• The Journal of Korean Institute of Information Technology
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• v.17 no.1
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• pp.149-156
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• 2019

Mixed reality technology (MR) has become one of the fourth industrial revolution element technologies. MR technology has been widely applied not only as a digital contents industry but also in the fields of architecture, tourism, medical field, and education. In this paper, we propose a collaborative service platform for architectural applications that inter-operate with heterogeneous devices such as MR device, PC and mobile, and develop prototype system and verify it. As a result, the 3D model using the skp extension, which is mainly used in architecture design office, was created by using developed prototype system and generate the MR contents for the hololens, which is the MR device, and the conversion time and normal operation were confirmed.

• 한국신재생에너지학회:학술대회논문집
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• 2010.06a
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• pp.81-81
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• 2010

유리기판위에 큰 결정입자를 갖는 실리콘 (폴리 실리콘) 박막을 제조하는 것은 가격저가화 및 대면적화 측면 같은 산업화의 높은 잠재성을 가지고 있기 때문에 그동안 많은 관심을 가지고 연구되어 오고 있다. 다양한 방법을 이용하여 다결정 실리콘 박막을 만들기 위해 노력해 오고 있으며, 태양전지에 응용하기 위하여 연속적이면서 10um이상의 큰 입자를 갖는 다결정 실리콘 씨앗층이 필요하며, 고속증착을 위해서는 (100)의 결정성장방향 등 다양한 조건이 제시될 수 있다. 다결정 실리콘 흡수층의 품질은 고품질의 다결정 실리콘 씨앗층에서 얻어질 수 있다. 이러한 다결정 실리콘의 에피막 성장을 위해서는 유리기판의 연화점이 저압 화학기상증착법 및 아크 플라즈마 등과 같은 고온기반의 공정 적용의 어려움이 있기 때문에 제약 사항으로 항상 문제가 제기되고 있다. 이러한 관점에서 볼때 유리기판위에 에피막을 성장시키는 방법으로 많지 않은 방법들이 사용될 수 있는데 전자 공명 화학기상증착법(ECR-CVD), 이온빔 증착법(IBAD), 레이저 결정화법(LC) 및 펄스 자석 스퍼터링법 등이 에피 실리콘 성장을 위해 제안되는 대표적인 방법으로 볼 수 있다. 이중에서 효율적인 관점에서 볼때 IBAD는 산업화측면에서 좀더 많은 이점을 가지고 있으나, 박막을 형성하는 과정에서 큰 에너지 및 이온크기의 빔 사이즈 등으로 인한 표면으로의 damages가 일어날 수 있어 쉽지 않는 방법이 될 수 있다. 여기에서는 이러한 damage를 획기적으로 줄이면서 저온에서 결정화 시킬 수 있는 cold annealing법을 소개하고자 한다. 이온빔에 비해서 전자빔의 에너지와 크기는 그리드 형태의 렌즈를 통해 전체면적에 조사하는 것을 쉽게 제어할 수 있으며 이러한 전자빔의 생성은 금속 필라멘트의 열전자가 아닌 Ar플라즈마에서 전자의 분리를 통해 발생된다. 유리기판위에 흡수층 제조연구를 위해 DC 및 RF 스퍼터링법을 이용한 비정질실리콘의 박막에 대하여 두께별에 따른 밴드갭, 캐리어농도 등의 변화에 대하여 조사한다. 최적의 조건에서 비정질 실리콘을 2um이하로 증착을 한 후, 전자빔 조사를 위해 1.4~3.2keV의 다양한 에너지세기 및 조사시간을 변수로 하여 실험진행을 한 후 단면의 이미지 및 결정화 정도에 대한 관찰을 위해 SEM과 TEM을 이용하고, 라만, XRD를 이용하여 결정화 정도를 조사한다. 또한 Hall효과 측정시스템을 이용하여 캐리어농도, 이동도 등을 각 변수별로 전기적 특성변화에 대하여 분석한다. 또한, 태양전지용 흡수층으로 응용을 위하여 dark전도도 및 photo전도도를 측정하여 광감도에 대한 결과가 포함된다.

• Journal of the Institute of Electronics Engineers of Korea SP
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• v.47 no.4
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• pp.90-96
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• 2010

The focusing system is an important factor to determine the imaging quality of a digital imaging system. The focusing system consist of measuring the focusing index with high frequency energy of an image and controlling the movement of the focusing lens based on the computed focusing index. The computation of the focusing index is a key aspect in implementing the focusing system and the noise of the image cause the error in the sharpness evaluation of the image. To reduce this error, the noise under the low illumination condition is considered. A noise insensitive focusing index using adaptive weights is proposed in this paper. This measure determines the sharpness of an image using the spatially adaptive weights based on the local statistics of the image and noise. Experimental results under the condition without and with the noise verify the performance of the proposed method.

• Journal of the Institute of Electronics Engineers of Korea SD
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• v.39 no.3
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• pp.34-40
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• 2002

In this paper, a new encryption method for a binary image using Phase modulation and Fourier transform is proposed. For decryption we use the characteristics of square law detector. In encryption process, a key image is obtained by phase modulation of 256 level random pattern and its Fourier transformation, and input image is encrypted by Fourier transforming the multiplication of the phase modulated random pattern and phase modulated input image. The encrypted image and key image have only phase information, so they can not be copied or counterfeited and the original image can not be decrypted without the key image. To reconstruct the original image, each phase mask of the key image and the encrypted image must be placed on each path of the Mach-Zehnder interferometry with Fourier transform lens and the output image is obtained in the form of intensity in the CCD(Charge Coupled Device) camera. The real-time decryption is possible in the proposed system by use of a LCD as a phase modulator and a CCD camera as an intensity detector. The proposed method shows a good performance in the computer simulation and optical experiment as an encryption scheme.

• Journal of the Institute of Electronics Engineers of Korea SP
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• v.48 no.6
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• pp.27-34
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• 2011

In this paper, we propose an active 3D shape acquisition method based on photometric stereo using camera and flash on a smartphone. Two smartphones are used as the master and slave, in which the slave projects illumination from different locations while the master captures the images and processes photometric stereo algorithm to reconstruct 3D shape. In order to reduce the error, the smartphone's camera is calibrated to overcome the effect of the lens distortion and nonlinear camera sensor response. We apply 5-point algorithm to estimate the pose between smartphone cameras and then estimate lighting direction vector to run the photometric stereo algorithm. Experimental result shows that the proposed system enables us to use smartphone as a 3D camera with low cost and high quality.

• The Journal of the Korea institute of electronic communication sciences
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• v.8 no.12
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• pp.1923-1932
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• 2013

In order to solve the problem of severely distorted images from a wide-angle camera, we propose a calibration method which corrects a radial distortion in wide-angle images by estimation and validation of camera model. First, we estimate a camera model consisting of intrinsic and extrinsic parameters from calibration patterns, where intrinsic parameters are the focal length, the principal point and so on, and extrinsic parameters are the relative position and orientation of calibration pattern from a camera. Next we validate the estimated camera model by re-extracting corner points by inversing the model to images. Finally we correct the distortion of the image using the validated camera model. We confirm that the proposed method can correct the distortion more than 80% by the calibration experiments using the lattice shaped pattern images captured from a general web camera and a wide-angle camera.

• Applied Microscopy
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• v.33 no.3
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• pp.187-193
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• 2003

When electron microscope images and selected area diffraction patterns of crystalline materials are being compared, it is important to know for the rotation of the diffraction pattern with respect to the image caused by the magnetic lens in the Electron Microscope. A well-known method to determine this rotation is to use a test crystal of $MoO_3$. But this method of determination of the rotation angle contains an uncertainty of $180^{\circ}$. Thus one has to devise another way to eliminate this uncertainty. In this paper we present a new and simple method of determining this rotation without any complexity. The method involves a process of obtaining LACBED patterns of crystalline materials. For the J2010 electron microscope, the rotation is determined to be $180^{\circ}$ and this angle remains unchanged for changing of the magnification and the camera length.

• The Journal of Korea Institute of Information, Electronics, and Communication Technology
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• v.4 no.1
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• pp.23-31
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• 2011

In this paper, the intelligent smart monitor system is implemented for the next generation vehicle. to mitigate the numerous effects of distractions within the vehicle, it is vital to put critical information where the driver can use it without affection focus on the road ahead. Audible alarms are useful supplements when used in conjunction with visual displays. But driving is an overwhelmingly visual task. To optimize a vehicle's active safety systems, more than just audible alarms are necessary. The driver needs a visual interface that focuses his or her attention on the road ahead. The most commonly viewed information in a vehicle is from the instrument cluster, where speed, tachometer, fuel, engine temperature, fuel gauge, turn indicators and warning lights provide the driver with an array of fundamental information. TFT LCD, LCD Back light led, plane mirror, lens and controllers parts were designed to intelligent integrated smart monitor system. Finally, in this paper, we analyze intelligent integrated smart monitor system for driver safety vehicles.

• Journal of the Korean Institute of Electrical and Electronic Material Engineers
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• v.27 no.5
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• pp.307-311
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• 2014

Because of a waveguiding effect and total internal reflection caused by a difference in refractive indices, only 20% of generated light is emitted to the air and the rest is trapped or absorbed in the device. An improvement of outcoupled efficiency of organic light-emitting diodes was studied using a microlens array. Mold of microlens array was fabricated by using photo-lithography with the AZ9260 photoresist, and the microlens array was formed onto the glass substrate using the UV curing agent named ZPU13-440. Device structure consists of microlens/glass/ITO/TPD/$Alq_3$/LiF/Al. It was found that there is an improvement of external quantum efficiency by about 20% at the same current density for the device with the microlens array compared to that of the reference one. Simulated outcoupled efficiency shows the improvement by about 20% for the device with the microlens array compared to that of the reference one. These results are consistent with the experimental ones.

• Journal of the Institute of Electronics Engineers of Korea SC
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• v.43 no.1 s.307
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• pp.1-6
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• 2006

The noncontact optical sensor using the hologram laser and automatic power controller is developed to measure a thickness of transparent objects and achieve excellent performance. Due to the contact between the tip of the sensor and the surface of objects, the tip is abraded. In addition the casting glass under high temperature results in extending the size of sensor body. The accuracy of the sensor is degraded due to these reasons. In this paper, to overcome these problems, we proposed a low cost non-contact optical sensor that is composed of a hologram laser unit used for optical pickup of CD player and a plastic lens. Therefore the problems caused by the contact sensor are solved by using the noncontact sensor. The noncontact sensor has to move toward the objects and obtain the focus error signal to measure a position of transparent objects. While the internal temperature of the sensor is controlled under ${\pm}0.1^{\circ}$, many trials shows ${\pm}2{\mu}m$ measurement error as excellent performance.