• Journal of the Korean Institute of Intelligent Systems
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• v.19 no.6
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• pp.787-795
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• 2009

This paper presents a histogram equalization based on the logistic function for enhancing the quality of images. The histogram equalization is a simple and effective spatial processing method that it enhances the quality by adjusting the brightness of image. The logistic function that is a nonlinear transformation function is applied to adaptively enhance the brightness of the image according to its intensity level frequency. We propose a flexible and asymmetrical logistic function by only using the intensity level with maximum frequency and the maximum intensity level in an histogram, and the total number of pixels. The proposed function excludes both the computation load of an exponential function and the heuristic setting of an optimal parameter values in the traditional logistic function. The proposed method has been applied for equalizing many images with a different resolution and histogram distribution. The experimental results show that the proposed method has the superior enhancement performances and the faster equalizing speed compared with the traditional histogram equalization and the adaptively modified histogram equalization, respectively. And the proposed histogram equalization can be used in various multimedia systems in real-time.

• Plant Biotechnology Reports
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• v.4 no.2
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• pp.129-138
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• 2010

An efficient transformation system for high-throughput functional genomic studies of kiwifruit has been developed to overcome the problem of necrosis in Actinidia arguta explants. The system uses Agrobacterium tumefaciens strain EHA105 harbouring the binary vector pART27-10 to inoculate leaf strips. The vector contains neomycin phosphotransferase (nptII) and ${\beta}$-glucuronidase (GUS) (uidA) genes. A range of light intensities and different strengths of Murashige and Skoog (MS) basal salt media was used to overcome the problem of browning and/or necrosis of explants and calli. Callus browning was significantly reduced, resulting in regenerated adventitious shoots when the MS basal salt concentration in the culture medium was reduced to half-strength at low light intensity ($3.4\;{\mu}mol\;m^{-2}\;s^{-1}$) conditions. Inoculated leaf strips produced putative transformed shoots of Actinidia arguta on half-MS basal salt medium supplemented with 3.0 $mg\;l^{-1}$ zeatin, 0.5 $mg\;l^{-1}$ 6-benzyladenine, 0.05 $mg\;l^{-1}$ naphthalene acetic acid, 150 $mg\;l^{-1}$ kanamycin and 300 $mg\;l^{-1}$ $Timentin^{(R)}$. All regenerated plantlets were deemed putativ transgenic by histochemical GUS assay and polymerase chain-reaction analysis.

• Journal of Korea Multimedia Society
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• v.7 no.8
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• pp.1046-1057
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• 2004

An image enhancement method using both homomorphic transformation and multiscale decomposition is proposed. The original image is first transformed to homomorphic domain by taking the logarithm, is then separated to multiscales. These multiscales are combined with weighting. The combined signal is exponentially transformed back into intensity domain. In homomorphic domain, the magnitude control of low frequency component make change the dynamic range, and the magnitude control of the other frequency components contribute to enhancement of the contrast. The "${\AA}$ trous" algorithm, which has a simple and efficient scheme, is used for multiscale decomposition. The performance of proposed method is verified by simulation.

• Journal of the Korean Society of Surveying, Geodesy, Photogrammetry and Cartography
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• v.28 no.2
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• pp.281-287
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• 2010

This study compares transformation algorithms for co-registration of terrestrial laser scan data. Pair-wise transformation which is used for transformation of scan data from more than two different view accumulates errors. ICP algorithm commonly used for co-registration between scan data needs initial geometry information. And it is difficult to co-register simultaneously because of too many control points when managing scan at the same time. Therefore, this study perform global registration technique using matching points. Matching points are extracted automatically from intensity image by SIFT and global registration is performed using GP analysis. There are advantages for operation speed, accuracy, automation in suggested global registration algorithm. Through the result from it, registration algorithms can be developed by considering accuracy and speed.

• Transactions of Materials Processing
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• v.16 no.5 s.95
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• pp.348-353
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• 2007

The propagation of a macro-scale crack and the accompanying transformation zone around it was visualized in an Y-TZP ceramic using a mechano-luminescence (ML) technique. The technique allows realistic fractures that take place catastrophically in actual applications to be realistically stimulated. Unlike conventional quasi-static R-curves, the ML technique on a relatively fast time frame permitted a so-called quasi-dynamic R-curve in the crack speed range from 50 to 140 m/sec. to be measured. Effective toughening then commenced and the applied stress intensity factor increased to 27 $MPa{\sqrt{m}}$. The transformation zone height obtained from the ML observations was in good agreement with that predicted by the Marshall model, and coincided with previously observed results for quasi-static conditions by Raman spectorscopy and x-ray analysis.

• Journal of Photoscience
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• v.8 no.1
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• pp.9-12
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• 2001

The photoisomerization behavior of benzylideneacetophenones, known as chalcones, was studied. We synthesized the chalcone derivatives that have ether groups at 4 and 4＇ positions. Due to the electron donating ability of the ether oxygen, the bond order of the single bond between two phenyl ring of the chalcone strengthened, which eventually increased the rotational barrier of the single bond. The rotational barrier of the single bond is about 20-22 kcal/mole. Thermal recovery of this process took about 1 min. The UV-visible spectra of these chromophores exhibit two characteristic absorption peaks at 276 nm and 340 nm. The relative intensity of the peaks varies depending on the alkyl chain length of the substituent. Photo-irradiation with the 365 nm light monotonously decreases the 340 nm peak. However, the photo-irradiation with 254 nm light induce two competing processes and produced rather complicated absorption profile.

• Journal of Electrical Engineering and information Science
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• v.3 no.3
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• pp.330-335
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• 1998

In this paper, a new light-value approaching method to enhance a color image by excluding the effect of incident illumination is proposed. The method uses the fundamental vector transformation in which an estimated color of illumination is rotated to the white color of natural daylight. Then the transformed red, green, and blue values of each pixel are nonlinearly mapped into the 8-bit values to enhance intensity and saturation in the dark portion of the image. The proposed algorithm can produce the enhanced color image fast and efficiently without any space conversion or noticeable distortion.

• Computers and Concrete
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• v.34 no.1
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• pp.79-91
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• 2024

In symmetric cryptography, a cryptographically secure Substitution-Box (S-Box) is a key component of a block cipher. S-Box adds a confusion layer in block ciphers that provide resistance against well-known attacks. The generation of a cryptographically secure S-Box depends upon its generation mechanism. In this paper, we propose a novel framework for the construction of cryptographically secure S-Boxes. This framework uses a combination of linear fractional transformation and permutation functions. S-Boxes security is analyzed against well-known security criteria that include nonlinearity, bijectiveness, strict avalanche and bits independence criteria, linear and differential approximation probability. The S-Boxes can be used in the encryption of any grayscale digital images. The encrypted images are analyzed against well-known image analysis criteria that include pixel changing rates, correlation, entropy, and average change of intensity. The analysis of the encrypted image shows that our image encryption scheme is secure.

• Proceedings of the Korean Society of Broadcast Engineers Conference
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• 1996.06a
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• pp.181-185
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• 1996

Color image is largely corrupted by various ambient illumination. However, human perceives always white color as white under any illumination because of a characteristic of human vision, called color constancy. In the conventional algorithm which applied the constancy effect, after the RGB color space is transformed to the IHS(Intensity, Hue, and Saturation) color space, then the hue is preserved and the intensity or the saturation is properly enhanced. Then the enhanced IHS color is reversely transformed to the RGB color space. In this process, the color distortion is included due to the color gamut error. But in the proposed algorithm, there is not transformation. In that, the RGB color is considered as 3 dimensional color vector and we assume that white color is the natural daylight. As the color vector of the illumination can be calculated as the average vector of R, G, and B image, we can achieve the constancy effect by simply rotating the illumination vector to the white color vector. The simulation results show the efficiency of the vector rotating process for color image enhancement.

• 한국공간정보시스템학회:학술대회논문집
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• 2005.05a
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• pp.459-462
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• 2005

위성화상 또는 항공사진을 이용하여 산화지를 탐지하고 정량화하기 위한 여러 가지 방법적인 시도가 있었다. 보다 정확한 산화지 탐지를 위해, 본 연구에서는 기존의 고해상도 범색화상과 중 저해상도 다중분광 화상의 융합(fusion)에 주로 이용되었던 IHS(Intensity, Hue, Saturation) 색채변환을 산화지 탐지와 정량화에 적용하였다. IHS 색채변환을 이용한 Hue 조합화상의 산화지 최대우도분류 결과는 Landsat-7 ETM+ 7:4:1 조합화상보다 놀은 사용자분류 정확도를 나타냈으며 색상(Hue)과 채도(Saturation)가 명도(Intensity)에 비해 ETM+ 화상의 분광특성을 잘 반영하였다.