KR102160247B1 - Electronic apparatus and Method for controlling the electronic apparatus thereof - Google Patents

Abstract

An electronic device for extending a dynamic range and a control method thereof are provided. The control method of the electronic device analyzes an input image frame to determine representative colors of a plurality of pixels constituting an image frame, and calculates an input dynamic range for a plurality of representative colors based on the brightness information of the input image frame. The dynamic range is extended by calculating a gain value corresponding to the representative color based on at least one of the brightness information of the input image frame and the display characteristics of the electronic device, and the brightness is adjusted based on the extended dynamic range. Prints.

Description

TECHNICAL FIELD [0001] Electronic apparatus and method for controlling the electronic apparatus thereof

The present invention relates to an electronic device and a control method thereof, and to an electronic device and a control method thereof for extending a dynamic range based on a color distribution of an input image frame and a gamut expression range of an output device.

In accordance with the needs of users who require clear image quality, modern electronic devices expand the dynamic range when outputting images. Existing electronic devices extend the dynamic range by adjusting the maximum and minimum ranges of the histogram according to the brightness information of the image. Specifically, conventional electronic devices analyze the input image, generate a histogram based on the analysis result, explain the extended range of the dynamic range according to the brightness information, and expand the histogram based on the extended range of the dynamic range. , It provided clearer picture quality to users.

That is, in the related art, the dynamic range is extended by determining the minimum and maximum values of the histogram according to the brightness information of the image. However, when a letter box or text including black or white components is present 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 case of an 8-bit system). Accordingly, it is difficult to substantially expand the dynamic range, resulting in a problem that the improvement in image quality is not large.

The present invention was conceived to solve the above-described problem, and an object of the present invention is to provide a clearer image quality to the user by expanding the dynamic range for each color in consideration of the input image information and the color expression range of the electronic device. It is to provide a capable electronic device and a control method thereof.

According to an embodiment of the present invention for achieving the above object, a method for controlling an electronic device includes: analyzing an input image frame and determining representative colors of a plurality of pixels constituting the image frame; Calculating input dynamic ranges for a plurality of representative colors based on brightness information of the input image frame; Expanding a dynamic range for each of the representative colors based on at least one of brightness information of the input image frame and a display characteristic of the electronic device; And outputting an image frame whose brightness is adjusted based on the extended dynamic range.

In addition, the determining of the representative color may include determining at least one of a color 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 saturation value; And determining a representative color of each of the pixels determined to be a chromatic color among the plurality of pixels.

In addition, the step of determining whether the chromatic color is a colorless color is determined that a pixel whose color value is not defined or whose saturation value is less than or equal to a preset value is determined as an achromatic color, and a pixel whose saturation value exceeds a preset value is called a chromatic color I can judge.

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

In addition, in the expanding of the dynamic range, the maximum gain value for each representative color is calculated using a ratio of a maximum output brightness value for each representative color and a maximum brightness value for each of the representative colors included in the image frame. It may include;

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

In addition, in determining the weight, the weight for each representative color may be determined in consideration of a maximum gain value of an adjacent representative color.

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

In addition, selecting a region for extending the dynamic range among the input image frames; further comprising, determining a representative color of the plurality of pixels, the representative color of a plurality of pixels included in the selected region Can be judged.

Meanwhile, according to an embodiment of the present invention for achieving the above object, an electronic device includes: an input unit for receiving an image frame; A representative color determination unit that analyzes the input image frame and determines representative colors of a plurality of pixels constituting the image frame; An input dynamic range calculator configured to calculate an input dynamic range for a plurality of representative colors based on brightness information of the input image frame; A dynamic range expansion unit extending a dynamic range for each of the representative colors based on at least one of brightness information of the input image frame and a 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 determination unit determines at least one of a color value and a saturation value for the plurality of pixels, and determines whether the plurality of pixels are chromatic or achromatic based on at least one of the color value and saturation value. It is determined, and a representative color of each of the pixels determined to be a chromatic color among the plurality of pixels may be determined.

In addition, the representative color determination unit may determine that a 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 may determine that a pixel whose saturation value exceeds a preset value is a chromatic color.

In addition, the input dynamic range calculator analyzes the input image frame to determine a maximum brightness value and a minimum brightness value for each of the representative colors included in the input image frame, and the minimum brightness value for the representative colors The minimum value among the values 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, and the maximum brightness value of each of the representative colors included in the image frame is the representative color. It is possible to calculate the input dynamic ranges of the plurality of representative colors by determining the maximum value of each.

In addition, the dynamic range extension unit may calculate a maximum gain value for each representative color using a ratio of a maximum output brightness value for each representative color and a maximum brightness value for each of the representative colors included in the image frame. .

In addition, the dynamic range extension unit determines a weight for each representative color based on color characteristics and user preferences that can be output by the electronic device, and applies a weight to the calculated maximum gain value to obtain a final gain for each representative color. A value is calculated and the final gain value is applied to the input dynamic range to extend the dynamic range for each of the representative colors.

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

In addition, the dynamic range extension unit may calculate a gain value between the representative colors by interpolating gain values for the representative colors.

In addition, a region selector for selecting a region for extending a dynamic range among the input image frames, the representative color determination unit may determine representative colors of a plurality of pixels included in the selected region. .

As in the various embodiments of the present invention as described above, by expanding the dynamic range for each color in consideration of the information on the input image and the color expression range of the electronic device, it is possible to provide more vivid image quality to the user. In addition, there is an effect of improving the phenomenon of not expanding at the gamut boundary and moving to the surrounding color.

1 is a block diagram showing a configuration of an electronic device according to an embodiment of the present invention;
2A and 2B are graphs for explaining input brightness distribution and output brightness distribution for each representative color according to an embodiment of the present invention;
3 is a view 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;
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 extension method;
8 is a diagram for comparing an input image and an output image according to the range extension method of the present invention;
9 is a flowchart illustrating a method for extending a dynamic range for each representative color according to an embodiment of the present invention;
10 is a block diagram illustrating a configuration of an electronic device according to another embodiment of the present invention.

Since these embodiments can apply various transformations and have various embodiments, specific embodiments will be illustrated in the drawings and described in detail in the detailed description. However, this is not intended to limit the scope of the specific embodiment, it is to be understood to include all conversions, equivalents, or substitutes included in the disclosed spirit and technical scope. In describing the embodiments, when it is determined that a detailed description of a related known technology may obscure the subject matter, the detailed description thereof will be omitted.

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

The terms used in the present application are used only to describe specific embodiments, and are not intended to limit the scope of the rights. Singular expressions include plural expressions unless the context clearly indicates otherwise. In the present application, terms such as "comprise" or "comprise" are intended to designate the existence of features, numbers, steps, actions, components, parts, or a combination thereof described in the specification, but one or more other It is to be understood that the presence or addition of features, numbers, steps, actions, components, parts, or combinations thereof, does not preclude in advance the possibility of being excluded.

In an embodiment, the'module' or'unit' performs at least one function or operation, and may be implemented as hardware or software, or a combination of hardware and software. In addition, a plurality of'modules' or a plurality of'units' are integrated into at least one module except for'modules' or'units' that need to be implemented with specific hardware and implemented as at least one processor (not shown). Can be.

Hereinafter, embodiments will be described in detail with reference to the accompanying drawings, and in the description with reference to the accompanying drawings, the same or corresponding constituent elements are assigned the same reference numerals, and redundant descriptions thereof will be omitted.

1 is a block diagram showing a configuration of an electronic device 100 according to an embodiment of the present invention. As shown in FIG. 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. In this case, the electronic device 100 may be implemented as various devices such as a digital TV, a desktop PC, a notebook PC, a tablet PC, a smart phone, a kiosk, and a printing device capable of outputting an image frame.

The input unit 110 receives an image frame. In this case, the input image frame may be expressed as one of an RGB model, a YCbCr model, and an HSV model.

At this time, the RGB model is the most notable color model, and expresses color as a combination of three components of red, green, and blue. In the RGB model, black is R=G=B=0, white is R=G=B=255, red is R=255, G=B=0, yellow is R=G=255, B=0. do. In the case of R=G=B, gray color is achromatic. Since each of R, G, and B can have values between 0 and 255, a total of 256*256*256 = 16,777,216 colors can be expressed using the RGB color model.

The YCbCr model is a color model that separates and expresses the brightness component (Y) and color difference information (Cb, Cr) from RGB colors. In the YCbCr model, Y, Cb, and Cr each have a value between 0 and 255, and as Y increases, the overall brightens, and as Y decreases, the overall darkens. The YCbCr model is a color model used in MPEG. Taking advantage of the fact that the human eye is sensitive to the difference in brightness but is relatively insensitive to the difference in color, a large number of bits (resolution) is assigned to Y, and a lower number of bits is assigned to Cb and Cr. Compress the video in an allotted way. Therefore, when processing video data, using the YCbCr model has the advantage of not requiring separate color conversion. The YCbCr model is also called the YUV model.

The HSV model expresses color in three components: Hue (hue), saturation (saturation), and value (brightness). Hue indicates what color system a color is (e.g. red, blue, ., etc.), Saturation indicates how vivid (pure) the color is, and Value Represents the intensity of the color. In the case of the HSV model, each of H, S, and V is expressed as a value between 0 and 255. Since the H value represents the type of color, the size is meaningless and represents a simple index. If the S value is 0, the color is achromatic (gray), and if it is 255, the color is the brightest (pure). The smaller the value of V, the darker it is, and the larger the value is, the brighter the color. The HSV color model has a conic shape and a cylindrical shape as shown in the figure.

The representative color determination unit 120 analyzes the input image frame and determines 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 color value H and a chroma value for a plurality of pixels included in the input image frame. In this case, the representative color determination unit 120 selects one of Equations 1 to 4 below according to the complexity tolerance of the electronic device 100 and selects a color value H for a plurality of pixels and At least one of the chroma values may be determined.

At this time, the Cb and Cr values may be the same as those defined in BT 601 or BT 709. For example, in the case of 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 BT 709 formula , Cb is -0.1687*R -0.3313*G + 0.5*B, and Cr is 0.5*R -0.4187*G-0.0813*B.

At this time, α is (2*R-G-B)/2, and β is sqrt(3)/2 *(G-B).

In addition, the representative color determination unit 120 may determine whether a plurality of pixels are chromatic or neutral based on the color value H and the chroma value. Specifically, the representative color determination unit 120 determines that a pixel whose color value H is not defined (that is, when R=G=B) or whose saturation value is less than a preset value is an achromatic color, and the saturation value is Pixels greater than or equal to the set value may be determined as chromatic colors.

In addition, the representative color determination unit 120 may determine a representative color for pixels determined to be a reproducible color among a plurality of pixels included in the image frame. Specifically, the representative color determination unit 120 may classify the representative color according to Equation 5 below according to the calculated color value H. Meanwhile, a representative color according to an embodiment of the present invention may be one of red, yellow, green, cyan, blue, and magenta. However, as described above, the number of representative colors may be 6, but this is only an embodiment, and the number of representative colors may be set to 3 to 12 according to the performance of the electronic device 100.

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

In addition, the representative color determination unit 120 calculates brightness values for a plurality of pixels included in the input image frame using R, G, B values and weights as shown in Equation 6, and Equation 7 As shown, it can be stored for each achromatic color and a representative color.

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

The input dynamic range calculation unit 130 calculates input dynamic ranges 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 an input image frame and determine a maximum brightness value and a minimum brightness value for each of the representative colors included in the input image frame. In this case, the input dynamic range calculation unit 130 may obtain a maximum brightness value and a minimum brightness value for each representative color by Equation 8 below.

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

In addition, the input dynamic range calculation unit 130 determines the minimum brightness value of the image frame as the minimum value of the representative colors as shown in Equation 10 below, and determines the maximum brightness value of each of the representative colors included in the image frame as the representative color. It is possible to determine the input dynamic range for a plurality of representative colors by determining the maximum value of.

For example, as shown in FIG. 2A, the input dynamic range calculation unit 130 includes an input dynamic range 210-1 for a neutral color and an input dynamic range 210-2 for red. ), input dynamic range for Yellow (210-3), input dynamic range for Green (210-4), input dynamic range for Cyan (210-5), and Blue The input dynamic range 210-6 for) and the input dynamic range 210-7 for magenta may be calculated.

The dynamic range extension unit 140 extends a dynamic range for each representative color based on at least one of brightness information of an input image frame and display characteristics of an electronic device.

First, the dynamic range extension unit 140 may calculate a maximum gain value for each representative color using a ratio of a maximum output brightness value for each representative color and a maximum brightness value for each of the representative colors included in the image frame.

Specifically, the full dynamic range for each representative color is a brightness value that can be expressed to the maximum for each representative color. In this case, when the maximum value of the pixel is expressed as 1, the full dynamic range for each representative color is (1,0,0) for red, (1,1,0) for yellow, (0,1,0) for green, Cyan is set to (0,1,1), blue is set to (0,0,1), magenta is set to (1,0,1), respectively. I can. And, the dynamic range expansion unit 140 maintains the color balance to the maximum expressible dynamic range with respect to the input dynamic range, and calculates the first maximum gain value (Gain_max) through Equation 11 below. I can.

In this case, the dynamic range extension unit 140 may determine a weight for each representative color based on color characteristics and user preferences that can be output by the electronic device 100. In addition, 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 shown in Equation 12.

At this time, the weight_R, weight_Y, weight_G, weight_C, weight_B, weight_M, and weight_N values, which are weights for each representative color, may be set to one of values between 0 and 1 according to color characteristics that can be output by the electronic device 100 and user preference have.

In addition, the dynamic range extension unit 140 may apply a final gain value to the input dynamic range for each representative color to extend the dynamic range for each representative color. Specifically, the dynamic range extension unit 140 multiplies the input dynamic range for each representative color by the final gain value for each representative color, and as shown in FIG. 2B, the output dynamic range 220-1 for a neutral color, Output dynamic range for Red (220-2), Output dynamic range for Yellow (220-3), Output dynamic range for Green (220-4), Cyan An output dynamic range 220-5 for blue, an output dynamic range 220-6 for blue, and an output dynamic range 220-7 for magenta may be calculated.

On the other hand, when the final gain value of a specific representative color is much different from the final gain value of other representative colors, only a specific color gamut may be greatly expanded, resulting in unnatural results. Accordingly, the dynamic range extension unit 140 may restrictively adjust the gain value for each representative color as shown in Equation 13 by referring to the final gain value of the adjacent representative color.

Also, the dynamic range extension unit 140 may calculate a gain value between representative colors by interpolating gain values for the representative colors. Specifically, as shown in FIG. 3, when the gain for each representative color is calculated, the dynamic range expansion unit 140 interpolates the gain value HGx between representative colors as shown in Equation 14 below. can do.

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

The gamut expansion gain value for the additionally brightened brightness is given by Weight_gamut, and Weight_gamut can have [1.0 ~ Hue_gain].

In addition, when the dynamic range expansion gain for each representative color is given, the dynamic range expansion unit 140 includes the following math in consideration of at least one of the complexity and color model of the electronic device 100. It may be determined by one of Equations 15 to 17.

The dynamic range extension unit 140 performs 3D interpolation, as shown in FIG. 6. Specifically, the dynamic range extension unit 140 maps target points using a tetrahedral interpolation method with respect to coordinates of a representative color to interpolate between values. FIG. 4 is a diagram illustrating input values and output values when 3D interpolation is performed, and FIG. 5 is a diagram illustrating actual input values and actual output values when gain values are determined for each representative color.

The output unit 150 outputs an image frame whose brightness is adjusted based on the extended dynamic range. In this case, 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, by expanding the dynamic range for each color in consideration of the information on the input image and the color expression range of the electronic device 100, it is possible to provide more vivid image quality to the user. In addition, there is an effect of improving the phenomenon of not expanding at the gamut boundary and moving to the surrounding color.

7 and 8 are diagrams showing a result of processing an image frame according to the conventional and dynamic range extension method of the present invention. As shown in FIG. 7, when a large number of black or white components are included in an input image frame, there is a disadvantage in that the improvement in quality of the output image frame is not large because it is difficult to substantially expand dynamics. However, by expanding the dynamic range for each representative color as in the exemplary embodiment of the present invention, as shown in FIG. 8, even if a large number of black or white components are included in the input image frame, the quality improvement of the output image frame is higher than that of the prior art. It can be seen 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. 9.

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

Further, 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 to determine a maximum brightness value and a minimum brightness value for each of the representative colors included in the input image frame, and among the minimum brightness values for the representative colors The minimum value 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, and the maximum brightness value of each of the representative colors 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.

Further, the electronic device 100 may extend the 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 (S930). Specifically, the electronic device 100 may calculate a maximum gain value for each representative color by using a ratio of a maximum output brightness value for each representative color and a maximum brightness value for each of the representative colors included in the image frame. Further, the electronic device 100 determines a weight for each representative color based on color characteristics and user preferences that can be output by the electronic device 100, and applies the weight to the calculated maximum gain value to obtain a final gain value for each representative color. Is calculated and the final gain value is applied to the input dynamic range to extend the dynamic range for each representative color.

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

As described above, by expanding the dynamic range for each representative color, the electronic device 100 can provide more vivid image quality to the user.

Meanwhile, in the above-described embodiment, it has been described that the dynamic range is extended for all pixels included in the input image frame, but this is only an embodiment, and the dynamic range of the pixels for some areas of the image frame can be extended. have. Specifically, as illustrated in FIG. 10, the electronic device 100 may further include a region selector 160 to select a region in which the dynamic range is to be expanded among input image frames. In this case, the region selector 160 may select the remaining regions excluding the text region or the blank region.

The device according to the present embodiments includes 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, a button, etc. It may include a user interface device and the like. Methods implemented as 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, as a computer-readable recording medium, a magnetic storage medium (e.g., read-only memory (ROM), random-access memory (RAM), floppy disk, hard disk, etc.) and optical reading medium (e.g., CD-ROM ) And DVD (Digital Versatile Disc). The computer-readable recording medium is distributed over network-connected computer systems, so that computer-readable codes can be stored and executed in a distributed manner. The medium is readable by a computer, stored in memory, and executed on a processor.

This embodiment may be represented by functional block configurations and various processing steps. These functional blocks may be implemented with various numbers of hardware or/and software configurations that perform specific functions. For example, the embodiment is an integrated circuit configuration such as memory, processing, logic, a look-up table, etc., capable of executing various functions by controlling one or more microprocessors or other control devices Can be hired. Similar to how components can be implemented with software programming or software elements, this embodiment includes various algorithms implemented with a combination of data structures, processes, routines or other programming components, including C, C++, Java ( Java), an assembler, or the like may be implemented in a programming or scripting language. Functional aspects can be implemented with an algorithm running on one or more processors. In addition, the present embodiment may employ a conventional technique for electronic environment setting, signal processing, and/or data processing. Terms such as “mechanism”, “element”, “means”, and “configuration” can be used broadly, and are not limited to mechanical and physical configurations. Can include the meaning of ).

The specific implementations described in the present embodiment are examples, and do not limit the technical scope in any way. For brevity of the specification, descriptions of conventional electronic configurations, control systems, software, and other functional aspects of the systems may be omitted. In addition, the connection or connection members of the lines between the components shown in the drawings exemplarily represent functional connections and/or physical or circuit connections, and in an actual device, various functional connections that can be replaced or additionally Connections, or circuit connections, may be represented.

In the present specification (especially the claims), the use of the term "above" and a reference term similar thereto may correspond to both the singular and the plural. In addition, when a range is described, it includes individual values belonging to the above range (unless otherwise stated), it is the same as describing each individual value constituting the range in the detailed description. Finally, if there is no explicit order or contrary to the steps constituting the method, the steps may be performed in an appropriate order. It is not necessarily limited to the order of description of the steps. The use of all examples or illustrative terms (for example, etc.) is merely for describing the technical idea in detail, and the scope is not limited due to the examples or illustrative terms unless limited by the claims. In addition, those skilled in the art can recognize that various modifications, combinations, and changes may be configured according to design conditions and factors within the scope of the appended claims or their equivalents.

110: input unit 120: representative color determination unit
130: dynamic range expansion unit 140: gain value calculation unit
150: output unit 160: selection unit

Claims (18)

In the control method of an electronic device,
Analyzing an input image frame to determine representative colors of a plurality of pixels constituting the image frame;
Calculating input dynamic ranges for a plurality of representative colors based on brightness information of the input image frame;
Expanding a dynamic range for each representative color based on brightness information of the input image frame and a display characteristic of the electronic device; And
And outputting an image frame whose brightness is adjusted based on the extended dynamic range. The method of claim 1,
The step of determining the representative color,
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 saturation value;
And determining a representative color of each of the pixels determined to be a chromatic color among the plurality of pixels. The method of claim 2,
The step of determining whether the chromatic color or colorless color is,
And determining a pixel whose color value is not defined or whose saturation value is less than or equal to a preset value as an achromatic color, and determining a pixel whose saturation value exceeds a preset value as a chromatic color. The method of claim 1,
The step of calculating the input dynamic range,
Analyzing the input image frame and determining a maximum brightness value and a minimum brightness value for each of the representative colors included in the input image frame;
Determining a minimum value among minimum brightness values for the representative colors 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, and the maximum brightness value of each of the representative colors included in the image frame is determined as the maximum value of the representative colors to determine the input dynamic range of the plurality of representative colors. Control method comprising; calculating. The method of claim 1,
The step of expanding the dynamic range,
And calculating a maximum gain value for each of the representative colors using a ratio of the maximum outputable brightness value for each of the representative colors and a maximum brightness value of each of the representative colors included in the image frame. The method of claim 5,
The step of expanding the dynamic range,
Determining a weight for each representative color based on a color characteristic and a user preference that can be output by the electronic device;
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 for each representative color by applying the final gain value to the input dynamic range for each representative color. The method of claim 6,
The step of determining the weight,
And determining a weight for each of the representative colors in consideration of a maximum gain value of an adjacent representative color. The method of claim 1,
The step of expanding the dynamic range,
Computing a gain value between the representative colors by interpolating the gain values for the representative color; the control method further comprising. The method of claim 1,
Selecting a region for extending a dynamic range among the input image frames; further comprising,
Determining the representative color of the plurality of pixels,
And determining representative colors of a plurality of pixels included in the selected area. In the electronic device,
An input unit for receiving an image frame;
A representative color determination unit that analyzes the input image frame and determines representative colors of a plurality of pixels constituting the image frame;
An input dynamic range calculator configured to calculate an input dynamic range for a plurality of representative colors based on brightness information of the input image frame;
A dynamic range extension unit that expands a dynamic range for each of the representative colors based on brightness information of the input image frame and display characteristics of the electronic device; And
And an output unit for outputting an image frame whose brightness is adjusted based on the extended dynamic range. The method of claim 10,
The representative color determination unit,
Determine at least one of a color value and a saturation value for the plurality of pixels, determine whether the plurality of pixels are chromatic or achromatic based on at least one of the color value and saturation value, and the plurality of pixels An electronic device comprising determining a representative color of each of the pixels determined to be a chromatic color. The method of claim 11,
The representative color determination unit,
And determining a pixel whose color value is not defined or whose saturation value is less than or equal to a preset value as achromatic color, and determines a pixel whose saturation value exceeds a preset value as a chromatic color. The method of claim 10,
The input dynamic range calculation unit,
The input image frame is analyzed to determine a maximum brightness value and a minimum brightness value for each of the representative colors included in the input image frame, and a minimum value among the minimum brightness values for the representative colors is determined for the image frame. It is determined as a minimum brightness value, the minimum brightness value of the image frame is determined as the minimum value of the representative colors, the maximum brightness value of each of the representative colors included in the image frame is determined as the maximum value of the representative colors, and the plurality of An electronic device, characterized in that calculating an input dynamic range of a representative color. The method of claim 10,
The dynamic range extension unit,
And calculating a maximum gain value for each of the representative colors by using a ratio of a maximum outputable brightness value for each of the representative colors and a maximum brightness value of each of the representative colors included in the image frame. The method of claim 14,
The dynamic range extension unit,
Based on the color characteristics and user preferences that can be output by the electronic device, a weight is determined for each representative color, a weight is applied to the calculated maximum gain value to calculate a final gain value for each representative color, and the input dynamics An electronic device comprising: applying the final gain value to a range to extend a dynamic range for each of the representative colors. The method of claim 15,
The dynamic range extension unit,
And determining a weight for each of the representative colors in consideration of a maximum gain value of an adjacent representative color. The method of claim 10,
The dynamic range extension unit,
And calculating a gain value between the representative colors by interpolating the gain values for the representative colors. The method of claim 10,
Further comprising; a region selection unit for selecting a region for extending the dynamic range of the input image frame;
The representative color determination unit,
And determining representative colors of a plurality of pixels included in the selected area.

Images