• Proceedings of the Korea Contents Association Conference
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• 2003.11a
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• pp.271-275
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• 2003

In this paper, we propose a method that corrects the geometric distortion of mouth in an image. the method is composed of two steps - detecting key points and correcting geometric distortion. First, key points of lips in source and destination images are found by using lips detection algorithm. Then, the two images are mapped by using affine transformation and information found in first step. In experiment result for various mouths with different geometric distortion, we found that the proposed method have satisfactory efficiency.

• Journal of the Korean Institute of Telematics and Electronics A
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• v.31A no.5
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• pp.50-57
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• 1994

The analysis of the two-tone intermodulation distortion of multistage two-ports with gain and mismatching losses is presented with simplified two-port analyses and statistical viewpoint. The uncertainty obtained from unknown phase angles of the intermodulation distortion signals to the system designer is reduced using stochastic process, hence improving the accuracy of the solution. Based on the dc power dependance of third-order intercept point of each stage, the new efficient method for improving the total intercept point is also suggested with only the relation of dc power and available power gain criteria. Experimental verification on specific amplifiers used for cellular mobile communication comparing predicted and measured intercept points for various power conditions is presented.

• Journal of the Korean Society of Manufacturing Process Engineers
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• v.11 no.5
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• pp.115-120
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• 2012

Metals used orthopedic in human magnetic resonance imaging scan of the metal to be inserted, The information to users about the image distortion is to propose a basis for judgment. Metals used orthopedic on Stainless, Titanium and Clip using ferromagnetic artifacts and distortion of the image were measured. Using Phantom "Effect of Metals used in Orthopedic on Magnetic Resonance ImagingI" pig in a paper subsequently was carried out using the same bone. Experimental results using a pure Titanium is a relatively high diagnostic value was found that.

• Journal of the Korean Institute of Telematics and Electronics B
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• v.31B no.2
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• pp.56-68
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• 1994

The objective of camera calibration is to determine the internal optical characteristics of camera and the three-dimensional position and orientation of camera with respect to the real world. Calibration procedure for computer vision should be automatical, accurate and applicable to general purpose cameras and lenses. In this paper, we present camera calibration method which meets the above requirements. The algorithm is based on the two-stage method which takes into account lens distortion in the second stage. In this paper, the overdetermined nonlinear system is established in terms of the constraints to all directions and our calibration algorithm is proposed which is constructed by using Marquardt iterations and our calibration algorithm is proposed which is constructed by using Marquardt iteration method in solving nonlinear equations. Experimental results indicate that lens distortion should be taken into consideration for the calibration of the general-purpose lens. With 24 calibration points acquired out of 512$\times$512 image, the proposed algorithm came up with average error of less than 1 pixel and showed a higher accuracy over the conventional two-stage method.

• Journal of the Korean Society of Surveying, Geodesy, Photogrammetry and Cartography
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• v.16 no.2
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• pp.327-335
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• 1998

Many kinds of map projection have been used, since this cannot be done without a distortion and seemless representation of the globe. To overcome the continues representation of large digital terrain information by the global coordinate system , to find out the sources of projection error and optimizing method, and to increase the map accuracy, specific map projection researches are needed. In this study, improvements of map projections are suggested for small scale mapping which covering entire Korean peninsula based on theoretical evaluation and limits of current map projection. Furthermore, distortion factors, positional errors, and accuracy increasing method are evaluated.

• Journal of the Institute of Electronics Engineers of Korea TC
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• v.37 no.8
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• pp.45-51
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• 2000

The distortion of an electrical pulse, which has a rise/fall time due to the dispersion and the reflection, on tapered microstrip lines has investigated In time domain. The voltage and current transfer functions are shown for the tapered line. The dispersion distortion obtained by using these trans(or functions are represented for the nonideal square pulse along the triangular, Tchebycheff and exponential tapered lines, and analyzed the influence of the reflection and the frequency dispersion on the distorted voltage wave in the tapered lines. The observed overshoot in front of the distorted wane is caused due to the frequency dispersion and the sustained tail of that comes from the reflection in the tapered line.

• Journal of the Korean Institute of Telematics and Electronics B
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• v.30B no.4
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• pp.44-55
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• 1993

In this paper, we proposed a new optical method for the efficient recognition of Korean characters. There are six filters in the proposed method which employed the concepts of amplitude-modulated phase-only filter(AMPOF) and spatial frequency modulation(SFM). Here, amplitude modulation is used to achieve improved correlation discrimination and SFM is to reduce the number of filters. We also used a simplified synthetic discriminant function(SDF) for distortion invariance of input image. In order to recognize the partial rotation invariant Korean characters, the proposed distortion invariant minimum average correlation energy (MACE) filter is synthesized SFM, partial rotation invariant filter (PRIF), AMPOF and MACE for partial rotation invariance in the frequency domain. The advantage of the proposed filters is to supress the sidelobes of cross correlation peak away from the autocorrelation peak and to produce sharp correlation peaks. We performed simulation and optical experiment for some of Korea characters using the proposed method. The results show that the proposed method has more improved discriminant ability and reduced processing time than the conventional methods.

• Proceedings of the IEEK Conference
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• 2006.06a
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• pp.683-684
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• 2006

본 논문은 비디오기반의 얼굴인식에 있어서 환경의 변화나 왜곡, 노이즈 등으로 발생할 수 있는 부분적인 가림현상(Partial Occlusion)에 대한 처리기법을 제시한다. 인증되는 각 사람은 하나의 Manifold 를 구성하며 각 Manifold 는 m 개의 pose-Manifold 로 구성된다. Pose-Manifold 를 구성하기 위한 학습데이터는 매우 유사한 포즈들로 구성되기 때문에 얼굴을 이루는 영역의 픽셀에 대한 Intensity 의 변화는 크지 않다. 입력되는 이미지의 Intensity 를 학습데이터의 Intensity 의 변화량을 고려한 Intensity Distortion 을 이용하면 Occlusion 이 발생한 영역을 찾을 수 있고, Occlusion 이 발생한 정도에 따라 가중치를 부여할 수 있다. 이렇게 Occlusion 에 따라 영역에 중요도를 다르게 하여 얼굴인식률을 높이고자 한다. 실험에서는 제시하는 Mask 를 사용하지 않았을 경우와 기존에 제시된 알고리즘과의 성능을 비교한다.

• Journal of the Korean Institute of Telematics and Electronics
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• v.24 no.5
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• pp.863-867
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• 1987

When digital image signals are transmitted or stored, they may be usually degraded by impulsive noise such as BSC noise. Though median filtering is a very effective method to reduce the impulsive noise, it brings non-negligible distortion after filtering. Several algorithms have been proposed to reduce such a distortion, but their reconstructed image quality are inadequate in some cases and they have a difficulty in real-time processing. In this paper, an effective filtering algorithm which can not only reduce the noise effectively but also preserve the edges well and lessen the distortion greatly, is presented. The proposed algorithm is an adaptive algorithm of median filter using local statistics, based on the characteristics of human eyes. The adaptive algorithm results shwo performance improvement of up to 3-4 dB over the nonadaptive one.

• Journal of the Korean Institute of Telematics and Electronics B
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• v.32B no.9
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• pp.1171-1180
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• 1995

In this paper, we present a 3-D object recognition system in which the 3-D Hough transform domain is employed to represent the 3-D objects. In object modeling step, the features for recognition are extracted from the CAD models of objects to be recognized. Since the approach is based on the CAD models, the accuracy and flexibility are greatly improved. In matching stage, the sensed image is compared with the stored model, which is assumed to yield a distortion (location and orientation) in the 3-D Hough transform domain. The high dimensional (6-D) parameter space, which defines the distortion, is decomposed into the low dimensional space for an efficient recognition. At first we decompose the distortion parameter into the rotation parameter and the translation parameter, and the rotation parameter is further decomposed into the viewing direction and the rotational angle. Since we use the 3-D Hough transform domain of the input images directly, the sensitivity to the noise and the high computational complexity could be significantly alleviated. The results show that the proposed 3-D object recognition system provides a satisfactory performance on the real range images.