Eui-Yeol Oh

P-193L: Late-News Poster: Optimized Local Dimming Solution in IPS-mode LCD Technology

High contrast ratio and low power consumption for LCDs with LED BLU can be obtained by backlight local dimming with pixel compensation while maintaining image brightness. This technique can greatly increase the contrast ratio of IPS-mode LCDs. The technique, however, suffers from the side effects called flicker, halo, clipping, and non-uniformity. The intensity of the side effects is proportional to the amount of the local dimming applied. This paper presents a noble local dimming algorithm which adaptively determines the amount of backlight dimming by characteristics of each block in each scene and feedback values to maximize contrast ratio and power consumption saving effect without noticeable side effects. The experimental results of the proposed algorithm are shown along with those of conventional algorithms.

A backlight simulator for an edge-type backlight unit in local dimming systems

A local dimming backlight system achieves both high contrast and low power consumption. The backlight unit (BLU) consists of small blocks. The merits of the local dimming backlight system depend on the size of the blocks. In this work we propose a novel backlight simulator to examine the effect of block_size for edge-type BLUs. The backlight simulator is based on a mathematical model, developed using Matlab 2008b. The development time and cost are reduced by using the proposed backlight simulator.

67.3: Low Power Liquid Crystal Displays Using an Image Integrity-based Backlight Dimming Algorithm

paper presents a new backlight dimming approach using dynamic gray-level error control in liquid crystal displays. The existing methods using the fixed rate of clipped pixels degrade the image quality seriously for some images even after image compensation. The proposed method dynamically chooses the maximum luminance based on image integrity considering image characteristics. Therefore, it preserves the image quality above any desired level, while reducing power consumption as much as possible.

Hybrid Super Resolution Based on Curve Subdivision Interpolation and Neighbor Embedding

Curve subdivision interpolation reconstructs edge well with low complexity, however it lacks of ability to recover texture components, instead. While, neighbor embedding is superior in texture reconstruction. Therefore, in this paper, a novel Super Resolution technique which combines curve subdivision interpolation and neighbor embedding is proposed. First, edge region and non-edge regions are classified. Then, for edge region, the curve subdivision algorithm is used to make two polynomials derived from discrete pixels and adaptive weights are adapted for gradients of 4 different sides to make smooth edge. For non edge region, neighbor-embedding method is used to conserve texture property in original image. Consequently results show that the proposed technique conserves sharp edges and details in texture better, simultaneously.

An OLED driving currents compensation method with a CCD camera

In this work, we propose a promising approach that compensates OLED driving currents for large-sized OLED displays. With a CCD camera, pixel-to-pixel brightness differences were determined, and applied to compensate OLED driving currents for the purpose of achieving high luminance uniformity. We also implemented the proposed method as a system comprising a FPGA-based timing controller (T-con) and softwares, and the proposed method shows improved luminance uniformity over 20% at the gray level of 32/256.

P‐260L: Late‐News Poster: Design of Multi‐Screen RGBW LCDs for Information Displays

A 2×2 module prototype is developed with four 15-inch RGBW LCDs. Transmittance of LCD is increased with the low resolution, that is, qXGA(512×RG×384×BW). Using a new RGBW conversion algorithm, white and R/G/B luminance are increased 270% and 130% respectively in comparison with the 15-inch conventional RGB LCD. An electronics system is implemented and a GUI is developed to support the hardware image control for tiled display.