• The Journal of the Korea institute of electronic communication sciences
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• v.14 no.6
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• pp.1053-1060
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• 2019

The satellite antenna for collecting information is mainly classified into reflector antenna, lens antenna, and phased array antenna. Among them, the phased array antenna with the excellent antenna pattern control performance for a multi-beam system is frequently used. Although the terrestrial signal information collection based on the satellite is not much effected geographically, it requires the accurate angle-of-arrival (AOA) information of the interesting signal. In this paper, we discuss the characteristics and the advantages/disadvantages of the antenna array shape employed in the phased array antenna. In addition, we present the Cascade AOA estimation algorithm based on a square array antenna mounted on the satellite receiver, and show the performance evaluation results through the computer simulation.

• Korean Journal of Optics and Photonics
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• v.5 no.3
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• pp.364-371
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• 1994

Real-time MTF measuring system for testing microlens arrays with a linear CCD array is developed. The spread function of slit image that is relayed and magnified by a microscopic object lens can be measured at several times in a second. The signal uniformity and MTF of CCD is also calibrated. The experimental result of micro lens arrays developed for contact image sensor is presented.sented.

• Korean Journal of Optics and Photonics
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• v.30 no.3
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• pp.94-100
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• 2019

The near-field subwavelength squint-less focusing system of a phased array antenna is designed and demonstrated by numerical simulation. The Huygens-Fresnel principle is applied to numerical simulation for calculation of the phased array antenna at microwave frequency. It was shown that beam squinting can be eliminated, utilizing true-time optical delay lines based on a chirped fiber grating in the proposed system. Furthermore, subwavelength focusing with high numerical aperture can be achieved by considering the fact that the array elements of the phased-array antenna can be treated as diffractive elements in an optical lens system. Also, side lobes can be suppressed by decreasing the distance between element antennas to less than half of the wavelength.

• Proceedings of the Optical Society of Korea Conference
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• 2007.02a
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• pp.135-136
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• 2007

• Journal of Welding and Joining
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• v.29 no.1
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• pp.29-32
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• 2011

• Journal of IKEEE
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• v.22 no.3
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• pp.858-861
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• 2018

In this paper, we propose the development of a small $360^{\circ}$ oral scanner lens module. The proposed small $360^{\circ}$ oral scanner lens module consists of a small $360^{\circ}$ high resolution(4MegaPixel) lens optical system, a 15mm image sensor unit, and a small $360^{\circ}$ mouth scanner lens external shape. A small $360^{\circ}$ high resolution lens optical system produces a total of nine lenses, the outer diameter of the lens not less than 15mm for use by children through the ages of adulthood. Light drawn by a small $360^{\circ}$ high resolution lens optical system is $90^{\circ}$ flexion so that image images are delivered to image sensors. The 15mm image sensor unit sends the converted value to the ISP(Image Signal Processor) of the embedded board after an image array through the column and the row address of the image sensor. The small $360^{\circ}$ mouth scanner lens outer shape was designed to fix the race to the developed lens. Results from authorized testing agencies to assess the performance of proposed small $360^{\circ}$ oral scanner lens modules, The optical resolving power of $360^{\circ}$ lens was more than 30% at 150 cycles/mm, $360^{\circ}$ lens angle was $360^{\circ}$ in vertical direction, $42^{\circ}{\sim}85^{\circ}$ in vertical direction, and lens distortion rate was 5% or less. It produced the same result as the world's highest level.

• Proceedings of the Korean Institute of Information and Commucation Sciences Conference
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• 2012.10a
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• pp.1012-1014
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• 2012

Integral imaging is considered as a next-generation 3D display which can display 3d imaging in space using lens array. The performance of integral imaging systems depends on several factors including display panel, lens array, imaging devices and so on. In this paper, we develop a unifying framework to evaluate the resolution of integral imaging systems under fixed resource constraints. The proposed framework enables one to optimize the system performance. To show the feasibility of the proposed method, we carry out Monte Carlo simulations based on this framework and present the results.

• Journal of Korean Ophthalmic Optics Society
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• v.6 no.1
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• pp.55-58
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• 2001

The rigid gas permeable(RGP) contact lens has nearly side effect on the cornea. So that, this lens has used the clinical reflective correction of the eye. This study have used several methods for research the fine internal structure on the RGP contact lens by scanning electron microscopy. The results have indicated that the postfixation of 1% $OsO_4$ and tannic acid is responsible for a fine structure in the internal plane of RGP contact lens. These internal surface of contact lens appeared the several shape of the hole of the stereo shape form with arrangement of round form. But, on the contact lens with non-postfixation, the stereo shape have not present and the boundary of the vesicle have not clear. Maybe, these results suggest that the fixation methods have effect on the morphological characters of materials on the RGP contact lens.

• The Journal of Korean Institute of Communications and Information Sciences
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• v.9 no.3
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• pp.127-131
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• 1984

The IOVMM(Incoherent Optical Vector Matrix Multiplier) is constructed, which can process much information very fast by incogerent light source, and its experimental results are compared with the theoretical values. The input vector and matirx elements are limited to the positive number in this paper. The input vector is made by the LED array and the matrix is encoded on the film by the area modulation method. The result of the vector-matrix multiplication is detected by the photodiode array through the lens system. The analog multiplexer is used for looking at output signal on one channel.

• Korean Journal of Optics and Photonics
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• v.18 no.1
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• pp.24-30
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• 2007

We have studied depth conversion of a reconstructed image by means of recombination of the elemental images in the integral imaging system for 3D display. With the recombination, depth conversion to the pseudoscopic, the orthoscopic, the real or the virtual as well as to arbitrary depth without any distortion is possible under proper conditions. The conditions on the recombinations for the depth conversion are theoretically derived. The reconstructed images using the converted elemental images are presented.