Browsing by Author "Lin, Fang-Cheng"

Now showing 1 - 20 of 41

A Color Break-Up Suppression Method, Stencil-FSC Method, for Field-Sequential-Color(FSC) LCDs with low Power Consumption
(2008)
Huang, Yi-Pai
;
Lin, Fang-Cheng
;
Wei, Ching-Ming
;
Shieh, Han-Ping D.
;
Tsai, Chi-Chung
Field sequential color liquid crystal display (FSC-LCDs) is a display without color filter, so it achieves several attractive advantages. However, it has a serious issue called color breakup (CBU), which degrades image quality and causes viewers uncomfortable. Consequently, the "Stencil-FSC" method, which utilized multi-color image in a single field, was proposed to suppress CBU. Moreover, optimizations of hardware parameters were done to get the optimal CBU suppression. Finally, the Stencil-FSC method was successfully demonstrated on a 32-inch FSC-LCD with effectively suppressed CBU, resulting contrast ratio of more than 5,500:1, and average power consumption of less than 45 Watt.
A field sequential color LCD base on color field arrangement for color breakup and flicker reduction
(2007)
Hsu, Ya-Ting
;
Lin, Fang-Cheng
;
Chen, Chun-Ho
;
Huang, Yi-Pai
;
Shieh, Han-Ping D.
Field sequential color liquid crystal displays (FSC-LCDs) have several original benefits, including higher light efficiency, definition, and color saturation than those of conventional LCDs. However, FSC-LCDs are well known that the color breakup (CBU) is the serious issue needed to be solved. We have developed a new driving technique on a 5.6-inch OCB mode FSC-LCD. This proposed 4-color field arrangement (4-CFA) method can effectively eliminate the CBU of FSC-LCDs.
A Field Sequential Color LCD Based on Color Fields Arrangement for Color Breakup and Flicker Reduction
(2009-01-01)
Chen, Chun-Ho
;
Lin, Fang-Cheng
;
Hsu, Ya-Ting
;
Huang, Yi-Pai
;
Shieh, Han-Ping D.
The field sequential color (FSC) mechanism can effectively generate multi-primary color fields in temporal sequence to form a full-color image. Color breakup (CBU), however, has appeared intrinsically in conventional FSC displays to degrade visual qualities. A novel CBU suppression method, color fields arrangement (CFA), was proposed to eliminate the artifacts for FSC liquid crystal displays (LCDs). The modified order of consecutive color fields results in superimposed color images on a retina without CBU. Additionally, the 4-CFA method with a field rate of 240 Hz was found to avoid the flicker phenomenon on static images. The proposed method was successfully implemented on a 5.6-in optically compensated bend (OCB) LC panel. Our results confirm that the visibility of CBU artifacts can be reduced as the evaluation of dynamic and static models.
A field-sequential-color display with a local-primary-desaturation backlight scheme
(2011-03-01)
Zhang, Yuning
;
Lin, Fang-Cheng
;
Langendijk, Erno H. A.
;
光電工程學系
;
顯示科技研究所
Field-sequential-color technology eliminates the need for color filters in liquid-crystal displays (LCDs) and results in significant power savings and higher resolution. But the LCD suffers from color breakup, which degrades image quality and limits practical applications. By controlling the backlight temporally and spatially, a so-called local-primary-desaturation (LPD) backlight scheme was developed and implemented in a 180-Hz optically compensated bend (OCB) mode LCD equipped with a backlight consisting of a matrix of light-emitting diodes (LEDs). It restores image quality by suppressing color breakup and saves power because it has no color filter and uses local dimming. A perceptual experiment was implemented for verification, and the results showed that a field-sequential-color display with a local-primary-desaturation backlight reduced the color breakup from very annoying to not annoying and even invisible.
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 Hybrid Spatial-Temporal Color Display With Local-Primary-Desaturation Backlight Scheme
(2011-12-01)
Zhang, Yuning
;
Langendijk, Erno H. A.
;
Hammer, Martin
;
Lin, Fang-Cheng
;
光電工程學系
Field-sequential-color mode has benefits on energy efficiency, because colors are made by flashing the backlight red, green, and blue and the color filters are not needed, leading to increased light transmission. However, field-sequential-color mode causes annoying color breakup. In previous studies, a spatio-temporal display has been proposed as a hybrid solution to balance the increase of light transmission and the suppression of color breakup. However, color breakup remains visible for critical image content. In this paper, a 120-Hz liquid crystal display with two-color filters mounted with a backlight consisting of a light emitting diode matrix is introduced. The backlight colors are locally desatured according to the local image content, so the color difference between fields is reduced, and the perceived color breakup is effectively suppressed. Various examples with different color filter and backlight settings are described and analyzed, aiming at different display-performance objectives.
A real-time liquid crystal signal compensation method for high dynamic range LCD
(2007)
Liao, Lin-Yao
;
Lin, Fang-Cheng
;
Huang, Yi-Pai
;
Shieh, Han-Ping D.
;
Yeh, Szu-Che
Blur-mask approach was developed to simulate the backlight distribution of locally-controlled dimming LED backlight with lower computational complexity which is less than 1% of conventional convolution method. The If blur-mask approach was demonstrated to perform high image, quality and high contrast ratio (similar to 20,000 : 1) on a 37" LCD-TV. Compared with convolution, blur-mask approach has much lower computational complexity and succesfully demonstrated for real-time application.
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.
Adaptive LC/BL feedback control in field sequential color LCD technique for color breakup minimization
(2008-09-01)
Huang, Yi-Pai
;
Chen, Ke-Horng
;
Chen, Chun-Ho
;
Lin, Fang-Cheng
;
Shieh, Han-Ping D.
A full-color image on field sequential color (FSC) displays is composed of color fields in temporal sequence. With the FSC mechanism, color filters of liquid crystal displays (LCDs) can be removed to heighten the light efficiency and lower the material cost. Color breakup (CBU), however, has appeared intrinsically to degrade visual qualities. A novel gray level determination of liquid crystal and backlight (LC/BL) was proposed to suppress the CBU artifact on FSC-LCDs. Based on the image content in each frame, a dominated color-mixed field was found to minimize the color difference between the CBU and original image. Additionally, the feedback algorithm for the adaptive LC/BL signals was developed and implemented on a 32-inch optically compensated bend (OCB) mode LC panel. According to the evaluation of experiments and observations, the proposed method has been demonstrated to greatly suppress CBU in LCD applications.
Advanced Technologies for High Quality LC Display
(2008)
Huang, Yi-Pai
;
Lin, Fang-Cheng
;
Liao, Cheng-Yumr
;
Hsu, Ya-Ting
;
Huang, Wei-Kai
For achieving high quality LC displays, Advanced-MVA mode was proposed to wide the viewing angle, 4-color filed sequential method was utilized to increase the optical efficiency, and the local controlled LED backlight was applied to much improve the contrast and lower the power consumption.
Ambient-light-adaptive image quality enhancement for full-color e-paper displays using a saturation-based tone-mapping method
(2018-03-01)
Qin, Zong
;
Chen, Yi-Wen
;
Lin, Fang-Cheng
;
Hung, Chi-Mao
;
Shieh, Han-Ping David
Full-color e-paper displays that have a small color gamut encounter image tone distortions and contour artifacts in high-saturation regions. To solve these issues, in this paper, we comprehensively measure the colorimetric responses of input image signals and demonstrate that the perceptual colorfulness in terms of chroma abnormally declines when the input saturation is beyond a certain value. Accordingly, saturation-based tone-mapping curves are developed to map the abnormal high saturation to the range that the display is able to normally render. By testing several test charts and natural images, the recoveries of the original image tones and the removals of the contour artifacts are experimentally verified. More important, by discussing how to conduct a database of tone-mapping curves for different ambient lights and utilize the database for an unknown ambient light, the proposed method is proven to be completely ambient light adaptive.
Application of Field Emission as Backlight Unit for Liquid Crystal Displays
(2012-08-01)
Zhang, Yuning
;
Langendijk, Erno H. A.
;
Di, Yunsong
;
Lin, Fang-Cheng
;
光電工程學系
The paper first analyzes the effect of backlight unit for liquid crystal displays on the respect of image quality and power consumption. A spatially and temporally addressable backlight is required in the future liquid crystal displays which have lower power consumption and higher image quality. Compared to the currently used light emitting diode backlight, the simulation results indicate that a rectangular-shaped backlight has better performances on the respect of reducing power consumption and improving image quality. A backlight cell based on the field emission is manufactured and studied. It uses a mixture of multi-wall carbon nanotubes and tetrapod-like zinc oxide nanostructures as the cathode and applies spin-coating process for fabrication. The experiment shows that such field emission backlight unit has a low turn-on field which enables a high backlight luminance at acceptable driving voltage. Besides, this mixture cathode helps to improve the uniformity of field emission in both spatial and temporal domain which is important for the application of backlight unit.
Augmenting VR/AR Applications with EEG/EOG Monitoring and Oculo-Vestibular Recoupling
(2016-01-01)
Zao, John K.
;
Jung, Tzyy-Ping
;
Chang, Hung-Ming
;
Gan, Tchin-Tze
;
Wang, Yu-Te
Head-mounted virtual reality and augmented reality displays (a. k. a. VR/AR goggles) created a revolutionary multimedia genre that is seeking ever-broadening applications and novel natural human interfaces. Adding neuromonitoring and neurofeedback to this genre is expected to introduce a new dimension to user interaction with the cyber-world. This study presents the development of a Neuromonitoring VR/AR Goggle armed with electroencephalo- gram and electrooculogram sensors, programmable milli-Ampere current stimulators and wireless fog/cloud computing support. Beside of its potential use in mitigating cybersickness, this device may have potential applications in augmented cognition ranging from feedback-controlled perceptual training to on-line learning and virtual social interactions. A prototype of the device has been made from a Samsung Gear VR for S6. This study explains its technical design to ensure precision data sampling, synchronous event marking, real-time signal processing and big data cloud computing support. This study also demonstrates the effective-ness in measuring the event-related potentials during a visual oddball experiment.
Color Breakup Reduction by 180 Hz Stencil-FSC Method in Large-Sized Color Filter-Less LCDs
(2010-03-01)
Lin, Fang-Cheng
;
Huang, Yi-Pai
;
Shieh, Han-Ping David
;
光電工程學系
;
顯示科技研究所
Field-sequential color (FSC) is a high optical throughput technique for future green liquid crystal displays (LCDs). However, the FSC-LCD faces a lethal issue, color breakup (CBU) which degrades image clarity and prevents high level LCD-TV productions. We proposed the "180 Hz Stencil Field-Sequential-Color" method to redistribute intensities of the three primary color field-images to suppress CBU. By applying local color-backlight-dimming technology to FSC-LCDs, a low resolution colorful backlight panel combined with a high resolution color filter-less LC panel generated a "green-based multi-color" field-image which showed the most image luminance in the first field. Therefore, residual red and blue field-image intensities were reduced and effectively suppressed CBU when compared to field-rate increasing methods. In addition, to further implement hardware, the number of backlight divisions of 32 24 and a proper Gaussian point spread function profile were optimized via simulations while considering CBU reduction and image fidelity. Using optimized hardware parameters, the CBU phenomenon was suppressed by 50% of traditional RGB driving in simulation and was demonstrated on a 120 Hz 46-inch MVA LCD-TV.
Color Breakup Reduction by 180 Hz Stencil-FSC Method in Large-Sized Color Filter-Less LCDs (vol 6, pg 107, 2010)
(2010-06-01)
Lin, Fang-Cheng
;
Huang, Yi-Pai
;
Shieh, Han-Ping David
;
光電工程學系
;
顯示科技研究所
Color Breakup Reduction by 180Hz Stencil-FSC Method In Large-Sized Color Filter-Less LCD-TVs
(2009)
Lin, Fang-Cheng
;
Huang, Yi-Pai
;
Tsai, Chi-Chu
;
Shieh, Han-Ping D.
;
光電工程學系
We proposed the "180Hz Stencil-FSC" method to suppress color break-up (CBU) infield-sequential-color (FSC) LCDs. Applying local color-backlight-dimming technology to FSC- LCDs, a "green-based multi-color" field-image was generated to show most image luminance at the first field and effectively suppressed CBU even compared to field-rate increasing methods. In addition, for farther hardware implementation, the number of backlight divisions of 32x24 was optimized while considering CBU suppression and image fidelity.
Color breakup suppression based on global dimming for field sequential color displays using edge information in images
(2019-02-04)
Lin, Fang-Cheng
;
Qin, Zong
;
Teng, Kai-Tung
;
Huang, Yi-Pai
;
光電工程學系
Considering the high complexity of local dimming backlight that is necessary to effectively suppress color breakups for field sequential color liquid crystal displays (FSC-LCDs), a global dimming-based solution is proposed. This solution involves considering that the color breakups mainly occur at object edges of an image. By introducing an algorithm to present the edge information in a single field, evaluating color breakup performances, and experimentally verifying based on a 240-Hz LCD, lighter color breakups are revealed compared with mainstream local dimming-based solutions. Therefore, the proposed solution can achieve FSC-LCDs with better performance and practicality for advanced display applications. (C) 2019 Optical Society of America under the terms of the OSA Open Access Publishing Agreement
Color Filter-Less LCDs in Achieving High Contrast and Low Power Consumption by Stencil Field-Sequential-Color Method
(2010-03-01)
Lin, Fang-Cheng
;
Huang, Yi-Pai
;
Wei, Ching-Ming
;
Shieh, Han-Ping D.
;
光電工程學系
The field-sequential-color liquid crystal display (FSCLCD) without a color filter enables high light efficiency, wide color gamut, and low material cost. However, the visual defect of color breakup (CBU) is perceived when relative velocities exist between the screen image and the human eye. We proposed the Stencil-FSC method with a 240-Hz field rate to make CBU imperceptible. Given the Stencil-FSC method, the hardware parameters were optimized to reduce hardware complexity while maintaining sufficient suppression of CBU. After implementing Stencil-FSC on a 32-in FSCLCD, the image contrast ratio was shown to be ten times more than that of a conventional CCFL LCD, and the average power consumption was reduced to less than 35 W-a 67% savings in power consumption.
Color-breakup suppression and low-power consumption by using the Stencil-FSC method in field-sequential LCDs
(2009-03-01)
Lin, Fang-Cheng
;
Huang, Yi-Pai
;
Wei, Ching-Ming
;
Shieh, Han-Ping D.
;
光電工程學系
Field-sequential color (FSC) is a potential technique for low-power liquid-crystal displays (LCDs). However, it still experiences a serious visual artifact, color break-up (CBU), which degrades image quality. Consequently, the "Stencil Field-Sequential-Color (Stencil-FSC)" method, which applies local color-backlight-dimming technology at a 240-Hz field rate to FSC-LCDs, is proposed. Using the Stencil-FSC method not only suppressed CBU efficiently but also enhanced the image contrast ratio by using low average power consumption. After backlight signal optimization, the Stencil-FSC method was demonstrated on a 32-in. FSC-LCD and effectively suppressed the CBU, which resulted in more than a 27,000:1 dynamic contrast ratio and less than 40-W average power consumption.
Contrast-sensitivity-based evaluation method of a surveillance camera's visual resolution: improvement from the conventional slanted-edge spatial frequency response method
(2017-02-10)
Qin, Zong
;
Wong, Po-Jung
;
Chao, Wei-Chung
;
Lin, Fang-Cheng
;
Huang, Yi-Pai
Visual resolution is an important specification of a surveillance camera, and it is usually quantified by linewidths per picture height (LW/PH). The conventional evaluation method adopts the slanted-edge spatial frequency response (e-SFR) and uses a fixed decision contrast ratio to determine LW/PH. However, this method brings about a considerable error with respect to subjectively judged results because the perceptibility of the human vision system (HVS) varies with spatial frequency. Therefore, in this paper, a systematic calculation method, which combines the contrast sensitivity function characterizing the HVS and e-SFR, is proposed to solve LW/PH. Eight 720P camera modules in day mode, four 720P modules in night mode, and two 1080P modules in day mode are actually adopted. Corresponding to the three modes, mean absolute error between objective and subjective LW/PH are suppressed to as low as 26 (3.6% of 720P), 27 (3.8% of 720P), and 49 (4.5% of 1080P), while those of the conventional method are 68 (9.4% of 720P), 95 (13.2% of 720P), and 118 (10.9% of 1080P).(C) 2017 Optical Society of America