KR20160007319A - Electronic apparatus and Method for controlling the electronic apparatus thereof - Google Patents

Abstract

Provided are an electronic apparatus for expanding a dynamic range, and a control method thereof. The method for controlling an electronic apparatus includes: determining representative colors of a plurality of pixels configuring an image frame by analyzing a received image frame; calculating an input dynamic range for the representative colors based on brightness information of the received image frame; expanding a dynamic range for the representative colors by calculating a gain value corresponding to the representative colors based on at least one of the brightness information of the received image frame and display characteristics of the electronic apparatus; and outputting an image frame having adjusted brightness based on the expanded dynamic range.

Description

BACKGROUND OF THE INVENTION 1. Field of the Invention [0001] The present invention relates to an electronic apparatus and a control method thereof,

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an electronic apparatus and a control method thereof, and more particularly, to an electronic apparatus and a control method thereof that extend a dynamic range based on a color distribution of an input image frame and a gamut representation range of an output apparatus.

Modern electronic devices expand the dynamic range when outputting images, depending on the needs of users who demand sharp image quality. Conventional electronic devices extend the dynamic range by adjusting the maximum and minimum range of the histogram according to the brightness information of the image. Specifically, an existing electronic device analyzes an inputted image, generates a histogram based on the analysis result, explains an extended range of the dynamic range according to brightness information, and extends the histogram based on the extended range of the dynamic range , Providing users with clearer picture quality.

That is, conventionally, the dynamic range is expanded by determining the minimum and maximum values of the histogram according to the brightness information of the image. However, when there are letterboxes, texts, or the like including black or white components in an image frame, the dynamic range of the image frame has a value close to the maximum dynamic range of 0 to 255 (in the case of a system of 8 bits). As a result, it is difficult to expand the dynamic range substantially, resulting in a problem that the improvement range of image quality is not large.

SUMMARY OF THE INVENTION The present invention has been made to solve the above-mentioned problems, and it is an object of the present invention to provide a display device capable of providing a clearer image quality to a user by expanding a dynamic range by color in consideration of information about an input image and a color expression range of an electronic device And to provide a control method therefor.

According to another aspect of the present invention, there is provided a method of controlling an electronic device, comprising: analyzing an input image frame to determine a representative color of a plurality of pixels constituting the image frame; Calculating an input dynamic range for a plurality of representative colors based on the brightness information of the input image frame; Expanding a dynamic range for each representative color based on at least one of brightness information of the input image frame and display characteristics of the electronic device; And outputting an image frame whose brightness is adjusted based on the extended dynamic range.

The determining of the representative color may include determining at least one of a hue value and a saturation value for the plurality of pixels; Determining whether the plurality of pixels are chromatic or achromatic based on at least one of the hue and saturation values; And determining a representative color of each of the pixels determined to be chromatic color among the plurality of pixels.

The determining whether the chromatic color is a chromatic color or not may include determining a pixel whose color value is not defined or the chroma value is less than a preset value as an achromatic color, It can be judged.

The step of calculating the input dynamic range may include analyzing the input image frame to determine a maximum brightness value and a minimum brightness value of representative colors included in the input image frame, Determining a minimum value among the minimum brightness values for the representative colors as a minimum brightness value of the image frame; Determining a minimum brightness value of the image frame as a minimum value of the representative colors and determining a maximum brightness value of each of the representative colors included in the image frame as a maximum value of the representative colors to determine an input dynamic range of the plurality of representative colors, And a step of calculating the number of steps.

Also, the step of expanding the dynamic range may include calculating a maximum gain value for each representative color using a ratio of a maximum brightness value that can be output maximum for each representative color and a maximum brightness value of each representative color included in the image frame The method comprising the steps of:

The step of expanding the dynamic range may include: determining a weight for each representative color based on color characteristics and user preferences that the electronic device can output; Calculating a final gain value for each representative color by applying a weight to the calculated maximum gain value; And extending the dynamic range by the representative color by applying the final gain value to the input dynamic range for each representative color.

In addition, the step of determining the weights may determine the weights by the representative colors in consideration of the maximum gain value of adjacent representative colors.

The step of expanding the dynamic range may further include calculating a gain value between the representative colors by interpolating gain values for the representative color.

The method of claim 1, further comprising: selecting an area for expanding a dynamic range of the input image frame, wherein the step of determining a representative color of the plurality of pixels comprises: Can be determined.

According to another aspect of the present invention, there is provided an electronic device including: an input unit receiving an image frame; A representative color determining unit for analyzing the input image frame to determine a representative color of a plurality of pixels constituting the image frame; An input dynamic range calculation unit for calculating an input dynamic range for a plurality of representative colors based on the brightness information of the input image frame; A dynamic range extension unit for expanding the dynamic range by the representative color based on at least one of the brightness information of the input image frame and the display characteristic of the electronic device; And an output unit for outputting an image frame whose brightness is adjusted based on the extended dynamic range.

The representative color determining unit may determine at least one of a hue value and a saturation value for the plurality of pixels and determine whether the plurality of pixels are chromatic or achromatic based on at least one of the hue value and the saturation value And determine a representative color of each of the pixels determined to be chromatic color among the plurality of pixels.

The representative color determining unit may determine that the pixel whose color value is not defined or whose saturation value is less than or equal to a preset value is an achromatic color, and the pixel whose saturation value exceeds a predetermined value is a chromatic color.

The input dynamic range calculator may analyze the input image frame to determine a maximum brightness value and a minimum brightness value for each representative color included in the input image frame, and determine a minimum brightness value Determining a minimum value of the image frame as a minimum brightness value of the image frame, determining the minimum brightness value of the image frame as a minimum value of the representative colors, and determining a maximum brightness value of each representative color included in the image frame as the representative color The input dynamic range of the plurality of representative colors can be calculated.

Also, the dynamic range extension unit may calculate the maximum gain value for each representative color using a ratio of a maximum brightness value that can be output maximum for each representative color and a maximum brightness value of each representative color included in the image frame .

The dynamic range extension unit may determine a weight for each representative color based on color characteristics and user preferences that can be output by the electronic device and apply a weight to the calculated maximum gain value to calculate a final gain And applying the final gain value to the input dynamic range to extend the dynamic range by the representative color.

In addition, the dynamic range extending unit may determine a weight for each representative color in consideration of the maximum gain value of adjacent representative colors.

The dynamic range extension unit may calculate a gain value between the representative colors by interpolating gain values for the representative color.

The apparatus may further include an area selector for selecting an area for expanding the dynamic range of the input image frame, and the representative color determining unit may determine a representative color of a plurality of pixels included in the selected area .

As described above, according to various embodiments of the present invention, it is possible to provide a clearer image quality to the user by expanding the dynamic range according to color by considering the information about the input image and the color expression range of the electronic device. In addition, there is an effect of improving the phenomenon of being shifted to the surrounding color without being extended at the gamut boundary.

1 is a block diagram showing the configuration of an electronic device according to an embodiment of the present invention;
FIGS. 2A and 2B are graphs for explaining the input brightness distribution and the output brightness distribution for each representative color according to an exemplary embodiment of the present invention;
3 is a diagram for explaining a method of calculating a gain value by interpolating a gain value for each representative color according to an embodiment of the present invention;
FIGS. 4 and 5 are diagrams for explaining a 3-D cube interpolation input value and an actual application example according to an embodiment of the present invention;
6 is a diagram for explaining a 3D interpolation operation according to an embodiment of the present invention;
7 is a diagram for comparing an input image and an output image according to a conventional dynamic range expansion method,
8 is a diagram for comparing an input image and an output image according to a range extending method of the present invention,
FIG. 9 is a flowchart illustrating a method for expanding a dynamic range for each representative color according to an embodiment of the present invention; FIG.
10 is a block diagram showing the configuration of an electronic device according to another embodiment of the present invention.

These embodiments are capable of various modifications and various embodiments, and specific embodiments are illustrated in the drawings and described in detail in the description. It is to be understood, however, that it is not intended to limit the scope of the specific embodiments but includes all transformations, equivalents, and alternatives falling within the spirit and scope of the disclosure disclosed. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS In the following description of the embodiments of the present invention,

The terms first, second, etc. may be used to describe various elements, but the elements should not be limited by terms. Terms are used only for the purpose of distinguishing one component from another.

The terminology used herein is for the purpose of describing particular embodiments only and is not intended to limit the scope of the claims. The singular expressions include plural expressions unless the context clearly dictates otherwise. In this application, the terms "comprise", "comprising" and the like are used to specify that there is a stated feature, number, step, operation, element, component, or combination thereof, But do not preclude the presence or addition of features, numbers, steps, operations, components, parts, or combinations thereof.

In the embodiment, 'module' or 'sub' performs at least one function or operation, and may be implemented in hardware or software, or a combination of hardware and software. In addition, a plurality of 'modules' or a plurality of 'parts' may be integrated into at least one module except for 'module' or 'module' which need to be implemented by specific hardware, and implemented by at least one processor (not shown) .

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS Hereinafter, embodiments of the present invention will be described in detail with reference to the accompanying drawings. Referring to the accompanying drawings, the same or corresponding elements are denoted by the same reference numerals, and a duplicate description thereof will be omitted.

1 is a block diagram showing the configuration of an electronic device 100 according to an embodiment of the present invention. 1, the electronic device 100 includes an input unit 110, a representative color determination unit 120, a dynamic range expansion unit 130, a gain value calculation unit 140, and an output unit 150 do. At this time, the electronic device 100 may be implemented by various devices such as a digital TV, a desktop PC, a notebook PC, a tablet PC, a smart phone, a kiosk, a printing device, and the like capable of outputting image frames.

The input unit 110 receives an image frame. At this time, the input image frame can be represented by one of RGB model, YCbCr model, and HSV model.

At this time, the RGB model is the most noble color model, and the color is represented by a combination of three components of Red, Green, and Blue. In the RGB model, R = G = B = 0 for black, R = G = B = 255 for white, R = 255, G = B = 0 for red, and R = G = 255 and B = 0 for yellow do. When R = G = B, it becomes an achromatic gray color. Since each of R, G, and B can have a value between 0 and 255, an RGB color model can represent a total of 256 * 256 * 256 = 16,777,216 colors.

The YCbCr model is a color model that separates and expresses the brightness component (Y) and the color difference information (Cb, Cr) in the RGB color. In the YCbCr model, Y, Cb, and Cr have values between 0 and 255, respectively. When Y becomes larger, it becomes brighter overall. When Y becomes smaller, it becomes darker overall. The YCbCr model is a color model used in MPEG. It uses a large number of bits (resolution) for Y and a low number of bits for Cb and Cr using the fact that human eyes are sensitive to brightness difference but relatively insensitive to color difference Compress video in a manner that allocates. Therefore, when YCbCr model is used for processing video data, there is no need to perform color conversion separately. The YCbCr model is also called the YUV model.

The HSV model expresses color with three components: Hue, Saturation, and Value. Hue indicates what kind of color the color is (for example, red color, blue color, etc.), and saturation indicates how bright (pure) the color is, Represents the intensity of the color. For the HSV model, each of H, S, and V is expressed as a value between 0 and 255. The H value represents a kind of color, so the size is meaningless and represents a simple index. An S value of 0 indicates that the color is achromatic (gray color), and 255 indicates the sharpest (pure) color. The smaller the V value, the darker the color, the brighter the larger the color. The HSV color model has a conic shape and a cylindric shape as shown in the figure.

The representative color determination unit 120 analyzes the input image frame to determine a representative color of a plurality of pixels constituting the image frame.

Specifically, the representative color determination unit 120 may determine at least one of a hue value (H) and a chroma value (Chroma) for a plurality of pixels included in the input image frame. At this time, the representative color determining unit 120 selects one of the following Equation 1 to Equation 4 according to the complexity tolerance of the electronic device 100, And a saturation value (Chroma).

At this time, the Cb and Cr values may be the same as those defined in BT 601 or BT 709. For example, according to the BT 601 formula, Cb is -0.1482 * R -0.2909 * G + 0.4392 * B, Cr is 0.4392 * R -0.3678 * G-0.0714 * B And Cb is -0.1687 * R -0.3313 * G + 0.5 * B and Cr is 0.5 * R -0.4187 * G-0.0813 * B according to the BT 709 formula.

At this time,? Is (2 * R-G-B) / 2 and? Is sqrt (3) / 2 * (G-B).

The representative color determination unit 120 may determine whether a plurality of pixels are chromatic color or neutral color based on the hue value and the chroma value. Specifically, the representative color determination unit 120 determines that the pixel whose chroma value is equal to or less than a predetermined value is achromatic color when the hue value H is not defined (i.e., when R = G = B) It can be determined that the pixel having the set value or more is a chromatic color.

The representative color determination unit 120 may determine a representative color for the pixels determined to be pseudo colors among a plurality of pixels included in the image frame. Specifically, the representative color determination unit 120 may classify representative colors according to the following Equation (5) according to the calculated color value (H). Meanwhile, the representative color may be one of Red, Yellow, Green, Cyan, Blue, and Magenta according to one embodiment of the present invention. However, as described above, the representative color may be six, but it is only one embodiment, and the representative color may be set to three to twelve according to the performance of the electronic device 100. [

At this time, Th may be a value between 0 and 30.

The representative color determining unit 120 calculates brightness values for a plurality of pixels included in the input image frame using the R, G, and B values and weight values as shown in Equation (6) As shown in FIG.

At this time, Th may be a value between 0 and 30.

The input dynamic range calculator 130 calculates an input dynamic range for a plurality of representative colors based on the brightness information of the input image frame.

Specifically, the input dynamic range calculator 130 may analyze the input image frame and determine a maximum brightness value and a minimum brightness value of representative colors included in the input image frame. At this time, the input dynamic range calculating unit 130 can obtain the maximum brightness value and the minimum brightness value for each representative color by the following Equation (8).

The input dynamic range calculator 130 may determine the minimum value among the minimum brightness values for the representative colors as the minimum brightness value Y_f_min of the image frame, as shown in Equation (9) below.

The input dynamic range calculator 130 determines the minimum brightness value of the image frame as a minimum value of the representative colors as shown in Equation (10) below, and sets the maximum brightness value of each representative color included in the image frame to the representative color The input dynamic range for a plurality of representative colors can be determined.

For example, the input dynamic range calculator 130 may calculate the input dynamic range 210-1 for the neutral color, the input dynamic range 210-2 for the red color, An input dynamic range 210-3 for yellow, an input dynamic range 210-4 for green, an input dynamic range 210-5 for cyan (Cyan), a blue (Blue) The input dynamic range 210-6 and the input dynamic range 210-7 for magenta can be calculated.

The dynamic range expanding unit 140 expands the dynamic range for each representative color based on at least one of the brightness information of the input image frame and the display characteristics of the electronic device.

First, the dynamic range extension unit 140 can calculate the maximum gain value for each representative color by using the ratio of the maximum brightness value of representative colors included in the image frame to the maximum brightness value for each representative color.

Specifically, the full dynamic range of each representative color is a maximum brightness value for each representative color. In this case, when the maximum value of the pixel is expressed by 1, the full dynamic range per representative color is red (1,0,0), yellow (1,1,0), green (0,1,0) (0, 1, 1), blue (0, 0, 1), and magenta are defined as (1, 0, 1) and are represented by Y_R_Full, Y_Y_Full, Y_G_Full, Y_C_Full, Y_B_Full, Y_M_Full, Y_N_Full . The dynamic range expansion unit 140 calculates the first-order maximum gain value Gain_max through Equation (11) below so that the dynamic range expansion can be extended to the dynamic range that can be expressed to the maximum with respect to the input dynamic range .

At this time, the dynamic range extending unit 140 may determine a weight for each representative color based on color characteristics and user preferences that the electronic device 100 can output. The dynamic range extension unit 140 may calculate a final gain value for each representative color by applying a weight to the calculated maximum gain value as in Equation (12).

The values of weight_R, weight_Y, weight_G, weight_C, weight_B, weight_M, and weight_N of representative colors may be set to one of values between 0 and 1 according to color characteristics and user preferences that can be output by the electronic device 100 have.

The dynamic range extending unit 140 may extend the dynamic range for each representative color by applying a final gain value to the input dynamic range for each representative color. Specifically, the dynamic range expansion unit 140 multiplies the input dynamic range for each representative color by the final gain value for each representative color to obtain an output dynamic range 220-1 for a neutral color, The output dynamic range 220-2 for red, the output dynamic range 220-3 for yellow, the output dynamic range 220-4 for green, and cyan The output dynamic range 220-6 for the output dynamic range 220-5, the output dynamic range 220-6 for the blue (Blue), and the output dynamic range 220-7 for the magenta (Magenta) can be calculated.

On the other hand, when the final gain value of a specific representative color differs from the final gain value of another representative color, only a specific gamut may be greatly enlarged, resulting in an unnatural result. Accordingly, the dynamic range extending unit 140 can restrictively adjust the gain value for the representative color as shown in Equation (13) by referring to the final gain value of the adjacent representative color.

In addition, the dynamic range extending unit 140 may calculate the gain value between the representative colors by interpolating the gain values with respect to the representative color. 3, when the gain for each representative color is calculated, the dynamic range expanding unit 140 interpolates and calculates the gain value HGx between the representative colors as shown in the following equation (14) can do.

At this time, HGx is Gain_R for Hue = 0.

The gamut enhancement gain value for additional brightness is given by Weight_gamut, and Weight_gamut can be [1.0 ~ Hue_gain].

When the dynamic range expansion gain for each representative color is given, the dynamic range expanding unit 140 may calculate the dynamic range by using the following mathematical expression in consideration of at least one of the complexity and the color model of the electronic device 100: Can be determined as one of the equations (15) to (17).

The dynamic range extension unit 140 performs 3D interpolation as shown in FIG. Specifically, the dynamic range expansion unit 140 maps the target points by using a tetrahedral interpolation method on the coordinates of representative colors, thereby interpolating the interim values. FIG. 4 is a diagram illustrating an input value and an output value when 3D interpolation is performed, and FIG. 5 is a diagram showing an actual input value and an actual output value when a gain value is determined for each representative color.

The output unit 150 outputs the image frame whose brightness is adjusted based on the extended dynamic range. At this time, the output unit 150 may perform a display processing operation to display an image frame whose brightness is adjusted, and may perform a print processing operation to print an image frame whose brightness is adjusted.

As described above, it is possible to provide a clearer image quality to a user by expanding the dynamic range by color in consideration of the information on the input image and the color expression range of the electronic device 100. In addition, there is an effect of improving the phenomenon of being shifted to the surrounding color without being extended at the gamut boundary.

FIGS. 7 and 8 are views showing the result of processing image frames by the conventional and dynamic range extending method of the present invention. As shown in FIG. 7, when a black or white component is included in the input image frame, there is a disadvantage that the image quality of the output image frame can not be improved because the dynamic expansion is difficult. However, by extending the dynamic range for each representative color as in the embodiment of the present invention, even if black or white components are included in the input image frame, as shown in FIG. 8, It can be confirmed that it is improved.

Hereinafter, a method of controlling an electronic device for extending a dynamic range according to an embodiment of the present invention will be described with reference to FIG.

First, the electronic device 100 analyzes the input image frame to determine a representative color of a plurality of pixels constituting the image frame (S910). Specifically, the electronic device 100 determines at least one of a hue value and a saturation value for a plurality of pixels, and determines whether a plurality of pixels are chromatic or achromatic based on at least one of a hue value and a saturation value , It is possible to determine each representative color for pixels determined as chromatic colors among the plurality of pixels.

Then, the electronic device 100 calculates an input dynamic range for a plurality of representative colors based on the brightness information of the input image frame (S920). Specifically, the electronic device 100 analyzes the input image frame, determines a maximum brightness value and a minimum brightness value for each of the representative colors included in the input image frame, and determines the minimum brightness value The minimum value of the image frame is determined as the minimum brightness value of the image frame, the minimum brightness value of the image frame is determined as the minimum value of the representative colors, the maximum brightness value of each representative color included in the image frame is determined as the maximum value of the representative colors, The input dynamic range of the representative color can be calculated.

In addition, the electronic device 100 may expand the dynamic range for each representative color based on at least one of the brightness information of the input image frame and the display characteristics of the electronic device (S930). Specifically, the electronic device 100 can calculate the maximum gain value for each representative color by using the ratio of the maximum brightness value of representative colors included in the image frame to the maximum brightness value for each representative color. The electronic device 100 determines weights for representative colors based on color characteristics and user preferences that can be output by the electronic device 100 and applies a weight to the calculated maximum gain values to obtain a final gain value , And the dynamic range can be extended for each representative color by applying a final gain value to the input dynamic range.

Then, the electronic device 100 outputs the image frame whose brightness is adjusted based on the extended dynamic range (S940).

As described above, by extending the dynamic range for each representative color, the electronic device 100 can provide a clearer image quality to the user

Meanwhile, in the above-described embodiment, the dynamic range is expanded for all the pixels included in the input image frame. However, the dynamic range may be expanded only for one embodiment, have. Specifically, as shown in FIG. 10, the electronic device 100 may further include an area selection unit 160 to select an area of the input image frame to which the dynamic range is to be extended. At this time, the area selecting unit 160 can select the remaining area excluding the text area and the blank area.

An apparatus according to the present embodiments may include a processor, a memory for storing and executing program data, a permanent storage such as a disk drive, a communication port for communicating with an external device, a touch panel, a key, User interface devices, and the like. Methods implemented with software modules or algorithms may be stored on a computer readable recording medium as computer readable codes or program instructions executable on the processor. Here, the computer-readable recording medium may be a magnetic storage medium such as a read-only memory (ROM), a random-access memory (RAM), a floppy disk, a hard disk, ), And a DVD (Digital Versatile Disc). The computer-readable recording medium may be distributed over networked computer systems so that computer readable code can be stored and executed in a distributed manner. The medium is readable by a computer, stored in a memory, and executable on a processor.

This embodiment may be represented by functional block configurations and various processing steps. These functional blocks may be implemented in a wide variety of hardware and / or software configurations that perform particular functions. For example, embodiments may include integrated circuit components such as memory, processing, logic, look-up tables, etc., that may perform various functions by control of one or more microprocessors or other control devices Can be employed. Similar to how components may be implemented with software programming or software components, the present embodiments may be implemented in a variety of ways, including C, C ++, Java (" Java), an assembler, and the like. Functional aspects may be implemented with algorithms running on one or more processors. In addition, the present embodiment can employ conventional techniques for electronic environment setting, signal processing, and / or data processing. Terms such as "mechanism", "element", "means", "configuration" are broadly used and are not limited to mechanical and physical configurations. The term refers to a set of routines ). ≪ / RTI >

The specific implementations described in this embodiment are illustrative and do not in any way limit the scope of the invention. For brevity of description, descriptions of conventional electronic configurations, control systems, software, and other functional aspects of such systems may be omitted. Also, the connections or connecting members of the lines between the components shown in the figures are illustrative of functional connections and / or physical or circuit connections, which may be replaced or additionally provided by a variety of functional connections, physical Connection, or circuit connections.

In this specification (particularly in the claims), the use of the term "above " and similar indication words may refer to both singular and plural. In addition, when a range is described, it includes the individual values belonging to the above range (unless there is a description to the contrary), and the individual values constituting the above range are described in the detailed description. Finally, if there is no explicit description or contradiction to the steps constituting the method, the steps may be performed in an appropriate order. It is not necessarily limited to the description order of the above steps. The use of all examples or exemplary terms (e. G., The like) is merely intended to be illustrative of technical ideas and is not to be limited in scope by the examples or the illustrative terminology, except as by the appended claims. It will also be appreciated by those skilled in the art that various modifications, combinations, and alterations may be made depending on design criteria and factors within the scope of the appended claims or equivalents thereof.

110: input unit 120: representative color determination unit
130: Dynamic Range Extension Unit 140: Gain Value Calculation Unit
150: output unit 160:

Claims (18)

A method of controlling an electronic device,
Analyzing an input image frame to determine a representative color of a plurality of pixels constituting the image frame;
Calculating an input dynamic range for a plurality of representative colors based on the brightness information of the input image frame;
Expanding a dynamic range for each representative color based on at least one of brightness information of the input image frame and display characteristics of the electronic device; And
And outputting an image frame whose brightness is adjusted based on the extended dynamic range. The method according to claim 1,
The method of claim 1,
Determining at least one of a hue value and a saturation value for the plurality of pixels;
Determining whether the plurality of pixels are chromatic or achromatic based on at least one of the hue and saturation values;
And determining a representative color of each of the pixels determined to be chromatic color among the plurality of pixels. 3. The method of claim 2,
The step of determining whether the color is chromatic color or colorless color includes:
Wherein the pixel determining unit determines that the pixel whose color value is not defined or whose saturation value is less than or equal to a predetermined value is an achromatic color and that the pixel whose saturation value exceeds a predetermined value is a chromatic color. The method according to claim 1,
Wherein the step of calculating the input dynamic range comprises:
Analyzing the input image frame to determine a maximum brightness value and a minimum brightness value of representative colors included in the input image frame;
Determining a minimum value among the minimum brightness values for the representative colors as a minimum brightness value of the image frame;
Determining a minimum brightness value of the image frame as a minimum value of the representative colors and determining a maximum brightness value of each of the representative colors included in the image frame as a maximum value of the representative colors to determine an input dynamic range of the plurality of representative colors, And a control step of controlling the control method. The method according to claim 1,
Wherein expanding the dynamic range comprises:
And calculating a maximum gain value for each representative color by using a ratio of a maximum brightness value that can be output maximum for each representative color and a maximum brightness value of each representative color included in the image frame. 6. The method of claim 5,
Wherein expanding the dynamic range comprises:
Determining a weight for each representative color based on color characteristics and user preferences that the electronic device can output;
Calculating a final gain value for each representative color by applying a weight to the calculated maximum gain value; And
And extending the dynamic range by the representative color by applying the final gain value to the input dynamic range for each representative color. The method according to claim 6,
The step of determining the weight includes:
Wherein a weight is determined for each of the representative colors by considering a maximum gain value of adjacent representative colors. The method according to claim 1,
Wherein expanding the dynamic range comprises:
And interpolating gain values for the representative color to calculate a gain value between the representative colors. The method according to claim 1,
And selecting an area for expanding a dynamic range of the input image frame,
Wherein the determining of the representative color of the plurality of pixels comprises:
Wherein a representative color of a plurality of pixels included in the selected region is determined. In an electronic device,
An input unit for receiving an image frame;
A representative color determining unit for analyzing the input image frame to determine a representative color of a plurality of pixels constituting the image frame;
An input dynamic range calculation unit for calculating an input dynamic range for a plurality of representative colors based on the brightness information of the input image frame;
A dynamic range extension unit for expanding the dynamic range by the representative color based on at least one of the brightness information of the input image frame and the display characteristic of the electronic device; And
And an output unit for outputting an image frame whose brightness is adjusted based on the extended dynamic range. 11. The method of claim 10,
The representative color determining unit may determine,
Determining at least one of a hue value and a saturation value for the plurality of pixels, determining whether the plurality of pixels are chromatic or achromatic based on at least one of the hue value and the saturation value, And determines the representative color of each of the pixels judged to be among the chromatic colors. 12. The method of claim 11,
The representative color determining unit may determine,
The pixel determining unit determines that the pixel whose color value is not defined or whose saturation value is less than or equal to a preset value is an achromatic color and that the pixel whose saturation value exceeds a predetermined value is a chromatic color. 11. The method of claim 10,
Wherein the input dynamic range calculating section
Wherein the controller determines the maximum brightness value and the minimum brightness value of each representative color included in the input image frame by analyzing the input image frame, Determining the minimum brightness value of the image frame as the minimum brightness value, determining the minimum brightness value of the image frame as the minimum value of the representative colors, determining the maximum brightness value of each of the representative colors included in the image frame as the maximum value of the representative colors, And the input dynamic range of the representative color is calculated. 11. The method of claim 10,
The dynamic range expansion unit may include:
Wherein the maximum gain value for each representative color is calculated using a ratio of a maximum brightness value that can be output maximum for each representative color and a maximum brightness value of each representative color included in the image frame. 15. The method of claim 14,
The dynamic range expansion unit may include:
Wherein the electronic device determines a weight for each representative color based on color characteristics and user preferences that can be output by the electronic device, calculates a final gain value for each representative color by applying a weight to the calculated maximum gain value, And applies the final gain value to the range to extend the dynamic range by the representative color. 16. The method of claim 15,
The dynamic range expansion unit may include:
Wherein the weights are determined for each of the representative colors in consideration of a maximum gain value of adjacent representative colors. 11. The method of claim 10,
The dynamic range expansion unit may include:
And calculates a gain value between the representative colors by interpolating gain values for the representative color. 11. The method of claim 10,
And an area selector for selecting an area for expanding the dynamic range of the input image frame,
The representative color determining unit may determine,
And determines a representative color of a plurality of pixels included in the selected region.

Images