• 전자공학회논문지B
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• 제33B권3호
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• pp.88-95
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• 1996

Recently, the use of color data is growing fast in the area of image processing. To represent full resolution image on a limited output device, image has to be quantized an dithered. So, many dithering techniques are foundd in the printing. In this paper, we propose nonlinear quantization to consider the overlapping phenomena of neighboring printing dots and modified dot diffusion algorithm to compensate the color degradation produced in the quantization process. In the modified dot-diffusion quantization errors to be diffused are adjusted to improve both image blur and color change produced in the dot diffusion. The printed image obtained by the proposed color dithering method has higher visual quality an less color degradation than the images by conventional printing method.

• 대한원격탐사학회:학술대회논문집
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• 대한원격탐사학회 2008년도 International Symposium on Remote Sensing
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• pp.159-162
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• 2008

This paper presents a modified mean curvature diffusion filter to smooth speckle noise in images. Mean curvature diffusion filter has already shown good results in reducing noise in images while preserving fine details. In the mean curvature diffusion, the rate of smoothing is controlled by the local value of the diffusion coefficient chosen to be a function of the local image gradient magnitude. In this paper, the diffusion coefficient is modified to be controlled adaptively by local image surface slope and heterogeneity. The local surface slope contributes to preserving details (e.g.edges) in image and the local surface heterogeneity helps the smoothing filter consider the amount of noise in both edge and non-edge area. The proposed filter's performance is demonstrated by quantitative experiments using speckle noised aerial image and TerraSAR-X satellite image.

• Nuclear Engineering and Technology
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• 제52권10호
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• pp.2328-2333
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• 2020

The filter technique was applied to noise images, as noise is the significant factor that cause poor image quality due to lower photon counting. The purpose of this study is to confirm that image quality can be improved using the median modified Wiener filter (MMWF) technique; this is achieved via a National Electrical Manufacturers Association International Electrotechnical Commission body phantom with four large spheres that are filled with the ^99mTc radioisotope when evaluating the image quality. Conventional filters such as Wiener, Gaussian, and median filters were designed, and signal to noise ratio, coefficient of variation, and contrast to noise ratio were used as the evaluation parameters. The improvement in the image quality was in the following order, from the least to the highest improvement, in all cases: Wiener filter, Gaussian filter, median filter, and the MMWF technique. The results show that the image quality was improved from 20.6 to 65.5%, 7.4-40.3%, and 12.7-44.7% for the SNR, COV, and CNR values, respectively, when using the MMWF technique, compared with the use of conventional filters. In conclusion, our results demonstrated that the MMWF technique is useful for reducing the noise distribution in gamma camera images.

• 대한전자공학회:학술대회논문집
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• 대한전자공학회 2002년도 ITC-CSCC -1
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• pp.682-685
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• 2002

In this paper, we defined necessary operations and functional blocks of a multiplexer for 3-D video systems and present our multiplexer design. We adopted the ITU-T's recommendation(H.222.0) to define the operations and functions of the multiplexer and explained the data structures and details of the design for multiview image processing. The data structure of TS(Transport Stream) and PES (Packetized Elementary Stream) in ITU-T Recommendation H.222.0 does not fit our multiview image processing system, because this recommendation is fur wide scope of transmission of non-telephone signals. Therefore, we modified these TS and PES stream structures. The TS is modified to DSS(3D System Stream) and PES is modified to SPDU(DSS Program Data Unit). We constructed the multiplexer through these modified DSS and SPDU. The number of multiview image channels is nine, and the image class employed is MPEG-2 SD(Standard Definition) level which requires a bandwidth of 2∼6 Mbps. The required clock speed should be faster than 54(= 6 ${\times}$ 9)㎒ which is the outer interface clock speed. The inside part of the multiplexer requires a clock speed of only 1/8 of 54㎒, since the inside part of the multiplexer operates by the unit of byte. we used ALTERA Quartus II and the FPGA verification for the simulation.

• 한국정보과학회논문지:소프트웨어및응용
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• 제29권12호
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• pp.940-946
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• 2002

본 논문에서는 변형된 칼라 코렐로그램(Color Correlogram)을 이용한 영상검색 방법을 제안한다. 제안한 방법은 영상 내의 같은 칼라를 가지는 영역의 크기 변화에 강인하게 영상을 검색하기 위해, 영상에서 얻어진 칼라 코렐로그램의 오토-코렐로그램(auto-correlogram)과 크로스-코렐로그램(cross-correlogram) 영역을 각각 정규화하여 변형된 칼라 코렐로그램을 얻는다. 그리고 영상검색을 위한 유사도 측정시, 오토-코렐로그램에 가중치를 크로스-코렐로그램 영역보다 작게 준다. 제안한 방법은 칼라 코렐로그램의 정보를 효과적으로 사용함으로써, 영상검색 성능을 높일 수 있다. 실험을 통해 제안한 방법이 기존의 칼라 코렐로그램을 이용한 방법보다 효과적으로 영상을 검색할 수 있음을 확인하였다.

• Communications for Statistical Applications and Methods
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• 제16권2호
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• pp.277-286
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• 2009

영상정합은 동일한 장면에 대해서 서로 다른 시간 혹은 특성의 센서로부터 서로 다른 위치 에서 얻는 영상들의 공간적 대응관계를 찾는 과정이다. 본 논문에서는 동일 환자에게 촬영한 뇌 MR과 CT영상간의 상이한 공간좌표계의 차이를 보정하기 위 한 강인한 정합방법을 소개한다. 두 영상의 명암도에 대한 결합 히스토그램으로부터 계산된 개선된 조건부 엔트로피(MCE: Modified Conditional Entropy)를 이용하여 최대인 위치로 정합을 수행하고, 3차원 볼륨 렌더링 기법을 이용하여 정합된 영상을 가시화한다.

• 한국진공학회:학술대회논문집
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• 한국진공학회 2009년도 제38회 동계학술대회 초록집
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• pp.472-472
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• 2010

The tomography has played a key role in tokamak plasma diagnostics for image reconstruction. The Phillips-Tikhonov (P-T) regularization method was attempted in this work to reconstruct cross-sectional phantom images of the plasma by minimizing the gradient between adjacent pixel data. Recent studies about the comparison of the several tomographic reconstruction methods showed that the P-T method produced more accurate results. We have studied existing Laplacian matrix used in Phillips-Tikhonov regularization method and developed modified Laplacian matrix (Modified L). The comparison of the reconstruction result by the modified L and existing L showed that modified L produced more accurate result. The difference was significantly pronounced when a portion of plasma was reconstructed. These results can be utilized in the Edge Plasma diagnostics; especially in divertor diagnostics on tokamak a large impact is expected. In addition, accurate reconstruction results from received data in only one direction were confirmed through phantom test by using P-T method with modified L. These results can be applied to the tangentially viewing pin-hole camera diagnostics on tokamak.

• 대한원격탐사학회:학술대회논문집
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• 대한원격탐사학회 2003년도 Proceedings of ACRS 2003 ISRS
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• pp.1337-1339
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• 2003

In this article, a new remote sensing image fusion model based on modified Kohonen networks is given. And a new fusion rule based on modified voting rule was established. Select Shaoxing City as the study site, located at Zhejiang Province, P.R.China. The fusion experiment between Landsat TM data (30m) and IRS-C Pan data (5.8m) was performed using the given fusion method. The fusion results show that the new method can gain better result in apply ing to the lower hill area, and the whole classification accuracy was 10% higher than the basic Kohonen method. The confusion between the woodlands and the waterbodies was also diminished.

• International Journal of Concrete Structures and Materials
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• 제19권1E호
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• pp.41-48
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• 2007

Addition of latex to concrete is known to increase its durability and permeability. The purpose of this study is to analyze air void systems in latex-modified concretes using a reasonable and objective method of image analysis with such experimental variables as water-cement (w/c) ratios, latex contents (0%, 15%) and cement types (ordinary portland cement (OPC), high-early strength (HES) cement and very-early strength (VES) cement). The results are analyzed by spacing factor, air volume (content) after hardening, air void distribution and structure. Additionally, air void systems and permeability of latex-modified concrete (LMC) are compared by a correlation analysis. The results are as follows. The LMC of the same w/c ratio showed better air entraining (AE) effect than OPC with AE water reducer. The VES-LMC showed that the quantity of entrained air below $100{\mu}m$ increased more than four times. For the case of HES-LMC, microscopic entrained air between the range of 50 to $500{\mu}m$ increased greater than 7 times even in the absence of anti-foamer. Although spacing factor was measured rather low, the permeability of latex-modified concrete was good. It is construed that air void system does not have a considerable effect on the property of latex-modified concrete, but latex film (membrane) has a definite influence on the durability of LMC.

• 제어로봇시스템학회논문지
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• 제9권10호
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• pp.774-781
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• 2003

The important factors that cause position error in X-Y robot are inertial force, frictions and spring distortion in screw or coupling. We have to estimate these factors precisely to correct position errors, Which is very difficult. In this paper, we makes systems to inspect metal stencil which is used to print solder paste on pads of SMD of PCB with low precision X-Y robot and vision system. To correct position error that is caused by low precision X-Y robot, we defines position error vector that is formed with position of objects that exist in reference and camera image. We apply MHT(Modified Hough Transformation) for the aim of determining the dominant position error vector. We modify reference image using extracted dominant position error vector and obtain reference image that is the same with camera image. Effectiveness and performance of this method are verified by simulation and experiment.