• The Journal of Korean Institute of Communications and Information Sciences
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• v.22 no.10
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• pp.2317-2328
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• 1997

The objective of this paper is to develop an algorithm for a real-time automatic fingerprint recognition system. The algorithm employs the wavelet transform(WT) and the dominat local orientation that derived from the gradient Gaussian(GoG) and coherence in determining the directions of ridges in fingerprint images. By using the WT, the algorithm does not require conventional preprocessing procedures such as smothing, binarization, thining and restoration. For recognition, two fingerprint images are compared in three different ST domains;one that represents the original image compressed to quarter(LL), another that shows vertical directional characteristic(LH), and third as the block that contains horizontal direction(HL) in WT domain. Each block has dominat local orientation that derived from the GoG and coherence. The proposed algorithm is imprlemented on a SunSparc-2 workstation under X-window environment. Our simulation results, in real-time have shown that while the rate of Type II error-Incorrect recognition of two identical fingerprints as the identical fingerprints-is held at 0%, the rate of Type I error-Incorrect recognitionof two identical fingerprints as the different ones-is 2.5%.

• The KIPS Transactions:PartD
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• v.13D no.2 s.105
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• pp.287-292
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• 2006

There are two problems associated with the existing principal component analysis, which is regarded as the most effective in object recognition technology. First, it brings about an increase in the volume of calculations in proportion to the square of image size. Second, it gives rise to a decrease in accuracy according to illumination changes. In order to solve these problems, this paper proposes wavelet transformation and histogram equalization. Wavelet transformation solves the first problem by using the images of low resolution. To solve the second problem the histogram equalization enlarges the contrast of images and widens the distribution of brightness values. The proposed technology improves recognition rate by minimizing the effect of illumination change. It also speeds up the processing and reduces its area by wavelet transformation.

• Proceedings of the Korean Institute of Information and Commucation Sciences Conference
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• 2007.10a
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• pp.901-904
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• 2007

Nowadays, in many fields of medical treatment, we can make an observation and a diagnosis of inward disease without using a surgical operation. As one of them, ultra-sound diagnosis system can be available widely in its cost and size compared with other medical instruments. This system also make it possible for us to see the inner parts of the body in real time harmlessly for a long time. So it can be utilized to inspect the movement of heart or fetus and to diagnose an internal disease of the soft tissues. Ultra-sound images can be generated by the reflexive and scattered wave through the pulse generator and so in ultrasound images there exist inherently many affective noised signals. In this paper, we are to take an noise-restrained image and to extract a more affective regions of the images.

• Journal of the Korean Institute of Telematics and Electronics S
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• v.36S no.10
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• pp.123-131
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• 1999

In this paper, we proposed stereo matching algorithm by dynamic programming with edges emphasized. Existing algorithms show blur generally at depth discontinuities owing to smoothness constraint and non-existence of matching pixel in occlusion regions. Also it accompanies matching error by lackness of matching information in the untextured regions. This paper defines new cost function to make up for the problems occurred to existing algorithms. It is possible through deriving matching of edges in left and right images to be carried out between edge regions anf deriving that in the other regions to be peformed between the other regions. In case of the possibility that edges can be Produced in a large amount, matching between edge information adds weight to cost function in proportion to Path distance. Proposed algorithm was applied to various images obtained by convergent camera model as well as parallel camera model. As the result, proposed algorithm showed improved performance in the aspect of matching error and processing in the occlusion regions compared to existing algorithms. Also it could improve blur especially in discontinuity regions.

• Journal of radiological science and technology
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• v.40 no.2
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• pp.197-203
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• 2017

The purpose of this study was to measure signal to noise ratio (SNR) according to change of equalization from region of interest (ROI) of heart shadow in chest image. We examined images of chest image of 87 patients in a University-affiliated hospital, Seoul, Korea. Chest images of each patient were calculated by using ImageJ. We have analysis socio-demographical variables, SNR according to images, 95% confidence according to SNR of difference in a mean of SNR. Differences of SNR among change of equalization were tested by SPSS Statistics21 ANOVA test for there was statistical significance 95%(p < 0.05). In SNR results, with the quality of distributions in the order of original chest image, original chest image heart shadow and equalization chest image, equalization chest image heart shadow(p < 0.001). In conclusion, this study would be that quantitative evaluation of heart shadow on chest image can be used as an adjunct to the histogram equalization chest image.

• The Journal of Korean Institute of Communications and Information Sciences
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• v.25 no.1B
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• pp.141-147
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• 2000

In the restoration of degraded noisy motion blurred image, we have trade-off problem between smoothing the noise and restoration of the edge region. While the noise is smoothed, die edge or details will be corrupted. On the other hand, restoring the edge will amplify the noise. To solve this problem we propose an adaptive algorithm which uses I- H regularization operator for flat region and Laplacian regularization operator for edge region. Through the experiments, we verify that the proposed method shows better results in the suppression of the noise amplification in flat region, introducing less ringing artifacts in edge region and better ISNR than those of the conventional ones.

• Proceedings of the Korean Institute of Information and Commucation Sciences Conference
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• 2021.05a
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• pp.359-360
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• 2021

The pixel-based processing of an image refers to a process of converting a value of one pixel only depending on the value of the current pixel, regardless of the value of another pixel. Pixel-based processing is used as the most basic operation in many fields such as image conversion, image enhancement, and image synthesis. There are processing methods such as arithmetic operation, histogram smoothing, and contrast stretching. In this paper, in order to clearly distinguish the tidal flat region from the tidal flat image of the west coast taken with a drone, we seek a method to find an efficient outline using pixel-based processing in the boundary detection part of the pre-processing process.

• Journal of the Korean Institute of Telematics and Electronics
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• v.26 no.7
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• pp.132-139
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• 1989

Optical flow is important not only for determining velocity and trajectory of the object but also for image segmentation and 3D information. The gradient-based method is mostly used to compute optical flow form image sequences, but it accomanies smoothing effect of velocity vectors. In this paper, an enhanced algorithm for computing optical flow using scalar edge to restrict is also applied to reduce errors both around motion boundary and in the occlusion region.

• Proceedings of the KSEEG Conference
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• 2002.04a
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• pp.198-200
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• 2002

경제적이며 정확한 3차원 전자탐사 모델링을 위해 위해 Habashy et al. (1993)에 의해 제안된 국소 비선형 근사(localized nonlinear approximation)를 이용하여 전자탐사 모델링 알고리듬을 개발하였다. 전자탐사 수치모델링시 많은 계산시간 및 기억용량을 필요로 하는 Green 텐서 적분을 정확하고 빠르게 계산하기 위해, 단일 미소체를 이용한 공간파수 영역에서의 Green 텐서 적분 알고리듬을 제안하였다. 더욱이 Green 텐서의 송수신 방향 및 상반성을 고려하여 각각의 미소체에 의한 전체 미소체에의 Green 텐서 적분을 한 개의 미소체에 의한 전체 미소체에의 Green 텐서 적분 값으로 구하게 하므로 매우 적은 기억용량 만으로 Green 텐서 적분 행렬을 구성할 수 있어, 역산법에 효과적으로 적용할 수 있다. 이 수치 모델링 알고리듬을 기본으로 하여 평활화 제한을 가한 최소자승 역산 알고리듬을 개발하였다. 이 역산 알고리듬을 지표 전자탐사 및 시추공-지표 전자탐사 등에 적용하여 PC에서도 빠르게 3차원 전자탐사 역산이 수행됨을 보였다.

• Proceedings of the Korean Society of Broadcast Engineers Conference
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• 2022.11a
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• pp.106-108
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• 2022

이미지 기반 3D 형상 복원에 있어서, 이미지에 보이지 않는 폐색(Occlusion) 영역 부분에 대한 정보가 손실되므로 완전한 복원에 어려움이 있으며, 세밀한 텍스쳐(Texture) 표현이 이루어지지 않고 심한 평활화(Smoothing)나 고립된 노이즈 메쉬(Isolated Noise Mesh) 등 구조적 훼손이 발생한다. 주로 깊은 신경망을 이용하여, 음함수(Implicit Function) 기반 방법은 사전훈련이 완료된 보조 신경망들을 전면부에 배치하거나, Hourglass 등 임베딩(Embedding) 아키텍처를 추가하거나, 또는 표면 법선(Surface Normal)과 같은 환시(Hallucination)를 생성하여 신경망에 입력하기도 한다. 이 논문에서는, 인물의 이미지를 입력받아 색상, 머리카락 및 의상을 포함하는 완전 3D 인간 복원 기술들을 조망해본다.