Patent Publication Number: US-2023133054-A1

Title: Video generation device, video generation method, and program

Description:
TECHNICAL FIELD 
     The present invention relates to a technology that provides illusory motion to an object which is stationary. 
     BACKGROUND ART 
     A technology of providing motion impression to an object which is stationary by projecting grayscale motion information onto the object which is stationary from a projector has been known (Non-Patent Literature 1). Another technology of presenting an object which is stationary as if the object were moving by placing the object bordered with a white-black outline line on a blinking background has been known (Non-Patent Literature 2). 
     CITATION LIST 
     Non-Patent Literature 
     
         
         Non-Patent Literature 1: Takahiro Kawabe, “Danswing papers”, SA′ 18 Posters, Dec. 4-7, 2018, Tokyo, Japan. 
         Non-Patent Literature 2: Takahiro Kawabe, Taiki Fukiage, Masataka Sawayama, and Shinya Nishida, “Deformation Lamps: A Projection Technique to Make Static Objects Perceptually Dynamic”, ACM Transactions on Applied Perception, Vol. 13, No. 2, Article 10, March 2016. 
       
    
     SUMMARY OF THE INVENTION 
     Technical Problem 
     However, in Non-Patent Literature 1, the luminance of an object on which grayscale motion information is placed is different from the original luminance of the object. In Non-Patent Literature 2, since an outline line needs to be provided to an object, the appearance of the object potentially degrades. 
     The present invention is made in view of the above-described problem and intended to provide illusory motion to an object without changing the luminance and color of the object. 
     Means for Solving the Problem 
     To solve the above-described problem, a video including a stationary object region and a background region other than the stationary object region is generated. The background region includes a striped-texture region adjacent to the outline of the stationary object region, and a striped texture having a striped luminance pattern moves in a direction having a component orthogonal to the outline in the striped-texture region. 
     Effects of the Invention 
     Accordingly, it is possible to provide illusory motion to an object in a stationary object region without changing the luminance nor color of the object. 
    
    
     
       BRIEF DESCRIPTION OF DRAWINGS 
         FIG.  1    is a block diagram exemplarily illustrating a functional configuration of a video generation device of an embodiment. 
         FIGS.  2 A and  2 B  are block diagrams exemplarily illustrating a functional configuration of a video generation unit in  FIG.  1   . 
         FIG.  3    is a block diagram exemplarily illustrating a functional configuration of the video generation unit in  FIG.  1   . 
         FIG.  4    is a diagram exemplarily illustrating a video generated in the embodiment. 
         FIGS.  5 A to  5 D  are diagrams exemplarily illustrating a video generated in the embodiment. 
         FIGS.  6 A to  6 D  are diagrams exemplarily illustrating a video generated in the embodiment. 
         FIGS.  7 A to  7 D  are diagrams exemplarily illustrating a video generated in the embodiment. 
         FIGS.  8 A to  8 C  are diagrams exemplarily illustrating a video generated in the embodiment. 
         FIG.  9    is a diagram exemplarily illustrating a video generated in the embodiment. 
         FIGS.  10 A to  10 D  are diagrams exemplarily illustrating a video generated in the embodiment. 
         FIG.  11    is a diagram exemplarily illustrating a video generated in the embodiment. 
         FIG.  12    is a diagram exemplarily illustrating a video generated in the embodiment. 
         FIG.  13    is an enlarged view of  FIG.  12   . 
         FIG.  14    is a diagram exemplarily illustrating a hardware configuration of the video generation device of the embodiment. 
     
    
    
     DESCRIPTION OF EMBODIMENTS 
     Embodiments of the present invention will be described below with reference to the accompanying drawings. 
     First Embodiment 
     In the present embodiment, a moving striped texture is presented on the background of an object which is stationary to provide visual effects of movement and deformation to the object. 
     As exemplarily illustrated in  FIG.  1   , a video generation device  1  of the present embodiment includes a control unit  11 , a still image acquisition unit  12 , and a video generation unit  14 , generates a video by performing processing under control of the control unit  11 , and outputs the generated video to a presentation device  51 . As exemplarily illustrated in  FIG.  2 A , the video generation unit  14  of the present embodiment includes an outline extraction unit  142 , a striped-texture generation unit  143 , and a synthesis unit  144 . 
     &lt;Still Image Acquisition Unit  12 &gt; 
     The still image acquisition unit  12  acquires a still image. The still image acquisition unit  12  may generate a predetermined still image, may generate a still image based on a condition (for example, shape, size, position, or luminance) input from the outside, may acquire a still image input from the outside, or may obtain a still image by capturing a real object. The shape of the still image is not limited but may be any shape in which the outline (edge) of the still image is a straight line or a curved line. The luminance of the still image is desirably uniform or substantially uniform. In other words, the still image desirably has no texture. This is because, with a texture, it appears as if only the outline moved (the vicinity of the texture stops). However, with a texture in the still image, it is possible to obtain an illusion effect to some extent. 
     &lt;Video Generation Unit  14 &gt; 
     The still image obtained by the still image acquisition unit  12  is input to the video generation unit  14 . Note that, inputting of an image or a video means inputting of information for specifying the image or the video. Similarly, outputting of an image or a video means outputting of information for specifying the image or the video. The video generation unit  14  generates and outputs a video including a stationary object region as a region of the input still image and a background region other than the stationary object region. However, the background region includes a striped-texture region adjacent to the outline of the stationary object region, and a striped texture having a striped luminance pattern (pattern including a luminance contour line) moves in a direction having a component orthogonal to the outline in the striped-texture region. The striped-texture region may be the entire background region or part of the background region. The striped luminance pattern is, for example, a pattern having a shape following the outline of the stationary object region (pattern including a luminance contour line in a shape following the outline of the stationary object region). The “shape following the outline” means a shape similar to the outline, a shape substantially similar to the outline, and a shape analogous to the outline. A specific example of processing at the video generation unit  14  will be described later. The visual system of a viewer of such a video integrates the moving striped texture presented in the background region with the stationary object region which is stationary. Accordingly, illusion is provided as if the still image in the stationary object region were moving. Since the moving striped texture is presented in the background region of the stationary object region, illusory motion can be provided to the stationary object region without visually changing the luminance and color of the stationary object region. Furthermore, the outline line of the stationary object region does not need to be physically changed. Moreover, the striped-texture region only need to be adjacent to the outline of the stationary object region, and the width of the stationary object region has no limitations, which leads to a high designing freedom. Specific examples of a video generated in this manner are described below with reference to  FIGS.  4  to  13   . 
     Video Example 1 
     For example, the video generation unit  14  generates and outputs a video  100  including a stationary object region  111  and background regions  121  and  122  other than the stationary object region  111  as exemplarily illustrated in  FIG.  4   . The background region  121  includes a striped-texture region adjacent to an outline  1111  of the stationary object region  111 , and the background region  122  includes a striped-texture region adjacent to the outline  1112  of the stationary object region  111 . In the example illustrated in  FIG.  4   , the entire background region  121  is a striped-texture region, and the entire background region  122  is a striped-texture region. In the striped-texture region of the background region  121 , a striped texture having a luminance pattern in a shape following the outline  1111  moves in a direction D 1  having a component orthogonal to the outline  1111 . In the striped-texture region of the background region  122 , a striped texture having a luminance pattern in a shape following the outline  1112  moves in a direction D 2  having a component orthogonal to the outline  1112 . 
     The striped texture having a luminance pattern in a shape following any of the outlines  1111  and  1112  is, for example, a texture in which luminance distribution in a shape following the outlines  1111  and  1112  is periodically repeated. In the example illustrated in  FIG.  4   , the outlines  1111  and  1112  are straight or substantially straight. In this case, the striped texture having a luminance pattern in a shape following any of the outlines  1111  and  1112  is, for example, a texture (for example, periodically repeated texture) that has luminance distribution in which the luminance is same on a straight line, the luminance distribution being repeated with the luminance continuously changed in a direction orthogonal or substantially orthogonal to the straight line. In other words, the striped texture in the background region  121  temporally changes with the luminance phase being continuously different among points in a direction orthogonal or substantially orthogonal to a straight line in a shape following the outline  1111 . The striped texture in the background region  122  temporally changes with the luminance phase being continuously different among points in a direction orthogonal or substantially orthogonal to a straight line in a shape following the outline  1112 . The luminance of the striped texture in the background region  121  continuously differs with continuous position difference in a direction having a component orthogonal to the outline  1111  (for example, direction orthogonal or substantially orthogonal to a straight line  1211  in a shape following the outline  1111 ). Similarly, the luminance of the striped texture in the background region  122  continuously differs with continuous position difference in a direction having a component orthogonal to the outline  1112  (for example, direction orthogonal or substantially orthogonal to a straight line  1221  in a shape following the outline  1112 ). For example, the luminance values of the striped textures in the background regions  121  and  122  have sin waveforms at positions in the directions. 
     The moving direction of the striped texture in the background region  121  (the direction D 1  having a component orthogonal to the outline  1111 ) is desirably orthogonal or substantially orthogonal to the straight line  1211  as a luminance contour line of the striped texture in a shape following the outline  1111 . Similarly, the moving direction of the striped texture in the background region  122  (the direction D 2  having a component orthogonal to the outline  1112 ) is desirably orthogonal or substantially orthogonal to the straight line  1221  as a luminance contour line of the striped texture in a shape following the outline  1112 . However, these conditions do not limit the present invention. 
     The luminance at the outline of the stationary object region  111  or in the vicinity of the outline of the stationary object region  111  is desirably between the upper and lower limits of the luminance of the striped texture in the background region  121  and between the upper and lower limits of the luminance of the striped texture in the background region  122 . Accordingly, the above-described illusion can be more strongly perceived. However, even when this condition is not satisfied, the above-described illusion can be perceived as long as the difference between the luminance of the striped texture in each of the background regions  121  and  122  and the luminance at the outline of the stationary object region  111  or in the vicinity of the outline of the stationary object region  111  periodically changes. In any case, when the luminance in the background regions  121  and  122  in the vicinities of the outlines  1111  and  1112  of the stationary object region  111  is close to the luminance of the stationary object region  111 , it is perceived as if the outlines  1111  and  1112  were pulled toward the background regions  121  and  122 . Specifically, when the boundary between each of the outlines  1111  and  1112  and the corresponding one of the background regions  121  and  122  in the vicinities of the outlines  1111  and  1112  cannot be seen by the viewer in a lower spatial frequency band related to perception of image motion, it is perceived as if the outlines  1111  and  1112  were pulled toward the background regions  121  and  122 . However, the spatial frequency band is affected by an individual difference such as eyesight. 
     It is desirable that the maximum value of the luminance of the striped texture in each of the background regions  121  and  122  is the luminance of white, and the minimum value of the luminance of the striped texture in each of the background regions  121  and  122  is the luminance of black. However, the maximum value of the luminance of the striped texture in each of the background regions  121  and  122  may be lower than the luminance of white, and the minimum value of the luminance of the striped texture in each of the background regions  121  and  122  may be higher than the luminance of black. 
     The angle between the striped texture in the background region  121  and the outline  1111  (angle between the straight line  1211  and the outline  1111 ) is represented by θ 1 , and the angle between the striped texture of the striped-texture region in the background region  122  and the outline  1112  (angle between the straight line  1221  and the outline  1112 ) is represented by θ 2 . The angles may satisfy θ 1 =θ 2  or θ 1  #θ 2 . 
     A perceived visual effect differs with θ 1 , θ 2 , D 1 , and D 2 . For example, the striped textures in the background regions  121  and  122  move in directions perpendicular or substantially perpendicular to the outlines  1111  and  1112  of the stationary object region  111  (the right or left side in  FIG.  4   ) when θ 1  and θ 2  are zero or close to zero, D 1  and D 2  are identical or approximate to each other, and the phases of the striped textures in the background regions  121  and  122  are identical or approximate to each other. Specifically, the phase of the luminance is identical or substantially identical between the background regions  121  and  122  in the vicinities of the outlines  1111  and  1112  (in other words, the luminance is identical or substantially identical between the background regions  121  and  122  in the vicinities of the outlines  1111  and  1112 . The striped textures are positioned near the outlines  1111  and  1112  and parallel or substantially parallel to the outlines  1111  and  1112 ). In this case, it appears as if the stationary object region  111  swung to right and left. The spatial frequency of each striped texture is desirably at least 6.4 cycles per degree. However, a visual effect at a certain level occurs with the lower spatial frequency of the striped texture although the effect is lower. The moving speed of the striped texture is not restricted, but larger illusion can be perceived as the moving speed of the striped texture is higher. However, a too high moving speed of the striped texture potentially causes light-induced seizure, and thus the moving speed of the striped texture is desirably equal to or lower than 4 Hz. 
     The angles θ 1  and θ 2  may be larger or smaller than zero. In this case, the striped textures in the background regions  121  and  122  have luminance patterns tilted relative to tangent lines of the outlines  1111  and  1112  and move in directions tilted relative to the tangent lines of the outlines  1111  and  1112 . When the striped textures are tilted relative to the outlines  1111  and  1112 , it can be perceived as if the stationary object region  111  rippled (in particular, a visual effect that the outlines  1111  and  1112  deform as if rippling were provided). However, such a visual effect decreases when the absolute values of θ 1  and θ 2  are too large and the tilts are too large. Optimum values of the absolute values of θ 1  and θ 2  are equal to or larger than 1° and equal to or smaller than 4°. However, this does not limit the present invention. In addition, the visual effect can be more significantly perceived as the spatial frequencies (spatial frequencies in directions orthogonal or substantially orthogonal to the straight lines  1211  and  1221 , respectively) of the striped textures in the background regions  121  and  122  are higher (strips are finer), but the visual effect more largely decreases as θ 1  and θ 2  increase. Thus, it is desirable to decrease the upper limit value of the absolute values of θ 1  and θ 2  as the spatial frequencies of the striped textures in the background regions  121  and  122  are higher. Specifically, it is desirable: when the striped texture in the background region  121  has a luminance pattern at a first spatial frequency, the upper limit of the tilt θ 1  of the luminance pattern relative to the tangent line of the outline is a first upper limit value; when the striped texture in the background region  121  has a luminance pattern at a second spatial frequency, the upper limit of the tilt θ 1  of the luminance pattern relative to the tangent line of the outline is a second upper limit value; the first spatial frequency is higher than the second spatial frequency; and the first upper limit value is smaller than the second upper limit value. Similarly, it is desirable: when the striped texture in the background region  122  has a luminance pattern at a first spatial frequency, the upper limit of the tilt θ 2  of the luminance pattern relative to the tangent line of the outline is a first upper limit value; when the striped texture in the background region  122  has a luminance pattern at a second spatial frequency, the upper limit of the tilt θ 2  of the luminance pattern relative to the tangent line of the outline is a second upper limit value; the first spatial frequency is higher than the second spatial frequency; and the first upper limit value is smaller than the second upper limit value. The effect is maximum when the spatial frequencies at parts where the stationary object region  111  contacts the striped textures in the background regions  121  and  122  are 0.5 cycles per degree. When the striped textures are tilted relative to the outlines  1111  and  1112 , the moving speed of each striped texture is not restricted, but larger illusion can be perceived as the moving speed of the striped texture is higher. However, a too high moving speed of the striped texture potentially causes light-induced seizure, and thus the moving speed of the striped texture is desirably equal to or lower than 4 Hz. 
       FIGS.  5 A to  8 C  exemplarily illustrate the video  100  in which the spatial frequencies and angles θ 1  and θ 2  of the striped textures are set as described below. 
       FIG.  5 A : the wavelengths of the striped textures are 4 pixels and θ 1  and θ 2  are 0′. 
       FIG.  5 B : the wavelengths of the striped textures are 4 pixels and θ 1  and θ 2  are 1′. 
       FIG.  5 C : the wavelengths of the striped textures are 4 pixels and θ 1  and θ 2  are 2°. 
       FIG.  5 D : the wavelengths of the striped textures are 4 pixels and θ 1  and θ 2  are 4°. 
       FIG.  6 A : the wavelengths of the striped textures are 4 pixels and θ 1  and θ 2  are 8°. 
       FIG.  6 B : the wavelengths of the striped textures are 8 pixels and θ 1  and θ 2  are 0°. 
       FIG.  6 C : the wavelengths of the striped textures are 8 pixels and θ 1  and θ 2  are 1°. 
       FIG.  6 D : the wavelengths of the striped textures are 8 pixels and θ 1  and θ 2  are 2°. 
       FIG.  7 A : the wavelengths of the striped textures are 8 pixels and θ 1  and θ 2  are 4°. 
       FIG.  7 B : the wavelengths of the striped textures are 8 pixels and θ 1  and θ 2  are 8°. 
       FIG.  7 C : the wavelengths of the striped textures are 16 pixels and θ 1  and θ 2  are 0°. 
       FIG.  7 D : the wavelengths of the striped textures are 16 pixels and θ 1  and θ 2  are 1°. 
       FIG.  8 A : the wavelengths of the striped textures are 16 pixels and θ 1  and θ 2  are 2°. 
       FIG.  8 B : the wavelengths of the striped textures are 16 pixels and θ 1  and θ 2  are 4°. 
       FIG.  8 C : the wavelengths of the striped textures are 16 pixels and θ 1  and θ 2  are 8°. 
     Video Example 2 
     The striped-texture regions may be narrow regions adjacent to the outlines  1111  and  1112  of the stationary object region  111 . Specifically, since illusion of the present embodiment uses the striped textures in the vicinity of the outlines  1111  and  1112  of the stationary object region  111 , the striped-texture regions in which the luminance varies may be only in the vicinity of the outlines  1111  and  1112 . 
     For example, the video generation unit  14  may generate and output a video  200  including the stationary object region  111  and background regions  221  and  222  other than the stationary object region  111  as exemplarily illustrated in  FIG.  9   . The background region  221  includes a striped-texture region  221   a  (region sandwiched by the outline  1111  and a straight edge  2211  parallel to the outline  1111 ) adjacent to the outline  1111  of the stationary object region  111 . The background region  222  includes a striped-texture region  222   a  (region sandwiched between the outline  1112  and a straight edge  2221  parallel to the outline  1112 ) adjacent to the outline  1112  of the stationary object region  111 . A striped texture having a luminance pattern in a shape following the outline  1111  moves in the direction D 1  having a component orthogonal to the outline  1111  in the striped-texture region  221   a  of the background region  221 . A striped texture having a luminance pattern in a shape following the outline  1112  moves in the direction D 2  having a component orthogonal to the outline  1112  in the striped-texture region  221   a  of the background region  222 . The video  200  is same as the above-described example of the video  100  except that the striped-texture regions  221   a  and  222   a  of the video  200  are narrow regions adjacent to the outlines  1111  and  1112  of the stationary object region  111 . In this manner, it is important that the striped-texture regions  221   a  and  222   a  contact the outlines  1111  and  1112  of the stationary object region  111 , and the striped-texture regions  221   a  and  222   a  do not need to be across the entire background regions  221  and  222 . Instead, a larger illusion effect is perceived when the striped-texture regions  221   a  and  222   a  are narrow. This is because when the striped-texture regions  221   a  and  222   a  are too wide, it is likely to be perceived as if the background of the stationary object region  111  were moving rather than as if the vicinity of the stationary object region  111  were moving. When the striped-texture regions  221   a  and  222   a  are too narrow, the striped textures are difficult to visually recognize, and accordingly, the illusion effect decreases. The striped-texture regions  221   a  and  222   a  are desirably regions as narrow as possible (regions having narrow widths in a direction orthogonal to the outlines  1111  and  1112 ) as long as the striped textures can be visually recognized. In this case, it is desirable that the striped textures of one period or more can be visually recognized in at least the striped-texture regions  221   a  and  222   a.    
       FIGS.  10 A to  11    exemplarily illustrate the video  200  in which the spatial frequencies and angles θ 1  and θ 2  of the striped textures are set as described below. Note that the “widths of the striped-texture regions  221   a  and  222   a ” means the widths of the striped-texture regions  221   a  and  222   a  in the direction orthogonal to the outlines  1111  and  1112 . 
       FIG.  10 A : the widths of the striped-texture regions  221   a  and  222   a  are each 1 pixel, the wavelengths of the striped textures are 8 pixels, and θ 1  and θ 2  are 2°. 
       FIG.  10 B : the widths of the striped-texture regions  221   a  and  222   a  are each 2 pixels, the wavelengths of the striped textures are 4 pixels, and θ 1  and θ 2  are 2°. 
       FIG.  10 C : the widths of the striped-texture regions  221   a  and  222   a  are each 4 pixels, the wavelengths of the striped textures are 4 pixels, and θ 1  and θ 2  are 2°. 
       FIG.  10 D : the widths of the striped-texture regions  221   a  and  222   a  are each 8 pixels, the wavelengths of the striped textures are 4 pixels, and θ 1  and θ 2  are 2°. 
       FIG.  11   : the widths of the striped-texture regions  221   a  and  222   a  are each 16 pixels, the wavelengths of the striped textures are 4 pixels, and θ 1  and θ 2  are 2°. 
     Video Example 3 
     The outline of the stationary object region may be a curved line. For example, the video generation unit  14  may generate and output a video  300  including stationary object regions  311   a  and  311   b  and a background region  320  other than the stationary object regions  311   a  and  311   b  as exemplarily illustrated in  FIGS.  12  and  13   . The background region  320  includes a striped-texture region  321   a  (region surrounded by the curved outline  3111   a  and a curved edge  3211   a  following the outline  3111   a ) adjacent to an outline  3111   a  of the stationary object region  311   a , and a striped-texture region  321   b  (region surrounded by the curved outline  3111   b  and a curved edge  3211   b  following the outline  3111   b ) adjacent to an outline  3111   b  of the stationary object region  311   b . A striped texture having a curved luminance pattern following the outline  3111   a  moves in a direction having a component orthogonal to the outline  3111   a  (component orthogonal to the tangent line of the outline  3111   a ) in the striped-texture region  321   a . A striped texture having a curved luminance pattern following the outline  3111   b  moves in a direction having a component orthogonal to the outline  3111   b  (component orthogonal to the tangent line of the outline  3111   b ) in the striped-texture region  321   b . The angle between a tangent line  3111   ab  of the outline  3111   a  and a tangent line  321   ab  of a luminance contour line of the striped texture in the striped-texture region  321   a  on a straight line La orthogonal to the tangent line  3111   ab  of the outline  3111   a  of the stationary object region  311   a  is represented by θ 1  ( FIG.  13   ). Similarly, the angle between a tangent line  3111   bb  of the outline  3111   b  and a tangent line  321   bb  of a luminance contour line of the striped texture in the striped-texture region  321   b  on a straight line Lb orthogonal to the tangent line  3111   bb  of the outline  3111   b  of the stationary object region  311   b  is represented by θ 2 . The angles θ 1  and θ 2  may be zero, smaller than zero, or larger than zero. The angles may satisfy θ 1 =θ 2  or θ 1  #θ 2 . The video  300  is same as the above-described examples of the videos  100  and  200  except that the outlines  3111   a  and  3111   b  of the stationary object regions  311   a  and  311   b  of the video  300  are curved lines, the striped-texture regions  321   a  and  321   b  are narrow regions adjacent to the outlines  3111   a  and  3111   b , and striped textures having curved luminance patterns following the outlines  3111   a  and  3111   b  move in the above-described direction in the striped-texture regions  321   a  and  321   b . Note that  FIG.  12    is an example in which the stationary object regions  311   a  and  311   b  have heart shapes, the widths (widths in a direction orthogonal to the outlines  3111   a  and  3111   b ) of the striped-texture regions  321   a  and  321   b  are each 8 pixels, the wavelengths of the striped textures are 8 pixels, and the angles θ 1  and θ 2  of the striped textures relative to the outlines  3111   a  and  3111   b  are 0°. 
     Video Example 4 
     In Video Examples 1 and 2, the phases and motion directions (angles D 1  and D 2 ) of the striped textures in the background regions  121 ,  122 ,  221 , and  222  on the right and left sides of the stationary object region  111  may be able to be independently operated. For example, it can be presented as if the stationary object region  111  were scaled up and down or swung to right and left by independently operating the phases and motion directions of the striped textures in the background region  121  or  221  on the left side of the stationary object region  111  and the background region  122  or  222  on the right side thereof. For example, it is possible to generate illusion that the stationary object region  111  is scaled up and down when a striped texture moving to the left is presented in the background region  121  or  221  on the left side, a striped texture moving to the right is presented in the background region  122  or  222  on the right side, and the phases of these striped textures set to be identical. Moreover, it is possible to generate illusion that the stationary object region  111  is moving to right and left when a striped texture moving to the left is presented in the background region  121  or  221  on the left side, a striped texture moving to the right is presented in the background region  122  or  222  on the right side, and the phase difference between these striped textures are set closer to 180°. In addition, a plurality of striped-texture regions, the motion directions and phases of which can be independently operated may be provided in one background region (for example, the background region  121 ). The other feature is same as those in Video Examples 1 and 2. 
     Video Example 5 
     Video Examples 1 to 4 exemplarily describe striped textures each having a striped luminance pattern in a shape following the outline of a stationary object region. However, this does not limit the present invention. Specifically, the shape of the luminance pattern does not need to be a shape following the outline of the stationary object region as long as a striped texture in the background region has a striped luminance pattern (pattern including a luminance contour line). For example, the outline of the stationary object region may be a straight line and the luminance pattern of the striped texture may include a curved line, the outline of the stationary object region may be a curved line and the luminance pattern of the striped texture may include a straight line, or the outline of the stationary object region may be a curved line and the luminance pattern of the striped texture may be a curved line not similar to the outline of the stationary object region (curved line not in a shape following the outline). Alternatively, the outline of the stationary object region may include a straight line and a curved line and the luminance pattern of the striped texture may include a straight pattern and a curved pattern, the outline of the stationary object region may include a straight line and a curved line and the luminance pattern of the striped texture may include only a straight pattern, or the outline of the stationary object region may include a straight line and a curved line and the luminance pattern of the striped texture may include only a curved pattern. 
     &lt;&lt;Specific Example of Processing at Video Generation Unit  14 &gt;&gt; 
     A specific example of processing at the video generation unit  14  will be described below with reference to  FIG.  2 A . 
     A still image output from the still image acquisition unit  12  is input to the outline extraction unit  142  of the video generation unit  14 . The outline extraction unit  142  extracts the outline of the input still image and outputs the extracted outline to the striped-texture generation unit  143 . The striped-texture generation unit  143  sets, by using information of the outline of the input still image, a stationary object region that is a region of the still image and a background region that is a region other than the stationary object region as described above. In addition, the striped-texture generation unit  143  sets a striped-texture region in which a striped texture moves. Specifically, a partial region adjacent to the outline of the stationary object region may be set as the striped-texture region in the background region, or the entire background region may be set as the striped-texture region. In addition, the striped-texture generation unit  143  generates a video in which a striped texture moves by using predetermined striped texture information. For example, when the striped texture is a straight texture, information related to the luminance pattern (spatial frequency), luminance, contrast, angle relative to the stationary object region, motion direction, and speed of the striped texture is stored as the striped texture information in a non-illustrated storage unit in advance. The striped-texture generation unit  143  reads the striped texture information from the storage unit and generates a video in which the striped texture moves in the striped-texture region based on the read information. 
     (i) Case in which the Entire Background Region is the Striped-Texture Region 
     When the entire background region is the striped-texture region, the striped-texture generation unit  143  outputs, to the synthesis unit  144 , a video that includes the stationary object region and the background region other than the stationary object region and in which a generated striped texture moves in the striped-texture region, in other words, in the background region. The synthesis unit  144  receives the still image and the video. The synthesis unit  144  generates and outputs a synthesis video obtained by synthesizing the still image in the stationary object region of the video. 
     (ii) Case in which Part of the Background Region is the Striped-Texture Region 
     The striped-texture generation unit  143  outputs, to the synthesis unit  144 , a video that includes the stationary object region and the background region and in which a generated striped texture moves in the striped-texture region of the background region. The synthesis unit  144  receives the still image and the video that includes the stationary object region and the background region and in which the striped texture moves in the striped-texture region. The synthesis unit  144  generates and outputs a synthesis video obtained by synthesizing the still image in the stationary object region of the video. 
     Note that although the above description assumes that the striped-texture information is provided in advance, the striped-texture information may be generated based on the outline obtained by the outline extraction unit. The striped-texture information may be generated by any method as long as a striped-texture video described above in each &lt;Video Example&gt; can be generated based on the striped-texture information. 
     For example, there are exemplary combinations of the outline shape of the stationary object region and the luminance pattern shape of the striped texture as follows.
         The outline of the stationary object region is a straight line, and the luminance contour line of the luminance pattern of the striped texture is a straight line tilted relative to the outline of the stationary object region   The outline of the stationary object region is a straight line, and the luminance contour line of the luminance pattern of the striped texture is a curved line   The outline of the stationary object region is a curved line, and the luminance contour line of the luminance pattern of the striped texture is a curved line similar or substantially similar to the outline of the stationary object region   The outline of the stationary object region is a curved line, and the luminance contour line of the luminance pattern of the striped texture is a curved line not similar nor substantially similar to the outline of the stationary object region (for example, the luminance contour line of the luminance pattern of the striped texture is a curved line similar or substantially similar to the outline of the stationary object region and tilted relative to the outline of the stationary object region)       

     &lt;Presentation Device  51 &gt; 
     The presentation device  51  receives a synthesis video output from the video generation unit  14 . The presentation device  51  presents the synthesis video. For example, the presentation device  51  may display the synthesis video on a display (smartphone display or VR head-mounted display), may display the synthesis video on a smart glass, or may project the synthesis video on a screen. 
     [Modification 1 of First Embodiment] 
     Modification 1 of the first embodiment is a modification of the first embodiment and different from the first embodiment in that a video including a stationary object region and a background region is presented without being digitally synthesized with a still image. The other feature is same as that of the first embodiment. Hereinafter, difference from a matter described so far will be mainly described, an already described matter is denoted by the same reference number, and description thereof will be simplified. 
     As exemplarily illustrated in  FIG.  1   , a video generation device  1 ′ of the present modification includes the control unit  11 , the still image acquisition unit  12 , and a video generation unit  14 ′, generates a video by performing processing under control of the control unit  11 , and outputs the generated video to the presentation device  51 ′. As exemplarily illustrated in  FIG.  2 B , the video generation unit  14 ′ of the present embodiment includes the outline extraction unit  142  and a striped-texture generation unit  143 ′. 
     &lt;Still Image Acquisition Unit  12 &gt; 
     The same description as in the first embodiment applies. 
     &lt;Video Generation Unit  14 ′&gt; 
     The video generation unit  14 ′ generates and outputs a video including a stationary object region that is a region of an input still image and a background region other than the stationary object region. The video generation unit  14 ′ is different from the video generation unit  14  only in that the video generation unit  14 ′ does not synthesize the still image in the stationary object region. 
     &lt;&lt;Specific Example of Processing at Video Generation Unit  14 ′&gt;&gt; 
     Processing at the video generation unit  14 ′ will be described below with reference to  FIG.  2 B . 
     A still image output from the still image acquisition unit  12  is input to the outline extraction unit  142  of the video generation unit  14 ′. The outline extraction unit  142  extracts the outline of the input still image and outputs the extracted outline to the striped-texture generation unit  143 . The striped-texture generation unit  143  sets a stationary object region that is a region of the still image and a background region other than the stationary object region by using information of the outline of the input still image as described above. In addition, the striped-texture generation unit  143  sets a striped-texture region in which a striped texture moves. Specifically, a partial region adjacent to the outline of the stationary object region in the background region may be set as the striped-texture region, or the entire background region may be set as the striped-texture region. In addition, the striped-texture generation unit  143  generates a video in which a striped texture moves by using predetermined striped-texture information. 
     (i) Case in which the Entire Background Region is the Striped-Texture Region 
     When the entire background region is the striped-texture region, the striped-texture generation unit  143  outputs a video that includes the stationary object region and the background region other than the stationary object region and in which a generated striped texture moves in the striped-texture region, in other words, in the background region. 
     (ii) Case in which Part of the Background Region is the Striped-Texture Region 
     The striped-texture generation unit  143  outputs a video that includes the stationary object region and the background region and in which a generated striped texture moves in the striped-texture region of the background region. 
     The striped-texture generation unit  143  outputs the video that includes the stationary object region and the background region to the presentation device  51 ′. In addition, the still image is output to the presentation device  51 ′. 
     &lt;Presentation Device  51 ′&gt; 
     The presentation device  51 ′ receives the video and the still image output from the video generation unit  14 ′. The presentation device  51 ′ displays the video and the still image on different planes so that the still image overlaps the stationary object region. For example, one of the still image and the stationary object region is displayed on a display, and the other is displayed on a transmissive display disposed between the display and the viewer. Accordingly, the viewer can see an image in which the still image overlaps the stationary object region of the video. 
     [Modification 2 of First Embodiment] 
     Modification 2 of the first embodiment is a modification of the first embodiment or Modification 1 of the first embodiment and different from the first embodiment or Modification 1 of the first embodiment in that a striped-texture region and/or striped-texture information is set based on input information. The other feature is same as that of the first embodiment or Modification 1 of the first embodiment. 
     As exemplarily illustrated in  FIG.  1   , a video generation device  1 ″ includes the control unit  11 , the still image acquisition unit  12 , an input unit  13 ″, and a video generation unit  14 ″ (or video generation unit  14 ′″) of the present modification, generates a video by performing processing under control of the control unit  11 , and outputs the generated video to the presentation device  51  (or  51 ′). As exemplarily illustrated in  FIG.  2 A , the video generation unit  14 ″ of the present embodiment includes the outline extraction unit  142 , a striped-texture generation unit  143 ″, and the synthesis unit  144 . As exemplarily illustrated in  FIG.  2 B , the video generation unit  14 ′″ of the present embodiment includes the outline extraction unit  142  and the striped-texture generation unit  143 ″. 
     &lt;Still Image Acquisition Unit  12 &gt; 
     The same description as in the first embodiment applies. 
     &lt;Input Unit  13 ″&gt; 
     Setting information necessary for setting a striped-texture region, and/or striped-texture information is input to the input unit  13 ″. Examples of the setting information include the range and shape of the striped-texture region, and examples of the striped-texture information include the luminance pattern (spatial frequency) of a striped texture, the angle of the striped texture relative to a stationary object region, the motion direction and speed of the striped texture, and information indicating how the stationary object region is to be presented. Examples of the information indicating how the stationary object region is to be presented include information indicating that the stationary object region is to be presented as if the stationary object region swung to right and left, as if the stationary object region rippled, as if the stationary object region were scaled up and down, and as if the stationary object region expanded and contracted. When no setting information necessary for setting a striped-texture region is input or when the input setting information does not match the “information indicating how the stationary object region is to be presented”, a striped-texture region for generating intended illusion may be set based on the information indicating how the stationary object region is to be presented. The method of the setting and the method of determining whether the input setting information matches the “information indicating how the stationary object region is to be presented” are as described above. 
     A still image and setting information necessary for setting a striped-texture region are input to the video generation unit  14 ″ (or the video generation unit  14 ′″). The video generation unit  14 ″ (or the video generation unit  14 ′″) generates, based on the setting information, a video including a stationary object region that is a region of the input still image and a background region other than the stationary object region, and outputs the generated video. 
     &lt;&lt;Specific Example of Processing at Video Generation Unit  14 ″&gt;&gt; 
     Processing at the video generation unit  14 ″ will be described below with reference to  FIG.  2 A . 
     A still image output from the still image acquisition unit  12  is input to the outline extraction unit  142  of the video generation unit  14 ″. The outline extraction unit  142  extracts the outline of the input still image and outputs the extracted outline to the striped-texture generation unit  143 . The striped-texture generation unit  143 ″ sets a stationary object region that is a region of the still image and a background region other than the stationary object region as described in the first embodiment by using input setting information and information of the outline of the still image. The striped-texture generation unit  143 ″ also sets a striped-texture region in which a striped design moves as described in the first embodiment. However, the striped-texture region has characteristics specified by the setting information. The other feature is same as that of the video generation unit  14  of the first embodiment. 
     &lt;&lt;Specific Example of Processing at Video Generation Unit  14 ′″&gt;&gt; 
     Processing at the video generation unit  14 ′″ will be described below with reference to  FIG.  2 B . 
     A still image output from the still image acquisition unit  12  is input to the outline extraction unit  142  of the video generation unit  14 ′″. The outline extraction unit  142  extracts the outline of the input still image and outputs the extracted outline to the striped-texture generation unit  143 ″. The striped-texture generation unit  143 ″ sets a stationary object region that is a region of the still image and a background region other than the stationary object region as described above by using information of the outline of the input still image. The striped-texture generation unit  143 ″ also sets a striped-texture region in which a striped texture moves. However, the striped-texture region has characteristics specified by setting information. The other feature is same as that of the video generation unit  14 ′ of Modification 1 of the first embodiment. 
     &lt;Presentation Device  51  (or Presentation Device  51 ′)&gt; 
     The same description as in the first embodiment or Modification 1 of the first embodiment applies. 
     Second Embodiment 
     When a stationary object that is a real object is disposed in a stationary object region, a video that provides motion illusion to the stationary object may be generated. The real object is, for example, a stereoscopic or planar object made of paper, wood, metal, or other material. 
     As exemplarily illustrated in  FIG.  1   , a video generation device  2  of the present embodiment includes the control unit  11 , a still image acquisition unit  22 , and a video generation unit  24 , generates a video by performing processing under control of the control unit  11 , and outputs the generated video to the presentation device  51 . As exemplarily illustrated in  FIG.  3   , the video generation unit  24  of the present embodiment includes the outline extraction unit  142  and the striped-texture generation unit  143  (or  143 ″). 
     &lt;Still Image Acquisition Unit  22 &gt; 
     The still image acquisition unit  22  obtains a still image of a stationary object that is a real object by capturing the stationary object and outputs the obtained still image. 
     &lt;Video Generation Unit  24 &gt; 
     The video generation unit  24  receives the still image output from the still image acquisition unit  22 . The video generation unit  24  generates, by using the still image, a video including a background region as the background of a region in which a stationary object is disposed, and outputs the generated video. The background region includes a striped-texture region adjacent to the outline of a stationary object region, and a striped texture moves in a direction having a component orthogonal to the outline in the striped-texture region. The striped texture has, for example, a luminance pattern in a shape following the outline, but is not limited thereto. Processing at the video generation unit  24  is same as in Modification 1 of the first embodiment or a modification of Modification 1 in accordance with Modification 2 of the first embodiment except that the region in which the stationary object is disposed is set as the stationary object region and a still image is not output to the presentation device  51 ′ ( FIG.  3   ). When the striped texture does not have a luminance pattern in a shape following the outline, the region in which the stationary object is disposed does not necessarily need to be set as the stationary object region. Note that although the above description assumes that striped-texture information is provided in advance, the striped-texture information may be generated based on the still image captured by the still image acquisition unit. The striped-texture information may be generated by any method as long as a striped-texture video described above in each &lt;Video Example&gt; is generated based on the striped-texture information. 
     The presentation device  51  receives the video output from the video generation unit  24 . The presentation device  51  presents the video. For example, the presentation device  51  displays the video on a display. As described above, the displayed video includes the stationary object region and the background region other than the stationary object region. When the stationary object region is set, the above-described stationary object is disposed in the stationary object region to provide a visual effect as if the stationary object were moving. When the striped texture does not have a luminance pattern in a shape following the outline, the stationary object may be disposed at any position where at least part of the stationary object contacts the inside of the striped-texture region. 
     [Hardware Configuration] 
     The video generation devices  1 ,  1 ′,  1 ″, and  2  in the embodiments and modifications are each a device configured, for example, when a general-purpose or dedicated computer including a processor (hardware processor) such as a central processing unit (CPU), and a memory such as a random-access memory (RAM) or a read-only memory (ROM) executes a predetermined program. The computer may include one processor and one memory or may include a plurality of processors and a plurality of memories. The program may be installed on the computer or may be recorded in a ROM or the like in advance. Some or all processing units may be configured by using an electronic circuitry that achieves a processing function alone instead of an electronic circuitry, such as a CPU, that achieves a functional configuration by reading a program. An electronic circuitry included in one device may include a plurality of CPUs. 
       FIG.  14    is a block diagram exemplarily illustrating a hardware configuration of each of the video generation devices  1 ,  1 ′,  1 ″, and  2  in the embodiments. As exemplarily illustrated in  FIG.  14   , the video generation devices  1 ,  1 ′,  1 ″, and  2  of this example each include a central processing unit (CPU)  10   a , an input unit  10   b , an output unit  10   c , a random access memory (RAM)  10   d , a read only memory (ROM)  10   e , an auxiliary storage device  10   f , and a bus  10   g . The CPU  10   a  of this example includes a control unit  10   aa , a computation unit  10   ab , and a register  10   ac  and executes various kinds of arithmetic processing in accordance with various programs read onto the register  10   ac . The input unit  10   b  is an input terminal, a keyboard, a mouse, a touch panel, or the like through which data is input. The output unit  10   c  is an output terminal, a display, a LAN card controlled by the CPU  10   a  having read a predetermined program, or the like through which data is output. The RAM  10   d  is a static random access memory (SRAM), a dynamic random access memory (DRAM), or the like and has a program region  10   da  in which a predetermined program is stored and a data region  10   db  in which various kinds of data is stored. The auxiliary storage device  10   f  is, for example, a hard disk, a magneto-optical disc (MO), or a semiconductor memory and has a program region  10   fa  in which a predetermined program is stored and a data region  10   fb  in which various kinds of data is stored. The bus  10   g  connects the CPU  10   a , the input unit  10   b , the output unit  10   c , the RAM  10   d , the ROM  10   e , and the auxiliary storage device  10   f  to enable information communication therebetween. The CPU  10   a  writes a program stored in the program region  10   fa  of the auxiliary storage device  10   f  to the program region  10   da  of the RAM  10   d  in accordance with a read operating system (OS) program. Similarly, the CPU  10   a  writes various kinds of data stored in the data region  10   fb  of the auxiliary storage device  10   f  to the data region  10   db  of the RAM  10   d . Then, addresses on the RAM  10   d  where the program and the data are written are stored to the register  10   ac  of the CPU  10   a . The control unit  10   aa  of the CPU  10   a  sequentially reads these addresses stored in the register  10   ac , reads the program and the data from regions on the RAM  10   d  indicated by the read addresses, causes the computation unit  10   ab  to sequentially execute computation indicated by the program, and stores a result of the computation in the register  10   ac . With such a configuration, the functional configurations of the video generation devices  1 ,  1 ′,  1 ″, and  2  are achieved. 
     The above-described program may be recorded in a computer-readable recording medium. The computer-readable recording medium is, for example, a non-transitory recording medium. Examples of such a recording medium include a magnetic recording device, an optical disk, a magneto-optical recording medium, and a semiconductor memory. 
     The program is distributed by, for example, selling, trading, or lending a portable recording medium such as a DVD or a CD-ROM in which the program is recorded. Alternatively, the program may be distributed by storing the program in a storage device of a server computer and forwarding the program from the server computer to another computer through a network. As described above, for example, a computer that executes such a program first temporarily stores, in an own storage device, the program recorded in the portable recording medium or forwarded from the server computer. Then, at processing execution, the computer reads the program stored in the own storage device and executes processing in accordance with the read program. Alternatively, as another execution form of the program, the computer may directly read the program from the portable recording medium and execute processing in accordance with the program, or may sequentially execute processing in accordance with a received program each time the program is forwarded from the server computer to the computer. Alternatively, the above-described processing may be executed through what is called an application service provider (ASP) service in which the program is not forwarded from the server computer to the computer and a processing function is achieved only with program execution instruction and result acquisition. Note that the program in the present form includes information that is used for processing by an electronic calculator and equivalent to a program (not a direct command to the computer but data or the like having a property that defines processing at the computer). 
     In each embodiment, the video generation device is configured by executing predetermined programs on a computer, but at least part of their processing contents may be achieved with hardware. 
     Note that the present invention is not limited to the above-described embodiments. For example, in the second embodiment, the still image acquisition unit  22  obtains a still image of a stationary object that is a real object by capturing the stationary object and outputs the obtained still image. However, a stationary object region in which the stationary object is disposed is known when the stationary object is known, and thus the still image acquisition unit  22  may be omitted. In this case, the video generation unit  24  may generate, without using the still image, a video including a background region as the background of the known stationary object region and may output the generated video. The above-described various processing may be not only executed in a temporally sequential manner in accordance with the description but also executed in parallel or individually in accordance with the processing capacity of a device that executes processing or as necessary. In addition, further change is possible as appropriate within the scope of the present invention. 
     REFERENCE SIGNS LIST 
     
         
         
           
               1 ,  1 ′,  1 ″,  2  video generation device