Patent Publication Number: US-8994883-B2

Title: Display apparatus and display method

Description:
CROSS-REFERENCE TO RELATED APPLICATION 
     The present application is a continuation of U.S. patent application Ser. No. 12/459,449, filed on Jul. 1, 2009, which claims priority from Japanese Patent Application No. JP 2008-173006 filed in the Japanese Patent Office on Jul. 2, 2008, all of which are incorporated herein by reference. 
    
    
     BACKGROUND OF THE INVENTION 
     1. Field of the Invention 
     The present invention relates to a display apparatus and a display method. More particularly, the present invention relates to a display apparatus capable of displaying video providing a sense of perspective in accordance with the line of sight of a user and a display method. 
     2. Description of the Related Art 
     In related art, enhancement processing adapted to video itself to be output to a monitor has been performed. Here, the enhancement processing is processing to improve sharpness of video so that sharper video is presented to the user. However, enhancement processing adapted to video itself to be output to a monitor does not have in most cases three-dimensional information added to the video itself and thus, the video after being processed may be different from what the user likes. 
     Moreover, for example, in Japanese Patent Application Laid-Open No. 2000-221953, a technology to perform image processing in accordance with a detected result after shooting a user by a camera and detecting the line of sight of the user using the shot image is disclosed. 
     [Patent Document 1] Japanese Patent Application Laid-Open No. 2000-221953 
     SUMMARY OF THE INVENTION 
     However, according to the technology disclosed in Japanese Patent Application Laid-Open No. 2000-221953, there is an issue that while image processing can be performed in accordance with the line of sight of the user, it is difficult to display video providing a sense of perspective in accordance with the line of sight of the user. 
     The present invention has been made in view of the above issue, and it is desirable to provide a technology capable of displaying video providing a sense of perspective in accordance with the line of sight of the user. 
     According to an embodiment of the present invention, there is provided a display apparatus, including: a display video information input unit that receives input of display video information to be a source of video displayed in a monitor; a user video information input unit that receives input of user video information, which is acquired by a camera and video information of a user watching video displayed in the monitor; a sight line detection unit that detects a line of sight of the user by analyzing the user video information whose input is received by the user video information input unit; an enhancement processing unit that detects an intersection point of the line of sight of the user detected by the sight line detection unit and a video display surface of the monitor as an attention point and performs enhancement processing for the monitor by setting a higher gain amount in stages from a position of a longer distance from the attention point toward a position of a smaller distance; and a display video output control unit that outputs video via the monitor based on the gain amount set by the enhancement processing unit and the display video information whose input is received by the display video information input unit. 
     According to the above configuration, sharpness of video displayed in a portion of a high degree of attention by the user can be improved. Thus, video providing a sense of perspective in accordance with the line of sight of the user can be displayed. 
     According to the embodiments of the present invention described above, it becomes possible to display video providing a sense of perspective in accordance with the line of sight of the user. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         FIG. 1  is a diagram (Part 1) to explain an overview of a present embodiment; 
         FIG. 2  is a diagram (Part 2) to explain the overview of the present embodiment; 
         FIG. 3  is a function configuration diagram showing a function configuration of a display apparatus according to the present embodiment; 
         FIG. 4  is a diagram schematically showing an example (Part 1) of enhancement processing performed by an enhancement processing unit according to the present embodiment; 
         FIG. 5  is a diagram schematically showing the example (Part 2) of the enhancement processing performed by the enhancement processing unit according to the present embodiment; 
         FIG. 6  is a diagram schematically showing the example (Part 3) of the enhancement processing performed by the enhancement processing unit according to the present embodiment; 
         FIG. 7  is a diagram schematically showing the example (Part 4) of the enhancement processing performed by the enhancement processing unit according to the present embodiment; 
         FIG. 8  is a diagram schematically showing an example of user position detection processing performed by a user position detection unit according to the present embodiment; 
         FIG. 9  is a diagram schematically showing an example of distance calculation processing performed by a distance calculation unit according to the present embodiment; 
         FIG. 10  is a diagram illustrating a case in which a plurality of users is present; 
         FIG. 11  is a diagram illustrating how to apply a gain when the plurality of users is present; 
         FIG. 12  is a flow chart showing a flow of processing performed by the display apparatus according to the present embodiment; 
         FIG. 13  is a diagram illustrating a case in which a plurality of cameras is present; and 
         FIG. 14  is a diagram illustrating a case in which an existing method and a method according to the present embodiment are combined. 
     
    
    
     DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS 
     Hereafter, preferred embodiments of the present invention will be described in detail with reference to the appended drawings. Note that in this specification and the appended drawings, structural elements that have substantially the same functions and structures are denoted with the same reference numerals and a repeated explanation of these structural elements is omitted. 
     &lt;&lt;Overview of the Present Embodiment&gt;&gt; 
     First, an overview of the present embodiment is provided to facilitate an understanding about the present embodiment. 
       FIG. 1  is a diagram (Part 1) to explain an overview of the present embodiment. As shown in  FIG. 1 , a user  30  is a person who views video displayed in a monitor  19  provided with a display apparatus (not shown) such as a TV set. The present embodiment makes video providing a sense of perspective being displayed possible by performing enhancement processing in accordance with the line of sight of the user  30 . Here, the enhancement processing is video processing performed in such a way that the video is presented to the user  30  more sharply or, as described above, processing to improve sharpness of video so that sharper video is presented to the user  30 . The monitor  19  has a camera  11  and the camera  11  is assumed to have a function to shoot the user  30 . It is also assumed that the display apparatus (not shown) having the monitor  19  has internally a function to perform video processing and enhancement processing can be realized, for example, by the function. 
       FIG. 2  is a diagram (Part 2) to explain the overview of the present embodiment.  FIG. 2  is a perspective view of the monitor  19  shown in  FIG. 1  from above. 
     As shown in  FIG. 2 , the point on the monitor  19  on which the user  30  focuses attention is an attention point  41 . The attention point  41  is an intersection point of a line of sight  43  of the user  30  and a video display surface  19 A of the monitor  19 . Moreover, an incident angle  47  of the line of sight  43  to the video display surface  19 A and a distance  40 , which is the shortest distance between the user  30  and the attention point  41 , are specified. In the present embodiment, enhancement processing in accordance with each of the incident angle  47  and the distance  40  will also be described. 
     In the present embodiment, the display apparatus (not shown) detects the direction of the line of sight  43  of the user  30  using the camera  11  (See  FIG. 1 ) and, based on the direction thereof, performs enhancement processing of video to be output to the monitor  19 . In the enhancement processing, a high gain amount is set to pixels on the monitor  19  positioned near the attention point  41 . Accordingly, video that is easy to view for the user  30  and provides a sense of perspective can be provided to the user  30 . Here, the gain amount is a value indicating brightness of each pixel constituting the monitor  19  and refers to the luminance of each of red, green, and blue making up colors. 
     &lt;&lt;Function Configuration of Display Apparatus  10 &gt;&gt; 
       FIG. 3  is a function configuration diagram showing the function configuration of a display apparatus according to the present embodiment. The function configuration of a display apparatus according to the present embodiment will be described with reference to  FIG. 3  ( FIG. 1  and  FIG. 2  are referenced when necessary). 
     As shown in  FIG. 3 , the display apparatus  10 , which is an apparatus (such as a TV set) to display video, includes at least the camera  11 , a tuner  12 , a user video information input unit  110 , a sight line detection unit  120 , a display video information input unit  150 , an enhancement processing unit  160 , a display video output control unit  170 , and the monitor  19 . As shown in  FIG. 3 , the display apparatus  10  may further include a user position detection unit  130  or a distance calculation unit  140 . 
     The camera  11  is used to acquire video information of the user  30  by shooting the user  30 . The camera  11  may be, as shown in  FIG. 3 , contained in the display apparatus  10  or externally connectable to the display apparatus  10 . 
     The user video information input unit  110  is used to receive input of user video information, which is acquired by the camera  11  and video information of the user  30  watching video displayed in the monitor  19 . The user video information input unit  110  is constituted, for example, by a USB (Universal Serial Bus) interface. 
     The sight line detection unit  120  is used to detect a line of sight of the user  30  by analyzing user video information whose input is received by the user video information input unit  110 . The technology to detect the line of sight of the user  30  is not specifically limited. Such a technology is provided, for example, at “Prof. Kenzo Kurihara, [online], [Search on Jun. 11, 2008], Internet &lt;URL: http://joint.idec.or.jp/koryu/020426 — 2.php&gt;”. The sight line detection unit  120  is constituted by a CPU (Central Processing Unit) or the like. In this case, the function of the sight line detection unit  120  is realized by a program stored in a ROM (Read Only Memory) or the like being expanded into a RAM (Random Access Memory) or the like and the program expanded in the RAM being executed by the CPU. The sight line detection unit  120  may also be constituted, for example, by dedicated hardware. 
     The tuner  12  is used to select radio waves of an intended frequency from received radio waves to reproduce video displayed in the monitor  19  from the selected radio waves. Instead of using the tuner  12 , video may be reproduced by using a DVD (digital versatile disk) player or the like. 
     The display video information input unit  150  is used to receive input of display video information to be a source of video displayed in the monitor  19 . The display video information input unit  150  is constituted, for example, by dedicated hardware. 
     The enhancement processing unit  160  is used to detect an intersection point of the line of sight  43  of the user  30  detected by the sight line detection unit  120  and the video display surface  19 A of the monitor  19  as the attention point  41 , which is a point on which the user  30  focuses attention. The enhancement processing unit  160  is used to perform enhancement processing for the monitor  19  by setting a higher gain amount in stages from a position of a longer distance from the detected attention point  41  toward a position of a smaller distance. 
     When the gain amount is set, the enhancement processing unit  160  may set a higher gain amount in stages, among a plurality of regions divided by one or a plurality of concentric circles around the attention point  41 , from a region of a longer distance from the detected attention point  41  toward a region of a smaller distance. 
     Further, when the gain amount is set, the enhancement processing unit  160  may have one or a plurality of concentric circles whose radius is obtained by successively increasing the distance from the attention point  41  by an increment of a predetermined length (See  FIG. 4 ). The predetermined length is assumed to be stored, for example, in the enhancement processing unit  160 . 
     When the gain amount is set, the enhancement processing unit  160  may define the predetermined length as being equal to or less than the distance between adjacent pixels constituting the monitor  19  (See  FIG. 5 ). Accordingly, the plurality of regions divided by one or a plurality of concentric circles around the attention point  41  can be made narrower so that the gain amount changes continuously when viewed from the user  30 . Therefore, video displayed in the monitor  19  can further be made to naturally generate a sense of perspective. 
     Further, when the gain amount is set, the enhancement processing unit  160  may have one or a plurality of concentric circles around the attention point  41  as ellipses having a ratio matching the aspect ratio of the monitor  19  as the major axis/minor axis ratio (ratio of the length of the major axis to that of the minor axis) (See  FIG. 6 ). Accordingly, video displayed in the monitor  19  can be made to generate a sense of perspective fitting to the form of the monitor  19 . The aspect ratio of the monitor  19  may be made, for example, length:breadth=16:9 or the like, but is not specifically limited. 
     The enhancement processing unit  160  is constituted by a CPU or the like. In this case, the function of the enhancement processing unit  160  is realized by a program stored in a ROM or the like being expanded into a RAM or the like and the program expanded in the RAM being executed by the CPU. The enhancement processing unit  160  may also be constituted, for example, by dedicated hardware. 
     The display video output control unit  170  is used to output video via the monitor  19  based on the gain amount set by the enhancement processing unit  160  and display video information whose input is received by the display video information input unit  150 . For example, the display video output control unit  170  is constituted by dedicated hardware. 
     The monitor  19  is used to display video. The monitor  19  may be, as shown in  FIG. 1 , contained in the display apparatus  10  or externally connectable to the display apparatus  10 . 
     The user position detection unit  130  is used to detect the position of the user  30 . A technology to detect the position of the user  30  will be described later with reference to  FIG. 8 , but the present embodiment is not limited to the technology. 
     The user position detection unit  130  is constituted by a CPU or the like. In this case, the function of the user position detection unit  130  is realized by a program stored in a ROM or the like being expanded into a RAM or the like and the program expanded in the RAM being executed by the CPU. The user position detection unit  130  may also be constituted, for example, by dedicated hardware. 
     If the display apparatus  10  further includes the user position detection unit  130 , the enhancement processing unit  160  can set the gain amount by a different technology from the technology described above. The technology will be described below with reference to  FIG. 7 . 
     The distance calculation unit  140  is used to calculate the distance between the monitor  19  and the user  30 . An exemplary technology to calculate the distance between the monitor  19  and the user  30  will be described later with reference to  FIG. 9 , but the present embodiment is not limited to the technology. 
     If the display apparatus  10  further includes the distance calculation unit  140 , the enhancement processing unit  160  can set the gain amount by a different technology from the technology described above. That is, with an increasing distance between the monitor  19  and the user  30  calculated by the distance calculation unit  140 , a higher gain amount can be set in stages. Accordingly, weaker enhancement processing is performed when watched from a relatively short distance and stronger enhancement processing when watched from a relatively long distance so that video of almost the same appearance can be displayed in both cases when viewed from the user  30 . 
     The user video information input unit  110 , the sight line detection unit  120 , the user position detection unit  130 , the distance calculation unit  140 , the display video information input unit  150 , the enhancement processing unit  160 , and the display video output control unit  170  are constituted by LSI (Large Scale Integration) or the like and are central devices of the display apparatus  10 . 
     &lt;&lt;Enhancement Processing Performed by the Enhancement Processing Unit  160 &gt;&gt; 
       FIG. 4  is a diagram schematically showing an example (Part 1) of enhancement processing performed by an enhancement processing unit according to the present embodiment. An example of enhancement processing performed by an enhancement processing unit according to the present embodiment will be described with reference to  FIG. 4 . 
     Reference to  FIG. 4  shows that an aspect when the monitor  19  is viewed from the front is schematically shown above a reference line  50  and that when the monitor  19  is viewed from above is schematically shown below the reference line  50  (This also applies to  FIG. 6  and  FIG. 7 ). 
     The sight line detection unit  120  detects the line of sight  43  of the user  30 . The enhancement processing unit  160  detects an intersection point of the line of sight  43  of the user  30  detected by the sight line detection unit  120  and the video display surface  19 A of the monitor  19  as the attention point  41 , which is a point on which the user  30  focuses attention. The enhancement processing unit  160  also performs enhancement processing for the monitor  19  by setting a higher gain amount in stages from a position of a longer distance from the detected attention point  41  toward a position of a smaller distance. Here, in the example shown in  FIG. 4 , the enhancement processing unit  160  has two concentric circles whose radius is obtained by successively increasing the distance from the attention point  41  by an increment of a predetermined length when the gain amount is set. 
       FIG. 5  is a diagram schematically showing the example (Part 2) of enhancement processing performed by the enhancement processing unit according to the present embodiment. An example of enhancement processing performed by the enhancement processing unit according to the present embodiment will be described with reference to  FIG. 5 . 
     Reference to  FIG. 5  shows that an aspect when the monitor  19  is viewed from the front is shown and graphs for “Application for discontinuous gains” and “Application for continuous gains” are shown thereunder. 
     Two concentric circles around the attention point  41  are shown in the monitor  19  and the video display surface  19 A is divided into three regions by these concentric circles. If a higher gain amount is set in stages from a region of a longer distance from the detected attention point  41  toward a region of a smaller distance, discontinuous gain amounts like the graph “Application for discontinuous gains” shown in  FIG. 5  are set by the enhancement processing unit  160 . Here, the radius of each of the two concentric circles shown in the monitor  19  is a radius that is obtained by successively increasing the distance from the attention point  41  by an increment of a predetermined length. 
     The enhancement processing unit  160  can set the gain amount in such a way that the gain amount changes continuously when viewed from the user  30  by making the predetermined length smaller. For example, the predetermined length may be defined as being equal to or less than the distance between adjacent pixels constituting the monitor  19 . Then, continuous gain amounts like the graph “Application for continuous gains” shown in  FIG. 5  are set by the enhancement processing unit  160 . 
       FIG. 6  is a diagram schematically showing the example (Part 3) of enhancement processing performed by the enhancement processing unit according to the present embodiment. An example of enhancement processing performed by the enhancement processing unit according to the present embodiment will be described with reference to  FIG. 6 . 
     In the example shown in  FIG. 6 , the enhancement processing unit  160  has two concentric circles around the attention point  41  as ellipses having a ratio matching the aspect ratio of the monitor  19  as the major axis/minor axis ratio when the gain amount is set. 
       FIG. 7  is a diagram schematically showing the example (Part 4) of enhancement processing performed by the enhancement processing unit according to the present embodiment. An example of enhancement processing performed by the enhancement processing unit according to the present embodiment will be described with reference to  FIG. 7 . 
     In the example shown in  FIG. 7 , the position of the user  30  is detected by the user position detection unit  130 . In such a case, the enhancement processing unit  160  defines a set of intersection points of a group of lines forming a predetermined angle to the line of sight  43  of the user  30  with the position of the user  30  as a reference point and the video display surface  19 A of the monitor  19  as a boundary when the gain amount is set. In the example shown in  FIG. 7 , each of four auxiliary lines  44  corresponds to a group of lines. 
     By setting one or a plurality of such angles, the enhancement processing unit  160  divides the monitor  19  into a plurality of regions by the boundary. In the example shown in  FIG. 7 , two such angles are set. The enhancement processing unit  160  sets, among the plurality of regions, a higher gain amount in stages from a region of a longer distance from the detected attention point  41  toward a region of a smaller distance. The predetermined angle is assumed to be held, for example, by the enhancement processing unit  160 , which may hold different angles in the longitudinal direction and the lateral direction of the monitor  19 . 
     According to the above assumption, as the user  30  moves away from the monitor  19 , intersection points of the monitor  19  and the auxiliary lines  44  change, which is accompanied by changes of concentric circles. For example, when the strength of enhancement processing in the innermost concentric circle region is the same, the size of region where relatively strong enhancement processing is performed increases if the distance between the user  30  and the monitor  19  is long. As a result, the user  30  can maintain the appearance constant to some extent regardless of the distance between the user  30  and the monitor  19 . 
     When the user  30  watches the monitor  19  obliquely, the shape of the boundary changes to an ellipse having a larger major axis ratio with the increasing incident angle  47 . Therefore, even if the user  30  watches the monitor  19  obliquely, video displayed in the monitor  19  can further be made to naturally generate a sense of perspective. 
     &lt;&lt;User Position Detection Processing Performed by the User Position Detection Unit  130 &gt;&gt; 
       FIG. 8  is a diagram schematically showing an example of user position detection processing performed by a user position detection unit according to the present embodiment. An example of user position detection processing performed by a user position detection unit according to the present embodiment will be described with reference to  FIG. 8  (Other figures are also referenced if necessary). 
       FIG. 8  shows an aspect of the user  30  when viewed from a lens of the camera  11 .  FIG. 8  further has equidistant curves added thereto and if zooming and others are assumed constant, the distance between the monitor  19  and an object such as the user  30  is represented by equidistant curves. Video as shown in  FIG. 8  is shot by the camera  11  and information thereof is acquired by the user position detection unit  130  via the user video information input unit  110  for analysis. For example, by analyzing video information of the user  30  whose input is received by the user video information input unit  110 , the user position detection unit  130  can define the detected position of feet of the user  30  as the position of the user  30 . 
     The enhancement processing unit  160  may set the gain amount by assuming that one angle or each of a plurality of angles formed with the line sight  43  is successively increased by an increment of a predetermined angle. 
     &lt;&lt;Distance Calculation Processing Performed by Distance Calculation Unit  140 &gt;&gt; 
       FIG. 9  is a diagram schematically showing an example of distance calculation processing performed by a distance calculation unit according to the present embodiment. An example of distance calculation processing performed by a distance calculation unit according to the present embodiment will be described with reference to  FIG. 9 . 
     As shown in  FIG. 9 , the relative position of the camera  11  to the monitor  19  is fixed. Thus, the position of the user  30  when the monitor  19  is set as a reference position can be calculated using the relative position and a relative position of the user  30  when the camera  11  is set as a reference position detected by the user position detection unit  130 , so that the distance  40  can be calculated. 
     When the display apparatus  10  further includes the distance calculation unit  140 , the enhancement processing unit  160  can perform enhancement processing appropriate for a distance between the monitor  19  and the user  30  by considering the distance. For example, by setting a higher gain amount in stages with an increasing distance between the monitor  19  and the user  30 , enhancement processing for the monitor  19  can be performed. In this manner, sharp video can be watched even if the user  30  is apart from the monitor  19 . 
     &lt;&lt;When a Plurality of the Users  30  is Present&gt;&gt; 
       FIG. 10  is a diagram illustrating a case in which a plurality of users is present. A case in which the plurality of users is present will be described with reference to  FIG. 10 . 
       FIG. 10  shows a case in which the number of the users  30  present is two as an example of a case in which a plurality of the users  30  is present. In this case, more precise enhancement processing can be performed by performing existing processing when the number of the users  30  is one for two persons. 
     If, for example, the two users  30  turn the lines of sight on the same region, stronger enhancement processing can be performed around the region. If the two users  30  turn the lines of sight  43  on different regions, enhancement processing can be performed on different regions based on information about each of the different regions. The processing can also be applied when the number of the users  30  is three or more. 
     More specifically, the sight line detection unit  120  detects the lines of sight of the users  30  by detecting a plurality of lines of sight as a line of sight of each of the plurality of the users  30 . The enhancement processing unit  160  detects intersection points of the line of sight of each of the plurality of the users  30  detected by the sight line detection unit  120  and the video display surface  19 A of the monitor  19  as each attention point, which is a point on which each of the plurality of the users  30  focuses attention. The enhancement processing unit  160  performs enhancement processing by setting a higher gain amount from a long distance from each attention point toward a shorter position and superimposing the gain amount on each attention point. 
       FIG. 11  is a diagram illustrating how to apply a gain when the plurality of users is present. How to apply a gain when the plurality of users is present will be described with reference to  FIG. 11 . 
     Reference to  FIG. 11  shows that concentric circles around each of the two attention points  41  are overlapped. In such a case, if the enhancement processing unit  160  calculates the gain amount separately for the plurality of the users  30 , each gain amount will be like “Gain amount before superimposition” in  FIG. 11 . 
     Then, the enhancement processing unit  160  adds each gain amount calculated separately. That is, each gain amount is superimposed. The result of superimposition will be like “Gain amount after superimposition” in  FIG. 11 . However, if, as a result of superimposition, the gain amount after superimposition exceeds a predetermined range or becomes larger than a preset threshold value, the gain amount can be adjusted by calculation such as a subtraction of a fixed value from the gain amount after superimposition or a multiplication by a value less than 1. 
     &lt;&lt;Flow of Processing Performed by Display Apparatus  10 &gt;&gt; 
       FIG. 12  is a flow chart showing a flow of processing performed by the display apparatus according to the present embodiment. The flow of processing performed by the display apparatus according to the present embodiment will be described with reference to  FIG. 12  (Other figures are also referenced if necessary). Here, it is assumed that the number n of the user  30  is present. 
     The user video information input unit  110  receives input of user video information, which is acquired by the camera  11  and video information of the user  30  watching video displayed in the monitor  19 . Subsequently, the sight line detection unit  120  analyzes the user video information whose input is received by the user video information input unit  110  to detect the number of the users  30  (step S 101 ). The display apparatus  10  performs processing (step S 102  to step S 106 ) repeating as many times as the number of the users  30  (n persons) detected by the sight line detection unit  120 . 
     In the repetitive processing, the sight line detection unit  120  detects the lines of sight  43  of the users (step S 103 ). Then, the distance calculation unit  140  calculates the distance  40  between the user  30  and the monitor  19  (step S 104 ). The enhancement processing unit  160  calculates the gain amount of each pixel in the monitor  19  from the line of sight  43  and the distance  40  (step S 105 ). 
     When the repetitive processing ends, the enhancement processing unit  160  determines whether the number n of the users  30  is larger than 1 (step S 107 ). If the number n of the users  30  is determined to be larger than 1 (“YES” at step S 107 ), the enhancement processing unit  160  superimposes calculated gain amounts (step S 108 ) before proceeding to step S 109 . If the number n of the users  30  is determined to be equal to or less than 1 (“NO” at step S 107 ), the enhancement processing unit  160  proceeds to step S 109 . 
     The enhancement processing unit  160  sets the gain amount (step S 109 ) and determines whether a predetermined time has passed (step S 110 ). If the predetermined time is determined not to have passed (“NO” at step S 110 ), the enhancement processing unit  160  waits until the predetermined time has passed. If the predetermined time is determined to have passed (“YES” at step S 110 ), the enhancement processing unit  160  returns to step S 101  to repeat the processing. 
     &lt;&lt;When a Plurality of the Cameras  11  is Present&gt;&gt; 
       FIG. 13  is a diagram illustrating a case in which a plurality of cameras is present. A case in which a plurality of cameras is present will be described with reference to  FIG. 13 . 
     As shown in  FIG. 13 , when a plurality of the cameras  11  is present, it is expected that detection will be more precise when the position and line of sight  43  of the user  30  are detected by shooting the user  30  by the plurality of the cameras  11 . 
     &lt;&lt;When Combined With an Existing Method&gt;&gt; 
       FIG. 14  is a diagram illustrating a case in which an existing method and a method according to the present embodiment are combined. A case in which an existing method and a method according to the present embodiment are combined will be described with reference to  FIG. 14 . 
     Here, the existing method is assumed to be a method that sets the gain amount in accordance with video content. As shown in  FIG. 14 , video contains, for example, a building  19 B and enhancement processing according to the existing method has been performed on edges thereof. In such a case, if the gain amount is calculated separately by each method, each gain amount will be like “Gain amount before superimposition” in  FIG. 14 . 
     The enhancement processing unit  160  superimposes the gain amount set by the existing method and that set by a method according to the present embodiment. The result of superimposition is, for example, like “Gain amount after superimposition” in  FIG. 14 . However, if, as a result of superimposition, the gain amount after superimposition exceeds a predetermined range or becomes larger than a preset threshold value, the gain amount can be adjusted by calculation such as a subtraction of a fixed value from the gain amount after superimposition or a multiplication by a value less than 1. 
     Enhancement processing is not limited to the above combination and a plurality of types of enhancement processing can be combined for processing. For example, assume that a method that performs enhancement processing on a focused region by a method according to the present embodiment is a method 1. Further, assume that a method that detects a face portion by adaptive processing of video itself and makes enhancement processing weaker to make video of the portion more desirable video is a method 2. The user  30  can watch more desirable video by performing integrated enhancement processing considering both the method 1 and the method 2 than when enhancement processing is performed separately. 
     By combining with an existing method for performing enhancement processing adapted to video itself, enhancement processing can be performed while retaining advantages of the existing method. 
     According to the present embodiment, enhancement processing suiting the user&#39;s  30  preference can be performed compared with a case in which enhancement processing is performed based on information of video itself by controlling strength of the enhancement processing around the attention point  41  on which the user  30  himself (herself) focuses attention. Further, video providing a sense of perspective can be displayed in accordance with the line of sight of the user. 
     Moreover, appropriate enhancement processing for different spatial relationships, for example, when viewed from the front and obliquely can be performed by detecting the position and the line of sight  43  of the user  30 . 
     It should be understood by those skilled in the art that various modifications, combinations, sub-combinations and alterations may occur depending on design requirements and other factors insofar as they are within the scope of the appended claims or the equivalents thereof.