Abstract:
In an apparatus and method for controlling an interface, a user interface (UI) may be controlled using information on a hand motion and a gaze of a user without separate tools such as a mouse and a keyboard. That is, the UI control method provides more intuitive, immersive, and united control of the UI. Since a region of interest (ROI) sensing the hand motion of the user is calculated using a UI object that is controlled based on the hand motion within the ROI, the user may control the UI object in the same method and feel regardless of a distance from the user to a sensor. In addition, since positions and directions of view points are adjusted based on a position and direction of the gaze, a binocular 2D/3D image based on motion parallax may be provided.

Description:
CROSS-REFERENCE TO RELATED APPLICATIONS 
     This application claims the benefit of Korean Patent Application Nos. 10-2010-0082848, filed on Aug. 26, 2010, and 10-2011-0046174 filed on May 17, 2011, in the Korean Intellectual Property Office, the disclosure of which is incorporated herein by reference. 
     BACKGROUND 
     1. Field 
     Example embodiments relate to an apparatus and method for controlling an interface, and more particularly, to an apparatus and method for controlling a 2-dimensional or 3-dimensional graphic user interface (2D/3D GUI). 
     2. Description of the Related Art 
     Recently, a natural interface technology has been on the rise. A natural interface enables more natural and intuitive communication between a person and a computer. Active research is underway to recognize a user&#39;s intention and motion and therefore achieve interactive communication between the person and the computer. In particular, an interactive display is being rapidly developed to provide a more natural computing environment than a keyboard and a mouse which are typical user interfaces (UI). 
     According to conventional interactive displays, a UI may be operated by multi-touch and hover performed on a surface of the display. Whereas the mouse and the keyboard provide an indirect interaction where a gaze and an operation space of the user do not correspond to each other, the multi-touch and hover enables a direct interaction where the gaze and the operation space correspond to each other, thereby achieving a more natural operation. However, the multi-touch method provides only a 2-dimensional (2D) interaction applicable only on a displaying surface. That is, when an operation object of the UI is 3D, the object may not be intuitively operated as though the user were manipulating an actual object. In case of the hover method, the object may not be operated immersively and unitedly only by information regarding the hand of the user. 
     Currently, a display apparatus providing 3D images is widely used. A person may perceive a 3D image by a stereoscopic method that inputs images to both left and right eyes and a motion parallax method that varies a distance of an object and a horizontal movement of left and right images according to a person&#39;s point of view. Demand for the 3D image are steadily increasing. 
     Accordingly, a 3D user interface (3D UI) providing a more immersive feel and sense of unity, and an improved apparatus and method for controlling the 3D UI is desired. 
     SUMMARY 
     Additional aspects and/or advantages will be set forth in part in the description which follows and, in part, will be apparent from the description, or may be learned by practice of the invention. 
     The foregoing and/or other aspects are achieved by providing an interface control apparatus comprising a receiver to receive image information including a depth image related to a user from a sensor; a processor to generate, based on the image information, at least one of motion information regarding a hand motion of the user and gaze information regarding a gaze of the user; and a controller to control a 2-dimensional or 3-dimensional graphical user interface (2D/3D GUI) based on at least one of the motion information and the gaze information. 
     The foregoing and/or other aspects are achieved by providing an interface control method comprising receiving image information including a depth image related to a user from a sensor, generating, based on the image information, at least one of motion information regarding a hand motion of the user and gaze information regarding a gaze of the user; and controlling a 2D/3D GUI based on at least one of the motion information and the gaze information. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
       These and/or other aspects and advantages will become apparent and more readily appreciated from the following description of the example embodiments, taken in conjunction with the accompanying drawings of which: 
         FIG. 1  illustrates an interface control system according to example embodiments; 
         FIG. 2  illustrates a structure of an interface control apparatus according to example embodiments; 
         FIG. 3  illustrates a region of interest (ROI) according to example embodiments; 
         FIG. 4  illustrates a depth image according to example embodiments; 
         FIG. 5  illustrates a control start interaction and a control end interaction according to example embodiments; 
         FIG. 6  illustrates various interactions according to example embodiments; 
         FIG. 7  illustrates a fixed interaction according to example embodiments; 
         FIG. 8  illustrates an interaction using a gaze of a user according to example embodiments; 
         FIG. 9  illustrates a fixed interaction using a gaze of a user according to example embodiments; 
         FIG. 10  illustrates an operation region according to example embodiments; 
         FIG. 11  illustrates a structure of a generator of an interface control apparatus according to example embodiments; 
         FIG. 12  illustrates a 2-dimensional or 3-dimensional graphical user interface (2D/3D GUI) according to example embodiments; 
         FIG. 13  illustrates an operation of an interface control apparatus controlling a 2D/3D GUI in accordance with a position of a user, according to example embodiments; and 
         FIG. 14  illustrates a flowchart explaining an interface control method according to example embodiments. 
     
    
    
     DETAILED DESCRIPTION 
     Reference will now be made in detail to example embodiments, examples of which are illustrated in the accompanying drawings, wherein like reference numerals refer to the like elements throughout. Example embodiments are described below to explain the present disclosure by referring to the figures. 
       FIG. 1  illustrates an interface control system according to example embodiments. 
     Referring to  FIG. 1 , the interface control system includes an interface control apparatus  100 , a sensor  110 , and a display apparatus  140 . 
     The sensor  110  senses an image related to a user  120 . The sensor according to an embodiment may be a camera, for example. The sensor  110  may take a depth image regarding a distance from the sensor  110  to the user  120  and transmit image information including the depth image to the interface control apparatus  100 . 
     Depending on embodiments, the sensor  110  may further take a color image, or an IR image, or both, related to a user and transmit image information further including the color image and the IR image to the interface control apparatus  100 . 
     The interface control apparatus  100  receives the image information related to the user  120  from the sensor  110 . Based on the received image information, the interface control apparatus  100  may generate motion information regarding a motion of the hand  122  of the user  120 . 
     According to an embodiment, the motion information may include information including one or more of, or any combination thereof, of a motion path of the hand  122  of the user  120 , for example regarding whether the hand  122  is moving upward or downward, a posture of the hand  122 , for example regarding whether the hand  122  is in an opened state and a closed state, and the number of the hand  122 , for example regarding whether one hand  122  or both hands  122  are used. 
     The interface control apparatus  100  may generate gaze information regarding a gaze  121  of the user  120 , based on the received image information. 
     The gaze information according to an embodiment may include one or more of, or any combination thereof, of a direction of the gaze  121 , a position reached by the gaze  121 , and a position of a head of the user. 
     The interface control apparatus  100  controls a 2-dimensional or 3-dimensional graphical user interface (2D/3D GUI)  130  based on the motion information. The 2D/3D GUI  130  may display at least one UI object, for example, UI objects  131 ,  132 , and  133 . 
     Depending on embodiments, when a position of the hand  122  may correspond to a position of a web browser UI object  131  of the 2D/3D GUI  130  and when the motion of the hand  122  corresponds to a motion of dragging the web browser UI object  131 , that is, a drag interaction, the interface control apparatus  100  may control the 2D/3D GUI  130  so that the web browser UI object  131  is dragged in a moving direction of the hand  122 . 
     The interface control apparatus  100  may generate the 2D/3D GUI  130  based on the image information. In addition, the interface control apparatus  100  may output the generated 2D/3D GUI  130  to the display apparatus  140 . 
     The display apparatus  140  may include a 2D/3D projector, a 2D/3D TV, and the like. According to an embodiment, the display apparatus  140  may output a 2D/3D image by being input with a 2D/3D image transmission format such as Dual FHD, Side by Side, Up and Down, Horizontal Interlace, Vertical Interlace, and the like. 
       FIG. 2  illustrates a structure of an interface control apparatus  200  according to example embodiments. 
     Referring to  FIG. 2 , the interface control apparatus  200  includes a receiver  201 , a processor  202 , and a control  203 . 
     The receiver  201  receives image information including a depth image related to a user  220  from a sensor  210 . 
     The processor  202  generates at least one of motion information related to a motion of a hand  222  of the user  220  and gaze information related to a gaze  221  of the user  220 , based on the image information. 
     The processor  202  may analyze the received image information, thereby recognizing the motion of the hand  222 , and generate the motion information related to the motion of the hand  222 . 
     Depending on embodiments, the processor  202  may extract information on a posture of the hand  222  from the image information using the mean shift. In addition, the processor  202  may extract information on the posture of the hand  222  from the image information using ADABOOST (ADAPTIVE BOOSTING)-based shape matching which features a hue moment according to a level set. The processor  202  may extract information on a motion path of the hand  222  from the image information using a mean square error (MSE) process. 
     According to an aspect of the invention, the processor  202  may calculate a region of interest (ROI)  250  based on the received image information. In addition, the processor  202  may generate the motion information regarding the motion of the hand  222  within the range of the calculated ROI  250 . 
     The processor  202  may generate the ROI  250  corresponding to the position of the hand  222  when control of a 2D/3D GUI  230  starts. 
     When the same ROI  250  is necessary regardless of a position of the user  220 , the ROI  250  indicates a partial region of the image received from the sensor  210  for generating the motion information regarding the motion of the hand  222 . Depending on embodiments, the processor  202  may not generate the motion information regarding the motion of the hand  222  performed out of the ROI  250 . The ROI  205  will be more specifically explained with reference to  FIG. 3 . 
     In the following description beginning with  FIG. 3 , interface control apparatus  200  of  FIG. 2  is presented as an example embodiment. However, the present invention is not limited to interface control apparatus  200 , as other example embodiments of the interface control apparatus, including interface control apparatus  100  of  FIG. 1  and additional embodiments of the interface control apparatus, could also be used. 
       FIG. 3  illustrates an ROI according to example embodiments. 
     Referring to  FIG. 3 , a hand  312  of a user moves within an ROI  311  in a first case  310  while a hand  322  of a user moves out of an ROI  321  in a second case  320 . 
     In the first case  310 , the interface control apparatus  200  may generate motion information regarding a motion of the hand  312 . For example, the interface control apparatus  200  may analyze the image information, thereby recognizing the hand  312  is moving from the left to the right, and accordingly generate the motion information regarding the motion of the hand  312  moving from the left to the right. 
     In the second case  320 , the interface control apparatus  200  may not generate the motion information regarding a motion of the hand  322 . More specifically, when the interface control apparatus  200  recognizes that the hand  322  is moving out of the ROI  321  as a result of analysis of the image information, the interface control apparatus  200  may not generate the motion information regarding the motion of the hand  322 . In this case, control of the 2D/3D GUI is not performed since there is no motion information. 
     Referring back to  FIG. 2 , the processor  202  may calculate the ROI  250  by calculating a width (ROI width )  251  of the ROI  250  and a height (ROI height )  252  of the ROI  250 . 
     The processor  202  may calculate the width  251  of the ROI  250  using Equations 1. In addition, the processor  202  may calculate the height  252  of the ROI  250  using Equations 2. 
     
       
         
           
             
               
                 
                   
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     D cur  is the distance in centimeter between camera and the user. 
     Image width  and Image height  are the width and the height of the depth image in pixel. 
     FoV width  and FOV height  are the width and the height of the field of view due to the lens of the depth camera. 
     K width  is the average width of ROI window and K height  is the average height of ROI window in the air. 
     According to an aspect of the invention, the processor  202  may calculate a depth difference value between a current frame and at least one previous frame of the depth image, and generate the motion information based on the calculated depth difference value. Hereinafter, generation of the motion information using the depth image will be described in detail with reference to  FIG. 4 . 
       FIG. 4  illustrates a depth image according to example embodiments. 
     Referring to  FIG. 4 , the depth image may include a plurality of frames  411 ,  412 ,  413 , and  414 . A current frame  411  denotes the depth image at a present time ‘t’ whereas at least one previous frame, that is, previous frames  412 ,  413 , and  414  denote the depth image of before the present time ‘t.’ 
     The interface control apparatus  200  may calculate the depth difference value between the current frame  411  and the previous frames  412 ,  413 , and  414 . For example, the interface control apparatus  200  may calculate a first depth difference value between the current frame  411  and the previous frame  412 , calculate a second depth difference value between the current frame  411  and the previous frame  413 , and calculate a depth difference value between the current frame  411  and the previous frame  414 . 
     The interface control apparatus  200  may extract, from the calculated depth difference value, a region of pixels where the depth difference value exceeds a reference value. For example, the interface control apparatus  200  may extract a first region with respect to pixels where the depth difference value exceeds the reference value from the first depth difference value, extract a second region with respect to pixels where the depth difference value exceeds the reference value from the second depth difference value, and extract a third region with respect to pixels where the depth difference value exceeds the reference value from the third depth difference value. 
     When a plurality of regions exist with respect to the pixels where the depth difference value exceeds the reference value, the interface control apparatus  200  may extract pixels  431  forming an intersection from the plurality of regions. For example, the interface control apparatus  200  may extract pixels belonging to all of the first region, the second region, and the third region. 
     The interface control apparatus  200  may generate the motion information by analyzing the pixels forming the intersection. The interface control apparatus  200  may generate the motion information further taking into consideration at least one of an aspect ratio, an image size, and a moment vector direction. For example, when the depth difference is decreasing as a result of analysis of the pixels belonging to all of the first, the second, and the third regions, this means that a distance between the sensor and the user is decreasing. Therefore, the interface control apparatus  200  may recognize a motion of the user, the motion of extending the hand forward, and accordingly generate the motion information regarding the motion. 
     Referring back to  FIG. 2 , the controller  203  controls the 2D/3D GUI  230  based on at least one of the motion information and the gaze information. 
     The 2D/3D GUI  230  may display at least one UI object, for example, UI objects  231 ,  232 , and  233 . 
     In case that the position of the hand  222  corresponds to a position of a motion picture replaying UI object  232  of the 2D/3D GUI  230  and, in addition, the motion of the hand  222  corresponds to a motion of playing the motion picture replaying UI object  232 , that is, a play interaction, the controller  203  may control the 2D/3D GUI  230  such that the motion picture replaying UI object  232  is replayed. 
     The controller  203  may start or end controlling the 2D/3D GUI  230  in accordance with the control start interaction signaling start of the control of the 2D/3D GUI  230  and the control end interaction signaling end of the control of the 2D/3D GUI  230 . 
     In other words, when the motion information corresponds to the control start interaction, the controller  203  may start controlling the 2D/3D GUI  230 . When the motion information corresponds to the control end interaction, the controller  203  may end controlling the 2D/3D GUI  230 . 
     Hereinafter, the control start interaction and the control end interaction will be described in further detail with reference to  FIG. 5 . 
       FIG. 5  illustrates a control start interaction  510  and a control end interaction  520  according to example embodiments. 
     Referring to  FIG. 5 , the control start interaction  510  and the control end interaction  520  are shown in Table  500 . 
     The control start interaction  510  may include at least one of a hand raising motion  511  and a hand extending motion  512  of the user. 
     For example, when the hand raising motion  511  is recognized as a result of analysis of the image information, the interface control apparatus  200  may generate the motion information related to the hand raising motion  511 . Here, since the motion information corresponds to the control start interaction  510 , the interface control apparatus  200  may start controlling the 2D/3D GUI. Depending on embodiments, when the motion information corresponds to the control start interaction  510 , the interface control apparatus  200  may generate the ROI in a position of a hand of the user and start controlling the 2D/3D GUI according to the motion information regarding the hand motion within the ROI. 
     The control end interface  520  may include a hand lowering motion  521  of the user. 
     For example, when the hand lowering motion  512  is recognized as a result of analysis of the image information, the interface control apparatus  200  may generate the motion information related to the hand lowering motion  512 . Here, since the motion information corresponds to the control end interaction  520 , the interface control apparatus  200  may end controlling the 2D/3D GUI. 
     Referring back to  FIG. 2 , the interface control apparatus  200  may further include a database (not shown). 
     The database may store a plurality of interactions for controlling the 2D/3D GUI  230 . 
     When any of the plurality of interactions corresponds to the motion information, the controller  203  may control movement of a control point of the 2D/3D GUI  230  based on the interaction corresponding to the motion information. 
     In addition, when no interaction corresponds to the motion information out of the plurality of interactions, the controller  203  may control the movement of the control point of the 2D/3D GUI  230  based on the motion information. 
     Hereinafter, an interaction according to example embodiments will be described in detail. 
       FIG. 6  illustrates various interactions according to example embodiments. 
     Referring to  FIG. 6 , a plurality of interactions  610 ,  620 ,  630 ,  640 ,  650 , and  660  are illustrated as a table. 
     The plurality of interactions may include at least one of an execution interaction  610 , a cancel interaction  620 , a drag-and-drop interaction  630 , a scrolling interaction  640 , a rotation interaction  650 , and a scaling interaction  660 . 
     The execution interaction  610  may include at least one of a stopped motion  611  wherein a hand of the user stays stopped for a predetermined time (t seconds) and a thumb-up motion  612  wherein the hand is in a thumb-up posture. 
     For example, as a result of analyzing the image information, when the stopped motion  611  of the hand is recognized, the interface control apparatus  200  may generate the motion information related to the stopped motion  611  where the hand stays stopped for the predetermined time. Here, since the motion information corresponds to the execution interaction  610 , the interface control apparatus  200  may control the 2D/3D GUI based on the motion information. Specifically, the interface control apparatus  200  may control the 2D/3D GUI such that a UI object corresponding to the position of the hand, out of at least one UI object on the 2D/3D GUI, is executed. 
     For another example, as a result of analyzing the image information, when the thumb-up motion  612  of the hand is recognized, the interface control apparatus  200  may generate the motion information related to the thumb-up motion  612  where the hand is in the thumb-up posture. Here, since the motion information corresponds to the execution interaction  610 , the interface control apparatus  200  may control the 2D/3D GUI based on the motion information. Specifically, the interface control apparatus  200  may control the 2D/3D GUI such that a UI object corresponding to the position of the hand, out of at least one UI object on the 2D/3D GUI, is executed. 
     According to an embodiment, the cancel interaction  620  may include a thumb-down motion  621  of the hand of the user. 
     For example, as a result of analyzing the image information, when the thumb-down motion  621  of the hand is recognized, the interface control apparatus  200  may generate the motion information related to the thumb-down motion  621  where the hand is in the thumb-down posture. Here, since the motion information corresponds to the cancel interaction  620 , the interface control apparatus  200  may control the 2D/3D GUI based on the motion information. Specifically, the interface control apparatus  200  may control the 2D/3D GUI such that a UI object corresponding to the position of the hand, out of at least one UI object on the 2D/3D GUI, is cancelled. 
     The drag-and-drop interaction  630  may include a series of motions of the hand, that is, a hand closing motion  632 , a closed-hand moving motion, and a hand opening motion  633 . 
     For example, as a result of analyzing the image information, when the series of motions including the hand closing motion  632 , the closed-hand moving motion, and the hand opening motion  633  are recognized, the interface control apparatus  200  may generate the motion information regarding the series of motions. Here, since the motion information corresponds to the drag-and-drop interaction  630 , the interface control apparatus  200  may control the 2D/3D GUI based on the motion information. Specifically, the interface control apparatus  200  may control the 2D/3D GUI such that a UI object  631  corresponding to the position of the hand, out of at least one UI object on the 2D/3D GUI, is moved to where the hand is opened. 
     The scrolling interaction  640  may include a fast hand moving motion  641  wherein the user moves the hand faster than a predetermined reference speed. 
     For example, when the fast hand moving motion  641  is recognized as a result of analyzing the image information, the interface control apparatus  200  may generate the motion information regarding the fast hand moving motion  641  wherein the user moves the hand faster than the reference speed. Here, since the motion information corresponds to the scrolling interaction  640 , the interface control apparatus  200  may control the 2D/3D GUI based on the motion information. Specifically, the interface control apparatus  200  may control the 2D/3D GUI such that a UI object corresponding to the position of the hand, out of at least one UI object on the 2D/3D GUI, is scrolled in a direction of moving the hand. 
     The rotation interaction  650  may include a series of motions of hands of the user, that is, a hands closing motion  652  wherein the user closes both hands and a hands rotating motion  653  wherein the user rotates both closed hands. 
     For example, when the series of motions including the hands closing motion  652  and the hands rotating motion  653  are recognized as a result of analyzing the image information, the interface control apparatus  200  may generate the motion information regarding the series of motions. Here, since the motion information corresponds to the rotation interaction  650 , the interface control apparatus  200  may control the 2D/3D GUI based on the motion information. Specifically, the interface control apparatus  200  may control the 2D/3D GUI such that a UI object  651  corresponding to the position of the hand, out of at least one UI object on the 2D/3D GUI, is rotated by an angle by which the closed hands are rotated. 
     The scaling interaction  660  may include a series of motions of the hands, that is, a hands closing motion  662  wherein the user closes both hands and a hands separating motion  663  wherein the user separates both closed hands from each other. In addition, the scaling interaction  660  may include a series of motions including the hands closing motion  663  and a hands collecting motion wherein the user moves both closed hands toward each other. 
     For example, when the series of motions including the hands closing motion  662  and the hands separating motion  663  or including the hands closing motion  662  and the hands collecting motion are recognized as a result of analyzing the image information, the interface control apparatus  200  may generate the motion information regarding the series of motions. Here, since the motion information corresponds to the scaling interaction  660 , the interface control apparatus  200  may control the 2D/3D GUI based on the motion information. Specifically, the interface control apparatus  200  may control the 2D/3D GUI such that a UI object  661  corresponding to the position of the hand of the user, out of at least one UI object on the 2D/3D GUI, is size-transformed, that is, enlarged or reduced by a distance by which the closed hands are separated or collected. 
     Although the present embodiment has been explained in such a manner that the plurality of interactions include the execution interaction  610 , the cancel interaction  620 , the drag-and-drop interaction  630 , the scrolling interaction  640 , the rotation interaction  650 , and the scaling interaction  660 , the present invention is not limited to the embodiment. 
     Referring back to  FIG. 2 , when the motion information corresponds to a high precision interaction, the controller  203  may display an operation region corresponding to the motion information. In addition, the controller  203  may control the 2D/3D GUI  230  within the operation region. 
     According to an embodiment, the controller  203  may define a control range of the 2D/3D GUI  230  as a predetermined region rather than the entire 2D/3D GUI  230 . Here, the operation region denotes the predetermined region within which the control range is limited. 
     Depending on embodiments, the controller  203  may indicate the operation region by displaying the other region but the operation region in the 2D/3D GUI  230  in a dark color. Alternatively, the controller  203  may indicate the operation region by enlarging the operation region to a predetermined size. 
     The high precision interaction may include a motion of the user  220  of moving both hands to a front of the user  220  and a motion of the user  220  of stopping any one of both hands for longer than a reference time. 
     For example, as a result of analyzing the image information, when the motions including moving both hands to the front of the user  220  and stopping either hand for longer than the reference time are recognized, the processor  202  may generate the motion information regarding the motions. Here, since the motion information corresponds to the high precision interaction, the controller  203  may control the 2D/3D GUI  230 . Specifically, the controller  203  may control the 2D/3D GUI such that a region of the 2D/3D GUI, corresponding to a position of one hand of the user stopped longer than the reference time, is displayed as an adjustment region and that a control point within the adjustment region is moved corresponding to a position of the other hand. 
     Hereinafter, the high precision interaction will be described in detail with reference to  FIG. 7 . 
       FIG. 7  illustrates a fixed interaction according to example embodiments. 
     Referring to  FIG. 7 , in a state  700  before the motion information corresponding to the high precision interaction is recognized, the interface control apparatus  200  may display at least one UI object, for example, UI objects  711 ,  712 , and  713  included in a 2D/3D GUI  710  on a display screen. 
     As a result of analyzing the image information, when the motions of moving both hands  731  and  732  of the user to the front of the user and stopping either hand  731  for longer than the reference time are recognized, the interface control apparatus  200  may generate the motion information regarding the motions. Here, since the motion information corresponds to the high precision interaction, the interface control apparatus  200  may control the 2D/3D GUI  710  based on the motion information. 
     Depending on embodiments, the interface control apparatus  200  may calculate and generate an ROI  720  corresponding to a position of the hand of the user. Here, the high precision interaction may include a motion of the user of moving both hands  731  and  732  into the ROI  720  and a motion of the user of stopping either hand  731  for longer than the reference time. 
     Referring to a state  750  after the motion information corresponding to the high precision interaction is recognized, the interface control apparatus  200  may indicate an operation region  761  corresponding to a position of a stopped hand  781  of both hands  781  and  782 . 
     Here, the interface control apparatus  200  may display the other region except the operation region  761  in a 2D/3D GUI  760  in a dark color. For example, UI objects  762  and  763  located in the other region than the operation region  761  may be displayed in a dark color. 
     In addition, when the operation region  761  is displayed, the interface control apparatus  200  may control the 2D/3D GUI  760  such that a control point is moved corresponding to a movement of the other hand  782  of both hands. 
     Depending on embodiments, the interface control apparatus  200  may display the operation region  761  corresponding to the position of the hand  781  being stopped out of both hands  781  and  782  located in the ROI  770 . 
     Referring back to  FIG. 2 , the processor  202  may generate gaze information regarding the gaze  221  of the user  220  based on the image information. 
     The processor  202  may extract head position information regarding a position of a head of the user  220  and head rotation information regarding rotation of the head, from the image information. Also, the processor  202  may generate the gaze information based on the head position information and the head rotation information. 
     The processor  202  may extract the head position information from the image information using a modified census transform (MCT)-based ADABOOST method. In addition, the processor  202  may extract the head rotation information from the image information using an active shape model (ASM). 
     The controller  203  may control the 2D/3D GUI  230  based on the motion information regarding the hand  222  of the user  220  and the gaze information regarding the gaze  221  of the user  220 . 
     When the gaze  222  of the user  220  corresponds to the position of the motion picture replaying UI object  232  of the 2D/3D GUI  230  and, in addition, the motion of the hand  222  corresponds to the motion of playing the motion picture replaying UI object  232 , that is, the play interaction, the controller  203  may control the 2D/3D GUI  230  such that the motion picture replaying UI object  232  is replayed. 
     A database according to an embodiment may store a plurality of interactions based on the motion information and the gaze information. When any interaction corresponding to the gaze information and the motion information exists among the plurality of interactions, the controller  203  may control the 2D/3D GUI  230  based on the interaction corresponding to the gaze information and the motion information. 
     Hereinafter, the interaction using the gaze  221  of the user  220  will be described in detail with reference to  FIG. 8 . 
       FIG. 8  illustrates an interaction using a gaze of a user according to example embodiments. 
     Referring to  FIG. 8 , a plurality of interactions  810  and  830  using a gaze of a user are illustrated as a table. 
     The plurality of interactions  810  and  830  that uses the gaze of the user may include at least one of a rotation interaction  810  and a scaling interaction  830 . 
     According to an embodiment, the rotation interaction  810  may include a series of motions of the user, that is, a gaze stopping motion of stopping a gaze  821  for a predetermined time, a hands closing motion  823  of closing both hands, and a hands rotating motion  824  of rotating the closed hands. 
     For example, as a result of analyzing the image information, when the series of motions including the gaze stopping motion, the hands closing motion  823 , and the hands rotating motion  824  are recognized, the interface control apparatus  200  may generate the motion information regarding the series of motions. Here, since the motion information corresponds to the rotation interaction  810 , the interface control apparatus  200  may control the 2D/3D GUI based on the motion information. Specifically, the interface control apparatus  200  may control the 2D/3D GUI such that a UI object  822  corresponding to the gaze  821  of the user, out of at least one UI object on the 2D/3D GUI, is rotated by an angle correspond the hands rotating motion  824  of the closed hands of the user. 
     The scaling interaction  830  may include a series of motions of the user, that is, a gaze stopping motion of stopping a gaze  841  for a predetermined time and a hands closing motion  843  of closing both hands, and a hands separating motion  844  of separating the closed hands from each other. Also, the scaling interaction  830  may include a series of motions, that is, the hands closing motion  843  and a hands collecting motion of collecting both hands to each other. 
     For example, as a result of analyzing the image information, when the series of motions including the gaze stopping motion, the hands closing motion  843 , and the hands separating motion  844  or the series of motions including the hands closing motion  843  and the hands collecting motion are recognized, the interface control apparatus  200  may generate the motion information regarding the series of motions. Here, since the motion information corresponds to the scaling interaction  830 , the interface control apparatus  200  may control the 2D/3D GUI based on the motion information. Specifically, the interface control apparatus  200  may control the 2D/3D GUI such that a UI object  842  corresponding to the gaze  841  of the user, out of at least one UI object on the 2D/3D GUI, is size-transformed, that is, enlarged or reduced corresponding to a distance by which the closed hands are separated or collected. 
     Although the plurality of interactions using the gaze of the user, including the rotation interaction  810  and the scaling interaction  830 , have been explained according to an example embodiment, the present invention is not limited thereto. 
     Referring back to  FIG. 2 , when the gaze information and the motion information correspond to the high precision interaction, the controller  203  may display the operation region corresponding to the gaze information and the motion information. Also, the controller  203  may control the 2D/3D GUI within the operation region. 
     The high precision interaction using the gaze  221  of the user  220  may include a motionless gaze stopping motion wherein the user  220  stops the gaze without moving for longer than a reference time. 
     For example, as a result of analyzing the image information, when the motionless gaze stopping motion of the user  220  is recognized, the processor  202  may generate gaze information regarding the motionless gaze stopping motion. Here, since the gaze information corresponds to the high precision interaction, the controller  230  may control the 2D/3D GUI  230 . Specifically, the controller  203  may control the 2D/3D GUI  230  such that a region corresponding to the gaze  221  of the user  220  in the 2D/3D GUI  230  is displayed as an adjustment region and that a control point within the adjustment region is moved corresponding to the position of the hand  222  of the user  220 . 
     Hereinafter, the high precision interaction using the gaze  221  of the user  220  will be described in detail with reference to  FIGS. 9 and 10 . 
       FIG. 9  illustrates a fixed interaction using a gaze of a user according to example embodiments. 
     Referring to  FIG. 9 , in a state  900  before the gaze information and the motion information corresponding to the high precision interaction are recognized, the interface control apparatus  200  may display at least one UI object, for example, UI objects  911 ,  912 , and  913  included in a 2D/3D GUI  910  on a display screen. 
     When a motionless gaze stopping motion wherein a user  920  stops a gaze  921  without moving for longer than a reference time is recognized as a result of analyzing the image information, the interface control apparatus  200  may generate gaze information regarding the motionless gaze stopping motion. Here, since the gaze information corresponds to the high precision interaction, the interface control apparatus  200  may control the 2D/3D GUI  910  based on the gaze information. 
     Referring to a state  950  after the gaze information and the motion information corresponding to the high precision interaction are recognized, the interface control apparatus  200  may display an operation region  961  corresponding to a gaze  971  of a user  970 . Depending on embodiments, the interface control apparatus  200  may display the other region except the operation region  961  in a 2D/3D GUI  960  in a dark color. For example, UI objects  962  and  963  located in the other region except the operation region  961  may be displayed in a dark color. 
     In addition, when the operation region  961  is displayed, the interface control apparatus  200  may control the 2D/3D GUI  960  such that a control point is moved corresponding to a movement of a hand  972  of the user  970 . 
     The interface control apparatus  200  may calculate and generate an ROI  980  in a position of the hand  972 . Also, the interface control apparatus  200  may control the 2D/3D GUI  960  such that a control point within the ROI  980  is moved corresponding to the movement of the hand  972 . 
       FIG. 10  illustrates an operation region according to example embodiments. 
     Referring to  FIG. 10 , an interface control apparatus according to an embodiment may extract a rotation angle of a head  1010  of a user from image information, and calculate central points (x 1 , y 1 , z 1 )  1023  of an operation region  1024  using the rotation angle of the head  1010 . 
     Here, the interface control apparatus  200  may calculate the central points (x 1 , y 1 , z 1 )  1023  of the operation region  1024  using [Equation 3] through [Equation 6] as follows.
 
 d =√{square root over ( x   0   2   +y   0   2   +z   0   2 )}  [Equation 3]
 
     wherein, d( 1031 ) denotes a distance from a display apparatus to the head  1010  of the user. A position of the head  1010  may be denoted by a coordinate value (x 0 , y 0 , z 0 ) with respect to a coordinate axis  1040 .
 
 x   1   =d ×cos( rx )  [Equation 4]
 
 y   1   =d ×cos( ry )  [Equation 5]
 
 z   1   =d ×cos( rz )  [Equation 6]
 
     wherein, rx  1011  denotes a pitch value of the head  1010 , ry  1013  denotes a yaw value of the head  1010 , and a rz  1012  denotes a roll value of the head  1010 . 
     The interface control apparatus  200  may display the operation region by adding predetermined values dx, dy, and dz to the calculated central point (x 1 , y 1 , z 1 )  1023 . 
     Referring back to  FIG. 2 , the interface control apparatus  200  may further include a generator  204  and an outputter  205 . 
     The generator  204  may generate the 2D/3D GUI  230  based on the image information. 
     The outputter  205  may output the 2D/3D GUI  230  to a display apparatus  240 . 
       FIG. 11  illustrates a structure of a generator  1110  of an interface control apparatus according to example embodiments. For example, the generator  1110  may be included in interface control apparatus  200 . 
     Referring to  FIG. 11 , the generator  1110  may include a view point adjustment unit  1120 , a 2D/3D scene rendering unit  1130 , and a 2D/3D GUI generation unit  1140 . 
     The view point adjustment unit  1120  may extract information on positions of a left eye and a right eye of a user, from image information received from a sensor. In addition, the view point adjustment unit  1120  may adjust a position of a left view point corresponding to the left eye position and a position of a right view point corresponding to the right eye position. 
     When a plurality of users exist within a sensing range of the sensor, the view point adjustment unit  1120  may determine whether a main user that inputs a control start interaction exists among the plurality of users. 
     When the main user exists among the plurality of users, the view point adjustment unit  1120  may extract the information on the left eye position and the right eye position of the main user, adjust the left view point position corresponding to the position of the left eye of the main user, and adjust the right view point position corresponding to the position of the right eye of the main user. 
     When the main user does not exist, the view point adjustment unit  120  may extract information on an average position of left eyes of the plurality of users and information on an average position of right eyes of the plurality of users, adjust the left view point position corresponding to the average position of the left eyes, and adjust the right view point position corresponding to the average position of the right eyes. 
     The 2D/3D rendering unit  1130  may render a left 2D/3D scene based on the left view point position. Also, the 2D/3D rendering unit  1130  may render a right 2D/3D scene based on the right view point position. 
     The 2D/3D GUI generation unit  1140  may generate the 2D/3D GUI by combining the rendered left 2D/3D scene and the rendered right 2D/3D scene. 
     Hereinafter, a 2D/3D GUI according to example embodiments of the present invention will be described with reference to  FIGS. 12 and 13 . 
       FIG. 12  illustrates a 2D/3D GUI according to example embodiments. 
     Referring to  FIG. 12 , the 2D/3D GUI may display at least one UI object in at least one method of a 2D/3D cube view  1210 , a 2D/3D thumbnail view  1220 , and a 2D/3D slide view. 
     According to the 2D/3D cube view  1210  method, at least one UI object, for example, UI objects  1211 ,  1212 , and  1213  are displayed in the cube form. The 2D/3D thumbnail view  1220  method may display at least one UI object  1221  in the form of a thumbnail image. The 2D/3D slide view  1230  method may display at least one UI object  1231  in the form of a slide. 
     When motion information corresponding to a view conversion interaction is recognized, the interface control apparatus according to an example embodiment may convert a view type into any one of the 2D/3D cube view  1210 , the 2D/3D thumbnail view  1220 , and the 2D/3D slide view  1230 . The view conversion interaction may be the scaling interaction. 
       FIG. 13  illustrates an operation of an interface control apparatus controlling a 2D/3D GUI in accordance with a position of a user, according to example embodiments. 
     Referring to  FIG. 13 , the interface control apparatus  200  may extract, from image information, information on positions of users  1314 ,  1324 , and  1334  and directions of gazes  1311 ,  1321 , and  1331  of the users  1314 ,  1324 , and  1334 . 
     Here, the interface control apparatus  200  may adjust directions of view points related to 2D/3D GUIs  1310 ,  1320 , and  1330 , based on the information on the directions of the gazes  1311 ,  1321 , and  1331  of the users  1314 ,  1324  and  1334 . 
     For example, when the use  1314  is disposed on the left of a display apparatus  1312  and the gaze  1311  of the user  1314  is directed to the right of the display apparatus  1312 , the interface control apparatus  200  may display a UI object  1313  of the 2D/3D GUI  1310  on the right of the 2D/3D GUI  1310 . 
     When the user  1324  is disposed in front of a display apparatus  1322  and the gaze  1321  of the user  1324  is directed to the front of the display apparatus  1322 , the interface control apparatus  200  may display a UI object  1323  of the 2D/3D GUI  1320  in the center of the 2D/3D GUI  1320 . 
     Additionally, when the user  1334  is disposed on the right of a display apparatus  1332  and the gaze  1331  of the user  1334  is directed to the left of the display apparatus  1332 , the interface control apparatus  200  may display a UI object  1333  of the 2D/3D GUI  1330  on the left of the 2D/3D GUI  1330 . 
       FIG. 14  illustrates a flowchart explaining an interface control method according to example embodiments. 
     Referring to  FIG. 14 , the interface control method receives image information including a depth image related to a user from a sensor, in operation  1410 . 
     The interface control method generates at least one of motion information regarding a hand motion of a user and gaze information regarding a gaze of the user, based on the image information in operation  1420 . 
     The interface control method may recognize the hand motion of the user by analyzing the received image information and accordingly generate the motion information regarding the hand motion. 
     Depending on embodiments, the interface control method may extract information on a position of the hand of the user from the image information using the mean shift. Also, the interface control method may extract information on a posture of the hand from the image information using ADABOOST-based shape matching which features a hue moment according to a level set. The interface control method may extract information on a motion path of the hand from the image information using an MSE. 
     The interface control method may calculate an ROI based on the received image information. In addition, the interface control method may generate information on the hand motion within the calculated ROI. 
     When the same ROI is necessary regardless of a position of the user, the ROI indicates a partial region of the image received from the sensor to generate the motion information regarding the motion of the hand. Depending on embodiments, the interface control method may not generate the motion information regarding the motion of the hand performed out of the ROI. 
     The interface control method may calculate the ROI by calculating a width (ROI width ) and a height (ROI height ) of the 250. 
     The interface control method may calculate a depth difference value between a current frame and at least one previous frame of the depth image, and generate the motion information based on the calculated depth difference value. 
     The interface control method may control the 2D/3D GUI based on the motion information in operation  1430 . 
     The 2D/3D GUI may display at least one UI object. 
     Depending on embodiments, when the hand of the user is disposed corresponding to a position of a motion picture replaying UI object of the 2D/3D GUI according to the motion information and, in addition, the hand motion corresponds to the motion of playing the motion picture replaying UI object, that is, a play interaction, the interface control method may control the 2D/3D GUI such that the motion picture replaying UI object is replayed. 
     The interface control method may start or end controlling the 2D/3D GUI in accordance with a control start interaction signaling start of the control of the 2D/3D GUI and a control end interaction signaling end of the control of the 2D/3D GUI. 
     In other words, when the motion information corresponds to the control start interaction, the interface control method may start controlling the 2D/3D GUI. When the motion information corresponds to the control end interaction, the interface control method may end controlling the 2D/3D GUI. 
     When any interaction of a plurality of interactions corresponds to the motion information, the interface control method 
     When any of the plurality of interactions corresponds to the motion information, the interface control method may control the 2D/3D GUI  230  based on the interaction corresponding to the motion information. 
     In addition, when no interaction of the plurality of interactions corresponds to the motion information, the interface control method may control a movement of a control point of the 2D/3D GUI based on the motion information. 
     When the motion information corresponds to a high precision interaction, the interface control method may display an operation region corresponding to the motion information. In addition, the interface control method may control the 2D/3D GUI within the operation region. 
     The interface control method may define a control region of the 2D/3D GUI as a predetermined partial region rather than the entire 2D/3D GUI. Here, the operation region denotes the predetermined region within which the control range is limited. 
     Depending on embodiments, the interface control method may indicate the operation region by displaying the other region of the 2D/3D GUI but the operation region in a dark color. Alternatively, the interface control method may indicate the operation region by enlarging the operation region to a predetermined size. 
     The high precision interaction may include a motion of the user of moving both hands to a front of the user and a motion of the user of stopping any one of both hands for longer than a reference time. 
     For example, as a result of analyzing the image information, when the motions the user of moving both hands to the front of the user and stopping either hand for longer than the reference time are recognized, the interface control method may generate the motion information regarding the motions. Here, since the motion information corresponds to the high precision interaction, the interface control apparatus  200  may control the 2D/3D GUI based on the motion information. Specifically, the interface control method may control the 2D/3D GUI such that a region of the 2D/3D GUI, corresponding to a position of one hand stopped for longer than the reference time, is displayed as an adjustment region and that a control point within the adjustment region is moved corresponding to a position of the other hand. 
     The interface control method may generate gaze information regarding the gaze of the user based on the image information. 
     The interface control method may extract head position information regarding a position of a head of the user and head rotation information regarding rotation of the head of the user, from the image information. Also, the interface control method may generate gaze information based on the head position information and the head rotation information. 
     The interface control method may extract the head position information from the image information using an MCT-based ADABOOST method. In addition, the interface control method may extract the head rotation information from the image information using an ASM. 
     The interface control method may control the 2D/3D GUI based on the motion information regarding the hand motion of the user and the gaze information regarding the gaze of the user. 
     When the gaze of the user corresponds to a position of the motion picture replaying UI object of the 2D/3D GUI and, in addition, the hand motion corresponds to a motion of playing the motion picture replaying UI object, that is, a play interaction, the interface control method may control the 2D/3D GUI such that the motion picture replaying UI object is replayed. 
     A database according to an embodiment may store a plurality of interactions based on the motion information and the gaze information. When any interaction corresponding to the gaze information and the motion information exists among the plurality of interactions, the interface control method may control the 2D/3D GUI based on the interaction corresponding to the gaze information and the motion information. 
     When the gaze information and the motion information correspond to the high precision interaction using the gaze of the user, the interface control method may display the operation region corresponding to the gaze information and the motion information. Also, the interface control method may control the 2D/3D GUI within the operation region. 
     The high precision interaction using the gaze of the user may include a motionless gaze stopping motion of the user of stopping the gaze for longer than a reference time. 
     For example, when the motionless gaze stopping motion of the user is recognized as a result of analyzing the image information, the interface control method may generate gaze information regarding the motionless gaze stopping motion. Here, since the gaze information corresponds to the high precision interaction, the interface control method may control the 2D/3D GUI. Specifically, the interface control method may control the 2D/3D GUI such that a region corresponding to the gaze of the user in the 2D/3D GUI is displayed as an adjustment region and that a control point within the adjustment region is moved corresponding to the position of the hand of the user. 
     The interface control method may generate the 2D/3D GUI based on the image information. In addition, the interface control method may output the 2D/3D GUI to a display apparatus. 
     The interface control method may extract information on positions of a left eye and a right eye of the user, from the image information received from the sensor. In addition, the interface control method may adjust a position of a left view point corresponding to the left eye position and a position of a right view point correspond the right eye position. 
     When a plurality of users exist within a sensing range of the sensor, the interface control method may determine whether a main user that inputs a control start interaction exists among the plurality of users. 
     When the main user exists among the plurality of users, the interface control method may extract the information on the left eye position and the right eye position of the main user, adjust the left view point position corresponding to the position of the left eye of the main user, and adjust the right view point position corresponding to the position of the right eye of the main user. 
     When the main user does not exist, the interface control method may extract information on an average position of left eyes of the plurality of users and information on an average position of right eyes of the position users, adjust the left view point position corresponding to the average position of the left eyes, and adjust the right view point position corresponding to the average position of the right eyes. 
     The interface control method may render a left 2D/3D scene based on the left view point position. Also, interface control method may render a right 2D/3D scene based on the right view point position. 
     The interface control method may generate the 2D/3D GUI by combining the rendered left 2D/3D scene and the rendered right 2D/3D scene. 
     The above-described example embodiments may be recorded in non-transitory computer-readable media including program instructions to implement various operations embodied by a computer. The media may also include, alone or in combination with the program instructions, data files, data structures, and the like. The program instructions recorded on the media may be those specially designed and constructed for the purposes of the example embodiments, or they may be of the kind well-known and available to those having skill in the computer software arts. Examples of non-transitory computer-readable media include magnetic media such as hard disks, floppy disks, and magnetic tape; optical media such as CD ROM disks and DVDs; magneto-optical media such as optical disks; and hardware devices that are specially configured to store and perform program instructions, such as read-only memory (ROM), random access memory (RAM), flash memory, and the like. The media may be transfer media such as optical lines, metal lines, or waveguides including a carrier wave for transmitting a signal designating the program command and the data construction. Examples of program instructions include both machine code, such as produced by a compiler, and files including higher level code that may be executed by the computer using an interpreter. The described hardware devices may be configured to act as one or more software modules in order to perform the operations of the above-described example embodiments, or vice versa. 
     Although example embodiments have been shown and described, it would be appreciated by those skilled in the art that changes may be made in these example embodiments without departing from the principles and spirit of the disclosure, the scope of which is defined in the claims and their equivalents.