• 대한원격탐사학회:학술대회논문집
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• 대한원격탐사학회 2006년도 춘계학술대회 논문집
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• pp.275-278
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• 2006

본 연구는 전정색(panchromatic) 고해상도 위성영상을 이용하여 산화피해림과 비산화림을 대상으로 수종별로 구분하여 조사하였다. 제안된 방법은 회색단계 공발생 행렬(Gray Level Co-occurrence Matrix, GLCM)을 통하여 생성된 질감 영상(textural images)과 웨이블릿 분해 영상(wavelet decomposition images)의 융합을 실시하여 질감 영상에서 추출될 수 있는 정보와 웨이블릿 분해를 통해 얻을 수 있는 정보를 획득하고자 하였다. 그 결과로 동일 수종을 형성하는 임반이나 산화피해 정도가 유사한 산림의 경우 영상의 밝기값의 분포가 일정한 범위 내에서 형성되어 수종 분류 및 산화피해 등급의 구분이 가능했으나, 영상 내 경계효과(edge effect) 현상은 일부 영상에서 나타났다.

• 제어로봇시스템학회:학술대회논문집
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• 제어로봇시스템학회 2001년도 ICCAS
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• pp.55.5-55
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• 2001

The MST (Minimum Spanning Tree) matching algorithm had been used for searching the part accord points extracted from the gray level fingerprint image. The method, however, had some limitations. To obtain the relationship between enrolled and inputted fingerprint, the MST was used to generate the tree graph that represent the unique graph for given fingerprint data. From the graph, the accord points are estimated. However, the shape of the graph highly depends on the positions of the minutiae. If there are some pseudo minutiae caused by noise, the shape of the graph will be different In this paper, to overcome the limitations of the MST, we proposed CRM (Center of Rotation Method) algorithm that found the true part accord points. The proposed method is based on the assumption ...

• 제어로봇시스템학회논문지
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• 제4권4호
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• pp.499-505
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• 1998

In developing an automated surface inspect algorithm, we have designed a hierarchical classifier using neural network. The defects which exist on the surface of cold mill strip have a scattering or singular distribution. We have considered three major problems, that is preprocessing, feature extraction and defect classification. In preprocessing, Top-hit transform, adaptive thresholding, thinning and noise rejection are used Especially, Top-hit transform using local minimax operation diminishes the effect of bad lighting. In feature extraction, geometric, moment, co-occurrence matrix, and histogram ratio features are calculated. The histogram ratio feature is taken from the gray-level image. For defect classification, we suggest a hierarchical structure of which nodes are multilayer neural network classifiers. The proposed algorithm reduced error rate by comparing to one-stage structure.

• 대한기계학회:학술대회논문집
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• 대한기계학회 2008년도 추계학술대회A
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• pp.412-417
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• 2008

In a traditional topology optimization method, material properties are usually distributed by finite element density and visualized by a gray level image. The distribution method based on element density is adequate for a great mass of 2-D topology optimization problems. However, when it is used for 3-D topology optimization, it is always difficult to obtain a smooth model representation, and easily appears a virtualconnect phenomenon especially in a low-density domain. The 3-D structural topology optimization method has been developed using the node density instead of the element density that is based on SIMP (solid isotropic microstructure with penalization) algorithm. A computer code based on Matlab was written to validate the proposed method. When it was compared to the element density as design variable, this method could get a more uniform density distribution. To show the usefulness of this method, several typical examples of structure topology optimization are presented.

• 한국멀티미디어학회:학술대회논문집
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• 한국멀티미디어학회 2000년도 추계학술발표논문집
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• pp.262-265
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• 2000

영상에서의 경계선추출은 영상의 강도의 변화를 이용한 경계영역의 가시화 기법이므로 gray level 영상이 가지는 강도를 이용하여 에지를 찾을 수 있다. 뇌 영상에는 MRI 영상과 같이 해부학적인 정보가 큰 영상과, PET 영상같이 perfusion으로 분석해야 할 영상이 있는데 그 경계가 뚜렷한 MRI 영상과 달리 PET 뇌 영상은 영상의 특성상 경계영역의 구분이 모호한 실정이다. 본 논문에서는 이러한 영상의 특성에 따라 뇌 영상에서 영상 강도에 대해 등분할을 한 후 vectorgram에서 magnitude의 영역을 선택하여 영상을 분할 하였다. 그리고 PET 와 MRI영상과 현미경 영상에 대한 결과를 비교하였다. Vertcrgram은 에지정보를 가지는 영상에 대해 벡터요소를 그래프화 한 것으로 방향성에 대한 평가를 통해 영역 분할을 하였다. 이러한 PET 영상의 2차원 분할 방법은 3차원 PET 영상 분석에 응용될 수 있을 것이다.

• 한국항행학회논문지
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• 제9권2호
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• pp.170-176
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• 2005

본 논문에서 제안한 방법은 웨이블릿 변환을 사용하여 디지털 영상을 주파수 공간으로 변환시킨 후 워터마킹하는 알고리즘을 제안한다. 비가시성을 고려하여 고주파 영역을 국부 블록으로 나누어 각 블록의 대조 감도와 텍스처 감도를 계산하고, 각 계수블록에 워터마크를 삽입 시 블록 특성에 따라 가중치를 달리 하였다. 실험결과, 인간의 시각 시스템을 적용하여 워터마크를 삽입함으로써 워터마크의 강인함과 비가시성을 향상시켰다.

• 한국산업융합학회 논문집
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• 제7권1호
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• pp.19-24
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• 2004

An experimental investigation was performed to study the characteristics of laminar water flow in a horizontal circular tube by using liquid crystal. A simultaneous measurement technique has been employed to measure the velocity field in a two-dimensional cross section of fluid flow. This study found the velocity distributions for Re = 1,594 ~ 2,510 along longitudinal sections and the results appear to be physically reasonable. To determine some characteristics of the laminar flow, 2D PIV technique is employed for velocity measurement by using liquid crystal in water. The experimental rig was manufactured from an acryle tube. The test tube diameter of 25mm, and a length of 1200mm. The used algorithm is the gray level cross-correlation method by using Kimura et al. in 1986.

• 대한의용생체공학회:학술대회논문집
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• 대한의용생체공학회 1995년도 춘계학술대회
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• pp.49-53
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• 1995

In this paper, we classify between the chromosome and blood cell, and find the location of chromosome. First, the gray level images be the binary images using the threshold method. Then, the spot noises are removed by the morphological filtering. Features are obtained using the updated Run length(RL) coding and are classified using the Bayes decision rule. The performances of classification are 83.3% in chromosome and 93.3% in blood cell. Because each sub-images ($256{\times}256$) is obtained from the full image($512{\times}512$), we realize the location of chromosome if we get the corrected chromosome classifications.

• 대한전자공학회:학술대회논문집
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• 대한전자공학회 2002년도 하계종합학술대회 논문집(4)
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• pp.45-48
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• 2002

In this paper, we propose an iris recognition system using Homogeneous Texture descriptor of MPEG-7 standard. The texture of iris is generally used in iris recognition system. We segment the pupil with Hough transform and the boundary of iris with it's gray level difference between the white of the eye. To extract Homogeneous Texture descriptor, this iris image is transformed into polar coordinates. The extracted descriptor is then compared with the reference in DB. If their distance is larger than threshold, they are recognized as different iris. Test results will show that Homogeneous Texture descriptor can be a good measure for iris recognition system.

• 전기학회논문지
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• 제59권7호
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• pp.1340-1345
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• 2010

FRC(Frame Rate Control) has been applied to the monitor and TV product as part of cost-saving in many flat panel display manufacturers. As FRC can represent the same number of gray scale level with bits of a smaller amount than bits of the input image data, it is widely used. However, FRC causes visual artifacts by using repeatedly pre-designed the FRC unit size of block pattern in display devices. Therefore, this paper analyzes the cause of the visual artifacts. And in order to improve them, it proposed the pattern arrangement of FRC unit blocks through frame rolling method as analytic solution for the first time. So, we could embody causes of FRC noise. Using the proposed structure, more robust pattern to FRC noise will be designed.