DSpace Community:
https://dspace.ewha.ac.kr/handle/2015.oak/239931
2024-03-28T12:08:15Z
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Observation of image quality for HDR micro LED display
https://dspace.ewha.ac.kr/handle/2015.oak/267735
Title: Observation of image quality for HDR micro LED display
Ewha Authors: 박영경
Abstract: This paper compared a high-dynamic range (HDR) micro-light-emitting diode (Micro LED) display with an LCD (Liquid Crystal Display) with a relatively low luminance range to determine the relationship between HDR and its factors and the effect of quality factors on the final image quality evaluation. The experimental subjects were general consumers, who evaluated images displayed on a Micro LED 4 K (110 in.) and an LCD 8 K (85 in.). The image-quality characteristics of the Micro LED reinforced texture analysis of the surface and clear image quality especially for the microscopic image group. Vividness perceptions have shown to affect all items, indicating that the increase in vividness due to the color gamut extension of Micro LED has a significant impact on the analytical evaluation of the details of an image. This study revealed that HDR is an important factor for image contrast that is comparable to the high resolution of the 8 K display. Among the currently commercialized displays, the Micro LED has the widest HDR, and clear, high-quality images are expected using this new display. © 2023 Elsevier B.V.
2023-01-01T00:00:00Z
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Lightness prediction of mirror display by amending CIECAM02 to include specular reflection
https://dspace.ewha.ac.kr/handle/2015.oak/263895
Title: Lightness prediction of mirror display by amending CIECAM02 to include specular reflection
Ewha Authors: 박영경
Abstract: This paper investigates if the color appearance model accurately predicts the lightness of a display whose surface features specular reflection such as a mirror display. Eight observers participate in psychophysical experiments and the results are compared with model prediction value. It is found that the model overestimates the lightness under the average surround condition where there is an intense specular reflection on the display surface. Based on the measurement results, we figured out that the conventional measurement method cannot measure practical specular reflection value. Thus we propose a new measurement method and modify the background parameter to include the specular reflection value. The proposed CIECAM02 considering specular reflection improves the coefficient of variation (CV) value under average surround condition from 20.56 to 12.40 while maintaining CVs under dim and dark surround conditions. In conclusion, we found that people perceive the specular reflection image as a background. (C) 2020 Optical Society of America under the terms of the OSA Open Access Publishing Agreement
2020-01-01T00:00:00Z
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Determining the color appearance of Helmholtz-Kohlrausch effect for self-emissive displays
https://dspace.ewha.ac.kr/handle/2015.oak/262447
Title: Determining the color appearance of Helmholtz-Kohlrausch effect for self-emissive displays
Ewha Authors: 박영경
Abstract: The correlation between the measured luminance of a stimulus and its perceptual brightness, which varies with saturation and color, has been studied extensively. The increase in the colorfulness of the stimulus generates a Helmholtz-Kohlrausch (H-K) effect, which appears ‘bright’. This study aims to quantify the H-K effect of a highly saturated self-luminous display and to apply it to the CAM16 model. It also attempts to quantify the H-K effect by using the ratio of lightness and luminance values obtained from the modified CAM16 model. Future research objectives include the accurate prediction of color attributes to develop a model of high saturation displays in order to compare conventional displays. © 2022 The Author(s). Published by Informa UK Limited, trading as Taylor & Francis Group on behalf of the Korean Information Display Society.
2022-01-01T00:00:00Z
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Flicker-Free Fringe-Field Switching Liquid Crystal Display Operable at Extremely Low Frequencies for Power Saving
https://dspace.ewha.ac.kr/handle/2015.oak/259493
Title: Flicker-Free Fringe-Field Switching Liquid Crystal Display Operable at Extremely Low Frequencies for Power Saving
Ewha Authors: 박영경
Abstract: A fringe-field switching (FFS) liquid crystal (LC) mode used with a negative dielectric LC (n-LC) that is operable at an extremely low-frequency signal voltage regime, without image flickering, is proposed. By doping charge-trapping fullerenes (doping concentration: 0.2 wt%) into a low-resistivity polyimide LC alignment layer of the FFS n-LC mode, the mobile ionic-charge density within the n-LC layer can be drastically decreased. Thus, excellent voltage-holding ratios of 98.24% and 87.91% are achievable in the proposed FFS n-LC mode at low operation frequencies of 0.5 Hz and 0.2 Hz, respectively, corresponding to the improvement rates of 155.69% and 1127.05% at each operation frequency, compared with the FFS n-LC mode without the fullerene doping case. The evaluation results by the modulation flicker level reveal that the operation frequency of the proposed device scheme can be decreased significantly (approximate to 0.2 Hz) without inducing the perceptible image-flickering problems.
2021-01-01T00:00:00Z