Browsing by Author "Chen, Chun-Ho"

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3D Air-Touch User Interface With High Touch Accuracy on Stereoscopic Displays
(2016-05)
Ting, Chih-Hung
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Jen, Tai-Hsiang
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Chen, Chun-Ho
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Shieh, Han-Ping D.
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Huang, Yi-Pai
To interact with stereoscopic images through 3D air-touch technology, the depth information for a touched 3D virtual object and the fingertip position should be aligned accurately. However, the fused 3D position is affected when the virtual object is blocked by the fingertip. Additionally, the 3D image with a large disparity decreases 3D touch accuracy. In order to improve the touch accuracy, virtual references and 3D image feedback were introduced respectively, and the touch accuracy was more than 90% based on a human interaction experiment.
3D interactive system based on vision computing of direct-flective cameras
(2016-08)
Li, Xuan
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Chen, Chun-Ho
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Huang, Yi-Pai
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光電工程學系
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Department of Photonics
A bare-finger 3D interactive technology for portable devices was developed. Using directive-flective cameras to reform the field of viewing, a blind working range close to the camera is eliminated. Moreover, the algorithm of vision computing, different from skin color detection, is presented to determine the positions of fingertips. The interactive range is workable from 1.5 to 50 cm above the entire surface of the display. The mean position error of less than 1 cm is achieved. This accuracy realizes a camera-based 3D interactive system allowing for near-distance functionality. Therefore, floating 3D images can be touched and interacted with, potentially creating more application and intuitive user-machine interface.
3D Interactive System Using Integral Photography by Embedded Optical Sensors for Portable Devices
(2016-11)
Chen, Chun-Ho
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Ting, Chih-Hung
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Huang, Yi-Pai
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光電工程學系
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顯示科技研究所
An air-touch interactive system for portable devices is presented. An embedded optical sensor based on this approach was developed to realize a lightweight and thin-form-factor three-dimensional (3-D) interactive system. Using integral photography, the 3-D coordinates of an object are calculated. Moreover, the micro-lens array is implemented to improve the working range to 80 mm and achieve a position error of less than 5 mm. The spatial resolution in x-y and z domains is 1 and 5 mm, respectively. In addition, this system can also support a gesture vector sensing function in the far field up to 150 mm.
A field sequential color LCD base on color field arrangement for color breakup and flicker reduction
(2007)
Hsu, Ya-Ting
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Lin, Fang-Cheng
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Chen, Chun-Ho
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Huang, Yi-Pai
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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
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Lin, Fang-Cheng
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Hsu, Ya-Ting
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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 novel 3D double screens display
(2006)
Lai, Chun-Hung
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Chen, Chun-Ho
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Shieh, Han-Ping D.
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光電工程學系
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Department of Photonics
A novel 3D double screens display system including a planar mirror and a micro-optical structure is proposed to yield dual full-sized 3D images. The lenticular-lenses-based micro-optical structure can generate 3D function and double screens function by rotating color filter's pixel layout with respect to the lenticular-lenses' positioning direction. Viewers can enjoy two image screens simultaneously with a planar mirror aligned. The proposed system has high potential on transforming the ordinary flat panel displays to 3D double screens displays.
A toroidal-lens designed structure for static type table-top floating image system with horizontal parallax function
(2017-07-01)
Chou, Ping-Yen
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Wu, Jui-Yi
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Hsieh, Po-Yuan
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Chen, Chun-Ho
;
Yu, Zih-Sin
A new structure of horizontal parallax table-top floating image system with toroidal-lens optical film was developed. In this design, the circular arranged pico-projectors limit the angular resolution of this system and display the floating image for surrounding viewing zones. In addition, the pinhole array and toroidal-lens layer compose the optical film in the system and correspond with each other; both of them could be considered as a repeatable unit to control the spatial resolution of image. After passing through the optical film, the direction, position, shape, and divergence angle of light field could be controlled as fan ray, which has a widely scattered angle in latitude and high directivity in longitude direction. Moreover, to confirm the optical properties, the proposed structure was built in the commercially optical software, LightTools v8.3, which is widely used in the simulation of light distribution. Based on the imaging principle and the inverse light tracking method, displaying floating image with circular viewing zones would be achieved.
Adaptive LC/BL feedback control in field sequential color LCD technique for color breakup minimization
(2008-09-01)
Huang, Yi-Pai
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Chen, Ke-Horng
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Chen, Chun-Ho
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Lin, Fang-Cheng
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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
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Lin, Fang-Cheng
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Liao, Cheng-Yumr
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Hsu, Ya-Ting
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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.
AMOLED panel driven by time-multiplexed clamped inverter circuit to reduce complex control signals
(2008-07-01)
Chen, Chun-Ho
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Chen, Ke-Horng
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Chen, Che-Chin
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Chen, Yi-Fu
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Shieh, Han-Ping D.
A time-multiplexing technique employing a pulse-width-modulation (PWM) charge-pump scheme for driving active-matrix organic light-emitting-diodes (AMOLEDs) is described. This scheme greatly reduces the number of control lines. The two-or four-phase PWM driving technique not only reduces costs through the simplification of manufacture but also improves the uniformity and lifetime of OLED panels. Experimental results show that the proposed circuit effectively and precisely controls the timing of OLED data-writing and light emission.
Digital halftoning method with simultaneously optimized perceptual image quality and drive current for multi-tonal electrophoretic displays
(2020-01-01)
Qin, Zong
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Wang, Hsin-, I
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Chen, Zi-Yu
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Chen, Chun-Ho
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Tien, Pei-Lin
While using digital halftoning to achieve multi-tones in al bit electrophoretic display (EPD), e.g., a three-pigment chromatic EPD, the drive current is significantly increased because of frequently reversed pixel values. Aimed at this issue, this study first establishes a model that can accurately predict the drive current from image content. Next, based on the direct binary search method, a new halftoning method is proposed by constructing a combined merit function that incorporates both the perceptual image quality and the drive current. As a result, in experiments using a 13.5 in. three-pigment EPD and several test images, compared with the well-developed error-diffusion method, the proposed method produces little image quality degradation, whereas the drive current increase with respect to the minimum current of the EPD is reduced from 71.8 to 33.0 mA, for a significant reduction of 54.0%. (C) 2019 Optical Society of America
Drive and control circuitry of CS filed-sequential color LCD with high data rate
(2007)
Hsu, Ya-Ting
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Lin, Fang-Cheng
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Chen, Chun-Ho
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Huang, Yi-Pai
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Shieh, Han-Ping D.
This paper provides a data controlling method for optically compensated, bend (OCB) field sequential color (FSC) liquid crystal displays (LCD). By using of the modem Electronic Design Automation (EDA) methods and new programmable logic devices FPGA, we construct the system circuitry architecture for further miniaturization or integration. Base on Xilinx Company's FPGA, the design was synthesized and simulated. The implementation was successfully test on a Xilinx XC3S400 for a 5.6-inch LCD.
Gray level redistribution in field sequential color LCD technique for color breakup reduction
(2008)
Chen, Chun-Ho
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Chen, Ke-Horng
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Huang, Yi-Pai
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Shieh, Han-Ping D.
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Ho, Ming-Tsung
A gray level redistribution for color filterless liquid crystal displays (LCDs) was proposed to suppress the color breakup (CBU) artifact on field sequential color (FSC) displays. This method discolors the primary color fields and redistributes the color intensities to a color-mixed field. The algorithm based on the image content was developed and implemented on a 32-inch panel. According to the evaluation of experiments and observations, the proposed method has been demonstrated to greatly suppress CBU in LCD applications.
High uniformity of large size backlight system with inclined LED array
(2005)
Chen, Chun-Ho
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Shieh, Han-Ping D.
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光電工程學系
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Department of Photonics
A large size backlight system which consists of a flat bottom reflector and an inclined LED array was developed. Tilted LEDs allow the angular distribution of source optimized without re-designing optical configuration. The novel backlight system with the optimum tilted angle of 10 degrees of LEDs, simpler in structure than the traditional ones, can yield the competitive uniformity of 85% and a color gamut of a factor of 1.3 wider than those of commercial CCFL backlight.
Long working range light field microscope with fast scanning multifocal liquid crystal microlens array
(2018-04-16)
Hsieh, Po-Yuan
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Chou, Ping-Yen
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Lin, Hsiu-An
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Chu, Chao-Yu
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Huang, Cheng-Ting
The light field microscope has the potential of recording the all information of biological specimens in real time with a conventional light source. To further extend the depth of field to broaden its applications, in this paper, we proposed a multifocal high-resistance liquid crystal microlens array instead of the fixed microlens array. The developed multifocal liquid crystal microlens array can provide high quality point spread function in multiple focal lengths. By adjusting the focal length of the liquid crystal microlens array sequentially, the total working range of the light field microscope can be much extended. Furthermore, in our proposed system, the intermediate image was placed in the virtual image space of the microlens array, where the condition of the lenslets numerical aperture was considerably smaller. Consequently, a thin-cell-gap liquid crystal microlens array, with fast response time can be implemented for time-multiplexed scanning. (C) 2018 Optical Society of America under the terms of the OSA Open Access Publishing Agreement
Magnification Enhanced Multi-Aperture System with Distorted Lens Design
(2017-01-01)
Liu, Yueh-Sheng
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Lin, Wei-Ting
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Chen, Chun-Ho
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Huang, Yi-Pai
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光電工程學系
In recent years, some companies take a dual-camera system to improve the magnification ability and zoomed image's quality in multi-function imaging devices. The solution comprises two apertures to perform a large zooming range without any mechanism moving optical elements: one with a wide-angle lens for lower magnification and the other with a telephoto lens for higher magnification. Nevertheless, this dual-camera system still needs to interpolate the digital zoomed image between the lower and higher magnification images results in a discontinuous quality of zoomed image. We propose a distorted lens (DL) dual-camera system with varying focal length for higher magnification performance and smoother optical zoom. The proposed optical system has a greater pixel count per field angle at the center of sensor than at the periphery of sensor. Therefore, we sacrifice some resolution of the peripheral FOV to enhance the resolution of the center FOV for improving the capability of magnification. For instance, using a 20 MP sensor and displaying a Full HD zoomed image, the maximum magnification factor of 7.54 is achieved in our distorted lens system, but this factor of 3.12 in the distortionless lens system. In other words, we raise the capability of magnification up to 242%.
Multi-performance film (MPF) for highly efficient LCD backlights
(2008)
Hsieh, Jen-Chieh
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Huang, Yi-Pai
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Chen, Chun-Ho
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Lo, Yu-Chun
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Fang, Jen-Yu
A multi-performance film (MPF) which has concave-parabolic cylinder micro prism structures was proposed to improve light coupling efficiency and to reduce lamp-Mura defect. A MPF combined light diffusion and light collecting performance as a multiple functional film. By applying the MPF wider FWHM angle, higher light output coupling efficiency, and slighter lamp-Mura were demonstrated on a 32-inch direct-type backlight.
Multi-user 3D film on a time-multiplexed side-emission backlight system
(2016-10-01)
Ting, Chih-Hung
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Chang, Yu-Cheng
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Chen, Chun-Ho
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Huang, Yi-Pai
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Tsai, Han-Wen
The desirable features for a portable 3D display include displaying 2D and 3D images without resolution degradation for multiple users, a 2D/3D switchable functionality, and, in particular, a compact volume. To produce a portable 3D display with these desirable features, we propose here a multi-user 3D film combined with a side-emission backlight system that has a directional-sequential light distribution. According to the simulation and experimental results, the multi-user 3D film successfully uses an inverted trapezoid structure to separate the rays of each light source and increases the number of observers from one to three. Additionally, the specification of the inverted trapezoid structure can be determined via equations for different designated viewing positions of the side observer and for the ratio of light intensities for the central and side observers. (C) 2016 Optical Society of America
Spatial-temporal division in field sequential color technique for color filterless LCD
(2007)
Chen, Che-Chin
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Chen, Yi-Fu
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Liu, Ti-Ti
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Chen, Chun-Ho
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Ho, Ming-Tsung
For color filterless display, a novel spatial and temporal division (STD) field sequence color (FSC) display technique divides each frame into many temporary sub-frames for improving color breakup (CBU) and motion blur effects. Fast refresh frequencies enhance the image quality. Spatial and temporal division achieves low cost and power consumption.