JP2013016976A - Image display device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide an image display device capable of appropriately determining a screen direction.SOLUTION: An image display device includes: a display screen 13 for displaying an image; imaging means 11 for imaging the anterior part of the display screen 13 and acquiring an image; person detection means 22 for detecting a person from the acquired image; viewing possibility analysis means 23 for calculating the motion amount of the detected person, calculating an analysis value expressing a possibility that the person is viewing an image on the basis of the direction of the face of the person, and weighting the analysis value in accordance with the motion amount; viewer determination means 24 for determining whether the detected person is the viewer of the display screen 13 or not based on the weighted analysis value; direction determination means 25 for determining the screen direction of the display screen 13 on the basis of the position of the person determined to be the viewer by the viewer determination means 24; and drive means 26 for driving by rotation the display screen 13 in the screen direction determined by the direction determination means 25.

Description

  The present invention relates to a video display device.

  As a conventional television receiver, an image on the front side of a display screen that displays video is acquired, a face image included in the acquired image is identified, and the screen is oriented so that the screen direction is at the position of the identified face image Some rotate the screen (for example, see Patent Document 1).

JP 2009-296521 A

  However, when a face image in the acquired image is identified, a poster on which a person's face is printed may be identified as an actual person's face. In such a case, the position of the viewer, who is the person watching the screen, is not properly determined, and the screen direction is determined in a direction unrelated to the viewer, so that the viewer can view the screen at the optimum angle. There was a problem that it became impossible to see.

  The present invention has been made to solve the above-described problems, and an object thereof is to obtain a video display device capable of appropriately determining the screen direction.

  The video display device according to the present invention includes a display screen for displaying video, an imaging means for capturing an image by capturing the front of the display screen, a person detecting means for detecting a person from the acquired image, and a detected person A viewability analysis means for calculating an amount of motion, calculating an analysis value representing the possibility that the person is viewing the video based on the orientation of the face of the person, and weighting the analysis value according to the amount of motion; Based on the weighted analysis value, based on the viewer determination means for determining whether or not the detected person is the viewer of the display screen, and the position of the person determined to be the viewer by the viewer determination means Direction determining means for determining the screen direction of the display screen, and drive means for rotationally driving the display screen in the screen direction determined by the direction determining means.

  According to the present invention, an analysis value indicating the possibility that a person is watching a video is weighted according to the amount of motion, and it is determined whether or not the detected person is a viewer based on the weighted analysis value. Therefore, the screen direction can be determined appropriately.

1 is a block diagram showing a configuration of a video display device according to Embodiment 1. FIG. 3 is a block diagram illustrating a configuration of an information processing device in the video display device according to Embodiment 1. FIG. 6 is a top view showing a method for determining an angle θ in the video display apparatus according to Embodiment 1. FIG. 6 is a diagram illustrating an example of person information detected by a person detection unit in the video display apparatus according to Embodiment 1. FIG. 6 is a diagram illustrating a specific example of determining a viewer from person information in the video display apparatus according to Embodiment 1. FIG. 6 is a diagram illustrating a relationship between a screen direction and a divided region in the video display device according to Embodiment 1. FIG. 6 is a flowchart showing a control procedure of the information processing apparatus in the video display apparatus according to Embodiment 1. FIG. FIG. 10 is a top view showing a method for determining an angle θ in a first modification of the video display apparatus according to Embodiment 1. FIG. 10 is a top view showing a method for determining an angle θ in a second modification of the video display apparatus according to Embodiment 1. FIG. 10 is a diagram illustrating a modified example of a divided region in the video display device according to the first embodiment. 6 is a block diagram illustrating a configuration of an information processing device in a video display device according to Embodiment 2. FIG. FIG. 10 is a flowchart showing a control procedure of the information processing apparatus in the video display apparatus according to Embodiment 2.

Embodiment 1 FIG.
First, the configuration of the video display device according to the first embodiment will be described. FIG. 1 is a block diagram showing the configuration of the video display apparatus according to the first embodiment.

  In FIG. 1, the video display device 100 includes an imaging device 11, a rotary stand 12, a display screen 13, and an information processing device 14. The video display device 100 determines the screen direction in which the display screen 13 is directed according to the position of the viewer who is viewing the display screen 13, and automatically rotates the display screen 13 in the direction of the screen by the rotary stand 12. Is.

  The display screen 13 is a screen for displaying an image, and is a liquid crystal display screen, for example.

  The rotary stand 12 is a stand that holds the display screen 13 and includes a drive unit such as a motor or a gear, and can rotate the display screen 13 around a substantially vertical axis within a certain angle range. The information processing device 14 controls the start or stop of rotation and the rotation direction. In addition, the rotary stand 12 may be provided with a means for acquiring a direction in which the display screen 13 is facing, such as a rotary encoder.

  The imaging device 11 captures the front of the display screen 13 to acquire an image, and outputs the acquired image (specifically, digital image data) to the information processing device 14. Acquisition of an image by the imaging device 11 and output of the captured image to the information processing device 14 are repeatedly performed, for example, 30 times per second.

  The imaging device 11 includes a CCD (Charge Coupled Device) element, a lens, and the like, and acquires a grayscale image having a resolution of 640 × 480 pixels. The imaging device 11 may use an imaging element other than a CCD element, such as a CMOS (Complementary Metal Oxide Semiconductor) element. Further, the imaging device 11 may acquire a color image instead of a grayscale image. Further, the resolution of the image is not limited to 640 × 480 pixels, and may be higher or lower as long as a person can be detected. Note that, depending on the angle of view of the imaging device 11, generally, the higher the resolution, the farther a person can be detected.

  The information processing apparatus 14 calculates the position of the viewer who is viewing the video displayed on the display screen 13 based on the image acquired by the imaging apparatus 11, and makes the display screen 13 easy to see from the position of the viewer. The rotary stand 12 is controlled to rotate the display screen 13.

  Next, the configuration of the information processing apparatus 14 will be described. FIG. 2 is a diagram illustrating a configuration of the information processing apparatus according to the first embodiment.

  In FIG. 2, the information processing apparatus 14 includes an imaging processing unit 21, a person detection unit 22, a viewability analysis unit 23, a viewer determination unit 24, a direction determination unit 25, and a drive control unit 26.

  The imaging processing unit 21 acquires an image captured by the imaging device 11. Then, the imaging processing unit 21 outputs the acquired image (hereinafter referred to as “captured image”) to the person detection unit 22.

  The person detection unit 22 detects a person from the captured image acquired by the imaging processing unit 21, and detects three pieces of information (referred to as person information) including the position of the person, the size of the face, and the orientation of the face in the captured image. .

  Specifically, the person detection unit 22 detects the center coordinate of the face of the person in the coordinate system of the captured image as information on the position of the person, and the information in the coordinate system of the captured image as information on the size of the face. The width of the human face (specifically, the horizontal width of the face) is detected.

  FIG. 3 is a top view showing a method of determining the angle θ in the video display apparatus according to Embodiment 1. As shown in FIG. 3, the person detection unit 22 uses the angle θ (0 ° ≦ θ ≦ 90) between the perpendicular line 31 of the display screen 13 and the line 32 indicating the face direction of the person as face direction information. °) is detected. The angle θ is 0 ° when the person is facing the front with respect to the display screen 13, and is 90 ° when the person is facing sideways with respect to the display screen 13.

  Note that a method of detecting a person in the person detection unit 22 is not particularly limited. For example, a method called a viola-Jones method disclosed in US Patent Application Publication No. 2002/0102024 can be used. In summary, the Viola-Jones method sets a small area in an image while changing the position and size of the small area in the image, extracts a feature amount from the small area, and uses the discriminator to extract the small area. It is determined whether or not the area is a face. After applying the Viola-Jones method to the captured image, the person detection unit 22 determines the center position of the face and the size of the face represented by the coordinate axes of the captured image from the position and size of the small area determined to be a face. You can ask for it. In addition, when applying the Viola-Jones method to the captured image, the person detection unit 22 does not only determine whether or not the face is a face, for example, whether or not the face is facing the front, By determining whether or not the face is about 30 degrees to the right of the front about the vertical axis and whether the face is about 30 degrees to the left of the front about the vertical axis, The direction of the face can be obtained.

  FIG. 4 is a diagram illustrating an example of person information detected by the person detection unit in the video display apparatus according to Embodiment 1. In FIG. 4, “No.” is a number assigned to the detected person, “x coordinate” and “y coordinate” are the center coordinates of the face of each person, and “face size” is the face width of each person. “Face orientation (θ)” is an angle θ formed by the perpendicular line 31 of the display screen 13 and the line 32 indicating the direction of the person. In FIG. 1-No. 3 shows a case where three persons are detected.

Information on the position of the person and information on the size of the face include the length of the face (specifically, the length of the face in the vertical direction), the shoulder width, the distance between both eyes, the position of each eye, and the vertex of the head. Other information such as the coordinates may be detected. Further, when a plurality of persons are detected from the captured image, the position, face size, and face direction of the person in the captured image are detected for each of the detected persons.

  The person detection unit 22 outputs the center coordinates of the person's face and the angle θ described above to the viewability analysis unit 23.

  The viewing possibility analysis unit 23 analyzes the possibility that each person detected by the person detection unit 22 is watching the video.

  Specifically, the viewability analyzing unit 23 calculates a value of 90−θ using the angle θ (the value of 90−θ is referred to as a viewability analysis value). The viewability analysis value becomes maximum (90−θ = 90) when the person having a larger value is more likely to view the image and the detected person faces the front with respect to the display screen 13. The minimum value (90−θ = 0) is obtained when the display screen 13 is directed to the side.

  The viewability analysis unit 23 calculates a motion vector at the position of the person detected from the captured image of the current frame using the captured image of the current frame and the captured image of the previous frame, The amount of motion is calculated as an absolute value. Then, the viewability analysis unit 23 weights the viewability analysis value according to whether or not the calculated amount of motion is larger than a threshold value. For this weighting, for example, the viewability analysis value of the person whose calculated motion amount is smaller than the threshold value is multiplied by 0.1, and the viewability analysis value of the person whose motion amount is larger than the threshold value is not changed. To do.

Note that a block matching method, a gradient method, or the like can be used as the motion vector calculation method. The amount of motion is not limited to a specific time, but may be a motion amount calculated over a predetermined time, for example, an average value thereof.

  In addition, the viewability analysis unit 23 divides the captured image into a plurality of divided regions, and associates the detected person with which divided region, using the above-described center coordinates of the person's face. Then, the viewability analysis unit 23 outputs the position of the divided area including the detected person and the weighted viewability analysis value in the divided area to the viewer determination unit 24.

  The viewer determination unit 24 determines whether or not the person detected by the person detection unit 22 is a viewer based on the weighted viewability analysis value. Whether or not a person is a viewer is determined as a viewer if the weighted viewability analysis value is larger than the threshold, and not as a viewer if the weight is smaller. Then, the viewer determination unit 24 outputs the position of the divided area where the viewer exists to the direction determination unit 25.

  Here, a specific example of determining a viewer from person information will be described. FIG. 5 is a diagram showing a specific example of determining a viewer from person information in the video display apparatus according to Embodiment 1, wherein (a) is a diagram showing a person in a captured image, and (b) is viewable. The figure which represented the analysis result of the sex analysis part for every division area, (c) is the figure which represented the determination result of the viewer determination part for every division area.

  In FIG. 5A, the captured image includes a person 33a and a person 33b. The person 33 a is a viewer viewing the display screen 13 from the front, and the person 33 b is a poster printed so that the face of the person is in front of the display screen 13.

  As shown in FIG. 5B, the viewability analyzing unit 23 first associates the divided regions to which the persons 33a and 33b are included. The person 33a is included in the divided area 35a, and the person 33b is included in the divided area 35b. Next, the viewability analysis unit 23 calculates a viewability analysis value. Since both the persons 33a and 33b are θ = 0 °, the viewability analysis value is 90. Next, the viewability analyzing unit 23 calculates the amount of movement of the persons 33a and 33b, respectively. Here, the motion amount of the person 33a is larger than the threshold value, and the motion amount of the person 33b is smaller than the threshold value. Then, the viewability analysis unit 23 weights the viewability analysis value of the person 37b whose motion amount is smaller than the threshold value by 0.1 times. As a result, the viewability analysis value is analyzed as 90 for the person 33a and 9 for the person 33b. Then, the viewability analysis unit 23 outputs the positions of the divided areas 35a and 35b where the person is detected and the weighted viewability analysis values in the divided areas 35a and 35b to the viewer determination unit 24.

  As shown in FIG. 5C, the viewer determination unit 24 determines that the viewer is a viewer if the viewability analysis value of the detected person is larger than the threshold, and is not a viewer if the threshold is smaller than the threshold. Is determined. If this threshold is 40, for example, it is determined that the person 33a is a viewer and the person 33b is not a viewer. That is, it is determined that the viewer exists only in the divided area 35a.

  A poster on which a person's face is printed, a wrinkle on clothes, a wall pattern, or the like is recognized as a person when it is not actually a person when the person detection unit 22 detects the person from the captured image. There is. On the other hand, it is detected as a person by the person detection unit 22 by determining whether or not the person detected as described above is a viewer, but a still object that is not actually a person is captured image. Even if it is included, it is possible to distinguish between an actual person and those that are not.

  Returning to FIG. 2, the direction determining unit 25 determines the screen direction of the display screen 13 based on the position of the person determined by the viewer determining unit 24 as the viewer.

  FIG. 6 is a diagram showing the relationship between the screen direction and the divided areas in the liquid crystal display device according to the first embodiment. As shown in FIG. 6, the screen direction of the display screen 13 is associated with each divided region, and is determined depending on which divided region the viewer is in. That is, the screen direction of the display screen 13 is the center direction 40a when the viewer exists in the divided area 41a, the right direction 40b when the viewer exists in the divided area 41b, and the left direction when the viewer exists in the divided area 41c. 40c. In FIG. 6, since the viewer exists in the divided area 41c, the screen direction of the display screen 13 is determined as the left direction 40c. When a viewer is present in a plurality of divided areas, the position may be an intermediate position between the divided areas. At this time, weighting may be performed based on the viewability analysis value.

  The drive control unit 26 controls the rotation of the rotary stand 12 so as to rotate the display screen 13 in any one of the central direction 40a, the right direction 40b, and the left direction 40c determined by the direction determination unit 25. . The rotation angle when rotating to the right or left is set in advance as an angle of the right direction 40b or the left direction 40c with respect to the central direction 40a.

  The relationship between the screen direction for rotating the display screen 13 and the divided areas is not limited to that shown in FIG. That is, the number of divided areas may be increased in the horizontal direction, and the screen direction may be newly set according to each divided area. In this way, the display screen 13 can be directed to the viewer more accurately.

  In addition, while the display screen 13 is rotating, analysis by the viewability analysis unit 23, determination by the viewer determination unit 24, and determination of the screen direction by the direction determination unit 25 are performed at any time. Continue to rotate until Further, the drive control unit 26 determines the rotation direction and time from the screen direction of the display screen 13 determined by the direction determination unit 25, and after rotating the determined time continuously to the right or left, stops the rotation. Control may be performed. Further, the rotary stand 12 is provided with means for acquiring the direction in which the display screen 13 is facing, such as a rotary encoder, and the right or left until the direction in which the display screen 13 is facing and the direction in which the display screen 13 should be directed coincide. You may control so that it may rotate.

  Next, the control procedure of the information processing apparatus 14 is shown. FIG. 7 is a flowchart showing a control procedure of the information control apparatus in the video display apparatus according to Embodiment 1.

  First, the imaging processing unit 21 acquires a captured image (S11). Next, the person detection unit 22 detects the face of the person from the acquired captured image, and detects the position of the person, the size of the face, and the orientation of the face (S12). Then, the viewability analysis unit 23 calculates a viewability analysis value for each person detected in step S12 (S13). Next, the viewability analysis unit 23 calculates the motion amount of the person (S14), and weights the viewability analysis value according to the calculated motion amount (S15). Next, the viewer determination unit 24 determines whether the detected person is a viewer based on the weighted viewability analysis value (S16).

  Next, the direction determination unit 25 determines the direction in which the display screen 13 is rotated based on the position of the person determined to be the viewer (S17). Next, the drive control unit 26 determines whether or not the determined direction of rotating the display screen 13 is a central direction with respect to the current screen direction of the display screen 13 (S18). If it is determined that the direction is the center direction (S18: YES), the drive control unit 26 controls the rotary stand 12 so as not to rotate the display screen 13 (S19), and ends the process.

  On the other hand, when it is determined that the direction is not the central direction (S18: NO), the drive control unit 26 determines whether or not the determined direction to rotate the display screen 13 is the right direction (S20). Here, when it is determined that the direction is the right direction (S20: YES), the drive control unit 26 controls the rotary stand 12 to rotate the display screen 13 to the right (S21), and ends the process. If it is not determined that the direction is the right direction (S20: NO), the drive control unit 26 controls the rotary stand 12 to rotate the display screen 13 to the left (S22), and ends the process.

  The above process is repeatedly performed at the same cycle as the imaging cycle of the imaging device 11. Note that the processing cycle of the information processing apparatus 14 may be performed at a cycle longer than the imaging cycle, such as once per N (N is an integer of 2 or more) captured images. Further, the processing cycle does not have to be constant. For example, while the display screen 13 is rotating to the right or left, it may be performed with a shorter cycle than when the display screen 13 is not rotating.

  According to the video display device of Embodiment 1, the viewability analysis value is weighted according to the amount of movement of the person, and whether or not the person detected based on the weighted viewability analysis value is a viewer. However, even if a still object that is not actually a person is included in the captured image, the influence of the display screen 13 is reduced appropriately. The screen direction can be determined.

  In addition, since the viewability analysis value of the person is calculated based on the direction of the person's face, even if a person who does not look at the display screen 13 is included in the captured image. The screen direction of the display screen 13 can be determined appropriately.

  Further, since the viewability analysis value of the person is calculated based on the angle formed by the orientation of the person's face and the perpendicular of the display screen 13, the angle θ is a pair with the orientation of the person's face in the captured image. Therefore, the calculation amount necessary for calculating the angle θ is small, and the possibility can be easily analyzed.

  In the first embodiment, the analysis of the possibility that the person is watching the video based on the angle formed by the perpendicular of the display screen 13 and the direction of the person's face has been described. Is not limited to this.

  FIG. 8 is a top view showing a method of determining the angle θ in the first modification of the video display device according to the first embodiment. In this modification, an angle formed by a line 36 from the center of the face to the center of the display screen 13 and a line 32 indicating the direction of the face is an angle θ. By doing so, it is possible to analyze that the person who exists in the center of the display screen 13 and faces the direction of the display screen has a higher possibility that the person is viewing the video. When a person is viewing the display screen 13, the person in the center can be given priority.

  FIG. 9 is a top view showing a method for determining the angle θ in the second modification of the video display device according to the first embodiment. In this modification, of the lines 37a, 37b and 37c from the center of the face to the display screen 13, the line 37a having the smallest angle with the line 32 indicating the face direction and the line 32 indicating the face direction are shown. Is the angle θ. In this way, if the person is facing the direction of the display screen 13, θ = 0, so that the person who is facing the direction of the display screen 13 can view the video regardless of the position. It is possible to analyze that there is a high possibility.

  In the first embodiment, the two-dimensional divided area is shown in FIG. 6, but the divided area is not limited to this.

  FIG. 10 shows a modified example of the divided region in the video display device according to the first embodiment, where (a) shows a rectangular parallelepiped and (b) shows a sector-shaped divided region. In these modified examples, the depth direction of a person is taken into consideration by setting a three-dimensional divided region in a pseudo manner. The three-dimensional divided area is set by generating a divided area divided in the vertical direction with respect to the display screen 13. Further, the screen direction is further subdivided and set in accordance with each divided region divided in the vertical direction. Then, the distance between the display screen and the viewer is calculated from the size of the person's face in the acquired captured image, and the viewer is divided into any of the divided areas divided in the vertical direction with respect to the display screen 13 from the calculated distance. Ask if there exists. In this way, by setting a divided area in consideration of the distance between the display screen 13 and the viewer, and determining the screen direction according to the distance of the viewer, the display screen 13 can be directed more accurately toward the viewer. Can do.

  In the first embodiment, the absolute value of the motion vector is used as the motion amount. However, the method for determining the motion amount is not limited to this. Instead of calculating the motion vector, using the captured image of the current frame and the captured image of the previous frame, the pixel value of the previous frame at the position of the person detected from the captured image of the current frame is calculated. The degree of difference may be the amount of movement. The degree of difference between pixel values is obtained from an average value of squares of differences in luminance values or a normalized correlation coefficient. Because the viewer has movement, the degree of difference in pixel values is large, but the poster on which the person's face is printed is stationary, so the degree of difference in pixel values is small. Therefore, even in this way, it is possible to distinguish between the viewer and the poster on which the face of the person is printed.

  Instead of calculating the motion vector, the absolute value of the difference between the position of the person detected from the captured image of the current frame and the position of the person detected from the captured image of the previous frame is used as the amount of motion. If the absolute value is greater than or equal to a predetermined threshold, the amount of motion may be set to zero. Since the viewer is not completely stationary and has a small movement, the absolute value of the difference in position is a small value that is not zero. On the other hand, since the poster on which the human face is printed is completely stationary, the absolute value of the position difference is zero. On the other hand, if the position difference is erroneously calculated between the position of one person and the position of another person, the calculated absolute value is a large value. Therefore, by doing this, it is possible to discriminate between the viewer and the poster on which the face of the person is printed, and to reduce the influence when the motion amount is calculated between different persons.

Embodiment 2. FIG.
FIG. 11 is a block diagram illustrating a configuration of the information processing apparatus in the video display apparatus according to the second embodiment. As shown in FIG. 11, the information processing apparatus 14 of the second embodiment further includes a history holding unit 27 in addition to the configuration of the first embodiment.

The history holding unit 27 holds the history of the viewer determination unit 24 in the past certain period. When the imaging device 11 acquires an image in a dim or bad lighting environment such as backlight, when the person detection unit 22 detects a person from the captured image, an area that is actually a face cannot be identified as a face. As a result, there is a case where there is no person who is determined as a viewer by the viewer determination unit 24. On the other hand, the position where the viewer views the video display device is often almost the same position, for example, when sitting on a sofa. Therefore, the direction determining unit 25 determines the screen direction of the display screen 13 based on the history held by the history holding unit 27 when there is no person determined to be a viewer by the viewer determining unit 24. .

  Next, the control procedure of the information processing apparatus 14 is shown. FIG. 12 is a flowchart illustrating a control procedure of the information processing apparatus in the video display apparatus according to the second embodiment. In the second embodiment, the viewer determination unit 24 determines whether there is a person determined to be a viewer in step S16 (S16B). If there is a person determined to be a viewer (S16B: YES), the process proceeds to step S17. On the other hand, when there is no person determined to be a viewer (S16B: NO), the direction determining unit 25 determines the direction in which the display screen is directed based on the history held in the history holding unit 27 (S17B). ). Other than the above, the second embodiment is the same as the first embodiment.

  According to the second embodiment, when there is no person determined to be a viewer by the viewer determining unit 24, the direction determining unit 25 displays the display screen 13 based on the history held in the history holding unit 31. Therefore, even when a person's face cannot be recognized, the influence is reduced, and the screen direction of the display screen 13 can be appropriately determined.

  The video display device of the present invention can be applied to a television receiver, digital signage, and the like. The configurations of the above embodiments can be combined with each other.

DESCRIPTION OF SYMBOLS 11 Imaging device 13 Display screen 21 Imaging processing part 22 Person detection part 23 Viewability analysis part 24 Viewer determination part 25 Direction determination part 26 Drive control part 27 History holding part 31 Perpendicular of display screen 32 Line 36 which shows face direction Lines from the center of the face to the center of the display screen 37a, 37b, 37c Lines from the center of the face to the display screen 100 Video display device

Claims (5)

A display screen for displaying images;
Imaging means for capturing an image of the front of the display screen and acquiring an image;
Person detecting means for detecting a person from the acquired image;
The motion amount of the detected person is calculated, and an analysis value indicating the possibility that the person is viewing the video is calculated based on the face direction of the person, and the analysis is performed according to the motion amount. Viewability analysis means for weighting the values;
Viewer determination means for determining whether or not the detected person is a viewer of the display screen based on the weighted analysis value;
Direction determining means for determining a screen direction of the display screen based on a position of a person determined to be a viewer by the viewer determining means;
A video display device comprising: driving means for rotationally driving the display screen in the screen direction determined by the direction determining means. A history holding means for holding a history of determination results of the viewer determination means;
The said direction determination means determines the screen direction of the said display screen based on the said log | history, when the person determined to be a viewer by the said viewer determination means does not exist. Video display device.   The video display device according to claim 1, wherein the viewability analyzing unit calculates the analysis value based on an angle formed by a perpendicular of the display screen and a line indicating the face direction. .   2. The viewability analyzing unit calculates the analysis value based on an angle formed by a line from the center of the face toward the center of the display screen and a line indicating the direction of the face. Or the video display apparatus of 2.   The viewability analysis means includes a line having a minimum angle with a line indicating the face direction and a line indicating the face direction, among lines extending from the center of the face to the display screen. The video display device according to claim 1, wherein the analysis value is calculated based on a corner.

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