Chih-Chang Lai

Backlight power reduction and image contrast enhancement using adaptive dimming for global backlight applications

The paper presents an adaptive dimming technique to reduce backlight power consumption and enhance image contrast for global backlight applications. The proposed adaptive dimming technique consists of two new algorithms: backlight dimming algorithm and contrast enhancement algorithm. The backlight-dimming algorithm obtains appropriate 0% to 50% backlight power reduction depending on characteristics of the image data. The contrast enhancement algorithm not only reduces the adverse effect of backlight power saving, but also improves 20.75% enhancement of image contrast ratio on the average. Numerous simulation results are used for illustration of the effectiveness and merits of the proposed adaptive dimming technique. Experimental results are conducted to show the performance and usefulness of the proposed technique on a 2.2-inch mobile phone liquid crystal display (LCD) made by thin-film-transistor (TFT) technology.

A Modified Stripe-RGBW TFT-LCD with Image-Processing Engine for Mobile Phone Displays

This paper presents a modified stripe-RGBW (MS-RGBW) color filter structure to keep the same high resolution, and obtain a higher brightness in comparison with conventional RGB color filters. An image-processing engine is also designed to achieve sharp text image for thin-film-transistor (TFT) LCD with the MS-RGBW color filter. In MS-RGBW color filter structure, each pixel with three sub-pixels is the same area to that in the conventional RGB stripe color filter, and each row shifts two sub-pixels. The image-processing engine consists of two new algorithms: RGB-RGBW mapping algorithm and sub-pixel rendering algorithm. The RGB-RGBW mapping algorithm obtains a new RGBW image data without distortion in hue and saturation. The sub-pixel rendering algorithm transfers RGBW data into a MS-RGBW color filter structure in order to achieve sharp text image. Numerous simulation results are provided to illustrate the merits and performance of the proposed techniques. The usefulness of the proposed techniques for mobile phone displays is exemplified by conducting several experimental results on a 2.2-inch TFT LCD.

Neural calibration and Kalman filter position estimation for touch panels

This paper develops methodologies and techniques for calibration and dynamic touching position estimation of touch panels using adaptive linear neural networks (ALNN) and Kalman filter. A neural-based calibration method is proposed to determine nonlinear mapping relationships of measured and known touch points, thereby calibrating their positions in a real-time manner. In order to obtain position estimation of fast moving points in the drawing mode, a Kalman filtering scheme is proposed to achieve satisfactory precision. Numerous simulation results are provided to show the effectiveness and feasibility of the proposed ALNN method and the Kalman filter estimation algorithm. Experimental results are described which have been conducted to show that the proposed calibration and estimation approaches perform well for electronic consumer products, such as notebooks, personal digital assistants (PDAs) and etc.

51.4: Backlight Power Reduction and Image Contrast Enhancement Using Adaptive Dimming for Global Backlight Applications

The backlight-dimming algorithm obtains appropriate 0% to 50% backlight power reduction depending on characteristics of the image data. The contrast enhancement algorithm not only reduces the adverse effect of backlight power saving, but also improves averagely 20.75% enhancement of image contrast ratio.

Color Gamut and Contrast Enhancement for Mobile Phone Displays

For modern mobile phone displays, their driving integrated circuit (IC) solutions, often called total solutions, have included various functions, such as scanning, driving, power-level conversion, image storage memory, timing control, and standard interfacing; however, most of them lack of realtime image processing engine. In this paper, a novel real-time pixel-level image processing algorithm is presented to enlarge image color gamut and enhance image contrast without frame memory for mobile phone displays. This image processing algorithm simultaneously executes two parallel algorithms: rich color and contrast enhancement. The rich color algorithm obtains a wide color gamut image data showing more than 30% area enhancement in the CIE1931 color space without hue distortion. The contrast enhancement algorithm improves 20% contrast ratio improvement. Numerous simulation results are provided to illustrate the feasibility and efficacy of the proposed algorithms and image processing engine. Experimental results are conducted to show the performance and usefulness of the proposed composite algorithm for 2.2- inch mobile phone TFT LCDs.

Semi-autonomous control of a wheeled mobile service robot using a rate gyro and a CCD camera

This paper develops methodologies and techniques for semi-autonomous control of a wheeled service robot with a gyro rate and a CCD camera. A mechatronic design approach is used to construct a wheeled service robot vehicle that performs missions at any indoor flat environments. A remote manual control technique is developed using a joystick. Using a rate gyro and a CCD camera, four user-friendly semi-autonomous control operations are proposed to steer the vehicle easily and effectively. Several experiments results are conducted to illustrate the efficacy of the proposed methods.

Brightness improvement of color display systems using white sub-pixel structure and mapping algorithm

This paper develops methodology and technique for brightness improvement of color display systems using white sub-pixels. Based on human vision discrimination, three novel white sub-pixel filter structures without loss of original resolution are presented to enhance brightness of conventional stripe, delta and pentile color filter architectures. A new mapping algorithm fusing RGB sub-pixel data around a white sub-pixel is proposed to improve overall image quality. Numerous simulation results are provided to show the feasibility and efficacy of the proposed method for improving conventional stripe, delta and pentile display systems. An experimental result is described which has been conducted to show that the proposed color display system performs well for electronic consumer products, such as notebooks, personal digital assistants, and mobile phone, etc.

Brightness Improvement of Color LCD Systems Using White Sub-pixel Structure and Fuzzy Mapping Algorithm

This paper presents three novel color filter structures and a fuzzy mapping algorithm for improving brightness of color LCD systems. On the basis of human vision discrimination, the three color filter structures with white sub-pixels are presented to enhance brightness of conventional stripe, Delta and PenTile color filter architectures without loss of their original color saturation and resolution. A new fuzzy mapping algorithm using RGB sub-pixel data around white sub-pixels is proposed to obtain better image quality. Numerous simulation and experimental results are provided to show the efficacy of the proposed structures and mapping method. The proposed techniques can be expected to be pragmatic and effective in designing color LCD display systems for electronic consumer products, such as notebooks, personal digital assistants, mobile phones and etc.

Brightness Improvement of Color Display Systems Using White Sub-pixel Structure and Fuzzy Mapping Algorithm

This paper develops a fuzzy mapping methodology for brightness improvement of color display systems using white sub-pixels. Based on human vision discrimination, three novel white sub-pixel filter structures without loss of original resolution are presented to enhance brightness of conventional stripe, Delta and PenTile color filter architectures. A new mapping fuzzy algorithm using RGB sub-pixel data around a white subpixel is proposed to improve overall image quality. Numerous simulation results are provided to show the efficacy of the proposed method for improving conventional stripe, delta and PenTile display systems. Experimental results are described which has been conducted to show that the proposed color display system performs well for electronic consumer products, such as notebooks, personal digital assistants, and mobile phone, etc.

Error backpropagation neural calibration and Kalman filter position estimation for touch panels

This work develops a methodology and technique for calibration and dynamic touching position estimation of touch panels using error backpropagation neural networks (EBPNN) and Kalman filter. A neural-based calibration method is presented to determine the nonlinear mapping relationships of the measured and known touch points, and then calibrate their positions in a real-time manner. In order to obtain position estimation of fast moving points in the drawing mode, a Kalman filtering scheme is proposed to achieve a satisfactory precision.