KR20110064548A - Method for outputting image using illuminance and display system enabling of the method - Google Patents

Abstract

PURPOSE: A method for outputting image using illuminance and a display system enabling of the method are provided to implement dynamic color contrast by performing a local dimming according to a sensing result. CONSTITUTION: In a method for outputting image using illuminance and a display system enabling of the method, a An illuminance sensor(130) detects illuminance and generates illuminance sensing information. The illuminance sensor transmits the illuminance sensing information to an LED brightness determination unit. An LED brightness determination unit(120) receives the illuminance sensing information from the illuminance sensor. The LED brightness determination unit determines the brightness of the LED device corresponding to a division area which is included in the image of an RGB image signal by using the illuminance sensing information. An LED driver(140) drives the LED element according to the brightness of the LED element.

Description

Image display method using illuminance sensing and image display device employing the method {METHOD FOR OUTPUTTING IMAGE USING ILLUMINANCE AND DISPLAY SYSTEM ENABLING OF THE METHOD}

The present invention relates to an image display method and an image display apparatus employing the method, and more particularly, to an image display method for determining the brightness of an LED element for each divided region of an image signal by sensing illuminance and an image employing the method. It relates to a display device.

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.

On the other hand, the driving apparatus of the prior art has a problem that the color contrast can not be dynamically implemented according to the surrounding environment by performing local dimming, without considering the illumination of the surrounding environment.

Therefore, by solving the problems of the prior art, by sensing the illumination, and performing local dimming according to the result of the illumination sensing, by using an image display method and a method that can dynamically implement the color contrast in consideration of the surrounding environment Development of a video display device is urgently requested.

The present invention solves the problems of the prior art as described above, and after sensing the illuminance, by performing local dimming according to the result of the illumination sensing, image display method and method that can dynamically implement color contrast in consideration of the surrounding environment It is an object of the present invention to provide a video display device employing the same.

An image display method of an image display apparatus according to an embodiment of the present invention comprises the steps of receiving an RGB image signal; Receiving illumination sensing information from an illumination sensor included in the video display device; Determining brightness of an LED device corresponding to a divided region included in the image by using the illumination sensing information; And driving the LED device according to the brightness of the determined LED device.

In addition, the image display device according to another embodiment of the present invention includes an illumination sensor for sensing the illumination, generates the illumination sensing information, and transmits the generated illumination sensing information to the LED brightness determination unit; An LED brightness determiner which receives illuminance sensing information from the illuminance sensor and determines brightness of an LED element corresponding to a divided region included in an image of an RGB image signal using the illuminance sensing information; An LED driver for driving the LED device according to the brightness of the determined LED device; And a liquid crystal panel displaying the RGB image signal.

According to the present invention, after sensing the illuminance, local dimming is performed according to the result of the illuminance sensing, and thus, color contrast can be dynamically realized in consideration of the surrounding environment.

For example, the present invention performs local driving which is less sensitive to the average luminance level of the divided region in an environment where the illumination is dark, and performs local driving which is very sensitive to the average luminance level of the divided region in the environment where the illumination is dark, so that the illumination intensity is dark. In the environment, the brightness of each of the divided areas is slightly less, and in the environment of the bright light, the difference in the brightness of each of the divided areas is prominent, thereby allowing the user to dynamically view the video signal.

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 exemplary embodiment of the present invention generates an illumination sensing result by sensing an illumination and transmits the illumination sensing result to the LED brightness determiner 120, an RGB. After receiving the image signal and analyzing the image data, according to the information provided by the image analyzer 110, the image analyzer 110, which provides information to determine the LED brightness to the LED brightness providing unit 120 of the LED device LED brightness determination unit 120 for determining the brightness includes a LED driver 140 for driving the LED of the backlight according to the determined LED brightness level.

The illuminance sensor 130 senses the illuminance of the surrounding environment of the image display device to generate an illuminance sensing result, and transmits the illuminance sensing result to the LED brightness determiner 120.

The illuminance sensor 130 measures the brightness of the surrounding environment by measuring the total luminous flux incident on the unit area. The illuminance is inversely proportional to the square of the distance from the light source and is proportional to cos θ when the angle between the normal of the plane and the incident light is θ.

Thus, if a face is positioned to receive the same light from two light sources, then the position of the face is adjusted so that both illuminances are the same, so that the ratio of the intensity of light from the two light sources is given as the ratio of the square of the distance from each light source to the face. The illuminance sensor 130 measures illuminance using this principle.

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.

In this case, the information for determining the LED brightness may be at least one of an average block level of each region of the RGB image signal and an average picture level of the entire image region of the RGB image signal.

The LED brightness determiner 120 determines the brightness of the LED element corresponding to each divided region by using the information for determining the LED brightness and the illumination sensing information.

In this case, the LED brightness determining unit 120 corresponds to the divided region included in the image by using the received illuminance sensing information when the currently received illuminance sensing information differs from the previously received illuminance sensing information by a predetermined range or more. The brightness of the LED device can be determined. This is to improve the local dimming efficiency by allowing the local dimming to be changed dynamically only when the illuminance of the surrounding environment is changed and the difference is more than a certain range.

According to an exemplary embodiment, the LED brightness determiner 120 may adjust a brightness of the divided area according to the illumination sensing result by compensating a gain value different from the brightness of the LED device according to the received illumination sensing information range.

In addition, the LED brightness determiner 120 stores a look-up table for storing the brightness of the LED device corresponding to the divided area corresponding to the illuminance sensing information, and uses the look-up table to divide the look-up table. The brightness of the LED device corresponding to the area may be determined to adjust the brightness of the divided area according to the illumination sensing result.

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 detects an average luminance level of each divided region of the RGB image signal, the RGB as a result of illuminance sensing. Information about an average luminance level of the entire image region of the 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 for transmitting light to the divided region 301.

As a result, local dimming of the LED device is performed in consideration of the result of sensing the luminance level and illuminance according to the RGB signal of all or a part 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 an exemplary embodiment receives an RGB image signal in step S301.

The RGB image signal includes a video signal received in the form of a broadcast signal, received through the Internet, or stored in internal / external storage means.

In operation S302, the image display apparatus measures an average luminance level and an average luminance level of the entire image region for each of the plurality of divided regions constituting the image.

Next, the image display device generates illuminance sensing information from the illuminance sensor in step S303. The generated illuminance sensing information is transmitted to the LED brightness determiner.

In operation S304, the image display apparatus determines the brightness of the LED element corresponding to each divided area by using the illumination sensing information.

In this case, when the received illuminance sensing information is different from the previously received illuminance sensing information by a predetermined range or more, the image display device uses the received illuminance sensing information to display the brightness of the LED element corresponding to the divided region included in the image. As described above, it is possible to increase the efficiency of local dimming.

The image display apparatus may further determine brightness of the LED element corresponding to the divided region of the image by additionally using the average luminance level of the entire region or the average luminance level of each divided region.

At this time, in order to determine the LED brightness of the divided region 201 in the image according to the embodiment, the image display device 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. After reading the LED brightness corresponding to the RGB average brightness level measured by the image analyzer 110 from the first table, the final LED brightness may be determined by reflecting the illumination intensity sensing information.

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, as shown by reference numerals 401, 402, and 403, 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 mode. have.

Next, the image display device compensates for a gain value different from the brightness of the LED element according to the range of the received illumination sensing information.

In this case, the image display device stores a look-up table that stores the brightness of the LED device corresponding to the divided area corresponding to the illumination sensing information, and then uses the look-up table to display the LED device corresponding to the divided area. The brightness of the can be determined.

FIG. 5 is a diagram illustrating an embodiment of a look-up table in which the brightness of the LED device for each divided region is determined according to the illumination sensing result according to the present invention. At this time, the look-up table may be stored in the LED brightness determining unit or in a separate storage means.

Referring to FIG. 5, the image display apparatus according to the exemplary embodiment may differently determine the local dimming amount of the LED element corresponding to the divided region according to the sensed illuminance information.

For example, when the illuminance sensing information is in the first range (for example, 0 to 100 lux), it is determined that the viewing environment is very dark, and the local driving amount (local dimming amount) corresponding to the average luminance level of the divided region is determined. Is controlled as shown by reference numeral 501.

As another example, when the illuminance sensing information is in the second range (for example, 100 to 200 lux), it is determined that the viewing environment is a little dark, and the local driving amount (local dimming amount) corresponding to the average luminance level of the divided region is determined. ) Is controlled as shown by reference numeral 502.

As another example, when the illuminance sensing information is in the third range (eg, 200-300 lux), it is determined that the viewing environment is bright, and thus, the local driving amount (local dimming amount, LED) corresponding to the average luminance level of the divided region is determined. May be inversely proportional to brightness), as indicated by reference numeral 503.

Therefore, as shown in FIG. 5, when the local driving amount of the LED device is controlled according to the illumination sensing information, local driving is less sensitive to the average luminance level of the divided region in the dark illumination environment, and the average of the divided regions in the light illumination environment. Local driving, which is very sensitive to the luminance level, allows the brightness of each segment to be less severe in low-light conditions and the brightness difference between the regions in the low-light environment to be noticeable, allowing the user to dynamically watch video signals. There is.

5 illustrates an embodiment in which a local driving amount of an LED element corresponding to an average luminance level of a divided region is controlled according to illuminance sensing information, but in addition, to consider an average luminance level of an entire region of an image. The first table may be additionally used. That is, the LED brightness value for each divided region may be finally determined by additionally considering the local driving amount information determined in FIG. 5 in addition to the LED brightness value determined for each divided region in the graph of FIG. 4.

In operation S305, the image display device drives the corresponding LED elements for each divided area according to the brightness of the LED elements determined in operation 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.

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

 Accordingly, the present invention determines the local dimming amount for each divided region by using the illumination sensing result, thereby realizing a high contrast screen through local dimming of the light emitting diode for the image, while the user divides according to the ambient illumination. By allowing the dynamic high contrast effect to be felt for each area, there is an effect that can respond to various needs of the user.

As described above, the present invention has been described by way of limited embodiments and drawings, but 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. Modifications are 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 is a diagram illustrating an embodiment of a look-up table in which brightness of LED elements for each divided area is determined according to an illuminance sensing result 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

130: Ambient Light Sensor

140: LED driver

150: pixel compensation unit

160: driver IC

Claims (10)

In the video display method of the video display device, Receiving an RGB image signal; Receiving illumination sensing information from an illumination sensor included in the video display device; Determining brightness of an LED device corresponding to a divided region included in the image by using the illumination sensing information; And Driving the LED device according to the brightness of the determined LED device; An image display method of a video display device comprising a. The method of claim 1, Determining the brightness of the LED device corresponding to the divided region included in the image by using the illumination sensing information, Determining the brightness of the LED device corresponding to the divided region included in the image by using the received illuminance sensing information when the received illuminance sensing information differs from the previously received illuminance sensing information by a predetermined range or more. An image display method of a video display device comprising a. The method of claim 1, Measuring an average luminance level of all regions of the image of the RGB image signal or an average luminance level of each divided region included in the image; More, Determining the brightness of the LED device corresponding to the divided region included in the image by using the illumination sensing information, Determining brightness of the LED element corresponding to the divided region of the image by additionally using the average luminance level of the entire region or the average luminance level of each divided region. The video display method of the video display device further comprising. The method of claim 1, Determining the brightness of the LED device corresponding to the divided region included in the image by using the illumination sensing information, Compensating for a gain value different from the brightness of the LED element according to the received illuminance sensing information range; The method of claim 1, Storing a look-up table for storing brightness of an LED device corresponding to the divided area corresponding to the illumination sensing information; Determining the brightness of the LED device corresponding to the divided region included in the image by using the illumination sensing information, Determining brightness of an LED device corresponding to the divided region by using the look-up table Image display method comprising a. In the video display device, An illuminance sensor detecting illuminance, generating illuminance sensing information, and transmitting the generated illuminance sensing information to an LED brightness determiner; An LED brightness determiner which receives illuminance sensing information from the illuminance sensor and determines brightness of an LED element corresponding to a divided region included in an image of an RGB image signal using the illuminance sensing information; An LED driver for driving the LED device according to the brightness of the determined LED device; And Liquid crystal panel for displaying the RGB image signal The video display device comprising a. The method of claim 6, The LED brightness determining unit, when the received illuminance sensing information is different from the previously received illuminance sensing information by a predetermined range or more, using the received illuminance sensing information, brightness of an LED element corresponding to the divided region included in the image. And a video display device. The method of claim 6, An image analyzer which measures an average luminance level of all regions of the image of the RGB image signal or an average luminance level of each divided region included in the image. More, And the LED brightness determiner determines the brightness of the LED element corresponding to the divided region of the image by additionally using the average luminance level of the entire region or the average luminance level of each divided region. The method of claim 6, And the LED brightness determiner compensates for a gain value different from the brightness of the LED element according to the received illuminance sensing information. The method of claim 6, The LED brightness determining unit stores a look-up table that stores the brightness of the LED device corresponding to the divided area corresponding to the illuminance sensing information. And a brightness of the LED device corresponding to the divided area is determined by using the look-up table.

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