Global dimming method of liquid crystal display backlight based on image classification

Abstract

The invention relates to a global dimming method of liquid crystal display backlight based on image classification. The method includes the following steps: 1, determining how many types of images and classification thresholds, 2, computing brightness average value and contrast of all pixels of the input image, 3, classifying the images according to the classification thresholds, the brightness average value and the contrast, 4, determining parameter k in a backlight brightness computational formula according to the image category and computing a backlight dimming factor, 5, determining parameter a in a S-shaped curvilinear equation according to the image category, 6, computing brightness of an inflectional point on the S-shaped curve and obtaining corrected brightness of the inflectional point, 7, generating a S-shaped curve, 8, generating a light-emitting diode (LED) pulse width modulation signal according to the backlight dimming factor and changing the luminance of the LED light source plate completely, 9, adjusting brightness of each pixel according to the S-shaped curve so that the liquid crystal display displays the adjusted image according to the S-shaped curve. According to the global dimming method, computing parameter is selected according to the input image, and therefore, optimum effects of high contrast and low consumption of all images by means of dimming algorithm are guaranteed.

Description

technical field [0001] The invention belongs to the technical field of liquid crystal display, and in particular relates to backlight dynamic dimming technology. Background technique [0002] Liquid crystal displays have two inherent disadvantages: (1) low contrast; (2) high power consumption. At present, many researchers use backlight dynamic dimming technology to improve the contrast of liquid crystal display and reduce energy consumption at the same time. According to the backlight brightness adjustment method, the dynamic dimming technology can be divided into global dimming and local dimming. Global dimming is to change the brightness of the backlight as a whole, and local dimming is to divide the backlight into several areas that can be individually controlled, and determine the backlight brightness of this area according to the characteristic value of the image corresponding to the area. Compared with regional dimming, global dimming does not require partition desig...

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Problems solved by technology

[0002] Liquid crystal display has two inherent disadvantages: (1) low contrast; (2) high power consumption

[0003] Among the existing dimming algorithms, including the invention patent "LED backlight overall dimming method and its device" proposed by Fuzhou University (application number: 200910309165.6), the invention patent "side light" proposed by Guangzhou Skyworth Flat Display Technology Co., Ltd. Type LED backlight dynamic partition control method” (application number: 201010510536.X), the invention patent authorized by Qingdao Hisense Electric Co., Ltd. The invention patent applied for "a method for overall dimming of backlight for improving the contrast of liquid crystal display" (authorization number: ZL201110246263.7), etc., all use fixed calculation parameters for all images, and do not select parameters according to different images As a result, the display system using dynamic dimming technology cannot have a good effect on all images, that is, for some images, the energy saving effect may be better, but there is a large loss of details. In order to preserve details, It is necessary to increase the brightness of the backlight, which reduces the energy saving effect and severely limits the application of dynamic dimming technology.

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