• Journal of Korea Multimedia Society
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• v.9 no.4
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• pp.451-459
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• 2006

Color reproduction of small LCD display is quite different from that of standard CRT due to the difference of physical, electrical, and optical characteristics. In this paper, we propose a simple and practical method using gamma and CCT correction for improvement of color reproduction on a small LCD display. First, we investigate characteristics of a small LCD display such as brightness, uniformity, color temperature, white and black balance, and nonlinear gamma. And, we also analyze color reproduction region and CCT trajectory according to LCD's input levels. Finally, the optimum gamma and CCT compensation method using LUT is proposed, and our proposed method was realized at mobile phone without hardware modification. In the experimental results, the result image of proposed algorithm is more close to standard color.

• Journal of KIISE:Software and Applications
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• v.36 no.12
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• pp.986-995
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• 2009

Color affects people in their various combinations of hue, saturation and value. On the other hand, people may feel different emotion from the same color. If we can introduce these characteristics of color and people's emotion about color to emotion-based digital technologies and their contents, we can effectively draw users' interest and immersion to the contents. In this paper, we will show how people feel about color and present a method of image coloring that reflects the user's preference. First, we define basic templates that reflect the relationship between color and emotion, and then perform an image coloring. To reflect user's preference, we compute weights for hue, saturation and value through the experiments on each subject's preference about hue, saturation and value. The image coloring for each subject's taste will be drawn by updating the weights of hue, saturation and value. Through the results of experiments and surveys, we found that people were more satisfied with the transformation of the templates which reflected user's preference than the one that did not.

• Journal of Broadcast Engineering
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• v.15 no.2
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• pp.290-303
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• 2010

Recently, researches to improve a quality and a color of a display are being actively studied because of the prosperous growth of the flat panel displays such as LCD, PDP and OLED. Automatically adjusting color temperatures based on user preferences is the one of the researches to provide the optimum display color. In this paper, along with defining the problems of prior methods, the user preferences against the priori defined ranges proposed by the MPEG-7 color temperature descriptor are inspected. Based on the analysis of user preferences, an optimal color temperature conversion curve is proposed. As a result of an analysis by ANOVA, tendencies of the user preferences against each range are proven to be similar to the prior research results. The repetition of the color temperature conversion against an image is not statistically significant.

• The KIPS Transactions:PartB
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• v.18B no.2
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• pp.51-56
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• 2011

Algorithms for intrinsic images reduce color differences in RGB images caused by the temperature of black-body radiators. Based on the reference light and detecting single invariant direction, these algorithms are weak in real images which can have multiple invariant directions when the scene illuminant is a colored illuminant. To solve these problems, this paper proposes a method of acquiring an intrinsic image by omnidirectional projection of an ROI and a translation of white patch in the ${\chi}$-chromaticity space. Because it is not easy to analyze an image in the three-dimensional RGB space, the ${\chi}$-chromaticity is also employed without the brightness factor in this paper. After the effect of the colored illuminant is decreased by a translation of white patch, an invariant direction is detected by omnidirectional projection of an ROI in this chromaticity space. In case the RGB image has multiple invariant directions, only one ROI is selected with the bin, which has the highest frequency in 3D histogram. And then the two operations, projection and inverse transformation, make intrinsic image acquired. In the experiments, test images were four datasets presented by Ebner and evaluation methods was the follows: standard deviation of the invariant direction, the constancy measure, the color space measure and the color constancy measure. The experimental results showed that the proposed method had lower standard deviation than the entropy, that its performance was two times higher than the compared algorithm.

• Journal of Korea Multimedia Society
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• v.12 no.7
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• pp.1016-1021
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• 2009

Among many factors for evaluating the performance of color printers, the color uniformity is an important factor during the stage of development and mass production. Currently the color uniformity is measured manually using densitometers and the data is analyzed by inspectors to evaluate the performance. In this paper a new method of estimating the color uniformity using scanners and average brightness is presented. The color uniformity of printouts is estimated by using the test pattern and commercially available scanner. It is shown from experiments that the estimated data are similar to the data measured by densitometers. Also, with the analysis of the color uniformity, the usefulness of the proposed approach is presented.

• Journal of KIISE:Databases
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• v.34 no.4
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• pp.328-342
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• 2007

We propose a new cache conscious indexing structure for processing frequently updated data efficiently. Our proposed index structure is based on a KDB-Tree, one of the representative index structures based on space partitioning techniques. In this paper, we propose a data compression technique and a pointer elimination technique to increase the utilization of a cache line. To show our proposed index structure's superiority, we compare our index structure with variants of the CR-tree(e.g. the FF CR-tree and the SE CR-tree) in a variety of environments. As a result, our experimental results show that the proposed index structure achieves about 85%, 97%, and 86% performance improvements over the existing index structures in terms of insertion, update and cache-utilization, respectively.

• The KIPS Transactions:PartB
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• v.13B no.3 s.106
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• pp.205-214
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• 2006

Texts in images have significant and detailed information about the scenes, and if we can automatically detect and recognize those texts in real-time, it can be used in various applications. In this paper, we propose a new text detection method that can find texts from the various camera-captured images and propose a text segmentation method from the detected text regions. The detection method proposes color variance as a detection feature in RGB color space, and the segmentation method suggests an improved K-means color clustering in RGB color space. We have tested the proposed methods using various kinds of document style and natural scene images captured by digital cameras and mobile-phone camera, and we also tested the method with a portion of ICDAR[1] contest images.

• Science of Emotion and Sensibility
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• v.4 no.2
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• pp.63-68
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• 2001

We purpose to evaluate the fatigue of the error correcting task on monitoring with color temperature 2700 K, 4000 K and 6500 K. Results of questionnaire on subjective feeling of visual fatigue, mental fatigue and concentration. Visual fatigue and mental fatigue level were the lowest, concentration level was the highest and working performance was the best at 2700 K. At 6500 K, mental fatigue level was the highest and concentration level is the lowest. At 4000 K, visual fatigue level was the highest and working performance shown the worst ratio of correcting answers. As results, color temperature 2700 K is the best condition of color temperature to perform the error correcting task on monitoring.

• Journal of the Institute of Electronics and Information Engineers
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• v.54 no.2
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• pp.85-91
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• 2017

Lenses have different refractive indices for different wavelengths of light. This is why different wavelengths of rays are focused at different positions in the focal plane. Images are blurred and noticeable colored edges appear around the objects, which is known as chromatic aberration (CA). In this paper, an algorithm for removing CA artifacts in color images is proposed. Based on the fact that the gradients of color channels are highly correlated, the differences of the gradients of the channels in edges are minimized. The cost function is designed by using the gradients of the channels. Experimental results show the good performance of the proposed algorithm in removing the CA artifacts.

• Journal of KIISE:Databases
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• v.30 no.5
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• pp.429-437
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• 2003

Over the last decades, improvements in CPU speed have greatly exceeded those in memory and disk speeds by orders of magnitude and this enabled the use of compression techniques to reduce the database size as well as the query cost. Although compression techniques are employed in various database researches, there is little work on compressing multi-dimensional index structures. In this paper, we propose an efficient compression method called the hybrid encoding method (HEM) that is tailored to multi-dimensional indexing structures. The HEM compression significantly reduces the query cost and the size of multi-dimensional index structures. Through mathematical analyses and extensive experiments, we show that the HEM compression outperforms an existing method in terms of the index size and the query cost.