• Proceedings of the KSME Conference
• /
• 2007.05a
• /
• pp.461-466
• /
• 2007

There has been a great interest in printing technology as a low cost and mass production method for the application of printed electronics such as printed TFT, solar cell, RFID Tag, printed battery, and so on. In this study, apparatuses of gravure-offset printing are developed for fine line-width/gap printing and examining pattern distortion occurred in gravure-offset printing process. The fine line-width/gap pattern shows that it is possible to make around 20 micro-meter line-width/gap printing patterns. Pattern distortion is modeled, and the amount and shape of the distortion are calculated by using commercial FEM code. The roll-to-roll printing system under development consists of unwinder/rewinder, two printing units, one coating unit, drying units, guiding unit, vision system, and other auxiliary devices. For multi-layer printing, the system is designed to be capable of printing two different materials.

• The Journal of Korean Institute of Communications and Information Sciences
• /
• v.34 no.10B
• /
• pp.1111-1116
• /
• 2009

In this paper, we discuss distortion-tolerant pattern recognition using computational integral imaging reconstruction. Three-dimensional object information is captured by the integral imaging pick-up process. The captured information is numerically reconstructed at arbitrary depth-levels by averaging the corresponding pixels. We apply Fisher linear discriminant analysis combined with principal component analysis to computationally reconstructed images for the distortion-tolerant recognition. Fisher linear discriminant analysis maximizes the discrimination capability between classes and principal component analysis reduces the dimensionality with the minimum mean squared errors between the original and the restored images. The presented methods provide the promising results for the classification of out-of-plane rotated objects.

• Journal of the Semiconductor & Display Technology
• /
• v.9 no.2
• /
• pp.55-60
• /
• 2010

Ink transfer process from the printing roll to the moving web was investigated using a CFD technique for the application in R2R printed electronics. In line with the requirement that the web handling speed needs to be increased further for the cost competitiveness, the effects of web moving velocity with relatively complex roll patterns were analyzed. To make the present analysis more realistic, the numerical geometry and the ink properties were selected to match those of the real printing production system. Our numerical results showed that both web handling speed and complex printing-roll patterns influenced the shape of the transferred ink. As the web moving speed approaches towards 30mpm, a significant distortion of the shape of the transferred ink occurred. In the range of pattern width smaller than 100 microns, a phase distortion was also found to occur in all the printing-roll patterns considered in the present work but the ratio of the phase distortion to the line width gets smaller as the width becomes smaller. Thus, the web handling speed and the shape of printing-roll pattern will be important elements for the better printing quality under 100 micron line width range.

• The Journal of Korean Institute of Electromagnetic Engineering and Science
• /
• v.20 no.7
• /
• pp.625-630
• /
• 2009

In this paper, we introduce the analysis and counter-measure of signal distortion of search radar equipped on the ship. Using ShipEDF program, the search radar's main antenna and ship structures are modeled in the view of electromagnetism. Ray tracing method is used for analysis of the search radar's radiation patterns in free space and ship condition. From analyzed radiation patterns, we can conclude that the search radar's signal distortion is due to radiation pattern distortion. We also analyze the surface current distribution of the mast to propose the counter-measure to reduce electro-magnetic field reflection of mast.

• The Journal of Korean Academy of Prosthodontics
• /
• v.38 no.1
• /
• pp.26-37
• /
• 2000

The purpose of this study was to investigate the effect that three resin indexing materials had on the distortion of split cast in the procedures of solder indexing and block fabrication. The specimen had two cylinders and connecting bar Two cylinders were a reference cylinder and a test cylinder that were machined precisely and placed on metal base. The total of specimens were 30 and they were divided into 3 groups according to the resin indexing materials : Acrylic $solder^{(R)}$, G-C Pattern $resin^{(R)},\;Z-100^{(R)}$. The relative coordinates (X, Y, Z) of centroids of both cylinders were measured by using 3-D cool dinates measuring machine. The value of indexing distortion was obtained after application of indexing material, and the value of the block distortion was obtained after fabrication of soldering block, and the value of total distortion was a value sum of indexing distortion and block distortion. Intercentroidal linear distortion ${(\sqrt{X^{'2}+Y^{'2}+Z^{'2}}-{\sqrt{X^2+Y^2+Z^2)}$ and global distortion $(\sqrt{{(X^'-X)}^2+{(Y^'-Y)}^2+{(Z^'-Z)}^2}$ were calculated from data of coordinates of centroids at each measuring stages. The results of this study were as belows ; 1. The intercentroidal distance between the split casts was reduced by indexing distortion and increased by block distortion. 2. The indexing global distortion between the split casts was smaller than block global distortion. 3. The intercentroidal linear distortion and the global distortion were no significant difference between indexing materials.

• The Journal of the Institute of Internet, Broadcasting and Communication
• /
• v.18 no.4
• /
• pp.49-53
• /
• 2018

Parabolic offset antenna is widely used for wireless communication system. The general structure of parabolic offset antenna system is composed of supporting stand and RF devices under parabolic reflector. However sidelobe distortion in gain pattern is occurred by supporting stand and RF devices. Depending on position of subsidiary devices, angle of sidelobe distortion can be changed. In this paper we describe method for sidelobe distortion suppression using raytracing. We calculate 3D vector for sidelobe distortion suppression zone by raytracing method and compare when subsidiary device is in sidelobe distortion suppression zone or not. By comparison, we show method for parabolic antenna sidelobe distortion suppression.

• Proceedings of the Korean Society of Machine Tool Engineers Conference
• /
• 1997.10a
• /
• pp.225-229
• /
• 1997

This paper describes the camera calibration based-neural network with a camera modeling that accounts for major sources of camera distortion, namely, radial, decentering, and thin prism distortion. Radial distortion causes and inward or outward displacement of a given image point from its ideal location. Actual optical systems are subject to various degrees of decentering, that is, the optical centers of lens elements are not strictly collinear. Thin prism distortion arises from imperfection in lens design and manufacturing as well as camera assembly. It is our purpose to develop the vision system for the pattern recognition and the automatic test of parts and to apply the line of manufacturing. The performance of proposed camera calibration is illustrated by simulation and experiment.

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

• The Transactions of The Korean Institute of Electrical Engineers
• /
• v.62 no.9
• /
• pp.1270-1275
• /
• 2013

A lot of research about camera calibration and lens distortion for wide-angle lens has been made. Especially, calibration for fish-eye lens which has 180 degree FOV(field of view) or above is more tricky, so existing research employed a huge calibration pattern or even 3D pattern. And it is important that calibration parameters (such as distortion coefficients) are suitably initialized to get accurate calibration results. It can be achieved by using manufacturer information or lease-square method for relatively narrow FOV(135, 150 degree) lens. In this paper, without any previous manufacturer information, camera calibration and barrel undistortion for fish-eye lens with over 180 degree FOV are achieved by only using one calibration pattern image. We applied QR decomposition for initialization and Regularization for optimization. With the result of experiment, we verified that our algorithm can achieve camera calibration and image undistortion successfully.

• Proceedings of the IEEK Conference
• /
• 2002.07b
• /
• pp.1268-1271
• /
• 2002

The major threat of geometric manipulations is that they change the positions of watermarks, therefore the detection process fails to extract watermark properly. Since they cause the same effects on the host image as watermarks simultaneously, evaluating the distorted host image can be helpful to measure the nature of distortions. In this paper, we propose a geometrical distortion-resilient watermarking algorithm based on this property. Firstly we evaluate the orientation of a host image by filtering it with directional Gabor kernels, then we insert embedding pattern aligned to the estimated orientation. In its detection step, we evaluate the orientation again by Gabor filtering, then simply project and average the projected value to obtain a 1-D projection average pattern. Finally, auto-correlation function of the 1-D projection average pattern identifies periodic peaks. Analysed are experimental results against geometrical attacks including aspect ratio changes.