Browsing by Author "Cheng, Yu-Kuo"

Now showing 1 - 14 of 14

A human visual model for color break-up artifact in design field-sequential color LCDs
(2007)
Chen, Sheng-Chang
;
Yan, Shu-Ping
;
Cheng, Yu-Kuo
;
Lin, Fang-Cheng
;
Wei, Ching-Ming
A model to evaluate the color break-up (CBU) of field-sequential color liquid crystal display (FSC-LCD) had been successfully established. In order to quantify the CBU, "Color Break-Up Angle (CBUA)" was proposed as the evaluation index. From the psychophysical experiments, the CBUA=0.26 degrees was reported as the averaged threshold value for indistinguished color break-up. Consequently, the minimum frame rate could be derived from the model to suppress CBU in the various FSC-LCDs.
A localized partition approach for high-dynamic-range display
(2007)
Lu, Yen-Hsing
;
Cheng, Yu-Kuo
;
Tien, Chung-Hao
;
光電工程學系
;
Department of Photonics
A mosaic-form backlight system for high-dynamic-range display was introduced. The backlight unit consisting of a side-emitting LED, a quadratic light guide, and a concentric prism sheet can form an isolated square super-Gaussian distribution over the local area of liquid crystal panel. By means of our approach, high-dynamic-range display system can reduce the time required for processing compensated image signal.
A visual model of color break-up for design field-sequential LCDs
(2007)
Yan, Shu-Ping
;
Cheng, Yu-Kuo
;
Lin, Fang-Cheng
;
Wei, Ching-Ming
;
Huang, Yi-Pai
A model to evaluate the color break-up (CBU) of field-sequential color liquid crystal display (FSC-LCD) had been successfully established. In order to quantify the CBU, "Color Break-Up Angle (CBUA)" was proposed as the evaluation index. Front the psychophysical experiments. the CBUA=0.22 degrees was reported ass the averaged threshold value for indistinguished color break-up. Consequently, the minimum frame rate could be derived from the model to suppress CBU in the various FSC-LCDs.
Color gamut enlargement and adjustment by using multi-color LEDs in time sequential
(2005)
Cheng, Yu-Kuo
;
Shieh, Han-Ping D.
;
光電工程學系
;
Department of Photonics
Multi- color LEDs as primary colors, was studied to enlarge and/or adjust the color gamut of field-sequential full-color liquid crystal displays (FS-FC LCDs). Such an LCD is expected to extend the amount of perceivable colors, say much larger than 100% NTSC, for applications, especially, in reproduction of electronic photographs and TVs. Futhermore, the color temperature of LCDs can also be modulated by this configuration of light source.
Color Optimization Model for High Dynamic Range LCDs with RGB Color Backlights
(2009)
Chen, Yi-Ling
;
Cheng, Yu-Kuo
;
Huang, Yi-Pai
;
Shieh, Han-Ping D.
;
Yeh, Szu-Che
The high dynamic range liquid crystal display (TIDR-LCD) with the color controlled backlight can achieve low power consumption, high color saturation and high contrast ratio. A modified color model for the RGB LEDs backlight system was proposed to optimize the color appearance in this paper. By applying the model, the color accuracy of the HDR-image could be much improved with the clear image details.
Colorimetric Characterization of High Dynamic Range Liquid Crystal Displays and Its Application
(2009-01-01)
Cheng, Yu-Kuo
;
Shieh, Han-Ping D.
;
電信工程研究所
;
Institute of Communications Engineering
A modified colorimetric model was proposed to characterize the high dynamic range liquid crystal display (HDR LCD). Backlight intensity was incorporated to account for the display chromatic properties. Images, exemplifying regular and random backlight intensity distributions, were designed to evaluate the model. The results showed that chromaticity of three primaries was instable, and thus the device-dependent color transformation was inadequate in the HDR LCD. Moreover, the proposed model, in comparison with the model dedicated for the conventional LCD, was in average of less CIEDE2000 color difference values. Therefore, the proposed model was applicable for colorimetric color reproduction in the HDR LCD.
Colorimetric characterization of high-dynamic-range LCDs
(2008)
Cheng, Yu-Kuo
;
Shieh, Han-Ping D.
;
光電工程學系
;
Department of Photonics
A modified model, incorporating backlight intensity, for chromatic characterization of the HDR LCD was proposed. Images, exemplifying regular and random backlight distributions, were designed to evaluate the proposed model, The results showed that chromaticity of three primaries varied with incident backlight intensity. Moreover, CIEDE2000 color differences of the proposed model ranged from 0.02 to 2.35, while those of the conventional model were greater than 3.41.
Design and Evaluation of Light Spread Function for Area-Adaptive LCD System
(2009-01-01)
Cheng, Yu-Kuo
;
Lu, Yen-Hsing
;
Tien, Chung-Hao
;
Shieh, Han-Ping
;
光電工程學系
A methodology, based on two-dimensional super-Gaussian light spread functions (LSFs), was studied for the light-emitting-diode (LED) backlighting system in the high dynamic range (HDR) liquid crystal displays (LCDs). We proposed a novel LED-based optomechanical configuration to implement the desirable luminous pattern. A dual-liquid-crystal-panel system was constructed as a pseudo-HIE)R LCD to evaluate the super-Gaussian illumination. The proposed HDR scheme was verified via the current platform: overall luminance uniformity, contrast ratio and processing speed could be improved by factors of 1.55, 1.95-4.15, and 4.82, respectively. The design flexibility made the methodology applicable to any panel dimension and backlight division of the HDR LCDs, and to the conventional full-on backlighting LCDs as well.
Eco-Display - an LCD-TV Powered by a Battery?
(2009)
Shieh, Han-Ping D.
;
Huang, Yi-Pai
;
Lin, Fang-Chen
;
Chen, Huang-Ming P.
;
Cheng, Yu-Kuo
Color break-up (CBU) is a lethal issue of a high light efficiency field-sequential-color (FSC) LCD. Applying local color-backlight-dimming technology to FSC-LCDs, we demonstrated "Stencil-FSC" methods with afield rate as low as 120Hz to render a high luminance "multi-color" image on the first-field and effectively suppress CB U at the same time. In addition, the color filterless LCD with an intelligent LED backlight and even non polarized LC cell, optical thruput can increase by a factor of 10, yet with lower material cost/count for an Eco-Display.
High dynamic range display adopting high dynamic range imaging technique
(2006)
Cheng, Yu-Kuo
;
Wan, Yu-Wen
;
Shieh, Han-Ping D.
;
光電工程學系
;
Department of Photonics
Technique of high dynamic range imaging (HDRI) was introduced into conventional high dynamic range display (HDRD). Sharpness of image was further enhanced by improving local contrast ratio in the HDRI-based high dynamic range display.
Optical element apparatus for two-dimensional controllable localized partition backlight module
(2009-07-02)
Tien, Chung-Hao
;
Lu, Yen-Hsing
;
Cheng, Yu-Kuo
;
Lu, Po-Yi
The optical element apparatus for two-dimensional controllable localized partition backlight module is disclosed. The optical element apparatus comprises of a plurality of optical units which include a plurality of point light sources, light guides and collimating sheets. The point light source is located at the center of the light guide. The light guide includes the incident surface, the bottom place connecting with the light incident surface, and the light output surface. There are micro structures on the bottom place of the light guide and the top surface of the collimating sheet.
Super-Gaussian light spread function for high dynamic range displays
(2008)
Cheng, Yu-Kuo
;
Lu, Yen-Hsing
;
Lu, Po-I
;
Tien, Chung-Hao
;
Shieh, Han-Ping D.
Super-Gaussian light spread function was designed for high dynamic range liquid crystal displays. A dual-liquid-crystal-panel system was constructed to simulate an HDR display, and to evaluate the implementation of the proposed super Gaussian and a general Gaussian distributions. According to the results, luminance uniformity, and processing time of super-Gaussian LSF are superior to those of Gaussian LSF by factors of 1.55 and 178, respectively. Contrast ratio is improved by a factor about 2 to 4.15 as well. In addition, the undesired artifact, grid lines, can be suppressed to be invisible.
Two-Color-Field Sequential Method for Color-Filter-Free MVA-LCDs
(2009)
Cheng, Yu-Kuo
;
Cheng, Yi-Ru
;
Huang, Yi-Pai
;
Shieh, Han-Ping D.
;
光電工程學系
A novel displaying method, two-color-field driving scheme, was proposed for field-sequential-color LCDs without color filters. The least number of fields alleviated the demand for fast response LC modes in sequential-type LCDs. The proposed method reproduced full color images with acceptable calorimetric reproduction accuracy, average Delta E(00ave) < 3. Furthermore, less chrominance difference between the two fields was beneficial to suppress color break-up.
Two-Field Scheme: Spatiotemporal Modulation for Field Sequential Color LCDs
(2009-10-01)
Cheng, Yu-Kuo
;
Huang, Yi-Pai
;
Cheng, Yi-Ru
;
Shieh, Han-Ping D.
;
光電工程學系
A novel displaying method, two-field driving scheme, was proposed for field sequential color LCDs without color filter. A spatially modulated color backlight provided multi-primary low-resolution optical stimuli, which were then compensated by an LC panel to display detailed colorful images. That is, the manipulation on three (or more) spatial and two temporal degrees of freedom was sufficient to convey full color information. The simulation results showed that the proposed method achieved acceptable color reproduction accuracy, average CIEDE2000 color difference (Delta E(00)) < 3. The least number of fields particularly alleviated the demand for fast-response LC modes in sequential-type LCDs. Furthermore, color break-up suppression was observed due to less chrominance difference between the two fields.