KR100455292B1 - Apparatus and method for controlling brightness of an imag - Google Patents

Abstract

Disclosed are an image brightness control apparatus and method for controlling the brightness of an image, and an adaptive image brightness control apparatus and method for adaptively controlling the brightness of an image according to a degree of brightness and / or a range of brightness of the image. The image brightness control device may include a brightness increase amount calculator configured to output a brightness increase amount of a predetermined pixel; And a brightness increase amount calculator for each component outputting a brightness increase amount for each component constituting the predetermined pixel in response to the brightness increase amount. The brightness increase amount calculator for each component multiplies the brightness increase amount for the predetermined pixel by a unit vector of each component constituting the predetermined pixel, and outputs the brightness increase amount for each component, and the image brightness controller is the predetermined pixel. And an addition calculating unit for adding each component constituting the component and an increase amount of brightness of each component. The image brightness control apparatus and the adaptive image brightness control apparatus according to the present invention have the effect of maintaining the color (image color or hue) of the image while increasing the brightness and the brightness range of the image.

Description

Apparatus and method for controlling brightness of an imag}

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a brightness control circuit. More particularly, the present invention relates to a brightness control circuit. Image brightness controller and method that can maintain a sense of color such as chroma and adaptive image brightness that adaptively controls the brightness of the image according to the degree of brightness and / or the range of brightness of the image It relates to a control device and a method thereof.

The image brightness controller is a circuit for controlling the brightness of a video image to be displayed. Since the image brightness control circuit described in US Patent No. 4717953 applies DC (offset) to the red, green, and blue signals constituting the video signal, the conventional video brightness control circuit has a limitation in increasing the brightness of the image.

As a method of controlling the brightness of an image, a method of controlling the brightness of an image by applying a gamma function to a Y signal and a gamma function of each red, green, and blue signal (hereinafter referred to as "RGB") signal There is a method of controlling the brightness of the image by applying. In the former case, the RGB signal is separated into one Y signal and two chrominance signals (Cb, Cr or I, Q), and then the brightness of the image is increased by using a gamma function on the Y signal and then converted into an RGB signal. How to convert.

However, this method can result in out of color gamut. The gamut deviation refers to a case where two color difference signals corresponding to Y signals having increased brightness do not exist. When color gamut deviation occurs, the image with increased brightness may not maintain the original color or / and saturation, and thus may cause a deterioration in image quality.

Since the latter applies nonlinear powers to each component of RGB, color shift occurs because the output RGB has a different ratio from the input RGB, that is, a different direction vector.

In addition, histogram equalization (Histogram equalization; Digital Image Processing, Wiley, 1978; co-authored by RC Gonzalez and RE Woods, Digital Image Processing, Addison-Wesley, 1993) to increase the brightness of an image ) And contrast, but the vector direction of the output color may be different from the vector direction of the input color, thereby causing a color shift.

Accordingly, the first technical problem to be achieved by the present invention is to provide an image brightness control apparatus and a method which can maintain the image color (hue or saturation, etc.) while increasing the brightness of the image.

The second technical problem to be achieved by the present invention is to provide an adaptive image brightness control apparatus and method for adaptively controlling the brightness of an image according to the degree of brightness of the image.

The third technical problem to be achieved by the present invention is to provide an adaptive image brightness control apparatus and method for adaptively controlling the brightness of the image according to the range of the brightness of the image.

The detailed description of each drawing is provided in order to provide a thorough understanding of the drawings cited in the detailed description of the invention.

1 is a diagram illustrating a representation of an RGB signal as a vector in an RGB color space.

2 is a block diagram of an apparatus for controlling brightness of an image according to a first exemplary embodiment of the present invention.

3 is a block diagram of an apparatus for controlling brightness of an image according to a second exemplary embodiment of the present invention.

4 is a block diagram of an apparatus for controlling brightness of an image according to a third exemplary embodiment of the present invention.

5 is a flowchart illustrating a brightness control method of an image according to a first exemplary embodiment of the present invention.

6 is a flowchart illustrating a method of controlling brightness of an image according to a second exemplary embodiment of the present invention.

7 is a flowchart illustrating a brightness control method of an image according to a third embodiment of the present invention.

8 is a first explanatory diagram for extracting an increase in brightness of an image according to the present invention.

9 is a second explanatory diagram for extracting an increase in brightness of an image according to the present invention.

10 is a third explanatory diagram for extracting an increase in brightness of an image according to the present invention.

11 is a fourth explanatory diagram for extracting an increase in brightness of an image according to the present invention.

12 is a fourth explanatory diagram for extracting an increase in brightness of an image according to the present invention.

FIG. 13 is a block diagram illustrating an adaptive image brightness controller according to the brightness level of an image according to an exemplary embodiment of the present invention.

14 is a detailed block diagram of the brightness enhancement parameter setting unit 160 illustrated in FIG. 13.

15 is a diagram illustrating brightness histograms of three images having different brightnesses.

16 is a flowchart illustrating an adaptive image brightness control method according to the brightness level of an image according to an embodiment of the present invention.

FIG. 17 is a detailed flowchart of operation 710 of FIG. 16.

FIG. 18 is a detailed flowchart of operation 730 shown in FIG. 16.

19 is a block diagram illustrating an adaptive image brightness control apparatus according to the brightness range or brightness range and brightness degree of an image according to an embodiment of the present invention.

20 is a diagram showing the detailed configuration of the parameter setting unit 170 shown in FIG.

21A and 21B are views illustrating a detailed configuration of the brightness range enhancer 180 illustrated in FIG. 19.

22 is a diagram illustrating a detailed configuration of the brightness controller 190 shown in FIG. 19.

23 is a flowchart illustrating an adaptive image brightness control method according to the brightness range or brightness range and brightness degree of an image according to an embodiment of the present invention.

FIG. 24 is a flowchart for describing the operation 850 of FIG. 23 in more detail.

The image brightness control apparatus for achieving the first technical problem comprises: a brightness increase amount calculator configured to output a brightness increase amount for a predetermined pixel; And a brightness increase amount calculator for each component outputting a brightness increase amount for each component constituting the predetermined pixel in response to the brightness increase amount.

The brightness increase amount calculator for each component multiplies the brightness increase amount for the predetermined pixel by a unit vector of each component constituting the predetermined pixel, and outputs the brightness increase amount for each component, and the image brightness controller is the predetermined pixel. And an addition calculating unit for adding each component constituting the component and an increase amount of brightness of each component.

Another image brightness controller for achieving the first technical problem, the image brightness controller includes a brightness calculator for outputting a brightness corresponding to a predetermined input signal; A reference value calculator for outputting a reference brightness corresponding to the brightness; A brightness increase amount calculator configured to output a brightness increase amount corresponding to a difference between the reference brightness and the brightness; An increase amount calculation unit for each component calculating and outputting an increase amount of each of the components constituting the predetermined input signal from the increase amount of brightness; And an operation unit configured to output an output signal having increased brightness by adding each component constituting the predetermined input signal and an output signal of the increase amount calculator for each component.

The increase amount calculator for each component multiplies the brightness increase amount by a unit vector of each element constituting the predetermined input signal and outputs the increase amount of each brightness element.

Another image brightness control apparatus for achieving the first technical problem,

A brightness parameter calculator for outputting a brightness parameter corresponding to an input video signal composed of a plurality of elements; A reference value calculator for outputting a reference brightness value corresponding to the output value; A brightness enhancement ratio dividing unit dividing the reference brightness value by an output value of the maximum component calculating unit to output a brightness enhancement ratio; And an element multiplier for multiplying and outputting each of the elements constituting the input video signal with the brightness enhancement ratio.

The brightness parameter calculating unit may be configured to set a brightness parameter as a value of an element having a maximum value among the elements constituting the input video signal.

The reference value calculator is further configured to output a reference brightness value corresponding to the output value by using a plurality of reference brightness value functions corresponding to the input control signal.

The image brightness control method for achieving the first technical problem comprises the steps of: outputting a brightness increase amount for a predetermined pixel; And outputting a brightness increase amount for each component constituting the predetermined pixel in response to the brightness increase amount.

The step of outputting the brightness increase amount for each component may include calculating the brightness increase amount for each component by multiplying the brightness increase amount for the predetermined pixel by a unit vector of each component constituting the predetermined pixel. The brightness control method includes adding each component constituting the predetermined pixel and an increase amount of the brightness of each component.

Another image brightness control method for achieving the first technical problem comprises the steps of: outputting the brightness for the element having the maximum value among the elements constituting a predetermined input signal; Outputting a reference brightness corresponding to the brightness for the element having the maximum value; Outputting a difference in brightness for the element having the reference brightness and the maximum value; Outputting a brightness increase amount corresponding to the brightness difference in response to the brightness difference and the elements constituting the input signal; Outputting a brightness increase amount for each element constituting the input signal in response to the elements constituting the input signal and the brightness increase amount; And adding each element constituting the input signal and the brightness increase amount for each element.

Another image brightness control method for achieving the first technical problem comprises: a brightness parameter calculating step of outputting a brightness parameter corresponding to an input video signal composed of a plurality of elements; A reference value calculating step of outputting a reference brightness value corresponding to the output value; Dividing the reference brightness value by an output value of the maximum component calculator to output a brightness enhancement ratio; And an element-specific multiplication step of multiplying and outputting each of the elements constituting the input image signal to the brightness enhancement ratio.

In the calculating of the brightness parameter, a brightness parameter may be a value of an element having a maximum value among elements constituting the input image signal.

Adaptive image brightness control apparatus according to the brightness level of the image for achieving the second technical problem, the brightness to determine the degree of increase and decrease of the image brightness in response to the input image signal and a predetermined control signal composed of a plurality of elements A brightness enhancement parameter setting unit for outputting an enhancement parameter; And a brightness controller configured to control brightness of an image in response to the brightness enhancement parameter and the input signal.

The brightness controller may include a brightness parameter calculator configured to output a brightness parameter corresponding to the input image signal; A reference value calculator for outputting a reference brightness value corresponding to the output value; A brightness enhancement ratio dividing unit dividing the reference brightness value by an output value of the maximum component calculating unit to output a brightness enhancement ratio; And an element multiplier for multiplying and outputting each of the elements constituting the input video signal with the brightness enhancement ratio.

The brightness parameter calculator may be configured to set a brightness parameter as a value of an element having a maximum value among elements constituting the input video signal.

Adaptive image brightness control method according to the brightness level of the image for achieving the second technical problem, the brightness to determine the degree of increase and decrease of the image brightness in response to the input image signal and a predetermined control signal composed of a plurality of elements A brightness enhancement parameter setting step of outputting an enhancement parameter; And a brightness control step of controlling brightness of an image in response to the brightness enhancement parameter and the input signal.

The brightness control step may include a brightness parameter calculation step of outputting a brightness parameter corresponding to the input image signal; A reference value calculating step of outputting a reference brightness value corresponding to the output value; Dividing the reference brightness value by an output value of the maximum component calculator to output a brightness enhancement ratio; And an element multiplication step of multiplying and outputting each of the elements constituting the input image signal to the brightness enhancement ratio.

In the calculating of the brightness parameter, a brightness parameter may be a value of an element having a maximum value among elements constituting the input image signal.

The adaptive image brightness control apparatus according to the brightness range of the image for achieving the third technical problem, in response to the input image signal and a predetermined control signal consisting of a plurality of elements, and the maximum value of the brightness of the input image signal; A parameter setting unit for outputting a maximum value and a minimum value of the minimum value and the extended brightness; And a brightness range of the input image signal is extended in response to the input image signal, the plurality of output values of the parameter setting unit, a maximum reference value and a minimum reference value of brightness of a predetermined image signal, and a maximum reference value and a minimum reference value of extended brightness. It has a brightness range improving unit for outputting a brightness signal,

The brightness range enhancing unit may include: a brightness parameter calculating unit configured to output a brightness parameter corresponding to the input image signal; A section comparator comparing the brightness parameter with a maximum value and a minimum value of the brightness of the input image signal to determine which section the brightness parameter belongs to and output section information; And a section brightness signal calculator for outputting a brightness parameter of which the brightness range is extended in response to the section information and the brightness parameter.

The brightness parameter calculator may be configured to set a brightness parameter as a value of an element having a maximum value among elements constituting the input video signal.

Adaptive image brightness control method according to the brightness range of the image to achieve the third technical problem, in response to the input image signal and a predetermined control signal consisting of a plurality of elements, the maximum value of the brightness of the input image signal and A parameter setting step of outputting a maximum value and a minimum value of the minimum value and the extended brightness; And a brightness range of the input image signal is extended in response to the input image signal, the plurality of output values of the parameter setting unit, a maximum reference value and a minimum reference value of brightness of a predetermined image signal, and a maximum reference value and a minimum reference value of extended brightness. And a brightness range improving step of outputting a brightness signal.

In order to fully understand the present invention, the operational advantages of the present invention, and the objects achieved by the practice of the present invention, reference should be made to the accompanying drawings which illustrate preferred embodiments of the present invention and the contents described in the accompanying drawings.

Hereinafter, exemplary embodiments of the present invention will be described in detail with reference to the accompanying drawings. Like reference numerals in the drawings denote like elements.

1 shows RGB represented as a vector in an RGB color space. 1 is a diagram illustrating R (red), G (green), and B (Blue) signals as vectors having directions and sizes in an RGB color space.

Each pixel P_1, P_2, or P_3 may be represented as a vector having a predetermined size (L_A, L_C, or (L_A + L_F)) and a direction in the RGB color space, and the size (L_A, L_C, Or (L_A + L_F) represents the brightness of each pixel P_1, P_2, or P_3, and the direction of each vector represents a sense of color.

The predetermined pixel P_1 is represented by a vector having a predetermined size L_A and a direction. Referring to FIG. 3, the size of the pixel P_3 is increased by L_F compared to the size L_A of the original pixel P_1, and the direction of the pixel P_3 is the same as the direction of the original pixel P_1. Therefore, the brightness of the pixel P_3 is increased compared to the brightness of the original pixel P_1, and since the direction of the pixel P_3 and the direction of the original pixel P_1 are the same, the color of the pixel P_3 and the original pixel ( The color of P_1) is the same. An image brightness controller and method according to an embodiment of the present invention is to make a pixel (P_3) for the pixel (P_1).

However, although the size L_C of the pixel P_2 is increased compared to the size L_A of the original pixel P_1, the direction of the pixel P_2 and the direction of the original pixel P_1 are different from each other. Therefore, the brightness of the pixel P_2 is increased compared to the brightness of the original pixel P_1, but since the direction of the pixel P_2 and the direction of the original pixel P_1 are different from each other, the color of the pixel P_2 and the original The color of the pixel P_1 is different from each other. Therefore, there is a problem in that the image quality is degraded.

2 is a block diagram of an image brightness control apparatus according to a first embodiment of the present invention. Referring to FIG. 2, the image brightness controller 100 may include a maximum component calculator 10, a reference value calculator 20, a gain controller 30, a brightness difference calculator 40, a brightness increase calculator 50, and an RGB increase calculator. 60 and an add operation unit 70 is provided.

The brightness increase calculator 50 includes R / G / B channel unit vector calculators 61, 63, and 65, a channel selector 51, and a brightness increase calculator 53, and the RGB increase calculator 60 respectively. R / G / B channel unit vector calculating sections 61, 63, and 65 and an RGB increasing amount calculating circuit 67 are provided.

The maximum component calculating unit 10 includes a red signal Ri having a maximum value among three signals Red (Ri), Green (Gi), or Blue (Bi) constituting a predetermined input signal (or pixel), The green signal Gi or the blue signal Bi is output to the reference value calculator 20, the brightness difference calculator 40, and the brightness increase amount calculator 50. That is, the maximum component calculating unit 10 may determine the value of the signal having the maximum value among the red signal Ri, the green signal Gi, or the blue signal Bi constituting the predetermined input signal. In the following description, " brightness of maximum component (signal) "

The reference value calculator 20 corresponds to a reference brightness corresponding to the output signal Y of the maximum component calculator 10 in response to the output signal Gval of the gain controller 30 and the output signal Y of the maximum component calculator 10. Ref_Y is calculated, and the reference brightness Ref_Y is output to the brightness difference calculator 40. The output signal Gval of the gain controller 30 may be controlled by the user. That is, the reference value calculator 20 calculates the reference brightness Ref_Y corresponding to the output signal Y of the maximum component calculator 10. The reference brightness Ref_Y may be calculated using a predetermined lookup table corresponding to the output signal Y of the maximum component calculating unit 10.

The brightness difference calculator 40 calculates the brightness difference dif_Y of the output signals Ref_Y and Y in response to the reference brightness Ref_Y and the brightness Y of the maximum component, and calculates the brightness difference dif_Y by increasing the brightness. Output to arithmetic unit 50. That is, the brightness difference calculator 40 outputs the brightness difference dif_Y between the two signals Ref_Y and Y in response to the brightness Y of the original input signal and the reference brightness Ref_Y.

The brightness increasing amount calculating section 50 responds to a predetermined input signal, the output signal of the maximum component calculating section 10 and the output signal dif_Y of the brightness difference calculating section 40, to the brightness Y of the maximum signal (component). The brightness increase amount Inc_Y is calculated, and the brightness increase amount Inc_Y is output to the RGB increase amount calculator 60.

The RGB increase amount calculating unit 60 calculates each RGB increase amount Inc_r, Inc_G, Inc_B for each RGB in response to a predetermined input signal and the output signal Inc_Y of the brightness increase amount calculating unit 50, and calculates the RGB increase amount Inc_R. , Inc_G, Inc_B) is output to the add operation unit 70. Each RGB increase amount Inc_R, Inc_G, Inc_B is calculated by multiplying the output signal Inc_Y of the brightness increase amount calculation unit 50 with the unit vectors for red, green, and blue constituting a predetermined input signal.

The add operation unit 70 outputs output signals Ro, Go, and Bo that are the sum of the RGB signals constituting the predetermined input signal and the output signals Inc_R, Inc_G, Inc_B of the RGB increase amount calculator 60.

R / G / B channel unit vector calculators 61, 63, and 65 are unit vectors R_vec and G_vec for the red signal Ri, the green signal Gi, and the blue signal Bi, respectively, inputted to the respective channels. , B_vec is calculated, and the unit vectors R_vec, G_vec, and B_vec are output to the channel selector 51 and the RGB increase amount calculation circuit 60. The channel selector 51 selects one of the output signals R_vec, G_vec, and B_vec of the R / G / B channel unit vector calculators 61, 63, and 65 in response to the output signal of the maximum component calculator 10. Then, the selected signal is output to the brightness increasing amount calculating circuit 75. The channel selector 51 preferably outputs the maximum unit vector.

The brightness increase amount calculation circuit 53 multiplies the output signal of the channel selector 51 and the output signal dif_Y of the brightness difference calculator 40, and outputs the result to the RGB increase amount calculation circuit 67. The RGB increase amount calculating circuit 67 outputs the output signals Inc_Y of the brightness increase amount calculating circuit 53 and the output signals R_vec, G_vec, and B_vec of each of the R / G / B channel unit vector calculating units 61, 63, and 65, respectively. Each R / G / B channel is multiplied and the result (Inc_R, Inc_G, Inc_B) is output to the add operation unit 70.

3 is a block diagram of an image brightness control apparatus according to a second embodiment of the present invention. The image brightness control apparatus 200 of FIG. 3 includes a reference value calculator 20, a gain controller 30, a brightness calculator 110, a brightness increase calculator 130, an RGB increase calculator 60, and a multiplication calculator 70. do. Since the image brightness control apparatus 200 of FIG. 3 is similar to the image brightness control apparatus 100 of FIG. 2, only the brightness calculator 110 and the brightness increase calculator 130 will be described.

The brightness calculator 110 calculates a brightness Y for a predetermined input signal composed of RGB, and outputs the result to the reference value calculator 20 and the brightness increase calculator 130. The brightness increasing amount calculating unit 130 calculates a brightness difference (dif_Y) between the output signal Ref_Y of the reference value calculating unit 20 and the output signal Y of the brightness calculating unit 110, and calculates the brightness difference dif_Y from the RGB increasing amount calculating unit ( 60). In this case, the brightness difference dif_Y is equal to the brightness increase amount Inc_Y.

The RGB increase amount calculator 60 calculates each RGB increase amount Inc_R, Inc_G, Inc_B in response to a predetermined input signal and the output signal dif_Y of the brightness increase amount calculator 130, and calculates the RGB increase amount InccR, Inc_G, Inc_B. ) Is output to the add operation unit 70. The addition operator 70 outputs the output signals Ro, Go, and Bo that are the sum of the input signals Ri, Gi, Bi, and the output signals Inc_R, Inc_G, Inc_B of the RGB increase amount calculator 60.

4 is a block diagram of an image brightness control apparatus according to a third embodiment of the present invention. The image brightness controller 300 of FIG. 4 includes a brightness parameter calculator 145, a reference value calculator 20, a brightness enhancement ratio divider 140, and an RGB multiplier 150.

The brightness parameter calculator 145 receives the image signals Ri, Gi, and Bi, determines the brightness parameters of the input image, and outputs the brightness parameters to the reference value calculator 20 and the brightness enhancement ratio divider 140. There are many ways to determine brightness parameters. As an example, the maximum value among the values of Ri, Gi, and Bi elements constituting the input video signal may be determined as the brightness parameter.

Since the reference value calculator 20 is the same as described above, a description thereof will be omitted.

The brightness enhancement ratio divider 140 receives a reference brightness value from the reference value calculator 20, receives a brightness parameter from the brightness parameter calculator 145, divides two input signal values, and then divides the result into an RGB multiplier. Output to 150. The RGB multiplier 150 multiplies the brightness enhancement ratio received from the brightness enhancement ratio divider 140 with respect to each of the input image signals Ri, Gi, and Bi, and outputs signals having enhanced brightness (Ro, Go, Bo). Let's do it.

5 is a flowchart illustrating an image brightness control method according to a first embodiment of the present invention. A method of increasing the brightness of a predetermined input signal Ri, Gi, Bi with reference to FIGS. 1, 2 and 5 is as follows.

The maximum component calculating unit 10 receives a predetermined input signal (or pixel) composed of a red signal Ri, a green signal Gi, and a blue signal Bi (step 400), and receives a red signal Ri and green. A red signal Ri, a green signal Gi, or a blue signal Bi having the maximum value among the signal Gi and the blue signal Bi is obtained through Equation 1 (step 410).

Here, Y means the value of the signal having the maximum value among the three signals Ri, Gi, and Bi constituting a predetermined input signal (or pixel). The maximum component calculator 10 outputs the brightness Y for the maximum signal (or component) to the reference value calculator 20, the brightness difference calculator 40, and the brightness increase calculator 50.

In response to the output signal Gval of the gain control unit 30 (step 421), the reference value calculator 20 generates a reference brightness Ref_Y corresponding to the brightness Y of a predetermined input signal or a maximum signal (or component). Is calculated through Equation 2, and the reference brightness Ref_Y is output to the brightness difference calculator 40 (step 420).

Here Ref_Y is F (Y), F (Y) is a function of the brightness (Y) for the maximum signal (or component) represented by the equation (1). That is, the reference brightness Ref_Y is determined by the brightness Y for the maximum signal (or component) and the output signal Gval of the gain control unit 30.

8 is a first explanatory diagram for extracting the increase in brightness according to the present invention. Referring to Figure 8, the function F () is expressed as shown in equation (3).

Where g1 is a scale constant, g2 is an offset constant, and Gval is a constant representing a power (square). x means brightness (Y), and x_max corresponds to white (for example, when R, G, and B are all at maximum) at maximum brightness (Y).

The diagonal line indicated by the dotted line represents the slope 1, the function F () represents the reference brightness Ref_Y as a nonlinear function, the point B1 represents the brightness Y of the original input signal or pixel, and the point B2 Denotes the reference brightness Ref_Y generated by the function F (). That is, B1 is Y, that is, B2 is Ref_Y.

9 is a second explanatory diagram for extracting the increase in brightness according to the present invention. The function F (x) of FIG. 9 is composed of two nonlinear functions, and the function F (x) is represented by Equation 4.

Here, x_th represents the boundary value of the brightness interval, g11 represents the scale constant of the first section, g21 represents the offset constant of the first section, and Gval1 represents the power of the first section. In addition, g12 represents a scale constant of the second section, g22 represents an offset constant of the second section, and Gval2 represents a power of the second section.

The functions F1 () and F2 () are nonlinear functions that represent the reference brightness (Ref_Y), the point (B1) represents the brightness (Y) of the original input signal or pixel, and the point (B2) is determined by the function F1 (). It means the generated reference brightness (Ref_Y). That is, B2 is Ref_Y.

If m nonlinear functions are used, the function F (x) is expressed as in Equation 5.

Where k represents a designator that specifies the interval, g1 (k) represents the scale constant in section k, g2 (k) represents the offset constant in section k, and Gval (k) represents the power of Indicates. The illustration of the function represented by Equation 5 is omitted.

10 is a third explanatory diagram for extracting the increase in brightness according to the present invention. 10 is another configuration example of the function F (x) used in the present invention, in which the function F (x) is represented by linear functions.

Here, k represents a designator for designating a section, s1 represents a straight slope, and s2 represents an offset. Further, the functions F1 () and F2 () represent the reference brightness Ref_Y as a linear function, the point B1 represents the brightness Y of the original input signal or pixel, and the point B2 represents the function F1 (). It means the reference brightness (Ref_Y) generated by the. That is, B2 is Ref_Y.

11 is a fourth explanatory diagram for extracting the increase in brightness according to the present invention. The function of FIG. 11 is composed of a linear function F2 () and a nonlinear function F1 (). Where B1 is Y and B2 is Ref_Y.

12 is a fourth explanatory diagram for extracting the increase in brightness according to the present invention. Function of FIG. 12 The function F () of Equation (3) is a graph that appears when g1 = 1, g2 = 0, and Y_Gval value is greater than 1, and may be used to decrease the brightness of the input image. Point B1 denotes the brightness value (Y = B1) of the original pixel, and point B3 denotes the reference brightness value (Ref_Y = B3) generated by the function F ().

Since the function F () of FIGS. 8 to 12 is a function for explaining an embodiment of the present invention, the function according to the present invention is not limited to the function F () of FIGS. 8 to 12.

The brightness difference calculator 40 calculates the brightness difference dif_Y represented by Equation 7 in step 430. In other words, the brightness difference calculator 40 calculates the difference between the point B2 and the point B1.

Referring to Equations 3 and 7, if the squared Gval is less than or equal to 1, the reference brightness Ref_Y for brightness Y is increased, and if the squared Gval approaches zero, the brightness difference (dif_Y) is increased. Therefore, the brightness difference (dif_Y) is controlled in response to the square of Gval.

The brightness increase amount calculator 50 calculates the brightness increase amount Inc_Y through Equation 8 in response to the output signal of the channel selector 51 and the output signal dif_Y of the brightness difference calculator 40 (step 440).

Here, Max_Vector refers to a unit vector of a signal (or component) having a maximum value among the red signal Ri, the green signal Gi, and the blue signal Bi constituting a predetermined input signal (or pixel). In this case, the brightness difference dif_Y represents the brightness increase amount Inc_Y for all the RGB components.

The RGB increasing amount calculating part 60 responds to the output signal Inc_Y of the brightness increasing amount calculating part 50 and the respective output signals R_vec, G_vec, and B_vec of each channel unit vector calculating part 61, 63, and 65 by equation (9). An increase amount Incc_R, Inc_G, Inc_B of each of the red signal Ri, the green signal Gi, and the blue signal Bi constituting the predetermined input signal (or pixel) to be expressed is calculated (step 450).

Inc_R = Inc_Y × R_vec

Inc_G = Inc_Y × G_vec

Inc_B = Inc_Y × B_vec

R_vec = b1 × Ri ÷ M1

G_vec = b1 × Gi ÷ M1

B_vec = b1 × Bi ÷ M1

Here, b1 represents a scale constant, and R_vec, G_vec, and B_vec each represent unit vectors for the red signal Ri, the green signal Gi, and the blue signal Bi.

The add operation unit 70 responds to the red signal Ri, the green signal Gi, and the blue signal Bi and the output signals Inc_R, Inc_G, Inc_B of the RGB increase amount calculation unit 60 constituting a predetermined input signal. The red signal Ro, the green signal Go, and the blue signal Bo with increased brightness are output. The red signal Ro, the green signal Go, and the blue signal Bo are expressed as in Equation 10.

Each of the red signal Ro, the green signal Go, and the blue signal Bo whose brightness is increased is the original red signal Ri, the green signal Gi, the blue signal Bi, and the brightness increments Inc_R, Inc_G, Inc_B). Therefore, the brightness control apparatus 100 of an image according to an embodiment of the present invention has the effect of maintaining the original color, saturation and the like while increasing the brightness of the input signal.

In addition, since the brightness increase amount of the output signals Ro, Go, Bo cannot exceed the maximum brightness, the output signals Ro, Go, Bo do not exceed the respective maximum values in the RGB space.

6 is a flowchart illustrating an image brightness control method according to a second embodiment of the present invention. A method of increasing the brightness of the input signals Ri, Gi, and Bi will be described with reference to FIGS. 3 and 6. 6 is similar to FIG. 5, so only the characteristic parts of FIG. 6 will be described in detail.

The brightness calculator 110 receives a predetermined input signal consisting of red (Ri), green (Gi), and blue (Bi) (step 500), and calculates the brightness (Y) of the input signal through Equation (11). do. That is, the brightness calculator 110 calculates the brightness Y of the predetermined input signal in response to the red signal Ri, the green signal Gi, and the blue signal Bi constituting the predetermined input signal.

Here, each of a1, a2, and a3 is a constant indicating the weight of the RGB signal constituting the predetermined input signal. The reference value calculator 20 obtains the reference brightness Ref_Y through Equation 2 in response to the output signal Y of the brightness calculator 110 (step 520).

In response to the brightness (Y) and the reference brightness (Ref_Y) of the input signal, the brightness increasing amount calculating unit 130, the brightness difference (dif_Y) between the brightness (Y) and the reference brightness (Ref_Y) for the input signal through Equation 12 Obtain (step 530). In this case, the brightness difference (dif_Y) is the brightness increase amount (Inc_Y).

The RGB increasing unit 60 expresses the output signal Inc_Y of the brightness increasing unit 50 and the output signals R_vec, G_vec, and B_vec of the channel unit vector calculating units 61, 63, and 65 by Equation (9). Each brightness increase amount Incc_R, Inc_G, Inc_B of the RGB to be calculated is calculated (step 540).

The addition operator 70 outputs output signals Ro, Go, and Bo with increased brightness in response to each of the three signals constituting the input signal and the respective brightness increasing amounts Inc_R, Inc_G, Inc_B. The output signals Ro, Go, and Bo are represented by Equation 10.

7 is a flowchart illustrating a method of controlling image brightness according to a third embodiment of the present invention. A method of increasing the brightness of the input signals Ri, Gi, and Bi will be described with reference to FIGS. 4 and 7.

First, image signals Ri, Gi, and Bi are input to the brightness parameter calculator 145 (step 600).

In order to improve the brightness within the color gamut represented by the input signals Ri, Gi, and Bi, brightness parameters indicating the brightness of the input signal are required. There are many ways to get the brightness parameters. The first method is to set the maximum of three components as the brightness parameter for arbitrary pixel values Ri, Gi, and Bi in the RGB color space. That is, the brightness parameter calculator 145 calculates the brightness parameter Y_ch by using Equation 1 described above (operation 610).

The second method for obtaining the brightness parameter is obtained by the above equation (11). The third method is to use nonlinear equations.

Where q1 is a scale constant, q3 is an offset value, q2 is a power of a power, Y is a linear brightness value for RGB, and may be Yc. Ymax is the maximum value of brightness, and L is the nonlinear brightness for the inputs Ri, Gi, and Bi. For CIE L *, an international standard color space, q1 = 116, q2 = 1/3, and q3 = 16 are used.

After operation 610, the reference value calculator 20 obtains a reference brightness value Ref_Y (operation 620). At this time, the brightness enhancement parameter Y_Gval is input as a control signal (step 630). The reference brightness value Ref_Y is expressed as in Equation 2. Here, the function F () is a function of the brightness Y_ch (or Yc, L), an example of F () is shown in FIGS. 8 to 12, and the description of FIGS. 8 to 11 is as described above. 12 degrees is a graph indicating when the function F () is equal to g1 = 1, g2 = 0, and Y_Gval value is greater than 1, and may be used to decrease the brightness of the input image. In FIG. 12, point B1 denotes a brightness value of an original pixel, and point B3 denotes a reference brightness value Ref_Y = B3 generated by the function F ().

After operation 620, the brightness enhancement ratio divider 140 obtains a brightness enhancement ratio Brt_ratio which is a ratio of the brightness value Y_ch and the reference brightness value Ref_Y of the input pixel (operation 640).

Equation 14 is used to calculate the brightness enhancement ratio for any input pixel.

After operation 640, the RGB multiplier 150 multiplies each of the RGB components of the input pixel by the brightness enhancement ratio obtained in operation 640 to obtain an output pixel value having improved brightness (operation 650).

Ref_Y in Equation 14 is a value within the gamut range in the RGB color space, and Ref_Y, which is the enhancement ratio of the maximum value in RGB, is also a value within the gamut range, so that the values of the other two components equal to or less than the maximum value in RGB are also multiplied by the same enhancement ratio. When these are also values within the gamut range.

After operation 650, the output signals Ro, Go, and Bo with enhanced brightness are output from the RGB multiplier 150 (operation 660).

In Equation 3, brightness enhancement parameters such as g1, g2, and Y_Gval are required. These brightness enhancement parameters can be adjusted to respective values by user control.

FIG. 13 is a block diagram illustrating an adaptive image brightness control apparatus according to the brightness level of an image according to an exemplary embodiment of the present invention, and includes a brightness enhancement parameter setting unit 160 and a brightness control unit 169.

First, the brightness enhancement parameter setting unit 160 receives the image signals Ri, Gi, and Bi, and receives a control signal including a scale value necessary for brightness enhancement and calculates a brightness enhancement parameter. Reference average brightness Y_refer, DR_high, DR_low, ScaleFu and ScaleFd are used as control signals, which will be described later with reference to FIG.

The brightness controller 169 receives the brightness enhancement parameter Y_Gval, which is the output of the brightness enhancement parameter setting unit 160, controls the brightness of the image signal and outputs an improved brightness signal. The brightness controller 169 outputs an improved brightness signal. Brightness control devices 100, 200, and 300 described in 4 may be used.

FIG. 14 is a detailed block diagram of the brightness enhancement parameter setting unit 160 shown in FIG. 13, and includes an RGB signal converter 161, an average brightness calculator 163, and a parameter calculator 165.

First, the RGB signal converter 161 receives the image signals Ri, Gi, and Bi, converts the image signals into brightness signals Y, and outputs them to the average brightness calculator 163. However, if the brightness signal is input in the form of Y, Cb, Cr instead of RGB, the RGB signal converter 161 is unnecessary.

The average brightness calculator 163 calculates an average of the input brightness values and outputs the result to the parameter calculator 165. When the image is processed in units of frames, the brightness values of the pixels of one frame are averaged.

The parameter calculator 165 receives the average brightness from the average brightness calculator 163, receives a control signal containing a scale value necessary for brightness enhancement, calculates the brightness enhancement parameter Y_Gval, and then calculates the brightness enhancement parameter 169. )

16 is a flowchart illustrating an adaptive image brightness control method according to the brightness level of an image according to an embodiment of the present invention. A method of adaptively increasing the brightness of an image according to the brightness of the input signals Ri, Gi, and Bi will be described with reference to FIGS. 13 through 16.

A representative parameter indicating the degree of brightness of the image is the average brightness of the image. FIG. 15 is a diagram showing brightness histograms of three images having different brightnesses, and shows a distribution of brightness signals of the image, D1 when the brightness of the image is dark, D2 for medium brightness, and D3 when light. The average brightnesses representing the brightness levels of D1 to D3 are denoted as Dc1, Dc2, and Dc3, respectively.

In FIG. 16, one frame image is input to the brightness enhancement parameter setting unit 160 and the brightness control unit 169 (operation 700).

The average brightness calculator 163 calculates average brightness of the input image (operation 710).

The parameter calculator 165 receives the average brightness and calculates a brightness enhancement parameter Y_Gval according to the control signal (operation 730).

In operation 750, the brightness controller 169 calculates an improved brightness value for each pixel in response to the brightness enhancement parameter and the input image signal. Calculation of the improved brightness value can be obtained as shown in FIGS. 5 to 7 described above.

The brightness controller 169 outputs the improved brightness value (operation 760).

FIG. 17 is a detailed flowchart of operation 710 of FIG. 16. The steps shown in FIG. 17 are performed by the average brightness calculator 163 shown in FIG. Hereinafter, operation 710 of calculating the average brightness will be described in detail with reference to FIG. 17.

The average brightness Y_mean of the image is expressed as in Equation 16 below.

Here, Yc is a parameter representing brightness and can be expressed by Equation 1, the subscript i is an index representing arbitrary spatial coordinates in the image, and N is the total number of pixels of the image.

First, count i = 0 and brightness sum (Y_sum) = 0 immediately before the start of one frame image (step 711).

The pixel values Ri, Gi, and Bi are received (operation 712).

In operation 713, brightness values of the input pixel values Ri, Gi, and Bi of the position corresponding to count i are calculated. In operation 713 of the figure, the brightness value represented by Equation 11 is shown. However, the brightness value can be obtained by Equation 1 or Equation 13, of course.

The brightness value obtained in operation 713 is added to the brightness sum Y_sum (operation 714).

After operation 714, it is compared whether count i is smaller than the total number of pixels constituting the frame image (operation 715).

If count i is smaller than the total number of pixels, the count i is increased by one, and then the process returns to step 712 to repeat steps (step 716).

If count i is not smaller than the total number of pixels in step 715, the average brightness Y_mean of the image is calculated by dividing the sum of brightnesses Y_sum by the total number of pixels (step 717).

FIG. 18 is a detailed flowchart of operation 730 shown in FIG. 16. The steps shown in FIG. 18 are performed by the parameter calculator 165 shown in FIG. Hereinafter, operation 730 of calculating the brightness enhancement parameter Y_Gval will be described in detail with reference to FIG. 18.

First, an average brightness difference Y_differ between the average brightness Y_mean and the reference average brightness Y_refer of the image obtained in operation 710 is obtained (operation 731). In order to determine the increase or decrease of brightness according to the average brightness Y_mean of the image, the reference average brightness Y_refer is used as a reference of the average brightness. The reference average brightness is an average brightness value when the brightness of the image is not needed. Therefore, when the input average brightness value is smaller than the reference average brightness value, the brightness of the image is increased, and when the input average brightness value is larger than the reference average brightness value, the brightness of the image is required. As a method of increasing or decreasing the brightness of an image, the gamma index Y_Gval in Equation 3 may be used as a brightness enhancement parameter.

After the step 731, if the average brightness difference Y_differ has a positive number, the brightness enhancement parameter Y_Gval is calculated using Equation 17 (step 735).

If the average brightness difference Y_differ has a negative number, the brightness enhancement parameter is calculated using Equation 18 (step 737).

In Equations 17 and 18, G_def represents a reference value of the brightness enhancement parameter Y_Gval, which is a gamma index with respect to the reference average brightness value, DR_high is the maximum allowable value for the average brightness of the image, and DR_low is an image of the image. The minimum allowable value for average brightness, and the scale factors ScaleFu and ScaleFd are values representing the maximum and minimum allowable ranges of the gamma index, respectively. As an example of each value, G_def = 1, Y_refer = 168, DR_high = 250, DR_low = 50, ScaleFu = ScaleFd = 0.5 can be used. The reference average brightness Y_refer, DR_high, DR_low, ScaleFu and ScaleFd are used as predetermined control signals input to the brightness enhancement parameter setting unit 160 shown in FIG. 13 and can be adjusted by a user or a chipmaker.

19 is a block diagram illustrating an adaptive image brightness control apparatus according to the brightness range or brightness range and brightness level of an image according to an exemplary embodiment of the present invention. The controller 190 is configured.

First, the parameter setting unit 170 includes a control signal containing a scale value necessary for image brightness Ri, Gi, Bi, and brightness enhancement, a control signal LowScale containing a scale value of the minimum brightness range, and a maximum brightness range. The control signal (HighScale) containing the scale value of the value is received. Here, the control signal containing the scale value required for brightness enhancement is the same as the control signal input to the brightness enhancement parameter setting unit 160 shown in FIG. 13. That is, the maximum allowable range of the brightness enhancement parameter, which is the gamma index, as the reference average brightness value (Y_refer), the maximum allowable value (DR_high) for the average brightness of the image, the minimum allowable value (DR_low) for the average brightness of the image, and the scale factor. It is a value indicating scaleFu and a value indicating scale minimum allowed range of the gamma index (ScaleFd). According to the presence or absence of a control signal input to the brightness enhancement parameter setting unit 160 or a control signal containing a scale value of the brightness range, the adaptive image brightness controller shown in FIG. 19 depends on the brightness range or the brightness degree. Alternatively, the function to adaptively control the brightness of the image according to the brightness range and the brightness degree.

The parameter setting unit 170 outputs the brightness enhancement parameters to the brightness control unit 190, while the four types of brightness range enhancement parameters, that is, the minimum value of the brightness of the input signal (Y_low) and the maximum value of the brightness of the input signal (Y_high). When the brightness range is extended, the minimum value AppYL of the extended brightness range and the maximum value AppYH of the extended brightness range are output to the brightness range enhancement unit 180 when the brightness range is extended.

The brightness range enhancement unit 180 receives the four kinds of brightness range enhancement parameters Y_low, Y_high, AppYL, and AppYH described above from the parameter setting unit 170, and the brightness range parameter from the MICOM (not shown). Input reference brightness range maximum value (ReferYH), reference brightness range minimum value (ReferYL), reference brightness range maximum value of extended brightness range (ReferYoH) and reference brightness range minimum value of extended brightness range (ReferYoL) are input. The brightness range is improved for each pixel by receiving the image signals Ri, Gi, and Bi, and the result is output to the brightness controller 190.

The brightness controller 190 receives a brightness enhancement parameter from the parameter setting unit 170, and receives a signal having an improved brightness range from the brightness range enhancer 180. The brightness controller 190 receives a pixel for the image signals Ri, Gi, and Bi. After calculating the brightness enhancement for each, and outputs a signal with improved brightness (Ro, Go, Bo).

FIG. 20 is a diagram illustrating a detailed configuration of the parameter setting unit 170 illustrated in FIG. 19, and includes a brightness enhancement parameter setting unit 160 and a brightness range enhancement parameter setting unit 171. The brightness range enhancement parameter setting unit 178 is an RGB signal converter 161, a brightness minimum value calculator 174, a brightness maximum value calculator 176, a second parameter calculator 175, and a third parameter calculator 177. It is composed. The brightness enhancement parameter setting unit 160 is as described above.

Since the brightness enhancement parameter setting unit 160 is the same as described above, description thereof will be omitted and the brightness range enhancement parameter setting unit 178 will be described below.

First, as described above, the RGB signal converter 161 converts an input image signal into a brightness signal and outputs the brightness signal to the brightness minimum value calculator 174 and the brightness maximum value calculator 176, respectively. Therefore, it is unnecessary when the input signal is a signal including a brightness signal rather than an RGB form.

The brightness minimum value calculator 174 obtains the minimum value Y_low among the input brightness values and outputs the result to the second parameter calculator 175 and the brightness range enhancer 180.

The second parameter calculator 175 receives the brightness minimum value Y_low, receives the control signal LowScale that contains the scale value of the brightness range minimum value, calculates the applied brightness minimum value parameter AppYL, and then brightnesses it. Output to the range enhancement unit 180.

The brightness maximum calculator 176 obtains the maximum value Y_high among the input brightness values and outputs the result to the third parameter calculator 177 and the brightness range enhancer 180.

The third parameter calculator 177 receives the maximum brightness value Y_high and, on the other hand, calculates an applied maximum brightness parameter AppYH by receiving a control signal HighScale containing a scale value of the maximum brightness range. This is output to the brightness range improving unit 180.

21A and 21B illustrate embodiments of the detailed configuration of the brightness range enhancer 180 illustrated in FIG. 19.

First, the brightness range improving unit 180 of FIG. 21A includes a brightness parameter calculator 145, a section comparator 181, a section selector 189, and a section brightness signal calculator 182. The calculator 182 includes a first section calculator 183, a second section calculator 185, and a third section calculator 187.

Since the brightness parameter calculator 145 is the same as described above, a detailed description thereof will be omitted. The brightness parameter Y_ch, which is the output of the brightness parameter calculator 145, is input to the brightness controller 190, and the interval comparator 181 is performed. The first section operator 183, the second section operator 185, and the third section operator 187 are input.

The interval comparator 181 receives the brightness parameter Y_ch from the brightness parameter calculator 145 and receives Y_low and Y_high, which are the minimum and maximum values of the interval range of the input image, from the parameter setting unit 170, respectively. The brightness parameter Y_ch is compared with Y_low and Y_high to determine which section is smaller than Y_low, between Y_low and Y_high, and larger than Y_high to determine which section, and the corresponding section information is selected from the section selector 189. To the output.

The first interval calculator 183 receives the brightness parameter Y_ch from the brightness parameter calculator 145. Meanwhile, the minimum and maximum values of one section range of the input image are received from the parameter setting unit 170 and the minimum value Y_low of the input signal and the minimum value AppYL of the extended brightness range when the brightness range is expanded. By inputting the reference brightness range minimum value (ReferYL) and the reference brightness range minimum value (ReferYoL) of the extended brightness range from the microcomputer (not shown), the brightness range is improved for Y_ch and the result is selected by the interval selection unit. (189).

The second section calculator 185 receives the brightness parameter Y_ch from the brightness parameter calculator 145. Meanwhile, Y_low, Y_high, AppYL, and AppYH are inputted from the parameter setting unit 170 as the minimum and maximum range values of the two sections of the input image, the brightness range is improved for Y_ch, and the result is selected as the section selector ( 189).

The third section calculator 187 receives the brightness parameter Y_ch from the brightness parameter calculator 145. Meanwhile, Y_high and AppYH are inputted from the parameter setting unit 170 to the minimum and maximum values of the three-section range of the input image, and the reference brightness range maximum value (ReferYH) and the reference brightness range maximum value of the extended brightness range (ReferYoH) from the microcomputer ) Is calculated, the brightness range is improved for Y_ch, and the result is output to the section selector 189.

The section selector 189 corresponds to section information received from the section comparator 181 among signals received from each of the first section calculator 183, the second section calculator 185, and the third section calculator 187. Select one signal to output a brightness signal (Y1) of the extended brightness range to the brightness controller 190.

The brightness range enhancer 180 of FIG. 21B includes a brightness parameter calculator 145, a section comparator 181, and a section brightness signal calculator 182. The section brightness signal calculator 182 is a first section calculator. 183, a second section calculator 185, and a third section calculator 187. Since it is similar to the apparatus shown in Fig. 21A, only the characteristic parts will be described below.

The section comparing unit 181 outputs section information to each of the first section calculating unit 183, the second section calculating section 185, and the third section calculating section 187 to enable only the output of the section calculating section corresponding to the section. enable) to output it, and the other section calculation unit is disabled. Therefore, the brightness signal Y1 having an extended brightness range is output to the brightness controller 190.

FIG. 22 is a diagram illustrating a detailed configuration of the brightness controller 190 illustrated in FIG. 19 and includes a reference value calculator 20, a brightness enhancement ratio divider 140, and an RGB multiplier 150. The brightness controller 190 shown in FIG. 22 is similar to the brightness controller shown in FIG. 4, except for the brightness parameter calculator 145, and the operations of the remaining components are the same. Therefore, only the characteristic parts will be described below.

Compared with the apparatus of FIG. 4, the difference is that the reference value calculator 20 of FIG. 22 is an output of the brightness range enhancer 180 instead of receiving the brightness parameter Y_ch from the brightness parameter calculator 145 as shown in FIG. 4. The reference brightness value Ref_Y is calculated by receiving a signal Y1 having an improved brightness range. By using the signal Y1 having an improved brightness range as the variable x of the function F () represented by Equation 3, the image brightness may be adaptively controlled according to the brightness range of the image.

23 is a flowchart illustrating an adaptive image brightness control method according to the brightness range or brightness range and brightness degree of an image according to an embodiment of the present invention.

A method of expressing the brightness range Y_DR of an image is as follows.

Here, Y_high means the maximum value among the brightness values of the image, Y_low means the minimum value among the brightness values of the image. The Y_high and the Y_low may be set to brightness values at the top 10% and the bottom 10% positions based on the total number of pixels, respectively.

On the other hand, a large contrast of an image is equivalent to a large Y_DR value.

The reference value calculator 20 shown in FIGS. 4 and 22 calculates the reference brightness value Ref_Y represented by Equations 2 and 3 and is used to improve the brightness of the input image. At this time, instead of the brightness parameter (Y_ch) of the current input image used as a variable of the function F (), if the brightness value (Y1) with the extended brightness range is used, the output image with improved brightness can be obtained according to the brightness range of the input image. have. In addition, by using the brightness enhancement parameter (Y_Gval) to calculate the brightness in the method as shown in Figs. 16 to 18, the adaptive image brightness control according to the brightness degree of the image together with the adaptive image brightness control according to the brightness range It also becomes possible.

An adaptive image brightness control method according to the brightness range or the brightness range and the brightness degree of the image will be described with reference to FIGS. 19 to 23.

First, an image of a frame unit is input to the parameter setting unit 170, the brightness range enhancement unit 180, and the brightness control unit 190 (operation 800).

The average brightness calculator 163 calculates an average brightness Y_mean of one frame image (operation 810). The average brightness Y_mean can be obtained by the steps as shown in FIG. 17 described above.

In operation 820, the parameter calculator 165 calculates the brightness enhancement parameter Y_Gval from the average brightness Y_mean of the image. The brightness enhancement parameter Y_Gval may be obtained by the steps as shown in FIG. 18 described above.

The brightness minimum value calculator 174 and the brightness maximum value calculator 176 calculate the minimum brightness value Y_low and the maximum value Y_high of the image, respectively (step 830). Brightness range minimum value (Y_low) and maximum value (Y_high) may be the highest value and the smallest value of the brightness value of the image, respectively, in the present embodiment, when viewed in the brightness histogram, the brightness is the top 10 based on the total number of pixels, respectively Set the brightness value at the% position and the brightness value at the lower 10% position.

The second parameter calculator 175 and the third parameter calculator 177 calculate the minimum applied value (AppYL) and the maximum value (AppYH), respectively, in operation 840. In order to extend the brightness range of an image, a reference of the brightness range is required. For this, a reference brightness range maximum value (ReferYH) and a reference brightness range minimum value (ReferYL) are used. When the brightness range values Y_high and Y_low are calculated for the input image, the method of determining the increase amount of the brightness range is as follows.

Here, AppYL and AppYH are the minimum and maximum values of the extended brightness range to be applied to the actual image, respectively, and LowScale and HighScale are parameters controlling the extent of brightness range extension, respectively. As an example of the parameter value, both the LowScale and HighScale values are 0.3, ReferYL = 1, and ReferYH = 255.

For each pixel input from the brightness range enhancing unit 850, a signal Y1 having an extended brightness range is calculated for each section to which the brightness parameter belongs (S850).

In operation 860, the brightness controller 190 calculates values of brightness enhancement for each pixel using the brightness enhancement parameter Y_Gval. This step can be obtained by the steps as shown in Figs.

Steps 850 and 860 are repeated until all the pixels in the input one frame image are processed (step 870).

FIG. 24 is a flowchart for describing the operation 850 of FIG. 23 in more detail. It demonstrates with reference to FIG. 19, FIG. 21A, FIG. 21B, and FIG.

First, the brightness parameter Y_ch, the applied brightness minimum value AppYL and the applied brightness maximum parameter AppYH are input to the section comparator 181 (step 851).

In operation 852, it is determined whether the brightness parameter Y_ch is smaller than the applied brightness minimum value parameter AppYL.

When the brightness parameter Y_ch is smaller than the applied brightness minimum value AppYL, the first interval calculator 183 obtains the brightness signal Y1 having an extended brightness range by Equation 22 (step 853).

If the brightness parameter Y_ch is not smaller than the applied brightness minimum value AppYL, it is determined whether the brightness parameter Y_ch is greater than the applied brightness maximum value parameter AppYH (step 854).

When the brightness parameter Y_ch is not greater than the applied brightness maximum value parameter AppYH, the second period calculator 185 obtains the brightness signal Y1 having the extended brightness range by Equation 23 (step 855).

When the brightness parameter Y_ch is larger than the applied brightness maximum value parameter AppYH, the third section calculating unit 187 obtains the brightness signal Y1 having an extended brightness range by Equation 24 (step 856).

After each of steps 853 and 856 to 856, the brightness signal Y1 having an extended brightness range is output to the brightness controller 190 (step 857).

On the other hand, the present invention can also be embodied as computer readable codes on a computer readable recording medium. The computer-readable recording medium includes all kinds of recording devices in which data that can be read by a computer system is stored. Examples of computer-readable recording media include ROM, RAM, CD-ROM, magnetic tape, floppy disks, optical data storage devices, and the like, and may also be implemented in the form of a carrier wave (for example, transmission over the Internet). It includes being. The computer readable recording medium can also be distributed over network coupled computer systems so that the computer readable code is stored and executed in a distributed fashion.

Although the present invention has been described with reference to one embodiment shown in the drawings, this is merely exemplary, and those skilled in the art will understand that various modifications and equivalent other embodiments are possible therefrom. Therefore, the true technical protection scope of the present invention will be defined by the technical spirit of the appended claims.

As described above, the method for controlling the brightness of an image and the apparatus for controlling the brightness of an image according to the present invention have the effect of maintaining the original color while increasing the brightness of the entire or partial image. In addition, the adaptive brightness control method and apparatus according to the brightness of the image according to the present invention has the effect of maintaining the original color while adaptively improving the brightness according to the brightness of the image in the entire image or a portion of the image. In addition, the adaptive brightness control method and apparatus according to the brightness range and / or the brightness degree of the image according to the present invention adaptively according to the brightness range and / or brightness degree of the image in the entire image or a portion of the image adaptively brightness range and / or It has the effect of maintaining the original color while improving the brightness.

Claims (58)

delete delete delete A brightness difference calculator for outputting a difference in brightness with respect to the reference brightness and a predetermined input signal; A brightness increase amount calculator configured to output a brightness increase amount corresponding to the brightness difference; A brightness increase amount calculator for each element outputting a brightness increase amount of each of the elements constituting the predetermined input signal corresponding to the brightness increase amount; And And an operation unit configured to output an output signal of which brightness is increased from the input signal in response to the predetermined input signal and an output signal of the element brightness increase calculator for each element. The method of claim 4, wherein the brightness increase amount calculation unit for each element And multiplying the unit vector of each element constituting the predetermined input signal by the brightness increase amount and outputting an increase amount of each of the elements. A brightness calculator for outputting brightness corresponding to a predetermined input signal; A reference value calculator for outputting a reference brightness corresponding to the brightness; A brightness increase amount calculator configured to output a brightness increase amount corresponding to the difference between the reference brightness and the brightness; An increase amount calculation unit for each component calculating and outputting an increase amount of each of the components constituting the predetermined input signal from the increase amount of brightness; And And an operation unit configured to output an output signal having increased brightness by adding each component constituting the predetermined input signal and an output signal of the increment amount calculation unit for each component. The method of claim 6, wherein the component increasing amount calculating unit And multiplying the unit vector of each element constituting the predetermined input signal by the brightness increase amount and outputting an increase amount of each of the elements. A maximum component calculating unit outputting a value of an element having a maximum value among elements constituting a predetermined input signal; A reference value calculator for outputting a reference brightness value corresponding to the output value; A brightness difference calculator for outputting a brightness difference between the reference brightness and the element having the maximum value; A brightness increase amount calculator configured to output a brightness increase amount corresponding to the brightness difference in response to the brightness difference and the elements constituting the input signal; An RGB increase amount calculation circuit for outputting a brightness increase amount for each element constituting the input signal in response to the elements constituting the input signal and the brightness increase amount; And And a multiplication calculation unit for adding each element constituting an input signal and an increase amount of brightness for each element. A brightness parameter calculator for outputting a brightness parameter corresponding to an input video signal composed of a plurality of elements; A reference value calculator for outputting a reference brightness value corresponding to the output value; A brightness enhancement ratio dividing unit dividing the reference brightness value by an output value of the maximum component calculating unit to output a brightness enhancement ratio; And And an element multiplier for multiplying and outputting each of the elements constituting the input image signal to the brightness enhancement ratio. The method of claim 9, wherein the brightness parameter calculator, And a brightness parameter is a value of an element having a maximum value among the elements constituting the input image signal. The method of claim 9, wherein the reference value calculator, And a reference brightness value corresponding to the output value by using a plurality of reference brightness value functions corresponding to the input control signal. A brightness enhancement parameter setting unit for outputting a brightness enhancement parameter for determining a degree of increase or decrease of image brightness in response to an input video signal composed of a plurality of elements and a predetermined control signal; And And a brightness controller configured to control the brightness of the image in response to the brightness enhancement parameter and the input signal. The apparatus of claim 12, wherein the adaptive image brightness control device comprises: And an RGB signal converting unit converting the input image signal into a brightness signal if the input image signal is an RGB type signal. The method of claim 12, wherein the brightness control unit, A brightness parameter calculator for outputting a brightness parameter corresponding to the input image signal; A reference value calculator for outputting a reference brightness value corresponding to the output value; A brightness enhancement ratio dividing unit dividing the reference brightness value by an output value of the maximum component calculating unit to output a brightness enhancement ratio; And And an element multiplier for multiplying and outputting each of the elements constituting the input image signal to the brightness enhancement ratio. The method of claim 14, wherein the brightness parameter calculator, And a brightness parameter is a value of an element having a maximum value among the elements constituting the input image signal. The method of claim 12, wherein the brightness enhancement parameter setting unit, An average brightness calculator for calculating and outputting an average brightness of the input image signal; And And a parameter calculating unit configured to calculate and output a brightness enhancement parameter in response to the average brightness and a predetermined control signal. The method of claim 16, wherein the parameter calculator, And an brightness enhancement parameter is calculated by comparing the average brightness with a predetermined reference brightness. A parameter setting unit for outputting a maximum value and a minimum value of the brightness of the input image signal and a maximum value and the minimum value of the extended brightness in response to an input video signal composed of a plurality of elements and a predetermined control signal; And Extended brightness of the input video signal in response to the input video signal, the plurality of output values of the parameter setting unit, a maximum reference value and a minimum reference value of brightness of a predetermined video signal, and a maximum reference value and a minimum reference value of extended brightness. Adaptive image brightness control device according to the brightness range of the image, characterized in that it comprises a brightness range improving unit for outputting a signal. The method of claim 18, wherein the brightness range enhancement unit, A brightness parameter calculator for outputting a brightness parameter corresponding to the input image signal; A section comparator comparing the brightness parameter with a maximum value and a minimum value of the brightness of the input image signal to determine which section the brightness parameter belongs to and output section information; And And a brightness signal calculator for each section outputting a brightness parameter of which the brightness range is extended in response to the section information and the brightness parameter. The method of claim 18, wherein the brightness range enhancement unit, A brightness parameter calculator for outputting a brightness parameter corresponding to the input image signal; A section comparator comparing the brightness parameter with a maximum value and a minimum value of the brightness of the input image signal to determine which section the brightness parameter belongs to and output section information; A brightness signal calculator for each section outputting a plurality of brightness parameters having a brightness range extended for each section in response to the brightness parameter; And And a section selector configured to receive a plurality of brightness parameters having the extended brightness range and the section information, select a brightness parameter corresponding to the section information, and output a brightness signal having the extended brightness range. Adaptive image brightness control device according to image brightness range. The method of claim 19 or 20, wherein the brightness parameter calculator, And a brightness parameter is a value of an element having a maximum value among the elements constituting the input image signal. The apparatus of claim 19 or 20, wherein the adaptive image brightness control device comprises: And a brightness controller for controlling the brightness of the image in response to the brightness parameter, the brightness signal with the extended brightness range, and the input signal. The method of claim 22, wherein the brightness control unit, A reference value calculator for outputting a reference brightness value corresponding to the brightness signal of which the brightness range is extended; A brightness enhancement ratio dividing unit dividing the reference brightness value by the brightness parameter to output a brightness enhancement ratio; And And an element multiplier configured to multiply each of the elements constituting the input image signal by the brightness enhancement ratio and output the multiplier. The method of claim 22, wherein the parameter setting unit, In response to the signal included in the input image signal and the predetermined control signal, adaptive image brightness control device according to the brightness range of the image, characterized in that for calculating the brightness enhancement parameter for determining the degree of increase or decrease of the image brightness; . The method of claim 24, wherein the parameter setting unit, An average brightness calculator for calculating and outputting an average brightness of the input image signal; And Adaptive image according to the brightness range of the image further comprises a parameter calculating unit for calculating and outputting the brightness enhancement parameter in response to the average brightness and the signal included in the predetermined control signal; Brightness control. The method of claim 25, wherein the parameter calculator, And calculating the brightness enhancement parameter by comparing the average brightness with a predetermined reference brightness. The method of claim 25 or 26, wherein the parameter setting unit, And an RGB signal converting unit converting the input image signal into a brightness signal when the input image signal is an RGB type signal. delete delete delete In the image brightness control method, Outputting a difference between the reference brightness and the brightness of the predetermined input signal; Outputting an increase in brightness corresponding to the difference in brightness; Outputting a brightness increase amount of each element constituting the predetermined input signal in correspondence with the brightness increase amount; And And outputting an output signal of which brightness is increased from the input signal in response to the predetermined input signal and an output signal of the brightness increase amount calculator for each element. In the image brightness control method, Outputting brightness corresponding to a predetermined input signal; Outputting a reference brightness corresponding to the brightness: Outputting a brightness increase amount corresponding to the difference between the reference brightness and the brightness; Calculating and outputting a brightness increase amount of each component constituting the predetermined input signal from the brightness increase amount; And And outputting an output signal having increased brightness by adding each component constituting the predetermined input signal and an output signal of the increase amount calculating unit for each component. In the image brightness control method, Outputting brightness for an element having a maximum value among elements constituting a predetermined input signal; Outputting a reference brightness corresponding to the brightness for the element having the maximum value; Outputting a difference in brightness for the element having the reference brightness and the maximum value; Outputting a brightness increase amount corresponding to the brightness difference in response to the brightness difference and the elements constituting the input signal; Outputting a brightness increase amount for each element constituting the input signal in response to the elements constituting the input signal and the brightness increase amount; And And adding each element constituting an input signal and an increase amount of brightness for each element. A brightness parameter calculating step of outputting a brightness parameter corresponding to an input video signal composed of a plurality of elements; A reference value calculating step of outputting a reference brightness value corresponding to the output value; Dividing the reference brightness value by an output value of the maximum component calculator to output a brightness enhancement ratio; And And an element multiplication step of multiplying and outputting each of the elements constituting the input image signal to the brightness enhancement ratio. The method of claim 34, wherein the brightness parameter calculation step, And a brightness parameter is a value of an element having a maximum value among the elements constituting the input image signal. The method of claim 34, wherein the reference value calculation step, And a reference brightness value corresponding to the output value by using a plurality of reference brightness value functions corresponding to the input control signal. A brightness enhancement parameter setting step of outputting a brightness enhancement parameter for determining a degree of increase or decrease of image brightness in response to an input video signal composed of a plurality of elements and a predetermined control signal; And And a brightness control step of controlling the brightness of the image in response to the brightness enhancement parameter and the input signal. The method of claim 37, wherein the adaptive image brightness control method comprises: And an RGB signal conversion step of converting the input image signal into a brightness signal if the input image signal is an RGB type signal. The method of claim 37, wherein the brightness control step, A brightness parameter calculating step of outputting a brightness parameter corresponding to the input video signal; A reference value calculating step of outputting a reference brightness value corresponding to the output value; Dividing the reference brightness value by an output value of the maximum component calculator to output a brightness enhancement ratio; And And an element multiplication step of multiplying each of the elements constituting the input image signal by the brightness enhancement ratio and outputting the same. The method of claim 39, wherein the brightness parameter calculation step, And a brightness parameter is a value of an element having a maximum value among the elements constituting the input image signal. The method of claim 37, wherein the setting of the brightness enhancement parameter comprises: An average brightness calculating step of calculating and outputting an average brightness of the input image signal; And And a parameter calculating step of calculating and outputting a brightness enhancement parameter in response to the average brightness and a predetermined control signal. 42. The method of claim 41 wherein the parameter calculating step comprises: And comparing the average brightness with a predetermined reference brightness to calculate the brightness enhancement parameter. A parameter setting step of outputting a maximum value and a minimum value of the brightness of the input image signal and a maximum value and the minimum value of the extended brightness in response to an input video signal composed of a plurality of elements and a predetermined control signal; And Extended brightness of the input video signal in response to the input video signal, the plurality of output values of the parameter setting unit, a maximum reference value and a minimum reference value of brightness of a predetermined video signal, and a maximum reference value and a minimum reference value of extended brightness. Adaptive brightness control method according to the brightness range of the image, characterized in that it comprises a brightness range improving step of outputting a signal. The method of claim 43, wherein the brightness range improving step, A brightness parameter calculating step of outputting a brightness parameter corresponding to the input video signal; A section comparison step of outputting section information by comparing the brightness parameter with a maximum value and a minimum value of the brightness of the input image signal to determine which section the brightness parameter belongs to; And And a brightness signal calculation step for outputting a brightness parameter of which the brightness range is extended in response to the section information and the brightness parameter. The method of claim 43, wherein the brightness range improving step, A brightness parameter calculating step of outputting a brightness parameter corresponding to the input video signal; A section comparison step of comparing section of the brightness parameter with a maximum value and a minimum value of the brightness of the input image signal to determine which section the brightness parameter belongs to and output section information; A brightness signal calculation step for outputting a plurality of brightness parameters having a brightness range extended for each section in response to the brightness parameter; And And a section selecting step of receiving a plurality of brightness parameters of the extended brightness range and the section information, selecting a brightness parameter corresponding to the section information, and outputting a brightness signal having the extended brightness range. Adaptive image brightness control method according to the brightness range of the image. 46. The method of claim 44 or 45, wherein the brightness parameter calculating step, Adaptive brightness control method according to the brightness range of the image, characterized in that the value of the element having the maximum value among the elements constituting the input image signal as the brightness parameter. 46. The method of claim 44 or 45, wherein the adaptive image brightness control method And a brightness control step of controlling the brightness of the image in response to the brightness parameter, the brightness signal of which the brightness range is expanded, and the input signal. The method of claim 47, wherein the brightness control step, A reference value calculating step of outputting a reference brightness value corresponding to the brightness signal of which the brightness range is extended; Dividing the reference brightness value by the brightness parameter to output a brightness enhancement ratio; And And an element-specific multiplication step of multiplying and outputting each of the elements constituting the input image signal to the brightness enhancement ratio. The method of claim 47, wherein the parameter setting step, In response to the signal included in the input image signal and the predetermined control signal, adaptive brightness control method according to the brightness range of the image, characterized in that for calculating the brightness enhancement parameter for determining the degree of increase or decrease of the image brightness; . The method of claim 49, wherein the parameter setting step, An average brightness calculating step of calculating and outputting an average brightness of the input image signal; And And a parameter calculating step of calculating and outputting a brightness enhancement parameter in response to the average brightness and the signal included in the predetermined control signal to output the brightness enhancement parameter. Image brightness control method. The method of claim 50, wherein the parameter calculation step, And calculating the brightness enhancement parameter by comparing the average brightness with a predetermined reference brightness. The method of claim 50 or 51, wherein the parameter setting step, And an RGB signal converting step of converting the input image signal into a brightness signal if the input image signal is an RGB type signal. delete In the image brightness control method, Outputting a difference between the reference brightness and the brightness of the predetermined input signal; Outputting an increase in brightness corresponding to the difference in brightness; Outputting a brightness increase amount of each element constituting the predetermined input signal in correspondence with the brightness increase amount; And And outputting an output signal of which brightness is increased from the input signal in response to the predetermined input signal and an output signal of the brightness increase amount calculator for each element. Computer-readable recording media. In the image brightness control method, Outputting brightness for an element having a maximum value among elements constituting a predetermined input signal; Outputting a reference brightness corresponding to the brightness for the element having the maximum value; Outputting a difference in brightness for the element having the reference brightness and the maximum value; Outputting a brightness increase amount corresponding to the brightness difference in response to the brightness difference and the elements constituting the input signal; Outputting a brightness increase amount for each element constituting the input signal in response to the elements constituting the input signal and the brightness increase amount; And And adding each element constituting the input signal and an increase amount of the brightness for each element. A computer-readable recording medium having recorded thereon a program for realizing an image brightness control method. A brightness parameter calculating step of outputting a brightness parameter corresponding to an input video signal composed of a plurality of elements; A reference value calculating step of outputting a reference brightness value corresponding to the output value; Dividing the reference brightness value by an output value of the maximum component calculator to output a brightness enhancement ratio; And And a multiplication step for each element constituting the input image signal by multiplying and outputting the brightness enhancement ratio. A brightness enhancement parameter setting step of outputting a brightness enhancement parameter for determining a degree of increase or decrease of image brightness in response to an input video signal composed of a plurality of elements and a predetermined control signal; And And a brightness control step of controlling the brightness of the image in response to the brightness enhancement parameter and the input signal. A program for realizing an adaptive image brightness control method according to the brightness level of the image can be read by a computer. Recording media. A parameter setting step of outputting a maximum value and a minimum value of the brightness of the input image signal and a maximum value and the minimum value of the extended brightness in response to an input video signal composed of a plurality of elements and a predetermined control signal; And Extended brightness of the input video signal in response to the input video signal, the plurality of output values of the parameter setting unit, a maximum reference value and a minimum reference value of brightness of a predetermined video signal, and a maximum reference value and a minimum reference value of extended brightness. And a brightness range enhancing step of outputting a signal, wherein the computer-readable recording medium has recorded a program for realizing an adaptive image brightness control method according to the brightness range of the image.