Block-Based Gradient Descent for Local Backlight Dimming and Flicker Reduction

Author

Burini, Nino ; Mantel, Claire ; Nadernejad, Ehsan ; Korhonen, Jari ; Forchhammer, Soren ; Pedersen, Jesper Melgaard

Author_Institution

Dept. of Photonics Eng., Tech. Univ. of Denmark, Lyngby, Denmark

Volume

10

Issue

1

fYear

2014

fDate

Jan. 2014

Firstpage

71

Lastpage

79

Abstract

Local backlight dimming technology is a two-fold improvement for LED backlit LCD screens that allows to reduce power consumption and increase visual quality. This paper presents a fast version of an iterative backlight dimming algorithm based on gradient descent search. The speed is increased by exploiting the local uniformity of backlight to reduce the complexity for determining the optimal backlight of a given image. The algorithm is adapted to video sequences by using the backlight of the previous frame as a starting point to calculate the backlight for the current frame. Fast variations of backlight dimming over time can produce a visually annoying flicker artifact. To avoid this artifact, a control mechanism is also proposed.

Keywords

gradient methods; image sequences; light emitting diodes; liquid crystal displays; LED backlit LCD screens; block-based gradient descent; flicker reduction; iterative backlight dimming algorithm; liquid crystal display; local backlight dimming technology; power consumption; video sequences; visual quality; Cost function; Image color analysis; Image segmentation; Light emitting diodes; Measurement; Power demand; Video sequences; Backlight dimming; LED backlight; flicker; image quality; light leakage; liquid crystal display (LCD); optimization; power saving; video;

fLanguage

English

Journal_Title

Display Technology, Journal of

Publisher

ieee

ISSN

1551-319X

Type

jour

DOI

10.1109/JDT.2013.2286213

Filename

6637005