KR101821866B1 - Power saving apparatus and method for displays - Google Patents

Power saving apparatus and method for displays Download PDF

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Publication number
KR101821866B1
KR101821866B1 KR1020150191592A KR20150191592A KR101821866B1 KR 101821866 B1 KR101821866 B1 KR 101821866B1 KR 1020150191592 A KR1020150191592 A KR 1020150191592A KR 20150191592 A KR20150191592 A KR 20150191592A KR 101821866 B1 KR101821866 B1 KR 101821866B1
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blu
luminance
value
current
difference value
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KR1020150191592A
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Korean (ko)
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KR20170080263A (en
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김기두
권태호
김지원
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국민대학교산학협력단
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    • H—ELECTRICITY
    • H04—ELECTRIC COMMUNICATION TECHNIQUE
    • H04N—PICTORIAL COMMUNICATION, e.g. TELEVISION
    • H04N5/00—Details of television systems
    • H04N5/63—Generation or supply of power specially adapted for television receivers
    • H—ELECTRICITY
    • H04—ELECTRIC COMMUNICATION TECHNIQUE
    • H04N—PICTORIAL COMMUNICATION, e.g. TELEVISION
    • H04N5/00—Details of television systems
    • H04N5/44—Receiver circuitry for the reception of television signals according to analogue transmission standards
    • H04N5/57—Control of contrast or brightness
    • H04N2005/44517—

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Abstract

A method of reducing display power according to an exemplary embodiment of the present invention includes determining whether a backlight unit (BLU) of a display is controllable, determining whether a scene change occurs when control of the BLU is possible, Controlling the BLU current according to the determination, dividing the entire image into subblocks when the BLU can not be controlled, and controlling the transmittance to minimize the calculation of the transmittance of the entire image.

Figure R1020150191592

Description

[0001] POWER SAVING APPARATUS AND METHOD FOR DISPLAYS [0002]

[0001] The present invention relates to a display power reduction method and apparatus, and more particularly, to a display power reduction method and apparatus thereof, A display power reduction method and apparatus for achieving power reduction without degrading image quality by estimating a luminance average value for each sub-block and comparing the luminance average value with a luminance average value of each sub-block and applying a transmission rate control algorithm based on the result will be.

The conventional display has a problem that it can not be applied as a display power reduction method when the BLU control can not be performed by only controlling the current of the BLU to reduce the power when the BLU is controllable. In addition, there is a problem that quality deterioration of the image can not be avoided by simply reducing the power by controlling the BLU current. Accordingly, there is a need for a method and an apparatus capable of reducing the power of the display without degrading the image quality by applying another algorithm according to the BLU controllability.

It is an object of the present invention to provide a method and apparatus for reducing display power by applying a power reduction algorithm according to whether a backlight unit (BLU) of a display is controllable.

A method of reducing display power according to an exemplary embodiment of the present invention includes determining whether a backlight unit (BLU) of a display is controllable, determining whether a scene change occurs when control of the BLU is possible, And if BLU control is not possible, dividing the entire image into subblocks and controlling the transmittance to minimize the transmittance calculation of the entire image.

In addition, the step of determining whether the image conversion occurs may include estimating a luminance difference value between a current frame and a previous frame of the image, and comparing the luminance difference value between frames with a predetermined first threshold luminance difference value have.

Determining that a video switching has occurred when the luminance difference value between frames is equal to or greater than a predetermined first threshold luminance difference value; estimating a current frame luminance average value in response to occurrence of video switching; And comparing the luminance value with a threshold luminance value.

If the current frame luminance average value is greater than or equal to the predetermined threshold luminance value, the current of the BLU is controlled to a current corresponding to the threshold luminance value. If the current frame luminance average value is less than the predetermined threshold luminance value, And a step of continuously controlling the current by using a linear equation approximating the current by a section line.

When the luminance difference value between the frames is less than the predetermined first threshold luminance difference value, it is determined that the image switching has not occurred, and the luminance difference value between the frames is determined to be the predetermined second threshold luminance And comparing the difference value with the difference value.

If the luminance difference value between the frames is equal to or greater than the predetermined second threshold luminance difference value, the current of the BLU is continuously controlled by using a linear equation obtained by approximating the current of the BLU by a straight line, And controlling the current of the previous BLU to be maintained if the difference is less than the predetermined second threshold luminance difference value.

The step of controlling the transmittance may include estimating a luminance average value of each sub-block and a luminance average value of the entire image, maintaining the previous transmittance when the luminance average value of each sub-block is equal to or greater than the luminance average value of the entire image, And controlling the transmittance corresponding to the brightness value when the average brightness value is less than the brightness average value of the entire image.

A display power reduction device according to an exemplary embodiment of the present invention includes a BLU controllability determination unit for determining whether power is reduced through BLU (Back Light Unit) control for power reduction of a display, A BLU control unit for controlling the current of the BLU corresponding to the determination result, and a BLU control unit for determining whether a new scene change has occurred, And a transmittance control unit for controlling the transmittance.

Also, the image conversion determination unit obtains the luminance value of the current frame and the previous frame, estimates the luminance difference value between the current frame and the previous frame, compares the interframe luminance difference value with the predetermined first threshold luminance difference value, Can be determined.

In addition, the image conversion determination unit determines that image conversion has occurred when the luminance difference value between frames is equal to or greater than a predetermined first threshold luminance difference value, and the BLU control unit estimates a current frame luminance average value in response to occurrence of image conversion, If the current frame luminance average value is equal to or greater than a predetermined threshold luminance value, the current of the BLU is controlled to a current corresponding to the threshold luminance value, and if the current frame luminance average value is less than the predetermined threshold luminance value, the current of the BLU is approximated to a straight line .

In addition, if the luminance difference value between frames is less than the predetermined first threshold luminance difference value, the image conversion determination unit determines that image conversion has not occurred, and the BLU control unit determines that the image conversion is not performed, Value is compared with a predetermined second threshold luminance difference value, and if the luminance difference value between frames is equal to or greater than a predetermined second threshold luminance difference value, the current of the BLU is continuously controlled by using a linear equation approximated by a straight line for each section, If it is less than the predetermined second threshold luminance difference value, it can be controlled to maintain the current of the previous BLU.

The transmittance control unit divides the entire image into subblocks, estimates a luminance average value of each subblock and a luminance average value of the entire image, and maintains the previous transmittance when the luminance average value of each subblock is equal to or greater than the luminance average value of the entire image , And when the average luminance value of each sub-block is less than the average luminance value of the entire image, the transmittance can be controlled corresponding to the luminance value.

Meanwhile, as an embodiment of the present invention, a computer-readable recording medium on which a program for causing the computer to execute the above-described method may be provided.

In the display power reduction method according to an exemplary embodiment of the present invention, when the BLU control is possible, the BLU current can be controlled according to the occurrence of the image switching, thereby reducing power consumption of the display.

Further, in the display power reduction method according to an exemplary embodiment of the present invention, if the BLU control is not possible, the power of the display can be reduced by applying an algorithm that minimizes the transmittance calculation.

1 is a block diagram of a display power reduction apparatus according to an embodiment of the present invention.
2 is a flowchart briefly showing an algorithm for a display power reduction method according to an embodiment of the present invention.
FIG. 3 is a diagram illustrating a method of dividing an entire image into subblocks in a display power reduction method according to an exemplary embodiment of the present invention. Referring to FIG.
4 is a flowchart illustrating an algorithm for a display power reduction method according to an exemplary embodiment of the present invention.
FIG. 5 is a graph illustrating approximation of a BLU current control section according to a display power reduction method according to an exemplary embodiment of the present invention. Referring to FIG.
FIG. 6 is a graph illustrating an approximation of a section for BLU current control when no image switching occurs in the display power reduction method according to an exemplary embodiment of the present invention. Referring to FIG.

Hereinafter, embodiments of the present invention will be described in detail with reference to the accompanying drawings, which will be readily apparent to those skilled in the art. The present invention may, however, be embodied in many different forms and should not be construed as limited to the embodiments set forth herein. In order to clearly illustrate the present invention, parts not related to the description are omitted, and similar parts are denoted by like reference characters throughout the specification.

The terms used in this specification will be briefly described and the present invention will be described in detail.

While the present invention has been described in connection with what is presently considered to be the most practical and preferred embodiment, it is to be understood that the invention is not limited to the disclosed embodiments. Also, in certain cases, there may be a term selected arbitrarily by the applicant, in which case the meaning thereof will be described in detail in the description of the corresponding invention. Therefore, the term used in the present invention should be defined based on the meaning of the term, not on the name of a simple term, but on the entire contents of the present invention.

When an element is referred to as "including" an element throughout the specification, it is to be understood that the element may include other elements, without departing from the spirit or scope of the present invention. Also, the terms "part," " module, "and the like described in the specification mean units for processing at least one function or operation, which may be implemented in hardware or software or a combination of hardware and software . In addition, when a part is referred to as being "connected" to another part throughout the specification, it includes not only "directly connected" but also "connected with other part in between".

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS Hereinafter, the present invention will be described in detail with reference to the accompanying drawings.

1 is a block diagram of a display power reduction apparatus according to an embodiment of the present invention.

1, a display power reduction apparatus 1000 according to an exemplary embodiment of the present invention includes a BLU (Back Light Unit) controllability determination unit 100, a scene change determination unit 200, a BLU A control unit 300, and a transmittance control unit 400.

The BLU (Back Light Unit) controllability determining unit 100 may be a device for determining power reduction through BLU control of a display in order to reduce power consumption of a display. If BLU control is possible according to the determination of the BLU controllability determining unit 100, a current reduction algorithm through BLU control is performed. If BLU control is impossible, an algorithm for minimizing a transmission rate adjustment operation is performed to reduce power consumption of the display can do.

The scene change determination unit 200 may be a device for determining whether a new image change occurs in the display. That is, the image conversion determination unit 200 can determine occurrence of image conversion when an image is reproduced on the display. For example, when an image is switched on the display, a luminance difference between images occurs, and the images can be judged as different images between frames. Accordingly, the image conversion determination unit 200 estimates the inter-frame luminance difference value (? Y frame ) between the current frame and the previous frame, compares the inter-frame luminance difference value? Y frame with the first threshold luminance difference value, .

Since the image conversion determination unit 200 estimates the inter-frame luminance difference value (? Y frame ) for comparison with the threshold luminance difference value, the luminance conversion unit (not shown), the luminance difference value estimation unit (not shown) A determination unit (not shown), and the like.

The BLU control unit 300 can control the BLU current in accordance with the occurrence of image switching as a determination result of the image switching determination unit 200. That is, when the inter-frame luminance difference value? Y frame is compared with the first threshold luminance difference value and it is determined that the image switching has occurred, the BLU current is controlled by comparing the luminance average value of the current frame with the threshold luminance value, It is possible to control the BLU current by comparing it with the second threshold luminance difference value.

For example, the BLU controller 300 controls the BLU current to be equal to the previous current or the current corresponding to the threshold luminance value so that the BLU current consumption can be minimized without deteriorating the image quality depending on the occurrence of the image switching Or can be continuously controlled using approximated linear equations.

The transmittance control unit 400 can reduce the power of the display by controlling the transmittance of the display so as to minimize the transmittance calculation when BLU control is impossible. For example, in an LCD display or the like, the amount and direction of light to be passed can be controlled by using a polarization filter. By minimizing the transmission rate adjustment calculation, power consumption required for controlling the polarization filter can be reduced.

That is, when the luminance average value of each sub-block is equal to or greater than the total image luminance average value so as to minimize the transmittance adjustment operation, the transmittance control unit 400 can maintain the previous transmittance without the transmittance adjustment operation, thereby reducing power of the display.

If the luminance average value of the sub-blocks is less than the total image luminance average value, the transmittance control unit 400 controls the polarization filter to maintain the image quality, so that the transmittance control unit 400 can control the transmittance corresponding to the luminance value .

2 is a flowchart briefly showing an algorithm for a display power reduction method according to an embodiment of the present invention.

Referring to FIG. 2, FIG. 2 shows an algorithm for a display power reduction method. When BLU control is possible, a power reduction algorithm is performed through BLU control. If BLU control is impossible, the entire screen is divided into sub- The power of the display can be reduced without degrading the quality of the image.

In step S10, the BLU (Back Light Unit) controllability determination unit 100 can determine whether or not BLU control is possible to reduce display power. Since most of the power consumption in the display occurs in the BLU, it is first determined whether the BLU can be controlled, and the next algorithm can proceed.

If the BLU controllability determining unit 100 determines that the BLU can be controlled, the scene change determining unit 200 determines in step S20 whether or not image switching occurs when an image is reproduced on the display . The luminance difference between images varies considerably depending on whether or not the image is switched on the display. For example, if a transition occurs from the current frame to the next frame, the current frame and the next frame may be judged as completely different images due to the luminance difference. For example, if an image is switched on the display, a considerable difference occurs in the luminance value. Therefore, the image conversion determination unit 200 may measure a change in inter-frame luminance and determine whether the image conversion occurs based on the measurement.

In step S30, the BLU control unit 300 can control the BLU current in response to whether or not the image switching occurs. That is, if the BLU can be controlled, the BLU controller 300 can control the BLU current to reduce the display power. The BLU current can be controlled by setting a threshold value according to whether the image conversion occurs. For example, since the difference in luminance value is different between a portion in which the image conversion occurs and a portion in which there is no image conversion and the image continues, the thresholds can be set to be different from each other.

In other words, since the luminance difference is large in the portion where the image conversion occurs, the threshold luminance difference value can be set large, and the portion in which the image conversion does not occur can be set to be small in the threshold luminance difference value. That is, it is possible to set a first threshold luminance difference value (? Y th, scene ) for judging whether or not image conversion has occurred and a second threshold luminance difference value? Y th, frame without image conversion, The luminance difference value? Y th, scene can be set to be larger than the second threshold luminance difference value? Y th, frame . For example, if the first threshold luminance difference value? Y th, scene is set to 50, the second threshold luminance difference value? Y th, frame can be set to about 20. Of course, these values are only one example, and they can be set differently for image environment or power reduction.

That is, the BLU controller 300 determines whether the image switching is to be performed using the first threshold luminance difference value? Y th, scene , and controls the BLU current based on the first threshold luminance difference value? Y th, scene , Can be reduced.

If BLU controllability determination unit 100 determines that BLU control is not possible, then in step S40, transmittance control unit 400 may perform an algorithm to divide the entire image into subblocks.

FIG. 3 is a diagram illustrating a method of dividing an entire image into subblocks in a display power reduction method according to an exemplary embodiment of the present invention. Referring to FIG.

Referring to FIG. 3, the ratio, size, number, and the like of the sub-block 520 can be determined according to the size and resolution of the display. For example, in the case of a 16: 9 display, it can be divided into sub-blocks such as 16x9 or 4x3.

In step S50, the transmittance control unit 400 may control the transmittance to minimize the transmittance calculation. For example, when BLU control is impossible, it is not possible to use a method of controlling BLU current by a display power reduction method. Therefore, it is possible to reduce the power of the display by controlling the transmittance by minimizing the transmittance calculation without degrading the image quality have. That is, since the transmissivity adjustment operation must be minimized without degrading the quality, the transmissivity can be controlled by comparing the average value of the brightness of the entire image and the subblock.

4 is a flowchart illustrating an algorithm for a display power reduction method according to an exemplary embodiment of the present invention.

Referring to FIG. 4, it is determined whether BLU control is possible in the display (S100). If the BLU control is possible, the current reduction algorithm is controlled through BLU control (S110 to S180) It is possible to proceed with the algorithms (S200 to S250) for minimizing the transmittance adjustment operation, thereby reducing the display power without degrading the image quality.

In step S100, the BLU controllability determination unit 100 determines whether BLU control is possible. If it is determined in step S100 that BLU control is possible, in step S110, the image conversion determination unit 200 determines whether the BLU control is enabled The luminance difference between the frame (previous frame) and the subsequent frame can be estimated.

In step S120, the video switching determination unit 200 may compare the luminance difference value (DELTA Yframe ) between the current frame and the previous frame with a predetermined first threshold luminance difference value (DELTA Yth, scene ) If the luminance difference between the previous frame, a predetermined first critical luminance difference value (△ Y th, scene) or more when image conversion is less than determined to have occurred, and the first threshold luminance difference value (△ Y th, scene) the image conversion It can be judged that it has not occurred.

In a case where image switching has occurred, the luminance average value (Y average , present ) of the current frame may be estimated and compared with the predetermined threshold luminance value (Y th, scene ) in step S 130. For example, a predetermined threshold luminance value (Y th, scene ) can be predetermined to a median value of 128 (Y th, scene = 128) in the entire luminance range of 0 to 255, Depending on the environment. That is, the threshold luminance value according to the image environment (Y th, scene) pre luminance value 128, the threshold luminance value (Y th, scene) and a predetermined current luminance of the frame average value (Y average, current) If you decide to 128 and And control the current of the BLU based on the result.

The reason why the threshold luminance value (Y th, scene ) predetermined as the comparison reference is determined as the threshold absolute value (for example, 128) when the video switching occurs is that the reference is changed in one frame in which the video switching occurs It can mean to start. That is, when an image change occurs, the image is compared with a predetermined threshold luminance value (Y th, scene ), which is a new reference, and the BLU current reference can be newly determined and controlled in the image change frame as a result of the comparison.

When image switching occurs, the current control of the BLU controller 300 may be determined by the following equation (1).

Equation 1

If (Y average, current Y th , scene ), I BLU, current = I BLU , scene

else, I BLU, current = αY current + β

Referring to Equation 1, when the luminance average value (Y average , present ) of the current frame is equal to or greater than a predetermined threshold luminance value (Y th , scene ), the BLU controller 300 compares the current of the BLU with a predetermined threshold luminance value Y It controls a current corresponding to the th, scene), and the average brightness value of the current frame (Y average, present) is a predetermined threshold luminance value (Y th, scene) is less than the linear expression I BLU approximated by piecewise linear, current = αY Current BLU current can be continuously controlled using + β.

FIG. 5 is a graph illustrating approximation of a BLU current control section according to a display power reduction method according to an exemplary embodiment of the present invention. Referring to FIG.

Referring to FIG. 5, the x-axis of FIG. 5 represents the luminance value, and the y-axis represents the BLU current value. The α and β values represent the slope and the slice of the linear linear equation. In other words, the values of? And? Can be determined according to the luminance value and the current value at the predetermined end points of each section. For example, if preset for each section, the luminance value and the current value for each section are determined, so that the values of alpha and beta can be determined in advance.

Referring to Equations (1) and (5), since a current larger than the other section is used in the Y th , scene ~ Y max sections, the current consumption may increase when the current greatly changes. And the power consumption of the display can be reduced by decreasing the current consumption by changing the gradient sequentially according to the magnitude of the current.

Average brightness value of the current frame (Y average, present) is a predetermined threshold luminance value or more (Y th, scene), in step S140, BLU control unit 300 is a threshold intensity value determined for the current of the BLU in advance (Y th, scene ) Can be controlled. For example, referring to FIG. 5, when the predetermined threshold luminance value (Y th, scene ) is 128, since the luminance average value (Y average , present ) 510 of the current frame is 128 or more in luminance, current value corresponding to the (Y th, scene) I BLU , can be controlled by the scene (520). That is, if the luminance average value (Y average , present ) of the current frame is equal to or greater than the predetermined threshold luminance value (Yth, scene) in the case where the image conversion occurs, it can be considered that there is a current consumed in the BLU during the reproduction of the current image. controlling a current (I BLU, scene) corresponding to the threshold brightness value (Y th, scene) can be reduced power display.

If the luminance average value (Y average , present ) of the current frame is less than the predetermined threshold luminance value (Y th , scene ), the BLU control unit 300 determines that the BLU current is linearly approximated to a linear Can be continuously controlled by using the above-mentioned method. For example, referring to FIG. 5, a luminance value and a current value at both end points may be determined for each section according to a luminance value Y, and alpha and beta values may be determined in advance for each section. That is, the BLU current can be continuously controlled by using predetermined values of? And? According to the luminance value (Y).

If no image switching occurs, in step S160, a luminance difference value (DELTA Y frame ) between the current frame and the previous frame is estimated, compared with a predetermined second threshold luminance difference value DELTA Yth, frame , Based on the result, the current of the BLU can be controlled.

If the image switching does not occur, the current control of the BLU controller 300 may be determined by the following equation (2).

Equation 2

If (Y frame Y th , frame ), I BLU, current = αY current + β

else, I BLU, current = I BLU, Previous

In other words, referring to Equation (2), when the luminance difference value (Y frame ) between the current frame and the previous frame is equal to or greater than the predetermined second threshold luminance difference value ( Yth , frame ), the BLU controller The BLU current is continuously controlled using the linear equation I BLU approximated by a straight line , current = αY current + β, and the luminance difference value (ΔY frame ) is a predetermined second threshold luminance difference value (ΔY th, frame ) , The previous BLU current (I BLU, previous ) can be maintained to reduce the power of the display.

FIG. 6 is a graph illustrating an approximation of a section for BLU current control when no image switching occurs in the display power reduction method according to an exemplary embodiment of the present invention. Referring to FIG.

Referring to FIG. 6, the x-axis of FIG. 6 represents the luminance value and the y-axis represents the BLU current value. The α and β values represent the slope and the slice of the linear linear equation. In other words, the values of? And? May be determined according to the luminance value and the current value at the predetermined end points at each predetermined section, and may be set in advance for each section. For example, it is possible to set α and β values in advance for each section.

Referring to Equation 2 and 6, the closer to Y max interval the slope of α value can be decreased or reduced the current in the display determined to be a fixed constant, so increasing use of larger electric current than the other section into the Y max. In other words, the luminance difference value (△ Y frame) in order to use the second threshold luminance difference value (△ Y th, frame) the linear equation I BLU, current = αY current + β approximated by piecewise linear on or more, And can be divided into the respective sections according to the luminance value (Y). The larger the luminance value (Y) is, the larger the current is used. Therefore, when the current is greatly changed in the current control, the current consumption may increase, so the slope must be decreased. Current consumption can be reduced.

Also, when the luminance difference value (DELTA Yframe ) is less than the predetermined second threshold luminance difference value (DELTA Yth , frame ), the previous BLU current is maintained so that the current consumption can be reduced without any difference in image quality.

The luminance difference value (△ Y frame) is the second threshold luminance difference value (△ Y th, frame) or more if, in step S170, the I BLU, a linear expression approximating a straight line each section BLU control unit 300 the current = αY current + β can be used to control the current. That is, when the luminance difference value (Y frame ) is determined to be equal to or greater than the second threshold luminance difference value ( Yth , frame ), the BLU controller 300 divides the luminance difference value The BLU current can be controlled according to the value of [beta].

If the luminance difference value? Y frame is less than the second threshold luminance difference value? Y th , frame , the BLU control unit 300 keeps the previous BLU current in step S180, thereby reducing current consumption . That is, there is no image switching the luminance difference value (△ Y frame) In addition, the second threshold luminance difference value power without (△ Y th, frame) to the image quality degradation less so, to keep the previous BLU current without the transmittance adjusting operation It can be a way to reduce it.

In step S100, the BLU controllability determining unit 100 determines whether BLU control is possible. If it is determined in step S200 that the BLU control is impossible, in step S200, the transmittance controller 400 ) Can perform an algorithm that divides the entire image into subblocks. As described above with reference to FIG. 3, the ratio, size, number, and the like of the sub-block 520 can be determined according to the size and resolution of the entire image.

In step S210, the transmittance control unit 400 estimates a luminance average value for each sub-block, estimates the total luminance average value in step S220, compares the average value of each sub-block luminance with the average value of total luminance in step S230, So that the transmittance can be controlled.

If BLU control is not possible, the display transmittance control of the transmittance control unit 400 may be determined by the following equation (3).

Equation 3

If (Y sub Block, average Y total , average ), transmittance current = transmittance transfer

Referring to Equation 3, the luminance average value for each sub-block (sub-Y Block, average) the average brightness value of the entire image (Y total, on average), the transmission controller 400 is to continue to keep the previous transmission, the average brightness value of each sub-block (sub-Y or more If a block, an average) less than the average brightness value (Y total, average) of the entire image may be transmission controller 400 is to control the transmission in response to the luminance value.

For example, the average brightness value of each sub-block (sub-Y Block, average ) is equal to or greater than the average value (Y total , average ) of the entire image, the transmittance calculation need not be performed by keeping the previous transmittance constant, so current consumption required for the polarization filter control can be reduced. That is, it is possible to minimize power consumption by controlling the operation for controlling the transmittance for each frame.

In addition, for each sub-block average brightness value (Y sub Block, an average) may be reduced the power consumption by controlling the brightness of the entire image is less than the average value (Y total, on average), the transmittance corresponding to the luminance value. For example, even if the brightness value changes, the brightness can be kept constant by changing the transmittance corresponding to the brightness value. That is, by controlling the transmittance corresponding to the luminance value, it is possible to reduce the consumed power without deteriorating the image quality. That is, when the luminance value is lowered, the transmissivity of the display is increased corresponding to the lowered luminance value, so that the brightness can be kept constant, so that the current consumption can be reduced while reducing the deterioration of the image quality.

Of each sub-block average brightness value (Y sub Block, average) is not less than the average brightness value of the entire image (Y total, on average), the transmission control section (400 in the step S240) may be to hold a previous transmission. That is, the transmittance control unit 400 can maintain the previous transmittance without calculating the transmittance, thereby minimizing the operation for controlling the transmittance for each frame, thereby reducing the power consumption.

Of each sub-block average brightness value (Y sub Block, average) in this case average brightness value of the entire image (Y total, average) is less than, the transmission control section (400 in the step S250) may control the transmission in response to the illuminance value. That is, the transmittance control unit 400 can control the transmittance by adjusting the polarization filter according to the brightness value, and by keeping the brightness of the display constant, the power consumption can be reduced without degrading the image quality.

The contents of the above-described method can be applied in association with the display power reduction apparatus according to an embodiment of the present invention. Therefore, the description of the same contents as the above-mentioned method with respect to the display power reduction apparatus is omitted.

One embodiment of the present invention may also be embodied in the form of a recording medium including instructions executable by a computer, such as program modules, being executed by a computer. Computer readable media can be any available media that can be accessed by a computer and includes both volatile and nonvolatile media, removable and non-removable media. In addition, the computer readable medium may include both computer storage media. Computer storage media includes both volatile and nonvolatile, removable and non-removable media implemented in any method or technology for storage of information such as computer readable instructions, data structures, program modules or other data.

It will be understood by those skilled in the art that the foregoing description of the present invention is for illustrative purposes only and that those of ordinary skill in the art can readily understand that various changes and modifications may be made without departing from the spirit or essential characteristics of the present invention. will be. It is therefore to be understood that the above-described embodiments are illustrative in all aspects and not restrictive. For example, each component described as a single entity may be distributed and implemented, and components described as being distributed may also be implemented in a combined form.

The scope of the present invention is defined by the appended claims rather than the detailed description and all changes or modifications derived from the meaning and scope of the claims and their equivalents are to be construed as being included within the scope of the present invention do.

100: BLU (Back Light Unit) control availability determination unit
200: scene change judgment unit
300: BLU control unit
400: transmittance control unit
510: luminance average value of current frame (Y average , present )
520: current I BLU corresponding to the threshold luminance value (Y th, scene ) , scene
1000: Display power reduction device

Claims (13)

In a display power reduction method,
Determining whether a backlight unit (BLU) of the display is controllable;
Determining whether a scene change occurs if the BLU is controllable; And
And controlling the BLU current according to the determination whether the image switching has occurred,
Dividing the entire image into subblocks if the control of the BLU is not possible; And
Controlling transmittance to minimize transmittance calculation of the entire image,
The step of controlling the transmittance
Estimating a luminance average value of each sub-block and a luminance average value of the entire image; And
A previous transmittance is maintained when the luminance average value of each sub-block is equal to or greater than the luminance average value of the whole image, and when the luminance average value of each sub-block is less than the luminance average value of the whole image, the transmittance is controlled in accordance with the luminance value ≪ / RTI >
Wherein dividing the sub-blocks into sub-blocks comprises dividing an entire image into sub-blocks by determining a ratio, a size, and a number of sub-blocks according to a size and a resolution of the display.
The method according to claim 1,
The step of determining whether the image switching occurs may include: estimating a luminance difference value between a current frame and a previous frame of the image; And
And comparing the luminance difference value between the frames with a predetermined first threshold luminance difference value.
3. The method of claim 2,
Estimating a current frame luminance average value in response to the occurrence of the image switching when the luminance difference value between the frames is equal to or greater than the predetermined first threshold luminance difference value; And
And comparing the current frame luminance average value with a predetermined threshold luminance value.
The method of claim 3,
Wherein the controlling of the BLU current includes controlling a current of the BLU to a current corresponding to the threshold luminance value if the current frame luminance average value is greater than or equal to a predetermined threshold luminance value and if the current frame luminance average value is less than a predetermined threshold luminance value And continuously controlling the current of the BLU by using a linear equation obtained by approximating the current of the BLU by a straight line for each section.
3. The method of claim 2,
And determines that the image switching does not occur when the luminance difference value between the frames is less than the predetermined first threshold luminance difference value and determines that the luminance difference value between the frames does not correspond to the predetermined second And comparing the threshold value with a threshold brightness difference value.
6. The method of claim 5,
Wherein the step of controlling the BLU current continuously controls the current of the BLU using a linear equation obtained by approximating the current of the BLU to a straight line when the luminance difference value between the frames is equal to or greater than a predetermined second threshold luminance difference value, Controlling the current of the previous BLU to be maintained if the value is less than the predetermined second threshold luminance difference value.
delete A display power reduction apparatus comprising:
A BLU controllability determination unit for determining whether power is reduced through BLU (Back Light Unit) control for power reduction of the display;
An image switching determination unit for determining whether a new scene change occurs in the display when the BLU control is enabled;
A BLU controller for controlling a current of the BLU in accordance with a result of the determination whether the new image conversion occurs; And
And a transmittance control unit for controlling a transmittance of the display for power reduction of the display when the BLU control is impossible,
The transmittance control unit divides the entire image into subblocks by determining the ratio, size, and number of subblocks according to the size and resolution of the display, estimates a luminance average value of each subblock and a luminance average value of the entire image, The previous transmittance is maintained when the average luminance value of each sub-block is equal to or greater than the luminance average value of the entire image, and the transmittance is controlled according to the luminance value when the luminance average value of each sub-block is less than the luminance average value of the whole image A display power reduction device.
9. The method of claim 8,
The image conversion determination unit obtains a luminance value of a current frame and a previous frame, estimates a luminance difference value between the current frame and a previous frame, compares the interframe luminance difference value with a predetermined first threshold luminance difference value, And determines whether or not the switching has occurred.
10. The method of claim 9,
Wherein the image switching determination unit determines that the image switching has occurred when the luminance difference value between the frames is equal to or greater than a predetermined first threshold luminance difference value and the BLU control unit estimates a current frame luminance average value in response to the occurrence of the image switching, If the current frame luminance average value is greater than or equal to a predetermined threshold luminance value, controlling the current of the BLU to a current corresponding to the threshold luminance value, and if the current frame luminance average value is less than a predetermined threshold luminance value, Wherein the control unit continuously controls the display apparatus using the display apparatus.
10. The method of claim 9,
Wherein the image switching determination unit determines that the image switching does not occur when the luminance difference value between the frames is less than a predetermined first threshold luminance difference value and the BLU control unit determines that the image switching is not performed, The luminance difference value is compared with a predetermined second threshold luminance difference value, and if the luminance difference value between the frames is equal to or greater than the predetermined second threshold luminance difference value, the current of the BLU is approximated by a straight line for each interval, And controls the current of the previous BLU to be maintained if the difference is less than the predetermined second threshold luminance difference value.
delete A computer-readable recording medium on which a program for implementing the method of any one of claims 1 to 6 is recorded.
KR1020150191592A 2015-12-31 2015-12-31 Power saving apparatus and method for displays KR101821866B1 (en)

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Citations (2)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
KR100810506B1 (en) * 2006-10-17 2008-03-07 삼성전자주식회사 Display apparatus
JP2010509628A (en) * 2006-11-09 2010-03-25 コーニンクレッカ フィリップス エレクトロニクス エヌ ヴィ Liquid crystal display system and method

Patent Citations (2)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
KR100810506B1 (en) * 2006-10-17 2008-03-07 삼성전자주식회사 Display apparatus
JP2010509628A (en) * 2006-11-09 2010-03-25 コーニンクレッカ フィリップス エレクトロニクス エヌ ヴィ Liquid crystal display system and method

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