• Journal of Broadcast Engineering
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• v.27 no.5
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• pp.808-811
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• 2022

Display under strong ambient lighting is perceived darker than it really is. Existing techniques for solving the problem in terms of software show limitations in that image enhancement techniques are applied regardless of ambient lighting or chrominance is not improved compared to luminance. Therefore, this paper proposes a visibility enhancement algorithm using deep learning to adaptively respond to ambient lighting values and an equation to restore optimal chrominance for luminance. The algorithm receives an ambient lighting value with the input image, and then applies a deep learning model and chrominance restoration equation to generate an image to minimize the difference between the degradation modeling of enhanced image and the input image. Qualitative evaluation proves that the algorithm shows excellent performance in improving visibility under strong ambient lighting through comparison of images applied with degradation modeling.

• Journal of the Korea Institute of Information and Communication Engineering
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• v.17 no.7
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• pp.1702-1708
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• 2013

OLED has good efficiency of power consumption by having no power consumption from black color as different with LCD. when it has white color, all RGB pixel should be glowing with high power consumption and that can make it has short life time. This paper suggest the way of low power consumption for OLED panel using adaptive luminance enhancement with color compensation and implement it as hardware. This way which is based on luminance information of input image makes converted luminance value from each pixel in real time. There is with using the basic idea of chromaticity reduction algorithm, showing new algorithm of color correction. And performance of proposed method was confirmed by comparing the conventional method in experiments about 48.43% current reduction. The proposed method was designed by Verilog HDL and was verified by using OpenCV and Windows Program.

• Journal of the Institute of Electronics and Information Engineers
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• v.53 no.6
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• pp.101-109
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• 2016

The images captured by digital still cameras or mobile phones are not always satisfactory because the devices have limited dynamic ranges compared with that of the real world. To cope with the problems, tone mapping function based methods and retinex theory based methods are studied. However, these methods generate a halo artifact or limited enhancement of global and local contrasts. The proposed method estimates illumination information used for image enhancement by optimizing a dynamic range of input image. The estimated illumination information has smoothness characteristic where the luminance is flat and does not have where the luminance changes to prevent the halo artifact. Additionally, the estimated illumination information and surrounding pixel values are considered when the tone mapping function is applied to overcome the limitations of the conventional tone mapping function approach. Experimental results show that the proposed algorithm outperforms the conventional methods on objective and subjective criteria.

• The Journal of the Korea Contents Association
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• v.5 no.3
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• pp.123-131
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• 2005

Among the digital halftoning, the error diffusion halftoning gives better subjective quality than other halftoning techniques. But it also makes edges of objects blurred. To overcome the defect, this paper proposes the modified error diffusion halftoning algorithm to enhance the edges using the spatial perceptual properties of the human visual system. Using the properties that the human eyes perceive not the pixel's luminance itself but the local average luminance and the information that human eyes perceive spatial variation, the proposed method computes information of edge enhancement(IEE). The IEE is added to the quantizer's input pixel and feeds into the halftoning quantizer. The quantizer produces the halftone image having the enhanced edge. Also this paper proposes the technique that the coefficients of the error diffusion filter are adapted according to the correlation among color components. The computer simulation results show that the proposed method produces finer halftoning images than conventional methods due to the enhanced edges. And the proposed method also preserves similar in edges to original image and reduces some defects such as color impulse and false contours.

• 한국정보디스플레이학회:학술대회논문집
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• 2007.08b
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• pp.1569-1572
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• 2007

A two-dimensional fluid simulation code has been developed in order to investigate discharge phenomena and to improve plasma luminous efficiency in a Hg flat fluorescent lamp (FFL) for an LCD backlight unit. In this study, the method of a two-dimensional fluid simulation for FFL is explained and the simulation results of Hg-Ar-Ne mixture gas are presented for the enhancement of the luminance efficiency. The effects of various parameters, such as driving voltage, frequency, and gas mixture ratio, are investigated. The luminance efficiency increased with increasing fraction of mercury but the increasing fraction of argon did not affect the efficiency much.

• Proceedings of the Korean Society of Broadcast Engineers Conference
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• 2009.01a
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• pp.23-27
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• 2009

A scalable video coding (SVC) extension to the H.264/AVC standard has been developed by the Joint Video Team (JVT). SVC provides spatial, temporal and quality scalability with high coding efficiency and low complexity. SVC is now developing the extension of the first version including color format scalability. The paper proposes to remove some luminance related header and luminance coefficients when an enhancement layer adds only additional color information to its lower layer. Experimental results shows 0.6 dB PSNR gain on average in coding efficiency compared with an approach using the existing SVC standard.

• Journal of Information Display
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• v.5 no.1
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• pp.7-15
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• 2004

A highly simplified backlight unit mainly composed of diffractive grating in sub-micron order imprinted light-guide plate (LGP) is proposed for edge-lit backlight unit. Optical characteristics of the imprinted LGP are examined by RCWA and the performance is verified through Monte Carlo simulation. Results show that the diffraction efficiency, luminous flux and its uniformity over the area are significantly affected by the angle of incident ray. Consequently couples of design considerations are additionally proposed to enhance luminous flux. In terms of peak luminance and out-coupling luminous flux, the experimental results are agreed well with the performance simulation. Finally, compared with optical characteristics of conventional backlight unit, we could conclude that the proposed simplified backlight unit made of diffractive grating imprinted light-guide plate is a good substitute for the conventional backlight unit.

• The KIPS Transactions:PartB
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• v.13B no.2 s.105
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• pp.77-82
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• 2006

Digital halftoning is the technique to obtain a bilevel-toned image from continuous-toned image. Among halftoning methods, the error diffusion method gives better subjective quality than other halftoning ones. But it also makes edges of objects blurred. To overcome the defect, we proposes the modified error diffusion to enhance the edges using the property that human vision perceives the local average luminance and doesn't perceive a little variation of the spatial variation. The proposed method computes a spatialactivity, which is the difference between a pixel luminance and the average of its $3{\times}3$ neighborhood pixels' Iuminance weighted according to the spatial positioning. The system also usesof edge enhancement (IEE), which is computed from the normalized spatial activitymultiplied by the average luminance. The IEE is added to the quantizer's input pixel and feeds into the halftoning quantizer. The quantizer produces the halftone image having the enhanced edge. The computer experimental results show that the proposed method produces clearer bilevel-toned images than conventional methodsand the edge of objects is preserved well. Also the performance of the preposed method is improved, compared with that of the conventional method by measuring the edge correlation and the local average accordance at some ranges of viewing distance.

• The Journal of Korean Institute of Communications and Information Sciences
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• v.38A no.11
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• pp.928-937
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• 2013

This paper presents a novel contrast enhancement method based on singular value decomposition and image pyramid. The proposed method consists mainly of four steps. The proposed algorithm firstly decomposes image into band-pass images, including basis image and detail images, to improve both the global contrast and the local detail. In the global contrast process, singular value decomposition is used for contrast enhancement; the local detail scheme uses weighting factors. In the final image composition process, the proposed algorithm combines color and luminance components in order to preserve the color consistency. Experimental results show that the proposed algorithm improves contrast performance and enhances detail compared to conventional methods.

• Journal of the Institute of Electronics and Information Engineers
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• v.53 no.9
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• pp.110-117
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• 2016

Applying the contrast enhancement algorithms to luminance values of color images is a widely used approach to enhance the contrast of color images. The results obtained by this approach have reduced saturation compared with that of the original images in spite of contrast enhancement without color degradation. Applying the contrast enhancement algorithm to each channel of color images is another approach for the contrast enhancement of color images. This method produces improved images in terms of contrast and saturation while the hue of original images is changed. In this paper, main cause of color degradation is analyzed and then solving the problem based on the analysis. The channel adaptive contrast enhancement method considering characteristics of each channel is also proposed to deal with color degradation. As a result, the proposed method enhances the contrast and saturation simultaneously without color degradation. Experimental results show that the proposed method outperforms the conventional methods not only on subjective evaluation but on objective criteria.