Patent Publication Number: US-11665327-B2

Title: Image processing apparatus

Description:
CROSS REFERENCE TO RELATED APPLICATIONS 
     This application is the National Phase of PCT/KR2019/014766 filed on Nov. 1, 2019, which is hereby expressly incorporated by reference into the present application. 
     TECHNICAL FIELD 
     The following description relates to an image processing apparatus. 
     BACKGROUND ART 
     An image display apparatus is an apparatus having a function of providing images that users view. For example, the image display apparatus may include a monitor, a television (TV), and the like. 
     The image display apparatus may be connected by wire/wirelessly to an external device to display various images, received from the external device, on a screen. For example, the image display apparatus first stores images received from the external device and may output the stored images according to a screen size of the image display apparatus, the number of frames displayed per second, and the like. 
     Meanwhile, a dark area in an image has lower luminance compared to a bright area, such that a boundary between objects or a boundary between a background and an object is not clear, thereby causing a problem in that a user may not clearly recognize the dark area. 
     In order to solve the problem, an existing image display apparatus provides a function of adjusting the entire luminance according to a user input, or adjusting the gamma of the entire screen, or the like. Here, the gamma may indicate a level of correlation between a signal input to a display and luminance of an image displayed on a screen. 
     However, increasing the luminance of the entire screen or reducing a gamma value to brighten a dark area in an image leads to an excessive increase in the luminance of a bright area as well, thereby causing a problem in that a boundary between objects or a boundary between a background or an object becomes unclear. 
     In addition, appropriate luminance varies according to the type of image, such that in an existing method, it is inconvenient for users to separately change each setting according to the type of image, and particularly, if there is a large difference in luminance between frames of an image displayed on a screen, such as a game image, it is impossible practically for users to separately change each setting. 
     DISCLOSURE OF INVENTION 
     Technical Problem 
     It is an object of the present disclosure to solve the above and other problems. 
     It is another object of the present disclosure to provide an image processing apparatus capable of dynamically changing criteria for determining an output level of a plurality of pixels included in a display panel, thereby improving visibility of an image. 
     Technical Solution 
     In accordance with an embodiment of the present disclosure, the above and other objects can be accomplished by providing an image processing apparatus including: a display having a plurality of pixels; and a controller, wherein the controller: calculates an average luminance value of a first frame of an image based on RGB data corresponding to the image; sets a criterion for determining an output level of the plurality of pixels according to the average luminance value of the first frame; controls the display to output a first frame group, including the first frame, according to the set criterion; calculates an average luminance value of a second frame of the image according to a predetermined cycle; resets a criterion for determining the output level of the plurality of pixels according to the average luminance value of the second frame; and controls the display to output a second frame group, including the second frame, according to the reset criterion. 
     In addition, according to an embodiment of the present disclosure, a last frame of the first frame group may be a frame output immediately before the second frame is output. 
     In addition, according to an embodiment of the present disclosure, the controller: may extract RGB data corresponding to any one of the plurality of frames of the image, to calculate an average luminance value of the any one frame; may calculate a logarithm value of the average luminance value of the any one frame; and may determine a gamma curve, corresponding to the calculated logarithm value, as the criterion for determining the output level of the plurality of pixels, the output level associated with output of a frame group including the any one frame. 
     In addition, according to an embodiment of the present disclosure, as the calculated logarithm value decreases, a difference between the gamma curve, corresponding to the calculated logarithm value, and a reference gamma curve may increase in a low gray level area. 
     In addition, according to an embodiment of the present disclosure, the controller: may convert the RGB data, corresponding to the any one frame, into HSV data related to Hue, Saturation, and Value; and may calculate the average luminance value of the any one frame based on the HSV data. 
     In addition, according to an embodiment of the present disclosure, the controller may calculate the average luminance value of the any one frame based on an average value of the data related to Value, among the HSV data. 
     In addition, according to an embodiment of the present disclosure, the controller: may extract RGB data for a plurality of specific pixels from the RGB data corresponding to the any one frame based on a predetermined criterion; may convert the RGB data for the plurality of specific pixels into HSV data for the plurality of specific pixels; and may calculate the average luminance value of the any one frame based on the HSV data for the plurality of specific pixels. 
     In addition, according to an embodiment of the present disclosure, the predetermined criterion for extracting the RGB data for the plurality of specific pixels from the RGB data corresponding to the any one frame may be determined according to a number of the plurality of pixels. 
     In addition, according to an embodiment of the present disclosure, the controller of the image processing apparatus: may calculate a logarithm value of the average luminance value of the any one frame; and may determine a gamma curve, corresponding to the calculated logarithm value, as the criterion for determining the output level of the plurality of pixels, the output level associated with output of a frame group including the any one frame. 
     Meanwhile, in accordance with another embodiment of the present disclosure, the above and other objects can be accomplished by providing an image processing apparatus including: an interface circuit configured to transmit and receive data with an external device; and a controller, wherein the controller: transmits RGB data, corresponding to an image, to the external device through the interface circuit; calculates an average luminance value of a first frame of the image based on the RGB data; determines a criterion for determining an output level, associated with output of a first frame group including the first frame, according to the average luminance value of the first frame; transmits data on the determined criterion to the external device through the interface circuit; calculates an average luminance value of a second frame of the image according to a predetermined cycle; redetermines a criterion for determining an output level, associated with output of a second frame group including the second frame, according to the average luminance value of the second frame; and transmits data on the redetermined criterion to the external device through the interface circuit. 
     In addition, according to another embodiment of the present disclosure, a last frame of the first frame group may be a frame output immediately before the second frame is output. 
     In addition, according to another embodiment of the present disclosure, the controller of the image processing apparatus: may extract RGB data corresponding to any one of the plurality of frames of the image, to calculate an average luminance value of the any one frame; may calculate a logarithm value of the average luminance value of the any one frame; may determine a criterion for determining an output level, associated with output of a frame group including the any one frame, based on the calculated logarithm value; and may transmit data on the criterion to the external device through the interface circuit. 
     In addition, according to another embodiment of the present disclosure, the controller of the image processing apparatus: may convert the RGB data, corresponding to the any one frame, into HSV data related to Hue, Saturation, and Value; and may calculate the average luminance value of the any one frame based on the HSV data. 
     In addition, according to another embodiment of the present disclosure, the controller of the image processing apparatus may calculate the average luminance value of the any one frame based on an average value of the data related to Value, among the HSV data. 
     In addition, according to another embodiment of the present disclosure, the controller of the image processing apparatus: may extract data for a plurality of specific pixels from the data related to Value based on a predetermined criterion; and may calculate an average value of the data for the plurality of specific pixels as the average value of the data related to Value. 
     In addition, according to another embodiment of the present disclosure, the predetermined criterion for extracting the RGB data for the plurality of specific pixels from the RGB data corresponding to the any one frame may be determined according to a number of the plurality of pixels. 
     Advantageous Effects 
     The image processing apparatus according to the present disclosure has the following effects. 
     According to at least one of the embodiments of the present disclosure, by dynamically changing criteria for determining an output level of a plurality of pixels included in a display panel based on luminance of an image, the image may be displayed more clearly. 
     According to at least one of the embodiments of the present disclosure, by calculating average luminance values of image frames according to a predetermined cycle, the criterion for determining the output level of the plurality of pixels may be changed dynamically, such that an image may be displayed clearly without a separate user input even when there is a large difference in luminance between the image frames. 
     Further scope of applicability of the present disclosure will become apparent from the detailed description given hereinafter. However, it should be understood that the detailed description and specific examples, while indicating preferred embodiments of the present disclosure, are given by illustration only, since various changes and modifications within the spirit and scope of the present disclosure will become apparent to those skilled in the art from this detailed description. 
    
    
     
       DESCRIPTION OF DRAWINGS 
         FIG.  1    is a diagram illustrating a connection state between an image processing apparatus and an external device according to an embodiment of the present disclosure. 
         FIG.  2    is an internal block diagram illustrating the image processing apparatus of  FIG.  1   . 
         FIG.  3    is an internal block diagram illustrating a controller of  FIG.  2   . 
         FIG.  4    is an internal block diagram illustrating an image processing apparatus according to another embodiment of the present disclosure. 
         FIG.  5    is a flowchart illustrating a method of operating an image processing apparatus according to an embodiment of the present disclosure. 
         FIG.  6    is a flowchart illustrating a method of operating an image processing apparatus according to an embodiment of the present disclosure. 
         FIGS.  7  to  10 B  are diagrams referred to in the description of operation of an image processing apparatus according to various embodiments of the present disclosure. 
         FIG.  11    is a flowchart illustrating a method of operating an image processing apparatus according to an embodiment of the present disclosure. 
     
    
    
     BEST MODE FOR CARRYING OUT THE INVENTION 
     Hereinafter, the present disclosure will be described in detail with reference to the accompanying drawings. In order to clearly and briefly describe the present disclosure, components that are irrelevant to the description will be omitted in the drawings. The same reference numerals are used throughout the drawings to designate the same or similar components, and a redundant description thereof will be omitted. 
     Terms “module” and “unit” for elements used in the following description are given simply in view of the ease of the description, and do not carry any important meaning or role. Therefore, the “module” and the “part” may be used interchangeably. 
     It should be understood that the terms “comprise”, ‘include”, “have”, etc. when used in this specification, specify the presence of stated features, integers, steps, operations, elements, components, or combinations thereof but do not preclude the presence or addition of one or more other features, integers, steps, operations, elements, components, or combinations thereof. 
     In addition, it will be understood that, although the terms first, second, etc., may be used herein to describe various elements, these elements should not be limited by these terms. These terms are only used to distinguish one element from another. 
       FIG.  1    is a diagram illustrating a connection state between an image processing apparatus and external devices according to an embodiment of the present disclosure. 
     Referring to  FIG.  1   , an image processing apparatus  100  may be an apparatus for processing and outputting images. In the following description, an image processing apparatus and an image display apparatus may be used interchangeably. 
     The image processing apparatus  100  may include a TV, a notebook computer, a monitor, a projector, a digital broadcasting terminal, a cellular phone, a smartphone, a tablet PC, etc., but is not particularly limited as long as the apparatus may output a screen corresponding to an image signal. 
     Meanwhile, the image processing apparatus  100  may output images received from an image providing device  300 . For example, the image processing device  100  may store images received from the image providing device  300 , and may output the stored images according to a screen size of the image processing apparatus  100 , the number of frames displayed per second, and the like. 
     The image providing device  300  may be a computer and the like, but is not particularly limited as long as the device may transmit a signal including RGB data corresponding to an image. 
     A remote control device  200  may be connected by wire and/or wirelessly to the image processing apparatus  100 , to provide various control signals to the image processing apparatus  100 . In this case, the remote control device  200  may include a device for establishing a wired or wireless network with the image processing apparatus  100 , to transmit various control signals to the image processing apparatus  100  or to receive from the image processing apparatus  100  signals related to various operations processed by the image processing apparatus  100 , through the established network. 
     For example, various input devices, such as a mouse  200   a , a keyboard  200   b , a space remote controller  200   c , a track ball, a joystick, etc., may be used as the remote control device  200 . The remote control device  200  may be referred to as an external device, and the external device and the remote control device may be used interchangeably in the following description, if necessary. 
     The image processing device  100  may be connected to only a single remote control device  200 , or may be simultaneously connected to two or more remote control devices  200  to change an object displayed on a screen or to control a screen status based on control signals provided by the respective remote control devices  200 . 
       FIG.  2    is an internal block diagram illustrating the image processing apparatus of  FIG.  1   . 
     Referring to  FIG.  2   , the image processing apparatus  100  may include a broadcast receiver  105 , an external device interface  130 , a network interface  135 , a storage  140 , a user input interface  150 , an input unit  160 , a controller  170 , a display  180 , an audio output unit  185 , and/or a power supply unit  190 . 
     The broadcast receiver  105  may include a tuner  110  and a demodulator  120 . 
     Meanwhile, unlike the drawing, the image processing apparatus  100  may include only the broadcast receiver  105  and the external device interface  130 , among the broadcast receiver  105 , the external device interface  130 , and the network interface  135 . That is, the image processing apparatus  100  may not include the network interface  135 . 
     The tuner  110  may select a broadcast signal corresponding to a channel selected by a user or broadcast signals corresponding to all prestored channels from among Radio Frequency (RF) broadcast signals received through an antenna (not shown). The tuner  110  may convert a selected broadcast signal into an intermediate frequency (IF) signal or a baseband video or audio signal. 
     For example, if the selected RF broadcast signal is a digital broadcast signal, the tuner  110  may convert the selected RF broadcast signal into a digital IF signal (DIF), and if the selected RF broadcast signal is an analog broadcast signal, the tuner  100  may convert the selected RF broadcast signal into an analog baseband video or audio signal CVBS/SIF. That is, the tuner  110  may process digital broadcast signals or analog broadcast signals. The analog baseband video or audio signal CVBS/SIF output from the tuner  110  may be directly input to the controller  170 . 
     Meanwhile, the tuner  110  may sequentially select RF broadcast signals of all the broadcast channels stored through a channel memory function from among the RF broadcast signals received through the antenna and may convert the selected broadcast signals into IF signals or baseband video or audio signals. 
     Meanwhile, the tuner  110  may include a plurality of tuners for receiving broadcast signals of a plurality of channels. Alternatively, the tuner  110  may be a single tuner that simultaneously receives broadcast signals of a plurality of channels. 
     The demodulator  120  may receive a digital IF signal DIF converted by the tuner  110  and may demodulate the digital IF signal. 
     Upon performing demodulation and channel decoding, the demodulator  120  may output a stream signal TS. In this case, the stream signal may be a multiplexed video signal, audio signal or data signal. 
     The stream signal output from the demodulator  120  may be input to the controller  170 . Upon performing demultiplexing, video/audio signal processing, etc., the controller  170  may output an image to the display  180  and may output sound to the audio output unit  185 . 
     The external device interface  130  may transmit or receive data to or from a connected external device (not shown), e.g., the image providing device  300  illustrated in  FIG.  1   . To this end, the external device interface  130  may include an A/V input/output unit (not shown). 
     The external device interface  130  may be connected by wire/wirelessly to external devices, such as a digital versatile disc (DVD) player, a Blu-ray player, a game console, a camera, a camcorder, a computer (laptop), a set-top box, etc., and may perform input/output operations for external devices. 
     In addition, the external device interface  130  may establish a communication network with various remote control devices  200  as illustrated in  FIG.  1   , and may receive control signals related to operation of the image processing apparatus  100  or transmit data related to operation of the image processing apparatus  100 , through the established communication network. 
     The A/V input/output unit may receive video and audio signals of an external device. 
     The external device interface  130  may include a wireless communication unit (not shown) for short-range wireless communication with other electronic devices. 
     Through the wireless communication unit (not shown), the external device interface  130  may exchange data with an adjacent mobile terminal. Particularly, the external device interface  130  may receive, from the mobile terminal, device information, running application information, application images, and the like in a mirroring mode. 
     The network interface  135  may provide an interface for connecting the image processing apparatus  100  to a wired/wireless network including an Internet network. For example, the network interface  135  may receive content or data provided by the Internet, a content provider or a network operator through the network. 
     Meanwhile, the network interface  135  may include a communication module (not shown) for communication with a wired/wireless network. 
     The storage  140  may store programs for processing and controlling each signal within the controller  180 , and may store signal-processed video, audio or data signals. 
     For example, the storage  140  may store applications designed to perform various operations which may be processed by the controller  170 , and in response to a request from the controller  170 , the storage  140  may selectively provide some of the stored applications. 
     The programs and the like stored in the storage  140  are not particularly limited, as long as the programs may be executed by the controller  170 . 
     The storage  140  may also perform the function of temporarily storing video, audio or data signals received from an external device through the external device interface  130 . 
     The storage  140  may store information on predetermined broadcast channels through a channel memory function. 
     While  FIG.  2    illustrates an example in which the storage  140  is provided separately from the controller  170 , the scope of the present disclosure is not limited thereto, and the storage  140  may be included in the controller  170 . 
     The user input interface  150  may transmit a signal, input by a user, to the controller  170  or may transmit a signal, input from the controller  170 , to the user. 
     For example, the user input interface  150  may transmit/receive a user input signal, such as power on/off, channel selection, screen setup, etc., to/from a remote control device  250 , and may transmit a user input signal input through a local key (not shown), such as a power key, a channel key, a volume key, or a setup value, to the controller  170 , or may transmit a user input signal, input from a sensor unit (not shown), which senses a user&#39;s gesture, to the controller  170 , or may transmit a signal from the controller  170  to the sensor unit. 
     The input unit  160  may be provided on one side of a main body of the image processing apparatus  100 . For example, the input unit  160  may include a touchpad, a physical button, and the like. 
     The input unit  160  may receive various user commands associated with the operation of the image processing apparatus  100 , and may transmit a control signal corresponding to the input command to the controller  170 . 
     The controller  170  may include at least one processor, and by using the included processor, the controller  170  may control the overall operation of the image processing apparatus  100 . Here, the processor may be a general processor such as a central processing unit (CPU). Obviously, the processor is a dedicated device, such as an ASIC, or other hardware-based processor. 
     The controller  170  may demultiplex a stream input through the tuner  110 , the demodulator  120 , the external device interface  130 , or the network interface  135 , or may process demultiplexed signals to generate and output signals for video or audio output. 
     For example, the controller  170  may receive RGB data from the image providing device  300  through the external device interface  130 . In this case, the controller  170  may process the RGB data received from the image providing device  300 , to generate an image signal for image output, and may transmit the generated image signal to the display  180 . 
     The controller  170  may perform various functions related to the image processing apparatus  100 . 
     For example, based on a user input signal input through the input unit  160 , the controller  170  may perform a function of adjusting the gamma or luminance of the entire screen of the display  180 . 
     The controller  170  may activate a dynamic screen control function. Here, the dynamic screen control function may refer to a function of dynamically changing criteria for determining an output level of a plurality of pixels included in the display  180 , according to the luminance of an image displayed through the display  180 . 
     For example, the controller  170  may activate the dynamic screen control function based on the user input signal input through the input unit  160 . Here, the criterion for determining the output level of the plurality of pixels included in the display  180  may include a gamma curve indicates the gamma based on a relationship between signal brightness and output luminance. 
     If the dynamic screen control function is activated, the controller  170  may calculate an average luminance value of any one of frames of an image, and may set a criterion for determining an output level of the plurality of pixels. Here, the frames may refer to a static image displayed on the display  180 , and frames output to the display  180  change sequentially according to the number of frames per second (FPS), thereby allowing a user to view a video. 
     In this case, the controller  170  may repeatedly perform an operation of calculating the average luminance value of any one of the plurality of frames of an image according to a predetermined cycle, so as to dynamically change the criteria for determining the output level of the plurality of pixels included in the display  180 . 
     For example, the controller  170  may calculate an average luminance value of a first frame by extracting RGB data, corresponding to the first frame, from the RGB data corresponding to the images stored in the storage  140 . 
     In this case, the controller  170  may calculate the average luminance value of the first frame by extracting a portion of the RGB data corresponding to the first frame according to a predetermined criterion, thereby reducing the computation load of the controller  170 . 
     Here, the criterion for extracting a portion of the RGB data corresponding to the first frame may be determined based on a number of pixels on a screen of the display  180 , a screen ratio of the display  180 , and the like. 
     For example, if the display  180  has a screen ratio of 16:9, with the screen having 1920 pixels in width and 1080 pixels in height, the controller  170  may extract RGB data for 128 pixels in width and 72 pixels in height from the RGB data corresponding to the first frame. 
     In this case, a separation distance between the 128 pixels in width may be the same as a separation distance between the 72 pixels in height. 
     The controller  170  may convert the RGB data corresponding to the first frame into HSV data related to Hue, Saturation, and Value. 
     For example, the controller  170  may convert the RGB data corresponding to the first frame into hue data H, saturation data S, and value data V based on the following Equations 1, 2, and 3. 
     
       
         
           
             
               
                 
                   
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     Based on the HSV data converted from the RGB data corresponding to the first frame, the controller  170  may calculate the average luminance value of the first frame. 
     In this case, the controller  170  may calculate the average luminance value of the first frame based on the value data V, among the HSV data. For example, the controller  170  may calculate an average value Vavg of the value data V as the average luminance value of the first frame. 
     Based on the average luminance value of the first frame, the controller  170  may set a criterion for determining an output level of the plurality of pixels of the display  180  for outputting the first frame. In this case, considering that a user&#39;s eyes nonlinearly sense light, the controller  170  may set the criterion for determining the output level of the plurality of pixels of the display  180  based on a logarithm value of the average luminance value of the first frame, as represented by the following Equation 4.
 
 BSV= 100−41.55 log( V avg)  [Equation 4]
 
     Herein, a Black Stabilizer Value (BSV) may refer to a value indicating a degree of adjustment of a screen to brighten a dark area in an image. In the present disclosure, the BSV is calculated over a range of values from  0  to  100  using the above Equation 4, but the present disclosure is not limited thereto, and the BSV may be calculated by various equations using a logarithm value of the average luminance value of the frames. 
     Based on the BSV of the first frame, the controller  170  may set the a criterion for determining the output level of the plurality of pixels of the display  180 . 
     The controller  170  may determine a gamma curve, corresponding to the BSV of the first frame, as a gamma curve for the first frame among a plurality of gamma curves, or may also determine the gamma curve for the first frame by adjusting a predetermined gamma curve based on the BSV of the first frame. 
     In the above Equation 4, as the average luminance value of the first frame decreases, the BSV increases. In this case, as the BSV of the first frame increases, a difference between the gamma curve for the first frame and a reference gamma curve in a low gray level area may increase. Here, the reference gamma curve may be, for example, a gamma curve having a gamma value of 2.2. 
     In other words, when the BSV increases as the average luminance value of the first frame decreases, a slope of the gamma curve for the first frame in the low gray level area may increase. 
     The output level of the plurality of pixels of the display  180  during the output of the first frame may be determined according to the gamma curve for the first frame. For example, as the BSV of the first frame increases, the output level of the pixels corresponding to the low gray level area in the first frame may also increase according to a change in the gamma curve for the first frame. 
     Meanwhile, even when the BSV of the first frame increases, an output level of the pixels corresponding to a high gray level area in the first frame may be constant. For example, as the BSV of the first frame increases, there may be a constant difference between the gamma curve for the first frame and the reference gamma curve in the high gray level area. 
     In this manner, a screen may be adjusted so that a dark area in the image may be displayed clearly, thereby improving visibility. 
     The controller  170  may control the display  180  to output the first frame according to the gamma curve for the first frame. 
     The controller  170  may control the display  180  so that a first frame group, including the first frame, may be output according to the criterion for determining the output level of the plurality of pixels, with the criterion being set based on the average luminance value of the first frame. Here, the first frame group may refer to a group of frames from the first frame to a frame output immediately before a second frame is output for resetting the criterion for determining the output level of the plurality of pixels. 
     Upon calculating the average luminance value of the first frame, the controller  170  may calculate an average luminance value of the second frame according to a predetermined cycle, and based on the average luminance value of the second frame, the controller  170  may reset the criterion for determining the output level of the plurality of pixels of the display  180  to output the second frame. 
     For example, the controller  170  may determine a gamma curve for the second frame based on the BSV of the second frame and may control the display  180  to output a second frame group, including the second frame, according to the gamma curve for the second frame. 
     For example, the controller  170  may control the display  180  to output the first frame group according to the gamma curve for the first frame, and then after the first frame group is output, the controller  170  may control the display  180  to output the second frame group including the second frame according to the gamma curve for the second frame. 
     Before the dynamic screen control function is terminated, the controller  170  may calculate the average luminance value of any one of the frames of an image according to a predetermined cycle, and may repeatedly reset the criterion for determining the output level of the plurality of pixels of the display  180 . 
     Meanwhile, the controller  170  may receive the RGB data and data regarding the criterion for determining the output level of the plurality of pixels of the display  180  from the image providing device  300  through the external device interface  130 . 
     If the dynamic screen control function is activated according to a user input signal, the controller  170  may transmit a signal indicative of the activated dynamic screen control function to the image providing device  300  through the external device interface  130  and may receive the RGB data and the data regarding the criterion for determining the output level of the plurality of pixels of the display  180  from the image providing device  300 . 
     For example, through the external device interface  130 , the controller  170  may transmit the signal indicative of the activated dynamic screen control function to the image providing device  300  and may receive the RGB data corresponding to the first frame group and the BSV data of the first frame from the image providing device  300 . 
     In this case, the controller  170  may determine the criterion for determining the output level of the plurality of pixels of the display  180  based on the BSV data of the first frame which are received from the image providing device  300 . 
     For example, based on the BSV data of the first frame which is received from the image providing device  300 , the controller  170  may determine the gamma curve for the first frame, and may control the display  180  to output the first frame group according to the gamma curve for the first frame. 
     The display  180  may convert an image signal, a data signal, an OSD signal, and a control signal processed by the controller  170  or an image signal, a data signal and a control signal received from the external device interface  130  to generate driving signals. 
     The display  180  may include a display panel (not shown) including a plurality of pixels. 
     The plurality of pixels included in the display panel may have RGB sub-pixels. Alternatively, the plurality of pixels included in the display panel may have RGBW sub-pixels. The display  180  may convert the video signal, data signal, OSD signal, and control signal processed by the controller  170  to generate signals for driving the plurality of pixels. 
     The display  180  may be a Plasma Display Panel (PDP), a Liquid Crystal Display (LCD), an Organic Light Emitting Diode (OLED), a flexible display, or the like, and may also be a three-dimensional (3D) display. The 3D display  180  may be divided into an autostereoscopic display and a glasses-type display. 
     Meanwhile, the display  180  may be configured as a touchscreen to be used as an input device in addition to an output device. 
     The audio output unit  185  receives an audio signal processed by the controller  170 , and outputs the audio signal as a sound. 
     The image signal, processed by the controller  170 , may be input to the display  180  to be displayed as an image corresponding thereto. Further, the image signal processed by the controller  170  may be input to an external output device through the external device interface  130 . 
     The audio signal processed by the controller  170  may be output as a sound to the audio output unit  185 . Further, the audio signal processed by the controller  170  may be input to an external output device through the external device interface  130 . 
     Although not illustrated in  FIG.  2   , the controller  170  may include a demultiplexer, a video processor, etc., which will be described below with reference to  FIG.  3   . 
     In addition, the controller  170  may control the overall operation of the image processing apparatus  100 . 
     For example, the controller  170  may control the tuner  110  to tune in to an RF broadcast channel selected by a user or a prestored channel. 
     In addition, the controller  170  may control the image processing apparatus  100  according to a user command input through the user input interface  150  or an internal program. 
     Meanwhile, the controller  170  may control the display  180  to display images. In this case, the images displayed on the display  180  may be still images or a video and may be 2D images or 3D images. 
     Meanwhile, the controller  170  may control a predetermined 2D object to be displayed in an image displayed on the display  180 . For example, the object may be at least one of an accessed web screen (newspaper, magazine, etc.), an electronic program guide (EPG), various menus, a widget, an icon, a still image, a video, and text. 
     Meanwhile, the image processing apparatus  100  may further include an image capturing unit (not shown). The image capturing unit may capture images of a user. The image capturing unit may be implemented with one camera, but is not limited thereto, and may be implemented with a plurality of cameras. Meanwhile, the image capturing unit may be embedded in the image processing apparatus  100  on the top of the display  180 , or may be provided separately. Image information captured by the image capturing unit may be input to the controller  170 . 
     The controller  170  may recognize a user&#39;s position based on the images captured by the image capturing unit. For example, the controller  170  may identify a distance (z-axis coordinates) between the user and the image processing apparatus  100 . In addition, the controller  170  may identify x-axis coordinates and y-axis coordinates corresponding to a user&#39;s position in the display  180 . 
     The controller  170  may sense a user&#39;s gesture based on the images captured by the image capturing unit or the respective signals sensed by the sensor unit, or a combination thereof. 
     The power supply unit  190  may supply power throughout the image processing apparatus  100 . Particularly, the power supply unit  190  may supply power to the controller  170  implemented in the form of a system on chip (SOC), the display  180  for image display, the audio output unit  185  for audio output, and the like. 
     Specifically, the power supply unit  190  may include a converter (not shown) for converting AC power into DC power and a DC/DC converter (not shown) for changing a DC power level. 
     The remote control device  200  may transmit a user input to the user input interface  150 . To this end, the remote control device  200  may use Bluetooth, Radio Frequency (RF) communication, Infrared Radiation communication, Ultra-Wideband (UWB), ZigBee and the like. Furthermore, the remote control device  200  may receive video, audio or data signals output from the user input interface  150 , and may display the received signals or may output the same as sound through the remote control device  200 . 
     Meanwhile, the aforementioned image processing apparatus  100  may be a fixed type or movable digital broadcast receiver capable of receiving digital broadcast. 
     Meanwhile, the block diagram of the image processing apparatus  100  illustrated in  FIG.  2    is merely a block diagram for an embodiment of the present disclosure. Components of the block diagram may be integrated, added or omitted according to specifications of the image display device  100   a  implemented in practice. 
     That is, two or more components may be combined or one component may be divided into two or more components as needed. Furthermore, a function executed in each block is for description of an embodiment of the present disclosure, and a specific operation or device of each block is not intended to limit the scope of the present disclosure. 
       FIG.  3    is an internal block diagram illustrating the controller of  FIG.  2   . 
     Referring to  FIG.  3   , the controller  170  according to an embodiment of the present disclosure may include a demultiplexer  310 , an image processing unit  320 , a processor  330 , an OSD generator  340 , a mixer  345 , a frame rate converter  350 , and/or a formatter  360 . In addition, an audio processing unit (not shown), and a data processing unit (not shown) may be further included. 
     The demultiplexer  310  demultiplexes the input stream. For example, when an MPEG-2 TS is input, it can be demultiplexed into image, audio, and data signal, respectively. Here, the stream signal input to the demultiplexer  310  may be a stream signal output from the tuner unit  110 , the demodulator  120 , or the external apparatus interface  130 . 
     The image processing unit  320  may perform image processing on the demultiplexed image signal. To this end, the image processing unit  320  may include an image decoder  325  and a scaler  335 . 
     The image decoder  325  decodes the demultiplexed image signal, and the scaler  335  performs scaling so that the resolution of the decoded image signal may be output to the display  180 . 
     The image decoder  325  may include a decoder of various standards. For example, a 3D image decoder for MPEG-2, H.264 decoder, a color image, and a depth image, and a decoder for a multiple view image may be provided. 
     The processor  330  may control the overall operation of the image processing apparatus  100  or the controller  170 . For example, the processor  330  may control the tuner  110  to tune in to an RF broadcast channel selected by a user or a prestored channel. 
     In addition, the processor  330  may control the image processing apparatus  100  by a user command input through the user input interface  150  or an internal program. 
     Further, the processor  330  may control data transmission with the network interface  135  or the external device interface  130 . 
     Moreover, the processor  330  may control operations of the demultiplexer  310 , the image processing unit  320 , the OSD generator  340 , and the like in the controller  170 . 
     The OSD generator  340  generates an OSD signal according to a user input or by itself. For example, based on a user input signal input through the input unit  160 , the OSD generator  340  may generate a signal for displaying a variety of information as a graphic or a text on the screen of the display  180 . 
     The generated OSD signal may include various data such as a user interface screen of the image processing apparatus  100 , various menu screens, a widget, and an icon. In addition, the generated OSD signal may include a 2D object or a 3D object. 
     In addition, the OSD generator  340  may generate a pointer that may be displayed on the display, based on a pointing signal input from the remote control device  200 . 
     The OSD generator  340  may include a pointing signal processing unit (not shown) for generating a pointer. The pointing signal processing unit (not shown) may be provided separately, rather than being provided in the OSD generator  240 . 
     The mixer  345  may mix an OSD signal generated by the OSD generator  340  with a decoded image signal image-processed by the image processing unit  320 . The mixed image signal may be supplied to the frame rate converter  350 . 
     The frame rate converter (FRC)  350  may convert the frame rate of an input image. Meanwhile, the frame rate converter  350  may also directly output the frame rate without any additional frame rate conversion. 
     The formatter  360  may arrange a left-eye video frame and a right-eye video frame of the 3D video signal subjected to frame rate conversion. Further, a synchronization signal Vsync may be output for opening the left-eye glass and the right-eye glass of the 3D viewing device (not shown). 
     Meanwhile, the formatter  360  may convert the format of an input image signal into an image signal to be displayed and output on the display  180 . 
     In addition, the formatter  360  may change the format of a 3D image signal. For example, the formatter  360  may change the format of the 3D image signal into any one of various 3D formats such as a side by side format, a top/down format, a frame sequential format, an interlaced format, a checker box format, and the like. 
     Meanwhile, the formatter  360  may convert a 2D image signal into a 3D image signal. For example, the formatter  360  may detect an edge or a selectable object in a 2D image signal according to a 3D image generation algorithm, and may separate and generate the object according to the detected edge or the selectable object as a 3D image signal. In this case, the generated 3D image signal may be divided into a left image signal L and a right image signal R and may be aligned, as described above. 
     Meanwhile, although not illustrated herein, a 3D processor (not shown) for 3-dimensional (3D) effect signal processing may be further disposed after the formatter  360 . The 3D processor may perform processing by adjusting brightness, tint, and color of an image signal to enhance the 3D effect. For example, signal processing may be performed to make a short distance in focus and to make a long distance out of focus, and the like. The function of the 3D processor may be integrated with the formatter  360  or the video processor  320 . 
     Meanwhile, the audio processor (not shown) in the controller  170  may voice-process the demultiplexed voice signal. To this end, the audio processor (not shown) may include various decoders. 
     In addition, the audio processor (not shown) in the controller  170  may adjust base, treble, volume, and the like. 
     The data processor (not shown) in the controller  170  may data-process the demultiplexed data signal. For example, when the demultiplexed data signal is an encoded data signal, the encoded data signal may be decoded. The encoded data signal may be electronic program guide (EPG) information including broadcast information such as start time and finish time of a broadcast program that is broadcast on each channel. 
     Meanwhile, the block diagram of the controller  170  illustrated in  FIG.  3    is merely a block diagram of an embodiment of the present disclosure, and components of the block diagram may be integrated, added, or omitted according to the specifications of the controller  170  implemented in practice. 
     Particularly, each of the frame rate converter  350  and the formatter  360  may be provided separately without being provided in the controller  170 , or may be provided separately as one module. 
       FIG.  4    is an internal block diagram illustrating an image processing apparatus according to another embodiment of the present disclosure. 
     The image processing apparatus of  FIG.  4    may be the image providing device  300  for providing images, such as a digital versatile disc (DVD) player, a Blu-ray player, a game console, a camera, a camcorder, a computer (laptop), a set-top box, and the like. 
     Referring to  FIG.  4   , the image providing device  300  may include an external device interface  430 , a network interface  435 , a storage  440 , a user input interface  450 , an input unit  460 , a controller  470 , and/or a power supply unit  490 . 
     The external device interface  430  may transmit or receive data to or from a connected external device (not shown), e.g., the image processing apparatus  100  illustrated in  FIG.  2   . To this end, the external device interface  130  may include an A/V input/output unit (not shown). 
     The external device interface  430  may be connected by wire/wirelessly to an image display apparatus, such as a TV, a monitor, etc., and may perform input/output operations for external devices. 
     In addition, the external device interface  430  may estimate a communication network with various remote control devices  200  as illustrated in  FIG.  1   , to receive a control signal related to the operation of the image providing device  300  from the remote control device  200  or to transmit data related to the operation of the image providing apparatus  300  to the remote control device  200 . In this case, the remote control device  200  may include various input devices, e.g., a mouse  200   a , a keyboard  200   b , and the like illustrated in  FIG.  1   . 
     The A/V input/output unit may transmit video and audio signals to an external device. 
     The external device interface  430  may include a wireless communication unit (not shown) for short-range wireless communication with other electronic devices. 
     Through the wireless communication unit (not shown), the external device interface  430  may exchange data with an adjacent mobile terminal. Particularly, the external device interface  430  may receive, from the mobile terminal, device information, running application information, application images, and the like in a mirroring mode. 
     The network interface  435  may provide an interface for connecting the image providing device  300  to a wired/wireless network including an Internet network. For example, the network interface  435  may receive content or data provided by the Internet, a content provider or a network operator through the network. 
     Meanwhile, the network interface  435  may include a communication module (not shown) for communication with a wired/wireless network. 
     The storage  440  may store programs for processing and controlling each signal within the controller  180 , and may store signal-processed video, audio or data signals. 
     For example, the storage  440  may store applications designed to perform various operations which may be processed by the controller  470 , and in response to a request from the controller  470 , the storage  440  may selectively provide some of the stored applications. 
     The programs and the like stored in the storage  440  are not particularly limited, as long as the programs may be executed by the controller  470 . 
     The user input interface  450  may transmit a signal, input by a user, to the controller  470  or may transmit a signal, input from the controller  470 , to the user. 
     For example, the user input interface  450  may transmit/receive a user input signal, and may transmit a user input signal input through a local key (not shown), such as a power key, to the controller  470 . 
     The input unit  460  may be provided on one side of a main body of the image providing device  300 . For example, the input unit  460  may include a touchpad, a physical button, and the like. 
     The input unit  460  may receive various user commands related to the operation of the image providing device  300 , and may transmit a control signal corresponding to the input command to the controller  470 . 
     The controller  470  may include at least one processor, and by using the included processor, the controller  470  may control the overall operation of the image providing device  300 . Here, the processor may be a general processor such as a central processing unit (CPU). Obviously, the processor is a dedicated device, such as an ASIC, or other hardware-based processor. 
     The controller  470  may transmit and receive a signal including data with an external device through the external device interface  430 . For example, the controller  470  may transmit RGB data, corresponding to an image, to the image processing apparatus  100  through the external device interface  430 . 
     The controller  470  may perform various functions related to the image processing apparatus  100 . 
     The controller  470  may activate a dynamic screen control function. For example, upon receiving a user command for activating the dynamic screen control function from the image display apparatus  100  through the external device interface  430 , or upon receiving the user command for activating the dynamic screen control function through the user input interface  450  or the input unit  460 , the controller  470  may activate the dynamic screen control function. 
     If the dynamic screen control function is activated, the controller  470  may calculate an average luminance value of any one of the plurality of frames of an image, and may determine a criterion for determining an output level of the plurality of pixels of the display  180  included in the image display apparatus  100 . 
     In this case, the controller  470  may repeatedly perform an operation of calculating the average luminance value of any one of the plurality of frames of an image according to a predetermined cycle, and may dynamically change the criteria for determining the output level of the plurality of pixels of the display  180  included in the image display apparatus  100 . 
     For example, the controller  470  may calculate an average luminance value of the first frame by extracting RGB data corresponding to the first frame from RGB data corresponding to images stored in the storage  440 . 
     In this case, the controller  470  may calculate the average luminance value of the first frame by extracting a portion of the RGB data corresponding to the first frame according to a predetermined criterion, thereby reducing the computation load of the controller  470 . 
     Here, the criterion for extracting a portion of the RGB data corresponding to the first frame may be determined based on a number of pixels on a screen of the display  180 , a screen ratio of the display  180 , and the like. 
     For example, if the display  180  included in the image display apparatus  100  has a screen ratio of 16:9, with the screen having 1920 pixels in width and 1080 pixels in height, the controller  470  may extract RGB data for 64 pixels in width and 36 pixels in height from the RGB data corresponding to the first frame. 
     In this case, a separation distance between the 64 pixels in width may be the same as a separation distance between the 36 pixels in height. 
     The controller  470  may convert the RGB data corresponding to the first frame into HSV data related to Hue, Saturation, and Value. 
     For example, the controller  170  may convert the RGB data corresponding to the first frame into hue data H, saturation data S, and value data V based on the above Equations 1, 2, and 3. 
     In this case, the controller  470  may calculate the average luminance value of the first frame based on the value data V, among the HSV data. For example, the controller  470  may calculate an average value Vavg of the value data V as the average luminance value of the first frame. 
     Based on the average luminance value of the first frame, the controller  470  may determine a criterion for determining an output level of the plurality of pixels of the display  180  included in the image display apparatus  100  for outputting the first frame. 
     In this case, considering that a user&#39;s eyes nonlinearly sense light, the controller  470  may determine the criterion for determining the output level of the plurality of pixels of the display  180  included in the image display apparatus  100  based on a logarithm value of the average luminance value of the first frame, as represented by the above Equation 4. 
     For example, the image providing device  300  may determine the BSV of the first frame as the criterion for determining the output level of the plurality of pixels of the display  180  included in the image display apparatus  100 , with the output level being associated with the output of the first frame group including the first frame. 
     Meanwhile, upon calculating the average luminance value of the first frame, the controller  470  may calculate an average luminance value of the second frame according to a predetermined cycle, and based on the average luminance value of the second frame, the controller  470  may redetermine the criteria for determining the output level of the plurality of pixels of the display  180  included in the image display apparatus  100  to output the second frame. 
     For example, upon calculating the BSV of the first frame, the controller  470  may calculate the BSV for the second frame according to a predetermined cycle. 
     The controller  470  may transmit data regarding the criteria for determining the output level of the plurality of pixels of the display  180 , included in the image display apparatus  100 , to the image display apparatus  100  through the external device interface  430 . 
     For example, for outputting the first frame group, the controller  470  may transmit BSV data on the first frame as the criteria for determining the output level of the plurality of pixels of the display  180  included in the image display apparatus  100 . 
       FIG.  5    is a flowchart illustrating a method of operating an image processing apparatus according to an embodiment of the present disclosure. 
     Referring to  FIG.  5   , the image processing apparatus  100  may check whether a dynamic screen control function is activated in operation S 510 . For example, upon receiving a user input for activating the dynamic screen control function through the input unit  160 , the image processing apparatus  100  may activate the dynamic screen control function. 
     If the dynamic screen control function is activated, the image processing apparatus  100  may calculate an average luminance value of any one of the plurality of frames of an image in operation S 520 . 
     For example, by extracting RGB data, corresponding to the first frame, from RGB data corresponding to the images stored in the image processing apparatus  100 , the image processing apparatus  100  may calculate an average luminance value of the first frame. 
     Based on the average luminance value of any one of the plurality of frames, the image processing apparatus  100  may set a criterion for determining an output level of the plurality of pixels of the display  180  in operation S 530 . 
     For example, the image processing apparatus  100  may determine a gamma curve, corresponding to a logarithm value of the average luminance value of the first frame, as a gamma curve for the first frame, and may determine the gamma curve for the first frame as a criterion for determining the output level of the plurality of pixels of the display  180 . 
     The image processing apparatus  100  may output an image according to the criterion for determining the output level of the plurality of pixels of the display  180  in operation S 540 . 
     For example, the image processing apparatus  100  may control the display  180  to output the first frame according to the gamma curve for the first frame. 
     In this case, the image processing apparatus  100  may control the display  180  to output the first frame group, including the first frame, according to the gamma curve for the first frame. 
     The image processing apparatus  100  may check whether a dynamic screen control function is terminated in operation S 550 . If the dynamic screen control function is not terminated, the procedure returns to operation S 520  in which the image processing apparatus  100  may calculate the average luminance value of the second frame among the plurality of frames according to a predetermined cycle, and may reset the criterion for determining the output level of the plurality of pixels of the display  180 . 
     In this case, the second frame may be a frame subsequent to a last output frame in the first frame group including the first frame. 
     That is, until the dynamic screen control function is terminated, the image processing apparatus  100  may calculate the average luminance value of any one of the plurality of frames of an image according to a predetermined cycle and may repeatedly reset the criterion for determining the output level of the plurality of pixels of the display  180 . 
       FIG.  6    is a flowchart illustrating a method of operating an image processing apparatus according to an embodiment of the present disclosure.  FIGS.  7  to  10 B  are diagrams referred to in the description of operation of an image processing apparatus according to various embodiments of the present disclosure. 
     Referring to  FIG.  6   , the image processing apparatus  100  may check whether a dynamic screen control function is activated in operation S 610 . For example, upon receiving a user input for activating the dynamic screen control function through the input unit  160 , the image processing apparatus  100  may activate the dynamic screen control function. 
     If the dynamic screen control function is activated, the image processing apparatus  100  may extract RGB data corresponding to any one of the plurality of frames of an image in operation S 620 . 
     In this case, the image processing apparatus  100  may extract a portion of the RGB data corresponding to the first frame according to a predetermined criterion. Here, the predetermined criterion for extracting a portion of the RGB data corresponding to the first frame may be determined based on a number of pixels on a screen of the display  180 , a screen ratio of the display  180 , and the like. 
     The image processing apparatus  100  may convert the RGB data corresponding to the first frame into HSV data in operation S 630 . 
     For example, the image processing apparatus  100  may convert the RGB data corresponding to the first frame into hue data H, saturation data S, and value data V, based on the above Equations 1 to 3. 
     The image processing apparatus  100  may calculate an average luminance value of the first frame based on the value data V, among the HSV data converted from the RGB data corresponding to the first frame, in operation S 640 . 
     For example, the image processing apparatus  100  may calculate an average value Vavg of the value data V as the average luminance value of the first frame. 
     The image processing apparatus  100  may calculate a logarithm value of the average luminance value of the first frame in operation S 650 . 
     For example, the image processing apparatus  100  may calculate the BSV of the first frame by calculating the logarithm value of the average luminance value of the first frame based on the above Equation 4. 
     In this case, as the average luminance value of the first frame decreases, the BSV of the first frame may increase. 
     Referring to  FIG.  7   , it can be seen that as the average value Vavg of the value data V, i.e., the average luminance value, decreases, the BSV increases. 
     In this case, it can be seen that as the BSV is calculated according to the logarithm value of the average luminance value, there is a nonlinear relationship between the average luminance value and the BSV. 
     Referring to  FIG.  8   , it can be seen that the average value Vavg of the value data V, i.e., the average luminance value, and the BSV change over time. 
     In this case, it can be seen that there is a correlation between a change in average luminance value and a change in BSV. For example, it can be seen that as shown at time points t 1  to t 3 , at the time when the average luminance value decreases, the BSV increases. 
     Referring back to  FIG.  6   , the image processing apparatus  100  may determine a gamma curve, corresponding to the logarithm value of the average luminance value of the first frame, as the criterion for determining the output level of the plurality of pixels of the display  180  in operation S 660 . 
       FIG.  9 A  illustrates the BSV of 0,  FIG.  9 B  illustrates the BSV of 40, and  FIG.  9 C  illustrates the BSV of 100 in a graph of a gamma curve for the first frame and a graph of a reference gamma curve, respectively. 
     Referring to  FIGS.  9 A to  9 C , it can be seen that as the average luminance value of the first frame decreases, i.e., the BSV increases, a difference between gamma curves  910 ,  920 , and  930  for the first frame and a reference gamma curve  900  increases in a low gray level area. Meanwhile, it can be seen that even when the average luminance value of the first frame increases or decreases, there is a constant difference between the gamma curves  910 ,  920 , and  930  for the first frame and the reference gamma curve  900  in a high gray level area. 
     Referring back to  FIG.  6   , the image processing apparatus  100  may output an image according to the criterion for determining the output level of the plurality of pixels of the display  180  in operation S 670 . 
     For example, the image processing apparatus  100  may control the display  180  to output the first frame based on the gamma curve for the first frame. 
     In this case, the image processing apparatus  100  may control the display  180  to output the first frame group, including the first frame, based on the gamma curve for the first frame. 
       FIG.  10 A  is a diagram illustrating an image output on a screen in the case where a dynamic screen control function is not activated, and  FIG.  10 B  is a diagram illustrating an image output on a screen in the case where a dynamic screen control function is activated. 
     Referring to  FIG.  10 A , it can be seen that when the dynamic screen control function is not activated, the image displayed on the screen is dark overall, and an average luminance value of the frames is low, such that a boundary between objects displayed on the screen or a boundary between a background and objects is not clear. 
     By contrast, referring to  FIG.  10 B , it can be seen that if the dynamic screen control function is activated, as the output level of the plurality of pixels of the display  180  increases in a low gray level area, such that a boundary between objects displayed on a screen or a boundary between a background and objects is clearly distinguished. 
     Referring back to  FIG.  6   , the image processing apparatus  100  may check whether the dynamic screen control function is terminated in operation S 680 . If the dynamic screen control function is not terminated, the procedure returns to operation S 620  in which the image processing apparatus  100  may calculate an average luminance value of the second frame, among the plurality of frames, according to a predetermined cycle, to reset the criterion for determining the output level of the plurality of pixels of the display  180 . 
     In this case, the second frame may be a frame subsequent to a last output frame in the first frame group including the first frame. 
       FIG.  11    is a flowchart illustrating a method of operating an image processing apparatus according to another embodiment of the present disclosure. 
     Referring to  FIG.  11   , the image providing device  300  as the image processing apparatus may transmit RGB data, corresponding to an image, to an external device (e.g., the image processing apparatus  100  of  FIG.  1   ) in operation S 1110 . For example, the image providing device  300  may transmit RGB data, corresponding to at least a portion of the plurality of frames of an image, to the image processing apparatus  100 . 
     The image providing device  300  may check whether a dynamic screen control function is activated in operation S 1120 . For example, upon receiving a user command for activating the dynamic screen control function from the image display apparatus  100  through the external device interface  430 , or upon receiving a user command for activating the dynamic screen control function through the user input interface  450  or the input unit  460 , the image processing apparatus  100  may activate the dynamic screen control function. 
     If the dynamic screen control function is activated, the image providing device  300  may calculate an average luminance value of any one of the plurality of frames of an image in operation S 1130 . 
     For example, the image providing device  300  may calculate an average luminance value of the first frame by extracting RGB data corresponding to the first frame from the RGB data corresponding to the image. 
     Based on the average luminance value of any one of the plurality of frames, the image providing device  300  may determine a criterion for determining the output level of the plurality of pixels of the display  180  included in the image display apparatus  100  in operation S 1140 . 
     For example, based on the average luminance value of the first frame, the image providing device  300  may determine the criterion for determining the output level of the plurality of pixels of the display  180  included in the image display apparatus  100 , with the output level being associated with the output of the first frame group including the first frame. 
     The image providing device  300  may transmit data regarding the criterion for determining the output level of the plurality of pixels of the display  180  included in the image display apparatus  100  to the image display apparatus  100  through the external device interface  430  in operation  51150 . 
     The image providing device  300  may check whether the dynamic screen control function is terminated in operation  51160 . If the dynamic screen control function is not terminated, the procedure returns to operation S 1130  in which the image providing device  300  may calculate an average luminance value of the second frame among the plurality of frames and may redetermine the criterion for determining the output level of the plurality of pixels of the display  180  included in the image display apparatus  100 . 
     The accompanying drawings are used to assist in easy understanding of various technical features and it should be understood that the embodiments presented herein are not limited by the accompanying drawings. As such, the present disclosure should be construed to extend to any alterations, equivalents and substitutes falling within the spirit and scope of the present disclosure. 
     Meanwhile, the method of operating the image processing apparatus of the present disclosure can be realized as a processor-readable code written on a processor-readable recording medium provided in the image processing apparatus. The processor-readable recording medium may be any type of recording device in which data is stored in a computer-readable manner. Examples of the processor-readable recording medium include a ROM, a RAM, a CD-ROM, a magnetic tape, a floppy disc, an optical data storage, and a carrier wave, e.g., data transmission through the Internet. The processor-readable recording medium can be distributed over a plurality of computer systems connected to a network so that a processor-readable code is written thereto and executed therefrom in a decentralized manner. 
     While the present disclosure has been shown and described with reference to the preferred embodiments thereof, it should be understood that the present disclosure is not limited to the aforementioned specific embodiments, and various modifications and variations may be made by those skilled in the art without departing from the scope and spirit of the invention as defined by the appended claims, and the modified implementations should not be construed independently of the technical idea or prospect of the present disclosure.