass of the potatoes was compared with their actual mass. Results: For a $640{\times}480$ image size, it took 0.04 s for the segmentation algorithm to process one frame. The root mean squared deviation (RMSD) and average percentage error for the measured mass of potatoes using this counting system were 12.65 g and 7.13%, respectively, when the camera was stationary. The system performance while moving was the best in L1 (0.313 m/s), where the RMSD and percentage error were 6.92 g and 7.79%, respectively. For 20 newly prepared potatoes and 10 replication measurements, the counting system exhibited a percentage error in the mass estimation ranging from 10.17-13.24%. Conclusions: At a travel speed of 0.313 m/s, the average percentage error and standard deviation of the mass measurement using the counting system were 12.03% and 1.04%, respectively.

• Journal of the Korean Society of Surveying, Geodesy, Photogrammetry and Cartography
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• v.17 no.1
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• pp.11-19
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• 1999

Lately, with the development of the fields of computer and photogrammetry, Digital Photogrammetric Systems are widely used for the generation of GIS basemap, the acquisition of topographic information and DEM, the formation of digital orthophoto, three-dimensional viewing and so on. According as the demand for the systems is rapidly increasing, we suggest keenly the necessity of domestic technical development, because all of these systems depend on foreign technology until now. In this study, by using digital photogrammetry method, with Visual C++ language, we have developed Digital Photogrammetric Systems for Windows which is able to get three-dimensional coordinates through interior orientation, exterior orientation, epipolar line, image matching from a pair of aerial photos taken with metric camera. This system consists of not only a module which can revise digital map that is being made at National Geographic Institute as a part of data construction project of National Geographic Information System, but also a module which can view three-dimensional image on the screen monitor by using anaglyph for three-dimensional analysis. The digital photogrammetry modules developed in this study are expected to be used as primary modules for the effective management of the urban as well as main modules in developing professional digital photogrammetric systems.

• The Journal of the Korea Contents Association
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• v.11 no.12
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• pp.629-638
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• 2011

Mobile game have an advantage of mobility, portability, and simple interface. These advantages are useful for gesture recognition based game which should not have much content quantity and complex interface. This paper suggests gesture recognition based mobile game content with user movement could be applied directly to the mobile game wherever recognition system is equipped. Gesture is recognized by obtaining user area in image from the depth image of TOF camera and going through SVM(Support Vectorn Machine) using EOH(Edge Of Histogram) features of user area. And we confirmed that gesture recognition can be utilized to user input of mobile game content. Proposed technique can be applied to a variety of content, but this paper shows a simple way of game contents which is consisted of moving and jumping newly.

• The Journal of Korea Robotics Society
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• v.4 no.1
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• pp.62-67
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• 2009

For diagnoses of digestive organs, capsule endoscopes are widely used and offer valuable information without patient's discomfort. A general capsule endoscope which consists of image sensing module, telemetry module and battery is able to move along gastro-intestinal tracts passively only through peristaltic waves. Thus, it is likely to have some limitations for doctor to acquire images from the desired organs and to diagnose them effectively. As solutions to these problems, a locomotive function of capsule endoscopes has being developed. We have proposed a capsule-type microrobot with synchronized multiple legs. However, the proposed capsular microrobot also has some limitations, such as low speed in advancement, inconvenience to controlling the microrobot, lack of an image module, and deficiency in a steering module. In this paper, we will describe the limitations of the locomotive microrobot and propose solutions to the drawbacks. The solutions are applied to the capsular microrobot and evaluated by in-vitro tests. Based on the experimental results, we conclude that the proposed solutions are effective and appropriate for the locomotive microrobot to explore inside intestinal tracts.