KR20130063851A - Flat panel display and method for driving the same - Google Patents

Abstract

PURPOSE: A flat panel display device and a driving method thereof are provided to output an image with a desired contrast ratio and brightness of a user. CONSTITUTION: A display panel(2) displays images by defining a cross pixel of a number of gate lines and a number of data lines. A gate driver(4) drives a number of gate lines. A data driver(6) drives a number of data lines. A dynamic data stretching unit(10) generates histogram by analyzing inputted image data. The dynamic data stretching unit generates a transform function by comparing and analyzing a first function belonging to generated fuzzy with a second function belonging to fuzzy tuned according to the taste of a user or a first or a third base function, and stretches the inputted image data according to the transform function, and then outputs the stretched image data. A timing controller(8) controls the driving timing of the gate driver or the data driver, and aligns and supplies the stretched image data to the data driver according to the driving of the display panel.

Description

Flat panel display and its driving method {FLAT PANEL DISPLAY AND METHOD FOR DRIVING THE SAME}

The present invention relates to a flat panel display device and a method of driving the same, capable of expressing finer images by performing data stretching by analyzing input image data for each luminance region.

Recently, a data stretching method has been applied to increase the contrast ratio and the brightness of a flat panel display. The data stretching method analyzes input image data and stretches the image data according to the analyzed result to increase contrast ratio and brightness.

However, in the conventional data stretching method, since data stretching is performed after analyzing the entire screen, there is a problem that image quality compensation is not properly performed in a composite image in which a high luminance image and a low luminance image exist together.

SUMMARY OF THE INVENTION The present invention has been made in view of the above-described problems, and an object thereof is to provide a flat panel display device and a method of driving the same, which allow more detailed image representation by analyzing the input image data for each luminance region and stretching the data.

According to an aspect of the present invention, there is provided a flat panel display, including: a display panel configured to display an image by defining pixels at intersections of a plurality of gate lines and a plurality of data lines; A gate driver for driving the plurality of gate lines; A data driver driving the plurality of data lines; Analyze the input image data to generate a histogram, generate a fuzzy belonging first function based on the histogram, and tune the fuzzy belonging second function and the first to the first functions according to the user's preferences. A dynamic data stretching unit for generating a transform function by comparing and analyzing three basis functions and stretching and outputting the input image data according to the transform function; And a timing controller configured to control the cylinder timing of the gate driver and the data driver, and to supply the data driver to align the image data stretched by the stretcher according to the driving of the display panel.

The dynamic data stretching unit receives a histogram by receiving the image data on a frame-by-frame basis; Defining a luminance range by dividing the luminance range into a plurality of luminance regions, analyzing the histogram for each of the plurality of luminance regions, calculating a peak frequency value, and generating the fuzzy belonging first function based on the calculated peak frequency values. 1 function generator; An operation unit which calculates a degree of reflection of the fuzzy belonging first function according to the fuzzy belonging second function and obtains a weight for each luminance range according to a result of the calculation; A second function generator for generating a conversion function by combining the weights of the luminance ranges with the first to third basis functions; And a data stretching processor configured to stretch and output the image data by using the transform function.

The first function generator obtains a probability density function from the histogram by using a kernel density estimation method, calculates a maximum value, a local maximum value, and a local minimum value of the probability density function, and has a peak at the maximum value. And generating a first function of the fuzzy belonging in the form.

The fuzzy belonging second function may have a function value between 0 and 1 in which a reflection ratio of the fuzzy belonging first function is determined based on a tuning value of the user.

The first basis function is a function in which the slope increases as the luminance increases, and the second basis function is a function in which the slope increases in the region where the luminance is relatively low and the slope decreases in the region where the luminance is relatively high. The three basis functions are characterized in that the slope decreases as the luminance increases.

In addition, to achieve the above object, a driving method of a flat panel display device according to an embodiment of the present invention comprises the steps of generating a histogram of the input image data; Defining a luminance range by dividing the luminance range into a plurality of luminance regions, analyzing the histogram for each of the plurality of luminance regions, calculating a peak frequency value, and generating a fuzzy belonging first function based on the calculated peak frequency values; Generating a fuzzy belonging second function for determining a degree of reflection of the fuzzy belonging first function for each of the plurality of luminance regions; Comparing the fuzzy belonging first and second functions and obtaining a weight for each luminance range according to a result of the operation; Generating first to third basis functions; Generating a conversion function by combining the weights of the luminance ranges with the first to third basis functions; Stretching the image data using the transform function; And displaying the stretched image data on the display panel.

The generating of the fuzzy belonging first function may include obtaining a probability density function from the histogram by using kernel density estimation; And calculating a maximum value, a local maximum value, and a local minimum value of the probability density function to generate the fuzzy belonging first function in the form of a linear function having a point at the maximum value.

The generating of the fuzzy belonging second function may include: inputting a tuning value by a user to determine a reflection ratio of the fuzzy belonging first function; And generating the fuzzy belonging second function having a function value between 0 and 1 in which a reflection ratio of the fuzzy belonging first function is determined based on the tuning value of the user.

The first basis function is a function tuned by a user to correct an image having a relatively high luminance, the second basis function is a function tuned by a user to correct an image having a uniform luminance, and the third basis function. Is a function tuned by a user to correct a relatively low luminance image.

The first basis function is a function in which the slope increases as the luminance increases, and the second basis function is a function in which the slope increases in the region where the luminance is relatively low and the slope decreases in the region where the luminance is relatively high. The three basis functions are characterized in that the slope gradually decreases as the luminance increases.

According to the present invention, detailed image expression is possible by stretching data based on a result of analyzing input image data for each luminance region. In addition, since the user sets the fuzzy belonging second function and the first to third basis functions according to the preference, the user can output an image having a desired contrast ratio and luminance.

1 is a flowchart illustrating a method of driving a flat panel display device according to an exemplary embodiment of the present invention.
2 is a block diagram of a flat panel display device according to an exemplary embodiment.
3 is a block diagram of the dynamic data stretching unit 10 shown in FIG. 2.
4 is a diagram for describing an operation of the first function generator 14.
5 is a graph showing an example of the fuzzy belonging second function F2.
6 is a graph showing an example of the first to third basis functions FB1 to FB3.
FIG. 7 is a diagram for describing an operation of the second function generator 18.

Hereinafter, a flat panel display device and a driving method thereof according to an embodiment of the present invention will be described in detail with reference to the accompanying drawings.

1 is a flowchart illustrating a method of driving a flat panel display device according to an exemplary embodiment of the present invention.

The driving method illustrated in FIG. 1 includes generating a histogram of the input image data (S1); The luminance range is defined by dividing the luminance range into a plurality of luminance regions (for example, the first to third regions), the histogram is analyzed for each of the luminance regions, the peak frequency value is calculated, and based on the calculated peak frequency values, Generating a fuzzy belonging first function (S2); Generating a fuzzy belonging second function for determining a degree of reflection of the fuzzy belonging first function for each of a plurality of luminance regions (S3); Comparing and calculating first and second functions belonging to the fuzzy and obtaining weights for each luminance range according to a result of the operation (S4); Generating first to third basis functions (S5); Generating a transform function by combining the weights for each luminance range and the first to third basis functions (S6); Stretching the image data using the transform function (S7); And displaying the stretched image data on the display panel (S8).

As described above, according to the exemplary embodiment, more detailed image expression is possible by stretching the data based on the result of analyzing the input image data for each luminance region. In addition, since the user sets the fuzzy belonging second function and the first to third basis functions according to the preference, the user can output an image having a desired contrast ratio and luminance. Hereinafter, a flat panel display according to an exemplary embodiment will be described in detail.

2 is a block diagram of a flat panel display device according to an exemplary embodiment.

The flat panel display shown in FIG. 2 includes a display panel 2, a gate driver 4, a data driver 6, a timing controller 8, and a dynamic data stretcher.

The display panel 2 includes a plurality of data lines DL and gate lines GL that cross each other. The plurality of data lines DL and the plurality of gate lines GL define intersection subpixels. A thin film transistor is formed in each subpixel, and the thin film transistor supplies a data voltage provided from the data line DL to the subpixel in response to a scan signal provided from the gate line GL. The display panel 2 may be any one of a liquid crystal display (LCD), an organic light emitting diode display (OLED), and an electrophoretic display (EPD).

The gate driver 4 generates a scan signal synchronized with the data voltages supplied to the plurality of data lines DL, and sequentially supplies the scan signals to the plurality of gate lines GL.

The data driver 6 converts the image data MRGB provided from the timing controller 8 into a gamma compensation voltage to generate a data voltage, and supplies the generated data voltage to the plurality of data lines DL.

The timing controller 8 may include a gate driver (eg, a gate driver) using timing signals such as a vertical synchronization signal Vsync, a horizontal synchronization signal Hsync, a data enable signal Data Enable (DE), and a dot clock DCLK. 4) and the drive timing of the data driver 6 is controlled. The timing controller 8 receives the stretched image data MRGB from the dynamic data stretcher 10, arranges them, and supplies the same to the data driver 6.

The dynamic data stretching unit 10 analyzes the input image data RGB to generate a histogram H, generates a fuzzy belonging first function F1 based on the histogram H, and a fuzzy belonging first function. Comparing and analyzing the second function (F2) and the first to third basis functions (FB1 to FB3) belonging to the fuzzy tuned according to the user's preference (F1) and the conversion function (FC) And stretches the input image data RGB. The dynamic data stretching unit 10 will be described in more detail as follows.

3 is a block diagram of the dynamic data stretching unit 10 shown in FIG. 2.

The dynamic data stretching unit 10 illustrated in FIG. 3 includes a histogram generator 12, a first function generator 14, an operator 16, a second function generator 18, and a data stretch processor. And 20.

The histogram generator 12 receives the image data RGB on a frame basis to generate the histogram H.

The first function generator 14 divides the luminance range into a plurality of luminance regions (hereinafter, referred to as first to third regions). The histogram H is analyzed for each of the first to third regions to calculate a peak frequency value, and a fuzzy belonging first function F1 is generated based on the calculated peak frequency values.

Specifically, as illustrated in FIG. 4, the first function generator 14 obtains a probability density function from the histogram H using Kernel density estimation (1). Peak and valley, that is, the maximum value, the maximum value, and the minimum value are detected ((2)), and a fuzzy belonging first function (F1) of first-order function form having a peak at the detected maximum value is generated. )

Meanwhile, the first function generator 14 may use various methods in addition to the nuclear density estimation method in generating the first function F1 belonging to the fuzzy. For example, the first function generator 14 may estimate the probability density function by connecting intermediate values of the histogram H and generate the fuzzy belonging first function F1 in the same manner as the above method.

The calculating unit 16 compares and calculates the fuzzy belonging first and second functions F1 and F2 to obtain a weight G for each luminance range. Here, the fuzzy belonging second function F2 is a function that a user tunes according to preferences, and is a function that determines the degree of reflection of the fuzzy belonging first function F1 for each of the first to third regions. That is, the fuzzy belonging second function F2 is a constraint function or weight function having a function value between 0 and 1, as shown in FIG. 5.

The first to third basis functions FB1 to FB3 are functions that a user tunes according to preferences. The first basis function FB1 is a function tuned by a user to correct a relatively high luminance image. The basis function FB2 may be a function tuned by a user to correct an image having a uniform luminance, and the third basis function FB3 may be a function tuned by a user to correct an image having a relatively low luminance. The first to third basis functions FB1 to FB3 may vary depending on a user's preference, but will be described as an example.

Referring to FIG. 6, the right image is a relatively high brightness image, the left image is a relatively low brightness image, and the center image is a relatively uniform brightness image. For this image, the user sets the first basis function FB1 in which the slope increases as the luminance increases in response to the image having a relatively high luminance, and the slope in the region where the luminance is low in response to the image having a uniform luminance. The second basis function FB2 in which the slope is gradually increased and the slope is gradually increased in the region having a high luminance is set. Can be set.

As shown in FIG. 7, the second function generator 18 finally reflects the weight range G provided from the calculator 16 to the first to third basis functions FB1 to FB3 to finally convert the transform function. Create (FC).

The data stretching processor 20 stretches and outputs the input image data RGB according to the conversion function FC provided from the second function generator 18.

As described above, in the exemplary embodiment, more detailed image expression is possible by stretching the data based on the result of analyzing the input image data RGB for each luminance region. In addition, the user can set the fuzzy belonging second function (F2) and the first to third basis functions (FB1 to FB3) according to the preference to output an image having the desired contrast ratio and brightness.

It will be apparent to those skilled in the art that various modifications and variations can be made in the present invention without departing from the spirit or scope of the general inventive concept as defined by the appended claims and their equivalents. Will be clear to those who have knowledge of.

H: histogram F1: fuzzy belonging first function
F2: fuzzy belonging second function G: weight by luminance range
FC: conversion functions FB1 to FB3: first to third basis functions

Claims (10)

A display panel configured to display an image by defining pixels at intersections of the plurality of gate lines and the plurality of data lines;
A gate driver for driving the plurality of gate lines;
A data driver driving the plurality of data lines;
Analyze the input image data to generate a histogram, generate a fuzzy belonging first function based on the histogram, and tune the fuzzy belonging second function and the first to the first functions according to the user's preferences. A dynamic data stretching unit for generating a transform function by comparing and analyzing three basis functions and stretching and outputting the input image data according to the transform function;
And a timing controller which controls the cylinder timing of the gate driver and the data driver, and aligns the image data stretched by the stretcher with the driving of the display panel to supply the data driver to the data driver. Device. The method of claim 1,
The dynamic data stretching unit
A histogram generator which receives the image data in frame units and generates a histogram;
Defining a luminance range by dividing the luminance range into a plurality of luminance regions, analyzing the histogram for each of the plurality of luminance regions, calculating a peak frequency value, and generating the fuzzy belonging first function based on the calculated peak frequency values. 1 function generator;
An operation unit which calculates a degree of reflection of the fuzzy belonging first function according to the fuzzy belonging second function and obtains a weight for each luminance range according to a result of the calculation;
A second function generator for generating a conversion function by combining the weights of the luminance ranges with the first to third basis functions;
And a data stretching processor configured to stretch and output the image data by using the conversion function. The method of claim 1,
The first function generator
Probability density function is obtained from the histogram using Kernel density estimation,
And calculating a maximum value, a local maximum value, and a local minimum value of the probability density function to generate the fuzzy belonging first function having a linear function having a point at the maximum value. The method of claim 1,
The fuzzy belonging second function is
And a function value between 0 and 1 in which a reflection ratio of the fuzzy belonging first function is determined based on the tuning value of the user. The method of claim 1,
The first basis function is a function in which the slope increases as the luminance increases.
The second basis function is a function in which the slope increases in a region where the luminance is relatively low, and the slope decreases in a region where the luminance is relatively high,
And the third basis function is a function of decreasing slope as luminance increases. Generating a histogram of the input image data;
Defining a luminance range by dividing the luminance range into a plurality of luminance regions, analyzing the histogram for each of the plurality of luminance regions, calculating a peak frequency value, and generating a fuzzy belonging first function based on the calculated peak frequency values;
Generating a fuzzy belonging second function for determining a degree of reflection of the fuzzy belonging first function for each of the plurality of luminance regions;
Comparing the fuzzy belonging first and second functions and obtaining a weight for each luminance range according to a result of the operation;
Generating first to third basis functions;
Generating a conversion function by combining the weights of the luminance ranges with the first to third basis functions;
Stretching the image data using the transform function;
And displaying the stretched image data on the display panel. The method according to claim 6,
Generating the fuzzy belonging first function
Obtaining a probability density function from the histogram using kernel density estimation;
Computing the maximum value, the local maximum value and the local minimum value of the probability density function, and generating the first function of the fuzzy belonging in the form of a linear function having a point at the maximum value. . The method according to claim 6,
Generating the fuzzy belonging second function
Inputting a tuning value by a user to determine a reflection ratio of the fuzzy belonging first function;
And generating the fuzzy belonging second function having a function value between 0 and 1 in which a reflection ratio of the fuzzy belonging first function is determined based on the tuning value of the user. Driving method. The method according to claim 6,
The first basis function is a function tuned by a user to correct a relatively high luminance image,
The second basis function is a function tuned by a user to correct an image with uniform luminance,
And the third basis function is a function tuned by a user to correct an image having a relatively low luminance. The method according to claim 6,
The first basis function is a function in which the slope increases as the luminance increases.
The second basis function is a function in which the slope increases in a region where the luminance is relatively low, and the slope decreases in a region where the luminance is relatively high,
And the third basis function is a function of gradually decreasing slope as luminance increases.

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