Abstract:
A display apparatus and a display method for displaying an image. The display method includes: receiving image frames; detecting motion values of front and back image ones of the received image frames; analyzing the detected motion values to determine whether a scene change occurs each preset time unit; and adjusting a brightness value of an image frame to be displayed according to whether the scene change occurs. Therefore, the display apparatus improves a loss of a contrast ratio occurring when varying a brightness of an image frame of each fraction in an occurrence of a scene change and improves a viewing visual brightness.

Description:
CROSS-REFERENCE TO RELATED APPLICATION 
       [0001]    This application claims priority under 35 U.S.C. §119 from Korean Patent Application No. 10-2015-0001079, filed on Jan. 6, 2015, in the Korean Intellectual Property Office, the disclosure of which is incorporated herein by reference in its entirety. 
       BACKGROUND 
       [0002]    1. Field 
         [0003]    A method and an apparatus consistent with exemplary embodiments broadly relate to providing a display apparatus and a display method for displaying an image, and more particularly to providing a display apparatus and a display method for displaying an image taking into consideration an occurrence of a scene change. 
         [0004]    2. Description of the Related Art 
         [0005]    In general, a scene change refers to a phenomenon in which after one of consecutive scenes of an image ends, another scene starts. Therefore, if a scene change rapidly occurs between front and back image frames, image quality setups, such as a color temperature, a color density, a color, a definition, a brightness, a contrast, etc., may be changed based on a corresponding environment. 
         [0006]    For this, if a plurality of image frames are input, an existing display apparatus adjusts a brightness of an image quality by using only brightness information of the input image frames. In detail, the existing display apparatus detects a motion value from a sum of brightness differences of pixels between image frames of respective fractions. The existing display apparatus compares the motion value detected from the image frames of the respective fractions with a preset reference value to vary brightness of the image frames of the respective fractions. 
         [0007]    However, the existing display apparatus varies the brightness of the image frames of the respective fractions based on the motion value detected from the image frames of the respective fractions and a fixed reference value. Therefore, a loss problem of a contrast ratio occurs. 
       SUMMARY 
       [0008]    Exemplary embodiments address at least the above problems and/or disadvantages and other disadvantages not described above. Also, the exemplary embodiments are not required to overcome the disadvantages described above, and an exemplary embodiment may not overcome any of the problems described above. 
         [0009]    Exemplary embodiments may provide an improvement of a contrast ratio loss that occurs when varying a brightness of an image frame of each fraction in an occurrence of a scene change and an improvement of a viewing visual brightness. 
         [0010]    According to an aspect of exemplary embodiments, there is provided a method of displaying an image including: receiving image frames; detecting motion values of front and back ones of the received image frames; determining whether a scene change occurs within a preset time based on the detected motion values; and adjusting a brightness value of an image frame, from among the plurality of image frames, to be displayed, based on the determining whether the scene change occurs. 
         [0011]    The motion values of the front and back image frames may be detected from a sum of brightness differences of pixels constituting the front and back image frames. 
         [0012]    In response to the detected motion values being higher than or equal to a reference value, the determining may yield that the scene change occurs between the front and back image frames. 
         [0013]    The method may further include: calculating a number of scene changes occurring within the preset time; and adjusting the reference value for determining whether the scene change occurs within the preset time, based on the calculated number of scene changes. 
         [0014]    In response to the calculated number of scene changes being higher than or equal to a threshold value, decreasing the reference value or maintaining the reference value unchanged. In response to the calculated number of scene changes being lower than the threshold value, increasing the reference value. 
         [0015]    The adjusting the brightness value may include: comparing a motion value, from the detected motion values, of the image frame with the adjusted reference value, in response to the compared motion value being higher than or equal to the adjusted reference value, decreasing the brightness value of the image frame, and in response to the compared motion value of the image frame being lower than the adjusted reference value, increasing the brightness value of the image frame. 
         [0016]    The method may further include: readjusting the adjusted reference value based on the brightness value of the image frame and an average brightness value of the image frame. The brightness value of the image frame may be readjusted based on the readjusted reference value and the motion value of the image frame. 
         [0017]    The readjusting of the adjusted reference value may include: in response to the brightness value of the image frame being higher than or equal to the adjusted reference value and the average brightness value of the image frame being higher than or equal to an average threshold value of the average brightness value, increasing the adjusted reference value; in response to the brightness value of the image frame being higher than or equal to the adjusted reference value and the average brightness value of the image frame being lower than the average threshold value of the average brightness value, lowering the adjusted reference value; and in response to the brightness value of the image frame being lower than the adjusted reference value, increasing the reference value. 
         [0018]    According to another aspect of exemplary embodiments, there is provided a display apparatus including: an image input interface configured to receive a number of image frames; a motion detector configured to detect motion values of front and back ones of the received image frames; and a controller configured to determine whether a scene change occurs within a preset time based on the detected motion values and adjust a brightness value of an image frame, from among the number of image frames, to be displayed, based on the determining whether the scene change occurs. 
         [0019]    The motion detector may detect the motion values of the front and back image frames from a sum of brightness differences of pixels constituting the front and back image frames. 
         [0020]    In response to the motion detector detecting that the motion values are higher than or equal to a reference value, the controller may determine that the scene change occurs between the front and back image frames. 
         [0021]    The controller may calculate a number of scene changes occurring within the preset time and adjust the reference value for determining whether the scene change occurs within the preset time, based on the calculated number of scene changes. 
         [0022]    In response to the controller determining that the number of scene changes is higher than or equal to a threshold value, the controller may decrease the reference value or maintain the reference value unchanged, and in response to the controller determining that the number of scene changes is lower than the threshold value, the controller may increase the reference value. 
         [0023]    The controller may compare a motion value, from among the motion values detected by the motion detector, of the image frame with the adjusted reference value, in response to the motion value of the image frame being higher than or equal to the adjusted reference value as compared by the controller, the controller may decrease the brightness value of the image frame, and in response to the motion value of the image frame being lower than the adjusted reference value as compared by the controller, the controller may increase the brightness value of the image frame. 
         [0024]    The controller may readjust the adjusted reference value based on the brightness value and an average brightness value of the image frame and may readjust the brightness value of the image frame based on the readjusted reference value and the motion value of the image frame detected by the motion detector. 
         [0025]    In response to the brightness value of the image frame being higher than or equal to the readjusted reference value and the average brightness value of the image frame being higher than or equal to an average threshold value of the average brightness value, the controller may decrease the readjusted reference value. In response to the brightness value of the image frame being higher than or equal to the readjusted reference value and the average brightness value of the image frame being lower than the average threshold value of the average brightness value, the controller may increase the readjusted reference value. In response to the brightness value of the image frame being lower than the readjusted reference value, the controller may increase the readjusted reference value. 
     
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         [0026]    The above and/or other aspects will be more apparent by describing exemplary embodiments with reference to the accompanying drawings, in which: 
           [0027]      FIG. 1  is a block diagram illustrating a configuration of a display apparatus according to an exemplary embodiment; 
           [0028]      FIG. 2  is a block diagram illustrating a configuration of a display apparatus according to an exemplary embodiment; 
           [0029]      FIG. 3  is a block diagram illustrating a controller according to an exemplary embodiment; 
           [0030]      FIG. 4  is a graph illustrating a distribution of input image frames in a display apparatus according to an exemplary embodiment; 
           [0031]      FIG. 5  is a flowchart illustrating a method of displaying an image using a display apparatus according to an exemplary embodiment; 
           [0032]      FIG. 6  is a flowchart illustrating a method of adjusting a reference value for adjusting a brightness value of an image frame according to an exemplary embodiment; and 
           [0033]      FIG. 7  is a flowchart illustrating a method of readjusting a reference value to readjust a brightness value of an image frame according to an exemplary embodiment. 
       
    
    
     DETAILED DESCRIPTION OF EXEMPLARY EMBODIMENTS 
       [0034]    Exemplary embodiments are described in greater detail with reference to the accompanying drawings. 
         [0035]    In the following description of exemplary embodiments, the same drawing reference numerals are used to denote analogous elements even in different drawings. The matters defined in exemplary embodiments, such as detailed construction and elements, are provided to assist in a comprehensive understanding of exemplary embodiments. Thus, it is apparent that exemplary embodiments can be carried out without those specifically defined matters. Also, well-known functions or constructions are not described in detail since they would obscure exemplary embodiments with unnecessary detail. 
         [0036]      FIG. 1  is a block diagram illustrating a display apparatus  100  according to an exemplary embodiment. 
         [0037]    As shown in  FIG. 1 , the display apparatus  100  may be an apparatus that may display an image received from an external device or a pre-stored image, like a smartphone, a tablet PC, or a smart TV. The display apparatus  100  includes an image input interface  110 , a motion detector  120 , and a controller  130 . 
         [0038]    The image input interface  110  receives a plurality of image frames of an image to be displayed. The motion detector  120  detects motion values from front and back image frames input through the image input interface  110 . The controller  130  controls overall operations of the elements of the display apparatus  100 . In particular, in an exemplary embodiment, the controller  130  analyzes the motion values detected by the motion detector  120  to determine whether a scene change occurs in each preset time unit or period of time and adjusts a brightness value of an image frame to be displayed, according to the determination result. 
         [0039]    In detail, according to an exemplary embodiment, if front and back image frames are input through the image input interface  110 , the motion detector  120  detects motion values of the front and back image frames from a sum of brightness differences of pixels constituting the input front and back image frames. 
         [0040]    According to exemplary embodiments, a first image frame may be input, and then a second image frame may be input through the image input interface  110 . If consecutive first and second image frames are input, as described above, the motion detector  120  acquires a difference between brightness of pixels of the first image frame and brightness of pixels of the second image frame. The motion detector  120  may sum values of the differences of the pixels of the first and second image frames to detect the summed result value as a motion value of the first and second image frames. 
         [0041]    According to an exemplary embodiment, if the motion values of the front and back image frames are detected, the controller  130  may determine whether the motion values detected from the front and back image frames are higher than or equal to a preset reference value and adjust a brightness value of an image frame to be displayed, based on the determination result. 
         [0042]    In detail, if the motion values detected from the front and back image frames are higher than or equal to the preset reference value, the controller  130  determines that a scene change occurred between the front and back image frames. The controller  130  repeatedly performs a series of operations, as described above, to calculate the number of scene changes occurring within a preset unit or period of time. The controller  130  adjusts a reference value for determining whether a scene change occurs within a preset unit or period of time, based on the number of scene changes calculated within the preset unit or period of time. In other words, according to an exemplary embodiment, the controller  130  may adjust a reference value that is set to determine whether an input image frame is a motion image or a still image, based on the number of scene changes calculated within the preset unit or period of time. 
         [0043]    According to exemplary embodiments, if the number of scene changes calculated within the preset unit or period of time is higher than or equal to a preset threshold value, the controller  130  may lower a reference value for determining whether a scene change occurs, by a value of a preset level or may keep the reference value. If the number of scene changes calculated within the preset unit time is lower than the preset threshold value, the controller  130  increases the reference value for determining whether the scene change occurs, by a value of a preset level. 
         [0044]    If the reference value for determining whether the scene change occurs is adjusted based on the above-described conditions, the controller  130  adjusts a brightness value of a corresponding image frame base on the adjusted reference value and a motion value of an input image frame. 
         [0045]    According to one or more exemplary embodiments, the controller  130  compares the adjusted reference value with a motion value of a first image frame to be displayed and, if the motion value of the first image frame is higher than or equal to the adjusted reference value, decreases a brightness value of the first image frame. Here, if the motion value of the first image frame is higher than or equal to the adjusted reference value, the controller  130  may decrease the brightness value of the first image frame within a preset minimum brightness value. 
         [0046]    If the motion value of the first image frame is lower than the adjusted reference value, the controller  130  increases the brightness value of the first image frame to be displayed. Here, if the motion value of the first image frame is lower than the adjusted reference value, the controller  130  may increase the brightness value of the first image frame within a preset maximum brightness value. 
         [0047]    As described above, according to an exemplary embodiment, the display apparatus  100  may adjust a reference value for determining whether an input image frame is a motion image or a still image based on the number of scene changes occurring within a preset unit or period of time. Also, the display apparatus  100  adjust a brightness value of the input image frame based on the adjusted reference value to minimize a loss of a contrast ratio and provide a high visual brightness. 
         [0048]    According to yet another exemplary embodiment, the controller  130  may adjust a reference value for determining whether an input image frame is a motion image or a still image. 
         [0049]    In detail, the controller  130  may readjust an adjusted reference value based on a brightness value of an image frame increasing or decreasing based on the adjusted reference value and an average brightness value of the corresponding image frame. As described above, according to an exemplary embodiment, the controller  130  compares a motion value of a first image frame to be displayed with the adjusted reference value, if the motion value of the first image frame is higher than or equal to the adjusted reference value, decreases a brightness value of the first image frame, and if the motion value of the first image frame is lower than the adjusted reference value, increases the brightness value of the first image frame. 
         [0050]    If the brightness value of the first image frame is adjusted based on the motion value of the first image frame and the adjusted reference value, as described above, the controller  130  readjusts the adjusted reference value based on the adjusted brightness value of the first image frame and an average brightness value of the first image frame. 
         [0051]    In detail, according to an exemplary embodiment, if the brightness value of the first image frame is higher than or equal to the adjusted reference value, and the average brightness value of the first image frame is higher than or equal to an average threshold value of the corresponding average brightness value, the controller  130  increases the adjusted reference value by a value of a preset level. If the brightness value of the first image frame is higher than or equal to the adjusted reference value, and the average brightness value of the first image frame is lower than the average threshold value of the corresponding average brightness value, the controller  130  lowers the adjusted reference value by a value of a preset level. If the brightness value of the first image frame is lower than the adjusted reference value, the controller  130  lowers the adjusted reference value by the value of the preset level. 
         [0052]    The controller  130  may compare the motion value of the first image frame with the readjusted reference value, if the motion value of the first image frame is higher than or equal to the readjusted reference value, decrease the brightness value of the first image frame, and if the motion value of the first image frame is lower than the readjusted reference value, increase the brightness value of the first image frame. 
         [0053]    As described above, according to an exemplary embodiment, the display apparatus  100  may adjust a reference value for determining whether an input image frame is a motion image or a still image according to the number of scene changes occurring within a unit or a period of time. Also, the display apparatus  100  may increase or decrease a brightness value of an image to be displayed based on the adjusted reference value so as to improve an average brightness of the input image frame. 
         [0054]    The display apparatus  100 , which displays an image frame by using a brightness value adjusted based on a motion value of an input image frame and a preset reference value, may further include additional elements that will be described below, according to an exemplary embodiment. 
         [0055]      FIG. 2  is a block diagram illustrating a display apparatus according to an exemplary embodiment. 
         [0056]    As shown in  FIG. 2 , the display apparatus  100  may include a communicator  140 , an image processor  150 , a display  160 , and a storage  170  and also include an image input interface  110 , a motion detector  120 , and a controller  130  such as the ones described above with reference to  FIG. 1 . 
         [0057]    The communicator  140  may perform a data communication with an external device (not shown) to receive a plurality of image frames of an image from the external device. The communicator  140  may include a wireless communication module and a wire communication module. Here, the wire communication module may be a universal serial bus (USB) communication module that provides an interface with the external device, and the wireless communication module may include at least one selected from a short range communication module and a long range communication module. The short range communication module may include at least one selected from a WIFI direct communication module, a Bluetooth module, an infrared data association (IrDA) module, a near field communication (NFC) module, and a Zigbee module. The long range communication module may include at least one selected from a cellular communication module, a 3rd generation (3G) mobile communication module, a 4th generation (4G) mobile communication module, and a 4G long term evolution (LTE) communication module. 
         [0058]    The image processor  150  converts an image frame input via the image input interface  110  into YCbCr data, determines an image black level, and adjust a sensitivity ratio of each color. The image processor  150  may also perform a white balance, a gamma correction, a color interpolation, a color correction, a resolution conversion, etc. on the input image frame, according to an exemplary embodiment. Therefore, the motion detector  120  may acquire brightness differences of pixels of front and back image frames, which are image-processed through the image processor  150 , and detect motion values of the front and back image frames from a sum of the brightness differences. 
         [0059]    The display  160  displays an image, in particular, may display an image frame, a brightness value of which is adjusted by the controller  130 , according to an exemplary embodiment. In addition, the display  160  may upscale or downscale an image frame to be displayed based on a screen size of the display apparatus  100 , convert frame rates of scaled image frames with reference to a display rate, and display an image. The display  160  may be realized as a liquid crystal display (LCD), an organic light-emitting display, a plasma display panel (PDP), or the like. 
         [0060]    The storage  170  may be a storage medium (e.g., a memory) that stores various types of programs, etc. necessary for operating the display apparatus  100 . In particular, in an exemplary embodiment, the storage  170  may store a reference value that is set to determine whether a scene change occurs within each preset time unit or period of time. The storage  170  may include a read only memory (ROM) for storing a program for performing an operation of the controller  130 , a random access memory (RAM) for temporarily storing data generated by a performance of the operation of the controller  130 , etc. The storage  170  may further include an electrically erasable and programmable ROM (EEROM) for storing various types of reference data. 
         [0061]    Elements of the controller such as the controller  130 , described above, will now be described in detail, according to an exemplary embodiment. 
         [0062]      FIG. 3  is a block diagram illustrating a controller according to an exemplary embodiment. 
         [0063]    Referring to  FIG. 3 , the controller  130  may include a scene change detector  131 , a brightness controller  132 , and an average brightness detector  133 . 
         [0064]    If motion values of front and back image frames detected through the motion detector  120  are higher than or equal to a preset reference value, for example as described above, the scene change detector  131  determines that a scene change occurs between the front and back image frames. The scene change detector  131  determines whether scene changes of a plurality of image frames included within a preset time unit or a predetermined period of time occur. 
         [0065]    If the scene change detector  131  determines whether the scene changes of the plurality of image frames within the preset time unit occur, the brightness controller  132  adjusts a reference value for determining whether a scene change occurs within a preset unit time or a predetermined period of time, based on the number of scene changes occurring within the preset time unit or a predetermined period of time. 
         [0066]    In detail, if the number of scene changes occurring within the preset time unit or a predetermined period of time is higher than or equal to a preset threshold value, the brightness controller  132  lowers a preset reference value by a preset size or a preset amount, or keeps the preset reference value. If the number of scene changes occurring within the preset unit time or a predetermined period of time is lower than the preset threshold value, the brightness controller  132  increases the reference value for determining whether the scene change occurs, by a preset size or amount. The brightness controller  132  compares a motion value of an image frame to be displayed with the adjusted reference value and, if the motion value of the image frame is higher than or equal to the adjusted reference value, decreases a brightness value of the image frame by a preset size. If the motion value of the image frame to be displayed is lower than the adjusted reference value, the brightness controller  132  increases the brightness value of the image frame by a preset size. 
         [0067]    If an average brightness value of the image frame to be displayed is input through the average brightness detector  133 , the brightness controller  132  readjusts the adjusted reference value based on the brightness value that decreases or increases based on the input average brightness value and the adjusted reference value. 
         [0068]    In detail, according to an exemplary embodiment, if the brightness value of the image frame to be displayed is higher than or equal to the adjusted reference value, and the average brightness value of the image frame is higher than or equal to an average threshold value of the average brightness value, the brightness controller  132  increases the adjusted reference value by a preset size or amount. If the brightness value of the image frame to be displayed is higher than or equal to the adjusted reference value, and the average brightness value of the image frame is lower than the average threshold value, the brightness controller  132  decreases the adjusted reference value by a preset size or amount. If the brightness value of the image frame to be displayed is lower than the adjusted reference value, the brightness controller  132  increases the adjusted reference value by a preset size or amount. 
         [0069]    If the adjusted reference value is readjusted, for example, as described above, the brightness controller  132  may compare a motion value of the image frame to be displayed with the readjusted reference value. Also, the brightness controller  132  may decreases the brightness value of the image frame by a preset size if the motion value of the image frame is higher than or equal to the readjusted reference value and increase the brightness value of the image frame by a preset size or amount if the motion value of the image frame is lower than the readjusted reference value. 
         [0070]      FIG. 4  is a graph illustrating a distribution of input image frames in a display apparatus, according to an exemplary embodiment. 
         [0071]    As shown in  FIG. 4 , the display apparatus  100  may receive a plurality of image frames through the image input interface  110 . For example, if  600  image frames are input at 10-second intervals, image frames having motion values lower than a reference value may be input in fractions a and b based on a preset reference value (motion th)  410 , and ones of a plurality of image frames having motion values higher than or equal to the reference value may be input in fractions c through e. In this case, the brightness controller  132  calculates the number of scene changes occurring in each fraction and lowers or increases the reference value by a preset size or amount based on the number of scene changes calculated in each fraction. 
         [0072]    As shown in  FIG. 4 , if the number of scene changes occurring in the fractions c through e is higher than or equal to a preset threshold value, the brightness controller  132  lowers the reference value of the fractions c through e by a preset size or amount or keeps the reference value. If the number of scene changes is lower than the preset threshold value, the brightness controller  132  may increase a reference value of the fractions a and b by a preset size or amount. 
         [0073]    If a reference value of each fraction is adjusted according to the number of scene changes calculated in each fraction, the brightness controller  132  may compare a motion value of an image frame of each fraction with the adjusted reference value of each fraction, decrease a brightness value of an image frame having a motion value higher than or equal to the adjusted reference value, and increase a brightness value of an image frame having a motion value lower than the adjusted reference value. 
         [0074]    The elements of the display apparatus  100  according to an exemplary embodiment have been described in detail. A method of displaying an image through the display apparatus  100  according to an exemplary embodiment will now be described in detail. 
         [0075]      FIG. 5  is a flowchart illustrating a method of displaying an image according to an exemplary embodiment. 
         [0076]    Referring to  FIG. 5 , in operation S 510 , a plurality of image frames of an image to be displayed are input. In operation S 520 , the display apparatus  100  detects motion values of the plurality of image frames. In detail, if a plurality of image frames of an image to be displayed are input, the display apparatus  100  detects motion values from the input front and back image frames. According to exemplary embodiments, the display apparatus  100  may detect motion values of front and back image frames from a sum of brightness differences of pixels constituting the front and back image frames. 
         [0077]    If the motion values of the front and back image frames are detected, the display apparatus  100  analyzes the detected motion values to determine whether a scene change occurs within each preset unit time or amount of time and adjusts a reference value for determining whether the scene change occurs within a preset unit time or amount of time, based on the determination result in operation S 530 . In detail, if the motion values detected from the input front and back image frames are higher than or equal to a preset reference value, the display apparatus  100  determines that a scene change occurs between the front and back image frames. The display apparatus  100  repeatedly performs a series of operations, such as the one described above, to calculate the number of scene changes occurring within a preset unit time or period of time and adjusts the reference value for determining whether the scene change occurs within the preset unit time or period of time, based on the number of scene changes. In operation S 540 , the display apparatus  100  adjusts the adjusted reference value and a brightness value of an image frame to be displayed. Therefore, the display apparatus  100  may display an image frame based on the adjusted brightness value, according to an exemplary embodiment. 
         [0078]    A method of adjusting a reference value for determining whether a scene change occurs within a preset unit or period of time using the display apparatus  100  according to an exemplary embodiment will now be described in detail. 
         [0079]      FIG. 6  is a flowchart illustrating a method of adjusting a reference value for adjusting a brightness value of an image frame, according to an exemplary embodiment. 
         [0080]    Referring to  FIG. 6 , in operation S 610 , the display apparatus  100  calculates the number of scene changes occurring within a preset unit or period of time. If motion values detected from input front and back image frames are higher than or equal to a preset reference value, such as the ones described above, the display apparatus  100  determines that a scene change occurs between the input front and back image frames. The display apparatus  100  may repeatedly perform a series of operations, such as the ones described above, to calculate the number of scene changes occurring within the preset unit or period of time. 
         [0081]    If the number of scene changes occurring within the preset unit or period of time is calculated, the display apparatus  100  adjusts a reference value for determining whether the scene change occurs within the preset unit or period of time, based on the number of scene changes. In detail, according to an exemplary embodiment, if the number of scene changes occurring within the preset unit or period of time is calculated, the display apparatus  100  determines whether the number of scene changes is lower than a preset threshold value in operation S 620 . 
         [0082]    If it is determined that the number of scene changes is lower than the preset threshold value, the display apparatus  100  increases the reference value for determining whether the scene change occurs, by a value of a preset level or amount, in operation S 630 . If the number of scene changes is higher than or equal to the preset threshold value, the display apparatus  100  lowers the reference value for determining whether the scene change occurs, by a value of a preset level or amount or keeps the reference value as is, in operation S 640 . 
         [0083]    If the reference value for determining whether the scene change occurs is adjusted based on the above-described exemplary condition, the display apparatus  100  adjusts a brightness value of a corresponding image frame based on the adjusted reference value and a motion value of an input image frame, such as the one described above with reference to operation S 540 . 
         [0084]    According to exemplary embodiments, the display  100  may compare a motion value of a first image frame to be displayed with an adjusted reference value. If the motion value of the first image frame is higher than or equal to the adjusted reference value, the display apparatus  100  may decrease a brightness value of the first image frame. Here, according to an exemplary embodiment, the display apparatus  100  may decrease the brightness value of the first image frame within a preset minimum brightness value. If the motion value of the first image frame to be displayed is lower than the adjusted reference value, the display apparatus  100  increases the brightness value of the first image frame. Here, according to an exemplary embodiment, the display apparatus  100  may increase the brightness value of the first image frame within a preset maximum brightness value. 
         [0085]    As described above, according to an exemplary embodiment, the display apparatus  100  may adjust a reference value for determining whether an input image frame is a motion image or a still image, based on the number of scene changes occurring within a preset unit or period of time. The display apparatus  100  may also adjust a brightness value of the input image frame based on the adjusted reference value so as to minimize a loss of a contrast ratio and provide a high visual brightness. 
         [0086]    The display apparatus  100  may readjust the adjusted reference value based on a brightness value of an image frame (hereinafter referred to as a first image frame) that decreases or increases based on the adjusted reference value and an average brightness value of the first image frame. 
         [0087]      FIG. 7  is a flowchart illustrating a method of readjusting a reference value that is adjusted to adjust a brightness value of an image frame, according to an exemplary embodiment. 
         [0088]    Referring to  FIG. 7 , in operation S 710 , the display apparatus  100  acquires a motion value of a first image frame to be displayed. In operation S 720 , the display apparatus  100  compares the motion value of the first image frame with an adjusted reference value. If the motion value of the first image frame is lower than the adjusted reference value according to the comparison result, the display apparatus  100  increases a brightness value of the first image frame in operation S 730 . If the motion value of the first image frame is higher than or equal to the adjusted reference value, the display apparatus  100  decreases the brightness value of the first image frame in operation S 740 . 
         [0089]    If the brightness value of the first image frame is adjusted based on the motion value of the first image frame and the adjusted reference value, the display apparatus  100  readjusts the adjusted reference value based on the adjusted brightness value of the first image frame and an average brightness value of the first image frame in operation S 750 . In detail, according to an exemplary embodiment, if the brightness value of the first image frame is higher than or equal to the adjusted reference value, and the average brightness value of the first image frame is higher than or equal to an average threshold value of the average brightness value, the display apparatus  100  increases the adjusted reference value by a value of a preset level or size. If the brightness value of the first image frame is higher than or equal to the adjusted reference value, and the average brightness value of the first image frame is lower than the average threshold value of the average brightness value, the display apparatus  100  lowers the adjusted reference value by a value of a preset level or size. If the brightness value of the first image frame is lower than the adjusted reference value, the display apparatus  100  lowers the adjusted reference value by a value of a preset level or size. 
         [0090]    The display apparatus  100  may compare the motion value of the first image frame with the readjusted reference value, if the motion value of the first image frame is higher than or equal to the readjusted reference value, decrease the brightness value of the first image frame, and if the motion value of the first image frame is lower than the readjusted reference value, increase the brightness value of the first image frame. 
         [0091]    As described above, according to an exemplary embodiment, the display apparatus  100  may adjust a reference value for determining whether an input image frame is a motion image or a still image, according to the number of scene changes occurring each unit or period of time. The display apparatus  100  may also increase or decrease a brightness value of an image frame to be displayed, based on the adjusted reference value so as to improve an average brightness of an input image frame. 
         [0092]    According to various exemplary embodiments, described above, a display apparatus may adjust a reference value for determining whether an input image frame is a motion image or a still image based on the number of scene changes. The display apparatus may also adjust a brightness value of the input image frame based on the adjusted reference value so as to minimize a loss of a contrast ratio and provide a high visual brightness. 
         [0093]    The foregoing exemplary embodiments are merely exemplary and are not to be construed as limiting. Exemplary embodiments can be readily applied to other types of apparatuses. Also, the description of exemplary embodiments is intended to be illustrative, and not to limit the scope of the claims, and many alternatives, modifications, and variations will be apparent to those skilled in the art. One of ordinary skill in the art would readily appreciate that exemplary embodiments and modifications conceived from the meaning and scope of the claims and their equivalents are included in the scope of the present disclosure.