CROSS-REFERENCE TO RELATED APPLICATION 
       [0001]    Relevant subject matter is disclosed in the co-pending U.S. patent application (Attorney Docket No. US32448) having the same title, which is assigned to the same assignee as named herein. 
     
    
     BACKGROUND 
       [0002]    1. Technical Field 
         [0003]    The present disclosure relates to a media display system and an adjustment method for the media display system. 
         [0004]    2. Description of Related Art 
         [0005]    Outdoor media, such as electronic billboards, provide advertising and information to the public. Most of these electronic billboards are mounted at a fixed height. Viewing of the display may be uncomfortable or difficult for those viewers that must turn or angled their heads to properly read or view what is on the electronic billboard. 
     
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         [0006]    Many aspects of the embodiments can be better understood with reference to the following drawings. The components in the drawings are not necessarily drawn to scale, the emphasis instead being placed upon clearly illustrating the principles of the present embodiments. Moreover, in the drawings, like reference numerals designate corresponding parts throughout the several views. 
           [0007]      FIG. 1  is an isometric view of an exemplary embodiment of a media display system with a driving apparatus. 
           [0008]      FIG. 2  is similar to  FIG. 1 , but viewed from another perspective. 
           [0009]      FIG. 3  is an explored, isometric view of the driving apparatus of  FIG. 1 . 
           [0010]      FIG. 4  is a block diagram of the media display system of  FIG. 1  with a storage unit. 
           [0011]      FIG. 5  is a block diagram of the storage unit of  FIG. 4 . 
           [0012]      FIGS. 6 and 7  are schematic views showing adjusting of the media display system of  FIG. 1 . 
           [0013]      FIG. 8  is a flowchart of an exemplary embodiment of an adjustment method for a media display system. 
       
    
    
     DETAILED DESCRIPTION 
       [0014]    The disclosure, including the accompanying drawings, is illustrated by way of example and not by way of limitation. It should be noted that references to “an” or “one” embodiment in this disclosure are not necessarily to the same embodiment, and such references mean at least one. 
         [0015]    Referring to  FIGS. 1 to 4 , an exemplary embodiment of a media display system  1  includes an electronic billboard  10 , two time-of-flight (TOF) cameras  12 , a storage unit  15 , a processing unit  17 , a pair of driving apparatuses  16 , and a stand  18 . The media display system  1  can adjust a height of the electronic billboard  10 . Referring to  FIG. 6 , in the embodiment, it is assumed that when a viewer&#39;s eyeline is aligned with a midline of the electronic billboard  10 , viewability is optimized. In other embodiments, the relationship between the electronic billboard  10  and the viewer can be preset. 
         [0016]    The TOF cameras  12  are mounted on a left side and a right side of the horizontally extended midline (the midline) of the electronic billboard  10 , respectively, to capture images of a scene in front of the electronic billboard  10 , and create data about distances between a plurality of points in the scene and the TOF cameras  12 . The processing unit  17  and the storage unit  15  process the images and the data about distances obtained by the TOF cameras  12  to obtain a three dimension (3D) model of the scene in front of the electronic billboard  10 , for determining a reference eyeline E 1  in the 3D model and a midline M 1  of the 3D model. The processing unit  17  and the storage unit  15  further control the driving apparatus  16  to adjust the height of the electronic billboard  10  to synchronize the reference eyeline E 1  and the midline M 1  of the 3D model. In other embodiments, there may be only one TOF camera  12  mounted on the left side or the right side of the midline of the electronic billboard  10 . 
         [0017]    Each TOF camera  12  is a camera system that creates data about distances between a plurality of points in front of the electronic billboard  10  and the TOF camera  12 . When the TOF camera  12  shoots the scene in front of the electronic billboard  10 , the TOF camera  12  sends radio frequency (RF) signals. The RF signals would return to the TOF camera  12  when the RF signals meet an object, such as a tree in the scene. As a result, the data about distances can be obtained according to time differences between sending and receiving the RF signals of the TOF camera  12 . 
         [0018]    In the embodiment, the stand  18  has a Y-shaped configuration and includes a pair of vertical arms  181 . Each of the arms  181  defines a receiving space, and a vertical slot defined in a first sidewall of the arms  181  communicates with the receiving space. Each driving apparatus  16  includes a motor  160  attached to a rear of the billboard  10 , a gear  161  attached to a rotor of the motor  160 , and a track  162  formed on an inside of a second sidewall of the arm  181  perpendicular to the first sidewall. The gear  161  is received in the receiving space of the stand  18  to engage the track  162  and the rotor of the motor  160  extends through the slot of the stand  18 . In addition, a motion sensor (such as, a G sensor)  13  is mounted to the electronic billboard  10  to determine whether the electronic billboard  10  moves when the driving apparatus  16  operates. 
         [0019]    Referring to  FIG. 5 , the storage unit  15  includes a three dimension (3D) building module  151 , a 3D model storing module  155 , a facial detection module  150 , an eye detection module  152 , a midline determination module  153 , a comparison module  156 , and a control module  158 . The 3D building module  151 , the facial detection module  150 , the eye detection module  152 , the midline determination module  153 , the comparison module  156  and the control module  158  may include one or more computerized instructions executed by the processing unit  17 . 
         [0020]    The 3D model building module  151  builds a 3D model of the scene in front of the electronic billboard  10  according to the image captured by the TOF camera  12  and the data about distances between the plurality of points in the scene and the TOF camera  12 . In the embodiment, according to the data about distances between the plurality of points in the scene in front of the electronic billboard  10  and the TOF camera  12 , the plurality of points in the scene has coordinates relative to the TOF camera  12 . The 3D model building module  151  can obtain a 3D mathematical model according to the coordinates of the plurality of points and the image. The 3D mathematical model can be regarded as the 3D model of the scene in front of the electronic billboard  10 . 
         [0021]    The 3D model storing module  155  stores a plurality of different 3D models of human faces. The different 3D models of human faces can be obtained by the TOF camera  12  in advance. 
         [0022]    The facial detection module  150  checks the 3D model of the scene in front of the electronic billboard  10  to find a face region in the 3D model of the scene. In the embodiment, the facial detection module  150  compares the different 3D models of human faces stored in the 3D model storing module  155  with the obtained 3D model of the scene in front of the electronic billboard  10  to find the face region in the 3D model of the scene. 
         [0023]    The eye detection module  152  detects the reference eyeline E 1  of the eye in the face region in the 3D model. The eye detection module  152  uses well known recognition technology to find an eye region in the face region. In other embodiment, a top one-third of the face region can be regarded as the reference eyeline E 1 . 
         [0024]    The midline determination module  155  obtains the midline M 1  of the 3D model of the scene on a Y-axis of a coordinate system. The comparison module  156  compares the midline M 1  and the reference eyeline E 1  of the face region in the 3D model of the scene, and outputs a corresponding comparison signal to the control module  158 . The control module  158  directs the driving apparatus  16  to adjust the height of the electronic billboard  10 . 
         [0025]    Referring to  FIG. 6 , the TOF camera  12  captures an image of the scene in front of the electronic billboard  10  and obtains distance data. The 3D model building module  151  builds a 3D model  30  of the scene in front of the electronic billboard  10  according to the image captured by the TOF camera  12  and the distance data. In the embodiment, in the 3D model  30 , other portions, such as the shoulder and neck, are cropped. 
         [0026]    The facial detection module  150  checks the face region  32  in the 3D model  30 . The eye detection module  152  calculates the reference eyeline E 1  in the face region  32 . The midline determination module  155  obtains the midline M 1  of the 3D model  30  on the Y-axis of the coordinate system. The comparison module  156  compares the midline M 1  of the 3D model  30  on the Y-axis of the coordinate system with the reference eyeline E 1  in the face region  32  to determine that the reference eyeline E 1  of the face region  32  is misaligned with the midline M 1  of the 3D model  30 , and outputs a corresponding comparison signal to the control module  158 . 
         [0027]    The control module  158  directs the driving apparatus  16  to move the electronic billboard  10  up a distance, such as two centimeters. Conversely, if the reference eyeline E 1  of the face region  32  in the 3D model  30  is lower than the midline M 1  of the 3D model  30 , the control module  158  directs the driving apparatus  16  to move the electronic billboard  10  down a distance, such as one centimeter. Repeating these actions, referring to  FIG. 7 , to overlap the midline M 1  of the 3D model  30  on the Y-axis of the coordinate system with the reference eyeline E 1 . Then, the control module  158  stops the driving apparatus  16   
         [0028]    When the TOF camera  12  is mounted on the midline of the electronic billboard  10 , the midline of the electronic board  10  is in alignment with the midline M 1  of the 3D model  30  on the Y-axis of the coordinate system. Referring to  FIG. 7 , when the reference eyeline E 1  of the face region  32  is in alignment with the midline M 1  of the 3D model  30  on the Y-axis of the coordinate system, the viewer can comfortably view the electronic billboard  10 . 
         [0029]    In the embodiment described above, there is only one viewer. In other embodiments, if there is more than one viewer, the facial detection module  150  checks the 3D model to locate a plurality of face regions in the 3D model. The eye detection module  152  checks the face regions to locate a reference eyeline in each face region, and obtains an average location of the plurality of eye regions. The comparison module  156  compares the average reference eyeline of the eye regions with the midline M 1  of the 3D model  30  on the Y-axis of the coordinate system. 
         [0030]      FIG. 8  shows an adjustment method for an electronic billboard  10  as follows. 
         [0031]    In step S 81 , the TOF camera  12  captures an image of a scene in front of the electronic billboard  10 . The TOF camera  12  further gathers data about distances between a plurality of points in the scene and the TOF camera  12 . 
         [0032]    In step S 82 , the 3D model building module  155  builds a 3D model  30  of the scene in front of the electronic billboard  10  according to the image captured by the TOF camera  12  and the data about distances between the plurality of points in the scene and the TOF camera  12 . 
         [0033]    In step S 83 , the facial detection module  150  checks the 3D model  30  to find a face region  32  in the 3D model  30 . 
         [0034]    In step S 84 , the eye detection module  152  detects a reference eyeline in the face region  32 . 
         [0035]    In step S 85 , the midline determination module  153  obtains the midline M 1  of the 3D model  30  on the Y-axis of the coordinate system. 
         [0036]    In step S 86 , the comparison module  156  compares the reference eyeline E 1  with the midline M 1  of the 3D model  30  to determine whether the reference eyeline E 1  and the midline M 1  overlap. Once the reference eyeline E 1  and the midline M 1  overlap, the viewer can comfortably view the contents on the electronic billboard  10 . If the reference eyeline E 1  and the midline M 1  are not overlapped, step S 87  is implemented. 
         [0037]    In step S 87 , the comparison module  156  outputs a comparison signal according to the comparison of the midline M 1  and the reference eyeline E 1  of the face region in the 3D model of the scene. 
         [0038]    In step S 88 , the control module  158  directs the driving apparatus  16  to move according to the comparison signal, and step S 81  is repeated. 
         [0039]    The foregoing description of the embodiments of the disclosure has been presented only for the purposes of illustration and description and is not intended to be exhaustive or to limit the disclosure to the precise forms disclosed. Many modifications and variations are possible in light of the above everything. The embodiments were chosen and described in order to explain the principles of the disclosure and their practical application so as to enable others of ordinary skill in the art to utilize the disclosure and various embodiments and with various modifications as are suited to the particular use contemplated. Alternative embodiments will become apparent to those of ordinary skills in the art to which the present disclosure pertains without departing from its spirit and scope. Accordingly, the scope of the present disclosure is defined by the appended claims rather than the foregoing description and the exemplary embodiments described therein.
An adjustment method for a media display system includes a time-of-flight (TOF) camera capturing an image of a scene in front of an electronic billboard and obtaining data about distances between a number of points in the scene and the TOF camera. Building a three dimension (3D) model of the scene. Checking the 3D model to detect a face region in the 3D model. Detecting a reference eyeline in the 3D model. Obtaining a midline of the 3D model. Comparing the reference eyeline with the midline to determine whether the two lines overlap and outputting a comparison signal correspondingly, and driving a driving apparatus according to the comparison signal to adjust height of the electronic billboard.