KR20110064094A - Method for outputting image and display system enabling of the method - Google Patents

Abstract

PURPOSE: A method for outputting an image and a display system enabling of the method are provided to improve local dimming effect by measuring the brightness level in an interface region and determining the brightness of an LED device. CONSTITUTION: In a method for outputting an image and a display system enabling of the method, An image analysis part(110) measures the average brightness level from an RGB image signal by division area of an image. The image analysis part measures the intensity level of the border area included in the first division area. An LED brightness determination unit(120) determines the brightness of the LED device according to the brightness level in a boundary area. An LED driver(140) drives LED element according to the brightness of the LED element. A liquid crystal panel shows an image signal.

Description

Image display method and video display device employing the method {METHOD FOR OUTPUTTING IMAGE AND DISPLAY SYSTEM ENABLING OF THE METHOD}

The present invention relates to a video display method and a video display device employing the method, and more particularly, after measuring the luminance level of the boundary region of the divided region of the frame-by-frame image, and corresponding to the adjacent divided region according to the result A video display method for controlling local drive of an LED element and a video display device employing the method.

In general, liquid crystal displays (LCDs) are used in various devices ranging from televisions, notebook computers, desktop monitors, and mobile phones.

Since the LCD does not emit light by itself, a light emitting device capable of illuminating a liquid crystal panel is required to display image information.

The light emitting device of the LCD is coupled to the rear surface of the liquid crystal panel and is called a backlight unit. The backlight unit is a device for providing a light source to the liquid crystal panel by forming a uniform surface light source.

A typical backlight unit includes a light source, a light guide plate, a diffusion sheet, a prism and a protective sheet, and the light source is usually a fluorescent lamp or a light emitting diode such as a mercury cold cathode fluorescent lamp or a light emitting diode. (LED) and the like can be used.

Meanwhile, in connection with the driving device of the light emitting diode, a device capable of realizing a high contrast screen through local dimming of the light emitting diode has been developed.

The driving apparatus of the related art determines a brightness part and a dark part by determining a luminance level of an RGB input signal of an image provided as a backlight, and then uses the information to provide a pulse width modulation signal to a light emitting diode. By outputting, the brightness of the light emitting diode is locally controlled.

 Meanwhile, in the driving apparatus of the related art, as the luminance level of the light emitting diode is determined by the brightness of each region of the division target, the dark image may be darker.

However, the driving apparatus of the related art has a problem in that local dimming efficiency is lowered by performing local dimming on each divided region without considering this even if the luminance of the divided region affects the luminance of another divided region.

That is, when the luminance of a specific divided region is very high, local dimming of other divided regions is not taken into consideration, and thus, there is a problem in that local dimming efficiency of other divided regions is inferior.

Accordingly, by solving the problems of the prior art, by measuring the brightness level of the boundary region of each divided region of the image, and taking this into consideration, the brightness of the LED element corresponding to the divided region adjacent to the boundary region is determined, thereby improving local dimming efficiency. There is an urgent need for development of an image display method that can be enhanced and an image display device employing the method.

The present invention solves the problems of the prior art as described above, by measuring the brightness level of the boundary region of each divided region of the image, and then taking into account the brightness of the LED element corresponding to the divided region adjacent to the boundary region, It is an object of the present invention to provide a video display method capable of increasing dimming efficiency and a video display device employing the method.

The present invention provides a method for measuring a luminance level of a boundary area included in a first divided area of an RGB image signal; And determining brightness of an LED device corresponding to a second divided area adjacent to a boundary of the first divided area according to a result of measuring the luminance level of the boundary area. And driving the LED device according to the brightness of the determined LED device.

The present invention also includes an image analyzer for measuring an average luminance level for each divided region of an image from an RGB image signal, and measuring the luminance level of a boundary region included in the first divided region; And an LED brightness determiner configured to determine brightness of an LED element corresponding to a second divided area adjacent to the boundary of the first divided area according to a result of measuring the luminance level of the boundary area. An LED driver for driving the LED device according to the brightness of the determined LED device; And a liquid crystal panel displaying the video signal.

According to the present invention, after measuring the luminance level of the boundary region for each divided region of the image, the brightness of the LED device corresponding to the divided region adjacent to the boundary region is determined in consideration of this, thereby increasing local dimming efficiency.

Hereinafter, an image display method and an image display apparatus according to the method will be described in detail with reference to the accompanying drawings.

The terms used in the present invention have been selected as general terms widely used as possible in consideration of the functions in the present invention, but may vary according to the intention or custom of a person skilled in the art or the emergence of a new technology. In addition, in certain cases, there is also a term arbitrarily selected by the applicant, in which case the meaning will be described in detail in the description of the invention. Therefore, the terms used in the present invention should be defined based on the meanings of the terms and the contents throughout the present invention, rather than the names of the simple terms.

1 is a diagram illustrating some components of a video display device according to an embodiment of the present invention.

Referring to FIG. 1, an image display device according to an embodiment of the present invention receives an RGB image signal and analyzes image data, and then provides an image analyzer to determine LED brightness to the LED brightness provider 120. 110, an LED driver 140 driving the LED of the backlight according to the determined LED brightness level of the LED brightness determiner 120 determines the brightness of the LED device according to the information provided by the image analyzer 110. do.

The image analyzer 110 divides an image area into a plurality of RGB image signals, and provides information to determine the LED brightness so that the LED brightness determiner 120 determines the brightness of the LED element corresponding to each area. do.

The image analyzer 110 measures an average luminance level for each divided region of the image, measures the luminance level of the boundary region included in each divided region, and then measures the luminance level information of the measured boundary region using the LED brightness determiner ( 120).

The boundary region may be defined as a predetermined region that forms a boundary with another divided region among the divided regions, and the position, width, coordinates, etc. of the boundary region may be variously set according to an embodiment.

The image analyzer 110 measures the luminance level of the boundary region for each divided region of the image.

In this case, the image analyzer 110 may determine the first divided region having the average luminance level of the divided region greater than or equal to a predetermined value and then measure the luminance level of the boundary regions of the first divided regions greater than or equal to the predetermined value.

In addition, the image analyzer 110 measures an average block level of each area of the RGB image signal, an average picture level of the entire image area of the RGB image signal, and then measures the measured information. It may be provided to the LED brightness determining unit 120.

The LED brightness determiner 120 determines the brightness of the LED device corresponding to the second divided area adjacent to the boundary of the first divided area according to the luminance level measurement result of the boundary area.

In this case, the LED brightness determiner 120 stores a look-up table in which the brightness of the LED device corresponding to the second divided area with respect to the luminance level of the boundary area included in the first divided area is stored. The brightness of the LED device for the second divided area corresponding to the brightness level of the boundary area of the first divided area may be determined using the up table.

In this case, the brightness level of the boundary area included in the first partitioned area stored in the look-up table and the brightness of the LED element corresponding to the second partitioned area may be inversely related.

In addition, according to an exemplary embodiment, the LED brightness determiner 120 divides the image by using an average block level of each region of the RGB image signal and an average picture level of an entire image region of the RGB image signal. After determining the brightness of the LED device for each region, the brightness of the LED device for the second divided region may be adjusted or re-determined using the look-up table.

In this case, the LED brightness determining unit 120 may adjust the brightness level of the LED element corresponding to the luminance block level of each divided region of the RGB image signal and the average luminance level of the entire image region of the RGB image signal. The brightness of the LED device according to the measured average brightness level may be determined by using a first table that stores.

In addition, the image display apparatus may include a pixel compensator 150 for compensating a gain value of the image signal according to the average luminance level of the entire image area.

In addition, the image display apparatus may include a driver IC 160 that outputs a control signal to the liquid crystal panel so that the image output according to the RGB image signal output from the image analyzer 110 is performed.

2 is a diagram illustrating an embodiment of determining the brightness of the LED device corresponding to the divided region according to the present invention.

Referring to FIG. 2, a liquid crystal panel 200 displaying an image and an LED backlight 202 providing light to the liquid crystal panel 200 are illustrated.

For local dimming of the LED for the predetermined divided region 201 among the images displayed on the liquid crystal panel 200, the LED brightness determiner 120 uses luminance level information of the boundary region of each divided region of the RGB image signal and the divided region. At least one of an average luminance level and information on an average luminance level of the entire image region of the RGB image signal is used.

According to the LED brightness value determined by the LED brightness determiner 120, the LED driver 140 adjusts the brightness of the LED device that transmits light to the divided region 201.

As a result, local dimming of the LED device is performed in consideration of the result of measuring the luminance level of the boundary region of the divided region of the image.

3 is a diagram illustrating a process of driving an LED device for each divided area according to an exemplary embodiment of the present invention.

Referring to FIG. 3, the image display apparatus according to the exemplary embodiment receives an RGB image signal in step S301, an average luminance level for each of a plurality of divided regions constituting the image in step S302, and The average luminance level of the entire image area is determined.

In operation S303, the image display apparatus measures the luminance level of the boundary region for each divided region.

In this case, the image display device determines that the divided region that may affect the luminance level of another adjacent divided region as the first divided region after determining that the divided region having an average luminance level of each divided region is greater than or equal to a predetermined value. The luminance level of the boundary region of the divided regions determined as the region may be measured.

In operation S303, the image display apparatus determines the brightness of the LED element corresponding to the second divided region adjacent to the boundary surface of the first divided region according to the luminance level measurement result of the boundary region of the first divided region.

According to an exemplary embodiment, the image display apparatus determines the brightness of the LED element for each divided region corresponding to the average luminance level determined for each divided region and the average luminance level of the entire image region, and then, the second display is adjacent to the boundary of the first divided region. The brightness of the LED device corresponding to the divided region may be determined.

In this case, the image display apparatus stores the LED brightness according to the average brightness level of the RGB signal of the entire or divided region of the image in the first table in order to determine the LED brightness of the divided region in the image. The LED brightness corresponding to the RGB average brightness level measured by the image analyzer is read from the first table.

4 is a diagram illustrating a temporary example of a first table for determining LED brightness according to an average brightness level of an RGB signal according to an exemplary embodiment of the present invention.

The x axis of the graph shown in FIG. 4 is the average brightness level of the RGB signal for each divided region, the y axis represents the LED brightness for the divided region, and the z axis represents the average luminance level of the RGB signal for the entire image region. LED brightness is determined when the average brightness level of the RGB signal for each divided region and the average brightness level of the RGB signal for the entire region are determined.

In this case, the first table may set the LED brightness corresponding to the average luminance level of the RGB signal and the average luminance level of the RGB signal for the entire area to various values according to the image modes such as 4A, 4B, and 4C.

On the other hand, after measuring the luminance level of the boundary region for the first divided region having an average luminance level of each divided region equal to or more than a predetermined value, the LED element corresponding to the second divided region adjacent to the first divided region according to the luminance level of the boundary region Determine the brightness of the.

In operation S305, the image display apparatus drives the LED elements corresponding to the divided regions according to the brightness of the LED elements determined in steps S301 and S304.

In operation S306, the image display device performs pixels of the RGB image signal. In this case, the image display device may compensate the gain value of the image signal according to the average luminance level of the entire image area.

According to an exemplary embodiment of the present invention, a correction operation for the RGB signal provided to the liquid crystal panel may be performed along with local dimming of the LED device that provides light to the liquid crystal panel.

That is, when local dimming is performed on the divided region of the image, there may be a region (or a pixel) in which color is to be expressed in the divided region.

In this case, gain is applied to the RGB signal provided to the driver IC 160 according to the brightness level of the entire image, so that incomplete color reproduction due to local dimming of the LED device is not performed.

For example, when local dimming is performed on a specific divided region in an image, even if the average luminance level of the divided region is low and there is a large degree of local dimming, there may be a character or an image to be displayed in the divided region.

In this case, the effect of reducing power consumption due to local dimming is maintained, but the luminance level of the RGB signal provided to the liquid crystal panel is improved to enable color reproduction of the character or image.

Therefore, when the whole image has a bright gray level, the gain value for the RGB signal is set low to prevent the RGB value from becoming more than 255 bits.In the case where the entire image has a dark gray level, a relatively large gain value is used for the RGB signal. In this case, the color is reproduced in the pixel where color reproduction is to be performed even in the area where local dimming is performed.

In operation S307, the image display apparatus displays the gain compensated image signal on the liquid crystal panel.

Therefore, the present invention has the effect of increasing the local dimming efficiency by measuring the brightness level of the boundary region of each divided region of the image, and then determining the brightness of the LED element corresponding to the divided region adjacent to the boundary region in consideration of this. .

FIG. 5 is a diagram illustrating an embodiment of determining brightness of an LED device corresponding to a second divided area according to a first divided area according to the present invention.

Referring to FIG. 5, the image display device according to the exemplary embodiment determines the brightness of the LED element corresponding to the adjacent second divided region 502 according to the luminance level of the boundary region of the first divided region 501. do.

That is, the present invention determines the amount of local dimming of other adjacent divided regions according to the luminance level of the boundary region using the dispersion property of light.

FIG. 6 is a diagram illustrating an embodiment of determining brightness of an LED device corresponding to an adjacent second divided region according to a luminance level of a boundary region of a first divided region according to the present invention.

Referring to FIG. 6, the image display device according to the exemplary embodiment determines the brightness of the LED element corresponding to the adjacent second divided region 602 according to the luminance level of the boundary region 601 of the first divided region. do.

The boundary region may be defined as a predetermined region that forms a boundary with another divided region among the divided regions, and the position, width, coordinates, etc. of the boundary region may be variously set according to embodiments. As shown.

For example, the position of the boundary region may be at least one of the left / right side and the up / down side of the divided region, and when the light of the LED device has a characteristic of spreading a lot of light, the width of the boundary region may be set wide.

In this case, the image display device stores a look-up table in which the brightness of the LED element corresponding to the second divided area with respect to the luminance level of the boundary area included in the first divided area is stored and uses the look-up table to store the first look-up table. The device of the LED brightness of the second divided region corresponding to the luminance level of the boundary region 601 of the divided region is determined.

FIG. 7 is a diagram illustrating an embodiment of determining a compensation constant a corresponding to a luminance level of an included boundary region of a first divided region according to the present invention.

Referring to FIG. 7, the image display apparatus according to the exemplary embodiment of the present invention measures the luminance level of the boundary region of the first divided region and then determines a corresponding compensation constant.

In this case, the luminance level of the boundary region may be an average luminance level of pixels included in the boundary region, and may be a ratio of the average luminance level of the corresponding divided region to the ratio of the average luminance level of the boundary region, that is,

Luminance level of the border area = (average brightness level of the border area) / (average brightness level of the corresponding partition area)

It may be.

FIG. 8 is a diagram illustrating an embodiment of determining LED brightness of a second divided area corresponding to a compensation constant (a) according to the present invention.

Referring to FIG. 8, the image display apparatus according to an exemplary embodiment may determine the LED brightness of the second divided region corresponding to the compensation constant (a).

FIG. 9 is a diagram illustrating an example of a look-up table in which LED brightnesses of adjacent second divided regions are stored according to luminance levels of boundary regions of the first divided region according to an exemplary embodiment of the present invention.

Referring to FIG. 9, the brightness of the LED elements of the second divided area corresponding to the luminance level of the boundary area of each first divided area may be stored in the look-up table, and the image display apparatus may use the display device to display the brightness of the LED elements. After deriving the LED brightness of the 2 divisions, adjust the duty ratio of the PWM signal input to the LED device. In this case, the brightness of the LED element corresponding to the luminance level of the boundary region of the first divided region may be variously determined according to the value of the compensation constant (a).

In this case, the luminance level of the boundary area included in the first divided area and the brightness of the LED element corresponding to the second divided area may be stored in the look-up table in inverse proportion. The higher the luminance level of the boundary region of the first divided region is, the more the second divided region applies local dimming to the first divided region, thereby increasing the efficiency of local dimming.

FIG. 10 is a diagram illustrating an embodiment in which brightness of an LED device corresponding to a second divided area is determined according to a luminance level of the first divided area according to the present invention.

Referring to FIG. 10, as the luminance level of the first divided region 1001 is higher, the brightness of the LED element corresponding to the adjacent second divided region is set smaller (that is, the amount of local dimming is increased), so that the second divided region is increased. Even if the brightness of the LED device corresponding to is set to be small, the light brightness of the LED device reflected in the image 1002 included in the second divided region can be maintained.

As described above, the present invention measures the luminance level of the boundary region of each divided region of the image, and then determines the brightness of the LED element corresponding to the divided region adjacent to the boundary region, thereby maximizing local dimming efficiency. It has an effect.

As described above, the present invention has been described by way of limited embodiments and drawings, and the present invention is not limited to the above-described embodiments, which can be variously modified and modified by those skilled in the art to which the present invention pertains. This is possible. Accordingly, the spirit of the present invention should be understood only by the claims set forth below, and all equivalent or equivalent modifications thereof will belong to the scope of the present invention.

1 is a diagram illustrating a partial configuration of a video display device according to an embodiment of the present invention.

2 illustrates an embodiment of determining brightness of an LED element corresponding to a divided region according to the present invention.

3 is a diagram illustrating a process of driving an LED device for each divided area according to an exemplary embodiment of the present invention.

4 illustrates a temporary example of a first table for determining LED brightness according to an average luminance level of an RGB signal according to an embodiment of the present invention.

FIG. 5 illustrates an embodiment of determining brightness of an LED device corresponding to a second divided area according to a first divided area according to the present invention; FIG.

FIG. 6 illustrates an embodiment of determining brightness of an LED element corresponding to an adjacent second divided region according to a luminance level of a boundary region of the first divided region according to the present invention; FIG.

FIG. 7 illustrates an embodiment of determining a compensation constant a corresponding to a luminance level of an included boundary region of a first divided region according to the present invention. FIG.

8 illustrates an embodiment of determining LED brightness of a second partitioned area corresponding to a compensation constant (a) according to the present invention.

9 illustrates an embodiment of a look-up table in which LED brightnesses of adjacent second divided regions are stored according to luminance levels of boundary regions of the first divided region according to an embodiment of the present invention.

FIG. 10 is a view showing an embodiment in which brightness of an LED element corresponding to a second divided region is determined according to a luminance level of the first divided region according to the present invention; FIG.

<Explanation of symbols for the main parts of the drawings>

110: image analysis unit

120: LED brightness determination unit

140: LED driver

150: pixel compensation unit

160: driver IC

Claims (10)

Measuring a luminance level of a boundary area included in the first divided area of the RGB image signal; And Determining brightness of an LED device corresponding to a second divided area adjacent to a boundary of the first divided area according to a result of measuring the luminance level of the boundary area; And Driving the LED device according to the brightness of the determined LED device; Image display method comprising a. The method of claim 1, Measuring the luminance level of the boundary area included in the first divided area, Measuring an average luminance level for each segment of an image from an RGB image signal; And Determining a first divided area having the average brightness level equal to or greater than a predetermined value; The image display method further comprises. The method of claim 1, Storing a look-up table in which the brightness of the LED device corresponding to the second divided area with respect to the luminance level of the boundary area included in the first divided area is stored; The image display method further comprises. The method of claim 3, wherein The determining of the brightness of the LED device corresponding to the second divided region adjacent to the boundary surface of the first divided region according to the luminance level measurement result of the boundary region, Determining brightness of the LED device corresponding to a brightness level of a boundary area of the first divided area using the look-up table Image display method comprising a. The method of claim 3, wherein And a brightness level of a boundary area included in the first divided area and brightness of an LED element corresponding to the second divided area are inversely related. An image analyzer which measures an average luminance level for each divided region of the image from the RGB image signal and measures the luminance level of the boundary region included in the first divided region; And An LED brightness determiner configured to determine brightness of an LED element corresponding to a second divided area adjacent to a boundary of the first divided area according to a result of measuring the luminance level of the boundary area; An LED driver for driving the LED device according to the brightness of the determined LED device; And A liquid crystal panel displaying the video signal The video display device comprising a. The method of claim 6, The image analyzer, And a first divided area having the average luminance level equal to or greater than a predetermined value. The method of claim 6, The LED brightness determining unit, And a look-up table in which brightnesses of the LED elements corresponding to the second division area are stored with respect to the luminance level of the boundary area included in the first division area. The method of claim 8, The LED brightness determining unit, And determining the brightness of the LED element corresponding to the luminance level of the boundary area of the first divided area by using the look-up table. The method of claim 8, And a brightness level of a boundary area included in the first divided area and a brightness of an LED element corresponding to the second divided area are inversely related.

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