• Journal of the Optical Society of Korea
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• v.15 no.2
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• pp.140-145
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• 2011

Joint transform correlator (JTC) is a well known tool for color pattern recognition for a color image. Color images have red, green and blue components, thus in conventional JTC, three input channels of these color components are necessary for color pattern recognition. This paper proposes a new technique of color pattern recognition by decomposing the color image into three color components and recombining those components into a single gray image in the input plane. This new technique needs single input channel and single output CCD camera, thus a simple JTC can be used. We present various kinds of simulated results to show that our newly proposed technique can accurately recognize and discriminate color differences.

• 한국정보디스플레이학회:학술대회논문집
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• 2005.07a
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• pp.464-467
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• 2005

In this paper, we present techniques to manufacture color electronic ink for multi-color electrophoretic display implementation. The charged color pigments have been prepared to have superior affinity for dielectric fluid. White $TiO_2$ nanoparticles were modified with poly(methyl methacrylate) copolymer for a microencapsulated electrophoretic display system, in order to reduce the density mismatch between nanoparticles and dielectric medium. These color balls and white pigment particle suspensions were microencapsulated through the typical microencapsulation technique. We fabricate the microcapsules to the single layer on flexible ITO substrate to test the multi-color electrophoretic display application.

• 한국정보디스플레이학회:학술대회논문집
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• 2009.10a
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• pp.1469-1471
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• 2009

Effect of contamination of liquid crystal on the electrical behavior of liquid crystal display (LCD) by spilled components from color filter layer was investigated. It is noted that the level of contamination was different following the kind of liquid crystal and organic layers. Transmittance curve of LCD cell was shifted by spilled components of color filter and BM materials. C-V curve also showed different behavior following color filter type. The results obtained show the image sticking of LCD can be varied by pairing liquid crystal with color filter materials.

• The Journal of Korean Institute of Communications and Information Sciences
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• v.21 no.7
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• pp.1624-1632
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• 1996

Wavelet transform is widely used for high compression ratio image compression. It requeires a large memory when it is implemented by a hardware. Therefore, it is efficient to divide the entire image into blocks. Because the wavelet transform for divided blocks causes losses, pixels of the adjacent blocks are used. In the case of color image compression, the image is decomposed into brightness and color components, and then color components are downsampled. When the wavelet transform is performed by using pixels of adjacentblocks, the number of necessary pixels are doubled due to downsampling of color components. In this paper, we propose an efficient block wavelet transform using variablefilter length for brightness and color components. By using the proposed method, the number of pixels of adjacent blocks is optimized. We show the degradation of image quality due to the reduction of filter length for color components is negligible through simulations.

• Journal of the Semiconductor & Display Technology
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• v.13 no.4
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• pp.49-54
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• 2014

This paper proposes a new color segmentation method of vehicle license plates in the RGB color space. Firstly, the proposed method shifts the histogram of an input image rightwards and then stretches the image of the histogram slide. Secondly, the method separates each of the three RGB color components and performs the adaptive threshold processing with the three components, respectively. Finally, it combines the three components under the condition of making up a segment color and removes noises with the morphological processing. The proposed method is implemented using C language in an embedded Linux system for a high-speed real-time image processing. Experiments were conducted by using real vehicle images. The results show that the proposed algorithm is successful for most vehicle images. However, the method fails in some vehicles when the body and the license plate have the same color.

• Journal of Broadcast Engineering
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• v.20 no.5
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• pp.770-773
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• 2015

The contrast of the intensity components of color images usually needs to be improved in order to enhance the visual quality of color images. However, pure color regions can be saturated due to the excessive enhancement of that color. In this paper, a new method for enhancing the visual quality of color images using saturation components in the HSI color space is proposed, and the same enhancement technique in the YCbCr color space is proposed. Computer simulations show that the proposed method provides improved visual quality compared to the conventional methods.

• Journal of the Optical Society of Korea
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• v.19 no.6
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• pp.649-657
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• 2015

We present a surface color measurement including quantities of surface color, methods, and uncertainty evaluation. Based on a relation between spectral reflectance and surface color, we study how an uncertainty of spectral reflectance propagates to surface color. In analyzing the uncertainty propagation, we divide the uncertainty into uncorrelated components, fully correlated components, and correlated components with spectrally varying correlations. As an experimental example, we perform spectro-reflectometric measurements for ceramic color plates. With measured spectral reflectance and its uncertainty evaluation, we determine surface color and analyze uncertainties of the ceramic color plates.

• Proceedings of the Korean Society of Broadcast Engineers Conference
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• 2009.01a
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• pp.520-524
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• 2009

In compressed color images, colors are usually represented by luminance and chrominance (YCbCr) components. Considering characteristics of human vision system, chrominance (CbCr) components are generally represented more coarsely than luminance component. Aiming at possible recovery of chrominance components, we propose a model-based chrominance estimation algorithm where color images are modeled by a Markov random field (MRF). A simple MRF model is here used whose local conditional probability density function (pdf) for a color vector of a pixel is a Gaussian pdf depending on color vectors of its neighboring pixels. Chrominance components of a pixel are estimated by maximizing the conditional pdf given its luminance component and its neighboring color vectors. Experimental results show that the proposed chrominance estimation algorithm is effective for quality improvement of compressed color images such as JPEG and JPEG2000.

• Journal of the Optical Society of Korea
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• v.15 no.4
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• pp.335-339
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• 2011

Recently, we reported a single input channel joint transform correlator for the color pattern recognition which decomposes the input color image into three R, G, and B gray components and adds those components into a single gray image in the input plane. This technique has the merit of a single input channel instead of three input channels. However, we found this technique has some problems with discrimination impossibility in the case of a simple primary color pattern which results in the same gray level through the addition process. Thus, we propose a modified coding technique which selectively recombines the decomposed three R, G, and B gray components instead of the simple adding process. Simulated results show that the modified coding technique can accurately discriminate a variety of kinds of color images.

• 한국정보디스플레이학회:학술대회논문집
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• 2006.08a
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• pp.1587-1590
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• 2006

Through the engineering of recombination region and energy transfer in organic light emitting device, blue and red light emitting device with good color stability has been successfully obtained. A Color control layer (CCL), which emits green light through the energy transfer from the emission layers, has been introduced into the blue and red light emitting device for RGB white OLED. The RGB white OLED showed the current efficiency of 13 cd/A and the CIE coordinates of (0.33, 0.38) at $1000\;cd/m^2$. The device exhibited very stable spectrum with respect to operating current density and the CIE coordinates varied from (0.34, 0.38) to (0.31, 0.37) for $100-22000\;cd/m^2$.