• 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.

• Journal of Institute of Control, Robotics and Systems
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• v.15 no.10
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• pp.1021-1028
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• 2009

In this paper, a location identification for a cleaning robot using a camera shooting forward a room ceiling which kas three point landmarks is introduced. These three points are made from a laser source which is placed on an auto charger. A fisheye lens covering almost 150 degrees is utilized and the image is transformed to a camera image grabber. The widly shot image has an inevitable distortion even if wide range is coverd. This distortion is flatten using an image warping scheme. Several vision processing techniques such as an intersection extraction erosion, and curve fitting are employed. Next, three point marks are identified and their correspondence is investigated. Through this image processing and image distortion adjustment, a robot location in a wide geometrical coverage is identified.

• Journal of Korea Multimedia Society
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• v.22 no.2
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• pp.128-135
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• 2019

This paper presents a deep learning-based object detection method for recognizing vehicles in images acquired through cameras installed on ceiling of underground parking lot. First, we present an image enhancement method, which improves vehicle detection performance under dark lighting environment. Second, we present a new CNN-based multiscale classifiers for detecting vehicles in images acquired through cameras with fisheye lens. Experiments show that the presented vehicle detector has better performance than the conventional ones.

• Journal of Broadcast Engineering
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• v.10 no.1 s.26
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• pp.68-76
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• 2005

We propose a new type of stereoscopic camera system with a zoom lens module to overcome the backlash for the stability of picture matching and the difficulty of zoom control. This system is designed to control a pair of zoom lens with a rotation lever. In this paper, we present the structural characteristics of our proposed system, and verify that there are no image mismatching at acquired stereo images and the zoom in$\cdot$out is easy to control. In our experiments, we achieve good results that a convergence control is very simple and distortion of images is decreased.

• Journal of the Semiconductor & Display Technology
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• v.8 no.4
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• pp.43-48
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• 2009

The aim of this paper is to describe the development of the electron-beam optic analysis algorithm for simulating the e-beam behavior concerned with electrostatic lenses and their focal properties in the micro-column of the multi-beam lithography system. The electrostatic lens consists of an array of electrodes held at different potentials. The electrostatic lens, the so-called einzel lens, which is composed of three electrodes, is used to focus the electron beam by adjusting the voltages of the electrodes. The optics of an electron beam penetrating a region of an electric field is similar to the situation in light optics. The electron is accelerated or decelerated, and the trajectory depends on the angle of incidence with respect to the equi-potential surfaces of the field. The performance parameters, such as the working distances and the beam diameters are obtained by the computational simulations as a function of the focusing voltages of the einzel lens electrodes. Based on the developed simulation algorithm, the high performance of the micro-column can be achieved through optimized control of the einzel lens.

• Journal of the Korean Society of Surveying, Geodesy, Photogrammetry and Cartography
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• v.7 no.2
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• pp.45-51
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• 1989

Lens distortion would produce image displacement, therefore correction of lens distortion is required urgently to improve accuracy of results in photogrammetry. The objective of this study is to find out lens distortion coefficients versus focussing distance on non-metric and metric camera and to investigate propriety of application of lens distortion coefficients to three dimensional analysis. Analytical plumb line method which needs not perform control survey and space resection and requires only one photograph was used in order to get lens distortion coefficients. As the result of this study, the coefficients of radial and tangential distortion change as focussing distance changes, and consequently it is reasonable to apply the eigenvalues of lens distortion coefficients according to focussing distance. When these coefficients were applied to actual measurement, standard errors decreased about 30% or 76% remarkably.

• Applied Microscopy
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• v.36 no.3
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• pp.227-234
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• 2006

To investigate the comparative effect of spherical and aspherical RGP lens were worn during 3 weeks on rabbit's cornea. Four white rabbits were worn right eyes with spherical lens and 4 white rabbits were worn right eyes with aspherical RGP lens. Left eyes were served as control. The rabbits were sacrificed at 3 weeks after fitting and observed morphological changes by scanning electron microscopy and also investigate proliferation rate of the corneal epithelium with RGP wearing. After spherical RGP lens wearing, the epithet layer damaged compared to aspherical lens. The superficial cell layer strip off seriously, cell size significantly changed abnormal. Both spherical and aspherical RGP lens fitting group showed so many bacteria and back surface of lens was found like a fern shape. The aspherical RGP lens original material type was some formal than spherical lens. We thought that these pattern was significantly altered with spherical lens by prohibited transmitter oxygen from atmosphere therefore the epithelium shape was changed. This suggested wearing the aspherical lens might be less physiologic than shperical lens fitting.

• Transactions of the Korean Society of Machine Tool Engineers
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• v.14 no.2
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• pp.14-20
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• 2005

This paper describes a dwell time calculation algorithm for polishing tool path generation in the small toot polishing process of the axis-symmetrical lens. Generally dwell time control in the polishing machines means that small polishing tool stays for a dwell time at the specific surface position to get the expected polishing depth. Polishing depth distribution on an aspherical lens surface consists of the superposition of the local polishing depth at the each dwell position. Therefore, tool path generation needs each dwell time together with tool positioning data during the polishing tool movements on the aspherical lens surface. The linear algebraic equation of removal depth removal matrix and dwell time is formulated. Parametric effects such as the dwell d interval are simulated to validate the dwell time calculation algorithm.

• Journal of the Korean Society for Precision Engineering
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• v.18 no.7
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• pp.65-71
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• 2001

The development process of the polishing system for the aspherical lens mold for opto-electronics industry is described. The system uses the method that polishing tool is scanned on the surface under PC-NC control for the aspherical lens mold. The two axes interpolation of the minimum translation mechanism is applied to give uniform working condition by motion analysis. An aspherical surface is divided into multiple sections and each dwell time is calculated from the polishing rate model based on the Preston equation. As result of form error compensation experiment, initial form error is decreased about 25% while an average value of surface roughness is also reduced successfully from 180nm to 19nm.

• Transactions of the Korean Society of Machine Tool Engineers
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• v.16 no.6
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• pp.163-167
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• 2007

A field emission electron gun including 3 electrodes including one cathode and two anodes is very important for high resolution electron microscope. To have functions to control the initially-emitted electron beam, two anodes act as an electrostatic lens according to equipotential lines by adjusting the spot size, intensity, and working distance. To verify the action of the electron beam by the electrostatic lens by changing several parameters such as electrode shape, displacement and applied voltage to the electrodes, the two lenses were design and simulated and then their performances were analyzed with angular beam intensity(distribution), electrical optic axis variation and their stability.