Patent Publication Number: US-2015067603-A1

Title: Display control device

Description:
CROSS-REFERENCE TO RELATED APPLICATIONS 
     This application is based upon and claims the benefit of priority from U.S. Provisional Application No. 61/874,068, filed on Sep. 5, 2013; the entire contents of which are incorporated herein by reference. 
    
    
     FIELD 
     Embodiments described herein generally relate to a display control device. 
     BACKGROUND 
     A known method is to display a solid body having icons on a display screen to make a user select one of the icons, which are used to give various instructions to information devices including computers with displays. The user shows several gestures, or touches the screen display to select an intended icon from the icons. An icon is a small picture or a symbol to depict content or an object to be processed. 
     Since an icon is provided on each of the sides of the solid body, a user performs the following operations: 
     a first operation to change a position of the solid body to see an intended icon of a plurality of icons;
 
a second operation to select the intended icon; and
 
a third operation to execute an application shown by the intended icon.
 
     Using the solid body with icons in the background art, the user has difficulty in changing a position of the solid body freely. The user is normally required to repeat many operations to select the intended icon that is located on the back of the solid body. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
       The accompanying drawings, which are incorporated in and constitute a part of this specification, illustrate embodiments of the invention and together with the description, serve to explain the principles of the invention. 
         FIG. 1  is a block diagram showing a display control device according to a first embodiment. 
         FIG. 2  is a diagram showing a solid body provided with icons according to the first embodiment. 
         FIG. 3  is a diagram showing a position and a pose of a solid body according to the first embodiment. 
         FIGS. 4A to 4C  are diagrams showing first to third gestures according to the first embodiment. 
         FIG. 5  is a diagram showing operation modes of the display control device according to the first embodiment. 
         FIG. 6  is a diagram showing a change in the position and pose of the solid body due to the first gesture according to the first embodiment. 
         FIG. 7A  is a diagram showing an operation to change the pose of the solid body according to the first embodiment. 
         FIG. 7B  is a diagram showing the solid body having a pose that has been changed, according to the first embodiment. 
         FIG. 8  is a flow chart showing a behavior of the display control device according to the first embodiment. 
         FIGS. 9 to 11  are diagrams showing another solid body according to the first embodiment. 
         FIG. 12  is a diagram showing another pose of the solid body according to the first embodiment. 
         FIG. 13  is a diagram showing a solid body provided with icons according to a second embodiment. 
         FIG. 14  is a diagram showing the solid body having a pose that has been changed, according to the second embodiment. 
         FIG. 15  is a diagram showing another solid body provided with icons according to the second embodiment. 
         FIG. 16A  is a diagram showing an operation to change the pose of the solid body according to a third embodiment. 
         FIG. 16B  is a diagram showing the solid body having a pose that has been changed, according to the third embodiment. 
         FIG. 17  is a diagram showing a three-dimensional grid where a plurality of solid bodies is stored according to a fourth embodiment. 
         FIGS. 18A and 18B  are diagrams showing a real space and a virtual space according to the fourth embodiment. 
         FIG. 19  is a block diagram showing a function of the display control device according to the fourth embodiment. 
         FIG. 20  is a block diagram showing a sequence of the display control device according to the fourth embodiment. 
         FIG. 21  is a diagram showing state transitions of the display control device according to the fourth embodiment. 
     
    
    
     DETAILED DESCRIPTION 
     According to one embodiment, a display control device includes a display, an object detector, and an arithmetic processor. The display receives information including a position and a pose of a solid body and displays the solid body. The solid body has a plurality of surfaces, at least two or more of the plurality of the surfaces each corresponding to an application. The object detector detects a gesture of a person to determine which one of a first gesture, a second gesture, and a third gesture. The first gesture is to change the position and pose of the solid body. The second gesture is to run the application. The third gesture is to initialize the position and pose of the solid body. The arithmetic processor delivers first information, second information, or third information to the display. The first information is to change the position and pose of the solid body according to the first gesture. The second information is to execute a specific application corresponding to a specific surface of the surfaces according to the second gesture. The third information is to initialize the position and pose of the solid body according to the third gesture. 
     An embodiment will be described below with reference to the drawings. Wherever possible, the same reference numerals will be used to denote the same or like portions throughout the drawings. The same description will not be repeated. 
     First Embodiment 
     A display control device in accordance with a first embodiment will be described with reference to  FIGS. 1 to 8 .  FIG. 1  is a block diagram showing a display control device.  FIG. 2  is a diagram showing a solid body provided with icons.  FIG. 3  is a diagram showing a position and a pose of the solid body.  FIGS. 4A to 4C  are diagrams showing first to third gestures.  FIG. 5  is a diagram showing operation modes of a display control device.  FIG. 6  is a diagram showing a change in the position and pose of the solid body due to the first gesture.  FIG. 7A  is a diagram showing an operation to change the pose of the solid body.  FIG. 7B  is a diagram showing the solid body having a pose that has been changed.  FIG. 8  is a flow chart showing a behavior of the display control device. 
     As shown in  FIG. 1 , a display control device  10  includes a display  11  with a screen, an object detector  12 , and an arithmetic processor  13 . 
     The display  11  receives information Inf1 showing a position and a pose of a solid body  14  from the arithmetic processor  13  to three-dimensionally display the solid body  14  on the screen. The solid body  14  is assigned with a plurality of applications. The solid body  14  is a cube, for example. Hereinafter, the solid body  14  will be referred to as a cube  14 . 
     The object detector  12  includes a stereo camera  15 , a camera controller  16 , and an image processor  17 . The stereo camera  15  detects motion of a hand (object) of a person. The stereo camera  15  fundamentally includes two cameras  15   a  and  15   b.    
     Two lenses are aligned at a regular interval in the stereo camera  15  to thereby reproduce binocular disparity due to subtly different angles of the lenses. Thus, the size of the hand of the person and a distance to the hand are sensed to determine the motion of the hand in a front-back direction toward the stereo camera  15 . 
     The camera controller  16  receives commands from the arithmetic processor  13  to control the stereo camera  15 . The camera controller  16  instructs the stereo camera  15  to set shooting conditions including shooting durations, and start and stop of shooting. 
     The image processor  17  receives image data from the stereo camera  15  to detect an object by pattern recognition. The image processor  17  analyses a motion of a human hand to determine first to third gestures. 
     The first gesture is to change a display position and a pose of the cube  14 . The second gesture is to execute applications that correspond to the respective surfaces of the cube  14 . The third gesture is to initialize a state of the cube  14 . The image processor  17  notifies the arithmetic processor  13  of a determined result. 
     The arithmetic processor  13  has a microprocessor  18  and a memory  19 . The microprocessor  18  executes processing in accordance with the determined result. The memory  19  stores various programs and various data, etc., which are necessary to operate the image processor  17  and the microprocessor  18 . The memory  19  employs a nonvolatile semiconductor memory, for example. 
     When the first gesture is detected, the microprocessor  18  delivers the information Inf1 to the display  11  to change the position and pose of the cube  14  in accordance with the motion of the human hand. 
     When the second gesture is detected, the microprocessor  18  selects a surface having an apparently largest area among the surfaces of the cube  14  to deliver a command to a personal computer, etc., via a communication system. The command instructs a personal computer to execute an application corresponding to the selected surface. 
     When the third gesture is detected, the microprocessor  18  delivers information to the display  11  so as to return the position and pose of the cube  14  to an initial state of the cube  14 . The microprocessor  18  delivers a command for stopping a running application to the personal computer, etc., through the communications system  20 . 
     As shown in  FIG. 2 , the cube  14  has six surfaces  14   a ,  14   b ,  14   c ,  14   d ,  14   e , and  14   f . One application corresponds to each of the surfaces  14   a  to  14   f  of the cube  14 . The surfaces  14   a  to  14   f  of the cube  14  each have an icon showing a corresponding application. Icons will express processing contents or objects in a small picture, a symbol or the like. 
     An application to connect a computer to the internet corresponds to the surface  14   a , and is provided with an icon  31 , for example. An application to perform an electronic mail and schedule control corresponds to the surface  14   b , and is provided with an icon  32 . An application to access a social network service (SNS) corresponds to the surface  14   c , and is provided with an icon  33 . 
     The cube  14  has up to three icons that can be simultaneously seen. The remaining three icons cannot be seen. Changing the pose of the cube  14  enables it to see the remaining three icons. 
     As shown in  FIG. 3 , the position of the cube  14  is expressed by a position vector (x, y, z) in absolute coordinates. The pose of the cube  14  is expressed by a rotation vector (Rx, Ry, Rz) around coordinate axes in model coordinates. 
     The absolute coordinates have an original point at a given point, an X-axis in a lateral direction in the screen, a Y-axis in a longitudinal direction in the screen, and a Z-axis in a direction vertical to the screen. The model coordinates have an original point at the center (not shown) of gravity of the cube  14 . The model coordinates have an Xm-axis, a Ym-axis, and a Zm-axis, which are parallel to the X-axis, the Y-axis, and the Z-axis, respectively. 
     A position vector (x, y, z) is defined by a distance and a direction between the center of gravity of the cube  14  and the original point of the absolute coordinates. A rotation vector (Rx, Ry, Rz) is defined by rotation angles Rx, Ry, and Rz around the Xm-axis, the Ym-axis, and the Zm-axis, respectively. The rotation vector (Rx, Ry, Rz) corresponds to rolling, pitching, and yawing, respectively. 
     Determining six parameters (x, y, z, Rx, Ry, Rz) enables it to manipulate the position and pose of the cube  14 . Present values of the position and pose of the cube  14  are assumed as (xi, yi, zi, Rxi, Ryi, Rzi), and variations in the position and pose of the cube  14  are assumed as (Δx, Δy, Δz, ΔRx, ΔRy, ΔRz). 
     Since the object detector  12  detects a three-dimensional motion of an object, the variations in the position and pose of the cube  14  are determined, e.g., in accordance with a difference of object image data acquired every sampling period. 
     Adding the variations in the position and pose of the cube  14  to the present values of the position and pose of the cube  14  enables the present values of the position and pose of the cube  14  to be updated. The updated present values of the position and pose of the cube  14  are expressed by (x i =x i-1 +Δx, y i =+y i-1 +Δy, z i =z i-1 +Δz, Rx i =Rx i-1 +ΔRx, Ry i =Ry i-1 +ΔRy, Rz i =Rz i-1 +ΔRz). 
     In a first motion, the arithmetic processor  13  computes variations in the position and pose of the cube  14 , updates present values of the position and pose of the cube  14 , and delivers the updated present values to the display  11 . 
     In a third motion, the arithmetic processor  13  reads out initial values of the position and pose of the cube  14  from the memory  19  to deliver the initial values to the display  11 . 
     The first to third gestures will be described below.  FIG. 4A  is a diagram showing a first gesture  42  that means an operating command.  FIG. 4B  is a diagram showing a second gesture  43  that means a Determination/ON command.  FIG. 4C  is a diagram showing a third gesture  44  that means an Open/OFF command. 
     As shown in  FIG. 4A , the first gesture  42  is expressed by opening a thumb, a forefinger, and a middle finger such that the thumb, the forefinger, and the middle finger bisect each other at right angles. The first gesture  42  is the same as the pose showing a Fleming&#39;s right-hand rule. 
     As shown in  FIG. 4B , a second gesture  43  is expressed by a fist. As shown in  FIG. 4C , a third gesture  44  is expressed by opening a hand. 
     An operation mode of the display control device  10  will be described below. As shown in  FIG. 5 , the display control device  10  has three operation modes of IDLE, SELECT, and EXEC. In IDLE, the cube  14  is displayed in an initial state, and IDLE is waiting for the first gesture  42  of a user. In SELECT, the user can freely change the position and pose of the cube  14 , and SELECT is waiting for the second and third gestures  43 ,  44  of the user. In EXEC, an application is in execution, and EXEC is waiting for the first and third gestures  42 ,  44  of the user. 
     When the first gesture  42  is detected at IDLE, the operation mode transits to SELECT. The operation mode transits from SELECT to EXEC and IDLE when the second and third gestures  43  and  44  are detected, respectively. The operation mode transits from EXEC to IDLE and SELECT when the third and first gestures  44 ,  42  are detected, respectively. 
     In SELECT, an operation command enables a user to freely change the position and pose of the cube  14  as many times as the user wants and to thereby execute a Determination/ON command and an Open/OFF command. The Determination/ON command causes an application to be executed. The application corresponds to an icon assigned to a surface with the largest apparent area among the surfaces of the cube  14 . The Open/OFF command causes the position and pose of the cube  14  to be initialized. 
     In EXEC, the Open/OFF command causes the application in execution to be stopped and subsequently the position and pose of the cube  14  to be initialized. 
     Changing the position and pose of the cube  14  will be described below. In SELECT, the position and pose of the cube  14  will be changed by moving and rotating the first gesture  42 . 
     As shown in  FIG. 6 , a lying person (object)  40  faces a screen that displays the cube  14 . The person  40  raises a hand  40   a  of the person  40  and makes the first gesture  42  in order to manipulate the cube  14 . 
     The object detector  12  detects the first gesture  42  to notify the arithmetic processor  13  of the first gesture  42  detected. The arithmetic processor  13  instructs the display  11  to display a maniform pointer  41  on the screen in order to show that the gesture  42  has been detected. The pointer  41  is in touch with the cube  14 . 
     The person  40  moves and rotates the hand  40   a  by the first gesture  42 . The person  40  is able to move the hand  40   a  from side to side, up and down, and back and forth, and also rotate the hand  40   a  back and forth, to right and left, and in a plane. 
     For example, motions to move the hand  40   a  from side to side, up and down, and back and forth are made to correspond to motions of the cube  14  in the X-direction, the Y-direction, and the Z-direction. Motions to rotate the hand  40   a  back and forth, to right and left, and in a plane are made to correspond to the rotations Rx, Ry, and Rz around the coordinate axes in the model coordinates. 
     When the hand  40   a  is waved leftward (rightward), the cube  14  moves in a −X-axis (+X-axis) direction on the screen. When the hand  40   a  is waved upward (downward), the cube  14  moves in a +Y-axis (−Y-axis) direction on the screen. When the hand  40   a  is waved forward (backward), the cube  14  moves in a +Z-axis (−Z-axis) direction on the screen. 
     When the hand  40   a  is rotated forward (backward), the cube  14  rotates in a +Rx (−Rx) direction on the screen. When the hand  40   a  is rotated leftward (rightward), the cube  14  rotates in a −Ry (+Ry) direction on the screen. When the hand  40   a  is rotated leftward (rightward) in a XY plane, the cube  14  rotates in a +Rz (−Rz) direction on the screen. A direction of a rotation vector is defined as being positive when the rotation is counterclockwise. 
     Moving or rotating the hand  40   a  by the first gesture  42  prevents the position and pose of the cube  14  from being changed unintentionally. Moving and rotating the hand  40   a  by any gestures other than the first gesture  42  are not capable of changing the position and pose of the cube  14 . 
       FIG. 7A  is a diagram showing the cube  14  before the cube  14  changes the pose thereof.  FIG. 7B  is a diagram showing the cube  14  after the cube  14  has changed the pose thereof. As shown in  FIG. 7A , the pointer  41  is in touch with the cube  14 . When the person  40  rotates the hand  40   a  counterclockwise around Ym-axis, the cube  14  rotates in a −Ry direction in response to the rotation of the hand  40   a.    
     A rotation angle of the hand  40   a  does not necessarily correspond one-to-one to the rotation angle of the cube  14 . When the rotation of the hand  40   a  is detected, the cube  14  may be controlled such that the cube  14  rotates by an angle of 90°. 
     As shown in  FIG. 7B , the cube  14  rotates only by an angle of 90° clockwise, for example. As a result, the surface  14   a  disappears, and the surface  14   f  which has hidden appears. An application of a weather forecast is assigned to the surface  14   f , for example, and an icon  34  is provided to the surface  14   f . As shown in  FIGS. 7A and 7B , the icon  33  provided to the surface  14   c  has already changed the direction of the icon  33  by 90°. 
     Parameters of the cube  14  are expressed as (x, y, z, Rx, Ry+90, Rz) subsequent to the change in the pose of the cube  14 , provided that the parameters of the cube  14  are expressed as (x, y, z, Rx, Ry, Rz) prior to the change in the pose of the cube  14 . Only Ry has changed. 
     The person  40  moves the hand  40   a  by the first gesture  42  to control the pose of the cube  14  such that an icon corresponding to an application that the person  40  wants to execute faces the person  40 . A surface provided with the icon facing the person  40  has a largest apparent area among the surfaces of the cube  14 . 
     Operation of the display control device  10  mentioned above will be described with reference to a flow chart. As shown in  FIG. 8 , the cube  14  provided with icons is shown in an initial state on the screen, and the operation mode of the cube  14  is set to IDLE. 
     Once a hand gesture of the person  40  is detected (Step S 02 ), what the gesture is and the operation mode for the gesture are determined (Steps S 03 , S 05 , S 07 , S 09 , S 10 ), processing is performed (Steps S 04 , S 06 , S 08 ) in response to what the gesture is and the operation mode, and the processing ends to return to Step  02 . 
     When the operation mode is IDLE or SELECT and the gesture corresponds to the first gesture  42  (YES at Step S 03 ), the operation mode transits from IDLE to SELECT or maintains SELECT to change the position and pose of the cube  14  (Step S 04 ). 
     When the operation mode is SELECT and the gesture corresponds to the second gesture  43  (YES at Step S 05 ); the operation mode transits from SELECT to EXEC to execute an application (Step S 06 ). 
     When the operation mode is EXEC and the gesture corresponds to the first gesture  42  (YES at Step S 07 ); the operation mode transits from EXEC to SELECT to change the position and pose of the cube  14  (Step S 08 ). 
     When the operation mode is EXEC and the gesture corresponds to the second gesture  43  (YES at Step S 09 ); the operation mode returns to Step S 01 . When the operation mode is in SELECT and the gesture corresponds to the third gesture  44  (YES at Step S 10 ); the operation mode goes to Step S 01 . 
     The first to third gestures  42 ,  43 ,  44  enable it to execute an application by intuitively selecting an intended icon from a plurality of icons through less movement. 
     As described above, the display control device  10  of the embodiment displays the cube  14  on the screen thereof. The cube  14  has a plurality of surfaces and at least two of the surfaces are assigned with icons corresponding to applications. The object detector  12  detects a shape of the hand  40   a  of the person  40  to determine one of the first to third gestures  42 ,  43 ,  44 . The arithmetic processor  13  performs processing in accordance with the operation mode and the first to third gestures  42 ,  43 ,  44 . 
     As a result, an intended icon out of a plurality of icons is intuitively selected through less movement, and an application corresponding to the intended icon is executed. 
     Although the solid body  14  has been described as a cube, the solid body  14  may be a polyhedron, each surface of which preferably has the same area. Alternatively, the solid body  14  may be a sphere. 
       FIG. 9  is a diagram showing a solid body  50  that is an icosahedron. The solid body  50  consists of 20 regular triangles. Each of the triangles of the solid body  50  is provided with an icon. 
       FIG. 10  is a diagram showing a soccer-ball-shaped solid body  52 . The solid body  52  consists of 12 regular pentagons and 20 regular hexagons. Five regular hexagons are arranged so as to surround one regular pentagon. Surfaces of the solid body  52  are each provided with an icon. 
     It could be difficult to intuitively select which surface is apparently the largest, because the regular hexagon and regular pentagon have areas different from each other. It is appropriate to make an icon, which is provided to a centrally visible surface, responsive to an executed icon. 
       FIG. 11  is a diagram showing a spherical solid body  54 . The spherical solid body  54  has a plurality of spherical surfaces  54   a  each having the same area. The spherical surfaces  54   a  are each provided with one icon. 
     All the surfaces of the solid bodies  50 ,  52 ,  54  shown in  FIGS. 9 to 11  are not necessarily provided with one icon. Just a required number of icons should be provided. 
     As described above, when the operation mode is in SELECT and the second gesture  43  indicating a Determination/ON command is detected, an application is executed corresponding to an icon provided onto a largest apparent surface among the surfaces of the solid body. However, depending on the pose of the solid body, a plurality of largest apparent surfaces could be present in some cases. 
       FIG. 12  is a diagram showing a pose of the solid body  14  where a plurality of largest apparent surfaces are present on the solid body  14 . As shown in  FIG. 12 , when the person  40  looks straight at a straight line passing through the center of gravity (not shown) of the solid body  14  and a corner  14   g  (an intersection of three adjacent surfaces  14   a ,  14   b ,  14   c ) of the solid body  14 ; the three adjacent surfaces  14   a ,  14   b ,  14   c  seem to have the same size. 
     The plurality of the largest apparent surfaces prevents one icon from being selected, so that no application is executed. Alternatively, whenever the person  40  selects one of the icons on the adjacent surfaces  14   a ,  14   b ,  14   c ; an application corresponding to the icon selected by the person  40  may be executed. 
     As described above, only one solid body is displayed on the screen, but the number of solid bodies displayed on the screen is not particularly limited. Alternatively, a plurality of solid bodies may be displayed on the screen. 
     As described above, the hand  40   a  of the person  40  is detected with the stereo camera  15 . Alternatively, the hand  40   a  may be detected by combining a camera and a distance meter. Distance meters include an ultrasonic distance meter, a laser distance meter, and a microwave distance meter. Alternatively, a three-dimensional depth sensor described later may be used. 
     Although changing the position and pose of the solid body has been described above, the size or color of the solid body may be changed. For example, the solid body is displayed in a small size and paled out initially. Once a movement of the solid body is detected, the solid body is displayed in a large size and in bright colors. Thus, visibility and operability of the solid body are enhanced on the screen. 
     Second Embodiment 
     A display control device in accordance with a second embodiment will be described with reference to  FIGS. 13 and 14 . FIG.  13  is a diagram showing a solid body provided with an icon.  FIG. 14  is a diagram showing the solid body in which the pose of the solid body has been changed. 
     Wherever possible, the same reference numerals will be used to denote the same or like portions throughout the drawings in the second embodiment. The same description will not be repeated in the detailed description. The second embodiment differs from the first embodiment in that the solid body is translucently displayed. 
     As shown in  FIG. 13 , a solid body  60  of the embodiment is disk-shaped. The solid body  60  will be referred to as a coin  60 . The coin  60  has a first surface  60   a  and a second surface  60   b , both being parallel to each other, and a side surface  60   c . The coin  60  is displayed on the screen such that the coin  60  is in a position and a pose, both the position and the pose showing the first surface  60   a  and a portion of the side surface  60   c , hiding the second surface  60   b.    
     Displaying the coin  60  translucently enables it to see the second surface  60   b , which should be hidden, through the first surface  60   a  and the side surface  60   c.    
     The first surface  60   a  is provided with an icon  61 . The second surface  60   b  is provided with an icon  62 . The side surface  60   c  is provided with no icon. The icon  62  provided on the second surface  60   b  is seen through the first surface  60   a  and the side surface  60   c . The front icon  61  is displayed deeply and the icon  62  on the back surface is displayed thinly. 
     The icon  61  corresponds to, e.g., an application that controls sound volume. The icon  62  corresponds to, e.g., an application that controls brightness of the screen. 
       FIG. 13  shows that the front icon  61  is under being selected. The sound volume is controlled by turning the coin  60  around the Zm-axis. Black dots  61   a ,  61   b  show turning directions to turn up and turn down the sound volume respectively. A triangle  63  appears above the coin  60 , and does not move when the coin  60  rotates around the Zm-axis. A position of the triangle  63  shows to what extent the coin has been turned to control the sound volume. 
     When the coin  60  receives an instruction to rotate around the Zm-axis to thereby exceed the range from the black dot  61   a  to the black dot  61   b , the instruction is made to be invalid and the coin rotates no more. The rotatable range of the coin is defined as the range from a point where the triangle  63   a  meets the black dot  61  to another point where the triangle  63  meets the black dot  61   b.    
     When the gesture  43  corresponding to the Determination/ON command is detected, the application for adjusting the sound volume is executed so that the sound volume is adjusted by the point of the coin  60  denoted by the triangle  63 . When the application requires an input of a sound volume, the coin  60  is rotated to input the sound volume in the same way as an analog device. 
     As shown in  FIG. 14 , an application for adjusting brightness is executed by inverting the two sides of the coin  60 . The surface  60   b  that was the rear side of the coin  60  becomes a new front side to be provided with an icon  61 , and the surface  60   a  that was the front side of the coin  60  becomes a new rear side of the coin  60 . The icon  62  on the front side is deeply displayed and the icon  61  on the rear side is thinly displayed. 
     The position and pose of the coin  60  are expressed by a position vector (x, y, z) in an absolute coordinate, and a rotation vector (Rx, Ry, Rz) around a model-coordinate axis as well as in  FIG. 3 . The position and pose of the coin  60  are changed in accordance with a motion of the first gesture  42  as well as in  FIG. 6 . 
     Once the gesture  43  corresponding to a Determination/ON command is detected, an application for adjusting brightness is executed to set the brightness specified by the triangle  63 . 
     As described above, since the coin  60  is displayed translucently, the icon  62  on the second surface  60   b  that is normally invisible can be seen through the first surface  60   a  and the side surface  60   c . It is therefore easy to look for a desired icon. 
     As described above, the solid body is translucently displayed with a coin, but the shape of the solid body is not limited in particular.  FIG. 15  is a diagram showing a solid body of triangular pyramid, the triangular pyramid having four regular triangles of equal size. 
     As shown in  FIG. 15 , the triangular pyramid  70  has the three sides  70   a ,  70   b ,  70   c , and a bottom  70   d . The triangular pyramid  70  is displayed on the screen as follows. The two sides  70   a ,  70   b  can be seen while the side  70   c  and the bottom  70   d  cannot be seen on the screen. 
     Since the triangular pyramid  70  is displayed translucently, the side  70   c  and the bottom  70   d  can be seen through the two sides  70   a ,  70   b . An icon  33  is provided onto the side  70   a , for example. An icon  31  is provided onto the side  70   b , for example. An icon  34  is provided onto the side  70   c , for example. An icon  32  is provided onto the bottom  70   d , for example. 
     The icons  34  and  32  provided on the side  70   c  and the bottom  70   d , respectively, can be seen through the sides  70   a  and  70   b . It is therefore easy to look for a desired icon. 
     As shown in  FIG. 4B , once the gesture corresponding to a Determination/ON command is detected, an application corresponding to the icon  31  provided onto the surface  70   b  with a largest apparent area is executed. 
     Alternatively, the solid bodies  14 ,  50 ,  52 ,  54 , which are shown in  FIGS. 2 ,  9 ,  11 , may be displayed translucently. The icons on the rear side could be hidden to be invisible by the icon on the front side in the solid bodies  50 ,  52 , and  54 , all of which have a plurality of surfaces. Providing icons dispersively on some of the surfaces are better than providing one icon on every surface in the solid bodies  50 ,  52 ,  54 , all of which have a plurality of surfaces. 
     Third Embodiment 
     A display control device in accordance with a third embodiment will be described with reference to  FIGS. 16A and 16B .  FIG. 16A  is a diagram showing operation of changing a pose of a solid body.  FIG. 16B  is a diagram showing a solid body which has a changed pose. 
     Wherever possible, the same reference numerals will be used to denote the same or like portions throughout the drawings in the third embodiment. The third embodiment differs from the first embodiment in that the third embodiment includes a touch screen. 
     As shown in  FIGS. 16A and 16B , the display control device  80  of the embodiment is built into apparatuses, which includes a mobile phone terminal and a tablet terminal. A display of the display control device  80  includes a touch screen  81 . A menu button  82  is provided below the display. 
     The cube  14  is displayed on the touch screen  81 . The position and pose of the cube  14  will be changed by a first motion as follows. Slow movement of a finger changes a position vector (x, y, z), and fast movement of the finger changes a rotation vector (Rx, Ry, Rz). 
     The finger in touch with the touch screen  81  is moved in any one direction of the X-direction, the Y-direction, and a diagonal direction with respect to the X-direction and the Y-direction at a first velocity. When the finger is moved in the X-direction, a position vector (x) is changed. When the finger is moved in the Y-direction, a position vector (y) is changed. When the finger is moved in the diagonal direction, a position vector (z) is changed. 
     A finger is moved in any one direction of the X-direction, the Y-direction, and the diagonal direction at a second speed higher than the first speed. Moving the finger in the X-direction changes the rotation vector (Rx). Moving the finger in the Y-direction changes the rotation vector (Ry). Moving the finger in the diagonal direction changes the rotation vector (Rz). 
     As shown in  FIG. 16A , when a finger  83  gets in touch with the cube  14  displayed on the touch screen  81  and moves in the X-direction quickly (at the second velocity); the cube  14  rotates in the −Ry-direction on the touch screen  81 . The moving distance of the finger  83  does not necessarily correspond one-to-one to the rotation angle of the cube  14 . Whenever a quick movement of the finger  83  is detected, the cube  14  may rotate by 90° in response to the quick movement. 
     As shown in  FIG. 16B , the cube  14  clockwise rotates only by 90°, for example. The side  14   a  that has been visible becomes invisible, and the side  14   f  that has been invisible becomes visible. 
     Double-clicking or double-tapping the touch screen  81 A performs a second motion to execute applications corresponding to the icons provided to the cube  14 . An application is executed, which corresponds to the icon provided on a side with an apparently largest area among a plurality of sides. 
     Pursing fingers in touch with the touch screen  81  performs a third motion to return the cube  14  to an initial state thereof. 
     As described above, the display control device  80  of the embodiment has the touch screen  81 . A specific motion of the fingers on the touch screen  81  is detected to determine to which motion of first to third motions the specific motion corresponds. The display control device  80  of the embodiment is suitable for devices including mobile communication terminals, tablet devices, head-mounted displays, and notebook computers. 
     Although the first to third motions have been described as being performed only by motions of fingers, a menu button  82 , the touch screen  81 , and a screen keyboard on the touch screen  81  may be used together with the first to third motions. A keyboard and a mouse are used for a notebook computer. 
     Fourth Embodiment 
     A display control device in accordance with a fourth embodiment will be described with reference to  FIGS. 17 to 21 .  FIG. 17  is a diagram showing a three-dimensional grid where a plurality of solid bodies is stored.  FIGS. 18A and 18B  are diagrams showing real space and virtual space.  FIG. 19  is a block diagram showing a function of the display control device.  FIG. 20  is a diagram showing sequence of the display control device.  FIG. 21  is a diagram showing a transition state of the display control device. 
     Wherever possible, the same reference numerals will be used to denote the same or like portions throughout the drawings in the fourth embodiment. The same description will not be repeated in the detailed description. The fourth embodiment differs from the first embodiment in that a plurality of solid bodies has been stored in a three-dimensional grid. 
     As shown in  FIG. 17 , a three-dimensional grid  90  is displayed on the screen of the display control device of the embodiment. The solid bodies are displayed at a position and a pose on the screen such that each of the solid bodies is stored at the position, which is preliminarily designated in the grid. 
     The three-dimensional grid  90  is has 2×2×2 cells, for example. The three-dimensional grid  90  can store up to eight solid bodies. The solid bodies in the grid  90  are preferably polyhedrons different from each other. For example, a regular icosahedron is stored in a cell  90   a . The coin  60  is stored in a cell  90   b . The cube  14  is stored in a cell  90   c . A regular dodecahedron is stored in a cell  90   d.    
     Storing a plurality of solid bodies in the three-dimensional grid  90  enables it to compactly display a plurality of solid bodies. 
     The three-dimensional grid  90  is defined to detect a motion of an object using a three-dimensional depth sensor. The three-dimensional depth sensor irradiates the object with an infrared dot pattern to determine a three-dimensional position and an irregularity of the object in accordance with a spatial difference between the dot pattern reflected from the object and the dot pattern reflected from a background. 
     Specifically, the three-dimensional depth sensor has an ordinary visible light camera, an infrared projector, and an infrared camera. The infrared projector and the infrared camera are arranged on the both sides of the visible light camera. 
     The infrared projector irradiates an object with the infrared dot pattern. An infrared camera takes a picture of the infrared dot pattern reflected from the object, and the infrared dot pattern reflected from the background of the object, e.g., walls. 
     Since the infrared projector and the infrared camera are horizontally located away from each other, the infrared camera can see a shadow of the object. The infrared dot pattern is widely-spaced in an area where the shadow of the object is made, and is narrowly-spaced on the opposite side of the area. It should be noted that the larger a distance difference between the widely-spaced dot pattern and the narrowly-spaced dot pattern, the nearer the object is. 
     As shown in  FIG. 18A , a real space  92 , which enables the three-dimensional depth sensor  91  to be operable, has an angular field that is horizontally 72° and vertically 58°, and an effective distance of 25 cm to 50 cm. A cube  93  is defined in the real space  92  in advance. 
     As shown in  FIG. 18B , the three-dimensional grid  90  is made up of line segments forming the cube  93  defined in the real space  92  and additional line segments  94  in a virtual space  95 . The additional line segments  94  divide the cube  93  into predetermined cells of the three-dimensional grid  90 . 
     Operation of the display control device of the embodiment will be described from a functional viewpoint. As shown in  FIG. 19 , a system  100  includes a detector  101 , a command interface (referred to as command IF) unit  102 , a GUI (Graphical User Interface) unit  103 , and App-exe (Application execute) unit  104 . 
     A user can see a detected finger or hand as a pointer in the virtual space  95 . When a solid body in a cell pointed by the user is selected by a gesture of the user, a position and a pose of the solid body is changed by the gesture of the user. 
     An OFF gesture  44  of the user returns the selected solid body to the original position in the cell. A determination gesture  43  of the user causes GUI to run an application corresponding to an icon having an apparently largest area. 
       FIG. 20  is a diagram showing a sequence of this scenario. A principal portion of this scenario will be described. As shown in  FIG. 20 , the detector  101  receives image data of a user&#39;s gesture (S 1 ) to output a detected position and an attribute of the user, which relates to a finger or a hand (S 2 ). The command IF unit  102  receives the detected position and attribute of the user to output an analyzed gesture command and a position and a rotation of the gesture command (S 3 ). The GUI unit  103  receives the position and rotation of the gesture command to display what to display as GUI (S 4 ). 
     The GUI unit  103  delivers an output to prompt the execution or stop of an application selected by inputting the position and rotation of the gesture command (S 5 ). The App-exe unit  104  receives the output to execute or stop the application selected and to subsequently notify the user of the output showing the execution or stop of the application (S 6 ). 
     The GUI unit  103  outputs the position of the gesture command by the position and rotation of the gesture command (S 7 ). The App-exe unit  104  operates the application by the inputting of the command and position from the GUI unit  103  to notify the user of an operation result (S 8 ). 
     As shown in  FIG. 21 , GUI is in IDLE as an initial state. Each definition of cells included in the three-dimensional grid  90  is given to the three-dimensional grid  90  from a file, and a solid body is given a definition of the position and pose of the solid body from the file so that GUI displays the solid body on the screen. 
     When “Operation Command” (the first gesture  42 ) and “position information of a hand in the three-dimensional grid  90 ” are detected at IDLE, the operation mode transits to SELECT. 
     When “Operation Command,” “Rotation Information” (Δ Rx, Δ Ry, Δ Rz), and “Position Information” (Δ x, Δ y, Δ z) are detected at SELECT, the position and pose of the solid body are updated. GUI displays the updated position and updated pose of the solid body. 
     When “Release Command” (the third gesture  44 ) is detected at this time, the pose of the solid body is updated, the position of the solid body is returned to IDLE, and the operation mode transits to IDLE. 
     When “Determination Command” (the second gesture  43 ) is detected at SELECT, the application corresponding to an icon having an apparently largest area is executed, the operation mode transits to EXEC. 
     When “Determination Command” (the second gesture  43 ) is detected at EXEC, not only GUI of the demonstration application but GUI of the executed application may be operable. When the application receives “OFF-command” (third gesture  44 ) and position information, the application acquires operation similar to the moving of a normal mouse pointer. When the application receives “ON-command” (third gesture  44 ) and the position information, the application acquires operation similar to normal mouse clicking (like clicking of the right mouse button). 
     When “Determination Command”, “Rotation Information”, and “Position Information” are detected at EXEC, the solid body that has been lastly selected is updated regarding “Rotation Information” and “Position Information”, GUI updates the display of the solid body, the operation mode transits to SELECT. 
     When the “application ending due to ON-Command” is detected at SELECT, the operation mode transits to IDLE. The ON-Command selects and determines an “x” button displayed on the upper portion of the window of the application. The application may be ended by OFF-command (gesture  44 ). 
     Detailed functional requirements in IDLE will be described below. The three-dimensional grid  90  gives notice to the solid body inside the grid  90  when a position in the virtual space  95  is located inside the three-dimensional grid  90  in the virtual space  95 . The solid body receives the notice to raise the brightness of a displayed picture or to brighten the outline of the displayed picture. The three-dimensional grid  90  raises the transparency of solid bodies at the front side of the three-dimensional grid  90  when the pointer corresponding to inputted positional information is located at the rear side of the three-dimensional grid  90 . That is, an icon provided to a solid body located at a rear portion of the three-dimensional grid  90  is easy to be seen. 
     GUI displays a position corresponding to the inputted positional information as a pointer in the virtual space  95 . When an OFF-pose (gesture  44 ) is detected, GUI displays a palm center of the hand and the respective fingers of the hand by different colors. 
     Detailed functional requirements in SELECT will be described. The three-dimensional grid  90  displays positions of the respective fingers in the operation command (gesture  42 ). When a unique surface having a largest apparent area is not identified, applications corresponding to the icons on the largest apparent areas are not executed. 
     As described above, a plurality of solid bodies are preliminarily stored in the three-dimensional grid  90  and displayed in this embodiment. Just a solid body provided with a desired icon is taken out of the three-dimensional grid  90  to thereby perform necessary operations. A plurality of solid bodies is compactly displayed to enable it to execute a target application by a small number of operations. 
     While certain embodiments have been described, these embodiments have been presented by way of example only, and are not intended to limit the scope of the inventions. Indeed, the novel embodiments described herein may be embodied in a variety of other forms; furthermore, various omissions, substitutions and changes in the form of the embodiments described herein may be made without departing from the spirit of the inventions. The accompanying claims and their equivalents are intended to cover such forms or modifications as would fall within the scope and spirit of the inventions.