Abstract:
An auto-stereoscopic image apparatus according to the present disclosure includes a display panel configured to include a plurality of sub pixels and to display images corresponding to a plurality of viewpoints; an optical element configured to be disposed in front of the display panel and to provide parallaxes for the images; a viewpoint detector configured to detect positions of the plurality of viewpoints; and a controller configured to determine viewpoint boundary position of the plurality of sub pixels based on the positions of the plurality of viewpoints and to allocate pixel values of the plurality of sub pixels based on the viewpoint boundary positions.

Description:
BACKGROUND OF THE INVENTION 
       [0001]    1. Field of the Invention 
         [0002]    The present disclosure relates to an auto-stereoscopic image apparatus that changes a display position of auto-stereoscopic image dependent on a position of a viewpoint. 
         [0003]    2. Description of the Related Art 
         [0004]    Patent Literature 1 discloses a parallax image information processing method that variably adjusts an optimum viewable distance and a viewing angle. In this processing method, parallax image information including two or more parallaxes is allocated to each vertical pixel of a liquid crystal panel. When a stereoscopic image is viewed through a parallax barrier disposed in front of the liquid crystal panel, each of parallax image information is allocated to each vertical pixel in a predetermined dividing ratio. 
       CITATION LIST 
     Patent Literature 
       [0005]    PTL 1: Unexamined Japanese Patent Publication No. 2012-255922 
       SUMMARY OF THE INVENTION 
       [0006]    The present disclosure provides an auto-stereoscopic image apparatus that changes a display position of an auto-stereoscopic image dependent on a position of a viewpoint. 
         [0007]    An auto-stereoscopic image apparatus according to the present disclosure includes a display panel configured to include a plurality of sub pixels and to display images corresponding to a plurality of viewpoints; an optical element configured to be disposed in front of the display panel and to provide parallaxes for the images; a viewpoint detector configured to detect positions of the plurality of viewpoints; and a controller that determine viewpoint boundary position of the plurality of sub pixels based on the positions of the plurality of viewpoints and to allocate pixel values of the plurality of sub pixels based on the viewpoint boundary positions. 
         [0008]    The auto-stereoscopic image apparatus according to the present disclosure can display an auto-stereoscopic image corresponding to a change of a position of a viewpoint. 
     
    
     
       BRIEF DESCRIPTION OF DRAWINGS 
         [0009]      FIG. 1  is a schematic diagram showing an auto-stereoscopic image apparatus according to a first exemplary embodiment. 
           [0010]      FIG. 2  is a schematic diagram showing an enlarged portion of an auto-stereoscopic display unit shown in  FIG. 1 . 
           [0011]      FIG. 3  is a schematic diagram showing an auto-stereoscopic image apparatus according to a second exemplary embodiment. 
           [0012]      FIG. 4  is a schematic diagram comparing the auto-stereoscopic display unit according to the first exemplary embodiment with the auto-stereoscopic display unit according to the second exemplary embodiment. 
           [0013]      FIG. 5  is a schematic diagram showing an auto-stereoscopic image apparatus according to a third exemplary embodiment. 
           [0014]      FIG. 6A  is a schematic diagram showing an enlarged portion of the auto-stereoscopic display unit shown in  FIG. 5 . 
           [0015]      FIG. 6B  is an enlarged view showing a part surrounded by dotted lines in  FIG. 6A . 
       
    
    
     DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS 
       [0016]    Hereinafter, exemplary embodiments will be described in detail with reference to the accompanying drawings as appropriate. However, unnecessarily detailed description may occasionally be omitted. For example, detailed description of well-known matters and redundant description of substantially the same configurations may occasionally be omitted. The omission of these items is to avoid the following description from becoming unnecessarily redundant, and to ease understanding of those skilled in the art. 
         [0017]    It should be noted that the following description and the accompanying drawings are provided to allow any person skilled in the art to fully understand the present disclosure, and that it is not intended to limit the subject matter described in the claims by the following description and the accompanying drawings. 
       First Exemplary Embodiment 
       [0018]    Next, with reference to  FIGS. 1 and 2 , an auto-stereoscopic image apparatus in two viewpoints according to the first exemplary embodiment will be described. 
       [1-1. Structure] 
       [0019]      FIG. 1  is a schematic diagram showing an auto-stereoscopic image apparatus in two viewpoints according to the first exemplary embodiment. Auto-stereoscopic image apparatus  10  employs a parallax barrier system that shows different separated images to respective left and right eyes of a user so that the user views a stereoscopic image. Auto-stereoscopic image apparatus  10  includes auto-stereoscopic display unit  100 , viewpoint detector  200 , and controller  300 . 
         [0020]    Auto-stereoscopic display unit  100  includes display panel  110  and parallax barrier  120 . Display panel  110  includes a plurality of sub pixels  111  that display individual colors of R (red), G (green), and B (blue). Pixel values of sub pixels  111  are determined by controller  300 . There are a first viewpoint and a second viewpoint that are positions of the eyes of the user and that are away from display panel  110  by predetermined distances. Sub pixels  111  are arranged periodically, alternately images for the first viewpoint and images for the second viewpoint in a horizontal direction. As long as display panel  110  includes a plurality of sub pixels, display panel  110  may be a liquid crystal panel, a plasma panel, an organic Electro-Luminescence (EL) panel, a Cathode Ray Tube (CRT), or the like. Parallax barrier  120  is a plate-like light shielding member that separately displays images for the first viewpoint and images for the second viewpoint displayed on display panel  110 . Parallax barrier  120  is an optical element including light shielding portions  121  and open portions  122 . The optical element is alternately, periodically disposed light shielding portions  121  and open portions  122 . A ratio of a width of light shielding portion  121  and a width of open portion  122  of parallax barrier  120  may be or may not be 1 to 1. A period for placement of light shielding portions  121  and open portions  122  of parallax barrier  120  may be or may not be an integer multiple of a period of sub pixels  111  of display panel  110 . 
         [0021]    Viewpoint detector  200  detects the first viewpoint and the second viewpoint. To change a stereoscopic view range in a three-dimensional space, viewpoint detector  200  requires position information of the eyes of the user. The position information are a distance from auto-stereoscopic display unit  100  to the eyes of the user, horizontal positions of the eyes of the user to auto-stereoscopic display unit  100 , and vertical positions of the eyes of the user to auto-stereoscopic display unit  100 . 
         [0022]    Controller  300  allocates an image for the first viewpoint and an image for the second viewpoint for each sub pixel  111  in accordance with the positions of the first viewpoint and the second viewpoint detected by viewpoint detector  200 . First, controller  300  determines the periods of the image for the first viewpoint and the image for the second viewpoint periodically, alternately arranged in the horizontal direction based on the distances from auto-stereoscopic display unit  100  to the first viewpoint and the second viewpoint. Next, controller  300  determines to allocate images for the first viewpoint and images for the second viewpoint to the plurality of sub pixels  111  of display panel  110  based on the information detected by viewpoint detector  200  about the horizontal positions of the eyes of the user to auto-stereoscopic display unit  100  and the vertical positions of the eyes of the user to auto-stereoscopic display unit  100 . 
         [0023]      FIG. 2  is a schematic diagram showing an enlarged portion of auto-stereoscopic display unit  100  shown in  FIG. 1 . As shown in  FIG. 2 , when images for the first viewpoint image and images for the second viewpoint are allocated to the plurality of sub pixels  111  of display panel  110 , some of sub pixels  111  may not be allocated only an image for the first viewpoint or only an image for the second viewpoint. In this case, sub pixel  111 A that includes both the image for the first viewpoint and the image for the second viewpoint exists. A pixel value of sub pixel  111 A is a value in which the image for the first viewpoint and the image for the second viewpoint are mixed in a predetermined dividing ratio. Controller  300  determines a position at which the image for the first viewpoint changes to the image for the second viewpoint on display panel  110 , namely a viewpoint boundary position. As shown in  FIG. 2 , in sub pixel  111 A including the viewpoint boundary position, a ratio of a width of the image for the second viewpoint is expressed by “a” (where “a” is a real number in a range of “0&lt;a&lt;1”). If a pixel value of the image for the first viewpoint of sub pixel  111 A is expressed by “X” and a pixel value of the image for the second viewpoint of sub pixel  111 A is expressed by “Y,” then a pixel value of sub pixel  111 A is expressed by “X×(1−a)+Y×a.” 
       [1-2. Effect, etc.] 
       [0024]    As described above, in auto-stereoscopic image apparatus  10  according to the present exemplary embodiment, viewpoint detector  200  detects the positions of the eyes of the user. Controller  300  allocates pixel values to sub pixels based on the detected positions of the eyes of the user. Auto-stereoscopic display unit  100  displays images. 
         [0025]    Thus, auto-stereoscopic display unit  100  can allocate pixel values to sub pixels so that the user can optimally view images. As a result, the user can view auto-stereoscopic images without worrying about a viewing position. 
         [0026]    In addition, since the pixel value of a sub pixel in which an image for the first viewpoint and an image for the second viewpoint are mixed is expressed by “X×(1−a)+Y×a” (where “a” is a real number in a range of “0&lt;a&lt;1”), a sub pixel that is at the boundary of the image for the first viewpoint and the image for the second viewpoint can optimally display the mixed image. As a result, high-quality auto-stereoscopic images can be provided. 
       Second Exemplary Embodiment 
       [0027]    Next, with reference to  FIGS. 3 and 4 , the second exemplary embodiment will be described. 
       [2-1. Structure] 
       [0028]      FIG. 3  is a schematic diagram showing auto-stereoscopic image apparatus  20  in two viewpoints according to the second exemplary embodiment. Auto-stereoscopic image apparatus  20  employs a lenticular system that uses a sheet-type lenticular lens to display stereoscopic images. 
         [0029]    The present exemplary embodiment has a structure in which parallax barrier  120  used in the first exemplary embodiment is substituted with lenticular lens  140 . Auto-stereoscopic image apparatus  20  includes auto-stereoscopic display unit  130 , viewpoint detector  400 , and controller  500 . 
         [0030]    Auto-stereoscopic display unit  130  includes display panel  110  and lenticular lens  140 . Display panel  110  includes a plurality of sub pixels  111  that display individual colors of R (red), G (green), and B (blue). Pixel values of sub pixels  111  are determined by controller  500 . There are a first viewpoint and a second viewpoint that are positions of the eyes of the user and that are away from display panel  110  by predetermined distances. Sub pixels  111  are arranged periodically, alternately images for the irst viewpoint and images for second viewpoint in a horizontal direction. Lenticular lens  140  includes a plurality of hog-backed convex lenses  141 . 
         [0031]      FIG. 4  is a schematic diagram comparing auto-stereoscopic display unit  100  according to the first exemplary embodiment with auto-stereoscopic display unit  130  according to the second exemplary embodiment. 
         [0032]    Lenticular lens  140  of auto-stereoscopic display unit  130  has a structure in which a midpoint of light shielding portion  121  of parallax barrier  120  of auto-stereoscopic display unit  100  corresponds to lens end  142  that is a trough between adjacent convex lenses  141 . In addition, lenticular lens  140  and display panel  110  are disposed so that a distance there between is equal to a distance d between parallax barrier  120  and display panel  110 . Specifically, the distance d is a focal distance f of lenticular lens  140 . 
         [0033]    Viewpoint detector  400  detects the first viewpoint and the second viewpoint. To change a stereoscopic view range in a three-dimensional space, viewpoint detector  400  requires position information of the eyes of the user. The position information are a distance from auto-stereoscopic display unit  130  to the eyes of the user, horizontal positions of the eyes of the user to auto-stereoscopic display unit  100 , and vertical positions of the eyes of the user to auto-stereoscopic display unit  130 . 
         [0034]    Controller  500  allocates an image for the first viewpoint and an image for the second viewpoint for each sub pixel  111  in accordance with the positions of the first viewpoint and the second viewpoint detected by viewpoint detector  400 . First, controller  500  determines the periods of the image for the first viewpoint and image for the second viewpoint periodically, alternately arranged in the horizontal direction based on the distances from auto-stereoscopic display unit  130  to the first viewpoint and the second viewpoint. Next, controller  500  determines to allocate images for the first viewpoint and images for the second viewpoint to the plurality of sub pixels  111  of display panel  110  based on the information detected by viewpoint detector  400  about the horizontal positions of the eyes of the user to auto-stereoscopic display unit  130  and the vertical positions of the eyes of the user to auto-stereoscopic display unit  130 . 
         [0035]    As in the first exemplary embodiment, when images for the first viewpoint and images for the second viewpoint are allocated to the plurality of sub pixels  111  of display panel  110 , some of sub pixels  111  may not be allocated only an image for the first viewpoint or only an image for the second viewpoint. In this case, sub pixel  111 A that includes both the image for the first viewpoint and the image for the second viewpoint exists. A pixel value of sub pixel  111 A is a value in which the image for the first viewpoint and the image for the second viewpoint are mixed in a predetermined dividing ratio. Controller  500  determines a position at which the image for the first viewpoint changes to the image for the second viewpoint on display panel  110 , namely a viewpoint boundary position. In sub pixel  111 A including the viewpoint boundary position, a ratio of a width of the image the second viewpoint image is expressed by “a” (where “a” is a real number in a range of “0&lt;a&lt;1”). If a pixel value of the image for the first viewpoint of sub pixel  111 A is expressed by “X” and a pixel value of the image for the second viewpoint image of sub pixel  111 A is expressed by “Y,” then a pixel value of sub pixel  111 A is represented by “X×(1−a)+Y×a.” 
         [0036]    The present exemplary embodiment describes the structure using the lenticular lens. Alternatively, as long as light is deflected from display panel  110 , any structure that does not use the lenticular lens may be used. For example, a structure using a liquid crystal lens may be used. 
       [2-3. Effect, etc.] 
       [0037]    As described above, in auto-stereoscopic image apparatus  20  according to the present exemplary embodiment, viewpoint detector  400  detects the positions of the eyes of the user. Controller  500  allocates pixel values to sub pixels based on the detected positions of the eyes of the user. Auto-stereoscopic display unit  130  displays images. 
         [0038]    Thus, auto-stereoscopic display unit  130  can allocate pixel values to sub pixels so that the user can optimally view images. As a result, the user can view auto-stereoscopic images without worrying about a viewing position. 
         [0039]    In addition, since the pixel value of a sub pixel in which an image for the first viewpoint and an image for the second viewpoint are mixed is expressed by “X×(1−a)+Y×a” (where “a” is a real number in a range of “0&lt;a&lt;1”), a sub pixel that is at the boundary of the image for the first viewpoint and the image for the second viewpoint can optimally display the mixed image. As a result, high-quality auto-stereoscopic images can be provided. 
       Third Exemplary Embodiment 
       [0040]    Next, with reference to  FIG. 5 ,  FIG. 6A , and  FIG. 6B , the third exemplary embodiment will be described. 
       [3-1. Structure] 
       [0041]      FIG. 5  is an schematic diagram showing auto-stereoscopic image apparatus  30  in four viewpoints according to the third exemplary embodiment. The present exemplary embodiment has a structure in which parallax barrier  120  used in the first exemplary embodiment is substituted with parallax barrier  160 . 
         [0042]    Auto-stereoscopic image apparatus  30  includes auto-stereoscopic display unit  150 , viewpoint detector  600 , and controller  700 . 
         [0043]    Auto-stereoscopic display unit  150  includes display panel  110  and parallax barrier  160 . Display panel  110  includes a plurality of sub pixels  111  that display individual colors of R (red), G (green), and B (blue). Pixel values of sub pixels  111  are determined by controller  700 . There are a first viewpoint, a second viewpoint, a third viewpoint, and a fourth viewpoint that are positions of the eyes of users and that are away from display panel  110  by predetermined distances. Sub pixels  111  are arranged periodically, alternately images for the first viewpoint image, images for the second viewpoint, images for the third viewpoint, and images for the fourth viewpoint in a horizontal direction. As long as display panel  110  includes a plurality of sub pixels, display panel  110  may be a liquid crystal panel, a plasma panel, an organic EL panel, a CRT, or the like. Parallax barrier  160  is a plate-like light shielding member that separately displays images for the first viewpoint, images for the second viewpoint, images for the third viewpoints and images for the fourth viewpoints displayed on display panel  110 . Parallax barrier  160  is an optical element including light shielding portions  161  and open portions  162 . The optical element is alternately, periodically disposed light shielding portions  161  and open portions  162 . Opening portions  162  of parallax barrier  160  according to the present exemplary embodiment are narrower than those of parallax barrier  120  according to the first exemplary embodiment. Specifically, in parallax barrier  160 , a ratio of light shielding portion  161  and open portion  162  is less than 3:1. 
         [0044]    Viewpoint detector  600  detects the first viewpoint, the second viewpoint, the third viewpoint, and the fourth viewpoint. To change a stereoscopic view range in a three-dimensional space, viewpoint detector  600  requires position information of the eyes of the users. The position information are a distance from auto-stereoscopic display unit  150  to the eyes of the users, horizontal positions of the eyes of the users to auto-stereoscopic display unit  150 , and vertical positions of the eyes of the users to auto-stereoscopic display unit  150 . 
         [0045]    Controller  700  allocates an image for the first viewpoint, an image for the second viewpoint, an image for the third viewpoint, and an image for the fourth viewpoint for each sub pixel  111  in accordance with the positions of the first viewpoint, the second viewpoint, the third viewpoint, and the fourth viewpoint detected by viewpoint detector  600 . First, controller  700  determines the periods of the image for the first viewpoint, the image for the second viewpoint, the image for the third viewpoint, and the image for the fourth viewpoint periodically, alternately arranged in the horizontal direction based on the distances from auto-stereoscopic display unit  150  to the first viewpoint, the second viewpoint, the third viewpoint, and the fourth viewpoint. Next, controller  700  determines to allocate images for the first viewpoint, images for the second viewpoint, images for the third viewpoint, and images for the fourth viewpoint to the plurality of sub pixels  111  of display panel  110  based on the information detected by viewpoint detector  600  about the horizontal positions of the eyes of the users to auto-stereoscopic display unit  150  and the vertical positions of the eyes of the users to auto-stereoscopic display unit  150 . 
         [0046]      FIG. 6A  is schematic diagram showing an enlarged portion of auto-stereoscopic display unit  150  shown in  FIG. 5 .  FIG. 6B  is a enlarged view showing a part surrounded by dotted lines in  FIG. 6A . 
         [0047]    As in the image for the first viewpoint and an image for the second viewpoint, a pixel value of sub pixel  111  is a value in which images for the adjacent viewpoints are mixed in a predetermined dividing ratio. However, as shown in  FIG. 6A  and  FIG. 6B , at sub pixel  111 B in which the image for the first viewpoint and the image for the second viewpoint are mixed, the boundary of the first viewpoint and the boundary of the second viewpoint are not in contact with each other. In this case, controller  700  determines that a viewpoint boundary position is equidistant from the boundary of the first viewpoint and the boundary of the second viewpoint. As shown in  FIG. 6A  and  FIG. 6B , in sub pixel  111 B including the viewpoint boundary position, the ratio of the width of the image for the second viewpoint is expressed by “b” (where “b” is a real number in a range of “0&lt;b&lt;1”). If a pixel value of the image for the first viewpoint of sub pixel  111 B is expressed by “X” and a pixel value of the image for the second viewpoint of sub pixel  111 B is expressed by “Y,” then the pixel value of sub pixel  111 B is expressed by “X×(1−b)+Y×b.” 
         [0048]    In  FIG. 6A  and  FIG. 6B , a pixel value of a sub pixel at the boundary of the first viewpoint and the second viewpoint is obtained. However, the present disclosure is not limited to the above example, likewise, a pixel value of a sub pixel at a boundary of the second viewpoint and the third viewpoint and a pixel value of a sub pixel at a boundary of the third viewpoint and the fourth viewpoint can be obtained. 
       [3-3. Effect, etc.] 
       [0049]    As described above, in auto-stereoscopic image apparatus  30  according to the present exemplary embodiment, viewpoint detector  600  detects the positions of the eyes of the users. Controller  700  allocates pixel values to sub pixels based on the detected positions of the eyes of the users. Auto-stereoscopic display unit  150  displays images. 
         [0050]    Thus, auto-stereoscopic display unit  150  can allocate pixel values to sub pixels so that the user can optimally view images. As a result, the user can view auto-stereoscopic images without worrying about a viewing position. 
         [0051]    In addition, since the pixel value of a sub pixel in which an image for the first viewpoint and an image for the second viewpoint are mixed is expressed by “X×(1−b)+Y×b” (where “b” is a real number in a range of “0&lt;b&lt;1”), a sub pixel that is at the boundary of the image for the first viewpoint and the image for the second viewpoint can optimally display the mixed image. As a result, high-quality auto-stereoscopic images can be provided.