• Journal of the Korean Society of Marine Environment & Safety
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• v.21 no.5
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• pp.531-537
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• 2015

In order to maximize power output from the solar panels, one needs to keep the panels aligned with the sun. So solar tracker having high reliability must be designed. This paper cares about the design and evaluation of a two-axis solar tracker system based on fuzzy logic control with LabVIEW. The research focus on planning mechanical parts, making an intelligent controller which controls and monitors all parameters via user interface implemented of a fuzzy decision support system for control of photovoltaic panel movement. We also develop a real solar tracker system and analyze the influence indexes such as environment, weather, season, and light condition. The solar tracker is tested in real condition and all parameters related to the system operation are recorded and analyzed. The developed solar tracking system got a much higher efficiency about 38 % compare to fixed solar panel although the weather condition is affected a lot to the solar panel. So we confirmed the our auto tracking system is more effective and can allow more energy to be produced.

• The Journal of the Society of Korean Medicine Diagnostics
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• v.16 no.3
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• pp.41-48
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• 2012

Objectives: The aims of this study are to design a optimized mechanical structure of digital tongue imaging system (DTIS) equipped with LEDs in aspects of object distance and camera angle of coverage. Methods and Results: We tried to find optimized object distance while recording a rectangular object of common tongue size. In case object distance is 22 cm or less, edge of the rectangle was not taken beyond the shooting range. In contrast, if object distance is 40 cm or more, the rectangle image was too small. Therefore when considering the variation of subjects, we selected distance of 35-40 cm as appropriate object distance for the DTIS. We also tried to find optimized angle between camera view axis and horizontal line. We photographed from the side of the face of 7 adults with exposed tongue. We drew an exposed tongue lines to connect the tongue tip points and the tongue root points by using the photos acquired from the side faces. And then we calculated the tongue exposure angles between the vertical line and the exposed tongue lines. Mean tongue exposure angle was $28.3^{\circ}$ when tongue was lightly exposed and $13.3^{\circ}$ when maximally. So we determined $73^{\circ}$ as appropriate slope angle of part in contact with face of the DTIS and by considering that the standard variation was great, we designed control gears to adjust the slope of the camera view axis and to regulate the object distance. Conclusions: We designed a optimized mechanical structure in object distance and slope angle of part in contact with face of the DTIS.

• Journal of the Optical Society of Korea
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• v.17 no.4
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• pp.336-343
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• 2013

Recently various types of driver assistance systems have been used for automobiles. In 2008, the U.S Congress passed a law which required that most cars be equipped with devices to warn objects behind the vehicle. Because of that, market of rear view cameras is expected to rise dramatically. Therefore many suppliers try to provide a wide angle camera for car makers. But a high distortion is caused by the wide angle might result in lower image quality. In order to improve the image quality, normally we use an algorithm to correct a distortion. Though we can improve the distorted image by correction algorithm, we must pay more cost to use it. In this paper, we propose a new optical system reducing a distortion in contrast to a conventional lens without cost. In other words, we can see only an area of interest. That is similar to reducing a field of view. Using a new optical system, we can get a less distorted image. In order to view an area of interest, we introduce an off axis optical system having refractive surfaces and reflective surfaces. In this paper, we describe the results of design and, evaluation of an off axis wide angle compact imaging system. In comparison to conventional wide angle lens, we can get the improvement of MTF, distortion, and lateral color aberrations. And we also can reduce a total cost because we don't need the outer apparatus or bracket to mount on the car.

• Journal of the korean academy of Pediatric Dentistry
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• v.36 no.3
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• pp.325-336
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• 2009

The purpose of this study was to investigate the eruption pattern of the mandibular first molar in sagittal, frontal and horizontal views using the cone beam CT scanning. CT images were obtained from healthy 83 children (42 boys, 41 girls) between 3 to 10 years of age with a normal dentition according to Nolla stage. 1. In the frontal and horizontal view, the intermolar width decreased continuously with stage and slightly increased at the last stage. 2. In the sagittal and frontal view, eruption distances from occlusal plane were observed the largest change between stage 5 and 7. 3. In the horizontal and sagittal view, mandibular first molar from distal surface of primary second molar moved distally between stage 4 and 6. 4. In the sagittal view, angle from occlusal plane to mesio-distal axis increased between stage 4 and 8. 5. In the frontal view, angle from occlusal plane to bucco-lingual axis increased continuously during all stage. 6. In the horizontal view, angle from midsagittal plane to long axis increased between stage 5 and 8.

• Journal of Korean Ophthalmic Optics Society
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• v.11 no.1
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• pp.63-69
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• 2006

Clinical evaluation by Astigmatic Components of autorefractors was performed to examine validity and accuracy compared with subjective refraction. The mean cylindrical powers of Astigmatic Components of Subjective Refraction, Closed-view and Open-view were found to be $-0.689{\pm}0.516D$, $-0.691{\pm}0.530D$, $-0.470{\pm}0.507D$, respectively. The Difference of cylindrical Components between Subjective Refraction and Closed, Open-view were found to be $0.002{\pm}0.191D$, $0.015{\pm}0.137D$, respectively. Approximately 85% of Closed-view and Open-view autorefractor measurements were within ${\pm}20^{\circ}$ range of the difference of cylindrical axis with subjective refraction. The mean $J_0$ Components of Astigmatic Components of subjective refraction, Closed-view and Open-view were found to be $-0.155{\pm}0.332D$, $-0.004{\pm}0.178D$, $-0.001{\pm}0.156D$, respectively. The mean $J_{45}$ Components of Astigmatic Components, Closed-view and Open-view were found to be $-0.023{\pm}0.227D$, $-0.026{\pm}0.172D$, $-0.014{\pm}0.182D$, respectively. Both of the Closed-view and Open-view refractor showed available accuracy in measuring astigmatic components.

• Korean Journal of Optics and Photonics
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• v.9 no.2
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• pp.59-62
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• 1998

One dimensional inhomogeneous aperture modulation effects on the MTF of optical system was investigated. The lens undertest was a doublet made in Korea. It was 10 mm effective diameter, 87.8 mm effective focal length. The ray-fans and spot diagrams were caluculated and presented on the picture for on-axis and off-axis (field of view, 1$^{\circ}$ and 2$^{\circ}$). Aperture modulation was carried out by positioning a aperture modulator close contacted with the lens undertest. We bought two modulators from Edmud Company in U.S.A. One was linear type and the other was stepped type. The MTFs were measured on the best of focus for unmodulated apertue where the MTF has the largest value for 60 c/mm and were compared with one another. The MTFs of modulated apertures had a little lower values than the MTF of unmodulated aperture for on-axis but in the case off-axis, the values are highly improved as much as the wider field of view by modulating on the aperture.

• Proceedings of the Korean Environmental Sciences Society Conference
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• 2003.11a
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• pp.185-191
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• 2003

Walled town was located on the axis connecting symbolic places, which was a feng-shui lucky place of a mountain sits to the rear and a body of water sits to the front. It represents environmental development of cultural space by blend of folk belief, religion, social system, administration facilities and living culture buildings. Therefore it is sustainable cultural view connected of formed or formless religious view and artificial view(wall, government buildings, living houses, and cultivated land so on) in a nature landscape. Environmental design technique, enlarging its meaning and value of living to mental level was founded from space composition and settlement, which was constructed organized space of government and residence area of walled town within the wall for looking for lucky place(from best, better, and good places) in order to construct ecological network (天+地+人, 山＋水＋方位＋人, 地理＋生利＋山水＋人心) by outlook of space and settlement.

• Proceedings of the KIEE Conference
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• 2007.04a
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• pp.322-324
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• 2007

In this paper, an eye-in-hand visual servoing strategy for keeping feature points within the FOV(field-of-view) is proposed. We first specify the FOV constraint which must be satisfied to keep the feature points within the FOV. It is expressed as the inequality relationship between (i) the LOS(jine-of-sight) angles of the center of the feature points from the optical axis of the camera and (ii) the distance between the object and the camera. We then design a nonlinear feedback controller which decouples linearly the translational and rotational control loops. Finally, we show that appropriate choice of the controller gains assures to satisfy the FOV constraint. The main advantage of our approach over the previous ones is that the trajectory of the camera is smooth and circular-like. Furthermore, ours can be applied to the large camera displacement problem.

• Journal of the Korean Society of Manufacturing Technology Engineers
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• v.6 no.2
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• pp.10-18
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• 1997

This paper presents the development of real-time estimation and control details for a computer vision-based robot control method. This is accomplished using a sequential estimation scheme that permits placement of these points in each of the two-dimensional image planes of monitoring cameras. Estimation model is developed based on a model that generalizes know 4-axis Scorbot manipulator kinematics to accommodate unknown relative camera position and orientation, etc. This model uses six uncertainty-of-view parameters estimated by the iteration method. The method is tested experimentally in two ways : First the validity of estimation model is tested by using the self-built test model. Second, the practicality of the presented control method is verified in performing 4-axis manipulator's assembly task. These results show that control scheme used is precise and robust. This feature can open the door to a range of application of multi-axis robot such as deburring and welding.

• Transactions of Materials Processing
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• v.13 no.3
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• pp.273-278
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• 2004

This paper subscribes the measurement system that can position the target to measure by moving 2-axis stage, which is controlled by the data from image processing technique. The high resolution camera and lens are used in measurement of micro mechanical part, but the region of measurement is very small. It is necessary the re-positioning to measure several regions in one part. The system described in this paper has the accuracy with about $0.9\mu\textrm{m}$ resolution per one pixel and can be applied to measure micro mechanical part.